Use of model micro-organism to study cytostatics-membrane interactions

A strain of Bacillus stearothermophilus was used as a model system to elucidate the interaction of tamoxifen with the cell membrane. This drug inhibits bacterial growth in a concentration-dependent manner. The inhibition increases at suboptimal and supraoptimal temperatures and is attenuated by the addition of Ca(2+) to the growth medium. Opposed physical alterations on bacterial membranes were observed when tamoxifen was added to the growth medium (increase in structural order) or directly in liposome preparations (decrease in structural order).