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

R. Ishikawa  S. Yamanaka  Y. Fukuta  S. Chitrakon  C. Bounphanousay  K. Kanyavong  L.-H. Tang  I. Nakamura  T. Sato  Y.-I. Sato 《Genetic Resources and Crop Evolution》2006,53(2):245-252

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.  相似文献   

Pathological changes of tracheal mucosa in chickens infected with lentogenic Newcastle disease virus   总被引：1，自引：0，他引：1  

T Kotani  Y Odagiri  J Nakamura  T Horiuchi 《Avian diseases》1987,31(3):491-497

Forty-day-old specific-pathogen-free chickens were exposed by aerosol to lentogenic Newcastle disease virus (NDV) and observed for 24 days for pathological changes in the tracheal mucociliary system. Specific fluorescence of NDV antigen was observed through day 5 postexposure (PE) in the cytoplasm of the tracheal epithelium and desquamated epithelium in the lumen. On day 1 PE, scanning electron microscopy revealed hypertrophy of goblet cells and small patches of the deciliated epithelium scattered mainly around the openings of mucous glands. The deciliated area of tracheal surface increased through day 4 PE. Light microscopy showed small vacuoles containing lymphocytes and heterophils in the epithelial layer. Immature epithelium proliferated in some areas. On days 5 and 6 PE, ciliated areas of the trachea tended to increase as a result of regeneration of the epithelium, still leaving many nonciliated patches of various sizes. On and after day 8 PE, there remained plaques with nonciliated flat epithelium, but most areas were covered with well-ciliated epithelium. Non-ciliated plaques were observed until day 24 PE, but they gradually decreased in size. These plaques were covered by a single layer of flat epithelium and were formed upon lymph follicles in subepithelial tissue.  相似文献   

Escherichia coli multiplication and lesions in the respiratory tract of chickens inoculated with infectious bronchitis virus and/or E. coli.     

K Nakamura  J K Cook  J A Frazier  M Narita 《Avian diseases》1992,36(4):881-890

Escherichia coli numbers and histopathological changes were studied in the respiratory tract of line 151 chickens intranasally inoculated with infectious bronchitis virus (IBV) and/or virulent E. coli; this line is highly susceptible to IBV. Chickens inoculated with IBV alone showed increased numbers of E. coli in the trachea and had tracheitis, airsacculitis, and bronchiolitis. One of 17 chickens inoculated with IBV alone died with fibrinopurulent serositis. Chickens inoculated with IBV and E. coli had more severe and persistent respiratory lesions than those inoculated with IBV alone. E. coli was isolated from tracheas of chickens inoculated with IBV and E. coli more frequently than from chickens inoculated with IBV alone. In this group, 14 of 27 chickens died with tracheal plugs or with fibrinopurulent serositis. There was neither increased numbers of E. coli nor significant lesions in the respiratory tract of the group inoculated with E. coli alone. These results suggest that IBV may facilitate E. coli invasion into the lower respiratory tract of the chicken.  相似文献   

An enzootic of calf pneumonia associated with Mycoplasma bovirhinis     

T Shimizu  D Nosaka  N Nakamura 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1973,35(6):535-537

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Histopathology of spermatocele of fowl (author's transl)]     

M Nakamura  M Inoue 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1979,41(1):41-51

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Effect of parthenocarpy,peeling and fruit age on the changes in volume and specific gravity of cucumber fruits during storage at 20°C     

R. Sakiyama  Yuzo Nakamura  S. Nakamura 《Scientia Horticulturae》1978,8(3):229-236

Either parthenocarpically grown, peeled or at any stage of picking, cucumber fruits showed a tendency to increase in volume and decrease in specific gravity while they were stored under unsaturated vapour pressure at 20°C. The amount of change varied according to the treatment.Recovery from a flaccid appearance occurred in all fruit except very young ones. In those fruits the incipient recovery from wilting, an increase in volume and a decrease in specific gravity, coincided.Parthenocarpic fruits showed an increase in volume at almost the same rate in any transverse quarter of a fruit, in contrast to the pollinated ones in which the most distal quarter enlarged more than the other parts. Pithy appearance of the fruit wall was evenly distributed through a parthenocarpic fruit to a moderate degree, but at the proximal half of a pollinated one it was severe.  相似文献   

Epidemiology, pathology, and immunohistochemistry of layer hens naturally affected with H5N1 highly pathogenic avian influenza in Japan     

Nakatani H  Nakamura K  Yamamoto Y  Yamada M  Yamamoto Y 《Avian diseases》2005,49(3):436-441

Epidemiology, pathology, and immunohistochemistry were investigated in layer hens affected with H5N1 highly pathogenic avian influenza, which occurred for the first time in 79 years in Japan. The farm, which had a total of 34,640 chickens, experienced up to 43.3% mortality before the chickens were depopulated. Clinically, the affected chickens exhibited mortality without apparent clinical signs. Histologically, hepatocytic necrosis; necrosis of ellipsoids and follicles with fibrin in the spleen; necrosis with glial nodules in the brain stem, cerebrum, and cerebellum; necrosis of acinar cells in the pancreas; and necrosis of lymphoid tissues in intestinal lamina propria were seen. Occasionally, mild bronchiolitis, degeneration of smooth muscle fibers in the cecum, and mild tubulonephrosis were noted. Immunohistochemically, influenza virus antigens were detected often in the liver and spleen, heart, intestine, gizzard, proventriculus, and oviduct. In addition, antigens were seen also in the brain, kidney, pancreas, and ovary, but seldom in the lung and trachea. Virus antigen was mainly detected in the capillary endothelium and parenchymal cells. This suggests that virus excretion from the respiratory tract was not as prevalent as that from the digestive tract in the present cases.  相似文献   

Inhibitory effect of several fluoroquinolones on hepatic microsomal cytochrome P-450 1A activities in dogs     

Regmi NL  Abd El-Aty AM  Kuroha M  Nakamura M  Shimoda M 《Journal of veterinary pharmacology and therapeutics》2005,28(6):553-557

We examined inhibitory effects of ofloxacin (OFX), orbifloxacin (OBFX), ciprofloxacin (CFX), enrofloxacin (EFX) and norfloxacin (NFX) on cytochrome P-450 1A (CYP1A) activities using hepatic microsomes from four beagle dogs. Ethoxyresorufin O-de-ethylation was referred as CYP1A activities. All the fluoroquinolones inhibited the reaction in a noncompetitive manner. The determined inhibitory constants were the followings; 10.1 +/- 3.8 mM for OFX, 6.43 +/- 2.01 mM for OBFX, 0.726 +/- 0.134 mM for CFX, 4.06 +/- 1.19 mM for EFX and 4.75 +/- 1.63 mM for NFX respectively. As these values are >100-fold of plasma concentrations after a clinical single dose of the fluoroquinolones, it is suggested that the inhibitory effect on CYP1A activities is not so high to elicit drug-drug interaction with CYP1A substrates, when these fluoroquinolones are co-administered. Mechanism based inhibition was also examined in this study. Of the five fluoroquinolones examined, OFX, OBFX and CFX had this inhibition manner. As this inhibition is irreversible, inhibitory effects of the three fluoroquinolones may accumulate, when they are repeatedly administered. Therefore, OFX, OBFX and CFX may result in substantial drug-drug interaction with a CYP1A substrate even in clinical states. As EFX is metabolized to CFX in the body, it may also have the same possibility.  相似文献   

N-acetylglucosaminyltransferase I activity of bovine oviduct epithelial cells: stimulation by luteinizing hormone, vascular endothelial growth factor and tumor necrosis factor alpha     

Nozaki H  Wijayagunawardane MP  Kodituwakku SP  Yoshida T  Nakamura T  Arai I  Urashima T  Miyamoto A 《The Journal of reproduction and development》2005,51(2):229-234

N-acetylglucosaminyltransferase I (GnT I; EC 2.4.1.101), which catalyzes the first step in the conversion of oligomannose to complex or hybrid N-glycans of glycoproteins, was found in media cultured with bovine oviduct epithelial cells (BOEC) obtained from non-pregnant cows during the follicular phase. Combined treatment with specific hormones increased GnT I release from BOEC. Luteinizing hormone (LH; 10 ng/ml) alone slightly, but together with 17beta-estradiol (E2; 1 ng/ml), synergistically increased GnT I activity. Vascular endothelial growth factor (VEGF) and tumor necrosis factor (TNF) alpha, which have been shown to have their highest activities in the bovine oviduct during the periovulatory period, also increased in GnT I activity. This study provides the first evidence of an increase of GnT I release from BOEC in vitro, and shows that endocrine as well as local factors such as LH, VEGF and TNFalpha increase this activity. The results suggest that GnT I activity in the bovine oviduct may contribute to the induction of glycosylation and thereby contributing to the provision of the optimal microenvironment for fertilization and early development of the embryos.  相似文献   

Effects of heat stress on the redox status in the oviduct and early embryonic development in mice     

Matsuzuka T  Ozawa M  Nakamura A  Ushitani A  Hirabayashi M  Kanai Y 《The Journal of reproduction and development》2005,51(2):281-287

This study examined the association between redox status in the oviduct and early embryonic death in heat-stressed mice. In Experiment 1, non-pregnant mice were heat-stressed at 35 C with 60% relative humidity for 12, 24, or 36 h, and the maternal redox status was verified by measuring the levels of reactive oxygen species (ROS) and free radical scavenging activity (FRSA) in the oviduct, and thiobarbituric acid reactive substances (TBARS) and glutathione peroxidase (GSH-Px) activity in the liver. In Experiment 2, zygotes were collected from mice heat-stressed for 12 h on the day of pregnancy, and their developmental abilities were assessed in vitro, along with the intensity of DNA damage at the 2-cell stage. The TBARS value and GSH-Px activity in the liver, and ROS level in the oviduct were significantly higher in heat-stressed mice, and this increase appeared to depend on the duration of the heat stress. Maternal heat stress significantly reduced the percentage of zygotes that developed to the morula and blastocyst and the total cell number in the blastocyst. In addition, DNA damage at the 2-cell stage was significantly higher in maternally heat-stressed embryos. These results suggest that heat stress induces systemic changes in redox status in the maternal body, and the resultant increase in oxidative stress in the oviduct is possibly involved in heat stress-induced early embryonic death .  相似文献