title: Peptidoglycan fragments stimulate resuscitation of "non-culturable" mycobacteria.
abstract: Resuscitation promoting factors (Rpfs), belonging to a family of secreted actinobacterial proteins with predicted peptidoglycan (PG) hydrolytic activities, participate in the reactivation of dormant cells. In the present study we demonstrate that a recombinant truncated form of Micrococcus luteus Rpf hydrolyzes isolated PG of Mycobacterium smegmatis and Mycobacterium tuberculosis liberating PG fragments of different size. These fragments possess stimulatory activity toward "non-culturable" dormant M. smegmatis and M. tuberculosis cells, similar to the activity of recombinant Rpf. Relatively large PG fragments (0.1-0.5 μm) obtained either by Rpf digestion or by PG ultrasonication revealed resuscitation activities when added in concentrations 0.1-0.2 μg/ml to the resuscitation medium. It is suggested that PG fragments could either directly activate the resuscitation pathway of dormant mycobacteria or serve as a substrate for endogenous Rpf, resulting in low molecular weight products with resuscitation activity. Whilst both suggestions are plausible, it was observed that PG-dependent resuscitation activity was suppressed by means of a specific Rpf inhibitor (4-benzoyl-2-nitrophenylthiocyanate), which provides additional support for the second of these possibilities.
authors.affiliation: A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, Moscow, 119071, Russia. vadimchemist@gmail.com
authors.forename: Vadim D
authors.initials: VD
authors.lastname: Nikitushkin
authors.forename: Galina R
authors.initials: GR
authors.lastname: Demina
authors.forename: Margarita O
authors.initials: MO
authors.lastname: Shleeva
authors.forename: Arseny S
authors.initials: AS
authors.lastname: Kaprelyants
mesh_terms: D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D016207:Cytokines / Q000302:isolation & purification / Q000378:metabolism*; D006868:Hydrolysis; D016982:Micrococcus luteus / Q000201:enzymology; D020102:Mycobacterium smegmatis / Q000737:chemistry / Q000254:growth & development*; D009169:Mycobacterium tuberculosis / Q000737:chemistry / Q000254:growth & development*; D010457:Peptidoglycan / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D016207:Cytokines; D010457:Peptidoglycan; C113704:resuscitation-promoting factor, bacteria