Characterization of paralytic shellfish toxins from Lyngbya wollei dominated mats collected from two Florida springs

Abstract

Lyngbya wollei, a commonly observed cyanobacterium in Florida's spring fed systems, is considered a nuisance organism due to its formation of large benthic and floating mats. Standing crops and mats of Lyngbya from two Florida springs, Silver Glen Springs (Ocala National Forest) and Blue Hole Spring (Ichetucknee Springs State Park), were sampled and characterized via microscopy. A near full-length 16S rRNA gene sequence recovered from genomic DNA preparation of a filament collected from Silver Glen Natural Well was 99% identical to another L. wollei sequence. Paralytic shellfish toxin (PST) biosynthesis genes sxtA and sxtG were also detected in the filament DNA and were 97% and 98% identical in sequence, respectively, to those of L. wollei. PSTs were characterized utilizing High Performance Liquid Chromatography (HPLC) coupled with Mass Spectrometry (MS). Analysis of extracted algal material with LC/MS/MS verified that PSTs decarbamoylgonyautoxin 2&3 (dcGTX2&3) and decarbamoylsaxitoxin (dcSTX) were present in L. wollei mats in Florida springs and provided evidence supporting the presence of all L. wollei toxins (LWT 1-6). Levels of quantifiable toxins (dcGTX2&3 & dcSTX) ranged from 19 to 73μg STX-eq (g dry weight)−1. Although L. wollei toxins 1–6 could not be quantified due to a lack of available standards, their presence indicates samples may be higher in toxicity. This is the first detailed study confirming PST presence in L. wollei dominated mats in Florida spring systems.