title: Phenotypic characterization of a novel double knockout PknI/DacB2 from Mycobacterium tuberculosis.
abstract: Serine/threonine protein kinases play a major role in peptidoglycan biosynthesis in Mycobacterium tuberculosis. To explore the mechanism in detail, in the present study, we have constructed a double knockout (DKO) strain lacking pknI and dacB2 in M. tuberculosis. Initially, we analyzed the colony morphology and found that the DKO strain showed smoother colony morphology on solid agar and irregular shape in transmission electron microscopy. In addition, the DKO strain exhibits defective biofilm and cord formation. The DKO strain was found to be hypersensitive to cell wall damaging agents such as lysozyme, malachite green, ethidium bromide and to isoniazid, a first line anti-TB drug. In conclusion, our data suggest that both pknI and dacB2 play an important role in the maintenance of colony morphology, cell wall permeability and integrity of M. tuberculosis.
authors.affiliation: Department of Immunology, National Institute for Research in Tuberculosis (NIRT), Mayor V R Ramanathan Road, Chetpet, Chennai 600 031, Tamilnadu, India.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Kandasamy
authors.affiliation: Department of Immunology, National Institute for Research in Tuberculosis (NIRT), Mayor V R Ramanathan Road, Chetpet, Chennai 600 031, Tamilnadu, India. Electronic address: sujatha.sujatha36@gmail.com.
authors.forename: Sujatha
authors.initials: S
authors.lastname: Narayanan
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D018441:Biofilms; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D008826:Microbial Sensitivity Tests; D009113:Muramidase; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism* / Q000648:ultrastructure; D010641:Phenotype
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D009113:Muramidase
keywords: Biofilm; Colony morphology; Cording; MIC; Mycobacterium tuberculosis; PBP; STPK; Transmission electron microscope