hasleana sp. nov. and P. fryxelliana sp. nov., are described RG7204 based on morphological and molecular data. In all phylogenetic analyses, P. hasleana appeared as sister taxa to a clade comprising P. calliantha and P. mannii, whereas the position
of P. fryxelliana was more uncertain. In the phylogenies of ITS, P. fryxelliana appeared to be most closely related to P. cf. turgidula. Morphologically, P. hasleana differed from most other species of the complex because of a lower density of fibulae, whereas P. fryxelliana had fewer sectors in the poroids and a higher poroid density than most of the other species. P. hasleana did not produce detectable levels of DA; P. fryxelliana was unfortunately not tested. In P. cuspidata, production of DA in offspring cultures varied from higher than the parent cultures to undetectable. “
“Following the identification of the first toxic isolate of Dinophysis acuminata from the northwestern Atlantic, we conducted detailed investigations into the morphology, phylogeny, physiology, and toxigenicity
of three isolates from three sites within the northeastern U.S./Canada region: Eel Pond and Martha’s Vineyard, Massachusetts, and the Bay of Fundy. Another isolate, collected from the Gulf of Mexico, was grown under the same light, temperature, and prey conditions for comparison. Despite observed phenotypic Selleckchem BEZ235 heterogeneity, morphometrics and molecular evidence classified the three northwestern Atlantic isolates as D. acuminata Claparède & Lachmann, whereas the isolate from the Gulf of Mexico was morphologically identified as D. cf. ovum. Physiological and toxin analyses supported these classifications, with the three northwestern Atlantic isolates being more similar to each other with respect to growth rate, toxin profile, and diarrhetic shellfish poisoning (DSP) toxin content (okadaic acid + dinophysistoxin 1/cell) than they were to the isolate from the Gulf of Mexico, which had toxin profiles similar to those published for D. cf. ovum F. Schütt. The DSP toxin content, 0.01–1.8 pg okadaic acid (OA) + dinophysistoxin (DTX1) per Sorafenib price cell, of
the three northwestern Atlantic isolates was low relative to other D. acuminata strains from elsewhere in the world, consistent with the relative scarcity of shellfish harvesting closures due to DSP toxins in the northeastern U.S. and Canada. If this pattern is repeated with the analyses of more geographically and temporally dispersed isolates from the region, it would appear that the risk of significant DSP toxin outbreaks in the northwestern Atlantic is low to moderate. Finally, the morphological, physiological, and toxicological variability within D. acuminata may reflect spatial (and/or temporal) population structure, and suggests that sub-specific resolution may be helpful in characterizing bloom dynamics and predicting toxicity.