Interaction between Vibrio cholerae and Dictylostelium discoideum

霍乱弧菌和盘基菌之间的相互作用

• 批准号: 7658402
• 负责人: ARTURO DE LOZANNE
• 金额: $ 22.44万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-05 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7658402
• 关键词: Acanthamoeba; Amoeba genus; Animal Model; Bacteria; Biochemical; Cells; Cellular biology; Cholera; Cholera Toxin; Coculture Techniques; Development; Dictyostelium discoideum; Disease; Ecology; Ecosystem; Electrolytes; Environment; Epidemic; Food; Gene Expression; Genes; Genetic; Genetic Screening; Growth; Human; In Vitro; Incidence; Laboratories; Lead; Lethal Dose 50; Life; Marines; Measures; Methods; Modeling; Morbidity - disease rate; Nature; Nutrient; Organism; Phagocytosis; Population Sizes; Predatory Behavior; Production; Reagent; Recording of previous events; Resistance; Role; Small Intestines; Soil; Source; System; Techniques; Testing; Toxin; Vibrio; Vibrio cholerae; Vibrio cholerae O1; Virulence; Virulence Factors; Water; feeding; in vivo; killings; mortality; mouse model; mutant; pandemic disease; pathogen; prevent; public health relevance; resistance mechanism; response; tool

DESCRIPTION (provided by applicant): Vibrio species are predominantly aquatic bacteria. While many of them are non-pathogenic, some vibrios are associated with severe disease in humans. Vibrio cholerae, in particular, has a long history of causing epidemic and pandemic cholera. Cholera results from colonization of the small intestine by V. cholerae, where it produces a potent toxin that results in massive water loss and electrolyte imbalance. In nature, V. cholerae may be found free-living, but its survival appears to be favored by specific associations with other organisms. Some of the genes required for V. cholerae to form these associations and persist in its aquatic ecosystem are also involved in promoting disease in humans. In vitro studies have suggested that protozoans may both use V. cholerae as a food source and promote V. cholerae survival, but the nature of these interactions is not well understood. Our studies will focus on the relationship between V. cholerae and the model protozoan amoeba Dictyostelium discoideum, and our laboratories have combined expertise in these two organisms. Our hypothesis is that V. cholerae is subject to predation by amoebae in the environment and that production of virulence factors such as cholera toxin helps protect V. cholerae from predation and enhances its survival. Further, we propose that D. discoideum can be used as a model for interaction of V. cholerae with amoebae. We will use genetic, biochemical, and cellular biology approaches to dissect the relationship between D. discoideum and V. cholerae. Analysis of mutants and genetic screens will be used to identify the V. cholerae genes required for survival and persistence in the presence of D. discoideum, and we will use cellular biology techniques to begin to elucidate the interactions between D. discoideum and V. cholerae. The specific aims are to (i) identify V. cholerae genes involved in resistance to predation by amoebae, (ii) determine the mechanism of survival of V. cholerae within D. discoideum, and (iii) determine whether V. cholerae grown in the presence of the amoeba are infectious or hypervirulent. Understanding this predator/prey relationship will not only provide basic information about V. cholerae in the environment, but also may provide clues to methods for better controlling the environmental sources of V. cholerae and thereby help prevent epidemics of cholera. PUBLIC HEALTH RELEVANCE: Vibrio cholerae is a major cause of morbidity and mortality worldwide. This bacterium has a reservoir in nature and periodically re-emerges to cause epidemics and pandemics of cholera. In order to persist in the wild, V. cholerae must be able to resist predation by amoebae. The proposed studies to determine the mechanisms of resistance to predation will lead to a better understanding of the ecology of V. cholerae. This may allow the development of strategies to control the source of epidemic V. cholerae.

描述（由申请方提供）：弧菌属主要是水生细菌。虽然它们中的许多是非致病性的，但一些弧菌与人类的严重疾病有关。特别是霍乱弧菌，具有引起流行性和大流行性霍乱的悠久历史。霍乱是由霍乱弧菌在小肠的定植引起的，它在小肠中产生一种强效毒素，导致大量水分流失和电解质失衡。在自然界中，霍乱弧菌可能是自由生活的，但它的生存似乎是由与其他生物体的特定协会所支持的。霍乱弧菌形成这些关联并在其水生生态系统中持续存在所需的一些基因也参与促进人类疾病。体外研究表明，原生动物可以使用霍乱弧菌作为食物来源，并促进霍乱弧菌的生存，但这些相互作用的性质还不清楚。我们的研究将集中在霍乱弧菌和模式原生动物阿米巴Dictyosteelium discoideum之间的关系，我们的实验室结合了这两种生物的专业知识。我们的假设是，霍乱弧菌在环境中易受阿米巴原虫的捕食，而霍乱毒素等毒力因子的产生有助于保护霍乱弧菌免受捕食，并提高其存活率。进一步，我们提出D.盘状芽孢杆菌可用作霍乱弧菌与阿米巴相互作用的模型。我们将使用遗传学、生物化学和细胞生物学的方法来剖析D. discoideum和V. cholesterol。突变体分析和遗传筛选将用于鉴定在D. discoideum之间的相互作用，我们将利用细胞生物学技术开始阐明D. discoideum和V. cholesterol。具体的目的是（i）鉴定参与抵抗阿米巴捕食的霍乱弧菌基因，（ii）确定霍乱弧菌在D.盘状弧菌，和（iii）确定在变形虫存在下生长的霍乱弧菌是否具有感染性或高毒力。了解这种捕食者/猎物关系不仅可以提供环境中霍乱弧菌的基本信息，还可以为更好地控制霍乱弧菌的环境来源提供线索，从而有助于预防霍乱的流行。公共卫生相关性：霍乱弧菌是世界范围内发病率和死亡率的主要原因。这种细菌在自然界中有一个水库，并定期重新出现，造成流行病和霍乱大流行。为了在野外生存，霍乱弧菌必须能够抵抗变形虫的捕食。对霍乱弧菌抗捕食机制的研究将有助于更好地了解霍乱弧菌的生态学。这可能有助于制定控制流行性霍乱弧菌来源的策略。