Table 1.

Group settings and conditions for treatment of G59 spores at 4 °C by neomycin in combination with dimethyl sulfoxide (DMSO) to select drug-resistant mutants ^a.

Group	DMSO% (v/v)	Neomycin (mg/mL)	DMSO% Tested on G59 Strain	Treatment Times (Day)
I	20%	2.0	Previously in [13]	1–60
II	33%	3.3	Newly in present study	1–60
III	50%	5.0	Previously in [13]	1–60
IV	67%	6.7	Newly in present study	1–60
V	100%	10.0	Newly in present study	1–60

^a Fresh DMSO was used in all experiments and the used neomycin concentration was restricted up to 10 mg/mL by its solubility in 100% fresh DMSO. Spore suspensions were monitored by the optical density (OD) of 0.35 at 600 nm to keep the same spore density.