Mathematical models of membrane biophysics and microbial locomotion

描述（由申请人提供）：在此资助期间进行的研究福尔斯分为两大类（i）膜生物物理学和（ii）细菌推进。这 将与从事特定生物研究的实验室合作和/或通信开展工作。这些模型将主要用于理解和解释他们的实验观察。然而，以往的经验表明，针对特定生物系统的模型往往会导致适用于更广泛现象的一般原则。本项目的具体目标是对以下系统进行建模。1.膜动力学。我们将使用脂质倾斜模型来讨论内质网（ER）中脂滴的形成。我们认为这个自由度是必要的，以解释囊泡融合和断裂，涉及膜几何结构的拓扑变化。使用脂质倾斜的连续模型，我们将专注于芽的起始和生长及其随后的切断。我们的模型还允许我们模拟脂质在膜中的流动。这在细胞内细胞器的膜形状发生巨大变化时，例如在胞膜向板层转变时，是很重要的。这项工作将与D教授合作进行。Steigmann（UC Berkeley）. 2.细菌推进。我们将讨论新的推进机制，以前没有被建模，并为实验观察提供线索，他们的工作方式。我们的注意力将集中在（i）黄色粘球菌和相关细菌（例如黄细菌）的滑行A-运动系统，以及（ii）蓝细菌聚球藻的游动。这项工作将与D教授的实验室合作进行。Zusman（加州大学伯克利分校）和B博士。Brahamsha（Scripps）.数学建模将与J. Neu教授（加州大学伯克利分校）合作进行。

DESCRIPTION (provided by applicant): The research undertaken during the period of this grant falls into two general categories (i) membrane biophysics and (ii) bacterial propulsion. This work will be performed in collaboration and/or correspondence with experimental laboratories engaged in studies on specific organisms. The models will be primarily directed towards understanding and explaining their experimental observations. However, previous experience assures that models directed at particular biological systems frequently lead to general principles that apply to a wider range of phenomena. The specific goals of this project are to model the following systems. 1. Membrane dynamics. We will address the formation of lipid droplets from the endoplasmic reticulum (ER) using models of lipid tilt. We consider this degree of freedom essential to explain vesicle fusion and scission that involve topological changes in membrane geometry. Using continuum models of lipid tilt, we will focus on the initiation and growth of the bud and its subsequent scission. Our model also allows us to model the flow of lipid in the membrane. This is important in dramatic membrane shape changes such as that in the cubic-to-lamellar transition in intracellular organelles. This work will be carried out in collaboration with Prof. D. Steigmann (UC Berkeley). 2. Bacterial propulsion. We will address novel propulsive mechanisms that have not been previously modeled, and for which experimental observations provide clues to their modus operandi. Our attention will be directed at (i) the gliding A-motility system of Myxococcus xanthus and related bacteria (e.g. Flavobacteria), and (ii) the swimming of the cyanobacterium, Synechococcus. This work will be carried out in collaboration with the experimental laboratories of Professor D. Zusman (UC Berkeley) and Dr. B. Brahamsha (Scripps). The mathematical modeling will be carried out in collaboration with Professor J. Neu (UC Berkeley).