A search for the genotoxic principle associated with the tubercule bacillus, Mycobacterium tuberculosis using mice as model

G. K. Manna, S. Pal
The genotoxic potentiality of some nonpathogenic and pathogenic species of lower group of bacteria was almost exclusively reported by Manna and his collaborators which has been reviewed by him from time to time (Manna 1973 (Manna , 1980(Manna , 1986(Manna , 1989. Recently the present authors (Manna and Pal 1989) discovered the mutagenic potentiality of the log culture of tubercule bacillus, Mycobacterium tuberculosis in experimentally injected mice by more than one mutagenicity test as
more » ... ty test as recommended (Bochkov et al. 1976 ) , like bone marrow chromosome aberrations and micronucleus test in both sexes and germinal chromosome aberrations and sperm with abnormal head morphology in treated males . However, with a view to finding out the factor which could possibly be associated with the bacterium, M . tuberculosis for inducing the genotoxic effect in mice has specially been investigated here. The bone marrow chromosome aberration frequency data in separate sets of mice treated with various samples of M. tuberculosis and the BCG vaccine have been used as the indicator of the potentiality of the genotoxic principle against controls. Materials and methods Inbred laboratory stock of Swiss albino mice, Mus musculus was used. Two male and two female specimens in each set of treated and control were individually injected intraperi toneally with different samples as follows at the rate of 1ml per 100gm body weight of indi vidual specimen and the effect in the bone marrow cells was assessed on 7th day after injection. Preparation of samples for injection A. Treated series (Tr. 1. Log. cul.) Log culture of Mycobacterium tuberculosis. The pure sample of the bacterium obtained through the courtesy of Dr. A. N. Chakraborty, Department of Pathology, S. S. K. M. Hospital, Calcutta was subcultured in freshly prepared Kirschner's medium which attained the log phase of growth on 7th day of incubation. (Tr. 2. Cul. fil.) Culture filtrate. 10ml of log culture of M. tuberculosis was centrifused at 10,000r. p. m. for 10min. The supernatant was gently decanted to another tube and filtered through Sinter's glass filter to remove complete trace of bacterium. The process was repeated to be absolutely sure which was confirmed by culturing a part of the filtrate in sterile medium showing no growth of bacteria. The sample was then injected. (Tr. 3. Iso. bac.) Isolated M. tuberculosis suspended in saline. 10ml of log culture of M. tuberculosis was centrifused at 10,000 r. p. m. for 10min and the supernatant was discarded. The residual part was mixed with 0.85% normal saline to make the volume of 10ml again and then centrifused. The supernatant was discarded and the residual part was mixed again with normal saline to make the volume of 10 ml. The process was repeated 3 or 4 times so as to remove the trace of culture medium completely. The sample was then injected into mice
doi:10.1508/cytologia.55.381 fatcat:xwl6otmhgndmpkbqfvsemvyhgq