Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026936 (Mycoplasma)
 14,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Surface structures of the genital mycoplasmas Ureaplasma urealyticum and Mycoplasma hominis that are important in the human immune response and pathogenesis of disease are relatively poorly defined. In this study, an unusual antigen complex of U. urealyticum consisting of multiple bands forming a "ladder" pattern after electrophoretic separation was noted. It is similar to the variable V-1 surface antigen of Mycoplasma pulmonis. Data on U. urealyticum are only preliminary, but the ureaplasma antigen, if it proves to be analogous to V-1, may provide the antigenic determinants for distinguishing among serovars or serogroups and correlating them with pathogenicity. Surface proteins of M. hominis were identified with use of 125I surface labeling, [35S]methionine metabolic labeling, and immunoadsorption of rabbit antiserum. Comparison of M. hominis reference strains PG-21 and 4195 showed little homology between surface proteins, although with metabolic labeling they appeared essentially identical. Immunoblotting with patients' sera, using PG-21 as antigen, showed that most reactions were directed to surface proteins and that a 102K antigen (MH1) was recognized by 94% of the sera. MH1 was one of the few surface proteins of PG-21 that appeared to have counterparts in the other six reference strains, making MH1 a prime candidate for reliable and specific detection of M. hominis infection.
 ...
PMID:Protein antigens of genital mycoplasmas. 305 6

Triton X-114 (TX-114)-phase fractionation was used to identify and characterize integral membrane surface proteins of the wall-less procaryote Mycoplasma hyorhinis GDL. Phase fractionation of mycoplasmas followed by analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed selective partitioning of approximately 30 [35S]methionine-labeled intrinsic membrane proteins into the TX-114 phase. Similar analysis of [3H]palmitate-labeled cells showed that approximately 20 proteins of this organism were associated with lipid, all of which also efficiently partitioned as integral membrane components into the detergent phase. Immunoblotting and immunoprecipitation of TX-114-phase proteins from 125I-surface-labeled cells with four monoclonal antibodies to distinct surface epitopes of M. hyorhinis identified surface proteins p120, p70, p42, and p23 as intrinsic membrane components. Immunoprecipitation of [3H]palmitate-labeled TX-114-phase proteins further established that surface proteins p120, p70, and p23 (a molecule that mediates complement-dependent mycoplasmacidal monoclonal antibody activity) were among the lipid-associated proteins of this organism. Two of these proteins, p120 and p123, were acidic (pI less than or equal to 4.5), as shown by two-dimensional isoelectric focusing. This study established that M. hyorhinis contains an abundance of integral membrane proteins tightly associated with lipids and that many of these proteins are exposed at the external surface of the single limiting plasma membrane. Monoclonal antibodies are reported that will allow detailed analysis of the structure and processing of lipid-associated mycoplasma proteins.
 ...
PMID:Association of lipids with integral membrane surface proteins of Mycoplasma hyorhinis. 333 43

Surface protein antigens of Mycoplasma hyopneumoniae were identified by direct antibody-surface binding or by radioimmunoprecipitation of surface 125I-labeled proteins with a series of monoclonal antibodies (MAbs). Surface proteins p70, p65, p50, and p44 were shown to be integral membrane components by selective partitioning into the hydrophobic phase during Triton X-114 (TX-114)-phase fractionation, whereas p41 was concomitantly identified as a surface protein exclusively partitioning into the aqueous phase. Radioimmunoprecipitation of TX-114-phase proteins from cells labeled with [35S]methionine, 14C-amino acids, or [3H] palmitic acid showed that proteins p65, p50, and p44 were abundant and (with one other hydrophobic protein, p60) were selectively labeled with lipid. Covalent lipid attachment was established by high-performance liquid chromatography identification of [3H]methyl palmitate after acid methanolysis of delipidated proteins. An additional, unidentified methanolysis product suggested conversion of palmitate to another form of lipid also attached to these proteins. Alkaline hydroxylamine treatment of labeled proteins indicated linkage of lipids by amide or stable O-linked ester bonds. Proteins p65, p50, and p44 were highly immunogenic in the natural host as measured by immunoblots of TX-114-phase proteins with antisera from swine inoculated with whole organisms. These proteins were antigenically and structurally unrelated, since hyperimmune mouse antibodies to individual gel-purified proteins were monospecific and gave distinct proteolytic epitope maps. Intraspecies size variants of one surface antigen of M. hyopneumoniae were revealed by a MAb to p70 (defined in strain J, ATCC 25934), which recognized a larger p73 component on strain VPP11 (ATCC 25617). In addition, MAb to internal, aqueous-phase protein p82 of strain J failed to bind an analogous antigen in strain VPP11. These studies establish that a highly restricted set of distinct, lipid-modified hydrophobic membrane proteins are major surface antigens of M. hyopneumoniae and that structural variants of surface antigens occur within this species.
 ...
PMID:Major membrane surface proteins of Mycoplasma hyopneumoniae selectively modified by covalently bound lipid. 368 Jan 70

As part of an investigation of the tRNA genes of Mycoplasma mycoides, two HindIII fragments of mycoplasma DNA comprising 0.4 and 2.5 kilobases (kb), respectively, were cloned in pBR322 and their nucleotide sequences determined. Only one tRNA gene was found in the 0.4 kb fragment, the gene for tRNAArg with the anticodon TCT, while the 2.5 kb fragment contained nine different tRNA genes arranged in a cluster which presumably constitutes a transcriptional unit. The clustered tRNA genes, with their respective anticodons, were as follows: Arg (ACG), Pro (TGG), Ala (TGC), Met (CAT), Ile (CAT), Ser (TGA), fMet (CAT), Asp (GTC), and Phe (GAA).
 ...
PMID:Cloning and nucleotide sequence analysis of transfer RNA genes from Mycoplasma mycoides. 391 26

The uptake of l-histidine by Mycoplasma fermentans and l-methionine by M. hominis was found to be dependent on temperature and pH and to follow saturation kinetics. Several metabolic inhibitors inhibited this uptake. The transport system for l-methionine was highly specific. The l-histidine transport system was less specific, and the uptake was competitively inhibited by l-arginine and l-lysine. l-Histidine accumulated in the intracellular pool of M. fermentans at a concentration about 200 times that found in the medium. Efflux of accumulated l-histidine was demonstrated at 37 C, but not at 0 C. The rate of efflux was greatly accelerated by addition of l-histidine to the medium. The findings indicate that the Mycoplasma cell membrane contains specific transport systems resembling the permease systems of other microorganisms.
 ...
PMID:Amino acid transport in Mycoplasma. 565 75

Human synovial cells, fetal skin fibroblasts and rat granulation tissue fibroblasts were experimentally infected with Mycoplasma pulmonis, a species identified as a contamination of cell cultures, and studied for collagen, total protein and glycosaminoglycan synthesis. Hyaluronic acid and sulfated glycosaminoglycan synthesis were stimulated in cultures where the infection reduced cell density, while they were retarded in cultures which had proliferated into higher density than the controls. An extra polypeptide with molecular weight of 20 kD was seen in [35S]methionine-labelled cells. Media of rat granulation tissue cells showed a shift of a 39-42 kD polypeptide to 33-36 kD position in [35S]methionine and [3H]proline labellings. Other minor changes were also noticed. Collagen synthesis or procollagen conversion to collagen were, however, not altered.
 ...
PMID:Effect of Mycoplasma pulmonis infection on protein and glycosaminoglycan synthesis of cultured connective tissue cells. 662 51

The growth of Mycoplasma hominis is stimulated by arginine. A possible mechanism for degradation of this amino acid is the arginine dihydrolase pathway. The first enzyme of the pathway, arginine deiminase, is inducible in M. hominis. Evidence exists that the dihydrolase pathway is not the major pathway to production of adenosine triphosphate in the organism. M. hominis does not take up nucleosides from the growth medium, although the metabolic processes required for the transformation of precursors into nucleic acids are present. The system by which L-methionine is transported across the cellular membrane of M. hominis resembles the active-transport systems found in other microorganisms. The membrane of M. hominis contains a high level of cholesterol in the unesterified form. The low-density fraction of human serum lipoprotein is an effective cholesterol donor, as are cholesterol-phospholipid liposomes with a high cholesterol content.
 ...
PMID:Biochemistry of Mycoplasma hominis. 666 67

During studies of human hematopoietic cells, two novel anti-mycoplasma monoclonal antibodies reacting in human cell surface binding assays were generated. These monoclonal antibodies define antigens (called MP71 and MP33) that showed variable positive and negative expression in different cultures of the same human cell lines. Furthermore, negative cell cultures could be converted to positive cultures upon incubation with filtered media from a previously positive cell culture. A DNA staining assay was used to demonstrate the presence of mycoplasma in the cultures positive for MP71. The expression of MP71 on a panel of cell lines always correlated with the expression of MP33, suggesting that the latter antigen is also mycoplasma related. The monoclonal antibodies against both antigens (MP71 and MP33) were each able to block the growth of mycoplasma newly transferred to hematopoietic cell cultures. Biosynthesis of these mycoplasma antigens differed from biosynthesis of host cell surface antigens in that the former showed a relative insensitivity to gamma irradiation. Internal labeling with 35S-methionine or host cell surface labeling with 125I and analysis by immunoprecipitation showed that the antigens MP71 and MP33 had sizes of Mr 71,000 and 33,000, respectively. Also the antigen MP71 was almost completely, although transiently, cleared from the host cell surface by trypsin. Growth inhibition analysis of different mycoplasma species indicated that the monoclonal antibody recognizing MP71 was uniquely reactive with Mycoplasma hyorhinis.
 ...
PMID:Monoclonal antibodies reacting with immunogenic mycoplasma proteins present in human hematopoietic cell lines. 714 4

The gene (ptsH) for the phosphocarrier protein, HPr, of the phosphoenolpyruvate:sugar phosphotransferase system from Mycoplasma capricolum was previously cloned and sequenced. We present here the results of experiments in which the ptsH gene was cloned into a vector for high level expression in Escherichia coli of the phosphocarrier protein. Conditions were developed for overproduction and purification of HPr by a two-column procedure. The purified protein, analyzed by Edman degradation and mass spectrometry, was found to have been processed by removal of the N-terminal methionine residue. Examination of the purified protein by gel electrophoresis under isoelectric focusing conditions revealed that it has an unusually high isoelectric point.
 ...
PMID:Overproduction and purification of the Mycoplasma capricolum phosphocarrier protein, HPr, of the phosphoenolpyruvate: sugar phosphotransferase system. 760 68

The arginine deiminase (AD) gene was cloned from Mycoplasma arginini and expressed in the cytosol of Escherichia coli as inclusion bodies with an expression level of at least 20% of the total bacterial proteins. The inclusion bodies were solubilized with 6 M guanidine hydrochloride (Gdn-HCl) under reducing conditions, in order to avoid incorrect disulfide-bond formation of the recombinant (r-) AD molecules, and renaturation was performed under various refolding conditions. The optimum renaturation conditions were found to be incubation for 90 h at pH 7.5 and 15 degrees C. The resulting completely refolded r-AD was purified to homogeneity by anion-exchange and arginine-affinity chromatography and its activity yield was 72.5%. The specific activity of the purified r-AD was comparable to and its amino acid composition was identical to those of Mycoplasma AD, and NH2-terminal sequence analysis revealed that its methionine residue corresponding to the translation initiation codon had been removed completely. Anti-tumor activity analyses showed that r-AD inhibited the growth of two mouse cell lines, hepatoma MH134 and fibrosarcoma Meth A, strongly in vitro at concentrations in excess of 10 ng ml-1. Moreover, when MH134-implanted mice were given single intravenous injections of r-AD at doses of 50 mg kg-1 and higher, their survival times were prolonged significantly. These results, taken together, indicate that the enzymatic properties and biological actions of r-AD were highly consistent with those of Mycoplasma AD.
 ...
PMID:High-level expression of Mycoplasma arginine deiminase in Escherichia coli and its efficient renaturation as an anti-tumor enzyme. 776 34


<< Previous 1 2 3 4 5 Next >>