Fig 1.

Csn-B and its derivatives inhibited the secretion of SPI-1 effectors and invasion of S. enterica serovar Typhimurium into HeLa cells. (A) Chemical structures of Csn-B derivatives and positive control INP0403. (B) Compounds inhibited secretion of SPI-1 effector proteins. SipA/B/C/D, SPI-1 effector proteins; FliC, flagellar filament protein; M, marker; C, DMSO control. (C) Compounds secocurvularin, C5, Csn-B, and INP0403 inhibited the invasion of S. enterica serovar Typhimurium into HeLa cells. The values represent percentages of invading bacteria as related to the initial input, and error bars indicate standard deviations from the means. The levels of statistical significance is indicated as follows: *, P ≤ 0.05; ***, P ≤ 0.001. The P value was calculated by comparing the value for the DMSO negative control.