Fig. 3.
Mass spectrometry analysis of Streptomyces sioyaensis culture extract and antibacterial activity of S. actuosus ISP-5337, S. sioyaensis B-5408, and A. acidiphila B-2296 fractionated extracts challenged against Staphylococcus aureus. a) Siomycin extracted from the total ion count at a retention time of 2.96 min. b) Mass spectra under the 2.96 min chromatographic peak at 2.96 min shows the primary doubly charged isomers of siomycin at a m/z of 2 indicated by the 824.7217 Da peak and the parent compound and singly charged at 1648.3644 Da. c-e) MSe data under the 2.96 min chromatographic peak at 2.96 min identified two fragment at m/z of 526.3551, blue cleavage pattern, and m/z of 624.3266, yellow cleavage pattern. f) Fractionation protocol used for elution of compounds by increasing polarity. g) Stacked extracted ion chromatogram extracted at 2.96 min, showing for siomycin that was identified in fraction 8 only. h-j) Growth curve analysis of Staphylococcus aureus survival by O.D.600 measurements at the indicated time interval (minutes) when challenged against fractions derived from Streptomyces actuosus, Streptomyces sioyaensis, and Actinospica acidiphila. Each assay was completed with three biological replicates (n = 3) and the standard deviation was calculated per timepoint.