title: The Non-Essential Mycolic Acid Biosynthesis Genes hadA and hadC Contribute to the Physiology and Fitness of Mycobacterium smegmatis.
abstract: Gram positive mycobacteria with a high GC content, such as the etiological agent of tuberculosis Mycobacterium tuberculosis, possess an outer membrane mainly composed of mycolic acids (MAs), the so-called mycomembrane, which is essential for the cell. About thirty genes are involved in the biosynthesis of MAs, which include the hadA, hadB and hadC genes that encode the dehydratases Fatty Acid Synthase type II (FAS-II) known to function as the heterodimers HadA-HadB and HadB-HadC. The present study shows that M. smegmatis cells remain viable in the absence of either HadA and HadC or both. Inactivation of HadC has a dramatic effect on the physiology and fitness of the mutant strains whereas that of HadA exacerbates the phenotype of a hadC deletion. The hadC mutants exhibit a novel MA profile, display a distinct colony morphology, are less aggregated, are impaired for sliding motility and biofilm development and are more resistant to detergent. Conversely, the hadC mutants are significantly more susceptible to low- and high-temperature and to selective toxic compounds, including several current anti-tubercular drugs.
authors.affiliation: Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France.|Univ. Toulouse, UPS, F-31000 Toulouse, France.
authors.forename: Stevie
authors.initials: S
authors.lastname: Jamet
authors.affiliation: Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France.|Univ. Toulouse, UPS, F-31000 Toulouse, France.
authors.forename: Nawel
authors.initials: N
authors.lastname: Slama
authors.affiliation: Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France.|Univ. Toulouse, UPS, F-31000 Toulouse, France.
authors.forename: Joana
authors.initials: J
authors.lastname: Domingues
authors.affiliation: Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France.|Univ. Toulouse, UPS, F-31000 Toulouse, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Laval
authors.affiliation: Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France.|Univ. Toulouse, UPS, F-31000 Toulouse, France.
authors.forename: Pauline
authors.initials: P
authors.lastname: Texier
authors.affiliation: Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France.|Univ. Toulouse, UPS, F-31000 Toulouse, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Eynard
authors.affiliation: Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France.|Univ. Toulouse, UPS, F-31000 Toulouse, France.
authors.forename: Annaik
authors.initials: A
authors.lastname: Quémard
authors.affiliation: Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France.|Univ. Toulouse, UPS, F-31000 Toulouse, France.
authors.forename: Antonio
authors.initials: A
authors.lastname: Peixoto
authors.affiliation: Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France.|Univ. Toulouse, UPS, F-31000 Toulouse, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Lemassu
authors.affiliation: Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France.|Univ. Toulouse, UPS, F-31000 Toulouse, France.
authors.forename: Mamadou
authors.initials: M
authors.lastname: Daffé
authors.affiliation: Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France.|Univ. Toulouse, UPS, F-31000 Toulouse, France.
authors.forename: Kaymeuang
authors.initials: K
authors.lastname: Cam
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002470:Cell Survival; D008826:Microbial Sensitivity Tests; D009165:Mycobacterium Infections, Nontuberculous / Q000378:metabolism* / Q000382:microbiology; D020102:Mycobacterium smegmatis / Q000502:physiology*; D009171:Mycolic Acids / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D009171:Mycolic Acids