Effect of hCG on the 13,14-dihydro-prostaglandin F2-alpha forming capacity of the ovary after ovulation in PMSG-primed immature female rats

We have examined the change in the ovarian 13,14-dihydro-prostaglandin F2 alpha (13,14H2-PGF2 alpha) forming capacity after the first ovulation induced by injection of pregnant mare serum gonadotropin (PMSG 5 IU, sc) at 26 days of age. After ovulation, the 13,14H2-PGF2 alpha forming capacity in the whole ovary (WO) and in non-luteal ovarian tissues (WO-CL) gradually decreased, whereas a rapid decrease of the synthesizing capacity was observed in corpus luteum (CL). The capacity in WO 4 days after ovulation (33 days of age) was markedly stimulated by human chorionic gonadotropin (hCG 10 IU, ip) administration, whereas CL at 33 days of age did not respond to the stimulatory effect of hCG. A single injection of hCG on day 7 after hypophysectomy resulted 12 hrs later in a significant increase in the forming capacity of 13,14H2-PGF2 alpha in WO-CL. These results indicate that the 13,14H2-PGF2 alpha forming capacity in CL rapidly decreases after the first ovulation and the WO-CL, but not CL, retain the ability to form 13,14H2-PGF2 alpha in response to exogenous gonadotropin for a long time.     

Nucleotide sequence of the coding region of the mouse N-myc gene.

A genomic clone for the mouse N-myc gene was isolated and the total nucleotide sequence (4807 bp) of the two coding exons and an intron located between them was determined. The amino acid sequence of the N-myc protein was deduced from the DNA sequence. This protein is composed of 462 amino acids, slightly larger than human and mouse c-myc proteins, and is rich in proline like the c-myc protein. Comparison of the amino acid sequences of the mouse N-myc and c-myc proteins showed that conserved sequences are located in eight regions: four regions are in the N-terminal half of the N-myc protein and are separated from each other by regions poorly homologous to those of the c-myc protein, and the four others are located in the C-terminal half, throughout which certain homology exists. A remarkable sequence containing 13 successive acidic amino acids is present in one of the conserved regions located in the middle of the N-myc protein.     

Induction of superovulation in prepubertal female rats by anterior pituitary transplants

Transplants of 26-day-old rats of an anterior pituitary gland from adult intact or castrated male, 20-day-old or adult ovariectomized female donors (all of which contained large amounts of FSH) resulted in superovulation in recipients on the morning of Day 29. Transplants of the gland from 20-day-old males and adult cyclic females could not advance the time of first ovulation or induce superovulation. In the rats in which superovulation could be induced, a marked increase in plasma FSH was noted in recipients shortly after transplantation and the high levels of plasma FSH were maintained until at least 12 h after grafting. These rats also showed preovulatory surges of LH and FSH 54 h after grafting. No obvious elevation of plasma FSH was noted over 72 h in recipients in which superovulation could not be induced. These findings suggest that the final maturation of follicles for superovulation is induced by a transient release of a large amount of FSH from the grafted pituitary gland and that the sex of the pituitary donor has no bearing on this phenomenon.     

Correlation between acrasins and spore germination inhibitors in cellular slime molds.

Discadenine,3-(3-amino-3-carboxypropyl)-N6-delta 2-isopentenyladenine, which inhibits spore germination, was previously found in Dictyostelium discoideum. Studies on the distribution of discadenine in different species of cellular slime molds by high-pressure liquid chromatography showed that discadenine is present in D. discoideum, Dictyostelium purpureum, and Dictyostelium mucoroides, but not in Dictyostelium minutum, Polysphondylium violaceum, or Polysphondylium pallidum. Discadenine synthetase, which is involved in biosynthesis of discadenine with N6-delta 2-isopentenyladenine as substrate, was only detected in cells of the former three species. In addition, discadenine inhibited spore germination only in these three species. These results clearly demonstrate that discadenine is produced as an inhibitor of spore germination in the species of cellular slime molds in which the acrasin is cyclic adenosine 5'-monophosphate (AMP). This means that there is a structural and biochemical correlation between the spore germination inhibitor and the acrasin, since 5'-AMP, a direct precursor in discadenine biosynthesis, can be derived from cyclic AMP by hydrolysis with cyclic AMP phosphodiesterase.     

Changes in peripheral levels of bioactive and immunoreactive inhibin, estradiol-17 beta, progesterone, luteinizing hormone, and follicle-stimulating hormone associated with follicular development in cows induced to superovulate with equine chorionic gonadotropin.

Changes in concentrations of bioactive and immunoreactive (ir-) inhibin, estradiol-17 beta, progesterone, LH, and FSH in peripheral blood were determined in cows induced to superovulate with eCG. The pattern of follicular growth was also characterized by daily ultrasonographic examination. Hormonal profiles and follicular development during the intact estrous cycle of the same animals before eCG treatment served as controls. Equine CG increased the number of follicles of various sizes (small, greater than or equal to 4 less than 7, medium, greater than or equal to 7 less than 10; large, greater than or equal to 10 mm in diameter) by 4 days after administration. The second growth of large follicles occurred within 1 day after superovulation. Inhibin bioactivity in jugular vein blood was detectable 48 h after eCG injection (44 h before LH peak), whereas it was not detected before administration of eCG or during control cycles. Circulating levels of bioactive inhibin further increased during the two waves of growth of large follicles. The highest activity of inhibin was noted at the time of the preovulatory LH peak (0 h). Thereafter, bioactivity of inhibin in peripheral plasma dropped from 0 to 24 h after the LH peak, and the activity increased again at 72 h compared to the value at -44 h. Plasma levels of ir-inhibin showed a pattern similar to changes in bioactive inhibin in the eCG-treated cows. Plasma concentrations of estradiol-17 beta also increased concomitantly with two waves of growth of large follicles. There was no correlation between plasma levels of progesterone and inhibin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Specific phosphorylation of the acidic central region of the N-myc protein by casein kinase II.

The central region of the N-myc protein has a characteristic amino acid sequence EDTLSDSDDEDD, which is very similar to those of particular domains of adenovirus E1A, human papilloma virus E7, Simian virus 40 large T, c-myc and L-myc proteins. Domains of these three viral oncoproteins have recently been shown to be specific binding sites for the tumor-suppressor gene retinoblastoma protein. We have noted that the sequence of serine followed by a cluster of acidic amino acids is exactly the same as that of a typical substrate of casein kinase II (CKII). Therefore, we investigated whether these nuclear oncoproteins are phosphorylated by CKII. For this purpose, we fused the beta-galactosidase and N-myc genes including this domain and expressed it in Escherichia coli cells. Several mutant N-myc genes, containing single amino acid substitutions in this domain, were also used to produce fused proteins. Strong phosphorylation by CKII was detected with the fused protein of wild-type N-myc. However, no phosphorylation of beta-galactosidase itself was observed and the phosphorylations of fused mutant proteins were low. Another fused N-myc protein containing most of the C-terminal region downstream of this acidic region was not phosphorylated by CKII. Analysis of phosphorylation sites in synthetic peptides of this acidic region identified the major sites phosphorylated by CKII as Ser261 and Ser263. On two-dimensional tryptic mapping of phosphorylated N-myc proteins, major spots of in vitro-labeled and in-vivo-labeled N-myc proteins were detected in the same positions. These results suggest that two serine residues of the acidic central region of the N-myc protein are phosphorylated by CKII in vivo as well as in vitro. The functional significance of this acidic domain is discussed.     

Immunotherapy of B lymphoma by anti-idiotype antibodies: Characterization of variant tumour cells appearing a long time after the initial tumour inoculation

Summary Immunotherapy of a murine B-cell lymphoma by antibodies to idiotypic determinants of its IgM, resulted in surviving tumour-free mice. Several of these mice, however, did develop tumours a long time after the initial inoculation of the tumour cells, or upon rechallange of the survivors with B-lymphoma cells. The presence of tumour cells during this long latent period may have been due to the development in the host of an anti-idiotype immune response. These late-developing tumours were detected by a radioimmunoassay and characterized by immunofluorescent staining and sodium dodecyl sulphate/polyacrylamide gel electrophoresis. Cells of some late-developing tumours lost the idiotype recognized by the antibodies used for the immunotherapy. Several of these tumours expressed IgM on the cell surface, while others did not, because of the absence of light chains. They were identical in the structure of their rearranged µ chain genes proving their derivation from the original inoculation. Cell lines obtained from the late-developing tumours differed in their tumorigenicity. The appearance of idiotype-negative tumour cells as a result of anti-idiotype immunotherapy has a great impact in our efforts to cure lymphoma by this modality.     

Alternation in colonization behaviors of Escherichia coli cells with rpoS or yggE deficiency on solid surfaces

Colonization on a solid surface is influenced by the cell surface appendages such as flagella and curli, of which expressions are regulated by rpoS gene encoding a sigma factor. In this study, we investigated the effect of rpoS or yggE (a rpoS‐related and stress‐responsive gene) deficiency on the colonization of Escherichia coli BW25113. Under a static condition, the deletion of rpoS or yggE induced 3.9‐ and 3.7‐fold higher colonization as compared to wild‐type cells, respectively, on the solid surfaces. However, under a liquid flow condition, only ΔyggE cells maintained the stable colonization on the surface, and the values of cell layer thickness and cell coverage on the surface were 17 and 9.2 times as high as those of wild‐type cells, respectively. Gene expression analyses revealed that the deletion of rpoS or yggE positively impacted the expressions of genes involved in flagellum formation. On the other hand, curli assembly was severely prohibited by the rpoS deficiency. Here, we proposed that the plentiful flagella on the ΔrpoS and ΔyggE cell surfaces facilitated mainly the colonization under the static condition. Meanwhile, curli existing on the ΔyggE cell surface played an important role in keeping stable cell attachment and developing attached colonies under the flow stress condition. Biotechnol. Bioeng. 2013; 110: 1050–1056. © 2013 Wiley Periodicals, Inc.