Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Bioassays to Quantify Hygienic Behavior in Honey Bee (Apis Mellifera L.) Colonies : A Review
    Leclercq, Gil ; Francis, Frédéric ; Gengler, Nicolas ; Blacquière, Tjeerd - \ 2018
    Journal of Apicultural Research 57 (2018). - ISSN 0021-8839 - p. 663 - 673.
    Apis mellifera - Ascosphaera apis - bioassays - hygienic behavior - Paenibacillus larvae - Varroa destructor

    Individual immunity in honey bees (Apis mellifera L.) is complemented by highly evolved social behaviors. Among them, hygienic behavior has a key role involving the detection and removal of unhealthy or dead brood. Since the 1960s, several bioassays have been developed to quantify the hygienic behavior of honey bee colonies against chalkbrood, American foulbrood, and varroa infested brood. Here, we review the five main bioassays used since the late 1960s. We describe their advantages and disadvantages, including a special focus on their inherent biases. For each assay, we also discuss whether or not their use should be restricted to quantify the hygienic behavior against chalkbrood, or American foulbrood, or varroa infested brood. Overall, the bioassays involving the removal of freeze-killed brood are recommended over the bioassays relying on the removal of pin-killed brood but only for the quantification of hygienic behavior toward chalkbrood and American foulbrood. These bioassays are not recommended to quantify the hygienic behavior toward varroa infested brood, for which an accurate assessment should rely on assays based on the removal of brood artificially infested with varroa mites. Choosing an appropriate bioassay is crucial for an accurate assessment of the hygienic behavior against a defined pathogen, depending on the research question, or the goal of the breeding program. Bioensayos para cuantificar el comportamiento higiénico en las colonias de abejas melíferas (Apis mellifera L.): una revisión La inmunidad individual de las abejas melíferas (Apis mellifera L.) se complementa con comportamientos sociales altamente evolucionados. Entre ellos, el comportamiento higiénico tiene un papel clave en la detección y eliminación de crías enfermas o muertas. Desde la década de 1960, se han desarrollado varios bioensayos para cuantificar el comportamiento higiénico de las colonias de abejas melíferas frente a la cría infestada de Ascosfera, loque americana y varroa. Aquí revisamos los cinco principales bioensayos utilizados desde finales de la década de 1960. Describimos sus ventajas y desventajas, incluyendo un enfoque especial en sus sesgos inherentes. Para cada ensayo, también discutimos si su uso debe ser restringido o no para cuantificar el comportamiento higiénico contra la cría de loque americana o la cría infestada de varroa. En general, los bioensayos que involucran la eliminación de la cría muerta por congelación son más recomendables que los bioensayos que dependen de la eliminación de la cría muerta por pin, pero sólo para la cuantificación del comportamiento higiénico hacia la cría infestada de Ascosfera y la loque americana. Estos bioensayos no se recomiendan para cuantificar el comportamiento higiénico de la cría infestada de varroa, para lo cual una evaluación precisa debe basarse en ensayos basados en la extracción de la cría infestada artificialmente con ácaros de la varroa. La elección de un bioensayo apropiado es crucial para una evaluación precisa del comportamiento higiénico frente a un patógeno definido, dependiendo de la pregunta de investigación o del objetivo del programa de cría.

    Biological processes induced by ZnO, Amoxicillin, Rye and Fructooligosaccharides in cultured Intestinal Porcine Epithelial Cells : VDI-4; In-vitro tests 2013-2014
    Hulst, M.M. ; Hoekman, A.J.W. ; Wijers, I. ; Schokker, D. ; Smits, M.A. - \ 2015
    Wageningen : Wageningen UR Livestock Research (Livestock Research report 882) - 42
    in vitro - bioassays - epithelium - livestock - feed additives - genes - immunology - in vitro - biotesten - epitheel - vee - voedertoevoegingen - genen - immunologie
    The objective of this study was to develop an in-vitro bioassay using cultured Intestinal Porcine Epithelial Cells (IPEC-J2) and evaluate the capability of this assay to predict enterocyte-specific physiological and immunological processes induced by nutrients/additives in the intestines of farm animals. Responses to five nutrients/feed-additives, similar to those studied in animal trials, performed in the Feed4Foodure framework, were measured by gene expression analysis of IPEC-J2 cells either under stressed (Salmonella) or non-stressed conditions. Response genes were analysed using bioinformatics web-tools in order to identify dominant biological processes induced by these nutrients/feed-additives and to predict key-genes/proteins important for regulation of these biological proc
    Werken aan bodemweerbaarheid
    Broek, R.C.F.M. van den; Berg, W. van den; Lamers, J.G. ; Cuijpers, W.J.M. ; Hospers-Brands, A.J.T.M. ; Smits, S. - \ 2014
    Praktijkonderzoek Plant & Omgeving B.V. - 63
    teeltsystemen - bodemweerbaarheid - bestrijdingsmethoden - agrarische bedrijfsvoering - phytophthora cactorum - bodemeigenschappen - gewasbescherming - proeven - biotesten - fragaria - biologische technieken - vollegrondsteelt - cropping systems - soil suppressiveness - control methods - farm management - phytophthora cactorum - soil properties - plant protection - trials - bioassays - fragaria - biological techniques - outdoor cropping
    De land- en tuinbouw ontwikkelt zich in de richting van steeds intensievere en complexere bedrijfssystemen. Vanuit de sector groeit het besef dat de chemische benadering van ziekten en plagen haar grenzen begint te bereiken. Ook de consument verlangt van de producent dat de inzet van chemische middelen gereduceerd wordt en gezocht wordt naar andere, meer duurzame oplossingen. Een van de oplossingsrichtingen is het creëren van een gezonde, veerkrachtige en weerbare bodem. Op zulke bodems groeit een gezond gewas met een goede opbrengst die minder gevoelig is voor ziekten en plagen en efficiënter omgaat met nutriënten waardoor er minder verliezen optreden. Hierdoor hoeven telers minder gewasbeschermingsmiddelen en nutriënten te gebruiken en kunnen ze, met een beter inkomen, milieuvriendelijker telen. Aardbei is een voorbeeld van een zeer intensieve teelt, die erg gevoelig is voor ziekten en plagen. In de teelt worden relatief veel gewasbeschermingsmiddelen gebruikt, en er is een sterke behoefte aan kennis die de inzet van deze middelen kan beperken. Aardbei is ook een heel geschikt toetsgewas, omdat het sterk reageert op de bodemgezondheid van een perceel. Is deze goed dan ligt de aardbeienproductie veel hoger dan op percelen waarop de bodemgezondheid matig of slecht is. Opbrengstverschillen kunnen oplopen tot meer dan 50%. De verkregen resultaten bij aardbei kunnen ook vertaald worden naar andere vollegronds gewassen.
    Screening van hot spots van nieuwe verontreinigingen : een pilot studie in bodem, grondwater en oppervlaktewater
    Lahr, J. ; Laak, T.L. ter; Derksen, A. - \ 2014
    Wageningen : Alterra (Alterra-rapport 2538) - 87
    bodemverontreiniging - waterverontreiniging - verontreinigende stoffen - toxicologie - geneesmiddelen - ecologische risicoschatting - biotesten - inventarisaties - soil pollution - water pollution - pollutants - toxicology - drugs - ecological risk assessment - bioassays - inventories
    Onder nieuwe verontreinigingen verstaan we stoffen die nog niet of niet volledig zijn gereguleerd en waarvan de milieurisico’s vaak onbekend zijn. Daarbij gaat het om stoffen als natuurlijke hormonen en hormoonverstorende stoffen (weekmakers, detergenten, brandvertragers, e.d.), humane geneesmiddelen, diergeneesmiddelen, nanodeeltjes en microplastics. In de ‘waterwereld’ is altijd meer aandacht besteed aan de nieuwe verontreinigingen dan binnen andere beleidsvelden. In de bodem zijn de aanwezigheid en de mogelijke risico’s grotendeels onbekend. In 2013 heeft een consortium van diverse onderzoeksinstanties en stakeholders een pilotonderzoek uitgevoerd naar de aanwezigheid en mogelijke risico’s van hormonen en geneesmiddelen in het systeem bodem - grondwater - oppervlaktewater.
    GM1-derived carbohydrates for pathogen and antibody detection : synthesis and biological evaluation
    Garcia Hartjes, J. - \ 2014
    Wageningen University. Promotor(en): Han Zuilhof, co-promotor(en): Tom Wennekes. - Wageningen : Wageningen University - ISBN 9789462571273 - 240
    koolhydraten - moleculaire detectie - antilichamen - pathogenen - remmers - biotesten - carbohydrates - molecular detection - antibodies - pathogens - inhibitors - bioassays
    Towards a realistic risk characterization of complex mixtures using in vitro bioassays
    Montano Garces, M. - \ 2013
    Wageningen University. Promotor(en): Tinka Murk, co-promotor(en): A.C. Gutleb. - [S.l.] : s.n. - ISBN 9789461736598
    risicoschatting - persistente organische verontreinigende stoffen - verontreinigde sedimenten - mengsels - biotesten - in vitro - toxiciteit - schildklierhormonen - risk assessment - persistent organic pollutants - contaminated sediments - mixtures - bioassays - in vitro - toxicity - thyroid hormones

    This thesis aims to better understand and further improve the relevance and reliabilityof in vitro bioassaysfor a biobased risk characterisation of complex mixtures, with special focus on persistent organic pollutants (POPs) in sediments.

    In Chapter 1 the importance of complex mixture characterization in modern society is introduced. The methods available, their current advantages and their disadvantages for complex mixture testing are described. With the shift from policy oriented chemical testing towards the inclusion of in vitro bioanalysis, important challenges have to be overcome to ensure a relevant and reliable quantification of the toxic potency of complex mixtures. These challenges are explained in the introduction, including the status of development and validation of those aspects for reliable testing. One of the main advantages that in vitro bioanalysis has to offer is the possibility to quantify the toxic potency of compounds for which chemical analytical methods have not or hardly been developed, for example because standards do not yet exist. Hydroxylated metabolites of POPs are an example of a toxicologically relevant group of compounds that can exert endocrine disrupting effects, but they cannot yet be routinely analysed. A selection of yet unsolved issues are further studied and discussed in this thesis, as outlined in the “approach and structure of the thesis”.

    In Chapter 2 a meta-analysis is performed to study the occurrence and relevance of hydroxylated (OH) compounds in humans and wildlife. Reported body burdens of halogenated phenolic contaminants (HPCs), including OH-POP in different tissues from humans and wildlife species, are reviewed in relation to the concentration of their putative parent compounds to be able to reveal relevant exposure routes and sub-populations at risk. Highest OH-POP levels were found in blood plasma, and highly perfused and fetal tissues. Plasma concentrations of analysed known HPCs ranged from 0.1-100 nM in humans and up to 240, 454, 800 and 7650 nM for birds, fish, cetaceans and other mammals, respectively. Reported metabolite blood plasma levels also are compared with relevant toxicological threshold concentrations from toxicological studies, and appeared to fully fall within the in vitro (0.05–10000 nM) and in vivo (3-940 nM) effect concentrations reported for OH-POPs. Given the sensitivity of early developmental stages, and information lacking about the general population, it is advisable to determine HPC background blood levels in children and fetal tissue .

    Given the toxicological relevance of the OH-POPs, Chapter 3 aims at providing solutions to the long standing problem of the in vitro production and analysis of OH-POP metabolite thyroid hormone disrupting (THD) potency via binding to plasma thyroid hormone binding proteins (THBPs). In sediments and for example seafood, the POPs occur as parent compounds that would only become THD after metabolisation (hydroxylation). Several methods have shown the competitive thyroxine (T4) T4 displacement potency of pure metabolites. However, in vitro metabolization of, among others, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers(PBDEs) followed by in vitro quantification of their potency has encountered drawbacks related to the co-extraction of compounds disturbing the T4-TTR competitive binding assay. The present study identifies and quantifies the major co-extractants, cholesterol and saturated and non-saturated fatty acids (SFA and NSFA), at levels above 20 μM (20 nmol per mg protein in the incubation mixture) following various extraction methods. A new method is presented to in vitro metabolise parent compounds into OH-metabolites followed by selective extraction of metabolites while four-fold reducing co-extraction of the disturbing compounds. In addition a microplate-format non-radioactive fluorescence displacement assay was developed to quantify the TTR binding potency of the metabolites formed. The effectiveness of the in vitro metabolism and extraction of the OH-metabolites of the model compounds CB 77 and BDE 47 was chemically quantified with a newly developed chromatographic method analyzing silylated derivatives of the OH-metabolites and co-extractants. Due to the mentioned improvements, it is now possible to make a dose-response curve up to 50% inhibition with OH-metabolites extracted from bioactivated CB 77 and BDE 47. Without taking the toxic potencies of bio-activated POPs into account with bioanalysis, the hazard and risk posed by POPs will be seriously underestimated.

    The chapters 4 and 5 are committed to tackle the issues of supramaximal (SPMX) responses and sample extract concentration which are crucial to reliably quantify of the toxic potencies of complex mixtures with in vitro bioassays.

    A SPMX effect is the phenomenon that compounds induce a maximum response in an assay that is significantly higher than that of the positive control. As the positive control is used to quantify the toxic potency of a sample, this could result in over-estimation of its toxic potency. As this has been most elaborately reported for in vitro estrogenicity assays, a meta-analysis was performed of such assays, compounds and conditions in which the effect is observed (Chapter 4a).For the 21 natural and industrial chemicals that could be identified as SPMX inducers, the culture and exposure conditions varied greatly among and between the assays. Relevant information on assay characteristics, however, sometimes lacked. Diethylstilbestrol (DES), genistein (GEN) and bisphenol A (BPA) were selected to build a database. The meta-analysis revealed that the occurrence of SPMX effects, could be related to a number of specific assay characteristics: 1) the type and concentration of the serum used to supplement the exposure medium; 2) the endpoint used to quantify the estrogenic potency (endogenous or transfected reporter gene), 3) the number of EREs (estrogen responsive elements) used before the reporter gene, and 4) the nature of the promoter’s. There were no indications that solvent concentration in culture, exposure period or cell model influenced the occurrence of SPMX. It is important to understand the mechanism behind this phenomenon because in vitro assays for estrogenicity are used extensively to characterize and quantify the estrogenic potency of compounds, mixtures and environmental extracts.

    Several SPMX inducers also have been reported to block cellular efflux pumps in vivo and in vitro (Anselmo et al. 2012; Georgantzopoulou et al. 2013). Therefore it was hypothesized that efflux pump blockers present in environmental matrices could increase the internal concentration of bioassay agonists and thus cause the SPMX. In Chapter 4b this hypothesis was tested by adapting a 96-well plate cellular efflux pump inhibition assay (CEPIA) to the H4IIE rat hepatoma cell line used for the DR.Luc reporter gene assay for dioxin-like compounds. The influence of various environmentally relevant efflux pump inhibitors on the 2,3,7,8-tetrachlorodibenzo-p-dioxine (TCDD) response was tested. Under the DR.Luc assay conditions there was no evidence that P-gp efflux pump inhibitors modified or potentiated the activity of TCDD. Neither genistein nor quercetin, two potent SPMX inducers on ER-mediated assays, induced any signal on the DR.Luc assay, nor influenced the luciferase induction by TCDD. Future work should be focused on testing the consequences of efflux pump inhibition with an AhR-agonist which is a P-gp substrate, as this could result in intracellular accumulation of this AhR-agonist.

    It is standard practice to use a high single stock concentration of extracts to further dilute test concentrations from and perform the analysis. However, a high contaminant load in an extract may oversaturate the solubility of the extracted compounds in carrier solvents and overload the clean-up columns which may reduce the efficiency of polyaromatic hydrocarbons (PAHs) elimination from the extract. These problems may cause respectively under- or over-estimation of the quantified dioxin-like toxic potency. Therefore Chapter 5 focuses on the effects of initial stock concentrations, including sonication assisted dissolution and exposure time, on the quantified dioxin-like potency of cleaned nonpolar sediment extracts. Indeed, more than 20 g sediment equivalents (SEQ)/mL DMSO) as initial stock concentrations resulted in underestimation of bio-TEQ levels in the sediments as observed for cleaned nonpolar sediment extracts from various locations in Luxembourg. An overload of extract on clean-up columns caused an over-estimation of the dioxin-like potency at 24 hours of exposure, probably due to limited removal of PAHs that can induce false positive responses in the in vitro assays. Sonication assisted dissolution of the stock before serial dilution strongly reduced the standard variation of the outcomes. Taking into account the aspects revealed in this study, in addition to already described important issues for quality control, the in vitro bioassays based bio-TEQs can be applied in a comprehensive monitoring program to determine whether sediments comply with health and safety standards for humans and the environment. For the generally applied sediment quality criteria, advices are given about maximum initial stock concentrations to achieve reliable bioassay outcomes.

    The methods and concepts developed for metabolic activation of compounds in non-polar sediment extracts and in in vitro analysis of the TTR-competitive binding are applied in Chapter 6 to extracts from highly or less contaminated sediments collected in Luxembourg. Nonpolar fractions of sediment extracts were incubated with S9 rat microsomes, and the metabolites were extracted with a newly developed method that excludes most of the lipids to avoid interference in the non-radioactive 96-well plate transthyretin (TTR) competitive binding assay. Metabolic activation increased the TTR binding potency of nonpolar fractions of POP-polluted sediments up to 100 times, resulting in potencies up to 240 nmol T4 equivalents/g sediment equivalent (nmol T4-Eq/g SEQ). Without bioactivation, medium polar and polar fractions also contained potent TTR-binding compounds with potencies from 1.6 to 17 nmol T4-Eq/g SEQ. This demonstrates that a more realistic in vitro sediment THD risk characterization should also include testing ofboth polar and medium polar sediment extracts for THD, as well as bioactivated nonpolar sediment fractions. Without bioactivation THD potency is not observed in nonpolar sediment extracts, although in in vivo experiments PCBs and PBDEs, and not with dioxins or PAHs, have shown to be thyroid hormone disrupting (THD), demonstrating this bio-activation is toxicologically relevant and therefore required for sediment hazard characterisation.

    Chapter 7 discusses the implications of our results to improve the relevance and reliability of in vitro bioassay applied for risk characterisation of complex mixtures from sediments and other matrices. The evidence obtained to support the relevance of POP bio-activation is considered both from the exposure perspective as well as the toxicity perspective. Various features of the newly developed methods and knowledge acquired within this PhD project are discussed in relation to in vitro bioassay risk characterization of sediments towards a realistic in vitro bioassay-based risk characterization of complex mixtures. Some important aspects for the inclusion of metabolizing systems within in vitro bioassay are discussed. In addition, alternatives to deal with the SPMX effect and the definition of suitable sample amounts to improve in vitro bioassay reliability are offered. The suitability of the developed approach application is considered for the risk characterization of sediments. Furthermore, an analysis is made to decide whether this thesis have made in vitro bioassays more reliable and relevant for risk characterization of complex mixtures. Finally, it provides some concluding remarks and aspects for further applications and research.

    Rododendron spoort Phytophthora op
    Evenhuis, A. - \ 2012
    phytophthora - aardbeien - fruitteelt - kleinfruit - biotesten - gewasbescherming - water - pythium - phytophthora - strawberries - fruit growing - small fruits - bioassays - plant protection - water - pythium
    Poster met onderzoeksinformatie. In dit onderzoek worden blaadjes van Rododendron gebruikt om Phytophthora aan te tonen in water dat gebruikt wordt voor de aardbeienteelt.
    Screening for Modulatory Effects on Steroidogenesis Using the Human H295R Adrenocortical Cell Line: A Metabolomics Approach
    Rijk, J.C.W. ; Peijnenburg, A.A.C.M. ; Blokland, M.H. ; Lommen, A. ; Hoogenboom, L.A.P. ; Bovee, T.F.H. - \ 2012
    Chemical Research in Toxicology 25 (2012)8. - ISSN 0893-228X - p. 1720 - 1731.
    mass-spectrometry - in-vitro - expression - receptor - assay - disruption - inhibitors - chemicals - bioassays - model
    The recently OECD validated H295R steroidogenesis assay provides an in vitro alternative to evaluate the potential interference of exogenous compounds with endogenous steroid hormone synthesis. Currently, this assay is used for a simple negative-positive screening of compounds using testosterone and estradiol levels as end points, measured with specific enzyme immunoassays (EIAs) or targeted liquid chromatography (LC) and gas chromatography (GC)–mass spectrometry (MS) methods. However, recent developments in LC-MS and bioinformatics allow for more comprehensive approaches to evaluate changes in steroid profiles. In the current work, the H295R cell model was combined with a metabolomics approach to monitor changes in metabolite profiles in both a targeted and untargeted way. H295R cells were exposed for 48 h to model compounds, i.e., forskolin, abiraterone, prochloraz, ketoconazole, trilostane, formestane, aminoglutethimide, fadrozole, etomidate, and metyrapone, known to affect steroidogenesis. After exposure, the levels of 9 natural steroids were determined by a quantitative targeted GC-MS/MS method and compared to a metabolomics method using Ultra Performance Liquid Chromatography–Time-of-Flight–Mass Spectrometry (UPLC-ToF-MS). Like the EIAs, both methods were suited for negative-positive screening, but the MS methods also generated specific fingerprints, allowing chemical class prediction of the compound under investigation. Although the targeted GC-MS/MS was more sensitive, which was an advantage regarding analysis of the estrogens 17ß-estradiol and estrone, the untargeted UPLC-ToF-MS was able to evaluate effects on the synthesis of the corticosteroids. Moreover, untargeted comparison of the aligned chemical profiles allowed identification of all m/z-values that are differential between exposed and nonexposed H295R cells. In conclusion, application of a comprehensive metabolite profiling methodology not only provides a tool to screen compounds for steroidogenic modulating properties, but also allows chemical class prediction. As such, steroid profiling methodologies in conjunction with the H295R assay can contribute to the prioritization of chemicals for additional safety testing.
    Development and validation of in vitro bioassays for thyroid hormone receptor mediated endocrine disruption
    Freitas, J. de - \ 2012
    Wageningen University. Promotor(en): Tinka Murk; Ivonne Rietjens, co-promotor(en): J.D. Furlow. - [S.l.] : s.n. - ISBN 9789461734372 - 192
    hormoonverstoorders - biotesten - in vitro - schildklierhormonen - endocrine disruptors - bioassays - in vitro - thyroid hormones

    Thyroid hormones regulate crucial processes in vertebrates such as reproduction, development and energy metabolism. Endocrine disruption via the thyroid hormone system is gaining more attention both from scientists and regulators, because of the increasing incidence of hormone-related cancers and developmental defects, and the requirement that newly marketed compounds are tested for thyroid hormone disruption. To reduce the number of experimental animals used and to increase the insight into the mechanisms of toxic interference with the thyroid hormone receptor function, we developed and validated functional in vitro bioassays for thyroid hormone receptor-mediated toxicity. These assays enable quick identification and quantification of specific thyroid hormone receptor disrupting potency of compounds and contribute to the further establishment of a battery of in vitro tests for hazard identification of thyroid active compounds.

    Gewasbeschermingsmiddelen, waterkwaliteit en risicobeoordeling bij toelating
    Brock, T.C.M. - \ 2012
    Gewasbescherming 43 (2012)4. - ISSN 0166-6495 - p. 112 - 117.
    oppervlaktewater - pesticiden - waterverontreiniging - landbouw - ecotoxicologie - biotesten - kwaliteitsnormen - toelating van bestrijdingsmiddelen - besluitvorming - surface water - pesticides - water pollution - agriculture - ecotoxicology - bioassays - quality standards - authorisation of pesticides - decision making
    Eén van de doelstellingen van het toelatingsbeleid van gewasbeschermingsmiddelen is te voorkomen dat, na goede landbouwkundige toepassing, deze middelen en hun omzettingsproducten een schadelijke uitwerking hebben op waterorganismen. Het kan verbazing wekken dat in watergangen de waterkwaliteitsnormen voor gewasbeschermingsmiddelen nog regelmatig overschreden worden, daar een strikt omschreven toelatingsbeleid is geïmplementeerd en diverse technische maatregelen zijn genomen om emissie van gewasbeschermingsmiddelen naar oppervlaktewater te voorkomen (o.a. drift reducerende sproeidoppen; bufferzones). Er wordt door sommigen geopperd dat het toelatingsbeleid niet geheel voldoet. Reden genoeg om nader in te gaan op recente ontwikkelingen bij de aquatische risicobeoordeling van gewasbeschermingsmiddelen in het kader van de toelating.
    Nematoden als indicator voor de waterkwaliteit
    Sollie, S. ; Kluck, J. ; Hooff, A. van; Helder, J. - \ 2012
    H2O : tijdschrift voor watervoorziening en afvalwaterbehandeling 45 (2012)14/15. - ISSN 0166-8439 - p. 48 - 50.
    waterkwaliteit - oppervlaktewater - biologische monitoring - waterbodems - nematoda - biotesten - water quality - surface water - biomonitoring - water bottoms - nematoda - bioassays
    Het beoordelen van de waterkwaliteit is een lastige zaak. Vaak wordt de chemische kwaliteit bepaald, maar eigenlijk willen we weten welke effecten die heeft op de biologische kwaliteit. Veld- en microscopisch onderzoek aan biologische indicatoren is bewerkelijk en bovendien zijn de resultaten niet eenduidig. Met de ontwikkeling van DNA-analysetechnieken is het mogelijk geworden nematoden in de waterbodem snel en accuraat te analyseren. Nematoden zijn kleine aaltjes (lengte 0,3 tot 1,0 mm) die in grote aantallen en met een aanzienlijke diversiteit in de waterbodem aanwezig zijn. De combinatie van hoge dichtheden en grote verscheidenheid maakt de nematodengemeenschap tot potentiële bio-indicator voor de waterkwaliteit. Een pilot liet zien dat DNA-analyse van nematoden in de waterbodem duidelijke signalen van eutrofiëring aangaf en daarmee inzicht gaf in de waterkwaliteit.
    Maximale opsporingskans voor Meloidogyne chitwoodi
    Beers, T.G. van; Gastel-Topper, A.W.W. van - \ 2011
    actieplan aaltjesbeheersing
    meloidogyne chitwoodi - biotesten - aardappelen - bodemonderzoek - bemonsteren - akkerbouw - meloidogyne chitwoodi - bioassays - potatoes - soil testing - sampling - arable farming
    Brochure over het opsporen van Meloidogyne chitwoodi met behulp van een biotoets.
    Geringe besmetting goed zelf op te sporen
    Gastel-Topper, A.W.W. van; Korthals, G.W. - \ 2011
    Boerderij/Akkerbouw 97 (2011)11. - ISSN 0169-0116 - p. E14 - E15.
    meloidogyne chitwoodi - biotesten - plantenparasitaire nematoden - bodempathogenen - bodemonderzoek - akkerbouw - aardappelen - pootaardappelen - meloidogyne chitwoodi - bioassays - plant parasitic nematodes - soilborne pathogens - soil testing - arable farming - potatoes - seed potatoes
    PPO ontwikkelde een biotoets om Meloidogyne chitwoodi op te sporen. Deze toets doer de teler zelf en geeft meer zekerheid dan een laboratoriumtoets.
    Tailored Microarray Platform for the Detection of Marine Toxins
    Bovee, T.F.H. ; Hendriksen, P.J.M. ; Portier, L. ; Wang, S. ; Elliott, C.T. ; Egmond, H.P. van; Nielen, M.W.F. ; Peijnenburg, A.A.C.M. ; Hoogenboom, L.A.P. - \ 2011
    Environmental Science and Technology 45 (2011)20. - ISSN 0013-936X - p. 8965 - 8973.
    harmful algal blooms - human health - shellfish toxins - microplate assay - climate-change - okadaic acid - bioassays - cyanobacteria - yessotoxins - polyether
    Currently, there are no fast in vitro broad spectrum screening bioassays for the detection of marine toxins. The aim of this study was to develop such an assay. In gene expression profiling experiments 17 marker genes were provisionally selected that were differentially regulated in human intestinal Caco-2 cells upon exposure to the lipophilic shellfish poisons azaspiracid-1 (AZA1) or dinophysis toxin-1 (DTX1). These 17 genes together with two control genes were the basis for the design of a tailored microarray platform for the detection of these marine toxins and potentially others. Five out of the 17 selected marker genes on this dedicated DNA microarray gave clear signals, whereby the resulting fingerprints could be used to detect these toxins. CEACAM1, DDIT4, and TUBB3 were up-regulated by both AZA1 and DTX1, TRIB3 was up-regulated by AZA1 only, and OSR2 by DTX1 only. Analysis by singleplex qRT-PCR revealed the up- and down-regulation of the selected RGS16 and NPPB marker genes by DTX1, that were not envisioned by the new developed dedicated array. The qRT-PCR targeting the DDIT4, RSG16 and NPPB genes thus already resulted in a specific pattern for AZA1 and DTX1 indicating that for this specific case qRT-PCR might a be more suitable approach than a dedicated array
    Development of aquatic biomonitoring models for surface waters used for drinking water supply
    Penders, E.J.M. - \ 2011
    Wageningen University. Promotor(en): Ivonne Rietjens, co-promotor(en): Gerrit Alink; W. Hoogenboezem. - [S.l.] : S.n. - ISBN 9789461731012 - 176
    biologische monitoring - oppervlaktewater - drinkwater - waterkwaliteit - genotoxiciteit - rijn - waterverontreiniging - biotesten - watervoorziening - biomonitoring - surface water - drinking water - water quality - genotoxicity - river rhine - water pollution - bioassays - water supply
    Given the need for continued quality control of surface waters used for the production of drinking water by state-of-the-art bioassays and biological early warning systems, the objective of the present thesis was to validate and improve some of the bioassays and biological early warning systems used for quality control of surface water. Although there is a decline in the (geno)toxicity of surface waters over the years as observed for example for the water from the River Rhine over last decades, there is still a need for continued quality control. Due to the lower (geno)toxicity, bioassays with increased sensitivity are needed
    Ontwikkeling biotoets voor de detectie van het quarantaineaaltje Meloidogyne chitwoodi : proefuitvoering in de nematodentuin op PPO-AGV, 2010
    Gastel, A.W.W. van; Visser, J.H.M. ; Korthals, G.W. - \ 2011
    Kennisakker.nl 2011 (2011)16 nov.
    plantenparasitaire nematoden - meloidogyne chitwoodi - detectie - biotesten - akkerbouw - pootaardappelen - plant parasitic nematodes - meloidogyne chitwoodi - detection - bioassays - arable farming - seed potatoes
    Doel van dit onderzoek is het ontwikkelen van een biotoets waarmee lage besmettingen van het quarantaine aaltje M. chitwoodi voorafgaand aan de aardappelteelt betrouwbaar kunnen worden gedetecteerd. Deze toetsmethode wordt ontwikkeld voor gebruik door telers op hun bedrijf en/of in de kas.
    Ontwikkeling biotoets voor de detectie van het quarantaineaaltje Meloidogyne chitwoodi : proefuitvoering in de nematodentuin op PPO AGV, 2010
    Gastel-Topper, A.W.W. van; Visser, J.H.M. ; Korthals, G.W. - \ 2011
    Lelystad : Praktijkonderzoek Plant & Omgeving B.V. - 20
    plantenparasitaire nematoden - meloidogyne chitwoodi - biotesten - detectie - akkerbouw - aardappelen - pootaardappelen - plant parasitic nematodes - meloidogyne chitwoodi - bioassays - detection - arable farming - potatoes - seed potatoes
    De doelstelling van dit onderzoek is het ontwikkelen van een biotoets waarmee lage besmettingen van het quarantaine aaltje Meloidogyne chitwoodi voorafgaand aan de pootaardappelteelt of ander vermeerderingsmateriaal betrouwbaar kunnen worden gedetecteerd, in de grond of door middel van symptomen op een gevoelig gewas, zoals aardappel. Deze toets methode wordt ontwikkeld voor gebruik door telers op hun bedrijf. Voor de biotoets is aardappel als toets gewas gebruikt. Door na het groeiseizoen de aardappelen te beoordelen kan door de mogelijk ontwikkelde symptomen (op de knol) inzicht worden verkregen in de aanwezigheid van Meloidogyne chitwoodi en/of bemonstering van de grond.
    Can time-weighted average concentrations be used to assess the risks of metsulfuron-methyl to Myriophyllum spicatum under different time-variable exposure regimes?
    Belgers, J.D.M. ; Aalderink, G.H. ; Arts, G.H.P. ; Brock, T.C.M. - \ 2011
    Chemosphere 85 (2011)6. - ISSN 0045-6535 - p. 1017 - 1025.
    aquatic plants - sulfonylurea herbicides - macrophytes - sensitivity - pesticides - toxicity - bioassays - growth - model
    We tested the effects of the herbicide metsulfuron-methyl on growth of the submerged macrophyte Myriophyllum spicatum under laboratory conditions using different exposure scenarios. The exposures of each scenario were comparable in the concentration×time factor, viz., the same 21-d time-weighted average (TWA) concentrations but variable in peak exposure concentrations (ranging from 0.1 to 21000ngaiL(-1)) and exposure periods (1, 3, 7, 14 or 21d). To study recovery potential of the exposed M. spicatum plants we continued the observation on shoot and root growth for another 21d in herbicide-free medium so that the total observation period was 42d. Non-destructive endpoints, length and number of new shoots and roots, were determined weekly from day 14 onwards. Destructive endpoints, dry-weight (DW) of main shoots, new shoots and new roots, were measured at the end of the experiment (t=42d). Metsulfuron-methyl exposure in particular inhibited new tissue formation but was not lethal to main shoots. On days 21 and 42 after start exposure, EC(10)/EC(50) values for new tissues expressed in terms of peak concentration (=measured concentration during exposure periods of different length) showed large differences between exposure scenarios in contrast to EC(10)/EC(50) values for days 21 and 42 expressed in terms of 21-d and 42-d TWA concentrations, respectively. At the end of the experiment (day 42), 42-d TWA EC(x) values were remarkably similar between exposure scenarios, while a similar trend could already be observed on day 21 for 21-d TWA EC(x) values. For the macrophyte M. spicatum and exposure to the herbicide metsulfuron-methyl the TWA approach seems to be appropriate to use in the risk assessment. However, the data from the toxicity experiment suggest that on day 21 also the absolute height of the pulse exposure played a (minor) role in the exposure - response relationships observed
    Opheffen groeiremming als onderdeel van emissie-reductie
    Maas, Bram van der - \ 2011
    cropping systems - closed systems - drainage water - water reuse - greenhouse horticulture - water treatment - bioassays
    Nieuwe bacterieziekte lijkt op Xanthomonas: Stenotrophomonas veroorzaker zwarte vaten in radijs
    Arkesteijn, M. ; Ludeking, D.J.W. - \ 2011
    Onder Glas 8 (2011)5. - p. 59 - 59.
    glastuinbouw - radijsjes - bacterieziekten - biotesten - biologische technieken - stenotrophomonas - cultuurmethoden - groenten - greenhouse horticulture - radishes - bacterial diseases - bioassays - biological techniques - stenotrophomonas - cultural methods - vegetables
    Sinds 2007 heeft een aantal telers last van een nieuwe ziekte in radijs. Symptomen zijn misvormde knollen, uitval, extra wortelgroei en vooral zwarte vaten in het knolletje. Over de verspreiding is nog weinig bekend. Deze bacterieziekte treedt pleksgewijs op.
    Optimization and prevalidation of the in vitro ER alpha CALUX method to test estrogenic and antiestrogenic activity of compounds
    Burg, B. van der; Winter, R. ; Weimer, M. ; Berckmans, P. ; Suzuki, G. ; Gijsbers, L. ; Jonas, A. ; Linden, S. van der; Witters, H. ; Aarts, J.M.M.J.G. ; Legler, J. ; Kopp-Schneider, A. ; Bremer, S. - \ 2010
    Reproductive Toxicology 30 (2010)1. - ISSN 0890-6238 - p. 73 - 80.
    cell-line - transactivation assay - endocrine disruptors - bioassays - androgen - chemicals - panel - beta
    Estrogenicity of chemicals has received significant attention and is linked to endocrine-disrupting activities. However, there is a paucity of validated methods to assess estrogenicity in vitro. We have established a robust method to test estrogenic and antiestrogenic activity of compounds in vitro, as an alternative to using animal models such as the uterotrophic assay. To this end we optimized protocols to be used in combination with CALUX reporter gene assays and carried out an in house prevalidation, followed by two rounds of tests to establish transferability. Problems in the initial test with transferability were solved by isolation of a novel cell clone of the ER alpha CALUX line with greatly improved stability and luciferase levels. This cell line proved to be a very suitable and reliable predictor of estrogenicity of chemicals and was able to readily rank a range of chemicals on the basis of their EC50 values.
    Bodemweerbaarheid biedt perspectieven
    Os, G.J. van - \ 2010
    Syscope Magazine 2010 (2010)28. - p. 24 - 24.
    bodemweerbaarheid - bodembiologie - veldproeven - organische stof - biotesten - gewasbescherming - soil suppressiveness - soil biology - field tests - organic matter - bioassays - plant protection
    Tien Noord-Hollandse bollentelers zijn zo geïnteresseerd geraakt door onderzoek van Gera van Os naar bodemweerbaarheid, dat ze zelf een praktijkproef hebben opgezet. Al in het eerste jaar zijn er positieve effecten.
    Hormonal effects of prohormones : novel approaches towards effect based screening in veterinary growth promoter control
    Rijk, J.C.W. - \ 2010
    Wageningen University. Promotor(en): Michel Nielen; Ivonne Rietjens, co-promotor(en): Maria Groot; Ad Peijnenburg. - [S.l. : S.n. - ISBN 9789085858195 - 207
    groeibevorderaars - hormonen - biotesten - metabolisme - metabolomica - growth promoters - hormones - bioassays - metabolism - metabolomics
    Within the European Union the use of growth promoting agents in cattle fattening is prohibited according to Council Directive 96/22/EC. Interestingly, there is not a black list of substances, but 96/22/EC states that all substances having thyrostatic, estrogenic, androgenic or gestagenic activity are prohibited. Besides abuse of the “classical” synthetic steroids there is a tendency towards misuse of natural steroids and prohormones. Prohormones are compounds that exhibit limited or no hormonal activity but are direct precursors of bioactive hormones and are intended to be converted to full active hormones via enzymatic processes in the body. However, knowledge about metabolism, the mode of action and excretion profiles in cattle is often unclear, and methods to detect abuse of prohormones in livestock production are lacking. Therefore, the aim of this thesis was to get insight into the hormonal action of prohormones and to develop novel in vitro and in vivo screening methods allowing effective surveillance on the illegal use of prohormones in livestock production. Hereby the emphasis was on developing effect based approaches to better meet Council Directive 96/22/EC.
    The bioactivity of a wide variety of supplements which contained prohormones were tested using a yeast androgen bioassay. For supplements containing solely prohormones the value of this bioactivity based screening appeared to be limited as they require metabolism to become active. Therefore, screening methods for animal feed, supplements and preparations were set-up by using the same yeast androgen bioassay in combination with bovine liver models as well as enzymatic and chemical deconjugation procedures to mimic in vivo metabolic bioactivation. The use of either bovine liver S9, liver slices, pure enzymes or alkaline hydrolysis showed that prohormones could be activated, resulting in a significant increase in bioactivity as determined by the androgen yeast bioassay.
    For the detection of prohormone abuse at the farm and/or slaughterhouse the usefulness of ‘omics’ based profiling techniques was investigated. Within this scope a comprehensive metabolomics based screening strategy for steroid urine profiling was developed. Comparison of urinary profiles revealed large differences between the profiles of controls and dehydroepiandrosterone (DHEA) as well as pregnenolone treated animals. Moreover this steroid urine profiling approach allowed identification of biomarkers for treatment by specific prohormones. This resulted in respectively 7 and 12 specific mass peak loadings which could potentially be used as biomarkers for pregnenolone and DHEA treatment.
    In addition, the feasibility of a liver gene expression profiling approach was investigated to monitor the effects of DHEA treatment at the transciptome level. It was shown that identification and application of genomic biomarkers for screening of DHEA abuse in cattle is substantially hampered by biological variation. On the other hand, it was demonstrated that comparison of pre-defined gene sets versus the whole genome expression profile of an animal allows to distinguish DHEA treatment effects from variations in gene expression due to inherent biological variation.
    Altogether the results of this thesis increase the knowledge about the metabolism and bioactivation of prohormones in vitro as well as in vivo. Based on this knowledge, a panel of new effect based concepts and screening methods was developed that complement and improve the current testing programs. These new concepts will facilitate better implementation of the European ban on growth promoters in livestock production as described in Council Directive 96/22/EC.


    Soil suppressiveness of Meloidogyne, Verticillium and Pythium in diverse agricultural soils: possible mechanisms, and options for sustainable management
    Wurff, A.W.G. van der; Stooten, M. van; Hamelink, R. ; Bohne, S. ; Wensveen, W. van; Os, G.J. van; Postma, J. ; Bloem, J. - \ 2010
    Gewasbescherming 41 (2010)3. - ISSN 0166-6495 - p. 141 - 141.
    meloidogyne incognita - pythium aphanidermatum - verticillium dahliae - biotesten - bodemweerbaarheid - glastuinbouw - meloidogyne incognita - pythium aphanidermatum - verticillium dahliae - bioassays - soil suppressiveness - greenhouse horticulture
    Grond uit veertien verschillende glastuinbedrijven is door middel van biotoetsen getest op ziektewerend vermogen tegen drie belangrijke pathogenen, namelijk Meloidogyne incognita, Pythium aphanidermatum and Verticillium dahliae.
    Eerste resultaten onderzoek zwarte vaatbundels in radijs
    Hofland-Zijlstra, J.D. ; Janse, J. ; Wensveen, W. van; Pham, K.T.K. - \ 2010
    radijsjes - plantenziekteverwekkers - biotesten - xanthomonas - moleculaire detectie - radishes - plant pathogens - bioassays - xanthomonas - molecular detection
    Poster met onderzoeksinformatie naar de oorzaak van zwarte vaatbundels in radijs.
    Vervolgonderzoek ecologische risico's Noorderbos : chemische en biologische beschikbaarheid van chroom : rapportage fase 2
    Groenenberg, J.E. ; Bloem, J. ; Faber, J.H. ; Dijcker, R. - \ 2009
    Wageningen : Alterra (Alterra-rapport 1998) - 47
    bossen - bodemverontreiniging - ecologie - risico - zware metalen - chroom - monitoring - biologische beschikbaarheid - biotesten - toxicologie - nederland - ecotoxicologie - noord-brabant - forests - soil pollution - ecology - risk - heavy metals - chromium - monitoring - bioavailability - bioassays - toxicology - netherlands - ecotoxicology - noord-brabant
    Dit rapport beschrijft de resultaten van het vervolgonderzoek van de chemische en biologische monitoring van de ernstig met chroom vervuilde bodem van het Noorderbos in Tilburg. Er is specifiek aandacht besteed aan de chemische en biologische beschikbaarheid van metalen met name van chroom waarvan de speciatie in oplossing gemeten is. De belangrijkste conclusie van het onderzoek is dat zowel de chemische als de biologische beschikbaarheid van chroom laag zijn. Met de gebruikte bio-sassays werden geen toxische effecten vastgesteld.
    Topsoil+ Bodemweerbaarheid
    Os, Gera van - \ 2009
    ornamental bulbs - organic matter - bioassays - soil biology - soil suppressiveness - soil biodiversity
    Application of a direct toxicity assessment approach to assess the hazard of potential pesticide exposure at selected sites on the Crocodile and Magalies rivers, South Africa.
    Ansara-Ross, T. ; Wepener, V. ; Brink, P.J. van den; Ross, M.J. - \ 2009
    African Journal of Aquatic Science 34 (2009)3. - ISSN 1608-5914 - p. 207 - 217.
    whole effluent toxicity - risk-assessment - daphnia-magna - danio-rerio - water - bioassays - classification - substances - framework - larvae
    The potentially hazardous effects of agricultural pesticide usage in the Crocodile (west) Marico catchment were evaluated using the Danio rerio and Daphnia pulex lethality, Selenastrum capricornutum growth inhibition and the Ames mutagenicity plate incorporation assays. Hazard assessment categories are proposed to standardise the output of the different toxicity assessments. Sites were categorised according to the toxicity hazard indicated and were related to the gradients of agricultural land-use intensity at each site. Intensive agricultural sites showed the highest effects to all tested biota. Receiving water at urban sites associated with increased nutrients and lowest pesticide usage showed few adverse effects, while the relatively unimpacted site indicated no hazard to any organism, and only a slight stimulation to algal growth. Weighted hazard scores indicated that the unimpacted sites were least hazardous, falling within a B category, the urban sites were moderately hazardous (C category), and the agricultural sites (D category) had the highest potential impacts on aquatic organisms. This study demonstrated the usefulness of using the hazard assessment approach and the role it could play in assessing site-specific potential toxicity hazards of river water impacted by agrochemicals. It can be used together with other assessment methods, such as biological indices, in a tiered approach.
    Identification of unknown residues : using bioassay directed fractionation, UPLC/TOFMS analysis and database searching
    Peters, R.J.B. ; Rijk, J.C.W. ; Oosterink, J.E. ; Nijrolder, A.W.J.M. ; Nielen, M.W.F. - \ 2009
    Wageningen : Rikilt - Institute of Food Safety (Report / RIKILT 2009.013) - 47
    residuen - analytische methoden - biotesten - vloeistofchromatografie - massaspectrometrie - residues - analytical methods - bioassays - liquid chromatography - mass spectrometry
    Nowadays a large number of compounds are determined in environmental and food samples. Biological tests are used to screen samples for large groups of compounds having a particular effect, but it is often difficult to identify a specific compound when a positive effect is observed. The identification of an unknown compound is a challenge for analytical chemistry in environmental analysis, food analysis, as well as in clinical and forensic toxicology. This study reports on the development of a procedure for the identification of unknown residues in samples suspected of containing illegal substances and samples showing bioactivity in bioassay - or microbiological screening assays. For testing purposes several samples were selected; a number of so-called "cold cases", historical samples that were suspected of containing illegal growth promoting substances, herbal mixtures and sport supplements.
    KNPV-werkgroep Phytophthora & Pythium : Uitbreiding van een biotoets voor Phytophthora cactorum in aanrdbei naar een toets voor ziektewering
    Lamers, J.G. - \ 2009
    Gewasbescherming 40 (2009)5. - ISSN 0166-6495 - p. 254 - 254.
    proeven op proefstations - biotesten - fruitteelt - aardbeien - phytophthora cactorum - ziektepreventie - gewasbescherming - station tests - bioassays - fruit growing - strawberries - phytophthora cactorum - disease prevention - plant protection
    Uitbreiding van een biotoets voor Phytophthora cactorum in aardbei naar een toets voor ziektewering
    Optimaliseren van biotoetsen voor het meten van bodemweerbaarheid van Verticillium dahliae en Pythium spp.
    Schreuders, H. ; Wurff, A.W.G. van der - \ 2009
    Gewasbescherming 40 (2009)5. - ISSN 0166-6495 - p. 256 - 256.
    plagenbestrijding - pesticiden - biotesten - milieubescherming - verticillium dahliae - peronosporales - plantenziekteverwekkers - gewasbescherming - bodemweerbaarheid - pest control - pesticides - bioassays - environmental protection - verticillium dahliae - peronosporales - plant pathogens - plant protection - soil suppressiveness
    In de grondgebonden teelten is de bestrijding van ziektes een lastig probleem doordat steeds meer chemische bestrijdingsmiddelen niet meer gebruikt mogen worden. Daarnaast zijn milieuvriendelijke oplossingen belangrijk. De competentie van de bodem om ziekten en plagen te onderdrukken wordt hierdoor steeds interessanter. De biotoets is op dit moment de enige manier om bodemweerbaarheid te meten
    Biotoets voor chitwoodi
    Gastel, A.W.W. van; Korthals, G.W. - \ 2009
    Nieuwe oogst / Magazine gewas 5 (2009)12. - ISSN 1871-093X - p. 7 - 7.
    akkerbouw - meloidogyne chitwoodi - biotesten - biologische technieken - bemonsteren - nematodenbestrijding - arable farming - meloidogyne chitwoodi - bioassays - biological techniques - sampling - nematode control
    In het kader van het Actieplan Aaltjesbeheersing van het Productschap Akkerbouw werkt Praktijkonderzoek Plant en Omgeving (PPO) aan de ontwikkeling van een biotoets waarmee telers zelf kunnen nagaan of een perceel besmet is met het maïswortelknobbelaaltje (Meloidogyne chitwoodi). De biotoets blijkt gevoeliger te zijn dan de gebruikelijke onderzoeksmethoden. Zeer lage besmettingen van het maïswortelknobbelaaltje, die via een grondmonster vaak niet worden gevonden, kunnen daardoor met de biotoets wel worden aangetoond
    Comparing the sensitivity of four bioassays for acrolein
    Sneekes, A.C. ; Kaag, N.H.B.M. - \ 2009
    Den Helder : IMARES (Report / Wageningen IMARES no. C026.09) - 14
    schepen - waterballast - waterzuivering - acroleïne - biotesten - ecotoxicologie - ships - water ballasting - water treatment - acrolein - bioassays - ecotoxicology
    Introduction of non-indigenous species is a risk associated with discharge of ballast water from ships transporting cargo between regions. The IMO has set out a mandatory framework for ballast water management on board ships. EnvioMar GmbH has developed a Ballast Water Treatment System (BWTS) using acrolein as active substance. The toxicity of the active substance, as well as the residual toxicity of the treated ballast water has to be assessed, according to IMO regulations on BWTS using active ingredients (G9). EnvioMar asked IMARES to conduct bioassays in order to assess the toxicity of the treated ballast water and the active ingredient, acrolein.
    Bodemweerbaarheidstoets voor Rhizoctonia solani
    Postma, J. ; Schilder, M.T. - \ 2009
    Gewasbescherming 40 (2009)2. - ISSN 0166-6495 - p. 81 - 82.
    proeven op proefstations - biotesten - biologische technieken - thanatephorus cucumeris - ziektedistributie - akkerbouw - bodemweerbaarheid - vollegrondsteelt - station tests - bioassays - biological techniques - thanatephorus cucumeris - disease distribution - arable farming - soil suppressiveness - outdoor cropping
    Reeds vele jaren wordt de bodemweerbaarheidstoets die door Pedro Oyarzun werd ontwikkeld met succes toegepast om de ziektewering van verschillende bodems tegen Rhizoctonia solani met elkaar te vergelijken. Deze toets wordt onder gestandaardiseerde condities uitgevoerd in een klimaatcel. Alle gronden worden bij een gelijke vochtspanning (pF 1,7 = -50 mbar) getoetst
    Effects of chronic exposure to low-level herbicide concentrations in mesocosms
    Arts, G.H.P. ; Belgers, D. ; Buijse-Bogdan, L.L. ; Boonstra, J. ; Rhenen-Kersten, C.H. van; Sinkeldam, J.A. - \ 2009
    herbiciden - biotesten - milieueffect - effecten - risicoschatting - mesocosmossen - herbicides - bioassays - environmental impact - effects - risk assessment - mesocosms
    Poster met informatie uit onderzoek naar de effecten op lange termijn van lage concentraties herbiciden op mesocosmossen
    Discussie over het thema - biotoetsen voor het meten van ziekteonderdrukking in grond
    Postma, J. ; Os, G.J. van - \ 2009
    Gewasbescherming 40 (2009)2. - ISSN 0166-6495 - p. 85 - 85.
    proeven op proefstations - biotesten - biologische technieken - genetische parameters - ziekteresistentie - vollegrondsteelt - station tests - bioassays - biological techniques - genetic parameters - disease resistance - outdoor cropping
    Dit thema biotoetsen voor het bepalen van ziekteonderdrukking leverde een veelheid aan verschillende voordrachten op, waarbij de inzichten en aanpak sterk werden bepaald door het doel waarvoor de biotoets gebruikt wordt. Combinatie van biotoetsen die door verschillende onderzoekers gebruikt worden, zou uiteindelijk kunnen leiden tot een soort 'modelset' voor de bepaling van bodemgezondheid
    Extrapolatie van resultaten uit biotoetsen
    Os, G.J. van; Bent, J. van der - \ 2009
    Gewasbescherming 40 (2009)2. - ISSN 0166-6495 - p. 79 - 80.
    proeven op proefstations - bloembollen - biotesten - biologische technieken - ziekteresistentie - extrapolatie - bodemweerbaarheid - station tests - ornamental bulbs - bioassays - biological techniques - disease resistance - extrapolation - soil suppressiveness
    Bij PPO bloembollen zijn biotoetsen gebruikt om ziektewering vast te stellen in grond met drie organische-stofniveaus. Deze zijn aangelegd in een veldexperiment, uitgevoerd in het project TopSoil+ waarin onder andere gekeken wordt naar de effecten van organische stof op de bodemkwaliteit van duinzandgrond. In 2005 zijn proefvelden aangelegd met drie organische-stofniveaus: 0,7% (oorspronkelijk gehalte), 1,4% en 4,0%
    Biotoetsen als een van de mogelijkheden om bodemgezondheid te meten en te begrijpen
    Korthals, G.W. ; Visser, J.H.M. - \ 2009
    Gewasbescherming 40 (2009)2. - ISSN 0166-6495 - p. 78 - 79.
    biotesten - biologische technieken - experimenteel veldonderzoek - compost - groenbemesters - bodembiologie - grondbewerking - organische stof - thanatephorus cucumeris - akkerbouw - bodempathogenen - biologische grondontsmetting - vollegrondsteelt - bioassays - biological techniques - field experimentation - composts - green manures - soil biology - tillage - organic matter - thanatephorus cucumeris - arable farming - soilborne pathogens - biological soil sterilization - outdoor cropping
    In het onderzoek komt steeds meer aandacht voor aspecten die te maken hebben met algehele bodemgezondheid. Er zijn verschillende grote projecten, zoals de Bodemgezondheidsproef te Vredepeel, waarbij geprobeerd wordt om de Bodemgezondheid te verbeteren. Binnen WUR zijn inmiddels verschillende biotoetsen ontwikkeld. In ons veldonderzoek zijn verschillende biotoetsen gebruikt om in het veld extra waarnemingen te kunnen doen aan de effectiviteit van verschillende maatregelen
    Organische stof en ziektewering in de sierteelt
    Os, G.J. van; Bent, J. van der; Conijn, C.G.M. - \ 2009
    Gewasbescherming 40 (2009)1. - ISSN 0166-6495 - p. 22 - 22.
    gewasbescherming - organische stof - zandgronden - biotesten - meloidogyne hapla - pratylenchus penetrans - pythium - thanatephorus cucumeris - narcissus - tulipa - hyacinthus - sierteelt - bodemkwaliteit - plant protection - organic matter - sandy soils - bioassays - meloidogyne hapla - pratylenchus penetrans - pythium - thanatephorus cucumeris - narcissus - tulipa - hyacinthus - ornamental horticulture - soil quality
    Resultaten uit lopend onderzoek naar de effecten van organische stof op de bodemkwaliteit van duinzandgrond en de haalbaarheid van geïntegreerde en biologische teelten met een gewasrotatie van 1:7 met bolgewassen, heesters en vaste planten
    Toxiciteit van oliefracties in sediment voor Corophium volutor
    Kaag, N.H.B.M. ; Sneekes, A.C. ; Koelmans, A.A. ; Peeters, E.T.H.M. - \ 2009
    Den Helder : IMARES (Rapport / Wageningen IMARES C008/09) - 19
    aquatische toxicologie - mineraaloliën - sedimenttest - milieueffect - corophium - biotesten - chemische analyse - verontreinigende stoffen - experimenteel veldonderzoek - olieverontreinigingen - aquatic toxicology - mineral oils - sediment test - environmental impact - corophium - bioassays - chemical analysis - pollutants - field experimentation - oil spills
    Naar aanleiding van toxiciteitexperimenten zijn milieu risicogrenzen voor minerale olie afgeleid, waarbij onderscheid wordt gemaakt naar fracties op basis van kookpunt (lengte van de koolstofketens). In dit onderzoek is onderzocht in hoeverre de voorgestelde risicogrenzen overeenkomen met waargenomen toxiciteit in veldsedimenten. Het oliegehalte werd in deze sedimenten bepaald door middel van XAD-extracties, waarmee het snel desorberend gehalte werd bepaald. Toxiciteit werd bepaald met een 10-daagse test met de slijkgarnaal Corophium volutator.
    Groeiresponstest voor recirculatiewater - Stap 1: Opzet van een Biotoets
    Blok, C. - \ 2008
    irrigatie - irrigatiewater - irrigatieuitrusting - zuiveren - reinigers - scheiding - wassen (activiteit) - biotesten - voedingsstoffen - voedingsoplossingen - groeivertragers - plantengroeiregulatoren - hergebruik van water - irrigation - irrigation water - irrigation equipment - purification - scrubbers - separation - washing - bioassays - nutrients - nutrient solutions - growth retardants - plant growth regulators - water reuse
    De methoden worden gecombineerd toegepast, waarbij methode A als voorselectie wordt gebruikt. Hiermee worden voedingsoplossingen getest bij binnenkomst. Als er een verdachte voedingsoplossing gevonden wordt, starten de testen B en C. Tegen het einde van de testen B en C wordt test A herhaald om na te gaan of de groeiremming op het zelfde niveau aanwezig blijft, of dat de groeiremming afneemt in de tijd (en dus de metingen met methode B en C anders beoordeeld moeten worden
    Cultivation of the heart urchin Echinocardium cordatum and validation of its use in marine toxicity testing for environmental risk assessment
    Schipper, C.A. ; Dubbeldam, M. ; Feist, S.W. ; Rietjens, I.M.C.M. ; Murk, A.J. - \ 2008
    Journal of Experimental Marine Biology and Ecology 364 (2008)1. - ISSN 0022-0981 - p. 11 - 18.
    paracentrotus-lividus echinodermata - sea-urchin - north-sea - corophium-volutator - growth - sediments - bioassays - echinoidea - organisms - amphipod
    To study environmental risk assessment, echinoderms provide a useful model for ecotoxicological testing. However, limited knowledge of the life history of field collected heart urchins is a problem and the use of cultured urchins has been investigated here. The present study describes a culture method for the heart urchin Echinocardium cordatum under controlled laboratory conditions, providing organisms with a low biological variation. Based on our optimized growth protocol both larvae and juveniles have a growth rate comparable to E. cordatum in the wild. The toxicological response of cultured and field-collected E. cordatum was compared in standard saltwater toxicity bioassays. Using ammonium chloride as a water-soluble reference toxicant, mean 96 h LC50 values for cultured heart urchins versus field collected animals were 37.4 ± 7.6 mg NH4+/l (n = 5) versus 22.5 ± 4.9 mg NH4+/l (n = 19), respectively. Additional toxicity experiments with tributyl tin (TBT) spiked sediments revealed 14d LC50 values of 1,242 (95% confidence interval 986¿1,564) and 964 (95% confidence interval 843¿1,102) µg Sn/kg dw respectively in cultured and field collected E. cordatum. From this it was concluded that cultured heart urchins are less sensitive to TBT than field collected E. cordatum. Furthermore in whole sediment toxicity tests, survival of cultured sea urchins was higher or at least similar to that of field collected E. cordatum. The increased sensitivity of field urchins compared to cultured urchins in various toxicity tests may be due to multiple environmental stressors reducing their overall performance. Overall it was demonstrated that the use of cultured E. cordatum provides a significant advance for urchin-based bioassays for marine environmental toxicity testing, resulting in a more homogeneous, vital population with experimental data displaying reduced variability.
    Time and concentration dependency in the potentially affected fraction of species: the case of hydrogen peroxide treatment of ballast water
    Smit, M.G.D. ; Ebbens, E. ; Jak, R.G. ; Huijbregts, M.J.A. - \ 2008
    Environmental Toxicology and Chemistry 27 (2008)3. - ISSN 0730-7268 - p. 746 - 753.
    sensitivity distributions - toxicity - superoxide - bioassays - membrane - biology
    Transport of large volumes of ballast water contributes greatly to invasions of species. Hydrogen peroxide (H2O2) can be used as a disinfectant to prevent the spread of exotic species via ballast water. Instead of using environmental risk assessment techniques for protecting a certain fraction of the species from being affected, the present study aimed to apply these techniques to define treatment regimes of H2O2 and effectively eliminate as many species as possible. Based on time-dependent dose¿response curves for five marine species (Corophium volutator, Artemia salina, Brachionus plicatilis, Dunaliella teriolecta, and Skeletonema costatum), time-dependent species-sensitivity distributions (SSDs) were derived for different effect sizes. The present study showed that H2O2 can be used effectively to treat ballast water but that relatively high concentrations and long treatment durations are required to eliminate the vast majority of species in ballast water. The described toxicant effectiveness approach using SSDs also has other potential fields of application, including short-term application of biocides.
    A new highly androgen specific yeast biosensor, enabling optimisation of (Q)SAR model approaches
    Bovee, T.F.H. ; Lommerse, J.P.M. ; Peijnenburg, A.A.C.M. ; Fernandes, E.A. ; Nielen, M.W.F. - \ 2008
    Journal of Steroid Biochemistry and Molecular Biology 108 (2008)1-2. - ISSN 0960-0760 - p. 121 - 131.
    ligand-binding domains - estrogenic activity - receptor ligands - response element - in-vitro - assay - validation - mutations - bioassays - agonists
    Recently we constructed recombinant yeast cells that express the human androgen receptor (hAR) and yeast enhanced green fluorescent protein (yEGFP), the latter in response to androgens. When exposed to 17ß-testosterone, the concentration where half-maximal activation is reached (EC50) was 50 nM. Relative androgenic potencies (RAP), defined as the ratio between the EC50 of 17ß-testosterone and the EC50 of the compound, were 1.7, 1.2 and 0.008 for 19-nortestosterone, tetrahydrogestrinone and 17ß-estradiol respectively. Steroids representative for other hormone receptors, like estrone, 17¿-ethynylestradiol, and diethylstilbestrol for the estrogen receptor and corticosterone and dexamethasone for the glucocorticoid receptor, showed no agonistic response. Only compounds known to exert androgenic effects give a response. Determined RAPs were in line with results obtained from optimised QSAR model calculations and demonstrated that Saccharomyces cerevisiae showed no metabolism of test compounds and displayed no crosstalk from endogenous hormone receptors. The suitability of this bioassay to verify the outcomes of (Q)SAR models to predict the activities of different steroids was further examined by studies with steroid isomers and a number of designer steroids, confirming that the 17ß-hydroxyl group, 3-keto group and 5¿-steroidal framework are extremely important for the activity of the androgenic steroid.
    Assessment of the toxicity of the solid coating PV1 in a marine invironment, using biotests with algae, a rotifer and a bacteria
    Foekema, E.M. ; Sneekes, A.C. - \ 2007
    IJmuiden : IMARES Texel (Rapport / Wageningen IMARES nr. C059/07) - 19
    afdeklagen - marien milieu - toxische stoffen - biotesten - uitspoelen - bacteriën - algen - rotifera - aquatische toxicologie - coatings - marine environment - toxic substances - bioassays - leaching - bacteria - algae - rotifera - aquatic toxicology
    The toxic potential of substances that may leach from the solid coating PV1 was tested using • the marine bacteria Vibrio fisheri in the Microtox® Basic test • the marine algae Skeletonema costatum in a 72h algal growth inhibition test • the marine rotifer Brachionus plicatilis in the 24 h ROTOX® test The tests were performed with the water accommodated fraction (WAF) of the coating in natural seawater. This WAF was produced following a method that is commonly applied for the production of WAFs in toxicity testing with oil. Solid coating material that was scrapped of a metal plate was mixed for 24 hours in filtered natural seawater in a ratio of 1 mg coating per 1 ml seawater. For a normal coated surface this is the equivalent of 4 ml seawater per 1 cm2 coated surface. The coating material was removed from the solution before exposure in the ecotoxicity tests. A control sample was prepared by collecting the material that was scrapped of a 20 cm2 area of a metal plate that was not coated with PV1, but underwent the same pre-treatment (phosphated) as the plate that was actually coated for the production of the test sample. This control sample was tested in the bacteria test and in the rotifer test. The algal growth test required more test material, that was therefore scraped from a metal plate with a relatively thick layer of coating. The scraping was performed in such a way that not the whole coating was removed and thus no control sample was necessary in this test.
    Testing Toxicity of Ballast Water treated by the Greenship Ballast Water Treatment System
    Kaag, N.H.B.M. ; Sneekes, A.C. - \ 2007
    Den Helder : IMARES (Rapport / Wageningen IMARES nr. C091/07) - 33
    schepen - transport over water - waterballast - chemische behandeling - geïntroduceerde soorten - waterverontreiniging - biotesten - algen - artemia - solea - aquatische ecosystemen - ships - water transport - water ballasting - chemical treatment - introduced species - water pollution - bioassays - algae - artemia - solea - aquatic ecosystems
    Stenotrophomonas maltophilia: a new potential biocontrol agent of Ralstonia solanacearum, causal agent of potato brown rot
    Messiha, N.A.S. ; Diepeningen, A.D. van; Farag, N.S. ; Abdallah, S.A. ; Janse, J.D. ; Bruggen, A.H.C. van - \ 2007
    European Journal of Plant Pathology 118 (2007)3. - ISSN 0929-1873 - p. 211 - 225.
    geneesmiddelresistentie - antibiotica - biologische bestrijding - zware kleigronden - bedrijfsvoering - stenotrophomonas maltophilia - ralstonia solanacearum - aardappelen - biotesten - antagonisten - drug resistance - antibiotics - biological control - clay soils - management - stenotrophomonas maltophilia - ralstonia solanacearum - potatoes - bioassays - antagonists - biological-control - pseudomonas-solanacearum - bacterial wilt - fluorescent pseudomonads - eucalyptus-urophylla - erwinia-carotovora - pythium-ultimum - rhizosphere - soils - survival
    Stenotrophomonas maltophilia was isolated from the rhizosphere of eggplant in the Nile Delta of Egypt, and its antagonistic potential against Ralstonia solanacearum race 3 biovar 2, the causal agent of potato brown rot, was in vitro evaluated on KB agar medium and in vivo on potato plants. In vitro, four isolates of S. maltophilia (PD3531, PD3532, PD3533, and PD3534) appeared antagonistic. The isolate (PD3533) was screened as the most promising antagonist for the in vivo tests. In the greenhouse, the antagonist was applied directly to soil or by bacterization of potato eyepieces. Stenotrophomonas maltophilia significantly suppressed potato brown rot in Egyptian clay soil but not in Dutch clay soil. Survival of a rifampicin and chloramphenicol-resistant S. maltophilia strain PD4560 was investigated in two pairs of clay soils, conventionally and organically managed, from Egypt and the Netherlands. The survival of S. maltophilia was significantly less in Dutch than in Egyptian soils, while the converse occurred for R. solanacearum. These results are in agreement with those obtained in the in vivo biocontrol tests. In conclusion, S. maltophilia may be useful for control of brown rot in the area where it was originally isolated, the Nile Delta in Egypt.
    Simulation of potato late blight in the Netherlands: validation of the blightspace model reveals dichotomy in the epidemiological effects of resistance components
    Skelsey, P. ; Werf, W. van der; Rossing, W.A.H. ; Holtslag, A.A.M. - \ 2007
    In: Proceedings of the Tenth Workshop of an European Network for Development of an Integrated Strategy of Potato Late Blight, Bologna (Italy), special report no. 12. - Lelystad : Applied Plant Research - p. 161 - 164.
    phytophthora infestans - aardappelen - solanum tuberosum - resistentiemechanismen - biotesten - modellen - phytophthora infestans - potatoes - solanum tuberosum - resistance mechanisms - bioassays - models
    Contribution to Proceedings
    The use of green waste compost in peat-based potting mixtures: Fertilization and suppressiveness against soilborne diseases
    Gaag, D.J. van der; Noort, F.R. van; Stapel-Cuijpers, L.H.M. ; Kreij, C. de; Termorshuizen, A.J. ; Rijn, E. van; Zmora-Nahum, S. ; Chen, Y. - \ 2007
    Scientia Horticulturae 114 (2007)4. - ISSN 0304-4238 - p. 289 - 297.
    biologische landbouw - sierplanten - gewasbescherming - fusarium - turf - compost - afvalcompost - phytophthora cinnamomi - cylindrocladium - rhizoctonia - lupinus - spathiphyllum - begonia - biotesten - organic farming - ornamental plants - plant protection - fusarium - peat - composts - refuse compost - phytophthora cinnamomi - cylindrocladium - rhizoctonia - lupinus - spathiphyllum - begonia - bioassays - pathogens - media
    Twelve commercially produced Dutch green waste composts were evaluated for their suitability to replace 20% (v/v) peat substrate in the cultivation of ornamentals. Salt concentrations were determined in water extracts of the composts and disease suppressive effects were assessed against various soilborne diseases. The Cl-concentration of the compost extract appeared to be the limiting factor for use of the composts in potting mixtures. The Cl-concentrations in 7 and 1 composts, respectively, were too high to replace 20% of peat for growing salt sensitive and moderately salt sensitive plants, according to guidelines set for these groups of plants. The suppressive effects of the composts were tested in peat-based potting mixtures using three bioassays: Phytophthora cinnamomi¿lupin, Cylindrocladium spathiphylli¿Spathiphyllum and Rhizoctonia solani AG2-1¿cauliflower. Disease levels in compost-amended mixtures were compared with the non-amended controls. None of the composts induced suppressiveness against P. cinnamomi; 3 and 9 composts significantly induced suppressiveness against C. spathiphylli and R. solani, respectively. No significant disease enhancement was observed in any of the bioassays. The pH of the potting mixture showed a negative correlation with suppression of the Rhizoctonia disease (R2 = 0.56). The effect of pH (pH 4¿6) on suppression of R. solani and P. cinnamomi was further studied in non-amended peat. Disease suppression of R. solani in cauliflower decreased with increasing pH in two different kinds of peat, while there was no effect on P. cinnamomi. The suppressive effect of 3 composts was assessed in two experiments against Fusarium wilt in Cyclamen persicum (caused by F. oxysporum f. sp. cyclamini) and Begonia eliator (caused by F. foetens) under near-commercial conditions. None of the composts had a significant effect on Fusarium wilt in Cyclamen. Two and 3 composts significantly induced suppressiveness against Fusarium wilt in Begonia in the first and second experiments, respectively. No significant differences were observed in growth characteristics between Begonia plants grown in compost-amended and non-amended potting mixture in both experiments. In the second experiment, Cyclamen plants grown in compost-amended potting mixture had significant lower number of flowers than plants grown in non-amended potting mixture, which may have been due to lower concentrations of N in the compost-amended potting mixtures. In conclusion, most composts of the origin and composition tested can replace 20% peat in potting mixtures for moderately salt sensitive and salt tolerant plants. Amendment of these composts can contribute to control of Fusarium wilt in Begonia plants.
    Host plant odours enhance the responses of adult banana weevil to the synthetic aggregation pheromone Cosmolure+
    Tinzaara, W. ; Gold, C.S. ; Dicke, M. ; Huis, A. van; Ragama, P.E. - \ 2007
    International Journal of Pest Management 53 (2007)2. - ISSN 0967-0874 - p. 127 - 137.
    cosmopolites-sordidus - rhynchophorus-palmarum - field activity - coleoptera - curculionidae - attraction - identification - bioassays - beetle
    Attraction of adult banana weevil, Cosmopolites sordidus to volatiles from banana pseudostem tissue and the synthetic pheromone Cosmolure+ presented singly or in combination, was studied in the laboratory and in the field. Olfactometric studies in the laboratory showed that 50 g of fermented banana pseudostem tissue was as attractive as pheromone but more attractive than 50 g of fresh pseudostem tissue. In the laboratory, volatiles from pseudostem tissue had an additive effect on attraction of weevils to the pheromone but the effect was not significant in the field. Field trials, however, showed that attractiveness to weevils was positively correlated with the amount of fermented tissue added to the pheromone. The results indicate that fresh or fermented pseudostem tissue may enhance pheromone trap catches but the effect was not large enough to warrant their deployment for the optimisation of the infochemical-based trapping system for the management of C. sordidus.
    Vervolgonderzoek ecologische risico's Noorderbos; rapportage fase 1
    Groenenberg, J.E. ; Bouwman, L.A. ; Kools, S.A.E. ; Bloem, J. ; Hendriks, W. - \ 2007
    Wageningen : Alterra (Alterra-rapport 1413) - 45
    bossen - bodemverontreiniging - zware metalen - chroom - verzuring - ecologie - risico - biotesten - noord-brabant - forests - soil pollution - heavy metals - chromium - acidification - ecology - risk - bioassays - noord-brabant
    Om inzicht te krijgen in de gevolgen van verzuring op de mobiliteit en toxiciteit van de met chroom, arseen en zware metalen verontreinigde bodem is een deel van de in eerder onderzoek aangelegde veldplots in het Noorderbos te Tilburg kunstmatig verzuurd.
    A practical and low cost microbiotest to assess the phytotoxic potential of growing media and soil
    Blok, C. ; Persoone, G. ; Wever, G. - \ 2006
    fytotoxiciteit - biotesten - biologische technieken - groeimedia - microbiologie - phytotoxicity - bioassays - biological techniques - growing media - microbiology
    A good biotest should provide the possibility to grow plants in close contact with the material to test but without interference of the physical characteristics of the latter. To achieve optimal implementation the biotest should be simple and cheap. A new microbiotest (called Phytotoxkit) has been developed to meet these demands and has been compared with a more traditional biotest
    Organische stof en bodemweerbaarheid
    Reuler, H. van - \ 2006
    Wageningen : Wageningen UR (Informatieblad Topsoil+ / Wageningen UR 7) - 2
    ziekteresistentie - bodembiologie - weerstand - bodemchemie - duinen - droge stof - zandgronden - pathogenen - meloidogyne hapla - biotesten - bodemvruchtbaarheid - bodemkwaliteit - bodemweerbaarheid - disease resistance - soil biology - resistance - soil chemistry - dunes - dry matter - sandy soils - pathogens - meloidogyne hapla - bioassays - soil fertility - soil quality - soil suppressiveness
    Om de invloed van het organisch stof gehalte op de bodemweerbaarheid te meten zijn in het innovatieproject Topsoil+ drie teeltsystemen aangelegd met een verschillend organisch stof gehalte (0,7; 1,4 en 4,0%). Met behulp van biotoetsen wordt bekeken of het organische stofgehalte van invloed is op de bodemweerbaarheid.
    Temporal Dynamics of Effect Concentrations
    Alda Alvarez, O. ; Jager, T. ; Nuñez Colao, B. ; Kammenga, J.E. - \ 2006
    Environmental Science and Technology 40 (2006)7. - ISSN 0013-936X - p. 2478 - 2484.
    nematode caenorhabditis-elegans - toxicity tests - bioconcentration kinetics - risk-assessment - model - ecotoxicology - consequences - populations - chemicals - bioassays
    In effect assessment the comparability and applicability of LCx and ECx values, which are calculated at single points in time during exposure, relies on the ability to perform a valid extrapolation to other time points of interest. The behavior of LCx in time has been extensively studied, and the behavior of ECx in time is expected to follow similar dynamics, as it is considered that the LCx is just a specific case of ECxs. However, most models have focused on validating the dynamics of LCx, and hardly anything is known about the time dependence of ECx for other endpoints or whether it is comparable to that of LCxs. We have created four scenarios where we study the dynamics of the ECx for different endpoints and how it is affected by the characteristics of two different compounds (carbendazim and pentachlorobenzene) and of two different life history strategies (hermaphroditic and sexually reproducing strains of Caenorhabditis elegans). The observed patterns of behavior in time of the ECx for body size and for reproduction showed unexpected dynamics that deviate considerably from that of the LCx. It was demonstrated that the temporal dynamics of ECx were very different for each particular endpoint. The shape of the ECx-time curves depends on the intrinsic characteristics of the endpoint of study, as well as on the characteristics of the compound and life history strategy of the organism. This makes extrapolation in time or between endpoints difficult and hampers the comparability of results based on this summary statistic. The interpretation of the results from toxicity tests can be improved through process-based modeling, as demonstrated on the current data set
    Habitat selection by chironomid larvae: fast growth requires fast food
    Haas, E.M. de; Wagner, C. ; Koelmans, A.A. ; Kraak, M.H.S. ; Admiraal, W. - \ 2006
    Journal of Animal Ecology 75 (2006)1. - ISSN 0021-8790 - p. 148 - 155.
    floodplain lake-sediments - riparius meigen - community composition - tentans diptera - toxicity tests - organic-matter - particle-size - bioassays - invertebrates - avoidance
    1. Sediments have been considered as a habitat, a cover from predators and a source of food, but also as a source of potential toxic compounds. Therefore, the choice of a suitable substrate is essential for the development of chironomids. 2. For the midge Chironomus riparius (Meigen 1804) the growth rate of larvae has often been related to the food quality in sediments rather than to the amount of toxicants in the sediment. Both food quality and sediment-bound toxicants have been reported to determine the field distribution of chironomid larvae. 3. We therefore studied the habitat selection by C. riparius larvae of floodplain lake sediments, differing in both food quality and concentrations of sediment-bound toxicants. We offered the different sediments pairwise to the chironomid larvae in a choice experiment and their settlement in the paired sediments was determined after 10 days. 4. It was observed that larvae showed a clear preference for sediments with higher food quality, which also provided better growth conditions, and that the food quality overruled avoidance of the sediments with higher toxicant concentrations. 5. Our observations correspond with the persistence of this fast growing opportunistic chironomid species in organically enriched aquatic ecosystems independent of the contamination level.
    Development, validation and routine application of the in vitro REA and DR-CALUX reporter gene bioassays for the screening of estrogenic compounds and dioxins in food and feed
    Bovee, T.F.H. - \ 2006
    Wageningen University. Promotor(en): Ivonne Rietjens; Ron Hoogenboom; Michel Nielen. - [S.l.] : S.n. - ISBN 9789085043935 - 133
    biotesten - dioxinen - oestrogenen - bioassays - dioxins - oestrogens
    A dedicated cell-line was developed by the Department of Toxicology of Wageningen University in a joined project with the University of California in Davis and the RIKILT-WUR - Institute of Food Safety in Wageningen. This DR-CALUX ® bioassay was tested, optimised and validated for its use to determine low elevated levels of dioxins in bovine milk around the existing limits. It was shown that this mammalian cell based test is very sensitive for 2,3,7,8-substituted dioxins and related PCBs, thereby reflecting the relative potencies (TEF) of these compounds as set by the World Health Organisation (WHO). These toxic equivalency factors (WHO-TEFs) express the toxicity of a compound in comparison to the most toxic compoundcongener 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, TEF=1). The response obtained with a mixture of dioxins was additive, in accordance with the TEQ-principle. Milk fat was isolated by centrifugation followed by clean-up of the fat with n-pentane, removal of the fat on a 33% H2SO4silica column, and determination of Ah receptor agonist activity with the DR-CALUX ® bioassay. To investigate the performance of this 33% H2SO4silica method, milk fat was cleaned with activated carbon and spiked with a mixture of 17 different 2,3,7,8-substituted PCDD and PCDF congeners at 1, 3, 6, 9, 12 and 15 pg WHO-TEQ per g fat, as confirmed by GC/MS. In this concentration range, the method showed a recovery of TEQs around 67% (58-87%). The reproducibility showed a coefficient of variation (CV) varying between 4% and 54%, with the exception of the sample spiked at 1 pg WHO-TEQ/g (CV 97%). The repeatability determined with the sample spiked at 6 pg WHO-TEQ per g showed a CV of 10% These results clearly demonstrate that the reproducibility of the silica-CALUX procedure with samples containing more than 1 pg WHO-TEQ per g fat is relatively good, in particular regarding the fact that no internal standards could be used in the assay for correction of data for varying recoveries. The fact that the CV was much higher for the sample spiked at the lowest level, confirmed the calculated limit of quantification of 1 pg WHO-TEQ per g fat. The current tolerance limit for bovine milk in the EU is 3 pg WHO-TEQ per g fat, with an action limit of 2 pg WHO-TEQ per g fat. Therefore, the DR-CALUX ® bioassay can be a useful pre-screening tool for selecting milk samples that may contain dioxin levels exceeding this tolerance limit. This was supported by the results obtained with 22 field samples, since all five samples exceeding the 2 pg WHO-TEQ per g fat concentration gave a higher response in the DR-CALUX ® bioassay.

    The DR-CALUX ® bioassay in combination with the 33% H2SO4clean-up procedure results in a specific test for the determination of dioxins and dioxin-like PCBs, allowing the screening of relatively large sets of samples for the presence of unacceptable high levels of these compounds. This results in a reduction of costs involved in the analysis of food for the presence of these compounds, enabling more intense monitoring programs.

    Following the successful optimisation and validation of the test for milk fat, the bioassay was first used at RIKILT in the food and feed area during the 1998 Brazilian citrus pulp incident. The test procedure was subsequently optimised and validated for animal feed. During the German bakery waste incident in 2003, animal feed was contaminated with dioxins due to the use of waste wood for drying of the material. Besides Germany, the material was also shipped to the Netherlands. Levels up to 12 ng WHO-TEQ/kg were detected, being about 15 times over the current limit of 0.75 ng WHO-TEQ/kg. A combined strategy of screening with the DRCALUX ® -bioassay and the HRGC/HRMS confirmatory method was used in the Netherlands to rapidly control the incident. Pigs were contaminated by the incident but only to a very limited extent. Despite the rather low limits for pig meat (1 pg WHO-TEQ per g fat), the DR-CALUX ® bioassay, in combination with an extra acid pre-treatment of the fat samples, showed excellent performance, confirming once again the value of this bioassay. Shown during the recent incidents with kaolinic clay (2004) and the contaminated HCl used for gelatine production (2006), the assay is still the best availablescreening test for dioxins and dioxin-like PCBs.

    The second aim of the research in this thesis was to develop, validate and apply a new recombinant yeast screen to detect chemicals with an estrogenic mode of action in animal feed, urine and illegal preparations. A recombinant yeast cell that stably expresses the human estrogen receptor α (hERα) and yeast enhanced green fluorescent protein (yEGFP) as a reporter protein in response to estrogens was developed at the RIKILT. The EC50 revealed by the RIKILT yeast Estrogen bioAssay (REA) was 0.5 nM for 17b-estradiol and was comparable with reported EC50 values for yeast estrogen bioassays that contain β-galactosidase as a reporter. However, the yEGFP assay can be performed completely in 96 well plates within 4 hours and does not need require cell wall disruption, nor does it need the addition of a substrate. This makes the test sensitive, rapid and convenient with high reproducibility and small variation. The robustness and ease of the yeast cells in combination with the qualities ofyEGFP,ensure that the assay will be suited to be used as a high through put system.

    The properties of the RIKILT yeast Estrogen bioAssay expressing thehERα(REA) were further studied by testing a series of estrogenic compounds. In addition, a similar assay was developed based on the stable expression of human estrogen receptor β (hERβ). When exposed to 17b-estradiol, the maximum transcriptional activity of the hERb cytosensor was only about 40% of the activity observed with hERa, but the concentration where half-maximal activation is reached (EC50), was about 5 times lower. The relative estrogenic potencies (REP), defined as the ratio between the EC50 of 17b-estradiol and the EC50 of the compound, of the synthetic hormones dienestrol, hexestrol and especially mestranol were higher with ERa than with ERβ, while DES was slightly more potent with ERb. The gestagens progesterone and medroxyprogesterone-acetate showed no response, whereas the androgen testosterone showed a very weak response and only at high concentrations. The isoflavones genistein, genistin, daidzein and daidzin, the coumestran coumestrol and the flavonoid naringenin were relatively more potent with ERb than with ERa. Coumestrol and genistein were by far the most potent of these compounds with ERb. However, 8-prenylnaringenin, a phytoestrogen present in hops, was relatively more potent with ERa than with ERb and was actually the most potent phytoestrogen with ERa. The data demonstrate that the REA shows clear dose-response curves when exposed to estrogenic compounds. Since good dose-response curves can be obtained after only 4 h of exposure, the often questioned permeability of the yeast cell wall does not seem to be an obstacle in our yeast estrogen bioassays.

    The RIKILT yeast Estrogen bioAssay stably expressing human estrogen receptor α (REA) was validated as a qualitative screening method for the determination of estrogenic activity in calf urine and animal feed. These validations were performed according to EC Decision 2002/657, which prescribes the determination of the detection capability (CCb), the specificity and the stability. To determine these performance characteristics, twenty blank urine samples of 19 week old calves were collected and spiked with 17b-estradiol (E2b) at 1 ng/ml-1, diethylstilbestrol (DES) at 1 ng/ml-1, 17a-ethynylestradiol (EE2) at 1 ngml-1a-zearalanol at 50 ngml-1 or mestranol at 10 ng/ml-1. Following enzymatic deconjugation and solid phase extraction, 100 ml equivalents of these blank and spiked urine samples were screened for estrogenic activity in a 96 well plate using the REA. All of these blank and low estrogen spiked feed samples fulfilled the CCα and CCβ criterions, meaning that all 20 blank urine samples gave a signal below the determined decision limit CCα and were thus classified as compliant and at least 19 out of the 20 spiked samples gave a signal above this CCα (β=5%) and were thus classified as suspect. The specificity of the method was determined with blank urine samples spiked with a high dose of testosterone or progesterone (1000 ng/ml-1). No response to these substances was detected in the REA. There was also no interference of a high dose of testosterone or progesterone on the response of a low dose of the estrogens. Stability of urine samples was checked with spiked urine samples that were kept frozen for up to 90 days, showing that urine samples could be stored at -20°C for up to 60 days without changing the screening result of the assay. The assay was validated for animal feed in a simalar way, using twenty blank animal feed samples, including milk replacers and wet and dry feed samples.

    As all the performance characteristics met the criteria that were put forward in EC Decision 2002/657 for validation of a qualitative screening method, the described clean-up/yeast estrogen bioassay procedures were proven to be valid for the determination of estrogenic activity in calf urine and animal feed. The clean-up procedures for urine and feed samples are relatively simple and the yeast estrogen bioassay, using yEGFP as a reporter protein, is sensitive, rapid, convenient and reproducible. Due to the good sensitivity of the bioassay, only 2 ml of urine or 1 gram of feed were enough to be processed. Combined this resulted in a low cost bioassay that is suited to be used as a high through-put system for the screening of estrogenic activity in calf urine and animal feed. Like the DR CALUX ® assay, Tthe method acquired an ISO 17025 accreditation status in the Netherlands for both of these matrices. The examples of the MPA-incident with wet pig feed and the fishfeed,described in Chapter 7 of the thesis, demonstrate the applicability of the bioassay method as an early warning system for pharmaceutical waste and hormone use respectively. This is the first successful example of a developed, validated and applied bioassay for the screening of hormonal substances in feed. At present this method has been in routine use at RIKILT for more than two years.

    Overall the work presented in this thesis shows that bioassays are valuable tools for rapid and high throughput screening of samples for both known and unknown compounds. As such they may contribute to an earlier detection of new emerging risks and prevent the use of illegal growth-promoting agents with thus far unknown identity.
    Nader onderzoek baggerspecie Rotterdamse haven: TIE-fase II onderzoek
    Leonards, P.E.G. ; Kwadijk, C.J.A.F. ; Brandsma, S.H. ; Hesselingen, J.M. van - \ 2005
    IJmuiden : RIVO (Rapport /Nederlands Instituut voor Visserij Onderzoek (RIVO) C083.05) - 22
    havens - bagger - toxiciteit - biotesten - rotterdam - harbours - dredgings - toxicity - bioassays - rotterdam
    Baggerslib wordt momenteel niet alleen chemisch maar ook biologisch met bioassays beoordeeld. Een van de gebruikte assays is de DR-CALUX die reageert op verbindingen met een dioxine-achtige toxiciteit. In 2005 zijn in een aantal slibmonsters verhoogde DR-CALUX activiteiten gemeten. Nader onderzoek was daarom gewenst om de verhoogde toxiciteit te verklaren. In het onderhavige onderzoek werd een eerste aanzet tot het nader onderzoek gegeven. Nagegaan werd of een groep van niet-klassieke dioxine-achtige verbindingen (o.a. PAK’s, imidazolen, pyridines, diaryltriazenen) verantwoordelijk kunnen zijn voor de verhoogde DR-CALUX activiteit. Het onderzoek richtte zich op de validatie van de extractie- en zuiveringsmethode (zogenaamde SPECIE-07-E protocol) die gebruikt werden voor het isoleren van de verbindingen uit het slib.
    Bioassay responses and effects on benthos after pilot remediations in the delta of the rivers Rhine and Meuse
    Besten, P.J. den; Brink, P.J. van den - \ 2005
    Environmental Pollution 136 (2005)2. - ISSN 0269-7491 - p. 197 - 208.
    sediment - decontaminatie - biotesten - verontreinigingsbeheersing - schoonmaken - delta's - waterbodems - rijn - maas - zuid-holland - sediment - decontamination - bioassays - pollution control - cleaning - deltas - water bottoms - river rhine - river meuse - zuid-holland - fresh-water microcosms - zooplankton - community
    Chemical and biological monitoring was carried out for 5 years following pilot remediations at two locations in the Rhine-Meuse delta. The remediations consisted of partial excavation of the contaminated sediments, followed by applying a clean layer of sandy material on top. After the remediation, a new silty sediment top layer was formed exhibiting a lower toxicity in five sediment/sediment pore water bioassays. Compared to the unremediated sites, lower metal and PAH concentrations were found at the remediated sites, but in one location at the same time elevated HCH, PCB and HCB levels were recorded. One year after the remediation, the differences became smaller, although effects-based classification showed that the remediated site showed a higher quality up to the last year. In both remediated sites a rapid recolonization of nematodes, oligochaetes and chironomids was observed, while the recolonization by bivalves was slower. A few years after the remediation the differences decrease.
    Analyzing the causes for the persistence of chironomids in flood plain lake sediments
    Haas, E.M. de; Haaren, R. van; Koelmans, A.A. ; Kraak, M.H.S. ; Admiraal, W. - \ 2005
    Archiv für Hydrobiologie 162 (2005)2. - ISSN 0003-9136 - p. 211 - 228.
    sediment - verontreinigende stoffen - chironomus riparius - benthos - waterverontreiniging - stroomvlakten - zware metalen - meren - biotesten - nederland - ecotoxicologie - waterbodems - rijn - waal - sediment - pollutants - chironomus riparius - benthos - water pollution - floodplains - heavy metals - lakes - bioassays - netherlands - ecotoxicology - water bottoms - river rhine - river waal - quality triad approach - benthic invertebrates - community composition - marine sediment - riparius larvae - toxicity - diptera - river - deformation
    The aim of the present study was to analyse the causes for the absence and persistence of chironomids in sediments with a complex pollution history. Observations on the benthic community composition in floodplain lake sediments of the River Rhine, differing in contaminant level and food quality, were combined with laboratory and in situ bioassays, using the midge Chironomus riparius as a model species. The positive relation between food quality and the diversity of the communities indicated that food quality is an important factor regulating benthic community composition, overriding the potential effects of contaminants. Nevertheless, in sediments with high contaminant levels, high densities of species classified as 'pollution-tolerant', such as Chironomus sp., were observed. The laboratory bioassays verified that the contaminant concentrations in these sediments had no direct effect on survival and growth of C. riparius, although higher contaminant concentrations in the sediment resulted in a higher incidence of mentum deformities. Also, the high growth rate of C. riparius in the in situ enclosures in two of the most contaminated sediments indicated chemical stress and mentum deformities did not exclude rapid growth. This observation agrees with the abundance of the resident pollution-tolerant chironomids of the Chironomus plumosus group. In addition, the in situ bioassay pointed out that predation on chironomids added to the field enclosures was significant and is also an important factor in regulating the abundance of chironomids. In sediments with the highest food quality and low levels of contaminants the opportunistic chironomids may have been outcompeted by benthic invertebrate taxa that are not able to persist at more contaminated sites. It is concluded that tolerance of opportunistic chironomids, such as Chironomus sp., combined with their rapid rate of development, enables them to persist in contaminated sediments that are organically enriched avoiding competition with other invertebrates
    Assessing structural and functional plankton responses to carbendazim toxicity
    Slijkerman, D.M.E. ; Baird, D.J. ; Conrad, A. ; Jak, R.G. ; Straalen, N.M. van - \ 2004
    Environmental Toxicology and Chemistry 23 (2004)2. - ISSN 0730-7268 - p. 455 - 462.
    waterorganismen - zoöplankton - waterverontreiniging - toxiciteit - carbendazim - biotesten - daphnia magna - fungiciden - aquatische ecosystemen - ecotoxicologie - aquatic organisms - zooplankton - water pollution - toxicity - carbendazim - bioassays - daphnia magna - fungicides - aquatic ecosystems - ecotoxicology - postexposure feeding depression - fresh-water microcosms - daphnia-magna - fungicide carbendazim - oligotrophic lake - phytoplankton - impact - ecosystems - nutrients
    A model ecosystem experiment was conducted to investigate the ability of an in situ Daphnia magna feeding bioassay to assess impairment of ecosystem function. Animals were deployed in model ecosystems dosed with different concentrations of the fungicide carbendazim, and effects on the postexposure feeding rate of D. magna were compared with effects on zooplankton species richness (ecosystem structure) and development of phytoplankton biomass (ecosystem function). In the medium-dosed systems (21 ¿g/L), a structural change was observed within the zooplankton community, but no indirect effects on phytoplankton development were detected. It appears that at this treatment level, functional redundancy was sufficient to prevent functional impairment despite species loss. The feeding assay did not show any response at this concentration. In the high-dosed systems (221 ¿g/L), structural changes in the zooplankton community were accompanied by increased development of phytoplankton biomass. The feeding bioassay also showed a significant response at this concentration. At the high treatment level, species loss resulted in functional impairment, indicating that at this level, functional redundancy could not compensate for loss of individuals. The D. magna feeding bioassay matched well with the functional response (i.e., the indirect effects on phytoplankton) in the dosed systems but not with the more subtle effects on zooplankton community structure. These results lend positive support to the use of in situ feeding bioassays in combination with structural indices, such as species richness, to assess the effects of stress on ecosystem functioning in a direct way.
    Nutritional value of sediments for macroinvertebrate communities in shallow eutrophic waters
    Vos, J.H. de; Peeters, E.T.H.M. ; Gylstra, R. ; Kraak, M.H.S. ; Admiraal, W. - \ 2004
    Archiv für Hydrobiologie 161 (2004)4. - ISSN 0003-9136 - p. 469 - 487.
    waterkwaliteit - chironomus riparius - biotesten - oppervlaktewater - eutrofiëring - meren - nederland - waterbodems - aquatische ecosystemen - water quality - chironomus riparius - bioassays - surface water - eutrophication - lakes - netherlands - water bottoms - aquatic ecosystems - chironomid larvae - organic-matter - growth - detritivore - diptera
    The role of the nutritional quality of non-polluted soft-bottom sediments as a factor structuring in situ macroinvertebrate communities was studied in shallow eutrophic waters in The Netherlands. Sediments from clean sites were collected and analyzed for general characteristics (e.g. grain-size distribution) and nutritional value (e.g. C, N, P, polyunsaturated fatty acids). Also, macroinvertebrates were collected from these sediments and identified. In laboratory bioassays, Chironomus riparius midge larvae were exposed to these sediments to assess the nutritional value of each sediment. The abundance of detritivore taxa was positively associated with polyunsaturated fatty acids, bacterial fatty acids, pigments, and mineralization rate. These variables represent newly produced organic matter originating from the pelagic part of watersystems. Therefore, there seems to be a strong connection between the organic matter production in the pelagic part of watersystems and sediment food quality. The growth response of C. riparius larvae measured in the bioassay showed strong correlations with the abundance of detritivorous Chironomidae taxa in the sediment samples. Herbivorous and carnivorous taxa did not correlate with the bioassay results. Highest growth of C. riparius was observed in sediments with abundant detritivorous Chironomidae taxa and lowest growth was observed in sediments with taxa with other modes of feeding. Therefore, growth of C. riparius seems to effectively indicate the nutritional value of sediments for sediment bulk feeders. The use of bioassays with midge larvae permits evaluation of the importance of organic matter as a determinant of community structure without the confounding effects of other factors such as oxygen regime or stability of the substrate, which tend to covary with organic content. It is postulated that such non-food variables select the species that dominate sites. Yet, nutritional value determines the overall density of detritivores and, therefore, is concluded to be a major factor influencing faunal communities in shallow eutrophic waters
    Seasonal variation in plankton community responses of mesocosms dosed with pentachlorophenol
    Willis, K.J. ; Brink, P.J. van den; Green, J.D. - \ 2004
    Ecotoxicology 13 (2004)7. - ISSN 0963-9292 - p. 707 - 720.
    zooplankton community - ceriodaphnia-dubia - toxicity - insecticide - ponds - phytoplankton - microcosms - bioassays - recovery - systems
    Seasonal variations in plankton community response to pentachlorophenol (PCP) were studied in four mesocosm experiments using enclosures in a small lake. The mesocosms (860 l) were dosed with single applications of technical grade PCP (0, 4, 10, 24, 36, 54, 81 and 121 mgrg/l PCP) and monitored for 20 days. Multivariate statistical analyses showed that plankton community taxonomic composition varied with season. In winter and spring, communities were most stable in time; species diversity and abundance were lowest in winter. Seasonally, the communities varied little with respect to the dominant species, which were the copepod Calamoecia lucasi, the alga Peridinium sp. and the rotifer Ascomorpha ovalis. The direct effects of the PCP additions varied little between seasons, but indirect effects were evident at lower treatment levels in autumn. Indirect effects were not evident in winter. Minor variations in plankton community responses to PCP with season were apparent in the following order of decreasing sensitivity; autumn ge winter/spring ge summer. At the species level, C. lucasi showed the largest response. The responses observed were greatest in autumn, with decreased abundance at PCP concentrations ge 24 mgrg/l. In the other seasons, effects were observed at levels of 54 or 81mgrg/l and higher. Ascomorpha ovalis was the most responding rotifer in winter and spring, whereas Anuraeopsis fissa responded more strongly in autumn and summer. The dinoflagellate alga Peridinium sp. had the largest negative response in all but winter, when Dinobryon cylindricum did. Cryptomonas sp. responded positively to PCP in all seasons, increasing in abundance in the highest treatments, possibly due to reduced grazing pressure, reduced competition, or increased decomposition. The plankton community no-observed effect-concentration (NOEC) was 24–36 mgrg/l PCP. Results reported here suggest that the Australian and New Zealand water quality guideline values for PCP are sufficient to protect plankton communities against adverse effects.
    Intra- and interlaboratory calibration of the DR Calux bioassay for the analysis of dioxins and dioxin-like chemicals in sediments
    Besselink, H.T. ; Schipper, C.A. ; Klamer, H. ; Leonards, P.E.G. ; Verhaar, H. ; Felzel, E. ; Murk, A.J. ; Thain, J. ; Hosoe, K. ; Schoeters, G. ; Legler, J. ; Brouwer, A. - \ 2004
    Environmental Toxicology and Chemistry 23 (2004)12. - ISSN 0730-7268 - p. 2781 - 2789.
    dioxinen - toxiciteit - biotesten - waterbodems - ecotoxicologie - dioxins - toxicity - bioassays - water bottoms - ecotoxicology - equivalency factors tefs - in-vitro bioassay - round-robin - pcbs - pcdds - pcdfs - support - water - assay
    In the Fourth National Policy Document on Water Management in the Netherlands, it is defined that in 2003, in addition to the assessment of chemical substances, special guidelines for the assessment of dredged material should be recorded. The assessment of dredged material is based on integrated chemical and biological effect measurements. Among others, the DR CALUX® (dioxin responsive–chemically activated luciferase expression) bioassay has tentatively been recommended for inclusion in the dredged material assessment. To ensure the reliability of this bioassay, an intra- and interlaboratory validation study, or ring test, was performed, organized by the Dutch National Institute for Coastal and Marine Management (RIKZ) in cooperation with BioDetection Systems BV (BDS)
    In the Fourth National Policy Document on Water Management in the Netherlands [1], it is defined that in 2003, in addition to the assessment of chemical substances, special guidelines for the assessment of dredged material should be recorded. The assessment of dredged material is based on integrated chemical and biological effect measurements. Among others, the DR CALUX(R) (dioxin responsive-chemically activated luciferase expression) bioassay has tentatively been recommended for inclusion in the dredged material assessment. To ensure the reliability of this bioassay, an intra- and interlaboratory validation study, or ring test, was performed, organized by the Dutch National Institute for Coastal and Marine Management (RIKZ) in cooperation with BioDetection Systems BV (BDS). The intralaboratory repeatability and reproducibility and the limit of detection (LOD) and quantification (LOQ) of the DR CALUX bioassay were determined by analyzing sediment extracts and dimethyl sulfoxide (DMSO) blanks. The highest observed repeatability was found to be 24.1%, whereas the highest observed reproducibility was calculated to be 19.9%. Based on the obtained results, the LOD and LOQ to be applied for the bioassay are 0.3 and 1.0 pM, respectively. The interlaboratory calibration study was divided into three phases, starting with analyzing pure chemicals. During the second phase, sediment extracts were analyzed, whereas in the third phase, whole sediments had to be extracted, cleaned, and analyzed. The average interlaboratory repeatability increased from 14.6% for the analysis of pure compound to 26.1% for the analysis of whole matrix. A similar increase in reproducibility with increasing complexity of handlings was observed with the interlaboratory reproducibility of 6.5% for pure compound and 27.9% for whole matrix. The results of this study are intended as a starting point for implementing the integrated chemical-biological assessment strategy and for systematic monitoring of dredged materials and related materials in the coming years.
    The effect of taxonomic resolution on the assessment of ecological water quality classes
    Schmidt-Kloiber, A. ; Nijboer, R.C. - \ 2004
    Hydrobiologia 516 (2004)1-3. - ISSN 0018-8158 - p. 269 - 283.
    waterkwaliteit - taxonomie - ecologie - benthos - waterorganismen - biotesten - waterlopen - hydrologie - rivieren - richtlijnen (directives) - eu regelingen - europa - kaderrichtlijn water - biologische monitoring - ecologische beoordeling - water quality - taxonomy - ecology - benthos - aquatic organisms - bioassays - streams - hydrology - rivers - directives - eu regulations - europe - water framework directive - biomonitoring - ecological assessment - macroinvertebrate communities - benthic macroinvertebrates - biological integrity - resource-management - predictive models - biotic index - river - bioassessment - classification - identification
    Within the ecological assessment of running waters based on benthic macroinvertebrates different levels of taxonomic resolution (species, genus, family and higher) are in use. Although assessment systems are often developed with detailed data on species level, water managers and other end-users could like to use data on higher taxonomic levels to assess the ecological quality of a water body because of limited human or money resources. The question that arises is, if an assessment system built with species level data is also applicable using data with a higher taxonomic resolution. Within the AQEM project a multimetric assessment system was developed to evaluate the ecological quality classes (from bad (1) to high (5) ecological quality) of different stream types throughout Europe. The present study focuses on the question whether the resulting water quality class changes using the AQEM Assessment Software (AAS) with different taxonomic resolutions and if yes, how large the deviations of ecological quality classes from the original classes are and if the deviations are unidirectional. For analyses data from four Austrian and two Dutch stream types were used. It is demonstrated that the assignment of a site to an ecological quality class may change if different taxonomic levels are used. Deviations in both directions (higher/lower ecological quality class) were observed. In most cases the divergence was only one ecological quality class, but also larger deviations occasionally occurred. The causes of changes in the assessment were investigated by separately looking into the underlying metrics of the multimetric system. Some of the evaluated metrics rely on autecological information on species level and are simply not applicable on higher taxonomic levels. Other metrics worked on higher taxonomic levels as well and showed more or less good distinctions between ecological quality classes. It is concluded that the AQEM Assessment Software is not applicable if data on higher taxonomic levels are used. As the deviations were not unidirectional and ranged from one to three ecological quality classes, it is not possible to include a correction factor for using the software with higher taxonomic resolution data.
    Toxicological profiling of sediments with in vitro mechanisms-based bioassays for endocrine disruption
    Houtman, C.J. ; Cenijn, P.H. ; Hamers, T. ; Lamoree, M.H. ; Legler, J. ; Murk, A.J. ; Brouwer, A. - \ 2004
    Environmental Toxicology and Chemistry 23 (2004)1. - ISSN 0730-7268 - p. 32 - 40.
    biotesten - sediment - toxiciteit - hormonen - estuaria - rivieren - nederland - hormoonverstoorders - waterbodems - ecotoxicologie - rijn - maas - bioassays - sediment - toxicity - hormones - estuaries - rivers - netherlands - endocrine disruptors - water bottoms - ecotoxicology - river rhine - river meuse - reporter gene assays - estrogenic activity - aromatic-hydrocarbons - human transthyretin - expression assays - toxic potency - extracts - chemicals - exposure - wildlife
    In vitro bioassays are valuable tools for screening environmental samples for the presence of bioactive (e.g., endocrine-disrupting) compounds. They can be used to direct chemical analysis of active compounds in toxicity identification and evaluation (TIE) approaches. In the present study, five in vitro bioassays were used to profile toxic potencies in sediments, with emphasis on endocrine disruption. Nonpolar total and acid-treated stable extracts of sediments from 15 locations in the Rhine Meuse estuary area in The Netherlands were assessed. Dioxin-like and estrogenic activities (using dioxin-responsive chemical-activated luciferase gene expression [DR-CALUX] and estrogen-responsive chemical-activated luciferase gene expression [ER-CALUX] assays) as well as genotoxicity (UMU test) and nonspecific toxic potency (Vibrio fischeri assay) were observed in sediment extracts. For the first time, to our knowledge, in vitro displacement of thyroid hormone thyroxine (T4) from the thyroid hormone transport protein thransthyretin by sediment extracts was observed, indicating the presence of compounds potentially able to disrupt T4 plasma transport processes. Antiestrogenic activity was also observed in sediment. The present study showed the occurrence of endocrine-disrupting potencies in sediments from the Dutch delta and the suitability of the ER- and DR-CALUX bioassays to direct endocrine-disruption TIE studies.
    A simple method for analysing the effects of algae on the growth of Lemna and preventing algal growth in duckweed bioassays
    Szabo, S. ; Roijackers, R.M.M. ; Scheffer, M. - \ 2003
    Archiv für Hydrobiologie 157 (2003)4. - ISSN 0003-9136 - p. 567 - 575.
    schadelijke waterplanten - toxicologie - biotesten - ecotoxicologie - aquatic weeds - toxicology - bioassays - ecotoxicology - fresh-water macrophytes - common duckweed - waste-water - toxicity - ph
    A simple novel method for indoor culture experiments with small floating water plants, such as Lemnaceae, is described. Experiments demonstrate that the method allows for longer lasting culture experiments with Lemna, avoiding algal growth and self-shading of fronds by overcrowding. This is achieved by enclosing the Lemna fronds in tubes, which are replaced during growth by tubes of increasing diameter. The RGR of Lemna reached optimal values (RGR > 0.3 day-1) when not hampered by algal growth. In competition experiments with algae growing outside the tubes and Lemna inside the tubes, the growth of the fronds decreased dramatically; chlorophyll content of the fronds was 91-97% less and RGR 29-55 % less. This method allows for multifactorial experiments, handling up to 100 experimental units per researcher. This paves the road to competition experiments among and between water plants for light, nutrients and space
    ENOD40 affects phytohormone cross-talk
    Ruttink, T. - \ 2003
    Wageningen University. Promotor(en): Ton Bisseling, co-promotor(en): Henk Franssen. - [S.l.] : S.n. - ISBN 9789058089793 - 136
    plantengroeiregulatoren - knobbeltjes - nodulinen - rhizobium - ethyleen - auxinen - cytokininen - organogenese - genetische regulatie - biotesten - transcriptie - signaaltransductie - plant growth regulators - nodules - nodulins - rhizobium - ethylene - auxins - cytokinins - organogenesis - genetic regulation - bioassays - transcription - signal transduction
    Only a small number ofphytohormonesare sufficient to regulate virtually every aspect of plant growth and development. Hence, adequate communication betweenphytohormonesis important to coordinate cellular processes during development. In this thesis we show that the plant gene ENOD40 plays a role in the communication betweenphytohormonesignaling pathways.

    Mainly on the basis of its complex expression patterns, it has been suggested that ENOD40 could affect thephytohormonestatus of cells, thus participating in regulation of plant growth and development but direct evidence was lacking. We have developed bioassays to study the function of ENOD40 in relation tophytohormonesignaling, using tobacco BY-2 cell-cultures. In these filamentous cell suspensions, quantification of cell-growth and cell division is straightforward and these morphological growth parameters can be used to monitor responses tophytohormones. In wild-type cells that have no or very low levels of ENOD40 expression, both processes are by-en-large independent of each other. By quantifying the parameters cell-elongation growth and cell division frequency under variousphytohormoneregimes in transgenic, 35S: NtENOD40 containing, tobacco BY-2 cell suspensions, we showed that the relative rates of both cellular processes become coupled byoverexpressionof ENOD40 . Since elongation growth is regulated by ethylene and cell division by thecytokinin/auxinratio, our data indicate that ENOD40 is involved in cross-talk between ethylene,auxinandcytokinin.

    Furthermore, we present an overview of ENOD40 expression patterns and analyze the structure of ENOD40 transcripts. The transcripts are characterized by two short conserved nucleotide sequence regions, which both contain biological activity in the bio-assay, and one of the two regions encodes a remarkably shortoligopeptide. 

    In conclusion, the observation that ENOD40 affectsphytohormoneresponses in BY-2 cells is consistent withspatio-temporal ENOD40 expression patterns, which correlates with developmental stages involving the activity ofphytohormones. We propose that coupling between cell division, cell growth and cell differentiation may be achieved by transient and local expression of plant factors like ENOD40 that are involved inphytohormonecross-talk pathways. The coupling of hormone responses may be crucial to many developmental programs, and this may explain the complexity of ENOD40 expression patterns and the variety of tissues with which ENOD40 expression is associated in different plant species.

    Effecten van hormoonverstorende stoffen op kikkers
    Lee-de Groot, M.B.E. ; Brink, N.W. van den; Hout, A. van der; Bie, P.A.F. de; Stumpel, A.H.P. ; Bosveld, A.T.C. - \ 2003
    Wageningen : Alterra (Alterra-rapport ) - 77
    amphibia - estradiol - dioxinen - toxicologie - voortplantingsorganen - mortaliteit - hormonen - biotesten - ecotoxicologie - hormoonverstoorders - amphibia - estradiol - dioxins - toxicology - reproductive organs - mortality - hormones - bioassays - ecotoxicology - endocrine disruptors
    Omdat de ontwikkeling van amfibieën sterk hormoon-gereguleerd is, is onderzocht in hoeverre de kikker een geschikte indicator is voor hormoonverstorende stoffen in het milieu. Hiertoe zijn in het laboratorium blootstellingstudies uitgevoerd met kikkerlarven en volwassen Rana kikkers, welke algemeen in Nederland voorkomen. Onderzocht is in hoeverre oestradiol (E2) en tetrachloordibenzo-p-dioxine (TCDD) de ontwikkeling, overleving, lichaams- en orgaangewichten, geslachtsorganen en -hormonen, en specifieke cytochroom P450 enzymen beïnvloeden. Ook is de onderlinge samenhang van deze ettectparameters bestudeerd. In een in-situ veldstudie zijn de overleving en ontwikkeling van larven van Rana Kikkers, die zijn uitgezet in de sterk verontreinigde Volgermeerpolder en een niet-verontreinigde referentielocatie, beschouwd. Naast dit alles zijn juveniele Rana kikkers gevangen uit beide locaties, waarin interne concentraties dioxine-achtige stoffen en activiteiten van specifieke cytochroom P450 enzymen zijn bepaald.
    Explorative research into quality of slurry manure from dairy farms with different feeding strategies
    Reijs, J.W. ; Meijer, W.H. ; Bakker, E.J. ; Lantinga, E.A. - \ 2003
    Netherlands Journal of Agricultural Science 51 (2003)1-2. - ISSN 0028-2928 - p. 67 - 89.
    rundveemest - rundveedrijfmest - stikstof - diervoedering - grasbestand - fytotoxiciteit - grassen - klavers - biotesten - melkveehouderij - cattle manure - cattle slurry - nitrogen - animal feeding - herbage - phytotoxicity - grasses - clovers - bioassays - dairy farming - cress lepidium-sativum - seed-germination - sewage-sludge - cattle feces - growth - mineralization - decomposition - netherlands - deterrents
    To assess cattle slurry manure quality in relation to feeding strategy, a field experiment and a bio-assay were carried out with slurries from four dairy farming systems that used diets differing in protein content and digestibility. Several quality aspects were evaluated. In the field experiment the effects of slurry manure type on herbage rejection by grazing heifers and herbage yield on undisturbed plots under cages were studied for a grass monoculture and a grass/clover mixture. The bio-assay, consisting of a cress (Lepidium sativum L.) seed germination test, was used to study differences in phytotoxicity between the slurry types. After five weeks of undisturbed growth at equal amounts of applied inorganic nitrogen (N), the herbage yields differed statistically for the different slurries. This was probably due to immobilization of N in the case of the two slurries from farming systems in which straw was fed and used as bedding material. Herbage rejection by grazing animals was significantly shown for all slurry types and was significantly and positively correlated with the NH3/NH4 +-N content of the slurry. The slurries showed large differences in phytotoxicity to seeds and seedlings in the bio-assay. Ammonia and electric conductivity appeared to be the most important slurry parameters with inhibiting effects. The slurries with a high C/N ratio showed lowest phytotoxicity. Phytotoxicity in the cress seed germination test did not account for reduced herbage yields in the field experiment. On the contrary, when the slurries were ranked according to their phytotoxicity the order was the same as the ranking on the basis of undisturbed herbage yield. It was concluded that there is a need for other laboratory tests that show greater resemblance with what is observed in the field to assess slurry quality.
    Responses in sediment bioassays used in the Netherlands: can observed toxicity be explained by routinely monitored priority pollutants?
    Lahr, J. ; Maas-Diepeveen, J.L. ; Stuijfzand, S.C. ; Leonards, P.E.G. ; Drueke, J.M. ; Luecker, S. ; Espeldoorn, A. - \ 2003
    Water Research 37 (2003)8. - ISSN 0043-1354 - p. 1691 - 1710.
    biotesten - sediment - toxiciteit - monitoring - verontreinigende stoffen - delta's - nederland - waterverontreiniging - waterbodems - rijn - maas - bioassays - sediment - toxicity - monitoring - pollutants - deltas - netherlands - water pollution - water bottoms - river rhine - river meuse - quality criteria - daphnia-magna - rhine delta - water - tests - microcontaminants - fractionation - crustacea - chemicals - organisms
    In order to identify the cause of toxicity in sediments and suspended matter, a large number of samples with different degrees of contamination was taken at various locations in The Netherlands. Standard acute bioassays were carried out with the bacterium Vibrio fischeri, the rotifer Brachionus calyciflorus and the anostracan Thamnocephalus platyurus. Chronic standard tests were performed using the water flea Daphnia magna and larvae of the midge Chironomus riparius. Some novel bioassays were performed as well. Most toxic effects observed in standard bioassays with sediments from polluted sediments (class 3 and 4 on a scale of 0¿4 according to the Dutch criteria) could be partly explained by toxic concentrations of known persistent priority pollutants, mainly heavy metals and occasionally polycyclic aromatic hydrocarbons. In some of the samples, ammonia toxicity was a confounding factor during testing. Suspended matter from the Meuse river at Eijsden, which may be considered as `new' sediment (pollution class 2), was moderately to highly toxic in almost all bioassays. This could have been associated with a combination of heavy metals, PAHs and ammonia. At two locations from the Lake IJssel area with no apparent persistent pollution, moderate and strong effects were nonetheless observed in invertebrate tests. This might have been due to agricultural run-off of pesticides, which are not routinely measured in sediments. A few effects on V. fischeri in canals and a small stream could not be explained with standard chemical analysis, but seemed associated with the outlets of sewage water treatment plants and industrial effluents. Additional chemical analysis of pore water samples from five selected sediments yielded more identified substances such as phtalates, decanes, cosanes and fragrances, but it was estimated that their contribution to the effects observed on V. fischeri, D. magna and C. riparius was negligible.
    Statistical analysis of sediment toxicity by additive monotone regression splines
    Boer, W.J. de; Besten, P.J. den; Braak, C.J.F. ter - \ 2002
    Ecotoxicology 11 (2002)6. - ISSN 0963-9292 - p. 435 - 450.
    toxicologie - daphnia - biotesten - waterbodems - daphnia - toxicology - bioassays - water bottoms - soil
    Modeling nonlinearity and thresholds in dose-effect relations is a major challenge, particularly in noisy data sets. Here we show the utility of nonlinear regression with additive monotone regression splines. These splines lead almost automatically to the estimation of thresholds. We applied this novel method to explore the relation between the toxicity of aquatic sediments, as observed in bioassays with Daphnia magna, Chironomus riparius and Vibrio fischeri, and the degree of contamination of the sediments. Despite the low signal-to-noise ratio in the data, some interesting thresholds and (non)linear effects were found. The method has added value compared to the linear multivariate methods applied earlier to these data. Percentages of explained variance remained low, but could be doubled by diminishing the effect of local variability
    Detection of estrogenic potency in wastewater and surface water with three in vitro bioassays
    Murk, A.J. ; Legler, J. ; Lipzig, M.M.H. van; Meerman, J.H.N. ; Belfroid, A.C. ; Spenkelink, A. ; Burg, B. van der; Rijs, G.B.J. ; Vethaak, D. - \ 2002
    Environmental Toxicology and Chemistry 21 (2002)1. - ISSN 0730-7268 - p. 16 - 23.
    oppervlaktewater - afvalwater - oestrogenen - biotesten - hormonen - surface water - waste water - oestrogens - hormones - bioassays
    A study was performed to optimize sample preparation and application of three in vitro assays for measuring estrogenic potency in environmental extracts. The three assays applied were an estrogen receptor (ER)-binding assay and two reporter gene effect assays: a yeast estrogen screen (YES) and the ER-mediated chemically activated luciferase gene expression (ER-CALUX) assay. All assays were able to detect estrogenicity, but the amounts of material needed for the assays differed greatly between the three assays (ER-binding assay ≫ YES > ER-CALUX). In addition, in the ER-binding assay, both agonists and antagonists give an estrogenic response, resulting in higher estradiol equivalency (EEQ) levels than both the ER-CALUX and the YES assay for the same samples. The EEQs found in wastewater treatment plants (WTPs) with the ER-CALUX assay were in the range of 4 to 440 and 0.11 to 59 pmol/L for influent and effluent, respectively. Water extracts from four large rivers had levels ranging from 0.25 to 1.72 pmol/L. Extracts from suspended matter and sludge contained estrogenic potency of 0.26 to 2.49 and 1.6 to 41 pmol EEQ/g dry weight, respectively. In WTPs, the average reduction of estrogenic potency in effluent compared to influent was 90 to 95% in municipal WTPs and about 50% in industrial WTPs. In influent, 30% of the ER-CALUX activity could not be explained by the calculated potencies based on chemical analysis of a number of known (xeno)estrogens; in effluent the unexplained fraction was 80%. These first results of analyzing estrogenic potency in WTP water and surface water in The Netherlands indicate that further studies are warranted to investigate the actual risks for aquatic systems.
    Validatie en toepassing van de CALUX-bioassay voor diervoeders
    Traag, W.A. ; Hoogenboom, L.A.P. - \ 2001
    Wageningen : RIKILT (Rapport / Rijks-Kwaliteitsinstituut voor land- en tuinbouwprodukten RIKILT 2001.004) - 12
    biotesten - dioxinen - voer - citruspulp - screenen - bioassays - dioxins - feeds - citrus pulp - screening
    Schadelijke stoffen in scholekstereieren; responsmetingen in bioassays ter bepaling van risico's van contaminanten in eieren van scholeksters uit het Zeehavenkanaal
    Roode, D.F. de; Crum, S.J.H. ; Rouhani Rankouhi, T. ; Sanderson, T. ; Bosveld, A.T.C. - \ 2001
    Wageningen : Alterra (Alterra-rapport 402) - 37
    vogels - toxische stoffen - verontreinigende stoffen - toxiciteit - hexachloorbenzeen - biotesten - bursa van fabricius - embryo's - waadvogels - waterbodems - broedvogels - ecotoxicologie - milieuverontreiniging - scholekster - zeevogels - Groningen - Delfzijl - birds - toxic substances - pollutants - toxicity - hexachlorobenzene - bioassays - bursa fabricii - embryos - waders - water bottoms
    In het verleden zijn door het RIKZ in het Zeehavenkanaal te Delfzijl hoge hexachloorbenzeengehalten gemeten. Na sanering voldeed de onderwaterbodem voor hexachloorbenzeen echter nog steeds niet aan de normen voor het baggerbeheer. In eieren van scholeksters die foerageren in het met hexachloorbenzeen verontreinigde gebied, zijn ook verhoogde concentraties gemeten. De vraag is of deze verhoogde concentraties hexachloorbenzeen en eventuele andere verontreinigingen nadelige effecten hebben op de scholeksters. Uit het onderzoek waarvan de resultaten in dit rapport beschreven staan, blijkt dat de in de eieren aanwezige stoffen in staat zijn om effecten bij vogels te veroorzaken.
    Landbouwbestrijdingsmiddelen: waarom wijken toelatingsnormen af van MTR's
    Appelman, J. ; Brock, T.C.M. - \ 2001
    H2O : tijdschrift voor watervoorziening en afvalwaterbehandeling 34 (2001)21. - ISSN 0166-8439 - p. 25 - 27.
    pesticiden - landbouw - waterkwaliteit - waterverontreiniging - verontreinigingsbeheersing - normen - beleid - overheidsbeleid - oppervlaktewater - risico - risicoschatting - milieueffect - hydrobiologie - aquatische gemeenschappen - zoetwaterecologie - doseringseffecten - biotesten - toxiciteit - toxicologie - waterorganismen - ecotoxicologie - ecohydrologie - aquatische ecosystemen - aquatische ecologie - bestrijdingsmiddelen - milieu - pesticides - agriculture - water quality - water pollution - pollution control - standards - policy - government policy - surface water - risk - risk assessment - environmental impact - hydrobiology - aquatic communities - freshwater ecology - dosage effects - bioassays - toxicity - toxicology - aquatic organisms - ecotoxicology - ecohydrology - aquatic ecosystems
    Uitleg over de totstandkoming van de door het College voor de Toelating van Bestrijdingsmiddelen (CTB) gehanteerde normen voor het bepalen van de risico's van bestrijdingsmiddelen voor het aquatisch ecosysteem, en hoe deze toelatingsnormen zich verhouden tot de in het waterkwaliteitsbeleid gehanteerde maximaal toelaatbare risiconiveaus (MTR's). Beide normen worden vergeleken met de waargenomen effecten van stoffen (insecticiden, herbiciden, fungiciden) in veldexperimenten. Daaruit blijkt dat de CTB-normen voldoende bescherming bieden voor waterorganismen
    Benthic macroinvertebrates and multiple stressors : quantification of the effects of multiple stressors in field, laboratory and model settings
    Peeters, E.T.H.M. - \ 2001
    Wageningen University. Promotor(en): M. Scheffer; A.A. Koelmans. - S.l. : S.n. - ISBN 9789058085108 - 168
    ongewervelde dieren - biotesten - modellen - benthos - milieufactoren - besmetters - toxische stoffen - stressfactoren - ecologie - aquatische ecosystemen - ecotoxicologie - invertebrates - bioassays - models - benthos - environmental factors - contaminants - toxic substances - stress factors - ecology - aquatic ecosystems - ecotoxicology

    Organisms are always exposed to several simultaneously operating stressors in nature. It appears that the combined effects of multiple stressors cannot be understood as a simple product of their individual effects. To understand how multiple stressors affect the composition and functioning of ecosystems it is necessary to know their quantitative contributions but also to explore their interactions. The central theme of this thesis is the quantification of the combined effects of multiple stressors on benthic aquatic macroinvertebrates and their communities. The statistical analyses of data sets in this thesis demonstrate that effects of multiple stressors in field situation can be quantified and that the benthic macroinvertebrate communities are affected by micropollutants. Furthermore, the modeling and laboratory studies show that the type of interaction between stressors can be analyzed and also that the effect of a certain stressor depends on the impact of all other stressors. Energy budgets and scope for growth seem powerful tools for improving the knowledge on the distribution and abundance of organisms. Finally, this thesis provides a foundation for differentiated standard setting.

    Evaluation of bioassays versus contaminant concentrations in explaining the macroinvertebrate community structure in the Rhine-Meuse delta, the Netherlands
    Peeters, E.T.H.M. ; Dewitte, A. ; Koelmans, A.A. ; Velden, J.A. van der; Besten, P.J. den - \ 2001
    Environmental Toxicology and Chemistry 20 (2001)12. - ISSN 0730-7268 - p. 2883 - 2891.
    rivieren - delta's - waterinvertebraten - biotesten - toxiciteit - rijn - maas - rivers - deltas - aquatic invertebrates - bioassays - toxicity - river rhine - river meuse
    It is often assumed that bioassays are better descriptors of sediment toxicity than toxicant concentrations and that ecological factors are more important than toxicants in structuring macroinvertebrate communities. In the period 1992 to 1995, data were collected in the enclosed Rhine-Meuse delta, The Netherlands, on macroinvertebrates, sediment toxicity, sediment contaminant concentrations, and ecological factors. The effect of various groups of pollutants (polycyclic aromatic hydrocarbons, trace metals, oil, polychlorinated biphenyls) and of ecological variables on the structure of the macroinvertebrate community were quantified, Ecological factors explained 17.3␘f the macroinvertebrate variation, while contaminants explained 13.8ÐAnother 14.7 as explained by the covariation between ecological variables and contaminants. Polycyclic aromatic hydrocarbons explained a larger part of the variation than trace metals. The contributions of oil and polychlorinated biphenyls were small but significant. Elevated contaminant concentrations were significantly associated with differences in the macroinvertebrate food web structure. The response in bioassays (Vibrio fischeri, Daphnia magna, Chironomus riparius) was susceptible to certain contaminants but also to certain ecological factors. There was a weak correlation between in situ species composition and bioassays; 1.9␘f in situ macroinvertebrate variation was explained by the bioassay responses. This seems to contradict the validity of using bioassays for a system-oriented risk assessment. Possible reasons for this discrepancy might be the manipulations of the sediment before the test and a higher pollutant tolerance of the in situ macroinvertebrates. Thus, macroinvertebrate field surveys and laboratory bioassays yield different types of information on ecotoxicological effects, and both are recommended in sediment risk assessment procedures.
    Veldbioassays : ontwikkeling van een richtlijn voor veldbioassays met watervlooien en waterplanten voor het aantonen van bestrijdingsmiddelen in oppervlaktewater
    Jong, F.M.W. de; Deneer, J.W. ; Tamis, W.L.M. - \ 2000
    Leiden : Centrum voor Milieukunde, Universiteit Leiden (CML rapport 150 / Alterra-rapport 61) - 89
    pesticiden - biotesten - toxicologie - waterplanten - nederland - waterverontreiniging - daphnia - waterkwaliteit - meting - biologische monitoring - water pollution - water quality - pesticides - measurement - bioassays - toxicology - daphnia - aquatic plants - netherlands - biomonitoring
    Richtlijn voor de selectie en de uitvoering van veldbioassays met watervlooien en waterplanten voor het aantonen van bestrijdingsmiddelen in oppervlaktewater
    Jong, F.M.W. de; Deneer, J.W. ; Tamis, W.L.M. - \ 2000
    S.n. - 24
    waterverontreiniging - waterkwaliteit - pesticiden - biotesten - daphnia - waterplanten - nederland - biologische monitoring - water pollution - water quality - pesticides - bioassays - daphnia - aquatic plants - netherlands - biomonitoring
    Haalbare productkwaliteit en restrisico's bij extensieve landfarming van baggerspecies
    Harmsen, J. ; Toorn, A. van den; Dijk-Hooyer, O.M. van; Wieggers, H.J.J. ; Zweers, A.J. - \ 2000
    Wageningen : Alterra (Alterra-rapport 44) - 88
    sediment - ontginning - bioremediëring - bagger - verontreinigende stoffen - mineraaloliën - biotesten - biodegradatie - polycyclische koolwaterstoffen - nederland - sludge farming - sediment - reclamation - bioremediation - dredgings - pollutants - mineral oils - bioassays - biodegradation - polycyclic hydrocarbons - netherlands - sludge farming
    In deze studie zijn de risico's onderzocht van vier verschillende sedimenten die al gedurende vier tot acht jaar waren gereinigd met behulp van intensieve en extensieve landfarming. De biologisch beschikbare fracties zijn vastgesteld met chemische en fysische tests. Ecologische risico's zijn onderzocht met biotests en een bioaccumulatietoets. De resultaten zijn vergeleken met de chemische samenstelling en gegevens verkregen op de landfarm Kreekraksluizen. In de partiële extractie konden drie verontreinigingsfracties worden onderscheiden, namelijk snel, langzaam en zeer langzaam desorberend. Deze fracties konden in verband worden gebracht met de resultaten van biotests, bioaccumulatie en de biologische afbraak op de landfarm. De gemeten biologische beschikbaarheid geeft daarom mogelijkheden tot sturing van de biologische afbraak en inzicht in risico's op een landfarm.
    Ecologische schade bij verontreinigde locaties?; doorwerking van BEVER in de bepaling van de ecologische bodemkwaliteit
    Postma, J. ; Eijsackers, H.J.P. ; Faber, J.H. ; Rutgers, M. ; Guchte, C. van de - \ 2000
    Bodem 10 (2000)1. - ISSN 0925-1650 - p. 9 - 9.
    bodem - volksgezondheidsbevordering - decontaminatie - schoonmaken - bodemverontreiniging - bodemgiftigheid - ecologie - milieu - milieueffect - milieutoets - schade - risicoschatting - biotesten - bodembiologie - landgebruik - milieueffectrapportage - ecotoxicologie - bioaccumulatie - soil - sanitation - decontamination - cleaning - soil pollution - soil toxicity - ecology - environment - environmental impact - environmental assessment - damage - risk assessment - bioassays - soil biology - land use - environmental impact reporting - ecotoxicology - bioaccumulation
    Uitleg over BLER, een basisbenadering voor een locatiespecifieke ecologische risicobeoordeling, voor een breed spectrum van bodemgebruiksvormen. Dit raamwerk voor een functiegerichte aanpak van bodemsanering is ontwikkeld in het kader ven de beleidsvernieuwing bodemsanering (BEVER)
    Bioassays en chemische metingen, is er een relatie?; multivariate analyse van chemische en biologische waarnemingen aan sedimenten van de Waddenzee en het Zeehavenkanaal
    Brink, P.J. van den; Kater, B.J. - \ 2000
    Wageningen : Alterra (Alterra-rapport 186) - 65
    waterverontreiniging - biotesten - sediment - multivariate analyse - ecotoxicologie - aquatische ecosystemen - waddenzee - waterbodems - water pollution - bioassays - sediment - multivariate analysis - ecotoxicology - aquatic ecosystems - water bottoms - wadden sea
    Dit rapport beschrijft de resultaten van de multivariatieanalyse van twee onderzoeken uitgevoerd door het Rijksinstituut voor Kust en Zee. In het Waddenonderzoek zijn sedimenten van zestien plaatsen in de Waddenzee zowel chemisch als biologisch beoordeeld met behulp van chemische metingen en een aantal laboratoriumbiotests in vitro en in vivo. De gegevensset van de Waddenzee is verzameld om na te gaan of waargenomen effecten in de biotests gerelateerd zijn aan de chemische karakteristieken, en welke gebieden in de Waddenzee als referentiegebied gebruikt kunnen worden. In het Zeehavenkanaal zijn niet alleen biotests en chemische metingen uitgevoerd, maar is tevens de bioaccumulatie van verschillende verbindingen in de zager (Nereis virens) onderzocht.
    Application of 3 in vitro bioassays for oestrogenicity in waste water treatment plants and large rivers
    Murk, A.J. ; Belfroid, A.C. ; Meerman, J.H.N. ; Legler, J. ; Burg, B. van den; Schafer, A.J. ; Rijs, G.B.J. ; Vethaak, A.D. - \ 2000
    In: Endocrine disrupting compounds : Wildlife and human health risks, The Hague 1998 The Hague : - p. 38 - 43.
    afvalwaterbehandeling - biotesten - oestrogenen - oppervlaktewater - rivieren - hormonen - zuiveringsinstallaties - waste water treatment - surface water - rivers - bioassays - oestrogens - hormones - purification plants
    Development of an in vivo assay for oestrogenic potency using transgenic zebrafish
    Legler, J. ; Broekhof, J. ; Brouwer, A. ; Murk, A.J. ; Saag, P. van der; Vethaak, A.D. ; Burg, B. van der - \ 2000
    In: Endocrine Disrupting Compounds : Wildlife and human health risks, The Hague 1998 The Hague : - p. 109 - 112.
    transgene dieren - vissen - danio rerio - biotesten - oestrogeenreceptoren - reporter-genen - waterdieren - ecotoxicologie - transgenic animals - aquatic animals - fishes - bioassays - oestrogen receptors - reporter genes - ecotoxicology
    Ecology and biological control of Verticillium dahliae
    Soesanto, L. - \ 2000
    Agricultural University. Promotor(en): M.J. Jeger; A.J. Termorshuizen. - S.l. : S.n. - ISBN 9789058081926 - 120
    verticillium dahliae - plantenziekteverwekkende schimmels - plantenziekten - ecologie - biologische bestrijding - plantenziektebestrijding - talaromyces flavus - biotesten - arabidopsis thaliana - verticillium dahliae - plant pathogenic fungi - plant diseases - ecology - biological control - plant disease control - talaromyces flavus - bioassays - arabidopsis thaliana

    The dynamics of Verticillium dahliae , the causal agent of wilt disease in many crops including potato, cotton, and olive, were investigated. Its biological control with Talaromyces flavus with or without additional Pseudomonas fluorescens was attempted. Arabidopsis thaliana was selected as a bioassay plant for studying aspects of ecology and biological control of the pathogen because of its short life cycle and high sensitivity to the pathogen. The optimal temperature for production of microsclerotia, the survival structures of the pathogen, both in vitro and on A. thaliana was about 20°C. Microsclerotia incorporated in soil were exposed to a range of conditions of temperature and moisture and quantified on several sampling occasions. One day after incorporation, densities were low, these densities were even lower over the following 1-6 months, but subsequently densities increased. These changes were ascribed to changes in the level of soil mycostasis rather than death and new formation of microsclerotia. After application of T. flavus to fresh organic debris containing microsclerotia followed by a 3-wk incubation aboveground at 15 or 25°C the population density of T. flavus increased in soil, especially at 25°C. T. flavus significantly reduced the density of microsclerotia in soil, especially at 25°C, and delayed the development of senescence of A. thaliana at 15 and 25°C.

    It is concluded that above-ground application of T. flavus may lead to more consistent effects. The effect of P. fluorescens strain P60, originally isolated from a take-all decline field continuously grown to wheat, on V. dahliae was also studied. Strain P60, and two other isolates of P. fluorescens , inhibited the in vitro mycelial growth of 20 isolates of V. dahliae , reduced formation of microsclerotia both in vitro and on A. thaliana and they retarded senescence of A. thaliana to a rate like that of uninoculated plants.

    Biomarkers in Terrestrial Invertebrates For Ecotoxicological Soil Risk Assessment
    Kammenga, J.E. ; Dallinger, R. ; Donker, M.H. ; Köhler, H.R. ; Simonsen, V. ; Triebskorn, R. ; Weeks, J.M. - \ 2000
    Reviews of Environmental Contamination and Toxicology 164 (2000). - ISSN 0179-5953 - p. 93 - 147.
    bodeminvertebraten - biotesten - biologische indicatoren - indicatorsoorten - ecotoxicologie - biologische monitoring - soil invertebrates - bioassays - biological indicators - indicator species - ecotoxicology - biomonitoring
    Criteria voor de beoordeling van resultaten van bioassays
    Hendriks, J. ; Brock, T.C.M. ; Guchte, K. van de; Maas, H. ; Meent, D. van de; Schipper, C. ; Stronkhorst, J. ; Zwart, D. de - \ 1998
    Lelystad : RIZA - 16
    biotesten - biologische technieken - waterkwaliteit - oppervlaktewater - monitoring - normen - biologische monitoring - waterbodems - bioassays - biological techniques - water quality - surface water - standards - biomonitoring - water bottoms
    Isolation, identification, synthesis and bioassays of the sex pheromones of Symmetrischema tangolias and Scrobipalpuloides absoluta. Final report on project DGIS NL/90/86
    Griepink, F.C. ; Visser, J.H. - \ 1996
    Wageningen : Research Institute for Plant-Protection (IPO-DLO) - 24
    insectenplagen - sexferomonen - symmetrischema tangolias - scrobipalpula absoluta - geïntegreerde plagenbestrijding - biotesten - insect pests - sex pheromones - symmetrischema tangolias - scrobipalpula absoluta - integrated pest management - bioassays
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