Department of Microbiology, Miami University, Oxford, Ohio, USA.
Center for Advanced Microscopy and Imaging, Miami University, Oxford, Ohio, USA.
Infect Immun. 2018 Aug 22;86(9). doi: 10.1128/IAI.00442-18. Print 2018 Sep.
Transcriptional analyses of ATCC 17978 showed that the expression of A1S_2091 was enhanced in cells cultured in darkness at 24°C through a process that depended on the BlsA photoreceptor. Disruption of A1S_2091, a component of the A1S_2088-A1S_2091 polycistronic operon predicted to code for a type I chaperone/usher pilus assembly system, abolished surface motility and pellicle formation but significantly enhanced biofilm formation on plastic by bacteria cultured in darkness. Based on these observations, the A1S_2088-A1S_2091 operon was named the hotoegulated ilus ABCD () operon, with A1S_2091 coding for the PrpA pilin subunit. Unexpectedly, comparative analyses of ATCC 17978 and isogenic mutant cells cultured at 37°C showed the expression of light-regulated biofilm biogenesis and motility functions under a temperature condition that drastically affects BlsA production and its light-sensing activity. These assays also suggest that ATCC 17978 cells produce alternative light-regulated adhesins and/or pilus systems that enhance bacterial adhesion and biofilm formation at both 24°C and 37°C on plastic as well as on the surface of polarized A549 alveolar epithelial cells, where the formation of bacterial filaments and cell chains was significantly enhanced. The inactivation of also resulted in a significant reduction in virulence when tested by using the virulence model. All these observations provide strong evidence showing the capacity of to sense light and interact with biotic and abiotic surfaces using undetermined alternative sensing and regulatory systems as well as alternative adherence and motility cellular functions that allow this pathogen to persist in different ecological niches.
转录分析表明，在 24°C 的黑暗中培养时，ATCC 17978 中 A1S_2091 的表达通过 BlsA 光受体依赖的过程增强。破坏 A1S_2091（预测编码 I 型伴侣/usher 菌毛组装系统的 A1S_2088-A1S_2091 多顺反子操纵子的一个组成部分），会消除表面运动性和菌膜形成，但显著增强了在黑暗中培养的细菌在塑料上的生物膜形成。基于这些观察结果，A1S_2088-A1S_2091 操纵子被命名为热调节菌毛 ABCD（）操纵子，A1S_2091 编码 PrpA 菌毛亚基。出乎意料的是，对在 37°C 培养的 ATCC 17978 和同源突变细胞的比较分析表明，在 BlsA 产生及其光感应活性受到严重影响的温度条件下，光照调节生物膜生物发生和运动功能的表达。这些检测还表明，ATCC 17978 细胞产生替代的光照调节黏附素和/或菌毛系统，可增强细菌在塑料上以及在极性 A549 肺泡上皮细胞表面的黏附和生物膜形成，在这些表面上，细菌丝和细胞链的形成显著增强。失活也导致在使用毒力模型进行测试时毒力显著降低。所有这些观察结果提供了强有力的证据，表明 能够感知光，并使用未确定的替代感应和调节系统以及替代的黏附和运动细胞功能与生物和非生物表面相互作用，使这种病原体能够在不同的生态位中存活。
