RESUMO
MICs of ciprofloxacin, sparfloxacin, ofloxacin, amikacin and rifampicin were determined for 14 primary clinical isolates and three reference isolates of Mycobacterium ulcerans by modifying a standard agar dilution method for testing Mycobacterium tuberculosis sensitivity. All these antimicrobials were active against every isolate of M. ulcerans. Sparfloxacin exhibited the highest activity and ofloxacin was the least effective. Rifampicin exhibited the broadest range of activity.
Assuntos
Amicacina/farmacologia , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Hansenostáticos/farmacologia , Mycobacterium ulcerans/efeitos dos fármacos , Rifampina/farmacologia , Fluoroquinolonas , Humanos , Testes de Sensibilidade Microbiana , Infecções por Mycobacterium não Tuberculosas/microbiologia , UgandaRESUMO
Protein introns are recently discovered genetic elements whose intervening sequences are removed from a precursor protein by an unusual protein splicing reaction. This involves the excision of a central spacer molecule, the protein intron, and the religation of the amino- and carboxy-terminal fragments of the precursor. The recA gene of Mycobacterium tuberculosis contains one such element and we now show that the other major mycobacterial pathogen, Mycobacterium leprae, also possesses a protein intron in its recA, although other mycobacterial recA genes do not. However, these two protein introns are different in size, sequence and location of insertion of their coding sequences into the recAs of M. tuberculosis and M. leprae, indicating that acquisition of the protein introns has occurred independently in the two species, and thus suggesting that there has been selection for splicing in the maturation of RecA in the pathogenic mycobacteria. The M. leprae protein intron provides an example of conditional protein splicing, splicing occurring in M. leprae itself but not when expressed in Escherichia coli, unlike most previously described protein introns. These observations suggest that protein introns may perform a function for their host, rather than being just selfish elements.
Assuntos
Íntrons , Mycobacterium leprae/genética , Mycobacterium tuberculosis/genética , Recombinases Rec A/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , DNA Bacteriano , Dados de Sequência Molecular , Splicing de RNA , RNA Bacteriano , Homologia de Sequência de AminoácidosRESUMO
The gene encoding a major 28-kilodalton antigen of Mycobacterium leprae has now been sequenced and identified as the enzyme superoxide dismutase (SOD) on the basis of the high degree of homology with known SOD sequences. The deduced amino acid sequence shows 67% homology with a human manganese-utilizing SOD and 55% homology with the Escherichia coli manganese-utilizing enzyme. The gene is not expressed from its own promoter in E. coli but is expressed from its own promoter in Mycobacterium smegmatis. The amino acid sequences of epitopes recognized by monoclonal antibodies against the 28-kilodalton antigen have been determined.