Identification of Fitness Determinants during Energy-Limited Growth Arrest in Pseudomonas aeruginosa.
Identification of Fitness Determinants during Energy-Limited Growth Arrest in Pseudomonas aeruginosa.
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DOI：
10.1128/mbio.01170-17
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发表时间：
2017-11-28
期刊：
影响因子：
6.4
通讯作者：
Newman DK
中科院分区：
文献类型：
--
作者：
Basta DW;Bergkessel M;Newman DK
微生物的生长停滞可以由潜水员因素触发，其中之一是电子供体或受体的稀缺性，这些基因在能量限制的生长停滞期间的适应性以及它们在不同类型的能量限制之间重叠的程度在这项研究中仍然有限地定义。在两种类型的限制下，电子供体或氧气的氧气均降低，但在没有氧气的情况下，更严重的是，我们在没有氧气的情况下（TN-Seq）。特定的活动，例如，在两种类型的能量限制期间，都需要全球调节器RPO，而在碳或氧气限制的情况下，其他全球调节器（例如DKSA和LASR）需要分别使用。在我们的筛查中检测到的突变体的突变体在不同的功能类别中暴露了不同的适应性动力学：调节基因通常早期表现出表型，而与细胞壁代谢有关的基因则在以后需要提供新的窗口。
在分子水平上，生长的细菌本质上是无处不在的，但在分子水平上，生长的细胞构成了成熟的生物膜的主要亚群，是慢性感染的生长鉴定的抗生素，并构成了对生长的生长，并构成了对生长的生长，并确定了抗生素的作用。使用tn-seq，当能量限制有机碳或氧气时，我们确定了铜绿假单胞菌的适应性所需的基因，这代表了在潜水员栖息地中为铜绿假单胞菌的生长停滞的两个常见原因现在可以指导了解在这些条件下负责这些活动的生物分子如何促进健康。
Microbial growth arrest can be triggered by diverse factors, one of which is energy limitation due to scarcity of electron donors or acceptors. Genes that govern fitness during energy-limited growth arrest and the extent to which they overlap between different types of energy limitation are poorly defined. In this study, we exploited the fact that Pseudomonas aeruginosa can remain viable over several weeks when limited for organic carbon (pyruvate) as an electron donor or oxygen as an electron acceptor. ATP values were reduced under both types of limitation, yet more severely in the absence of oxygen. Using transposon-insertion sequencing (Tn-seq), we identified fitness determinants in these two energy-limited states. Multiple genes encoding general functions like transcriptional regulation and energy generation were required for fitness during carbon or oxygen limitation, yet many specific genes, and thus specific activities, differed in their relevance between these states. For instance, the global regulator RpoS was required during both types of energy limitation, while other global regulators such as DksA and LasR were required only during carbon or oxygen limitation, respectively. Similarly, certain ribosomal and tRNA modifications were specifically required during oxygen limitation. We validated fitness defects during energy limitation using independently generated mutants of genes detected in our screen. Mutants in distinct functional categories exhibited different fitness dynamics: regulatory genes generally manifested a phenotype early, whereas genes involved in cell wall metabolism were required later. Together, these results provide a new window into how P. aeruginosa survives growth arrest. Growth-arrested bacteria are ubiquitous in nature and disease yet understudied at the molecular level. For example, growth-arrested cells constitute a major subpopulation of mature biofilms, serving as an antibiotic-tolerant reservoir in chronic infections. Identification of the genes required for survival of growth arrest (encompassing entry, maintenance, and exit) is an important first step toward understanding the physiology of bacteria in this state. Using Tn-seq, we identified and validated genes required for fitness of Pseudomonas aeruginosa when energy limited for organic carbon or oxygen, which represent two common causes of growth arrest for P. aeruginosa in diverse habitats. This unbiased, genome-wide survey is the first to reveal essential activities for a pathogen experiencing different types of energy limitation, finding both shared and divergent activities that are relevant at different survival stages. Future efforts can now be directed toward understanding how the biomolecules responsible for these activities contribute to fitness under these conditions.