朱砂叶螨不同抗性品系酯酶同工酶研究

在室内模拟田间药剂的选择压力,用3种不同药剂及其组合(轮用和混用)对朱砂叶螨Tetranychus cinnabarinus 进行抗药性选育.经过40余代的筛选,朱砂叶螨对甲氰菊酯、阿维菌素和哒螨·阿维混剂分别产生了68.5、8.7和6.7倍的抗性;甲氰菊酯和阿维菌素混用和轮用分别对甲氰菊酯产生了5.6倍和28.7倍抗性.朱砂叶螨各品系酯酶同工酶电泳结果和同工酶谱谱带密度扫描表明,与敏感品系相比,各抗性筛选品系的酯酶活性均有不同程度增加;阿维菌素抗性品系活性最强,酯酶带迁移距离明显远于其他抗性品系,表明该品系酯酶体系中存在变构酯酶.     

朱砂叶螨对甲氰菊酯、阿维菌素,哒螨灵及其混剂抗性遗传力的分析(英文)

采用域性状分析法 ,估算了朱砂叶螨对 5种杀螨剂 (3种单剂和 2种混剂 )的抗性现实遗传力 ,并对 5种药剂的抗性风险进行了评估。把采自重庆北碚田间的朱砂叶螨种群 ,在室内不施药情况下饲养 6 0余代 ,以此作为抗性筛选的敏感品系。分别单一连续汰选近 30代 ,朱砂叶螨对甲氰菊酯、阿维菌素、哒螨灵、哒螨 -阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)和甲氰 -阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m)的抗性分别达 6 5 5 5、5 82、1 2 3、5 2 0和 1 4 2 倍 ;抗性现实遗传力分别为 0 2 16 7、0 0 96 7、0 0 130、0 0 80 0和 0 0 172。在实验室选择条件下 ,预计抗性增长 10倍时 ,甲氰菊酯、阿维菌素、哒螨灵、哒螨 -阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)和甲氰 -阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m)分别需要 15、34、333、4 2和 2 0 0代。甲氰菊酯抗性风险较高 ,其次是阿维菌素、哒螨 -阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)、甲氰 阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m) ,哒螨灵抗性风险较低。混剂哒螨 阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)不能延缓朱砂叶螨对两单剂哒螨灵和阿维菌素的抗性发展 ,而混剂甲氰 阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m)却能有效延缓朱砂叶螨对两单剂     

几种杀虫剂对棉铃虫头部酯酶的联合抑制作用

测定了几种药剂及其组合对棉铃虫Helicoverpa armigera头部酯酶活性的独立与联合抑制作用。结果显示：久效磷、敌百虫、呋喃丹对酯酶活性抑制中浓度分别为:2.4443×10^-6、3.4562×10^-7、2.6302×10^-5mol/L。药代动力学分析结果显示:久效磷与呋喃丹对酯酶抑制方式为竞争性抑制,敌百虫为非竞争性抑制。久效磷+敌百虫与敌百虫+呋喃丹两种药剂组合处理后,对酯酶抑制均增强,抑制中浓度分别为:1.0846×10^-6、5.1786×10^-6mol/L,对酯酶的抑制作用属非竞争性抑制作用。而久效磷+呋喃丹组合对酯酶抑制活性相加,为竞争性抑制作用。结果说明杀虫剂与酯酶的药代动力学互作对混剂的酯酶的抑制作用方式和活性具有重要影响。     

朱砂叶螨抗药性监测

本文采用药膜法建立了朱砂叶螨Tetranychus cinnabarinus（Boisduval）对5种杀螨剂的敏感基线,并对6个不同地理种群的朱砂叶螨进行了抗药性监测,结果表明：5种药剂杀螨活性由高到低分别为阿维菌素〉丁氟螨酯〉氧化乐果〉炔螨特〉甲氰菊酯,其对朱砂叶螨雌成螨的LC50值分别为0.08、2.19、67.89、201.19和605.27mg/L;朱砂叶螨各地理种群已对甲氰菊酯和炔螨特产生了低、中水平的抗性,其抗性倍数分别介于2.93～16.22与4.85～14.35之间,其中云南种群对这2种杀螨剂抗性最高,对氧化乐果与丁氟螨酯处于敏感性降低阶段,其抗性倍数分别介于2.35～4.26与1.56～2.11之间,对阿维菌素还未产生明显抗性;对阿维菌素和甲氰菊酯的增效剂生物测定结果表明,三类解毒酶系（多功能氧化酶、谷胱甘肽S-转移酶和酯酶）都不同程度地参与了朱砂叶螨抗药性的形成。     

朱砂叶螨对甲氨菊酯、阿维菌素，哒螨灵及其混剂抗性遗传力的分析

采用域性状分析法,估算了朱砂叶螨对5种杀螨剂(3种单剂和2种混剂)的抗性现实遗传力,并对5种药剂的抗性风险进行了评估。把采自重庆北碚田间的朱砂叶螨种群,在室内不施药情况下饲养60余代,以此作为抗性筛选的敏感品系。分别单一连续汰选近30代,朱砂叶螨对甲氰菊酯、阿维菌素、哒螨灵、哒螨—阿维(哒螨灵：阿维菌素＝7．4：0．1,m/m)和甲氰—阿维(甲氰菊酯：阿维菌素＝8．9：0．1,m/m)的抗性分别达65．55、5．82、1．23、5．20和1．42．倍;抗性现实遗传力分别为0．2167、0．0967、0．0130、0．0800和0．0172。在实验室选择条件下,预计抗性增长10倍时,甲氰菊酯、阿维菌素、哒螨灵、哒螨—阿维(哒螨灵：阿维菌素＝7．4：0．1,m/m)和甲氰—阿维(甲氰菊酯：阿维菌素＝8．9：0．1,m/m)分别需要15、34、333、42和200代。甲氰菊酯抗性风险较高,其余是阿维菌素、哒螨—阿维(哒螨灵：阿维菌素＝7．4：0．1,m/m)、甲氰-阿维(甲氰菊酯：阿维菌素＝8．9：0．1,m/m),哒螨灵抗性风险较低。混剂哒螨-阿维(哒螨灵：阿维菌素＝7．4：0．1,m/m)不能延缓朱砂叶螨对两单剂哒螨灵和阿维菌素的抗性发展,而混剂甲氰-阿维(甲氰菊酯：阿维菌素＝8．9：0．1,m/m)却能有效延缓朱砂叶螨对两单剂甲氰菊酯和阿维菌素的抗性发展。     

几种杀虫剂对酢浆草如叶螨的毒力及增效作用研究

采用药膜法,研究了甲氰菊酯、氧乐果及毒死蜱对酢浆草如叶螨的毒力及增效作用。结果表明,酢浆草如叶螨对氧乐果最敏感,LC_(50)为28.48 mg/L,甲氰菊酯次之,LC_(50)为394.55 mg/L,毒死蜱最不敏感,LC_(50)高达5876.43 mg/L;增效试验表明,磷酸三苯酯(TPP)、增效醚(PBO)及顺丁烯二酸二乙酯(DEM)对3种杀虫剂均有一定的增效作用,总体上,TPP的增效最好,PBO次之,DEM增效作用稍差。因此,氧乐果和甲氰菊酯对酢浆草如叶螨有较好防治作用,应减少毒死蜱使用;酯酶、多功能氧化酶及谷胱甘肽S-转移酶是该螨最重要的解毒代谢酶。     

二斑叶螨对七种杀螨剂的抗药性测定及其机理研究

室内测定了相对敏感种群(S)和抗性种群(R)对常用7种杀螨剂的敏感性,并测定了羧酸酯酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶3种酶的比活力。结果表明:二斑叶螨Tetranychus urticae Koch R种群已对甲氰菊酯和哒螨灵产生了抗性,抗性倍数分别为5.45和105.47。其中,甲氰菊酯对雌成螨的毒力最低(>3000mg/L),已远远超过田间推荐剂量,不宜继续使用。酶活测定结果表明:谷胱甘肽S-转移酶解毒活性的提高是二斑叶螨对甲氰菊酯产生抗性的原因之一;二斑叶螨对哒螨灵抗性的增强可能与羧酸酯酶有关。     

双去甲氧基姜黄素对朱砂叶螨的生物活性及作用方式

在室温26℃±1℃、湿度60%～80%、光照14 h条件下,测定了天然植物活性成分双去甲氧基姜黄素对重要植食性害螨朱砂叶螨各螨态的触杀和熏蒸活性,对幼螨、若螨、成螨的驱避活性,以及对雌成螨的产卵抑制活性.采用玻片浸渍法测得双去甲氧基姜黄素对朱砂叶螨雌成螨48 h的LCso为0.433 mg·mL-1.在0.883 mg·mL-1(LC70)的浓度下,双去甲氧基姜黄素对朱砂叶螨不同螨态触杀活性的大小依次为幼螨＞若螨＞成螨＞卵,其中对幼螨24h和48 h的校正死亡率分别为60.0%和83.3%;对朱砂叶螨各螨态的熏蒸作用不明显,024h和48 h的校正死亡率均小于3%;对幼螨、若螨以及成螨均表现出较强的驱避作用,其中对幼螨的效果最好,不同处理时间的驱避率均在85%以上,其次是若螨,对成螨的驱避性相对较差,72 h的驱避率仅为47.8%.同时对雌成螨有明显的产卵抑制作用,处理后120 h产卵抑制率达到89.3%.表明双去甲氧基姜黄素对朱砂叶螨的主要作用方式为触杀、驱避和产卵抑制作用.     

十种杀螨剂对朱砂叶螨不同发育阶段的毒力比较

【目的】为明确不同杀螨剂对朱砂叶螨Tetranychuscinnabarinus不同发育阶段的生物活性。【方法】采用浸渍法分别测定了10种杀螨剂对朱砂叶螨成螨、卵和若螨的毒力。【结果】丁氟螨酯、阿维菌素和联苯肼酯对成螨、卵和若螨的活性均较高;乙螨唑和螺螨酯对卵和若螨活性较高,但对成螨活性明显偏低;甲氰菊酯对成螨和若螨的活性优于卵;唑螨酯、哒螨灵和三唑锡对3种螨态也均具有毒杀作用,但毒力偏低。同一种杀螨剂对若螨的活性均高于成螨和卵,乙螨唑、螺螨酯、联苯肼酯、唑螨酯和炔螨特对卵的活性高于成螨,丁氟螨酯、阿维菌素、甲氰菊酯、哒螨灵和三唑锡对成螨的活性高于卵。【结论】不同杀螨剂对朱砂叶螨不同发育阶段毒力存在较大差异,田间用药防治时应根据害螨发生情况和发生阶段,选择适合的防治药剂。     

朱砂叶螨对三种杀螨剂的抗性选育与抗性风险评估

为评价朱砂叶螨Tetranychus cinnabarinus对3种杀螨剂的抗性风险,在实验室抗性品系选育基础上,应用数量遗传学中的域性状分析法,研究了朱砂叶螨北碚种群对甲氰菊酯、阿维菌素和哒螨灵3种杀螨剂的抗性现实遗传力,并对3种药剂在不同杀死率下抗性发展的速率进行了预测。结果表明：分别单一连续汰选16代后,朱砂叶螨对甲氰菊酯、阿维菌素的抗性倍数分别达26.54和4.51倍,对哒螨灵表现为敏感性降低（抗性倍数为1.16倍）;朱砂叶螨对甲氰菊酯、阿维菌素和哒螨灵的抗性现实遗传力分别为0.2472,0.1519和0.0160。在室内选择条件下,杀死率为50%～90%时,要获得10倍抗性,甲氰菊酯仅需要13～6代,阿维菌素需要约21～10代;哒螨灵需要约197～89代;在田间选择,三种药剂都将需要更长的时间。抗性筛选16代结果表明,抗性风险较高的是菊酯类的甲氰菊酯,其次是生物源农药阿维菌素,杂环类的哒螨灵抗性风险较小。试验结果可为朱砂叶螨抗性治理提供参考。     

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.