Developing novel models to understand threats from Vibrio pathogens for safeguarding aquatic food supply under future climates

开发新模型来了解弧菌病原体的威胁，以保障未来气候下的水产食品供应

• 批准号: NE/X010333/1
• 负责人: Charles Tyler
• 金额: $ 10.26万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Research Grant
• 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%2FX010333%2F1
• 关键词: Developing; novel; models; understand; threats

Climate change, leading to ocean warming, is affecting the frequency, intensity and duration of extreme weather events affecting nearshore ecosystems that will make our UK coastal shellfisheries more vulnerable to new and emerging microbial diseases, and with potentially greater associated human health concerns. When bacteria encounter extreme or unfavourable environmental conditions they enter a state of dormancy to protect themselves, however, they can re-awaken when favourable environmental conditions return. For bacterial pathogens these re-emergent blooms can be hazardous to the environment and in some cases to human health. A major problem in the prevention of bacterial diseases is that dormant cells are not detectable by routine tests making them difficult to study. In this project, we will exploit new approaches to understand the ways (mechanisms) by which dormant bacterial Vibrio cells (our study organism) emerge as active disease-causing pathogens in the environment to provide a springboard for future projects for predicting and preventing Vibrio disease establishment in wild shellfisheries and farmed shellfish, and the protection of human health.Vibriosis is a disease responsible for numerous mass mortality events in managed and wild shellfisheries, and globally Vibrio pathogens are the leading causes of seafood related gastroenteritis in humans. In our coastal waters, sediment and shellfish, Vibrio parahaemolyticus is found during the summer months but is not detected in the winter. It had been assumed that these bacteria die due to the cold-water temperatures, however, we know now that a small proportion enter dormancy in order to survive cooler (winter) conditions. When summer conditions return and, nutrient levels and sea temperatures increase these dormant cells reawaken, growing into bacterial populations that can infect shellfish and cause adverse human health impacts. In this project, we will first detect and quantify Vibrio in its various functional states in relation to environmental abiotic factors in water, sediment, and shellfish from a coastal site in Dorset, England. The cell sorting and staining methods we will apply, will allow us to separate dormant Vibrio cell populations from those that are metabolically active and those that are non-viable. We will then assess the ability to resuscitate the dormant cells collected from the environmental samples through manipulating the salt and temperature to simulate summer conditions and with the addition of sodium lactate (we have shown that lactate can resuscitate Vibrio dormant cells for our laboratory induced dormant cells). We will also test the virulence potential of the resuscitated Vibrio cells derived from our environmental samples through their injection to an established moth larvae disease model. Finally, we will develop analytical protocols (using mass spectrophotometry methods) to determine the fate of lactate in environmental dormant cells and identify metabolism mechanisms as the dormant cells switch to the actively growing cell population. Collectively these studies will be a major step forward in establishing the factors that allow Vibrio cells to emerge from dormancy and establish as a growing population under favourable climate conditions to cause disease. Improving our ability to predict when Vibrio bacterial populations are established will help prevent disease reinfections and avoidance of seasonal epidemics through adoption of mitigation strategies such as depuration of the shellfish, and/or early and/or selective harvesting.

气候变化导致海洋变暖，正在影响影响近岸生态系统的极端天气事件的频率、强度和持续时间，这将使英国沿海贝类渔业更容易受到新出现的微生物疾病的影响，并可能带来更大的相关人类健康问题。当细菌遇到极端或不利的环境条件时，它们会进入休眠状态以保护自己，但当有利的环境条件恢复时，它们可以重新苏醒。对于细菌病原体来说，这些重新出现的水华可能对环境有害，在某些情况下还会对人类健康造成危害。预防细菌性疾病的一个主要问题是常规测试无法检测到休眠细胞，这使得它们难以研究。在这个项目中，我们将利用新方法来了解休眠细菌弧菌细胞（我们的研究生物体）在环境中作为活跃的致病病原体出现的方式（机制），为未来预测和预防弧菌疾病的项目提供跳板野生贝类和养殖贝类的建立，以及保护人类健康。弧菌病是一种导致管理和野生贝类渔业中许多大规模死亡事件的疾病，在全球范围内，弧菌病原体是海鲜相关疾病的主要原因人类胃肠炎。在我们的沿海水域、沉积物和贝类中，夏季会发现副溶血弧菌，但在冬季则不会检测到。人们曾认为这些细菌会因冷水温度而死亡，然而，我们现在知道一小部分细菌进入休眠状态以在较冷（冬季）的条件下生存。当夏季条件恢复时，营养水平和海水温度升高，这些休眠细胞重新苏醒，生长成细菌群，可以感染贝类并对人类健康造成不利影响。在这个项目中，我们将首先检测和量化与英格兰多塞特郡沿海地区的水、沉积物和贝类中的环境非生物因素相关的各种功能状态的弧菌。我们将应用的细胞分选和染色方法将使我们能够将休眠的弧菌细胞群与代谢活跃的细胞群和非存活的细胞群分开。然后，我们将评估通过操纵盐和温度来模拟夏季条件并添加乳酸钠来复苏从环境样本中收集的休眠细胞的能力（我们已经证明，乳酸可以复苏我们实验室诱导的休眠细胞的弧菌休眠细胞） ）。我们还将通过将来自环境样本的复苏弧菌细胞注射到已建立的蛾幼虫疾病模型中来测试其毒力潜力。最后，我们将开发分析方案（使用质谱法）来确定环境休眠细胞中乳酸的命运，并确定休眠细胞切换到活跃生长的细胞群时的代谢机制。总的来说，这些研究将是在确定使弧菌细胞从休眠状态中苏醒并在有利的气候条件下形成不断增长的种群以引起疾病的因素方面迈出的重要一步。提高我们预测弧菌细菌种群何时形成的能力，将有助于通过采取缓解策略（例如贝类净化和/或早期和/或选择性收获）来防止疾病再次感染和避免季节性流行病。