Phototaxis in Cryptomonas sp. under condition suppressing photosynthesis

Photomovement of Motile Microorganisms

“…Blue light was less effective, while red light above 640 nm was again completely ineffective. Since phototaxis of Cryptomonas was only slightly sensitive to M DCMU, which completely inhibits photosynthetic O2 evolution, correlations between phototactic stimulus perception and photosynthesis can certainly be excluded (Watanabe et al, 1976).…”

Effects of the Timing of Flashes of Light during the Course of Cellular Rotation on Phototactic Orientation of Individual Cells of Cryptomonas

“…Each chloroplast which occupies a large volume of the Cryptomonas cell (13) may absorb and attenuate light from directions other than the anterior ventral side ofa cell. The chloroplast may not be the photoreceptor organelle of phototaxis itself, as photosynthetic mechanisms do not participate directly in phototaxis of Cryptomonas (25). The paraflagellar swelling, which exists in the opening, appears to be the photoreceptive site in Euglena (3,4,14,15).…”

Effects of Solar Radiation on Photoorientation, Motility and Pigmentation in a Freshwater Cryptomonas

“…In contrast, the marine Crgptornonas maculata uses a positive phototaxis at fluence rates I 15 W m-' and an even more pronounced negative phototaxis at higher fluence rates . The photoreceptor has not been identified for either species, but an action spectrum has been measured for phototaxis which extends from 400nm to 680nm with a major maximum at about 560 nm which corresponds with the absorption of the main accessory pigment, phycoerythrin, in this species (Watanabe et al, 1976;Watanabe and Furuya, 1982). The photosynthetic machinery does not seem to be involved in this process, since the chlorophylls a and c do not contribute to orientation and, in addition, the inhibitors of the photosynthetic electron transport chain, DCMU and DBMIB, do not impair phototaxis .…”