Use of an ordered cosmid library to deduce the genomic organization of <i>Mycobacterium leprae</i>

Eiglmeier, Karin; Honoré, Nadine; Woods, Sally A.; Caudron, Bernard; Cole, Stewart T.

doi:10.1111/j.1365-2958.1993.tb01111.x

Cited by 118 publications

(56 citation statements)

References 45 publications

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“…Upon analyzing the genome sequences, a putative ppGpp synthase has been identified in M. tuberculosis (7) and Mycobacterium leprae (11). Interestingly, the single gene identified has almost 50% homology to both relA and spoT (encoding ppGpp hydrolase) of E. coli.…”

Section: Resultsmentioning

confidence: 99%

High Intracellular Level of Guanosine Tetraphosphate in Mycobacterium smegmatis Changes the Morphology of the Bacterium

2000

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Almost one-third of the world population today harbors the tubercle bacillus asymptomatically. It is postulated that the morphology and staining pattern of the long-term persistors are different from those of actively growing culture. Interestingly, it has been found that the morphology and staining pattern of the starved in vitro population of mycobacteria is similar to the persistors obtained from the lung lesions. In order to delineate the biochemical characteristics of starved mycobacteria, Mycobacteria smegmatis was grown in 0.2% glucose as a sole carbon source along with an enriched culture in 2% glucose. Accumulation of the stringent factor guanosine tetraphosphate (ppGpp) with a concomitant change in morphology was observed for M. smegmatis under carbon-deprived conditions. In addition, M. smegmatis assumed a coccoid morphology when ppGpp was ectopically produced by overexpressing Escherichia coli relA, even in an enriched medium. The Mycobacterium tuberculosis relA and spoT homologue, when induced in M. smegmatis, also resulted in the overproduction of ppGpp with a change in the bacterium's growth characteristics.Mycobacteria have emerged as a major threat to humankind, for as many as one-third of the world's population (1.7 billion) harbors the tubercle bacillus asymptomatically (18). The latent bacilli can persist in a somewhat ill-defined physiological state in pulmonary and extrapulmonary lesions for years after infection (30). These bacilli are opportunistic and can reactivate themselves when the host is immunocompromised. To add to the misery, persistors require prolonged therapy, and Mycobacterium bovis BCG vaccination has little effect in blocking reactivation of the bacteria. Hence, for improved control of tuberculosis, it is imperative to develop effective drugs to cease the propagation and persistence of these latent bacilli. This will be greatly facilitated by a better understanding of the physiological state of these latent bacteria. Although several in vitro models suggest low extracellular concentrations of oxygen to be an important cause for mycobacterial dormancy (8,10,42), the effect of this state on cellular metabolism is not clear.It has been shown that the morphology and staining pattern of an in vitro culture of mycobacteria differ from those of persistors which are obtained from the lung lesion and are chromophobic to the conventional acid-fast staining (25, 26). The former is an acid-fast and long rod-shaped bacillus, as opposed to the latter, which is non-acid fast and granular. However, these persistors can be stained after oxidizing the cell surface with periodic acid. In yet another important observation, it has been shown that the morphology and staining pattern of such persistors can be obtained in vitro by starving the Mycobacterium tuberculosis, Mycobacterium kansasii, or Mycobacterium pheli cultures on agar plates without any nutrients (26). This key observation suggests that the natural persistors may be physiologically similar to bacteria in nutritionally starved cultu...

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Section: Resultsmentioning

confidence: 99%

High Intracellular Level of Guanosine Tetraphosphate in Mycobacterium smegmatis Changes the Morphology of the Bacterium

2000

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“…In M. leprae, all these phosphate transport genes were found in two different non-adjacent cosmids: B1308 for pstB, pstS-1, pstC-1, pstA-2 and pstS-2 and B650 [39] for pstS-3, pstC-2 and pstA-1 (Fig. 1).…”

Section: Discussionmentioning

confidence: 99%

“…1). Moreover, one additional M. leprae cosmid, cosmid B2266 [39], contains genes coding for phoS, phoW, phoX, phoT and phoY proteins homologous to E. coli PstS, PstC, PstA, PstB and PhoU proteins, respectively. Therefore it is conceivable that genes coding for a fourth phosphate transport permease are also present in the M. tuberculosis genome.…”

Section: Discussionmentioning

confidence: 99%

Identification of a second Mycobacterium tuberculosis gene cluster encoding proteins of an ABC phosphate transporter

et al. 1996

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Following the identification of a M. tuberculosis phosphate transporter belonging to the superfamily of ABC transporters, we report on the cloning and sequencing of two additional genes, called pstS-3 and pstC-2, encoding proteins homologous to PstS and PstC of Escherichia coli, respectively. Together with the previously isolated M. tuberculosis gene similar to the E. coli pstA, these are included in a cluster encoding a second putative phosphate transport system. We demonstrate that pstS-3 encodes the previously described Ag 88, a 40 kDa M. bovis BCG culture filtrate antigen (immunodominant in H-2 b haplotype type mice). Finally, a signature motif identifying integral transmembrane proteins of prokaryotic phosphate binding-dependent permeases is proposed.

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“…The four Calymmin prodomains exhibit different degrees of homology to portions of the amino acid sequence of some polypeptides from the databases with unknown functions. These peptides included the Drosophila melanogaster cg6639, a serine protease-like peptide, and cg11581 proteins (Adams et al, 2000), and the Mycobacterium tuberculosis hypothetical 56.9-kDa protein cy10h4.20c (Cole et al, 1998), and the M. leprae hypothetical 49.8-kDa protein (Eiglmeier, et al, 1993), both of which also contain forkhead-associated domains (Durocher et al, 1999) at their C terminus ( Fig. 2A).…”

Section: Isolation Of Calymmin Full-length Cdna and Amino Acid Sequenmentioning

confidence: 99%

Molecular characterization of Calymmin, a novel notochord sheath‐associated extracellular matrix protein in the zebrafish embryo

Cerdà

Gründ

Franke

et al. 2002

Developmental Dynamics

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During the screening of a zebrafish postsomitogenesis embryo cDNA library, we have identified a cDNA corresponding to a novel type of protein localized to the notochordal sheath-associated extracellular matrix (ECM) of the embryo. The 4.049-kb mRNA encodes a predicted polypeptide of 1,207 amino acids (122 kDa, pI 10.50) with a potential signal peptide of 20 amino acids. After the signal peptide, the mature protein consists of 1,187 amino acids (119 kDa, pI 10.46), for which the name "Calymmin" (from Greek ␣ ␣, to envelop, to cover) is proposed. The Calymmin mRNA is highly and transiently expressed by the notochord cells of the embryo from the 10-to 12-somite stage to the pharyngula period (13 and 24 hours postfertilization, respectively), and light and electron microscopical immunolocalization analysis revealed that the protein was specifically localized within a granular and filamentous layer of the ECM compartment surrounding the notochord. In zebrafish no tail mutants (ntl tc41 ), in which the notochord precursor cells are present but fail to differentiate, the Calymmin protein was not detected, confirming the notochord origin of Calymmin. These results indicate that Calymmin is a novel constitutive protein of the ECM compartment associated to the perinotochordal sheath in the zebrafish embryo, which is specifically expressed by the differentiating notochord cells.

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Use of an ordered cosmid library to deduce the genomic organization of Mycobacterium leprae

Cited by 118 publications

References 45 publications

High Intracellular Level of Guanosine Tetraphosphate in Mycobacterium smegmatis Changes the Morphology of the Bacterium

High Intracellular Level of Guanosine Tetraphosphate in Mycobacterium smegmatis Changes the Morphology of the Bacterium

Identification of a second Mycobacterium tuberculosis gene cluster encoding proteins of an ABC phosphate transporter

Molecular characterization of Calymmin, a novel notochord sheath‐associated extracellular matrix protein in the zebrafish embryo

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