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YuHua Kong Mirai Watanabe Hirohiko Nagano Keiji Watanabe Miwa Yashima 《Soil Science and Plant Nutrition》2013,59(5):790-799
Land-use type and nitrogen (N) addition strongly affect nitrous oxide (N2O) and carbon dioxide (CO2) production, but the impacts of their interaction and the controlling factors remain unclear. The aim of this study was to evaluate the effect of both factors simultaneously on N2O and CO2 production and associated soil chemical and biological properties. Surface soils (0–10 cm) from three adjacent lands (apple orchard, grassland and deciduous forest) in central Japan were selected and incubated aerobically for 12 weeks with addition of 0, 30 or 150 kg N ha–1 yr–1. Land-use type had a significant (p < 0.001) impact on the cumulative N2O and CO2 production. Soils from the apple orchard had higher N2O and CO2 production potentials than those from the grassland and forest soils. Soil net N mineralization rate had a positive correlation with both soil N2O and CO2 production rates. Furthermore, the N2O production rate was positively correlated with the CO2 production rate. In the soils with no N addition, the dominant soil properties influencing N2O production were found to be the ammonium-N content and the ratio of soil microbial biomass carbon to nitrogen (MBC/MBN), while those for CO2 production were the content of nitrate-N and soluble organic carbon. N2O production increased with the increase in added N doses for the three land-use types and depended on the status of the initial soil available N. The effect of N addition on CO2 production varied with land use type; with the increase of N addition doses, it decreased for the apple orchard and forest soils but increased for the grassland soils. This difference might be due to the differences in microbial flora as indicated by the MBC/MBN ratio. Soil N mineralization was the major process controlling N2O and CO2 production in the examined soils under aerobic incubation conditions. 相似文献
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Yuichi Ozaki Hideki Tanaka Hirohiko Kagawa Hiromi Ohta Shinji Adachi Kohei Yamauchi 《Fisheries Science》2006,72(1):13-19
ABSTRACT: The fine structure of the alimentary canal in preleptocephali produced by artificially matured Japanese eel was examined. At 1 day posthatch (dph), the alimentary canal was found only above the dorsal side of the yolk mass, and the epithelium was composed of a single layer of epithelial cells. By 5 dph, the alimentary canal was divided into three segments based on the structure of the epithelial cells: foregut, midgut and hindgut, corresponding to the future esophagus, intestine and rectum, respectively. After 7 dph, the epithelium in the foregut was surrounded by a circular muscle layer, suggesting a role in the transportation of food materials. The epithelial cells of the midgut exhibited well-developed membranous structures, which are deduced to be invaginations of the cytoplasmic membrane. Pinocytotic invaginations and vacuoles were observed in the epithelial cells of the hindgut; this observation suggests that this region is involved in the uptake of food. Significant changes in morphological features of the epithelial cells in each segment were observed until 7 dph; however, these were not evident between 7 dph and 13 dph. Consequently, the differentiation of the alimentary canal was completed by 7 dph, and preleptocephalus had developed the ability to absorb food by 7 dph. 相似文献
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Nobuyoshi Mikami Jun Yoshimura Hideo Kaneko Hirohiko Yamada Junshi Miyamoto 《Pest management science》1985,16(1):33-45
Upon single oral administration to rats, the mono-, di- and tri-glucose conjugates of [14C]-3-phenoxybenzyl alcohol ( I ) or the mono-glucose conjugate of [14C]-3-phenoxybenzoic acid ( II ) were rapidly hydrolysed and extensively eliminated in the urine mostly as the sulphate conjugate of 3-(4-hydroxyphenoxy)benzoic acid ( X ). The faecal elimination was a minor route, whereas the biliary excretion was about 42% of the dose and the glucuronide conjugates of I , II and X were common major metabolites. The biliary glucuronides were cleaved in the small intestine to the respective aglycones, which were reabsorbed, metabolised further, and excreted in the urine as the sulphate conjugate of X . Although small amounts of the mono-, di-and tri-glucosides were found in the 0.5-h blood and liver samples following oral administration of the tri-glucoside of I , they were not detected in the urine, bile or faeces. Similarly the sulphate conjugate was one of the major urinary metabolites of germ-free rats, dosed with the 14C-glucosides via the oral or the intraperitoneal route, although they were excreted unchanged in certain amounts in the urine and faeces. The glucose conjugates were cleaved in vitro by gut microflora and in various rat tissues, including blood, liver, small intestine and small intestinal mucosa. The tissue enzymes showed a different substrate specificity in hydrolysis of the glucosides. However, they were not cleaved in gastric juice, bile, pancreatic juice or urine. 相似文献
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Nobuyoshi Mikami Noriko Wakabayashi Hirohiko Yamada Junshi Miyamoto 《Pest management science》1984,15(6):531-542
The metabolism of 3-phenoxybenzoic acid, a common plant metabolite of deltamethrin, cypermethrin and fenvalerate, has been studied in abscised leaves of cabbage, cotton, cucumber, kidney bean and tomato plants. The [14C]-acid was readily converted into more polar conjugates by esterification with glucose, 6-O-malonylglucose, gentiobiose, cellobiose, glucosylxylose and two types of triglucose with different isomerism. Other metabolites identified were the glucosyl ether of 3-(4-hydroxyphenoxy)benzoic acid, and a 3-(2-hydroxyphenoxy)benzoic acid derivative with a total of two molar equivalents of glucose linked to the carboxyl and phenolic -OH groups. The conjugation pathways were somewhat plant-specific. The glucosylxylose ester was found only in cotton, and the cellobiose and triglucose esters were found only in tomato. All of the conjugates except the glucose and glucosylxylose esters were plant metabolites that had not been identified previously. Furthermore, this is the first report to show the presence of cellobiose and triglucose conjugates in plants. However, neither of the acetyl derivatives of the [14C]-triglucoside was identical with the synthetic deca-acetyl derivative of [1→6]-triglucoside. 相似文献
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Naohiro Takahashi Nobuyoshi Mikami Hirohiko Yamada Junshi Miyamoto 《Pest management science》1985,16(2):113-118
The hydrolysis of [14C] fenpropathrin ( I ) [(RS)-α-cyano-3-phenoxybenzyl 2,2,3,3-tetramethylcyclopropanecarboxylate] was studied in buffer solutions at pH 1.9–10.4, and in natural river and sea water at 25, 40, 55 and 65°C under laboratory conditions. The hydrolysis of I proceeded predominantly through neutral (pH independent) and base-catalysed processes in the regions below pH 3.9 and above pH 7.0, respectively, whereas both reactions occurred between pH 3.9 and 7.0. The rates of hydrolysis of I in buffer solutions were similar to those in one sample of river and one sample of sea water. If this obtains generally, it may be expected that the half-life of I in natural waters, normally within the range pH 5–9, will range from 1.54 to 1080 days at 40°C, 11.3 to 8520 days at 25°C and, by extrapolation of the data obtained in buffer solutions, 106 to 83 000 days at 10°C. The rate constants for hydrolysis of I in aqueous media can be expressed by: Where log kN = 9.60–(5.56 × 103 T?1) and log kB = 7.32–(2.56 × 103 T?1). The calculated rate constants were in good accord with the observed values in buffer solutions. Cleavage of the ester linkage was more rapid than hydration of the cyano group at any pH and temperature tested. 相似文献
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Kamemori N Takeuchi T Sugiyama A Miyabayashi M Kitagawa H Shimizu H Ando K Harada E 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(3):313-315
The transportation of intravenously administered bovine lactoferrin (bLF) into the cerebrospinal fluid (CSF) was immunohistochemically investigated in adult rats. Administered bLF was detected in the vesicular membranes of endothelial cells in cerebral blood vessels 10 min after the infusion. Numerous immunoreactive small vesicles were also detected at the ependymal cells in the choroid plexus. Moreover, the bLF concentration in the CSF was significantly increased at 1-2 hr after the intravenous infusion of bLF (10 or 30 mg/kg). These findings clearly demonstrate that LF is possibly transported into the brain matter even in adult animals. 相似文献
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Tanaka Hiroshige Kodama Taketoshi Suzuki Nobuaki Mochizuki Yosuke Ashida Hiroshi Sato Takuya Takeshima Hirohiko Nohara Kenji 《Fisheries Science》2020,86(6):1019-1028
Fisheries Science - The distribution and early growth of juvenile Pacific bluefin tuna (PBF) Thunnus orientalis were studied based on trawl surveys conducted around Sado Island, eastern Sea of... 相似文献
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Kohei OHTA Sonoko YAMAGUCHI Akihiko YAMAGUCHI Koichi OKUZAWA Koichiro GEN Hirohiko KAGAWA Michiya MATSUYAMA 《Fisheries Science》2002,68(3):680-687
ABSTRACT: The red seabream Pagrus major is a useful experimental fish for studying the endocrine control of oogenesis in teleosts. This study investigated the steroidogenic pathway for estradiol-17β (E2) biosynthesis in the ovarian follicles of red seabream. Intact follicles were isolated during vitellogenesis and incubated in vitro with different radiolabeled steroid precursors. When 17-hydroxyprogesterone (17-P), dehydroepiandrosterone (DHEA), or androstenedione (AD) were used as precursors, both testosterone (T) and estrone (E1) were synthesized by follicles, leading to estradiol-17β (E2) production. Serum steroid levels measured by enzyme-linked immunosorbent assay showed that T, E1, and E2 were present in the circulation at levels ranging from 1 ng/mL to 2 ng/mL throughout the day during the spawning season. In vitro conversion of E1 into E2, however, was 15.8-fold greater than T conversion into E2, suggesting that E2 is synthesized mainly via E1 rather than T. The results showed that E2 was synthesized from pregnenolone via 17-hydroxypregnenolone, DHEA, AD, and E1. Thus, the study demonstrated the complete steroidogenic E2 synthesis pathway in the ovarian follicles of red seabream, and revealed that E1 is the major precursor of E2. 相似文献