| Identification and functional analysis of the cyclopropane fatty acid synthase of Brucella abortus. | |
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MedLine Citation:
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PMID: 22262102 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The brucellae are facultative intracellular pathogens of mammals that are transmitted by contact with infected animals or contaminated materials. Several major lipidic components of the Brucella cell envelope are imperfectly recognized by innate immunity thus contributing to virulence. These components carry large proportions of acyl chains of lactobacillic acid, a long chain cyclopropane fatty acid (CFA). CFAs result from addition of a methylene group to unsaturated acyl chains and contribute to resistance to acidity, dryness and high osmolarity in many bacteria and to virulence in mycobacteria. We examined the role of lactobacillic acid in B. abortus virulence by creating a mutant in ORF BAB1_0476, the putative CFA synthase gene. The mutant did not incorporate [14C]-methyl groups into lipids, lacked CFAs and synthesized the unsaturated precursors, proving that BAB1_0476 actually encodes a CFA synthase. BAB1_0476 promotor-luxAB fusion studies showed that CFA synthase expression was promoted by acid pH and high osmolarity. The mutant was not attenuated in macrophages or mice, strongly suggesting that CFAs are not essential for B. abortus intracellular life. However, when the mutant was tested under high osmolarity on agar and acid pH, two conditions likely to occur on contaminated materials and fomites, they showed reduced ability to growth or survive. Since CFA synthesis entails high ATP expenses and Brucella produces large proportions of lactobacillic acyl chains, we propose that the CFA synthase has been conserved because it is useful to survive extracellularly, thus facilitating the persistence in contaminated materials and the transmission to new hosts. |
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Authors:
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Leyre Palacios-Chaves; Amaia Zúñiga-Ripa; Ana Gutiérrez; Yolanda Gil-Ramírez; Raquel Conde-Álvarez; Ignacio Moriyón; Maite Iriarte |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-1-19 |
Journal Detail:
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Title: Microbiology (Reading, England) Volume: - ISSN: 1465-2080 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
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Created Date: 2012-1-20 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9430468 Medline TA: Microbiology Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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University of Navarra; |
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Descriptor/Qualifier:
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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