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Query: UMLS:C0026936 (Mycoplasma)
 14,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Attachment of washed Mycoplasma gallisepticum cells to glass was quantified with organisms in which membrane lipids were labelled with 3H. Siliconization of the test tubes decreased attachment, while centrifugation increased it. Attachment increased with temperature, decreased with increasing pH and ionic strength of the attachment mixture, but was unaffected by Ca2+, Mg2+ and EDTA. This suggests that ionic bonds, but not salt bridges, participate in the attachment process. Glycophorin, the major receptor responsible for M. gallisepticum attachment to erythrocytes, partially inhibited the attachment of the organisms to glass. However, bovine serum albumin also decreased attachment. Extensive pretreatment of the organisms with trypsin decreased their ability to attach to glass by about 35 to 40%. Trypsin and pronase failed to detach the organisms already bound to glass, suggesting that external mycoplasma cell components, other than membrane proteins, also participate in attachment of the organisms to glass.
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PMID:Adherence of Mycoplasma gallisepticum to glass. 3 84

Cytomegalovirus-induced DNA polymerase can be distinguished from infected-cell enzymes by activity in 100 mM (NH4)2SO4. Virus polymerase is stimulated to 145% of control, whereas mock-infected cell polymerase is inhibited to 12% of control without added salt. Mycoplasmas induce a DNA polymerase in cell extracts that is stimulated to 130 to 180% by 25 mM (NH4)2SO4. Mycoplasma DNA polymerase may be mistaken for a virus-induced polymerase when virus stocks are contaminated. Identification of virus, cellular, and mycoplasma DNA polymerases in total cell extracts is described using sedimentation rate and effect of inhibitors on DNA polymerase activities.
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PMID:Distinguishing cytomegalovirus, mycoplasma, and cellular DNA polymerases. 18 34

An actin-like protein has been identified in cell extracts from the prokaryote Mycoplasma pneumoniae. This protein bears a striking resemblance to actin from vertebrates: (i) the solubility of the protein during isolation is analogous to that of actin bound to myosin (soluble in high ionic strength salt solution and insoluble at low ionic strength), (ii) sodium dodecyl sulfate treatment of the partially purified M. pneumoniae extract produces a protein with an electrophoretic mobility very close to that of vertebrate actin in sodium dodecyl sulfate/polyacrylamide gels, (iii) treatment of preparations with ATP-Mg2+ allows separation of long curvilinear filaments, 5-6 nm wide, that closely resemble eukaryotic filamentous actin, and (iv) the prokaryotic filamentous actin binds vertebrate heavy meromyosin fragments to form hybrid compleexes with the characteristic shape of periodic repeating arrowheads, and no heavy meromyosin is bound in the presence of ATP.
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PMID:Extraction of an actin-like protein from the prokaryote Mycoplasma pneumoniae. 33 56

We investigated 22 mycoplasma and acholeplasma species for their ability to reduce tetrazolium salts by using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. The test results were evaluated visually, as well as spectrophotometrically, by using an enzyme-linked immunosorbent assay reader. Our results were very similar to the results obtained when the tetrazolium salt reduction assay described by Aluotto et al. was used. However, the MTT reduction assay appeared to be better because it is faster, more objective and sensitive, easier to evaluate, and less expensive; in addition, it allows quantitative determinations. By using regression analysis a linear correlation between formazan production and the number of colony-forming units was demonstrated for all of the species investigated, indicating that the MTT assay can also be used for growth, toxicity, or chemosensitivity tests for the mycoplasma species that are capable of reducing tetrazolium salts.
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PMID:Tetrazolium [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] reduction by mycoplasmas. 150 78

Monospecific polyclonal antibodies that were generated against the beta-subunit of Escherichia coli ATPase (F1Fo) cross-reacted with a protein present in the cells of several Mycoplasma and Acholeplasma species. In Mycoplasma gallisepticum, the reactive protein was found almost exclusively in the cell membrane. This protein had an apparent molecular mass of approximately 52 kDa and could not be released from the membranes by repeated washings with either low or high salt solutions in the presence or absence of EDTA. The reactive protein was found to be catalytically active, exhibiting up to 44% of the total membrane-bound ATPase activity. We suggest that mycoplasmas possess a F1Fo-ATPase which undergoes structural modification(s) allowing its integration into the membrane.
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PMID:The beta-subunit of the F1F0-ATPase is conserved in mycoplasmas. 287 12

Smith, Paul F. (University of South Dakota, Vermillion). Comparative biosynthesis of ornithine and lysine by Mycoplasma and L forms. J. Bacteriol. 92:164-169. 1966.-Seven species of Mycoplasma, two L forms not requiring salt and their parent bacteria, and two yeasts were examined for enzymes involved in the biosynthesis of ornithine and lysine. All organisms tested, except two species of Mycoplasma and the yeasts, decarboxylated meso-alpha, epsilon-diaminopimelic acid. None of the Mycoplasma species or L forms was capable either of reducing alpha-aminoadipic acid to its semialdehyde or of incorporating alpha-aminoadipic acid-6-C(14) into lysine. All organisms, except the yeasts and Mycoplasma sp. caprine strain 14, acetylated glutamic acid, and all organisms possessed N(alpha)-acetyl-l-ornithine:2-oxo-glutarate aminotransferase activity. N(alpha)-acetylornithase activity was negligible in all organisms except Proteus and its L form. No transacetylation between acetylglutamic acid and ornithine, and vice versa, was demonstrable in any of the organisms. Mycoplasma species appear to possess the bacterial pathway to lysine. Ornithine does not appear to arise from glutamic acid.
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PMID:Comparative biosynthesis of ornithine and lysine by Mycoplasma and L forms. 594 Dec 75

The mechanism(s) of interaction between Mycoplasma pulmonis and eucaryotic cells was studied by adherence to and hemagglutination of erythrocytes. Simple and complex carbohydrates and glycoproteins were unable to inhibit either adherence or hemagglutination, indicating that neither was a lectin activity. Both interactions appeared to be hydrophobic due to their requirement for salt and their sensitivity to temperature. Hemagglutination, but not adherence, was inhibited by both trypsin and glutaraldehyde treatment of the mycoplasma, suggesting that adherence and hemagglutination are qualitatively different. The erythrocyte receptor sites for the two activities were also separable since hemagglutination, but not adherence, required trypsinization of erythrocytes. The hemagglutinin was shown to be an integral mycoplasma component and not a broth contaminant. Once removed, hemagglutinating activity could not be replenished by incubation in serum or broth at 4 degrees C, but could be regenerated during protein synthesis under nonreplicative conditions. Thus, a mycoplasma membrane protein was detected which was capable of interacting with opposing membrane surfaces through hydrophobic interactions. Consequently, a multiphasic model of M. pulmonis-eucaryotic cell interactions was proposed.
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PMID:Multiphasic interactions of Mycoplasma pulmonis with erythrocytes defined by adherence and hemagglutination. 671 40

The process of attachment of Mycoplasma hominis and M. orale to HAIN-55 cells, derived from normal embryonic human lung, was investigated quantitatively. The attachment reached its maximum within about 2-4 hr at 37 degrees C and increased linearly as a function of the number of organisms present in the system. The relative attachment efficiency of M. hominis was approximately 1% under our experimental conditions. Trypsin and EDTA were effective in detaching particles of M. hominis and M. orale from the surfaces of HAIN-55 cells. Therefore it was suggested that some proteinaceous substance and salt bridges might be involved in the attachment of these mycoplasmas to HAIN-55 cells.
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PMID:Attachment of Mycoplasma hominis and M. orale to human diploid lung fibroblasts. 679 14

Adherence of Mycoplasma hyopneumoniae to the mucosa of the distal portion of the respiratory tract of swine is an important initial event in development of mycoplasmal pneumonia. A suitable in vitro model of adherence would be useful for investigation of mycoplasmal and host cell factors involved in this process. We have developed an adherence assay, using suspensions of porcine respiratory tract ciliated epithelial cells and M hyopneumoniae. Tracheal epithelial cells, collected by use of cytologic brushes, were mixed with broth cultures of M hyopneumoniae and the mixtures were incubated, diluted, vortexed, and sedimented. Pellets were spread on glass slides, stained with a fluorescent antibody against M hyopneumoniae, and evaluated by fluorescent microscopy. Fluorescence was observed principally among cilia on the ciliated tufts of epithelial cells. Only a few organisms were observed adhering on the nonciliated parts of ciliated cells or on other cell types. When mycoplasmas were preincubated with low dilutions of serum from swine convalescing from M hyopneumoniae disease, attachment was partially inhibited (P < 0.05). Significant inhibition of attachment was not observed when organisms were preincubated with higher dilutions of convalescent serum, with purified IgG from hyperimmune serum against M hyopneumoniae, or with low dilutions of lung lavage fluids (from convalescent swine) that contained specific IgA antibodies against M hyopneumoniae. Preincubation of the organisms with periodate and trypsin abolished attachment and formaldehyde decreased it (P < 0.05), whereas a variety of carbohydrates had no effect on attachment. Preincubation with dextran sulfate, ammonium sulfate, magnesium sulfate, and methionine reduced attachment (P < 0.05). Treatment of cell-Mycoplasma mixtures with the hydrophobic bond-breaking agent tetramethylurea, or incubation in absence of salt, or at low temperature also reduced attachment (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Adherence of Mycoplasma hyopneumoniae to porcine ciliated respiratory tract cells. 821 93

The polymerase chain reaction (PCR) was developed using infectious laryngotracheitis virus (ILTV) primers made from a portion of the ILTV thymidine kinase gene. DNA from various ILTV field isolates, from the USDA challenge strain of ILTV, and from commercial ILTV vaccines was specifically amplified. No amplification occurred using template DNA from uninfected chicken-embryo liver cells (CELC), several nonavian alphaher-pesviruses, Mycoplasma gallisepticum, Mycoplasma synoviae, Pasteurella hemolytica, Escherichia coli, a group I avian adenovirus, fowl poxvirus, or a psittacid herpesvirus. The 647-base pair-amplified ILTV PCR product was labeled to create a nonradioactive, biotinylated DNA probe. Hybridization using the probe detected ILTV DNA. Both PCR and hybridization yielded positive results with ILTV DNA but not with the DNA of other pathogens. Hybridization was specific for ILTV using a stringent salt solution for a 30-min wash step or a somewhat less stringent salt solution for a 60-min wash step. However, slight hybridization occurred with CELC DNA when the less stringent salt solution was used in a 30-min wash step.
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PMID:Development of a polymerase chain reaction and a nonradioactive DNA probe for infectious laryngotracheitis virus. 871 48


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