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At least 19 recordsLinked to original sources
PubMed1979

Alteration of colonial morphology of Acholeplasma laidlawii and Acholeplasma modicum by infection with Mycoplasmatales viruses.

Morphologically aberrant colonies resulted from the infection of Acholeplasma laidlawii with two of its three known viruses and from Acholeplasma modicum cells naturally carrying virus. The patterns of colonial alteration differed between cells infected with the two A. laidlawii viruses. Colonies derived from single cells infected with the bullet-shaped virus MV-L1 (Mycoplasmatales virus-laidlawii-1) had a radial sectoring pattern of intracolonial swellings ("blebs"), whereas cells infected with the tailed icosahedral virus MV-L3 contained bubble-like blebs. Colonies from cellsinfected with the enveloped virus MV-L2 appeared identical to those obrained from uninfected cells. Aberrant colonies contained 10(6) colony-forming units of organisms and 10(6) plaque-forming units of virus serologically identical to the infecting type, indicating that both the virus and host organism were capable of simultaneous replication. Enumeration of virus by means of counting aberrant colonies was 30-fold more sensitive than infectious center assay for MV-L1 and 1.2- to 2-fold higher for MV-L3. Furthermore, blebbed colonies plaquing with a new virus specific to A. modicum. Thus, blebbing in colonies provides a valuable marker for detection of the Mycoplasmatales viruses.

Acholeplasma↗
PubMed1972

Transfection mediated by Mycoplasmatales viral DNA.

DNA isolated from Mycoplasmatales viruses MVL51 and MVGs51 was infectious when mixed with Acholeplasma laidlawii BN1-Na1(R) cells. Infectivity was destroyed by deoxyribonuclease but not by ribonuclease, Pronase, or specific antiserum to the virus. Host mycoplasma cells were only competent for transfection during late-log growth phase. The rates of the establishment of DNase insensitivity of viral DNA transfectants were similar to those of bacteriophage systems. The dose-response curve for transfection suggested that an average of six molecules of DNA must interact with a cell in order to produce one infectious center. Mycoplasmatales virus DNA exhibited a low efficiency of infection; one infectious center required 4 x 10(5) virus equivalents of DNA.

Bacteriophages↗
PubMed1984

Immunoblotting for determination of the antigenic specificities of antibodies to the Mycoplasmatales.

Determination of the nature of antigens towards which specific antibodies are directed has caused great difficulties in studies of the antigenic structure of the Mycoplasmatales. In immunoblotting, polypeptides are separated first by SDS polyacrylamide gel electrophoresis and transferred to cellulose nitrate electrophoretically. The resultant pattern is stained by enzyme-linked staining techniques. This permits direct detection of the antigenic specificities recognized by human and animal immune serum. For example, human convalescent sera from patients with Mycoplasma pneumoniae pneumonia recognize 2 to 7 polypeptides in M. pneumoniae, whereas human sera from patients with postpartum fever from whom Ureaplasma urealyticum has been isolated from the bloodstream detect 15 to 25 polypeptides. A comparison of M. pneumoniae with M. genitalium using rabbit antisera demonstrated that these two organisms show strong cross-reactions, although the organisms can be distinguished. Although certain antigens (epitopes) are destroyed in the procedure, it appears that about two-thirds of the polypeptides retain antigenicity. Immunoblotting provides a powerful means for identifying and subsequently fractionating antigens important to the human immune response.

Antibodies, Bacterial↗
PubMed1980

Differentiation of mycoplasmatales from bacterial protoplast L-forms by assay for penicillin binding proteins.

Membrane proteins with the specific ability for binding penicillin with high affinity (penicillin binding proteins) were found to be present in two strains of the cell wall-less protoplast L-form of P. Mirabilis and were absent from different species of Mycoplasma and from Acholeplasma laidlawii. Thus, the assay for penicillin binding proteins appeared to be suitable for the differentiation of the cell wall-less procaryotes. The absence of penicillin binding proteins from the mycoplasmatales further confirmed the unrelatedness of this group to the bacteria.

Acholeplasma laidlawii↗
PubMed1975

Characterization of Mycoplasmatales virus-laidlawii 3.

Purified preparations of Mycoplasmatales virus-laidlawii 3 were negatively stained and studied by electron microscopy. They were seen to consist of uniform sized particles having a polyhedral head, 57 nm by 61 nm, and a short tail, 25 nm long, joined to the head at one vertex by a collar. The particles were shown to have buoyant densities of 1-477 g/ml in CsC1, 1-32 g/ml and 1-26 g/ml in potassium tartrate and a sedimentation coefficient, S20,W, OF 290 +/- 13. They are composed of 35-2% double-stranded DNA and five structural polypeptides with approximate mol. wt. of 172000, 81000 73000, 68000 and 43000. The classification of the virus from its morphology and chemical properties is discussed.

Acholeplasma laidlawii↗
PubMed1977

Heterogeneity among strains of Mycoplasmatales virus-laidlawii 2.

Five isolates of Mycoplasmatales virus-laidlawii 2 (MV-L2) derived from bovine strains of Acholeplasma laidlawii were shown to differ in host range, plaque morphology and neutralization tests with MV-L2 antiserum. Cross-testing using virus resistant clones of A. laidlawii confirmed the heterogeneity of this group. Adaptation of viruses to sub-optimal host was demonstrated.

Acholeplasma laidlawii↗
PubMed1976

Microcalorimetric detection of growth of Mycoplasmatales.

A static ampoule microcalorimeter was used to study the growth of mycoplasmas, acholeplasmas and ureaplasmas. Growth as indicated by thermograms was compared with the results of conventional methods, namely, terminal dilution counts, plate counts, turbidimetric measurements, glucose consumption and pH changes. Removal of oxygen had little effect on mycoplasma growth. The microcalorimetric method is potentially useful for identifying and enumerating the members of the Mycoplasmatales.

Acholeplasma↗
PubMed1971

Isolation of Mycoplasmatales viruses and characterization of MVL1, MVL52, and MVG51.

Eleven Mycoplasmatales viruses are now known. Burst size, burst time, sensitivity to ultraviolet and the host range of three viruses that were studied are different. However, all three are naked, rod-shaped particles of similar size. Plaque morphology and the isolation of immune cells suggest that both virulent and nonvirulent infections are possible.

Bacteriophages↗
PubMed1978

Induction of a pH-stable interferon in sheep lymphocytes by Mycoplasmatales virus MVL2.

The data presented in this report show that the enveloped Mycoplasmatales virus MVL2 is capable of interferon induction in sheep peripheral blood lymphocytes. The phenomenon was dose dependent, requiring approximately 10(8) plaque-forming units of virus per 2 X 10(6) lymphocytes. The interferon was stable to pH 2.0 treatment, was produced in moderately high levels (greater than 1,000 units), and met many of the criteria for classification as a type I interferon. Heat-inactivated MLV2 lost its ability to induce interferon, whereas ultraviolet-inactivated virus retained its capacity to induce levels comparable to untreated virus. Whereas the MVL2 used in these studies was contaminated with several host cell proteins as determined by sodium dodecyl sulfate-containing polyacrylamide gel electrophoresis, the contaminants probably did not play a role in the induction because isolated cell membranes or soluble cell contents from Achoplasma laidlawii are inactive as inducers. Also presented in this report is a preliminary description of the structural polypeptides of MVL2.

Acholeplasma laidlawii↗
PubMed1977

Purification and partial characterization of the principal deoxyribonucleic acid polymerase from Mycoplasmatales.

In this report we present the first description of the isolation and partial characterization of the deoxyribonucleic acid (DNA) polymerase activity from two species of Mycoplasmatales, Mycoplasma orale type 1 and M. hyorhinis. We have identified only a single DNA polymerase species in the mycoplasma crude extracts, and the enzymes from the two organisms are very similar in their structural and enzymatic properties. The purified polymerase from each source has a specific activity of greater than 50,000 U/mg of protein, a sedimentation coefficient of 5.6s, and an estimated molecular weight by gel filtration of 130,000. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the most highly purified M. orale fraction contains a single major protein band of 130,000 daltons, which we believe may represent the polymerase protein. The enzymes are most reactive with gapped (activated) DNA and show a marked preference for this primer template over oligodeoxyribonucleotide-initiated homoribo- or homodeoxyribo-polymers. The most purified preparations are devoid of contaminating endonuclease activity and also appear to lack associated 5' leads to 3'- or 3' leads to 5'-exonuclease activities, as determined by highly sensitive assays. The absence of the 3' leads to 5'-exonuclease is particularly remarkable in that this activity is essentially ubiquitous among the DNA polymerases that have thus far been characterized from procaryotes.

Bacterial Proteins↗
PubMed1987

Comparison of two methods for detection of mollicutes (Mycoplasmatales and Acholeplasmatales) in cell cultures in the Netherlands.

A total of 1949 cell cultures was tested for contamination with mollicutes by cultivation on and in mycoplasma media, 25.7% of the cell cultures was positive, 243 strains of Mycoplasma hyorhinis were isolated. Furthermore, mainly M. arginini and M. orale were detected, less often Acholeplasma laidlawii, M. fermentans and M. pneumoniae. Optimal conditions for isolation were discussed. About one third of 217 hybridoma cultures and two third of 57 myeloma cultures proved to be contaminated, all with M. hyorhinis. A DNA fluorochrome staining method (DAPI-test) was compared to cultivation for testing 1039 cell cultures. The efficiency of the DAPI-test could be estimated to be about 96% that of cultivation about 89%, but cultivation is more specific. The highest assurance is obtained when both methods are applied.

Acholeplasma laidlawii↗
PubMed1977

Rapid biochemical tests for characterization of the Mycoplasmatales.

Methods are described for the rapid detection of beta-D-glucosidase and phosphatase in mycoplasma cultures using fluorogenic 4-methylumbelliferone substrates. These methods were applied to a selection of mycoplasma cultures and were compared with the conventionally used tests for these enzymes. Results were similar by both methods, but the fluorogenic tests could be read after 1 h, whereas the conventional tests took several days.

Acholeplasma↗
PubMed1979

Comparison of mycoplasmatales virus MV-Lg-pS2-L172 with plasmavirus MV-L2 and the other mycoplasma viruses.

Mycoplasma virus MV-Lg-pS2-L172 was sensitive to heat (56 degrees C/30 minutes), Nonidet-P40 and ether. In these respects it resembled Plasmavirus MB-L2. However, it differed from MV-L2 (and the other mycoplasma viruses, MV-L1, MV-L3 and BN1 virus) in reciprocal plaque inhibition and serum neutralization tests (MV-L2 only). By plaque formation on host lawns resistant to the different mycoplasma viruses, including MV-Lg-pS2-L172, this latter virus was shown to be distinct from the other viruses, including MV-L2. Both MV-Lg-pS2-L172 and MV-L2 possessed one polypeptide band (out of 10) that was not common to the heterologous virus.

Acholeplasma laidlawii↗