Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A polyclonal serum sample from a lepromatous leprosy (LL) patient, which presented a specific recognition pattern for leprosin, was used to screen a Mycobacterium leprae genomic library constructed with DNA isolated from human lepromas. One clone, designated ML4-1, which expressed a specific antigenic determinant of M. leprae as part of a beta-galactosidase fusion protein, was isolated. The 1.932 bp M. leprae-derived genomic fragment was sequenced, and it had an incomplete open-reading frame shown to code for a 644 amino-acid polypeptide (72.3 kDa). Some partial nucleotide homology to the M. tuberculosis MTCY9C4 cosmid and the M. leprae B1913 cosmid were found. Southern blot assays using the 584 bp Eco RI-Bam HI fragment excised from the ML4-1 clone revealed that this sequence is present only in the M. leprae genome and not in the 24 different mycobacterial DNA tested. Two oligonucleotides based on the genomic sequence were also synthesized and used as amplifiers for a polymerase chain reaction (PCR) test, giving a positive signal exclusively in M. leprae DNA. Furthermore, 32 sequential synthetic peptides, 20 amino-acids long, spanning the entire protein corresponding to the hypothetical ML4-1 clone sequence, were synthesized and evaluated by ELISA. A peptide included in the 221-240 region was significantly recognized by either lepromatous leprosy or healthy tuberculosis contact patient sera. Thus, PCR amplification of this fragment, along with the recognition of its protein sequence by leprosy patient sera, could be a useful tool for a potential diagnostic method in the detection of M. leprae infection in the future.
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PMID:Isolation, characterization, molecular cloning and amplification of a species-specific M. leprae antigen. 1070 Sep 13

Mycobacterium leprae antigen and antibody complexes could be detected in the serum of leprosy patients using monoclonal antibody ML34 and anti-BCG antibodies by enzyme-linked immunosorbent assay. This simplified system detects disease related complexes without the need for isolating and purifying them from the serum. Immune complexes captured using monoclonal antibody ML34 revealed positivity in seven out of eight neuritic, two out of nine tuberculoid (TT), five out of ten borderline tuberculoid (BT), four out of ten borderline lepromatous (BL) and four out of ten lepromatous (LL), leprosy cases. One of the controls also showed immune complex of an IgM type. Anti-BCG based IgG immune complexes assay revealed positivity in six out of eight neuritic, one out of nine TT, four out of ten BT, two out of ten BL, four out of ten LL leprosy cases, and two out of 24 healthy controls. IgM type of mycobacterial immune complexes were almost negligible. Capture of complexes using monoclonal antibody ML34 which is against lipoarabinomannan of M. leprae seems to work better than polyclonal anti-BCG antibody. The probable role of immune complexes in nerve damage needs to be evaluated, as very high levels of immune complexes are found in neuritic leprosy by both the assays. The above test would be useful in immunodiagnosis of neuritic leprosy and also in cases where antibody response is not detectable because of the formation of immune complexes.
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PMID:Detection of disease related immune complexes in the serum of leprosy patients. A novel single step method. 1071 65

Skin testing with lepromin, which produces a delayed-type hypersensitivity reaction, has been used in the classification of leprosy, and a good correlation has been found between immunological status and the reaction to lepromin. In addition, the prognostic value of the lepromin test has been demonstrated. More recently, skin testing with two soluble antigens of Mycobacterium leprae showed no difference of the mean size of the reaction between household contacts and non-contacts, indicating that these antigens are not useful for the diagnosis of leprosy. This and other evidence points to the need for a better skin test antigen capable of detecting infection of individuals by M. leprae. Whereas serological assays for antibodies against both PGL-1 and the 35 kDa antigen of M. leprae have been found to yield positive results in 90-100% of patients with lepromatous (BL/LL) leprosy, these assays fail to identify 40-60% of patients with tuberculoid (BT/TT) leprosy, because of the presence of only an insignificant level of antibody against components of M. leprae in these patients' serum, although, in many BT patients, antibody signal could be detected in the local lesions. These data indicate that there remains a need for a specific diagnostic test for leprosy.
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PMID:Experience and lessons from the use of lepromin and Mycobacterium leprae-specific serology. 1120 90

The potential pathogenic role of Mycobacterium tuberculosis H37Rv fadD33, a gene encoding an acyl-CoA synthase that is underexpressed in the attenuated strain H37Ra, was investigated. In a first approach, fadD33 was cloned and expressed in strain H37Ra to restore gene expression and fadD33-complemented bacteria were used to investigate whether fadD33 might confer any growth advantage to M. tuberculosis H37Ra in an infection model of BALB/c mice. No differences were found in the growth rates of M. tuberculosis H37Rv, H37Ra and fadD33-complemented H37Ra in the lungs and spleen. In contrast, in the liver, where the attenuated strain H37Ra showed impaired growth compared to the virulent strain H37Rv, complementation of the attenuated strain H37Ra with fadD33 restored bacterial replication. In a further approach, the fadD33 gene of strain H37Rv was disrupted by allelic exchange mutagenesis and the virulence of the mutant strain was tested by mouse infection. It was found that disruption of fadD33 decreased M. tuberculosis H37Rv growth in the liver, but not in the lungs or spleen, and complementation of the fadD33-disrupted mutant with fadD33 restored bacterial replication in the liver, but did not affect replication in the lungs and spleen. These findings suggest that fadD33 plays a role in M. tuberculosis virulence by supporting bacterial growth in the liver.
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PMID:Involvement of the fadD33 gene in the growth of Mycobacterium tuberculosis in the liver of BALB/c mice. 1248 Aug 91

Leprosy or Hansen's disease is a chronic infectious disease caused by the Mycobacterium leprae. The skin and nervous manifestations of the disease present a singular clinical picture that is easily recognized. After India, Brazil still is the second country with the greatest number of cases in the world. Around 94% of the known cases and 94% of the new cases reported in America, come from Brazil. The disease presents itself in two well-defined stable and opposite poles (lepromatous and tuberculoid) and two unstable groups (indeterminate and dimorphic). The spectrum of presentation of the disease may also be classified as: tuberculoid tuberculoid (TT), borderline tuberculoid (BT), borderline borderline (BB), borderline lepromatous (BL) and lepromatous lepromatous (LL). The finding of acid fast bacillus in tissue is the most useful method of diagnosis. The effective treatment of leprosy includes the use of specific therapy, suppression of lepra reactions, prevention of physical incapacity, and physical and psychosocial rehabilitation. Chemotherapy with rifampin, dapsone and clofazimine have produced very good results and the control of the disease in Brazil in the foreseeable future is likely.
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PMID:[Leprosy in Brazil]. 1290 39

Bacterial enzymes of the menaquinone (Vitamin K2) pathway are potential drug targets because they lack human homologs. MenB, 1,4-dihydroxy-2-naphthoyl-CoA synthase, the fourth enzyme in the biosynthetic pathway leading from chorismate to menaquinone, catalyzes the conversion of O-succinylbenzoyl-CoA (OSB-CoA) to 1,4-dihydroxy-2-naphthoyl-CoA (DHNA-CoA). Based on our interest in developing novel tuberculosis chemotherapeutics, we have solved the structures of MenB from Mycobacterium tuberculosis and its complex with acetoacetyl-coenzyme A at 1.8 and 2.3 A resolution, respectively. Like other members of the crotonase superfamily, MenB folds as an (alpha3)2 hexamer, but its fold is distinct in that the C terminus crosses the trimer-trimer interface, forming a flexible part of the active site within the opposing trimer. The highly conserved active site of MenB contains a deep pocket lined by Asp-192, Tyr-287, and hydrophobic residues. Mutagenesis shows that Asp-192 and Tyr-287 are essential for enzymatic catalysis. We postulate a catalytic mechanism in which MenB enables proton transfer within the substrate to yield an oxyanion as the initial step in catalysis. Knowledge of the active site geometry and characterization of the catalytic mechanism of MenB will aid in identifying new inhibitors for this potential drug target.
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PMID:Crystal structure of Mycobacterium tuberculosis MenB, a key enzyme in vitamin K2 biosynthesis. 1290 28

The penultimate step of prokaryotic coenzyme A (CoA) biosynthesis is directed by the essential enzyme phosphopantetheine adenylyltransferase (PPAT; EC 2.7.7.3), an attractive target for antibiotics. The reaction catalyzed by PPAT is rate-limiting and involves the transfer of an adenylyl group from ATP to 4'-phosphopantetheine to form 3'-dephospho-CoA. Rhombohedral crystals of PPAT from Mycobacterium tuberculosis (Rv2965c) were obtained. The crystals belong to space group R32, with unit-cell parameters a = 68.69 A, alpha = 91.81 degrees. The crystals diffract to better than 2 A resolution on a Cu Kalpha rotating-anode generator. The packing density for one polypeptide chain in the asymmetric unit is 2.89 A(3) Da(-1), with a solvent content of 0.57.
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PMID:Rhombohedral crystals of Mycobacterium tuberculosis phosphopantetheine adenylyltransferase. 1468 28

In leprosy, cell-mediated immunity (CMI) is more significant than humoral response to eliminate intracellular pathogen. T cell defect is a common feature in lepromatous leprosy (LL) patients as compared to tuberculoid type (TT) patients. For efficient initiation of CD4+, T cell response requires T cell receptor (TCR) activation and costimulation provided by molecules on antigen-presenting cells (APC) and their counter receptors on T cells. In our previous study, the defective T cell function in LL patients was restored to a proliferating state with the release of TH1 type cytokines using mycobacterial antigen(s) with two immunomodulators (Murabutide (MDP-BE) and T cell epitope of Trat protein of Escherichia coli) by presenting the antigen in particulate form in vitro to PBMC derived from leprosy patients. This observation prompted us to study the expression of the costimulatory molecules (CD80, CD86, CD28, CD152), other accessory molecules (TCR alphabeta/gammadelta) and T cell lineage molecules (CD4+ and CD8+) during constitutive and activated state of peripheral blood mononuclear cells (PBMC) derived from normal and leprosy individuals using different formulations of Mycobacterium leprae total cell wall antigen (MLCWA), Trat and MDP-BE using flow cytometric analysis. An increased surface expression of CD80, CD86 and CD28 but decreased CD152 expression was observed when PBMC of normal, BT/TT (tuberculoid) and BL/LL (lepromatous) patients were stimulated in vitro with MLCWA+MDP-BE+Trat peptide using liposomal mode of antigen delivery, while opposite results were obtained with the antigen alone. Antibody inhibition study using antihuman CD80 or CD86 completely abolished the T cell lymphoproliferation, thereby reconfirming the importance of these costimulatory molecules during T cell activation/differentiation. Though the liposome-entrapped antigen formulation has no effect on expression of alphabeta/gammadelta T cell receptor, the constitutive levels of TCR gammadelta were high in lepromatous patients. Thus, TCR bearing gammadelta appears to have a negligible regulatory role in peripheral blood of leprosy patients. The percentage of cells positive for CD4+ are increased in inducible state in all the three groups, while CD8+-positive cells were decreased in LL patients, thereby reconfirming the fact that priming of CD4+ cells are necessary for producing final effector functions. Lastly, intracellular cytokine staining experiment indicated that CD4+ cells are the major producers of IFN-gamma but not NK cells. The study highlights the reversal of T cell anergy especially in lepromatous patients through the modulation of costimulatory molecule expression under the influence of Th1 cytokines, i.e., IL-2 and IFNgamma.
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PMID:Expression of costimulatory molecules (CD80, CD86, CD28, CD152), accessory molecules (TCR alphabeta, TCR gammadelta) and T cell lineage molecules (CD4+, CD8+) in PBMC of leprosy patients using Mycobacterium leprae antigen (MLCWA) with murabutide and T cell peptide of Trat protein. 1497 55

Gene fadD33 of Mycobacterium tuberculosis, one of the 36 homologues of gene fadD of Escherichia coli identified in the M. tuberculosis genome, predictively encodes an acyl-CoA synthase, an enzyme involved in fatty acids metabolism. The gene is underexpressed in the attenuated strain M. tuberculosis H37Ra relative to virulent H37Rv and plays a role in M. tuberculosis virulence in BALB/c mice by supporting mycobacterial replication in the liver. In the present paper, we investigated the role of fadD33 expression in bacterial growth within the hepatocyte cell line HepG2, as well as in human monocyte-derived THP-1 cells and peripheral blood mononuclear cells. M. tuberculosis H37Rv proved able to grow within HepG2 cells, while the intracellular replication of M. tuberculosis H37Ra was markedly impaired; complementation of strain H37Ra with gene fadD33 restored its replication to the levels of H37Rv. Moreover, disruption of gene fadD33 by allelic exchange mutagenesis reduced the intracellular growth of M. tuberculosis H37Rv, and complementation of the fadD33-disrupted mutant with gene fadD33 restored bacterial replication. Conversely, fadD33 expression proved unable to influence M. tuberculosis growth in human phagocytes, as fadD33-disrupted M. tuberculosis H37Rv mutant, as well as fadD33-complemented M. tuberculosis H37Ra, grew within THP-1 cells and peripheral monocytes basically at the same rates as parent H37Rv and H37Ra strains. The results of these experiments indicate that gene fadD33 expression confers growth advantage to M. tuberculosis in immortalized hepatocytes, but not in macrophages, thus emphasizing the importance of fadD33 in liver-specific replication of M. tuberculosis.
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PMID:Requirement of gene fadD33 for the growth of Mycobacterium tuberculosis in a hepatocyte cell line. 1516 22

This study examines the immune responses against some stress proteins of Mycobacterium leprae in leprosy patients with and without leprosy reactions. Leprosy patients showed a higher level of antibodies to all antigens compared to healthy controls. The antibody response to 18kDa antigen was significantly higher in patients with Type 1 reaction compared to those of TT or borderline patients without Type 1 reaction, or those with Type 2 reaction. Borderline (BT/BL), lepromatous (LL) and patients with reactions (Type 1 and Type 2) had higher levels of antibodies to M. leprae soluble extract (MLSE) and 65kDa than those of the tuberculoid (TT) group. LL, borderline patients, and patients with Type 1 reaction had a higher level of antibody to 28kDa than those of healthy controls. However, no significant differences could be observed in antibody response to these antigens (MLSE, 65kDa, and 28kDa) between patients with reaction and without reaction. A significant proportion of TT/BT patients showed positive lymphoproliferative response to MLSE compared to BL/LL patients. In addition, the lymphoproliferative response to MLSE was significantly greater in patients with Type 1 reaction compared to patients without reaction. No difference in proliferative response to 65kDa could be observed in any of these groups. The finding of high levels of antibodies against stress proteins in patients with Type 1 reactions, especially to 18 kDa antigen, along with a heightened lymphoproliferative response to MLSE is suggestive of a coexistence of cell mediated and humoral immunity in leprosy patients during Type 1 reactions. On the other hand, in Type 2 reactions no significant role of stress proteins could be demonstrated except a heightened lymphoproliferative response to the 28 kDa antigen.
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PMID:Leprosy reactions: humoral and cellular immune responses to M. leprae, 65kDa, 28kDa, and 18 kDa antigens. 1530 88


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