Generation and soil detection of nitrate-nonutilizing mutants of Diaporthe destruens causing foot rot of sweet potato     

Nomiyama  Koji  Tomioka  Keisuke  Nakaho  Kazuhiro 《Journal of General Plant Pathology》2022,88(2):128-133

Journal of General Plant Pathology - Three nitrate-nonutilizing (nit) mutants of a soil-borne fungus, Diaporthe destruens, pathogen of foot rot of sweet potato, were generated with a...  相似文献   

Characterization of a Phytophthora mating hormone     

Qi J  Asano T  Jinno M  Matsui K  Atsumi K  Sakagami Y  Ojika M 《Science (New York, N.Y.)》2005,309(5742):1828

Water molds of the genus Phytophthora include many plant pathogens responsible for epidemics such as potato blight and sudden oak death, causing global economic damages. Sexual reproduction is of biological importance in Phytophthora and has been believed to be stimulated by unknown endogenous factors named a hormones. We describe here the chemical characterization of a Phytophthora mating hormone, a1, which was obtained from approximately 2 tons of culture fluid of one mating type of a species and which induced sexual spores on the counter-mating type at a nanogram level.  相似文献   

A model explaining genotypic and environmental variation in leaf area development of rice based on biomass growth and leaf N accumulation     

Hiroe Yoshida  Takeshi Horie  Keisuke Katsura  Tatsuhiko Shiraiwa 《Field Crops Research》2007

Leaf area index (LAI) is one of the major determinants of crop photosynthesis. The objectives of this study were to clarify the relationship between LAI development and crop growth in diverse rice genotypes grown under widely different climate conditions and to develop a model explaining genotypic and environmental variation in LAI dynamics based on environmental and plant factors. Cross-locational experiments were conducted with nine different rice genotypes at eight locations in Asia covering a wide climate range under irrigated conditions with sufficient nitrogen application. The LAI observed at the heading stage ranged from 0.85 to 8.77 among the genotypes grown at the eight locations. A fairly stable allometric relationship was observed between LAI development and above-ground biomass growth during the period from transplanting to 2 weeks before heading over all the genotypes, sites and years (r = 0.91). The allometric relationship was, however, under the influence of leaf nitrogen content per unit leaf area (LNC, g m⁻² leaf) and air temperature. On the basis of these results, we modeled the LAI development as a function of relative crop growth rate (RGR), LNC and air temperature. The rate of LAI decrease associated with leaf senescence was also described as a function of LNC.  相似文献   

Spontaneous iron accumulation in hepatocytes of a 7-week-old female rat     

Miyata K  Sukata T  Kushida M  Ogata K  Suzuki M  Ozaki M  Ozaki K  Uwagawa S 《Journal of toxicologic pathology》2009,22(3):199-203

Spontaneous iron accumulation in hepatocytes was observed in a 7-week-old female Han Wistar GALAS rat. Very fine yellowish brown pigments, which showed a positive reaction with Berlin Blue stain, were apparent in the cytoplasm close to the bile canaliculi, with a diminishing periportal-to-centrilobular gradient. There were also differences in distribution between and within lobes. Transmission electron microscopy revealed cytosolic ferritin and pericanalicular siderosomes in hepatocytes. No degeneration or necrotic changes were observed, and non-hepatocyte cells did not demonstrate any obvious accumulation of iron. There were no abnormalities in the animal other than this finding in the liver.  相似文献   

No Modifying Effect of Antioxidant N-Acetyl-L-Cysteine on Fenofibrate-induced Hepatocarcinogenesis in Rats     

Nishimura J  Dewa Y  Jin M  Saegusa Y  Kawai M  Kemmochi S  Shimamoto K  Harada T  Itoh T  Shima T  Shibutani M  Mitsumori K 《Journal of toxicologic pathology》2009,22(4):255-261

To clarify the modifying effect of N-Acetyl-L-Cysteine (NAC), which has antioxidative ability, on hepatocarcinogenesis promoted by fenofibrate (FF), a peroxisome proliferator-activated receptor (PPAR) alpha agonist , male F344/N rats were administered a single intraperitoneal injection of N-diethylnitrosamine (DEN) as an initiator followed by administration of a diet containing 3,000 ppm of FF for 16 weeks. Two-thirds partial hepatectomy was performed 1 week after the FF treatment. Additionally, NAC treatments for 14 weeks from 2 weeks after the FF treatment were performed. Although the expression level of tumor protein p53 (Tp53) mRNA decreased in the DEN+FF+NAC group as compared with that in the DEN+FF group, no significant differences between the DEN+FF and DEN+FF+NAC groups were observed in the number of hepatocellular altered foci and activities of hepatocellular proliferation. In addition, the results of an antioxidant enzyme assay and measurement of the amounts of total glutathione in the liver revealed no significant difference between the DEN+FF and DEN+FF+NAC groups; although no significant differences were observed in many genes between the DEN+FF and DEN+FF+NAC groups, only glutathione peroxidase 2 (Gpx2) mRNA increased in the DEN+FF+NAC group as compared with the DEN+FF group. The results under the present experimental conditions indicate no obvious modifying effect of NAC on liver tumor promotion by FF in rats.  相似文献   

Impaired placentomal interferon signaling as the possible cause of retained fetal membrane in parturition-induced cows     

Ryo INABA  Ryouka KAWAHARA-MIKI  Akihisa SHINOZAWA  Taichi YASUHARA  Takashi FUJII  Keisuke KOYAMA  Michiko MURATA-OKUBO  Kousaku SOUMA  Hiroki HIRAYAMA 《The Journal of reproduction and development》2022,68(1):30

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Effects of the preservation medium and storage duration of domestic cat ovaries on the maturational and developmental competence of oocytes in vitro     

Takumi YOSHIDA  Md Emtiaj ALAM  Keisuke HANAFUSA  Yasunori TSUJIMOTO  Masaya TSUKAMOTO  Ryoji KANEGI  Toshio INABA  Kikuya SUGIURA  Shingo HATOYA 《The Journal of reproduction and development》2022,68(2):160

We examined the effectiveness of saline, Euro-Collins solution (EC), and ET-Kyoto solution (ET-K) as preservation media for the cold storage of feline ovaries. Ovaries were maintained in these media at 4°C for 24, 48, or 72 h until oocyte retrieval. The ET-K group exhibited a higher oocyte maturation rate than the saline group after 72 h of storage. Moreover, ET-K could sustain the competence of the feline oocytes to cleave after 48 h, and the morula formation rate of the ET-K group was higher than that of the other groups after 24 and 48 h. Furthermore, the ET-K group exhibited a higher blastocyst formation rate than the other groups after storage for 24 h, and only ET-K retained the developmental competence in blastocysts after 48 h of storage. In addition, regarding the cell numbers of the blastocysts, there was no significant difference among the tested groups. In conclusion, our results indicate that ET-K is a suitable preservation medium for feline ovaries.  相似文献   

Positive phototaxis as the cause of jaw malformations in larval greater amberjack,Seriola dumerili (Risso, 1810): Mitigation by rearing in tanks with low‐brightness walls     

Yoshifumi Sawada  Tsukasa Sasaki  Keisuke Nishio  Michio Kurata  Tomoki Honryo  Yasuo Agawa 《Aquaculture Research》2020,51(6):2261-2274

Jaw malformations are a serious problem in fingerlings of the greater amberjack, Seriola dumerili. To establish a countermeasure against these malformations, we conducted a larval behavioural test to identify their root cause, and we investigated the ability of low‐brightness rearing tank walls to control their occurrence. Larval distribution was examined in a horizontally illuminated rectangular transparent aquarium (20 cm × 100 cm × 25 cm), and their distribution was biased towards the light source after this lighting was provided from 3 to 13 days post hatching (dph), indicating positive phototaxis; this response disappeared on 22 dph (there are no data between 13 and 22 dph). Larvae were observed to swim phototactically towards the light source and repeatedly collided with the tank wall (walling behaviour). To investigate the ability of wall brightness to control the incidence of jaw malformations, we compared their incidence in a rearing trial with different Munsell colour values for the tank walls: 2.11 (black), 5.85 (grey) and 9.52 (white). The incidence rate of jaw malformations at 25 dph was significantly lower in the tanks with lower‐brightness walls, that is, 5.8%, 22.5% and 26.8% for black, grey and white respectively. Larval walling behaviour was most intense for white, followed in order by grey and black. These results indicate that positive phototaxis elicits larval walling behaviour, causing jaw malformations, and that low‐brightness tank walls control this process.  相似文献   

In vitro induction of oocyte maturation in the Japanese sea cucumber Apostichopus japonicus by cubifrin and the developmental ability of the eggs     

Keisuke Yamano  Atushi Fujiwara  Akifumi Nakamura  Michiyasu Yoshikuni 《Fisheries Science》2013,79(5):823-832

We describe the process of cubifrin-induced in vitro oocyte maturation in the Japanese sea cucumber Apostichopus japonicus, and we propose a procedure for practical hatchery application. Oocyte maturation occurred 40–50 min after stimulation of the ovaries by cubifrin. Concurrently, eggs were released from the ovarian tubules, initially by slow peristalsis, followed by active release after about 60 min. The first and second polar bodies were released from the eggs at 90–100 min and about 140 min, respectively. Cubifrin was more effective in inducing oocyte maturation at 1–100 nM than at 100 pM. Cubifrin at 1 pM–10 nM in rearing seawater had no effect on larval development. Delayed fertilization reduced the developmental ability of eggs. Broodstock could be maintained at 15–16 °C for up to about 50 days without affecting the developmental ability of eggs. Eggs matured in vitro and in vivo were similar in their developmental ability. In conclusion, the in vitro induction of oocyte maturation is effective in Japanese sea cucumber and represents a viable alternative to the induction of spawning by cubifrin injection.  相似文献   

Food habits of small fishes in seagrass habitats in Trang,southern Thailand     

Masahiro Horinouchi  Prasert Tongnunui  Keisuke Furumitsu  Yohei Nakamura  Kouki Kanou  Atsuko Yamaguchi  Ken Okamoto  Mitsuhiko Sano 《Fisheries Science》2012,78(3):577-587

To clarify the feeding habits of seagrass fishes, we examined the gut contents from 42 fish species collected in seagrass habitats in Trang. Thirteen species showed ontogenetic and/or seasonal changes in food-use patterns. Smaller individuals generally preyed on small planktonic items (e.g., copepod larvae) or small benthic/epiphytic crustaceans (e.g., harpacticoid copepods), with subsequent changes to other prey items (e.g., shrimps, crabs, detritus and filamentous algae) with growth. The most important dietary items for the seagrass fish assemblages comprised benthic/epiphytic crustaceans, detritus, and planktonic copepods. Cluster analysis based on dietary overlaps showed that the seagrass fishes comprised eight feeding guilds (large benthic/epiphytic crustacean, detritus, planktonic animal, small benthic/epiphytic crustacean, mollusc, invertebrate egg, polychaete, and fish feeders). Of these, the first three guilds were the most abundantly represented, whereas the last three were each represented by only a single species.  相似文献