线虫 Caenorhabditis elegans在甲基磺酸乙酯(EMS)中的毒性实验

基于C．elegans这种非寄生线虫,在生物遗传变异研究中的重要性与必要性,同时EMS(甲基磺酸乙酯)这种生态毒物,常用来作为生物实验中的诱变试剂,二者常常被同时选择作为生物基因遗传领域研究的对象。为定量了解EMS对线虫C．elegans的毒性作用,设计本实验,通过线虫的培养、线虫在EMS溶液中24h暴露、实验结果观察和分析这三个步骤,经过反复实验,摸索实验条件,进行浓度优化,从大量的数据汇总得到了其LC50的数值。为进一步对C．elegans的生物、生态、基因、遗传研究提供了良好的基础。也为通过线虫的生物理解来破解我们人类对自己物种的生物理解做前期的工作。     

Toxicity and neurophysiological effects of selected insecticides on the mole cricket, Scapteriscus vicinus (Orthoptera: Gryllotalpidae)

Mole crickets (Scapteriscus spp.) are severe subterranean pests of turfgrasses, commonly targeted with neurotoxic insecticides. Ideally insecticides used against mole crickets should induce quick knockdown or mortality to minimize damage caused by their tunneling. However, neurophysiological effects of insecticides on mole crickets are mostly unknown. The aims of this study were to investigate neurophysiological and toxic effects of several insecticides on tawny mole cricket (Scapteriscus vicinus Scudder) adults and nymphs, and potential synergy between pyrethroid and neonicotinoid insecticides. Bifenthrin, fipronil, and the combination of bifenthrin + imidacloprid provided the fastest median mortality when injected. The combination of bifenthrin + imidacloprid elicited faster toxicity than either active ingredient alone. Imidacloprid, bifenthrin, and bifenthrin + imidacloprid caused immediate knockdown, whereas fipronil immobilized mole crickets within 1-2 h. Acephate, bifenthrin, fipronil, imidacloprid, and bifenthrin + imidacloprid caused significant neuroexcitation. Bifenthrin + imidacloprid resulted in greater increases of spontaneous neural activity than the additive effects of imidacloprid and bifenthrin alone. Excitatory compounds acting at sodium and chloride channels (bifenthrin and fipronil) were the most toxic against S. vicinus. Combining a sodium channel toxin (bifenthrin) and a synaptic toxin (imidacloprid) led to greater than additive neurophysiological and toxic effects, which to our knowledge provides the first documented evidence of synergistic neurological “potentiation”.     

披针叶黄华抗杉木炭疽菌活性物质研究

预试验中发现披针叶黄华地上部分乙醇浸提物具有抗杉木炭疽菌活性 ,进一步用不同溶剂 ,在不同 p H值下萃取得到 4个组分 .生测表明披针叶黄华中生物碱部分对杉木炭疽菌的抑菌活性最强 .其生物碱对杉木炭疽菌分生孢子萌发较对菌丝生长的抑制活性强 ,对杉木炭疽菌的分生孢子和菌丝的 EC50分别为 1 36.0 μg/m L和 1 555.0 μg/m L     

小麦种子对二甲四氯敏感性的测定

以小麦为试材,测定了二甲四氯对小麦种子芽长、根长和鲜重的抑制作用。结果表明:二甲四氯对小麦种子芽长的72 hEC50为798.28 mg/kg;二甲四氯对小麦种子芽长、根长和鲜重的抑制作用之间存在极显著差异。     

食物颗粒和非食物颗粒对苏云金杆菌以色列亚种生物活性的影响

以埃及伊蚊幼虫为材料,比较了食物和非食物颗粒对苏云金杆菌以色列亚种致病能力的影响,结果表明：食物和非食物性颗粒皆能显著提高伊蚊幼虫对苏云金芽胞杆菌以及色列亚种商品制剂的抵抗力,颗粒物的这种作用与其营养功能无关。     

禽波氏杆菌对雏鸡和鸡胚毒力的测定

本文介绍了禽波氏杆菌对雏鸡和鸡胚毒力的测定。测定结果表明,禽波氏杆菌对2日龄公雏腹腔接种的 LD_(50)为1.352×10~4个菌,对12日龄鸡胚尿囊腔内接种的 MLD 低于196个菌。     

茶黄素提取物及茶黄素片的急性毒性

以茶黄素提取物及终端产品茶黄素片为原料,采用急性毒性试验方法,研究试验小鼠对茶黄素提取物和茶黄素片的急性毒理特性。结果表明,茶黄素提取物对雌性小鼠的急性经口LD50为2710.0 mg/kg体重,是成人日用量的(10~20 mg/kg)的136~271倍;对雄性小鼠LD50为3160.0 mg/kg体重,是成人日用量的(10~20 mg/kg)的158~316倍。茶黄素片对雌性小鼠的急性经口LD50为20000.0 mg/kg体重,是成人日用量的(40~50 mg/kg)的400~500倍;对雄性小鼠的急性经口LD50为14700.0 mg/kg体重,是成人日用量的(40~50 mg/kg)的294~368倍。茶黄素提取物和茶黄素片对雄性小鼠和雌性小鼠的急性经口LD50,均大于成人日用量的100倍,说明茶黄素提取物和茶黄素片的毒性较小,符合保健食品的急性毒性评价标准。     

茶树油粕中茶皂素的提取及其对果蔬采后致病菌的抑制作用

以从茶树油粕中提取茶皂素的得率为评价指标,研究提取溶剂、方法、时间、温度和料液比等因素对茶皂素得率的影响,并通过正交试验确定茶皂素最佳提取工艺条件,同时考察了所得茶皂素对几种果蔬采后致病菌的抑制作用。结果表明,茶树油粕中提取茶皂素的最佳工艺条件为:以75%乙醇作为提取溶剂,料液比1∶14(g/mL),85℃热回流提取2.5 h,茶皂素的得率达13.3%,经AB-8大孔吸附树脂纯化后,纯度达95.64%。所获茶皂素对胶胞炭疽菌(Colletotrichum gloeosporioides)、灰葡萄孢霉(Botrytis cinerea)和链格孢菌(Alternaria alternata)菌丝的生长均有显著的抑制作用,半最大效应浓度(EC50)值分别为203.62、165.87和550.61mg·L^-1,其中以对B. cinerea的抑制作用最强。     

Autumn growth and cold hardening of winter wheat under simulated climate change

Abstract

Plant responses to elevated CO₂ are governed by temperature, and at low temperatures the beneficial effects of CO₂ may be lost. To document the responses of winter cereals grown under cold conditions at northern latitudes, autumn growth of winter wheat exposed to ambient and elevated levels of temperature (+2.5°C), CO₂ (+150 µmol mol^?1), and shade (?30%) was studied in open-top chambers under low light and at low temperatures. Throughout the experiment, temperature dominated plant responses, while the effects of CO₂ were marginal, except for a positive effect on root biomass. Increased temperature resulted in increased leaf area, total biomass, total root biomass, total stem biomass, and number of tillers, but also a lower content of total sugars and a weaker tolerance to frost. The loss of frost tolerance was related to the larger size of plants grown at elevated temperature. The 30% light reduction under shading did not affect the growth, sugar content, or frost tolerance of winter wheat. At the low temperatures found at high latitudes during autumn, the atmospheric CO₂ increase is unlikely to enhance autumn growth of winter wheat to any significant extent, while a temperature increase may have important and major effects on its development and growth.     

3种半数致死浓度计算方法之比较

通过对寇氏法、概率单位法及线性回归法等3种半数致死浓度(50％ lethal concentration,LC50)计算方法的阐述,比较了其基本公式与操作方法等.结果表明不同时间的半数致死浓度均依线性回归法、寇氏法、概率单位法的顺序逐步升高,但差异性不显著(P＞0.05).在操作上,概率单位法和线性回归较寇氏法更容易掌握.