Records 1 - 20 / 338
FOODSECURE Scenario Driver Database
Dijk, Michiel van; Gramberger, M. ; Laborde, D. ; Mandryk, Maryia ; Shutes, Lindsay ; Stehfest, Elke ; Valin, H. ; Zellmer, K. - \ 2019
Wageningen University & Research
food security - scenarios - drivers - population - yield - gdp - gross domestic product - storylines
The FOODSECURE Scenario Driver Database contains projections for key drivers that, in combination with storylines, describe four scenarios for the assessment of global food security. The database provides information for 19 regions that together have global coverage for the period 2010-2050.
Dynamics of adaptation in experimental yeast populations exposed to gradual and abrupt change in heavy metal concentration
Gorter, Florien ; Aarts, Mark ; Zwaan, B.J. ; Visser, J.A.G.M. de - \ 2015
adaptation - ecology - evolutionary - microbial - Environmental variability - evolution - fitness - genetics - population - dynamics - fungi - heavy metals - pleiotropy
Directional environmental change is a ubiquitous phenomenon that may have profound effects on all living organisms. However, it is unclear how different rates of such change affect the dynamics and outcome of evolution. We studied this question using experimental evolution of heavy metal tolerance in the baker´s yeast Saccharomyces cerevisiae. To this end, we grew replicate lines of yeast for 500 generations in the presence of (i) a constant high concentration of cadmium, nickel or zinc, or (ii) a gradually increasing concentration of these metals. We found that gradual environmental change leads to a delay in fitness increase compared to abrupt change, but not necessarily to a different fitness of evolutionary endpoints. For the non-essential metal cadmium this delay is due to reduced fitness differences between genotypes at low metal concentrations, consistent with directional selection to minimize intracellular concentrations of this metal. In contrast, for the essential metals nickel and zinc different genotypes are selected at different concentrations, consistent with stabilizing selection to maintain constant intracellular concentrations of these metals. These findings indicate diverse fitness consequences of evolved tolerance mechanisms for essential and non-essential metals, and imply that the rate of environmental change and the nature of the stressor are crucial determinants of evolutionary dynamics.
Cell kinetics during regeneration in the sponge Halisarca caerulea: how local is the response to tissue damage?
Alexander, B.E. ; Achlatis, M. ; Osinga, R. ; Geest, H.G. van der; Cleutjens, J.P.M. ; Schutte, B. ; Goeij, J.M. de - \ 2015
PeerJ 3 (2015). - ISSN 2167-8359
coral-reef sponges - morphological strategies - sublittoral demosponge - chemical defenses - cycle checkpoints - gene-expression - life-history - trade-off - growth - population
Sponges have a remarkable capacity to rapidly regenerate in response to wound infliction. In addition, sponges rapidly renew their filter systems (choanocytes) to maintain a healthy population of cells. This study describes the cell kinetics of choanocytes in the encrusting reef sponge Halisarca caerulea during early regeneration (0–8 h) following experimental wound infliction. Subsequently, we investigated the spatial relationship between regeneration and cell proliferation over a six-day period directly adjacent to the wound, 1 cm, and 3 cm from the wound. Cell proliferation was determined by the incorporation of 5-bromo-2'-deoxyuridine (BrdU). We demonstrate that during early regeneration, the growth fraction of the choanocytes (i.e., the percentage of proliferative cells) adjacent to the wound is reduced (7.0 ± 2.5%) compared to steady-state, undamaged tissue (46.6 ± 2.6%), while the length of the cell cycle remained short (5.6 ± 3.4 h). The percentage of proliferative choanocytes increased over time in all areas and after six days of regeneration choanocyte proliferation rates were comparable to steady-state tissue. Tissue areas farther from the wound had higher rates of choanocyte proliferation than areas closer to the wound, indicating that more resources are demanded from tissue in the immediate vicinity of the wound. There was no difference in the number of proliferative mesohyl cells in regenerative sponges compared to steady-state sponges. Our data suggest that the production of collagen-rich wound tissue is a key process in tissue regeneration for H. caerulea, and helps to rapidly occupy the bare substratum exposed by the wound. Regeneration and choanocyte renewal are competing and negatively correlated life-history traits, both essential to the survival of sponges. The efficient allocation of limited resources to these life-history traits has enabled the ecological success and diversification of sponges.
Destructive fishing and fisheries enforcement in eastern Indonesia
Bailey, M.L. ; Sumaila, U.R. - \ 2015
Marine Ecology Progress Series 530 (2015). - ISSN 0171-8630 - p. 195 - 211.
coral-reefs - management - economics - conservation - bioeconomics - population - illegal
A simple bioeconomic leader-follower model was constructed to simulate snapper (family Lutjanidae) and grouper (family Serranidae) fisheries in Raja Ampat, Indonesia, an area of significant coral and fish biodiversity. We developed a leader-follower game, wherein the Regency government as the leader chooses an enforcement model to discourage illegal fishing. Fishers are then given a choice to fish using legal gears, such as handlines, or to fish with illegal gears, e.g. dynamite (for snapper) or cyanide (for grouper). Given prices and costs of legal and illegal fishing, the status quo simulations with no Regency enforcement result in a large amount of illegal catch throughout the 50 yr simulation, which agrees with expert opinion that destructive illegal fishing is occurring in the region. In an attempt to include ecosystem-based management principles into Raja Ampat governance, we introduce an enforcement regime in the form of detecting and punishing illegal fishing. Results suggest that current fishing practices do not account for the disproportionate ecosystem effects of destructive fishing, and that elimination of dynamite fishing may be easier for the government due to the high profitability of the live fish trade connected with cyanide fishing.
Epigenetic Basis of Morphological Variation and Phenotypic Plasticity in Arabidopsis thaliana
Kooke, R. ; Johannes, F. ; Wardenaar, R. ; Becker, F.F.M. ; Etcheverry, M. ; Colot, V. ; Vreugdenhil, D. ; Keurentjes, J.J.B. - \ 2015
The Plant Cell 27 (2015)2. - ISSN 1040-4651 - p. 337 - 348.
quantitative trait loci - dna methylation - transcription factor - qtl analysis - population - plant - inheritance - stability - evolution - performance
Epigenetics is receiving growing attention in the plant science community. Epigenetic modifications are thought to play a particularly important role in fluctuating environments. It is hypothesized that epigenetics contributes to plant phenotypic plasticity because epigenetic modifications, in contrast to DNA sequence variation, are more likely to be reversible. The population of decrease in DNA methylation 1-2 (ddm1-2)-derived epigenetic recombinant inbred lines (epiRILs) in Arabidopsis thaliana is well suited for studying this hypothesis, as DNA methylation differences are maximized and DNA sequence variation is minimized. Here, we report on the extensive heritable epigenetic variation in plant growth and morphology in neutral and saline conditions detected among the epiRILs. Plant performance, in terms of branching and leaf area, was both reduced and enhanced by different quantitative trait loci (QTLs) in the ddm1-2 inherited epigenotypes. The variation in plasticity associated significantly with certain genomic regions in which the ddm1-2 inherited epigenotypes caused an increased sensitivity to environmental changes, probably due to impaired genetic regulation in the epiRILs. Many of the QTLs for morphology and plasticity overlapped, suggesting major pleiotropic effects. These findings indicate that epigenetics contributes substantially to variation in plant growth, morphology, and plasticity, especially under stress conditions
The association between vitamin D status and parameters for bone density and quality is modified by Body Mass Index
Sohl, E. ; Jongh, R.T. de; Swart, K.M.A. ; Enneman, A.W. ; Wijngaarden, J.P. van; Dijk, S.C. van; Ham, A.C. ; Zwaluw, N.L. van der; Brouwer-Brolsma, E.M. ; Velde, N. van der; Groot, C.P.G.M. de; Velde, S.J. te; Lips, P. ; Schoor, N.M. van - \ 2015
Calcified Tissue International 96 (2015)2. - ISSN 0171-967X - p. 113 - 122.
quantitative ultrasound parameters - mineral density - postmenopausal women - d deficiency - physical performance - 25-hydroxyvitamin d - risk-assessment - older persons - population - metaanalysis
The association of vitamin D status with bone mineral density (BMD) and Quantitative Ultrasound measurements (QUS) has been inconsistent in previous studies, probably caused by moderating effects. This study explored (1) the association of vitamin D status with QUS and BMD, and (2) whether these associations were modified by body mass index (BMI), age, gender, or physical activity. Two-independent cohorts of the Longitudinal Aging Study Amsterdam (LASA-I, 1995/1996, aged =65; LASA-II, 2008/2009, aged 61–71) and baseline measurement of the B-vitamins for the prevention of osteoporotic fractures (B-PROOF) study (2008–2011, aged 65+) were used. QUS measurements [broadband ultrasound attenuation (BUA) and speed of sound (SOS)] were performed at the calcaneus in all three cohorts (N = 1,235, N = 365, N = 1319); BMD was measured by Dual X-ray absorptiometry (DXA) in B-PROOF (N = 1,162 and 1,192 for specific sites) and LASA-I (N = 492 and 503). The associations of vitamin D status with BUA and BMD were modified by BMI. Only in persons with low-to-normal BMI (
Change in Mesoherbivore Browsing Is Mediated by Elephant and Hillslope Position
Lagendijk, D.D.G. ; Thaker, M. ; Boer, W.F. de; Page, B.R. ; Prins, H.H.T. ; Slotow, R. - \ 2015
PLoS ONE 10 (2015)6. - ISSN 1932-6203 - 15 p.
kruger-national-park - loxodonta-africana - woodland regeneration - aepyceros-melampus - foraging behavior - east-africa - dry-season - savanna - herbivores - population
Elephant are considered major drivers of ecosystems, but their effects within small-scale landscape features and on other herbivores still remain unclear. Elephant impact on vegetation has been widely studied in areas where elephant have been present for many years. We therefore examined the combined effect of short-term elephant presence (<4 years) and hillslope position on tree species assemblages, resource availability, browsing intensity and soil properties. Short-term elephant presence did not affect woody species assemblages, but did affect height distribution, with greater sapling densities in elephant access areas. Overall tree and stem densities were also not affected by elephant. By contrast, slope position affected woody species assemblages, but not height distributions and densities. Variation in species assemblages was statistically best explained by levels of total cations, Zinc, sand and clay. Although elephant and mesoherbivore browsing intensities were unaffected by slope position, we found lower mesoherbivore browsing intensity on crests with high elephant browsing intensity. Thus, elephant appear to indirectly facilitate the survival of saplings, via the displacement of mesoherbivores, providing a window of opportunity for saplings to grow into taller trees. In the short-term, effects of elephant can be minor and in the opposite direction of expectation. In addition, such behavioural displacement promotes recruitment of saplings into larger height classes. The interaction between slope position and elephant effect found here is in contrast with other studies, and illustrates the importance of examining ecosystem complexity as a function of variation in species presence and topography. The absence of a direct effect of elephant on vegetation, but the presence of an effect on mesoherbivore browsing, is relevant for conservation areas especially where both herbivore groups are actively managed.
Socio-spatial organization and kin structure in ocelots from integration of camera trapping and noninvasive genetics
Rodgers, T.W. ; Giacalone, J. ; Heske, E.J. ; Janecka, J.E. ; Jansen, P.A. ; Phillips, C.A. ; Schooley, R.L. - \ 2015
Journal of Mammalogy 96 (2015)1. - ISSN 0022-2372 - p. 120 - 128.
inbreeding avoidance - resource dispersion - leopardus-pardalis - spatial structure - radiation hybrid - home-range - mammals - cat - relatedness - population
Kin selection theory predicts that under certain conditions animals will tolerate related individuals in their home ranges. We examined the relationship between spatiotemporal overlap and genetic relatedness in ocelots (Leopardus pardalis) to determine if kin selection plays a role in structuring ocelot populations. We used 3 years of camera trapping to examine the spatial organization of an ocelot population on Barro Colorado Island in Panama. We also placed camera traps on ocelot latrines to match photographs of individual ocelots with microsatellite genotypes from feces. Strengths of spatiotemporal overlap between individual ocelots were calculated using a half-weight association index based on how often individuals were photographed at the same camera within 30 days of one another. We calculated relatedness between individuals based on 11 variable microsatellite loci. Male ocelots overlapped with = 11 females, and females overlapped with = 7 males. We detected no clear evidence of strict intersexual territoriality in either sex. Mean overlap among males was more than 5 times greater than overlap among females; however, spatiotemporal overlap was strong between some female pairs. Overall, overlapping individuals were more related to one another than was the sample population as a whole, consistent with the hypothesis that kin selection influences ocelot spatial organization. This finding was driven by relatedness among overlapping females, and by relatedness among overlapping individuals of opposite sex, but not by overlapping males.
Elephant-mediated habitat modifications and changes in herbivore species assemblages in Sabi Sand, South Africa
Boer, W.F. de; Oort, J.W.A. van; Grover, M. ; Peel, M.J.S. - \ 2015
European Journal of Wildlife Research 61 (2015)4. - ISSN 1612-4642 - p. 491 - 503.
kruger-national-park - colophospermum-mopane - savanna vegetation - woodland structure - woody vegetation - competition - population - season - management - dynamics
Elephant Loxodonta africana conservation might indirectly influence the wider herbivore community structure, as elephants have the ability to significantly modify the savanna habitat. Uncertainty remains as to the consequences of these effects, as elephants might either compete with other species or facilitate foraging especially for grazers and smaller browsing species by increasing the amount of grass or the amount of browse at lower feeding heights. We studied these potential cascading effects of elephants by using 16 years of data (1992–2011) from the Sabi Sand Wildtuin, South Africa, which showed a steady increase in elephant densities from 0.12 to 2.03 elephants/km2 over this period. We demonstrate that tree densities, and browse availability at feeding heights below 2 m, decreased with increasing elephant densities, and that there was no positive effect of elephants on browse availability. The changes in elephant densities were good predictors (R 2 adj¿>¿0.50) in explaining population fluctuations of other herbivore species. The total body mass of grazers increased more than that of the browsers, shifting the community toward a grazer and megaherbivore-dominated community. An increasing density of elephants changes the composition of the herbivore community, as mesobrowsers are unable to benefit from the impact of elephants on trees, but megagrazers show strong positive responses. Hence, changes in elephant densities as a result of poaching or conservation may trigger cascading community effects. These are neglected but important consequences of (negative or positive) human impacts on elephant numbers, especially in restricted areas such as reserves and national parks.
Effect of vitamin B12 and folic acid supplementation on bone mineral density and quantitative ultrasound parameters in older people with an elevated plasma homocysteine level: B-PROOF, a randomized controlled trial
Enneman, A.W. ; Swart, K.M.A. ; Wijngaarden, J.P. van; Dijk, S.C. van; Ham, A.C. ; Brouwer-Brolsma, E.M. ; Zwaluw, N.L. van der; Dhonukshe-Rutten, R.A.M. ; Cammen, T.J.M. van der; Groot, C.P.G.M. de; Meurs, J.B.J. van; Lips, P. ; Uitterlinden, A.G. ; Zillikens, M.C. ; Schoor, N.M. van; Velde, N. van der - \ 2015
Calcified Tissue International 96 (2015)5. - ISSN 0171-967X - p. 401 - 409.
placebo-controlled trial - postmenopausal women - fracture risk - turnover markers - elderly-women - metaanalysis - association - population - folate - bmd
High plasma homocysteine (Hcy) levels are associated with increased osteoporotic fracture incidence. However, the mechanism remains unclear. We investigated the effect of Hcy-lowering vitamin B12 and folic acid treatment on bone mineral density (BMD) and calcaneal quantitative ultrasound (QUS) parameters. This randomized, double-blind, placebo-controlled trial included participants aged =65 years with plasma Hcy levels between 12 and 50 µmol/L. The intervention comprised 2-year supplementation with either a combination of 500 µg B12, 400 µg folic acid, and 600 IU vitamin D or placebo with 600 IU vitamin D only. In total, 1111 participants underwent repeated dual-energy X-ray assessment and 1165 participants underwent QUS. Femoral neck (FN) BMD, lumbar spine (LS) BMD, calcaneal broadband ultrasound attenuation (BUA), and calcaneal speed of sound (SOS) were assessed. After 2 years, FN-BMD and BUA had significantly decreased, while LS-BMD significantly increased (all p <0.01) and SOS did not change in either treatment arm. No statistically significant differences between the intervention and placebo group were present for FN-BMD (p = 0.24), LS-BMD (p = 0.16), SOS (p = 0.67), and BUA (p = 0.96). However, exploratory subgroup analyses revealed a small positive effect of the intervention on BUA at follow-up among compliant persons >80 years (estimated marginal mean 64.4 dB/MHz for the intervention group and 61.0 dB/MHz for the placebo group, p = 0.04 for difference). In conclusion, this study showed no overall effect of treatment with vitamin B12 and folic acid on BMD or QUS parameters in elderly, mildly hyperhomocysteinemic persons, but suggests a small beneficial effect on BUA in persons >80 years who were compliant in taking the supplement.
Impact of smoking and smoking cessation on cardiovascular events and mortality among older adults: meta-analysis of individual participant data from prospective cohort studies of the CHANCES consortium
Mons, U. ; Müezzinler, A. ; Gellert, C. ; Schöttker, B. ; Abnet, C.C. ; Bobak, M. ; Groot, C.P.G.M. de; Freedman, N.D. ; Jansen, E. ; Kee, F. ; Kromhout, D. ; Kuulasmaa, K. ; Laatikainen, T. - \ 2015
BMJ: British Medical Journal 350 (2015). - ISSN 0959-8138 - 12 p.
rate advancement periods - myocardial-infarction - cigarette-smoking - united-states - risk-factors - health - disease - population - stroke - women
Objective - To investigate the impact of smoking and smoking cessation on cardiovascular mortality, acute coronary events, and stroke events in people aged 60 and older, and to calculate and report risk advancement periods for cardiovascular mortality in addition to traditional epidemiological relative risk measures. Design - Individual participant meta-analysis using data from 25 cohorts participating in the CHANCES consortium. Data were harmonised, analysed separately employing Cox proportional hazard regression models, and combined by meta-analysis. Results - Overall, 503¿905 participants aged 60 and older were included in this study, of whom 37¿952 died from cardiovascular disease. Random effects meta-analysis of the association of smoking status with cardiovascular mortality yielded a summary hazard ratio of 2.07 (95% CI 1.82 to 2.36) for current smokers and 1.37 (1.25 to 1.49) for former smokers compared with never smokers. Corresponding summary estimates for risk advancement periods were 5.50 years (4.25 to 6.75) for current smokers and 2.16 years (1.38 to 2.39) for former smokers. The excess risk in smokers increased with cigarette consumption in a dose-response manner, and decreased continuously with time since smoking cessation in former smokers. Relative risk estimates for acute coronary events and for stroke events were somewhat lower than for cardiovascular mortality, but patterns were similar. Conclusions - Our study corroborates and expands evidence from previous studies in showing that smoking is a strong independent risk factor of cardiovascular events and mortality even at older age, advancing cardiovascular mortality by more than five years, and demonstrating that smoking cessation in these age groups is still beneficial in reducing the excess risk.
High natural antibody titers of indigenous chickens are related with increased hazard in confinement
Wondmeneh, E. ; Arendonk, J.A.M. van; Waaij, E.H. van der; Ducro, B.J. ; Parmentier, H.K. - \ 2015
Poultry Science 94 (2015)7. - ISSN 0032-5791 - p. 1493 - 1498.
laying hens - responses - survival - immunity - corticosterone - population - strains - stress - innate - plasma
Natural antibody (NAb) levels and survival rates were evaluated in 4 breeds of laying hens in Ethiopia: indigenous, improved indigenous, exotic layer, and crossbred. Titers of NAb isotypes IgG and IgM binding keyhole limpet hemocyanin (KLH) in serum were measured at 20, 26, 35, and 45 wk age. Repeated-measure ANOVA showed that IgG and IgM levels vary with time within each breed (P <0.05). Indigenous chickens had significantly (P <0.05) higher NAb levels at all ages. The Cox proportional hazard analysis showed increased hazard with increased levels of NAbs in the exotic layers (P <0.05). However, the reduced hazards with increased levels of NAbs were not significant in the improved indigenous and crossbred chickens. Indigenous chickens showed increased hazard with increasing levels of NAb (P > 0.05). We concluded that not only the NAb levels but also the effect of Nabs on survival vary between indigenous and improved breeds. The results indicate that NAb levels are associated with survival in elite (improved) breeds, but are associated with increased hazard in indigenous chickens.
Understanding the genetic basis of potato development using a multi-trait QTL analysis
Hurtado-Lopez, P.X. ; Tessema, B.B. ; Schnabel, S.K. ; Maliepaard, C.A. ; Linden, C.G. van der; Eilers, P.H.C. ; Jansen, J. ; Eeuwijk, F.A. van; Visser, R.G.F. - \ 2015
Euphytica 204 (2015)1. - ISSN 0014-2336 - p. 229 - 241.
solanum-tuberosum - complex traits - night temperature - linkage maps - mixed-model - loci - architecture - population - maturity - growth
Understanding the genetic basis of plant development in potato requires a proper characterization of plant morphology over time. Parameters related to different aging stages can be used to describe the developmental processes. It is attractive to map these traits simultaneously in a QTL analysis; because the power to detect a QTL will often be improved and it will be easier to identify pleiotropic QTLs. We included complex, agronomic traits together with plant development parameters in a multi-trait QTL analysis. First, the results of our analysis led to coherent insight into the genetic architecture of complex traits in potato. Secondly, QTL for parameters related to plant development were identified. Thirdly, pleiotropic regions for various types of traits were identified. Emergence, number of main stems, number of tubers and yield were explained by 9, 5, 4 and 6 QTL, respectively. These traits were measured once during the growing season. The genetic control of flowering, senescence and plant height, which were measured at regular time intervals, was explained by 9, 10 and 12 QTL, respectively. Genetic relationships between aboveground and belowground traits in potato were observed in 14 pleiotropic QTL. Some of our results suggest the presence of QTL-by-Environment interactions. Therefore, additional studies comparing development under different photoperiods are required to investigate the plasticity of the crop.
Effects of climate change on pest-parasitoid dynamics: Development of a simulation model and first results
Gebauer, K. ; Hemerik, L. ; Meyhöfer, R. - \ 2015
Journal of Plant Diseases and Protection 122 (2015)1. - ISSN 1861-3829 - p. 28 - 35.
diaeretiella-rapae hymenoptera - russian wheat aphid - diuraphis-noxia - brevicoryne-brassicae - cabbage aphid - temperature requirements - thermal requirements - braconidae - population - mintosh
The influence of predicted climatic change on agricultural pest and beneficial insect species is of high importance for growers since increasing temperatures may have a direct impact on the developmental rates of insect populations. These parameters are species-specific and result in variable reactions to climate change, potentially disrupting the synchrony of pest-parasitoid dynamics. This study investigatedthe effect of increasing temperatures caused by climatechange on the population dynamics of the mealy cabbage aphid Brevicoryne brassicae , a worldwide occurring pest species in cruciferous crops, and the endoparasitoid Diaeretiella rapae . For three vegetable growing regions in lower Saxony, the population development of both species was simulatedfor (1) the near future (2041-2050), (2) the far future (2090-2099) and (3) the reference time period (1991-2000), using an age structured simulation model including simulated temperature data. An earlier first occurrence of D. rapae in spring compared to B. brassicae was shown, however with no disruption of the synchrony between the two populations. Despite the earlier occurrence and increased population size of D. rapae in future periods, B. brassicae maximum population size also increased. Furthermore, an earlier occurrence of alate aphids during the season resulted from the model, indicating a potential need to adapt pest management.
Review on Dog Rabies Vaccination Coverage in Africa: A Question of Dog Accessibility or Cost Recovery?
Jibat, T. ; Hogeveen, H. ; Mourits, Monique C.M. - \ 2015
PLoS Neglected Tropical Diseases 9 (2015)2. - ISSN 1935-2727
canine rabies - machakos district - bite injuries - rural africa - ecology - population - chad - elimination - ndjamena - campaign
Rabies is one of the most fatal diseases in both humans and animals. A bite by a rabid dog is the main cause of human rabies in Africa. Parenteral mass dog vaccination is the most cost-effective tool to prevent rabies in humans. Our main objective was to review research articles on the parenteral dog rabies vaccination coverage in Africa. We aimed to review published research articles on percentage of dogs owned and percentage of dogs vaccinated against rabies, and on the relation between vaccination coverage and cost recovery.We followed the standard procedures of a systematic literature review resulting in a final review of 16 scientific articles. Our review results indicate that only a small percentage of African dogs is ownerless. Puppies younger than 3 months of age constitute a considerable proportion of the African dog population. There are considerably more male dogs than female dogs present within the dog population. The dog rabies parenteral vaccination coverage following a “free of charge” vaccination scheme (68%) is closer to World Health Organization recommended threshold coverage rate (70%) compared to the coverage rate achieved in “owner-charged” dog rabies vaccination schemes (18%). In conclusion, most dogs in Africa are owned and accessible for vaccination once the necessary financial arrangements have been made.
An updated conventional- and a novel GM potato late blight R gene differential set for virulence monitoring of Phytophthora infestans
Suxian Zhu, Suxian ; Vossen, J.H. ; Bergervoet-van Deelen, J.E.M. ; Nijenhuis, M.A. ; Kodde, L.P. ; Kessel, G.J.T. ; Vleeshouwers, V.G.A.A. ; Visser, R.G.F. ; Jacobsen, E. - \ 2015
Euphytica 202 (2015)2. - ISSN 0014-2336 - p. 219 - 234.
resistance genes - solanum-bulbocastanum - disease resistance - durable resistance - rxlr effectors - united-states - pathogen - population - races - diversity
Late blight is an important disease in potato that is caused by the oomycete Phytophthora infestans. In the past, Solanum demissum late blight resistance (R) genes were introgressed into cultivated potato (Solanum tuberosum). Eleven of these resistant plants were selected to characterize the virulence spectrum of individual P. infestans isolates and to monitor the dynamics of virulence in P. infestans populations. These plants are referred to as the Mastenbroek and Black differential sets. It has long been assumed that each differential plant contained one single R gene. In the current study and previous studies, however, most Mastenbroek differential plants were shown to harbor multiple R gene(s), which blurs virulence typing of late blight isolates. In order to acquire more accurate virulence profiles, we extended the Mastenbroek differential set with Solanum spp. plants harboring reduced R gene complexity and with plants containing recently identified R genes from related but different Solanum species. In addition, a differential set of ten Genetically Modified (GM) plants harboring single late blight R genes in the same genetic background (Desiree). By analyzing the virulence spectra of recently collected isolates using both newly described differential sets, we found that the GM Desiree differential set was more accurate for isolate virulence typing than the conventional (extended) differential set. Besides, the GM Desiree differential set was shown to be useful as trap plants to isolate novel P. infestans strains and to monitor virulence towards particular R genes in P. infestans populations `on site´. Legislative restrictions are, however, limiting the use of the GM Desiree differential set.
Gross changes in reconstructions of historic land cover/use for Europe between 1900 and 2010
Fuchs, R. ; Herold, M. ; Verburg, P.H. ; Clevers, J.G.P.W. ; Eberle, J. - \ 2015
Global Change Biology 21 (2015)1. - ISSN 1354-1013 - p. 299 - 313.
spatially explicit - secondary lands - use transitions - high-resolution - carbon stocks - wood-harvest - hyde 3.1 - climate - population - planet
Historic land-cover/use change is important for studies on climate change, soil carbon, and biodiversity assessments. Available reconstructions focus on the net area difference between two time steps (net changes) instead of accounting for all area gains and losses (gross changes). This leads to a serious underestimation of land-cover/use dynamics with impacts on the biogeochemical and environmental assessments based on these reconstructions. In this study, we quantified to what extent land-cover/use reconstructions underestimate land-cover/use changes in Europe for the 1900–2010 period by accounting for net changes only. We empirically analyzed available historic land-change data, quantified their uncertainty, corrected for spatial-temporal effects and identified underlying processes causing differences between gross and net changes. Gross changes varied for different land classes (largest for forest and grassland) and led to two to four times the amount of net changes. We applied the empirical results of gross change quantities in a spatially explicit reconstruction of historic land change to reconstruct gross changes for the EU27 plus Switzerland at 1 km spatial resolution between 1950 and 2010. In addition, the reconstruction was extended back to 1900 to explore the effects of accounting for gross changes on longer time scales. We created a land-change reconstruction that only accounted for net changes for comparison. Our two model outputs were compared with five commonly used global reconstructions for the same period and area. In our reconstruction, gross changes led in total to a 56% area change (ca. 0.5% yr-1) between 1900 and 2010 and cover twice the area of net changes. All global reconstructions used for comparison estimated fewer changes than our gross change reconstruction. Main land-change processes were cropland/grassland dynamics and afforestation, and also deforestation and urbanization.
Sustainable harvesting of non-timber forest products based on ecological and economic criteria
Hernandez-Barrios, J.C. ; Anten, N.P.R. ; Martinez-Ramos, M. - \ 2015
Journal of Applied Ecology 52 (2015)2. - ISSN 0021-8901 - p. 389 - 401.
lacandona rain-forest - understorey palm - extraction systems - defoliation - growth - reproduction - population - impact - leaf - exploitation
1. Harvesting of highly valuable non-timber forest products (NTFPs) has been considered a win-win strategy where local people profit while conserving forest biodiversity ecosystem services. Nevertheless the sustainability of NTFP harvesting has been debated as the nature of NTFPs harvesting regimes scale of commercialization are highly heterogeneous, few studies have evaluated the cumulative ecological economic effects of such regimes. Here we assessed the medium-term (10 years) sustainability of NTFP harvesting using Chamaedorea palm leaves a major NTFP from Mesoamerica that is highly valued in the international floral industry as a case study. 2. We used an experimental ecological study and an economic assessment to analyse the sustainability of leaf harvesting in C. ernesti-augustii. A 4-year leaf removal experiment was conducted to assess effects of increasing levels of defoliation (0%, 25%, 50%, 75%, 100% leaf removal, biannually) on palm survivorship, leaf production and leaf quality. Results of this experiment were combined with estimations of harvest economic value to make projections of the availability of leaves and profit per unit area. Finally, we determined harvesting regimes that maximize profit while maintaining medium-term viability of exploited populations. 3. Palms tolerated up to 50% chronic defoliation, but higher defoliation levels reduced survivorship, leaf production and leaf quality. In the long term, this 50% defoliation level maximized harvest volume and profit without significantly affecting palm survival and leaf quality. Our results show that harvesters face the dilemma of either maximizing short-term income leading to rapid exhaustion of stocks, or maintaining exploited populations but maximizing income in the long term. 4. Synthesis and applications. Our study shows that intermediate harvesting levels (=50% leaf removal) are needed to achieve long-term sustainability of Chamaedorea palm leaves. Results of this study have an immediate application for the amendment of the official Mexican law, which enables higher harvesting intensities of Chamaedorea leaves, and for the design of sustainable management strategies. Applications of such strategies should consider communitybased management, fair markets, regulating norms, as well as a thorough communication among stakeholders. Key-words: Chamaedorea ernesti-augustii, defoliation, Mexico, plant demography, socioecological sustainability, tropical rain forest
A weekly alternating diet between caloric restriction and medium-fat protects the liver from fatty liver development in middle-aged C57BL/6J mice
Rusli, F. ; Boekschoten, M.V. ; Zubia, A.A. ; Lute, C. ; Müller, M.R. ; Steegenga, W.T. - \ 2015
Molecular Nutrition & Food Research 59 (2015)3. - ISSN 1613-4125 - p. 533 - 543.
metabolic syndrome - insulin-resistance - small-intestine - induced obesity - adipose-tissue - life-span - disease - prevalence - population - expression
Scope : We aimed to investigate whether a novel dietary intervention consisting of an every-other-week calorie restricted diet could prevent non-alcoholic fatty liver disease (NAFLD) development induced by a medium-fat diet. Methods and results : Nine week-old male C57BL/6J mice received either a 1) control (C), 2) 30E% calorie restricted (CR), 3) medium-fat (MF; 25E% fat) or 4) intermittent (INT) diet, a diet alternating weekly between 40E% CR and an ad libitum MF diet until sacrifice at the age of 12 months. The metabolic, morphological, and molecular features of NAFLD were examined. The INT diet resulted in healthy metabolic and morphological features as displayed by the continuous CR diet: glucose tolerant, low hepatic triglyceride content, low plasma alanine aminotransferase. In contrast, the C- and MF-exposed mice with high body weight developed signs of NAFLD. However, the gene expression profiles of INT-exposed mice differed to those of CR-exposed mice and showed to be more similar with those of C- and MF-exposed mice with a comparable body weight. Conclusions : Our study reveals that the INT diet maintains metabolic health and reverses the adverse effects of the MF diet, thus effectively prevent the development of NAFLD in 12-month-old male C57BL/6J mice.
Dairy products and the risk of stroke and coronary heart disease: the Rotterdam Study
Praagman, J. ; Franco, O.H. ; Ikram, M.A. ; Soedamah-Muthu, S.S. ; Engberink, M.F. ; Rooij, F.J.A. van; Hofman, A. ; Geleijnse, J.M. - \ 2015
European Journal of Nutrition 54 (2015)6. - ISSN 1436-6207 - p. 981 - 990.
dietary-protein sources - cardiovascular-disease - consumption - population - women - cohort - food - metaanalysis - definitions - death
Purpose We examined whether consumption of total dairy and dairy subgroups was related to incident stroke and coronary heart disease (CHD) in a general older Dutch population. Methods The study involved 4,235 participants of the Rotterdam Study aged 55 and over who were free of cardiovascular disease (CVD) and diabetes at baseline (1990–1993). Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) for the intake of total dairy and dairy subgroups in relation to incident CVD events. Results Median intake of total dairy was 397 g/day, which mainly comprised low-fat dairy products (median intake of 247 g/day). During a median follow-up time of 17.3 years, 564 strokes (182 fatal) and 567 CHD events (350 fatal) occurred. Total dairy, milk, low-fat dairy, and fermented dairy were not significantly related to incident stroke or fatal stroke (p > 0.2 for upper vs. lower intake categories). High-fat dairy was significantly inversely related to fatal stroke (HR of 0.88 per 100 g/day; 95 % CI 0.79, 0.99), but not to incident stroke (HR of 0.96 per 100 g/day; 95 % CI 0.90, 1.02). Total dairy or dairy subgroups were not significantly related to incident CHD or fatal CHD (HRs between 0.98 and 1.05 per 100 g/day, all p > 0.35). Conclusions In this long-term follow-up study of older Dutch subjects, total dairy consumption or the intake of specific dairy products was not related to the occurrence of CVD events. The observed inverse association between high-fat dairy and fatal stroke warrants confirmation in other studies.