Magnetotactic bacteria from freshwater lakes in Georgia.

Several species of magnetotactic bacteria were discovered in the lakes and ponds of Georgia. Electron microscopic analysis of the bacteria showed a great variety of microbial forms as well as magnetosome arrangements. Pyramidal, cubical or hexagonal magnetic grains could be seen in different species of bacteria. The linear organization of magnetic particles was prevailing, although gathered magnetosomes were also seen. Magnetometric measurement of magnetic particles obtained from coccoid bacteria was performed. Remnent acquisition curves, as well as thermomagenetic curves of investigated material showed that the magnetosomes under study contained pure single-domain magnetite.