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

The ability of Mycoplasma hyopneumoniae to agglutinate RBC was evaluated to develop an in vitro cytadsorption assay. Using swine RBC in a microtitration hemagglutination test, no agglutination or partial agglutination was detected. Comparison of RBC from various other species indicated that improved hemagglutination was obtained with RBC from turkeys. This hemagglutination was detected only when mycoplasma cells used in the assay had been frozen and thawed, heated at 50 C for 30 minutes, or treated with trypsin. Treatment of RBC with trypsin or neuraminidase enhanced hemagglutination. Possible surface lectin activity in M hyopneumoniae was evaluated by use of carbohydrates in a blocking assay; hemagglutination was not inhibited by any of 13 carbohydrates evaluated. Mycoplasma hyopneumoniae convalescent porcine serum and monoclonal antibodies against 2 M hyopneumoniae immunogens of molecular weights of 64,000 and 41,000 inhibited hemagglutination.
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PMID:Hemagglutination and hemagglutination inhibition of turkey red blood cells with Mycoplasma hyopneumoniae. 277 22

Attachment of Mycoplasma pneumoniae to host cells initiates disease, and the attachment components may represent important protective immunogens for preventing disease. We have studied the mechanisms of attachment using in vitro cell culture systems and selected pathogenic and nonpathogenic strains of M. pneumoniae. Attachment of the pathogenic strains M129 and PI-1428 was several fold greater than attachment of the nonpathogenic strain, and attachment of strains M129 and PI-1428 was reduced by 21 to 63% when human WiDr cell monolayers were exposed to neuraminidase, supporting the concept that M. pneumoniae attaches to mammalian cells by a neuraminidase-sensitive glycoconjugate. While attachment of the two pathogenic strains was markedly reduced by treating the WiDr cells with glutaraldehyde, glutaraldehyde treatment produced minimal effects on the attachment of the nonpathogenic strain B176. Glutaraldehyde treatment also altered the temperature dependence of attachment by the pathogenic strains. Because glutaraldehyde-treated WiDr cell monolayers showed little difference in attachment between pathogenic and nonpathogenic strains, glutaraldehyde-treated cells are not appropriate cell substrates for studying M. pneumoniae attachment mechanisms or identifying immunogens for vaccine development.
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PMID:Mycoplasma pneumoniae attachment to glutaraldehyde-treated human WiDr cell cultures. 308 8

Mycoplasma (M.) mobile 163K isolated from fish was investigated for its hemadsorbing, hemagglutinating, and hemolysing capacities and for its ability to adhere to erythrocytes. Hemadsorption to the colonies of M. mobile occurred with ovine, bovine, equine, trout, and carp erythrocytes and was inhibited by treatment of the mycoplasmas with substances acting on proteins (pronase, trypsin, glutaraldehyde), heat, UV-irradiation and homologous antiserum. Hemadsorption could be prevented also by treatment of the erythrocytes with neuraminidase. In liquid medium ovine erythrocytes were agglutinated and afterwards lysed by M. mobile. The erythrocytes which were adsorbed to the colonies of M. mobile were finally lysed also. Darkfield preparations showed the ability of M. mobile to adhere to erythrocytes and also its hemagglutinating properties.
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PMID:Interaction of Mycoplasma mobile 163K with erythrocytes. 343 86

The attachment of Mycoplasma pulmonis m53 organisms to mouse and rat synovial cells was examined by using the organisms and the synovial cells treated in various ways. M. pulmonis treated with trypsin attached to the synovial cells, but the organisms treated with pronase, formaldehyde, glutaraldehyde, or heat did not. These findings suggest that the sites for binding M. pulmonis to the mouse and rat synovial cells are of polypeptide nature. Treatment of M. pulmonis with sialic acid and treatment of the synovial cell sheets with neuraminidase did not affect the attachment. The synovial cell surface for receptors M. pulmonis organisms would be different from those on respiratory cells or erythrocytes for M. pneumoniae or M. gallisepticum. Even nonviable organisms and M. pulmonis membranes attached to the mouse or rat synovial cells. The nature of the receptor of mouse synovial cells would be different from that of rat cells, since rat cells were affected by treatment with formaldehyde or glutaraldehyde, but mouse cells were not.
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PMID:Attachment of Mycoplasma pulmonis to rat and mouse synovial cells cultured in vitro. 408

Monkey, rat, and chicken tracheal epithelial cells, as well as monkey, rat, guinea pig, and chicken erythrocytes, adsorbed firmly to colonies of Mycoplasma pneumoniae and M. gallisepticum. Colonies of M. pulmonis also adsorbed erythrocytes but with less avidity than M. pneumoniae or M. gallisepticum; unlike the latter organisms, M. pulmonis did not adsorb tracheal epithelial cells. Colonies of M. orale type 1 and M. orale type 3 adsorbed only chicken red cells. Other mycoplasma species tested, including four of human origin and one of animal origin, did not adsorb red cells or epithelial cells. M. pneumoniae and M. gallisepticum appeared to attach to erythrocytes or tracheal epithelial cells by neuraminic acid receptors on these cells, whereas M. orale types 1 and 3 and M. pulmonis seemed to utilize another type or other types of receptors. Pretreatment of red cells or tracheal epithelial cells with receptor-destroying enzyme, neuraminidase, or influenza B virus removed the adsorption receptors for M. pneumoniae. Similarly, pretreatment of M. pneumoniae colonies with neuraminic acid-containing materials prevented adsorption of erythrocytes or respiratory tract cells. The adsorption sites on M. pneumoniae were specifically blocked by homologous but not heterologous antisera. This property made it possible to study the nature of the mycoplasma adsorption sites by testing the capacity of different fractions of the organism to block the action of adsorption-inhibiting antibodies. Such studies suggested that the mycoplasma binding sites were probably lipid or lipoprotein in nature. The glycerophospholipid hapten was implicated as one such site, since this serologically active hapten blocked the action of hemadsorption-inhibiting antibodies in M. pneumoniae rabbit antiserum. The affinity of M. pneumoniae for respiratory tract epithelium, unique among the mycoplasmas that infect man, may play a role in virulence, since this type of attachment provides an unusual opportunity for peroxide, secreted by the organism, to attack the tissue cell membrane without being rapidly destroyed by catalase or peroxidase present in extracellular body fluids.
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PMID:Adsorption of Mycoplasma pneumoniae to neuraminic acid receptors of various cells and possible role in virulence. 418 67

A new subtype of avian influenzavirus A was isolated in January 1967 from an epizootic in a turkey hatchery in Ontario, Canada. The disease was fatal in 65 of 2 500 hens involved. Virus was isolated from lung and trachea tissue of three dead turkeys. Sera from convalescent birds contained antibody against the viruses isolated from the outbreak but not against other known type A avian influenzaviruses, Newcastle disease virus, Myxovirus Yucaipa, or Mycoplasma gallisepticum.The strain designated A/turkey/Ontario/6118/67 contained the influenza A type ribonucleoprotein. Haemagglutinin and neuraminidase antigens of the strain differed antigenically from the envelope antigens of other avian influenzaviruses isolated from birds, horses, pigs, or man. The designation of turkey/Ontario/6118/67 as containing haemagglutinin of avian subtype 8 (Hav 8) and neuraminidase of avian subtype 4 (Nav 4) is proposed.
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PMID:A new subtype of type A influenzavirus isolated from turkeys. 454 Oct 4

The whole viable Mycoplasma gallisepticum (strain TT) organisms were found to possess neuraminidase activity with a pH optimum of 5.8 on substrates such as human transferrin, human alpha(1)-glycoprotein, and rabbit serum. The enzyme operated optimally at pH 4.5 when N-acetylneuraminyl-lactose was used as the test substrate.
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PMID:Neuraminidase activity in Mycoplasma gallisepticum. 467 93

Erythrocytes and H-HeLa cells were treated with neuraminidase and then compared with untreated cells for their ability to adsorb to mycoplasma colonies or be agglutinated by suspensions of the mycoplasmas. Of the 17 mycoplasma serotypes examined, only 4 were found to use neuraminic acid receptors; these were Mycoplasma pneumoniae, M. gallisepticum, M. synoviae, and mycoplasma WR1. Not all strains of a serotype behaved alike. Thus, removal of receptors on erythrocytes for one strain of M. gallisepticum required at least 100 times the concentration of neuraminidase needed to remove them for another strain. The mechanism of attachment of erythrocytes to mycoplasma colonies does not appear to be the same as that for attachment to mycoplasmas in suspension.
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PMID:Utilization of neuraminic acid receptors by mycoplasmas. 578 18

Hemagglutination of turkey erythrocytes by Mycoplasma gallisepticum was inhibited by mucoproteins containing sialic acid, by sialic acid itself, and by treatment of the erythrocytes with neuraminidase. Neuraminidase treatment of the mucoprotein-rich inhibitors reduced or abolished their inhibitory activity. The findings indicate that sialic acid on the erythrocyte surface provides binding sites for Mycoplasma gallisepticum.
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PMID:Sialic acid binding sites: role in hemagglutination by Mycoplasma gallisepticum. 590 87

Previously isolated mutants of Mycoplasma pneumoniae incapable of hemadsorption were characterized with respect to specific protein content, tracheal ring attachment capability, and virulence for both in vitro and in vivo model systems. Two-dimensional gel electrophoresis revealed both quantitative and qualitative differences between the protein complements of two different mutant strains and that of the virulent parent strain. Studies of mycoplasma attachment to hamster tracheal rings in vitro demonstrated that only one of these mutant strains still possessed the ability to attach to the respiratory epithelium via neuraminidase-sensitive receptors. Measurement of [3H]orotic acid uptake in mycoplasma-infected tracheal rings indicated that infection with the hemadsorption-negative mutants resulted in only slight reductions of ribonucleic acid synthesis, similar to levels observed for tracheal rings infected with an avirulent strain of M. pneumoniae. The virulence potential of the two mutant strains was further investigated by utilizing the hamster model system. Both mutant strains were rapidly cleared from the lungs of infected animals and produced little or no microscopic pneumonia.
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PMID:Characterization of hemadsorption-negative mutants of Mycoplasma pneumoniae. 616 19


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