Salmonella sRNAs drive the decision between active stress resistance and persister cell dormancy

细菌的持久细胞在代谢上相对不活跃，能够应对长期的环境应激，对抗生素也相对耐受。该项目旨在研究导致周围细胞形成的过程，因为更好地了解这些过程可以显著提高我们应对诸如抗生素耐药性、食源性疾病暴发和农业疾病等社会挑战的能力。此外，该项目还提供微生物学、分子生物学和计算遗传学/生物信息学方面的跨学科学生培训机会。当地高中生将通过两个不同的举措直接受益于这一项目。值得注意的是，这些努力旨在提高未被充分代表的少数族裔学生的兴趣，并提高他们在生物学和其他STEM领域的入学率。沙门氏菌在短期碳饥饿下的sRNA图谱与长期饥饿时看到的有很大的不同。同样，高度不同的sRNA图谱与初始和长期的细胞干燥有关。相反，在短时间的碳饥饿和干燥的细胞中表达的sRNA之间以及在长期的干燥和长期的碳饥饿中表达的sRNA之间的显著重叠被观察到。此外，在短期应激暴露中通常诱导的几个sRNA是通过RNA聚合酶(RNAP)sigma亚基rpos转录的启动子表达的。相反，在长期暴露期间通常诱导的许多sRNA是由替代sigma亚单位RpoE靶向的启动子表达的。综上所述，这些发现表明：在沙门氏菌中，可选择的RNAP sigma亚基选择和随后不同的sRNA组的表达驱动着在主动抗压和持久形成之间的决定。在此背景下，为该项目概述的工作意义重大，因为它将利用一系列基因操作和转录分析来表征替代的sigma亚基和特定的sRNA在驱动主动抗逆性和持久形成之间的决定中的新的、重要的角色。除了表征驱动活性抗逆性和持久形成之间的决定的分子开关之外，这项工作测试的中心模型-替代的sigma因子通过指导不同组抑制相反的sigma因子的sRNA的转录相互竞争-可能很好地构成原核生物sigma分子开关调节的一般机制，并对一系列额外的过程产生影响。因此，这项研究中进行的工作将探索一种新颖的、系统水平的全球原核转录组重新编程的调控机制，这可能会增进我们对驱动微生物应激反应的分子机制的基本知识。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Bacterial persister cells are relatively inactive metabolically, able to cope with long-term environmental stress and are relatively tolerant of antibiotics. This project aims to study the processes that lead to persister cell formation, as a better understanding of these processes could significantly improve our ability to address societal challenges such as antibiotic resistance, foodborne illness outbreaks, and agricultural diseases. In addition, this project provides interdisciplinary student training opportunities in microbiology, molecular biology, and computational genetics/bioinformatics. Local high school students will directly benefit from this project through two separate initiatives. Notably, these efforts are intended to increase underrepresented minority student interest and enrollment in biology and other STEM fields. The sRNA profile of Salmonella subjected to short term carbon starvation is highly distinct from that seen during prolonged starvation. Similarly, highly distinct sRNA profiles are associated with initial and prolonged cellular desiccation. In contrast, significant overlaps between the sRNAs expressed in cells subjected to short durations of carbon starvation and desiccation, as well as significant overlaps between the sRNAs expressed during prolonged desiccation and long-term carbon starvation have been observed. Furthermore, several of the sRNAs commonly induced during short duration stress exposures are expressed from promoters transcribed via the RNA polymerase (RNAP) sigma subunit RpoS. Conversely, many of the sRNAs commonly induced during long term exposures are expressed from promoters targeted by the alternative sigma subunit RpoE. Together, these findings suggest the following: alternative RNAP sigma subunit selection and consequent expression of distinct sets of sRNAs drive the decision between active stress resistance and persister formation in Salmonella. Against this background, the work outlined for this project is significant, as it will employ an array of genetic manipulations and transcriptomic assays to characterize new, essential roles for alternative sigma subunits and specific sRNAs in driving the decision between active stress resistance and persister formation. Beyond characterizing the molecular switch driving the decision between active stress resistance and persister formation, the central model tested by this work-alternative sigma factors compete with one another through directing the transcription of distinct sets of sRNAs that inhibit opposing sigma factors-may well constitute a general mechanism of prokaryotic sigma molecular switch regulation with implications for an array of additional processes. As such, the work performed in this study will explore a novel, systems-level regulatory mechanism for global prokaryotic transcriptome reprogramming, which might advance our basic knowledge of the molecular mechanisms driving microbial stress responses.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.