tsJT60, a cell cycle G0-ts mutant, becomes lethal at non-permissive temperature by transformation with adenovirus 5 when the expression of E1B gene is lacking

tsJT60, a temperature-sensitive (ts) mutant cell line of Fischer rat, is viable at both permissive (34 degrees C) and non-permissive (39.5 degrees C) temperatures. The cells grow normally in exponential growth phase at both temperatures, but when stimulated with fetal bovine serum (FBS) from G0 phase they re-enter S phase at 34 degrees C but not at 39.5 degrees. When tsJT60 cells were transformed with adenovirus (Ad) 5 wild type, they grew well at both temperatures, expressed E1A and E1B genes, and formed colonies in soft agar. When tsJT60 cells were transformed with Ad5 dl313, that lacks E1B gene, the transformed cells grew well at 34 degrees C but failed to form colony in soft agar. They died very soon at 39.5 degrees C. 3Y1 cells (a parental line of tsJT60) transformed with dl313 grew well at both temperatures, although neither expressed E1B gene nor formed colonies in soft agar. The phenotype of being lethal at 39.5 degrees C of dl313-transformed tsJT60 cells was complemented by cell fusion with 3Y1BUr cells (5-BrdU-resistant 3Y1), but not with tsJT60TGr cells (6-thioguanine resistant tsJT60). These results indicate that the lethal phenotype is related to the ts mutation of tsJT60 cells and also to the deletion of E1B gene of Ad5.     

Ribonucleic Acid Dependent Ribonucleic Acid Replicase in the Immune Response

An immune ribonucleic acid (iRNA) preparation was made using phenol extracts of spleens of mice previously immunized with Salmonella tennessee flagella. An enzyme, also prepared from the spleens of these mice, induced the incorporation of ³H-UTP into the acid-insoluble fraction in a cell-free system in the presence of this RNA. The enzyme activity could be demonstrated from the spleens of immunized mice but not from normal ones, and this activity was also inhibited by two derivatives of rifamycin. Treatment with ribonuclease or heating at alkaline pH resulted in a loss of activity in added RNA. The ³H-uridine-labeled product was found resistant to ribonuclease treatment but became sensitive when the product was subjected to heat treatment. However, actinomycin D, mitomycin C or bleomycin A₂ did not inactivate the enzyme activity. These results suggest that this enzyme induces the incorporation of UTP into the acid-insoluble fraction using iRNA as a template and the product may be a newly synthesized RNA which forms a hybrid with iRNA. This enzyme activity may play a role in the antibody formation process, and may account for the in vivo replication of iRNA by this enzyme, viz., probably an RNA-dependent RNA replicase.     

Transfer Agent of Immunity

An immune ribonucleic acid (RNA) was extractable from the spleen cells of mice hyperimmunized with live vaccine of Salmonella enteritidis. The RNA was capable of inducing cellular immunity and developing cellular antibody in the peritoneal macrophages of mice injected with this agent. It was found that cellular immunity was detectable even 90 days after injection in the peritoneal macrophages of mice which had received an intraperitoneal injection with this agent. Results of serial passive transfers of cellular immunity through immune RNA led us to the conclusion that this agent does not contain antigen or fragment thereof and may replicate actively in the recipient cells, although the mechanism still remains to be elucidated. The development of cellular immunity by immune RNA was inhibited by puromycin but not by actinomycin D. However, serial passive transfers of cellular immunity through immune RNA was inhibited by treatment of recipient mouse with actinomycin D, implying the role of DNA-dependent RNA polymerase in the processing of immune RNA in recipient cells. Using these results, the role of immune RNA and the possible mechanisms of immune RNA replication are discussed.     

Ultrastructure of the parathyroid gland of the japanese lizard in the spring and summer season

The ultrastructure of the parathyroid glands of adult Japanese lizards (Takydromus tachydromoides) in the spring and summer season was examined. The parenchyma of the gland consists of chief cells arranged in cords or solid masses. Many chief cells contain numerous free ribosomes and mitochondria, well-developed Golgi complexes, a few lysosome-like bodies, some multivesicular bodies and relatively numerous lipid droplets. The endoplasmic reticulum is mainly smooth-surfaced. Cisternae of the rough endoplasmic reticulum are distributed randomly in the cytoplasm. Small coated vesicles of 700-800 Å in diameter are found occasionally in the cytoplasm, especially in the Golgi region. The chief cells contain occasional secretory granules of 150-300 nm in diameter that are distributed randomly in the cytoplasm and lie close to the plasma membrane. Electron dense material similar to the contents of the secretory granules is observed in the enlarged intercellular space. These findings suggest that the secretory granules may be discharged into the intercellular space by an eruptocrine type of secretion. Coated vesicles (invaginations) connected to the plasma membrane and smooth vesicles arranged in a row near the plasma membrane are observed. It is suggested that such coated vesicles may take up extracellular proteins. The accumulation of microfilaments is sometimes recognized. Morphological evidence of synthetic and secretory activities in the chief cells suggests active parathyroid function in the Japanese lizard during the spring and summer season.     

L-Galactono-{gamma}-Lactone Dehydrogenase: Partial Characterization, Induction of Activity and Role in the Synthesis of Ascorbic Acid in Wounded White Potato Tuber Tissue

The total initial vitamin C content (23 mg%) of sliced whitepotato tuber tissue incubated at 20°C decreased slightlyduring the first 12 h and increased thereafter by 80% duringa 48-h incubation. The ascorbic acid (AsA) content (21 mg%)decreased slightly during the first 12 h and then increasedby 40% within 36 h and slowly decreased thereafter. The levelof dehydroascorbic acid (DHA) was low initially, being only2 mg% at 36 h it started to increase and reached 10 mg% at 48h. The activty of L-galactono-     

Distribution of hydraulic resistance in seedlings,sprouts and an adult tree ofPasania edulis Makino

Hydraulic resistance is an important factor in predicting water status. Hydraulic resistance of petiols, stems and branches, and roots was measured inPasania edulis Makino in order to compare the distribution of resistance between current seedlings, current stump sprouts and a 16 year old adult tree. Total resistance showed only minor variations despite large variations in plant size. This result is thought to be consistent with allometry between leaf mass and supportive organ mass, and with changes in permeability of conductive organs. Root resistance was low in sprouts and the adult tree due to their mature root systems. Current seedlings with undeveloped root systems had high root resistance. The proportion of petiol resistance in total resistance was high compared to the proportion of their conductive distance, and was thought to be a limiting factor of tree water status. The petiol resistance of the adult tree leaves was higher than for seedling and sprout leaves. From a comparison with the leaf water relation characteristics, the petiol resistance was thought to be provided as low values for intolerant leaves against water stress in order to compensate water inflow, and high values for tolerant leaves to regulate water inflow.