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Isolation and regulation of Sinorhizobium meliloti 1021 loci induced by oxygen limitation.

ABSTRACT: Eleven Sinorhizobium meliloti 1021 loci whose expression was induced under low oxygen concentrations were identified in a collection of 5,000 strains carrying Tn5-1063 (luxAB) transcriptional reporter gene fusions. The 11 Tn5-1063-tagged loci were cloned and characterized. The dependence of the expression of the tagged loci on the FixL/FixJ oxygen-sensing two-component regulatory system was examined. Three of the loci were found to be dependent upon fixL and fixJ for their expression, while one locus showed a partial dependence. The remaining seven loci showed fixL- and fixJ-independent induction of expression in response to oxygen limitation. This suggests that in S. meliloti, additional regulatory system(s) exist that respond either directly or indirectly to oxygen limitation conditions.

SUBMITTER: Trzebiatowski JR

PROVIDER: S-EPMC93079 | biostudies-literature | 2001 Aug

REPOSITORIES: biostudies-literature

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Isolation and regulation of Sinorhizobium meliloti 1021 loci induced by oxygen limitation.

Trzebiatowski J R JR Ragatz D M DM de Bruijn F J FJ

Applied and environmental microbiology 20010801 8

Eleven Sinorhizobium meliloti 1021 loci whose expression was induced under low oxygen concentrations were identified in a collection of 5,000 strains carrying Tn5-1063 (luxAB) transcriptional reporter gene fusions. The 11 Tn5-1063-tagged loci were cloned and characterized. The dependence of the expression of the tagged loci on the FixL/FixJ oxygen-sensing two-component regulatory system was examined. Three of the loci were found to be dependent upon fixL and fixJ for their expression, while one ...[more]

PMID: 11472955

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Biotin limitation in Sinorhizobium meliloti strain 1021 alters transcription and translation.

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Sinorhizobium meliloti cells: untreated 1021 strain vs. 1021 treated with tryptophan (Trp)

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2010-05-20 | GSE21743 | GEO

Sinorhizobium meliloti cells: untreated 1021 strain vs. 1021 treated with indole (IND)

2010-05-20 | GSE21742 | GEO

Genetic organization of the region encoding regulation, biosynthesis, and transport of rhizobactin 1021, a siderophore produced by Sinorhizobium meliloti.

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Project description:Effect of deletion of DivJ kinase on the transcriptome of Sinorhizobium meliloti 1021.

2013-07-29 | E-MEXP-3942 | biostudies-arrayexpress

Sinorhizobium meliloti phospholipase C required for lipid remodeling during phosphorus limitation.

Project description:Rhizobia are Gram-negative soil bacteria able to establish nitrogen-fixing root nodules with their respective legume host plants. Besides phosphatidylglycerol, cardiolipin, and phosphatidylethanolamine, rhizobial membranes contain phosphatidylcholine (PC) as a major membrane lipid. Under phosphate-limiting conditions of growth, some bacteria replace their membrane phospholipids with lipids lacking phosphorus. In Sinorhizobium meliloti, these phosphorus-free lipids are sulfoquinovosyl diacylglycerol, ornithine-containing lipid, and diacylglyceryl trimethylhomoserine (DGTS). Pulse-chase experiments suggest that the zwitterionic phospholipids phosphatidylethanolamine and PC act as biosynthetic precursors of DGTS under phosphorus-limiting conditions. A S. meliloti mutant, deficient in the predicted phosphatase SMc00171 was unable to degrade PC or to form DGTS in a similar way as the wild type. Cell-free extracts of Escherichia coli, in which SMc00171 had been expressed, convert PC to phosphocholine and diacylglycerol, showing that SMc00171 functions as a phospholipase C. Diacylglycerol , in turn, is the lipid anchor from which biosynthesis is initiated during the formation of the phosphorus-free membrane lipid DGTS. Inorganic phosphate can be liberated from phosphocholine. These data suggest that, in S. meliloti under phosphate-limiting conditions, membrane phospholipids provide a pool for metabolizable inorganic phosphate, which can be used for the synthesis of other essential phosphorus-containing biomolecules. This is an example of an intracellular phospholipase C in a bacterial system; however, the ability to degrade endogenous preexisting membrane phospholipids as a source of phosphorus may be a general property of Gram-negative soil bacteria.

| S-EPMC2806695 | biostudies-literature

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