Figure 2.

Estimated maitotoxin equivalents (µg MTX eq) in the LH-20-fractionated MSFs of G. excentricus strains VGO791 and VGO792 measured using the N2a cytotoxicity assay. (a) MTX eq of the individual 2.5 mL-fractions for G. excentricus VGO791 (2.20 million cells extracted in original MSF, approximately half of which was loaded on the LH-20 column). (b) MTX eq of the individual 1 mL-fractions for G. excentricus VGO792 (2.16 million cells extracted in original MSF, approximately half of which was loaded on the LH-20 column). The x-axis is expressed as the total elution volume (mL) that has passed through the LH-20 column when each fraction was collected. Error bars represent assay variability (standard deviation, SD) measured by running extracts in three separate assays. In each assay, three separate wells were used for assaying each fraction. Cytotoxicity was observed only in LH-20 fractions within an elution volume (V_e) range of (a) V_e = 12.5–27.5 mL and (b) V_e = 13.0–26.0 mL. Asterisks (*) in (b) indicate detection of non-quantifiable cytotoxicity in fractions with V_e = 23.0–26.0 mL. Fractions corresponding to V_e < 10.0 mL and V_e > 30.0 mL are not shown because no cytotoxicity was observed in those fractions.