- Volume 25, Issue 3, 1975

Two lists of phytopathogenic Pseudomonas species are presented. The first list comprises 80 names of species that have been validly published and for which cultures are available. It is proposed that these names be retained until a comprehensive rational classification is produced for this group. The second list contains more than 140 names which it is proposed should be rejected on grounds of illegitimacy, synonymy, lack of authentic cultures, or inappropriate classification.

Taxonomic relationships between various species of Bacillus were studied, using 52 test strains of 8 species, by deoxyribonucleic acid (DNA)-DNA hybridization and by testing transformability of the auxotrophic and antibiotic resistance genetic markers. Results for species identification by the conventional taxonomic method described in Bergey's Manual (8th ed., 1974) showed good agreement with the DNA-DNA hybridization data for B. licheniformis (16 strains), B. pumilus (one strain), B. coagulans (three strains), B. megaterium (three strains), B. cereus (one strain), and B. brevis (one strain). However, data for 16 of 27 test strains of B. subtilis and related species indicated lower homology indexes (20 to 25%) to the Marburg strain. Transformation of the auxotrophic markers to the wild type in the Marburg strain by DNA prepared from those strains showing lower homology to the Marburg strain was not detected, whereas the antibiotic resistance markers were transformed with the same DNA preparation. Transformation of the antibiotic resistance markers to the Marburg strain by DNA prepared from some strains of species other than B. subtilis, e.g., B. licheniformis and B. pumilus, was also detected, whereas transformation of the auxotrophic markers was not. These results strongly suggest that these two groups of B. subtilis should be divided into two different species. However, evidence suggesting the existence of a core region of DNA among a wide variety of species of Bacillus was presented.

Thin-layer chromatography of the ethyl ether-ethanol-soluble fraction after incubation with [35 S]methionine is useful for differentiation among mycobacterial species. Scanning of the radioactivity on chromatograms showed various distribution patterns of radioactive spots, and the patterns were, in most cases, characteristic for the species.

The unidentified streptococci from plants are catalase negative, gram positive, usually lanceolate cells occurring in pairs and short chains. More than one-half of the 505 strains investigated conform generally to the description of Streptococcus faecium, but many deviate in one or more of Sherman's characteristics, growth on bile-esculin agar, and acidification of milk. A few strains superficially resemble Streptococcus lactis. The strains not termed S. faecium-like are heterogeneous in adherence to Sherman's characteristics, growth and pigmentation on tellurite andtetrazolium agars, and the heme peroxidase reaction; 35 fermentation patterns were established from the fermentations of arabinose, raffinose, melezitose, melibiose, mannitol, and sorbitol. The diversity in properties indicatesthat the cultural reactions do not permit definitive characterization or speciation. It is suggested that the S. faecium-like strains have provided the ancestral pool from which the species as now described has become adapted to life within the animal host.

The deoxyribonucleic acid (DNA) of the mycoplasma Thermoplasma acidophilum has a base composition of 46 mol% guanine plus cytosine (G+C). Depurination can occur to the DNA in the culture conditions, giving rise to a product of lower buoyant density. This effect probably accounts for earlier descriptions of a much lower G+C content in the DNA. The size of the T. acidophilum genome, as measured by DNA renaturation, was 30% the size of the Escherichia coli genome.

An amended description of Micrococcus nishinomiyaensis Oda 1935 is proposed on the basis of a taxonomic analysis of 32 strains isolated from human skin. Strain CCM 2140 (= OUT 8094 = M. Oda no. 59) is the type strain of M. nishinomiyaensis Oda 1935.

An amended description of Micrococcus agilis Ali-Cohen 1889 is proposed on the basis of a taxonomic study of five strains. Strain ATCC 966 (= CCM 2390 = NCTC 7509) is designated as the neotype strain of M. agilis Ali-Cohen 1889.

Three subspecies of Bacteroides melaninogenicus differ from one another in cell wall composition, malate dehydrogenase mobility, deoxyribonucleic acid base composition, and physiological tests.

It is generally accepted that, except for two biotypes of Shigella flexneri 6 (the Manchester and Newcastle biotypes), all members of the genus Shigella are anaerogenic. Two bacterial isolates are described which have O antigens identical to those of S. boydii 13 and which cannot be distinguished biochemically from typical strains of that biotype except by their ability to produce gas from glucose and other fermentable substances. The relationship between these strains and the typical S. boydii 13 is analogous to that between strains of the Manchester biotype and the typical S. flexneri 6.