Prostaglandin release by zygotes and endometria of pregnant rabbits

When 4-day rabbit zygotes were incubated for 1 h at 37 degrees C in vitro, very little prostaglandin (PG) was released into the medium, and the concentration of PGs in the zygotes after incubation was also low. The release of prostaglandin E (PGE) and prostaglandin F (PGF) into the medium, and their concentration in the zygotes after incubation, increased sharply on Days 6 and 7 of pregnancy, reaching, by Day 7, values close to 200 ng of each PG released in 1 h per mg of protein. By contrast, endometrial samples on Days 4 and 5 of pregnancy released more PGF and less PGE than the zygotes of the same ages on a per mg of protein basis, and on Days 6 and 7, less of both PGs. Furthermore, endometrial concentrations of PGs after incubation, except for PGF on Day 4, were always lower than values for zygotes. Endometrial concentrations of PGs on Day 6 were lower before than after incubation. Although there was a slight upward trend in PG release by endometrial samples with increasing length of pregnancy, the changes were minimal and, in the case of PGE, none of the mean values exceeded 1 ng per mg of protein. In 7-day blastocysts, high levels of both PGF and PGE were found in the blastocoelic fluid, and these did not change during the 1-h incubation. The release of PGF and PGE during in vitro incubation of ruptured and washed Day 6 blastocysts was stimulated by arachidonic acid, and that of PGF, but not PGE, inhibited by indomethacin. The release of PGE, but not of PGF, from Day 6 blastocysts was inhibited by low temperature, and the same conditions inhibited release of both PGF and PGE from endometrial cell suspensions. It seems that both blastocysts and endometria have capability to synthesize PGs, the blastocysts being particularly active in this regard on Days 6 and 7 of pregnancy. It is hypothesized that, in vivo, Day 6 and 7 blastocysts release large quantities of PGs which trigger some of the local endometrial changes associated with pregnancy.     

Linkage of the evolutionarily-related serum albumin and alpha-fetoprotein genes within q11-22 of human chromosome 4

Albumin and alpha-fetoprotein are structurally related serum proteins, having a similar gene structure and, conceivably, a common evolutionary origin. To test their relative arrangement in the human genome, the serum albumin and alpha-fetoprotein genes were mapped by in situ hybridization of cloned human albumin or alpha-fetoprotein cDNA to human mitotic chromosome preparations. Analysis of cells hybridized with the serum albumin probe showed that 39% of cells exhibited grains on the proximal portion of the long arm of chromosome 4 (bands q11-22), with these grains comprising 30% of all labeled sites throughout these mitoses. Similarly, in cells hybridized with the alpha-fetoprotein probe, 39% of cells were observed to contain silver grains on 4q11-22, these grains constituting 20% of all labeled sites in these cells. These results demonstrate chromosomal localization and linkage of the serum albumin and alpha-fetoprotein genes within bands q11-22 of the long arm of human chromosome 4.     

Chromosomal mapping of Xenopus 5S genes: somatic-type versus oocyte-type.

Xenopus 5S RNA genes exhibit a pattern of differential expression during development in which some members (oocyte-type) are transcribed only in oocytes, while others (somatic-type) are expressed in both oocytes and somatic cells. Using cloned DNA probes specific for each gene type, we determined the positions of these genes on Xenopus metaphase chromosomes by in situ hybridization. Somatic-type 5S genes in both X. laevis and X. borealis are located at the distal end of the long arm of only one chromosome (number 9). The oocyte-type 5S RNA genes are found at the distal ends of the long arms of most Xenopus chromosomes, including chromosome 9. Thus, large scale differences in chromosomal location cannot explain the selective expression of these genes, as suggested previously.     

Biophysical and Biochemical Studies on Rhinovirus and Poliovirus II. Chemical and Hydrodynamic Analysis of the Rhinovirion

Chemical analysis of rhinovirus 14 revealed a ribonucleic acid (RNA) content of 29.8% and a high adenylic acid content (35%). A partial specific volume of 0.682 cm³/g was obtained for the rhinovirion. Rhinovirus and poliovirus had identical sedimentation coefficients of 158S. A diffusion coefficient of 1.71 × 10⁻⁷ cm²/sec was consistent with a hydrated diameter of 25 nm for the rhinovirion. The calculated molecular weights of the rhinovirion and its genome were 7.1 × 10⁶ and 2.1 × 10⁶ daltons, respectively. Sedimentation analysis of infectious RNA confirmed the similarity of the molecular size of the poliovirus and rhinovirus genomes.     

Alkaline phosphatase of Drosophila melanogaster. II. Biochemical comparison among four allelic forms

Biochemical analyses of partially purified preparations of APH-4 and -6 (common allelic forms) and APH-2 and -10 (rare allelic forms) of D. melanogaster reveal that the two common forms are similar in all properties investigated except for pH optimum (8.0 vs. 8.5). The common and rare forms share certain properties in common but differ in that the common forms are more stable to heat and more sensitive to inhibition by inorganic phosphate. With respect to such properties as substrate preferences and K _i values for inorganic phosphate, the common forms and APH-2 are similar to one another, whereas APH-10 is distinctly different. All four activities show preference for a phosphoaromatic compound as substrate, with O-phosphotyrosine being the best substrate of biological origin. Transphosphorylation, as related to these allelic forms of APH, is discussed.Paper No. 3892 of the Journal Series of the North Carolina State University Agricultural Experiment Station, Raleigh, North Carolina. This study was supported by Atomic Energy Commission Contract AT-(40-1-)-3980.     

A new DNA marker (D4S90) is located terminally on the short arm of chromosome 4, close to the Huntington disease gene

Genetic linkage studies have mapped Huntington's disease (HD) to the distal portion of the short arm of chromosome 4 (4p16.3), 4 cM distal to D4S10 (G8). To date, no definite flanking marker has been identified. A new DNA marker, D4S90 (D5), which maps to the distal region of 4p16.3, is described. The marker was used in a genetic linkage study in the CEPH reference families with seven other markers at 4p16. The study, together with knowledge of the physical map of the region, places D4S90 as the most distal marker, 6 cM from D4S10. A provisional linkage study with HD gave a maximum lod score of 2.14 at a θ of 0.00 and no evidence of linkage disequilibrium. As D4S90 appears to be located terminally, it should play an important role in the accurate mapping and cloning of the HD gene.     

A recombination event that redefines the Huntington disease region

We report both a recombination event that places the Huntington disease gene proximal to the marker D4S98 and an extended linkage-disequilibrium study that uses this marker and confirms the existence of disequilibrium between it and the HD locus. We also report the cloning of other sequences in the region around D4S98, including a new polymorphic marker R10 and conserved sequences that identify a gene in the region of interest.