几种杀虫剂对南美斑潜蝇及其寄生蜂潜蝇茧蜂的毒力

测定了阿维菌素、灭蝇胺、杀虫单、毒死蜱、灭多威、顺式氯氰菊酯6种杀虫剂对南美斑潜蝇2龄幼虫、成虫及其寄生蜂潜蝇茧蜂的室内毒力,并考察了灭蝇胺、阿维菌素和杀虫单对南美斑潜蝇的田间防效。在所研究浓度下,阿维菌素、灭蝇胺对2龄幼虫的毒力较高,但对南美斑潜蝇成虫和潜蝇茧蜂的毒力较低;杀虫单对南美斑潜蝇成虫、2龄幼虫和潜蝇茧蜂的毒力均较高;毒死蜱、灭多威、顺式氯氰菊酯对南美斑潜蝇2龄幼虫的毒力较低,而对潜蝇茧蜂的毒力较高。田间条件下,灭蝇胺、阿维菌素和杀虫单都对田间南美斑潜蝇具有较高防效。     

七星瓢虫基础研究现状

七星瓢虫对蚜虫等农林业中的重要害虫有较强的控制作用,利用七星瓢虫进行控害的生物防治技术正在逐步推广.本文就七星瓢虫的生物学特性、捕食、对农药的反应以及人工饲养等方面进行综述:七星瓢虫幼虫随龄期增长逐渐出现黄斑,温湿度对生长发育影响较大,以成虫越冬,有滞育现象.七星瓢虫捕食性强,捕食对象较多,包括多种蚜虫、木虱、蚧虫、粉...     

四黄散外敷对竹叶青蛇咬伤肿胀的疗效观察

目的 探讨四黄散外敷治疗竹叶青蛇咬伤肿胀的临床疗效.方法 选择2017年10月～2020年4月我院收治的112例竹叶青蛇咬伤肿胀患者为研究对象,采用随机数字表法将患者分为观察组和对照组,每组56例.对照组采用常规蛇咬伤处理方案,包括清创、引流、注射抗蛇毒血清及对症治疗等.观察组在对照组治疗基础上采用四黄散外敷治疗.观察...     

里氏木霉产纤维素酶研究进展

木质纤维素类生物质被认为是重要且可持续的可再生能源,其主要组成部分是纤维素.纤维素酶是一种能将纤维素分解为葡萄糖的复合酶,能有效地降解木质纤维素生物质.真菌、细菌、放线菌、酵母等多种微生物均可以产生纤维素酶,其中里氏木霉具有完整的纤维素酶系结构,常作为生物技术领域中一个重要菌株,广泛应用于纤维素酶的商业生产.介绍了纤维...     

蒲桃仁提取物降血糖作用的实验研究

采用四氧嘧啶糖尿病小鼠模型及肾上腺素和葡萄糖引起的高血糖小鼠模型,观察蒲桃仁乙醇提取物对实验动物的降血糖效果。蒲桃仁乙醇提取物对四氧嘧啶所致糖尿病小鼠模型、肾上腺素和葡萄糖引起的高血糖模型小鼠有明显的降血糖作用,但对正常小鼠血糖无明显影响。     

2种中草药对福寿螺的杀灭效果及对肝脏影响

【目的】有效控制福寿螺产生的危害,为实现中草药的资源化利用提供依据。【方法】以甘草、陈皮为植物源灭螺剂,进行不同浓度梯度(0、0.5、1.5、3.0、4.5、6.0 g·L^-1)提取液浸泡下的灭螺活性探究。【结果】甘草组、陈皮组处理下福寿螺死亡率随时间的增长在不同浓度下毒杀效果明显。对48 h时福寿螺死亡率数据进行概率单位法回归分析,发现甘草组(LC₂₅、LC₅₀、LC₇₅)<陈皮组(LC₂₅、LC₅₀、LC₇₅),说明福寿螺对甘草更敏感。为进一步探究福寿螺死亡原因,在前期研究的基础上深入探讨甘草、陈皮提取液对福寿螺的肝脏的影响,在亚致死浓度甘草0.511 g·L^-1(LC₂₅)、0.940 g·L^-1(LC₅₀)、1.727 g·L^-1(LC₇₅)和陈皮3.892 g·L^-1...     

Lambda-carrageenan: A novel chiral selector for capillary electrophoresis

Lambda-carrageenan, a linear high molecular weight sulfated polysaccharide, has been employed as a chiral selector in capillary electrophoresis for the separation of enantiomers of weakly basic pharmaceutical compounds. The racemic compounds that were enantioresolved included propranolol, pindolol, tryptophanol, laudanosine and laudanosoline. In addition, the diastereomeric pair of cinchonine and cinchonidine were also resolved. Method conditions such as buffer pH, electrolyte concentration, column temperature, and chiral selector concentration were found to be important for improvement of enantioselectivity. © 1996 Wiley-Liss, Inc.     

Structural basis for the recognition of methylated histone H3 by the Arabidopsis LHP1 chromodomain

Arabidopsis LHP1 (LIKE HETEROCHROMATIN PROTEIN 1), a unique homolog of HP1 in Drosophila, plays important roles in plant development, growth, and architecture. In contrast to specific binding of the HP1 chromodomain to methylated H3K9 histone tails, the chromodomain of LHP1 has been shown to bind to both methylated H3K9 and H3K27 histone tails, and LHP1 carries out its function mainly via its interaction with these two epigenetic marks. However, the molecular mechanism for the recognition of methylated histone H3K9/27 by the LHP1 chromodomain is still unknown. In this study, we characterized the binding ability of LHP1 to histone H3K9 and H3K27 peptides and found that the chromodomain of LHP1 binds to histone H3K9me2/3 and H3K27me2/3 peptides with comparable affinities, although it exhibited no binding or weak binding to unmodified or monomethylated H3K9/K27 peptides. Our crystal structures of the LHP1 chromodomain in peptide-free and peptide-bound forms coupled with mutagenesis studies reveal that the chromodomain of LHP1 bears a slightly different chromodomain architecture and recognizes methylated H3K9 and H3K27 peptides via a hydrophobic clasp, similar to the chromodomains of human Polycomb proteins, which could not be explained only based on primary structure analysis. Our binding and structural studies of the LHP1 chromodomain illuminate a conserved ligand interaction mode between chromodomains of both animals and plants, and shed light on further functional study of the LHP1 protein.     

The group size effect and synchronization of vigilance in the Tibetan wild ass

Vigilance behavior is considered as an effective strategy for prey species to detect predators.An individual benefits from living in a group by reducing the time spent being vigilant without affecting the probability of detecting a predator.However,the mechanism producing a decrease in vigilance with increasing group size is unclear.Many models of vigilance assume that group members scan independently of one another.Yet in recent studies,the other 2 patterns of vigilance,coordination and synchronization,were reported in some species.In 2 summers(2018 and 2019),we studied the group-size effect on vigilance and foraging of Tibetan wild ass in Chang Tang Nature Reserve of Tibet.We also tested whether individuals scan the environment independently,tend to coordinate their scans,or tend to synchronize their vigilance.The results showed that individuals decreased the time spent on vigilance with increasing group size,while increased the time spent foraging.Group members scanned the environment at the same time more frequently and there was a positive correlation between group members'behaviors,indicating that Tibetan wild asses tend to synchronize their vigilance.     

N添加对西南亚高山红桦林根系分泌物及其介导的养分转化过程的影响

目前缺乏对根系分泌物通量以及相关生态后果对不同氮(N)沉降水平响应方向和幅度的深入理解,该研究以西南亚高山典型的红桦(Betula albosinensis)林为研究对象,通过野外原位N添加试验模拟不同氮沉降水平(对照组,0 kg·hm^-2·a(-1);低氮处理,25 kg·hm^-2·a(-1);高氮处理,50 kg·hm^-2·a(-1)),分析了红桦林根系分泌物C输入通量及其介导的根际土壤养分循环过程对不同N添加水平的差异化响应,试图揭示不同N添加处理对红桦根系分泌物C输入通量及其介导的土壤养分转化过程的影响。结果表明：(1)N添加显著抑制了红桦林根系分泌物C输入速率(其中低氮(N25)条件下单位根生物量根系分泌速率均值降低约14.87%)和年C输入通量(低氮条件下降低了约45.01%)(P<0.05),其高氮处理的抑制效应更强。(2)N添加显著抑制了红桦林N矿化速率及其相关的微生物胞外酶活性(P<0.05),并显著降低了其根际效应;N沉降显著抑制了根系分泌物C输入通量及其介导的土壤养分转化过程,并且这种抑...