Controlled cultivation of Alexandrium minutum and [P] orthophosphate cell labeling towards surface adhesion tests

We describe a protocol for preparing cultures of the PSP (paralytic shellfish poisoning) dinoflagellate Alexandrium minutum, towards subsequent studies of cell adhesion onto artificial substrates. First, phenotypic uniformity of the strain used and reproducibility of the standard growth profile are obtained by optimising key parameters. Batches of A. minutum at mid-exponential proliferation phase are radiolabeled with ³³P-containing medium in order to later quantify cell adhesion. A mortality corrective index is applied to the latter, using the vital fluorochrome acridine orange, i.e. dead cells show no nuclear incorporation under epifluorescence microscopy.