Interplay Between Prokaryotic Organelle Dynamics and Cell Physiology

描述（由申请人提供）：在过去几十年中，细菌细胞的结构和组织复杂性变得越来越明显。它现在是公认的细胞极性，功能膜微区，和离散的细胞质蛋白和膜结合区室是普遍存在于不同的细菌物种。此外，这些结构的破坏会损害细菌的生理学和与毒力相关的行为。然而，在许多情况下，对细菌组织的机制以及这种组织如何影响细胞生理学的理解并不完全。 该提案描述了使用紫色非硫细菌（PNSB）Rhodopyramidpalustris，作为一种模式生物，以评估细菌细胞器的发育和定位如何影响（和受影响）细胞生理学。PNSB在光养条件下生长时形成膜状光合细胞器（胞质膜，ICM）。初步数据表明，自然自发荧光的光系统色素细菌叶绿素可以利用活细胞中，很容易地监测ICM相关的光系统的分布模式。这些系统在R中是离散局部化的。palustris与许多其他模型PNSB相反，其中ICM存在于整个细胞中。我们建议利用PNBS物种之间ICM结构和定位的差异来评估ICM结构，光系统组织，ICM遗传和细胞生长模式之间可能存在的相关性。我们还将评估ICM动力学对R代谢稳健性的重要性。沼泽 该建议的具体目标是：（i）确定R的时间和空间定位。palustris光系统及其对代谢稳态的贡献，以及（ii）确定调节R. palustris光系统定位和表征光系统定位的生理作用。将采取多学科的方法来解决这些目标，将包括细胞生物学（荧光显微镜，电子显微镜），遗传学（有针对性的和随机诱变），和化学（使用非放射性同位素的代谢通量分析）。总的来说，这些实验将促进对细菌区室化如何有助于代谢稳健性和影响细胞生理学的理解。

DESCRIPTION (provided by applicant): The structural and organizational complexity of bacterial cells has become increasingly apparent over the last several decades. It is now well established that cell polarity, functional membrane microdomains, and discrete cytoplasmic protein- and membrane-bound compartments are prevalent in diverse bacterial species. Furthermore, disruption of these architectures can impair bacterial physiology and virulence-related behaviors. In many instances, however, there is an incomplete understanding of mechanisms underlying bacterial organization and how such organization affects cell physiology. This proposal describes the use of the purple nonsulfur bacterium (PNSB) Rhodopseudomonas palustris, as a model organism to evaluate how bacterial organelle development and localization affect (and are affected by) cell physiology. PNSB develop a membranous photosynthetic organelle (intracytoplasmic membrane, ICM) when grown under phototrophic conditions. Preliminary data demonstrate that natural autofluorescence of the photosystem pigment bacteriochlorophyll can be utilized in live cells to easily monitor the distribution patterns of ICM-associated photosystems. These systems are discretely localized in R. palustris in contrast to many other model PNSB in which ICM is present throughout the cell. We propose to take advantage of the differences in ICM structure and localization between PNBS species to evaluate correlations that may exist between ICM structure, photosystem organization, ICM inheritance, and modes of cell growth. We will also evaluate the importance of ICM dynamics for metabolic robustness in R. palustris. The specific aims of this proposal are to: (i) determine the temporal and spatial localization of R. palustris photosystems and their contribution to metabolic homeostasis, and (ii) identify genetic factors regulating R. palustris photosystem localization and characterize the physiological role of photosystem localization. A multidisciplinary approach will be taken to address these aims and will include cell biology (fluorescence light microscopy, electron microscopy), genetics (targeted and random mutagenesis), and chemistry (metabolic flux analysis using non-radioactive isotopes). Overall, these experiments will promote the understanding of how bacterial compartmentalization contributes to metabolic robustness and impacts cell physiology.