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141.
142.
Kawakubo M Ito Y Okimura Y Kobayashi M Sakura K Kasama S Fukuda MN Fukuda M Katsuyama T Nakayama J 《Science (New York, N.Y.)》2004,305(5686):1003-1006
Helicobacter pylori infects the stomachs of nearly a half the human population, yet most infected individuals remain asymptomatic, which suggests that there is a host defense against this bacterium. Because H. pylori is rarely found in deeper portions of the gastric mucosa, where O-glycans are expressed that have terminal alpha1,4-linked N-acetylglucosamine, we tested whether these O-glycans might affect H. pylori growth. Here, we report that these O-glycans have antimicrobial activity against H. pylori, inhibiting its biosynthesis of cholesteryl-alpha-D-glucopyranoside, a major cell wall component. Thus, the unique O-glycans in gastric mucin appeared to function as a natural antibiotic, protecting the host from H. pylori infection. 相似文献
143.
Sato H Hirata N Koketsu K Okaya D Abe S Kobayashi R Matsubara M Iwasaki T Ito T Ikawa T Kawanaka T Kasahara K Harder S 《Science (New York, N.Y.)》2005,309(5733):462-464
Devastating earthquakes occur on a megathrust fault that underlies the Tokyo metropolitan region. We identify this fault with use of deep seismic reflection profiling to be the upper surface of the Philippine Sea plate. The depth to the top of this plate, 4 to 26 kilometers, is much shallower than previous estimates based on the distribution of seismicity. This shallower plate geometry changes the location of maximum finite slip of the 1923 Kanto earthquake and will affect estimations of strong ground motion for seismic hazards analysis within the Tokyo region. 相似文献
144.
Tyrosinase, trypsin, and tryptase are known to play important roles in melanin production of human skin. This paper describes the study of the inhibitory effect of Balanophora fungosa on melanin. The 50% EtOH extract obtained from B. fungosa indicated an inhibitory effect on mushroom tyrosinase activity with an IC(50) value of 15 μg/mL. Bioassay-guided fractionation of the active extract resulted in the isolation of four known compounds. Their structures were identified as 1-O-(E)-caffeoyl-3-O-galloyl-4,6-(S)-HHDP-β-d-glucopyranose (1), 1-O-(E)-caffeoyl-3,4,6-tri-O-galloyl-β-d-glucopyranose (2), caffeoyl-β-d-glucopyranose (3), and abietin (4) on the basis of spectroscopic analyses and comparison of their spectral data with those in the literature. Compounds 1 and 2 prevented pigmentation of melanin in a three-dimensional cultured human skin model. Furthermore, compounds 1 and 2 indicated inhibitory activities against trypsin and tryptase. 相似文献
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146.
Hirohiko Nagano Soh Sugihara Miwa Matsushima Susumu Okitsu Valentina E. Prikhodko Elena Manakhova 《Soil Science and Plant Nutrition》2013,59(2):238-244
The effects of different land-use histories on contents of soil carbon (C) and nitrogen (N) and fluxes of greenhouse gases [carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)] measured using the closed chamber method were investigated in the Arkaim museum reserve located in the South Ural of Russia. A natural forest site (NF) and two grassland sites that had different land-use histories (CL: cropland until 1991; PST: pasture until 1991; both sites have been fallow for 18 years) were selected for soil sampling and gas flux measurements. The vegetation in NF was mainly Betula pendula Roth. with steppe cherry and grassy cover. Perennial grasses (Stipa spp., Festuca spp. and others) have been planted in CL and PST since 1991 to establish reserve mode, and the projective cover of these plants were?>?90% in both sites in 2009. Soil samples were taken from the A horizon in the three sites, and additionally samples of the O horizon were taken from NF. The contents of soil C and N [total C, total N, soluble organic C, soluble N and microbial biomass C (MBC)] in the O horizon of NF were the largest among all investigated soils (p?0.05). Additionally, the total C, total N and MBC in PST were significantly larger than in CL (p?0.05). Positive CO2 fluxes (i.e., CO2 efflux) in all three investigated sites were observed. The CO2 efflux in NF was significantly larger than in CL and PST (129, 30 and 25?mg C m?2 hour?1, respectively, p?0.05), although there was no significant difference in values of CO2 efflux between CL and PST. There were no significant differences in the fluxes of CH4 and N2O among NF, CL and PST (p?>?0.05). Our current research indicated that, in soils of the Eurasian steppe zone of Russia, total C, total N and MBC were affected not only by current land-use (i.e., fallow grassland vs. natural forest) but also by past (until 18 years ago) land-use. 相似文献
147.
Kohei Yamashita Hiroki Honjo Mizuhiko Nishida Makoto Kimura Susumu Asakawa 《Soil Science and Plant Nutrition》2013,59(4):512-519
AbstractPotassium (K) in microbial cells, microbial biomass K, in soil has been recently recognized as a K pool for plant growth. We determined soil microbial biomass K in paddy fields to reveal its importance as a K pool in paddy field soil for the first time. Microbial biomass K ranged from 5 to 21 mg K kg?1 in the soil samples periodically collected from a paddy field and the value corresponded to 41% of the exchangeable K on average. Both microbial biomass K and exchangeable K increased conspicuously due to the long-term application of livestock manure compost or rice straw compost. Biomass K was higher than exchangeable K under K-deficient conditions in the long-term experimental plots without K application. The present study revealed that the microbial biomass contained considerable amounts of K in paddy field soil, indicating the need for evaluation of the microbial biomass K as a source and a stock of K in soil that has been overlooked. 相似文献
148.
Abstract Protease-active extracts were prepared from 2 rice-rhizosphere and non-rhizosphere soil samples 3 proteolytic isolates from the soil samples which were taken from water logged paddy fields (Gray Lowland Soils) under double cropping of rice and wheat that had been treated with chemical fertilizer (CF) or organic manure (OM). The activities were assayed and characterized using an artificial substrate, benzyloxycarbonyl-L-phenylalanyl-L-tyrosyl-L-leucine (ZFTL). The protease-active extracts from the rhizosphere and non-rhizosphere of the CF and OM soils (abbreviated as CFR, CFN, OMR, and OMN) showed an optimum pH between 7 and 8. The extracts hydrolyzed ZFTL to Tyr-Leu and Leu; generally, Tyr-Leu was the main reaction product. Activities of all the samples were inhibited by EDTA and p-chloromercuribenzoic acid (PCMB) but not by pepstatin and phenylmethanesulfonyl fluoride (PMSF). These results indicate that the main components of the ZFTL-hydrolases in CFR, CFN, 0MR, and OMN were essentially similar. Optimum pH for the activity of the protease extracted from a Gram negative rod (MNB003)., two actinomycetous isolates (MNA014., MRA017) was about 8, 8, and 8.5, respectively. Extract from the culture of MNB003 hydrolyzed ZFTL to Tyr-Leu., Leu,., the protease activity was inhibited by EDTA., PCMB. Protease activities of the extracts from cultures of the two actinomycetes were inhibited by EDTA but not by PCMB. The extract from culture of MNA014 produced mainly Tyr-Leu from ZFTL while MRA017 produced Leu. Characteristics of the protease activity from cultures of MNB003., MNA014 were similar to those of the enzyme extracted from a paddy field soil under single cropping (Takeuchi., Hayano 1994: Soil Sci. Plant Nutr., 40, 691-695) and from an Andosol under tomato cultivation (Hayano et al. 1987: Biol. Fertil. Soils, 4, 179-183), respectively. 相似文献
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150.
Effect of temperature,hypoxia and disinfection with ozonated seawater during somitogenesis on muscular development of the trunk in larval seven‐band grouper,Epinephelus septemfasciatus (Thunberg)
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Susumu Uji Tohru Suzuki Takashi Iwasaki Kazuhisa Teruya Keiichi Hirasawa Makoto Shirakashi Shizumasa Onoue Yoichi Yamashita Masaharu Tsuji Yasushi Tsuchihashi Koichi Okuzawa 《Aquaculture Research》2015,46(11):2698-2706
The cause of abnormal musculature on both sides of the same myotome in artificially cultured seven‐band grouper Epinephelus septemfasciatus (Thunberg) larvae remains unclear. We evaluated the effect of three factors: changes in temperature (between 22 and 24°C), disinfection with ozonated seawater (0.3 mg TROs L?1, 1 min), and hypoxia (22 or 14% saturation) during the early (20 h post‐fertilization, hpf) and mid‐ (24 hpf) somite stages on trunk muscular development in larval seven‐band grouper. The thermal regimes and disinfection with ozonated seawater had no effect on muscle development (P > 0.05, G‐test). In contrast, exposure to hypoxia during both the early and mid‐somite stages increased the incidence of abnormal musculature in the trunk (P < 0.01, G‐test). These larvae had abnormal musculature on both sides of the trunk. In addition, the number of abnormal myotomes differed among these larvae. Exposure in the early and mid‐somite stages resulted in the highest frequency of abnormalities in the 11th and 13th myotome respectively. Our results suggest that hypoxia during somitogenesis can lead to abnormal muscle development in the trunk of artificially cultured seven‐band grouper larva. 相似文献