RESUMO
Two strains of a novel aerobic, bacteriochlorophyll a-containing species of the alpha-4 subclass of the Proteobacteria were isolated from the hot spring at Alcafache in central Portugal. 16S rRNA gene sequence-based phylogenetic analyses showed the two novel isolates to be phylogenetically related to members of the genera Erythrobacter, Erythromicrobium and Porphyrobacter. The strains produce reddish-orange-pigmented colonies, have an optimum growth temperature of about 50 degrees C and could be distinguished from the species Porphyrobacter tepidarius, which also has a high growth temperature, primarily on the basis of the fatty acid composition. The novel species does not grow anaerobically in the presence or absence of a light source. The strains of the novel species utilize several single carbon sources for growth, most of which are also used by P. tepidarius. The species status of strains ALC-2T and ALC-3 was confirmed by low reassociation values of the DNA with species of the genera Erythrobacter, Erythromicrobium and Porphyrobacter. Phenotypic characteristics and 16S rRNA gene sequence analyses also show that strains ALC-2T (=DSM 12079T =ATCC BAA-386T) and ALC-3 (=DSM 12080) represent a novel species, for which the name Porphyrobacter cryptus sp. nov. is proposed.
Assuntos
Alphaproteobacteria/classificação , Aerobiose , Alphaproteobacteria/genética , Alphaproteobacteria/isolamento & purificação , Alphaproteobacteria/metabolismo , Bacterioclorofila A/metabolismo , Composição de Bases , Brasil , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/genética , Ácidos Graxos/análise , Genes Bacterianos , Temperatura Alta , Lipídeos/análise , Microscopia Eletrônica , Dados de Sequência Molecular , Filogenia , Quinonas/análise , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Microbiologia da ÁguaAssuntos
Hanseníase Virchowiana/imunologia , Imuno-Histoquímica , Lactoferrina/imunologia , Mycobacterium leprae/imunologia , Mycobacterium leprae/metabolismo , Mycobacterium leprae/ultraestrutura , Mycobacterium tuberculosis/imunologia , Mycobacterium tuberculosis/ultraestrutura , Pele , Pele/imunologia , Proteínas de Choque Térmico/imunologia , Western BlottingRESUMO
In previous reports on the ultrastructure of Mycobacterium leprae, we described the occurrence of symmetric membranes in normal-looking bacilli from fresh or frozen samples primarily fixed with aldehydes. In those reports we admitted that such a symmetric profile, which is not found in the other normal mycobacteria, would not represent the structure of the normal membrane of the leprosy bacillus. We, therefore, re-analyzed the ultrastructure of the membrane of M. leprae. In the present work the micromorphology of the M. leprae membrane was studied by transmission electronmicroscopy after the fixation of fresh samples by OsO4 plus calcium followed by glutaraldehyde plus formaldehyde and calcium followed by uranyl acetate. The study of samples from two patients with lepromatous (LL) leprosy, three armadillos with natural leprosy, and one nude mouse with experimental leprosy showed that normal-looking bacilli present in lead-stained sections had asymmetric membranes with a thickness of 6.49 +/- 0.36 nm. These membranes showed periodic acid-Schiff (PAS)-positive components exclusively located in the outer half of the bilayer. We demonstrated that the symmetric profile of the M. leprae membrane described in our previous reports corresponds, as admitted in those reports, to an abnormal membrane structure. Such an abnormality was now found to result from the use of primary fixation with aldehydes or of samples stored frozen before fixation. These results indicate that, although ultrastructurally similar to that of the other mycobacteria, the membrane of M. leprae has a peculiar sensitivity to fixation by aldehydes. Such a characteristic, which was not found in M. lepraemurium, M. aurum, M. avium, and M. tuberculosis H37Ra, must reflect a unique membrane molecular structure, which is presently unknown