Sporulation in mycobacteria.
Mycobacteria owe their success as pathogens to their ability to persist for long periods within host cells in asymptomatic, latent forms before they opportunistically switch to the virulent state. The molecular mechanisms underlying the transition into dormancy and emergence from it are not clear. Here we show that old cultures of Mycobacterium marinum contained spores that, upon exposure to fresh medium, germinated into vegetative cells and reappeared again in stationary phase via endospore formation. They showed many of the usual characteristics of well-known endospores. Homologues of well-known sporulation genes of Bacillus subtilis and Streptomyces coelicolor were detected in mycobacteria genomes, some of which were verified to be transcribed during appropriate life-cycle stages. We also provide data indicating that it is likely that old Mycobacterium bovis bacillus Calmette-Guérin cultures form spores. Together, our data show sporulation as a lifestyle adapted by mycobacteria under stress and tempt us to suggest this as a possible mechanism for dormancy and/or persistent infection. If so, this might lead to new prophylactic strategies.
Ghosh
Jaydip
J
Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Uppsala SE-751 24, Sweden.
Larsson
Pontus
P
Singh
Bhupender
B
Pettersson
B M Fredrik
BM
Islam
Nurul M
NM
Sarkar
Sailendra Nath
SN
Dasgupta
Santanu
S
Kirsebom
Leif A
LA
D004269:DNA, Bacterial / Q000378:metabolism; D005434:Flow Cytometry; D015964:Gene Expression Regulation, Bacterial; D018507:Gene Expression Regulation, Developmental; D006358:Hot Temperature; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D019910:Mycobacterium marinum / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D009693:Nucleic Acid Hybridization / Q000379:methods; D010848:Picolinic Acids / Q000378:metabolism; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D013171:Spores, Bacterial / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure
D004269:DNA, Bacterial; D010848:Picolinic Acids; D012329:RNA, Bacterial; C004860:dipicolinic acid