Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MYCOPLASMA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed1991

Morphological and ultrastructural studies of Mycoplasma flocculare and Mycoplasma hyopneumoniae in vitro.

Cells of Mycoplasma flocculare were found to vary in size and shape, especially in the later phases of growth, whereas those of Mycoplasma hyopneumoniae were fairly uniform irrespective of growth phases. Filamentous cells were present in cultures of M flocculare in the stationary and declining phases, but were never found in cultures of M hyopneumoniae. The filamentous and bizarre forms observed when mycoplasmas were suspended in phosphotungstic acid probably result from the action of the hypotonic solution. The surface of all cells was covered by a fuzzy coat consisting of fine hairs or bristles. An electron-lucent region was usually seen in cells negatively stained after centrifugation, but was only occasionally seen in cells negatively stained directly from the medium. Intracytoplasmic membranes were present in sectioned cells. No attachment organelle was found in cells of either species.

Animals↗
PubMed1987

Growth and interaction of Mycoplasma bovirhinis and Mycoplasma dispar in vitro.

Two mycoplasmas were grown in pure and mixed cultures in glucose calf-serum broth with initial pH 7.8. Sensitivity to pH was also tested. The main data for Mycoplasma bovirhinis and Mycoplasma dispar, respectively, in pure cultures were as follows: lag phase, days: less than 1, 1-2; log phase: 1-2, 1-4; relatively stationary phase: 0-1, 2-4; decline phase (to the extent roughly logarithmic): 2-6, 5-10; maximal titers: 5 x 10(7) to 10(9), 5 x 10(6) to 10(8) color changing units per 0.2 ml; highest pH, approximately, at which decline started: 7.7 and 7.0; definitely toxic initial pH: 5.6, 6.8; relative production of acidity; less, more. Decline either shortly ended in loss of viability or, correlated with higher pH levels, led to a prolonged maintenance in lower numbers. The decline of M. bovirhinis was postulated to be essentially caused by an autotoxic product/products other than H+. In mixed cultures an antagonistic effect due to the faster growing M. bovirhinis against M. dispar was recorded. The effect varied according to the initial numbers of organisms and their ratio. Two mechanisms seemed to be active: 1. decrease of pH somewhat below neutrality led to the death of the sensitive M. dispar; 2. M. dispar, when present in relatively high initial numbers, was inhibited by M. bovirhinis during the latter's logarithmic growth at pH-levels above 7.0, the inhibition ending shortly afterwards. A rapidly inactivated product/products of M. bovirhinis metabolism, inhibitory to M. dispar was posited. The results offer an improved insight into diagnostic practices for M. dispar.

Bacteriological Techniques↗
PubMed2002

Characterization of the Mycoplasma hominis ftsZ gene and its sequence variability in mycoplasma clinical isolates.

We cloned and sequenced Mycoplasma hominis chromosomal fragment containing ftsZ gene. The wild-type expression of the gene was shown at RNA level by reverse transcription followed by PCR amplification. We revealed that M. hominis FtsZ had a comparatively low similarity to proteins of Mycoplasma genitalium and Mycoplasma pneumoniae. After full ftsZ gene sequencing for 14 clinical isolates of M. hominis, single-nucleotide substitutions were found in 21 positions, 6 of them being common for almost all isolates. This ftsZ gene polymorphism may be used for subtyping of M. hominis in clinical samples. Expression of the M. hominis ftsZ gene in different Escherichia coli strains was also demonstrated, and M. hominis FtsZ protein was purified from E. coli cells transformed with recombinant expression plasmid. Complementation between the M. hominis FtsZ and E. coli FtsZ could be shown. The comparison of FtsZ protein structures may also be used for investigation of bacterial phylogenetic relationships.

Amino Acid Sequence↗
PubMed1984

A comparison of the methods of the European Pharmacopoeia for the detection of Mycoplasma gallisepticum and Mycoplasma synoviae.

The methods specified in the European Pharmacopoeia for the detection of Mycoplasma synoviae and Mycoplasma gallisepticum as contaminants of vaccines were compared by investigating the serological responses of chicks inoculated with dilutions of mycoplasma cultures, these cultures being titrated in parallel in vitro. Inoculation by the intrathoracic route proved to be as sensitive as, or more sensitive than the other methods and was of similar sensitivity to the in vitro titrations for both agents.

Agglutination Tests↗
PubMed2003

Distribution of the MCS4 RNA genes in mycoplasmas belonging to the Mycoplasma mycoides cluster.

MCS4 RNA is one of the small stable RNAs found in Mycoplasma capricolum subsp. capricolum type strain California kid. This RNA has a sequence similarity to that of eukaryotic U6 snRNA. There are two genes encoding MCS4 RNA, designated mcs4a and mcs4b, in the genome. Homologous sequences of these genes were not found in databases of other bacterial sequences. We searched for MCS4 RNA and its genes in other bacteria by PCR and hybridization techniques. The results strongly suggested that this RNA exists only in a limited species of mycoplasmas belonging to the Mycoplasma mycoides cluster.

Base Sequence↗
PubMed1979

Preparation of competent single-cell suspensions of Mycoplasma hominis tets and Mycoplasma salivarium tets for genetic transformation to tetracycline resistance by DNA extracted from Mycoplamsa hominis tetr.

DNA extracted from Mycomplasma hominis (Sprott strain), resistant to 100 micrograms of tetracycline/ml transformed M. hominis strain H29 and Mycoplasma salivarium strain S9, which are sensitive to 2.5 and 5.0 micrograms of tetracycline/ml, respectively, to resistance. The transformants were selected on agar medium containing 10 micrograms of tetracycline/ml. Some transformants were resistant also to 20 micrograms of tetracycline/ml, a finding confirming that transformation occurred between homologous and heterologous species and that resistance is stepwise and controlled by several genetic loci. Medium containing 10 micrograms of tetracycline/ml was bacteriostatic. Prototype experiments employing mixtures of strains that were tetr and tets (tetracycline-resistant and tetracycline-sensitive, respectively) demonstrated that tetr mutants and transformants formed typical fried-egg colonies when mixtures containing not more than 10(9) mycoplasmas were spread on tetracycline agar plates. No mutants to tetracycline resistance were detected. Both M. hominis and M. salivarium were competent after treatment with MgCl2 and CaCl2, while Mycoplasma orale type 2 was inactivated. During DNA extraction different quantities of DNA formed insoluble precipitates with protein, thus preventing quantitative experiments.

Calcium Chloride↗
PubMed1994

Cloning the ribosomal RNA operons of Mycoplasma flocculare and comparison with those of Mycoplasma hyopneumoniae.

In contrast to other mycoplasma species the 16S/23S rRNA and 5S rRNA operons of Mycoplasma flocculare and Mycoplasma hyopneumoniae map at least 150 kb apart (20% of the genome). Both operons from M. flocculare have been cloned and sequenced. The 23S rRNA gene sequence showed 96.7% homology with the corresponding gene of M. Hyopneumoniae, equalling that found earlier for 16S rRNA and confirming the close phylogenetic relationships of these organisms. A possible upstream promoter was identified. Sequence elements upstream and downstream from each structural gene could form a stem needed for maturation of the immature rRNA transcript to mature 16S and 23S rRNA. We also identified two possible stem-and-loop sequences 3' to the 23S rRNA gene. The 5S rRNA gene itself also showed high homology with the corresponding structural gene of M. hyopneumoniae, although the upstream and downstream sequences were highly heterologous.

Base Sequence↗
PubMed1992

Arginine deiminase gene of an AIDS-associated mycoplasma, Mycoplasma incognitus.

Recently, we have demonstrated by molecular cloning that a strong immunosuppressive factor derived from Mycoplasma arginini is arginine deiminase. We show here that mycoplasma species identified in many of AIDS patients also bear the arginine deiminase gene. The implication of the arginine deiminase gene detected in AIDS-associated mycoplasma species is discussed.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Microscopical evidence of mycoplasma-like organisms in mycoplasma positive bovine semen.

Contamination with mycoplasma-like organisms was observed microscopically in a bull with impaired sperm quality and positive isolation of Mycoplasma bovigenitalium and ureaplasma. The bull's spermiogram was characterized by decreased initial motility and post-freeze survival rate, primary defects in nucleoplasm, changes in tail conformation and regressive changes of the plasmalemma and acrosome. Vesiculo-lamellar bodies in the periacrosomal region were an accompanying feature. The cytologic picture described is compatible with descriptions reported earlier and related to mycoplasma infection.

Acrosome↗
PubMed1994

Detection of mycoplasma contamination in cell cultures by a mycoplasma group-specific PCR.

The suitability of a 16S rRNA-based mycoplasma group-specific PCR for the detection of mycoplasma contamination in cell cultures was investigated. A total of 104 cell cultures were tested by using microbiological culture, DNA fluorochrome staining, DNA-rRNA hybridization, and PCR techniques. A comparison of the results obtained with these techniques revealed agreement for 95 cell cultures. Discrepant results, which were interpreted as false negative or false positive on the basis of a comparison with the results obtained with other methods, were observed with nine cell cultures. The microbiological culture technique produced false-negative results for four cell cultures. The hybridization technique produced false-negative results for two cell cultures, and for one of these cell cultures the DNA staining technique also produced a false-negative result. The PCR may have produced false-positive results for one cell culture. Ambiguous results were obtained with the remaining two cell cultures. Furthermore, the presence of contaminating bacteria interfered with the interpretation of the DNA staining results for 16 cell cultures. For the same reason the hybridization signals of nine cell cultures could not be interpreted. Our results demonstrate the drawbacks of each of the detection methods and the suitability of the PCR for the detection of mycoplasmas in cell cultures.

Animals↗
PubMed1979

Interaction of Mycoplasma pneumoniae with alveolar macrophages: viability of adherent and ingested mycoplasmas.

Guinea pig peritoneal or alveolar macrophages were inoculated with Mycoplasma pneumoniae cells. Extracellular mycoplasms were killed by complement treatment, and the effect of macrophage action on the number of the remaining viable mycoplasmas was observed. The complement killing was to some extent inhibited by the presence of the macrophages, but the mechanism of this protection remains unknown. Opsonized mycoplasmas were ingested, and approximately 98% were killed within 4 h. The killing rate was somewhat lower than comparable data for bacteria, but lack of cell wall and high lipid content of the membrane apparently do not cause a significant delay in intracellular destruction.

Animals↗
PubMed1983

Infection of mouse lymphoblastoid cell lines with Mycoplasma hyorhinis: complex nature of mycoplasma-host cell interactions.

Mycoplasma hyorhinis infection of lymphoid cells is a complex process. Mycoplasmas adsorb to cell surface receptors and undergo lateral redistribution on the cell membrane. This process culminates in the formation of co-caps of mycoplasmas and specific cell surface antigens. One or more of these antigens may be a M. hyorhinis receptor(s) or may bear a receptor moiety(s). We show that the cell surface antigens Thy-1.2 and Thy-1.1, and to a lesser extent H-2 and gp70, but not T200, are co-capped with M. hyorhinis on the membranes of acutely infected mouse thymic lymphoblastoid cell lines. These antigens may represent multiple receptor(s) for M. hyorhinis since there is no correlation between the expression of any individual antigen and the susceptibility of these cell lines to infection.

Adsorption↗
PubMed1984

Identification of cross-reactive antigens between Mycoplasma pulmonis and Mycoplasma arthritidis.

Serological cross-reactivity between Mycoplasma pulmonis and Mycoplasma arthritidis was investigated by enzyme-linked immunosorbent assay, immunoanalysis of electrophoretic blots, and protein A immunoprecipitation reactions. The results demonstrate that one-way cross-reactivity was present in both hyperimmunized and naturally infected rats and that the predominant cross-reactive antigens were M. pulmonis surface proteins. Distinct immunoblot patterns were demonstrated for M. pulmonis and M. arthritidis, allowing differentiation of the two species. The response to M. arthritidis antigens during natural infections differed greatly from that during hyperimmunization. Evidence suggested that nonprotein antigens were major determinants eliciting the antibody response to this mycoplasma.

Antigens, Bacterial↗
PubMed1994

A surface epitope undergoing high-frequency phase variation is shared by Mycoplasma gallisepticum and Mycoplasma bovis.

We have recently reported that three distinct size- and phase-variable surface lipoproteins (Vsps) of the bovine pathogen Mycoplasma bovis possess a common epitope recognized by monoclonal antibody 1E5. In the present study, we show that this epitope is also present on a size-variant protein (PvpA) of the avian pathogen Mycoplasma gallisepticum. Application of monoclonal antibody 1E5 in Western immunoblot analysis of Triton X-114 phase-fractionated proteins and in colony immunoblots, as well as in trypsin and carboxypeptidase digestion experiments, has demonstrated that (i) PvpA is an integral membrane protein with a free C terminus, (ii) the shared epitope is surface exposed, and (iii) PvpA is subjected to high-frequency phase variation in expression. By using serum antibodies from M. gallisepticum-infected chickens, we were able to demonstrate the immunogenic nature of PvpA and identify three additional highly immunogenic Triton X-114 phase proteins (p67, p72, and p75) also undergoing high-frequency phase variation spontaneously and independently. Metabolic labeling experiments with [14C]palmitate and [14C]oleate revealed that PvpA, in contrast to p67, p72, and p75, is not lipid modified. Southern blot hybridization with restriction fragments carrying the pvpA gene of M. gallisepticum or the vspA gene of M. bovis against digested genomic DNA of the two Mycoplasma species indicated the absence of genetic relatedness between the pvpA and vspA genes. The apparent complexity of the antigenic variation phenomenon in M. gallisepticum is discussed.

Animals↗
PubMed1997

Depletion of alveolar macrophages exacerbates respiratory mycoplasmosis in mycoplasma-resistant C57BL mice but not mycoplasma-susceptible C3H mice.

Indirect evidence suggests that innate immune mechanisms involving alveolar macrophages (AMs) are of major importance in antimycoplasmal defense. We compared the effects of AM depletion on intrapulmonary killing of Mycoplasma pulmonis during the early phase of infection in mycoplasma-resistant C57BL/6NCr (C57BL) and mycoplasma-susceptible C3H/HeNCr (C3H) mice. More than 80% of AMs were depleted in both strains of mice by intratracheal insufflation of liposome-encapsulated dichloromethylene bisphosphonate (L-Cl2MBP), compared to no significant AM depletion in either strain following insufflation of liposome-encapsulated phosphate-buffered saline (L-PBS), PBS alone, or no treatment. AM-depleted (L-Cl2MBP) and control (L-PBS) mice were infected intranasally with 10(5) CFU of M. pulmonis UAB CT, and their lungs were quantitatively cultured to assess intrapulmonary killing at 0, 8, 12, and 48 h postinfection. AM depletion exacerbated the infection in C57BL mice by reducing killing of the organism to a level comparable to that in C3H mice without AM depletion. In contrast, AM depletion did not alter killing in C3H mice. These results directly identify the AM as the main effector cell in early pulmonary antimycoplasmal defense and suggest that differences in mycoplasmal killing by AMs may explain the resistance of C57BL mice and the susceptibility of C3H mice to mycoplasmal infection.

Animals↗
PubMed2000

Complement activation in Mycoplasma fermentans-induced mycoplasma clearance from infected cells: probing of the organism with monoclonal antibodies against M161Ag.

Mycoplasma fermentans, a cell wall-less prokaryote, is capable of infecting humans and has been suggested to serve as a cofactor in AIDS development. Recently, we discovered a novel lipoprotein with a molecular mass of 43 kDa originating from M. fermentans. This protein, named M161Ag, activated human complement via the alternative pathway and efficiently induced the proinflammatory cytokines interleukin 1beta (IL-1beta), tumor necrosis factor alpha, IL-6, IL-10, and IL-12 in human peripheral blood monocytes. It is likely that M161Ag of M. fermentans affects the host immune system upon mycoplasma infection. In this study, we developed monoclonal antibodies (MAbs) against M161Ag and examined the direct role of complement in M. fermentans infection using these MAbs as probes. M. fermentans was rapidly cleared from the surfaces of infected cells by human complement, but a low-grade infection persisted in human tumor cell lines. Mycoplasma particles remaining alive in host cells may cause recurrent infection, and liberated M161Ag may serve as a biological response modifier affecting both innate and acquired immunity.

Animals↗
PubMed1973

Interaction of Mycoplasma arthritidis and other mycoplasmas with murine peritoneal macrophages.

Neither mouse nor rat peritoneal macrophages were able to kill Mycoplasma arthritidis to any observable degree in the absence of specific hyperimmune rabbit antiserum. Although convalescent mouse and rat serum were somewhat inhibitory to M. arthritidis in the absence of macrophages, these sera did not promote active phagocytosis by peritoneal macrophages. In fact, the macrophages appeared to protect the mycoplasmas against the inhibitory effects of the antisera by stimulating their growth. Hyperimmune rabbit antiserum against M. arthritidis initiated phagocytic action and resulted in a 50-fold decrease in numbers of viable mycoplasmas by 6 h. In contrast with M. arthritidis, M. pulmonis rapidly adsorbed to the surface of peritoneal macrophages. Upon addition of specific rabbit antiserum, a rapid decrease in viable organisms occurred, and a more complete destruction of organisms ensued in comparison with M. arthritidis. M. gallinarum, as with M. arthritidis, did not adsorb to the macrophages to any great extent. Phagocytic action was observed only in the presence of homologous rabbit antiserum and was not marked until after 6 h of incubation.

Adsorption↗