Mechanistic insight into the effect of BT‐benzo‐29 on the Z‐ring in Bacillus subtilis

Abstract

The assembly and disassembly of FtsZ play an essential role in bacterial cell division. Using single‐cell imaging, we report that short exposure to BT‐benzo‐29 inhibits Z‐ring formation in live Bacillus subtilis cells. Fluorescence recovery after photobleaching of the Z‐ring in live bacteria demonstrated that BT‐benzo‐29 strongly suppressed the assembly dynamics of FtsZ in the Z‐ring. Furthermore, B. subtilis cells expressing V275A‐FtsZ resisted the antibacterial activity of BT‐benzo‐29 providing evidence that BT‐benzo‐29 inhibits bacterial proliferation by targeting FtsZ. In addition, a brief (8 min) exposure of BT‐benzo‐29 destroyed the Z‐ring without perturbing the localization of a late cell division protein, DivIVA, the nucleoid segregation, and membrane permeability. BT‐benzo‐29, when used in combination with vancomycin and polymyxin B (PMB), produced a much stronger inhibitory effect on Bacillus subtilis and Escherichia coli cells, respectively. The combination index of BT‐benzo‐29 with vancomycin and PMB was determined to be <1, suggesting that BT‐benzo‐29 exhibits synergistic inhibitory effects on bacterial proliferation when used along with these antibiotics.

Antibacterial activity of a new monocarbonyl analog of curcumin MAC 4 is associated with divisome disruption

“…In order to investigate whether cell division is a target for the new curcumin analog, we evaluated the effects of MAC 4 on the divisome using B. subtilis strain expressing FtsZ-GFP, which labels the bacterial divisome. B. subtilis was selected because this species is commonly used in studies on the antibacterial action mode of new agents [65,66] and its division process has been extensively explored [6]. B. subtilis was treated with MAC 4 at ½MIC (73.6 µmol/L) for up to 30 min and analyzed under the microscope.…”

Recent progress of bacterial FtsZ inhibitors with a focus on peptides

“…Ray et al evaluated the effects of benzimidazole derivative BT‐Benzo‐29 on FtsZ assembly in B. subtilis cells and found that it had potent antibacterial activity against B. subtilis [121]. BT‐Benzo‐29 could bind to the C‐terminal T7 loop of FtsZ and inhibited GTPase activity and FtsZ assembly in B. subtilis ; it weakly bound to mammalian tubulin and did not disrupt the membrane of human red blood cells, indicating its strong antibacterial potential with low toxicity against eukaryotes [122]. Kunal et al found that an 8‐min exposure to BT‐benzo‐29 could inhibit Z‐ring formation in B. subtilis cells by suppressing the assembly dynamics of FtsZ, indicating that BT‐benzo‐29 inhibits bacterial proliferation by targeting FtsZ [122].…”

“…Recently, new numerous active compounds such as UCM05, UCM44, and UCM53 have been screened by docking into FtsZ GTP‐binding site of B. subtilis . These FtsZ inhibitors bound to FtsZ molecules by replacing GTP, impaired Z‐ring formation, delocalized FtsZ into multiple foci, and inhibited cell division in B. subtilis , MDR S. aureus, and E. faecalis , resulting in long undivided cells [122,123]. Most compounds display potent activity against Gram‐positive bacteria, including MRSA (MICs < 7 μM) and low cytotoxicity toward mammalian cells, indicating the potential of promising clinical candidates in the future [12,123].…”