Soil bacteria: numerical analysis of electrophoretic protein patterns developed in acrylamide gels

The protein band patterns of 47 soil bacteria, all thought to be of the arthrobacter kind, were analyzed by a simple numerical method in which each observed Et value was treated as a unit character. The results were not satisfactory. In a second analysis only major bands were taken into account and small variations in the Et values of the 24 chosen bands were disregarded. This subjective editing was required to satisfy a minimum criterion that replicates be recognized as such by the analysis. It was concluded that without a means of estimating the variation in Et value for each band and of identifying homologous bands, electrophoretic band patterns of crude extracts of soluble proteins are likely to be of limited rather than general use in microbial taxonomy.

Soil bacteria: a principal component analysis and guanine-cytosine contents of some arthrobacter-coryneform soil isolates and of some named cultures

A two-stage principal component (P.C.) procedure was applied in a comparison of the nature and properties of 19 named cultures of Arthrobacter and 77 arthrobacter–coryneform soil isolates: cultures of Brevibacterium linens, Nocardia cellulans, Corynebacterium michiganense, and Jensenia canicruria were also studied. These cultures were characterized in terms of their reaction to a set of 98 tests. Deoxyribonucleic acid (DNA) was isolated from 55 of the cultures and the moles % guanine + cytosine (% GC) content determined by thermal denaturation and ultracentrifugation methods. The P.C. analysis resulted in the recognition of 13 groups of cultures. Twelve of the Arthrobacter cultures (representing nine species) were contained in two groups, one of which contained only Arthrobacter cultures. Arthrobacter citreus, A. duodecadis, A. flavescens, and A. terregens were contained in another group with 13 soil isolates. Arthrobacter simplex and A. tumescens were located in separate groups which also included B. linens and N. cellulans respectively; otherwise these groups contained soil isolates. C. michiganense was located in a group of four soil isolates which was spatially related to the two groups of Arthrobacter cultures. Twenty-five characteristics were considered important for differentiating the groups of cultures and they were concerned with nutritional requirements, use of carbon compounds, catalase production, nitrate reduction, antibiotic sensitivity, and the Gram reaction. Most of the named Arthrobacter cultures were located in groups which were separated from the groups of the soil isolates. The DNA of the 55 cultures examined contained from 40 to 74% GC: for 32 of these cultures the GC content of DNA was between 59 and 66% and for 19 cultures the GC content was between 66 and 74%. With few exceptions cultures grouped together by the numerical method had similar GC contents.

Phospholipids of Nocardia coeliaca

The lipids of Nocardia coeliaca were separated into at least 10 components by the use of thin-layer chromatography. Phosphatidylcholine was the most abundant phospholipid in this organism, accounting for 25 to 40% of the total phospholipids. The major fatty acid components of the phosphatidylcholine were 14-methyl-pentadecanoic acid (41%), the other C(15) and C(17) iso- and anteiso-fatty acids (29%), and palmitic acid (13.5%). The next most abundant phospholipid was phosphatidylethanolamine (25 to 30%), followed by phosphatidylinositol (11 to 14%) and cardiolipin (7 to 15%). Phosphatidylethanolamine and phosphatidylinositol were very similar to the phosphatidylcholine in fatty acid composition, whereas cardiolipin was characterized by a higher content of palmitic acid (30%). In all of the phospholipids examined, only trace amounts of monounsaturated fatty acids were present. When washed cells of N. coeliaca were incubated with methionine-methyl-(14)C for 1 to 3 hr, the radioactivity was mainly incorporated into the choline moiety of the phosphatidylcholine. In contrast, acetate-1-(14)C or glycerol-1-(14)C was incorporated much more slowly into the phosphatidylcholine than into the other phospholipids and neutral lipids. No phosphatidylcholine was detected in 10 other species of Nocardia examined.

Characterization of deoxyribonucleic acids from streptomycetes and nocardiae

The relationships among selected streptomycetes, nocardiae, and mycobacteria have been determined, based upon the base composition of their deoxyribonucleic acid (DNA) and upon the ability of their denatured DNA to anneal with single-stranded reference DNA. The streptomycetes constituted a homogeneous group whose DNA contained between 69 and 73 mole% guanine + cytosine (% GC). Moreover, the streptomycetes examined showed 37 to 88% homology with the Streptomyces venezuelae and S. rimosus reference DNA. The nocardial and mycobacterial DNA both contained 62 to 69% GC. The nocardial strains studied fell into either a 62 to 64% GC group or a 68 to 69% GC group, indicating that they should not be assigned to a single species. The nocardiae having 68 to 69% GC showed 24 to 44% homology with S. venezuelae reference DNA. In competition experiments, wherein unlabeled heterologous DNA interfered with binding of labeled homologous DNA, the nocardial DNA with 68 to 69% GC showed a greater degree of homology with the streptomycetes than did the nocardial DNA with 62 to 64% GC. In addition, the DNA from spores of S. venezuelae was cursorily examined, and interactions between S. venezuelae denatured DNA and polyribonucleotides were sought. The buoyant density of the DNA from S. venezuelae spores was distinctly less than that from mycelia. Moreover, denatured S. venezuelae DNA formed a dense complex with polyriboguanylate.