Internal proteins of bacteriophage T4D: Their characterization and relation to head structure and assembly

Three basic proteins of low molecular weight (about 8000, 10,000 and 18,000) were isolated from the T4D phage particle. Many molecules of each protein are located within the phage head, possibly in association with the DNA, and together with the proteins which form the head membrane comprise most of the head structural protein. The purified internal proteins were characterized by physicochemical and immunological techniques; a radio-immunoassay allowed measurement of their synthesis in phage infected bacteria. Each internal protein is synthesized at both early and late times after infection. Their structural genes are present in the phage genome, but do not appear to be among the known amber mutant-containing genes of T4D. No evidence was found to suggest that the internal proteins are formed from a common precursor molecule, nor are their origins related to those of the internal peptides; however, one of the internal proteins may be altered before its incorporation into the phage. Pulse-chase experiments with two of these proteins show that they are incorporated into certain defective T4D heads. Whether or not they are incorporated appears to depend on the degree of completion of these heads, perhaps with respect to DNA packaging.     

Photosynthetic CO(2) Fixation Products and Activities of Enzymes Related to Photosynthesis in Bermudagrass and Other Plants

After a 5-second exposure of illuminated bermudagrass (Cynodon dactylon L. var. `Coastal') leaves to ¹⁴CO₂, 84% of the incorporated ¹⁴C was recovered as aspartate and malate. After transfer from ¹⁴CO₂-air to ¹²CO₂-air under continuous illumination, total radioactivity decreased in aspartate, increased in 3-phosphoglyceric acid and alanine, and remained relatively constant in malate. Carbon atom 1 of alanine was labeled predominantly, which was interpreted to indicate that alanine was derived from 3-phosphoglyceric acid. The activity of phosphoenolpyruvate carboxylase, alkaline pyrophosphatase, adenylate kinase, pyruvate-phosphate dikinase, and malic enzyme in bermudagrass leaf extracts was distinctly higher than those in fescue (Festuca arundinacea Schreb.), a reductive pentose phosphate cycle plant. Assays of malic enzyme activity indicated that the decarboxylation of malate was favored. Both malic enzyme and NADP⁺-specific malic dehydrogenase activity were low in bermudagrass compared to sugarcane (Saccharum officinarum L.). The activities of NAD⁺-specific malic dehydrogenase and acidic pyrophosphatase in leaf extracts were similar among the plant species examined, irrespective of the predominant cycle of photosynthesis. Ribulose-1, 5-diphosphate carboxylase in C₄-dicarboxylic acid cycle plant leaf extracts was about 60%, on a chlorophyll basis, of that in reductive pentose phosphate cycle plants.     

Effect of actinomycin D and guanidine on the formation of a ribonucleic acid polymerase induced by foot-and-mouth-disease virus and on the replication of virus and viral ribonucleic acid

The RNA-dependent RNA polymerase induced in baby-hamster kidney cells by infection with foot-and-mouth-disease virus can be detected as early as 60min. after infection, which is 60min. before viral RNA synthesis commences. The time at which the polymerase can first be detected coincides with the latest time at which actinomycin D (50mug./10(7) cells) or guanidine (1mg./10(7) cells) inhibits virus replication. However, by increasing the concentration of guanidine, viral replication can be inhibited later in the growth cycle, casting doubt on the validity of the hypothesis that guanidine acts specifically on the formation of the viral RNA polymerase.     

Skin Collagen and Thickness in Women with Hirsuties

Total skin collagen is greatly increased in women with hirsuties. This is presumably due to androgen, whether locally produced or circulating.