A Method for Quantitative Determination of the Number of Magnetosomes in Magnetotactic Bacteria by a Spectrophotometer

A method for quantitative determination of the number of magnetosomes in magnetotactic bacteria (MTB) was developed in this paper. Using a magnetism measuring system that composed of a common laboratory spectrophotometer and an electromagnetic system, the relation between the R_mag of the MTB solution and the magnetic flux density of the applied magnetic field could be measured. The formula to calculate the percentage distribution of the bacteria with different numbers of magnetosomes was deduced in this paper, which depended on the R_mag curve under different magnetic flux densities. The related parameters were obtained by fitting the real measured results. Finally, the distribution of the MTB with different numbers of magnetosomes was detected by the proposed method.