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M Ishaque

Publications and source records attributed to M Ishaque.

68 records · Page 4Linked to original sources
PubMedDate not supplied

[Energy production in Mycobacterium lepraemurium cultured in vitro].

Cell-free extracts prepared from in vitro cultured Mycobacterium lepraemurium catalysed phosphorylation coupled to the oxidation of NADH and succinate, yielding P/O ratios of 0.52 and 0.34, respectively. No ATP synthesis occurred during oxidation of ascorbate. Oxidative phosphorylation was uncoupled by dinitrophenol and dibromophenol. Oxidation of NADH and coupled phosphorylation was markedly inhibited by rotenone, whereas this inhibitor had no effect on succinate oxidation and associated ATP synthesis. Oxidative phosphorylations and coupled oxidations of NADH and succinate were strongly inhibited by antimycin A and cyanide.

Adenosine Triphosphate↗
PubMedDate not supplied

Separation of Mycobacterium lepraemurium from the subcutaneous tissues of the rat.

In an effort to obtain cell suspensions free from blood cells which interfere in spectrophotometric studies, a method was devised by which relatively large quantities of whole cell suspensions of M. lepraemurium are obtained for experimental purposes. We have routinely employed this procedure which is quite reliable, technically simple, moderate in equipment requirements, and in a matter of five minutes it can be ascertained whether or not the preparations are free from contaminants which render the purified bacillary suspensions unsuitable for studies involving spectrophotometric technics. However, in this procedure, certain points are essential in order to obtain large quantities of purified bacillary suspensions. It is important to homogenize the lepromata for only a few seconds at brief intervals. Excessive homogenization may cause considerable damage to the bacilli and it may be difficult to separate the bacilli from the host tissues. It is also important to use transparent bottles and tubes during centrifugation as the material can be seen and thus each fraction can be separated easily. Very few bacilli are lost in the discarded material and we have repeatedly obtained 2.5 to 3 gm wet weight of M. lepraemurium from one leproma weighing 25 gm to 30 gm.

Animals↗
PubMedDate not supplied

Cytochrome-linked respiration in host grown M. leprae isolated from an Armadillo (Dasypus novemcinctus, L.).

The bacilli were isolated from an armadillo (Dasypus novemcinctus, L.) and cytochrome systems as well as oxidation of succinate and NADH by M. leprae were studied. Cell-free extracts of M. leprae contained cytochromes of the a + a3, b, c and o type. Whole cell suspensions catalyzed the oxidation of succinate. The process was unaffected by rotenone but was markedly inhibited by thenoyltrifluoroacetone, antimycin A and cyanide. Cell-free preparations of M. leprae also oxidized NADH with oxygen as the terminal electron acceptor. Although NADH oxidation was completely inhibited by rotenone, the process was inhibited to only 50% by 5 millimols cyanide. The results indicated that complete respiratory system is present in M. leprae isolated from leprous tissues of an armadillo. The effect of inhibitors on succinate and NADH oxidations showed that the respiration in host-grown M. leprae is mediated through the cytochrome system with oxygen as the final electron acceptor.

Animals↗
PubMedDate not supplied

In vitro cultivation of mycobacteria in cholesterol lecithin media from lepromas of rats infected with Mycobacterium lepraemurium.

In vivo grown M. lepraemurium suspensions were inoculated into a basal medium containing cholesterol and lecithin. Slow growing strains of mycobacteria were cultured regularly in these media. The presence of free cholesterol or cholesterol in serum or cholesterol in trypsin-digested egg yolk was essential for growth. The primary cultures were difficult to obtain, but the strains were easily subcultured. A heavy inoculum was necessary to obtain primary cultures in the liquid media, no growth occurred on semisolid agar slants. Similarly slow-growing primary cultures were obtained on Ogawa egg yolk media. Growth developed in a considerably shorter time if Ogawa's medium was enriched with 0.4% yeast extract (Difco). The cultures obtained on Ogawa egg yolk media were successfully subcultered in liquid cholesterol-lecithin media. The relation of the cultured strains of mycobacteria to the pathology of murine leprosy is not yet clear. The dynamics of cholesterol metabolism in the macrophages related to murine leprosy is discussed.

Animals↗
PubMedDate not supplied

A simplified hyaluronic acid based culture medium for mycobacteria isolated from human lepromata.

Acid-fast bacilli multiplied in liquid culture media containing hyaluronic acid when inoculated with mycobacteria from a lepromatous leprosy nodule. The culture was readily subcultured at ten day intervals in the homologue media, but failed to grow in the Dubos, Middlebrook and Lowenstein media. These findings confirm the results of Skinsnes et al (1975). Identification of this culture is not yet available, however it gives positive immunofluorescence with authentic anti-M. leprae serum. The obtained culture also grows as a chromogenic culture at 34 degrees C on a simple medium prepared from trypsin digested human umbilical cord, yeast extract powder and glycerol. This medium can be sterilized in an autoclave, but filter sterilized sheep, bovine or horse serum must be added aseptically as an essential ingredient. The medium does not differ considerably from the hyaluronic acid medium proposed by Skinsnes et al, but it is easier to prepare, it is inexpensive and permits a logarithmic growth within seven days of the so far unidentified culture isolated from leprotic nodules.

Cell Division↗
PubMedDate not supplied

Oxidation of 3,4-dihydroxyphenylalanine by connective tissue constituents. Identification of Mycobacterium leprae not related to phenolase activity.

The oxidation of 3,4-dihydroxyphenylalanine (DOPA) was studied by spectrophotometric methods at pH 6.8. In the presence of L- or D-DOPA, a color development occurred in the presence of the following substances as measured by increase in absorption both at 540 nm and 480 nm: hyaluronic acid, trypsinized human skin and umbilical cord extract, trypsin treated rat tissue from subcutaneous rat leproma, trypsin treated M. lepraemurium isolated from rat lepromata, and trypsinized M. leprae isolated from non-treated lepromatous leprosy cases. Normal human skin and connective tissue extract and nontrypsinized connective tissue of rat leprosy granuloma did not oxidize DOPA. While the trypsin-treated partially purified M. leprae suspension oxidized DOPA at both wave-lengths, the hyaluronidase-treated same suspension of M. leprae failed to oxidize these phenolic compounds. Mushroom tyrosinase oxidized D-DOPA, L-DOPA, epinephrine and norepinephrine at 480 nm. Hyaluronic acid also oxidized epinephrine and norepinephrine at both wave-lengths. Since it is known that M. leprae in the human host is closely associated with the presence of the acid mucopolysaccharides of the skin, and since acid mucopolysaccharides and skin constituents strongly oxidized DOPA, and since the hyaluronidase treated M. leprae failed to oxidize DOPA, it became evident that hyaluronic acid and not M. leprae is responsible for DOPA oxidation, and phenolase activity is not associated with the metabolism of M. leprae. Evidence is presented that DOPA is not a unique characteristic of the human leprosy bacillus. For instance, trypsin-treated murine leprosy bacilli from the rat strongly oxidized DOPA. The reaction of DOPA oxidation, therefore, must be rejected as a test for the identification of M. leprae. The obtained results confirmed the pertinent findings of Skinsnes and his co-workers.

Animals↗