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1.
T Nimura M Okada M Shimizu M Kawabe T Itoh M Iwasaki H Kimura T Takeuchi 《The Annals of physiological anthropology》1990,9(4):329-333
Motorcyclists who work in some offices sometimes complained of coldness, pain and numbness of upper limbs. We studied how to discriminate between vibration syndrome and local fatigue of the motorcyclists. Subjects are 42 motorcyclists of an office in Aichi prefecture. 25 of them held several letters in their left hand when they delivered the letters. They complained of coldness, pain and numbness in the left upper limbs more than in the right limbs (p less than 0.01). We think that it is the local fatigue rather than the disorder of vibration syndrome that causes such symptoms. So it is very important to recognize the existence of local fatigue in order to know how to discriminate between vibration syndrome and local fatigue of the motorcyclists. 相似文献
2.
The defatted sclerotia powder was partially hydrolyzed with dilute acid, and the material obtained was fractionated by carbon column chromatography, separated into two disaccharides, three trisaccharides and three tetrasaccharides, respectively. In these hydrolyzates α, α-trehalose, Iaminaribiose, and gentiobiose were identified. 相似文献
3.
4.
Using the cornea of macaque monkey, we demonstrated the relationship between cell density and growth of endothelial cells in vitro. Corneal endothelial cells in a cell sheet grow most actively in regions with cell density of 1000 to 1800 cells/mm2, in explant cultures and cell sheets and in concentrated inocula dissociated cells. Cell morphology was well sustained in these cultures. Cells cultured at a higher cell density retained their potential to proliferate actively, showing clear contrast to cells cultured at a density lower than 200 cells/mm2. When dissociated cells were cultured at a low density and maintained for more than 4 weeks, they gradually lost their growth potential, altered into polymorphonuclear giant cells and eventually dedifferentiated. In addition, cells with no contact with each other did not express growth potential. Density dependent growth was confirmed by measuring the mitotic index against the cell density per square mm from the center to the peripheral regions in cultured explants. It is concluded that the growth pattern of corneal endothelial cells is closely related to cell density, and that growth of these cells might be regulated through intercellular communications. 相似文献
5.
Y Takeuchi T Okumura J Sugatani K Saito 《Archives of biochemistry and biophysics》1987,252(1):206-217
Two types of phospholipase B of Penicillium notatum, the native type and the modified type that is thought to be generated by the introduction of some nicks into the native type of enzyme by the endogenous protease(s), were distinguished on a slab sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis under a nonreducing condition. The native form migrated with a rate corresponding to 95K Da, whereas the modified form migrated more slowly, corresponding to 106K Da, presumably because of its more extended conformation. That the "106K" protein was indeed a nicked product of the "95K" protein was confirmed by amino acid analysis, peptide mapping, N- and C-terminal sequence analyses, and immunoblotting. The peptide fragments (70K and 37K + 32K) comprising the modified protein were isolated by gel filtration in the presence of SDS and 2-mercaptoethanol (the 32K peptide was suggested to be a partial proteolytic product of the 37K peptide). When the "95K" protein was subjected to the same treatment under denaturing condition, it retained a low, but significant, enzymatic activity; in contrast, the separated peptide fragments did not show any significant activity. By a coincubation of these fragments, however, a restoration of enzymatic activity was observed through a reformation of the active complex, corresponding to the original modified protein. The enzymatic activity of this complex was further increased by a treatment with guanidine X HCl, followed by dialysis. The association of peptide fragments appears to occur through the formation of interpeptidal disulfide bonds. 相似文献
6.
Sulfhydryl modification and activation of phenylalanine hydroxylase by dinitrophenyl alkyl disulfide
S Koizumi T Suzuki S Takahashi K Satake T Takeuchi H Umezawa T Nagatsu 《Biochemistry》1987,26(20):6461-6465
A new family of asymmetric thiol-disulfide exchange reagents, the dinitrophenyl alkyl disulfides (DNPSSR), was used to modify rat liver phenylalanine hydroxylase. The results indicate that the enzyme has two different types of reactive sulfhydryl (SH) residues per subunit. One SH residue was modified selectively by a DNPSSR having a neutral and hydrophilic alkyl group, and this modification was accompanied by appreciable activation of enzyme; the other SH residue was modified only by an anionic DNPSSR, and this modification did not result in activation. The catalytic properties of phenylalanine hydroxylase activated by DNPSSR were similar to those of the N-ethylmaleimide- (NEM-) modified enzyme, but the process of activation by DNPSSR was quite different from modification with NEM. An analysis of the reaction kinetics of the modification and of catalysis by the modified enzyme suggests that DNPSSR modification causes a change in the subunit interaction leading to a loss of the negative cooperativity normally seen with phenylalanine hydroxylase. 相似文献
7.
Nitrile hydratase of Pseudomonas chlororaphis B23. Purification and characterization 总被引:14,自引:0,他引:14
T Nagasawa H Nanba K Ryuno K Takeuchi H Yamada 《European journal of biochemistry》1987,162(3):691-698
Nitrile hydratase of Pseudomonas chlororaphis B23 was completely stabilized by the addition of 22 mM n-butyric acid. The enzyme was purified from extracts of methacrylamide-induced cells of P. chlororaphis B23 in eight steps. At the last step, the enzyme was crystallized by adding ammonium sulfate. The crystallized enzyme appeared to be homogeneous from analysis by polyacrylamide gel electrophoresis, analytical ultracentrifuge, and double diffusion in agarose. The enzyme has a molecular mass of about 100 kDa and consists of four subunits identical in molecular mass (approximately 25 kDa). The enzyme contained approximately 4 mol iron/mol enzyme. The concentrated solution of highly purified nitrile hydratase had a pronounced greyish green color and exhibited a broad absorption in visible range with a absorption maxima at 720 nm. A loss of enzyme activity occurred in parallel with the disappearance of the absorption in the visible range under a variety of conditions. The enzyme catalyzed stoichiometrically the hydration of nitrile to amide, and no formation of acid and ammonia were detected. The enzyme was active toward various aliphatic nitriles, particularly, nitriles with 3-6 carbon atoms, e.g. propionitrile, n-butyronitrile, acrylonitrile and cyclopropyl cyanide, served as the most suitable substrates. 相似文献
8.
Atsuko Matsuoka Akiko Hirosawa Shinasku Natori Shigeo Iwasaki Toshio Sofuni Motoi Ishidate Jr. 《Mutation research》1989,215(2):179-185
The chromosomal aberration test using a Chinese hamster lung cell line (CHL) was carried out on ptaquiloside and its related compounds, hypoloside B, hypoloside C, illudin M and illudin S. Ptaquiloside induced chromosomal aberrations at doses as low as 4.5 μg/ml (0.0113 mM). The clastogenic effect was ph-dependent. The same activity was observed at a 90-fold higher dose at pH 5.3 in the culture medium compared with the activity at pH 74. or pH 8.0. Both hypoloside B and hypoloside C were also clastogenic at almost the same dose levels as that of ptaquiloside. Illudin M and illudin S were also potet clastogens and induced aberrations at much lower doses than ptaquiloside. These results suggest that the clastogenic effect is involved in the mechanism of carcinogenic potency of ptaquiloside in animals. 相似文献
9.
Yuichi Takeuchi Megumi Akizuki Hideyuki Shimizu Noriaki Kondo Kiyoshi Sugahara 《Physiologia plantarum》1989,76(3):425-430
Cucumber ( Cucumis sativus L. cv. Natsusairaku 3) seedlings were grown in a growth cabinet under UV-B (290–320 nm) irradiation (equivalent to the UV-B radiation normally incident at Tokyo, 36°N latitude, during clear sky conditions in mid-april on a weighted daily fluence basis) and a UV-B-free control condition. UV-B irradiation inhibited the growth of the cotyledons, i.e. the increase in area, and increase in fresh and dry weights of the cotyledons. The greatest inhibition rate was observed in the increase in area, causing a significant increase in specific leaf weight (the ratio of weight to area). UV-B irradiation had no significant effect on DNA and RNA contents in the cotyledons, but decreased protein content slightly. In contrast, the irradiation reduced the amounts of organic acids and soluble sugars, indicating that primary carbon metabolism was very sensitive to UV-B radiation. UV-B irradiation lowered the photosynthetic activity in the cotyledons without any effect on chlorophyll content and respiratory activity. These results indicate that UV-B radiation at the ambient level may act as a physiological stress in some UV-sensitive plants. 相似文献
10.
M Sobue J Takeuchi T Fukatsu T Nagasaka N Nakashima T Ogura T Katoh K Yoshida 《Stain technology》1989,64(1):43-47
Dermatan sulfate proteoglycan chains were detected in tissue sections treated with chondroitin B-lyase (0.01 units/ml) in 20 mM Tris-HCl (pH 8.0) for 1 hr, followed by staining with antibody 9A2 specific for unsaturated uronic acid coupled to N-acetylgalactosamine-4 sulfate. In contrast, after treatment with chondroitin B-lyase, no positive staining was observed with antibodies 3B3 and 1B5 which react to the unsaturated uronic acid coupled to N-acetylgalactosamine 6-sulfate and unsaturated uronic acid coupled to N-acetylgalactosamine, respectively. The distribution of dermatan sulfate thus revealed was confirmed by comparison with that found by monoclonal antibody 6B6 which reacts with small proteoglycans carrying dermatan sulfate side chains. The localization of positive staining in fibrous connective tissues was almost identical with these two procedures. 相似文献