Soybean Genomics and Improvement Laboratory, USDA-ARS , Beltsville, Maryland 20705, United States.
J Proteome Res. 2012 Mar 2;11(3):1720-7. doi: 10.1021/pr200933d. Epub 2012 Feb 8.
Salmonella enterica, a bacterial, food-borne pathogen of humans, can contaminate raw fruits and vegetables. Unfortunately for consumers, the bacteria can survive in water used to wash away contaminating bacteria. The ability to survive the low-osmotic conditions of the wash water is attributed to the OpgGH operon that leads to the production of osmotically regulated periplasmic glucans. Mutants lacking OpgGH grow slowly under low-osmotic conditions, but there are also unexpected traits such as abnormal flagellar motility and reduced virulence in mice. To get a broader understanding of these pleiotropic effects under low osmolarity, we examined the proteome of these mutants using high-throughput mass spectrometry. We identified approximately one-third of the proteins encoded by the genome and used label-free spectral counting to determine the relative amounts of proteins in wild-type cultures and mutants. Mutants had reduced amounts of proteins required for osmotic sensing, flagellar motility, purine and pyrimidine metabolism, oxidative energy production, and protein translation. By contrast, mutants had greater amounts of ABC transporters needed to balance cellular osmolarity. Hence, the effects of OpgGH reach across the proteome, and the data are consistent with the mutant phenotypes.
肠道沙门氏菌是一种人类食源性病原体细菌，能够污染生的水果和蔬菜。不幸的是，对于消费者来说，细菌可以在用于冲洗掉污染细菌的水中存活。这种在洗水低渗透压条件下存活的能力归因于 OpgGH 操纵子，它导致产生渗透压调节的周质葡聚糖。缺乏 OpgGH 的突变体在低渗透压条件下生长缓慢，但也有一些意想不到的特征，如异常的鞭毛运动和在小鼠中的毒力降低。为了更广泛地了解低渗透压下这些多效性效应，我们使用高通量质谱法检查了这些突变体的蛋白质组。我们鉴定了大约三分之一由基因组编码的蛋白质，并使用无标记谱计数法确定了野生型培养物和突变体中蛋白质的相对含量。突变体中与渗透压感应、鞭毛运动、嘌呤和嘧啶代谢、氧化能量产生以及蛋白质翻译相关的必需蛋白的含量减少。相比之下，突变体中需要更多的 ABC 转运蛋白来平衡细胞渗透压。因此，OpgGH 的影响跨越了蛋白质组，数据与突变体表型一致。
