Characterization of vitamin B<Subscript>12</Subscript> compounds from marine foods

Vitamin B₁₂ is synthesized by only certain bacteria and archaea but not by animals or plants. In marine environments, bacterial vitamin B₁₂ is transferred and concentrated into fish and shellfish bodies by plankton in the marine food chain. Moreover, marine macrophytic red algae, Porphyra spp. specifically contain substantial amounts of vitamin B₁₂, due to microbial interaction. Although some meats or viscera of edible fish and shellfish are excellent sources of biologically active vitamin B₁₂, an inactive corrinoid, pseudovitamin B₁₂, was found in some edible shellfish using liquid chromatography/electrospray ionization–tandem mass spectrometry. To prevent elderly people from developing vitamin B₁₂ deficiency due to food protein-bound vitamin B₁₂ malabsorption, we present a survey of marine foods containing free vitamin B₁₂. The results of our study suggest that bonito and clam extracts (or soup stocks), which contain considerable amounts of free vitamin B₁₂ are useful not only as seasonings and flavorings but also as excellent sources of free vitamin B₁₂.     

Low mitochondrial DNA diversity of Japanese Polled and Kuchinoshima feral cattle

This study aims to estimate the mitochondrial genetic diversity and structure of Japanese Polled and Kuchinoshima feral cattle, which are maintained in small populations. We determined the mitochondrial DMA (mtDNA) displacement loop (D‐loop) sequences for both cattle populations and analyzed these in conjunction with previously published data from Northeast Asian cattle populations. Our findings showed that Japanese native cattle have a predominant, Asian‐specific mtDNA haplogroup T4 with high frequencies (0.43–0.81). This excluded Kuchinoshima cattle (32 animals), which had only one mtDNA haplotype belonging to the haplogroup T3. Japanese Polled showed relatively lower mtDNA diversity in the average sequence divergence (0.0020) than other Wagyu breeds (0.0036–0.0047). Japanese Polled have been maintained in a limited area of Yamaguchi, and the population size is now less than 200. Therefore, low mtDNA diversity in the Japanese Polled could be explained by the decreasing population size in the last three decades. We found low mtDNA diversity in both Japanese Polled and Kuchinoshima cattle. The genetic information obtained in this study will be useful for maintaining these populations and for understanding the origin of Japanese native cattle.     

Regeneration of protoplasts from hyphal strands ofVolvariella volvacea

A series of experiments on the preparation and regeneration of protoplasts from hyphal strands ofVolvariella volvacea (Bull. ex. Fr.) Singer were conducted with the aim of optimizing the conditions for its efficient regeneration. One commercial (Vvcl) and two wild (EAAC-0001 and EAAC-0002) strains ofV. volvacea from the Philippines were used and subjected to varying conditions to determine the most efficient means for regeneration of their protoplasts. The effects of age and type of strain, pH, type and concentration of osmotic stabilizer, enzymatic composition, treatment time, temperature, reciprocal frequency during enzymatic lysis of the cell wall, and centrifugation conditions were investigated. Results showed that the three strains ofV. volvacea had varying responses in terms of yield, size, and ability of their protoplasts to regenerate into the protoplast regeneration medium. Among the three strains, EAAC-0002 had the highest rate of regeneration. The 5-day-old culture ofV. volvacea, when subjected to a combination of 2% Novozyme 234 and 0.2% chitinase in 0.6M mannitol (pH 6.0) for 3 h at 30°C, 90 strokes/min and centrifuged at 1100 g for 10 min; produced an efficient yield of protoplasts with a relatively high regeneration rate.Part of this paper was presented at the 47th annual meeting of the Japan Wood Research Society, Kochi, Japan, April 2–5, 1997     

Identification and validation of quantitative trait loci associated with seed yield in soybean

In soybean [Glycine max (L.) Merrill], the genetic analysis of seed yield is important to aid in the breeding of high-yielding cultivars. Seed yield is a complex trait, and the number of quantitative trait loci (QTL) involved in seed yield is high. The aims of this study were to identify QTL associated with seed yield and validate their effects on seed yield using near-isogenic lines. The QTL analysis was conducted using a recombinant inbred line population derived from a cross between Japanese cultivars ‘Toyoharuka’ and ‘Toyomusume’, and eight seed yield-associated QTL were identified. There were significant positive correlations between seed yield and the number of favorable alleles at QTL associated with seed yield in the recombinant inbred lines for three years. The effects of qSY8-1, a QTL promoting greater seed yield, was validated in the Toyoharuka background. In a two-year yield trial, the 100-seed weight and seed yield of Toyoharuka-NIL, the near-isogenic line having the Toyomusume allele at qSY8-1, were significantly greater than those of Toyoharuka (106% and 107%, respectively) without any change for days to flowering and maturity. Our results suggest that qSY8-1 was not associated with maturity genes, and contributed to the 100-seed weight.     

Overcoming hybrid lethality in a cross between Japanese pear and apple using gamma irradiation and confirmation of hybrid status using flow cytometry and SSR markers

Although there have been some attempts to obtain intergeneric hybrids between Japanese pear (Pyrus pyrifolia Nakai) and apple (Malus × domestica Borkh.) mature hybrids have not been generated due to hybrid lethality. Shoots from immature hybrid embryos were gamma irradiated and cultured at normal temperature conditions to obtain viable intergeneric plants. Gamma irradiation doses of 50 and 100 Gy cultured at 25 °C killed all shoots but there was one survivor at 150 Gy and 25 °C. Hybrid status of the shoot was confirmed by using morphology, flow cytometry and SSR markers. The intergeneric plant had similar leaf serrations to apple and similar petioles to Japanese pear. Flow cytometric analysis revealed that the intergeneric shoot had a DNA content intermediate between the parents. SSR analysis showed one allele from each parent for all 16 SSR loci investigated. These data strongly suggest that the obtained shoot is a true hybrid between Japanese pear and apple.     

Toe white line separation associated with the notch (crena marginalis) on the distal phalanges in Thoroughbred yearling horses

The shape of the white line of the hoof is closely related to the shape of the notch on the dorsal distal bearing border of the distal phalanx (P3). In this study, a radiographic survey of the P3 of both forelimbs of 163 Thoroughbred yearling horses was conducted. The correlation of the depth and width of the notch were analyzed with the toe white line separation grades (0 to 3). As a result, the toe white line separation grade increased, the depth and the width of the notch also increased significantly. Radiographic examination of the P3 of the forelimbs might be useful for deciding whether to implement hoof care to prevent onset of toe white line separation.     

Equine nonneoplastic abnormal ovary in a draft mare with high serum anti-Müllerian hormone: a case study

We performed a standing hand-assisted laparoscopic ovariectomy in a draft mare that presented with high serum anti-Müllerian hormone (AMH) level and had an enlarged single cystic ovary. Histopathological examination revealed no tumor cell proliferation in the ovary, but the presence of a large ovarian cyst was confirmed. In the diagnosis of abnormal ovaries in mares, a comprehensive assessment should be performed, including the monitoring of ovarian morphology and biomarkers over time, to determine the disease prognosis and treatment plan. The case of this mare with a nonneoplastic abnormal ovary and increased serum AMH level was rare. We suggest that standing hand-assisted laparoscopic ovariectomy is useful for the removal of large ovaries in draft mares.