New structural and functional defects in polyphosphate deficient bacteria: A cellular and proteomic study

BMC Microbiology

Research Article

Cecilia Mauriaca¹  Cristian Varela¹  Francisco P Chávez¹  Carlos A Jerez¹  Alberto Paradela²  Juan P Albar² 

[1] Laboratory of Molecular Microbiology and Biotechnology & Millennium Institute of Cell Dynamics and Biotechnology (ICDB), Department of Biology, Faculty of Sciences, University of Chile, Las Palmeras, 3425, Ñuñoa, Santiago, Chile;Servicio de Proteómica, Centro Nacional de Biotecnología, CSIC. Darwin 3, 28049, Madrid, España;

关键词: Amino Acid Biosynthesis;    Functional Defect;    Nucleoside Triphosphate;    Polyphosphate Kinase;    Ammonium Bicarbonate Solution;   

DOI  :  10.1186/1471-2180-10-7

 received in 2009-08-10, accepted in 2010-01-12,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundInorganic polyphosphate (polyP), a polymer of tens or hundreds of phosphate residues linked by ATP-like bonds, is found in all organisms and performs a wide variety of functions. PolyP is synthesized in bacterial cells by the actions of polyphosphate kinases (PPK1 and PPK2) and degraded by exopolyphosphatase (PPX). Bacterial cells with polyP deficiencies due to knocking out the ppk1 gene are affected in many structural and important cellular functions such as motility, quorum sensing, biofilm formation and virulence among others. The cause of this pleiotropy is not entirely understood.ResultsThe overexpression of exopolyphosphatase in bacteria mimicked some pleitropic defects found in ppk1 mutants. By using this approach we found new structural and functional defects in the polyP-accumulating bacteria Pseudomonas sp. B4, which are most likely due to differences in the polyP-removal strategy. Colony morphology phenotype, lipopolysaccharide (LPS) structure changes and cellular division malfunction were observed. Finally, we used comparative proteomics in order to elucidate the cellular adjustments that occurred during polyP deficiency in this bacterium and found some clues that helped to understand the structural and functional defects observed.ConclusionsThe results obtained suggest that during polyP deficiency energy metabolism and particularly nucleoside triphosphate (NTP) formation were affected and that bacterial cells overcame this problem by increasing the flux of energy-generating metabolic pathways such as tricarboxilic acid (TCA) cycle, β-oxidation and oxidative phosphorylation and by reducing energy-consuming ones such as active transporters and amino acid biosynthesis. Furthermore, our results suggest that a general stress response also took place in the cell during polyP deficiency.

【 授权许可】

Unknown   
© Varela et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.