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PubMedDate not supplied

Emmy Klieneberger-Nobel Award Lecture: The protein fingerprints of mycoplasmas.

The proteins of 91 strains of Mycoplasma from 19 established species and three groups of uncertain taxonomic position were separated by two-dimensional polyacrylamide gel electrophoresis. Considerable variations in protein patterns were found among strains from the same species or subspecies; the percentage of matching spots (% of congruence) ranged from 42%-100%, but many proteins were strongly conserved in all strains of a given species. Maps of these conserved proteins could be used to identify strains. It was concluded that (1) large colony-type strains of Mycoplasma mycoides subspecies mycoides are more closely related to M. mycoides subspecies capri than to small colony-type strains of M. mycoides subspecies mycoides; (2) Mycoplasma capricolum, Leach group 7, and the F38 group of mycoplasmas are all related to M. mycoides; (3) the 2D group of strains are not related to either M. mycoides or Mycoplasma bovis, (4) M. bovis and Mycoplasma agalactiae are closely related; (5) apart from a small overlap in pattern between Acholeplasma laidlawii and Acholeplasma granularum, the type strains of seven established species of Acholeplasma each had distinct protein patterns that justified their classification as separate species; and (6) analysis of two-dimensional protein patterns is a valuable method for resolving problems in mycoplasma taxonomy and for identifying strains.

Acholeplasma↗

PubMed1992

Prevalence of mycoplasmas in the respiratory tracts of pneumonic calves.

The prevalence of mycoplasmas in the respiratory tracts of 148 pneumonic calves originating from 25 herds in the Netherlands is reported. Four types of culture media were used to isolate mycoplasmas: solid modified Edward medium, 2 types of Friis media, and A7B differential agar medium. Mycoplasmas were isolated both from nasal swab specimens and lung lavage fluids collected from live calves and from nasal mucosa and lung tissue specimens collected post mortem. All of the mycoplasma strains isolated could be identified as either Ureaplasma diversum (isolated from 80% of 25 herds), Mycoplasma dispar (92%), M. bovirhinis (88%), M. bovis (20%), M. bovigenitalium (4%), M. arginini (16%), or M. canis (12%). Isolation rates of M. dispar and U. diversum were considerably higher from lung lavage fluids than from nasal swab specimens. M. bovis was detected only in fattening herds and not in dairy herds. The respiratory tracts of 75% of the calves examined contained at least 2 mycoplasma species. In total, 25 different combinations of mycoplasma species were detected in specimens collected from noses and lungs. The pathogenic species U. diversum and M. dispar had not been isolated before in the Netherlands.

Animals↗

PubMed2005

Mycoplasma mastitis: a review of transmission and control.

The Mycoplasma sp. that cause mastitis are simple, cell wall-less, bacteria that can colonize and cause diseases in other extramammary sites in the bovine. Prevalence of mycoplasma mastitis appears to be increasing in many locations throughout the world. The best method to identify this group of pathogens is through direct culture on mycoplasma agar media. However, limitations with this culture procedure are the duration of culture, 10 days, special conditions required and thus added expense, and the lack of primary specificity to distinguish between true pathogens and commensal organisms. Thus culture of bulk tank milk samples has been advocated as a primary screening method to determine the mycoplasma status of a herd. This monitoring system is reasonably successful but the sensitivity of detection of Mycoplasma sp. in bulk tank milk is affected by a significant minority of cows that might shed the organism at levels below the threshold of detection. Contagious mastitis control procedures have been effective in controlling outbreaks of mycoplasma mastitis. Yet new methods of control might be warranted, methods that may prevent the outbreak. Current data suggests that a significant number of new outbreaks may occur via internal or animal-to-animal transmission of mycoplasma mastitis pathogens from asymptomatic carriers.

Animals↗

PubMed1994

Mycoplasma contamination of chlamydiae isolated from clinical specimens.

Ten Chlamydia pneumoniae strains were screened for Mycoplasma contamination using two differently designed Mycoplasma-specific polymerase chain reactions (PCR). The primers of the Mycoplasma-specific PCR designed by Spaepen et al. (9) cross-reacted with all of the C. pneumoniae strains giving false-positive results. When the 10 strains of C. pneumoniae were tested for mycoplasmas with the PCR designed by Harasawa et al. (5), only 3 were positive. Mycoplasmas were cultured from these three C. pneumoniae strains confirming the latter PCR results. The PCR of Harasawa et al. (5) was highly specific for mycoplasmas and did not cross-react with C. pneumoniae. These findings suggest that chlamydiae should be periodically screened for Mycoplasma contamination. Careful attention to primer design is important if PCR is chosen as the screening method.

Base Sequence↗

PubMed2000

Mastitis, polyarthritis and abortion caused by Mycoplasma species bovine group 7 in dairy cattle.

OBJECTIVE: To report an outbreak of mastitis, polyarthritis and abortion caused by Mycoplasma sp bovine group 7 in three large, centrally-managed dairies and to review the relevant literature. DESIGN: Epidemiological, clinical and laboratory data were analysed, collated and reported. Multidisciplinary procedures were employed. These included clinical assessment and comprehensive laboratory investigations of affected calves, aborted foetuses and milk samples. Mycoplasma cultures and genetic analyses of isolates were undertaken to identify the aetiological agent. RESULTS: About 30% of 240 calves usually kept in a calf rearing facility developed severe polyarthritis as a result of Mycoplasma sp bovine group 7 infection between 2 and 3 weeks of age. Multiple abortions occurred on these farms. Mycoplasma sp bovine group 7 was recovered from the fibrinopurulent synovial exudates of four 14-day-old calves, from the stomach contents and lungs of two aborted foetuses, from 14 of 21 bulk milk and four of 10 mastitic quarters. Three bulk colostrum samples cultured during the outbreak were negative for mycoplasma. CONCLUSION: Mycoplasma sp bovine group 7 caused significant economic losses as a result of polyarthritis, abortion and mastitis. The disease probably originated from udder infections with spread being facilitated by the decreased use of tetracycline in the treatment of mastitis. Neonatal calves were most likely infected by the consumption of milk contaminated with the organism. Abortions presumably resulted from mycoplasmaemia. This appears to be the first report in Australia of bovine abortion resulting from Mycoplasma sp infection.

Abortion, Veterinary↗

PubMed1964

AEROSOLS AS A SOURCE OF WIDESPREAD MYCOPLASMA CONTAMINATION OF TISSUE CULTURES.

Mycoplasma isolates were cultured from 15 antibiotic-free cell cultures obtained from a single laboratory. Complement-fixation tests showed that these isolates were antigenically related to each other but were unrelated to M. hominis type 1, M. hominis type 2, M. arthritidis, M. laidlawii type B, Mycoplasma sp. H.Ep. #2 (Barile), or M. salivarium. Examination of serum used to feed the infected cell lines revealed no Mycoplasma. Infection resulting from cross-contamination by a single Mycoplasma strain from one cell culture to another was investigated. Although the organisms were not found in the air over the work area, aerosols containing these contaminants were produced in tissue culture bottles during the trypsinization of cell monolayers. The minimal infectious dose of Mycoplasma for tissue cultures was measured, and it was determined that one organism was capable of initiating an infection in a tissue culture. The pattern of contamination and the small dose required for infection indicated that Mycoplasma contamination was spread from one tissue culture to another via aerosols. It was demonstrated that Mycoplasma can be transferred from one cell culture to another through the use of a common burette for dispensing medium.

Aerosols↗

PubMed1975

Alterations in the metabolism of hamster tracheas in organ culture after infection by virulent Mycoplasma pneumoniae.

Exposure of hamster tracheal rings in organ culture to virulent Mycoplasma pneumoniae organisms leads to alterations in macromolecular biosynthesis and metabolic activity of the respiratory epithelial cells. Avirulent organisms derived from the same parent strain do not produce these effects. During the course of infection by virulent mycoplasmas, tracheal rings show an initial increase in [14C]galactose uptake followed by a significant decline as infection progresses which is also accompanied by abnormal processing of galactose as evidenced by amounts of 14CO2 released. Parallel decreases in the rate of [3H]orotic acid and [3H]amino acid uptake are observed. Within 24 h after infection of tracheal rings by virulent mycoplasmas, inhibition of host cell ribonucleic acid and protien synthesis is evident. Ribonucleic acid synthesis in infected cells, analyzed by gel electrophoresis, is reduced by 80% at 48 h and is negligible by 96 h. The course of mycoplasma infection can be interrupted or reversed by erythromycin after the initial mycoplasma-host cell interaction since addition of erythromycin 24 h or earlier after infection prevents the onset of abnormal orotic acid uptake. However, 48 h after infection, rescue of host cells by erythromycin cannot occur and cytopathology becomes evident. These data suggest that mediation of host cell injury requires continued protein synthesis by attached mycoplasmas, and the primary effect of mycoplasma infection on tracheal organ culture may be at a transcriptional or translational level.

Animals↗

PubMed2025

Robust and highly efficient transformation method for a minimal mycoplasma cell.

UNLABELLED: Mycoplasmas have been widely investigated for their pathogenicity, as well as for genomics and synthetic biology. Conventionally, transformation of mycoplasmas was not highly efficient, and due to the low transformation efficiency, large amounts of DNA and recipient cells were required for that purpose. Here, we report a robust and highly efficient transformation method for the minimal cell JCVI-syn3B, which was created through streamlining the genome of Mycoplasma mycoides. When the growth states of JCVI-syn3B were examined in detail by focusing on such factors as pH, color, absorbance, colony forming unit, and transformation efficiency, it was found that the growth phase after the lag phase can be divided into three distinct phases, of which the highest transformation efficiency was observed during the early exponential growth phase. Notably, the transformation efficiency of up to 4.4 × 10-2 transformants per cell per microgram of plasmid DNA was obtained. A method to obtain several hundred to several thousand transformants with less than 0.2 mL of culture with approximately 1 × 107-108 cells and 10 ng of plasmid DNA was developed. Moreover, a transformation method using a frozen stock of transformation-ready cells was established. These procedures and information could simplify and enhance the transformation process of minimal cells, facilitating advanced genetic engineering and biological research using minimal cells. IMPORTANCE: Mycoplasmas are parasitic and pathogenic bacteria for many animals. They are also useful bacteria to understand the cellular process of life and for bioengineering because of their simple metabolism, small genomes, and cultivability. Genetic manipulation is crucial for these purposes, but transformation efficiency in mycoplasmas is typically quite low. Here, we report a highly efficient transformation method for the minimal genome mycoplasma JCVI-syn3B. Using this method, transformants can be obtained with only 10 ng of plasmid DNA, which is around one-thousandth of the amount required for traditional mycoplasma transformations. Moreover, a convenient method using frozen stocks of transformation-ready cells was established. These improved methods play a crucial role in further studies using minimal cells.

Transformation, Bacterial↗

PubMed1972

Occurrence and properties of lactic dehydrogenases of fermentative mycoplasmas.

Eight fermentative mycoplasmas differing in genome size, deoxyribonucleic acid (DNA) base composition, or sterol dependence were examined for lactic dehydrogenase composition by spectrophotometric assay and polyacrylamide gel electrophoresis. Three completely different patterns of lactic dehydrogenase composition were found. (i) A nicotinamide adenine dinucleotide (NAD)-dependent l(+)-lactic dehydrogenase was found in Mycoplasma pneumoniae, M. gallisepticum, M. mycoides var. mycoides, mycoplasma UM 30847, M. neurolyticum, and Acholeplasma axanthum. Electrophoresis of cell-free extracts of each of these mycoplasmas produced, with the exception of M. mycoides var. mycoides and UM 30847, single, different enzyme bands. M. mycoides var. mycoides and UM 30847 were similar and formed multiple bands of enzyme activity. We were unable to establish whether these multiple bands were due to lactic dehydrogenase isoenzymes or artifacts. (ii) An NAD-dependent d(-)-lactic dehydrogenase which could not be reversed to oxidize lactate was found in M. fermentans. (iii) A. laidlawii A possessed an NAD-independent d(-)-lactic dehydrogenase capable of reducing dichlorophenol-indophenol, and an NAD-dependent l(+)-lactic dehydrogenase which is specifically activated by fructose-1,6-diphosphate. Heretofore, this enzyme regulatory mechanism was known to occur only among the Lactobacillaceae. No yeast-type lactic dehydrogenase activity was found in any of the mycoplasmas examined. The stereoisomer of lactic acid accumulated during growth correlated perfectly with the type of NAD-dependent lactic dehydrogenase found in each mycoplasma. The types of lactic dehydrogenase activity found in these mycoplasmas were not related to genome size, DNA base composition, or sterol dependence.

Cell-Free System↗

PubMed1965

CYTOPATHOGENIC MYCOPLASMAS ASSOCIATED WITH TWO HUMAN TUMORS. I. ISOLATION AND BIOLOGICAL ASPECTS.

Armstrong, D. (The Children's Hospital of Philadelphia, Philadelphia, Pa.), G. Henle, N. L. Somerson, and L. Hayflick. Cytopathogenic mycoplasmas associated with two human tumors. I. Isolation and biological aspects. J. Bacteriol. 90:418-424. 1965.-Mycoplasmas were isolated from cell cultures of two benign human tumors. The first isolate contained two mycoplasmas, one a well-known human species (Mycoplasma hominis type I) and frequent tissue culture contaminant, and the other a recently reported new type. The second isolate was a mycoplasma of the newly described type. The mycoplasmas could be reisolated, after one or more passages through tissue culture, from extracts of the original tumor tissue. The relationship of the organisms to the neoplasms remains obscure. Both isolates produce cytopathic effect (CPE) and acidification of medium in a variety of tissue cultures. The CPE may be diminished, but not abolished, by increasing concentrations of arginine in the tissue culture media. Infection of various tissue cultures with the mycoplasmas did not result in interference to super-infection with vesicular stomatitis virus.

Animals↗

PubMed2005

Systemic disease in Vaal rhebok (Pelea capreolus) caused by mycoplasmas in the mycoides cluster.

In the winter of 2002, an outbreak of mycoplasma infection in Vaal rhebok (Pelea capreolus) originating from South Africa occurred 15 weeks after their arrival in San Diego, Calif. Three rhebok developed inappetence, weight loss, lethargy, signs related to pulmonary or arthral dysfunction, and sepsis. All three rhebok died or were euthanized. Primary postmortem findings were erosive tracheitis, pleuropneumonia, regional cellulitis, and necrotizing lymphadenitis. Mycoplasmas were detected in numerous tissues by electron microscopy, immunohistochemistry, and PCR. The three deceased rhebok were coinfected with ovine herpesvirus-2, and two animals additionally had a novel gammaherpesvirus. However, no lesions indicative of herpesvirus were seen microscopically in any animal. The rheboks' mycoplasmas were characterized at the level of the 16S rRNA gene, the 16S-23S intergenic spacer region, and the fructose biphosphate aldolase gene. Denaturing gradient gel electrophoresis was carried out to address the possibility of infection with multiple strains. Two of the deceased rhebok were infected with a single strain of Mycoplasma capricolum subsp. capricolum, and the third animal had a single, unique strain most closely related to Mycoplasma mycoides subsp. mycoides large-colony. A PCR survey of DNA samples from 46 other ruminant species demonstrated the presence of several species of mycoplasmas in the mycoides cluster, including a strain of M. capricolum subsp. capricolum identical to that found in two of the rhebok. These findings demonstrate the pervasiveness of mycoplasmas in the mycoides cluster in small ruminants and the potential for interspecies transmission and disease when different animal taxa come in contact.

Animals↗

PubMed2004

Mycoplasma otitis in California calves.

A retrospective study of Mycoplasma otitis in California calves submitted for necropsy between 1993 and 2002 was conducted to characterize the demographic features of the disease and the pathologic findings associated with infection. Sixty-one confirmed cases of Mycoplasma otitis were identified among 20,525 necropsied cattle. All affected animals were calves, ranging in age from 2 weeks to 4 months and with a median age of 1.5 months. Ninety-two percent of the cases were dairy breeds. A higher percent of necropsied calves with Mycoplasma otitis were males (0.45%) than females (0.23%). The proportion of cases that had Mycoplasma otitis increased from 1993 to 2002, and there was a significant (P < 0.05) seasonal distribution, with the highest proportion in the spring and the lowest in the summer months. Infections involved both the middle and inner ear and were characterized by a suppurative inflammatory response with extensive bony involvement. Three species of Mycoplasma were isolated from the ears: M. bovis, M. bovirhinis, and M. alkalescens. Concurrent pneumonia occurred in 47 cases (77%), and Mycoplasma was isolated from the lungs of 30 of those cases. The increasing proportion of Mycoplasma otitis cases in the past 10 years emphasizes the importance of identifying risk factors that could be modified to lower the incidence of this disease in calves.

Age Factors↗

PubMedDate not supplied

Prevalence of mycoplasma antibodies in lesser prairie-chicken sera.

Serologic testing by the serum plate agglutination (SPA) procedure was performed to detect the presence of cross-reacting antibodies to Mycoplasma meleagridis, Mycoplasma synoviae, and Mycoplasma gallisepticum in lesser prairie-chickens (Tympanuchus pallidicinctus) trapped over a 2-yr period in Finney and Kearny counties of southwestern Kansas. Sera examined from birds (n = 50) obtained in March-April 2000 tested positive for M meleagridis, M. synoviae, and M. gallisepticum at levels of 6%, 10%, and 10%, respectively, for the population examined. Mycoplasma meleagridis antibodies were detected in 3 samples (2.7%), M. synoviae antibodies in 2 samples (1.7%), and M. gallisepticum antibodies in 3 samples (2.7%) from birds (n = 112) collected in March-April 2001. Data obtained by SPA can result in false positives and should be verified by additional procedures such as the hemagglutination-inhibition test. Low amounts of sera prohibited this additional testing. Thus, the positive SPA results should be considered presumptive for the presence of Mycoplasma antibodies. Although Mycoplasma antibodies have been detected in wild turkeys (Meleagris gallopavo) from Kingman and Butler counties in Kansas, this report is the first of possible mycoplasmosis in Finney and Kearny counties, Kansas. All birds testing positive by this procedure should be considered as potential carriers of Mycoplasma and should not be used in relocation efforts.

Agglutination Tests↗

PubMed2006

Subcellular structures of mycoplasmas.

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.

Adhesins, Bacterial↗

PubMed1998

Absence of mycoplasmal gene in malignant mammalian cells transformed by chronic persistent infection of mycoplasmas.

Chronic persistent infections by mycoplasmas induced malignant transformation of C3H mouse embryo cells that normally had never been reported to undergo spontaneous transformation. This mycoplasma-mediated oncogenic process had a long latency (more than 7 weeks of continuous mycoplasmal infection) and showed a multistage progression characterized by reversibility (at least up to 11 weeks of mycoplasmal infection) and irreversibility of malignant properties upon removal of the mycoplasma from culture. Further prolonged infections (18 weeks) by Mycoplasma fermentans or M. penetrans resulted in permanent transformation of these C3H cells that no longer required the continued presence of the transformation-inducing mycoplasmas in cultures to retain their malignant properties. Previous studies of viral oncogenesis revealed that virus-transformed cells always had viral gene(s) present. Integration of viral gene(s) apparently played an important role in the process of oncogenesis. In this study, we examined if the continued presence of any mycoplasmal gene(s) in mammalian cells, in whatever form, was also crucial in causing malignant cell transformation. Representational difference analysis (RDA) was a recently developed powerful technique to compare differences between two complex genomes. In the RDA system, subtractive and kinetic enrichment was used to purify and isolate restriction endonuclease gene fragment(s) of mycoplasmal origin, presumably present only in mycoplasma-transformed C3H cells, but not in nonmycoplasma-exposed control C3H cells. After three rounds of subtractive hybridization following PCR enrichment for each of three different restriction enzymes DNA digests, no gene fragment of mycoplasmal origin was amplified or identified in the permanently transformed C3H cells. Differing from tumorigenesis in animal cells induced by most oncogenic viruses or in plant cells induced by Agrobacteria, mycoplasmas evidently did not cause malignant transformation by integrating their gene(s) into the mammalian cell genome.

Animals↗

PubMed1992

Serological and microbial survey of Mycoplasma gallisepticum in wild turkeys (Meleagris gallopavo) from six western states.

From 1986 to 1989, sera from wild turkeys (Meleagris gallopavo), including three subspecies (M. gallopavo intermedia, M. gallopavo merriami and M. gallopavo mexicana) trapped in six western states were tested for antibody to Mycoplasma gallisepticum (MG) (n = 724), M. synoviae (MS) (n = 461) and M. meleagridis (MM) (n = 354) using the rapid plate agglutination (RPA) assay. Subsamples of these sera were also evaluated using the hemagglutination inhibition (HI) assay for antibody to MG (n = 664) and MS (n = 403). Attempts were made to isolate mycoplasmas by swabbing the trachea and cloaca of 190 live wild turkeys and from various tissues (sinus, nasal turbinates, trachea, lung, ovaries and oviduct) from 76 turkeys at necropsy. Isolates were identified using an immunobinding assay. Seroprevalence of MG, MS and MM in the RPA test was highly variable among years and geographic sites, ranging from 0 to 85%, 0 to 87%, and 0 to 83%, respectively, for each mycoplasma species. Of the 724 wild turkey sera tested, 200 (28%) were positive using the RPA assay, while only 20 (3%) of 664 sera tested using the HI assay were positive (at a titer greater than/= 1:80) for antibody to MG. Of the 461 sera tested 178 (39%) were RPA positive for MS, whereas none of the 403 samples tested by HI were positive for MS. Antibody to MM was detected in 72 (20%) of 354 turkey sera tested by RPA. Mycoplasmas were cultured from 81 (30%) of 266 wild turkeys, including 48 that were sampled live and 33 that were examined by necropsy. Mycoplasmas were isolated from every population in which culture was attempted. M. gallopavonis (MGP) was isolated from 37 (46%) of 81 birds which yielded mycoplasma, representing seven of 12 populations sampled. MG was isolated from lower respiratory tissues of one Rio Grande wild turkey trapped in Texas. M. synoviae was isolated from five of 16 Merriam's wild turkeys trapped in Arizona. Sera of birds from which MG or MS was isolated were positive to the respective antigen in the RPA test, but were negative by the HI assay. The RPA test was effective in identifying MG and MS infected turkeys despite lack of confirmation by the HI test. These data suggest that apparently healthy wild turkeys can carry pathogenic mycoplasmas and the currently used field test (RPA) can identify culture positive wild turkeys. Serological screening using the RPA test should be conducted on all wild turkeys prior to relocation.

Age Factors↗

PubMed1995

The occurrence of mycoplasmas in selected wild North American waterfowl.

We determined the prevalence of mycoplasma infection in breeding mallard (Anas platyrhynchos) and canvasback (Aythya valisineria) hens and their broods from the central United States (1988 to 1990); and wintering American black duck (Anas rubripes) and mallard hens from the eastern United States (1990 to 1993). Mycoplasmas were isolated by culturing tracheal swabs from 656 live birds and tissue samples from 112 dead waterfowl. Nine (18%) of 51 mycoplasma isolates were identified as Mycoplasma anatis; M. anatis was recovered from four mallards, a black duck, and a gadwall (Anas strepera) duckling. Nineteen (37%) of 51 mycoplasma isolates were identified as Mycoplasma cloacale; these isolates were obtained from mallard, canvasback, and black duck adults, and from a mallard duckling. Additional unspeciated mycoplasmas were isolated from mallards, black ducks, and one canvasback.

Animals↗

PubMed1975

Recent progress in mycoplasma research.

Today, 12 years after the identification of Eaton agent as a mycoplasma, much new information on this infection has accumulated. Better methods have become available, which will be helpful in determining whether other mycoplasmas might be human pathogens, e.g., some ureaplasmas in nongonococcal urethritis. Experimental mycoplasma infections in birds and animals have revealed common features with immune complex diseases in man. They may serve, therefore, as useful models for human mycoplasma disease. However, the most important finding in recent mycoplasma research has been the isolation of mycoplasma viruses. Viruses belonging to three different groups have been discovered. It will be interesting to study whether the virus determines the pathogenicity of mycoplasmas or not.

Acholeplasma laidlawii↗