- Volume 22, Issue 4, 1972

Twenty-six strains representing ten species of Erwinia were examined by deoxyribonucleic acid (DNA)-DNA hybridization techniques for relatedness to each other as well as to other members of the family Enterobacteriaceae, including the genera Escherichia, Salmonella, Klebsiella, Shigella, and Proteus. DNA homologies among the different Erwinia specieswere in most cases below 50%, even under nonstringent annealing conditions. In most instances DNA homologies between Erwinia species and Escherichia, Salmonella, Klebsiella, and Shigella species showed about the same amount of relatedness as in Erwinia-to-Erwinia combinations. The molecular hybridization data indicate that the genus Erwinia is a loosely composed group of bacteria that often have no greater affinities to each other than to other enteric bacteria. Furthermore, the data do not support some of the previously proposed taxonomic divisions within the genus Erwinia.

A collection of gram-negative, asporulating organisms, including corroding bacilli, was divided into four groups on the basis of a gas-liquid chromatographic analysis of the esters of their cellular fatty acids. Group I contains strains which produce hexadecanoicand octadecenoic acids as major constituents, with a lower percentage of 9-hexadecenoic acid and relatively small amounts of dodecanoic, tetradecanoic, and octadecanoic acids. Group II strains produce a large amount of octadecenoic acid and small amounts of hexadecanoic, dodecanoic, tetradecanoic, and octadecanoic acids. Strains placed in group III produced a large amount of an unidentified fatty acid, which appears to be unique to this group. Other fatty acids, including hexadecanoic, octadecanoic, and two additional unidentified acids, were produced in small amounts. Group IV contains strains which produce high contents of 9-hexadecenoic and hexadecanoic acids and a small amount of tetradecanoic acid.The facultatively anaerobic corroding organisms, including Eikenella corrodens (Eiken) Jackson and Goodman, fall into group I, whereas group II contains anaerobic strainswhich are distinct from each other as well as from the Bacteroides strains included in this study.

An amended description of Micrococcus luteus (Schroeter 1872) Cohn 1872, at present abroad-based species characterized primarily on negative characteristics, is proposed on the basis of a taxonomic analysis of 30 strains. CCM 169 (= ATCC 4698) is designated as the neotype strain of M. luteus.

The type of peptidoglycan in the cell wall and the ability to transform auxotrophic mutants of Micrococcus luteus ATCC 27141 were determined for 55 strains of micrococci and related organisms. There exists a perfect correlation between these characteristics. Onlystrains containing the unique peptidoglycan of M. luteus (l-Lys-peptide subunit)can participate in the genetic exchange, and it is suggested that all such strains be placed in the species M. luteus.

An amended description of Micrococcus varians Migula 1900 is given on the basis of a study of 20 strains. CCM 884 (= ATCC 15306 = NCTC 7564) is designated as the neotype strain of M. varians. Staphylococcus lactis Shaw et al. 1951 is a later objective synonym and Microccus pulcher Müller 1961 is a later subjective synonym of M. varians Migula 1900.

A moderately halophilic coccus is described which possesses morphological and physiological characteristics most nearly corresponding to those of members of the genus Micrococcus. The organism was isolated from unrefined solar salt and is a moderate halophile: no growth occurs in media without added NaCl, but good growth is observed in media containing 1 to 4 m NaCl or KCl. The characteristics of this organism are sufficiently discrete to suggest that it be placed in a new species, for which the name Micrococcus halobius is proposed. The type strain is 28-3 (= ATCC 21727).

Fifty-two Mycoplasma and Acholeplasma strains, including eight T-mycoplasmas, were tested for their susceptibility to optochin to determine the value of the test for differentiating between these organisms. Taxo-P discs showed a marked variation in their inhibitory effect from lot to lot and within each lot. They were found unsuitable, and wells withoptochin solution were used instead. Some difference in susceptibility to optochin was found not only between but also within the tested Mycoplasma and Acholeplasma species. The T-mycoplasmas appeared to be more resistant to optochin than the other mycoplasmas and the acholeplasmas. From the results of this study it is concluded that the optochin test isof very limited value in the characterization and identification of mycoplasmas and acholeplasmas.

The base compositions of the deoxyribonucleic acid and the genome sizes of eight serotypes of human T-mycoplasmas are reported. The guanine plus cytosine contents, as measured by thermal denaturation and CsCl gradient centrifugation, are 27 to 28%, the latter method giving slightly lower values. The genome sizes are within the range of 4.1 × 108 to 4.8 × 108 daltons, which corresponds to the values found for members of the family Mycoplasmataceae.

Fruiting bodies of representative genera of the order Myxobacterales Jahn 1915 were examined by using a “Stereoscan” electron microscope (Cambridge Instrument Co.). Speciesof Myxococcus. Chondrococcus. Melittangium. Chondromyces, Archangium, and Stigmatella were examined. The instrument was found to be of value in studying the detail of fruiting bodies.

The cell wall compositions of two strains of “true” nocardiae, Nocardia asteroides R 399 and N. caviae IM 1381, and two strains of “so-called nocardiae,” N. piracicabensis and N. mediterranei, were determined. Two different methods were used for preparing the cell walls. In the one, the bacteria were sonically treated, and the cell walls were obtained by differential centrifugation; in the other, the bacteria were delipidated before sonic treatment. The cell walls of true nocardiae contain nocardic acids, identified by comparison with nocardic acids isolated from the whole cell. The peptidoglycan structures of the “true” and “so-called” nocardiae studied showedsome important differences. In the true nocardiae, the glycan strand is constituted of bT-N-acetylglucosaminyl (1 > 4) N-glycolylmuramic acid, and muramic acid is N-acetylated in the strains of “so-called nocardiae,” as it is in the majority of bacteria. In addition, the peptide monomers of true nocardiae are diamidated on both the α-carboxyl group of d-glutamic acid and the (l) carboxyl group of meso-diaminopimelic acid, whereas the peptide monomers of the “so-called nocardiae” have only one amide substituent on the carboxyl group of meso-diaminopimelic acid. It is difficult to differentiate without ambiguity members of the genus Nocardia from the mass of the other actinomycetes which contain major amounts of meso-diaminopimelic acid. Our results suggest that true nocardiae may be those actinomycetes whose cell walls contain, in addition to arabinose and galactose, N-glycolylmuramic acid in the glycan part of the peptidoglycan and diamidated peptides in the peptide part of the peptidoglycan. In addition, truenocardiae contain nocardic acids.

A new species belonging to the genus Oerskovia Prauser et al. of the order Actionmycetales is described under the name O. xanthineolytica. It differs from O. turbata mainly in its ability to hydrolyze xanthine and hypoxanthine, in certain carbohydrate reactions, in the production of a phosphatase, and in its ability to grow at 42 C on Trypticase-soy agar. The type strain of this species is IMRU 3959 (LL G62) (=ATCC 27402). The description of the genus Oerskovia is emended to take into account the fact that members of this genus can grow anaerobically on Trypticase-soy medium with the production of catalase-negative biomasses.

This is the final major publication of a series describing the type or suggested neotype strains for a total of more than 450 species of actinomycetes. Type strains or suggested neotype strains for species previously placed in the genera Streptomyces, Actinomyces sensu Krasil&nikov, or Streptoverticillium have been obtained from original authors, culture collections, or other reliable sources for redescription by currently acceptable criteria and methods. More than 40 collaborating laboratories representing 18 nations have cooperated in establishing methods and criteria, in locating authentic type strains, and especially in laboratory studies required for the emendations to descriptions. Specimens of the redescribed type strains or suggested neotypes are deposited in the American Type Culture Collection, the Centraalbureau voor Schimmelcultures, the U.S.S.R. Research Institute for Antibioties. and the Institute for Fermentation, Osaka, Japan. This report adds descriptions for 158 additional species, completing the major work of the project. Additional type strains will be studied, described, and deposited in collections as they become available.

In an attempt to facilitate proper understanding by Japanese bacteriologists of the rules which govern the nomenclature of bacteria, a Japanese translation of the International Code of Nomenclature of Bacteria was made by Ochi et al. (3). Proposals are here made to change several of the Japanese characters in the translation which do not accurately convey the intended meaning.

(i) The Japanese terms “hyøjun” and “kijun,” used to translate the English term “type,” should not be used in the Japanese text of the Code because they may lead the Japanese reader to misunderstand the nomenclatural type concept.The English term “type” should be used in the Japanese Code without translation.

(ii) The Japanese term “keiyō-mei” was used t o translate the English term “epithet.” It should also be rejected because “keiyō-mei” may be understood by the Japanese reader as a word for “name.” “Keiyo-go” is proposed as a replacement for “keiy6-mei.”