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Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Guinea pigs immunized with the hapten 2,4-dinitrophenyl (DNP) coupled directly to Mycobacterium tuberculosis of strain H37Ra (DNP-H37) show a variety of cell-mediated immune responses to DNP coupled to protein carriers. The cells responsible for this specific response are thought to be T lymphocytes for the following reasons: Guinea pigs immunized with DNP-H37 displayed delayed hypersensitivity reactions to several DNP-proteins and contact sensitivity to dinitrofluorobenzene. Peritoneal exudate lymphocytes (PELs) obtained from DNP-H37 immune animals respond to DNP-proteins with DNA systhesis and cause inhibition of macrophage migration. PELs are highly enriched in T lymphocytes and contain few immunoglobulin-bearing cells. Further depletion of immunoglobulin-bearing cells from this population does not diminish the in vitro proliferative response to antigen. Nitrophenyl conjugates of proteins lacking a paranitro group stimulated DNA synthesis poorly or not at all, indicating the importance of the paranitro group of DNP in antigen recognition by T cells in this system. In this respect, the specificity of T cells resembles that of DNP-specific antibody from the same animals. On the other hand, DNP conjugates of copolymers of glutamic acid and lysine and DNP conjugated to proteins via an interposed beta-alanyl-glycyl-glycyl spacer failed to stimulate DNA synthesis, although such compounds bind very efficiently to anti-DNP antibody. By contrast, DNP conjugates of synthetic polypeptide carriers containing as little as 7% tyrosine strongly stimulated DNA synthesis in DNP-H37 immune PELs. That the determinant responsible for this stimulation was DNP coupled to the hydroxyl group of tyrosine was shown by selective removal of DNP from tyrosine by thiolysis with 2-mercaptoethanol, which abolished their ability to stimulate T cells.
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PMID:The specificity of cellular immune responses in guinea pigs. I. T cells specific for 2,4-dinitrophenyl-o-tyrosyl residues. 4 12

Menaquinones were the only isoprenoid quinones found in 85 of the 95 coryneform bacteria examined. Dihydromenaquinones having nine isoprene units were the main components isolated from Corynebacterium bovis, from other glutamic acid-producing strains, and from Arthrobacter globiformis and related species. Dihydromenaquinones with eight isoprene units were found in Brevibacterium linens, the remaining Corynebacterium species and strains probably belonging to the genus Rhodococcus. Tetrahydromenaquinones with eight isoprene units were found in Arthrobacter simplex and Arthrobacter tumescens, and with nine isoprene units in Cellulomonas and Oerskovia. Kurthia and Curtobacterium were characterized by menaquinones with seven and nine isoprene units, respectively, and Microbacterium lacticum and Corynebacterium aquaticum had comparable amounts of menaquinones with 10 and 11 isoprene units. Strains received as Brevibacterium leucinophagum, Corynebacterium autotrophicum, Corynebacterium nephridii, Mycobacterium flavum, Mycoplana rubra and Protaminobacter ruber contained uniquinones as their sole isoprenoid quinones. The isoprenoid quinone data correlate well with major trends in coryneform taxonomy and are of value in the classification of coryneform and related bacteria.
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PMID:Isoprenoid quinones in the classification of coryneform and related bacteria. 10 69

Active transport of proline remained unaffected in phospholipase A-treated electron transport particles from Mycobacterium phlei. However, the steady state level of proline was reduced 50 to 60% in phospholipase A-treated depleted electron transport particles that were devoid of membrane-bound coupling factor-latent ATPase activity. The decrease in the uptake of proline in the phospholipase A-treated depleted electron transport particles was not due to a change in the apparent K-m for proline, but it was related to the amount of phospholipid cleaved from the membranes. Restoration in the level of proline transport in phospholipase A-treated depleted electron transport particles was achieved by reconstituting these vesicles with diphosphatidylglycerol and phosphatidylethanolamine liposomes. Diphosphatidylglycerol was found to be most effective in the restoration of proline uptake. In contrast to the effect of phospholipase A treatment on proline transport, similar treatement of the electron transport particles or depleted electron transport particles failed to inhibit the active transport of either glutamine or glutamic acid. Studies with phospholipase A-treated membrane vesicles confirmed earlier findings that a proton gradient is not required for active transport of amino acids.
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PMID:Effect of phospholipase A on active transport of amino acids with membrane vesicles of Mycobacterium phlei. 12 19

On the basis of mutual inhibition of uptake with different amino acids in whole cells of Mycobacterium phlei, it was demonstrated that the binding site of proline was different from those of all other amino acids studied. Other groups of amino acids share a common binding site: lysine, histidine, and arginine; valine, leucine, and isoleucine; tryptophan, tyrosine, and phenylalanine; glutamic acid and aspartic acid. The exit and entry processes were studied for proline, glutamine, and glutamic acid. It was observed that in each case the entry and exit processes were mediated by different membrane sites.
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PMID:Different binding sites for entry and exit of amino acids in whole cells of Mycobacterium phlei. 26 21

The mouse pathogen Mycobacterium lepraemurium is readily phagocytosed by cultured mouse peritoneal macrophages. Ingestion is normally followed by fusion between phagosomes and lysosomes. The influence of some aninonic compounds known to inhibit fusion in other systems was investigated by transmission electron microscopy after ingestion of M. lepraemurium. Fusion was markedly, although temporarily, inhibited by suramin and moderately inhibited by poly-D-glutamic acid. The effects are, however, not sufficient to permit these agents to be used to study the long-term effects of shutting off the secondary lysosome-phagosome fusion system in cultured macrophages infected with M. lepraemurium.
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PMID:Effects of anionic inhibitors of phagosome-lysosome fusion in cultured macrophages when the ingested organism is Mycobacterium lepraemurium. 37 57

Membrane vesicles from Mycobacterium phlei contain carrier proteins for proline, glutamine, and glutamic acid. The transport of proline is Na+ dependent and required substrate oxidation. A proline carrier protein was solubilized from the membrane vesicles by treatment with cholate and Triton X-100. Electron microscopic observation of the detergent-treated membrane vesicles showed that they are closed structures. The detergent-extracted proteins were purified by means of sucrose density gradient centrifugation, followed by gel filtration and isoelectric focusing. A single protein with a molecular weight of 20,000 +/- 1000 was found on polyacrylamide gel electrophoresis. Reconstitution of proline transport was demonstrated when the purified protein was incubated with the detergent-extracted membrane vesicles. This reconstituted transport system was specific for proline and required substrate oxidation and Na+. The purified protein was also incorporated into liposomes, and proline uptake was demonstrated when energy was supplied as a membrane potential introduced by K+ diffusion via valinomycin. The uptake of proline was Na+ dependent and was inhibited by uncoupler or by sulfhydryl reagents.
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PMID:Isolation, purification, and reconstitution of a proline carrier protein from Mycobacterium phlei. 44 50

Mycobacterium smegmatis, its orange-red--pigmented (OR) variants, and back mutant strains were examined by electron microscopy using ultrathin sectioning, negative or positive staining, and freeze-fracture-etching methods. The parental and back mutant strains showed almost identical ultrastructures. Specifically, thick ramified fibers measuring about 15 nm in diameter were always visible in the positively stained cell wall, although they were not readily visualized with negative staining or freeze-fracture-etching. In contrast, the cell walls of OR variants contained fibrous networks measuring about 11 nm in diameter, which could be observed by positive and negative staining as well as freeze-fracture-etching. Although cytoplasmic structures appeared similar among the four strains examined, mesosomes were significantly more abundant in the OR variants. The basal layer of the cell wall obtained as a phenol residue consisted of a dense membranous matrix containing scattered fibrous structures in the parental and back mutant strains, and fibrous networks in the OR variants. Chemical analyses showed that the basal layers of all four strains contained the same neutral sugars, amino sugars, and amino acids, i.e., arabinose, galactose, muramic acid, glucosamine, alanine, glutamic acid, and diaminopimelic acid. The alpha-branched, beta-hydroxylated fatty acids contained in the basal layers differ among the four strains, however, with nocardomycolic acids being present in the OR variants and mycolic acids in the parental and back mutant strains. Our previous conclusion that OR variants of M. smegmatis have characteristics similar to those of nocardia is supported by the present study.
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PMID:Ultrastructure of Nocardia-like variants of Mycobacterium smegmatis and chemical composition of the basal cell wall layer. 59 95

Mycobacterium avium has a defined cell cycle in which small cells elongate to about five times their original length and then divide by fragmentation. The nitrogen requirement for production of maximal number of colony-forming units was assessed by varying concentrations and kinds of nitrogen source in the medium. Ferric ammonium citrate at a concentration in 7H10 medium of 0.17 mumol/ml or ammonium chloride at 0.25 mumol/ml as the nitrogen source permitted the cells to elongate and to undergo limited division, with the final culture at 4 x 10(7) colony-forming units per ml. Ammonium chloride at 2.5 mumol/ml or glutamine at 1.37 mumol/ml supported completion of the cell cycle with final colony-forming units at about 5 x 10(8)/ml. Other amino acids, including glutamic acid, at 2.5 mumol/ml did not support completion of the cell cycle, although in most cases an intermediate number of colony-forming units per milliliter were formed. Limited uptake of [(14)C]glutamic acid and uptake of [(14)C]glutamine were not detectable until cell fission began. Cells not limited for nitrogen took up five times as much (35)S during fission as limited cells did during the same time. The nonlimited cells contained 10 times as much sulfolipid as the nitrogen-limited cells at the end of the cell cycle. These results demonstrate that rapidly dividing cells of M. avium utilize amino acids and sulfur and also synthesize sulfolipids in events that are apparently separable from metabolic functions of elongating cells. The results are contrasted with those found for other mycobacteria in which no cell cycle has been demonstrated.
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PMID:Ammonium ion requirement for the cell cycle of Mycobacterium avium. 62 92

The lysis of 14C-labeled bacteria by hydrolases of human and rabbit leukocytes was studied in vitro. While Staphylococcus albus, Streptococcus faecalis, and Streptococcus mutans were highly susceptible to lysis, Staphylococcus auresus was intermediate in its susecptibility to lysis by the leukocyte enzymes. Group A Streptococcus, Listeria monocytogenes, Shigella flexneri, Escherichia coli, and Mycobacterium smegmatis were very resistant to degradation by these enzymes. The lytic activity of leukocyte lysates from human and rabbit blood was probably due to acid hydrolases of polymorphonuclear leukocytes. Extracts of human blood monocytes and of rabbit peritoneal and lung macrophages were less lytic for the bacteria tested. Lymphocytes and platelet extracts were not bacteriolytic. The lytic effect of the leukocyte lysates was not inhibited by KCN or sodium azide, but was abolished to a large extent by cationic polyelectrolytes such as protamine sulfate, histone and leukocyte cationic proteins, and poly-lysine, as well as by the anionic polyelectrolytes such as heparin, chondroitin sulfate, DNA, carrageenin, alginate sulfate, dextran sulfate, and ploy-L-glutamic acid. Other potent inhibitors of bacteriolysis were trypan blue, congo red, phosphatidic acid, normal immunoglobulins, and components of streptococcal cell wall.
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PMID:The effect of leukocyte hydrolases on bacteria. III. Bacteriolysis induced by extracts of different leukocyte populations and the inhibition of lysis by macromolecular substances. 80 17

The chemical composition of the deproteinized, delipidated cell walls of five strains of BCG and of an attenuated human strain of Mycobacterium tuberculosis has been established, with special focus on their poly-L-glutamic acid content. All the cell walls have the same overall composition. Their poly-L-glutamic acid content varies from 0 to 4.6%. A correlation between the poly-L-glutamic acid content and the biological properties of the BCG strains reported in the literature could not be established.
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PMID:Analysis of the cell wall of five strains of Myocbacterium tuberculosis BCG and of an attenuated human strain, W 115. 81 13


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