Now you see them, now you don't - tracking hidden dormant bacteria in the environment

时而可见，时而看不见——追踪环境中隐藏的休眠细菌

• 批准号: NE/X018032/1
• 负责人: Sariqa Wagley
• 金额: $ 92.37万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX018032%2F1
• 关键词: Now; see; them; now; don

When you are in a deep sleep at night what wakes you up? Is it the sound of an alarm or the birds tweeting? Is it the smell of toast or coffee that stirs you awake? Do you wake up because your too hot or too cold? Or like me a tiny human wakes up and gets your attention. My research is about how bacteria enter a 'sleep-like' or 'hibernation-like' behaviour to ensure their survival in their environment and what cues they use to 'wake up' from this state of hibernation. Bacteria have clever ways to ensure they survive during periods of stress in their environment. These stresses may be a change in temperature, a lack of nutrients or it may come from antibiotic exposure or chlorination treatment. One-way bacteria survive the stress is by entering into a reversible state of dormancy. These dormant cells utilise nutrients at a reduced rate and change in size and shape to better protect themselves from unfavourable conditions. Furthermore, dormant cells are not detectable by routine tests making them difficult to study. They can stay in this 'sleep like' state until favourable conditions in the surrounding environment return, where they 'reawaken' and reproduce to cause bacterial blooms that are hazardous to the environment and in some cases human health. Scientists still do not know how bacteria are able to 'wake up' from this state of dormancy or what cues they use to change from a dormant state into an active growing population of cells.I will use Vibrio species found in the marine and estuarine environment to study bacterial dormancy. Vibrio species thrive in low salinity and warm temperatures and only appear in the environment during the warmer months. Vibrio bacteria are not detected in the winter, and it is assumed that the bacteria die due to the cold temperatures. However, a small proportion of the cells enter the dormant state to survive the winter conditions. When summer returns, nutrient levels and sea temperatures increase, and dormant Vibrio cells 'reawaken' and grow into bacterial populations. Recently, using advanced flow cytometry techniques, I was able to isolate Vibrio cells in the dormant phase from the environment, and wake them up into an active detectable population again. Using this ability to identify and manipulate dormant cells will for the first time, allow me to explore new conceptual territory in the field of bacterial dormancy.During this fellowship, I will collaborate with government agencies such as Cefas (UK) and Plant & Food Research Institute (New Zealand), seafood industry (Lyons Seafood), and international institutes (ICDDR,B, Institute of Marine Research (Norway), IZSUM (Italy), University of Barcelona, University of Alaska Fairbanks and George Mason University (USA)) to obtain environmental samples across the globe from areas where Vibrio species are abundant in the summer and thus likely to contain bacterial dormant cells during cooler months. I will uncover the geographical spread of dormant cells in the environment and whether they are present in specific niches, (e.g., sediment, water column, shellfish, oyster gut). I will look to see how dormant cells respond to changes in their environment, and identify the mechanistic processes that aid resuscitation of these dormant cells and allow them to re-emerge as a growing population. My research programme will lead to finding and developing new diagnostic tests to identify the presence of dormant bacteria early in the environment that will mitigate risks against emerging diseases from Vibrio bacteria worldwide.

当你晚上沉睡时，是什么把你叫醒的？是警报声还是鸟儿的鸣叫声？是吐司的味道还是咖啡的味道把你吵醒了？你醒来是因为你太热还是太冷？或者像我一样，一个小小的人类醒来，引起你的注意。我的研究是关于细菌如何进入“类似睡眠”或“类似冬眠”的行为，以确保它们在环境中生存，以及它们使用什么线索从这种冬眠状态中“醒来”。细菌有巧妙的方法来确保它们在环境中的压力时期存活下来。这些压力可能是温度的变化、营养物质的缺乏，也可能是来自抗生素暴露或氯化处理。细菌在压力下生存的单向途径是进入可逆的休眠状态。这些休眠的细胞利用营养的速度降低，大小和形状发生变化，以更好地保护自己免受不利条件的影响。此外，常规测试无法检测到休眠细胞，这使得对它们的研究变得困难。它们可以保持这种像睡觉一样的状态，直到周围环境的有利条件回来，在那里它们重新唤醒并繁殖，导致细菌大量繁殖，对环境和某些情况下的人类健康造成危害。科学家们仍然不知道细菌是如何从这种休眠状态“唤醒”的，也不知道它们使用什么信号从休眠状态转变为活跃的细胞种群。我将使用在海洋和河口环境中发现的弧菌来研究细菌休眠。弧菌物种在低盐度和温暖的温度下茁壮成长，只在温暖的月份出现在环境中。在冬天检测不到弧菌细菌，并假设细菌死于寒冷的温度。然而，一小部分细胞进入休眠状态以在冬季条件下生存。当夏天回来时，营养水平和海洋温度上升，休眠的弧菌细胞‘重新苏醒’并成长为细菌种群。最近，使用先进的流式细胞仪技术，我能够将处于休眠阶段的弧菌细胞从环境中分离出来，并将它们唤醒为活跃的、可检测到的种群。利用这种能力来识别和操纵休眠细胞，将使我第一次能够探索细菌休眠领域的新概念领域。在此期间，我将与下列政府机构合作：CEFAS(英国)和植物与食品研究所(新西兰)、海鲜产业(里昂海鲜)和国际研究所(ICDDR，B、海洋研究所(挪威)、IZSUM(意大利)、巴塞罗那大学、阿拉斯加大学费尔班克斯分校和乔治梅森大学(美国))，以获取全球各地夏季弧菌物种丰富、因此可能在凉爽月份含有细菌休眠细胞的地区的环境样本。我将揭示休眠细胞在环境中的地理分布，以及它们是否存在于特定的生态位中(例如，沉积物、水柱、贝类、牡蛎肠道)。我将观察休眠细胞如何应对环境的变化，并确定帮助这些休眠细胞复苏并允许它们作为不断增长的种群重新出现的机械过程。我的研究计划将导致发现和开发新的诊断测试，以在环境中及早识别休眠细菌的存在，这将减少世界各地弧菌引起的新疾病的风险。