Characterizing the basic biology and mechanisms of biofilms in Vibrio cholerae

我的实验室致力于研究生物膜的基础生物学和机制，使用霍乱弧菌作为一种生物膜。 模型系统虽然这种细菌是霍乱的病原体，但我们并不寻求 研究这种病原体的毒性相反，我们利用这个完善的模型系统和遗传 我们已经开发了在生理相关背景下表征生物膜的工具。的形成 称为生物膜的复杂多细胞细菌群落对于毒性、环境 持久性，或不同微生物病原体的遗传交换。因此，了解这些机制 潜在的生物膜形成可能会发现新的方法来对抗各种临床相关的感染。 霍乱弧菌在其水生水库中在甲壳类浮游动物的几丁质壳上形成生物膜。 甲壳素生物膜在该生物体的生态学中起三个重要作用。首先，霍乱弧菌将几丁质降解成 可溶性低聚糖，在水环境中作为重要的碳源和氮源。 第二，在几丁质生物膜中生长诱导自然转化，这是水平基因的保守机制 转移，可以促进获得抗生素抗性基因和新的毒力因子。三、甲壳素 生物膜对霍乱的水传播很重要。在摄入几丁质生物膜后，V。 胆固醇必须迅速改变其代谢，从生长在几丁质上到与肠道微生物群竞争， 在其感染的宿主体内可利用的碳源。我们的模型系统提供了独特的机会， 表征细菌群落内的细胞如何利用几丁质的生物表面形成生物膜， 营养源，基因交换和传播的平台。在未来五年，我们的目标是 初始粘附几丁质的机制，自然转化过程中DNA的吸收和整合，以及 在几丁质生物膜中生长期间和在传播后的哺乳动物宿主中的代谢。 为此，我们开发了一些新的工具来解决这些问题。也就是说，我们使用 荧光标记皮利的新方法，所述皮利是最初附着于几丁质所需的表面附属物 以及自然转化过程中的DNA摄取。利用这种方法，我们可以观察到 这些皮利。这是不可能的任何其他方法，并应允许我们解决他们的作用，几丁质生物膜。 皮利是广泛保存的，我们的研究将解决这些基本和长期存在的问题 这些结构应该适用于许多细菌病原体。我们最近还改进了一种方法 用于通过自然转化的多重基因组编辑（MuGENT），其可用于解剖复杂的 基因冗余带来的生物学问题。在初步数据中，我们证明， 该工具已准备好解剖几丁质生物膜和哺乳动物宿主中霍乱弧菌的代谢。的 提出的创新方法将为关键和保守过程的研究提供一个范例（即， 粘附、生物膜形成、自然转化和代谢）。

My lab is focused on studying the basic biology and mechanisms of biofilms using Vibrio cholerae as a model system. While this bacterium is the causative agent of the diarrheal disease cholera, we do not seek to study the virulence of this pathogen. Instead, we leverage this well-established model system and the genetic tools we have developed to characterize biofilms in a physiologically relevant context. The formation of complex multicellular bacterial communities known as biofilms is critical for virulence, environmental persistence, or genetic exchange in diverse microbial pathogens. Thus, understanding the mechanisms underlying biofilm formation may uncover novel approaches to combat diverse clinically relevant infections. V. cholerae forms biofilms in its aquatic reservoir on the chitinous shells of crustacean zooplankton. Chitin biofilms play three important roles in the ecology of this organism. First, V. cholerae degrades chitin into soluble oligosaccharides, which serve as an important carbon and nitrogen source in the aquatic environment. Second, growth in chitin biofilms induces natural transformation, a conserved mechanism of horizontal gene transfer that can promote the acquisition of antibiotic resistance genes and novel virulence factors. Third, chitin biofilms are important for the waterborne transmission of cholera. Following ingestion of a chitin biofilm, V. cholerae must rapidly alter its metabolism from growth on chitin to competing with the intestinal microbiota for the carbon sources available within its infected host. Our model system provides a unique opportunity to characterize how cells within a bacterial community utilize the biotic surface of chitin for biofilm formation, as a nutrient source, a platform for genetic exchange, and transmission. In the next five years, we aim to define the mechanisms of initial adherence to chitin, DNA uptake and integration during natural transformation, and metabolism during growth in chitin biofilms and in the mammalian host following transmission. To that end, we have generated a number of novel tools to address these questions. Namely, we use a novel method to fluorescently label pili, which are surface appendages required for initial attachment to chitin and for DNA uptake during natural transformation. Using this method, we can observe the dynamic nature of these pili. This is not possible by any other approach and should allow us to address their role in chitin biofilms. Pili are broadly conserved, and our studies will address fundamental and long-standing questions about these structures that should be applicable to many bacterial pathogens. We have also recently improved a method for multiplex genome editing by natural transformation (MuGENT), which can be used to dissect complex biological questions where genetic redundancy poses an issue. In preliminary data we demonstrate that this tool is well poised to dissect the metabolism of V. cholerae in chitin biofilms and in the mammalian host. The innovative approaches proposed will provide a paradigm for the study of critical and conserved processes (i.e. adherence, biofilm formation, natural transformation, and metabolism) in diverse microbial species.