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International Journal of Systematic... Jul 1993Strain BV1 was isolated from the exudate of the footpad abscess of a black vulture (Coragyps atratus). The colonies had a "fried-egg" appearance consistent with that of... (Comparative Study)
Comparative Study
Strain BV1 was isolated from the exudate of the footpad abscess of a black vulture (Coragyps atratus). The colonies had a "fried-egg" appearance consistent with that of mycoplasmal species. Electron microscopic examination of the cells revealed irregular elongated or elliptical forms and smaller circular budding processes. Profuse growth was observed in Frey medium supplemented with 20% swine serum at 37 degrees C in a humidified atmosphere of 10% CO2 and air. Typical of mycoplasma, strain BV1 required sterol for growth and catabolized glucose but did not hydrolyze arginine or urea. The guanine-plus-cytosine content of the DNA was 28 mol%. The organism demonstrated the ability to hemolyze, absorb onto, and agglutinate the erythrocytes from several animal species. Strain BV1 was serologically unrelated by the growth inhibition test to previously established Mycoplasma, Acholeplasma, Entomoplasma, and Mesoplasma species, as well as to strains belonging to these genera but not identified to species level. Moreover, BV1 had a 16S rRNA gene with a nucleotide sequence distinct from reported sequences of other mycoplasmas. This organism represents a new species for which the name Mycoplasma corogypsi is proposed. Strain BV1 (ATCC 51148T) is the type strain of Mycoplasma corogypsi sp. nov.
Topics: Abscess; Animals; Bacterial Proteins; Base Composition; Bird Diseases; Birds; Cell Division; Hindlimb; Immunologic Techniques; Molecular Sequence Data; Mycoplasma; Mycoplasma Infections; RNA, Ribosomal, 16S; Tenericutes
PubMed: 8347515
DOI: 10.1099/00207713-43-3-585 -
Future Microbiology Jul 2010With their reduced genome bound by a single membrane, bacteria of the Mycoplasma species represent some of the simplest autonomous life forms. Yet, these minute... (Review)
Review
With their reduced genome bound by a single membrane, bacteria of the Mycoplasma species represent some of the simplest autonomous life forms. Yet, these minute prokaryotes are able to establish persistent infection in a wide range of hosts, even in the presence of a specific immune response. Clues to their success in host adaptation and survival reside, in part, in a number of gene families that are affected by frequent, stochastic genotypic changes. These genetic events alter the expression, the size and the antigenic structure of abundant surface proteins, thereby creating highly versatile and dynamic surfaces within a clonal population. This phenomenon provides these wall-less pathogens with a means to escape the host immune response and to modulate surface accessibility by masking and unmasking stably expressed components that are essential in host interaction and survival.
Topics: Animals; Antigenic Variation; Gene Expression Regulation, Bacterial; Humans; Immune Evasion; Models, Biological; Mycoplasma; Mycoplasma Infections; Recombination, Genetic
PubMed: 20632806
DOI: 10.2217/fmb.10.71 -
Microbiology and Molecular Biology... Dec 1998The recent sequencing of the entire genomes of Mycoplasma genitalium and M. pneumoniae has attracted considerable attention to the molecular biology of mycoplasmas, the... (Review)
Review
The recent sequencing of the entire genomes of Mycoplasma genitalium and M. pneumoniae has attracted considerable attention to the molecular biology of mycoplasmas, the smallest self-replicating organisms. It appears that we are now much closer to the goal of defining, in molecular terms, the entire machinery of a self-replicating cell. Comparative genomics based on comparison of the genomic makeup of mycoplasmal genomes with those of other bacteria, has opened new ways of looking at the evolutionary history of the mycoplasmas. There is now solid genetic support for the hypothesis that mycoplasmas have evolved as a branch of gram-positive bacteria by a process of reductive evolution. During this process, the mycoplasmas lost considerable portions of their ancestors' chromosomes but retained the genes essential for life. Thus, the mycoplasmal genomes carry a high percentage of conserved genes, greatly facilitating gene annotation. The significant genome compaction that occurred in mycoplasmas was made possible by adopting a parasitic mode of life. The supply of nutrients from their hosts apparently enabled mycoplasmas to lose, during evolution, the genes for many assimilative processes. During their evolution and adaptation to a parasitic mode of life, the mycoplasmas have developed various genetic systems providing a highly plastic set of variable surface proteins to evade the host immune system. The uniqueness of the mycoplasmal systems is manifested by the presence of highly mutable modules combined with an ability to expand the antigenic repertoire by generating structural alternatives, all compressed into limited genomic sequences. In the absence of a cell wall and a periplasmic space, the majority of surface variable antigens in mycoplasmas are lipoproteins. Apart from providing specific antimycoplasmal defense, the host immune system is also involved in the development of pathogenic lesions and exacerbation of mycoplasma induced diseases. Mycoplasmas are able to stimulate as well as suppress lymphocytes in a nonspecific, polyclonal manner, both in vitro and in vivo. As well as to affecting various subsets of lymphocytes, mycoplasmas and mycoplasma-derived cell components modulate the activities of monocytes/macrophages and NK cells and trigger the production of a wide variety of up-regulating and down-regulating cytokines and chemokines. Mycoplasma-mediated secretion of proinflammatory cytokines, such as tumor necrosis factor alpha, interleukin-1 (IL-1), and IL-6, by macrophages and of up-regulating cytokines by mitogenically stimulated lymphocytes plays a major role in mycoplasma-induced immune system modulation and inflammatory responses.
Topics: Animals; Humans; Mycoplasma; Mycoplasma Infections; Phylogeny; Virulence
PubMed: 9841667
DOI: 10.1128/MMBR.62.4.1094-1156.1998 -
Genetika Sep 2001Mollicutes are unique microorganisms characterized by a great extent for the reduction in genetic material, which retained the capability of independent division on... (Review)
Review
Mollicutes are unique microorganisms characterized by a great extent for the reduction in genetic material, which retained the capability of independent division on acellular nutrient media. Phenotypically mycoplasmas differed from other bacteria by their small size and lack of a cell wall (mollis, soft; cutis, skin). High dependence on metabolism components utilized in the cultivation medium and high metabolic plasticity due to the absence of many genome regulatory elements make mycoplasmas perfect parasites for cells of the eukaryotic origin. The ability of these microorganisms to pass through host cells and their assumed participation in AIDS activation facilitate the study of mycoplasma pathogenesis. Another important feature of mycoplasmas, which is expressed during their interaction with a macroorganism, is their ability to escape from the immune response of a host due to surface antigen variation. These adaptation capacities of mycoplasmas ensuring their life in various biological niches, given a limited genome and the direct metabolic dependence on an environment, cannot be adequately explained at present. In this review, we attempted to collect and systematize data that contribute to our understanding of the important feature of mycoplasmas, genetic instability, which may underlie many of their adaptive responses.
Topics: Antigens, Bacterial; Genome, Bacterial; Mycoplasma
PubMed: 11642120
DOI: No ID Found -
Frontiers in Bioscience : a Journal and... May 2006Although the field of prokaryotic cell biology is well-advanced now, mycoplasmas were the first bacteria in which the existence of a cytoskeleton was postulated. Despite... (Review)
Review
Although the field of prokaryotic cell biology is well-advanced now, mycoplasmas were the first bacteria in which the existence of a cytoskeleton was postulated. Despite this head-start, the cytoskeletons of mycoplasmas are presently less well understood than those of other bacteria. This deficit is principally attributable to three factors: the novel nature of most of the cytoskeletal elements as compared with other bacteria, which have the advantage of being related to eukaryotic cytoskeletal proteins; differences among the cytoskeletons of different mycoplasma species; and the fastidiousness of mycoplasmas, which complicates efforts to perform protein biochemistry. In better studied mycoplasmas like Mycoplasma pneumoniae, a major component of the cytoskeleton is associated with the attachment organelle, a polar structure that is essential for adherence to host cells, involved in gliding motility, and associated with cell division. Mycoplasma mobile also has structures that appear to be involved in gliding motility, though in contrast to the structures of M. pneumoniae, these are extracellular. Some other species also have distinct subcellular structures.
Topics: Adhesins, Bacterial; Bacterial Adhesion; Cell Division; Mycoplasma; Mycoplasma pneumoniae; Organelles; Phylogeny
PubMed: 16720287
DOI: 10.2741/1943 -
International Journal of Systematic... Oct 1993A mycoplasma designated strain 4229T (T = type strain) was isolated in 1984 from the turbinate of a duck in France, and similar strains were isolated from geese in... (Comparative Study)
Comparative Study
A mycoplasma designated strain 4229T (T = type strain) was isolated in 1984 from the turbinate of a duck in France, and similar strains were isolated from geese in France and from a partridge in England. All of these strains were originally identified as Mycoplasma gallisepticum by immunofluorescence and growth inhibition tests, but subsequent serological and molecular studies indicated only a partial relationship to this species and DNA-DNA hybridization studies revealed only approximately 40 to 46% genetic homology with M. gallisepticum PG31T. In this study morphological, cultural, and physical investigations were carried out on strain 4229T and partridge strain B2/85, after we first demonstrated the similarity between these organisms by performing a restriction enzyme analysis of their DNAs. Both strains had phenotypic properties very similar to M. gallisepticum properties, including the presence of an attachment organelle. As a result of these investigations, the organisms were assigned to the class Mollicutes, the order Mycoplasmatales, and the genus Mycoplasma. They fermented glucose, reduced triphenyl tetrazolium chloride aerobically and anaerobically, and exhibited hemadsorption and hemagglutination, but other biochemical tests were negative. Apart from a serological cross-reaction with M. gallisepticum, these organisms exhibited no significant relationship with any previously described Mycoplasma species as determined by growth inhibition or immunofluorescence tests or with a number of additional serovars and unclassified avian strains. This Mycoplasma taxon therefore appears to be a new species, for which we propose the name Mycoplasma imitans. The type strain is strain 4229 (= NCTC 11733 = ATCC 51306).(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Animals; Antibodies, Bacterial; Cholesterol; DNA, Bacterial; Deoxyribonucleases, Type II Site-Specific; Ducks; Microscopy, Electron; Mycoplasma; Serotyping
PubMed: 8240954
DOI: 10.1099/00207713-43-4-721 -
Antimicrobial Agents and Chemotherapy May 2002Mycoplasmas, which are bacteria that are devoid of a cell wall and which belong to the class Mollicutes, are pathogenic for humans and animals and are frequent...
Mycoplasmas, which are bacteria that are devoid of a cell wall and which belong to the class Mollicutes, are pathogenic for humans and animals and are frequent contaminants of tissue cell cultures. Although contamination of cultures with mycoplasma can easily be monitored with fluorescent dyes that stain DNA and/or with molecular probes, protection and decontamination of cultures remain serious challenges. In the present work, we investigated the susceptibilities of Mycoplasma fermentans and Mycoplasma hyorhinis to the membrane-active peptides alamethicin, dermaseptin B2, gramicidin S, and surfactin by growth inhibition and lethality assays. In the absence of serum, the four peptides killed mycoplasmas at minimal bactericidal concentrations that ranged from 12.5 to 100 microM, but in all cases the activities were decreased by the presence of serum. As a result, under standard culture conditions (10% serum) only alamethicin and gramicidin S were able to inhibit mycoplasma growth (MICs, 50 microM), while dermaseptin B2 and surfactin were ineffective. Furthermore, 8 days of treatment of HeLa cell cultures experimentally contaminated with either mycoplasma species with 70 microM enrofloxacin cured the cultures of infection, whereas treatment with alamethicin and gramicidin S alone was not reliable because the concentrations and treatment times required were toxic to the cells. However, combination of alamethicin or gramicidin S with 70 microM enrofloxacin allowed mycoplasma eradication after 30 min or 24 h of treatment, depending on the mycoplasma and peptide considered. HeLa cell cultures experimentally infected with mycoplasmas should prove to be a useful model for study of the antimycoplasma activities of antibiotics and membrane-active peptides under conditions close to those found in vivo.
Topics: Anti-Bacterial Agents; Anti-Infective Agents; Cell Membrane; Culture Media; Enrofloxacin; Fluoroquinolones; HeLa Cells; Humans; Microbial Sensitivity Tests; Microscopy, Electron; Mycoplasma; Mycoplasma fermentans; Peptides; Quinolones
PubMed: 11959548
DOI: 10.1128/AAC.46.5.1218-1225.2002 -
Chang Gung Medical Journal Apr 2003Mycoplasmas, the smallest and simplest prokaryotes that reside in endosomes of mammalian cells, are widespread contaminants found in cell cultures. About 30% of all cell...
BACKGROUND
Mycoplasmas, the smallest and simplest prokaryotes that reside in endosomes of mammalian cells, are widespread contaminants found in cell cultures. About 30% of all cell cultures, varying from 15 to 80%, are reportedly contaminated with mycoplasmas. Here, we present our experience in successfully detecting and treating mycoplasmal infection in various cell lines.
METHODS
The nested polymerase chain reaction (PCR) detection and microscopic examination, including phase-contrast, fluorescent, as well as differential interference contrast, were used for detecting potential mycoplasma contamination of cell lines used in our laboratory. As soon as mycoplasma was identified, antibiotic treatment was initiated.
RESULTS
Mycoplasmal contamination was detected in six of 15 cell lines using the nested PCR amplification of mycoplasma DNA, which was further demonstrated using 4, 6-Diamidino-2-phenylindole (DAPI) staining and fluorescent microscopy. Alternate treatment with two antibiotics, macrolide (tiamulin) and tetracycline (minocycline), effectively eliminated mycoplasma, which was validated by both PCR and microscopic studies.
CONCLUSIONS
The nested PCR using genomic DNA extracted from cultured cells as templates is a rapid and sensitive method for detecting mycoplasma contamination. Treatment with combined antibiotics can completely eradicate mycoplasmal infection from cultured cells. For the ease of use, PCR and/or DAPI staining appear suitable for detecting potential mycoplasmal contamination in laboratories that rely heavily on the cell culture system.
Topics: Anti-Bacterial Agents; Cell Line, Tumor; Humans; Mycoplasma; Polymerase Chain Reaction
PubMed: 12846524
DOI: No ID Found -
Annual Review of Microbiology 1996Although mycoplasmas lack cell walls, they are in many respects similar to the gram-positive bacteria with which they share a common ancestor. The molecular biology of... (Review)
Review
Although mycoplasmas lack cell walls, they are in many respects similar to the gram-positive bacteria with which they share a common ancestor. The molecular biology of mycoplasmas is intriguing because the chromosome is uniquely small (< 600 kb in some species) and extremely A-T rich (as high as 75 mol% in some species). Perhaps to accommodate DNA with a lower G + C content, most mycoplasmas do not have the "universal" genetic code. In these species, TGA is not a stop codon; instead it encodes tryptophan at a frequency 10 times greater than TGG, the usual codon for this amino acid. Because of the presence of TGA codons, the translation of mycoplasmal proteins terminates prematurely when cloned genes are expressed in other eubacteria, such as Escherichia coli. Many mycoplasmas possess strikingly dynamic chromosomes in which high-frequency changes result from errors in DNA repair or replication and from highly active recombination systems. Often, high-frequency changes in the mycoplasmal chromosome are associated with antigenic and phase variation, which regulate the production of factors critical to disease pathogenesis.
Topics: Chromosomes, Bacterial; DNA Repair; DNA Replication; Gene Transfer Techniques; Genome, Bacterial; Mycoplasma; Mycoplasma Infections; Recombination, Genetic
PubMed: 8905075
DOI: 10.1146/annurev.micro.50.1.25 -
Sub-cellular Biochemistry 1993
Review
Topics: Bacterial Capsules; Cell Membrane; Microscopy, Electron; Mycoplasma
PubMed: 8378989
DOI: 10.1007/978-1-4615-2924-8_6