%0 Journal Article
%T Stress Responses of Shewanella
%A Jianhua Yin
%A Haichun Gao
%J International Journal of Microbiology
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/863623
%X The shewanellae are ubiquitous in aquatic and sedimentary systems that are chemically stratified on a permanent or seasonal basis. In addition to their ability to utilize a diverse array of terminal electron acceptors, the microorganisms have evolved both common and unique responding mechanisms to cope with various stresses. This paper focuses on the response and adaptive mechanism of the shewanellae, largely based on transcriptional data. 1. Introduction Stress is an inevitable part of the life of all organisms. This is especially true about microorganisms, which reside and thrive in almost all environments on earth, including some considered extremely harsh [1]. Common environmental factors that affect the activities of microorganisms include temperature, pH, water availability, nutrient limitation, presence of various chemicals, osmolarity, pressure, and radiation [2]. Consequently, for every microorganism the ability to adapt rapidly to changes in environments is essential for its survival and prosperity. Regulation that modulates the microbial adaptation to environmental disturbances is rather complex. The most important and efficient control occurs at the level of transcription. Many single stress-induced regulatory circuits have been identified, which enable cells to cope with specific stresses. However, given that microbial cells live in a dynamic environment where multiple factors fluctuate constantly at the same time, stress responses are generally carried out by a regulatory network composed of a series of individual circuits which are highly connected [3]. Most of our understanding of microbial stress response mechanisms has come from the study of model microorganisms, particularly Escherichia coli and Bacillus subtilis. Extensive physiological and genetic analyses of the stress response systems in these two bacteria have helped us to elucidate the complexity of the process, function of critical proteins, and regulation [4]. While model organisms will continue to provide insights into the fundamental properties of the stress response systems, efforts should be extended to other microorganisms, especially those that are of scientific, environmental, and economic importance. As one of representatives, the family of Shewanellaceae (order Alteromonadales, class ¦Ã-proteobacteria) is emerging in recent years. The genus Shewanella consists of rod-shaped, Gram-negative, aerobic or facultatively anaerobic, polarly flagellated, readily cultivated ¦Ã-proteobacteria [5¨C8]. While many Shewanella isolates remain uncharacterized, 52 species have been
%U http://www.hindawi.com/journals/ijmicro/2011/863623/