Interaction of Mycoplasmas With Host Cells

Abstract

-The mycoplasmas form a large group of prokaryotic microorganisms with over 190 species distinguished from ordinary bacteria by their small size, minute genome, and total lack of a cell wall. Owing to their limited biosynthetic capabilities, most mycoplasmas are parasites exhibiting strict host and tissue specificities. The aim of this review is to collate present knowledge on the strategies employed by mycoplasmas while interacting with their host eukaryotic cells. Prominant among these strategies is the adherence of mycoplasma to host cells, identifying the mycoplasmal adhesins as well as the mammalian membrane receptors; the invasion of mycoplasmas into host cells including studies on the role of mycoplasmal surface molecules and signaling mechanisms in the invasion; the fusion of mycoplasmas with host cells, a novel process that raises intriguing questions of how microinjection of mycoplasma components into eukaryotic cells subvert and damage the host cells. The observations of diverse interactions of mycoplasmas with cells of the immune system and their immunomodulatory effects and the discovery of genetic systems that enable mycoplasmas to rapidly change their surface antigenic composition have been important developments in mycoplasma research over the past decade, showing that mycoplasmas possess an impressive capability of maintaining a dynamic surface architecture that is antigenically and functionally versatile, contributing to the capability of the mycoplasmas to adapt to a large range of habitats and cause diseases that are often chronic in nature.

Mycoplasma infection suppresses p53, activates NF-κB and cooperates with oncogenic Ras in rodent fibroblast transformation

“…Although they have a significant impact on the cellular metabolism and physiology of their host (consumption of nutrients, production of reactive oxygen species (ROS) and so on) and are known to play causative roles in a number of diseases (for example, pneumonia, tracheitis, arthritis, uretritis and so on), mycoplasmas frequently persist as chronic, asymptomatic infections in humans and animals (Razin et al, 1998;Rottem, 2003). Similarly, mycoplasmas are common contaminants of laboratory cell cultures that usually do not affect cell growth and therefore remain undetectable in the absence of molecular or immunological assays.…”

Detecção do Grupo Mycoplasma mycoides por imunoperoxidase indireta (IPI) e PCR-REA em conduto auditivo de bovinos

“…A dificuldade em tipificar isolados de campo é freqüente devido às semelhanças antigênicas das cepas e também pela presença de cepas intermediárias entre alguns sorotipos ou sorogrupos. Isto se deve principalmente a sua alta plasticidade genotípica (Dybvig & Voelker 1996, Rottem 2003, Razin et al 2008, assim com frequencia estas cepas podem se adaptar a diferentes hospedeiros, tornando mais difícil o diagnóstico em amostras de campo em animais assintomáticos.…”

Spreading Factors of Mycoplasma alligatoris , a Flesh-Eating Mycoplasma

“…Because the major mycoplasmal pathogens of humans and domesticated animals lack endotoxin or classical exotoxins but are cytadherent, current mycoplasmology studies are focused on the roles of adhesin molecules and adherence-mediated modulation of colonized hosts to explain mycoplasmal pathogenicity. Probably because it is not a usual feature of the common mycoplasmoses of humans or domesticated animals, the possibility that spreading factors like sialidases, hyaluronidases, or mucinases, the opposites of adhesins, may exist in mycoplasmas and be important contributors to virulence in other mycoplasmoses seems to have been virtually ignored, even in otherwise exhaustive reviews of mycoplasmal pathogenicity (34,41,45).…”