排序方式: 共有86条查询结果,搜索用时 15 毫秒
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Makoto Kakinuma Naoko Shibahara Hanako Ikeda Miyuki Maegawa Hideomi Amano 《Fisheries Science》2001,67(2):287-294
SUMMARY: The thermal stress responses of a sterile mutant of the marine alga Ulva pertusa were investigated at 20°C and 30°C. The amounts of the photosynthetic pigments, β-carotene, chlorophylls a and b , lutein, neoxanthin, and violaxanthin, were 1.4–2.4 times higher in the 30°C-cultivated alga than in the 20°C-cultivated alga. The free amino acids, asparagine, aspartic acid, glutamine, glutamic acid, glycine, and serine, were abundant in the 20°C-cultivated alga, and increased 1.9–10.5-fold in response to thermal stress (30°C). Total carbon and nitrogen contents also increased in the 30°C-cultivated alga. Sodium dodecylsulfate-polyacrylamide gel electrophoretic patterns of total proteins extracted from both temperature-treated algae showed the increases of 20, 25, and 90 kDa proteins in the 30°C-cultivated alga. Isozyme assays for 20 enzymes showed a different banding pattern only in the case of glutamate dehydrogenase (GDH). Although it was observed that both temperature-treated algae possessed NAD+ - and NADP+ -specific GDH, the 30°C-cultivated alga had an additional NADP+ -specific GDH (NADP-GDH). These results suggest that NADP-GDH compensates for the thermally induced decreases in nitrogen assimilation efficiency and thereby regulates nitrogen metabolism under conditions of temperature stress. 相似文献
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The mitochondrial genome is believed to be maternally inherited in many eukaryotes. Sperm-derived paternal mitochondria enter the oocyte cytoplasm upon fertilization and then normally disappear during early embryogenesis. However, the mechanism responsible for this clearance has been unknown. Here, we show that autophagy, which delivers cytosolic components to lysosomes for degradation, is required for the elimination of paternal mitochondria in Caenorhabditis elegans. Immediately after fertilization, sperm-derived components trigger the localized induction of autophagy around sperm mitochondria. Autophagosomes engulf paternal mitochondria, resulting in their lysosomal degradation during early embryogenesis. In autophagy-defective zygotes, paternal mitochondria and their genome remain even in the first larval stage. Thus, fertilization-triggered autophagy is required for selective degradation of paternal mitochondria and thereby maternal inheritance of mitochondrial DNA. 相似文献
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Tanaka T Mine C Inoue K Matsuda M Kouno I 《Journal of agricultural and food chemistry》2002,50(7):2142-2148
Oxidation products of (-)-epicatechin and (-)-epigallocatechin by treatment with homogenates of 62 plants belonging to 49 families were compared. Forty-six plants were capable of synthesizing theaflavin, a black tea pigment, regardless of whether they contained catechins. Loquat, Japanese pear, and blueberry had activities higher than that of fresh tea leaves after 5 h of treatment; furthermore, these plants oxidized theaflavin to theanaphthoquinone. An additional new metabolite, dehydrotheasinensin, was generated on treatment with fresh tea leaves, eggplant, and unripened Japanese orange. Evidence for the oxidation of epigallocatechin and theaflavin by electron transfer to epicatechin quinone was demonstrated in a time course study using bananas and trapping the quinone intermediates as glutathione conjugates. 相似文献
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Hirohito OGAWA Miyuki OHNUMA David SQUARRE Aaron Simanyengwe MWEENE Takayuki EZAKI Daisuke FUJIKURA Naomi OHNISHI Yuka THOMAS Bernard Mudenda HANG’OMBE Hideaki HIGASHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(8):993-995
To follow-up anthrax in Zambia since the outbreak in 2011, we have collected samples from the environment and the carcasses of anthrax-suspected animals, and have tried to isolate Bacillus anthracis. In the process of identification of B. anthracis, we collected two isolates, of which colonies were similar to B. anthracis; however, from the results of identification using the molecular-based methods, two isolates were genetically related to the highly pathogenic B. cereus, of which clinical manifestation is severe and fatal (e.g., pneumonia). In this study, we showed the existence of bacteria suspected to be highly pathogenic B. cereus in Zambia, indicating the possibility of an outbreak caused by highly pathogenic B. cereus. 相似文献
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Miyuki MORI Takeshi HAYASHI Yoshihiro ISOZAKI Naoki TAKENOUCHI Miki SAKATANI 《The Journal of reproduction and development》2015,61(5):423-429
In this study, the effect of heat shock on frozen-thawed blastocysts was evaluated using in
vitro-produced (IVP) bovine embryos. In experiment 1, the effects of 6 h of heat shock at 41.0 C on
fresh blastocysts were evaluated. HSPA1A expression as a reflection of stress was increased
by heat shock (P < 0.05), but the expressions of the quality markers IFNT and
POU5F1 were not affected. In experiment 2, frozen-thawed blastocysts were incubated at 38.5
C for 6 h (cryo-con) or exposed to heat shock at 41.0 C for 6 h (cryo-HS). Then, blastocysts were cultured at
38.5 C until 48 h after thawing (both conditions). Cryo-HS blastocysts exhibited a decreased recovery rate:
HSPA1A expression was dramatically increased compared with that in fresh or cryo-con
blastocysts at 6 h, and IFNT expression was decreased compared with that in cryo-con
blastocysts at 6 h (both P < 0.05). Cryo-con blastocysts at 6 h also exhibited higher
HSPA1A expression than fresh blastocysts (P < 0.05). At 48 h after thawing, the number
of hatched blastocysts and blastocyst diameter were lower in cryo-HS blastocysts (P < 0.05). Cryo-con
blastocysts showed lower POU5F1 levels at 48 h than fresh, cryo-con or cryo-HS blastocysts at
6 h (P < 0.05), but their POU5F1 levels were not different from those of cryo-HS
blastocysts at 48 h. These results indicated that application of heat shock to frozen-thawed blastocysts was
highly damaging. The increase in damage by the interaction of freezing-thawing and heat shock might be one
reason for the low conception rate in frozen-thawed embryo transfer in summer. 相似文献
57.
Photosynthetic activities of seedlings of Zostera marina were successively measured using a gas volumeter for 6 days at seven light (0–400 μmol photons/m2 per s) and 11 water temperature conditions (5–35°C). The seedlings were collected from mature plants (Ise Bay, central Japan),
and stored and cultured in incubators accurately controlled at each test temperature. The maximum gross photosynthesis (P
maxg) was recorded at an optimal water temperature of 29°C after 0 days. After 6 days, P
maxg appeared at 25°C and most plants cultured at 29–30°C bleached and withered after the drastic increase of light compensation
point (I
c). On the contrary, at 5–28°C, the photosynthetic activities either changed little (5–25°C) or recovered after a temporal
reduction (26–28°C); seedlings survived and looked healthy after being cultured for 6 days. The recovery was thought to be
an acclimation to tolerate higher water temperature. As a result, the critical upper water temperature for Z. marina seedlings was proposed as 28°C. The temperature was consistent with the previously reported maximum water temperature in
habitats around the southern boundary of Z. marina in the northern hemisphere. 相似文献
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Peroxidases are the major candidate enzymes involved in dehydrogenative polymerization of monolignols. Peroxidases have the signal sequence at their N-terminus and this suggests that they are transported to extracellular spaces or developing cell walls. In this study, we focused on an anionic peroxidase isozyme encoded by prxA3a, which seems to be related to lignification. To investigate the localization of peroxidase in differentiating xylem cells of poplar (Populus sieboldii × Populus grandidentata), anti-PRX3 antibody was raised against the anionic peroxidase. Western blotting and peroxidase activity inhibition assay showed specificity of the antibody. Labeling by anti-PRX3 antibody was localized in vessels and fibers during the secondary wall formation and was observed along the plasma membrane beside the microtubules. The labeling was not seen in the cell wall, where localization of peroxidases was expected during lignification. The peroxidase isozyme, which is suggested to be involved in monolignol polymerization, is localized on the plasma membrane and its localization might be regulated by microtubules. 相似文献
60.
Miyuki Fukuda Yasuko Tsujino Takane Fujimori Ko Wakabayashi Peter Bger 《Pesticide biochemistry and physiology》2004,80(3):143-150
Phytotoxic activity of several middle-chain fatty acids, especially pelargonic acid (C9 acid) was investigated. C9–C11 acids caused strong non-selective damage to plants such as crabgrass, cucumber, velvetleaf, and tobacco, while C6 and C14 fatty acids had almost no activity. Middle-chain fatty acids caused a strong and rapid electrolyte leakage. They reached highest conductivity in 3 h in the case of cucumber cotyledons. Middle-chain fatty acids caused a decrease of the amount of polar lipids, particularly MGDG and PG, and chlorophylls. They also caused an increase of free fatty acids in 24 h after treatment. These results suggested that middle-chain fatty acids caused severe damage to cell membranes and thylakoid membranes of treated leaves. C6 volatile compounds such as cis-3-hexenal, trans-2-hexenal, and cis-3-hexenol were generated in less than 1 h after spraying pelargonic acid to tobacco leaves. The application of pelargonic acid was thought to be the trigger for linolenic acid degradation in the thylakoid membranes. 相似文献