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991.
Shimoyamada M Tômatsu K Oku S Watanabe K 《Journal of agricultural and food chemistry》2000,48(7):2775-2779
To estimate the interactions forming in soymilk freeze-gel, lyophilized gel was extracted successively with various solvents. A mixture of urea, sodium dodecyl sulfate (SDS), and 2-mercaptoethanol (2-ME) dissolved the proteins effectively. The thiol-disulfide exchange reactions and hydrophobic interactions were shown to have a complex relation with a three-dimensional network. The addition of SDS or 2-ME resulted in an incomplete gel or no precipitation of soymilk. In our previous paper (Shimoyamada et al. Food Sci. Technol. Res. 1999, 5, 284-288), the significance of precooling to form small, homogeneously distributed ice crystals in soymilk was reported. In this study, precooling was shown to maintain the partially denatured structures of soybean proteins in soymilk that had unfolded due to heat treatment. These phenomena were considered to be other important functions of precooling in freeze-gelation. 相似文献
992.
Maki Hideaki Utsumi Mao Koshikawa Hiroshi Hiwatari Takehiko Kohata Kunio Uchiyama Hiroo Suzuki Masahiro Noguchi Takuya Yamasaki Tomio Furuki Masakzu Watanabe Masataka 《Water, air, and soil pollution》2003,145(1-4):123-138
We performed a field experiment in thebiodegradation of heavy oil spilled from the Russian tankerNakhodka on a beach in the Sea of Japan. We collectedoil-contaminated cobbles and treated half with nitrogen andphosphorus slow-release fertilizers to stimulate microbialdegradation of the oil; the other half acted as unfertilizedcontrols. The cobbles were placed in porous acrylic vessels andsubmerged. We monitored changes in the oils, macronutrients,microbial community structure and amount of chlorophyll a. There were no significant differences in these criteriabetween the fertilized and unfertilized vessels, apart from anincrease in chlorophyll a in the fertilized vessels.However, there was a major intrinsic degradation of semi-volatile oil compounds in the unfertilized vessels; this occurred at a rate similar to that in the fertilized vessels, despite the low concentration of macronutrients in the seawater at the site. 相似文献
993.
Effect of grazer regulation and algal inoculation on photodependent nitrogen fixation in a wetland rice field 总被引:1,自引:0,他引:1
Summary A dry season field experiment conducted for two consecutive years highlighted problems of achieving increased populations of N2-fixing blue-green algae (BGA) in wetland rice fields. Inoculation of non-indigenous BGA strains, either dried or as fresh viable inocula even at high levels of application, was unsuccessful. A limiting effect of grazing invertebrate populations on BGA establishment was evident, but other factors were involved. Reducing grazer pressure did not permit establishment of inoculated BGA; interspecific competition and environmental factors may explain the inoculation failure. Grazer regulation permitted the establishment of a fast-growing indigenous N2-fixing Anabaena and the doubling of N2-fixing activity over a control. Neither inoculation nor grazer control affected grain yields significantly. 相似文献
994.
Summary Laboratory cultures, soil cultures, and natural samples of N2-fixing blue-green algae (BGA) from rice fields were analyzed for dry matter, ash, N, C, P, and a few other constituents.Results show a very large variability of the composition. Dry matter contents ranged from 0.28% to 13.6% (average 3.3%). Ash contents ranged from 15.6% to 71.3%. Nitrogen contents ranged from 1.9% to 11.8% on an ash-free basis (average 6%). Carbon content was less variable, ranging from 37% to 72% and averaging 43.7%.A decrease in N and pigment contents, and an increase in reducing sugars, was observed in aging laboratory cultures.Large differences in composition were observed between field samples and material grown in artificial medium. Soil-grown BGA and field samples were characterized by very high ash contents, N contents lower than those in laboratory cultures, and P deficiency.Extrapolation from (1) average dry matter, ash, and N contents and (2) records of BGA biomass in rice fields indicates that an algal bloom has a potentiality of about 15–25 kg N per hectare and that a BGA biomass of agronomic significance is visible to the naked eye. 相似文献
995.
Sawai Y Moon JH Sakata K Watanabe N 《Journal of agricultural and food chemistry》2005,53(9):3598-3604
Tea (Camellia sinensis) leaves contain various antioxidants such as ascorbic acid (1) and polyphenols. This study tries to clarify the molecular mechanisms underlying the antioxidative and radical-scavenging activities of these antioxidants, and the reactivities of each antioxidant have been compared against that of the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH, 2) using nuclear magnetic resonance (NMR) analysis. Catechol (3) and (+)-taxifolin (4) were oxidized to o-quinone by 2. However, ethyl protocatechuate (5) and quercetin (6) were not oxidized to o-quinone, even though they possess a catechol structure. The radical-scavenging ability of o-dihydroxyl phenolic compounds with a conjugated olefinic double bond (e.g., 6) was superior to that of compounds without this bond (e.g., 4), whereas the ability of o-dihydroxyl phenolic compounds possessing a conjugated carbonyl bond (5) was inferior to that of compounds lacking this bond (3). Vicinal trihydroxyl phenolic compounds with a conjugated olefinic double bond [e.g., myricetin (7)] had an inferior scavenging ability as compared with compounds lacking this bond [e.g., pyrogallol (8)], but 7 was a better scavenger than compounds with a conjugated carbonyl double bond [e.g., ethyl gallate (9)]. In addition, vicinal trihydroxyl phenolic compounds (e.g., 9) were superior to o-dihydroxyl phenolic compounds (e.g., 6). Finally, 1 scavenged radicals more quickly than 8. 相似文献
996.
Summary A spontaneous mutant ofAzospirillum lipoferum, resistant to streptomycin and rifampicin, was inoculated into the soil immediately before and 10 days after transplanting of rice (Oryza sativa L.). Two rice varieties with high and low nitrogen-fixing supporting traits, Hua-chou-chi-mo-mor (Hua) and OS4, were used for the plant bacterial interaction study. The effect of inoculation on growth and grain and dry matter yields was evaluated in relation to nitrogen fixation, by in situ acetylene reduction assay,15N2 feeding and15N dilution techniques. A survey of the population of marker bacteria at maximum tillering, booting and heading revealed poor effectivety. The population of nativeAzospirillum followed no definite pattern. Acetylene-reducing activity (ARA) did not differ due to inoculation at two early stages but decreased in the inoculated plants at heading. In contrast, inoculation increased tiller number, plant height of Hua and early reproductive growth of both varieties. Grain yield of both varieties significantly increased along with the dry matter. Total N also increased in inoculated plants, which was less compared with dry matter increase.15N2 feeding of OS4 at heading showed more15N2 incorporation in the control than in the inoculated plants. The ARA,15N and N balance studies did not provide clear evidence that the promotion of growth and nitrogen uptake was due to higher N2 fixation. 相似文献
997.
kouji Tsushima Shingo Ueda Hiroyuki Ohno Norio Ogura Takao Katase Kunio Watanabe 《Water, air, and soil pollution》2006,174(1-4):47-61
This study determined isotopic fractionation of nitrate-nitrogen during denitrification in riparian aquifer sediments by sequential-column experiments at two different water flow rates. The purpose was to discuss the relationships of nitrogen isotopic enrichment factor of denitrification, denitrification rate, and infiltrating condition in sediment. Sandy sediment and groundwater were collected from floodplain in the middle reach of the Tama River where nitrogen isotopic enrichment factor for denitrification had been measured in a result of previous field observation. The denitrification rates and the isotopic enrichment factors of nitrate-nitrogen were estimated at 2.1 mgN dry-kg?1 day?1 and ?32.9‰ during the low water flow condition, and at 3.5 mgN dry-kg?1 day?1 and ?34.1‰ during the high water flow condition. The calculated water flow rates of the present column experiments were 300–400 times higher than that of the field observation. Because of the fast flow rate, nitrate was expected to continuously pass though active denitrifying sites in the small pore spaces of sediment, and nitrate supply to denitrifers by infiltration flow transport greatly exceeded the supply by diffusion. The observed denitrification rates was proportional to Peclet number as the ratio of solute nitrate transport to the diffusion, and apparent nitrogen isotopic enrichment factors during denitrification of our column experiments were lower than those obtained from the field observation. This study showed that denitrification rate and apparent nitrogen isotopic enrichment factor of denitrification in sediment depended on Peclet number. 相似文献
998.
999.
Matsuda-Inoguchi N Shimbo S Nakatsuka H Watanabe T Higashikawa K Ikeda M 《Public health nutrition》2004,7(7):901-909
OBJECTIVE: To identify effects of revision of the Japanese food composition tables from the fourth version to the fifth version on nutrient intake estimation. DESIGN: A database on 783 samples of 24-hour food duplicate portions was re-visited. Nutrients in the duplicate portions were estimated by use of the fourth and fifth versions of the Japanese food composition tables in parallel, together with supplemental use of other databases. The two sets of estimates were subjected to comparison. SETTING: The sample collection was conducted at 31 sites all over Japan. SUBJECTS: The sample donors were 783 women aged 20-78 years. RESULTS: Compared with the estimates by use of the fourth version of the tables, the estimates by the fifth version were substantially higher for intakes of energy, carbohydrate, dietary fibre, vitamin A and niacin, and lower for iron intake. The increase in carbohydrate intake estimates was more evident in older women than in young women, whereas the decrease in the intake estimation of iron and the increase in that of dietary fibre were more marked in young women than in older women. CONCLUSION: The recent revision of food composition tables in Japan induced substantial changes in the estimation of nutrient intakes, i.e. an increase in energy, carbohydrate, dietary fibre, vitamin A and niacin, and a decrease in iron. The extent of the changes varied depending on age. 相似文献
1000.
Pot experiments were conducted to monitor the changes in compositions and δ13C values of soil-trapped CH4 and CO2 in flooded rice soil with and without rice plants or rice straw. Incorporation of rice straw increased the concentration
of CH4 and CO2 accumulated in soil, and the quantities of emitted CH4 to the atmosphere. Rice plants reduced the concentration of soil-trapped CH4 and CO2, and the decreased portion of CH4 was replaced by N2. A significantly negative correlation was found between soil-trapped CH4 and N2. The presence of rice plants increased the δ13C values of CH4. The δ13C values of CH4 tended to increase toward the end of the growing season and were positively correlated with concentration of soil-trapped
CH4. A positive correlation between δ13C values of CH4 and CO2, and between the δ13C values of CH4 and its concentration, were observed. The CH4 in the rice stems was 4–14‰ enriched in 13C relative to soil-trapped CH4. In contrast, CO2 in rice plant stems was 1–9‰ lighter in 13C relative to soil-trapped CO2. These results are discussed in relation to the precursor pools and pathways of methanogenesis.
Received: 11 December 1995 相似文献