Document Detail


Unsaturated fatty acids are inhibitors of bacterial conjugation.
MedLine Citation:
PMID:  16272375     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This report describes a high-throughput assay to identify substances that reduce the frequency of conjugation in Gram-negative bacteria. Bacterial conjugation is largely responsible for the spread of multiple antibiotic resistances in human pathogens. Conjugation inhibitors may provide a means to control the spread of antibiotic resistance. An automated conjugation assay was developed that used plasmid R388 and a laboratory strain of Escherichia coli as a model system, and bioluminescence as a reporter for conjugation activity. Frequencies of conjugation could be measured continuously in real time by the amount of light produced, and thus the effects of inhibitory compounds could be determined quantitatively. A control assay, run in parallel, allowed elimination of compounds affecting cell growth, plasmid stability or gene expression. The automated conjugation assay was used to screen a database of more than 12,000 microbial extracts known to contain a wide variety of bioactive compounds (the NatChem library). The initial hit rate was 1.4 %. From these, 48 extracts containing active compounds and representing a variety of organisms and extraction conditions were subjected to fractionation (24 fractions per extract). The 52 most active fractions were subjected to a secondary analysis to determine the range of plasmid inhibition. Plasmids R388, R1 and RP4 were used as representatives of a variety of plasmid transfer systems. Only one fraction (of complex composition) affected transfer of all three plasmids, while four other fractions were active against two of them. Two separate compounds were identified from these fractions: linoleic acid and dehydrocrepenynic acid. Downstream analysis showed that the chemical class of unsaturated fatty acids act as true inhibitors of conjugation.
Authors:
Raul Fernandez-Lopez; Cristina Machón; Christopher M Longshaw; Steve Martin; Soren Molin; Ellen L Zechner; Manuel Espinosa; Erich Lanka; Fernando de la Cruz
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Publication Detail:
Type:  Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Microbiology (Reading, England)     Volume:  151     ISSN:  1350-0872     ISO Abbreviation:  Microbiology (Reading, Engl.)     Publication Date:  2005 Nov 
Date Detail:
Created Date:  2005-11-07     Completed Date:  2005-12-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9430468     Medline TA:  Microbiology     Country:  England    
Other Details:
Languages:  eng     Pagination:  3517-26     Citation Subset:  IM    
Affiliation:
Departamento de Biología Molecular (Unidad asociada al CIB, CSIC), Universidad de Cantabria, C. Herrera Oria s/n, E-39011 Santander, Spain.
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MeSH Terms
Descriptor/Qualifier:
Conjugation, Genetic / drug effects*
Drug Resistance, Bacterial / genetics
Escherichia coli / drug effects,  genetics,  growth & development
Fatty Acids, Unsaturated / pharmacology*
Gram-Negative Bacteria / drug effects*,  genetics,  growth & development
Humans
Luminescence
Microbial Sensitivity Tests / methods
R Factors / genetics*
Chemical
Reg. No./Substance:
0/Fatty Acids, Unsaturated

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


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