Our experimental method consists of first separating an INS suspension into a low-density fraction and high-density fraction using density gradient centrifugation (Section 2.1). The low-and high-density fractions are then washed via differential centrifugation to remove density gradient medium from the INSs (Section 2.2). The concentration of INSs in the two isolates are then quantified with the droplet freezing technique (Section 2.3).