Sporulation in mycobacteria

Abstract

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-Gué rin 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.Mycobacterium marinum ͉ cell division ͉ DNA replication ͉ cell cycle ͉ endosporulation

Cloning and Expression of FixA and FixB Genes and Their Role in the Formation of Dipicolinic Acid in Mycobacterium marinum CCUG 20988

“…This finding opens up a new hitherto to the unknown area of high G+C percent of Gram positive bacteria such as Mycobacteria. This finding is consistent with Ghosh et al [7]. They could detect dipicolinic acid in M. marinum cells of different ages using colorimetric assay method suggested by Janssen et al [10].…”

“…Also, they showed that whole-cell extract of C. perfringenes NCTC 8679, a strain shown to produce spore with significant amount of DPA, indicated that DPA synthase activity in this strain was greatest 11 hours after inoculation into DSSM medium. Based on the work provided by Ghosh et al [7] and presence of some evidence in sporulation in laboratory cultures of the mycobacterial strain such as M. marinum, M. bovis bacillus Calmette-Guerin strain, finding new evidences to support this claim is important.…”

“…The genus Mycobacterium includes highly successful pathogens such as Mycobacterium tuberculosis and Mycobacterium leprae, the etiological agents of tuberculosis and leprosy [7]. Recently, Ghosh et al reported that species of M. marinum produce a type of spore known as endospore.…”

“…This discovery is potentially significant in medicine, because it is a definition for latency paradigm in Mycobacterium genus. M. marinum is a close genetic relative of M. tuberculosis, and it has emerged as an attractive model system to identify and study factors important for infection disease development and resistance of M. tuberculosis [7].…”

Thermal Resistance of Mycobacterium Avium Subsp. Paratuberculosis

“…W starszych kulturach Mycobacterium marinum i M. bovis BCG stwierdzono występowanie przetrwalników, a jednocześnie -podobnych w przebiegu krzywych inaktywacji cieplnej w czasie ogrzewania w temp. 65 ºC/15 min, jakie obserwuje się w przypadku Map [9]. Hipoteza, że Map w warunkach niesprzyjających (np.…”