饲料蛋白水平对血鹦鹉幼鱼生长、体组成和肠道蛋白消化酶活性的影响

为考察饲料蛋白水平对血鹦鹉CichZasoma sp.幼鱼生长、体组成和肠道蛋白消化酶活性的影响,以鱼粉和豆粕为主要蛋白源配制了蛋白质含量分别为37%、40%、43%、46%和49%五种饲料,饲养平均体重为0.66 g的血鹦鹉6周.结果表明:血鹦鹉幼鱼摄食上述5种饲料后,增重率分别为868.51%、935.95%、1018.28%、925.16%和873.86%,饲料系数分别为1.55、1.48、1.41、1.47和1.56,摄食饲料蛋白质水平43%饲料的血鹦鹉幼鱼具有最佳生长性能.对全鱼体组成成分的分析表明:血鹦鹉幼鱼鱼体粗蛋白和粗灰分的含量随着饲料中蛋白含量的增加而增加,而体脂肪含量则呈下降趋势;在肠道蛋白酶及肝脏GOT、GPT活性方面:随着饲料中蛋白含量的增加,血鹦鹉幼鱼前肠组织和内容物蛋亡J酶活性及肝脏GOT、GPT活性也增加,当蛋白含量达到43%时均达到最大值.研究表明血鹦鹉幼鱼对饲料蛋白的最佳需求量为43%.     

GSH inhibits trypsinization of the C-terminal half of human MRP1

MRP1 is a 190-kDa membrane glycoprotein that confers multidrug resistance to tumor cells. The accumulated evidence has proved that GSH interacts with MRP1 and stimulates drug transport. However, the mechanism of GSH-dependent drug transport by MRP1 remains unclear. In this study, we used limited tryptic digestion of MRP1 in isolated membrane vesicles, in the presence and absence of GSH, to investigate the influence of GSH on MRP1 conformation. We found that GSH inhibited the generation of an approximately 35-kDa C-terminal tryptic fragment (including a C-terminal His tag) termed C2 from MRP1. This effect of GSH was not because of direct inhibition of trypsin activity, and agosterol A enhanced the inhibitory effect of GSH. The main cleavage site in MRP1 for the generation of the C2 fragment by trypsin resided between TMD2 and NBD2 of MRP1. Limited tryptic digestion of membrane vesicles expressing various truncated and co-expressed MRP1 fragments in the presence and absence of GSH revealed that GSH inhibited the production of the C2 fragment only in the presence of the L(0) region of MRP1. Thus the L(0) region is required for the inhibition of trypsinization of the C-terminal half of MRP1 by GSH. These findings, together with previous reports, suggest that GSH induces a conformational change at a site within the MRP1 that is indispensable for the interaction of MRP1 with its substrates.     

苍术（Atractybeslancea（Thunb．）DC．）种内遗传多样性分析

分析了苍术（Ａｔｒａｃｔｙｌｏｄｅｓｌａｎｄｅａ（Ｔｈｕｎｂ．）ＤＣ．）５种等位酶（ＭＤＨ,ＧＤＨ,ＰＰＯ,ＳＯＤ,ＰＥＲ）１２个位点上２５个等位基因的分化特征。结果表明：群体内多态位点比例平均为０．６１,每个位点的平均杂合率为０．２６,每个位点发现的平均等位基因数为１．７８。苍术种内基因多样性的８６％产生在群体内,群体间分化的明显效果为１４％。所有配对组合,群体间的平均遗传距离是０．１１,遗传同一性是０．９０。说明苍术种内变异很大。同时探讨茅苍术的分类位置,认为茅苍术不是苍术和白术的杂交种。     

河内蚁蛛雌性记述(蜘蛛目,跳蛛科)

首次发现并报道了采自云南的跳蛛科蚁蛛属河内蚁蛛Myrmarachne hanoii,Zabka,1985的雌性个体。为我国新纪录种。文中详细描述了本种雌性个体的特征及与其近似种的比较,同时附有特征图。研究标本保存于湖南中医药大学。     

荨麻科楼梯草属植物瘦果的补充描述

楼梯草属植物的瘦果具有较高的形态多样性,可作为种类鉴定的重要依据.然而,中国超过半数楼梯草属植物缺少瘦果形态信息.该研究通过野外考察、标本查阅以及光镜和扫描电镜的观察,对七种楼梯草属植物的瘦果进行了补充描述,并提供了墨线图和照片.该研究结果对该属的进一步分类修订提供了有价值的信息.     

一种耐热几丁质酶的产生及其稳定性研究

疏绵状嗜热丝孢菌(Thermomyces lanuginosus)SY2 在以胶状几丁质为唯一碳源的诱导培养基中产生了胞外几丁质酶.该酶在50℃保温1 h,酶活稳定;65℃时半衰期为25 min;酶液在室温下保存到12周,残余酶活性为45%左右.该酶有较宽的pH范围,3.0～9.0之间保持稳定,pH值为2.5时,仍具有70%的剩余酶活性.Ca2 对几丁质酶的活性有显著的激活作用;高浓度变性剂对酶有抑制作用.结果表明该酶是一种热稳定性高且耐酸碱的新型几丁质酶,能在酸性和高温环境中发挥作用,这些特性赋予了T.lanuginosus几丁质酶在几丁质的生物转化及其它生物技术中极大的应用优势.     

美洲斑潜蝇成虫的卵巢结构观察及营养影响卵子发生的试验

卵育型(Synovigenic)植食性昆虫的雌成虫需要取食寄主植物组织或非寄主食物(如花蜜、花粉等)以延长寿命和促进产卵。为了明确寄主食物和非寄主食物对美洲斑潜蝇Liriomyza sativae卵子发生的功能差异,本实验在明确美洲斑潜蝇成虫卵巢发育动态和结构的基础上,比较了清水(饥饿,对照)、菜豆叶片、20%葡萄糖溶液、菜豆叶片+20%葡萄糖溶液四种处理下的雌成虫卵子发生动态。结果显示:美洲斑潜蝇为强卵育型昆虫,初羽化成虫体内无卵子;两侧卵巢管数之和为11-18根,大多数情况下,左右两侧卵巢管数目不等。成虫在饥饿条件下,几乎不能形成成熟卵子;继续取食寄主叶片、20%葡萄糖溶液和寄主叶片+20%葡萄糖溶液,均可显著促进卵子发生和卵成熟,但补充葡萄糖溶液起到极显著促进作用;成虫不具备卵子重吸收功能。本文重点从卵育型角度,对美洲斑潜蝇取食寄主食物和非寄主食物的营养功能进行了讨论。研究结果为美洲斑潜蝇以及该类植食性害虫的室内饲养和田间生态调控提供了依据。     

刺槐叶瘿蚊在中国的危险性评估

采用CLIMEX模型预测分析了刺槐叶瘿蚊Obolodiplosis robiniae(Haldemann)在中国的潜在地理分布,并参照我国有害生物危险性定量分析方法,对刺槐叶瘿蚊在中国的危险性作出综合评价.结果表明:刺槐叶瘿蚊在中国潜在的分布区范围是98 30°～132.03°E,24.23°～47.41°N.最宜适生区(EI ≥ 15)包括华北、华中、华南及云南大部分地区;适生区(5 ≤ EI＜15):包括辽宁和河北中南部,山西及陕西南部,四川、甘肃东南部分地区;半适生区(0 ＜ EI ＜ 5):包括黑龙江、吉林、四川大部分地区及西藏、甘肃、宁夏部分地区;其余各地的EI值均小于等于0,属于非适生区.预测其在中国的风险值为2.26,根据国际上风险值分级标准,属于高度危险生物.据此提出了针对性的风险管理措施.     

Development and validation of a liquid chromatography-tandem mass spectrometry method for the determination of xanthinol in human plasma and its application in a bioequivalence study of xanthinol nicotinate tablets

A sensitive, rapid liquid chromatographic-electrospray ionization mass spectrometric method for the determination of xanthinol in human plasma was developed and validated. Xanthinol nicotinate in plasma (0.5mL) was pretreated with 20% trichloroacetic acid for protein precipitation. The samples were separated using a Lichrospher silica (5mum, 250mmx4.6mm i.d.). A mobile phase of methanol-water containing 0.1% formic acid (50: 50, v/v) was used isocratically eluting at a flow rate of 1mL/min. Xanthinol and its internal standard (IS), acyclovir, were measured by electrospray ion source in positive selected reaction monitoring mode. The method demonstrated that good linearity ranged from 10.27 to 1642.8ng/mL with r=0.9956. The limit of quantification for xanthinol in plasma was 10.27ng/mL with good accuracy and precision. The mean plasma extraction recovery of xanthinol was in the range of 90.9-100.2%. The intra- and inter-batch variability values were less than 4.8% and 7.9% (relative standard deviation, R.S.D.), respectively. The established method has been successfully applied to a bioequivalence study of two xanthinol nicotinate tablets for 20 healthy volunteers.     

植物凯民带的研究进展

凯氏带是植物内皮层细胞径向壁和横向壁的带状增厚部分,近年来对其细微结构、化学成分、生理功能以及在植物体的存在部位等方面的研究工作已成为国内、外的研究热点。本文就凯氏带上述诸方面的研究进展,作一详尽的论述,同时还着重对凯氏带研究的新方法和新技术作了评述。最后对凯氏带的进一步研究工作提供新的启示。