Selle Kurt, Goh Yong J, Johnson Brant R, O'Flaherty Sarah, Andersen Joakim M, Barrangou Rodolphe, Klaenhammer Todd R
Functional Genomics Graduate Program, North Carolina State UniversityRaleigh, NC, USA.
Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State UniversityRaleigh, NC, USA.
Front Microbiol. 2017 Apr 11;8:553. doi: 10.3389/fmicb.2017.00553. eCollection 2017.
NCFM is a well-characterized probiotic microorganism, supported by a decade of genomic and functional phenotypic investigations. deficient in lipoteichoic acid (LTA), a major immunostimulant in Gram-positive bacteria, has been shown to shift immune system responses in animal disease models. However, the pleiotropic effects of removing LTA from the cell surface in lactobacilli are unknown. In this study, we surveyed the global transcriptional and extracellular protein profiles of two strains of deficient in LTA. Twenty-four differentially expressed genes specific to the LTA-deficient strains were identified, including a predicted heavy metal resistance operon and several putative peptidoglycan hydrolases. Cell morphology and manganese sensitivity phenotypes were assessed in relation to the putative functions of differentially expressed genes. LTA-deficient exhibited elongated cellular morphology and their growth was severely inhibited by elevated manganese concentrations. Exoproteomic surveys revealed distinct changes in the composition and relative abundances of several extracellular proteins and showed a bias of intracellular proteins in LTA-deficient strains of . Taken together, these results elucidate the impact of deletion on the transcriptome and extracellular proteins of , suggesting roles of LTA in cell morphology and ion homeostasis as a structural component of the Gram positive cell wall.
NCFM是一种特征明确的益生菌微生物，有十年的基因组和功能表型研究作为支撑。缺乏脂磷壁酸（LTA），革兰氏阳性菌中的一种主要免疫刺激剂，已被证明在动物疾病模型中会改变免疫系统反应。然而，在乳酸杆菌中从细胞表面去除LTA的多效性作用尚不清楚。在本研究中，我们调查了两株缺乏LTA的菌株的全局转录和细胞外蛋白质谱。鉴定出了24个LTA缺陷菌株特有的差异表达基因，包括一个预测的重金属抗性操纵子和几种假定的肽聚糖水解酶。根据差异表达基因的假定功能评估了细胞形态和锰敏感性表型。缺乏LTA的菌株呈现出细长的细胞形态，并且其生长受到锰浓度升高的严重抑制。蛋白质组学调查揭示了几种细胞外蛋白质的组成和相对丰度的明显变化，并显示出LTA缺陷菌株中细胞内蛋白质的偏向性。综上所述，这些结果阐明了LTA缺失对菌株转录组和细胞外蛋白质的影响，表明LTA作为革兰氏阳性细胞壁的结构成分在细胞形态和离子稳态中的作用。
