Molecular detection and genetic diversity of Bartonella species in large ruminants and associated ectoparasites from the Brazilian Cerrado

Currently, five Bartonella species and an expanding number of Candidatus Bartonella species have globally been reported in ruminants. Likewise, different Bartonella genotypes were identified. However, studies relating to ruminant‐associated Bartonella in Brazil are scarce. The current study aimed to assess the prevalence and genetic diversity of Bartonella in cattle, buffaloes and associated ectoparasites in Brazil. For this purpose, EDTA‐blood samples from 75 cattle and 101 buffaloes were sampled. Additionally, 128 Rhipicephalus microplus and one Amblyomma sculptum ticks collected from cattle, and 197 R. microplus, one A. sculptum and 170 lice (Haematopinus tuberculatus) collected from buffaloes were included. Bartonella DNA was initially screened through an HRM real‐time PCR assay targeting the 16S–23S internal transcribed spacer (ITS), and the positive samples were submitted to an additional HRM assay targeting the ssrA gene. The HRM‐positive amplicons were sequenced, and the nucleotide identity was assessed by BLASTn. Bartonella spp.‐positive DNA samples were analysed by conventional PCR assays targeting the gltA and rpoB genes, and then, the samples were cloned. Finally, the phylogenetic positioning and the genetic diversity of clones were assessed. Overall, 21 of 75 (28%) cattle blood samples and 13 of 126 (10.3%) associated ticks were positive for Bartonella bovis. Out of 101 buffaloes, 95 lice and 188 tick DNA samples, one (1%) buffalo and four (4.2%) lice were positive for Bartonella spp. Conversely, none of the ticks obtained from buffaloes were positive for Bartonella. The Bartonella sequences from buffaloes showed identity ranging from 100% (ITS and gltA) to 94% (ssrA) with B. bovis. In contrast, the Bartonella DNA sequences from lice were identical (100%) to uncultured Bartonella sp. detected in cattle tail louse (Haematopinus quadripertusus) from Israel in all amplified genes. The present study demonstrates the prevalence of new B. bovis genotypes and a cattle lice‐associated Bartonella species in large ruminants and their ectoparasites from Brazil. These findings shed light on the distribution and genetic diversity of ruminant‐ and ectoparasite‐related Bartonella in Brazil.     

镰形扇头蜱IgG结合蛋白基因的克隆与表达分析

本实验以镰形扇头蜱吸血前后雄蜱唾液腺的抑制消减杂交cDNA文库中的EST数据为基础,应用RACE方法从镰形扇头蜱体内克隆出一个IgG(IgG binding protein,IGBP)基因的全长序列,该基因全长683bp,编码178个氨基酸,预测分子量为19.5kDa,经同源性比较该基因与具尾扇头蜱的IGBP-MB基因序列的同源性高达92%。用RT-PCR方法分析了该基因表达的性别特异性、各个器官、不同发育阶段的表达情况,结果表明,该基因表达没有性别特异性;IGBP基因在唾液腺、壳这2个器官有所表达,但在肠中却没有表达;在蜱的各个发育阶段均有表达。     

海南地区血红扇头蜱的生物学特性及对宿主的影响

目的 对野外采集的蜱进行形态学与分子生物学鉴定,确定种属并完成该蜱的实验室人工饲养,研究该蜱虫的生物学特性及其对宿主的影响。方法 在体视镜显微镜下观察蜱的形态学特征,并结合分子生物学的方法扩增蜱虫线粒体16srRNA目的基因,进一步确定蜱的种属;利用改进的实验室人工蜱喂养系统在新西兰白兔体表寄生蜱虫,分析其各时期的形态学变化和生活史特性,最后用全自动血细胞分析仪测定寄生与未寄生新西兰白兔血液的14项血常规指标。结果 根据蜱形态学分析,雌雄蜱的假头基呈六角扇形,腹部肛沟明显,雌蜱腹部可看到明显的生殖孔和肛门,具有明显的缘垛;PCR扩增16srRNA 1.5%琼脂糖凝胶在约460 bp处有目的条带,确定野外采集蜱为血红扇头蜱（Rhipicephalus sanguineus）。在相对温度28℃,相对湿度（90±5）%的实验室环境下,血红扇头蜱发育1个完整的世代需要61～83 d,并表现出宿主单一性,即在不更换宿主的情况下,幼蜱、若蜱和成蜱均在新西兰白兔上寄生;新西兰白兔寄生蜱6次后,体质量和体温降低,白细胞数（WBC）、淋巴细胞百分比率（LYM）等升高。结论 在相对温度28℃,相对湿度（9...