Genetic Erosion from Modern Varieties into Traditional Upland Rice Cultivars (Oryza sativa L.) in Northern Thailand

The purpose of this study was to assess the extent of genetic erosion of traditional upland germplasm in northern Thailand as a result of gene-flow from distinct strains carrying different genotypes. Even modern variety specific markers have not been developed, there is a comparative population in Laos. Thus, both populations were compared with various characters to evaluate gene-flow from modern variety to landraces. Glutinous and glabrous strains are predominated in Laos. However, such strains were drastically decreased in north–east Thailand. Gene diversity is higher in Thailand, compared to Laos at seven isozyme loci. This was a result of the higher frequencies of Indica strains and heterozygotes in Thailand. Plastid type was also determined by using an INDEL marker. Nearly half of Indica strains carried the Japonica plastid. Heterozygotes also tended to carry Japonica cytoplasm. Such nuclear–cytoplasm substituted strains and heterozygotes were probably generated by natural hybridization. Japonica strains tended to be a maternal donor rather than Indica ones. Or Indica strains would easily release pollens, which grow outside of upland fields.     

Nuclear transfer using a bovine mammary epithelial cell line (BMEC)

The developmental potential of nuclei from a bovine mammary epithelial cell line (BMEC) in nuclear transfer was investigated. For nuclear transfer donors, BMEC cells (passage 15) were cultured for 4–5 days after seeding at cell densities of 1.0 × 10⁵ cells/cm² (high‐density group) or 0.8 × 10⁴ cells/cm² (low‐density group). First, the effective electric stimulation for fusion of enucleated oocytes with BMEC cells was examined. Fusion rates reached maximum with two DC pulses of 30 V/150 µm for 20 µs in the high‐density group and with two DC pulses of 25 V/150 µm for 10 µs in the low‐density group. The fusion rate (37.5%) in the high‐density group was significantly (P < 0.005) lower than in the low‐density group (71.4%). Second, the in vitro developmental potential of nuclear transfer embryos derived from BMEC cells was examined. In the high‐density and low‐density groups, 18.8% and 24.1% of fused oocytes, respectively, developed to blastocyst stage. The results of this study indicate that nuclei from BMEC cells support the development of nuclear transfer embryos to the blastocyst stage and that the efficiency of oocyte–cell fusion is affected by the culture conditions of the donor BEMC cells before nuclear transfer.     

Case of calcifying epithelial odontogenic tumour in a dog

A 12-year-old male shih tzu dog was diagnosed as having a calcifying epithelial odontogenic tumour. One and a half years prior to presentation, a mass was noticed on the right mandible by the owners. Radiography revealed irregular, faintly radiopaque material within the tumour. A right hemimandibulectomy was performed, based on the clinical diagnosis of osteosarcoma. Histopathological evaluation of the mandibular mass showed that it was composed of a polyhedral odontogenic epithelial cell nest, fibrous stroma, homogeneous eosinophilic material and rounded calcifying material. The eosinophilic material was visualised by staining with Congo red, and observed under green birefringence by polarisation microscopy. Although the tumour had not recurred 12 months after surgery, the dog was euthanased because of aspiratic pharyngitis. The literature on the clinical behaviour of calcifying epithelial odontogenic tumours in dogs and cats is reviewed.     

The Possibility of Chromosome Classification as Identified by Trypsin-Giemsa Banding Patterns

Inhalt Möglichkeit einer Chromosomenklassifikation durch eine Trypsin-Giemsa-Bänderungstechnik. Es wird eine modifizierte Trypsin-Giemsa-Bandtechnik für Chromosomen beschrieben, die beim Schwein eine deutliche Bänderung zur Chromosomenidentifikation ergibt. Die Bänderung wird erzielt durch eine Verkärzung der Kolchizineinwirkung auf 30 Minuten und eine Behandlung der 3–5 Tage alten Objektträger mit einer 0,1 % Trypsinlösung (Sörensenpuffer pH 6,8) über eine Dauer von 10–20 Minuten bei 4°C und anschlieβender Färbung mit 2 % Giemsalösung (Phosphatpuffer pH 6,8) für 7–10 Minuten. Mit dieser Technik konnten die 18 autosomalen Chromosomen und die beiden Geschlechtschromosomen des Schweines identifiziert werden. Einzelheiten der G-Bandzeichnung eines jeden Chromosoms dieser Spezies werden beschrieben und in einem Karyotypogramm photographisch und schematisch belegt. Das beschriebene Verfahren kann für Zytogenetiker der Human- und Tiermedizin von Bedeutung sein. Contents In the present paper the authors present a modified trypsin-giemsa chromosomal banding technique showing clear banding patterns for the identification of pig chromosomes. The banding patterns were induced by the reduction of colchicine density or trypsin treatment at a critical temperature of 4°C. Identification of 18 pairs of autosomes and a pair of sex-chromosomes of pig were made successfully. Details of the G-banding patterns of each chromosome were described and illustrated both in a karyotypical photograph and in a schematic diagram. The methods may be of importance to veterinary cytogenetics and genetical pathology, as well as to human medicine.     

Attempt at in vitro maturation of minke whale (Balaenoptera Bonaerensis) oocytes using a portable CO2 incubator

The present study was conducted to investigate whether a portable CO2 incubator was effective for in vitro maturation (IVM) of bovine, porcine and minke whale oocytes, and the effect of maturation media supplemented with different hormones; porcine follicle stimulating hormone (pFSH), estradiol-17beta (E2), or pregnant mare's serum gonadotropin (PMSG): human chorionic gonadotropin (hCG) for minke whale immature oocytes was also examined. In vitro maturation rates of bovine and porcine oocytes cultured in the portable CO2 incubator were not significantly different from the standard CO2 incubator. In minke whale IVM culture using the portable incubator, the maximum expansion of cumulus mass was observed by pFSH/E2 and PMSG/hCG at the end of IVM culture. Moreover, the IVM culture period was shortened to 28-30 h from 96-120 h previously reported. The proportion of matured oocytes cultured in the medium supplemented with pFSH/E2 (26.7%) was significantly higher (P<0.05) than that with PMSG/hCG (6.9%). The present study indicates that a portable CO2 incubator is a useful device for minke whale IVM culture on a research base ship, and the addition of pFSH/E2 into an IVM medium enhanced cumulus expansion and the proportion of minke whale matured oocytes.