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 

    Records 1 - 20 / 148

    • help
    • print

      Print search results

    • export

      Export search results

    Check title to add to marked list
    The Effect of Calcium Buffering and Calcium Sensor Type on the Sensitivity of an Array-Based Bitter Receptor Screening Assay.
    Roelse, M. ; Wehrens, H.R.M.J. ; Henquet, M.G.L. ; Witkamp, R.F. ; Hall, R.D. ; Jongsma, M.A. - \ 2019
    Chemical Senses 44 (2019)7. - ISSN 0379-864X - p. 497 - 505.
    The genetically encoded calcium sensor protein Cameleon YC3.6 has previously been applied for functional G protein–coupled receptor screening using receptor cell arrays. However, different types of sensors are available, with a wide range in [Ca2+] sensitivity, Hill coefficients, calcium binding domains, and fluorophores, which could potentially improve the performance of the assay. Here, we compared the responses of 3 structurally different calcium sensor proteins (Cameleon YC3.6, Nano140, and Twitch2B) simultaneously, on a single chip, at different cytosolic expression levels and in combination with 2 different bitter receptors, TAS2R8 and TAS2R14. Sensor concentrations were modified by varying the amount of calcium sensor DNA that was printed on the DNA arrays prior to reverse transfection. We found that ~2-fold lower concentrations of calcium sensor protein, by transfecting 4 times less sensor-coding DNA, resulted in more sensitive bitter responses. The best results were obtained with Twitch2B, where, relative to YC3.6 at the default DNA concentration, a 4-fold lower DNA concentration increased sensitivity 60-fold and signal strength 5- to 10-fold. Next, we compared the performance of YC3.6 and Twitch2B against an array with 11 different bitter taste receptors. We observed a 2- to 8-fold increase in sensitivity using Twitch2B compared with YC3.6. The bitter receptor arrays contained 300 spots and could be exposed to a series of 18 injections within 1 h resulting in 5400 measurements. These optimized sensor conditions provide a basis for enhancing receptomics calcium assays for receptors with poor Ca2+ signaling and will benefit future high-throughput receptomics experiments.
    Hoe margrietjes bladluizen de stuipen op het lijf jagen
    Jongsma, M.A. - \ 2019
    'Maken gewone margrietjes ook die alarmgeurstof aan?'
    Jongsma, M.A. - \ 2019

    Maarten Jongsma: 'De natuur zit zo complex in elkaar ...'

    Defense of pyrethrum flowers: repelling herbivore and recruiting carnivore by producing aphid alarm pheromone
    Li, Jinjin de; Hu, Hao ; Mao, Jing ; Yu, Lu de; Stoopen, Geert ; Wang, Manqun ; Mumm, Roland ; Ruijter, Norbert C.A. de; Dicke, Marcel ; Jongsma, Maarten A. ; Wang, Caiyun - \ 2019
    New Phytologist 223 (2019)3. - ISSN 0028-646X - p. 1607 - 1620.
    E)‐β‐farnesene (EβF) is the predominant constituent of the alarm pheromone of most aphid pest species. Moreover, natural enemies of aphids use EβF to locate their aphid prey. Some plant species emit EβF, potentially as a defense against aphids, but field demonstrations are lacking.Here, we present field and laboratory studies of flower defense showing that ladybird beetles are predominantly attracted to young stage‐2 pyrethrum flowers that emitted the highest and purest levels of EβF. By contrast, aphids were repelled by EβF emitted by S2 pyrethrum flowers. Although peach aphids can adapt to pyrethrum plants in the laboratory, aphids were not recorded in the field. Pyrethrum's (E)‐β‐farnesene synthase (EbFS) gene is strongly expressed in inner cortex tissue surrounding the vascular system of the aphid‐preferred flower receptacle and peduncle, leading to elongated cells filled with EβF. Aphids that probe these tissues during settlement encounter and ingest plant EβF as evidenced by the release in honeydew. These EβF concentrations in honeydew induce aphid alarm responses, suggesting an extra layer of this defense.Collectively, our data elucidate a defensive mimicry in pyrethrum flowers: the developmentally regulated and tissue‐specific EβF accumulation and emission both prevents attack by aphids and recruits aphid predators as bodyguards.
    Pyrethric acid of natural pyrethrin insecticide: complete pathway elucidation and reconstitution in Nicotiana benthamiana
    Xu, H. ; Li, Wei ; Schilmiller, Anthony L. ; Eekelen, H.D.L.M. van; Vos, C.H. de; Jongsma, M.A. ; Pichersky, E. - \ 2019
    New Phytologist 223 (2019)2. - ISSN 0028-646X - p. 751 - 765.
    In the natural pesticides known as pyrethrins, which are esters produced in flowers of Tanacetum cinerariifolium (Asteraceae), the monoterpenoid acyl moiety is pyrethric acid or chrysanthemic acid.
    We show here that pyrethric acid is produced from chrysanthemol in six steps catalyzed by four enzymes, the first five steps occurring in the trichomes covering the ovaries and the last one occurring inside the ovary tissues.
    Three steps involve the successive oxidation of carbon 10 (C10) to a carboxylic group by TcCHH, a cytochrome P450 oxidoreductase. Two other steps involve the successive oxidation of the hydroxylated carbon 1 to give a carboxylic group by TcADH2 and TcALDH1, the same enzymes that catalyze these reactions in the formation of chrysanthemic acid. The ultimate result of the actions of these three enzymes is the formation of 10‐carboxychrysanthemic acid in the trichomes. Finally, the carboxyl group at C10 is methylated by TcCCMT, a member of the SABATH methyltransferase family, to give pyrethric acid. This reaction occurs mostly in the ovaries.
    Expression in N. benthamiana plants of all four genes encoding aforementioned enzymes, together with TcCDS, a gene that encodes an enzyme that catalyzes the formation of chrysanthemol, led to the production of pyrethric acid.
    Statistical models discriminating between complex samples measured with microfluidic receptor-cell arrays
    Wehrens, H.R.M.J. ; Roelse, M. ; Henquet, M.G.L. ; Lenthe, M.S. van; Goedhart, Paul ; Jongsma, M.A. - \ 2019
    PLoS ONE 14 (2019)4. - ISSN 1932-6203
    Data analysis for flow-based in-vitro receptomics array, like a tongue-on-a-chip, is complicated by the relatively large variability within and between arrays, transfected DNA types, spots, and cells within spots. Simply averaging responses of spots of the same type would lead to high variances and low statistical power. This paper presents an approach based on linear mixed models, allowing a quantitative and robust comparison of complex samples and indicating which receptors are responsible for any differences. These models are easily extended to take into account additional effects such as the build-up of cell stress and to combine data from replicated experiments. The increased analytical power this brings to receptomics research is discussed.
    An Integrated System for the Automated Recording and Analysis of Insect Behavior in T-maze Arrays
    Jongsma, M.A. ; Thoen, H. ; Poleij, L.M. ; Wiegers, G.L. ; Goedhart, P.W. ; Dicke, M. ; Noldus, Lucas P.J.J. ; Kruisselbrink, J.W. - \ 2019
    Frontiers in Plant Science 10 (2019). - ISSN 1664-462X
    Host-plant resistance to insects like thrips and aphids is a complex trait that is difficult to phenotype quickly and reliably. Here, we introduce novel hardware and software to facilitate insect choice assays and automate the acquisition and analysis of movement tracks. The hardware consists of an array of individual T-mazes allowing simultaneous release of up to 90 insect individuals from their individual cage below each T-maze with choice of two leaf disks under a video camera. Insect movement tracks are acquired with computer vision software (EthoVision) and analyzed with EthoAnalysis, a novel software package that allows for automated reporting of highly detailed behavior parameters and
    statistical analysis. To validate the benefits of the system we contrasted two Arabidopsis accessions that were previously analyzed for differential resistance to western flower thrips. Results of two trials with 40 T-mazes are reported and we show how we arrived at optimized settings for the different filters and statistics. The statistics are reported in terms of frequency, duration, distance and speed of behavior events, both as sum totals and event averages, and both for the total trial period and in time bins of 1 h. Also included are higher level analyses with subcategories like short-medium-long events and slow-medium-fast events. The time bins showed how some behavior elements are more descriptive of differences between the genotypes during the first hours, whereas
    others are constant or become more relevant at the end of an 8 h recording. The three overarching behavior categories, i.e., choice, movement, and halting, were automatically corrected for the percentage of time thrips were detected and 24 out of 38 statistics of behavior parameters differed by a factor 2–6 between the accessions. The analysis resulted in much larger contrasts in behavior traits than reported previously. Compared to leaf damage assays on whole plants or detached leaves that take a week or more to complete, results were obtained in 8 h, with more detail, fewer individuals and higher significance. The potential value of the new integrated system, named EntoLab, for discovery of genetic traits in plants and insects by high throughput screening of large populations is discussed.
    Receptomics: Calcium imaging of sensory receptor cell arrays in a microfluidic system and novel applications for food screening
    Roelse, M. ; Henquet, M.G.L. ; Jongsma, M.A. - \ 2018
    Reverse-transfected cell arrays in microfluidic systems have strong potential to perform large-scale parallel screening of GPCR libraries. We have successfully combined the multi-variable nature of a receptor cell array with microfluidics allowing for controlled and sequential sample dosing [1]. Our receptomics platform uniquely allows for dosing of small sample quantities against a large receptor library including controls for host cell responses and sample colour. Compared to existing microtiter-plate systems it can be applied more efficiently for the screening of off-target effects and the discovery of bioactivities in complex extracts with strong and variable host cell responses. The sequential injection format allowed the development of powerful spot-based statistical models to discriminate between a host cell response and the superimposed specific GPCR response.
    Zintuigen nagebootst
    Jongsma, M.A. - \ 2018

    Wageningse onderzoekers ontwikkelen een techniek om met smaak- en geurreceptoren onze reactie op voedingsstoffen te meten.

    ‘Met proteomics en metabolomics kun je in een tomaat wel honderden verbindingen identificeren, maar dat zegt niets over de smaakfunctie. Door de grote hoeveelheid variabelen is het bijna een onoplosbare puzzel.’

    Noord Korea klopt aan bij WUR
    Jongsma, M.A. - \ 2018

    Noord-Korea wil graag dat de Nederlandse overheid investeert in hun landbouw’, zegt Jongsma, werkzaam bij Wageningen Plant Research. ‘Landbouw is neutraal terrein - politiek gezien. Noord-Korea krijgt nu al voedselhulp van de VN.’ Het Noord-Koreaanse regime is met name geïnteresseerd in de Nederlandse kastechnologie voor de tuinbouw. ‘Ze hebben grootschalige kassencomplexen en weten dat er veel kennis in Nederland beschikbaar is.’

    Koning dineert met ambassadeur van Noord-Korea
    Jongsma, M.A. - \ 2018

    Nederland haalt voorzichtig de banden met Noord-Korea aan. De koning sprak onlangs zelfs al even met de Noord-Koreaanse VN-ambassadeur. Ondernemers bereiden een handelsmissie voor.

    Geur- en smaakstofmeting met 'tong- en neus-op-een-chip' in pilotfase Receptomics
    Jongsma, M.A. ; Roelse, M. - \ 2018
    'Tong op chip' maaakt onderzoek zonder proefpersonen mogelijk
    Jongsma, M.A. - \ 2018

    Onderzoekers van Wageningen Plant Research hebben receptoren uit de mond en darmen van mensen ‘geprint’ op glasplaatjes. Daarmee kunnen ze voortaan zonder proefpersonen onderzoek doen naar voeding en medicijnen.

    Automated high-throughput individual tracking system for insect behavior : Applications on memory retention in parasitic wasps
    Bruijn, Jessica A.C. de; Vet, Louise E.M. ; Jongsma, Maarten A. ; Smid, Hans M. - \ 2018
    Journal of Neuroscience Methods 309 (2018). - ISSN 0165-0270 - p. 208 - 217.
    Cotesia glomerata - Learning - Memory retention - Nasonia vitripennis - Parasitic wasps - Tracking system

    Background: Insects are important models to study learning and memory formation in both an ecological and neuroscience context due to their small size, behavioral flexibility and ecological diversity. Measuring memory retention is often done through simple time-consuming set-ups, producing only a single parameter for conditioned behavior. We wished to obtain higher sample sizes with fewer individuals to measure olfactory memory retention more efficiently. New method: The high-throughput individual T-maze uses commercially available tracking software, Ethovision XT®, in combination with a Perspex stack of plates as small as 18 × 18 cm, which accommodates 36 olfactory T-mazes, where each individual wasp could choose between two artificial odors. Various behavioral parameters, relevant to memory retention, were acquired in this set-up; first choice, residence time, giving up time and zone entries. From these parameters a performance index was calculated as a measure of memory retention. Groups of 36 wasps were simultaneously tested within minutes, resulting in efficient acquisition of sufficiently high sample sizes. Results: This system was tested with two very different parasitic wasp species, the larval parasitoid Cotesia glomerata and the pupal parasitoid Nasonia vitripennis, and has proven to be highly suitable for testing memory retention in both these species. Comparison with existing methods: Unlike other bioassays, this system allows for both high-throughput and recording of detailed individual behavior. Conclusions: The high-throughput individual T-maze provides us with a standardized high-throughput, labor-efficient and cost-effective method to test various kinds of behavior, offering excellent opportunities for comparative studies of various aspects of insect behavior.

    Feasibility study plant extracts in Rwanda : Developing value chains in public private partnerships
    Jongschaap, R.E.E. ; Vos, C.H. de; Jongsma, M.A. - \ 2018
    Wageningen : Wageningen Research Foundation (WR) business unit Agrosystems Research (Report WPR 801) - 23
    In a mission to Rwanda in December 2017, important stakeholders from government, research institutes, universities and private enterprises were interviewed to elaborate on Public Private Partnerships (PPP), or triple helix collaborations for further development of plant extracts in the agricultural sector of Rwanda. Findings of the missions were shared in a debriefing with the ambassador and the agricultural council of the Kingdom of the Netherlands in Rwanda. During the mission, potential leads were shared with the University of Rwanda. Through the social enterprise Crosswise Works, most important issues were discussed and brought further in a workshop in January 2018, aimed at a follow up mission to the Netherlands in June 2018, and the start-up of PPP in Rwanda. To increase business opportunities for developing plant extract chains in Rwanda, further research, preferably in PPP would be required. Pyrethrum productivity can be increased, based on increasing pyrethrin content of the flowers (now 2% in Rwanda compared to 4% in other parts of the world), and improvement of the cropping system (direct seeding instead of transplanting). Local products from Pyrethrum might also be an option to explore. Artemisia extracts for the pharmaceutical industry has the potential to diversify the current plant extract portfolio of Rwandan organizations. Government bodies in collaboration with universities and research institutes, together with the private sector should investigate whether and how the development of the value chain can be accelerated, and how a good connection to the international market can be obtained.
    Calcium imaging of GPCR activation using arrays of reverse transfected HEK293 cells in a microfluidic system
    Roelse, Margriet ; Henquet, Maurice G.L. ; Verhoeven, Harrie A. ; Ruijter, Norbert C.A. De; Wehrens, Ron ; Lenthe, Marco S. Van; Witkamp, Renger F. ; Hall, Robert D. ; Jongsma, Maarten A. - \ 2018
    Sensors 18 (2018)2. - ISSN 1424-8220
    Cameleon YC3.6 - Cell array - GPCR - Microfluidics - NK1 receptor - Reverse transfection
    Reverse-transfected cell arrays in microfluidic systems have great potential to perform large-scale parallel screening of G protein-coupled receptor (GPCR) activation. Here, we report the preparation of a novel platform using reverse transfection of HEK293 cells, imaging by stereo-fluorescence microscopy in a flowcell format, real-time monitoring of cytosolic calcium ion fluctuations using the fluorescent protein Cameleon and analysis of GPCR responses to sequential sample exposures. To determine the relationship between DNA concentration and gene expression, we analyzed cell arrays made with variable concentrations of plasmid DNA encoding fluorescent proteins and the Neurokinin 1 (NK1) receptor. We observed pronounced effects on gene expression of both the specific and total DNA concentration. Reverse transfected spots with NK1 plasmid DNA at 1% of total DNA still resulted in detectable NK1 activation when exposed to its ligand. By varying the GPCR DNA concentration in reverse transfection, the sensitivity and robustness of the receptor response for sequential sample exposures was optimized. An injection series is shown for an array containing the NK1 receptor, bitter receptor TAS2R8 and controls. Both receptors were exposed 14 times to alternating samples of two ligands. Specific responses remained reproducible. This platform introduces new opportunities for high throughput screening of GPCR libraries.
    Modification of chrysanthemum odour and taste with chrysanthemol synthase induces strong dual resistance against cotton aphids
    Hu, Hao ; Li, Jinjin ; Delatte, Thierry ; Vervoort, Jacques ; Gao, Liping ; Verstappen, Francel ; Xiong, Wei ; Gan, Jianping ; Jongsma, Maarten A. ; Wang, Caiyun - \ 2018
    Plant Biotechnology Journal 16 (2018)8. - ISSN 1467-7644 - p. 1434 - 1445.
    Aphid resistance - Chrysanthemol synthase - Chrysanthemum - Double bioactivity - Glycoside - Terpene volatile
    Aphids are pests of chrysanthemum that employ plant volatiles to select host plants and ingest cell contents to probe host quality before engaging in prolonged feeding and reproduction. Changes in volatile and nonvolatile metabolite profiles can disrupt aphid-plant interactions and provide new methods of pest control. Chrysanthemol synthase (CHS) from Tanacetum cinerariifolium represents the first committed step in the biosynthesis of pyrethrin ester insecticides, but no biological role for the chrysanthemol product alone has yet been documented. In this study, the TcCHS gene was over-expressed in Chrysanthemum morifolium and resulted in both the emission of volatile chrysanthemol (ca. 47 pmol/h/gFW) and accumulation of a chrysanthemol glycoside derivative, identified by NMR as chrysanthemyl-6-O-malonyl-β-D-glucopyranoside (ca. 1.1 mM), with no detrimental phenotypic effects. Dual-choice assays separately assaying these compounds in pure form and as part of the headspace and extract demonstrated independent bioactivity of both components against the cotton aphid (Aphis gossypii). Performance assays showed that the TcCHS plants significantly reduced aphid reproduction, consistent with disturbance of aphid probing activities on these plants as revealed by electropenetrogram (EPG) studies. In open-field trials, aphid population development was very strongly impaired demonstrating the robustness and high impact of the trait. The results suggest that expression of the TcCHS gene induces a dual defence system, with both repellence by chrysanthemol odour and deterrence by its nonvolatile glycoside, introducing a promising new option for engineering aphid control into plants.
    SIEVE ELEMENT-LINING CHAPERONE1 restricts aphid feeding on arabidopsis during heat stress
    Kloth, Karen J. ; Busscher-Lange, Jacqueline ; Wiegers, Gerrie L. ; Kruijer, Willem ; Buijs, Gonda ; Meyer, Rhonda C. ; Albrectsen, Benedicte R. ; Bouwmeester, Harro J. ; Dicke, Marcel ; Jongsma, Maarten A. - \ 2017
    The Plant Cell 29 (2017)10. - ISSN 1040-4651 - p. 2450 - 2464.
    The role of phloem proteins in plant resistance to aphids is still largely elusive. By genome-wide association mapping of aphid behavior on 350 natural Arabidopsis thaliana accessions, we identified the small heat shock-like SIEVE ELEMENT-LINING CHAPERONE1 (SLI1). Detailed behavioral studies on near-isogenic and knockout lines showed that SLI1 impairs phloem feeding. Depending on the haplotype, aphids displayed a different duration of salivation in the phloem. On sli1 mutants, aphids prolonged their feeding sessions and ingested phloem at a higher rate than on wild-type plants. The largest phenotypic effects were observed at 26°C, when SLI1 expression is upregulated. At this moderately high temperature, sli1 mutants suffered from retarded elongation of the inflorescence and impaired silique development. Fluorescent reporter fusions showed that SLI1 is confined to the margins of sieve elements where it lines the parietal layer and colocalizes in spherical bodies around mitochondria. This localization pattern is reminiscent of the clamp-like structures observed in previous ultrastructural studies of the phloem and shows that the parietal phloem layer plays an important role in plant resistance to aphids and heat stress.
    Biosynthesis, localization and ecological role of pyrethrins and linked secondary metabolites in pyrethrum
    Jongsma, M.A. ; Ramirez, A. - \ 2017
    In: 2nd International Symposium on Pyrethrum International Society for Horticultural Science (Acta Horticulturae ) - ISBN 9789462611658 - p. 101 - 111.
    The perennial herbaceous plant Tanacetum cinerariifolium, also known as pyrethrum, is a daisy-like flower with an inherent ability to produce considerable amounts of biologically active metabolites, especially pyrethrins, probably intended for self-defence. The discovery of pyrethrin toxicity towards insect pests triggered the exploitation of pyrethrum for commercial purposes in the late 19th century. Despite having a long history of safe and effective use as a source of a versatile botanical insecticide, pyrethrum lost its popularity when, in the mid-20th century, more cost-effective, active and persistent synthetic variants became available. In recent years, a shift in general consumer preferences towards more selective, safer, non-persistent and more environment-friendly pesticides has renewed interest in the use of pyrethrum, renewing pyrethrum's economic significance. Despite the fact that the plant has been under commercial cultivation in many parts of the world for the last 160 years, surprisingly little breeding, ecological and genetic work has been performed to achieve important economic targets of the industry. Increasing the yield of pyrethrins in its natural host, or the mass production of pyrethrins in cultured cells or even a microbial host, would offer new possibilities to the pyrethrin industry that could potentially contribute to placing pyrethrins in a more favourable competitive position in today's insecticide market. Similarly, insights into the biological role of secondary metabolites found in pyrethrum could potentially greatly benefit the economics of the pyrethrum industry. However, in an era in which advanced breeding and genetic modification techniques are not the limiting factor, the lack of basic biochemical information, such as the identification and isolation of key enzymes involved in the formation of pyrethrins and sesquiterpene lactones, constitutes the major hurdle in the genetic engineering of these secondary metabolites, in either the natural host or other species. Genes encoding enzymes involved in the biosynthesis of certain metabolites are expected to be actively transcribed at specific moments and/or specific tissues; hence, the determination of the exact site of accumulation and synthesis of secondary metabolites constitutes a necessary tool to help pick out genes of interest. Developing knowledge around different aspects of pyrethrum secondary metabolism will, therefore, contribute to generating the necessary tools for breeding and/or engineering of varieties with enhanced pyrethrin content and decreased content of unwanted metabolites. Potentially, in the longer run, it will also be possible to engineer the biosynthesis of pyrethrins into other crop species. Ideally, such crops would then no longer require the external application of pesticides to protect them against microbial diseases and pests. Here, we will discuss the most important findings obtained in our lab, ranging from localization and biochemical aspects of the synthesis of pyrethrum defence compounds to their possible biological role in the young emerging seedling as well as in the adult plant.
    Identification of a drimenol synthase and drimenol oxidase from Persicaria hydropiper, involved in the biosynthesis of insect deterrent drimanes
    Henquet, M.G.L. ; Prota, N. ; Hooft, J.J.J. van der; Varbanova, M. ; Hulzink, R.J.M. ; Vos, M. de; Prins, M. ; Both, M.T.J. de; Franssen, M.C.R. ; Bouwmeester, H.J. ; Jongsma, M.A. - \ 2017
    The Plant Journal 90 (2017)6. - ISSN 0960-7412 - p. 1052 - 1063.
    The sesquiterpenoid polygodial, belonging to the drimane family, has been shown to be an antifeedant for a number of herbivorous insects. It is presumed to be synthesized from farnesyl diphosphate via drimenol, subsequent C-12 hydroxylation, and further oxidations at both C-11 and C-12 to form a dialdehyde. Here, we have identified a drimenol synthase (PhDS) and a cytochrome P450 drimenol oxidase (PhDOX1) from Persicaria hydropiper. Expression of PhDS in yeast and plants resulted in production of drimenol only. Co-expression of PhDS with PhDOX1 in yeast yielded drimendiol, the 12-hydroxylation product of drimenol, as a major product, and cinnamolide. When PhDS and PhDOX1 were transiently expressed by agro-infiltration in Nicotiana benthamiana leaves, drimenol was almost completely converted into cinnamolide and several additional drimenol derivatives were observed. In vitro assays showed that PhDOX1 only catalyzes the conversion from drimenol to drimendiol, and not the further oxidation into an aldehyde. In yeast and heterologous plant hosts, the C-12 position of drimendiol is therefore likely further oxidized by endogenous enzymes into an aldehyde and subsequently converted to cinnamolide, presumably by spontaneous hemiacetal formation with the C-11 hydroxyl group followed by oxidation. Purified cinnamolide was confirmed by NMR and shown to be deterrent with an effective deterrent dose (ED50 ) of ~200-400 μg gFW-1 against both whiteflies and aphids. The putative additional physiological and biochemical requirements for polygodial biosynthesis and stable storage in plant tissues are discussed
    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.