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IN VIVO MEASUREMENT OF ACTIVE OXYGEN PRODUCTION IN THE BROWN ALGA FUCUS EVANESCENS USING 2′,7′‐DICHLOROHYDROFLUORESCEIN DIACETATE 1
Author(s) -
Collén Jonas,
Davison Ian R.
Publication year - 1997
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.0022-3646.1997.00643.x
Subject(s) - photosynthesis , catalase , paraquat , biology , algae , hydrogen peroxide , oxygen , photosystem ii , oxygen evolution , biophysics , in vivo , nuclear chemistry , botany , biochemistry , chemistry , enzyme , microbiology and biotechnology , organic chemistry , electrode , electrochemistry
Intracellular production of active oxygen in the brown alga Fucus evanescens C. Ag. was studied by measuring the capacity for in vivo conversion of 2′,7′‐dichlorohydrofluorescein diacetate (DCFH‐DA) to the fluorescent dye 2′,7′‐dichlorofluorescein (DCF), both in emersed and immersed seaweeds. Algae were incubated in seawater containing DCFH‐DA under a range of conditions, and it was also possible to load algae with DCFH‐DA and then follow subsequent DCF production in emersed tissue. DCF formation was linear for at least 2 h in both darkness and light, with the rate of formation increasing with the light level. DCF formation was temperature dependent. It also increased when algae were treated with H 2 O 2 or methyl viologen (paraquat), which disrupts photosystem 1 electron transport and increases O − 2 production. Exogenous catalase reduced in vivo DCF production, presumably by lowering cellular concentrations of H 2 O 2 . Hydrogen peroxide was released into the seawater by illuminated algae resulting in external dye conversion to DCF. However, this does not interfere with in vivo measurement of DCF by loaded, washed algae because DCF leakage appeared to be negligible. Internal DCF did not affect photosynthetic oxygen production relative to untreated controls. Overall, our data suggest that DCFH‐DA is a potentially very useful probe for studying active oxygen metabolism in seaweeds subjected to environmental stresses.