Involvement of caspase-9 in the inhibition of necrosis of RAW 264 cells infected with Mycobacterium tuberculosis.

In order to know how caspases contribute to the intracellular fate of Mycobacterium tuberculosis and host cell death in the infected macrophages, we examined the effect of benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethane (z-VAD-fmk), a broad-spectrum caspase inhibitor, on the growth of M. tuberculosis H37Rv in RAW 264 cells. In the cells treated with z-VAD-fmk, activation of caspase-8, caspase-3/7, and caspase-9 was clearly suppressed, and DNA fragmentation of the infected cells was also reduced.

Streptomycin-dependent exhibition of cytokine-inducing activity in streptomycin-dependent Mycobacterium tuberculosis strain 18b.

Peritoneal exudate cells of mice were stimulated with a streptomycin-dependent Mycobacterium tuberculosis strain, 18b. Gamma interferon production by natural killer cells depending on interleukin-12 and interleukin-18 was induced only in the presence of a high dose of streptomycin. This study suggested the requirement of active bacterial metabolism for this host response.

[Comparison between relative analogy and homology of 16S rRNA partial sequences between Mycobacterium szulgai and Mycobacterium malmoense].

A lot of nucleotide sequences of some genes, especially 16S rRNA gene, are registered in the public data-base. In order to identify clinical mycobacterial strains, 16S rRNA gene partial nucleotide sequences from 15 strains of Mycobacterium malmoense and 24 strains of Mycobacterium szulgai which are stored in the Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association were determined. Then homology of the sequences to the data of type strains submitted to public database were determined.

[Relative relatedness of 11 mycobacteria species by microplate hybridization methods considering delta Tm].

Intra-species variance within Mycobacterium xenopi, Mycobacterium gordonae or Mycobacterium szulgai has been reported in identification employing chemotaxonomic characteristics, 16 S rRNA gene sequences or relative relatedness (relative color index) of genomic DNA-DNA Hybridization. Genomic DNA-DNA reassociation at the constant temperature was found to be unreliable for classification of mycobacterial species. However, nonspecific DNA reassociation could be avoided by hybridization at 56 degrees C after 45 degrees C overnight, and this technique was named delta DDH method in the preceding paper.

[Microplate hybridization methods of reduced unspecific reassociation considering delta Tm--comparison between relative relatedness of DNA and key characters for Mycobacterium szulgai].

It has been recognized that colorimetric microdilution plate hybridization method (DDH) shows equivocal identification results for some strains of Mycobacterium gordonae, and that chemotaxonomic identification method reveals some intermediate pattern between Mycobacterium szulgai and M. gordonae. In the present study, the results obtained by chemotaxonomic identification method on 25 strains of M.