The role of Bacillus anthracis germinant receptors in germination and virulence
The role of Bacillus anthracis germinant receptors in germination and virulence
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DOI：
10.1111/j.1365-2958.2009.06972.x
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发表时间：
2010-01-01
影响因子：
3.6
通讯作者：
Hanna, Philip C.
中科院分区：
文献类型：
--
作者：
Carr, Katherine A.;Lybarger, Suzanne R.;Hanna, Philip C.
当位于内膜的受体检测到氨基酸和嘌呤核苷的组合时，炭疽芽孢的营养依赖性萌发受到刺激。炭疽芽孢杆菌产生五种不同的生发受体，GerH, GerK, GerL， GerS和GerX。另外，只表达其中一种受体的等基因突变株被创造出来并进行萌发和毒力测试。在缺乏其他受体的情况下，GerH受体是野生型含肌苷发芽体萌发的必要和充分条件。GerK和GerL在50 mM的l -丙氨酸中足以发芽。当突变体在气管内接种时，除GerX外的任何受体都足以引起完全毒性感染。相反，当皮下接种时，只有GerH受体能够促进完全毒力感染。这些结果表明，感染途径决定了萌发受体的需求。缺乏所有五种萌发受体的突变体也被减弱，并在体外表现出严重的萌发缺陷。总之，这些数据使我们对萌芽的最初时刻有了更深入的了解，并为刺激这一过程所需的信号提供了更详细的画面。
Nutrient-dependent germination of Bacillus anthracis spores is stimulated when receptors located in the inner membrane detect combinations of amino acid and purine nucleoside germinants. B. anthracis produces five distinct germinant receptors, GerH, GerK, GerL, GerS and GerX. Otherwise isogenic mutant strains expressing only one of these receptors were created and tested for germination and virulence. The GerH receptor was necessary and sufficient for wildtype levels of germination with inosine-containing germinants in the absence of other receptors. GerK and GerL were sufficient for germination in 50 mM L-alanine. When mutants were inoculated intratracheally, any receptor, except for GerX, was sufficient to allow for a fully virulent infection. In contrast, when inoculated subcutaneously only the GerH receptor was able to facilitate a fully virulent infection. These results suggest that route of infection determines germinant receptor requirements. A mutant lacking all five germinant receptors was also attenuated and exhibited a severe germination defect in vitro. Together, these data give us a greater understanding of the earliest moments of germination, and provide a more detailed picture of the signals required to stimulate this process.