Magnetic modulation of bacterial polymer deposition on solid surfaces

Microscope slides dipped vertically into cultures or oral bacterium Streptococcus mutans, for 24 h, accumulated over 100% more bacterial polysaccharide on the side facing North, as determined chemically. Inversion of the magnetic field by 180° caused a similar inversion of the preferential accumulation (P.A.). The P.A. occurred on dia-, para-, and ferromagneticslides. P.A. is a physiologic response linked to adherence on vertical surfaces against gravity.