Measurement on Camber Deformation of Wings of Free-flying Dragonflies and Beating-flying Dragonflies

1　IntroductionNumerouskinematicparameters,includingwing beatfrequency ,wingorientation ,andbothspan andchord wisedeformation ,arerelevanttotheaerodynam icanalysisofinsectflight[1,2 ] .Althoughnearlyalltherecentstudiesofinsectflightaerodynamics[3,4 ] haveidentifiedthatthemechanismsrequireflowseparationattheleadingedge ,andcamberisnotexpectedtohaveanysignificantinfluenceonthemagnitudeoftheforcecoefficient,someinsects ,suchasdragonfliesandbut terflies,frequently glideusinglowanglesofattack ,lead…     

Microsatellites reveal a high population structure in Triatoma infestans from Chuquisaca, Bolivia

Background

For Chagas disease, the most serious infectious disease in the Americas, effective disease control depends on elimination of vectors through spraying with insecticides. Molecular genetic research can help vector control programs by identifying and characterizing vector populations and then developing effective intervention strategies.

Methods and Findings

The population genetic structure of Triatoma infestans (Hemiptera: Reduviidae), the main vector of Chagas disease in Bolivia, was investigated using a hierarchical sampling strategy. A total of 230 adults and nymphs from 23 localities throughout the department of Chuquisaca in Southern Bolivia were analyzed at ten microsatellite loci. Population structure, estimated using analysis of molecular variance (AMOVA) to estimate F_ST (infinite alleles model) and R_ST (stepwise mutation model), was significant between western and eastern regions within Chuquisaca and between insects collected in domestic and peri-domestic habitats. Genetic differentiation at three different hierarchical geographic levels was significant, even in the case of adjacent households within a single locality (R _ST = 0.14, F _ST = 0.07). On the largest geographic scale, among five communities up to 100 km apart, R _ST = 0.12 and F _ST = 0.06. Cluster analysis combined with assignment tests identified five clusters within the five communities.

Conclusions

Some houses are colonized by insects from several genetic clusters after spraying, whereas other households are colonized predominately by insects from a single cluster. Significant population structure, measured by both R _ST and F _ST, supports the hypothesis of poor dispersal ability and/or reduced migration of T. infestans. The high degree of genetic structure at small geographic scales, inferences from cluster analysis and assignment tests, and demographic data suggest reinfesting vectors are coming from nearby and from recrudescence (hatching of eggs that were laid before insecticide spraying). Suggestions for using these results in vector control strategies are made.     

4-Aryl-2-anilinopyrimidines as corticotropin-releasing hormone (CRH) antagonists

A series of 4-aryl-2-(N-ethylanilino)pyrimidines has been synthesized as corticotropin-releasing hormone (CRH) inhibitors. The effect of substitution on each aromatic ring on receptor binding was investigated.     

High levels of auto-infection in plant pathogens favour short latent periods: a theoretical approach

Auto-infection (infection arising from inoculum produced on the same host unit) is common in polycyclic plant pathogens, but often neglected in experimental and theoretical studies, which focus instead on infection of new hosts (allo-infection). Here we test the hypothesis that high auto-infection, as observed for leaf infecting fungal pathogens, could select for short latent periods. An individual-based simulation model keeps track of lesions, resulting from the spread of spores, between and within individual leaves. Linked to a trade-off between latent period and spore production capacity, as observed for Puccinia triticina on wheat, the adaptation of the latent period is analysed for different levels of auto-infection using the methods of pairwise invasibility plots. Results suggest that increased auto-infection selects for reduced latent periods. A reduction in leaf longevity also selects for reduced latent periods, which is most obvious for a relatively low ratio of auto- to allo-infection. This study is the first to consider the effect of auto-infection on the evolution of pathogen life history traits. The fact that auto-infection could drastically reduce pathogen latent periods highlights the need for more research in this area.     

中药新药保肝作用的研究进展

肝脏作为代谢器官,在人体内发挥着重要作用。随着肝病的发病率逐年上升,如何有效的保肝护肝已成为医学界和药学界共同面一临的巨大挑战之一。化学药物在治疗肝病的同时常常伴随各种毒副作用甚至更进一步的肝损伤,而中药凭借其安全性和有效性的优势在肝病治疗领域受到越来越多的重视。中药护肝已有悠久的历史,近年来随着技术的进步,更多更好的新型中药逐步上市,相关研究不断增多。本文将就这些研究成果进行阐述。     

Cyclo(l-Pro-d-Arg): a new antibacterial and antitumour diketopiperazine from Bacillus cereus associated with a rhabditid entomopathogenic

In continuation of our search for new antimicrobial secondary metabolites from Bacillus cereus associated with rhabditid entomopathogenic nematode, a new microbial diketopiperazine, cyclo(l-Pro-d-Arg), was isolated from the ethyl acetate extract of fermented modified nutrient broth. The chemical structures of the isolated compounds were identified based on their 1D, 2D NMR and high-resolution electrospray ionisation–mass spectroscopy data. Antibacterial activity of the compound was determined by minimum inhibitory concentration and disc diffusion method against medically important bacteria, and the compound was recorded to have significant antibacterial activity against test bacteria. The highest activity was recorded against Klebsiella pneumoniae (1 μg/mL). Cyclo(l-Pro-d-Arg) was recorded to have significant antitumor activity against HeLa cells (IC₅₀ value 50 μg/mL), and this compound was recorded to have no cytotoxicity against normal monkey kidney cells (VERO) up to 100 μg/mL). To the best of our knowledge, this is the first time that cyclo(l-Pro-d-Arg) has been isolated from a microbial natural source.