Genetic Analysis of Myxococcus Xanthus Sensory Transduction

智力价值在自然环境中，微生物通常生活在与表面相关的称为生物膜的群落中。有些生物膜是有害的。生物膜损害每年造成的损失估计超过10亿美元，部分原因是人类健康的发病率和死亡率，部分原因是表面的损害和生物污垢。了解生物膜中细胞之间的通讯渠道可能会导致抑制生物膜形成的机制的发展。一种研究生物膜形成的模式生物是黄色粘球菌，它诱导生物膜形成是导致子实体发育的独特生命周期的一部分。子实体是一种含有休眠孢子的无性生殖结构，由成千上万的细胞定向运动形成。Dif化学感觉通路响应环境和其他细胞提供的信号，调节黄花生物膜的形成和子实体的发育。两个这样的信号是营养限制，启动发育的一般刺激，以及控制定向细胞运动的特定脂类的存在。该通路包含一个用于感知信号的受体，两个用于控制行为输出的磷中继系统，以及其他尚未识别的组件。这个项目试图确定该通路对改变细胞行为的线索做出反应的机制。遗传方法将被用来识别与同化线索有关的基因产物。激光共聚焦扫描显微镜和微电影照相术将被用来通过比较野生型细胞和缺乏Dif途径组件的突变体的行为来检查这些线索如何影响细胞的行为。额外的检测将用于确定突变体是否在信号产生、基因表达或定向运动方面存在缺陷。这些实验有望揭示这种生物是如何形成生物膜的，并利用生物膜来指导子实体的形成和孢子的产生。广泛的影响：该项目将成为训练本科生和研究生进行严格的批判性思维、实验设计和执行的场所。这一机会将提供给目前在科学职业生涯中代表性不足的群体，特别是少数族裔、残疾人和女性学生。听障学生可选择签名者。学生们还将通过《科学诚信？》这本书学习科学中的伦理问题。作者Frank Macrina补充了阅读材料和其他来源的案例研究。目标是在实现多样性和机会平等的同时培养下一代科学家。

Intellectual MeritIn natural settings microbes often live in surface-associated communities called biofilms. Some biofilms are harmful. Biofilm damage results in estimated annual costs in excess of $1 billion due in part to morbidity and mortality of human health and in part to damage and biofouling of surfaces. Understanding the channels of communication between cells in a biofilm could lead to the development of mechanisms that suppress biofilm formation. A model organism for examining biofilm formation is Myxococcus xanthus, which induces biofilm formation as part of a unique life cycle leading to fruiting body development. The fruiting body is an asexual reproductive structure that contains dormant spores and that is formed by directed movement of tens of thousands of cells. The Dif chemosensory pathway regulates biofilm formation and fruiting body development in M. xanthus in response to cues provided by the environment and other cells. Two such cues are nutrient limitation, a general stimulus for the initiation of development, and the presence of specific lipids, which control directed cell movement. The pathway contains a receptor for perceiving the signals, two component phosphorelay systems for controlling the behavioral output, and other as yet unidentified components. This project seeks to determine the mechanisms by which the pathway responds to cues to change the behavior of the cells. Genetic approaches will be used to identify gene products involved in assimilating the cues. Confocal laser scanning microscopy and microcinematography will be used to examine how the cues impact the behavior of the cells by comparing the behavior of wild type cells with mutants lacking a component of the Dif pathway. Additional assays will be used to determine whether the mutants are defective in signal production, gene expression, or directed movement. Together these experiments are expected to reveal how this organism makes a biofilm and uses the biofilm to direct the formation of a fruiting body and the production of spores.Broader Impacts:The project will serve as a venue for training undergraduate and graduate students in the rigors of critical thinking, and experimental design and execution. This opportunity will be available to groups currently underrepresented in science careers notably minority, disabled, and female students. A signer is available for the hearing impaired students. Students will also learn of ethical issues in science using the book ?Scientific Integrity? by Frank Macrina supplemented with reading materials and case studies from other sources. The goal is to train the next generation of scientists while achieving diversity and equal opportunity.