Nature of the Ethylenediaminetetraacetic acid Requirement for Transformation of Bacillus subtilis with Single-Stranded Deoxyribonucleic Acid

The ethylenediaminetetraacetate (EDTA) requirement for transformation of Bacillus subtilis with single-stranded deoxyribonucleic acid (DNA) was examined. The results indicate that a chelating agent such as EDTA is a stringent requirement for transformation with single DNA strands only at nonsaturating DNA concentrations, and that EDTA, when required, must be present during several steps in the transformation process and appears to insure the survival of single-stranded DNA by rendering a nuclease in competent populations inactive.     

Correlation of Melting Temperature and Cesium Chloride Buoyant Density of Bacterial Deoxyribonucleic Acid

Samples of bacterial deoxyribonucleic acid from bacteria having guanine plus cytosine (GC) contents in the range of 27 to 72 moles per cent GC were analyzed by optical melting (T(m)) and equilibrium buoyant density methods. The relation between these properties is shown to be linear. The relative value of 1.99 moles per cent GC per degree C change in T(m) is calculated, and a reference method for the calculation of GC contents relative to a standard is derived.     

CTP SYNTHETASE ACTIVITY IN NEONATAL AND ADULT RAT BRAIN

—The activity of CTP synthetase (UTP:ammonia ligase (ADP-forming), EC 6.3.4.2) in adult and new-born rat brain was determined by an enzyme assay using [¹⁴C]UTP as a substrate. The activity was age-dependent and showed a distinctive distribution pattern between the cerebral hemispheres and cerebellum. The possible correlations between the activity of CTP synthetase and the rate of RNA or lipid biosynthesis, as well as the regulatory importance of the enzyme in the formation of cytidine nucleotides are discussed.