Download or read book A Novel Mode of Bacterial Respiration written by Christine Michelle Fennessey and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial iron respiration contributes significantly to the biogeochemical cycling of metals and may be one of the earliest respiratory processes to have evolved on early earth. Metal-respiring microbes also hold great potential for use in microbial fuel cells for the generation of "green" energy and for remediation of radionuclides in contaminated environments. Despite its significance in global metal cycling processes, the molecular mechanism of Fe(III) respiration has yet to be determined. Unlike many other terminal electron acceptors, Fe(III) is a solid at circumneutral pH and, therefore, cannot come into direct contact with the microbial inner membrane: the site of terminal electron transfer in gram-negative bacteria. It is postulated that metal-respiring organisms have developed alternate strategies for the reduction of solid iron. One such strategy involves the production of an Fe(III)-solublizing ligand by the metal-respiring bacteria which solubilizes the Fe(III) prior to respiration, rendering the metal more easily accessible to the Fe(III) reductase complex. :In this study, the genes involved in the solubilization of Fe(III) by the gram-negative dissimilatory metal reducing bacteria Shewanella oneidensis MR-1 were determined using random mutagenesis to generate mutations in the wild-type genome and high-throughput square-wave voltammetry to screen for the attenuation of Fe(III) production in the mutants. Two mutants unable to solubilize Fe(III) were identified and designated d29 and d64. After mutation complementation analysis, it was determined that the point mutations were both located in type II secretion genes: gspG and gspE respectively, indicating that the type II secretion system is required for Fe(III) solubilization prior to respiration.