Manley Mandel

Plus and Minus Single-Stranded DNA Separately Encapsidated in Adeno-Associated Satellite Virions

Based on physical and chemical determinations, the mnolecular weight of the type 4 adeno-satellite virus is 5.4 X 106 daltons, and the virion contains 1.4 X 106 daltons of DNA. Denaturation and renaturation studies indicate that the viral genome is a single-stranded DNA molecule and that each virion contains either a minus or a plus strand. Upon extraction, the minus and plus strands unite to form double-stranded DNA molecules with no obvious excess of unpaired strands.

Buoyant densities of DNA of mammals

One characteristic of DNA, CsCl buoyant density peak values, was determined for DNA samples isolated from 93 species belonging to 11 orders of mammals. The CsCl buoyant density values varied over a very narrow range, 1.696–1.701 g/cm3. Satellite DNAs were found in a number of species. The function and origin of these satellite DNAs are not known.

Enterobacter gergoviae sp. nov.: a new species of Enterobacteriaceae found in clinical specimens and the environment.

The name Enterobacter gergoviae sp. nov. is proposed for a group of organisms isolated from various clinical sources in France, Africa, and the United States and from environmental sources. E. gergoviae deoxyribonucleic acid contains 60% guanine plus cytosine. Deoxyribonucleic acid relatedness studies showed E. gergoviae strains to be very highly related, as is characteristic of strains of a single species. The biochemical profiles of E. gergoviae strains were extremely similar. Phenotypically, E. gergoviae belongs to the family Enterobacteriaceae and is most similar to Enterobacter aerogenes. E. gergoviae is distinguishable from E. aerogenes by its positive urea reaction and negative reactions for KCN, sorbitol, mucate, and gelatinase. Strain CIP 76.01 (= ATCC 33028 = CDC 604-77) is the type strain of this new species.

Comparative Zone Electrophoresis of Enzymes in the Genus Bacillus

Extracts from 88 strains representing a wide variety of Bacillus species were examined by zone electrophoresis, followed by specific stains for each of 11 enzyme activities, and were also analyzed for deoxyribonucleic acid (DNA) buoyant density. Strains representing B. megaterium, B. cereus, B. laterosporus, B. firmus, B. alvei, B. polymyxa, and B. macerans exhibited unique patterns of enzyme migrations for each species. Most strains of B. subtilis and B. amyloliquefaciens also displayed characteristic enzyme migration patterns for each species. However, one strain, B. subtilis KA63, resembled B. amyloliquefaciens in DNA composition and enzyme types. It was previously reported to resemble B. amyloliquefaciens in DNA-DNA homology. Another group of strains, which was homogeneous and distinctive in electrophoretic enzyme types, included two strains of B. subtilis subsp. niger and one of B. subtilis subsp. globigii. Yet another group contained the type strains for B. licheniformis, B. pulvifaciens, and B. coagulans. A second B. coagulans strain was quite different from that in the above-mentioned group or from any other Bacillus strain examined. Strains of B. pumilus fell into two distinct biotypes according to the electrophoretic data; culturally, they comprised a homogeneous set. Representatives of B. thuringiensis, B. bombycis, and B. entomocidus were not distinguishable from B. cereus by these data.

Isolation and characterization of DNA from fixed cells and tissues

Abstract DNA was isolated from cultured mammalian cells, liver tissue and Escherichia coli after treatment with the common laboratory fixatives for various periods of time. The cultured cells included the mouse cell strain LM and the Chinese hamster cell strain Don C. Liver tissue was obtained from young adult Chinese hamsters. Ultraviolet spectral absorbance ratios, CsCl buoyant density determinations, melting curves and hyperchromicity were used to characterize the DNA samples. Recovery of “normal” DNA was excellent with most fixatives, but not when formalin was used. Formalin fixation interfered with the isolation procedure, and when DNA was extracted the buoyant densities in CsCl were significantly different from the DNA extracted from unfixed materials, but the Tm values were not different.

Deoxyribonucleic acid base compositions of hyphomicrobia

SummaryThe deoxyribonucleic acids of 70 hyphomicrobia were examined at equilibrium in neutral CsCl density gradients. The guanine plus cytosine (%G+C) content was estimated to range from 59.2 to 66.8% G+C. The strains could be divided into three groups with different base composition of their DNA; 61.0±1.1%, 64.1±0.6%, and 66.5±0.6% G+C. The values are compared with those for the base composition of DNA of a number of phototrophic, budding bacteria.

Deoxyribonucleic acid base composition of Simonsiellaceae.

The molar percentages of guanine plus cytosine in the DNA of 51 strains of Simonsiellaceae were determined by buoyant density ultracentrifugation of cell lysates in CsCl. The DNA base ratios ranged from 41–55 mole-% guanine plus cytosine. These values fall within the range known for the Order Cytophagales, the non-fruiting gliding bacteria, and are out-side the range of the Order Myxobacterales, the fruiting myxobacteria. Among the strains of the genus Simonsiella, four distinct groups can be delineated on the basis of source of origin (sheep, dog, cat, human) and GC content. The neotype of Alysiella filiformis has a GC content of 45.4 mole-%.

Deoxyribonucleic Acid Base Composition and Nucleotide Distribution of Pedomicrobium spp.

Summary The DNAs of seven bacterial strains belonging to Pedomicrobium ferrugineum and P. manganicum were investigated by buoyant density centrifugation and thermal denaturation experiments. The DNA base composition was calculated to range from 66.3 to 67.3% GC in CsCl gradients and from 64.8 to 65.7% GC in thermal transition profiles. The correlation of both methods was T mo.issc = 428.5 (ϱ — 1.533) under our experimental conditions. Analysis of the DNA nucleotide distributions revealed a homogeneous group characterized by Gaussian distribution with a mean width of 9.19 ± 0.14% GC (uncorrected) and an average degree of asymmetry of 1.16 ± 0.04.

Heterogeneity in CsCl buoyant densities of chiropteran DNA

The CsC1 buoyant densities of D N A from most mammalian species fall within a narrow range, from 1.696 to 1.701 g/cm 3 (Arrighi et aL, 1970). Generally, no significant difference was found among orders or among subdivisions of an order. The present study reports a significant difference in CsC1 buoyant density of D N A observed between the two suborders of the order Chiroptera (bats): Megachiroptera (one family, 38 genera, 154 species) and Microchiroptera (19 families, 173 genera, 875 species) (Koopman and Cockrum, 1967). The collection data of the animals, the tissue sources used for D N A extraction, and the locations of the voucher specimens are listed in Table I. D N A was isolated either by a modified Marmur s method (Marmur, 1961) or by the procedure of Arrighi et al. (1968). Buoyant densities of all D N A samples from megachiropteran and a few of the microchiropteran specimens were determined three separate times in a model E analytical ultracentrifuge; all others were run twice. The buoyant densities of all chiropteran species determined thus far are presented in Table I. It can be seen that species belonging to the suborder Megachiroptera possess a lower buoyant density than those belonging to the suborder Microchiroptera. The individual determinations ranged from 1.694 to 1.697 for Megachiroptera and from 1.696 to 1.702 for Microchiroptera. Thus the upper values for Megachiroptera were the lower values for Microchiroptera. When the values for each species were averagedl the range for Megachiroptera was from 1.6947 to 1.6960 and that for Microchiroptera from 1.6977 to 1.7005. Although the difference appears small, it is a highly significant

Similarity of genetic distance determined from DNA thermal denaturation profiles to standard estimates of bacteriophage relatedness

High resolution thermal denaturation profiles of a series of potentially related bacteriophages of Bacillus subtilis contain a multitude of distinctive features that permit them to be divided into at least four groups. In addition, the profiles can be used to derive the quantitative parameter, genetic distance, defined by Soumpasis (Soumpasis, D. (1980) J. Theor. Biol. 86, 137-147). Both the quantitative and the qualitative intercomparisons of profiles are in general agreement with the results of standard techniques for estimating genetic relatedness.