Tα1-PAS samples were diluted to 1 mg/mL in endotoxin-free water (Veolia Water Technologies, Celle, Germany), heated to 90 °C for 5 min, and, after cooling down to RT, bacterial endotoxins were quantified using an Endosafe® system (Charles River Laboratories, Wilmington, MA, USA) with an FDA-licensed PTS™ cartridge (10–0.1 EU/mL sensitivity).