Stronger diversity effects with increased environmental stress : a study of multitrophic interactions between oak, powdery mildew and ladybirds

Recent research has suggested that increasing neighbourhood tree species diversity may mitigate the impact of pests or pathogens by supporting the activities of their natural enemies and/or reducing the density of available hosts. In this study, we attempted to assess these mechanisms in a multitrophic study system of young oak (Quercus), oak powdery mildew (PM, caused by Erysiphe spp.) and a mycophagous ladybird (Psyllobora vigintiduo-punctata). We assessed ladybird mycophagy on oak PM in function of different neighbourhood tree species compositions. We also evaluated whether these species interactions were modulated by environmental conditions as suggested by the Stress Gradient Hypothesis. We adopted a complementary approach of a field experiment where we monitored oak saplings subjected to a reduced rainfall gradient in a young planted forest consisting of different tree species mixtures, as well as a lab experiment where we independently evaluated the effect of different watering treatments on PM infections and ladybird mycophagy. In the field experiment, we found effects of neighbourhood tree species richness on ladybird mycophagy becoming more positive as the target trees received less water. This effect was only found as weather conditions grew drier. In the lab experiment, we found a preference of ladybirds to graze on infected leaves from trees that received less water. We discuss potential mechanisms that might explain this preference, such as emissions of volatile leaf chemicals. Our results are in line with the expectations of the Natural Enemies Hypothesis and support the hypothesis that biodiversity effects become stronger with increased environmental stress

The emergence of the 2013 H7N9 and related viruses in China

Promising Investigator ScholarshipPoster Session: News and Views from the H7N9 OutbreakBackground: The novel H7N9 influenza A virus first detected in March 2013 has caused more than 130 cases of human infection in China, resulting in 39 deaths. This virus is a reassortant of H7, N9 and H9N2 avian influenza viruses and carries some amino acids linked to mammalian receptor binding, raising concerns of a new pandemic. However, neither the source populations of the H7N9 outbreak lineage nor the conditions for its genesis are fully understood. Materials and Methods: Following the initial reports of H7N9 influenza infection in humans, field surveillance was conducted during 4th-18th April in Zhejiang, Shandong and Guangdong provinces. Pairs of oropharyngeal and cloacal samples from chickens and other poultry, together with faecal and water samples from live poultry markets (LPMs), farms and wetlands were collected for virus isolation and whole genomic sequencing. H7, N9, N7 and H9N2 archived isolates, obtained during previous influenza surveillance between 2000-2013 in southern China, were also sequenced and phylogenetically analyzed to pinpoint the genesis of the H7N9 and a related H7N7 virus. The infectivity and pathology of H7N9 and H7N7 viruses were tested in a ferret model. Results: Through a combination of active surveillance, screening of virus archives, and evolutionary analyses, we found that H7 viruses have independently transferred from domestic ducks to chickens in China on at least two occasions. Subsequently they reassorted with enzootic H9N2 viruses to generate the H7N9 outbreak lineage, and a related but previously unrecognized H7N7 lineage. The H7N9 outbreak lineage has spread over a large geographic region and is prevalent in chickens at LPMs that appear to be the immediate source of human infections. In ferrets this virus caused a productive infection and pneumonia. Virus was shed via the nasal route and transmitted to physical contact and some airborne-exposed animals. Like the H7N9 virus, the H7N7 virus was also mainly isolated from chickens at LPMs and it could efficiently infect ferrets, be shed via the nasal and rectal routes, and cause severe pneumonia. Conclusions: These findings provide a clear picture showing how the current H7N9 human viruses emerged. Domestic ducks act as primary vectors to acquire and maintain diversified viruses from migratory birds, and facilitate different subtype combinations between H7 and N9 or N7 viruses and interspecies transmissions to chickens. After being introduced, the H7N9 or H7N7 viruses reassorted with enzootic H9N2 viruses and formed the current reassortant H7N9 or H7N7 viruses seen in chickens. This likely led to outbreaks in chickens, resulting in the rapid spread of the novel reassortant H7N9 virus through LPMs, which then became the source of human infections. Whether the H7N9 outbreak lineage will, or has, become enzootic in China needs further investigation. Our results also indicate that H7 viruses pose a broader threat than the current H7N9 virus. Continued prevalence of this family of H7 viruses in poultry could lead to further sporadic human infections, with an ongoing risk that the virus might acquire efficient human-to-human transmissibility.published_or_final_versio

Appropriate model use for predicting elevations and inundation extent for extreme flood events

Flood risk assessment is generally studied using flood simulation models; however, flood risk managers often simplify the computational process; this is called a “simplification strategy”. This study investigates the appropriateness of the “simplification strategy” when used as a flood risk assessment tool for areas prone to flash flooding. The 2004 Boscastle, UK, flash flood was selected as a case study. Three different model structures were considered in this study, including: (1) a shock-capturing model, (2) a regular ADI-type flood model and (3) a diffusion wave model, i.e. a zero-inertia approach. The key findings from this paper strongly suggest that applying the “simplification strategy” is only appropriate for flood simulations with a mild slope and over relatively smooth terrains, whereas in areas susceptible to flash flooding (i.e. steep catchments), following this strategy can lead to significantly erroneous predictions of the main parameters—particularly the peak water levels and the inundation extent. For flood risk assessment of urban areas, where the emergence of flash flooding is possible, it is shown to be necessary to incorporate shock-capturing algorithms in the solution procedure, since these algorithms prevent the formation of spurious oscillations and provide a more realistic simulation of the flood levels

Identification of storage conditions stabilizing extracellular vesicles pre

Extracellular vesicles (EVs) play a key role in many physiological and pathophysiological processes and hold great potential for therapeutic and diagnostic use. Despite significant advances within the last decade, the key issue of EV storage stability remains unresolved and under investigated. Here, we aimed to identify storage conditions stabilizing EVs and comprehensively compared the impact of various storage buffer formulations at different temperatures on EVs derived from different cellular sources for up to 2 years. EV features including concentration, diameter, surface protein profile and nucleic acid contents were assessed by complementary methods, and engineered EVs containing fluorophores or functionalized surface proteins were utilized to compare cellular uptake and ligand binding. We show that storing EVs in PBS over time leads to drastically reduced recovery particularly for pure EV samples at all temperatures tested, starting already within days. We further report that using PBS as diluent was found to result in severely reduced EV recovery rates already within minutes. Several of the tested new buffer conditions largely prevented the observed effects, the lead candidate being PBS supplemented with human albumin and trehalose (PBS-HAT). We report that PBS-HAT buffer facilitates clearly improved short-term and long-term EV preservation for samples stored at -80°C, stability throughout several freeze-thaw cycles, and drastically improved EV recovery when using a diluent for EV samples for downstream applications

Growth-Rate Dependence Reveals Design Principles of Plasmid Copy Number Control

Genetic circuits in bacteria are intimately coupled to the cellular growth rate as many parameters of gene expression are growth-rate dependent. Growth-rate dependence can be particularly pronounced for genes on plasmids; therefore the native regulatory systems of a plasmid such as its replication control system are characterized by growth-rate dependent parameters and regulator concentrations. This natural growth-rate dependent variation of regulator concentrations can be used for a quantitative analysis of the design of such regulatory systems. Here we analyze the growth-rate dependence of parameters of the copy number control system of ColE1-type plasmids in E. coli. This analysis allows us to infer the form of the control function and suggests that the Rom protein increases the sensitivity of control

Synthesis and characterisation of coating polyurethane cationomers containing fluorine built-in hard urethane segments

Polyurethane cationomers were synthesised in the reaction of 4,4’-methylenebis(phenyl isocyanate) with polyoxyethylene glycol (M = 2,000) or poly(tetrafluoroethyleneoxide-co-difluoromethylene oxide) α,ω-diisocyanate and N-methyl diethanolamine. Amine segments were built-in to the urethane-isocyanate prepolymer in the reaction with 1-bromobutane or formic acid, and then they were converted to alkylammonium cations. The obtained isocyanate prepolymers were then extended in the aqueous medium that yielded stable aqueous dispersions which were applied on the surfaces of test poly(tetrafluoroethylene) plates. After evaporation of water, the dispersions formed thin polymer coatings. 1H, 13C NMR and IR spectral methods were employed to confirm chemical structures of synthesised cationomers. Based on 1H NMR and IR spectra, the factors κ and α were calculated, which represented the polarity level of the obtained cationomers. The DSC, wide angle X-ray scattering and atom force microscopy methods were employed for the microstructural assessment of the obtained materials. Changes were discussed in the surface free energy and its components, as calculated independently according to the method suggested by van Oss–Good, in relation to chemical and physical structures of cationomers as well as morphology of coating surfaces obtained from those cationomers. Fluorine incorporated into cationomers (about 30%) contributed to lower surface free energy values, down to about 15 mJ/m2. That was caused by gradual weakening of long-range interactions within which the highest share is taken by dispersion interactions

Healthy Lifestyle Behaviour Decreasing Risks of Being Bullied, Violence and Injury

Background: Bullying and violence are problems of aggression in schools among adolescents. Basic daily healthy practices including nutritious diet, hygiene and physical activity are common approaches in comprehensive health promotion programs in school settings, however thier relationship to these aggressive behaviours is vague. We attempted to show the advantages of these healthy lifestyle behaviours in 9 developing countries by examining the association with being frequently bullied, violence and injury. Methodology/Principal Findings: A cross-sectional cross-national survey of 9 countries using the WHO Global School Based Student Health Survey dataset was used. Measurements included experiences of ‘‘being frequently bullied’ ’ in the preceding 30 days and violence/injury in the past 12 months. Association of risk behaviours (smoking, alcohol, sexual behaviour) and healthy lifestyle (nutrition, hygiene practices, physical activity) to being bullied, and violence/injury were assessed using multivariate logistic regression. Hygiene behaviour showed lower risks of being frequently bullied [male: RR = 0.7 (97.5CI: 0.5, 0.9); female: RR = 0.6 (0.5, 0.8)], and lower risk of experiences of violence/injury [RR = 0.7 (0.5, 0.9) for males], after controlling for risk behaviours, age, education, poverty, and country. Conclusion/Significance: Healthy lifestyle showed an association to decreased relative risk of being frequently bullied and violence/injury in developing countries. A comprehensive approach to risk and health promoting behaviours reducin

The role of HLA-G in human pregnancy

Pregnancy in mammals featuring hemochorial placentation introduces a major conflict with the mother's immune system, which is dedicated to repelling invaders bearing foreign DNA and RNA. Numerous and highly sophisticated strategies for preventing mothers from rejecting their genetically different fetus(es) have now been identified. These involve production of novel soluble and membrane-bound molecules by uterine and placental cells. In humans, the placenta-derived molecules include glycoproteins derived from the HLA class Ib gene, HLA-G. Isoforms of HLA-G saturate the maternal-fetal interface and circulate in mothers throughout pregnancy. Uteroplacental immune privilege for the fetus and its associated tissues is believed to result when immune cells encounter HLA-G. Unequivocally demonstration of this concept requires experiments in animal models. Both the monkey and the baboon express molecules that are similar but not identical to HLA-G, and may comprise suitable animal models for establishing a central role for these proteins in pregnancy

Genome-wide association study identifies single-nucleotide polymorphism in KCNB1 associated with left ventricular mass in humans: The HyperGEN Study

<p>Abstract</p> <p>Background</p> <p>We conducted a genome-wide association study (GWAS) and validation study for left ventricular (LV) mass in the Family Blood Pressure Program – HyperGEN population. LV mass is a sensitive predictor of cardiovascular mortality and morbidity in all genders, races, and ages. Polymorphisms of candidate genes in diverse pathways have been associated with LV mass. However, subsequent studies have often failed to replicate these associations. Genome-wide association studies have unprecedented power to identify potential genes with modest effects on left LV mass. We describe here a GWAS for LV mass in Caucasians using the Affymetrix GeneChip Human Mapping 100 k Set. Cases (N = 101) and controls (N = 101) were selected from extreme tails of the LV mass index distribution from 906 individuals in the HyperGEN study. Eleven of 12 promising (<it>Q </it>< 0.8) single-nucleotide polymorphisms (SNPs) from the genome-wide study were successfully genotyped using quantitative real time PCR in a validation study.</p> <p>Results</p> <p>Despite the relatively small sample, we identified 12 promising SNPs in the GWAS. Eleven SNPs were successfully genotyped in the validation study of 704 Caucasians and 1467 African Americans; 5 SNPs on chromosomes 5, 12, and 20 were significantly (<it>P </it>≤ 0.05) associated with LV mass after correction for multiple testing. One SNP (rs756529) is intragenic within <it>KCNB1</it>, which is dephosphorylated by calcineurin, a previously reported candidate gene for LV hypertrophy within this population.</p> <p>Conclusion</p> <p>These findings suggest <it>KCNB1 </it>may be involved in the development of LV hypertrophy in humans.</p