title: MSMEG_5684 down-regulation in Mycobacterium smegmatis affects its permeability, survival under stress and persistence.
abstract: The Mycobacterium tuberculosis (Mtb) genome sequence and annotation details have been available for a long time; however physiological relevance of many ORFs remains poorly described. Mtb is a pathogenic strain; hence, surrogate strains such as Mycobacterium bovis BCG and Mycobacterium smegmatis (Msmeg) have also been studied to gain an understanding of mycobacterial physiology and metabolism. The Mycobacterium smegmatis mc2155 ORF MSMEG_5684 is annotated as a part of serine biosynthetic pathway, however, its physiological significance remains to be established experimentally. To understand the relevance of SerC for Msmeg physiology we developed a recombinant Mycobacterium smegmatis with SerC knockdown (KD) and also complemented it with serC over-expressing construct (KDC). The KD showed reduced growth compared to wild-type (WT) and complemented strain on glycerol as carbon source. The growth of KD was restored after supplementation of serine. The survival studies with WT and KD under oxidative, nitrosative and detergent stresses showed increased susceptibility of KD. The KD also showed increased susceptibility to antimycobacterial agents and poor ability for in vitro persistence. Also, the serC transcript profiling showed increased expression under stress. The complementation studies with Msmeg serC showed growth restoration of E. coli-ΔserC in minimal medium.
authors.affiliation: Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India.
authors.forename: Deepa
authors.initials: D
authors.lastname: Keshari
authors.affiliation: Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India.
authors.forename: Kumar Sachin
authors.initials: KS
authors.lastname: Singh
authors.affiliation: Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India.
authors.forename: Rishabh
authors.initials: R
authors.lastname: Sharma
authors.affiliation: Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India.
authors.forename: Shailendra
authors.initials: S
authors.lastname: Yadav
authors.affiliation: Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi, India. Electronic address: sudheer_singh@cdri.res.in.
authors.forename: Sudheer Kumar
authors.initials: SK
authors.lastname: Singh
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003902:Detergents / Q000633:toxicity; D015536:Down-Regulation; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005838:Genotype; D050296:Microbial Viability; D020102:Mycobacterium smegmatis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D020030:Nitric Oxide Donors / Q000633:toxicity; D016877:Oxidants / Q000633:toxicity; D018384:Oxidative Stress; D010539:Permeability; D010641:Phenotype; D013312:Stress, Physiological; D013997:Time Factors; D000637:Transaminases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D003902:Detergents; D020030:Nitric Oxide Donors; D016877:Oxidants; D000637:Transaminases; C022393:phosphoserine aminotransferase
keywords: Knockdown; Mycobacterium smegmatis; Permeability; Persistence; Phosphoserine aminotransferase; Stress