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首页> 外文期刊>Journal of bacteriology >Generation of Metabolically Diverse Strains of Streptococcus pyogenes during Survival in Stationary Phase
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Generation of Metabolically Diverse Strains of Streptococcus pyogenes during Survival in Stationary Phase

机译：化脓性链球菌的代谢多样化菌株在静止期生存期间的产生。

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Streptococcus pyogenes, in addition to causing fulminant disease, can be carried asymptomatically and may survive in the host without causing disease. Long-term stationary-phase cultures were used to characterize the metabolism of cultures surviving after glucose depletion. Survival of stationary-phase cultures in glucose-depleted rich medium was truncated by switching the cells to phosphate-buffered saline or by the addition of antibiotics, suggesting that survival depended on the presence of nutrients and metabolic activity. The metabolites of the pyruvate-to-acetate (PA) pathway (acetate and formate) and amino acid catabolic pathways (ammonia) accumulated throughout long-term stationary phase (12 weeks). Acid and ammonia production was balanced so that the culture pH was maintained above pH 5.6. Strains isolated from long-term stationary-phase cultures accumulated mutations that resulted in unique exponential-phase metabolisms, with some strains expressing the PA pathway, some strains producing ammonia, and some strains expressing both in the presence of glucose. Strains expressing high levels of PA pathway activity during exponential growth were unable to survive when regrown in pure culture due to the production of excess acid. These data suggest that S. pyogenes diversifies during survival in stationary phase into distinct strains with different metabolisms and that complementary metabolism is required to control the pH in stationary-phase cultures. One of three survivor strains isolated from tonsillar discard material from patients expressed high levels of the PA pathway during exponential growth. Sequencing of multiple group A streptococcus regulators revealed two different mutations in two different strains, suggesting that random mutation occurs during survival.
机译：化脓性链球菌除引起暴发性疾病外，还可以无症状携带，并且可以在宿主中存活而不会引起疾病。长期固定相培养用于表征葡萄糖消耗后存活的培养物的代谢。通过将细胞切换至磷酸盐缓冲液或添加抗生素，可以截断葡萄糖贫乏的培养基中固定相培养物的存活，这表明存活取决于营养物质和代谢活性的存在。丙酮酸-乙酸（PA）途径（乙酸和甲酸）和氨基酸分解代谢途径（氨）的代谢产物在整个长期固定阶段（12周）积累。酸和氨的产生达到平衡，以使培养液的pH值保持在5.6以上。从长期固定相培养物中分离的菌株积累的突变导致独特的指数相代谢，有些菌株表达PA途径，有些菌株产生氨，有些菌株在葡萄糖存在下均表达。当在纯培养物中再生时，由于产生过量的酸，在指数生长过程中表达高水平PA途径活性的菌株无法生存。这些数据表明 S。化脓菌在固定相的生存过程中会分化成具有不同代谢的不同菌株，并且需要补充代谢来控制固定相培养物中的pH。从患者的扁桃体丢弃物分离出的三个幸存菌株之一在指数生长过程中表达了高水平的PA途径。多个A组链球菌调节剂的测序揭示了两种不同菌株中的两种不同突变，表明在生存期间会发生随机突变。

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