title: Vitamin C induced DevR-dependent synchronization of Mycobacterium smegmatis growth and its effect on the proliferation of mycobacteriophage D29.
abstract: Vitamin C is known to inhibit mycobacterial growth by acting as a hypoxia inducing agent. While investigating how mycobacteriophage growth is influenced by hypoxic conditions induced by vitamin C, using Mycobacterium smegmatis- mycobacteriophage D29 as a model system, it was observed that prior exposure of the host to such conditions resulted in increased burst size of the phage. Vitamin C pre-exposure was also found to induce synchronous growth of the host. A mutant defective in DevR, the response regulator that controls hypoxic responses in mycobacteria, neither supported higher phage bursts nor was it able to undergo synchronized growth following vitamin C pre-exposure, indicating thereby that the two phenomena are interrelated. Further evidence supporting such an interrelationship was obtained from the observation that phage burst sizes varied depending on the stage of synchronous growth that the host cells were in, at the time of infection-higher bursts were observed in the resting/synthetic phases and lower in the dividing ones. The effects were specific in nature as synchronization by an unrelated method, known as 'crowding', did not lead to the same consequence. The results indicate that growth synchronization induced by vitamin C treatment is a DevR-dependent phenomenon which is exploited by mycobacteriophage D29 to grow in larger numbers.
authors.affiliation: Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India.
authors.forename: Prithwiraj
authors.initials: P
authors.lastname: Kirtania
authors.affiliation: Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India.
authors.forename: Shreya
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India.
authors.forename: Niketa
authors.initials: N
authors.lastname: Bhawsinghka
authors.affiliation: Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India.
authors.forename: Madhumita
authors.initials: M
authors.lastname: Chakladar
authors.affiliation: Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India sujoy@jcbose.ac.in.
authors.forename: Sujoy K
authors.initials: SK
authors.lastname: Das Gupta
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D009160:Mycobacteriophages / Q000502:physiology*; D020102:Mycobacterium smegmatis / Q000254:growth & development* / Q000502:physiology*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C542863:DosR protein, Mycobacterium tuberculosis; D011494:Protein Kinases; D001205:Ascorbic Acid
keywords: Mycobacterium smegmatis; dormancy; hypoxia; mycobacteriophage; vitamin C