McClary Jill S, Boehm Alexandria B
Civil and Environmental Engineering, Stanford University, Stanford, CA, United States.
Front Microbiol. 2018 Feb 23;9:249. doi: 10.3389/fmicb.2018.00249. eCollection 2018.
The transcriptional response of strain Newman to sunlight exposure was investigated under both oxic and anoxic conditions using RNA sequencing to gain insight into potential mechanisms of inactivation. is a pathogenic bacterium detected at recreational beaches which can cause gastrointestinal illness and skin infections, and is of increasing public health concern. To investigate the photostress response in oligotrophic seawater, cultures were suspended in seawater and exposed to full spectrum simulated sunlight. Experiments were performed under oxic or anoxic conditions to gain insight into the effects of oxygen-mediated and non-oxygen-mediated inactivation mechanisms. Transcript abundance was measured after 6 h of sunlight exposure using RNA sequencing and was compared to transcript abundance in paired dark control experiments. Culturable decayed following biphasic inactivation kinetics with initial decay rate constants of 0.1 and 0.03 m kJ in oxic and anoxic conditions, respectively. RNA sequencing revealed that 71 genes had different transcript abundance in the oxic sunlit experiments compared to dark controls, and 18 genes had different transcript abundance in the anoxic sunlit experiments compared to dark controls. The majority of genes showed reduced transcript abundance in the sunlit experiments under both conditions. Three genes (, and ) were found to have the same transcriptional response to sunlight between both oxic and anoxic conditions. In the oxic condition, transcripts associated with porphyrin metabolism, nitrate metabolism, and membrane transport functions were increased in abundance during sunlight exposure. Results suggest that responds differently to oxygen-dependent and oxygen-independent photostress, and that endogenous photosensitizers play an important role during oxygen-dependent indirect photoinactivation.
使用RNA测序技术，在有氧和无氧条件下研究了纽曼菌株对阳光照射的转录反应，以深入了解其潜在的失活机制。纽曼菌株是在休闲海滩检测到的一种致病细菌，可导致胃肠道疾病和皮肤感染，日益引起公众健康关注。为了研究贫营养海水中该菌株的光应激反应，将其培养物悬浮于海水中并暴露于全光谱模拟阳光下。在有氧或无氧条件下进行实验，以深入了解氧介导和非氧介导的失活机制的影响。在阳光照射6小时后，使用RNA测序测量转录本丰度，并将其与配对的黑暗对照实验中的转录本丰度进行比较。可培养的纽曼菌株遵循双相失活动力学衰减，在有氧和无氧条件下的初始衰减速率常数分别为0.1和0.03 m kJ。RNA测序显示，与黑暗对照相比，在有氧阳光照射实验中有71个基因的转录本丰度不同，在无氧阳光照射实验中有18个基因的转录本丰度不同。在两种条件下的阳光照射实验中，大多数基因的转录本丰度都降低了。发现三个基因（具体基因未给出）在有氧和无氧条件下对阳光具有相同的转录反应。在有氧条件下，与卟啉代谢、硝酸盐代谢和膜转运功能相关的转录本在阳光照射期间丰度增加。结果表明，纽曼菌株对依赖氧和不依赖氧的光应激反应不同，并且内源性光敏剂在依赖氧的间接光失活过程中起重要作用。
