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991.
Elhussiny Mohamed Z. Tran Phuong V. Wang Ying Ouchi Yoshimitsu Haraguchi Shogo Gilbert Elizabeth R. Cline Mark A. Bungo Takashi Furuse Mitsuhiro Chowdhury Vishwajit S. 《Amino acids》2023,55(2):183-192
Amino Acids - Brain amino acid metabolism has been reported to regulate body temperature, feeding behavior and stress response. Central injection of taurine induced hypothermic and anorexigenic... 相似文献
992.
Hiroshi Mano Masaharu Yamamoto Juan Carlos Araya Kiyoshi Kato Mitsuhiro Tsutsui Tatsuo Ohta Keisuke Yoshida Hideo Kinebuchi Hikoya Hayatsu 《Mutation research》1993,290(2):303-309
The mutagenicity of human bile was examined in the Ames Salmonella/microsome assay. Bile samples were obtained from the gallbladders resected from patients with cholelithiasis, choledocholithiasis, gallbladder cancer, extrahepatic bile duct cancer and other disease. For extraction of mutagenic components, the bile samples were treated with blue rayon and the adsorbed materials were assayed with Salmonella typhimurium TA98 in the presence of S9 mix. Twenty-four bile samples were tested and positive mutagenic activity was found in 14 samples. A 200-μl bile equivalent material gave 6.3 times as many revertant colonies as the solvent control. With several samples that had undergone two cycles of blue rayon extraction, clear dose-response relationships in mutagenicity were demonstrated. 相似文献
993.
Marie Germaine T. Matchide Saw Yu Yu Hnin Yves M. Mba Nguekeu Elodie Gaële Matheuda Josker Nghokeng Gaetan T. Tabakam Raymonde A. Dzatie Djoumbissie Silvère Augustin Ngouela Yuan-E Lee Mathieu Tene Hiroyuki Morita Maurice Ducret Awouafack 《化学与生物多样性》2023,20(9):e202301127
A new fructofuranoside glycerol, dryoptkirbioside ( 1 ), along with thirteen known compounds ( 2 - 14 ), was isolated from the MeOH extract of Dryopteris kirbi rhizomes by silica gel column chromatography, Sephadex LH-20 column chromatography, and semipreparative HPLC. The structure of the new compound was determined by analyses of its spectroscopic data including nuclear magnetic resonance (NMR), and high-resolution electrospray ionisation mass spectrometry (HR-ESI-MS) and chemical conversions. The hexane-soluble portion and the EAFA fraction showed strong activities against lung (A549), breast (MCF-7), and cervical (HeLa) human cancer cell lines (IC50 values ranging from 4.0 to 8.8 μg/mL). Aspidinol P ( 5 ) and aspidinol B ( 6 ) exhibited moderate to low cytotoxicity on the three cell lines (IC50 values ranging from 20.4 to 58.7 μM). The MeOH extract and hexane-soluble portion had excellent activities against Staphylococcus aureus and Bacillus subtilis (MICs 11.7 and 23.4 μg/mL), whereas the AcOEt- and BuOH-soluble portions were significantly active on S. aureus (MICs 46.9 and 93.8 μg/mL). The main fractions EAFB, EAFC and nBFB displayed excellent activity against S. aureus (MICs 11.7 and 23.4 μg/mL). Aspidinol B ( 6 ) had significant activity, while aspidinol P ( 5 ) was moderately active against S. aureus and B. subtilis (MICs 42.0 and 89.5 μM). 相似文献
994.
Hideki Takanari Joji Morita Hidetaka Yamanaka Kenichiro Yada Asahiko Takahashi Kosaku Izutsu 《Biology of the cell / under the auspices of the European Cell Biology Organization》1994,82(1):51-57
Summary— The pH-related change in morphology of vinblastine (VLB)-induced paracrystals formed in Chinese hamster ovary (CHO) cells was examined immunohistochemically in order to determine both the mechanism of tubulin crystallization and the influence of acidic pHs on cytoskeletal microtubules. Lowering the extracellular pH (pHe) rapidly reduced the intracellular pH (pHi) in CHO cells. Lowering the pHi to near the neutral range significantly accelerated the growth of VLB-induced paracrystals, compared to that of paracrystals formed at a physiological pHe. However, further cytoplasmic acidification caused by the addition of sodium azide into the culture medium induced the disappearance of typical paracrystals and the appearance of a highly organized meshwork of tubulin appearing as short, thick filaments at the light microscopic level. Treatments using different concentrations of VLB at different pHe's showed that low pHi's (6.7 and 6.3) suppressed paracrystal-formation at lower concentrations of VLB (5×10?6 M and 10?5 M). At higher concentrations of VLB (5×10?5 M and 10?4 M), only short filaments were formed at pHi 6. 3. Electron microscopy revealed that the filaments had a ladder-like structure probably consisting of a stacked series of fused rings. This indicates that paracrystals may be modified by extremely low pH. These results show that paracrystals are unstable in living cells and that their formation is regulated by environmental pH. 相似文献
995.
Terao Hiroshi Harada Mamoru Kurosawa Shin Shinomiya Yoshihiro Okamoto Tadao Ito Osamu Sumichika Hiroshi Takenoyama Mitsuhiro Nomoto Kikuo 《Biotherapy》1994,8(2):143-151
Biotherapy - We examined the possibility that Th1 type CD4+ T cells may be an effector against three kinds of syngeneic tumors such as highly immunogenic B16 melanoma (B16) and two poorly... 相似文献
996.
Chloroplasts which were rapidly isolated from illuminated leaves showed activity of ATP hydrolysis at a level much higher than that of the dark control. Under the high-intensity illumination or under repetitive flash excitation, the activated chloroplasts synthesized more ATP than those with a low ATP hydrolysis activity. formed under repetitive flashes was smaller in the activated chloroplasts than in the inactive chloroplasts. The inhibition of ATP yield per flash by valinomycin or nigericin in the presence of K+ was stronger in the inactive chloroplasts than in the activated chloroplast. ATP synthesis in the activated chloroplasts seems to have a lower threshold. 相似文献
997.
Levels of DNA, RNA, protein, ATP, glutathione, and radioactivity associated with [35S]methionine-labeled cellular protein were estimated at various times during the starvation-survival process of a marine psychrophilic heterotrophic Vibrio sp., Ant-300. Values for the macromolecules were analyzed in terms of total, viable, and respiring cells. Electron micrographs (thin sections) were made on log-phase and 5.5-week-starved cells. On a per-cell basis, the levels of protein and DNA rapidly decreased until a constant level was attained. A second method in which radioactive sulfur was used for monitoring protein demonstrated that the cellular protein level decreased for approximately 2.5 weeks and then remained constant. An initial decrease in the RNA level with starvation was noted, but with time the RNA (orcinol-positive material) level increased to 2.5 times the minimum level. After 6 weeks of starvation, 45 to 60% of the cells remained capable of respiration, as determined by iodonitrotetrazolium violet-formazan granule production. Potential respiration and endogenous respiration levels fell, with an intervening 1-week peak, until at 2 weeks no endogenous respiration could be measured; respiratory potential remained high. The cell glutathione level fell during starvation, but when the cells were starved in the presence of the appropriate amino acids, glutathione was resynthesized to its original level, beginning after 1 week of starvation. The cells used much of their stored products and became ultramicrocells during the 6-week starvation-survival process. Ant-300 underwent many physiological changes in the first week of starvation that relate to the utilization or production of ATP. After that period, a stable pattern for long-term starvation was demonstrated. 相似文献
998.
Cyclohexadextrin and maltose bound to soybean beta-amylase and affected the environments of tryptophan and tyrosine residues, producing characteristic difference spectra in the ultraviolet region. The difference spectrum produced by cyclohexadextrin, a competitive inhibitor, had peaks at 285, 292, and 299 nm, while that by maltose, a reaction product, had peaks at 285 and 292 nm and a small trough at around 300 nm. By using the peaks at 292 and 299 nm, the dissociation constants of enzyme-cyclohexadextrin and enzyme-maltose complexes were calculated to be 0.35 mM and 8.1 mM, respectively. The effects of modification of SH groups of beta-amylase on the interaction of the enzyme with these sugars were examined by using beta-amylase carboxymethylated at the SH1 site and the enzyme modified at SH1 and SH2 sites with iodoacetamide or with 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB). The dissociation constants of the enzyme-cyclohexadextrin and enzyme-maltose complexes were not changed by the modification of these SH groups, but the modification of SH2, the so-called essential SH group of soybean beta-amylase, strongly affected the difference spectra produced by maltose. The spectrophotometric titration of beta-amylase by cyclohexadextrin in the presence of maltose showed that cyclohexadextrin and maltose bind to the enzyme competitively, regardless of the modification of SH2. These results indicated that SH2 is located near the binding site of cyclohexadextrin and maltose, but is not involved in the binding of these sugars. 相似文献
999.
A new method for purification of staphylocoagulase by a bovine prothrombin-Sepharose column 总被引:2,自引:0,他引:2
Staphylocoagulase was isolated from a culture filtrate of Staphylococcus aureus, strain st-213, by a two step purification procedure of chromatography on a bovine prothrombin-Sepharose 4B affinity column and gel filtration on Sephadex G-25. The yield of the coagulase activity ranged from 75--83% and the purified preparation gave a single precipitin line in immunodiffusion tests against anti-crude and anti-purified staphylocoagulase sera. However, the final product was shown to contain one major and two minor components by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Chemical analysis of the material indicated that it does not contain any cystine residues and that its NH2-terminal residue is a single isoleucine. 相似文献
1000.
Evidence by electron micrographs for a high incidence of bacteriophage particles in the waters of Yaquina Bay, oregon: ecological and taxonomical implications. 总被引:11,自引:9,他引:2
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A variety of viral particles, the majority of them clearly identifiable as bacteriophages, were found in the seawater of Yaquina Bay, Oregon. These phages were obtained as free particles from the seawater without employing specific hosts for enrichments or further purification in the laboratory. A variety of electron micrographs showing different morphologies of phages as well as phage-bacterium interactions found in the seawater are presented. In the area where the bay received organic enrichment from seafood processing plants, a minimum of 10(4) phage particles per ml was estimated. Since the technique used was designed to concentrate particles 0.2 micrometer in diameter or larger it is assumed that the actual number of phage particles is higher than 10(4) particles per ml. The implications of the presence of such phage concentrations in bays and estuaries with a certain level of eutrophication are of obvious importance in considering the microbial ecology of these environments. 相似文献