Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

    Current refinement(s):

    Records 1 - 20 / 68

    • help
    • print

      Print search results

    • export

      Export search results

    Check title to add to marked list
    Guidance for the Prognostic Risk Assessment of Nanomaterials in Aquatic Ecosystems
    Koelmans, A.A. ; Diepens, N.J. ; Velzeboer, I. ; Besseling, E. ; Quik, J.T.K. - \ 2015
    Science of the Total Environment 535 (2015). - ISSN 0048-9697 - p. 141 - 149.
    engineered nanomaterials - tio2 nanoparticles - environmental fate - carbon nanotubes - manufactured nanoparticles - hediste-diversicolor - silver nanoparticles - scrobicularia-plana - cuo nanoparticles - fresh-water
    Our understanding of the environmental fate and effects of engineered nanomaterials (ENMs) is in a state of fast transition. Recent scientific developments open new and powerful perspectives to define a framework for the prognostic risk assessment of ENMs in aquatic ecosystems. This requires abandoning the reductionist's approach of mechanistic analysis on particle or cellular scales and calls for engineering solutions that deal with uncertainties by applying assessment factors and probabilistic approaches. An ecological risk assessment (ERA) framework for ENMs is similar to that for other classes of substances, in that it requires clear protection goals based on ecosystem services, evidence-based concepts that link exposure to effects, and a transparent tiered effect assessment. Here, we discuss approaches to assess exposure and effects of ENMs. This includes recent developments in ENP fate modeling that greatly expanded the potential of prognostic exposure assessments. For the effect assessment, we advise a cost-effective screening based on principles of read-across as a conservative first tier. The feasibility of using species sensitivity distributions as a higher tier option is discussed. Controlled model ecosystem field experiments are proposed as a highest experimental tier, and are required for the calibration of the lower tiers. An outlook to unify information from various tiers by experimental work, fate modeling, and effect modeling as cost-effective prognostic tools for the ERA of ENMs is provided.
    Comparison of endogenous loss and maintenance need for minerals in rainbow trout (Oncorhynchus mykiss) fed fishmeal or plant ingredient-based diets
    Antony Jesu Prabhu, P. ; Kaushik, S.J. ; Mariojouls, C. ; Surget, A. ; Fontagné-Dicharry, S. ; Schrama, J.W. ; Geurden, I. - \ 2015
    Fish Physiology and Biochemistry 41 (2015)1. - ISSN 0920-1742 - p. 243 - 253.
    salmon salmo-salar - true phosphorus digestibility - fingerling channel catfish - biliary copper excretion - juvenile chinook salmon - phytate soybean meals - atlantic salmon - magnesium requirement - potassium requirement - fresh-water
    Mineral needs as affected by changes in dietary protein and oil sources were studied in rainbow trout. Duplicate groups (n = 30 fish per replicate) of rainbow trout (initial BW: 37 g) were fed either a fish meal/fish oil-based (M) or a complete plant ingredient (V)-based diet at four graded ration (R) levels [apparent satiation (AS), R75, R50 and R25 % of AS]; one treatment group was maintained under starvation. The feeding trial lasted 12 weeks at a water temperature of 17 °C. Dietary intake, apparent digestibility and initial and final whole-body composition data were used to calculate mineral gain which was regressed against digestible mineral intake (both expressed as mg or µg kg-0.8 day-1). Starvation loss (SL), endogenous loss of fed fish (ELF, y-intercept at x = 0) and point of intake for zero balance (PZB, x-intercept at y = 0) were used as estimates of maintenance requirements. SL provided the lowest estimate, ELF provided the net requirement of a mineral for maintenance and PZB provided the digestible dietary intake required to meet maintenance (SL
    Managing the effects of multiple stressors on aquatic ecosystems under water scarcity
    Navarro-Ortega, A. ; Acuña, V. ; Bellin, A. ; Burek, P. ; Cassiani, G. ; Choukr-Allah, R. ; Dolédec, S. ; Elosegi, A. ; Ferrari, F. ; Ginebreda, A. ; Grathwohl, P. ; Jones, C. ; Ker Rault, P.A. ; Kok, K. ; Koundouri, P. ; Ludwig, R.P. ; Merz, R. ; Milacic, R. - \ 2015
    Science of the Total Environment 503-504 (2015). - ISSN 0048-9697 - p. 3 - 9.
    climate-change - fresh-water - mediterranean rivers - southern europe - management - scenarios - quality - systems
    Water scarcity is a serious environmental problem in many European regions, and will likely increase in the near future as a consequence of increased abstraction and climate change. Water scarcity exacerbates the effects of multiple stressors, and thus results in decreased water quality. It impacts river ecosystems, threatens the services they provide, and it will force managers and policy-makers to change their current practices. The EU-FP7 project GLOBAQUA aims at identifying the prevalence, interaction and linkages between stressors, and to assess their effects on the chemical and ecological status of freshwater ecosystems in order to improve water management practice and policies. GLOBAQUA assembles a multidisciplinary team of 21 European plus 2 non-European scientific institutions, as well as water authorities and river basin managers. The project includes experts in hydrology, chemistry, biology, geomorphology, modelling, socio-economics, governance science, knowledge brokerage, and policy advocacy. GLOBAQUA studies six river basins (Ebro, Adige, Sava, Evrotas, Anglian and Souss Massa) affected by water scarcity, and aims to answer the following questions: how does water scarcity interact with other existing stressors in the study river basins? How will these interactions change according to the different scenarios of future global change? Which will be the foreseeable consequences for river ecosystems? How will these in turn affect the services the ecosystems provide? How should management and policies be adapted to minimise the ecological, economic and societal consequences? These questions will be approached by combining data-mining, field- and laboratory-based research, and modelling. Here, we outline the general structure of the project and the activities to be conducted within the fourteen work-packages of GLOBAQUA.
    The impact of elevated water nitrite concentration on physiology, growth and feed intake of African catfish Clarias gariepinus (Burchell 1822)
    Roques, J.A.C. ; Schram, E. ; Spanings, T. ; Schaik, T. van; Abbink, W. ; Boerrigter, J. ; Vries, P. de; Vis, J.W. van de; Flik, G. - \ 2015
    Aquaculture Research 46 (2015)6. - ISSN 1355-557X - p. 1384 - 1395.
    channel catfish - rainbow-trout - fresh-water - ictalurus-punctatus - oncorhynchus-mykiss - na+/k+-atpase - carpio l. - toxicity - chloride - mechanism
    The nitrite threshold concentration in rearing water of African catfish (Clarias gariepinus) was assessed. African catfish with an initial mean (SD) weight of 219.7 (57.8) g were exposed to an increasing range of water nitrite from 6 (Control) to 928 µM nitrite for 28 days. Mean (SD) plasma nitrite concentrations increased from 5.0 (3.6) to 32.5 (12.6) µM at 928 µM ambient nitrite. The increase in nitrite was accompanied by gradual increase in plasma nitrate from 41.6 (28.4) µM to 420.2 (106.4) µM. Haematocrit, haemoglobin, methemoglobin, plasma concentrations of cortisol, glucose, lactate, osmolality, gill morphology and branchial Na+/K+-ATPase activity were not affected. Feed intake, final weight, SGR, FCR and mortality were not affected. We advise not to exceed a water nitrite concentration of 43 µM (0.6 mg L-1 NO2--N) to prevent the risk of reduced growth and feed intake in African catfish aquaculture.
    Water quality status and trends in agriculture-dominated headwaters; a national monitoring network for assessing the effectiveness of national and European manure legislation in The Netherlands
    Rozemeijer, J.C. ; Klein, J. ; Broers, H.P. ; Tol-Leenders, T.P. van; Grift, B. van der - \ 2014
    Environmental Monitoring and Assessment 186 (2014)12. - ISSN 0167-6369 - p. 8981 - 8995.
    flow route contributions - long-term change - surface-water - nutrient concentrations - temporal variability - groundwater quality - catchment discharge - fresh-water - land-use - phosphorus
    Large nutrient losses to groundwater and surface waters are a major drawback of the highly productive agricultural sector in The Netherlands. The resulting high nutrient concentrations in water resources threaten their ecological, industrial, and recreational functions. To mitigate eutrophication problems, legislation on nutrient application in agriculture was enforced in 1986 in The Netherlands. The objective of this study was to evaluate this manure policy by assessing the water quality status and trends in agriculture-dominated headwaters. We used datasets from 5 agricultural test catchments and from 167 existing monitoring locations in agricultural headwaters. Trend analysis for these locations showed a fast reduction of nutrient concentrations after the enforcement of the manure legislation (median slopes of -0.55 mg/l per decade for total nitrogen (N-tot) and -0.020 mg/l per decade for total phosphorus (P-tot)). Still, up to 76 % of the selected locations currently do not comply with either the environmental quality standards (EQSs) for nitrogen (N-tot) or phosphorus (P-tot). This indicates that further improvement of agricultural water quality is needed. We observed that weather-related variations in nutrient concentrations strongly influence the compliance testing results, both for individual locations and for the aggregated results at the national scale. Another important finding is that testing compliance for nutrients based on summer average concentrations may underestimate the agricultural impact on ecosystem health. The focus on summer concentrations does not account for the environmental impact of high winter loads from agricultural headwaters towards downstream water bodies.
    Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water
    Grift, B. van der; Rozemeijer, J.C. ; Griffioen, J. ; Velde, Y. van der - \ 2014
    Hydrology and Earth System Sciences 18 (2014)11. - ISSN 1027-5606 - p. 4687 - 4702.
    suspended sediment - ferrous iron - fresh-water - phosphorus limitation - nutrient dynamics - fe(ii) oxidation - arsenic removal - natural-waters - riparian zone - river
    The retention of phosphorus in surface waters through co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from groundwater into surface water in an agricultural experimental catchment of a small lowland river. We physically separated tube drain effluent from groundwater discharge before it entered a ditch in an agricultural field. Through continuous discharge measurements and weekly water quality sampling of groundwater, tube drain water, exfiltrated groundwater, and surface water, we investigated Fe(II) oxidation kinetics and P immobilization processes. The oxidation rate inferred from our field measurements closely agreed with the general rate law for abiotic oxidation of Fe(II) by O-2. Seasonal changes in climatic conditions affected the Fe(II) oxidation process. Lower pH and lower temperatures in winter (compared to summer) resulted in low Fe oxidation rates. After exfiltration to the surface water, it took a couple of days to more than a week before complete oxidation of Fe(II) is reached. In summer time, Fe oxidation rates were much higher. The Fe concentrations in the exfiltrated groundwater were low, indicating that dissolved Fe(II) is completely oxidized prior to inflow into a ditch. While the Fe oxidation rates reduce drastically from summer to winter, P concentrations remained high in the groundwater and an order of magnitude lower in the surface water throughout the year. This study shows very fast immobilization of dissolved P during the initial stage of the Fe(II) oxidation process which results in P-depleted water before Fe(II) is completely depleted. This cannot be explained by surface complexation of phosphate to freshly formed Fe-oxyhydroxides but indicates the formation of Fe(III)-phosphate precipitates. The formation of Fe(III)-phosphates at redox gradients seems an important geochemical mechanism in the transformation of dissolved phosphate to structural phosphate and, therefore, a major control on the P retention in natural waters that drain anaerobic aquifers.
    Humic substances interfere with phosphate removal by lanthanum modified clay in controlling eutrophication
    Lurling, M.F.L.L.W. ; Waaijenberg, G.W.A.M. ; Oosterhout, J.F.X. - \ 2014
    Water Research 54 (2014). - ISSN 0043-1354 - p. 78 - 88.
    waterbodems - fosfaten - eutrofiëring - bioremediëring - laboratoriumproeven - water bottoms - phosphates - eutrophication - bioremediation - laboratory tests - rare-earth-elements - phosphorus-binding clay - organic-matter removal - modified bentonite clay - natural-waters - cyanobacterial toxins - polyaluminum chloride - cation binding - ion-binding - fresh-water
    The lanthanum (La) modified bentonite Phoslock® has been proposed as dephosphatisation technique aiming at removing Filterable Reactive Phosphorus (FRP) from the water and blocking the release of FRP from the sediment. In the modified clay La is expected the active ingredient. We conducted controlled laboratory experiments to measure the FRP removal by Phoslock® in the presence and absence of humic substances, as La complexation with humic substances might lower the effectiveness of La (Phoslock®) to bind FRP. The results of our study support the hypothesis that the presence of humic substances can interfere with the FRP removal by the La-modified bentonite. Both a short-term (1 d) and long-term (42 d) experiment were in agreement with predictions derived from chemical equilibrium modelling and showed lower FRP removal in presence of humic substances. This implies that in DOC-rich inland waters the applicability of exclusively Phoslock® as FRP binder should be met critically. In addition, we observed a strong increase of filterable La in presence of humic substances reaching in a week more than 270 µg La l-1 that would infer a violation of the Dutch La standard for surface water, which is 10.1 µg La l-1. Hence, humic substances are an important factor that should be given attention when considering chemical FRP inactivation as they might play a substantial role in lowering the efficacy of metal-based FRP-sorbents, which makes measurements of humic substances (DOC) as well as controlled experiments vital.
    Effect of Selected Plant Extracts and D- and L-Lysine on the Cyanobacterium Microcystis aeruginosa
    Lurling, M.F.L.L.W. ; Oosterhout, J.F.X. - \ 2014
    Water 6 (2014)6. - ISSN 2073-4441 - p. 1807 - 1825.
    moringa-oleifera seeds - controlling eutrophication - fresh-water - amino-acid - blooms - coagulation - inhibition - mechanism - substances - phosphorus
    We tested extracts from Fructus mume, Salvia miltiorrhiza and Moringa oleifera as well as L-lysine and D-Lysine as curative measures to rapidly suppress the cyanobacterium Microcystis aeruginosa NIVA-CYA 43. We tested these compounds under similar conditions to facilitate comparisons. We hypothesized that for each compound, relatively low concentrations—i.e., 5–50 mg L-1, would reduce M. aeruginosa biomass. At these low concentrations, only L-lysine caused a decline in M. aeruginosa biomass at =4.3 mg L-1. F. mume extract was effective to do so at high concentrations, i.e., at =240 mg L-1, but the others were virtually non-effective. Low pH caused by organic acids is a probable explanation for the effect of F. mume extract. No complete wipe-outs of the experimental population were achieved as Photosystem II efficiency showed a recovery after six days. L-lysine may be effective at low concentrations—meaning low material costs. However, the effect of L-lysine seems relatively short-lived. Overall, the results of our study did not support the use of the tested plant extracts and amino-acid as promising candidates for curative application in M. aeruginosa bloom control.
    Beating the blues: Is there any music in fighting cyanobacteria with ultrasound?
    Lurling, M.F.L.L.W. ; Tolman, Y. - \ 2014
    Water Research 66 (2014). - ISSN 0043-1354 - p. 361 - 373.
    oppervlaktewater - cyanobacteriën - ultrageluid - waterkwaliteit - surface water - cyanobacteria - ultrasound - water quality - anabaena-flos-aquae - microcystis-aeruginosa - effective microorganisms - harmful cyanobacteria - growth-inhibition - climate-change - bloom control - gas vesicles - fresh-water - eutrophication
    The hypothesis that cyanobacteria can be controlled by commercially available ultrasound transducers was tested in laboratory experiments with cultures of the cyanobacteria Anabaena sp., Cylindrospermopsis raciborskii and Microcystis aeruginosa and the green alga Scenedesmus obliquus that were grown in the absence or presence of ultrasound (mix of 20, 28 and 44 kHz). The Scenedesmus experiment also included a treatment with the zooplankton grazer Daphnia magna. Chlorophyll-a and biovolume-based growth of Anabaena was significantly lower in ultrasound exposed cultures than in controls. Particle based growth rates were higher in ultrasound treatments. Filaments were significantly shorter in ultrasound exposed cultures reflecting filament breakage. Photosystem II efficiency was not affected by ultrasound. In Cylindrospermopsis chlorophyll-a based growth rates and photosystem II efficiencies were similar in controls and ultrasound treatments, but biovolume-based growth was significantly lower in ultrasound exposed cultures compared to controls. Despite biovolume growth rates of the filamentous cyanobacteria were reduced in ultrasound treatments compared to controls, growth remained positive implying still a population increase. In Microcystis and Scenedesmus growth rates were similar in controls and ultrasound treatments. Hence, no effect of ultrasound on these phytoplankton species was found. Ultrasound should not be viewed "environmental friendly" as it killed all Daphnia within 15 min, releasing Scenedesmus from grazing control in the cultures. Based on our experiments and critical literature review, we conclude that there is no music in controlling cyanobacteria in situ with the commercially available ultrasound transducers we have tested.
    Effects of commercially available ultrasound on the zooplankton grazer Daphnia and consequent water greening in laboratory experiments
    Lürling, M.F.L.L.W. ; Tolman, Y. - \ 2014
    Water 6 (2014)11. - ISSN 2073-4441 - p. 3247 - 3263.
    algal bloom control - microcystis-aeruginosa - cyanobacterial toxins - fresh-water - eutrophication - phytoplankton - frequencies - ecosystems - marine
    We tested the hypothesis that ultrasound in controlling cyanobacteria and algal blooms is “environmental friendly” by exposing the non-target zooplankton grazer Daphnia magna to ultrasound produced by commercially available ultrasound transducers. In populations of 15 Daphnia (~2 mm body size) exposed in 800 mL of water to ultrasound supplied at 20 kHz, 28 kHz, 36 kHz or 44 kHz, all animals were killed between 10 min (44 kHz) and 135 min (20 kHz). Differently sized Daphnia (0.7–3.2 mm) were all killed between 4 and 30 min when exposed to 44 kHz. Increasing water volumes up to 3.2 L and thus lowering the ultrasound intensity did not markedly increase survival of Daphnia exposed to 44 kHz ultrasound. A tank experiment with six 85 L tanks containing a mixture of green algae, cyanobacteria and D. magna was performed to study the effect of ultrasound over a longer time period (25 d). In controls, when Daphnia flourished, algal biomass dropped and the water became clear. In contrast, in ultrasound treatments, Daphnia abundance was extremely low releasing phytoplankton from grazing control, which resulted in high phytoplankton biomass. Hence, we conclude that ultrasound from commercially available transducers sold to clear ponds, aquaria and small reservoirs, should not be considered environmentally friendly and cannot be viewed as efficient in controlling phytoplankton.
    Alternative stable states in large shallow lakes?
    Janssen, A.B.G. ; Teurlincx, S. ; An, S.Q. ; Janse, J.H. ; Paerl, H. ; Mooij, W.M. - \ 2014
    Journal of Great Lakes Research 40 (2014)4. - ISSN 0380-1330 - p. 813 - 826.
    catastrophic regime shifts - ecosystem model pclake - drinking-water source - detroit river system - taihu lake - fresh-water - aquatic vegetation - spatiotemporal patterns - macrophyte communities - spatial heterogeneity
    Many lakes worldwide are experiencing great change due to eutrophication. Consequently, species composition changes, toxic algal blooms proliferate, and drinking water supplies dwindle. The transition to the deteriorated state can be catastrophic with an abrupt change from macrophyte to phytoplankton domination. This has been shown repeatedly in small lakes. Whether such alternative stable states also exist in large shallow lakes is less clear, however. Here we discuss the characteristics that give rise to alternative stable states in large shallow lakes either in the lake as whole or restricted to specific regions of the lake. We include the effect of lake size, spatial heterogeneity and internal connectivity on a lake's response along the eutrophication axis. As a case study, we outline the eutrophication history of Lake Taihu (China) and illustrate how lake size, spatial heterogeneity and internal connectivity can explain the observed spatial presence of different states. We discuss whether these states can be alternatively stable by comparing the data with model output (PCLake). These findings are generalised for other large, shallow lakes. We conclude that locations with prevailing size effects generally lack macrophytes; and, therefore, alternative stable states are unlikely to occur there. However, most large shallow lakes have macrophytes whose presence remains unexplained when only size effect is taken into account. By including spatial heterogeneity in the analysis, the presence of macrophytes and alternative stable states in large shallow lakes is better understood. Finally, internal connectivity is important because a high internal connectivity reduces the stability of alternative states.
    Effects of hydrogen peroxide and ultrasound on biomass reduction and toxin release in the cyanobacterium, microcystis aeruginosa
    Lurling, M.F.L.L.W. ; Meng, D. ; Faassen, E.J. - \ 2014
    Toxins 6 (2014)12. - ISSN 2072-6651 - p. 3260 - 3280.
    waste stabilization ponds - water-treatment processes - blue-green-algae - fresh-water - human health - harmful cyanobacteria - liquid-chromatography - phosphatase bioassay - membrane integrity - mass spectrometry
    Cyanobacterial blooms are expected to increase, and the toxins they produce threaten human health and impair ecosystem services. The reduction of the nutrient load of surface waters is the preferred way to prevent these blooms; however, this is not always feasible. Quick curative measures are therefore preferred in some cases. Two of these proposed measures, peroxide and ultrasound, were tested for their efficiency in reducing cyanobacterial biomass and potential release of cyanotoxins. Hereto, laboratory assays with a microcystin (MC)-producing cyanobacterium (Microcystis aeruginosa) were conducted. Peroxide effectively reduced M. aeruginosa biomass when dosed at 4 or 8 mg L-1, but not at 1 and 2 mg L-1. Peroxide dosed at 4 or 8 mg L-1 lowered total MC concentrations by 23%, yet led to a significant release of MCs into the water. Dissolved MC concentrations were nine-times (4 mg L-1) and 12-times (8 mg L-1 H2O2) higher than in the control. Cell lysis moreover increased the proportion of the dissolved hydrophobic variants, MC-LW and MC-LF (where L = Leucine, W = tryptophan, F = phenylalanine). Ultrasound treatment with commercial transducers sold for clearing ponds and lakes only caused minimal growth inhibition and some release of MCs into the water. Commercial ultrasound transducers are therefore ineffective at controlling cyanobacteria.
    Enhanced Input of Terrestrial Particulate Organic Matter Reduces the Resilience of the Clear-Water State of Shallow Lakes: A Model Study
    Lischke, B. ; Hilt, S. ; Janse, J.H. ; Kuiper, J.J. ; Mehner, T. ; Mooij, W.M. ; Gaedke, U. - \ 2014
    Ecosystems 17 (2014)4. - ISSN 1432-9840 - p. 616 - 626.
    climate-change - food webs - humic substances - resource use - fresh-water - loch ness - land-use - carbon - ecosystem - phosphorus
    The amount of terrestrial particulate organic matter (t-POM) entering lakes is predicted to increase as a result of climate change. This may especially alter the structure and functioning of ecosystems in small, shallow lakes which can rapidly shift from a clear-water, macrophyte-dominated into a turbid, phytoplankton-dominated state. We used the integrative ecosystem model PCLake to predict how rising t-POM inputs affect the resilience of the clear-water state. PCLake links a pelagic and benthic food chain with abiotic components by a number of direct and indirect effects. We focused on three pathways (zoobenthos, zooplankton, light availability) by which elevated t-POM inputs (with and without additional nutrients) may modify the critical nutrient loading thresholds at which a clear-water lake becomes turbid and vice versa. Our model results show that (1) increased zoobenthos biomass due to the enhanced food availability results in more benthivorous fish which reduce light availability due to bioturbation, (2) zooplankton biomass does not change, but suspended t-POM reduces the consumption of autochthonous particulate organic matter which increases the turbidity, and (3) the suspended t-POM reduces the light availability for submerged macrophytes. Therefore, light availability is the key process that is indirectly or directly changed by t-POM input. This strikingly resembles the deteriorating effect of terrestrial dissolved organic matter on the light climate of lakes. In all scenarios, the resilience of the clear-water state is reduced thus making the turbid state more likely at a given nutrient loading. Therefore, our study suggests that rising t-POM input can add to the effects of climate warming making reductions in nutrient loadings even more urgent.
    Resolving the polyphyletic nature of Pyricularia (Pyriculariaceae)
    Klaubauf, S. ; Tharreau, D. ; Fournier, E. ; Groenewald, J.Z. ; Crous, P.W. ; Vries, R.P. de; Lebrun, M.H. - \ 2014
    Studies in Mycology 79 (2014). - ISSN 0166-0616 - p. 85 - 120.
    rice blast fungus - magnaporthe-oryzae - juncus-roemerianus - molecular-data - fresh-water - grisea - phylogeny - genera - specificity - resistance
    Species of Pyricularia (magnaporthe-like sexual morphs) are responsible for major diseases on grasses. Pyricularia oryzae (sexual morph Magnaporthe oryzae) is responsible for the major disease of rice called rice blast disease, and foliar diseases of wheat and millet, while Pyricularia grisea (sexual morph Magnaporthe grisea) is responsible for foliar diseases of Digitaria. Magnaporthe salvinii, M. poae and M. rhizophila produce asexual spores that differ from those of Pyricularia sensu stricto that has pyriform, 2-septate conidia produced on conidiophores with sympodial proliferation. Magnaporthe salvinii was recently allocated to Nakataea, while M. poae and M. rhizophila were placed in Magnaporthiopsis. To clarify the taxonomic relationships among species that are magnaporthe- or pyricularia-like in morphology, we analysed phylogenetic relationships among isolates representing a wide range of host plants by using partial DNA sequences of multiple genes such as LSU, ITS, RPB1, actin and calmodulin. Species of Pyricularia s. str. belong to a monophyletic clade that includes all P. oryzae/P. grisea isolates tested, defining the Pyriculariaceae, which is sister to the Ophioceraceae, representing two novel families. These clades are clearly distinct from species belonging to the Gaeumannomyces pro parte/Magnaporthiopsis/Nakataea generic complex that are monophyletic and define the Magnaporthaceae. A few magnaporthe- and pyricularia-like species are unrelated to Magnaporthaceae and Pyriculariaceae. Pyricularia oryzae/P. grisea isolates cluster into two related clades. Host plants such as Eleusine, Oryza, Setaria or Triticum were exclusively infected by isolates from P. oryzae, while some host plant such as Cenchrus, Echinochloa, Lolium, Pennisetum or Zingiber were infected by different Pyricularia species. This demonstrates that host range cannot be used as taxonomic criterion without extensive pathotyping. Our results also show that the typical pyriform, 2-septate conidium morphology of P. grisea/P. oryzae is restricted to Pyricularia and Neopyricularia, while most other genera have obclavate to more ellipsoid 2-septate conidia. Some related genera (Deightoniella, Macgarvieomyces) have evolved 1-septate conidia. Therefore, conidium morphology cannot be used as taxonomic criterion at generic level without phylogenetic data. We also identified 10 novel genera, and seven novel species. A re-evaluation of generic and species concepts within Pyriculariaceae is presented, and novelties are proposed based on morphological and phylogenetic data.
    Odonata of Curacao, southern Caribbean, with an update to the fauna of the ABC islands
    Paulson, D.R. ; Haseth, C. de; Debrot, A.O. - \ 2014
    The International Journal of Odonatology 17 (2014)4. - ISSN 1388-7890 - p. 237 - 249.
    fresh-water - west-indies - bonaire - libellulidae - anisoptera - orthemis - fishes - aruba
    A three-year field study (January 2011–December 2013) of the Odonata of Curaçao, supported by photos and exuvial collections, recorded a total of 21 species from the island, almost doubling its previously known fauna. The lists of Odonata known from Aruba and Bonaire were also updated by specimen and photo records, and 24 species are now known from these three islands. During the period of the study, odonates decreased in abundance and diversity in Curaçao, apparently because heavy rains just before the study began led to colonization of the island by several nonresident species that subsequently declined and disappeared as wetlands diminished during a period with normal rainfall
    The Global Invertebrate Genomics Alliance (GIGA). 2014. Developing Community Resources to Study Diverse Invertebrate Genomes
    Pomponi, S.A. - \ 2014
    Journal of Heredity 105 (2014)1. - ISSN 0022-1503 - p. 1 - 18.
    marine natural-products - gene-expression - draft genome - tetranychus-urticae - human microbiome - whole-genome - fresh-water - evolution - phylogeny - coral
    Over 95% of all metazoan (animal) species comprise the “invertebrates,” but very few genomes from these organisms have been sequenced. We have, therefore, formed a “Global Invertebrate Genomics Alliance” (GIGA). Our intent is to build a collaborative network of diverse scientists to tackle major challenges (e.g., species selection, sample collection and storage, sequence assembly, annotation, analytical tools) associated with genome/transcriptome sequencing across a large taxonomic spectrum. We aim to promote standards that will facilitate comparative approaches to invertebrate genomics and collaborations across the international scientific community. Candidate study taxa include species from Porifera, Ctenophora, Cnidaria, Placozoa, Mollusca, Arthropoda, Echinodermata, Annelida, Bryozoa, and Platyhelminthes, among others. GIGA will target 7000 noninsect/nonnematode species, with an emphasis on marine taxa because of the unrivaled phyletic diversity in the oceans. Priorities for selecting invertebrates for sequencing will include, but are not restricted to, their phylogenetic placement; relevance to organismal, ecological, and conservation research; and their importance to fisheries and human health. We highlight benefits of sequencing both whole genomes (DNA) and transcriptomes and also suggest policies for genomic-level data access and sharing based on transparency and inclusiveness.
    Post-prandial changes in plasma mineral levels in rainbow trout fed a complete plant ingredient based diet and the effect of supplemental di-calcium phosphate
    Antony Jesu Prabhu, P. ; Schrama, J.W. ; Mariojouls, C. ; Godin, S. ; Fontagné-Dicharry, S. ; Geurden, I. ; Surget, A. ; Bouyssiere, B. ; Kaushik, S.J. - \ 2014
    Aquaculture 430 (2014). - ISSN 0044-8486 - p. 34 - 43.
    salmon salmo-salar - fecal phosphorus excretion - european sea-bass - low fish-meal - oncorhynchus-mykiss - atlantic salmon - fresh-water - channel catfish - dicentrarchus-labrax - tricalcium phosphate
    Post-prandial changes in plasma mineral levels and utilisation of minerals in rainbow trout fed complete plant ingredient based diets with or without supplemental di-calcium phosphate (DCP) were studied over an 8 week period. Three diets were used: diet M was FM and fish oil (FO) based diet (control); diets VP0 and VP + (V diets) were completely based on plant derived protein and lipid sources. One of the V diets (VP +) was supplemented with DCP to supply 5 g kg- 1 dry matter available phosphorus (P); while the other diet (VP0) was not supplemented with DCP. Change in dietary protein source significantly affected the post-prandial pattern in plasma levels of P (p <0.05), Ca (p <0.007), Mg (p <0.001) and Zn (p <0.03). Area under the curve analysis indicated that compared to VP0, DCP supplementation in VP + improved plasma levels of P (p <0.01) and K (p <0.05); Cu (p <0.002), Se (p <0.009) and Zn (p <0.001) levels were reduced while Ca, Mg and Fe levels were unaffected (p > 0.05). Based on measurement of apparent digestibility, growth and whole body composition analyses, mineral balances were established showing that supplementation of DCP led to significant increase in whole body P concentration and P retention in VP +, comparable to fish fed diet M with significantly (p <0.05) reduced faecal and non-faecal P losses. There was improved post-absorptive retention (as % of available intake) of Ca (p <0.05), Mg (p <0.05) and K (p <0.05) in VP + compared to VP0. Utilisation of Cu (p <0.05) and Zn (p <0.01) was negatively affected. DCP supplementation to complete plant ingredient based diet increased the post-prandial plasma levels, whole body concentration and utilisation of macro-minerals (P, Ca, Mg and K) whereas that of micro-minerals especially Zn and Cu were negatively affected.
    Comparative effects of zinc oxide nanoparticles and dissolved zinc on zebrafish embryos and eleuthero-embryos: Importance of zinc ions
    Brun, N.R. ; Lenz, M. ; Wehrli, B. ; Fent, K. - \ 2014
    Science of the Total Environment 476-477 (2014). - ISSN 0048-9697 - p. 657 - 666.
    in-vitro evaluation - zno nanoparticles - oxidative stress - fresh-water - aggregation kinetics - silver nanoparticles - cell-line - bulk zno - toxicity - nanomaterials
    The increasing use of zinc oxide nanoparticles (nZnO) and their associated environmental occurrence make it necessary to assess their potential effects on aquatic organisms. Upon water contact, nZnO dissolve partially to zinc (Zn(II)). To date it is not yet completely understood, whether effects of nZnO are solely or partly due to dissolved Zn(II). Here we compare potential effects of 0.2, 1 and 5 mg/L nZnO and corresponding concentrations of released Zn(II) by water soluble ZnCl2 to two development stages of zebrafish, embryos and eleuthero-embryos, by analysing expressional changes by RT-qPCR. Another objective was to assess uptake and tissue distribution of Zn(II). Laser ablation-ICP-MS analysis demonstrated that uptake and tissue distribution of Zn(II) were identical for nZnO and ZnCl2 in eleuthero-embryos. Zn(II) was found particularly in the retina/pigment layer of eyes and brain. Both nZnO and dissolved Zn(II) derived from ZnCl2 had similar inhibiting effects on hatching, and they induced similar expressional changes of target genes. At 72 hours post fertilization (hpf), both nZnO and Zn(II) delayed hatching at all doses, and inhibited hatching at 1 and 5 mg/L at 96 hpf. Both nZnO and Zn(II) lead to induction of metallothionein (mt2) in both embryos and eleuthero-embryos at all concentrations. Transcripts of oxidative stress related genes cat and Cu/Zn sod were also altered. Moreover, we show for the first time that nZnO exposure results in transcriptional changes of pro-inflammatory cytokines IL-1ß and TNFa. Overall, transcriptional alterations were higher in embryos than eleuthero-embryos. The similarities of the effects lead to the conclusion that effects of nZnO are mainly related to the release of Zn(II).
    Lanthanum from a modified clay used in eutrophication control is bioavailable to the marbled crayfish (Procambarus fallax f. virginalis)
    Oosterhout, F. van; Goitom, E. ; Roessink, I. ; Lurling, M. - \ 2014
    PLoS ONE 9 (2014)7. - ISSN 1932-6203 - 9 p.
    phosphorus binding clay - copper nickel smelters - rare-earth-elements - heavy-metals - fresh-water - lakes - toxicity - accumulation - phoslock(r) - sediment
    To mitigate eutrophication in fresh standing waters the focus is on phosphorus (P) control, i.e. on P inflows to a lake as well as a lake's sediment as internal P source. The in-lake application of the lanthanum (La) modified clays – i.e. La modified bentonite (Phoslock) or La modified kaolinite, aim at dephosphatising the water column and at reducing the release of P from a lake's sediment. Application of these clays raises the question whether La from these clays can become bioavailable to biota. We investigated the bioavailability of La from Phoslock in a controlled parallel groups experiment in which we measured the La in carapace, gills, ovaries, hepatopancreas and abdominal muscle after 0, 14 and 28 days of exposure to Phoslock. Expressing the treatment effect as the difference of the median concentration between the two treatment groups (Phoslock minus control group) yield the following effects, the plus sign (+) indicating an increase, concentrations in µg g-1 dry weight: Day 14: carapace +10.5 µg g-1, gills +112 µg g-1, ovaries +2.6 µg g-1, hepatopancreas +32.9 µg g-1 and abodminal muscle +3.2 µg g-1. Day 28: carapace +17.9 µg g-1; gills +182 µg g-1; ovaries +2.2 µg g-1; hepatopancreas +41.9 µg g-1 and abodminal muscle +7.6 µg g-1, all effects were statistically significant. As La from Phoslock is bio-available to and taken up by the marbled crayfishes (Procambarus fallax f. virginalis), we advocate that the application of in-lake chemical water treatments to mitigate eutrophication should be accompanied by a thorough study on potential side effects
    Vibrio vulnificus outbreaks in Dutch eel farms since 1996: strain diversity and impact.
    Haenen, O.L.M. ; Zanten, E. van; Jansen, R. ; Roozenburg, I. ; Engelsma, M.Y. ; Dijkstra, A. ; Boers, S.A. ; Voorbergen-Laarman, M. ; Möller, A.V.M. - \ 2014
    Diseases of Aquatic Organisms 108 (2014)3. - ISSN 0177-5103 - p. 201 - 209.
    diseased european eel - anguilla-anguilla - biotype 2 - clinical-manifestations - fresh-water - serovar-e - infection - pathogen - tilapia - fish
    Vibrio vulnificus is a potentially zoonotic bacterial pathogen of fish, which can infect humans (causing necrotic fasciitis). We analysed 24 V. vulnificus isolates (from 23 severe eel disease outbreaks in 8 Dutch eel farms during 1996 to 2009, and 1 clinical strain from an eel farmer) for genetic correlation and zoonotic potential. Strains were typed using biotyping and molecular typing by high-throughput multilocus sequence typing (hiMLST) and REP-PCR (Diversilab®). We identified 19 strains of biotype 1 and 5 of biotype 2 (4 from eels, 1 from the eel farmer), that were subdivided into 8 MLST types (ST) according to the international standard method. This is the first report of V. vulnificus biotype 1 outbreaks in Dutch eel farms. Seven of the 8 STs, of unknown zoonotic potential, were newly identified and were deposited in the MLST database. The REP-PCR and the MLST were highly concordant, indicating that the REP-PCR is a useful alternative for MLST. The strains isolated from the farmer and his eels were ST 112, a known potential zoonotic strain. Antimicrobial resistance to cefoxitin was found in most of the V. vulnificus strains, and an increasing resistance to quinolones, trimethoprim + sulphonamide and tetracycline was found over time in strain ST 140. Virulence testing of isolates from diseased eels is recommended, and medical practitioners should be informed about the potential risk of zoonotic infections by V. vulnificus from eels for the prevention of infection especially among high-risk individuals. Additional use of molecular typing methods such as hiMLST and Diversilab® is recommended for epidemiological purposes during V. vulnificus outbreaks.
    Check title to add to marked list
    << previous | next >>

    Show 20 50 100 records per page

    Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.