Nitrogen gas

PLTX standard (from Palythoa tuberculosa) was purchased from Wako Chemicals GmbH (Germany). For quantitative analysis, concentrations of the target compounds (isoPLTX and OVTX -a to -g analogues) were determined as their respective PLTX equivalents. The stock standard solution (100 µg mL⁻¹) was individually prepared by weight in MeOH:H₂O (80:20, v/v) in a precision balance (Mettler Toledo AG425, Columbus, OH, US). For quantification, calibration solutions of PLTX were prepared from the stock standard solution at concentrations ranging from 0.005 to 5 µg mL⁻¹ in MeOH:H₂O (80:20, v/v). All standard solution aliquots were stored at −20 °C until use. LC–MS grade (>99%) water and organic solvents (acetonitrile and formic acid) were from Sigma-Aldrich (Steinheim, Germany). The mobile phases were filtered through 0.22 µm Nylon membrane filters (Whatman, Clifton, NJ, USA) before use. Nitrogen gas (99.95%, from Linde, Barcelona, Spain) was used as sheath gas and auxiliary gas in the ionization source. The 25 mm GF/F glass fiber filters were purchased from Whatman (Clifton, NJ, USA). The Lugol solution used to fix culture samples for Ostreopsis cell counts was prepared following Andersen and Throndsen (2004), with potassium iodide (KI) and iodine (I₂) from Merck (Darmstadt, Germany) [77 ].

The key materials used for the studies were acquired from the following sources: 4-pentyl-1-ol, sodium ascorbate, triethylamine and sodium dodecyl sulfate (SDS) were purchased from Sigma-Aldrich (Darmstadt, Germany). 4-dimethylaminopyridine (98%) was acquired from Fluka (Buchs, Switzerland). Buffer SpotQC was obtained from Integrated DNA Technologies (Coralville, IA, USA) and saline-sodium citrate (SSC) was from Ambion (Austin, TX, USA). A total of 4% Trilux, from Analab (Warsaw, Poland), was used as a detergent. All organic solvents for glass slides preparation were purchased from Avantor Performance Materials Poland S.A. (formerly POCH, Gliwice, Poland) and used as purchased. Nitrogen gas (99.999%) was acquired from Linde (Munich, Germany). Redistilled water was obtained from a glass water distiller system type 2304 from GFL Gesellschaft für Labortechnik GmbH (Berlin, Germany). Glass slides were the standard 26 × 76 × 1 mm soda lime microscope slides supplied by Knittel Glass (Braunschweig, Germany). Silica gel chromatography was conducted with the use of the 70–230 mesh silica gel from Merck (Darmstadt, Germany). Phosphoramidite reagents for the DNA synthesis were purchased from Glen Research (Sterling, VA, USA), fluorophore CPG with Quasar 670 from Biosearch Technologies (Novato, CA, USA) and solvents from Carl Roth GmbH (Karlsruhe, Germany).