Fig. 4: OMVs are involved in the extracellular secretion of membrane-bound CcThi1 and its homolog from the model strain M. xanthus DK1622.
a, b Determination of the growth inhibition ability (a) and thiaminase I activity (b) of OMVs from different myxobacterial strains. The SUP and SUPU fractions were used as control. The growth inhibition assay was performed in 96-well plates. The growth of P6497 was observed using a stereomicroscope (Nikon SMZ-10) (Supplementary Fig. 13), and the colony diameter was statistically analyzed. The thiaminase I activity of SUP, SUPU, and OMVs was determined by measuring the absorbance at 411 nm63 (200 μL components and 200 μL reaction buffer at 37 °C for 1 h). The data represent the means ± SEM (n = 3 biological independent replicates). c, d Western blot analysis of CcThi1 and its homolog in the membrane fraction, OMVs (c), SUP, and SUPU (d) using the anti-CcThi1 antibody. e, f Co-culture assay of Myxococcus strains with P6497 on 10% V8 agar plates. DK1622 and its derivative strains (5 μL, 107 cells/mL) were inoculated next to colonies of P6497. The growth of P6497 was observed after 7 d, and the colony diameter was measured. CL1003, ΔMAXN_4523; CL1004, ΔMXAN_4523::ccthi1, Kanr; CL1005, ΔMXAN_4523::MXAN_4523, Kanr. The data represent the means ± SEM (n = 3 biological independent replicates). Means within columns followed by different letters are significantly different in (a, b, e, f) (p < 0.05, one-way ANOVA, Duncan’s multiple range test). ns represents the non-significant difference in (b). Source data are provided as a Source Data file.
