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Results for “TUBERCLE BACILLI”

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At least 19 recordsLinked to original sources
PubMed1974

Role of mycobactin in the growth and virulence of tubercle bacilli.

Tubercle bacilli failed to grow in iron-void media enriched with solutions of iron-containing transferrin (Tr) or ferritin (F) because these substances do not provide the bacilli with iron, which is essential for their growth. Animal serum and macrophages possessed no iron carrier with an ability to satisfy the need of the bacteria for the metal. Mycobactin (M), the growth-product of tubercle bacilli, removed iron from Tr and F and supplied the metal for bacillary utilization. The role of M in the growth of tubercle bacilli was influenced by nonionic surfactants which inhibited bacillary growth by removing M from the bacillary cells and interfering with the absorption of M-iron complexes. Experiments with Tween 80, Triton WR-1339, and lecithin showed that avirulent bacilli lose M at lower concentrations of the surfactants than virulent bacilli. Since avirulent and virulent bacilli possess the same amount of M, these findings indicate that M is bound more firmly to lipid-rich virulent than lipid-poor avirulent cells. These findings indicate that the resistance of virulent bacilli to the M-removing activity of the surfactants is an indicator of their ability to multiply in the infected host and may be used as a measure of bacillary virulence.

Bacteriological Techniques↗
PubMed1956

Studies on the interaction between phagocytes and tubercle bacilli. II. The action of phagocytes upon C14-labelled tubercle bacilli.

Tubercle bacilli labelled with C(14) were prepared by growth on radioactive substrates such as glycerol, CO(2), and acetate. These organisms were exposed in vitro to leucocytes (mostly polymorphonuclear leucocytes) from peritoneal exudates of guinea pigs. The respiration of the leucocytes and of the bacilli, alone and together, was followed by determining oxygen uptake and C(14)O(2) production. When heat-killed labelled tubercle bacilli were exposed to leucocytes there was little or no degradation of bacillary material to C(14)O(2) by leucocytic enzymes. On the other hand, conversion of components of sonically disrupted bacilli to C(14)O(2) by leucocytes was significant. It was possible to determine the oxygen uptake and C(14)O(2) production of phagocytized living tubercle bacilli, and it was found that after phagocytosis the bacilli maintained their rates of oxygen consumption and C(14)O(2) production. This finding was in contrast to observations made with Mycobacterium phlei, a saprophytic acid-fast organism, and with Bacillus subtilis. In these cases oxygen consumption and C(14)O(2) production declined after phagocytosis, and bacterial components were converted to carbon dioxide to a significant degree by leucocytic enzymes.

Animals↗
PubMed1957

Studies on the interaction between phagocytes and tubercle bacilli. III. Some metabolic effects in guinea pigs associated with infection with tubercle bacilli.

In continuing studies concerning the interactions between phagocytes and tubercle bacilli the effect of tuberculous infection on respiration and glucose utilization was investigated in guinea pigs. Peritoneal exudates rich in polymorphonuclear leucocytes, derived from guinea pigs infected with tubercle bacilli, had a significantly higher rate of respiration than the same cells from normal animals. The difference between cells from normal and infected animals was greater when the animals were infected with a virulent strain (Vallée) than when infected with an attenuated one (R1Rv or BCG). By the use of glucose labelled with C(14) at position 1 or 6, or uniformly labelled glucose, it was established that this difference in oxygen uptake between normal and infected cells was probably not caused by a difference in the pathway of glucose utilization. Similarly, the respiration of liver and kidney slices from normal and infected guinea pigs was compared and it was found that liver slices showed differences similar to those shown by leucocytes, but that the kidney slices did not. The possibility has not been ruled out that the difference in rate of respiration of liver slices due to infection might be caused by tuberculous lesions in the livers of infected animals. The mononuclear cells which invade the liver have a higher rate of oxygen uptake than liver cells. The rate of glucose utilization and the total amount of CO(2) produced was also determined in intact guinea pigs. Both functions were found not to differ significantly in normal and infected animals. The rate of production of CO(2) from C(1) and C(6) of glucose was the same in both groups of animals. The ratio of the rate of production of C(14)O(2) from C(1) and C(6) of glucose by the whole animal was found to be about 1.35. It was found to be much higher with polymorphonuclear leucocytes (C(1)/C(6) = 8 in the absence of serum). During the process of phagocytosis this ratio increased from about 25 to about 130 (in the presence of 2 per cent serum) indicating an increase in the direct oxidative pathway of glucose utilization during stimulated cellular activity.

Animals↗
PubMed1961

The virulence in the guinea-pig of tubercle bacilli isolated before treatment from South Indian patients with pulmonary tuberculosis. 2. Comparison with virulence of tubercle bacilli from British patients.

A series of studies has been undertaken by the Tuberculosis Chemotherapy Centre Madras, with the ultimate object of finding out whether differences in the virulence of the tubercle bacilli isolated from Indian tuberculous patients before the start of chemotherapy are related to the severity of the patients' disease and to the subsequent response to treatment. This paper-the second in the series-presents the results of a comparative investigation of the virulence in the guinea-pig of tubercle bacilli obtained from Indian and from British tuberculous patients before treatment. In this investigation, which was carried out at the Centre and at the Microbiological Research Establishment, Porton, England, the virulence of the Indian and the British cultures was assessed by guinea-pig mortality, by the "root-index of virulence" (based on the post-mortem tuberculous disease score and the survival period of the animal), and by the results of spleen culture. The Indian cultures were found, on the average, to be less virulent and to show a w der range of virulence than the British cultures, both in the Porton and in the Madras series of experiments. A further indication of the heterogeneity of the Indian tubercle bacilli was provided by the results of tuberculin tests: whereas the British cultures appeared to be homogeneous in their ability to induce tuberculin allergy in the guinea-pig, the Indian cultures showed considerable variation in this respect.

Animals↗