A Weight of Evidence Approach to the Aquatic Hazard Assessment of Bisphenoi A

Bisphenol A (BPA; 4,4-isopropylidene diphenol) is a chemical intermediate used primarily in the production of epoxy resins and polycarbonate products. BPA has been identified in surface waters and, hence, has been the subject of considerable research into its potential effects on aquatic organisms. Available literature on the aquatic toxicity of BPA was reviewed for quality against European Union TGD and Organization of Economic Cooperation and Development GLP principles. From this review, studies of suitable quality covering numerous ecologically relevant endpoints were identified to evaluate the survival, growth, and reproductive success of aquatic organisms exposed to BPA. Those studies yielded approximately 70 no observed effect concentrations (ranging from 16 to 3640 μg/L) and lowest observed effect concentrations (160 to 11,000 μg/L) that were considered in this weight of evidence assessment. Across all data, adverse effects on survival, growth, and reproduction occurred only at concentrations of 160 μg/L and above. Secondary biochemical (e.g., vitellogenin induction) and morphological (e.g., gonad histology) data provide insight into mechanisms of action, but do not correlate with apical endpoints related to survival, growth, and reproduction. Comparing the weight of the evidence of the aquatic toxicity data that showed chronic effects at 160 μg/L and higher with typical surface water concentrations in the range of 0.001 to 0.10 μg/ L, BPA is unlikely to cause adverse effects on aquatic populations or ecosystems.     

正交试验优化天麻超声波提取工艺的研究

为了优化天麻素的提取工艺,本研究采用超声法提取天麻素,以天麻素含量为指标,在单因素筛选基础上,采用正交试验优化提取工艺,选择料液比、提取次数和提取时间3个影响因素,每个因素3个水平进行正交试验。结果表明,最优提取工艺组合为:提取时间20min、料液比1∶15和提取次数2次;按照此工艺平行制备3批样品,天麻素的提取率为(0.339±0.13)%。     

Immunochromatographic assay for the detection of pseudojujubogenin glycosides

INTRODUCTION: Bacopa monnieri contains pseudojujubogenin glycosides as pharmacologically active compounds. In order to screen large numbers of plant samples for the presence of pseudojujubogenin glycosides, a rapid and simple assay system is required for application to small quantities of test materials. Immunoassays using monoclonal antibodies could be useful for the determination of small quantities of pseudojujubogenin glycosides in plant extracts. OBJECTIVE: The objective of this work was to develop a simple method for the detection of pseudojujubogenin glycosides by the immunochromatographic strip test using anti-bacopaside I monoclonal antibody. METHODOLOGY: The qualitative assay was based on a competitive immunoassay in which the detector reagent consisted of a colloidal gold particle coated with the respective anti-bacopaside I MAb. The capture reagent was a bacopaside I-human serum albumin conjugate immobilised onto a test strip membrane. RESULTS: The sample containing pseudojujubogenin glycosides and the detection reagent were incubated with the immobilised capture reagent. The glycosides in the sample competed in binding to the limited amount of antibodies in the detection reagent with the immobilised bacopaside I-HSA conjugates and, hence, positive samples showed no colour in the capture spot zone. The detection limit for the strip test was 125 ng/mL. CONCLUSION: The assay system was found to be useful as a rapid and simple screening method for the detection of pseudojujubogenin glycosides in plants.     

Cross‐sectional human immunodeficiency virus incidence estimation accounting for heterogeneity across communities

Accurate estimation of human immunodeficiency virus (HIV) incidence rates is crucial for the monitoring of HIV epidemics, the evaluation of prevention programs, and the design of prevention studies. Traditional cohort approaches to measure HIV incidence require repeatedly testing large cohorts of HIV‐uninfected individuals with an HIV diagnostic test (eg, enzyme‐linked immunosorbent assay) for long periods of time to identify new infections, which can be prohibitively costly, time‐consuming, and subject to loss to follow‐up. Cross‐sectional approaches based on the usual HIV diagnostic test and biomarkers of recent infection offer important advantages over standard cohort approaches, in terms of time, cost, and attrition. Cross‐sectional samples usually consist of individuals from different communities. However, small sample sizes limit the ability to estimate community‐specific incidence and existing methods typically ignore heterogeneity in incidence across communities. We propose a permutation test for the null hypothesis of no heterogeneity in incidence rates across communities, develop a random‐effects model to account for this heterogeneity and to estimate community‐specific incidence, and provide one way to estimate the coefficient of variation. We evaluate the performance of the proposed methods through simulation studies and apply them to the data from the National Institute of Mental Health Project ACCEPT, a phase 3 randomized controlled HIV prevention trial in Sub‐Saharan Africa, to estimate the overall and community‐specific HIV incidence rates.     

利用正交设计法对叉叶苏铁ISSR-PCR反应体系的优化研究

比较CTAB法和SDS法提取叉叶苏铁（Cycas micholitzii）的总DNA,发现CTAB法是提取叉叶苏铁总DNA的较好方法;对叉叶苏铁ISSR-PCR反应体系中的4个主要因素dNTPs,Taq DNA聚合酶,引物及Mg²⁺进行最优条件筛选;采用单因素法探讨DNA模板量、退火温度和循环次数的最佳反应条件,建立了适合于叉叶苏铁的最佳ISSR-PCR反应体系 （20 μL体系）： 1×Buffer,75 ng DNA模板,dNTPs 250 μmol·L^-1, Taq酶1.0U,引物0.2 μmol·L^-1,Mg2+ 2.5mmol·L^-1,反应程序为：94℃预变性5 min,94℃变性1 min,52℃退火1 min,72℃延伸2 min,循环40次,72℃延伸10 min,4℃保存。本研究结果为苏铁纲植物的分子生物学和分子系统学研究提供理论参考。     

Relationships between biological soil crusts,bacterial diversity and abundance,and ecosystem functioning: Insights from a semi‐arid Mediterranean environment

Questions: To what degree do biological soil crusts (BSCs), which are regulators of the soil surface boundary, influence associated microbial communities? Are these associations important to ecosystem functioning in a Mediterranean semi‐arid environment? Location: Gypsum outcrops near Belmonte del Tajo, Central Spain. Methods: We sampled a total of 45 (50 cm × 50 cm) plots, where we estimated the cover of every lichen and BSC‐forming lichen species. We also collected soil samples to estimate bacterial species richness and abundance, and to assess different surrogates of ecosystem functioning. We used path analysis to evaluate the relationships between the richness/abundance of above‐ and below‐ground species and ecosystem functioning. Results: We found that the greatest direct effect upon the ecosystem function matrix was that of the biological soil crust (BSC) richness matrix. A few bacterial species were sensitive to the lichen community, with a disproportionate effect of Collema crispum and Toninia sedifolia compared to their low abundance and frequency. The lichens Fulgensia subbracteata and Toninia spp. also had negative effects on bacteria, while Diploschistes diacapsis consistently affected sensitive bacteria, sometimes positively. Despite these results, very few of the BSC effects on ecosystem function could be ascribed to changes within the bacterial community. Conclusion: Our results suggest the primary importance of the richness of BSC‐forming lichens as drivers of small‐scale changes in ecosystem functioning. This study provides valuable insights on semi‐arid ecosystems where plant cover is spatially discontinuous and ecosystem function in plant interspaces is regulated largely by BSCs.     

口臭症口腔微生态学的研究

目的 :研究口臭症患者口腔菌群分布。方法 :选择 3 0例口臭患者和 3 0例健康人 ,分别采集舌背舌苔和牙周袋菌斑作细菌的需氧、微需氧和厌氧菌的定量培养 ,并对牙龈卟啉单胞菌及衣氏放线菌做抑菌试验。结果 :口臭组舌背厌氧菌及微需氧菌总数 (12 .2± 1.3 2 )与健康对照组 (9.5± 1.2 4)差异有非常显著性 (P<0 .0 1) ,口臭组需氧菌总数与健康组差异有显著性 (P<0 .0 5) ;口臭组牙周袋厌氧菌及微需氧菌总数 (13 .12± 1.2 6)明显高于健康对照组 (11.3± 1.82 ) ,两者差异有非常显著性 (P<0 .0 1) ,而需氧菌差异无显著性 ;口臭症舌背以小韦荣菌为主 ,其次是黑色普氏菌 ;牙周袋菌斑以牙龈卟啉单胞菌和黑色普氏菌为主 ,其次是衣氏放线菌。并筛选出两类抗菌漱口水和一种中外合资抗口臭牙膏 ,对舌背及牙周袋菌斑的主要细菌牙龈卟啉单胞菌和衣氏放线菌有明显的抑制作用。结论 :口臭症患者口腔菌群分布和总数与正常人群存在显著的差异 ,与牙周病有关的致病菌数量明显高于正常人群 ,据抑菌试验结果采用有效的漱口液及牙膏可明显降低口腔内致病菌和改善口臭症状。     

分子进化生物学中序列分析方法的新进展

简要介绍了分子进化生物学中序列分析方法的最新进展,特别强调了似然比检验和贝叶斯推论在分子进化和系统发育假说检验中的重要性,并介绍了新方法的一些成功应用,同时还给出了一些重要的信息资源。     

濒危树种格木天然群体自由授粉子代苗期生长变异

格木是我国热带和南亚热带地区主要的珍稀濒危树种之一,具有重要的经济和生态价值。本文应用从格木主要天然分布区收集的6个群体的种子进行育苗试验,揭示格木天然群体子代芽苗和幼苗生长变异状况及其与种子性状、亲本环境因子间的相关性。结果表明,格木天然群体子代芽苗和幼苗表型性状在群体间和群体内均存在丰富的变异,苗高的变异高于地径,苗期选择以高生长为主。格木苗期生长与种子的大小、千粒重相关显著,胚根长度与经度、地径与年均气温、高径比与海拔均存在显著的相关性(p＜0.05)。研究结果为深入开展格木良种选育奠定了基础,亦将有助于其天然资源的保护经营和人工种植业的发展。