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PubMed1990

Evidence that UGA is read as a tryptophan codon rather than as a stop codon by Mycoplasma pneumoniae, Mycoplasma genitalium, and Mycoplasma gallisepticum.

Molecular cloning and sequencing showed that Mycoplasma gallisepticum, like Mycoplasma capricolum, contains both tRNA(UCA) and tRNA(CCA) genes, while Mycoplasma pneumoniae and Mycoplasma genitalium each appear to have only a tRNA(UCA) gene. Therefore, these mycoplasma species contain a tRNA with the anticodon UCA that can translate both UGA and UGG codons.

Base Sequence↗
PubMed1995

Taxonomic analysis of the tortoise mycoplasmas Mycoplasma agassizii and Mycoplasma testudinis by 16S rRNA gene sequence comparison.

The nucleotide sequences of the 16S rRNA genes of two mycoplasmas, Mycoplasma agassizii (proposed sp. nov.) and Mycoplasma testudinis, isolated from tortoises were determined and used for taxonomic comparisons. Signature nucleotide sequence motifs and overall sequence similarities to other mollicutes positioned these mycoplasmas in the M. hyorhinis and M. pneumoniae phylogenetic groups, respectively. A third, previously unrecognized tortoise mycoplasma was detected by 16S rRNA gene amplification and sequence analysis and was positioned in the M. fermentans phylogenetic group. The 16S rRNA gene of Acholeplasma laidlawii was similarly detected in a tortoise isolate, showing that diverse mollicutes can share the same family of reptilian host.

Animals↗
PubMed1977

New models of chronic synovitis in rabbits induced by mycoplasmas: microbiological, histopathological, and immunological observations on rabbits injected with Mycoplasma arthritidis and Mycoplasma pulmonis.

A dose-dependent chronic synovitis was induced in rabbit knees after the intra-articular injection of both Mycoplasma arthritidis and Mycoplasma pulmonis. The inflammation progressed from an initial acute phase at 1 week characterized by edema, infiltration of the synovium with monocytes and heterophils, and desquamation of lining cells, to a more chronic phase at 1 and 3 months, in which villus hyperplasia, lymph "nodules," mononuclear cell infiltration, fibroplasia, and collagen deposition were prominent. With one exception, mycoplasmas could no longer be cultivated from the joints 1 month postinoculation. Both mycoplasma species evoked a humoral antibody response that was more marked in synovial fluids than in peripheral blood. A cell-mediated immune reaction, as evidence by enhanced uptake by [3H]thymidine by sensitized blood, spleen, or node lymphocytes in the presence of homologous antigen, was detected only in rabbits injected with M. pulmonis. Lymphocytes taken from arthritic rabbits were no more cytotoxic toward synovial cells derived from normal or arthritic rabbits than were normal lymphocytes. The models of synovitis described in this study offer a convenient probe for determining the mechanisms of mycoplasma-induced inflammation, since they require only a single injection of the initiating agent and, in addition, utilize an animal host large enough for detailed investigation into the nature of mycoplasma/synovium interactions.

Animals↗
PubMed1990

[Evaluation of the Mycoplasma Plus and the SIR Mycoplasma kits for quantitative detection and antibiotic susceptibility testing of genital mycoplasma].

We compared the results obtained with two commercially available systems (Diagnostics Pasteur) for the quantitative identification and the antibiotic susceptibility testing of the genital mycoplasmas. Ureaplasma urealyticum and Mycoplasma hominis with established methodologies, i.e. isolation on agar with enumeration by dilutions in broth medium and MIC determinations. The Mycoplasma Plus system, consisting of six cups, was designed for the identification and quantitation of genital mycoplasmas and the detection of yeasts. Used in parallel in 150 clinical specimens, it detected U. urealyticum in 42 out of 43 and M. hominis in 10 out of 11 specimens positive by the established methodology. The SIR Mycoplasma antibiogram, consisting of 16 cups, provided for the testing of 1 or 2 concentrations (micrograms/ml) of each of 8 antibiotics: doxycycline, minocycline and lymecycline (4-8); erythromycin (1-4); josamycin (2-8); clindamycin (2); pristinamycin (2); and ofloxacin (1-4). Using an inoculum of about 10(4)-10(5) organisms/ml, we found that major part of the results was in accord with those obtained with the MIC determined in broth for U. urealyticum and on agar for M. hominis. Strains intermediate or resistant to the tetracyclines were identified. Both systems seemed suitable for clinical laboratory use.

Anti-Bacterial Agents↗
PubMed1996

Failure to detect Mycoplasma fermentans, Mycoplasma penetrans, or Mycoplasma pirum in the urethra of patients with acute nongonococcal urethritis.

Urethral swab specimens collected from 108 male Japanese patients with acute nongonococcal urethritis (NGU) and from 50 Japanese men without NGU were examined for the presence of Mycoplasma fermentans, Mycoplasma penetrans, and Mycoplasma pirum by means of polymerase chain reaction-based assays. These mycoplasmas were not detected in any of the specimens, which suggests that they are unlikely to have a pathogenic role in acute NGU.

Acute Disease↗
PubMed1990

Cross-hybridization between the cytadhesin genes of Mycoplasma pneumoniae and Mycoplasma genitalium and genomic DNA of Mycoplasma gallisepticum.

Immunological cross-reactivity was observed between the cytadhesin proteins of Mycoplasma pneumoniae and Mycoplasma genitalium and a 155 kDa protein of Mycoplasma gallisepticum. Furthermore, the cytadhesin genes of M. pneumoniae and M. genitalium were used to demonstrate homology with M. gallisepticum genomic DNA under low stringency conditions suggesting that a family of adhesin-related genes exists among these pathogenic mycoplasmas.

Adhesins, Bacterial↗
PubMed2005

Mycoplasma bovis shares insertion sequences with Mycoplasma agalactiae and Mycoplasma mycoides subsp. mycoides SC: Evolutionary and developmental aspects.

Three new insertion elements, ISMbov1, ISMbov2 and ISMbov3, which are closely related to ISMag1 (Mycoplasma agalactiae), ISMmy1 and IS1634 (both Mycoplasma mycoides subsp. mycoides SC), respectively, have been discovered in Mycoplasma bovis, an important pathogen of cattle. Southern blotting showed that the genome of M. bovis harbours 6-12 copies of ISMbov1, 11-15 copies of ISMbov2 and 4-10 copies of ISMbov3, depending on the strain. A fourth insertion element, the IS30-like element, is present in 4-8 copies. This high number of IS elements in M. bovis, which represent a substantial part of its genome, and their relatedness with IS elements of both M. agalactiae and M. mycoides subsp. mycoides SC suggest the occurrence of two evolutionary events: (i) a divergent evolution into M. agalactiae and M. bovis upon infection of different hosts; (ii) a horizontal transfer of IS elements during co-infection with M. mycoides subsp. mycoides SC and M. bovis of a same bovine host.

Animals↗
PubMed1986

Enumeration, isolation, and species identification of mycoplasmas in saliva sampled from the normal and pathological human oral cavity and antibody response to an oral mycoplasma (Mycoplasma salivarium).

Saliva samples collected from 393 subjects with and without oral diseases were examined for concentrations of mycoplasmas and Mycoplasma species. Mycoplasmas were isolated from 383 (97%) of the 393 subjects. Viable counts ranged from zero to 7.6 X 10(7) CFU/ml (median, 6.9 X 10(4)) and were significantly (P less than 0.01) higher in diseased subjects, except for those with arthrosis temporomandibularis, than in controls. Of 1,400 isolates, 897 (64%), 442 (30%), and 8 (1%) were identified as Mycoplasma salivarium, M. orale, and M. hominis, respectively, and the remaining 73 isolates (5%) were unidentifiable. More than two-thirds of the isolates from diseased subjects versus only half from controls were identified as M. salivarium. In diseased subjects other than those with ostitis (especially those with arthrosis temporomandibularis), the incidence of M. salivarium was higher than that of M. orale, whereas the former occurred about as frequently as the latter in the controls. Antibodies to M. salivarium were also measured in sera from some subjects by the metabolism inhibition test. Sera with metabolism inhibition titers of 16 or greater were rated positive. There was no significant difference in the prevalence of antibodies between diseased subjects (60%) and controls (40%), but the mean titers (97 to 220) of all positive sera from diseased subjects were two to four times those for sera from controls. In addition, a fourfold or greater rise or fall of antibody titers to the organism was shown in paired sera from some subjects. On the basis of these results, M. salivarium was strongly suggested to participate etiologically in some cases of oral infection.

Adolescent↗
PubMed2005

Hydrogen peroxide production by Mycoplasma bovis and Mycoplasma agalactiae and effect of in vitro passage on a Mycoplasma bovis strain producing high levels of H2O2.

Hydrogen peroxide (H2O2) production and oxygen uptake during the oxidation of NADH and L-alpha-glycerophosphate (GP) by lysed cells was determined for the type and field strains of Mycoplasma bovis and M. agalactiae. NADH oxidation by all the strains showed variable production of H2O2 ranging from 0 to 1.21 mol/mol O2 taken up. All strains were unable to oxidize GP, showing absence of GP oxidase activity. Some strains were identified that produced relatively high levels of H2O2 (> 1.0 mol/ mol O2 taken up). In vitro passage of M. bovis strain 119B96 showed reduced H2O2 production: 0.52, 0.16, and 0.07 mol/mol O2 taken up after the 50th, 100th and 200th passages, respectively. SDS-PAGE analysis showed the loss of a protein band of 32 kDa after 50 passages. These preliminary studies show that not only does H2O2 production by potentially pathogenic Mycoplasma spp. vary in the field but also that similar alterations can be induced by passage in culture. In the latter case, at least in one M. bovis strain, this alteration has been shown by SDS-PAGE to be associated with a loss of specific protein production. Further study of these phenomena is essential background for the production of more efficient vaccines for mycoplasmas.

Animals↗
PubMed2002

Identification and characterization of a site-specific tyrosine recombinase within the variable loci of Mycoplasma bovis, Mycoplasma pulmonis and Mycoplasma agalactiae.

Three highly mutable loci of the wall-less pathogens Mycoplasma bovis, Mycoplasma pulmonis and Mycoplasma agalactiae undergo high-frequency genomic rearrangements and generate extensive antigenic variation of major surface lipoproteins. Adjacent to each locus, an open reading frame exists as a single chromosomal copy and is predicted to encode a site-specific DNA recombinase exhibiting high homology to the recombinases XerD of Escherichia coli and CodV of Bacillus subtilis. Each of the mycoplasmal proteins are members of the lambda integrase family of tyrosine site-specific recombinases and likely mediates site-specific DNA inversions observed within the adjacent, variable loci.

Amino Acid Sequence↗
PubMed1980

Aminopeptidase activity of Acholeplasma laidlawii, Mycoplasma bovirhinis, Mycoplasma dispar and Mycoplasma bovis.

Aminopeptidase activity was demonstrated in extracts of Acholeplasma laidlawii, Mycoplasma bovirhinis, M. bovis and M. dispar. The enzyme specificity, which differed amongst the mycoplasma species examined, was characterized using 19 aminoacyl-beta-naphthylamides as substrates. The differences were detected after 4 h incubation with the substrates and potentially could be employed to aid in the characterization of certain mycoplasma species.

Acholeplasma↗
PubMedDate not supplied

In vitro susceptibilities of recent field isolates of Mycoplasma hyopneumoniae and Mycoplasma hyosynoviae to valnemulin (Econor), tiamulin and enrofloxacin and the in vitro development of resistance to certain antimicrobial agents in Mycoplasma hyopneumoniae.

The in vitro activities of valnemulin (Econor) and two other antimicrobial agents were determined against recent field strains of Mycoplasma hyopneumoniae and Mycoplasma hyosynoviae using a broth microdilution method. Valnemulin showed exceptional activity against M hyopneumoniae (MIC90 0.0005 microgram ml-1) and M hyosynoviae (MIC range 0.0001 microgram ml-1 to 0.00025 microgram ml-1) field strains. Tiamulin was 100-fold less active (MIC90 0.05 microgram ml-1) and enrofloxacin 20-fold less active (MIC90 0.01 microgram ml-1) than valnemulin against M hyopneumoniae field isolates and 20-fold to 25-fold less active (MIC range 0.0025 microgram ml-1 to 0.005 microgram ml-1) and 400-fold to 500-fold less active (MIC range 0.05 microgram ml-1 to 0.1 microgram ml-1) respectively against M hyosynoviae field isolates. No significant resistance developed to valnemulin or tiamulin in the type strain of M hyopneumoniae (strain J) or in a recent field isolate (MEVT G23) exposed to 10 in vitro passages in broths containing these antibiotics. Only slight resistance to oxytetracycline was observed. High resistance to tylosin developed in both M hyopneumoniae strains within five to seven in vitro passages in tylosin-containing broth. Providing that similar results are obtained in vivo under field conditions, valnemulin may well prove to be effective in the treatment of enzootic pneumonia and acute polyarthritis in pigs.

Animals↗
PubMed1987

Antibodies in the sera of Mycoplasma pneumoniae-infected patients against proteins of Mycoplasma genitalium and other mycoplasmas of man.

Frequency and pattern of anti-Mycoplasma genitalium antibodies in sera of 50 patients with Mycoplasma pneumoniae-infection were examined by the Western immunoblot method. The sera reacted with several proteins of M. genitalium. However, during the course of infection there was only a moderate increase of antibodies mainly against the bands of 135 and 105 kd in contrast to the more intense increase of numerous bands of M. pneumoniae. If antibodies against the 168 kd-adhesin of M. pneumoniae were isolated by affinity chromatography, only the IgG-, but not the IgM-fraction reacted with the 135 kd protein of M. genitalium. Results with rabbit antisera supported these findings, additionally indicating a lack of substantial cross reactions between M. pneumoniae and other species except M. genitalium. The development of anti M. genitalium antibodies at early age and their relatively constant pattern suggest an early immunization by so far unknown cross reacting microbial antigens. Antigenic cross reactions between proteins of M. pneumoniae and M. genitalium apparently do not play a substantial role in the diagnostic serology of M. pneumoniae disease.

Adult↗
PubMed2001

Biochemical characterization of Mycoplasma bovirhinis, Mycoplasma dispar and recent bovine isolates of Mycoplasma canis.

The pattern and kinetics of substrate utilization by the type strains of Mycoplasma canis, M. bovirhinis and M. dispar and ten recent M. canis isolates from cattle were determined. Metabolism of a range of sugars and organic acids by M. dispar was detectable by measurement of oxygen uptake. Organic acids were not utilized by M. bovirhinis or M. canis, and there was no oxygen uptake during metabolism of glucose or other sugars, as monitored by a pH-change method. The M. canis strains varied in their ability to metabolize sugars; seven of the isolates from cattle had the distinctive ability to metabolize sucrose, and one isolate, plus the type strain (from a dog), metabolized N-acetylglucosamine. The M. bovirhinis strain metabolized maltose. However, all the test strains oxidized glycerol at high rates and with a high affinity. Oxidation of glycerol has been reported for other mycoplasmas from the bovine respiratory tract and leads to the production of hydrogen peroxide, a potential virulence factor.

Acetylglucosamine↗
PubMed1984

Absence of Mycoplasma pneumoniae cytadsorption protein P1 in Mycoplasma genitalium and Mycoplasma gallisepticum.

Polyclonal and monoclonal antibodies to Mycoplasma pneumoniae protein P1 were nonreactive with whole-cell or soluble preparations of M. genitalium and M. gallisepticum. However, radioimmunoprecipitation performed with hyperimmune rabbit sera raised against each mycoplasma species indicated antigenic cross-reactivity between M. pneumoniae and M. genitalium.

Adhesins, Bacterial↗
PubMed1998

Characterization of MGC2, a Mycoplasma gallisepticum cytadhesin with homology to the Mycoplasma pneumoniae 30-kilodalton protein P30 and Mycoplasma genitalium P32.

A second cytadhesin-like protein, MGC2, was identified in the avian respiratory pathogen Mycoplasma gallisepticum. The 912-nucleotide mgc2 gene encodes a 32.6-kDa protein with 40.9 and 31.4% identity with the M. pneumoniae P30 and M. genitalium P32 cytadhesins, respectively. Functional studies with reverse transcription-PCR, immunoblotting, double-sided immunogold labeling, and attachment inhibition assays demonstrated homology to the human mycoplasmal P30 and P32 cytadhesins. These findings suggest that there is a family of cytadhesin genes conserved among pathogenic mycoplasmas infecting widely divergent hosts.

Adhesins, Bacterial↗
PubMed1992

Evidence that Lo's mycoplasma (Mycoplasma fermentans incognitus) is not a unique strain among Mycoplasma fermentans strains.

Mycoplasma fermentans incognitus has attracted much interest either as a cofactor for the progression of AIDS or as a pathogenic agent in non-AIDS-related diseases (S.-C. Lo, M. S. Dawson, P. B. Newton III, M. A. Sonoda, J. W.-K. Shih, W. F. Engler, R. Y.-H. Wang, and D. J. Wear, Am. J. Trop. Med. Hyg. 41:364-376, 1989; S.-C. Lo, M. S. Dawson, M. Wong, P. B. Newton III, M. A. Sonoda, W. F. Engler, R.Y.-H Wang, J. W.-K. Shih, H. J. Alter, and D. J. Wear, Am. J. Trop. Med. Hyg. 41:601-616, 1989; S.-C. Lo, J.W.-K. Shih, N.-Y. Yang, C.-Y. Ou, and R. Y.-H. Wang, Am. J. Trop. Med. Hyg. 40:213-226, 1989). In the present study, the genetic and serologic properties of the incognitus strain and other M. fermentans strains were compared. Furthermore, the replication of human immunodeficiency virus type 1 (HIV-1), determined by reverse transcriptase activity and HIV-1 p24 antigen level, in peripheral blood mononuclear cells was evaluated after stimulation with mycoplasma cell lysates. The psb-2.2 viruslike infectious agent DNA probe, used to identify the incognitus strain in the tissues of AIDS and non-AIDS patients by Lo et al. (Am. J. Trop. Med. Hyg. 41:364-376 and 40:213-226, 1989), showed reaction patterns similar to those of two M. fermentans strains isolated from cell cultures but not to that of the type strain PG18. Restriction enzyme patterns of the incognitus strain with EcoRI and HindIII were also similar to those of M. fermentans strains isolated from cell cultures. There were no remarkable differences in the immunoblot profiles between the incognitus strain and the other M. fermentans strains. These results suggest that the incognitus strain is not a unique strain among M. fermentans strains. Further, cell lysates of each M. fermentans strain could also enhance the replication of HIV-1 to a level similar to that of the incognitus strain as determined by the reverse transcriptase activity and the amount of the p24 antigen.

Acquired Immunodeficiency Syndrome↗