Degradation of Streptococcal Cell Wall Antigens In Vivo

Specific chemical modification of group A polysaccharide antigen to the A-variant structure was demonstrated in the lymphoid organs of mice by autoradiography by use of radioantibodies specific for these structures. Both antigenic moieties persisted and were still discerned 10 weeks after injection of the group A cell wall. In rabbit skin, the group A specificity was altered after a prolonged period. Unlike the situation for the mouse, polysaccharide A was not converted to A-variant structure, but another specificity common to both polysaccharides persisted at the site of injection. Mucopeptide, separated from the polysaccharide of group A cell walls, was eliminated from the site of injection in rabbit skin between 4 and 8 hr after injection. Group D streptococcal cell walls were also rapidly eliminated from tissue, and were no longer detectable 8 hr after injection into rabbit skin or 24 hr after injection into mice. The rapid degradation of these structures was correlated with their susceptibility to lysozyme in vitro and was in contrast to the prolonged persistence of group A cell walls, which were completely resistant to egg white lysozyme. This persistence in tissue correlated with the capacity of group A cell wall fragments to induce a chronic inflammatory process, whereas the isolated mucopeptide or group D cell walls produced only an acute necrotoxic reaction.     

Inheritance of quantitative expression of erythrocyte glucose-6-phosphate dehydrogenase activity in the Negro—a twin study

Studies have been conducted on eight sets of monozygous and nine sets of dizygous female Negro twins, both members of whom were heterozygous for G-6-PD deficiency. Twins were studied both by assay of erythrocytic G-6-PD activity and by the methemoglobin elution test (MET). The MET is a procedure which identifies histochemically cells with appreciable G-6-PD activity and permits accurate determination of the percentage of such cells in heterozygotes. Monozygous twins showed significantly less within-pair variation than dizygous twins with both the MET and G-6-PD assay.Concerning the significantly greater agreement in MET results in monozygous twins than dizygous twins, our present working hypothesis is that X-chromosomal inactivation in the Negro female is genetically controlled, rather than random. However, certain alternate hypotheses allowing for random X-inactivation have not been excluded; these include somatic cell selection after random X-inactivation, and cell exchange between identical twins in utero/it. Studies in nontwin related heterozygotes now underway should help differentiate among these various possibilities.In addition to the studies on 17 pairs of female twins heterozygous for G-6-PD deficiency, 26 pairs of nondeficient female Negro twins have been studied by G-6-PD assay. Within-pair variation in monozygous twins was significantly less than within-pair variation in dizygous twins in all cases. The genetic influences detected with the G-6-PD assay in the female twins could theoretically be due to nonrandom X-inactivation, to genetically determined quantitative differences in enzyme activity (e.g., isoalleles), or to both. By appropriate calculations, based on the MET results, we have factored out the effects of X-inactivation on overall enzyme activity in the heterozygous deficient twins. After removal of the effect of X-inactivation, monozygous twins heterozygous for enzyme deficiency continue to show significantly less within-pair variation than dizygous twins. This finding indicates significant genetic influences on quantitative G-6-PD activity other than X-inactivation and other than the deficiency allele. This conclusion has been strengthened by studies on male twins where X-inactivation is not present.Supported by USPHS research grants AM-09381, HE-17544, AM-09919, and HE-03341, by USPHS Career Development Award 1-K3-AM-7959 (Dr. Brewer) and by U.S.A.E.C. Contract (11-1)-1552.     

The Isolation of Colicine V and a Study of Its Immunological Properties

Colicine V has been obtained from the culture medium in which the colicinogenic bacillus E. coli K357 L_T is grown. The material is electrophoretically homogeneous and proves to be a lipocarbohydrate protein complex identical with the type-specific O antigen of the parent bacillus. Colicine V is toxic both for mice and for rabbits and readily stimulates the elaboration of precipitins and bacterial agglutinins, as well as antibodies which neutralize the antibacterial activity of the colicine itself. The colicine is also toxic for certain strains of Enterobacteriaceae. Although colicine V and colicine K, previously described in this laboratory, have many properties in common, they exhibit no cross-serological relationship whatsoever.     

Some Seismic Profiles near the Western End of the Puerto Rico Trench

A cooperative program of seismic refraction profiling was completed in the vicinity of the Puerto Rico Trench by Hudson Laboratories, Woods Hole, Lamont, and Texas A. & M. Profiles completed near the western end of the Trench were analyzed at Hudson Laboratories. Five seismic layers are indicated below the water layer. The thickness/velocity relationships are as follows: 5.1 km of 1.5 km/sec. (water); 1 km of 1.7 km/sec. (sediment); 1.5 km of 3 km/sec. (metamorphics?); 2 km of 5.5 km/sec. (basement); and 2 km of 7.1 km/sec. (high speed basement). Below these, typical Moho velocities of 8.1 km/sec. were measured. Total depth to Moho ranges from 9 to 12 km below sea level, the greatest variation occurring in the basement layers. The least depth was measured 65 miles north of the Puerto Rico Trench.     

Chromosome structure in the dinophyceae

Summary A large number of cytochemical staining techniques together with chemical and enzymic extractions have been used on Prorocentrum micans. The object of this study being to ascertain the main chemical components of the unusual chromosomes found in the Dinophyceae.DNA was the only major component which could be positively determined and unlike most other chromosomes these appeared to contain no protein or RNA. However, the chromosomes were embedded in a granular proteinaceous nuclear matrix, the function of which is as yet unknown. The similarity in the composition and structure of the chromosomes of Prorocentrum and the nuclei of Bacteria are discussed.