Budachetri Khemraj, Gaillard Daniel, Williams Jaclyn, Mukherjee Nabanita, Karim Shahid
Department of Biological Sciences, University of Southern Mississippi, 118 College Drive #5018, Hattiesburg, MS 39406, USA.
Department of Biological Sciences, University of Southern Mississippi, 118 College Drive #5018, Hattiesburg, MS 39406, USA.
Ticks Tick Borne Dis. 2016 Oct;7(6):1225-1229. doi: 10.1016/j.ttbdis.2016.07.010. Epub 2016 Jul 20.
The gopher tortoise tick, Amblyomma tuberculatum, has a unique relationship with the gopher tortoise, Gopherus polyphemus, found in sandy habitats across the southeastern United States. We aimed to understand the overall bacterial community associated with A. tuberculatum while also focusing on spotted fever group Rickettsia. These tortoises in the Southern Mississippi region are a federally threatened species; therefore, we have carefully trapped the tortoises and removed the species-specific ticks attached to them. Genomic DNA was extracted from individual ticks and used to explore overall bacterial load using pyrosequencing of bacterial 16S rRNA on 454-sequencing platform. The spotted fever group of Rickettsia was explored by amplifying rickettsial outer membrane protein A (rompA) gene by nested PCR. Sequencing results revealed 330 bacterial operational taxonomic units (OTUs) after all the necessary curation of sequences. Four whole A. tuberculatum ticks showed Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes as the most dominant phyla with a total of 74 different bacterial genera detected. Together Rickettsiae and Francisella showed >85% abundance, thus dominating the bacterial community structure. Partial sequences obtained from ompA amplicons revealed the presence of an uncharacterized Rickettsia similar to the Rickettsial endosymbiont of A. tuberculatum. This is the first preliminary profile of a complete bacterial community from gopher tortoise ticks and warrants further investigation regarding the functional role of Rickettsial and Francisella-like endosymbionts in tick physiology.
地鼠陆龟蜱（Amblyomma tuberculatum）与地鼠陆龟（Gopherus polyphemus）有着独特的关系，地鼠陆龟分布于美国东南部的沙地栖息地。我们旨在了解与地鼠陆龟蜱相关的整体细菌群落，同时重点关注斑点热群立克次体。密西西比州南部地区的这些陆龟是联邦濒危物种；因此，我们小心地捕获了陆龟，并移除附着在它们身上的特定物种蜱。从单个蜱中提取基因组DNA，并使用454测序平台上细菌16S rRNA的焦磷酸测序来探索整体细菌载量。通过巢式PCR扩增立克次体外膜蛋白A（rompA）基因来探索斑点热群立克次体。测序结果显示，在对所有序列进行必要的整理后，有330个细菌操作分类单元（OTU）。四只完整的地鼠陆龟蜱显示，变形菌门、厚壁菌门、放线菌门和拟杆菌门是最主要的门类，总共检测到74个不同的细菌属。立克次体属和弗朗西斯菌属的总和显示丰度>85%，因此主导了细菌群落结构。从ompA扩增子获得的部分序列显示存在一种未鉴定的立克次体，类似于地鼠陆龟蜱的立克次体内共生体。这是地鼠陆龟蜱完整细菌群落的首个初步概况，有必要进一步研究立克次体属和弗朗西斯菌属样内共生体在蜱生理学中的功能作用。
