一株对蜱致病性球孢白僵菌的分子鉴定

球孢白僵菌作为一种很重要的生防真菌,已被广泛用于农业害虫和蜱的防控。对前期筛选得到的具有生防潜力的杀蜱真菌B.bAT17用PCR进行分子鉴定,结果经登录GenBank检索表明,所持菌株与JF429895.1、AJ564812.1、AB027382 100%同源,为有效利用球孢白僵菌对蜱虫进行生物防控提供科学指导。     

溴氰菊酯对微小牛蜱的敏感度和对雌蜱产卵的影响的研究

１９９１～１９９２年在福建省研究溴氰菊酯对微小牛蜱各变态期的敏感度和对饱血雌蜱产卵情况的影响。结果表明，幼蜱对溴氰菊酯最敏感，当施用浓度为５ｐｐｍ时，幼蜱平均死亡率为１００％；若蜱其次，死亡率２８．９％；未吸虫成蜱敏感度最低，死亡率仅１０％。据Ｘ２检验，微小牛蜱在不同变态期间对溴氰菊酯的敏感度差异极显著（Ｐ＜０．０１）。饱血雌蜱接触溴氰菊酯１０μｇ／虫后，其产卵前期比对照蜱延长６天，产卵期缩短６天，产卵量减少２１８８粒。     

微小牛蜱唾液菌群的PCR-DGGE分析

为了解微小牛蜱唾液内的菌群结构信息,采用PCR-DGGE技术对微小牛蜱半饱血、饱血雌成虫唾液内菌群结构进行了分析和比较,结果表明:微小牛蜱半饱血、饱血雌成虫唾液内菌群结构有较大差异,饱血中细菌比半饱血多两种,分别为莫拉菌和不动杆菌;唾液内菌群与全蜱菌群差异极大。在检出的细菌中多数具有一定的致病性,故微小牛蜱叮咬可能会引起人或动物发生多种细菌性疾病。     

微小牛蜱细胞培养技术

微小牛蜱是多种人兽共患的自然疫原性疾病的媒介,蜱细胞培养与细胞系的建立是其分子生物学研究及其传播疾病研究的常用手段.微小牛蜱细胞培养比较适宜的培养基为Grace、Schneider、L15、M119等培养基.论文比较系统地介绍了利用蜕皮前的幼蜱、成蜱卵巢、饱血雌蜱的血淋巴组织等材料体外培养微小牛蜱细胞的试验技术.     

微小牛蜱铁蛋白编码基因的克隆和分析

从微小牛蜱克隆到1个新的铁蛋白编码基因，cDNA全长642bp，编码区为123-639bp，编码172个氨基酸残基，该蛋白预测的分子量为19．9ku，等电点为4．24。经过分析，其预测氨基酸序列与已报道的变异革蜱、非洲钝缘蜱和蓖子硬蜱铁蛋白同源性分别为93．60％、88．37％和83．72％。且核苷酸序列在mRNA 5’未翻译区(5’UTR)的茎环结构存在铁应答元件(IRE)，其氨基酸序列上带有典型的亚铁氧化酶中心结构的保守序列。RT-PCR分析表明，该基因在微小牛蜱卵、幼蜱、半饱血雌蜱、饱血雌蜱和雄蜱这几个阶段均有表达。     

微小牛蜱生物学特性的研究

<正> 多年来,盱眙县牛双芽巴贝西虫病时有发生,造成危害。控制本病的措施之一是消灭微小牛蜱,而欲达到这一目的,对微小牛蜱的生物学特性的研究,并积累一些其在自然界消长规律的资料是一项必不可少的基础工作。为此,我们在1987年～1989年进行如下的工作。1 材料与方法1.1 试验材料采集寄生在牛体外表的硬蜱类及实验室常规用器皿。     

牛蜱龙岩分离株的分子鉴定

为了解福建省龙岩地区牛场体表蜱的种类,试验采集龙岩地区牛体表寄生蜱样本,基于蜱的核糖体rDNA内转录间隔区(internal transcribed spacer,ITS)序列PCR扩增方法进行分子鉴定,获得ITS1和ITS2基因序列,进行blastn相似性搜索,应用MegAlign和MEGA 7.0软件完成同源性分析及种系发育分析。结果表明,该蜱ITS1序列与中国甘肃微小扇头蜱分离株同源性达99.32%(JQ737124.1、JQ737125.1),与中国湖南微小扇头蜱HAI2分离株同源性达99.16%(MK224531.1);ITS2序列与中国河南、南非豪登微小扇头蜱分离株同源性均为100%(KX450287.1、KY457506.1);种系发育分析结果显示,龙岩地区牛体表分离的牛蜱ITS基因序列与扇头蜱属ITS基因序列聚类,与革蜱属和璃眼蜱属处于两个不同的分支。说明福建龙岩牛蜱分离株为微小扇头蜱。     

生物灭虫剂对牛体微小牛蜱的杀灭效果观察

生物灭虫剂对牛体微小牛蜱的杀灭效果观察李树荣陈刚＊舒相华杜文昌丁路祥（云南农业大学动科院，昆明，６５０２０１）（寻甸县塘子镇畜牧兽医站，６５５２０３）微小牛蜱Ｂｏｏｐｈｉｌｕｓｍｉｃｒｏｐｌｕｓ（Ｃａｎｅｓｔｒｉｎｉ，１８８７）是世界性广布种之一。是...     

Attitudes and practices of Queensland dairy farmers to the control of the cattle tick, Boophilus microplus

Objective To determine practices for the control of cattle ticks on dairy farms in Queensland, the attitudes of farmers to tick infestations and to identify opportunities for and barriers against the introduction of non-chemical methods of tick control.
Design A survey of 199 dairy farmers from tick-infested parts of Queensland was undertaken by 20 dairy advisers and stock inspectors from October 1996 to June 1997. The sample was a proportional, random selection of dairy farms from four regions. A personal interview was conducted with each farmer and answers to 134 questions were obtained.
Results and conclusions Most farmers were not concerned by cattle ticks on their own farms, although they believed that ticks are important to the dairy industry. They were most concerned about the development of chemical resistance by cattle ticks. Inadequate facilities and lack of motivation appeared to be the factors most limiting to improving the methods of control. Most farmers claimed to have only small numbers of ticks at worst. Although a control program recom mended by the Queensland Dairyfarmers' Organisation was well regarded by farmers, few had adopted it. Many farmers saw no need to implement a strategic control program.     

微小牛蜱Bm91基因的原核表达

根据GenBank收录的微小牛蜱Bm91基因序列设计一对表达引物,以微小牛蜱幼蜱总RNA反转录合成的cDNA为模板,扩增获得了Bm91基因,其长度为1 908 bp,包含一个大小为1 833 bp的完整开放阅读框,编码611个氨基酸,该蛋白预期分子质量为83 ku。将Bm91基因片段亚克隆到原核表达载体pET-30a,构建重组原核表达载体pET-30a-Bm91,转化BL21宿主菌,经IPTG诱导,发现在0.8 mmol/LIPTG,诱导时间2 h,温度37℃条件下,目的重组蛋白表达量最大,约占蛋白总量的20%。SDS-PAGE检测表明,表达产物为分子质量为83 ku的融合蛋白,与预期大小一致;Western blot分析表明,表达产物能被兔抗微小牛蜱阳性血清所识别。     

微小牛蜱Bm86基因的真核表达

采用RT-PCR技术从微小牛蜱饥饿幼蜱破解物中扩增到Bm86基因，将其与巴斯德毕赤酵母分泌型表达载体pPlC9K重组构建了重组表达载体pPIC9K-Bm86，测序正确后将其用SacⅠ内切酶线性化后采用电穿孔法转化巴斯德毕赤酵母菌Gs115，经G418抗性筛选高拷贝重组菌株后用甲醇诱导表达，SDSPAGE和Western-blotting分析结果表明，诱导表达的培养上清液中表达出具有反应活性的68ku重组Bm86蛋白，目的蛋白约占培养上清液中蛋白总量的32％以上，诱导96h目的蛋白的表达量为0．36mg／mL。     

Effect of breed of cattle on innate resistance to infection with Anaplasma marginale transmitted by Boophilus microplus

OBJECTIVE: To assess the innate resistance of and transmission in naive Bos taurus cross Bos indicus and purebred Bos indicus cattle when placed in a paddock with cattle infected with Anaplasma marginale and carrying Boophilus microplus ticks. DESIGN: A group of 49 purebred B indicus, and 48 B indicus cross B taurus (50%, F1 generation) 24-month-old steers were kept in the same paddock with cattle artificially infected with a virulent isolate of A marginale and Boophilus microplus. The cattle were seronegative for A marginale at the start of the trial but had previously been exposed to Babesia bovis and B bigemina. PROCEDURE: Cattle were inspected twice weekly for 118 days. Whole blood, blood smears and serum samples were collected from the cattle on day 37 after exposure and then at regular intervals to day 83 after exposure to measure packed-cell volumes, parasitaemias and antibody titres to A marginale. Any animals that met preset criteria were treated for anaplasmosis. On day 83 all cattle were treated with an acaricide and cattle infected with A marginale were removed from the rest of the group. RESULTS: A marginale was detected in blood smears from 14 crossbred and 9 B indicus steers between days 56 and 72 after exposure. Five and two of the infected crossbred and B indicus steers required treatment, respectively. One of the Bos indicus cattle died as a result of the A marginale infection despite treatment. Antibodies to A marginale were detected in the 23 infected cattle. The mean packed-cell volume depression was 40 and 37% in the affected crossbred and Bos indicus groups, respectively. There was no significant difference detected in susceptibility between these two groups. CONCLUSIONS: Innate resistance of purebred B indicus and crossbred cattle was not significantly different. The results confirm that purebred B indicus and crossbred cattle are sufficiently susceptible to warrant the use of vaccination against Anaplasma infections.     

白僵菌经不同基质传代后对桑天牛幼虫的侵染力比较

以诱集自土壤中的对桑天牛(Apriona germari)幼虫具有较高致病性的球孢白僵菌(Beauveria bassiana)Bb00菌株为原发菌株R0,通过反复接种桑天牛幼虫分别获得菌株R1、R2、R3和R4,并反复在普通查氏培养基上传代分别获得菌株M1、M2、M3和M4。将R0、R2、R4和M2、M4菌株感染桑天牛幼虫进行生物测定,发现在普通培养基上传代,会导致菌株致病力的降低,而通过桑天牛幼虫传代培养可以提高菌株的致病力。R4、R2、R0、M2、M4菌株的LT50分别为3.23、4.01、4.13、4.78和6.34d,LC50分别为0.686×106、1.470×106、3.050×106、7.940×106和9.580×106mL-1。表明通过菌株在桑天牛幼虫虫体上反复接种可以提高白僵菌对桑天牛幼虫的侵染力。     

Diagnosis of amitraz resistance in Boophilus microplus in New Caledonia with the modified Larval Packet Test

The tick Boophilus microplus represents a serious pathological constraint to livestock production in New Caledonia. Cattle ticks are controlled by chemical application of two acaricides that are currently used in New Caledonia; deltamethrin is used at 46% of the cattle production facilities and amitraz at the remaining 54% premises where resistance to deltamethrin has been identified. In 2003, a modified Larval Packet Test (LPT) was used to conduct a survey for amitraz resistance. Ticks were collected from 29 farms, including farms using deltamethrin (n = 8) or amitraz (n = 21). Of eighteen different tick populations, sixteen populations were defined susceptible to amitraz and two populations were considered amitraz-resistant. This is the first report of populations of B. microplus being resistant to amitraz, using the modified LPT in New Caledonia. A thorough survey of tick susceptibility to amitraz in cattle farms of the country should be conducted to assess the presence of amitraz-resistant populations. The emergence of amitraz resistance so soon after its introduction has some important implications for the strategy and organisation of tick control in New Caledonia, and this paper discusses some of the urgent actions that should be undertaken.     

家蚕抵抗白僵菌感染的机理研究

白僵菌分生孢子在不同抗性品种蚕幼虫体表面,自萌发到侵入的全过程都不形成一个明显象附着胞那样的构造;分生孢子萌发后的侵入情况可观察到三种不同状态;蚕毛窝间隙、气门是自僵菌易侵入的部位之一.不同品种及同一品种不同生长阶段的蚕.对白僵菌的感染性存在差异.家蚕体壁的表面构造,化学性质的防御反应,以及家蚕血液对白僵菌发育、增殖的影响.是造成此差异的机理之一.     

生物防治白僵菌与家蚕病原白僵菌的生物学特性初步比较

对广州市森林保护用生防白僵菌Bb2、华南农业大学保存生防用白僵菌Bb7以及收集自广东省化州蚕种场、化州市笪桥村、翁源县硝村等蚕区的3株家蚕白僵菌分离株(Bb8、Bb13、Bb14),分别用PDA培养基进行分离和扫描电子显微镜观察,并对菌株的生物学特性进行初步比较,为开展家蚕白僵病的病原溯源和防控研究,以及为评估蚕区使用白僵菌农药对养蚕生产安全的影响提供实验依据。结果表明,上述5株白僵菌的菌落形态、营养生长量、产孢量等生物学性状存在差异,生长最快的是Bb2菌株,产孢量最高的是Bb8菌株和Bb13菌株;2株僵蚕蛹来源白僵菌Bb8、Bb14的分生孢子在扫描电子显微镜下呈球形或近球形,二者同为球孢白僵菌[Beauveria bassiana(Bals.)Vuill.]。研究结果还显示部分蚕区的家蚕白僵菌与生物防治用白僵菌有一定程度的生物学特征相似性,而相同地区的家蚕病原白僵菌也存在差异,这暗示广东蚕区家蚕白僵病的病原来源复杂,对于2株生防用白僵菌菌株Bb2、Bb7是否为家蚕病原白僵菌还有待进一步研究。     

不同温湿度对草地螟白僵菌的致病力影响

测试了不同温、湿度下白僵菌(Beauveria bassiana)对草地螟(Loxostege sticticalis)幼虫的致病力。实验设置了17、20、23、26、29℃5个温度水平,相对湿度(95±5)%、(85±5)%、(75±5)%、(65±5)%和(55±5)%5个梯度,用浓度为1×109孢子/mL的白僵菌孢子液感染2龄的草地螟幼虫。结果表明:在温度为26℃时的致死中时(LT50)最短,死亡速度最快,死亡率最高;高于或低于此温度时,草地螟幼虫的LT50延长,死亡速度减慢。相对湿度发生变化时,草地螟幼虫死亡速度和死亡率不同。相对湿度为95%时,棉铃虫死亡速度最快,死亡率最高;相对湿度低于55%时,棉铃虫死亡率显著降低。相对湿度越高,草地螟幼虫死亡速度越快。