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91.
Organomercurial-volatilizing bacteria in the mercury-polluted sediment of Minamata Bay, Japan. 总被引:2,自引:2,他引:0 下载免费PDF全文
A total of 4,604 bacterial strains isolated from the sediments of Minamata Bay and nearby low-level-mercury stations (control stations) were screened for the ability to volatilize mercury from inorganic and organic mercurial compounds. The strains that volatilize mercury from several kinds of organomercurials were found only in the sediments of Minamata Bay. 相似文献
92.
Seasonal and areal features of the lagoonal environment in Lake Nakanoumi,a shallow coastal lagoon in Japan 总被引:1,自引:1,他引:0
Lake Nakanoumi is a shallow coastal lagoon connected with the Japan Sea by a narrow channel. Over the past decade, land reclamation resulted in a 33% reduction of the lagoon's surface area. The remaining water basin of Lake Nakanoumi is scheduled to be artificially freshened to supply irrigation water for the newly reclaimed lands. This paper deals with the seasonal and areal features of the lagoonal environment prior to the beginning of the artificial desalinization. 相似文献
93.
Yoshiteru Harada Kunio Tanaka Yasushiro Uchida Akinori Ueno Sachiko Oh-ishi Yamashita Kowa Masataka Ishibashi Hiroshi Miyazaki Makoto Katori 《Prostaglandins & other lipid mediators》1982,23(6)
Injection of γ-carrageenin into t he pleural cavity of rats caused the accumulation of the pleural exudate. When levels of prostaglandins (PGs) and thromboxane (TX) B2 were quantified by gas chromatography-mass spectrometry as their methyl ester (ME)-dimethyllisopropylsilyl (DMiPS) ether or ME-methoxine-DMiPS ether derivatives, 6-keto-PGF1α reached the maximum at 1 hr after carrageenin, then PGE2 and TXB2 showed peaks at 3 hr and waned off before 9 hr. he PGF2α level was kept low, but PGD2, PGE1 and PGF1α were not detected. Aspirin (100 mg/kg, i.p.) significantly decreased the PG and TXB2 levels and suppressed the rate of plasma exudation until 5 hr, but did not at 7 hr, when it was measured by the amount of exuded pontamine sky blue injected intravenously. OKY-025 (300 mg/kg, i.p.), a selective TXA synthetase inhibitor, and tranylcypromine (20 mg/kg, i.p.), a PGI synthetase inhibitor, could not extensively inhibit the accumulation of the exudate. These results suggest that the cyclooxygenase products of arachidonic acid, particularly PGE2, definitely play an important role in the exudation during the first 5 hr. 相似文献
94.
Hiroshi Hayakawa Kanji Ishizaki Masao Inoue Takashi Yagi Mutsuo Sekiguchi Hiraku Takebe 《Mutation research》1981,80(2)
DNA-repair characteristics of xeroderma pigmentosum belonging to complementation group F were investigated. The cells exhibited an intermediate level of repair as measured in terms of (1) disappearance of T4 endonuclease-V-susceptible sites from DNA, (2) formation of ultraviolet-induced strand breaks in DNA, and (3) ultraviolet-induced unscheduled DNA synthesis during post-irradiation incubation. The impaired ability of XP3YO to perform unscheduled DNA synthesis was restored, to half the normal level, by the concomitant treatment with T4 endonuclease V and ultraviolet-inactivated Sendai virus. It is suggested that xeroderma pigmentosum cells of group F may be defective, at least in part, in the incision step of excision repair. 相似文献
95.
Changes of thick filament structure during contraction of frog striated muscle. 总被引:6,自引:3,他引:3 下载免费PDF全文
The strongest myosin-related features in the low-angle axial x-ray diffraction pattern of resting frog sartorius muscle are the meridional reflections corresponding to axial spacings of 21.4 and 14.3 nm, and the first layer line, at a spacing 42.9 nm. During tetanus the intensities of the first layer line and the 21.4-nm meridional decrease by 62 and 80% respectively, but, when the muscle is fresh, the 14.3-nm meridional intensity rises by 13%, although it shows a decrease when the muscle is fatigued. The large change in the intensity of the 21.4-nm meridional reflection suggests that the projected myosin cross-bridge density onto the thick filament axis changes during contraction. The model proposed by Bennett (Ph.D. Thesis, University of London, 1977) in which successive cross-bridge levels are at 0,3/8, and 5/8 of the 42.9-nm axial repeat in the resting muscle, passing to 0, 1/3, and 2/3 in the contracting state, can explain why the 21.4-nm reflection decreases in intensity while the 14.3-nm increases when the muscle is activated. The model predicts a rather larger increase of the 14.3-nm reflection intensity during contraction than that observed, but the discrepancy may be removed if a small change of shape or tilt of the cross-bridges relative to the thick filament axis is introduced. The decrease of the intensity of the first layer line indicates that the cross-bridges become disordered in the plane perpendicular to the filament axis. 相似文献
96.
Ken Inouye Kunio Watanabe Yoshihiro Tochino Masashi Kobayashi Yukio Shigeta 《Biopolymers》1981,20(9):1845-1858
The trypsin-catalyzed coupling of bovine (Boc)2-desoctapeptide (B23-B30)-insulin with synthetic octapeptides, H-Gly-X2-X3-X4-Thr-Pro-Lys(Boc)-Thr-OH (X2 = Phe or Ala, X3 = Phe or Ala, X4 = Tyr or Ala), followed by deprotection and purification produced the [AlaB24, ThrB30]-, [AlaB25, ThrB30]-, and [AlaB26, ThrB30]-analogs of bovine insulin in yields of 32, 35, and 32%, respectively. The biological activity of these analogs decreased in the order, normal insulin ([ThrB30]-bovine insulin) = AlaB26-insulin > AlaB25-insulin > AlaB24-insulin, as assayed for receptor binding and some other biological effects, in contrast with the corresponding Leu-analogs of human insulin, in which the activity decreased in the order, normal insulin > LeuB24-insulin > LeuB25-insulin. The affinity to insulin antibodies greatly diminished in both AlaB24-insulin and LeuB24-insulin but not in the B25-substituted analogs. The CD spectra of the Leu- and the Ala-analogs were compared with those of normal insulins to show that no apparent correlation seems to exist between the decrease in biological activity and the conformational changes observed in solution. The effects of organic solvents on the peptide-bond equilibrium and on the stability of trypsin are also discussed. 相似文献
97.
Spectroscopic demonstration of an initial stage of the complex of D-amino acid oxidase and its substrate D-alpha-aminobutyric acid 总被引:1,自引:0,他引:1
D-Amino acid oxidase [D-amino acid: O2 oxidoreductase (deaminating), EC 1.4.3.3] was anaerobically mixed with its substrate D-α-aminobutyric acid at ?10°C and paH1 7 which were apart from their maxima for the enzymatic reaction. By an ordinary self-recording spectrophotometer, the absorption spectrum of an initial stage of the complex could be observed. The spectrum was in principle similar to that of the complex of this enzyme with benzoate, the enzyme-substrate complex model. The spectroscopic observation revealed that this species is in an equilibrium with the purple intermediate, a strong charge transfer complex between the enzyme and its substrate neutral D-amino acid. 相似文献
98.
99.
1. Progesterone inhibited D-amino acid oxidase (D-amino acid : O2 oxidoreductase (deaminating), EC 1.4.3.3) in competition with its substrate, D-alanine. Binding of progesterone brought about the increase in both fluorescence intensity and fluorescence polarization of FAD, which indicates that the environment surrounding FAD chromophore is modified due to a conformational change in the apoenzyme. 2. Ethinyl estradiol, testosterone, testosterone propionate, corticosterone and aldosterone also inhibited the enzyme slightly in the same manner. Their binding also produced a slight increase in FAD fluorescence without decreasing the fluorescence polarization. 3. Cholesterol did not inhibit the enzyme, though it increased the fluorescence polarization of FAD. This indicates the binding of cholesterol with the enzyme at a site other than the substrate binding site. 相似文献
100.
The regulation by adenylates of activities of various partial electron transport systems in spinach chloroplasts was studied using systems from H2O to 2,5-dimethyl-p-benzoquinone, H2O to 2,6-dichlorophenolindophenol, reduced 2,6-dichlorophenolindophenol to methyl viologen, and H2O to methyl viologen or ferricyanide. Adenylates regulated all of them. The ratio of the amount of esterified Pi (P) to that of electrons transported (e) in coupling with phosphorylation manifested that there are two phosphorylation sites: one between H2O and 2,5-dimethyl-p-benzoquinone or 2,6-dichlorophenolindophenol and another between reduced 2,6-dichlorophenolindophenol and methyl viologen, under the proposed stoichiometries,i.e., P/H+=0.5 and H+/e=1, where H+ is the amount of protons pumped by electron transport (= those translocated during phosphorylation), when the basal electron transport (the part not regulated by adenylates) was excluded. The effects of pH, phlorizin, and methylamine on the adenylate regulation of electron transport, and the stimulation profile of electron transport coupled with quasiarsenylation suggested no distinction between the two phosphorylation sites. 相似文献