Social contributions of plant pathology with special focus on plant disease control     

Katsuyoshi Yoneyama 《Journal of General Plant Pathology》2004,70(6):376-378

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Inhibitory and promotive allelopathy in rice (Oryza sativa L.)   总被引：2，自引：1，他引：2  

Yasutomo Takeuchi  Shun Kawaguchi†  Koichi Yoneyama 《Weed Biology and Management》2001,1(3):147-156

Studies on allelopathic rice, which inhibits the germination and development of weeds such as barnyardgrass ( Echinochloa spp.) and ducksalad [ Heteranthera limosa (Sw.) Wild.], have been strongly conducted in the USA, the Philippines, Japan, Korea, and other countries since the 1980s. Weed-suppressing rice plants can compete with weeds for light and mineral nutrients by their rapid and thick growth characteristics, and probably also by their allelopathic effects. It was suggested that allelopathic properties were inherited from parents. Different screening methods for finding allelopathic rice simply and rapidly have been proposed. In contrast, stimulative allelopathy in rice, which promotes germination of the dormant and dormancy-awakened seeds of Monochoria vaginalis (Burm. f.) Kunth var. vaginalis , has been investigated by the authors since the 1990s. Rice seeds promoted the germination in the dark and in light under submerged conditions. Our experiments suggested that rice seeds, hulls, plants and straw contain stimulative substance(s) that promote seed germination of M. vaginalis .  相似文献   

A specific and potent inhibitor of brassinosteroid biosynthesis possessing a dioxolane ring     

Sekimata K  Han SY  Yoneyama K  Takeuchi Y  Yoshida S  Asami T 《Journal of agricultural and food chemistry》2002,50(12):3486-3490

Screening for brassinosteroid biosynthesis inhibitors was performed to find azole derivatives that induced dwarfism, to resemble brassinosteroid-deficient mutants in Arabidopsis, and which could be rescued by brassinosteroid. Through this screening experiment, propiconazole fungicide was selected as a likely inhibitor of brassinosteroid biosynthesis and, thus, propiconazole derivatives with optimized activity and selectivity were synthesized. The biological activity of these compounds was evaluated by examining cress stem elongation. Among the compounds tested, 2RS,4RS-1-[2-(4-trifluoromethylphenyl)-4-n-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazole (12) showed the most potent capability to retard cress stem elongation in the light. The compound-induced hypocotyl dwarfism was restored by the coapplication of 10 nM brassinolide but not by 1 microM gibberellin. These results suggest that 12 should affect brassinosteroid biosynthesis. The potency and specificity of 12 were greater than those of brassinazole, a previously reported brassinosteroid biosynthesis inhibitor.  相似文献   

Analysis of strigolactones,germination stimulants for striga and orobanche,by high-performance liquid chromatography/tandem mass spectrometry     

Sato D  Awad AA  Chae SH  Yokota T  Sugimoto Y  Takeuchi Y  Yoneyama K 《Journal of agricultural and food chemistry》2003,51(5):1162-1168

A simple and rapid analytical method for strigolactones, germination stimulants for the root parasitic weeds witchweed (Striga spp.) and broomrape (Orobanche spp.), has been developed using high-performance liquid chromatography connected to tandem mass spectrometry (LC/MS/MS). The natural strigolactones (strigol, sorgolactone, orobanchol, and alectrol) were clearly separated and identified by LC/MS/MS. As low as 0.1 pg/microL of strigol and 0.5 pg/microL of sorgolactone could be quantified, whereas 1 pg/microL was needed for the quantification of orobanchol (S/N > 10). Using this method, it was found that red clover produces orobanchol and alectrol but not strigol. The roots of red clover seedlings were found to produce 13, 70, 58, and 65 pg of orobanchol/plant 1, 2, 3, and 4 weeks after germination, respectively.  相似文献   

Effects of citric acid on the viscoelasticity of cornstarch pastes     

Hirashima M  Takahashi R  Nishinari K 《Journal of agricultural and food chemistry》2004,52(10):2929-2933

The effects of citric acid on the rheological properties of cornstarch pastes were studied by steady shear and dynamic oscillatory viscoelasticity, intrinsic viscosity measurements and microscopic observation. The pH of cornstarch dispersion was adjusted between 6.0 and 3.0. The viscosity of the pastes was increased by lowering the pH (between 5.5 and 3.6), while the viscosity of samples with pH below 3.5 decreased further than that of the control (pH = 6.3). Citric acid promoted the collapse of starch granules; however, adding excessive citric acid led to the hydrolysis of glucose chains. No decrease in the viscoelasticity was observed for cornstarch pastes by adding acid at 25 degrees C after gelatinization.  相似文献   

Effects of dihydroheptaprenol on neutrophil functions in calves   总被引：1，自引：0，他引：1  

O Yoneyama  S Osame  S Ichijo  M Kimura  S Araki  M Suzuki  E Imamura 《The British veterinary journal》1989,145(6):531-537

Microemulsified dihydroheptaprenol (DHP) was administered intramuscularly to clinically healthy calves at doses of 4, 6 and 8 mg/kg body weight. Marked increase of neutrophil counts was observed 0.5, 1 and 2 days after the injection at a dose of 6 mg/kg. Nitroblue tetrazolium reducing activity of neutrophils was also obviously enhanced 1, 2 and 3 days after DHP administration. Phagocytic killing of Staphylococcus aureus by neutrophils was further enhanced markedly 1, 2 and 3 days after the drug injection at 6 mg/kg.  相似文献   

Chemerin analog regulates energy metabolism in sheep     

Yutaka SUZUKI  Sang‐Houn SONG  Katsuyoshi SATO  Kyoung‐Ha SO  Astrid ARDIYANTI  Shun KITAYAMA  Yeon‐Hee HONG  Sung‐Dae LEE  Ki‐Choon CHOI  Akihiko HAGINO  Kazuo KATOH  Sang‐gun ROH 《Animal Science Journal》2012,83(3):263-267

Accumulating data suggest a relationship between chemerin and energy metabolism. Our group previously described gene cloning, expression analysis and the regulatory mechanism of chemerin and its own receptor in mice and cattle. The objective of the present study was to investigate the physiological effect of chemerin on endocrine changes and energy metabolism in sheep using a biologically stable chemerin analog. The chemerin analog was intravenously administrated (100 or 500 µg/head) to sheep, and plasma insulin and metabolites (glucose, nonesterified fatty acids (NEFA), triglyceride, total cholesterol and high‐density lipoprotein (HDL) cholesterol) were analyzed. The chemerin analog dramatically increased the insulin levels, and glucose levels were decreased. NEFA levels were slightly decreased at 20 min but then increased gradually from 60 to 180 min after analog administration. In addition, injection of the chemerin analog immediately increased triglyceride and total cholesterol but not HDL levels. These results suggested that chemerin analog regulated insulin secretion related to glucose metabolism and the release of triglycerides in sheep in vivo. This study provides new information about endocrine and metabolic changes in response to chemerin in sheep.  相似文献   

Parasitic weed management by using strigolactone‐degrading fungi          下载免费PDF全文

Angela Boari  Biancamaria Ciasca  Rocío Pineda‐Martos  Veronica MT Lattanzio  Koichi Yoneyama  Maurizio Vurro 《Pest management science》2016,72(11):2043-2047

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Mechanism of the rice hull‐induced germination of Monochoria vaginalis seeds in darkness     

Takao Yokota  Hiromi Handa  Yumiko Yamada  Koichi Yoneyama  Yasutomo Takeuchi 《Weed Biology and Management》2014,14(2):138-144

The seeds of Monochoria vaginalis require light to germinate. However, they are able to germinate in darkness in the presence of rice hulls. The mechanism of this phenomenon was investigated in this study, in which only the unsterilized seeds of Monochoria were induced to germinate by the presence of a rice hull extract. The rice hull extract was able to be replaced by either a mixture of amino acids and phosphate or a yeast extract. The culture media in which germination was observed always showed turbidity, indicating the propagation of bacteria, which were identified as Bacillus sp., Pedobacter sp., Pantoea sp. and Sphingomonas sp. Treatment with the individual bacterial species or combinations of these bacteria induced Monochoria seed germination when added to the media containing the rice hull extract. It was concluded that the rice hull extract accelerates the propagation of bacteria, which in turn digest the seed coat of Monochoria, facilitating its germination.  相似文献   

Effects of sika deer (Cervus nippon) and dwarf bamboo (Sasamorpha borealis) on seedling emergence and survival in cool-temperate mixed forests in the Kyushu Mountains     

Ikue Murata  Sigefumi Saruki  Katsuyoshi Kubota  Sachiko Inoue  Naoaki Tashiro  Tsutomu Enoki  Yasuhiro Utsumi  Susumu Inoue 《Journal of Forest Research》2009,14(5):296-301

Effects of sika deer (Cervus nippon) and dwarf bamboo (“sasa;” Sasamorpha borealis) on seedling emergence and survival were investigated in cool-temperate mixed forests in the Kyushu mountain range, Japan. We compared the effects of sika deer between two sites with different sika deer densities. One site (no-sasa forest) has sparse cover of S. borealis and a high density of sika deer, and the other site (sasa forest) has dense cover of S. borealis with a low density of sika deer. In the no-sasa forest, more seedlings emerged and the survival rate of the seedlings was higher compared with the sasa forest. Compared with the sasa forest, the canopy in the no-sasa forest was more open, the organic layer was shallower and drier, the mean daily soil temperature was higher, and soil temperature fluctuated more widely. Those environmental parameters did not differ between unfenced and fenced plots. The comparison between the sasa and no-sasa forests suggested that removal of S. borealis by sika deer had an indirect positive effect on seedling emergence and survival. However, the fenced-plot experiments indicated that sika deer inhibited seedling emergence and survival. These contradictory conclusions could result from the much larger negative effects of S. borealis on seedling emergence and survival compared with the effects of sika deer browsing.  相似文献