UV-excited blue autofluorescence of Pseudo-nitzschia multiseries (Bacillariophyceae)

A flow cytometer coupled to a scanning monochromator and a fluorescence microscope were used to characterize the fluorescence spectrum of Pseudo-nitzschia multiseries (Haste) Haste, a pennate diatom that produces the neurotoxin domoic acid, a lethal amnesic. In this research, we characterize the fluorescence spectrum of P multiseries in vivo over the wavelength range of 360 to 850 nm and show that this diatom autofluoresces blue when excited with UV light (350-365 nm). The autofluorescence characterization of Pseudo-nitzschia may provide new methods for rapid in situ monitoring of diatom populations and reiterates the usefulness of flow cytometry in the analysis and study of marine phytoplankton.