title: New feature of delayed luminescence: preillumination-induced concavity and convexity in delayed luminescence decay curve in the green alga Pseudokirchneriella subcapitata.
abstract: A new method for measuring delayed luminescence (delayed fluorescence) employs preillumination and a dark waiting period before normal excitation. The preillumination results in a concavity and a convexity in the decay curve in delayed luminescence in the green alga Pseudokirchneriella subcapitata. Formation of the concavity and the convexity is not affected by excitation wavelength (680 nm and 700 nm). However, the concavity and the convexity progressively decrease as the dark waiting period increases after preillumination. The formation of the concavity and the convexity was inhibited by exposure to the electron transport inhibitors DBMIB (644 microg/L, 2.0 microM) and Antimycin A (55 microg/L, 0.1 microM). Samples exposed to DBMIB exhibited noticeable reduction in the concavity, whereas samples exposed to Antimycin A exhibited pronounced reduction in the convexity. There is a possibility that the formation and disappearance of the concavity and the convexity are due to the reduction-oxidation state of the plastoquinone pool and the cyclic electron transport. We expect this method being useful in evaluating the effects of chemicals (particularly toxic chemicals) on photosynthetic reactions, and the method may also help to resolve questions regarding the source of long delayed luminescence.
authors.affiliation: Central Research Laboratory, Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita-Ku, Hamamatsu City, Shizuoka Prefecture 434-8601, Japan. katumata@crl.hpk.co.jp
authors.forename: Masakazu
authors.initials: M
authors.lastname: Katsumata
authors.forename: Ayano
authors.initials: A
authors.lastname: Takeuchi
authors.forename: Kimiko
authors.initials: K
authors.lastname: Kazumura
authors.forename: Takashi
authors.initials: T
authors.lastname: Koike
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology; D000968:Antimycin A / Q000494:pharmacology; D001681:Biological Assay; D000460:Chlorophyta / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects*; D003991:Dibromothymoquinone / Q000494:pharmacology; D008027:Light; D008163:Luminescent Measurements / Q000295:instrumentation; D008958:Models, Molecular; D045331:Photosystem I Protein Complex / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000378:metabolism; D013997:Time Factors
chemical_list: D000935:Antifungal Agents; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D003991:Dibromothymoquinone; D000968:Antimycin A