Deoxyribonucleic Acid Base Composition in Yeasts

The deoxyribonucleic acid base composition of 15 species of yeasts was determined to obtain further clues to or supporting evidence for their taxonomic position. Species examined belonged to the genera Saccharomyces, Debaryomyces, Lodderomyces, Metschnikowia, and Candida. The range of moles per cent guanine plus cytosine (GC content) for all yeasts examined extended from 34.9 to 48.3%. The sporogenous species and the asporogenous yeasts spanned the range with 36.6 to 48.3% GC and 34.9 to 48% GC, respectively. Three Saccharomyces species (S. rosei and related species) exhibited significantly higher GC contents than S. cerevisiae, whereas the fermentative species D. globosus revealed a%GC more aligned to the S. rosei group than to the nonfermentative D. hansenii. Similar GC contents were demonstrated by L. elongasporus and its proposed imperfect form C. parapsilosis. The range of GC contents of various strains of three Metschnikowia species studied was 6.1%, with the type strain of M. pulcherrima having the highest GC content (48.3%) of all of the yeasts examined.     

Deoxyribonucleic Acid Base Composition of Stentor coeruleus*

SYNOPSIS. The deoxyribonucleic acid of Stentor coeruleus has of 33 moles percent guanine plus cytosine. a buoyant density in CsCl of 1.692 gcm^?3 and a base composition of 33 moles percent guanine plus cytosine.     

Deoxyribonucleic Acid Base Composition of the Genus Lactobacillus

Deoxyribonucleic acids of 45 strains of Lactobacillus and 5 strains of Bifidobacterium which had been analyzed for base composition by chromatographic means were examined at equilibrium in a CsCl density gradient. Regression analysis showed that there have been systematic errors involved in the estimation of guanine plus cytosine (GC) content by the chemical method, and that the relation between buoyant density and base composition is indeed linear and best fitted by the equation GC = 10.309 (rho-1.662), which compares well in slope with the equation of Schildkraut, Marmur, and Doty. With the improved data obtained in this study, the specific groupings of the species of both genera were reevaluated.     

Base Composition of Deoxyribonucleic Acid Isolated from Athiorhodaceae

Guanine plus cytosine content of deoxyribonucleic acid ranged from 60.5 to 65.0% for five Rhodospirillum species and from 64.4 to 70.3% for six Rhodopseudomonas species. These values were compared to those of two Hyphomicrobiaceae and two hydrogen-oxidizing bacteria.     

Deoxyribonucleic Acid Base Composition in the Taxonomy of Staphylococcus

Twenty-four strains of Staphylococcus aureus, including eight known mutants of S. aureus and strains growing under a variety of environmental conditions or exposed to a number of physical and chemical agents, maintained a remarkably narrow range of guanine plus cytosine (GC) content (32.4 to 35.1%). The wide range of GC content (30.7 to 40%) reported in the literature was due to the variety of methods and calculations used rather than to any substantial variation in base composition. The UV-2 "mutant" (ATCC 13680) with a GC content of 67.6% reported to be derived from S. aureus (ATCC 13679) was a species of Corynebacterium. The data presented were consistent with the concept that base composition changes only to a very slight degree by mutation.     

Deoxyribonucleic Acid Base Composition and Homology Studies of Leptospira

Four distinct genetic groups of leptospiras were demonstrated among selected pathogenic and "biflexa" serological types. Pathogenic leptospiras could be divided into two groups on the basis of per cent guanine + cytosine (GC) in their deoxyribonucleic acid (DNA). One group had 36 +/- 1%, the other 39 +/- 1%. The biflexa strains had DNA of 39 +/- 1% GC, but were further separated into two groups on the basis of DNA-annealing tests. Strains within groups had a high degree of specific duplex formation (75% binding or more with reference to the homologous DNA). There was little or no genetic relatedness between strains of the four groups (less than 10% DNA homology). The thermal elution midpoint of heterologous DNA duplexes was always lower than the homologous reaction. The serological relationships among strains were not meaningful in terms of relatedness determined by specific duplex formation.     

Deoxyribonucleic Acid Base Composition of Some Cellular Slime Molds*

SYNOPSIS. Deoxyribonucleic acids (DNAs) isolated from 12 representatives of cellular slime molds grown in monoxenic cultures were analyzed by density gradient centrifugation in CsC1. The unique contribution of the DNA of each food organism was subtracted and the DNA base composition of each cellular slime mold determined. The guanine plus cytosine contents range 22–37 moles % within the representatives of the order. Minor bands (satellite bands) of DNA have been observed in preparations from Dictyostelium spp. and from Polysphondylium pallidum.     

Deoxyribonucleic Acid Base Composition of Lactobacilli Determined by Thermal Denaturation

Moles per cent guanine plus cytosine content of 16 lactobacilli provided three taxonomic groups: I, 32.4 to 38.3% with five species; II, 42.7 to 48.0% with six species; III, 49.0 to 51.9% with five species.     

Deoxyribonucleic Acid Base Composition and Biochemical Properties of Certain Coagulase-Negative Enterotoxigenic Cocci

Eight coagulase-negative, enterotoxigenic strains of cocci and one weakly coagulase-positive strain isolated from a number of different sources, including cases of food poisoning incidents, were evaluated for their relationship to Staphylococcus aureus on the basis of deoxyribonucleic acid (DNA) buoyant density and physiological studies. One strain of cocci produced enterotoxins A and C, two strains produced types B and C, four strains produced only type C, and one strain only type D. The enterotoxin produced by one strain of cocci was serologically untypable. None of the test organisms produced detectable amounts of enterotoxin in broth cultures. The test strains of cocci exhibited the following profile: all produced catalase; all grew anaerobically and fermented glucose; five were sensitive to lysostaphin; the percentage of guanine plus cytosine content of their DNA varied from 32.7 to 37.6; five produced acid from mannitol both aerobically and anaerobically; two formed δ-hemolysin; five produced phosphatase and acetoin; and all produced heat-stable nuclease. None of the organisms exhibited typical characteristics of S. aureus, S. epidermidis, or S. saprophyticus. On the basis of the present data and data reported elsewhere, these organisms should be considered as variants or mutants of S. aureus.     

Deoxyribonucleic Acid Base Composition of Rothia dentocariosa as Determined by Thermal Denaturation

The moles per cent guanine plus cytosine (GC) of 10 filamentous strains of Rothia dentocariosa ranged from 65.4 to 69.7. Major differences were not observed in the base composition of a filamentous form (69.7 moles% GC) and its coccal variant (68.0 moles% GC).     

Deoxyribonucleic Acid Base Composition of Species in the Yeast Genus Kluyveromyces van der Walt emend. van der Walt

The deoxyribonucleic acid base composition (percent guanine + cytosine [GC]) was determined for 29 strains, representing 18 species of the genus Kluyveromyces. It was concluded that on the basis of GC content (47.4%) and other properties K. veronae occupies an uncertain position in the genus Kluyveromyces. The GC content of the remaining 17 species ranged from 35.3 to 43.4%, and three groups of species were recognized. The GC content of the first ranged from 35.3 to 38.0%; that of the second group from 39.5 to 41.7%; that of the third group from 42.4 to 43.4%. Several species revealed a nearly identical GC content. The GC contents do not correspond in all instances with the five groups of species proposed by van der Walt.     

Deoxyribonucleic Acid Base Composition of Some Members of the Subgenera Betabacterium and Streptobacterium

The base composition of deoxyribonucleic acid (DNA) prepared from four Betabacterium strains and four Streptobacterium strains was determined. Per cent GC values (guanine + cytosine/total bases) of the DNA were evaluated from the “melting-temperatures” (Tm) of the nucleic acids. For the Betabacterium strains, these values ranged from 44 to 51.5% GC, and those for the Streptobacterium strains ranged from 43 to 47.5% GC. The taxonomic division into these two subgenera is not, therefore, supported by these findings.     

Deoxyribonucleic Acid Base Composition of Flavobacteria and Related Gram Negative Yellow Pigmented Rods

DNA base composition analyses on 35 Gram negative yellow pigmented rods indicated two distinct groups. The larger contained 29 strains with G + C contents of between 30·8 and 39·5% and comprise 19 non-gliding, aflagellate strains and 10 gliding strains. The smaller, a heterogenous collection of six strains, had G + C contents in the 51·4–63% range.     

Agreement Between Deoxyribonucleic Acid Base Composition and Taxometric Classification of Gram-Positive Cocci.

Silvestri, L. G. (Università Statale, Milan, Italy), and L. R. Hill. Agreement between deoxyribonucleic acid base composition and taxometric classification of gram-positive cocci. J. Bacteriol. 90:136-140. 1965.-It had been previously proposed, from taxometric analyses, that gram-positive, catalase-positive cocci be divided into two subgroups. Thirteen strains, representative of both subgroups, were examined for deoxyribonucleic acid (DNA) base composition, determined from melting temperatures. Per cent GC (guanine + cytosine/total bases) values fell into two groups: 30.8 to 36.5% GC and 69 to 75% GC. Strains with low per cent GC values belonged to the Staphylococcus aureus-S. saprophyticus-S. lactis taxometric subgroups, and those with high per cent GC values belonged to the S. roseus-S. afermentans subgroup. The hypothetical nature of any classification is emphasized, and, in the present work, the hypothesis derived from taxometric analyses of division into two subgroups is confirmed by the study of DNA base ratios. The two subgroups correspond, respectively, to the genera Staphylococcus and Micrococcus.