Nonselective Persistence of a Rickettsia conorii Extrachromosomal Plasmid during Mammalian Infection.
Nonselective Persistence of a Rickettsia conorii Extrachromosomal Plasmid during Mammalian Infection.
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哺乳动物感染期间康氏立克次体染色体外质粒的非选择性持续存在。
DOI：
10.1128/iai.01205-15
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发表时间：
2016
影响因子：
3.1
通讯作者：
Martinez,JuanJ
中科院分区：
文献类型：
--
作者：
Riley,SeanP;Fish,AbigailI;Garza,DanielA;Banajee,KaikhushrooH;Harris,EmmaK;delPiero,Fabio;Martinez,JuanJ
随着可行的遗传工具的出现，对立克次体属的科学分析正在经历一个快速变化的时期。这些致病菌诱变工具的发展将允许立克次体发病机制的遗传分析。尽管取得了这些进展，仍然存在不确定性，关于使用质粒来研究这些细菌invivomammalian感染模型，即，潜在的毒力变化与存在的染色体外DNA和非选择性持久性的质粒在哺乳动物感染模型。在这里，我们描述了用质粒pRam18dRGA[AmTrCh]转化康氏立克次体Malish 7。变形河conorii在感染的细胞培养物中稳定地维持该质粒，表达编码的荧光蛋白，并且在细胞培养物中表现出与未转化的R.科诺里。使用一个建立良好的致命性地中海斑点热小鼠模型，我们证明，R。conorii（pRam 18 dRGA [AmTrCh]）在动物中引起与其未转化的对应物相同的致命结果，重要的是，在没有选择性抗生素压力的情况下，在整个感染过程中维持质粒。有趣的是，质粒转化的R.在内皮细胞和循环白细胞中都容易观察到Conorii。总之，我们的数据表明，在致病性立克次体物种中存在的染色体外DNA元件不会影响疾病模型中的体外增殖或体内感染性，并且质粒如pRam18dRGA[AmTrCh]是进一步遗传操纵致病性立克次体的有价值的工具。
Scientific analysis of the genus Rickettsia is undergoing a rapid period of change with the emergence of viable genetic tools. The development of these tools for the mutagenesis of pathogenic bacteria will permit forward genetic analysis of Rickettsia pathogenesis. Despite these advances, uncertainty still remains regarding the use of plasmids to study these bacteria inin vivomammalian models of infection, namely, the potential for virulence changes associated with the presence of extrachromosomal DNA and nonselective persistence of plasmids in mammalian models of infection. Here, we describe the transformation of Rickettsia conorii Malish 7 with the plasmid pRam18dRGA[AmTrCh]. Transformed R. conorii stably maintains this plasmid in infected cell cultures, expresses the encoded fluorescent proteins, and exhibits growth kinetics in cell culture similar to those of nontransformed R. conorii. Using a well-established murine model of fatal Mediterranean spotted fever, we demonstrate that R. conorii(pRam18dRGA[AmTrCh]) elicits the same fatal outcomes in animals as its untransformed counterpart and, importantly, maintains the plasmid throughout infection in the absence of selective antibiotic pressure. Interestingly, plasmid-transformed R. conorii was readily observed both in endothelial cells and within circulating leukocytes. Together, our data demonstrate that the presence of an extrachromosomal DNA element in a pathogenic rickettsial species does not affect eitherin vitroproliferation orin vivoinfectivity in models of disease and that plasmids such as pRam18dRGA[AmTrCh] are valuable tools for the further genetic manipulation of pathogenic rickettsiae.