title: Linking carbon metabolism to carotenoid production in mycobacteria using Raman spectroscopy.
abstract: Bacteria can utilize multiple sources of carbon for growth, and for pathogenic bacteria like Mycobacterium tuberculosis, this ability is crucial for survival within the host. In addition, phenotypic changes are seen in mycobacteria grown under different carbon sources. In this study, we use Raman spectroscopy to analyze the biochemical components present in M. smegmatis cells when grown in three differently metabolized carbon sources. Our results show that carotenoid biosynthesis is enhanced when M. smegmatis is grown in glucose compared to glycerol and acetate. We demonstrate that this difference is most likely due to transcriptional upregulation of the carotenoid biosynthesis operon (crt) mediated by higher levels of the stress-responsive sigma factor SigF. Moreover, we find that increased SigF and carotenoid levels correlate with greater resistance of glucose-grown cells to oxidative stress. Thus, we demonstrate the use of Raman spectroscopy in unraveling unknown aspects of mycobacterial physiology and describe a novel effect of carbon source variation on mycobacteria.
authors: Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
authors: Srividya
authors: S
authors: Kumar
authors: Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India.
authors: Nishad
authors: N
authors: Matange
authors: Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India Bioengineering Programme, Indian Institute of Science, Bangalore 560012, India Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012, India.
authors: Siva
authors: S
authors: Umapathy
authors: Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India Bioengineering Programme, Indian Institute of Science, Bangalore 560012, India sandhya@mrdg.iisc.ernet.in.
authors: Sandhya S
authors: SS
authors: Visweswariah
mesh_terms: D000085:Acetates / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D002244:Carbon / Q000378:metabolism*; D002338:Carotenoids / Q000096:biosynthesis*; D005947:Glucose / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D020102:Mycobacterium smegmatis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D009876:Operon; D018384:Oxidative Stress; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000378:metabolism; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D000085:Acetates; D001426:Bacterial Proteins; C064971:FliA protein, Bacteria; D012808:Sigma Factor; D002338:Carotenoids; D002244:Carbon; D005947:Glucose; D005990:Glycerol
keywords: Raman spectroscopy; SigF; carotenoids; mycobacteria