Size-dependent mating strategies and the risk of cannibalism

The role of sexual selection in determining the nature and direction of sexual size dimorphism may depend upon the timing of sexual selection, and this may also influence the variation in male size. For example, selection through sperm competition favours smaller males in the highly sexually size dimorphic orb-weaving spider Nephila edulis , whereas larger males are better able to exclude their smaller rivals from the central hub of the web where mating takes place. We investigate experimentally the role of body size and hub tenure in determining male fertilization success when males of different sizes compete for a single female over a 24-h period that includes a period of darkness. Our results confirm that small and large males obtain similar paternity share but that, in contrast with previous studies, hub tenure does not translate into greater paternity share. Unexpectedly, smaller males are at greater risk of postmating sexual cannibalism than larger males, suggesting that natural selection through sexual cannibalism may place a lower limit on male size.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 355–363.     

大兴安岭南部山地苔藓植物区系多样性研究

于2009～2012年对大兴安岭南部山地6个自然保护区的苔藓植物进行了野外实地调查,对所采集的1 800余号标本进行室内分析鉴定,并计算分析其种类组成、区系地理成分、地区之间相似性系数和相异系数的欧氏距离比较,及其8种生境中苔藓植物多样性指数、丰富度指数、均匀度指数和优势度指数等,为保护区的管理和建设提供基础资料。结果表明:(1)大兴安岭南部山地6个自然保护区共有苔藓植物48科,134属,330种,其中苔类16科,21属,38种,1变种;藓类32科,113属,274种,14变种,2变型,1亚种。(2)首次发现中国新记录4种:长柄紫萼藓(Grimmia longirostris Hook.),毛尖连轴藓[Schistidium lancifolium(Kindb.)Blom.],平叶真藓(Bryumlaevifilum Syed.),凹叶毛灰藓[Homomallium adnatum(Hedw.)Broth.],首次发现本地区新记录12种。(3)以丛藓科为代表的旱生藓类在本区占有优势地位;区系地理成分以温带成分(60.79%)和东亚成分(16.19%)为主。(4)大兴安岭南部山地与兴安北部和燕山北部山地亲缘关系较近;生境条件的变化对苔藓植物多样性产生了一定的影响,湿润土生和石生生境为本区苔藓植物最丰富的生境,水生生境中苔藓植物分布最少。研究发现,大兴安岭南部山地苔藓植物区系是连接华北区、东北区、蒙新区和阴山地区的过渡性地带;与燕山北部和兴安北部相比,大兴安岭南部山地大面积苔藓植物地被层分布较少的主要原因是森林密度和湿度较低。因此,建立保护区对保护大兴安岭南部山地脆弱的森林、草原过渡生态系统,保护中国野生动植物类群及其他珍稀动植物的繁衍均具有十分重要的意义。     

未净化Z：ZCLA长爪沙鼠封闭群繁育及遗传稳定性分析

目的分析未净化Z：ZCLA长爪沙鼠封闭群繁育和生长指标,并利用直接测序法分析其遗传稳定性。方法随机选择40对Z：ZCLA长爪沙鼠,记录其繁殖胎次、产子数等指标,分析其仔鼠的生长发育情况。遗传稳定性分析选择Z：ZCLA长爪沙鼠非同胞、非亲代个体33只,提取肝脏基因组DNA,PCR扩增D-Loop序列,产物纯化后双向测序,测序结果与Z：ZCLA长爪沙鼠标准序列比对。结果 Z：ZCLA长爪沙鼠每胎产仔7只,胎间隔多在20～60 d间,雄性体重高于雌性。遗传稳定性分析检测发现33只Z：ZCLA长爪沙鼠序列与标准序列完全一致。结论 Z：ZCLA长爪沙鼠群体内未发现遗传多态性,说明该群体具有较好的遗传稳定性。     

The Deuterator: software for the determination of backbone amide deuterium levels from H/D exchange MS data

Background  

The combination of mass spectrometry and solution phase amide hydrogen/deuterium exchange (H/D exchange) experiments is an effective method for characterizing protein dynamics, and protein-protein or protein-ligand interactions. Despite methodological advancements and improvements in instrumentation and automation, data analysis and display remains a tedious process. The factors that contribute to this bottleneck are the large number of data points produced in a typical experiment, each requiring manual curation and validation, and then calculation of the level of backbone amide exchange. Tools have become available that address some of these issues, but lack sufficient integration, functionality, and accessibility required to address the needs of the H/D exchange community. To date there is no software for the analysis of H/D exchange data that comprehensively addresses these issues.     

Prevalence of risk factors for cardiovascular disease in Canadians 55 to 74 years of age: results from the Canadian Heart Health Surveys, 1986-1992

BACKGROUND: By 2016, the proportion of Canadians older than 65 years of age will increase to 16%, and there will be an increase in the absolute number of cases of cardiovascular disease in older Canadians. The Canadian Heart Health Surveys database provides information about this population upon which health policy related to cardiovascular disease can be based. This paper presents for the first time population-based data on the risk factors for cardiovascular disease in older Canadians. METHODS: Canadians from all 10 provinces participated in surveys of cardiovascular risk factors; health insurance registries were used as sampling frames. In each province, probability samples of 2200 adults 18 to 74 years old not living in institutions, on reserves or in military camps were asked to participate in interviews and to undergo testing at clinics for major risk factors for cardiovascular disease. RESULTS: A total of 2739 men (response rate 70%) and 2617 women (response rate 66%) aged 55 to 74 years participated in the survey and also provided follow-up clinical measurements at the clinic. Overall, 52% of participants were hypertensive, 26% had isolated systolic hypertension, and 30% had a total blood cholesterol level of 6.2 mmol/L or greater. Rates of current smoking were lower in women than men (17% v. 22%). Overall, 87% of men and 78% of women who were current smokers smoked at least 10 cigarettes per day. Only slightly more than half of participants exercised at least once a week for at least 15 minutes, and almost half had a body mass index of 27 or greater. In only 4% was no major risk factor for cardiovascular disease detected. INTERPRETATION: Significant numbers of older Canadians have one or more major risk factors for cardiovascular disease. Many of these risk factors are amenable to modification.     

高通量扩增子测序分析生防细菌对丹参根际和根表土壤真菌群落多样性的影响

利用高量测序方法探究生防细菌对丹参植株根际和根表土壤真菌群落多样性的影响。

向丹参植株根部施入生防细菌DS-R5,培养45 d后采集根际和根表土壤样品提取总DNA,扩增样品基因组DNA的V4―V5区后进行双端测序,利用生物信息学解析生防细菌对丹参植株根际和根表土壤真菌群落多样性的影响。

菌株DS-R5处理后增加了根际和根表土壤真菌群落的多样性和丰度;根际土壤共有物种种类大于根表土壤,说明菌株DS-R5处理后根际土壤处理与对照物种种类更接近,而对根表土壤中的微生物物种影响较大。真菌群落结构组成分析结果表明,不同土壤样品在门水平上共有优势真菌主要有子囊菌门、接合菌门、担子菌门和未分类;相比根表土壤对照样品,根表土壤处理样品中子囊菌门丰度下降了13.0%,接合菌门丰度升高了69.2%;根际土壤处理样品相比根际土壤对照样品,子囊菌门和接合菌门丰度分别升高了5.9%和8.9%,但二者差异无统计学意义。在属水平上,根表土壤样品经菌株DS-R5处理后提高了有益菌属的丰度,同时降低了有害菌属的丰度。

丹参植株施入生防细菌后,改变了根际土壤和根表土壤中微生物群落结构和多样性,本研究结果可以为利用生防细菌防控丹参根腐病提供理论参考。