Hardware/Instruments: Microcentrifuge (such as Sorvall™ Legend™ Micro 21), L-80 Preparative Ultracentrifuge (Beckman Coulter) or equivalent, Type 70.1 rotor (Beckman Coulter, ref 342184, k-factor 42), SW60 rotor (Beckman Coulter, ref 335650, k-factor 31), polycarbonate bottles (Beckman Coulter, ref 355603), polyallomer conical tubes