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Biomedical subjects

F H Wilt

Publications and source records attributed to F H Wilt.

At least 55 records · Page 3Linked to original sources
PubMed1973

Polyadenylation of maternal RNA of sea urchin eggs after fertilization.

Between fertilization, or parthenogenetic activation, and the two-cell stage, the content of polyadenylic acid in sea urchin eggs doubles, and the increase occurs primarily in the ribosome-polyribosome fraction. The increase is due to polyadenylation of preexisting RNA molecules synthesized during oogenesis. The polyadenylation occurs in activated, enucleated merogons. It is argued that cytoplasmic polyadenylation may play a role in mobilization of maternal messenger RNA for translation and the polyadenylic acid does not subserve an exclusively nuclear function.

Adenine Nucleotides↗
PubMed1971

The effects of 5-bromodeoxyuridine on yolk sac erythropoiesis in the chick embryo.

The effects of the thymidine analog, 5-bromodeoxyuridine (BUdR), on the formation of red cells in the yolk sac of the chick embryo were examined. The prospective area opaca vasculosa from a definitive primitive streak embryo was excised, disaggregated, and deposited into a cell clump, and the cell clump was placed in organ culture. Hemoglobin synthesis is detectable after about 16 hr in culture. The formation of erythropoietic foci and incorporation of (55)Fe into heme were used to measure the extent of erythropoiesis. Exposure to 40 microg/ml of BUdR within 6 hr after explantation almost completely eliminated red cell formation; subsequent transfer to thymidine medium showed that the inhibition was reversible, and there was no histological evidence of analog toxicity. Between 6 and 12 hr after initiation of organ culture, the tissue became completely refractory to BUdR. DNA synthesis, as monitored by thymidine-(3)H and BUdR-(3)H pulses, was extensive both during and after the period of BUdR sensitivity. Hence, during both BUdR sensitive and insensitive periods the analog was incorporated into DNA of cells which had not yet synthesized hemoglobin. It is proposed that between 6 and 12 hr a crucial regulatory event for terminal differentiation is perturbed by the presence of BUdR in the chromosomes.

Animals↗
PubMed1969

Properties of nuclear RNA in sea urchin embryos.

Pulse-labeled RNA in early sea urchin embryos (64 cells to mesenchyme blastulase) is found almost exclusively associated with the nucleus and turns over very rapidly. The rate of labeling of the cytoplasm is much slower and is consistent with the transfer of 6 per cent of the nuclear RNA made every 15-20 minutes. Most of the pulse-labeled nuclear RNA exists in membrane-bound polyribosomes.

Animals↗