Figure 7.

Morphological bacterial changes caused by conventional antibiotics in B. subtilis. Morphological changes of B. subtilis caused by conventional antibiotics were studied as explained in the Materials and Methods section. B. subtilis was incubated for 2 h at 37 °C in aerobic conditions with 4 × MIC of conventional antibiotics with known bacterial target. Control (A–C) was bacteria with no antibiotics added. Antibiotics used were: amoxicillin ((D–F), inhibiting cell wall synthesis), gemifloxacin ((G–I), inhibiting DNA synthesis), fifampicin ((J–L), inhibiting RNA synthesis) and tetracycline ((M–O), inhibiting protein synthesis). Images shown are representative of overall observed effects and correspond to bacterial membrane stained with FM4-64FX (red signal) (A,D,G,J,M), bacterial DNA stained with DAPI (B,E,H,K,N) and merged membrane and DNA signals (C,F,I,L,M,O). The white scale bar on the bottom right corner corresponds to 4 µm.