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A GROWTH ADVANTAGE FOR MICROCYSTIN PRODUCTION BY MICROCYSTIS PCC7806 UNDER HIGH LIGHT1
Article first published online: 10 OCT 2011
© 2011 Phycological Society of America
Journal of Phycology
Volume 47, Issue 6, pages 1241–1246, December 2011
How to Cite
Phelan, R. R. and Downing, T. G. (2011), A GROWTH ADVANTAGE FOR MICROCYSTIN PRODUCTION BY MICROCYSTIS PCC7806 UNDER HIGH LIGHT. Journal of Phycology, 47: 1241–1246. doi: 10.1111/j.1529-8817.2011.01056.x
Received 26 May 2010. Accepted 31 March 2011.
- Issue published online: 1 DEC 2011
- Article first published online: 10 OCT 2011
- growth advantage;
- Microcystis PCC7806
Batch cultures of both Microcystis PCC7806 and a mcyA− knockout mutant (MT) of PCC7806 were cultured at three different light intensities and five media treatments, so as to vary cellular N:C ratios and concentrations and sampled daily over 5 d for analysis of microcystin concentration, cell numbers, and residual nitrate in the growth medium. A competitive survival advantage was noted at a high-light level (37 μmol photons · m−2 · s−1), where the toxic strain survived while the nontoxic strain became chlorotic. A strong correlation (r2 = 0.91, P < 0.001, N = 22) between microcystin concentration and growth rate was observed at high-light conditions. No advantage was observed at optimal or low-light conditions, and media composition had no significant effect on the relationship between toxicity and survival at high-light conditions. These data suggest a possible role for microcystin in protection against photooxidation.