Succession and phylogenetic composition of eubacterial communities in rice straw during decomposition on the surface of paddy field soil     

Naoko ASARI  Rie ISHIHARA  Yasunori NAKAJIMA  Makoto KIMURA  Susumu ASAKAWA 《Soil Science and Plant Nutrition》2007,53(1):56-65

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Antioxidative compounds from the outer scales of onion   总被引：2，自引：0，他引：2  

Ly TN  Hazama C  Shimoyamada M  Ando H  Kato K  Yamauchi R 《Journal of agricultural and food chemistry》2005,53(21):8183-8189

Antioxidative compounds were isolated from the methanol extract of dry outer scales of onion (Allium cepa L.). Nine phenolic compounds (1-9) were finally obtained by reversed-phase high-performance liquid chromatography, and their structures were elucidated by NMR and mass spectrometry analyses. They were the six known compounds, protocatechuic acid (1), 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (2), quercetin 4'-O-beta-D-glucopyranoside (3), quercetin (5), 4'-O-beta-d-glucopyranoside of quercetin dimer (7), and quercetin dimer (8), and three novel compounds, condensation products of quercetin with protocatechuic acid (4), adduct of quercetin with quercetin 4'-O-beta-D-glucopyranoside (6), and quercetin trimer (9). These phenolic compounds were tested for their antioxidant properties using autoxidation of methyl linoleate in bulk phase or free radical initiated peroxidation of soybean phosphatidylcholine in liposomes. The flavonoid compounds having o-dihydroxy substituent in the B-ring were shown to be effective antioxidants against nonenzymic lipid peroxidation.  相似文献   

Populations, Community Composition and Biomass of Aquatic Organisms in the Floodwater of Rice Fields and Effects of Field Management     

Makoto Kimura 《Soil Science and Plant Nutrition》2005,51(2):159-181

As rice fields are managed for improved rice production, many studies on aquatic organisms in the floodwater have been restricted to agronomically important members such as blue-green algae (BGA) and Azolla , and ecological studies on common aquatic organisms were relatively limited to specific group members. In the present paper, studies on all the aquatic organisms in the floodwater, from protozoa to insects and fishes, were reviewed worldwide from the viewpoint of rice field ecology, paying attention to their populations, seasonal variations, antagonistic relations and biomass, and the effect of field management. Most studies conducted in India and in the Southeast Asian countries dealt with the BGA and green algal populations. In contrast, protozoa and aquatic animals were extensively studied in rice fields in Europe. Japanese studies in the past were intermediate between the previously cited studies. They generally described specific groups depending on the authors' interests, and surprisingly few studies dealt with the community level and prey-predator relationships. Field management such as fertilizer and pesticide application, water management and plowing was found to play a major role in determining the populations of aquatic organisms. Overview of research on aquatic organisms in the floodwater of rice fields suggests several directions for future studies.  相似文献   

Isolation and characterization of some antioxidative compounds from the rhizomes of smaller galanga (Alpinia officinarum Hance)   总被引：2，自引：0，他引：2  

Ly TN  Shimoyamada M  Kato K  Yamauchi R 《Journal of agricultural and food chemistry》2003,51(17):4924-4929

Antioxidative compounds were isolated from the methanol extract of fresh rhizome of smaller galanga (Alpinia officinarum Hance). Seven phenylpropanoids (1-7) were finally obtained by reversed-phase HPLC, and their structures were elucidated by MS and NMR analyses. They comprised the two known compounds, (E)-p-coumaryl alcohol gamma-O-methyl ether (1) and (E)-p-coumaryl alcohol (6), and the five novel compounds, stereoisomers of (4E)-1,5-bis(4-hydroxyphenyl)-1-methoxy-2-(methoxymethyl)-4-pentene (2a and 2b), stereoisomers of (4E)-1,5-bis(4-hydroxyphenyl)-1-ethoxy-2-(methoxymethyl)-4-pentene (3a and 3b), (4E)-1,5-bis(4-hydroxyphenyl)-1-[(2E)-3-(4-acetoxyphenyl)-2-propenoxy]-2-(methoxymethyl)-4-pentene (4), (4E)-1,5-bis(4-hydroxyphenyl)-2-(methoxymethyl)-4-penten-1-ol (5), and (4E)-1,5-bis(4-hydroxyphenyl)-2-(hydroxymethyl)-4-penten-1-ol (7). Compounds 1-7 were detected for the first time as constituents of galanga rhizomes and exhibited antioxidative activities against the autoxidation of methyl linoleate in bulk phase.  相似文献   

Genetic tracing shows segregation of taste neuronal circuitries for bitter and sweet     

Sugita M  Shiba Y 《Science (New York, N.Y.)》2005,309(5735):781-785

The recent discovery of mammalian bitter, sweet, and umami taste receptors indicates how the different taste qualities are encoded at the periphery. However, taste representations in the brain remain elusive. We used a genetic approach to visualize the neuronal circuitries of bitter and sweet tastes in mice to gain insight into how taste recognition is accomplished in the brain. By selectively expressing a transsynaptic tracer in either bitter- or sweet and/or umami-responsive taste receptor cells, and by comparing the locations of the tracer-labeled neurons in the brain, our data revealed the potential neuronal bases that underlie discrimination of bitter versus sweet.  相似文献   

The crystal structure of a sodium galactose transporter reveals mechanistic insights into Na+/sugar symport     

Faham S  Watanabe A  Besserer GM  Cascio D  Specht A  Hirayama BA  Wright EM  Abramson J 《Science (New York, N.Y.)》2008,321(5890):810-814

Membrane transporters that use energy stored in sodium gradients to drive nutrients into cells constitute a major class of proteins. We report the crystal structure of a member of the solute sodium symporters (SSS), the Vibrio parahaemolyticus sodium/galactose symporter (vSGLT). The approximately 3.0 angstrom structure contains 14 transmembrane (TM) helices in an inward-facing conformation with a core structure of inverted repeats of 5 TM helices (TM2 to TM6 and TM7 to TM11). Galactose is bound in the center of the core, occluded from the outside solutions by hydrophobic residues. Surprisingly, the architecture of the core is similar to that of the leucine transporter (LeuT) from a different gene family. Modeling the outward-facing conformation based on the LeuT structure, in conjunction with biophysical data, provides insight into structural rearrangements for active transport.  相似文献   

The yohkoh mission for high-energy solar physics     

Acton L  Bruner M  Lemen J  Tsuneta S  Ogawara Y  Nishimura J  Bentley R  Culhane L  Canfield R  Hudson H  Doschek G  Hiei E  Hirayama T  Kosugi T  Watanabe T  Lang J  Makishima K  Uchida Y 《Science (New York, N.Y.)》1992,258(5082):618-625

The Japanese Yohkoh satellite is now in orbit observing the sun with a set of x-ray imagers and x-ray and gamma-ray spectrometers. The data from this successful mission provide new information on solar flares and the sun's corona. This paper discusses the Yohkoh observations and presents a sample of the first scientific results from the mission.  相似文献   

CTLA-4 control over Foxp3+ regulatory T cell function   总被引：1，自引：0，他引：1  

Wing K  Onishi Y  Prieto-Martin P  Yamaguchi T  Miyara M  Fehervari Z  Nomura T  Sakaguchi S 《Science (New York, N.Y.)》2008,322(5899):271-275

Naturally occurring Foxp3+CD4+ regulatory T cells (Tregs) are essential for maintaining immunological self-tolerance and immune homeostasis. Here, we show that a specific deficiency of cytotoxic T lymphocyte antigen 4 (CTLA-4) in Tregs results in spontaneous development of systemic lymphoproliferation, fatal T cell-mediated autoimmune disease, and hyperproduction of immunoglobulin E in mice, and it also produces potent tumor immunity. Treg-specific CTLA-4 deficiency impairs in vivo and in vitro suppressive function of Tregs-in particular, Treg-mediated down-regulation of CD80 and CD86 expression on dendritic cells. Thus, natural Tregs may critically require CTLA-4 to suppress immune responses by affecting the potency of antigen-presenting cells to activate other T cells.  相似文献   

Cytokinin oxidase regulates rice grain production   总被引：25，自引：0，他引：25  

Ashikari M  Sakakibara H  Lin S  Yamamoto T  Takashi T  Nishimura A  Angeles ER  Qian Q  Kitano H  Matsuoka M 《Science (New York, N.Y.)》2005,309(5735):741-745

Most agriculturally important traits are regulated by genes known as quantitative trait loci (QTLs) derived from natural allelic variations. We here show that a QTL that increases grain productivity in rice, Gn1a, is a gene for cytokinin oxidase/dehydrogenase (OsCKX2), an enzyme that degrades the phytohormone cytokinin. Reduced expression of OsCKX2 causes cytokinin accumulation in inflorescence meristems and increases the number of reproductive organs, resulting in enhanced grain yield. QTL pyramiding to combine loci for grain number and plant height in the same genetic background generated lines exhibiting both beneficial traits. These results provide a strategy for tailormade crop improvement.  相似文献   

6─氨基己酸二聚体水解酶基因在异源宿主中的表达     

周泽扬  下坂诚  崎光雄 《西南大学学报(自然科学版)》1996,(2)

将起源于黄色菌（Ｆｌａｖｏｂａｃｔｅｒｉｕｍｓｐ．ＫＩ７２）的６─氨基己酸二聚体水解酶（ＥⅡ）基因以质粒ｐＴＳ１２０９为载体，转入假单孢菌ＰｓｅｕｄｏｍｏｎａｓｐｕｔｉｄａＮＴ１１２６中，得到具有ＥⅡ高表达活性转基因株，表明以假单胞菌为宿主进行ＥⅡ酶分子育种的可行性，并为ＥⅡ酶尚处于进化中的推论提供了旁证。  相似文献