Posted by Stephanie A. Smith, Ph.D., on Thu, April 9, 2015
I had predicted in my last HAB Five blog that by this time I would be reveling in my winnings from the Beagle March Madness bracket. But alas, it was not to be. Rather, and not disappointingly, I’ve been reveling in a recent surge of orders for the toxin cylindrospermopsin. This is a great sign that research on this toxin might be picking up. Like the more widely recognized microcystin, cylindrospermopsin is a liver toxin, but it is an alkaloid rather than a peptide toxin, and it kills liver cells by a different mechanism than microcystin does. Is it more or less toxic than microcystin, you ask? Well, there hasn’t been a good study to provide a clear answer to that, but as the fun facts below demonstrate, such studies are sorely needed:
- Cylindrospermopsin is now known to have been the cause of “Palm Island Mystery Disease,” where a 1979 outbreak of hepatoenteritis in northern Queensland, Australia appeared to be attributable to the cyanobacterium Cylindrospermopsis raciborskii. Over 140 people, almost all children, were hospitalized!
- We can also thank the folks down under for the memorable moniker “Barcoo spews,” a gastric ailment recognized in the Australian Outback as early as the late 1800s, and now suspected to be a mild form of cylindrospermopsin intoxication.
- The toxin is also widespread in the U.S., confirmed in states from Florida to Oregon. One of the worst U.S. blooms was in 2005 at Illinois’ Otter Lake, where the cell counts for C. raciborskii forced local authorities to post that people ought-er not swim there! (Hey, I’m tryin’).
- Quite surprisingly, after the Otter Lake bloom, a subsequent analysis showed that there was no cylindrospermposin in water samples, even in a sample that had exceedingly high counts of C. raciborskii. Non-toxin-producing blooms of C. raciborskii are not uncommon, but note that they can be harmful in other ways, such as leading to low-oxygen conditions in a lake that might cause fish to die.
- Cylindrospermopsin was not isolated and characterized from cultures of C. raciborskii until 1992 by Ohtani, Moore, and Runnegar (J. Am. Chem. Soc. 114:7941).
I want to acknowledge fellow Beagle Sarah Dreher for helping me to track down interesting facts about cylindrospermopsin. Next time, I’ll talk about one of the nastier members of the HAB Five, the potent neurotoxin saxitoxin.