Characterization and quantification of karlotoxins by liquid chromatography–mass spectrometry

A bloom of Karlodinium australe (Gymnodiniales, Dinophyceae) associated with mass mortality of cage-cultured fishes in West Johor Strait, Malaysia

“…It is well known that some Karlodinium species kill fish, but not all species are capable of producing karlotoxins. Among the ten known species, only K. armiger, K. conicum de Salas and K. veneficum were found to be ichthyotoxic (Garcé s et al, 2006;Bachvaroff et al, 2008Bachvaroff et al, , 2009Mooney et al, 2009). The ability of K. australe to produce toxins has not yet been elucidated, but the necropsy evidence of dead fish examined in this study show similarities to those reported in naturally occurring or experimental fish kills due to karlotoxins Kempton et al, 2002).…”

Investigation of the algicidal exudate produced by Shewanella sp. IRI-160 and its effect on dinoflagellates

“…After the filtrate was loaded onto the cartridge it was washed with 12 mL of distilled water followed by increasing concentrations of methanol/water from 0% methanol (v/v) to 100% methanol in 20% increments. A portion of each eluate was analyzed by LC-MS as described in Bachvaroff et al (2008).…”

Isolation of activity and partial characterization of large non-proteinaceous lytic allelochemicals produced by the marine dinoflagellate Alexandrium tamarense

“…The only exception is maitotoxin with a molecular mass of 3422 g mol -1 , the largest non-biopolymer natural product known (Murata et al, 1994). Karlotoxins from the dinoflagellate Karlodinium veneficum (Bachvaroff et al, 2008;Van Wagoner et al, 2008) as well as amphidinols from Amphidium klebsii (Houdai et al, 2004;Houdai et al, 2005) have a similar mass range of about 1300 Da and membrane disruptive properties. These compounds form hairpin structures suggested to be important for the interaction with lipid bilayers of biomembranes.…”

“…The masses of 1291.6 and 1061.6 from the lytic A. tamarense strain fall within this mass range. Moreover these compounds, like karlotoxins, are eluted with 80% methanol from C18 SPE cartridges (Bachvaroff et al, 2008). As a working hypothesis it was reasonable to consider that these two masses may be related to lytic activity and structurally similar to karlotoxins.…”