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21.
Yuichi Takeuchi Reiko Fukumoto Hirokazu Kasahara Takeshi Sakaki Mitsutoshi Kitao 《Plant cell reports》1995,14(9):566-570
Cotyledons excised from dark-grown seedlings of cucumber (Cucumis sativus L.) were cultured in vitro under UV radiation at different wavelengths, obtained by passage of light through cut-off filters with different transmittance properties. Growth and the synthesis of chlorophyll (Chl) in cotyledons were inhibited and malondialdehyde was accumulated upon irradiation at wavelengths below 320 nm. Exogenous application of scavengers of free radicals reversed the growth inhibition induced by UV-B. Measurement of the fluorescence of Chl a suggested that electron transfer in photosystems was affected by UV-B irradiation. On the basis of these results, the involvement is postulated of active species of oxygen in damages to thylakoid membranes and the growth inhibition that are induced by UV-B irradiation.Abbreviations Chl
chlorophyll
- Fm
maximal fluorescence (dark)
- Fm
maximal fluorescence (light)
- Fv
variable fluorescence (dark)
- Fv
variable fluorescence (light)
- MDA
malondialdehyde
- O2
Superoxide radical
- PS
photosystem
- qN
non-photochemical quenching of fluorescence
- qP
photochemical quenching of fluorescence
- UV-BBE
biologically effective UV-B radiation
- WL(T = 0.5)
wavelength at which 50% transmittance occurs 相似文献
22.
Effect of N-methylation of phosphatidylethanolamine on the fluidity of phospholipid bilayers 总被引:2,自引:0,他引:2
M Mio M Okamoto M Akagi K Tasaka 《Biochemical and biophysical research communications》1984,120(3):989-995
The effect of N-methylphosphatidylethanolamine on phase transition and the fluidity of the liposomes made of dipalmitoylphosphatidylcholine or phosphatidylethanolamine was studied by the steady-state fluorescence polarization method and differential scanning calorimetry. N-methylation of phosphatidylethanolamine caused a decrease of fluidity of liposomes made of dipalmitoylphosphatidylcholine, but had little effect on dipalmitoylphosphatidylethanolamine. The liposomes prepared with both phosphatidylcholine and N-methylphosphatidylethanolamine and also phosphatidylethanolamine and N-methylphosphatidylethanolamine could be composed of solid solution and exhibited symmetric phase diagram. 相似文献
23.
Bisulfite reductase of Desulfovibrio vulgaris: explanation for product formation. 总被引:4,自引:4,他引:0 下载免费PDF全文
Bisulfite reductase, purified from Desulfovibrio vulgaris, was coupled with the pyruvate phosphoroclastic reaction. Moderate to low reducing conditions resulted in the formation of trithionate; however, when the concentration of reductant was high, a mixture of trithionate and thiosulfate was formed. Sulfide was also a detectable product, but only when the concentration of bisulfite was low. Flavodoxin mediated native coupling between bisulfite reductase and the phosphoroclastic reaction. A model for bisulfite reductase activity is proposed. 相似文献
24.
A new germacranolide isolated from M. sieboldii was shown to be 15-acetoxycostunolide by spectroscopic and chemical methods. 1H NMR spin decoupling and NOE experiments in the presence of a lanthanide shift reagent were used for structure elucidation. 相似文献
25.
Giuliano Armando E. Irie Reiko F. Morton Donald L. 《Cancer immunology, immunotherapy : CII》1981,10(4):243-249
Summary The oncofetal antigen-I (OFA-I) has been defined as an immunogenic antigen that is expressed on human cancer cells and is cross reactive with fetal brain tissue. Quantitative variations in the expression of OFA-I among different cultured melanoma cell lines were determined by absorption techniques based on functionally monospecific anti-OFA-I serum. Allo-antibodies were removed by absorption with lymphoblasts autologous to an OFA-I-positive target cell. Functional monospecificity toward OFA-I was confirmed by complete absorption with a specimen of fetal brain but not by liver from the same fetus.Of 14 melanoma cell lines tested, two did not express OFA-I, whereas 12 expressed the antigen to varying degrees. Five of the cell lines were highly antigenic, and serum absorbed with 5×105 of any of these cell lines could reduce the anti-OFA-I titer (1 : 96) at least four-fold. OFA-I was detected on biopsied melanomas autologous to the antigenic cultured cells. The ability to select highly antigenic cell lines could be useful in further attempts to characterize OFA-I and to monitor tumor immunity in vitro. Antigenic cell lines may improve the response of patients treated in trials of immunotherapy. 相似文献
26.
Toshihiko Ubuka Masahiro Kinuta Reiko Akagi Shozo Kiguchi Miyabi Azumi 《Analytical biochemistry》1982,126(2):273-277
A procedure for the simultaneous preparation of S-sulfo-l-cysteine and l-alanine 3-sulfinic acid is described. The method is based on the quantitative reaction between sulfite and S-(2-amino-2-carboxyethylsulfonyl)-l-cysteine. The yield was 95% for S-sulfo-l-cysteine and 91% for l-alanine 3-sulfinic acid. The reaction was also applied to the quantitative determination of sulfite in biological materials. In this procedure, sulfite reacts with S-(2-amino-2-carboxyethylsulfonyl)-l-cysteine. Separation of the reaction product, S-sulfo-l-cysteine, is done by ion-exchange fractionation, and it is determined with acid ninhydrin reagent 2 (M. K. Gaitonde, 1967, Biochem. J.104, 627–663). The recovery was 96.8 ± 0.3%. 相似文献
27.
Synthesis of two ω-aldehydoalkyl 1-thioglycosides of d-glucopyranose and of d-galactopyranose is described. 3-Oxopropyl and 2-oxoethyl 1-thioglycosides were prepared by treating a tetra-O-acetyl-1-thioaldose with either acrolein or 2-bromoacetaldehyde, followed by O-deacetylation under mild conditions. These ω-aldehydoalkyl 1-thioglycosides were successfully attached to bovine serum albumin (BSA) by reductive alkylation as described previously. With the 3-oxopropyl 1-thioglycosides, much higher levels of sugar attachment (e.g., ~80 mol of sugar per mol of BSA) were attained than hitherto possible with any sugar derivative tested. 相似文献
28.
29.
Shin Masateru; Wakita Rie; Yamasaki Yohsuke; Oshino Reiko 《Plant & cell physiology》1981,22(2):343-346
The heavier form of ferredoxin-NADP+ reductase was extractedfrom spinach leaves or chloroplasts and isolated as the majorfraction at high ionic strengths with ammonium sulfate or sodiumchloride. At low ionic strengths, the form with the higher molecularweight was relatively unstable and was converted gradually intothe lower form. We concluded that the enzyme exists in vivoas the form with the higher molecular weight.
1Present address: Market Development Department, Shionogi &Co. LTD., 5-Sagisu, Fukushima-ku, Osaka 553, Japan. (Received December 16, 1980; Accepted January 19, 1981) 相似文献
30.
Akitane Mori Masayuki Akagi Yasuto Katayama Yoko Watanabe 《Journal of neurochemistry》1980,35(3):603-605
: Guanidino compounds in the cobalt-induced epileptogenic cerebral cortex of cats were fluorometrically analysed by a JASCO G-520 guanidino compounds analyser, and an unknown high peak was observed in the chromatogram that was identical to the peak of authentic α-guanidinoglutaric acid. In another experiment, the substance was extracted from the cobalt focus tissue, converted into dimethylpyrimidyl derivative-butylester, and analysed by a GC/MS technique. The mass spectrum of the substance was identical to the dimethylpyrimidyl derivative of α-guanidinoglutaric acid butylester (M+= 365). 相似文献