Histopathological findings of cleft palate in rat embryos induced by triamcinolone acetonide

Triamcinolone acetonide (TAC), a synthetic glucocorticoid, induces cleft palate resulting from poor development of palatal shelves in mice. However, TAC has no effect on medial edge epithelial cells (MEE cells) in secondary palatal shelves. In the present study, we examined the relationship between the pathogenesis of cleft palate and the effects on MEE cells and palatal mesenchymal cells in rat embryos/fetuses exposed to TAC. Pregnant Wistar Hannover rats were given TAC intramuscularly at 0.5 mg/kg at gestation days (Day) 12, 13, and 14, then embryos/fetuses were harvested on Days 14.5, 15, 16 and 20. The effects of TAC were as follows; an inhibition of palatal mesenchymal cell proliferation on Day 14.5, a decrease in the density of palatal mesenchymal cells and MEE cells, and expression of epidermal growth factor (EGF) receptors in MEE cells on Day 15, and stratified squamous differentiation of MEE cells with expression of cytokeratin and EGF receptors on Day 16. These findings indicated that TAC inhibited the proliferation of mesenchymal cells and affected the differentiation of MEE cells into stratified squamous epithelia in the palatal shelves of rat embryos. However, these stratified squamous MEE cells partially fused with each other. Thus, we suspected that a major contributing factor to the formation of TAC-induced cleft palate might not be the altered differentiation of MEE cells, but the inhibition of mesenchymal cell proliferation.     

Changes in peripheral lymphocyte subsets in the type 1 diabetic dogs treated with insulin injections

Plasma metabolites and peripheral lymphocyte subsets were measured in ten diabetic and ten control dogs to investigate their significances as indicators to evaluate immune states in the diabetic dogs. Diabetic dogs were treated with insulin injections, however their plasma glucose and fructosamine concentrations were significantly higher than those of the controls. There were no significant differences in counts of total white blood cells (WBC) and lymphocyte CD8(+) cells (cytotoxic T cells) between the control and the diabetic dogs. In the diabetic dogs, the counts of CD3(+) (T cells), CD4(+) (Helper T cells) and CD21(+) (B cells) cells and the peripheral lymphocytes CD4/CD8 ratio were significantly lower than those in the control dogs. We confirmed abnormality of lymphocyte subsets in insulin treated diabetic dogs and it may relate to depression of immunocompetence and high susceptibility to common infectious diseases.     

Effect of 6-mercaptopurine on rat placenta

In order to investigate the toxic effects of 6-mercaptopurine (6-MP) on placental development, we examined sequential morphology in the placentas from rats exposed to 6-MP. 6-MP was intraperitoneally administered at 60 mg/kg during gestation days (GDs) 11 to 12, and the placentas were sampled on GD 13, 15 or 21. In the 6-MP-treated group, maternal body weight suppression, increased death embryo/fetus ratio and some malformations were observed. The placenta weights were decreased on GDs 15 and 21. Macroscopically, placentas on GD 21 were small, brittle and thin with a white peripheral rim. Histopathologically, in the labyrinth zone, 6-MP treatment mainly evoked decreased mitosis on GDs 13 and 15, increased apoptotic cell on GDs 13, 15 and 21 and thinning on GDs 15 and 21. In the basal zone, 6-MP evoked decreased mitosis on GDs 13, and PAS-positive material in the spongiotrophoblasts was still detected on GD 15. Thickening of the basal zone was observed with cytolysis of glycogen cells, apoptosis and an increased number of composed cells on GD 21. In conclusion, 6-MP administration in pregnant rats induced growth arrest of the labyrinth zone and developmental delay in the basal zone, leading to small placentas. The fetotoxicity of 6-MP may be responsible for its direct anti-proliferative effects and resulting placental dysfunction.     

Improved embryo development in Japanese black cattle by in vitro fertilization using ovum pick-up plus intracytoplasmic sperm injection with dithiothreitol

The purpose of this study was to determine whether dithiothreitol (DTT) treatment of sperm and ethanol activation improve embryo production by intracytoplasmic sperm injection (ICSI). Further, we compared ICSI with standard in vitro fertilization (IVF) in oocytes obtained from cattle. We demonstrated that DTT reduced the disulfide bond in the bovine sperm head. Using oocytes obtained from a slaughterhouse, ICSI-DTT treatment without ethanol showed the highest rate of blastocyst formation. We applied these results to fertilization using ovum pick-up (OPU). Eleven Japanese black cattle served as donors for OPU plus standard IVF (OPU-IVF). Of them, four donors with low embryo development rates were selected to determine whether embryo development was enhanced by OPU plus ICSI (OPU-ICSI). We assessed effects on embryo development following IVF and ICSI in oocytes obtained using OPU. Blastocyst rates were significantly higher for OPU-ICSI than for OPU-IVF. Our results suggest that OPU-ICSI improves the blastocyst development rate in donors with low embryo production compared with the standard OPU-IVF.     

Influence of Rice Proteins on Eating Quality of Cooked Rice and on Aroma and Flavor of Sake

An improved method for the extraction of storage proteins from rice endosperm under conditions safe for producing food was developed. The contribution of the protein extracts to the eating quality of cooked rice and to the aroma and flavor of sake was examined. Sensory analysis was performed to evaluate the eating quality of cooked rice enriched with the protein extracts. Prolamin‐enrichment increased the hardness of cooked rice, and glutelin‐enrichment degraded the appearance of cooked rice. Physical analyses confirmed that prolamin‐enrichment changed, whereas the glutelin‐enrichment did not change the physical properties of cooked rice. Light and scanning electron microscopy of rice protein extracts revealed small particles of the prolamin extract and larger aggregated particles of the glutelin extract; these features remained after heating. The aroma and flavor of sake were negatively affected by the addition of the protein extracts. Especially, addition of prolamin significantly lowered the evaluation score of the aroma obtained by sensory analysis.     

Construction of a high-density reference linkage map of tea (Camellia sinensis)

A few linkage maps of tea have been constructed using pseudo-testcross theory based on dominant marker systems. However, dominant markers are not suitable as landmark markers across a wide range of materials. Therefore, we developed co-dominant SSR markers from genomic DNA and ESTs and constructed a reference map using these co-dominant markers as landmarks. A population of 54 F₁ clones derived from reciprocal crosses between ‘Sayamakaori’ and ‘Kana-Ck17’ was used for the linkage analysis. Maps of both parents were constructed from the F₁ population that was taken for BC₁ population. The order of most of the dominant markers in the parental maps was consistent. We constructed a core map by merging the linkage data for markers that detected polymorphisms in both parents. The core map contains 15 linkage groups, which corresponds to the basic chromosome number of tea. The total length of the core map is 1218 cM. Here, we present the reference map as a central core map sandwiched between the parental maps for each linkage group; the combined maps contain 441 SSRs, 7 CAPS, 2 STS and 674 RAPDs. This newly constructed linkage map can be used as a basic reference linkage map of tea.     

Variation of the vascular bundle system in Asian wild rice, Oryza rufipogon and its relationship to rachis branch number and growth habit

Accessions of Asian wild rice, Oryza rufipogonGriff., vary in phenology, growth habit, reproductivesystem, panicle architecture and rachis branchnumbers, and in habitat preferences. In this paper 86accessions of annual, perennial and intermediategrowth habit variants have been examined for variationin the numbers of rachis branches in the panicle andvascular bundles in their subtending peduncles.Accessions of annual habit, which regenerate from seedand are adapted to shallow and temporary swamps,developed fewer rachis branches (mean = 6.0) thanthose of perennial habit (mean = 7.2) which largelyregenerate vegetatively and are adapted to stable deepwater habits. In both cases variation within growthhabit groupings was narrow. Variation in vascularbundle numbers, which has not been previouslyreported, was similar (10.1 to 10.3), but morevariable within annuals. As a result the V/R ratio (ofvascular bundles: rachis branches) was higher inannuals (mean = 1.71) than among perennials (mean =1.46). Accessions of annual habit, and adaptedto a wide range of habitats, varied considerably inboth rachis branch (mean = 9.5) and vascular bundlenumbers (mean = 14.0), with V/R ratios similar tothose of perennial growth habit (mean = 1.49).Corresponding measures for both indica and japonica of cultivated rice (O. sativa) variednarrowly and were substantially greater for bothrachis branches (mean = 11.6 and 13.8, respectively)and vascular bundles (mean = 19.1 and 14.8,respectively), with V/R ratios of 1.67 for indica and similar to accessions of O.rufipogon of annual habit, and 1.07 for japonica and lower than accessions of O.rufipogon of both perennial and intermediate habit.Accessions of O. rufipogon from the India andIndochina regions were significantly lower in rachisbranch, but not vascular bundle numbers thanaccessions from China; with the V/R ratio higher amongaccessions from India than found in other geographicregions of origin. The possible role of O.rufipogon accessions of intermediate growth habit inthe evolution of cultivated rice is discussed,although it is speculated that accessions ofintermediate habit with high numbers of rachisbranches and vascular bundles may have resulted frominterspecific hybridization with O. sativacultivars.     

Variations of the vascular bundle system in Asian rice cultivars

Summary The capacity of vascular bundle system transporting assimilates from source to sink is one of the limiting factors for rice (Oryza sativa L.) yield. Genetic variation in vascular bundle system should be investigated for improvement of transporting efficiency. A total of 531 Asian rice cultivars were studied for vascular bundles in the peduncle and its relation to spike morphology. A few difference was detected for the number of primary rachis branches of the spike among the cultivars from various countries. However, the number of vascular bundles significantly differed among the cultivars; those from Nepal, Bangladesh and India bore more vascular bundles than those from Japan. Therefore, the ratio of vascular bundles to rachis branches (V/R ratio) was nearly 1.0 in cultivars from Japan, while those from Nepal, Bangladesh and India ranged from 1.3 to 2.2. Chinese and Indonesian cultivars incuded two types of high and low V/R ratios. Cultivars with high V/R ratio showed positive reactions to the phenol solution, while those with low V/R ratio were negative reactions, suggesting that the former cultivars are of Indica type and the latter of Japonica type. It was concluded that the relationship between vascular bundles and rachis branches differentiated among the ecotypes of Asian cultivated rice.     

Methane Production after Liming to Tropical Acid Peat Soil

Tropical acid peat land could be an emission source of greenhouse gases, especially, of methane, because peat soil contains large amount of carbon. When these acid peat lands are utilized for farming, adjustment of the acid condition by adding lime (CaCO₃) becomes essential. However, by adding lime to these soils, methane and carbon dioxide production potentials were increased in various acid peat soils. Soluble organic carbon also increased in soils by the lime addition. It was due to that the soil pH rose by liming and the decomposition of organic matter was enhanced under these conditions.