Morphological descriptions using light and scanning electron microscopy and molecular characterization of two Prorocentrum lima strains (UNR-01 and UNR-09) isolated from Armação dos Búzios, Rio de Janeiro, Brazil are provided. Okadaic acid (OA), dinophysistoxin-1 (DTX1) and DTX2 production by strain UNR-01 was investigated using liquid chromatography with mass spectrometry. Toxins were extracted from heat-treated (boiled) and non-boiled cell pellets to obtain respective quantities of free and total OA and DTX1. Growth parameters (growth rate and mean generation time) were determined for strain UNR-01. Prorocentrum lima cells were oblong-to-ovate in shape, broad in the middle region, and narrow at the anterior end. The periflagellar area was triangular, set into a V-shaped depression and was composed of eight periflagellar platelets of different sizes. The morphology fits well the characterization of the species isolated from elsewhere. Phylogenetic analysis based on internal transcribed spacer - ITS - and D1-D3 large subunit - LSU - of ribosomal RNA gene sequences revealed that both strains were identical and closely related to P. lima isolates from the Caribbean Sea and USA. The growth rate of strain UNR-01 was 0.24divday-1. OA concentrations were on average 15.2 and 38.5pg[OA]cell-1 for heat-treated and non-treated cells respectively, while DTX1 mean concentration was 0.5pg[DTX1]cell-1 for both heat-treated and non-treated cells. DTX2 was not detected. To date, these are the first strains of P. lima from the south Atlantic that have been characterized.
Keywords: Dinophysistoxin; Epibenthic dinoflagellate; Liquid chromatography mass spectrometry; Molecular phylogeny; Okadaic acid.
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