%0 Journal Article %1 schielke_transcriptional_2010 %A Schielke, Stephanie %A Schmitt, Corinna %A Spatz, Carolin %A Frosch, Matthias %A Schubert-Unkmeir, Alexandra %A Kurzai, Oliver %D 2010 %J Applied and Environmental Microbiology %K A, Acid Acids, Agents, Bacterial Bacterial, Drug Fatty Lipid Lipopolysaccharides, Mutation, Neisseria Palmitic Proteins, Resistance, ag_unkmeir gonorrhoeae, meningitidis, {Anti-Bacterial} %N 10 %P 3160--3169 %R 10.1128/AEM.02833-09 %T The transcriptional repressor FarR is not involved in meningococcal fatty acid resistance mediated by the FarAB efflux pump and dependent on lipopolysaccharide structure %U http://www.ncbi.nlm.nih.gov/pubmed/20348314 %V 76 %X Free fatty acids are important antimicrobial substances regulating the homeostasis of colonizing bacteria on epithelial surfaces. Here, we show that meningococci express a functional farAB efflux pump, which is indispensable for fatty acid resistance. However, other than in Neisseria gonorrhoeae, the transcriptional regulator FarR is not involved in regulation of this operon in Neisseria meningitidis. We tested the susceptibility of 23 meningococcal isolates against saturated and unsaturated long-chain fatty acids, proving that meningococci are generally highly resistant, with the exception of serogroup Y strains belonging to sequence type 23. Using genetically determined lipopolysaccharide (LPS)-truncated mutant strains, we show that addition of the LPS core oligosaccharide and hexa-acylation of its membrane anchor lipid A are imperative for fatty acid resistance of meningococci. The sensitivity of the serogroup Y strains is due to naturally occurring mutations within the lpxL1 gene, which is responsible for addition of the sixth acyl chain on the LPS membrane anchor lipid A. Therefore, fatty acid resistance in meningococci is provided by both the active efflux pump FarAB and by the natural permeability barrier of the Gram-negative outer membrane. The transcriptional regulator FarR is not implicated in fatty acid resistance in meningococci, possibly giving rise to a constitutively active FarAB efflux pump system and thus revealing diverse mechanisms of niche adaptation in the two closely related Neisseria species.

@article{schielke_transcriptional_2010, abstract = {Free fatty acids are important antimicrobial substances regulating the homeostasis of colonizing bacteria on epithelial surfaces. Here, we show that meningococci express a functional {farAB} efflux pump, which is indispensable for fatty acid resistance. However, other than in Neisseria gonorrhoeae, the transcriptional regulator {FarR} is not involved in regulation of this operon in Neisseria meningitidis. We tested the susceptibility of 23 meningococcal isolates against saturated and unsaturated long-chain fatty acids, proving that meningococci are generally highly resistant, with the exception of serogroup Y strains belonging to sequence type 23. Using genetically determined lipopolysaccharide {(LPS)-truncated} mutant strains, we show that addition of the {LPS} core oligosaccharide and hexa-acylation of its membrane anchor lipid A are imperative for fatty acid resistance of meningococci. The sensitivity of the serogroup Y strains is due to naturally occurring mutations within the {lpxL1} gene, which is responsible for addition of the sixth acyl chain on the {LPS} membrane anchor lipid A. Therefore, fatty acid resistance in meningococci is provided by both the active efflux pump {FarAB} and by the natural permeability barrier of the Gram-negative outer membrane. The transcriptional regulator {FarR} is not implicated in fatty acid resistance in meningococci, possibly giving rise to a constitutively active {FarAB} efflux pump system and thus revealing diverse mechanisms of niche adaptation in the two closely related Neisseria species.}, added-at = {2011-04-07T15:44:20.000+0200}, author = {Schielke, Stephanie and Schmitt, Corinna and Spatz, Carolin and Frosch, Matthias and {Schubert-Unkmeir}, Alexandra and Kurzai, Oliver}, biburl = {https://www.bibsonomy.org/bibtex/224d0f4722a27fd0c676e13215c3f7823/hymi}, doi = {10.1128/AEM.02833-09}, interhash = {00b94f8681fbe4aa43ea51525d7d07ca}, intrahash = {24d0f4722a27fd0c676e13215c3f7823}, issn = {1098-5336}, journal = {Applied and Environmental Microbiology}, keywords = {A, Acid Acids, Agents, Bacterial Bacterial, Drug Fatty Lipid Lipopolysaccharides, Mutation, Neisseria Palmitic Proteins, Resistance, ag_unkmeir gonorrhoeae, meningitidis, {Anti-Bacterial}}, month = may, note = {{PMID:} 20348314}, number = 10, pages = {3160--3169}, timestamp = {2011-04-07T16:28:36.000+0200}, title = {The transcriptional repressor {FarR} is not involved in meningococcal fatty acid resistance mediated by the {FarAB} efflux pump and dependent on lipopolysaccharide structure}, url = {http://www.ncbi.nlm.nih.gov/pubmed/20348314}, volume = 76, year = 2010 }