Single-cell analysis of paralytic shellfish toxins in Alexandrium tamarense by HPLC with post-column fluorescent derivatization

• We developed a method for analyzing the C-toxin content in single Alexandrium tamarense cells.
• With this HPLC-FL method, we could measure 1 fmol of C2 with S/N = 2.
• Clonal heterogeneity within the toxic strain ranged from <1 fmol to 700 fmol cell−1.
• This is the first to demonstrate definitively that PSP content varies on a cell-by-cell basis.

We developed a methodology for analyzing the C-toxin (C2) content in single Alexandrium tamarense cells; this method was based on high performance liquid chromatography (HPLC). C2 is the main paralytic shellfish toxin (PST) detected in a clonal culture of A. tamarense, which is a common causative organism in cases of paralytic shellfish poisoning in Japan. This HPLC method employs post-column fluorescent derivatization (FL). Mobile phase, column size, flow rate, reagent concentrations, and lamp type for the fluorescent detector were all optimized for the detection of C2. With this improved methodology, we could measure 1 fmol of C2 with a signal to noise ratio (S/N) = 2. Clonal heterogeneity within the toxic strain, which was maintained for 13 years after re-isolation from the original clonal culture, ranged from <1 fmol to 700 fmol cell−1. This report is the first to demonstrate definitively that PST content varies on a cell-by-cell basis in a clonal culture of a dinoflagellate that causes paralytic shellfish poisoning.

Figure optionsDownload high-quality image (128 K)Download as PowerPoint slide