Induction of short-term pseudopregnancy in gilts by the administration of estradiol benzoate or estradiol dipropionate to achieve ovulatory synchronization for embryo collection

A study was conducted to investigate whether ovulation in gilts could be synchronized for embryo collection by the administration of estradiol benzoate (EB) or estradiol dipropionate (EDP) to induce pseudopregnancy, followed by the treatment with prostaglandin F_2α (PGF_2α) on 10 days after. Ten gilts each received a total of 20 mg of EB or EDP on Day 10 or EB on Day 10 and 14 to induce pseudopregnancy (Day 0 = onset of estrus). Donors received PGF_2α 10 or 15 days (as a control) after the first administration of estrogens and subsequently eCG and hCG, and were then inseminated artificially. The embryos were collected 7 days after the administration of hCG, and assessed for embryo yield and their developmental stages. All protocols resulted in good embryo yield (9.8–13.2 embryos in average), and the embryos showed average ability to develop to the expanded blastocyst stage (3.29–4.03 as developmental scores) without any significant differences among the protocols. These results suggest that the administration of PGF_2α 10 days after the treatment of gilts with EB or EDP would allow synchronization of ovulation and embryo collection, as well as shortening the period from estrus detection to embryo collection, thus improving embryo collection efficiency.     

Prepartum maternal plasma glucose concentrations and placental glucose transporter mRNA expression in cows carrying somatic cell clone fetuses

In this study, the plasma glucose concentrations of cows carrying a somatic cell clone fetus during late pregnancy and placental glucose transporter (GLUT) mRNA levels at parturition were examined. Parturition was induced using dexamethasone, prostaglandin F(2α) and estriol in cows bearing a clone (Clone) or a fetus fertilized in vivo as a control (DEX). Plasma glucose concentrations were measured in the cows (days 257 and 271 of pregnancy and at parturition) and newborn calves. Cotyledon and caruncle tissues removed just after parturition were used for mRNA extraction. Expression of mRNA was also analyzed in control cows that were induced to undergo parturition without dexamethasone (PG) or that spontaneously delivered (SP). The glucose concentrations of the Clone group were significantly low at all points examined, but those of the calves were normal. The increase in the maternal glucose concentration from day 257 to parturition was significantly lower in the Clone group. Glucose concentrations were negatively correlated with birth weight for clones (day 257; r=-0.584, day 271; r=-0.286, parturition; r=-0.549). There was no difference in mRNA levels in the cotyledons among the animals examined. In the caruncles, the Clone and PG groups showed significantly higher GLUT1 and GLUT3 mRNA levels than the SP group, and the GLUT3 mRNA level was significantly higher in the Clone group than in the DEX group. The glucocorticoid receptor α mRNA level was significantly lower in the SP group than in the DEX group. Although spontaneous parturition and administration of dexamethasone suppressed the placental GLUT mRNA levels, the action was not observed in clone pregnancy. These results raise the possibility of facilitation of glucose transportation through the placenta to meet increased nutritional requirements of overgrown clone fetuses.     

Fundamental studies on the physiology of rotifers in mass culture—V. Dry Chlorella powder as a food for rotifers

The dietary value of dried, commercial Chlorella was compared with that of living marine Chlorella, and yeast, in relation to growth of the rotifer Brachionus plicatilis raised individually and by batch culture methods.A concentration of 50 μg/ml of dried Chlorella powder is near an optimal density for rotifer growth. The dried material in suspension is less effective for growth than living marine Chlorella, although it is much more effective than a suspension of yeast at the same density (50 μg/ml).In batch culture (12-l glass vessel), the rotifers grew from an initial inoculation of 13.2 individuals/ml to a density of 434 individuals/ml by the 16th day. About 10⁷ rotifers could be removed from one batch culture in five harvests in the 41-day experimental period.The results indicate that dried Chlorella powder is an effective food for the rotifer Brachionus plicatilis.     

Effects of the estrous cycle on the efficacy of oocyte collection and in vitro embryo production in Duroc‐breed

Collection efficacy and in vitro embryo developmental ability of oocytes obtained from Duroc‐breed ovary donors at different stages of the estrous cycle (days 6, 12 and 16 after estrus) were performed. The numbers of collected oocytes did not differ significantly among the different estrous cycle groups (total 72–90 oocytes per gilt). However, the blastocyst rates of oocytes collected on days 12 and 16 (9.2% and 19.4%, respectively) were significantly higher than those on day 6 (1.1%). More oocytes were obtained on day 16 from small follicles (<2 mm in diameter; 85.3 oocytes per gilt) than from medium‐sized (≥2–<6 mm) and large (≥6 mm) follicles (17.5 and 12.8 oocytes, respectively). The blastocyst rates in both the medium‐sized and large follicle groups (20.0% and 19.2%, respectively) were significantly higher than that in the small follicle group (6.3%). The blastocyst cell numbers in both the medium‐sized and large follicle groups (39.4 and 43.3 cells, respectively) were significantly higher than that in the small follicle group (30.6 cells). The results suggest that oocyte collection from cycling Duroc pigs can be carried out efficiently from the late luteal to follicular stage. Those oocytes collected from medium‐sized and large follicles show better embryo development.     

Decreasing radioactive cesium in lodged buckwheat grain after harvest

This study assessed soil contamination with high radioactive cesium (R–Cs) concentration in buckwheat grains by lodging, and assessed the possibility of R–Cs reduction in grain through post-harvest preparation. Analysis of buckwheat grain produced in farmers’ fields and reports from farmers indicated that grain from fields that had lodging showed higher R–Cs than grain from fields with no lodging. A field experiment demonstrated that R–Cs in grain after threshing and winnowing (TW) was about six times higher in lodged plants than in nonlodged plants. In lodged plants, R–Cs in grain was decreased to about one-fourth by polishing, and was decreased to about one-seventh by ultrasonic cleaning, compared with R–Cs in grain after TW. These results demonstrate that R–Cs of buckwheat grain of lodged plants can be decreased by removing soil from the grain surface by polishing and winnowing.     

Epitopes and nuclear localization analyses of canine distemper virus nucleocapsid protein by expression of its deletion mutants.

A series of nucleocapsid protein (NP)-deleted genes of the Onderstepoort strain was constructed in order to locate antigenic regions of the NP of canine distemper virus. The expression of proteins from 5'-deleted NP genes was examined in COS-7 cells by indirect immunofluorescence assay using three monoclonal antibodies (MAbs), c-5, f-5 and h-6, and a rabbit serum against NP. These MAbs reacted with two regions of NP. Amino acid residues from 1 to 80, and 337-358, were necessary and sufficient for formation of the epitopes identified by MAbs f-5 and h-6, and c-5, respectively. The proteins translated from intact or 3'-deleted genes were found to be localized in the nuclei of COS-7 cells, whereas the proteins from the 5'-deleted genes were mainly detected in the cytoplasm. These results suggested that 80 amino acid residues at the N-terminus are required for transportation of NP into the nucleus.     

Immunohistochemical detection of apolipoprotein A-I and B-100 in canine atherosclerotic lesions

We attempt to determine and compare the localization of apolipoproteins (apo) apoA-I and B-100 in atherosclerotic lesions of canine aortas, coronary arteries, and the peripheral arteries, using immunohistochemical techniques. Histopathologically, atherosclerotic lesions were characterized by deposition of lipids and infiltration of lipid-laden foamy cells in the tunica intima and tunica media, sometimes forming fibrofatty plaques containing abundant sudanophilic and mineralized material. Canine apoA (CapoA)-I and canine apoB (CapoB)-100 immunopositive signals were simultaneously observed in mild and severe atherosclerotic lesions of the aorta, coronary arteries, splenic arteries, and renal arteries in the double-immunolabeled sections. Both CapoA-I and CapoB-100 positive signals were seen in the cytoplasm of endothelial cells, smooth muscle cells, and macrophages. The subendothelial space and extracellular matrix in the tunica intima and media were also positive. Neither CapoA-I nor CapoB-100 positive signals were seen in normal arteries. These findings closely resemble those of the localization of apoA-I and apoB-100 in human atherosclerotic lesions.     

Immunohistochemical detection of the enzyme glutamic acid decarboxylase and hormones of the islets of Langerhans in spontaneous insulin-dependent diabetes mellitus in cattle

Immunohistochemical expression of glutamic acid decarboxylase (GAD) enzyme was detected in the pancreatic islets of 12 cattle with spontaneous insulin-dependent diabetes mellitus (IDDM). The most characteristic changes were atrophy and decreased number of pancreatic islets, enlarged islets with vacuolated beta cells, and lymphocytic islet adenitis. Atrophied islets were composed of small islet cells without cytoplasmic insulin-positive granules. Immunohistochemically, GAD was not found in the cytoplasm of atrophied islet cells. Furthermore, enlarged islets consisting of islet cells with vacuolated cytoplasm were frequently observed. The cytoplasm of vacuolated cells contained very few GAD- and insulin-positive granules, indicating beta cell destruction. Enlarged islets with mild lymphocytic infiltrates were frequently observed. These findings suggest that islet cells in cattle with IDDM lose their insulin synthesis function and their ability to regulate hormonal secretion of alpha and delta cells.     

Seedling demography and establishment of Cryptomeria japonica in a cool-temperate, old-growth, conifer hardwood forest in the snowy region of Japan

To clarify the establishment pattern of Cryptomeria japonica seedlings, the demography of current-year seedlings was studied under various micro-environmental conditions for 2 years in a cool-temperate old-growth forest in the snowy region of Japan. In both years, more than 70% of seedlings that emerged died within a year, and differences in the survival rate of seedlings with respect to micro-environmental conditions were similar. While a number of seedlings survived at the sites on fallen logs and in mineral soil, almost no seedlings survived at the sites with either broad-leaved or coniferous litters at the end of the first growing season. The negative litter effect may kill most small seedlings of C. japonica. In addition, we found that survival rates of the seedlings were greater as the distance from the nearest adult and canopy openness increased. An analysis using Quantification Theory I showed that, of the possible micro-environmental factors, substrate conditions had the strongest effect on the survival of seedlings. The analysis also indicated that distance from the nearest adult and canopy openness also affected seedling survival significantly and to almost the same extent, although the effects were weaker than those for the substrate condition. Given the limited establishment sites for C. japonica seedlings, layering is suggested to be the main mode of regeneration in this forest.