E. A. Freundt

Hybridization Experiments with Deoxyribonucleic Acid from Ureaplasma urealyticum Serovars I to VIII

Nucleic acid hybridization experiments performed with deoxyribonucleic acid from serovars (serotypes) I to VIII of Ureaplasma urealyticum revealed a clustering of the analyzed strains into two major groups. One cluster included serovars I, III, and VI and the other included serovars II, IV, V, VII, and VIII, the two groups being distinguished at the 40 to 60% homology level. No consistent correlation could be demonstrated between the nucleic acid homology data presented here and the heterologous serological relationships known to exist between different serovars of U. urealyticum. On the other hand, agreement was found between clusterings according to deoxyribonucleic acid homologies and recently published observations made by polyacrylamide gel electrophoresis methods.

Electrophoretic Analysis of Proteins from Mycoplasma hominis Strains Detected by SDS-PAGE, Two-dimensional Gel Electrophoresis and Immunoblotting

The proteins of 14 strains of Mycoplasma hominis were compared by SDS-PAGE in gradient gels, by two-dimensional (2D) gel electrophoresis of extracts of 35S-labelled cells and by immunoblot analysis of cell proteins. The strains examined included the M. hominis type strain PG21 and 13 others isolated variously from genital tract, mouth, blood, upper urinary tract and a wound. These 14 strains shared 76-99% of proteins in SDS-gradient gel analysis and 41-72% in the 2D gels. As expected, the immunoblot analysis likewise revealed the existence of an extensive common protein pattern in M. hominis, in addition to a number of antigens shared only by some strains.

Genome Size and Deoxyribonucleic Acid Base Composition of Thermoplasma acidophilum

The deoxyribonucleic acid base composition of two strains of Thermoplasma acidophilum including the type strain 122-1B2 was determined by buoyant density and thermal denaturation temperature. The guanine plus cytosine content of the two strains examined was found by both methods to be about 46%. This result is strikingly at variance with the significantly lower values, about 25%, reported by the group of workers who first described this organism. The genome size, as determined by the renaturation method of Wetmur and Davidson, was found to be about 109 daltons. This is identical with the genome size of members of the family Acholeplasmataceae, order Mycoplasmatales, within which order T. acidophilum has been tentatively classified.

Nucleic acid hybridization experiments withSpiroplasma citri and the corn stunt and suckling mouse cataract Spiroplasmas

Spiroplasma citri and two as yet unclassified mycoplasmas of the genusSpiroplasma, the corn stunt spiroplasma (CSS) and suckling mouse cataract agent (SMCA), were compared by determination of the guanine-plus-cytosine (G+C) content of the DNA and by nucleic acid homology studies. The G+C content ofS. citri, CSS, and SMCA was found to be 26.4, 25.1, and 30.3 mol%, respectively. In hybridization experiments between DNA extracted from the three organisms, a hybridization of 2–3% was demonstrated betweenS. citri and SMCA, while hybridization betweenS. citri and CSS was about 30%. It is concluded on the basis of these findings, together with avialable serological data, that SMCA can be classified as a separate new species of the genusSpiroplasma, but additional work will be required to clarify the status of the CSS.

Identity of cactus and lettuce spiroplasmas withSpiroplasma citri as determined by DNA-DNA hybridization

The isolation of spiroplasma strains from the cactusOpuntia tuna monstrosa and from aster yellows-diseased lettuce is described. DNA from these strains (ATCC 29594 and ATCC 29747) is compared with DNA fromSpiroplasma citri, and from the corn stunt and suckling mouse cataract spiroplasmas. The cactus and the lettuce isolates are found to be identical withS. citri by this method.

Genome size and deoxyribonucleic acid base composition of Anaeroplasma abactoclasticum, Anaeroplasma bactoclasticum, and a sterol-nonrequiring anaerobic mollicute

The genome sizes of the type strains of the sterol-requiring organisms Anaeroplasma abactoclasticum and Anaeroplasma bactoclasticum and of a sterol-nonrequiring obligately anaerobic mollicute, strain 161, were determined by the renaturation method of Wetmur and Davidson. The genome molecular weights of the three strains were almost identical (viz., approximately 109). This value is identical to the genome molecular weights of members of the family Spiroplasmataceae in the order Mycoplasmatales and of the family Acholeplasmataceae in the order Acholeplasmatales. The guanine-plus-cytosine contents of the deoxyribonucleic acids of A. abactoclasticum, A. bactoclasticum, and strain 161, as determined by the buoyant density method, were found to be 30.1, 32.8, and 39.9 mol%, respectively, thereby confirming results reported previously by other workers. The deoxyribonucleic acid base composition and genomic size are among the data needed to clarify the taxonomic status of the genus Anaeroplasma and of the sterol-nonrequiring anaerobic organism strain 161.

Ultrastructural changes in mollicutes induced by the peptide antibiotic herbicolin A.

Electron microscopy of negatively stained mycoplasma, ureaplasma, and acholeplasma cells showed ultrastructural changes after 10 min of treatment of the organisms with the peptide antibiotic herbicolin A in concentrations ranging from 10 micrograms/ml for Mycoplasma capricolum to 600 micrograms/ml for Ureaplasma urealyticum. The morphological changes were shown to be reversible at low concentrations of the antibiotic but irreversible at high concentrations. Images

Lack of genetic relatedness between Mycoplasma alvi and Mycoplasma sualvi

In hybridization experiments performed with deoxyribonucleic acids extracted from the type strains of Mycoplasma alvi and Mycoplasma sualvi, no hybridization was demonstrated. A representative strain (strain 1161-III) of a supposedly new species that exhibited some resemblance to M. alvi especially showed levels of deoxyribonucleic acid-deoxyribonucleic acid relatedness of less than 4% with both species.

NOTES: Lack of Deoxyribonucleic Acid-Deoxyribonucleic Acid Homology Between Thermoplasma acidophilum and Sulfolobus acidocaldarius

Deoxyribonucleic acids (DNAs) from the type strains of Thermoplasma acidophilum (strain 122-1B2) and Sulfolobus acidocaldarius (strain 98–3) are compared. The guanine-plus-cytosine contents of the DNAs are 45.0 and 39.9 mol%, respectively. DNA-DNA hybridization experiments show homologies slightly above the background level of 0.1% in the experiment.