Find in Library

<p>Abstract</p> <p>Background</p> <p>The response of the NarQP two-component signal transduction system regulon in response to the presence of nitrate for the bovine pathogen <it>Mannheimia haemolytica </it>A1 was investigated by proteomic analysis. Total proteins from a <it>narP </it>mutant and the parent SH1217 grown with or without NaNO₃supplement were examined by ISO-DALT 2D electrophoresis and liquid chromatography-mass spectrometry.</p> <p>Results</p> <p>Seventeen proteins were differentially expressed in the parent strain SH1217 in response to the addition of NaNO₃to the growth media. These responses were absent in the <it>narP </it>mutant, indicating that the altered production of these proteins is mediated by NarP_<it>Mh</it>. Interestingly, NarP_{<it>Mh </it>}mediated the increased production of some proteins which are not generally associated with nitrate respiration, such as the iron transporters FbpA and YfeA. The increased production of proteins such as superoxide dismutase, SodA, and GAPDH were also observed. The increased production of these iron-regulated proteins by NarP_{<it>Mh </it>}is thought to enhance the swift establishment of the nitrate respiration mechanism of <it>M. haemolytica </it>during pathogenesis.</p> <p>Conclusion</p> <p>The data suggested NarP_{<it>Mh </it>}acts as an important regulator which regulates the expression of a small set of proteins in response to nitrate availability. This may contribute to the prevalence of <it>M. haemolytica </it>A1 in its host during pathogenesis of BPP, through enhancing the effectiveness of nitrate respiration either directly or indirectly.</p>