Light-dependent oxygen uptake by non-living, chlorophyll-containing particles obtained from oceanic environments

摘要

Chlorophyll-containing, non-living particles obtained from oceanic environments showed a light-dependent oxygen uptake reaction. Activity was found in marine samples rich in diatom cells and cell fragments, though particles originating from dinoflagellates showed only insignificant activity. The same reaction was seen in sonic-disrupted and washed cell fragments of culturedPhaeodactylum tricomutum.The reaction did not require extra electron donors or electron carriers, even in particles washed thoroughly with buffer. Add-back of the soluble fraction had no effect. The action spectrum of the reaction indicated that only light absorbed by chlorophylls was effective though the sample also contained carotenoids.Based on the data obtained we inferred that the O2uptake reaction is the same as that caused by the action of isolated chlorophylls and, that a water-insoluble compound(s) contained in the samples served as electron donor. A possible contribution of this reaction to the O2economy in oceanic environments is discussed.