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Rabi K. Prusti Pill-Soon Song Donat-Peter Häder Maria Häderi 《Photochemistry and photobiology》1984,40(3):369-375
The effects of caffeine, ionophores and calcium flux blockers on the step-up photophobic response, phototactic orientation and the intracellularly recorded, light-induced electrical action potential were studied in the ciliate, Stentor coeruleus . Caffeine alters the absorption and CD spectra and enhances the fluorescence of the photoreceptor pigment, stentorin. Independent of its effects on the spectroscopic properties of the photoreceptor pigment, caffeine shortens the photophobic response time by enhancing the Ca2+ conductivity of membranes, while Ca2+ flux blockers (LaCI3 or ruthenium red) prolong it; both effects cancel each other. Evidence is presented that phototactic orientation is brought about by repetitive photophobic responses, since a change in the phobic response time results in a decreased accuracy of phototaxis. 相似文献
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Ki-Chun Yang Rabi K. Prusti Edward B. Walker † Pill-Soon Song ‡ Masakatsu Watanabe § Masaki Furuya § 《Photochemistry and photobiology》1986,43(3):305-310
Abstract— Stentorin acts as the photoreceptor for the step-up photophobic and negative phototactic responses in Stentor coeruleus . The chromophore of stentorin appears to be hypericin which is linked to apoprotein. In addition to the photomovement responses of the organism, S. coeruleus was found to be photodynamically sensitive to light absorbed by the hypericin chromophore, as the apparent action spectrum for the photodynamic killing matches the absorption spectrum of stentorin. The protective effect of β-carotene and crocetin on the photodynamic killing of S. coeruleus suggests that singlet oxygen generated by the stentorin-sensitization plays an important role, according to the so-called Type II mechanism of photosensitization. The generation of singlet oxygen via hypericin triplet was confirmed by in vitro photooxidation of tryptophan as a substrate. The photodynamic killing was more effective in deuterium oxide than in H2 O in both the photosensitization by stentorin (endogenous) and added hypericin (exogenous). These results are consistent with the involvement of singlet oxygen in the photodynamic killing of S. coeruleus . 相似文献
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Moghal Zubair Khalid Baig Banchhanidhi Prusti Shouvik Bhuin 《Phosphorus, sulfur, and silicon and the related elements》2020,195(7):526-535
AbstractMolecular anthracene has been used as an arene in the Friedel-Crafts (FC) type arylation reaction of anthracenyl-α-hydroxyphosphonate in the presence of acid. A diverse product formation is observed, in which anthracene unit is found to be linked through its C1 position with α-C of phosphonate. Interestingly, the molecular conformation (X-ray structure) of this phosphonate reveals one of the bond angles of a tetrahedral carbon as 118° which is close to the C of sp2 character. Further, molecular anthracene is also recognized to attack at the C10 position of 9-anthracenylphosphonate through C1 or C2 or C9 atoms and the structures of three isomeric phosphonates are established with the help of 1H and 31P NMR studies. The bis-anthracenyl compounds with a P-CH2 unit have been successfully utilized in Horner-Wadsworth-Emmons (HWE) reactions to afford extensive bis-anthracenyl-linked π-conjugates. 相似文献
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