Mycoplasma incognitus
A Microbial Biorealm page on the genus Mycoplasma incognitus
Classification
Higher order taxa
Bacteria; Tenericutes; Mollicutes; Mycoplasmatales; Mycoplasmataceae; Mycoplasma
Species
M. incognitus
Description and significance
Mycoplasma incognitus is a human cell invasive mycoplasma and a disease agent that can cause a variety of human diseases including AIDS, Chronic Fatigue Syndrome, Type 1 Diabetes, Parkinson's Disease, and Rheumatoid Arthritis [3]. M. incognitus belongs to the Bacterial Domain and is thought to be a mutated form of the Brucella bacterium combined with the Visna virus, from which the mycoplasma is extracted [4]. M. incognitus is an immunomodulatory agent, which means it can alter the immune response by reducing the ability of the immune system to produce antibodies [3]. This mycoplasma is highly pathogenic and can be passed from person to person via bodily fluids.
Genome structure
There is new solid genetic support for the hypothesis that mycoplasmas in general have evolved as a gram positive bacteria by the process of reductive evolution. During this process, mycoplasmas lost considerable portions of their ancestor's chromosomes but retained the genes essential for life [5]. That being said, Mycoplasma incognitus acts as a parasite and gains most of its nutrients from its host because it has a very small genome consisting of only the genes essential for life. It is estimated that M. incognitus has less than 500 genes and could have a genome as small as 600 kb [
Cell and Colony Structure
There have been frequent unsuccessful attempts at isolating a culture of M. incognitus, but it is known that the most frequently colonized sites are epithelial cell surfaces [1].
Metabolism
M. incognitus can utilize glucose both aerobically and anaerobically, and can metabolize arginine.
Ecology
M. incognitus is an obligate pathogen and cannot survive unless it is inside a host.
Pathology
M. incognitus is able to control a person's immune response and can either stimulate or suppress lymphocytes. It can also modulate the activities of monocytes, macrophages, and NK cells. Mycoplasma-mediated secretion of proinflammatory cytokines by macrophages, and up-regulating cytokines by lymphocytes, plays a major role in the inflammatory response.
References
1. Campo, Laura et al. (1998) Genotypic and Phenotypic Analysis of Mycoplasma fermentans Strains Isolated From Different Host Tissues J Clin Microbiol. 36(5): 1371-1377
2. Razin, Shmuel, Yogev, David and Naot, Yehudith (1998) Molecular Biology and Pathogenicity of Mycoplasmas Microbial Mol Biol Rev. 62(4): 1094-1156
3. Schaeverbeke, Thierry et al. (1998) Genotypic Characterization of Seven Strains of Mycoplasma fermentans Isolated From Synovial Fluids of Patients With Arthritis J Clin Microbiol. 36(5): 1226-1231
Edited by Keisha Picknell of Dr. Lisa R. Moore, University of Southern Maine,
Department of Biological Sciences, http://www.usm.maine.edu/bio
