寄主植物对烟蚜药剂敏感性及相关酶活性的影响

以甘蓝、烟草和桃树上的饲养的烟蚜Myzus persicae（Sulzer）种群为研究材料,分别测试了其对吡虫啉、丁硫克百威和氰戊菊酯这3种杀虫剂的敏感性。结果表明,桃树上的烟蚜种群敏感性最高,其次为烟草种群,甘蓝种群最低。测试了在3种不同寄主上饲养的烟蚜种群的羧酸酯酶、乙酰胆碱酯酶和谷光甘肽-s-转移酶的比活力,这3种酶均表现为甘蓝种群最高,其次为烟草种群,桃树种群最低。     

几种药剂对烟蚜毒力的温度效应

在15℃、20℃、25℃、30℃及35℃条件下分别测定了吡虫啉、丁硫克百威和氰戊菊酯对烟蚜毒力的温度效应。结果显示，吡虫啉和丁硫克百威对烟蚜的毒力呈正温度效应，但随着温度上升，烟蚜对吡虫啉的敏感性变化比丁硫克百威大。毗虫啉毒力在35℃时为15℃时的7．12倍；而丁硫克百威为2．88倍。氰戊菊酯对烟蚜的毒力呈负温度效应，在35℃时的毒力约为15℃时的1／5。鉴于这些药剂的毒力受温度影响的规律，建议在气温较低时选用氰戊菊酯等负温度效应的农药，在气温较高时则选用吡虫啉等正温度效应的农药，以充分发挥农药的性能，减少农药使用量、降低防治成本。     

几种药剂对烟蚜毒力的温度效应

在15℃、20℃、25℃、30℃及35℃条件下分别测定了吡虫啉、丁硫克百威和氰戊菊酯对烟蚜毒力的温度效应.结果显示,吡虫啉和丁硫克百威对烟蚜的毒力呈正温度效应,但随着温度上升,烟蚜对吡虫啉的敏感性变化比丁硫克百威大.吡虫啉毒力在35℃时为15℃时的7.12倍;而丁硫克百威为2.88倍.氰戊菊酯对烟蚜的毒力呈负温度效应,在35℃时的毒力约为15℃时的1/5.鉴于这些药剂的毒力受温度影响的规律,建议在气温较低时选用氰戊菊酯等负温度效应的农药,在气温较高时则选用吡虫啉等正温度效应的农药,以充分发挥农药的性能,减少农药使用量、降低防治成本.     

甜菜夜蛾不同龄期幼虫对药剂的敏感性及其与酶活力的关系

【目的】明确甜菜夜蛾Spodoptera exigua(Hübner)不同龄期幼虫对甲氨基阿维菌素苯甲酸盐和毒死蜱的敏感性及其与羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶活性的相关性。【方法】采用室内生物测定方法检测甜菜夜蛾不同龄期幼虫对药剂的敏感性,并检测了不同龄期幼虫体内羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶的活力。【结果】在所测定的5个龄期中,随龄期增加,敏感性逐渐降低,其中1~5龄幼虫对甲氨基阿维菌素苯甲酸盐的LC50分别为0.1010、0.3561、0.7568、1.4325和8.4390 mg/L,对毒死蜱的LC50分别为27.4632、46.8495、87.5222、129.3217和1 356.6770 mg/L。单头幼虫的羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶活力随虫龄的增加而提高,与龄期间对药剂的敏感性呈负相关(由于外源化合物摄入量减少,5龄单头幼虫的多功能氧化酶活力略有降低)。【结论】甜菜夜蛾不同龄期幼虫对药剂的敏感性存在非常明显的差异,在田间防治中,应选择对杀虫剂敏感性较高的低龄幼虫作为最佳防治时期。     

两种体色生物型桃蚜对杀虫剂敏感性差异及其与酶活力的关系

为了明确不同体色生物型桃蚜Myzus persicae (Suizer)对药剂的敏感性差异,本文采用室内生物测定和酶活力测定法检测不同体色生物型桃蚜对杀虫剂的敏感性以及与3种解毒酶和1种靶标酶活力关系。结果表明,红色生物型的敏感性明显低于绿色生物型,其中对吡虫啉的敏感性差异最大,LC50分别为6796648和284597 mg/L,红色为绿色生物型2388倍;其次为毒死蜱,LC50分别为12295798和1936816 mg/L,红色为绿色生物型635倍;两种生物型桃蚜对阿维菌素敏感性差异最小,红、绿色生物型的LC50分别为311678 和290966 mg/L,红色为绿色生物型107倍。红色生物型体内3种解毒酶（羧酸酯酶、谷胱甘肽-S-转移酶和多功能氧化酶P450）的比活力均高于绿色生物型,红色型羧酸酯酶比活力为绿色型的31倍,谷胱甘肽-S-转移酶为41倍,多功能氧化酶P450为15倍,两种体色生物型3种解毒酶的活力差异均达显著水平。两种体色生物型体内乙酰胆碱酯酶比活力没有差异,说明乙酰胆碱酯酶比活力与敏感性关系不大。     

我国棉花主产区棉蚜对吡虫啉的抗性监测及抗性机理

【目的】由于生长周期短、繁殖率高,棉蚜Aphis gossypii容易对杀虫剂产生抗药性。本研究旨在明确我国棉花主产区棉蚜对吡虫啉的抗性水平及抗性机理。【方法】采用浸叶法测定了北京海淀,河北廊坊和邯郸,山东德州,河南许昌,以及新疆奎屯和阿克苏地区棉蚜对吡虫啉的抗性水平;测定了不同种群棉蚜3种解毒酶（多功能氧化酶、羧酸酯酶、谷胱甘肽S-转移酶）及乙酰胆碱酯酶的活性;并对靶标基因烟碱型乙酰胆碱受体（nAChR）β1亚基基因进行了突变检测。【结果】北京海淀、河南许昌和河北邯郸的棉蚜对吡虫啉敏感;河北廊坊、新疆阿克苏、山东德州及新疆奎屯地区的棉蚜对吡虫啉的抗性倍数(resistance ratio, RR)分别为22.6, 26.3,53.5和61.1倍,为中等水平抗性。酶活力对比研究发现,阿克苏和奎屯地区的棉蚜多功能氧化酶的比活力分别是敏感种群(北京种群)的1.7和1.8倍,羧酸酯酶的比活力分别是敏感种群的1.6和1.7倍,谷胱甘肽S-转移酶的比活力均是敏感种群的1.5倍,但是乙酰胆碱酯酶比活力在棉蚜种群间差异不显著。靶标基因突变检测表明,河北廊坊、新疆阿克苏、山东德州及新疆奎屯棉蚜种群nAChR β1亚基均存在与吡虫啉抗性相关的精氨酸到苏氨酸（R81T）突变。【结论】结果提示,多功能氧化酶、羧酸酯酶和谷胱甘肽S-转移酶活力升高以及nAChR β1亚基R81T突变与棉蚜对吡虫啉的抗性形成相关。     

马尾松毛虫蛋白质、核酸酶和羧酸酯酶与耐药性的关系

马尾松毛虫(Dendrolimus punctatus Walker)幼虫蛋白质含量、羧酸酯酶和多酚氧化酶活力与虫龄大小成正相关;氰戊菊酯处理后,兴奋期的蛋白质含量和羧酸酯酶活力上升,到抑制期均降低到正常虫体的水平,而多酚氧化酶的变动不大。正常虫体中脱氧核糖核酸酶(DNase)和核糖核酸酶(RNase)的活力存在差异:DNase从3—5龄幼虫随虫体增大而上升,到6龄时明显降低;RNase与虫龄大小成负相关;氰戊菊酯处理后,DNase便开始下降并低于正常虫体的水平,而RNase在兴奋期上升,到抑制期下降亦低于正常虫体水平。结果说明,除多酚氧化酶外,蛋白质、核酸酶和羧酸酯酶均与耐药性存在一定的相关性,研制酶的抑制剂具有实用意义。根据毒力测定结果,马尾松毛虫幼虫随虫龄增大而耐药力增加,氰戊菊醋对5龄幼虫是3龄的2.8倍,6龄是4龄的2.3倍。因此,掌握在4龄前进行药物防治是合理的。     

家蝇中乙酰胆碱酯酶、羧酸酯酶和多功能氧化酶活性与抗药性的关系

本文对几种抗药性和敏感性家蝇品系的乙酰胆碱酯酶(AChE)、羧酸酯酶及多功能氧化酶(MFO)进行了测定.结果表明:①抗药性品系和敏感性品系的AChE活力差异不大, 有机磷抗性品系的AChE对对氧磷的不敏感性比敏感性家蝇明显增大.②某些抗药性家蝇的羧酸酯酶活力比敏感性家蝇大.③抗药性家蝇的MFO活力(O-脱甲基和环氧化)比敏感性家蝇均有不同程度的增高.④二氯苯醚菊酯抗性家蝇对有机磷有负交互抗性.     

马尾松毛虫蛋白质、核酸酶和羧酸酯酶与耐药性的关系

马尾松毛虫(Dendrolimus Punctatus Walder)幼虫蛋白质含量,羧酸酮酶和多酚氧化酶活力与虫龄大小成正相关;氰戊菊酯处理后,兴奋期的蛋白质含量和羧酸酯酶活力上升,到抑制期均降低到正常虫体的水平,而多酚氧化酶的变动不大。正常虫体中脱氧核糖核酸酶(Dnase)和核糖核酸酶(Rnase)的活力存在差异：Dnase从3-5龄幼虫随虫体增大而上升,到6龄时明显降低;Rnase与虫龄大小成负相关;氰戊菊酯处理后,Dnase便开始下降并低于正常虫体的水平,而Rnase在兴奋期上升,到抑制期下降亦低于正常虫体水平。结果说明,除多酚氧化酶外,蛋白质、核酸酶和羧酸酯酶均与耐药性存在一定的相关性,研制酶的抑制剂具有实用意义。根据毒力测定结果,马尾松毛虫幼虫随虫龄增大而耐药力增加,氰戊菊酯对5龄幼虫是3龄的2.8倍,6龄是4龄的2.3倍。因此,掌握在4龄前进行药物防治是合理的。     

棉铃虫抗药性的生理生化机制研究

本文报道了棉铃虫Helicoverpa armigera田间抗性种群对杀虫剂抗药性的生理生化机制。抗性种群(HJ-R)5龄幼虫羧酸酯酶、谷胱甘肽转移酶、多功能氧化酶活力均明显高于相对敏感种群(HD-S)。两种群乙酰胆碱酯酶对杀虫剂敏感性没有显著差异。HJ-R种群的腹神经索对氰戊菊酯表现了2-3倍的神经不敏感性。HJ-R种群对氨基甲酸酯类杀虫剂的抗性主要是由代谢机制引起,其中多功能氧化酶可能起主导作用;对菊酯的抗性是由多功能氧化酶、酯酶、以及神经不敏感性几个因子综合作用的结果。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.