Magnetic Properties of Magnetotactic

Some magnetic properties of wild strain soil and intestinal as well as cultative in laboratory conditions of Desulfovibrio desulfuricans bacteria were studied by means of the electron paramagnetic resonance spectroscopy (EPR) and torque method. The main wide signal in the EPR spectrum corresponds to the low spin (S=1/2) Fe3+ ion. The broadening of EPR lines revealed strong dipole-dipole interaction and possible misorientation of magnetic spins of magnetosomes. The sharp resonance line derived from the free radicals enclosed in the bacteria was also observed. More paramagnetic centra were found in the bacteria cultative in laboratory conditions than in the wild strains of Desulfovibrio desulfuricans bacteria. The torque curves had a sinusoidal shape characteristic of uniaxial anisotropy and increased almost linearly with magnetic field. The effective anisotropy coefficients for wild strains were several times larger than those grown in laboratory conditions