Document Detail

Physiological and molecular genetic evaluation of the dechlorination agent, pyridine-2,6-bis(monothiocarboxylic acid) (PDTC) as a secondary siderophore of Pseudomonas.
MedLine Citation:
PMID:  14756880     Owner:  NLM     Status:  MEDLINE    
The bacterial metabolite and transition metal chelator pyridine-2,6-dithiocarboxylic acid (PDTC), promotes a novel and effective means of dechlorination of the toxic and carcinogenic pollutant, carbon tetrachloride. Pyridine-2,6-dithiocarboxylic acid has been presumed to act as a siderophore in the Pseudomonas strains known to produce it. To explore further the physiological function of PDTC production, we have examined its regulation, the phenotype of PDTC-negative (pdt) mutants, and envelope proteins associated with PDTC in P. putida strain DSM 3601. Aspects of the regulation of PDTC production and outer membrane protein composition were consistent with siderophore function. Pyridine-2,6-dithiocarboxylic acid production was coordinated with production of the well-characterized siderophore pyoverdine; exogenously added pyoverdine led to decreased PDTC production, and added PDTC led to decreased pyoverdine production. Positive regulation of a chromosomal pdtI-xylE transcriptional fusion, and of a 66 kDa outer membrane protein (IROMP), was seen in response to exogenous PDTC. Tests with transition metal chelators indicated that PDTC could provide a benefit under conditions of metal limitation; the loss of PDTC biosynthetic capacity caused by a pdtI transposon insertion resulted in increased sensitivity to 1,10-phenanthroline, a chelator that has high affinity for a range of divalent transition metals (e.g. Fe(2+), Cu(2+), Zn(2+)). Exogenously added PDTC could also suppress a phenotype of pyoverdine-negative (Pvd-) mutants, that of sensitivity to EDDHA, a chelator with higher affinity and specificity for Fe(3+). Measurement of 59Fe incorporation showed uptake from 59Fe:PDTC by DSM 3601 grown in low-iron medium, but not by cells grown in high iron medium, or by the pdtI mutant, which did not show expression of the 66 kDa envelope protein. These data verified a siderophore function for PDTC, and have implicated it in the uptake of transition metals in addition to iron.
Thomas A Lewis; Lynne Leach; Sergio Morales; Paula R Austin; Hadley J Hartwell; Benjamin Kaplan; Cynthia Forker; Jean-Marie Meyer
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Environmental microbiology     Volume:  6     ISSN:  1462-2912     ISO Abbreviation:  Environ. Microbiol.     Publication Date:  2004 Feb 
Date Detail:
Created Date:  2004-02-03     Completed Date:  2004-05-04     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100883692     Medline TA:  Environ Microbiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  159-69     Citation Subset:  IM    
Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA.
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MeSH Terms
Bacterial Proteins / genetics,  metabolism
Chlorine / metabolism
Genes, Reporter
Iron / metabolism
Iron Chelating Agents / metabolism
Molecular Biology
Pigments, Biological / genetics,  metabolism
Pseudomonas / genetics,  metabolism*
Pyridines / metabolism*
Siderophores / genetics,  metabolism*
Reg. No./Substance:
0/Bacterial Proteins; 0/Iron Chelating Agents; 0/Oligopeptides; 0/Pigments, Biological; 0/Pyridines; 0/Siderophores; 0/pyridine-2,6-bis(thiocarboxylic acid); 7439-89-6/Iron; 7782-50-5/Chlorine; 8062-00-8/pyoverdin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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