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21.
Nakagawa I Amano A Mizushima N Yamamoto A Yamaguchi H Kamimoto T Nara A Funao J Nakata M Tsuda K Hamada S Yoshimori T 《Science (New York, N.Y.)》2004,306(5698):1037-1040
We found that the autophagic machinery could effectively eliminate pathogenic group A Streptococcus (GAS) within nonphagocytic cells. After escaping from endosomes into the cytoplasm, GAS became enveloped by autophagosome-like compartments and were killed upon fusion of these compartments with lysosomes. In autophagy-deficient Atg5-/- cells, GAS survived, multiplied, and were released from the cells. Thus, the autophagic machinery can act as an innate defense system against invading pathogens. 相似文献
22.
Erik A. Hobbie Lidia S. WatrudSharon Maggard Tamotsu ShiroyamaPaul T. Rygiewicz 《Soil biology & biochemistry》2003,35(2):303-311
Soil fungi are integral to decomposition in forests and other habitats, yet identifying probable functional roles of different taxa is problematic. Here, we compared carbohydrate assimilation patterns derived from stable isotope analyses on cultures with patterns of metabolic activity measured on Biolog® SF-P plates for 12 taxa of soil- and litter-inhabiting saprotrophic fungi isolated from Douglas-fir (Pseudotsuga menziesii) ecosystems. To determine the relative assimilation of carbon from malt extract versus sucrose by 13C stable isotope analyses, we cultured fungi with malt extract (consisting primarily of glucose and maltose) plus either C3- or C4-derived sucrose as carbon sources. Rhodotorula graminis and F. oxysporum assimilated the highest proportion of sucrose, a Mortierella isolate and an unidentified sterile isolate (FPC 341) assimilated the lowest proportion of sucrose, and remaining cultures assimilated similar and intermediate proportions of sucrose. On Biolog plates, low metabolic activity of Mortierella and FPC 341 on sucrose and R. graminis and F. oxysporum on maltose were qualitatively consistent with isotopic results. Assimilation of sucrose calculated isotopically was correlated with the ratio of sucrose: maltose activity calculated from Biolog assays (r2=0.45, P=0.0145, n=12). Metabolic activity on Biolog plates for six other common soil carbohydrates were also determined: glucose, fructose, galactose, cellobiose, lactose, and glycogen. Metabolic activity was greatest overall on maltose and glucose and lowest on fructose. Two of the isolates (Aspergillus flavus and F. oxysporum) had higher metabolic activity on the glucose-containing disaccharide cellobiose than on glucose, strongly suggesting preferential uptake of cellobiose compared to glucose and suggesting the potential ability to use cellulose. The high metabolic activity of these cultures on galactose, a primary constituent of hemicellulose, also suggested cellulolytic capabilities. Our results indicated that stable isotope studies and Biolog assays may provide complementary information to characterize metabolic potential of fungi in forest litter and soil. 相似文献
23.
Joseph C. Greene William E. Miller Tamotsu Shiroyama Thomas E. Maloney 《Water, air, and soil pollution》1975,4(3-4):415-434
The most characteristic water quality problem of the Snake River Basin is the excessive aquatic growth and thick blooms of algae. The cause of these aquatic growths is related to the high concentrations of basic nutrients — nitrogen and phosphorus — in the Snake system. Industrial wastes, natural phosphate levels, irrigation return flows, municipal wastes, and the decay of aquatic biota all contribute to the nutrient balance which stimulates aquatic growths. Algal assays were conducted on waters of eighteen Snake River and tributary sites to: (1) determine if algal growth was consistent with results predicted from review of chemical analysis for orthophosphorus and total soluble inorganic N; (2) determine if algal yields were limited by P, N, or some other nutrient essential to algal growth; and (3) predict the effects of N or P additions on algal productivity. 相似文献
24.
Lidia S. Watrud Santosh Misra Leshitew Gedamu Tamotsu Shiroyama Sharon Maggard George Di Giovanni 《Water, air, and soil pollution》2006,176(1-4):329-349
The objectives of these studies were two-fold: (1) to determine efficacy of low and high expression hMT gene constructs by assessing accumulation of Cu in shoots of parental and transgenic plants of alfalfa (Medicago varia L.) exposed to different concentrations of CuSO4 by addition of CuSO4 solutions to soil and (2) to identify potential unintended effects of the genetic engineering on root and shoot biomass, shoot nutrient content, arbuscular mycorrhizal infection and on the metabolic functions of microbial communities in the rhizosphere. In the absence of exogenous CuSO4 additions to soil shoot biomass and the macronutrient (C, P, K, Ca, Mg and N) content of plants expressing hMT were not significantly different from the parental control. In the 0.5 mM and 1.0 mM CuSO4 treatments transgenic plants expressing the commonly used transgenic β-glucuronidase (GUS) marker had significantly higher Fe content than the parental genotype. Significant differences were observed in the carbon substrate utilization patterns of rhizosphere microbial communities among the transgenic plants; no significant differences were observed in the percent mycorrhizal infection of parental and transgenic plants. Shoot biomass increased significantly in all genotypes treated with 0.5 mM CuSO4 and decreased in all genotypes at CuSO4 concentrations of 1.5 mM and 2.0 mM. Root dry weights decreased significantly in all genotypes at concentrations of 1.0 mM, 1.5 mM and 2.0 mM CuSO4. The largest decreases in root dry weight were observed in hMT genotypes grown in soil treated with 1.5 and 2.0 mM CuSO4. In plants treated with 1.5 mM CuSO4, shoots of transgenic plants expressing the hMT gene accumulated nominally, but not statistically significantly higher levels of Cu in shoot tissue. Our results were surprising with regard to lack of sufficient efficacy of the current hMT constructs for significant accumulation of Cu from soil treated with CuSO4. However, our results suggest the utility of applying adverse levels of CuSO4 or other environmental stressors to identify potential unintended effects of genetic engineering that may not be apparent under typically more optimal plant growth test conditions. 相似文献
25.
Nguyen Toan Thang Tran Van Do Tamotsu Sato Nguyen Trong Binh Osamu Kozan Ngo Van Cam 《Small-Scale Forestry》2016,15(2):229-239
Chestnuts have historical importance as a food source worldwide. Planting of chestnuts has focused on a few species, including Castanea dentata, Castanea sativa, Castanea mollissima, and Castanea crenata, although others species are also edible. Castanea species are members of the beech family (Fagaceae) and are native to tropical and temperate areas. In this study, the yield and nut quality of Castanopsis piriformis in natural forests of the Central Highlands of Vietnam were investigated to provide evidence that C. piriformis is worth growing as a food species. Data were collected from 12 plots of 50 m × 50 m size located in four altitude zones. Nuts were collected from three to five chestnut trees in each plot judged to be of typical sized based on diameter at breast height and crown diameter. Average dry yield of nuts was found to be elevation-dependent, being highest at 500–1000 m (1152 kg/ha/year), decreasing to 815 kg/ha/year below 500 m, and to 770 kg/ha/year at 1000–1500 m. The lowest yield was observed at above 1500 m (252 kg/ha/year). Protein and lipid contents in the kernels of C. piriformis chestnut were 4.4 and 0.1 %, respectively. Glucose accounted for 73.1 % and was significantly higher than that of commercially grown Castanopsis boisii chestnuts in Northern Vietnam. With the current price of 0.6 US$/kg nuts, collecting nuts growing in natural forest can bring at least 480 US$/ha/year to local people. These results indicate the possibility of growing and consuming C. piriformis chestnut as a crop to decrease poverty. However, governmental support is required for the sustainable development of C. piriformis. 相似文献
26.
Hiroka Ito Satoshi Ito Tamotsu Matsui Tomomi Marutani 《Journal of Forest Research》2006,11(6):405-417
We investigated habitat segregation and patterns of species diversity of trees in relation to variations in fluvial and geomorphic
disturbances (erosion or sedimentation) along a longitudinal stream gradient from V-shaped valley to alluvial fan and between
valley and adjacent hill slopes in a warm-temperate mountainous riparian forest in Kyushu, southwestern Japan. We longitudinally
divided the riparian area into four geomorphic zones: V-shaped valley (VV-zone), upper fan (UF-zone), middle fan (MF-zone),
and lower fan (LF-zone). We surveyed the distribution of tree species (diameter at breast height ≥3 cm) in the four riparian
zones and in additional plots on hill slopes (SL-zone) representing the broader, nonriparian forest matrix. Detrended correspondence
analysis ordination demonstrated variations in species composition along the longitudinal stream gradient. Species guild analysis
based on the detection of the species preferred zone by a bootstrap method revealed a guild structure corresponding to each
geomorphic zone. The four riparian zones were differentiated from the SL-zone by having a low proportion of SL-guild species
and a high proportion of infrequent species that were characterized by deciduous leaf habit. The LF-zone was the most differentiated
and was characterized by low tree density and specialist species established on the flat and unstable soil surface created
by frequent deposition of sediment. The UF- and MF-zones were characterized by a high tree density and species richness (particularly
of infrequent species) established on the stable ground surface of a high alluvial terrace. Microsite heterogeneity produced
by channel formation may also maintain a high species diversity in the riparian zones. 相似文献
27.
Ogawa M Yoshimori T Suzuki T Sagara H Mizushima N Sasakawa C 《Science (New York, N.Y.)》2005,307(5710):727-731
The degradation of undesirable cellular components or organelles, including invading microbes, by autophagy is crucial for cell survival. Here, Shigella, an invasive bacteria, was found to be able to escape autophagy by secreting IcsB by means of the type III secretion system. Mutant bacteria lacking IcsB were trapped by autophagy during multiplication within the host cells. IcsB did not directly inhibit autophagy. Rather, Shigella VirG, a protein required for intracellular actin-based motility, induced autophagy by binding to the autophagy protein, Atg5. In nonmutant Shigella, this binding is competitively inhibited by IcsB binding to VirG. 相似文献
28.
Tadahiko Kuriyama Sayaka Fusazaki Tadaaki Satou Tamotsu Nikaido 《Pesticide biochemistry and physiology》2005,81(3):176-187
The present study was undertaken to identify noncompetitive γ-aminobutyric acid receptor (GABAR) antagonists that are effective in nematodes, as well as to examine the hypothesis that the noncompetitive antagonism of the GABAR underlies the nematocidal activity of quassinoids against free-living nematodes of the Diplogastridae family. First, 14 known GABAR antagonists were screened for the effectiveness of their nematocidal activity in Diplogastridae. As a result, 3-isopropyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane 1-sulfides (3-isopropyl-BPTs) were found to have high nematocidal activities, and 4-cyclohexyl-3-isopropyl-BPT (23) and 3-isopropyl-4-(2-propenyl)-BPT (27) were the two most potent analogues; these compounds are equipotent to samaderine B and more potent than the anthelmintic abamectin. 23-resistant nematodes, selected by challenge with 23, showed cross-resistance to samaderine B. 23 (10 μM) reduced [3H]23 binding to nematode membranes by 30.4%. Samaderine B (10 μM) resulted in a similar level of the inhibition, but had neither additive nor synergistic effects on the 23 inhibition of [3H]23 binding. These findings suggest that samaderine B shares a common binding site with the GABAR antagonist 23 in Diplogastridae. The results of comparative molecular field analysis, a method of three-dimensional quantitative structure-activity relationship analysis, supported this conclusion. 相似文献
29.
Yasutomo Hori Masayuki Iguchi Yasuhiro Heishima Yohei Yamashita Kensuke Nakamura Atsushi Hirakawa Akihito Kitade Toshiki Ibaragi Michio Katagi Tamotsu Sawada Masashi Yuki Nobuyuki Kanno Haruki Inaba Noriko Isayama Hideyuki Onodera Naoki Iwasa Mikio Kino Mikihiro Narukawa Syuhei Uchida 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2018,32(3):922-929
30.
Yoshihisa Ozoe Miki Akamatsu Taizo Higata Izumi Ikeda Kazuo Mochida Kazuo Koike Taichi Ohmoto Tamotsu Nikaido 《Pest management science》1999,55(6):665-666
Different structural features govern the interaction of picrodendrins and related terpenoids with rat and with housefly GABA receptors. This supports previous studies which suggest that there are significant differences between the structures of the binding sites in these two receptors. 相似文献