Predation by Bdellovibrio bacteriovorus HD100 requires type IV pili
Predation by Bdellovibrio bacteriovorus HD100 requires type IV pili
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DOI：
10.1128/jb.01942-06
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发表时间：
2007-07-01
影响因子：
3.2
通讯作者：
Sockett, R. Elizabeth
中科院分区：
文献类型：
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作者：
Evans, Katy J.;Lambert, Carey;Sockett, R. Elizabeth
早期电子显微镜和我们在Bdellovibrio bacteriovorus细胞实验室中的研究表明，这种异常掠食性细菌的非纤维球极纤维存在狭窄。分析细菌杆菌HD100基因组显示了一组可能编码IV型Pili的基因，并且针对FLP Pili的不完整基因；因此，研究了IV型Pili型在芽孢杆菌HD100的掠食性生命周期中的作用。预测的PILA蛋白与已知IV型PILIN的比对显示了IVA型Pilins共有的特征保守的N末端。编码IV型Pilus纤维蛋白的PIL4基因在多个Bdellovibrio复制培养物中被插入失活，并通过逆转录酶PCR监测对其他pilus基因表达的影响。在液体猎物培养物和固定的黄色荧光蛋白标记的猎物中废除了复制分离株中PIL4的中断bdellovibrio掠食能力，但可以独立地培养突变体。在整个腹部腹膜上bdelloplast阶段到猎物裂解和猎物无关的生长，在整个掠食性生命周期中介绍了参与IV型PILI形成的PIL基因的表达模式。综上所述，数据表明该类型IV pili在Bdellovibrio捕食中起着至关重要的作用。
Early electron microscopy and more recent studies in our laboratory of Bdellovibrio bacteriovorus cells indicated the presence of narrow fibers at the nonflagellar pole of this unusual predatory bacterium. Analysis of the B. bacteriovorus HD100 genome showed a complete set of genes potentially encoding type IV pili and an incomplete gene set for Flp pili; therefore, the role of type IV pili in the predatory life cycle of B. bacteriovorus HD100 was investigated. Alignment of the predicted PilA protein with known type IV pilins showed the characteristic conserved N terminus common to type IVa pilins. The piL4 gene, encoding the type IV pilus fiber protein, was insertionally inactivated in multiple Bdellovibrio replicate cultures, and the effect upon the expression of other pilus genes was monitored by reverse transcriptase PCR. Interruption of piL4 in replicate isolates abolished Bdellovibrio predatory capability in liquid prey cultures and on immobilized yellow fluorescent protein-labeled prey, but the mutants could be cultured prey independently. Expression patterns of pil genes involved in the formation of type IV pili were profiled across the predatory life cycle from attack phase predatory Bdellovibrio throughout the intraperiplasmic bdelloplast stages to prey lysis and in prey-independent growth. Taken together, the data show that type IV pili play a critical role in Bdellovibrio predation.