Signal transduction systems are essential for microorganisms to respond to their ever-changing environment. They can be distinguished into one-component systems, two-component systems, and extracytoplasmic-function σ factors. Abundances of a few signal-transducing proteins, termed herein as sensory proteins (SPs), have previously been reported to be correlated with the genome size and ecological niche of certain Gram-positive bacteria. No such reports are available for Gram-negative bacteria. The current study attempts to investigate the relationship of the abundances of SPs to genome size in Escherichia coli, and the bacterial pathotypes or phylotypes. While the relationship between SP abundance and genome size could not be established, the sensory protein index (SPI), a new metric defined herein, was found to be correlated with E. coli virulence. In addition, significant association was observed among the distribution of SPs and E. coli pathotypes. Results indicate that such associations might be due to genomic rearrangements to best utilize the resources available in a given ecological niche. Overall, the study provides an in-depth analysis of the occurrence of different SPs among pathogenic and nonpathogenic E. coli strains. Possibilities of using the SPI as a marker for identifying pathogenic strains from among an organism complex are also discussed.

中文翻译：

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致病性和非致病性细菌可以通过感官蛋白丰度区分吗？

信号转导系统对于微生物应对不断变化的环境至关重要。它们可以区分为一组分系统，二组分系统和胞浆外功能σ因子。先前已经报道了几种信号转导蛋白的丰度，在本文中称为感觉蛋白（SP），其与某些革兰氏阳性细菌的基因组大小和生态位有关。没有有关革兰氏阴性菌的报道。目前的研究试图调查大肠埃希氏菌中SP的丰度与基因组大小的关系。，以及细菌的病理型或系统型。虽然无法确定SP丰度与基因组大小之间的关系，但发现本文定义的新指标“感觉蛋白指数（SPI）”与大肠杆菌的毒力相关。另外，在SPs和大肠杆菌致病型的分布之间观察到显着关联。结果表明，这种关联可能是由于基因组重排以最佳利用给定生态位中的可用资源。总体而言，该研究提供了对病原性和非病原性大肠杆菌菌株中不同SP发生情况的深入分析。还讨论了使用SPI作为标记物从生物复合物中鉴定致病菌株的可能性。