蓖麻粗毒的分离、提取及野外灭鼠初步试验

以小鼠活性实验摸索了分离、提取蓖麻粗毒的提取溶剂和条件,确定其主要药效成分为蓖麻毒素,对小鼠腹腔注射的LD50为7.971μg/kg,以1%浓度(以饵料重量计)粗毒野外实验对高原鼠兔的校正灭效为85%以上。     

蓖麻提取物对鼠抗生育作用的实验研究

利用蓖麻提取物对昆明种小鼠进行了短期与长期的抗生育实验,研究发现蓖麻提取物（蓖麻油和蓖麻蛋白）对小鼠有明显的抗生育作用。蓖麻蚩白及其与蓖麻油的混合物在抗早孕方面的效果均可达到100％,蓖麻油抗着床的效果也可达到100％。蓖麻油长期抗鼠生育效果明显,在210d（正常小鼠的妊娠期是21～23d）内有效降低小鼠生育代数与产仔数,生育抑制率达80％以上。蓖麻提取物对离体小鼠子宫的影响也非常显著,通过增强小鼠子宫内部收缩有效减少着床机率。在中止妊娠的实验中发现,服用了蓖麻蛋白及其与蓖麻油的混合物的小鼠子宫内没有着床位点。     

虎纹捕鸟蛛毒的生物学活性鉴定

本文报道了采集广西产虎纹捕鸟蛛（Selenocosmia huwena)毒液的方法,并对粗毒进行了部分生物学活性的测定,该粗毒对小鼠和蜚蠊的LD50分钟为1．16mg/kg和300ug/g,该粗毒具有透明质酸酶,碱性磷酸酶,蛋白水解酶和脱氧核糖核酸酶活性,未测到磷脂酶A和胆碱脂酶性,通过电生理实验发现该粗毒含有阻断蟾蜍神经肌肉接头传递的毒素,并观察到当小鼠接受腹腔注射致死剂量（5mg/kg)粗毒后便迅速出现呼吸麻痹。     

蓖麻碱的提取、纯化、改性及其杀虫活性研究

蓖麻饼中含有生物碱等毒性物质,主要杀虫活性物质为蓖麻毒蛋白和蓖麻碱,蓖麻碱是蓖麻中的主要毒素之一,具有一定的生物活性。本文研究了蓖麻碱的提取、纯化,以及将所得蓖麻碱再进一步进行改性,探讨改性方法。采用红外光谱方法对蓖麻碱改性前后变化进行对比;并对提取、纯化以及改性过程中的各个环节的物质进行杀虫实验,对实验结果进行观察。结果表明,蓖麻碱的主要杀虫活性基团为氰基。     

间斑寇蛛粗毒的生物学特性

近几十年来,间斑寇蛛(Latrodectus tredecimguttatus)已引起相关研究工作者的广泛关注,因为阐明其毒液中的特异性蛋白质和多肽活性成分对蜘蛛咬伤治疗具有重要的意义,且其粗毒液中的生物学活性成分在神经生物学和药物研究方面也有着潜在的应用前景。但直到现在,尽管已有不少研究报道了包括α-latrotoxin在内的几种间斑寇蛛毒性蛋白质的生物学性质和结构,但有关毒液生物学特性的系统研究的报道还很少。本研究采用解剖分离毒囊的方法从产于我国新疆的间斑寇蛛提取粗毒,并对其理化和生物学性质进行了系统的分析。定量测定结果表明,粗毒的蛋白质含量为36.99%,对小鼠和蜚蠊的LD50分别为0.39mg/kg和2.32μg/g体重。小鼠经腹腔注射粗毒后,出现呆滞、共济失调、排汗、痉挛、食欲减退、呼吸短促、睁眼困难等中毒症状,而注射生理盐水的对照小鼠活动正常。粗毒具有透明质酸酶、碱性磷酸酶、酸性磷酸酶、脱氧核糖核酸酶、乙酰胆碱酯酶、蛋白水解酶等多种水解酶的活性。10μg/ml该粗毒可以在31min±3.05min内完全抑制电刺激引起的大鼠输精管的收缩反应。6μg/ml粗毒可在25min±2.2min内完全阻断小鼠膈神经-膈肌标本的神经肌肉接头传递。膜片钳电生理实验显示,粗毒(1g/L)对蜚蠊背侧不成对中间(Dorsal unpaired median,DUM)神经元的快瞬时钾电流、钠电流、高电压激活的钙电流和大鼠背根神经节(Dorsal root ganglion,DRG)细胞延迟整流钾电流、TTX-S型钠电流、高电压激活的钙电流均无明显作用。     

用琼脂糖亲和层析一步纯化蓖麻毒蛋白

本文报道了一种单用琼脂糖(Sepharose4B)来纯化蓖麻毒蛋白的快速简便的方法。我们发现在pH5的条件下,蓖麻毒蛋白和与其密切相关的蓖麻凝集素对琼脂糖的结合能力有很大的差别。在有0.2mol/LD-半乳糖存在下可将蓖麻毒蛋白从Sepharose上洗下,同样条件下蓖麻凝集素仍牢固地结合在柱上。从而经一步柱层析便可得到电泳纯的蓖麻毒蛋白。此法不需另行合成亲和胶,适合于蓖麻毒蛋白的大规模纯化。     

蓖麻毒蛋白A链基因RNAi转化研究

通过基因沉默技术调控蓖麻毒蛋白A链基因的表达,以期获得低毒蓖麻新材料.利用基因克隆技术获得蓖麻毒蛋白A链基因762 bp片段,命名为RTA基因.进一步利用该基因构建了植物RNAi表达载体pBI-RTA-S-AS,通过农杆菌介导法转化蓖麻子叶节,用卡那抗性筛选转化再生植株,PCR进一步鉴定转基因植株.结果表明:克隆得到目的基因长762 bp,与预期结果一致;卡那抗性筛选和PCR鉴定结果显示,获得了3株转基因阳性植株.     

杠柳萃取物对小菜蛾幼虫的毒杀活性研究

以杠柳Periploca sepium Bunge的根为材料进行甲醇超声波提取,粗提物以水／氯仿（1：1,v／v）萃取获得杠柳根氯仿萃取物。测定了萃取物对小菜蛾Plutella xyllostellaL．3龄幼虫的胃毒和触杀活性。实验结果显示,在50μg／头剂量处理下24h和48h后,氯仿萃取物对小菜蛾3龄幼虫的胃毒死亡率分别为82．22％和92．59％,显著高于触杀死亡率58．89％和68．15％。这一结果表明,杠柳根中含有对小菜蛾幼虫具有较强胃毒作用的活性成分。     

海洋放线菌124092细胞毒活性和化学成分研究

采用MTT法对海洋放线菌124092正己烷提取物进行细胞毒活性筛选,结果显示对小鼠B16黑色素瘤细胞有一定的生长抑制活性。用硅胶真空柱层析法将正己烷提取物粗分为6个组分（Fr1～Fr6）,细胞毒活性追踪显示Fr6组分为活性部分。为确定其中的活性成分,运用GC／MS对脯组分的化学成分进行了分析,结果显示其主要成分为：棕榈酸（Palmitic acid,11．76％）、油酸（Oleic acid,12．16％）、亚油酸（Linoleic acid．14．77％）和乳杆（菌）酸（Lactobacillic acid,61．31％）。据文献报道棕榈酸、油酸、亚油酸均对小鼠腹水瘤细胞具有细胞毒活性,亚油酸还对人肺腺癌细胞具有抑制作用。     

包有蓖麻毒蛋白的脂质体的制备,性质及毒性研究

以半乳糖神经酰胺（ｇａｌａｃｔｏｓｙｌｃｅｒａｍｉｄｅ,ＧＣ）为材料,采用冷冻干燥脱水再水化法（ＤＲＶ法）制成包裹有蓖麻毒蛋白的半乳糖神经酰胺脂质体（ｒｉｃｉｎＧＣＬｓ）并对其性质及体外细胞毒性和动物毒性做了研究,实验结果表明,ｒｉｃｉｎ－ＧＣＬｓ的最大包封率可达７４．１％,粒度分布主要在０．５～０．８μｍ之间,符合静脉注射液的标准,脂质体冻干粉在４℃储存近半年,粒度分布几乎没有变化,体外细胞毒性     

亚稀褶黑菇对小白鼠肝肾超微结构的影响

对小白鼠用亚稀褶黑菇提取液进行毒性试验．测定了亚稀褶黑菇的半致死剂量LD50值;应用透射电镜观察了小白鼠亚稀褶黑菇中毒后的病理变化,结果表明．亚稀褶黑菇的LD50值为2852．1mg／kg,电镜检查发现。亚稀褶黑菇毒素主要损害肾脏,引起肾细胞核核膜肿胀．线粒体肿胀,溶酶体增多,肾细胞坏死．     

士的宁杀灭高原鼢鼠的试验研究

士的宁(strychnine)是从番木鳖(Shrychox nuxvomica)种子提得的一种生物碱。作为兴奋剂用于医疗方面和作为生化试剂使用,但作为杀鼠剂用来防治害鼠,国内尚未见有报道。在国外,士的宁被用于防治危害森林草地、作物地内的地下鼠和其它有害哺乳动物(Marsh,1978;Barnes,1980;Crouch,1980;Anthony,1984)。作者于1983-1984年期间针对草原主要害鼠之一--高原鼢鼠(Myospalax baileyi)进行了灭杀试验研究。     

Differential susceptibility of species of slugs to metaldehyde/bran and to methiocarb baits

Summary Laboratory experiments were designed to study differential susceptibility of nine species of slugs to metaldehyde/bran and to methiocarb baits. Differential susceptibility was found between some of the species for each type of bait, both immediately after baiting and also after a 48 h recovery period. Thus neither type of bait is suitable for use in ecological investigations. This conclusion was supported by evidence that interspecific behavioural interactions occurred when metaldehyde, but not methiocarb, baits were used.At the same time the relative efficiency of the two types of baits as molluscicides was estimated. Methiocarb was shown to be a better molluscicide because, not only did it initially poison more slugs than did metaldehyde, but also a number of the slugs initially poisoned by metaldehyde recovered during the following 48 h period, whereas this did not happen with methiocarb. The similarity between these results and those obtained from field experiments by other workers is discussed.     

Distribution of receptor sites on large glycoprotein molecules by electron microscopy. Application to epiglycanin.

Electron microscopy was used to map the loci of immunochemically active sites on individual glycoprotein molecules. The positions of specific galactose residues and asparagine-linked carbohydrate chains containing specific mannose residues in epiglycanin, a glycoprotein of extended conformation from the surface of TA3 mouse mammary tumour cells, were observed in complexes with Ricinus communis toxin and concanavalin A respectively. The maximum number of Ricinus communis toxin molecules attached to a single epiglycanin molecule was 23, and the average number was 16. Only one concanavalin A molecule was observed attached to any epiglycanin molecule, and this at one end of the molecule, suggesting the presence of only one receptor for this lectin. By means of this new approach for mapping specific residues, evidence has been obtained that suggests microheterogeneity in epiglycanin with respect to the locations of carbohydrate chains containing receptors for Ricinus communis toxin.     

Survival of PIT-tagged lesser short-tailed bats (

Introduced mammalian predators are a major threat to New?Zealand?s wildlife, including bats. Controlling these predators using traps and poison baits can reduce their impact on bat populations. However, lesser short-tailed bats (Mystacina tuberculata) are potentially susceptible to toxins used for pest control in New?Zealand forests because of their broad diet and habit of feeding on the ground. Therefore, the risk of secondary poisoning should always be assessed before new toxins are used in areas inhabited by lesser short-tailed bats. We measured survivorship of a sample of lesser short-tailed bats monitored before, during and after deployment of the first-generation anticoagulant toxin pindone in the Eglinton Valley, Fiordland, during late winter and summer 2009?2010. Pindone-laced cereal baits were deployed in bait stations from September to late December 2009 in an effort to control rats (Rattus spp.). Communal roosts of the one lesser short-tailed bat colony in the valley are located entirely within or immediately adjacent to the area poisoned. Minimum number alive was determined for the sampled bat population after monitoring the occupancy of colonial roosts by individually PIT-tagged bats through the study period. Survivorship of bats was high throughout the monitoring period, with 319 of 322 bats (99%) recorded in the pre-monitoring period (August) known to be alive in October 2009 and 312 of 322 bats (97%) known to still be alive in January 2010. We conclude that lesser short-tailed bats did not consume pindone baits and that their survival was probably enhanced by rat control in the study area.     

Evidence for the involvement of nematocidal toxins of <Emphasis Type="Italic">Purpureocillium lilacinum</Emphasis> 6029 cultured on Karanja deoiled cake liquid medium

In present study, in vitro nematocidal bioassays, FT-IR and HPLC analysis were employed to demonstrate the involvement of toxins of Purpureocillium lilacinum in killing root-knot nematodes (Meloidogyne incognita). During growth study, maximum mycelial biomass (10.52 g/l) in de-oiled Karanja cake medium was achieved on 8th day while complete mortality of nematodes was obtained by 6th day filtrate (FKSM). Maximum production of crude nematocidal toxin was recorded on 7th day suggesting that the toxin production was paralleled with growth of the fungus. The median lethal concentration (LC₅₀) determined for the crude toxin from 6th day to 10th day ranged from 89.41 to 43.21 ppm. The median lethal time (LT₅₀) for the crude toxin of FKSM was found to be 1.46 h. This is the first report of implementing a comparative infra-red spectroscopy coupled with HPLC analysis to predict the presence of nematocidal toxin in the fungal filtrate cultured on Karanja deoiled cake liquid medium.     

Ultrastructural changes in β-cells of pancreatic islets in α-amanitin-poisoned Mice

In mice poisoned by alpha-amanitin nuclear changes typical of this toxin were observed in beta-cells of pancreatic islets. The lesions became progressively more severe and at 48 h after toxin injection some cells were necrotic. The damage to these cells could have implications in the changes in glycogen metabolism which occur after alpha-aminitin poisoning.     

Poisoning mammalian pests can have unintended consequences for future control: Two case studies

Vertebrate pest control operations using toxic baits can have unintended consequences for nontarget species. some of which may themselves be pests. Learned avoidance behaviour (termed 'aversion') can be induced by sublethal dosing, which can arise when species with high and low susceptibilities to a toxin co- exist in the same area. In such cases the less-susceptible species (e.g., possums Trichosurus vulpecula) may be sublethally poisoned by control work targeting the more- susceptible species (e.g., rabbits Oryctolagus cuniculus). A case study of rabbit control on North Canterbury farmland is presented to demonstrate this effect. When control is being rePeated at frequent intervals, it is prudent to vary the control methods used. Nevertheless, aversion induced by the use of one toxic bait (e.g., cyanide paste) can in some situations 'generalise' so that the efficacy of control using other toxins (e.g., 1080 and cholecalciferol in cereal baits) is also compromised. A case study of initial and follow-up possum control in four discrete areas of Canterbury forest provides an example of this problem. The implications of these findings for future pest management in New Zealand are discussed.     

Successful removal of German yellowjackets (Hymenoptera: Vespidae) by toxic baiting

Vespula germanica (F.) is a social vespid that has invaded many parts of the world, including Argentina. This wasp usually becomes a pest, affecting several economic activities. It also may impact the host community through predation or competition. The purpose of our study was to field test toxic baiting for reduction of wasp abundance. Wasps were poisoned with 0.1% fipronil mixed with raw minced beef in two beech forest sites on 20 February 2000 in northwestern Patagonia. All nests (46) within the two 6-ha sites with poisoned bait stations were killed, whereas Malaise traps in those sites captured 81.1% fewer wasps at the end of the season than traps in the two control sites. The average reduction of forager wasps on nontoxic baits was 87%. Fipronil was very effective in controlling wasp numbers, although there are limitations to the method, especially concerning conservation purposes. Toxic baiting can be useful in controlling wasp numbers in honey bee hive yards, farms, and parks.     

Production of a novel and cold-active killer toxin by Mrakia frigida 2E00797 isolated from sea sediment in Antarctica

The psychrotolerant yeast Mrakia frigida 2E00797 isolated from sea sediment in Antarctica was found to be able to produce killer toxin against the pathogenic yeast (Metschnikowia bicuspidata WCY) in crab. When the psychrotolerant yeast was grown in the medium with pH 4.5 and 3.0% (wt/vol) NaCl and at 15°C, it could produce the highest amount of killer toxin against the pathogenic yeast M. bicuspidata WCY. The crude killer toxin activity against the pathogenic yeast M. bicuspidata WCY was the highest when it grew at 15°C in the assay medium with 3.0% (wt/vol) NaCl and pH 4.5. At temperatures higher than 25°C, the killing activity produced by M. frigida 2E00797 was completely lost and after the crude killer toxin was pre-incubated at temperatures higher than 40°C for 4 h, the killing activity was also completely lost. The killer toxin produced by M. frigida 2E00797 could kill only M. bicuspidata WCY, Candida tropicalis and Candida albicans among all the fungal species and bacterial species tested in this study.