灰飞虱mucin-like基因全长cDNA的克隆及序列分析

昆虫肠黏蛋白(Insect intestinal mucin)是围食膜的重要组成部分,具有保护昆虫消化道免受病原物侵染的作用,同时也是昆虫生物防治的潜在靶标.获取灰飞虱肠黏蛋白基因对研究其基因功能及开发灰飞虱生物防治新靶标具有重要意义.该研究根据灰飞虱mucin-like基因片段(GenBank登录号:AY578090)设计特异性引物,采用RACE方法克隆获取了灰飞虱mucin-like基因cDNA全长序列(GenBank登录号为JF502033).核酸序列分析显示:该基因全长2315bp,开放阅读框为2175bp,编码725个氨基酸,在poly(A)末端上游有1个典型的多聚腺苷酸信号序列AATAAA.根据cDNA序列推导的氨基酸序列分析结果表明,该序列具有5’端信号肽,但不含有O联糖基化位点和几丁质结合域.序列比对表明该基因与其他昆虫的肠黏蛋白基因没有明显的同源性,推测其是一种新的昆虫肠黏蛋白基因.     

六偏磷酸钠对魔芋葡甘聚糖干法改性研究

用六偏磷酸钠对魔芋葡甘聚糖进行干法改性。结果表明,反应最佳条件为六偏磷酸钠：魔芋葡甘聚糖＝１：８（Ｗ／Ｗ）,在ｐＨ１,５５℃反应１．５ｈ。其透明度,粘度,冻融稳定性均比对照明显改善;水溶胶具有一定的耐酸、耐高温能力,具有相当的抑菌效果。     

性格双重性与性别二元对立的消解——论《查特莱夫人的情人》

《查特莱夫人的情人》是劳伦斯探讨男女两性关系的一部重要小说, 小说通过描写男女主人公的完美结合表达了他两性理论中理想的男女关系。本文力图展现这种人物性格的双重性, 分析这种双重性的塑造消解了性别的二元对立, 从而达到了这种理想的两性平衡关系。     

江西阳际峰自然保护区土壤的微生物学性状

研究阳际峰自然保护区不同海拔梯度土壤剖面状况及其微生物学性状,探讨土壤微生物量C与N、酶活性、微生物商与呼吸速率的变化及其相互关系。结果发现,不同海拔梯度土壤在微生物学性状上均有较大差异。总的趋势是植被覆盖度高,地形平缓,土层厚,微生物活性强,且与海拔梯度呈显著正相关。在剖面分布上,也有明显的层次差异,即随土层的增加而减少。     

Factors affecting toxicity of ferulate towards the cyanobacterium Oscillatoria cf chalybea

The objectives of this study were to determine the effect of ferulate and its analogs, and factors which may affect the toxicity of ferulate to Oscillatoria cf chalybea, the cyanobacterium presumed to cause musty flavor in farm-raised catfish. Rapid bioassays utilizing 96-well and six-well cell culture plates were used to monitor the toxicity of ferulate analogs and potential ferulate stability factors toward O cf chalybea. The additions of low concentrations of the oxidizing compound sodium carbonate peroxyhydrate with ferulate did not help control O cf. chalybea. Of three forms of ferulate tested, trans-ferulate was most toxic towards O cf chalybea. Light enhanced the toxicity of ferulate, indicating that weather conditions and the time of day could influence the success of ferulate applications to fish ponds to control O cf chalybea. Ferulate was less toxic to O cf chalybea in six-well culture plates than in 96-well plates, indicating that higher concentrations of ferulate should be used in field trials, due to possible reduction of ferulate toxicity towards O cf chalybea in large, aquatic environments (ie fish ponds). These studies provided fundamental information on potential ferulate toxicity towards O cf chalybea to be considered before conducting field trials (ferulate applications to fish ponds). © 1999 Society of Chemical Industry     

Effect of lipoic acid on redox regulation,digestive and absorptive function in intestine of mice fed high fat diet

AIM:To elucidate the molecular mechanisms of lipoic acid (LA) on redox regulation and digestive function in intestine of C57BL/6 mice fed high fat diet (HFD).METHODS:C57BL/6 mice were randomly assigned to one of three groups (n=8).The control group consumed an ordinary diet.The other two experimental groups were fed with a high fat diet, high fat plus 0.1% LA.After 6 weeks, the activities of digestive enzymes were examined.In order to evaluate the antioxidant status of the mice, superoxide dismutase (SOD), malondialdehyde (MDA), total antioxidant capacity (TAC) and reactive oxygen species (ROS) in intestinal homogenate were measured.To investigate the molecular mechanisms underlying the effects of LA, the gene expression profiles in intestine were examined using the GeneChip microarray system.RESULTS:A depressed antioxidant defense system, accompanied by digestive and absorptive function impairment, was observed in HFD-fed mice.These changes were partially restored in the LA-treated group.DNA microarray analysis of intestine showed that LA ingestion up-regulated the expression of genes related to free-radical scavenger enzymes, digestive enzymes and transporters.CONCLUSION:Treatment with LA improves redox homeostasis and the function of intestine in mice fed HFD.The mechanism may involve preventing oxidative stress by scavenging ROS directly and increasing those of free-radical scavenger enzymes gene expression indirectly.     

The EFSA quantitative approach to pest risk assessment – methodological aspects and case studies

A new method for pest risk assessment and the identification and evaluation of risk‐reducing options is currently under development by the European Food Safety Authority (EFSA) Plant Health Panel. The draft method has been tested on pests of concern to the European Union (EU). The method is adaptable and can focus either on all the steps and sub‐steps of the assessment process or on specific parts if necessary. It is based on assessing changes in pest population abundance as the major driver of the impact on cultivated plants and on the environment. Like other pest risk assessment systems the method asks questions about the likelihood and magnitude of factors that contribute to risk. Responses can be based on data or expert judgment. Crucially, the approach is quantitative, and it captures uncertainty through the provision by risk assessors of quantile estimates of the probability distributions for the assessed variables and parameters. The assessment is based on comparisons between different scenarios, and the method integrates risk‐reducing options where they apply to a scenario, for example current regulation against a scenario where risk‐reducing options are not applied. A strategy has been developed to communicate the results of the risk assessment in a clear, comparable and transparent way, with the aim of providing the requestor of the risk assessment with a useful answer to the question(s) posed to the EFSA Plant Health Panel. The method has been applied to four case studies, two fungi, Ceratocystis platani and Cryphonectria parasitica, the nematode Ditylenchus destructor and the Grapevine flavescence dorée phytoplasma. Selected results from these case studies illustrate the types of output that the method can deliver.     

低覆盖度柠条固沙林不同配置对植被修复的影响

低覆盖度行带式固沙林具有显著的防风固沙效果,已经在我国的半干旱地区广泛推广。针对内蒙古自治区呼和浩特市和林格尔县不同配置的柠条锦鸡儿人工林,进一步研究不同带间宽度带内植被自然恢复过程及物种多样性的差异,结果表明:(1)在覆盖度为20%左右时,合理的行带式格局分布的柠条锦鸡儿人工林带间植被的恢复效果优于随机分布格局的样地。(2)柠条行带式造林不宜太窄和盖度太大,会影响其林下物种丰富度。(3)宽的带间距带内物种丰富度与物种多样性和均匀度以及其生物量变化曲线呈现了两个高峰,出现在距柠条带6-8m左右,而窄的带间距带内只有一个高峰。因此,该地区柠条带宽度为12m-16m可以使其带内的草本物种多样性和生物量达到最大。     

How does the Emerald Ash Borer (Agrilus planipennis) affect ecosystem services and biodiversity components in invaded areas?

Environmental risk assessment (ERA) is an important component of risk analysis for plant pests and invasive alien species (IAS), and a standardized and consistent methodology has recently been developed for evaluating their impact on ecosystem services and biodiversity. This paper presents the application of this innovative methodology for ERA to Agrilus planipennis, the emerald ash borer, which causes significant mortality to Fraxinus (ash) species in forests and urban areas of North America (here: USA and Canada, excluding Mexico) and Russia. The methodology follows a retrospective analysis and summarizes information and observations in invaded areas in North America and Russia. Uncertainty distributions were elicited to define quantitatively a general pattern of the environmental impact in terms of reduction in ecosystem provisioning, supporting and regulating services, and biodiversity components. The environmental impacts of A. planipennis are time‐ and context‐dependent, therefore two time horizons of 5 and 20 years after introduction and two ecosystems (urban and forest) were considered. This case study shows that the quantitative assessment of environmental impacts for IAS is both possible and helpful for decision‐makers and risk managers who have to balance control costs against potential impacts of IAS.     

Socio-spatial organization reveals paternity and low kinship in the Honduran white bat (Ectophylla alba) in Costa Rica

Ectophylla alba is a tent-making bat that roosts in mixed-sex clusters comprising adults and offspring. Our goal was to determine the genetic identity of individuals belonging to different roosting groups. We tested the hypothesis of kin selection as a major force structuring group composition. We used 9 microsatellites designed for E. alba to determine the genetic identity and probability of parentage of individuals. We analyzed parentage and kinship using the software ML-Relate, GenAIEx, and Cervus. The obtained relationship probabilities (0.5) revealed a clear maternal relationship between female adults and offspring with allele compatibility, and at least 5 relationships between male adults and pups. We found a low degree of relatedness within roosting groups. Between roosting groups at different sites, the mean probability of a half-sibling relationship ranged from 0.214 to 0.244 and, for full-sibling relationship, from 0.383 to 0.553. Genetically, adult individuals were poorly related within clusters, and kinship as an evolutionary force could not explain group membership.