title: Semi-quantitative assay for polyketide prymnesins isolated from Prymnesium parvum (Haptophyta) cultures.
abstract: A fluorometric assay was developed to semi-quantify co-purified polyketide prymnesins-1 and -2 (PPs) from Prymnesium parvum cultures. Evaluations performed throughout the growth cycle of 5 practical salinity unit (PSU) cultures detected relatively 8-10 × more PPs in the culture medium (exotoxins) than in cells (endotoxins). The [exotoxin] remained stable and relatively low until post-log growth, when they increased significantly. However, on a per-cell basis, [exotoxin] declined throughout log phase and subsequently increased dramatically during late- and post-log phases. The [endotoxin] remained stable until late- and post-log phases, when it achieved its highest level before declining sharply. Shaking cultures of strains from Texas, South Carolina and the United Kingdom displayed dramatically different [exotoxin] during post-log decline. Cultures adapted to 30 PSU had significantly lower [exotoxin] over the course of cultivation than those grown at 5 PSU. Phosphate limitation enhanced [exotoxin] on a per-cell basis, especially in late- and post-log cultures. Media containing streptomycin exhibited a ∼20% increase in [exotoxin] in post-log cultures vs. control treatments, but it had only negligible effects on endotoxin levels. Brefeldin A had minimal effects on [exotoxin], suggesting that the presence of PPs in the medium may be largely derived from cell lysis or some other passive means.
authors.affiliation: Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA. Electronic address: laclaire@utexas.edu.
authors.forename: J W
authors.initials: JW
authors.lastname: La Claire
authors.affiliation: Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: S R
authors.initials: SR
authors.lastname: Manning
authors.affiliation: Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Talarski
mesh_terms: D000818:Animals; D001681:Biological Assay; D002478:Cells, Cultured / Q000737:chemistry*; D058087:Haptophyta / Q000737:chemistry*; D008074:Lipoproteins / Q000032:analysis*; D008387:Marine Toxins / Q000032:analysis*; D061065:Polyketides / Q000032:analysis*; D013022:South Carolina; D013781:Texas; D006113:United Kingdom
chemical_list: D008074:Lipoproteins; D008387:Marine Toxins; D061065:Polyketides; C001884:prymnesin
keywords: Chemifluorometric assay; Ichthyotoxins; Polyketides; Prymnesins; Prymnesium parvum; Semi-quantification