Phenotypical variation in a toxic strain of the phytoplankter, Cylindrospermopsis raciborskii (nostocales, cyanophyceae) during batch culture
Version of Record online: 15 NOV 2001
Copyright © 2001 John Wiley & Sons, Inc.
Special Issue: 5th International Conference on Toxic Cyanobacteria
Volume 16, Issue 6, pages 460–467, 2001
How to Cite
Hawkins, P. R., Putt, E., Falconer, I. and Humpage, A. (2001), Phenotypical variation in a toxic strain of the phytoplankter, Cylindrospermopsis raciborskii (nostocales, cyanophyceae) during batch culture. Environ. Toxicol., 16: 460–467. doi: 10.1002/tox.10005
- Issue online: 15 NOV 2001
- Version of Record online: 15 NOV 2001
- Manuscript Revised: 24 AUG 2001
- Manuscript Received: 16 JUL 2001
- Co-operative Research Centre for Water Quality and Treatment
- Sydney Water Corporation
- batch culture;
- Cylindrospermopsis raciborskii;
A nonaxenic strain of Cylindrospermopsis raciborskii Woloszynska (AWT 205) was grown in batch culture, with and without nitrate as the primary N source. Rapid log-phase growth with nitrate was 1.0 doubling/day versus 0.3 doubling/day without nitrate. Cylindrospermopsin (CYN) production was measured by HPLC. The rate of intracellular CYN production matched cell division rate for both the diazotrophies at cell densities less than 107 cell/ml. At cell density >107 cell/ml, additional resource limitation in batch culture slowed log-phase growth to 0.04 division/day and cell division and CYN production decoupled. Intracellular CYN concentration increased at a rate of 0.08 doubling/day, twice the cell division rate.
Extracellular CYN as a proportion of the total CYN increased from 20% during the rapid growth phase, to 50% during the slow growth phase. The total CYN yield from cultures grown out to stationary phase (55 days) exceeded 2 mg CYN/l.
C. raciborskii cells in log-phase growth, exposed to 1 ppm copper (as copper sulphate), lysed within 24 hours. After copper treatment, all CYN was in the filterable fraction. These findings imply that in naturally occurring blooms of C. raciborskii, the movement of intracellular CYN into solution will be the greatest during stationary phase, when intracellular concentrations are highest and cell lysis is more frequent. The application of algicides that promote cell lysis will exacerbate this effect. © 2001 John Wiley & Sons, Inc. Environ Toxicol 16: 460–467, 2001