Association of a major protein antigen of Mycoplasma arthritidis with virulence

A Review of Ureaplasma diversum: A Representative of the Mollicute Class Associated With Reproductive and Respiratory Disorders in Cattle

The Mollicutes class encompasses wall-less microbes with a reduced genome. They may infect plants, insects, humans, and animals including those on farms and in livestock. Ureaplasma diversum is a mollicute associated with decreased reproduction mainly in the conception rate in cattle, as well as weight loss and decreased quality in milk production. Therefore, U. diversum infection contributes to important economic losses, mainly in large cattle-producing countries such as the United States, China, Brazil, and India. The characteristics of Mollicutes, virulence, and pathogenic variations make it difficult to control their infections. Genomic analysis, prevalence studies, and immunomodulation assays help better understand the pathogenesis of bovine ureaplasma. Here we present the main features of transmission, virulence, immune response, and pathogenesis of U. diversum in bovines.

Design of PCR-based method for detection of a gene-encoding Mycoplasma arthritidis mitogen superantigen in synovial fluid of rheumatoid arthritis patients

BACKGROUND AND OBJECTIVES

Mycoplasma arthritidis mitogen (MAM) superantigen has been shown to induce chronic arthritis, which resembles human rheumatoid arthritis (RA) in a rodent model. However, its role as a causative agent in human RA is not well understood yet. The aim of this study was to investigate the presence of MAM superantigen gene in the synovial fluid (SF) of RA patients.

MATERIALS AND METHODS

The MAM superantigen gene a reference was synthesized based on GenBank Data base (Gene ID: 6418105). Specific primer pairs were designed and PCR amplification was performed for MAM superantigen gene detection. A total of 133 SF samples of RA patients were assayed. The PCR products were subjected to sequencing and were descriptively analyzed.

RESULTS

The results of the PCR product sequencing showed the method has objective applicability and accuracy. The sensitivity of the PCR reaction for the reference DNA template was 1ng/ml. The PCR results assay of the 133 SF samples raveled that, 9.7% and 22.5% of them were positive for the MAM superantigen gene and Mycoplasma pneumoniae (M. pneumoniae), respectively.

CONCLUSION

In this study, two Mycoplasma genomes were detected with increased frequency in RA SF patients' samples. This finding appears to be a promising instrument in the etiological diagnostic of RA patients and could also lead to improved treatment selection. Further research on the other Mycoplasma species present in the SF of RA patients is essential.

Mycoplasma pulmonis Vsa proteins and polysaccharide modulate adherence to pulmonary epithelial cells

The Mycoplasma pulmonis Vsa proteins are a family of size- and phase-variable lipoproteins that shield the mycoplasmas from complement and modulate attachment to abiotic surfaces. Mycoplasmas producing a long Vsa protein hemadsorb poorly and yet are proficient at colonizing rats and mice. The effect of the length of the Vsa protein on the attachment of mycoplasmas to epithelial cells has not been previously explored. We find that independent of Vsa isotype, mycoplasmas producing a long Vsa protein with many tandem repeats adhere poorly to murine MLE-12 cells compared with mycoplasmas producing a short Vsa. We also find that mutants lacking the EPS-I polysaccharide of M. pulmonis exhibited decreased adherence to MLE-12 cells, even though it has been shown previously that such mutants have an enhanced ability to form a biofilm.

Association of Mycoplasma arthritidis mitogen with lethal toxicity but not with arthritis in mice

Mycoplasma arthritidis induces an acute to chronic arthritis in rodents. Arthritis induced in mice histologically resembles human rheumatoid arthritis and can be associated with lethal toxicity following systemic injection. The M. arthritidis mitogen (MAM) superantigen has long been implicated as having a role in pathogenesis, but its significance with respect to toxicity and arthritogenicity in mycoplasma-induced disease is unclear. To study the pathogenic significance of MAM, M. arthritidis mutants that overproduced or failed to produce MAM were developed. MAM overproduction and knockout mutants were more and less mitogenic, respectively, than the wild-type strain. The degree of mitogenic activity correlated with lethal toxicity in DBA/2J mice. In contrast, histopathological studies detected no correlation between MAM production and the severity of arthritis induced in DBA/2J and CBA/J mice.

Genome of Mycoplasma arthritidis

The genomes of several species of mycoplasma have been sequenced. Most of these species rely on the glycolytic pathway for energy production, with the one exception of Ureaplasma, a species that breaks down urea as its principle source of acquiring energy. Several species, including as Mycoplasma arthritidis, are nonglycolytic and can use arginine as their source of energy. Described here are the genome sequence and a transposon library of M. arthritidis. The genome of 820,453 bp is typical in size for a mycoplasma and contains two large families of genes that are predicted to code for phase-variable proteins. The transposon library was constructed using a minitransposon that inserts stably into the mycoplasma genome. Of the 635 predicted coding regions, 218 were disrupted in a library of 1,100 members. Dispensable genes included the gene coding for the MAM superantigen and genes coding for ribosomal proteins S15, S18, and L15.

Interactions between mycoplasma lipid-associated membrane proteins and the host cells

Mycoplamas are a group of wall-less prokaryotes widely distributed in nature, some of which are pathogenic for humans and animals. There are many lipoproteins anchored on the outer face of the plasma membrane, called lipid-associated membrane proteins (LAMPs). LAMPs are highly antigenic and could undergo phase and size variation, and are recognized by the innate immune system through Toll-like receptors (TLR) 2 and 6. LAMPs can modulate the immune system, and could induce immune cells apoptosis or death. In addition, they may associate with malignant transformation of host cells and are also considered to be cofactors in the progression of AIDS.

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.