ABSTRACT
Mycoplasma spp. are members of the class Mollicutes, have the smallest cells among free-living eubacteria, and have genomes presumed to approach the minimal essential information for independent cellular life (1). Mycoplasmas and the other mollicutes evolved from Gram-positive ancestors (2) by reductive processes that resulted in obligate association with eukaryotic host cells. The distinguishing characteristics of mollicutes include absence of a cell wall, small cell size (200–500 nm), small genome size (580–2200 kbp), low G + C content (typically in the range of 23–34 mol%, but 40 mol% in Mycoplasma pneumoniae), 16S rDNA sequences clearly affiliated with the class (3), unique codon usage (e.g., UGA as a tryptophan codon) in some lineages, and minimal metabolic capabilities. Cells are bound only by a single membrane, resulting in a general cellular pleomorphism; however, cytoskeletal elements confer helicity or polarity in a small number of species. Some species exhibit rotatory, flexional, or gliding motility. The best-studied mollicutes are significant pathogens of humans, domesticated animals, or plants. Additionally, a small number of species are common contaminants of in vitro eukaryotic cell cultures (4). Scientific organizations devoted to the study of these unique organisms include The International Organization for Mycoplasmology (https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781003099277/74b9c3bd-1cdd-4578-a0b7-bff8c162683d/content/www.IOM-Online.org" xmlns:xlink="https://www.w3.org/1999/xlink">IOM-Online.org) and its International Research Programme on Comparative Mycoplasmology, The United States Organization for Mycoplasmology (https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781003099277/74b9c3bd-1cdd-4578-a0b7-bff8c162683d/content/www.USOMycoplasmology.org" xmlns:xlink="https://www.w3.org/1999/xlink">USOMycoplasmology.org), The Asian Organization for Mycoplasmology (square.umin.ac.jp/aom/), European Society for Clinical Microbiology and Infectious Disease Study Group for Mycoplasma Infections, the International Committee for the Systematics of Prokaryotes subcommittee for the Taxonomy of Mollicutes, Australian Society for Microbiology (Division of Medical and Veterinary Microbiology, Special Interest Group for Mycoplasmatales), and Division G of the American Society for Microbiology (https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781003099277/74b9c3bd-1cdd-4578-a0b7-bff8c162683d/content/www.ASM.org" xmlns:xlink="https://www.w3.org/1999/xlink">ASM.org). The purpose of this chapter is to introduce scientists who have been trained in other disciplines to Mycoplasma and related organisms, and to provide an entry to the literature of practical mycoplasmology with emphasis on vaccinology and methods of genetic manipulation for microbiologists who specialize in other species.
