H(3)-labeled purified 16S and 23S ribosomal RNA's and transfer RNA's were found to hybridize exclusively with the H strand of the separated complementary strands of B. subtilis DNA. These results indicate that these RNA's are transcribed in vivo from a strand with a composition similar to that from which messenger RNA's are copied and presumably by the same mechanism.

Bacillus subtilis↗

PubMed1969

Ribosomal RNA genes in bacteria: evidence for the nature of the physical linkage between 16S and 23S RNA genes in Bacillus subtilis.

The nature of the arrangement of 16S and 23S ribosomal RNA genes on the Bacillus subtilis chromosome was studied by means of a Cs(2)SO(4) density gradient centrifugation technique after complexing DNA-(ribosomal) RNA hybrids with mercuric ions. It was observed that the same fragments of single-stranded DNA with an average molecular weight of 1.9 x 10(6) which hybridize with 23S RNA also hybridize with 16S RNA. This indicates that genes for both these species of ribosomal RNA are physically linked on such DNA fragments. Some evidence suggests that the two types of genes are interspersed with each other, perhaps in sets, each of which contains a 16S and a 23S ribosomal RNA gene.

Bacillus subtilis↗

PubMed1969

An ATP-dependent deoxyribonuclease from Escherichia coli with a possible role in genetic recombination.

A DNase which requires ATP for its function was purified from E. coli and some of the characteristics of the purified enzyme were studied. This enzyme activity could not be detected in certain (recB and recC) recombination deficient mutant strains. The possible role of the enzyme in genetic recombination is discussed.

Adenine Nucleotides↗

PubMed1969

Separation of T-even bacteriophage deoxyribonucleic acid from host deoxyribonucleic acid by hydroxyapatite chromatography.

A simple and rapid method is described for separation of T-even bacteriophage deoxyribonucleic acid (DNA) from host (Escherichia coli) DNA by hydroxyapatite column chromatography with a shallow gradient of phosphate buffer at neutral pH. By this method, bacteriophage T2, T4, and T6 DNA (but not T5, T7, or lambda DNA) could be separated from host E. coli DNA. It was found that glucosylation of the T-even phage DNA is an important factor in separation.

Carbon Isotopes↗

PubMed1969