Factors Determining the Death Rate of Starved E.coli Cells 公开

Zhang, Ace (2015)

Permanent URL: https://etd.library.emory.edu/concern/etds/1c18dg505?locale=zh
Published

Abstract

In nature, most bacteria survive in non-proliferating state due to the limitation of their access to nutrients. In such state, it has long been recognized that bacteria will progressively lose their viability. The factors determining the death rate of bacteria under starvation condition have been of great interest to scientists. Many of these factors have been very well studied on the molecular level, including the oxidative stress and the anaerobic respiration. In this research, we propose that the ongoing DNA replication in stationary phase is another factor that leads to bacteria death. We used two different methods in this study to compare the viability of cells with ongoing DNA replication and that of cells without such process. We took advantage of a temperature sensitive strain which is not able to initiate DNA replication at 43 °C but can finish ongoing replication at this temperature. Also we used the antibiotic rifampicin to achieve the same purpose. Our result shows that cells without open DNA forks do have extended lifespan under starvation condition. Moreover, we also compared the viability of rifampicin treated wild type cells with RpoS deleted cells. RpoS, a master regulator of stress response, is proved to be necessary in our research for cells to maintain the viability. We expect that the findings provide a new insight into underlying mechanisms of senescence and longevity for bacteria and other organisms.

Table of Contents

Abstract...2

Introduction...3

Result...6

Discussion...9

Methods...10

References...13

Figure Legends...19

Figures...21

About this Honors Thesis

Rights statement
  • Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.
School
Department
Degree
Submission
Language
  • English
Research field
关键词
Committee Chair / Thesis Advisor
Committee Members
最新修改

Primary PDF

Supplemental Files