Interaction of the calcium ionophore A.23187 (Calcimycin) with Bacillus cereus and Escherichia coli

Abstract

Ionophores isolated from bacterial strains, and especially A.23187, are efficient antibiotics against Gram‐positive bacteria and devoid of activity on Gram‐negative species. This difference in activity was attributed to the outer membrane of Gramnegative bacteria which is presumably impermeable to these very hydrophobic compounds. In this context, the partition of the calcium ionophore A.23187 between bacteria and the medium was studied on Escherichia coli (Gram‐negative) and Bacillus cereus (Gram‐positive) using, on the one hand, fluorimetric measurements and, on the other hand, radioautographic analysis of bacteria incubated with the [3H]‐labelled ionophore. Although the first method did not give a definitive answer, the second one clearly showed that the tritiated metabolite was only incorporated into B. cereus.

Polyether ionophores: broad-spectrum and promising biologically active molecules for the control of drug-resistant bacteria and parasites

“…All these findings were later confirmed by a second group [ 90 ]. Laidlomycin (29) was also reported to induce a dose-dependent inhibition of HIV replication. The MOA of laidlomycin (29) was proposed to be via inhibition of gp120 expression.…”

“…Laidlomycin (29) was also reported to induce a dose-dependent inhibition of HIV replication. The MOA of laidlomycin (29) was proposed to be via inhibition of gp120 expression. Laidlomycin (29) also induced an inhibitory effect on syncithium formation at concentrations as low as 1 μg/ml [ 92 ].…”

“…reports describe the potential of carboxyl ionophores, monensin (2), salinomycin (4), lasalocid (1), nigericin (5), dianemycin (20), alborixin (11), kijimicin (39), SF2361 (43), SF2324 (44), SF2487 (45) and laidomycin (29) as anti-HIV agents [ 86 -91 ].…”

“…Kawada et al [ 42 ] evaluated the effects of several carboxyl ionophores on colchicine resistance in human carcinoma MDR KB-C410 [ 42 ]; these compounds were inostamycin (24), lysocellin (15), laidlomycin (29), monensin (2), dianemycin (20), leuseramycin (26), nigericin (5), lonomycin A&C (17,22), carriomycin (8), deoxy-salinomycin, antibiotic 6016 (23), SF2324 (44), SF2361 (43) and SF2487 (45). It was discovered that the cancer cells responded better to colchicine when some polyethers were added simultaneously.…”

Structures and Properties of Naturally Occurring Polyether Antibiotics

“…This difference in activity is attributed to the outer membrane of Gram-negative bacteria which is presumably impermeable to these highly hydrophobic compounds [26]. …”