Different longitudinal distribution patterns of native white-spotted charr and non-native brown trout in Monbetsu stream, Hokkaido, northern Japan     

K. Hasegawa  K. Maekawa 《Ecology of Freshwater Fish》2008,17(1):189-192

Abstract  This study focused on longitudinal distribution patterns of native white-spotted charr and non-native brown trout in a mountainous stream in Hokkaido, Japan. Brown trout ratio, which is the proportion of brown trout in the catch of salmonids, was decreasing from downstream to upstream. Brown trout ratio correlated negatively with water temperature. Thus, our results suggested that temperature may influence the possible competition between native white-spotted charr and non-native brown trout.  相似文献   

Suppressive effect of liquid potassium silicate on powdery mildew of strawberry in soil   总被引：3，自引：0，他引：3  

Takeshi Kanto  Akihiro Miyoshi  Takuya Ogawa  Kazumasa Maekawa  Masataka Aino 《Journal of General Plant Pathology》2006,72(3):137-142

A soil drench of soluble silicon (liquid potassium silicate) was tested for the control of powdery mildew of strawberry in soil for 2 years in a vinyl house under growers' conditions on two cultivars: very susceptible Toyonoka and slightly susceptible Sachinoka. Soluble silicon suppressed the disease more effectively as a preventive control than as a control to reduce initial incidence. The suppressive effect against this disease was more effective for Toyonoka than for Sachinoka. The control value of soluble potassium silicate was 85.6% for Toyonoka in the first year and 60.2% in the second year, while for Sachinoka it was 58% in the first year and 40.6% in the second year. Strawberry leaf hardness was measured for the control and silicate-treated leaves. Although silicate-treated leaves seemed to be harder than control leaves, leaf hardness did not vary significantly between controls and silicate-treated leaves in either of the 2 years, and the mode of preventive action of liquid potassium silicate remains unknown. A factor other than a physical action may be involved.  相似文献   

Does actor power impede outcomes in participatory agroforestry approach? Evidence from Sal forests area,Bangladesh     

K. K. Islam  S. Jose  Masakazu Tani  Kimihiko Hyakumura  Max Krott  Noriko Sato 《Agroforestry Systems》2015,89(5):885-899

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Female-biased mortality rate and sexual size dimorphism of migratory masu salmon, Oncorhynchus masou   总被引：1，自引：0，他引：1  

T. Tamate  K. Maekawa 《Ecology of Freshwater Fish》2004,13(2):96-103

Abstract –  We examined whether mortality and growth during the migration phase (the lacustrine phase after smolting) differ between sexes in migratory (lake-run) masu salmon ( Oncorhynchus masou ) in a lacustrine population, northern Hokkaido, Japan. The sex ratio of 1+ smolts was more skewed to females than that of the returning adults in three annual cohorts examined, indicating that females have a higher mortality rate during the migration phase. Although there was no difference in smolt length between sexes, female adults were larger in body length than males of the same age: female-biased sexual size dimorphism (SSD) occurs. We suppose that breeding selection favouring a larger body size for females than for males in this population probably requires that females undertake more intensive foraging behaviour with its greater inherent risks but faster growth rates during the migration phase. It therefore seems to be likely that the selection is the ultimate cause of the female-biased mortality rate and SSD.  相似文献   

The role of the anal fin in fertilization success in male medaka, Oryzias latipes     

Yusuke Koseki  Keisuke Takata and  Koji Maekawa 《Fisheries Science》2000,66(4):633-635

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‘Slippage’ in the Implementation of Forest Policy by Local Officials: A Case Study of a Protected Area Management in Lao PDR     

Kimihiko Hyakumura 《Small-Scale Forestry》2010,9(3):349-367

A progressive part of protected area management program in Lao PDR is a land and forest allocation program which contains critical elements that delegate right of land and forest use to local people. This study analyzes the gap between the original intent of the program and its actual implementation by local officials in Phou Xang He protected area, and discusses policy issues that need to be addressed. It appears that several types of non-compliance with regulations by local people have occurred, with local officials tacitly ignoring infractions. By switching viewpoints, however, it appears that the local officials permit these infractions as a way of allowing local people to secure their livelihoods. As constraints on the realities of land and forest use vary widely in and around villages in different locales, there is a need for government to allow local officials flexibility in implementing policies.  相似文献   

Chromosomes responsible for sensitivity of embryo to abscisic acid and dormancy in wheat   总被引：4，自引：0，他引：4  

Kazuhiko Noda  Takakazu Matsuura  Masahiko Maekawa  Shin Taketa 《Euphytica》2002,123(2):203-209

The sensitivity of the embryo to abscisic acid (ABA) has been reported toplay an important role in seed dormancy. Using ditelocentric lines of wheatcv. Chinese Spring (CS, nondormant and ABA insensitive), F₂ seedsbetween monosomic lines of CS and a wheat line Kitakei-1354 (dormant,ABA sensitive) and deletion lines of CS chromosome 4A, germinability ofseeds and embryo-half seeds incubated in water and ABA were examined. The results indicated that the long arm of chromosome 4A carried majorgene(s) for the embryo sensitivity to ABA and dormancy. Chromosome2D might be also involved in the sensitivity to ABA.  相似文献   

Synthesis of morphiceptin (Tyr-Pro-Phe-Pro-NH(2)) by dipeptidyl aminopeptidase IV derived from Aspergillus oryzae     

Ota T  Itoh A  Tachi H  Kudoh K  Watanabe T  Yamamoto Y  Tadokoro T  Maekawa A 《Journal of agricultural and food chemistry》2005,53(15):6112-6116

Morphiceptin (Tyr-Pro-Phe-Pro-NH(2)), tetrapeptide, was synthesized using dipeptidyl aminopeptidase IV (DP IV, EC 3.4.14.5) derived from Aspergillus oryzae RIB 915 as a catalyst. Tyr-Pro-OEt was incubated with Phe-Pro-NH(2) in the presence of DP IV under various conditions of temperature, concentrations of ethylene glycol, pH, reaction time, and others. Morphiceptin was obtained at 40% yield under the optimal reaction conditions: substrate, 4 mM Tyr-Pro-OEt.HCl and 20 mM Phe-Pro-NH(2).HCl; enzyme, DP IV, 0.275 nkat; solvent, 60% ethylene glycol containing 20 mM phosphate buffer at pH 7.0; amine, 4.2 mM diisopropylamine at 4 degrees C for 24 h. Amino group protection was unnecessary for synthesis of morphiceptin by DP IV.  相似文献   

Oxidative activation of O,S-dimethyl phosphoramidothiolate     

Morifusa Eto  Sachiko Okabe  Yoshihisa Ozoe  Kazuyuki Maekawa 《Pesticide biochemistry and physiology》1977,7(4):367-377

O,S-Dimethyl phosphoramidothiolate, the insecticide methamidophos, is converted oxidatively into a potent anti-cholinesterase agent by the action of m-chloroperbenzoic acid. The active intermediate is not stable enough to be isolated. From some chemical evidence, the sulfoxide, i.e., dimethyl phosphoramidothiolate S-oxide, is most probably the active intermediate. A similar activation may occur by biological oxidation.  相似文献   

Suppressive effect of potassium silicate on powdery mildew of strawberry in hydroponics   总被引：1，自引：0，他引：1  

Takeshi?KantoEmail author  Akihiro?Miyoshi  Takuya?Ogawa  Kazumasa?Maekawa  Masataka?Aino 《Journal of General Plant Pathology》2004,70(4):207-211

From 1996 to 1997, potassium silicate (SiO₂) was tested at 0, 25, 50, and 100mgl^–1 in hydroponics to control powdery mildew. Other elements were added in the usual amounts, and the strawberries were cultivated hydroponically in a greenhouse for 4 months (from October to January). The powdery mildew spread in the control plot, but little mildew developed in the plot with 25mgl^–1 silicate, and none in plots with more than 50mgl^–1 silicate. The suppressive effect lasted for about 4 months on fruits and even longer on leaves. On analysis of mineral content in the leaves, only the silicate content differed markedly between the control and treated plants. Nitrogen, phosphate, potassium, and calcium contents did not differ greatly. The maximum silicate content was about 24 times that of the control, and disease severity decreased significantly when the content was more than 1.5% in the leaves. The hardness of the strawberry leaves, measured by a creep meter, was increased by the silicate treatment.  相似文献