Posted by Stephanie A. Smith, Ph.D., on Wed, June 18, 2014 @ 12:00 PM
LA LA Land may be a state of mind; one you frequent on weekends or where you think your teenager resides permanently. Or…maybe it’s a Land where one finds a lot of LA? A lake or reservoir that has Microcystin-LA in it…well, that’s not a happy place like LA LA Land. But it’s a place that we’ve been stumbling upon more often than we ever expected.
Beagle Bioproducts has traveled around the country collecting harmful algal bloom (HAB) biomass from freshwater blooms for the past two years. We use this raw biomass as a feedstock for purification of cyanobacterial toxins, especially microcystins, which we sell to the community of scientists that study HABs and HAB toxins.
There are suspected to be over 80 “congeners” of microcystin toxins, which all have a similar 7-peptide sequence that can differ at two positions. The congeners are identified with the call letters for the amino acids at those positions: Microcystin-LR is leucine/arginine, LA is leucine/alanine, RR is arginine/arginine, and so forth. If you’re not a scientist, think of these as different “flavors” of microcystin. LR has long held the title of the most commonly occurring microcystin congener globally (vanilla?).
At Beagle, we’re starting to believe that microcystin-LR may have been unseated as the most popular flavor, or that LR may not be as dominant as previously thought. Of the 10 or so collections we have done, as well as in samples we have assessed where we didn’t collect, only one site has had LR as the dominant microcystin congener. In fact, we far more frequently find RR, and a recent batch we processed was dominated by LA (a pleasant surprise, since this is not easy to come by).
This is an observation, not an analysis, but it might matter because little is really understood about the toxicity of the different microcystin congeners, relative to what is known about microcystin-LR. Further, we suspect that animals and people are exposed to these non-LR microcystins more frequently than has previously been expected. Maybe our observation is heavily biased, since most of Beagle’s microcystin has been collected in the American Midwest. Geographical distribution of the microcystin congeners is another area where not much is known.
So we’re curious what others out there think. Do you believe that LR is the vanilla of the microcystins, or do you think there are a lot more LA LA Lands out there than we know?