Figure 4
Effect of ND8008 on MRSA biofilm formation.
(a) Crystal violet staining for biofilm quantity. MRSA biofilms were formed on 24-well microtitre plates and then washed and incubated for 24 h and 48 h with 10/25/50 μM ND8008, 50 μM Dex, 50 μM ISMN or 50 μM Dex + ISMN. CLSM images of MRSA with 50 μM ND8008, 50 μM Dex, 50 μM ISMN or 50 μM Dex + ISMN treatment. For confocal microscopy, MRSA biofilms were formed on plastic coverslips and then incubated for 24 h with 50 μM ND8008, Dex, ISMN or Dex + ISMN. The coverslips were then washed and analysed. The biofilms were stained with SYTO9 (green) for live cells and PI (red) for dead cells and extracellular DNA. (b–f) The three-dimensional structural images of biofilms treated with 50 μM ND8008 (b), 50 μM Dex (c), ISMN (d) or 50 μM Dex + ISMN (e). The same volume of ethanol was added to the control treatments in place of the drugs (f). (g) In the three-dimensional structural images of biofilms, the viable cells exhibited green fluorescence whereas, dead cells exhibited red fluorescence. The percentage of live bacteria relative to the total bacterial counts (shown in brackets) were calculated by using the ImageJ software. Error bars indicate the standard deviations of 4 measurements. ***P < 0.001 versus the control. *P < 0.05 versus the control.
