Buoyant density and hybridization analysis of human DNA sequences, including three satellite DNAs.

Total human DNA was fractionated from the three types of Cs2SO4 gradient used to prepare satellites I, II and III. Three satellite DNAs were found: satellite I with a mean buoyant density of 1.6888 g/ml comprising about 1.

Physical analysis of a (dG + dC)-rich fraction of DNA obtained from the ovine genome.

Using the organomercuric compound 3,6-bis(acetatomercurimethyl)dioxane in conjunction with Cs2SO4 density gradient equilibrium centrifugation a (dG + dC)-rich DNA fraction constituting 10% of the ovine genome was separated from the remainder. Further fractionation allowed four distinct classes of DNA to be identified with buoyant densities in neutral CsCl of 1.714, 1.

A physical study of the ovine genome.

The ovine genome has been divided into some seventy-five fractions using 3,6-bis(acetatomercurimethyl)dioxane (BAMD) in conjunction with Cs2SO4 density-gradient-equilibrium centrifugation. Distinct macromolecular populations detected have buoyant densities in CsCl of 1.700, 1.

Determination of the relatedness of the soluble surface proteins of Trypanosoma brucei and Paramecium aurelia.

The soluble surface proteins isolated by Cross (1975) from Trypanosoma brucei are compared to those which occur on Paramecium aurelia. Calculations based on the amino acid residue data and the molecular weights of these surface antigens indicate that there is a considerable degree of similarity between the T. brucei and the P.

The in vivo effect of dimethyl sulphoxide (DMSO) on protein synthesis and the polyribosome profile in Paramecium.

When Paramecium tetraurelia in log phase growth is treated with 4% dimethyl sulphoxide (DMSO) for five minutes the amount of polyribosomes is reduced 3- to 4-fold while there is a corresponding increase in 80s ribosomal material. Reducing the concentration of DMSO to 1% allows immediate reversal of the condition. Paramecium polyribosomes subjected to 4% DMSO either in whole cell homogenates or during purification through sucrose density gradients appear unaffected while cycloheximide at concentrations up to 100 mug/ml did not prevent DMSO from exerting its effect in vivo.

Genetically controlled specific immunological unresponsiveness.

Evidence is presented that in rabbits and mice a relatively simple genetic mechanism exists which controls the animals' ability to produce antibody against bovine serum albumin.