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Mar Drugs

Title:		Preliminary characterization of extracellular allelochemicals of the toxic marine dinoflagellate Alexandrium tamarense using a Rhodomonas salina bioassay
Author(s):		Ma H; Krock B; Tillmann U; Cembella A;
Address:		"Alfred Wegener Institute for Polar and Maine Research, Am Handelshafen 12, Bremerhaven, Germany. Haiyan.Ma@awi.de"
Journal Title:		Mar Drugs
Year:		2009
Volume:		20091102
Issue:		4
Page Number:		497 - 522
DOI:		10.3390/md7040497
ISSN/ISBN:		1660-3397 (Electronic) 1660-3397 (Linking)
Abstract:		"Members of the marine dinoflagellate genus Alexandrium are known to exude allelochemicals, unrelated to well-known neurotoxins (PSP-toxins, spirolides), with negative effects on other phytoplankton and marine grazers. Physico/chemical characterization of extracellular lytic compounds of A. tamarense, quantified by Rhodomonas salina bioassay, showed that the lytic activity, and hence presumably the compounds were stable over wide ranges of temperatures and pH and were refractory to bacterial degradation. Two distinct lytic fractions were collected by reversed-phase solid-phase extraction. The more hydrophilic fraction accounted for about 2% of the whole lytic activity of the A. tamarense culture supernatant, while the less hydrophilic one accounted for about 98% of activity. Although temporal stability of the compounds is high, substantial losses were evident during purification. Lytic activity was best removed from aqueous phase with chloroform-methanol (3:1). A 'pseudo-loss' of lytic activity in undisturbed and low-concentrated samples and high activity of an emulsion between aqueous and n-hexane phase after liquid-liquid partition are strong evidence for the presence of amphipathic compounds. Lytic activity in the early fraction of gel permeation chromatography and lack of activity after 5 kD ultrafiltration indicate that the lytic agents form large aggregates or macromolecular complexes"
Keywords:		Animals Biological Assay Dinoflagellida/*chemistry Humans Marine Toxins/*chemistry Neurotoxins/chemistry Pheromones/*chemistry Alexandrium tamarense allelochemicals cell lysis extracellular compound;
Notes:		"MedlineMa, Haiyan Krock, Bernd Tillmann, Urban Cembella, Allan eng Research Support, Non-U.S. Gov't Switzerland 2010/01/26 Mar Drugs. 2009 Nov 2; 7(4):497-522. doi: 10.3390/md7040497"