Bacterial cell wall synthesis, shape and septation

项目摘要 细菌细胞形状具有基本的和医学上的重要性，通过以下方式有助于存活和毒力： 影响营养吸收、细胞与表面的附着、运动、分化和对捕食的抗性，或 宿主免疫此外，形态学研究正在阐明以前未被认识到的相互作用 在驱动细菌生长的各种生化事件中。简而言之，形态学在 细菌生理学、生态学和发病机理，并作为细胞生物学的窗口。大多数细菌 通过制造肽聚糖细胞壁来确定它们的形状，而干扰这种结构是其中之一。 最重要的抗菌治疗靶点。尽管经过几十年的努力， 了解肽聚糖合成如何与相关代谢途径整合。一个积分 点是载体分子十一异戊二烯磷酸（Und-P），它有助于合成肽聚糖和其他 低聚糖。显然，联合国发展伙伴关系及其衍生物构成了一个至关重要的联系， 详细描述了其特征，以帮助对抗日益增加的抗生素耐药性。为此，我们提出以下建议： 目标。目的1]确定Und-P管理如何改变细菌生理学和生物化学。UND-P和 它的同系物在所有细胞中运输许多化合物和聚合物穿过细胞质膜。 生物界，包括古生菌和真核生物。因为最终产品是由多种 路线，载体必须在几个生化途径之间共享，但如何实现这一点是未知的。 未知然而，这是至关重要的-如果Und-P被隔离在一个途径中，那么肽聚糖的可用性就更少了。 合成和细胞生长不良或死亡。我们将开发工具来监测活细胞中Und-P的含量 并将决定对Und-P的竞争如何影响细菌生长和每个途径的运作。 目的2]鉴定和表征新的和鲜为人知的Und-P利用途径。虽然有几个Und-P- 依赖性途径是已知的，但有许多途径几乎没有可用的信息，毫无疑问， 还有一些我们一无所知我们将描述这些途径预计存在于大肠杆菌 并将启动基因筛选来寻找其他人。目的3]鉴定和表征细胞形状突变体。 历史上，大多数形态突变体都是在研究其他东西时发现的。在这里，我们将 继续使用流式细胞术分离这些突变体，以确定影响细菌形状的新机制。 我们还将更全面地描述我们已经掌握的突变体。总之，这些工具和 这些方法将使我们能够更快、更深入地调查围绕Und-P的谜团 利用及其与基本代谢途径的相互作用。此外，这项工作将创造一个良好的- 开发的细菌模型将为许多其他生物体的类似研究提供信息并加强其研究。

PROJECT SUMMARY Bacterial cell shape is of fundamental and medical importance, contributing to survival and virulence by influencing nutrient uptake, cell-to-surface attachment, motility, differentiation, and resistance to predation or host immunity. Furthermore, morphological studies are illuminating previously unrecognized interactions among diverse biochemical events that drive bacterial growth. In short, morphology plays crucial roles in bacterial physiology, ecology and pathogenesis, and serves as a window into cell biology. Most bacteria determine their shapes by making a peptidoglycan cell wall, and interfering with this structure is one of the most important targets for anti-bacterial therapy. Despite decades of work, there remain large gaps in understanding how peptidoglycan synthesis is integrated with related metabolic pathways. One integration point is the carrier molecule undecaprenyl-phosphate (Und-P), which helps synthesize peptidoglycan and other oligosaccharides. It has become clear that Und-P and its derivatives form a vital nexus that must be characterized in detail to help combat increasing antibiotic resistance. To this end we propose the following Aims. Aim 1] Determine how Und-P management alters bacterial physiology and biochemistry. Und-P and its homologues transport numerous compounds and polymers across the cytoplasmic membranes of cells in all biological kingdoms, including archaea and eukaryotes. Because the end-products are synthesized by diverse routes, the carrier must be shared among several biochemical pathways, but how this is accomplished is unknown. It is, however, vital – if Und-P is sequestered in one pathway, less is available for peptidoglycan synthesis and cells grow poorly or die. We will develop tools to monitor the amounts of Und-P in living cells and will determine how competition for Und-P affects bacterial growth and the operation of each pathway. Aim 2] Identify and characterize new and little-known Und-P-utilizing pathways. Although several Und-P- dependent pathways are known, there are many for which little information is available and, undoubtedly, others we know nothing about at all. We will characterize those pathways projected to exist in Escherichia coli and will initiate genetic screens to look for others. Aim 3] Identify and characterize cell shape mutants. Historically, most morphological mutants were discovered while studying something else. Here, we will continue to use flow cytometry to isolate such mutants, to identify new mechanisms that affect bacterial shape. We will also characterize more fully the mutants we already have in hand. In summary, these tools and approaches will enable us to investigate, faster and in greater depth, the mysteries surrounding Und-P utilization and its interactions with basic metabolic pathways. In addition, the work will create a well- developed bacterial model that will inform and enhance similar investigations in many other organisms.