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排序方式: 共有487条查询结果,搜索用时 15 毫秒
101.
Recombinant human m-calpain was produced in a soluble form at a level of 20 mg/liter of Sf-9 cell culture by the coexpression of recombinant human m-calpain large (m80K) and small (30K) subunits using a baculovirus expression system. The expressed m-calpain was purified by sequential column chromatographies on DEAE-Toyopearl, gel-filtration, and Mono Q by the same method used to purify native m-calpain. The recombinant m-calpain had a specific activity of 691 U/mg and a Ka value (Ca2+ requirement for 50% caseinolysis activity) of 0.4 mM, which are essentially identical to those of native rabbit m-calpain. A mutant m-calpain large subunit, m-C105S-80K, where the active-site cysteine-105 is converted to serine by site-directed mutagenesis, was coexpressed with 30K in Sf-9 cells, purified, and characterized. m-C105S-calpain does not degrade casein nor an artificial tetra-peptide substrate, succinyl-Leu-Leu-Val-Tyr-MCA. Further, it shows no autolytic activity with Ca2+. This is the first report of the large-scale production of a fully active m-calpain species in the baculovirus system. 相似文献
102.
103.
Preparation of B4C-mixed graphite by pressureless sintering and its air oxidation behavior 总被引:1,自引:0,他引:1
B4C-mixed graphites with a boron concentration ranging from 3 to 32 mass% were prepared by pressureless sintering. For fabrications of these materials, a mixture of mesocarbon-microbeads and boron carbide powders was used. Final heat treatment temperature employed was around 2000 °C. The bulk densities of the materials were from 1.78 to 1.85 g/cm3, and the flexural strength was in the range of 44–87 MPa. These materials have a good machinability with shore hardness less than 71. Oxidation loss by air of this material with a total boron concentration more than approx. 10 mass% appeared to be almost completely suppressed at temperatures below 800 °C, where a little weight gain was observed due to the formation of boron oxide. In the temperature range from 900 to 1300 °C, appreciable oxidation loss was observed and the rate decreased as boron concentration increased. 相似文献
104.
K Hino K Fujii M Korenaga C Murakami M Okazaki M Okuda K Okita 《Canadian Metallurgical Quarterly》1997,42(12):2476-2481
Hepatitis C virus (HCV) circulates as particles having differing buoyant densities. Changes in the relative proportions of virus particles of different densities were examined in 19 patients with chronic hepatitis C: 6 without (group A) and 13 with (group B) abnormal serum alanine aminotransferase (ALT) levels. High- and low-density virus particles were separated by differential flotation centrifugation. The numbers of high-density particles consistently exceeded that of low-density particles in all patients in group A, whereas the titers of both types of particles were the same at least once in 7 of 10 patients sampled at two time points in group B. The ALT level significantly increased <2 months later (P < 0.05) when the titers of both types of particles were the same in patients in group B. Thus, we found a correlation between the relative numbers of circulating low-density HCV particles and disease activity in chronic hepatitis C patients. 相似文献
105.
106.
An aging test for AlGaInP/GaInP visible-light lasers (?L = 678 nm) with 3?5 mW lasing output power was carried out for over 2000 h at room temperature. Significant degradation has not been observed during this test. The results indicate that the AlGaInP laser diodes have a considerable lifetime, suitable for practical use. 相似文献
107.
O Hino 《Canadian Metallurgical Quarterly》1997,24(8):924-929
Cancer is a heritable disorder of somatic cells. Environment and hereditary both operate in the origin of human cancer. Hereditary cancer is rare, but it has served as a useful model in the understanding of carcinogenesis. A number of cancer genes have been identified by the study of hereditary cancers and implicated in sporadic forms of the same tumors. In this article, I reviewed Knudson's famous "two-hit" hypothesis of tumor suppression. 相似文献
108.
Masanobu Kamitakahara Eri Tatsukawa Yasuaki Shibata Shota Umemoto Taishi Yokoi Koji Ioku Tohru Ikeda 《Journal of materials science. Materials in medicine》2016,27(5):97
In addition to calcium phosphate-based ceramics, glass-based materials have been utilized as bone substitutes, and silicate in these materials has been suggested to contribute to their ability to stimulate bone repair. In this study, a silicate-containing α-tricalcium phosphate (α-TCP) ceramic was prepared using a wet chemical process. Porous granules composed of silicate-containing α-TCP, for which the starting composition had a molar ratio of 0.05 for Si/(P + Si), and silicate-free α-TCP were prepared and evaluated in vivo. When implanted into bone defects that were created in rat femurs, α-TCP ceramics either with or without silicate were biodegraded, generating a hybrid tissue composed of residual ceramic granules and newly formed bone, which had a tissue architecture similar to physiological trabecular structures, and aided regeneration of the bone defects. Supplementation with silicate significantly promoted osteogenesis and delayed biodegradation of α-TCP. These results suggest that silicate-containing α-TCP is advantageous for initial skeletal fixation and wound regeneration in bone repair. 相似文献
109.
Comparative Study of Interfacial and Biological Properties in <Emphasis Type="SmallCaps">d</Emphasis>-Glycerate-Derived Surfactants 下载免费PDF全文
Shun?Sato Shota?Nagata Dai?Kitamoto Yutaka?Takahashi Yukishige?Kondo Hiroshi?HabeEmail author 《Journal of the American Oil Chemists' Society》2017,94(11):1393-1401
The effects of hydrophobic chain length on the interfacial and biological properties of diacyl d ‐glyceric acid (d ‐GA) sodium salts were evaluated based on interfacial tension analyses, dynamic light scattering (DLS), and antitrypsin activity. Of the four synthesized d ‐GA‐derived surfactants [dihexanoyl d ‐GA sodium salt (diC6GA‐Na), dioctanoyl d ‐GA sodium salt (diC8GA‐Na), didecanoyl d ‐GA sodium salt (diC10GA‐Na), and dilauroyl d ‐GA sodium salt (diC12GA‐Na)], only those with C6, C8, and C10 acyl chains were investigated because diC12GA‐Na were insoluble at room temperature. Together with our previous results, surface tensions at the critical micelle concentration (CMC) were 33.9 mN/m for diC6GA‐Na, 25.5 mN/m for diC8GA‐Na, and 27.9 mN/m for diC10GA‐Na. Evaluation of assembly size via DLS and optical microscopy revealed that diC8GA‐Na and diC10GA‐Na formed large associates with average sizes ranging from 50 to 200 μm at concentrations 4–5 times greater than their CMC, whereas diC6GA‐Na did not form such associates. In tryptic hydrolysis studies using Nα‐benzoyl‐dl ‐arginine‐4‐nitroanilide as a substrate, diC8GA‐Na exhibited an inhibitory effect on trypsin (trypsin specific activity: 0.26 ± 0.045 U/mg‐protein) greater than that of diC10GA‐Na (0.39 ± 0.10 U/mg‐protein), whereas diC6GA‐Na did not show antitrypsin activity. These results show that diC8GA‐Na was the most bioactive of the evaluated diacyl d ‐glycerate surfactants. 相似文献
110.
(4<Emphasis Type="Italic">Z</Emphasis>,15<Emphasis Type="Italic">Z</Emphasis>)-Octadecadienoic Acid Inhibits Glycogen Synthase Kinase-3β and Glucose Production in H4IIE Cells 下载免费PDF全文
Jun Yoshida Shota Uesugi Tetsuaki Kawamura Ken-ichi Kimura Dawei Hu Shuang Xia Naoki Toyooka Masao Ohnishi Hideki Kawashima 《Lipids》2017,52(3):295-301
Many uncommon non-methylene-interrupted fatty acids (NMI FA) are present in limpet gonads, but their biological properties remain unknown. To investigate new biological effects of naturally occurring NMI FA in eukaryotic cells, the biological activities of structurally analogous (4Z,15Z)-octadecadienoic acid (1), (9Z,20Z)-tricosadienoic acid (2), and (12Z,23Z)-hexacosadienoic acid (3) were examined by using a yeast-based drug-screening system using the Ca2+-sensitive mutant strain, Saccharomyces cerevisiae (zds1Δ erg3Δ pdr1Δ pdr3Δ). Among 1–3, 1 showed restored growth activity at a dose of 80 µg/disc in the mutant yeast strain. This phenotype suggests that 1 suppresses Ca2+-signaling of the mutant yeast through inhibition of glycogen synthase kinase-3β (GSK-3β) or calcineurin pathways or both. From this result, the inhibitory activity of 1–3 against GSK-3β was further determined. 1–3 showed potent inhibitory activity against GSK-3β with IC50 values ranging from 8.7 to 21.9 µM. Inhibition of GSK-3β reduces gene expression of the gluconeogenic key enzymes in liver, so we analyzed glucose production in rat hepatoma H4IIE cells to assess GSK-3β inhibitory activity of 1–3. Acid 1 inhibited glucose production at 25 µM in H4IIE cells. Our results would open up new possibilities for an anti-diabetic effect of 1 and might provide important insights into understanding the biological properties of naturally occurring NMI FA. 相似文献