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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    Rationale and study protocol of the Physical Activity and Dietary intervention in women with OVArian cancer (PADOVA) study : A randomised controlled trial to evaluate effectiveness of a tailored exercise and dietary intervention on body composition, physical function and fatigue in women with ovarian cancer undergoing chemotherapy
    Stelten, Stephanie ; Hoedjes, Meeke ; Kenter, Gemma G. ; Kampman, Ellen ; Huijsmans, Rosalie J. ; Lonkhuijzen, Luc R.C.W. Van; Buffart, L.M. - \ 2020
    BMJ Open 10 (2020)11. - ISSN 2044-6055
    epidemiology - gynaecological oncology - nutrition & dietetics - nutritional support - rehabilitation medicine - sports medicine

    Introduction As a consequence of ovarian cancer and its treatment, many women with ovarian cancer have to deal with reduced physical function, fatigue, and loss of weight and/or muscle mass, compromising quality of life. Exercise and dietary interventions can positively influence body composition, physical fitness and function, and fatigue in patients with cancer. However, there are no data from randomised controlled trials on the effectiveness of exercise and dietary interventions in patients with ovarian cancer. Due to a complex disease trajectory, a relatively poor survival and distinct disease-induced and treatment-induced side effects, it is unclear whether exercise and dietary interventions that were shown to be feasible and effective in other types of cancer produce comparable results in patients with ovarian cancer. The aim of this article is to present the design of the multicentre randomised controlled Physical Activity and Dietary intervention in OVArian cancer trial and to describe how the exercise and dietary intervention is tailored to specific comorbidities and disease-induced and treatment-induced adverse effects in patients with ovarian cancer. Methods and analysis Adult women with primary epithelial ovarian cancer who are scheduled to undergo first-line (neo)adjuvant chemotherapy (n=122) are randomly allocated to a combined exercise and dietary intervention or a usual care control group during chemotherapy. Primary outcomes are body composition, physical function and fatigue. Outcome measures will be assessed before the start of chemotherapy, 3 weeks after completion of chemotherapy and 12 weeks later. The exercise and dietary intervention was tailored to ovarian cancer-specific comorbidities and adverse effects of ovarian cancer and its treatment following the i3-S strategy. Ethics and dissemination This study has been approved by the medical ethical committee of the Amsterdam UMC (reference: 018). Results of the study will be published in international peer-reviewed journals. Trial registration number Netherlands Trial Registry (NTR6300).

    Strain differences rather than species differences contribute to variation in associative learning ability in Nasonia
    Liefting, Maartje ; Verwoerd, Lisa ; Dekker, Myrthe L. ; Hoedjes, Katja M. ; Ellers, Jacintha - \ 2020
    Animal Behaviour 168 (2020). - ISSN 0003-3472 - p. 25 - 31.
    associative conditioning - memory retention - Nasonia giraulti - Nasonia vitripennis - performance index

    Insect species display a large range of inter- and intraspecific variation in learning and memory retention. Variation in associative learning ability has also been reported for three species in the parasitoid wasp genus Nasonia, most notably between Nasonia vitripennis and Nasonia giraulti, for which inbred isogenic strains have been established and studied intensively. We addressed the question how learning and memory of such isogenic strains compare to the phenotypes found in genetically diverse strains of these species. We recorded memory retention of both isogenic and genetically diverse strains of two species at 4–120 h after either olfactory or visual conditioning. Memory retention typically declined over time, but the pattern of decline differed consistently between strains. The isogenic N. vitripennis strain formed long-lasting (>5 days) memory, whereas the isogenic N. giraulti strain lost its memory after 48 h. Yet, genetically diverse strains of both species formed long-lasting memory. Memory retention patterns of strains were independent of sensory modality of the conditioned stimulus for all strains. These results show that there is variation for associative learning and memory within the two species, but not clear interspecies differences in memory retention. Without a better overview of the natural variation in learning abilities within a species, individual strains, especially isogenic strains with low genetic variability, are not necessarily representative of the species in general.

    Dataset Nasonia strains
    Liefting, Maartje ; Verwoerd, Lisa ; Dekker, Myrthe ; Hoedjes, Katja ; Ellers, Jacintha - \ 2020
    Zenodo
    associative conditioning - memory retention - Nasonia vitripennis - Nassonia girauli - performance index
    Distinct genomic signals of lifespan and life history evolution in response to postponed reproduction and larval diet in Drosophila
    Hoedjes, Katja M. ; Heuvel, Joost Van Den; Kapun, Martin ; Flatt, Thomas ; Zwaan, Bas - \ 2019
    University of Lausanne
    Evolution of ageing - Life History Evolution - genomics - Experimental evolution
    Reproduction and diet are two major factors controlling the physiology of aging and life history, but how they interact to affect the evolution of longevity is unknown. Moreover, while studies of large-effect mutants suggest an important role of nutrient sensing pathways in regulating aging, the genetic basis of evolutionary changes in lifespan remains poorly understood. To address these questions, we analyzed the genomes of experimentally evolved Drosophila melanogaster populations subjected to a factorial combination of two selection regimes: reproductive age (early versus postponed), and diet during the larval stage (‘low’, ‘control’, ‘high’), resulting in six treatment combinations with four replicate populations each. Selection on reproductive age consistently affected lifespan, with flies from the postponed reproduction regime having evolved a longer lifespan. In contrast, larval diet affected lifespan only in early-reproducing populations: flies adapted to the ‘low’ diet lived longer than those adapted to control diet. Here we find genomic evidence for strong independent evolutionary responses to either selection regime, as well as loci that diverged in response to both regimes, thus representing genomic interactions between the two. Overall, we find that the genomic basis of longevity is largely independent of dietary adaptation. Differentiated loci were not enriched for ‘canonical’ longevity genes, suggesting that naturally occurring genic targets of selection for longevity differ qualitatively from variants found in mutant screens. Comparing our candidate loci to those from other ‘evolve-and-resequence’ studies of longevity demonstrated significant overlap among independent experiments. This suggests that the evolution of longevity, despite its presumed complex and polygenic nature, might be to some extent convergent and predictable.
    Distinct genomic signals of lifespan and life history evolution in response to postponed reproduction and larval diet in Drosophila
    Hoedjes, Katja M. ; Heuvel, Joost Van Den; Kapun, Martin ; Keller, Laurent ; Flatt, Thomas ; Zwaan, Bas J. - \ 2019
    Evolution Letters 3 (2019)6. - ISSN 2056-3744 - p. 598 - 609.
    Reproduction and diet are two major factors controlling the physiology of aging and life history, but how they interact to affect the evolution of longevity is unknown. Moreover, although studies of large‐effect mutants suggest an important role of nutrient sensing pathways in regulating aging, the genetic basis of evolutionary changes in lifespan remains poorly understood. To address these questions, we analyzed the genomes of experimentally evolved Drosophila melanogaster populations subjected to a factorial combination of two selection regimes: reproductive age (early versus postponed), and diet during the larval stage (“low,” “control,” “high”), resulting in six treatment combinations with four replicate populations each. Selection on reproductive age consistently affected lifespan, with flies from the postponed reproduction regime having evolved a longer lifespan. In contrast, larval diet affected lifespan only in early‐reproducing populations: flies adapted to the “low” diet lived longer than those adapted to control diet. Here, we find genomic evidence for strong independent evolutionary responses to either selection regime, as well as loci that diverged in response to both regimes, thus representing genomic interactions between the two. Overall, we find that the genomic basis of longevity is largely independent of dietary adaptation. Differentiated loci were not enriched for “canonical” longevity genes, suggesting that naturally occurring genic targets of selection for longevity differ qualitatively from variants found in mutant screens. Comparing our candidate loci to those from other “evolve and resequence” studies of longevity demonstrated significant overlap among independent experiments. This suggests that the evolution of longevity, despite its presumed complex and polygenic nature, might be to some extent convergent and predictable.
    Adherence to Diet and Body Weight Recommendations among Cancer Survivors after Completion of Initial Cancer Treatment: A Systematic Review of the Literature
    Tjon-A-Joe, Sheena ; Pannekoek, Saraï ; Kampman, Ellen ; Hoedjes, Meeke - \ 2019
    Nutrition and Cancer 71 (2019)3. - ISSN 0163-5581 - p. 367 - 374.
    This systematic review of the literature aimed to 1) provide an overview of the extent to which cancer survivors adhere to diet and body weight recommendations after completion of initial treatment and 2) gain insight into characteristics associated with adherence to these recommendations. Four databases were searched for relevant papers. We included observational studies describing adherence to recommendations on body mass index (BMI), waist-to-hip ratio and waist circumference, fruit and vegetable intake, and alcohol consumption of adult (≥18 yr) cancer survivors after the completion of initial treatment (i.e. surgery, chemotherapy, and radiotherapy). Of the 2,830 articles retrieved from the database search, 12 articles were included. Adherence to the recommendation on BMI varied from 34% to 77%; adherence to the fruit and vegetable recommendation varied from 9% to 83%; and adherence to the recommendation on alcohol consumption varied from 62% to 96.8%. Adherence to waist-to-hip ratio (43%) and waist circumference recommendations (11%) was described in one study among overweight breast cancer survivors. The results of these studies generally suggest that adherence to the recommendation on alcohol intake is relatively high and that adherence to the recommendation on body weight and fruit and vegetable intake should particularly be promoted.
    Adaptation to developmental diet influences the response to selection on age at reproduction in the fruit fly
    May, Christina M. ; Heuvel, Joost van den; Doroszuk, Agnieszka ; Hoedjes, Katja M. ; Flatt, Thomas ; Zwaan, Bas J. - \ 2019
    Journal of Evolutionary Biology 32 (2019)5. - ISSN 1010-061X - p. 425 - 437.
    ageing - experimental evolution - life-history evolution - phenotypic plasticity

    Experimental evolution (EE) is a powerful tool for addressing how environmental factors influence life-history evolution. While in nature different selection pressures experienced across the lifespan shape life histories, EE studies typically apply selection pressures one at a time. Here, we assess the consequences of adaptation to three different developmental diets in combination with classical selection for early or late reproduction in the fruit fly Drosophila melanogaster. We find that the response to each selection pressure is similar to that observed when they are applied independently, but the overall magnitude of the response depends on the selection regime experienced in the other life stage. For example, adaptation to increased age at reproduction increased lifespan across all diets; however, the extent of the increase was dependent on the dietary selection regime. Similarly, adaptation to a lower calorie developmental diet led to faster development and decreased adult weight, but the magnitude of the response was dependent on the age-at-reproduction selection regime. Given that multiple selection pressures are prevalent in nature, our findings suggest that trade-offs should be considered not only among traits within an organism, but also among adaptive responses to different—sometimes conflicting—selection pressures, including across life stages.

    Data from: Selection for associative learning of color stimuli reveals correlated evolution of this learning ability across multiple stimuli and rewards.
    Liefting, Maartje ; Hoedjes, K.M. ; Lann, Cécile Le; Smid, H.M. ; Ellers, Jacintha - \ 2018
    Vrije Universiteit Amsterdam
    artificial selection - sensory modality - odour - colour - associative learning
    We are only starting to understand how variation in cognitive ability can result from local adaptations to environmental conditions. A major question in this regard is to what extent selection on cognitive ability in a specific context affects that ability in general through correlated evolution. To address this question we performed artificial selection on visual associative learning in female Nasonia vitripennis wasps. Using appetitive conditioning in which a visual stimulus was offered in association with a host reward, the ability to learn visual associations was enhanced within 10 generations of selection. To test for correlated evolution affecting this form of learning, the ability to readily form learned associations in females was also tested using an olfactory instead of a visual stimulus in the appetitive conditioning. Additionally, we assessed whether the improved associative learning ability was expressed across sexes by colour-conditioning males with a mating reward. Both females and males from the selected lines consistently demonstrated an increased associative learning ability compared to the control lines, independent of learning context or conditioned stimulus. No difference in relative volume of brain neuropils was detected between the selected and control lines.
    Selection for associative learning of color stimuli reveals correlated evolution of this learning ability across multiple stimuli and rewards
    Liefting, Maartje ; Hoedjes, Katja M. ; Lann, Cécile Le; Smid, Hans M. ; Ellers, Jacintha - \ 2018
    Evolution 72 (2018)7. - ISSN 0014-3820 - p. 1449 - 1459.
    Artificial selection - associative learning - color - Nasonia vitripennis - odor - sensory modality

    We are only starting to understand how variation in cognitive ability can result from local adaptations to environmental conditions. A major question in this regard is to what extent selection on cognitive ability in a specific context affects that ability in general through correlated evolution. To address this question, we performed artificial selection on visual associative learning in female Nasonia vitripennis wasps. Using appetitive conditioning in which a visual stimulus was offered in association with a host reward, the ability to learn visual associations was enhanced within 10 generations of selection. To test for correlated evolution affecting this form of learning, the ability to readily form learned associations in females was also tested using an olfactory instead of a visual stimulus in the appetitive conditioning. Additionally, we assessed whether the improved associative learning ability was expressed across sexes by color-conditioning males with a mating reward. Both females and males from the selected lines consistently demonstrated an increased associative learning ability compared to the control lines, independent of learning context or conditioned stimulus. No difference in relative volume of brain neuropils was detected between the selected and control lines.

    Increasing awareness and knowledge of lifestyle recommendations for cancer prevention in Lynch syndrome carriers : Randomized controlled trial
    Vrieling, A. ; Visser, A. ; Hoedjes, Meeke ; Hurks, H.M.H. ; Gómez García, E. ; Hoogerbrugge, N. ; Kampman, E. - \ 2018
    Clinical Genetics 93 (2018)1. - ISSN 0009-9163 - p. 67 - 77.
    Adherence - Awareness - Cancer prevention - Health education and promotion - Intervention - Lifestyle recommendation - Lynch syndrome

    Lynch syndrome (LS) mutation carriers may reduce their cancer risk by adhering to lifestyle recommendations for cancer prevention. This study tested the effect of providing LS mutation carriers with World Cancer Research Fund-the Netherlands (WCRF-NL) health promotion materials on awareness and knowledge of and adherence to these recommendations. In this randomized controlled trial (n=226), the intervention group (n=114) received WCRF-NL health promotion materials. All LS mutation carriers were asked to fill out questionnaires at 2 weeks before (baseline, T0) and at 2 weeks (T1) and 6 months (T2) after the intervention. Linear mixed models were performed on awareness (0-7) and knowledge (0-7) of the recommendations, and on the secondary outcomes, that is adherence, distress, cancer worry, and risk perception. Compared with the control group, the intervention group became significantly more aware (overall mean difference=1.24; 95%CI=0.82-1.67) and obtained significantly improved knowledge of the recommendations (overall mean difference=1.65; 95%CI=1.27-2.03). Differences were significantly larger for T1 (Pinteraction=.003 and ≤.001, respectively) but remained significant for T2. No effect on secondary outcomes was found. In conclusion, provision of WCRF-NL health promotion materials increases awareness and knowledge of lifestyle recommendations for cancer prevention among LS mutation carriers without causing additional distress, but does not affect adherence.

    An exploration of needs and preferences for dietary support in colorectal cancer survivors : A mixed-methods study
    Hoedjes, Meeke ; Kruif, Anja De; Mols, Floortje ; Bours, Martijn ; Beijer, Sandra ; Winkels, Renate ; Westerman, Marjan J. ; Seidell, Jaap C. ; Kampman, Ellen - \ 2017
    PLoS ONE 12 (2017)12. - ISSN 1932-6203

    Purpose To describe the proportion of colorectal cancer (CRC) survivors who perceive a need for dietary support; to examine which socio-demographic, cancer-related, and health-related characteristics are associated with this need; to explore reasons for (not) needing support; and to explore CRC survivors’ specific needs and preferences with regard to lifestyle (i.e., dietary, exercise, and/or weight management) support. Methods This mixed-methods study comprised a cross-sectional survey among 1774 Dutch CRC survivors and three focus groups (n = 16). To examine associations, logistic regression analyses were conducted. Focus groups were audio-taped, transcribed verbatim, and analyzed using a thematic approach. Results Of 1458 respondents (82%), 1198 (67.5%) were included for analyses. 17.5% reported a need for dietary support. Characteristics associated with this need were: being younger, living without a partner, having a stoma, having diabetes, and being overweight or obese. The main reason for needing support was being unable to initiate and maintain lifestyle changes without support. CRC survivors preferred receiving information soon after diagnosis to make an autonomous, informed decision on improving their lifestyle. They preferred to receive individually-tailored lifestyle support in an autonomy-supportive environment, preferably with involvement of their family and fellow-sufferers. Conclusions This study has provided knowledge on appropriate support for CRC survivors in need for dietary support to improve health outcomes by promoting adherence to lifestyle and body weight recommendations. Findings can be used to better identify CRC survivors in need for dietary support, and to tailor lifestyle support to their needs and preferences in order to promote uptake, adherence, and effectiveness.

    Improving oncology nurses' knowledge about nutrition and physical activity for cancer survivors
    Veen, Merel R. van; Hoedjes, Meeke ; Versteegen, Joline J. ; Meulengraaf-Wilhelm, Nienke van de; Kampman, Ellen ; Beijer, Sandra - \ 2017
    Oncology Nursing Forum 44 (2017)4. - ISSN 0190-535X - p. 488 - 496.
    Healthpromotion behavior - Nutrition - Patient education - Physical activity

    Purpose/Objectives: To assess what percentage of oncology nurses perceived themselves as having insuffcient knowledge to provide advice on nutrition and/or physical activity (PA), which characteristics were associated with nurses' perception, and whether the content and information sources differed among those nurses. Design: A cross-sectional study. Setting: A web-based survey among oncology nurses in the Netherlands. Sample: 355 oncology nurses provided advice on nutrition; of these, 327 provided advice on PA. Methods: From May to July 2013, oncology nurses were invited to complete an online questionnaire. Pearson's chi-squared tests and uni-and multivariate logistic regression analyses were conducted. Main Research Variables: Oncology nurses' perception of having suffcient or insuffcient knowledge to be able to provide advice on nutrition and PA, the content of the advice, and the information sources on which the advice was based. Findings: 43% of oncology nurses perceived themselves as having insuffcient knowledge to provide advice on nutrition, and 46% perceived insuffcient knowledge to provide advice on PA. Factors associated with perceiving insuffcient knowledge on nutrition were being aged younger, having lower education, and providing counseling during treatment only. Those nurses were more likely to suggest taking oral nutritional supplements or visiting a dietitian and were less likely to provide information on fluid intake. Nurses perceiving insuffcient knowledge about PA used oncology guidelines less often. Conclusions: Almost half of the oncology nurses providing advice on nutrition and PA perceived themselves as having insuffcient knowledge to be able to provide such advice. In particular, younger oncology nurses and oncology nurses with an intermediate vocational education may beneft most from education about these topics. Implications for Nursing: Educational training for oncology nurses should include nutrition and PA. Oncology nurses should collaborate with dietitians to discuss what information should be provided to patients by whom, and specifc PA advice should be provided by a physical therapist.

    Determinants of adherence to recommendations for cancer prevention among Lynch Syndrome mutation carriers : A qualitative exploration
    Visser, Annemiek ; Vrieling, Alina ; Murugesu, Laxsini ; Hoogerbrugge, Nicoline ; Kampman, Ellen ; Hoedjes, Meeke - \ 2017
    PLoS ONE 12 (2017)6. - ISSN 1932-6203 - 12 p.

    Background: Lynch Syndrome (LS) mutation carriers are at high risk for various cancer types, particularly colorectal cancer. Adherence to lifestyle and body weight recommendations for cancer prevention may lower this risk. To promote adherence to these recommendations, knowledge on determinants of adherence in LS mutation carriers is needed. Therefore, this study aimed to identify determinants of adherence to lifestyle recommendations for cancer prevention in LS mutation carriers. Methods: Five focus groups were conducted with DNA confirmed LS mutation carriers (n = 29). Transcripts were analyzed by thematic analysis, using the Health Belief Model (HBM) as a theoretical framework. Results: Tolerance of an unhealthy lifestyle because of the desire to enjoy life and avoidance of LS dominating their life were most frequently reported as important barriers of adherence to the recommendations. Most important facilitators of adherence to the recommendations were enhancement of wellbeing and intolerance of unhealthy foods due to colon surgery. Conclusions: This study provided a comprehensive overview of determinants of adherence to recommendations for cancer prevention. These determinants, of which some are typically and unique for LS mutation carriers, can be used to design a lifestyle intervention that meets the needs of LS mutation carriers.

    Toward the optimal strategy for sustained weight loss in overweight cancer survivors : a systematic review of the literature
    Hoedjes, Meeke ; Stralen, Maartje M. van; Joe, Sheena Tjon A. ; Rookus, Matti ; Leeuwen, Flora van; Michie, Susan ; Seidell, Jacob C. ; Kampman, Ellen - \ 2017
    Journal of Cancer Survivorship 11 (2017)3. - ISSN 1932-2259 - p. 360 - 385.
    Behaviour change techniques - Cancer survivors - Lifestyle intervention components - Weight loss maintenance
    Purpose: To gain more insight into the optimal strategy to achieve weight loss and weight loss maintenance in overweight and obese cancer survivors after completion of initial treatment, this systematic review aimed to provide an overview of the literature on intervention effects on weight, to describe intervention components used in effective interventions, to identify and synthesize behaviour change techniques (BCTs) and to assess the frequency with which these BCTs were used in effective interventions. Methods: Six databases were searched for original research articles describing weight changes in adult overweight cancer survivors after participation in a lifestyle intervention initiated after completion of initial treatment. Two researchers independently screened the retrieved papers and extracted BCTs using the BCT Taxonomy version 1. Results: Thirty-two papers describing 27 interventions were included. Interventions that were evaluated with a robust study design (n = 8) generally showed
    Adherence to the World Cancer Research Fund/American Institute for Cancer Research lifestyle recommendations in colorectal cancer survivors : results of the PROFILES registry
    Winkels, Renate M. ; Lee, Linde van; Beijer, Sandra ; Bours, Martijn J. ; Duijnhoven, Fränzel J.B. van; Geelen, Anouk ; Hoedjes, Meeke ; Mols, Floortje ; Vries, Jeanne de; Weijenberg, Matty P. ; Kampman, Ellen - \ 2016
    Cancer Medicine 5 (2016)9. - ISSN 2045-7634 - p. 2587 - 2595.
    Colon and rectal cancer - lifestyle recommendations - survivorship

    We examined adherence to the eight The World Cancer Research Foundation/American Institute for Cancer Research (WCRF/AICR) recommendations on diet, physical activity, and body weight among colorectal cancer survivors, and whether adherence was associated with intention to eat healthy and with the need for dietary advice. Adherence to these recommendations may putatively reduce the risk of recurrence and death. Studies on adherence to these recommendations in colorectal cancer (CRC) survivors are lacking. Adherence was assessed in a cross-sectional study among 1196 CRC survivors and could range between 0 (no adherence) and 8 points (complete adherence). Participants completed questionnaires on dietary intake, physical activity, and body weight. Prevalence Ratios were calculated to assess whether adherence to recommendations were associated with dietary intentions and needs. Twelve percentage of the survivors adhered to 6 or more recommendations; 65% had a score between >4 and 6 points; 23% scored no more than 4 points. The recommendation for to be modest with consumption of meat showed lowest adherence: 8% adhered; whereas the recommendation not to use dietary supplements showed highest adherence (75%). 18% reported a need for dietary advice, but this was not associated with adherence to recommendations. Survivors with higher adherence reported less often that they had received dietary advice, were less likely to have the intention to eat healthier, but reported more often that they had changed their diet since diagnosis. There is ample room for improvement of lifestyle recommendations in virtually all CRC survivors. A minor part of CRC survivors expressed a need for dietary advice which was not associated with adherence to the recommendations.

    Improving rainfall measurement in gauge poor regions thanks to mobile telecommunication networks
    Gosset, M. ; Kunstmann, H. ; Zougmore, F. ; Casenave, Frederic ; Leijnse, H. ; Uijlenhoet, R. ; Chwala, Christian ; Keis, Felix ; Doumounia, Ali ; Boubacar, Barry ; Kacou, Modeste ; Alpert, P. ; Messer, Hagit ; Rieckermann, Jörg ; Hoedjes, Joost - \ 2016
    Bulletin of the American Meteorological Society 97 (2016). - ISSN 0003-0007 - p. ES49 - ES51.
    rainfall - rainfall measurement - gauge poor regions - mobile telecommucation networks
    Differentially expressed genes linked to natural variation in long-term memory formation in Cotesia parasitic wasps
    Vugt, J.J.F.A. van; Hoedjes, K.M. ; Geest, H.C. van de; Schijlen, E.G.W.M. ; Vet, L.E.M. ; Smid, H.M. - \ 2015
    Frontiers in Behavioral Neuroscience 9 (2015). - ISSN 1662-5153 - 17 p.
    Even though learning and memory are universal traits in the Animal Kingdom, closely related species reveal substantial variation in learning rate and memory dynamics. To determine the genetic background of this natural variation, we studied two congeneric parasitic wasp species, Cotesia glomerata and C. rubecula, which lay their eggs in caterpillars of the large and small cabbage white butterfly. A successful egg laying event serves as an unconditioned stimulus (US) in a classical conditioning paradigm, where plant odors become associated with the encounter of a suitable host caterpillar. Depending on the host species, the number of conditioning trials and the parasitic wasp species, three different types of transcription-dependent long-term memory (LTM) and one type of transcription-independent, anesthesia-resistant memory (ARM) can be distinguished. To identify transcripts underlying these differences in memory formation, we isolated mRNA from parasitic wasp heads at three different time points between induction and consolidation of each of the four memory types, and for each sample three biological replicates, where after strand-specific paired-end 100 bp deep sequencing. Transcriptomes were assembled de novo and differential expression was determined for each memory type and time point after conditioning, compared to unconditioned wasps. Most differentially expressed (DE) genes and antisense transcripts were only DE in one of the LTM types. Among the DE genes that were DE in two or more LTM types, were many protein kinases and phosphatases, small GTPases, receptors and ion channels. Some genes were DE in opposing directions between any of the LTM memory types and ARM, suggesting that ARM in Cotesia requires the transcription of genes inhibiting LTM or vice versa. We discuss our findings in the context of neuronal functioning, including RNA splicing and transport, epigenetic regulation, neurotransmitter/peptide synthesis and antisense transcription. In conclusion, these brain transcriptomes provide candidate genes that may be involved in the observed natural variation in LTM in closely related Cotesia parasitic wasp species.
    Learning-induced gene expression in the heads of two Nasonia species that differ in long-term memory formation
    Hoedjes, K.M. ; Smid, H.M. ; Schijlen, E.G.W.M. ; Vet, L.E.M. ; Vugt, J.J.F.A. van - \ 2015
    BMC Genomics 16 (2015). - ISSN 1471-2164
    natural variation - antisense transcription - protein-synthesis - foraging success - parasitic wasps - drosophila - vitripennis - pathway - consolidation - opportunities
    Background Cellular processes underlying memory formation are evolutionary conserved, but natural variation in memory dynamics between animal species or populations is common. The genetic basis of this fascinating phenomenon is poorly understood. Closely related species of Nasonia parasitic wasps differ in long-term memory (LTM) formation: N. vitripennis will form transcription-dependent LTM after a single conditioning trial, whereas the closely-related species N. giraulti will not. Genes that were differentially expressed (DE) after conditioning in N. vitripennis, but not in N. giraulti, were identified as candidate genes that may regulate LTM formation. Results RNA was collected from heads of both species before and immediately, 4 or 24 hours after conditioning, with 3 replicates per time point. It was sequenced strand-specifically, which allows distinguishing sense from antisense transcripts and improves the quality of expression analyses. We determined conditioning-induced DE compared to naïve controls for both species. These expression patterns were then analysed with GO enrichment analyses for each species and time point, which demonstrated an enrichment of signalling-related genes immediately after conditioning in N. vitripennis only. Analyses of known LTM genes and genes with an opposing expression pattern between the two species revealed additional candidate genes for the difference in LTM formation. These include genes from various signalling cascades, including several members of the Ras and PI3 kinase signalling pathways, and glutamate receptors. Interestingly, several other known LTM genes were exclusively differentially expressed in N. giraulti, which may indicate an LTM-inhibitory mechanism. Among the DE transcripts were also antisense transcripts. Furthermore, antisense transcripts aligning to a number of known memory genes were detected, which may have a role in regulating these genes. Conclusion This study is the first to describe and compare expression patterns of both protein-coding and antisense transcripts, at different time points after conditioning, of two closely related animal species that differ in LTM formation. Several candidate genes that may regulate differences in LTM have been identified. This transcriptome analysis is a valuable resource for future in-depth studies to elucidate the role of candidate genes and antisense transcription in natural variation in LTM formation.
    Introgression study reveals two quantitative trait loci involved in interspecific variation in memory retention among Nasonia wasp species
    Hoedjes, K.M. ; Smid, H.M. ; Vet, L.E.M. ; Werren, J.H. - \ 2014
    Heredity 113 (2014). - ISSN 0018-067X - p. 542 - 550.
    long-term-memory - natural variation - parasitic wasps - learning rate - drosophila - evolution - consolidation - dynamics - pteromalidae - hymenoptera
    Genes involved in the process of memory formation have been studied intensively in model organisms; however, little is known about the mechanisms that are responsible for natural variation in memory dynamics. There is substantial variation in memory retention among closely related species in the parasitic wasp genus Nasonia. After a single olfactory conditioning trial, N. vitripennis consolidates long-term memory that lasts at least 6 days. Memory of the closely related species N. giraulti is present at 24¿h but is lost within 2 days after a single trial. The genetic basis of this interspecific difference in memory retention was studied in a backcrossing experiment in which the phenotype of N. giraulti was selected for in the background of N. vitripennis for up to five generations. A genotyping microarray revealed five regions that were retained in wasps with decreased memory retention. Independent introgressions of individual candidate regions were created using linked molecular markers and tested for memory retention. One region on chromosome 1 (spanning ~5.8¿cM) and another on chromosome 5 (spanning ~25.6¿cM) resulted in decreased memory after 72¿h, without affecting 24-h-memory retention. This phenotype was observed in both heterozygous and homozygous individuals. Transcription factor CCAAT/enhancer-binding protein and a dopamine receptor, both with a known function in memory formation, are within these genomic regions and are candidates for the regulation of memory retention. Concluding, this study demonstrates a powerful approach to study variation in memory retention and provides a basis for future research on its genetic basis.
    Unravelling reward value: the effect of host value on memory retention in Nasonia parasitic wasps
    Hoedjes, K.M. ; Kralemann, L.E.M. ; Vugt, J.J.F.A. van; Vet, L.E.M. ; Smid, H.M. - \ 2014
    Animal Behaviour 96 (2014). - ISSN 0003-3472 - p. 1 - 7.
    long-term-memory - sex-ratio - natural variation - pieris-rapae - drosophila - quality - vitripennis - succession - preference - behavior
    Learning can be instrumental in acquiring new skills or optimizing behaviour, but it is also costly in terms of energy and when maladaptive associations are formed: the balance between costs and benefits affects memory dynamics. Numerous studies have demonstrated that memory dynamics of animal species depend on the value of the reward during conditioning, even when animals are inexperienced with this reward. How an animal perceives reward value depends on a number of aspects, including the quantity or quality of the reward in terms of energy or fitness for the animal, the internal state of the animal and previous experience. The reliability of the learned association is another aspect, which can be assessed through the frequency of experiences, or through perception of inherent properties of the reward. The reward in oviposition learning of parasitic wasps is a host to parasitize. Different host species can differ in their reward value. This study focused on a specific aspect of reward value, namely host value, i.e. the number and size of emerging offspring, and tested the effect on oviposition learning in parasitic wasps of the genus Nasonia. We conditioned parasitic wasps of the species Nasonia vitripennis and Nasonia giraulti using three different host species as a reward, which differed greatly in their value as a host. However, for both parasitic wasp species, the resulting memory formation was independent of the value of the host. We discuss factors that may be responsible for this observation.
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