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PubMed1975

Adenine formation from adenosine by mycoplasmas: adenosine phosphorylase activity.

Mammalian cells have enzymes to convert adenosine to inosine by deamination and inosine to hypoxanthine by phosphorolysis, but they do not possess the enzymes necessary to form the free base, adenine, from adenosine. Mycoplasmas grown in broth or in cell cultures can produce adenine from adenosine. This activity was detected in a variety of mycoplasmatales, and the enzyme was shown to be adenosine phosphorylase. Adenosine formation from adenine and ribose 1-phosphate, the reverse reaction of adenine formation from adenosine, was also observed with the mycoplasma enzyme. Adenosine phosphorylase is apparently common to the mycoplasmatales but it is not universal, and the organisms can be divided into three groups on the basis of their use of adenosine as substrate. Thirteen of 16 Mycoplasma, Acholeplasma, and Siroplasma species tested exhibit adenosine phosphorylase activity. M. lipophilium differed from the other mycoplasmas and shared with mammalian cells the ability to convert adenosine to inosine by deamination. M. pneumoniae and the unclassified M. sp. 70-159 showed no reaction with adenosine. Adenosine phosphorylase activity offers an additional method for the detection of mycoplasma contamination of cells. The patterns of nucleoside metabolism will provide additional characteristics for identification of mycoplasmas and also may provide new insight into the classification of mycoplasmas.

Acholeplasma laidlawii↗

PubMed1983

Cloned genomic DNA sequences from Mycoplasma hyorhinis encoding antigens expressed in Escherichia coli.

A library of cloned Mycoplasma hyorhinis genomic sequences was constructed by incorporation of EcoRI digestion fragments of mycoplasma DNA into the lambda Charon 4A bacteriophage vector. Immunological screening of recombinant phage plaques identified clones containing genes encoding mycoplasma antigenic structures expressed in an Escherichia coli host. Two such recombinant phage isolates, lambda Ch4A-MhrG1 and lambda Ch4A-MhrG28, were defined and found to contain distinct genomic sequences by analysis of restriction endonuclease fragments. Inoculation of mice with recombinant gene products from lambda Ch4A-MhrG1 yielded antiserum selectively recognizing a Mr 29,500 trypsin-sensitive mycoplasma constituent. This established a means for producing selected immunogenic mycoplasma component in a bacterial host. The cloned genomic sequences of M. hyorhinis encoding expressed mycoplasma antigens represent molecular probes that can be characterized both by specific DNA sequences and by the antigenic structure of corresponding gene products. These genomic fragments define initial physical markers of the M. hyorhinis genome and may be useful in assessing antigenic and molecular genetic relationships within the genus Mycoplasma and among other members of the class Mollicutes.

Antibodies↗

PubMed1977

Surface parasitism by Mycoplasma pneumoniae of respiratory epithelium.

Identification of the attachment factor on virulent Mycoplasma pneumoniae organisms which permits surface parasitism of respiratory epithelium was attempted. Brief pretreatment of M. pneumoniae monolayers with protease prevented mycoplasma attachment ot sensitive host cells without reducing viability of the microorganisms. Gel electrophoretic analysis of mycoplasma proteins before and after exposure of intact mycoplasmas to protease revealed the absence of a major protein species (P1) in enzyme-treated preparations while other protein bands with the exception of P2 were virtually unaffected. The absence of P1 correlated with the failure of enzyme-treated mycoplasmas to attach to tracheal explants. P1 regeneration after protease treatment of mycoplasma monolayers was directly associated with reattachment capabilities in M. pneumoniae. Erythromycin inhibited P1 resynthesis, thus preventing resumed attachment activity by mycoplasmas. Lactoperoxidase-catalyzed iodination of intact M. pneumoniae organisms further confirmed that P1 was an external membrane protein and suggested that his surface component was required for the successful membrane-membrane interaction between host and parasite.

Animals↗

PubMed1992

Association of mycoplasma with HIV-1 and HTLV-I in human T lymphocytes.

Recent findings from a number of investigators suggest associations between mycoplasma and HIV or AIDS. We used a quantitative morphometric technique to analyze electron micrographs of human T lymphocytes that were infected with both mycoplasma and/or HIV-1. We observed that lymphocytes which were associated with HIV-1 were much more likely to be associated with mycoplasma than cells that were not (p < .001). Similarly, cells with associated HTLV-I were more likely to be associated with mycoplasma than cells which were not associated with mycoplasma (p < .0001). In addition, mycoplasma and virus were observed in the same region in 90% of cases. These observations suggest that adherence of mycoplasma to lymphocytes that are chronically infected with human retrovirus may trigger viral release.

Cell Line↗

PubMed1993

Mycoplasmas stimulate replication of human immunodeficiency virus type 1 through selective activation of CD4+ T lymphocytes.

Because mycoplasma infection has often been observed in individuals infected with human immunodeficiency virus type 1 (HIV-1), we investigated the influence of mycoplasmas on HIV replication in vitro. Replication of HIV-1 assessed by reverse transcriptase activity and the p24 antigen level in peripheral blood mononuclear cells (PBMCs) was enhanced by the stimulation with the cell lysates of human mycoplasmas such as Mycoplasma pneumoniae, M. genitalium, and M. fermentans. The most drastic increase of HIV-1 replication was shown in M. pneumoniae, which induced an approximately 10-fold higher replication level than phytohemagglutinin. Stimulation with the mycoplasmas accompanied the induction of blastotransformation of CD4+ but not CD8+ T lymphocytes in PBMCs and the most predominant alterations were induced by the stimulation with M. pneumoniae among the species examined. Production of IL-2 was significantly increased by stimulation with all three species of Mycoplasma used. These results suggest that mycoplasmas induce vigorous replication of HIV-1 through the activation of CD4-positive T lymphocytes.

CD4-Positive T-Lymphocytes↗

PubMedDate not supplied

Translocation of Thy-1 antigen and a fluorescent lipid probe during lymphoblastoid cell interaction with Mycoplasma hyorhinis.

The translocation of membrane-associated components during in vitro surface interactions between BW5147 murine T-lymphoblastoid cells and Mycoplasma hyorhinis was investigated. Thy-1 antigen (shown to be selectively associated with mycoplasmas following their detachment from infected BW5147 cells) was found by immunoferritin techniques to be localized at the surface of organisms colonizing lymphoblastoid cells. These results are consistent with a transfer of Thy-1 to membranes of mycoplasmas on the lymphoid cell surface. The exchange of membrane lipid-associated components was further investigated with the fluorescent lipid probe 1,6-diphenyl-1,3,5-hexatriene (DPH). Fluorescence polarization of DPH was much less pronounced in uninfected BW5147 cells than in mycoplasmas--a result indicating markedly different probe environments. The increase of fluorescence intensity and the characteristic polarization in mycoplasmal supernatant fractions obtained after incubation of organisms with DPH-labeled BW5147 cells indicated translocation of DPH from lymphoid cells to mycoplasmas. Incorporation of the probe into mycoplasmas using supernatants from DPH-labeled BW5147 cells (incubated alone) was not demonstrated; this observation is consistent with, but does not prove, a contact-dependent process of exchange. Direct monitoring of the exchange of surface antigens and lipophilic probes may be useful in studying the interaction of hydrophobic surface glycoproteins with membranes and the role of membrane components in mycoplasma-host cell interactions.

Animals↗

PubMed2000

Comparative potency of gemifloxacin, new quinolones, macrolides, tetracycline and clindamycin against Mycoplasma spp.

This study determined the comparative in vitro potency of the new investigative quinolone gemifloxacin (SB-265805) using low-passaged clinical isolates and type strains of mycoplasma commonly found in the human respiratory and urogenital tracts. Organisms studied were Mycoplasma pneumoniae, Mycoplasma hominis, Mycoplasma fermentans, Mycoplasma genitalium, Mycoplasma penetrans and Ureaplasma urealyticum, obtained from different geographical regions. Comparator drugs were levofloxacin, trovafloxacin, grepafloxacin, azithromycin, clarithromycin, tetracycline and clindamycin. MICs were determined using a microbroth dilution method. The overall range of MICs of gemifloxacin was < or =0.008-0.125 mg/L for different Mycoplasma spp. and < or =0.008-0.5 mg/L for Ureaplasma spp. Depending on the species tested, gemifloxacin showed variable results when compared with the macrolides. However, gemifloxacin was as potent as, or more potent than, tetracycline, clindamycin and the other quinolones investigated.

Anti-Bacterial Agents↗

PubMed1982

Ribosomal RNA genes in Mycoplasma.

Using Southern blotting analysis with labelled mycoplasmal ribosomal RNA as probe, two fragments (1 Kb and 5 Kb) were detected in an EcoR I digest of Mycoplasma capricolum DNA. This analysis revealed that the 5 Kb fragment carries both 16S rRNA sequences and the entire 23S rRNA gene of this mycoplasma. The 1 Kb fragment contains 16S rRNA sequences only. The 5 Kb EcoR I fragment has been cloned and used to characterize the structure of rRNA cistrons in various Mycoplasma strains. These experiments clearly demonstrate a substantial homology of Mycoplasma capricolum rRNA sequences with the E. coli rRNA cistron on one hand, and with Mycoplasma mycoides subsp. capri and Acholeplasma laidlawii on the other hand. This analysis also reveals two rRNA cistrons in Mycoplasma mycoides subsp. capri and Acholeplasma laidlawii whereas one rRNA cistron is present in Mycoplasma capricolum.

Acholeplasma laidlawii↗

PubMed2004

Mycoplasma ovis comb. nov. (formerly Eperythrozoon ovis), an epierythrocytic agent of haemolytic anaemia in sheep and goats.

Eperythrozoon ovis, an erythrocytic agent that causes haemolytic anaemia in sheep and goats, occurs worldwide and is currently thought to be a rickettsia. To determine the relationship between this agent and other haemotrophic bacterial parasites, the 16S rRNA gene of this organism was sequenced. Phylogenetic analysis revealed that this wall-less bacterium is not a rickettsia, but a mycoplasma. This mycoplasma is related closely to several other uncultivated, epierythrocytic mycoplasmas that comprise a recently identified group, the haemotrophic mycoplasmas (haemoplasmas). The haemoplasma group is composed of former Eperythrozoon and Haemobartonella species, as well as newly identified epierythrocytic mycoplasmas. Haemoplasmas parasitize the surface of erythrocytes of a wide variety of vertebrate animal hosts and are transmitted mainly by blood-feeding arthropod vectors. Recognition that E. ovis is a mycoplasma provides a new approach to dealing with this bacterium. It is proposed that E. ovis should be reclassified as Mycoplasma ovis comb. nov.

Anemia, Hemolytic↗

PubMed2006

Biofilm formation by mycoplasma species and its role in environmental persistence and survival.

Although mycoplasmas possess a very limited genome, little is known about their virulence mechanisms and methods of persistence in the host. Examination of a wide range of mycoplasma species found considerable variation in their ability to form a biofilm. Mycoplasma putrefaciens, M. cottewii, M. yeatsii, M. agalactiae and M. bovis produced prolific biofilms. Conversely, the highly pathogenic mycoplasma and causative agent of contagious bovine pleuropneumonia, Mycoplasma mycoides subsp. mycoides SC, was unable to produce a biofilm. Biofilms were found to be considerably more resistant to stress, including heat and desiccation, than planktonic cells. A link between the biofilm phenotype and genotype as determined by molecular typing was found for M. bovis. Analysis of biofilms using fluorescent staining combined with confocal microscopy demonstrated that mycoplasma biofilms formed a highly differentiated structure with stacks and channels. Biofilm formation may indicate that mycoplasmas are capable of surviving in the environment.

Anti-Bacterial Agents↗

PubMed1982

Comparison of ciliostasis by mycoplasmas in mouse and chicken tracheal organ cultures.

The cilia-stopping effect of mycoplasmas of human and various animal origin in mouse and chicken tracheal organ cultures was studied. From the results in mouse tracheal organ cultures, the mycoplasma strains tested were divided into three groups: Mycoplasma pulmonis m53, M pulmonis JB, M. pulmonis OK, M. mycoides subsp. Mycoides PGl and M. Gallisepticum S6 showed a strong cilia-stopping effect; M. pulmonis PG22, M. mycoides subsp. capri PG3, M. meleagridis 19729, M. neurolyticum Type A and M. arthritidis PG6 showed a mild effect; and M. pneumoniae FH, M. salivarium Hup, M. hominis type 1-C and M. orale N-C human origin and Acholeplasma laidlawii PG8 showed a weak effect. On the other hand, in chicken tracheal organ cultures, only M. gallisepticum S6 showed a strong effect, M. meleagridis 19729 was affected to a lesser degree, and the other mycoplasma strains showed a weak or no effect. The results indicate that some murine and poultry mycoplasmas showed a cilia-stopping tendency in mouse and chicken tracheal organ cultures, respectively, while human mycoplasmas showed weak or little effect in both organ cultures. In mouse tracheal organ cultures, M. pulmonis m53 treated with heat, trypsin or formaldehyde, and the sterile filtrate of an m53 broth culture showed no cilia-stopping effect. The relationship of the pathogenicity of mycoplasmas for their natural hosts to that for cultured respiratory cells is discussed.

Animals↗

PubMed1996

Contamination with Mycoplasma spp. induces interleukin-13 expression by human skin fibroblasts in culture.

The mycoplasmas comprise a discrete group of microorganisms that are known to exert a range of effects upon cells derived from the immune system. Some of these interactions turn out to be immunomodulatory, such as polyclonal stimulation of T and B cells or enhancement of the cytolytic potential of macrophages, NK cells and T lymphocytes. Immunologically committed cells, when infected with mycoplasmas, can also increase the production of cytokines (IL-1, IL-2, IL-4 and IL-6), interferon (IFN) gamma, tumor necrosis factor-alpha (TNF-alpha) and colony-stimulating factors (particularly GM-CSF). Moreover, mycoplasmas are potent inductors of cytokine secretion by fibroblasts in culture. Since growth factors are determinants for the activation and proliferation of immunocompetent cells in vitro, we decided to investigate if these effects are concordant with the finding of mycoplasma contamination. In order to address this question, we compared the pattern of lymphokine secretion by normal-derived human fibroblasts in culture with and without Mycoplasma spp. contamination. We found those human fibroblasts that have been contaminated with mycoplasma show production of IL-13 at the transcriptional level. This effect coincides with discrete morphological changes as compared to uncontaminated human fibroblasts. This is the first report to acknowledge that mycoplasma contamination can induce mRNA expression for IL-13 in cultured human fibroblasts.

Cell Line↗

PubMed1993

Mycoplasma cells stimulate in vitro activation of plasminogen by purified tissue-type plasminogen activator.

In an in vitro direct assay with tissue-type plasminogen activator (tPA), plasminogen and the chromogenic substrate S-2251, the ability of Mycoplasma fermentans KL4 to stimulate tPA-mediated activation of plasminogen to plasmin was studied. Mycoplasma cells markedly enhanced the activation of plasminogen by tPA in a concentration-, temperature- and pH-dependent manner. Nonidet P-40 (0.01%), sonication, and freezing and thawing of the cells substantially increased the stimulatory effect of mycoplasma on tPA activity. In contrast, the activation of plasminogen by urokinase was refractory to mycoplasma cells. The mycoplasma-mediated stimulation of tPA activity was prevented by epsilon-aminocaproic acid (EACA), a lysine analogue known to block lysine-binding sites (LBS) in plasminogen and tPA. Among several Mycoplasma fermentans strains tested, incognitus strain demonstrated the highest stimulation activity. These results suggest that mycoplasma cells interact with LBS in tPA and plasminogen to enhance plasminogen activation.

Enzyme Activation↗

PubMed1994

Sequence analysis of 16S rRNA from mycoplasmas by direct solid-phase DNA sequencing.

Automated solid-phase DNA sequencing was used for determination of partial 16S ribosomal DNA sequences of mycoplasmas. The sequence information was used to establish phylogenetic relationships of 11 different mycoplasmas whose 16S rRNA sequences had not been determined earlier. A biotinylated fragment corresponding to positions 344 to 939 in the Escherichia coli sequence was generated by PCR. The PCR product was immobilized onto streptavidin-coated paramagnetic beads, and direct sequencing was performed in both directions. One previously unclassified avian mycoplasma was found to belong to the Mycoplasma lipophilum cluster of the hominis group. Microheterogeneities were discovered in the rRNA operons of Mycoplasma mycoides subsp. mycoides (SC type), confirming the existence of two different rRNA operons. The 16S rRNA sequence of M. mycoides subsp. capri was identical to that of M. mycoides subsp. mycoides (type SC), except that no microheterogeneities were revealed. Furthermore, automated solid-phase DNA sequencing was used to identify a mycoplasmal contamination of a cell culture as Mycoplasma hyorhinis, which proved to be very difficult by conventional methods. The results suggest that the direct solid-phase DNA sequencing procedure is a powerful tool for identification of mycoplasmas and is also useful in taxonomic studies.

Base Sequence↗

PubMed2005

Versatile use of oriC plasmids for functional genomics of Mycoplasma capricolum subsp. capricolum.

Replicative oriC plasmids were recently developed for several mollicutes, including three Mycoplasma species belonging to the mycoides cluster that are responsible for bovine and caprine diseases: Mycoplasma mycoides subsp. mycoides small-colony type, Mycoplasma mycoides subsp. mycoides large-colony type, and Mycoplasma capricolum subsp. capricolum. In this study, oriC plasmids were evaluated in M. capricolum subsp. capricolum as genetic tools for (i) expression of heterologous proteins and (ii) gene inactivation by homologous recombination. The reporter gene lacZ, encoding beta-galactosidase, and the gene encoding spiralin, an abundant surface lipoprotein of the related mollicute Spiroplasma citri, were successfully expressed. Functional Escherichia coli beta-galactosidase was detected in transformed Mycoplasma capricolum subsp. capricolum cells despite noticeable codon usage differences. The expression of spiralin in M. capricolum subsp. capricolum was assessed by colony and Western blotting. Accessibility of this protein at the cell surface and its partition into the Triton X-114 detergent phase suggest a correct maturation of the spiralin precursor. The expression of a heterologous lipoprotein in a mycoplasma raises potentially interesting applications, e.g., the use of these bacteria as live vaccines. Targeted inactivation of gene lppA encoding lipoprotein A was achieved in M. capricolum subsp. capricolum with plasmids harboring a replication origin derived from S. citri. Our results suggest that the selection of the infrequent events of homologous recombination could be enhanced by the use of oriC plasmids derived from related mollicute species. Mycoplasma gene inactivation opens the way to functional genomics in a group of bacteria for which a large wealth of genome data are already available and steadily growing.

Bacterial Outer Membrane Proteins↗

PubMed1971

Cultivation of Mycoplasmas on glass.

Eight Mycoplasma species of human origin were successfully cultivated on glass. Complement-fixing (CF) antigens prepared from glass-adherent mycoplasmas were potent, specific, and free from anticomplementary activity. PPLO broth medium supplemented with 1 to 5% PPLO serum fraction (bovine), 2.5% fresh yeast extract, and 1% glucose (glycolytic species) or 1% arginine (arginine-utilizing species) supported moderate to luxuriant growth of mycoplasmas on glass. The potency of CF antigens prepared from glass-adherent mycoplasmas varied with the species of Mycoplasma tested and the duration of incubation. When the potency of CF antigens prepared from glass-adherent mycoplasmas was compared with that material sedimented from the broth phase of the same culture, three patterns of growth were observed: M. hominis and M. orale type 2 grew preferentially in the broth phase; M. salivarium, M. orale types 1 and 3, M. pneumoniae, and M. lipophilum preferentially adhered to the glass; and M. fermentans was biphasic. The growth of mycoplasmas on glass provides a simple means of concentrating and purifying such organisms for immunological and biochemical studies.

Acetates↗

PubMed1974

Serological comparison of five arginine-utilizing Mycoplasma species by two-dimensional immunoelectrophoresis.

Five arginine-utilizing, nonglycolytic Mycoplasma species were compared serologically by two dimensional immunoelectrophoresis. The survey included: Mycoplasma hominis, Mycoplasma arthritidis, Mycoplasma gateae, Mycoplasma gallinarum, and three strains of Mycoplasma arginini. Although the M. arginini strains showed strong cross-reactions, each strain produced a different antigenic profile which was distinct and which indicated significant antigenic differences between strains. The M. arginini strains showed strong relationships with M. gateae; lesser cross-reactions were observed with other strains. Common antigens were demonstrable in the entire group. When all these species were compared with a glycolytic species, Mycoplasma gallisepticum, no cross-reactions were observed. Two-dimensional immunoelectrophoresis was a far more sensitive technique than double-immunodiffusion since as many as 20 components could be resolved.

Animals↗

PubMed1985

Surface proteins of Mycoplasma hyopneumoniae identified from an Escherichia coli expression plasmid library.

A genomic library of Mycoplasma hyopneumoniae was constructed by cloning random DNA fragments approximately 300 base pairs long in a fusion expression plasmid, pEx29, containing the N terminus of the phage MS2 polymerase under the control of the PL promoter of phage lambda. Clones that produced fusion proteins carrying surface-specific antigenic determinants were identified by using antiserum raised in a pig by intranasal inoculation of viable mycoplasmas. Rabbit antisera produced against gel-purified fusion proteins synthesized in Escherichia coli were analyzed by Western blotting to identify antigenically related mycoplasma components. Distinct mycoplasma proteins termed P90, P68, P50, P30, and P26 were identified. Evidence for the surface location of P90, P68, and P50 was provided by their sensitivity to trypsin and their comigration with lactoperoxidase-catalyzed iodinated proteins of intact mycoplasmas. Immune electron microscopy, performed with antiserum against the hybrid MS2-mycoplasma protein produced in E. coli and corresponding to P90, also showed that its antigenic determinant is associated with the mycoplasma surface.

Bacterial Proteins↗