Microbial death is extremely common in nature, yet the ecological role of dead bacteria is unclear. Dead cells are assumed to provide nutrients to surrounding microbes, but may also affect them in other ways. We found adding lysate prepared from dead bacteria to cultures of E. coli in nutrient-rich conditions suppressed their final population density. This is in stark contrast with the notion that the primary role of dead cells is nutritional, although we also observed this type of effect when we added dead bacteria to cultures that were not supplied with other nutrients. We only observed the growth-suppressive effect of dead bacteria after they had undergone significant lysis, suggesting a key role for cellular contents released during lysis. Transcriptomic analysis revealed changes in gene expression in response to dead cells in growing populations, particularly in genes involved in motility. This was supported by experiments with genetic knockouts and copy-number manipulation. Because lysis is commonplace in natural and clinical settings, the growth-suppressive effect of dead cells we describe here may be a widespread and previously unrecognized constraint on bacterial population growth.

中文翻译：

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根据当地的非生物条件，暴露于裂解细菌会促进或抑制附近活细菌的生长

微生物死亡在自然界中极为普遍，但死亡细菌的生态作用尚不清楚。死细胞被假定为周围的微生物提供营养，但也可能以其他方式影响它们。我们发现，在营养丰富的条件下，将死细菌制备的裂解物添加到大肠杆菌培养物中会抑制其最终种群密度。这与死细胞的主要作用是营养这一观念形成了鲜明的对比，尽管当我们向未提供其他营养素的培养物中添加死菌时，我们也观察到了这种作用。我们只观察到死亡细菌经过显着裂解后的生长抑制作用，这表明裂解过程中释放的细胞内容物具有关键作用。转录组学分析显示，在不断增长的人群中，特别是在涉及运动性的基因中，响应死细胞的基因表达发生了变化。通过基因敲除和拷贝数操纵的实验证明了这一点。因为在自然和临床环境中裂解是司空见惯的，所以我们在此描述的死细胞的生长抑制作用可能是细菌种群增长的广泛且以前未被认识的限制。