MICROBIOLOGY ASTROBIOLOGY A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site magnetotactic bacteria The magnetotatic bacterium Magnetospirillum magnetotacticum. Image credit: R. Frankel Bacteria that effectively have internal compasses and are able to orient themselves with respect to a magnetic field. Magnetotactic bacteria (MTB) orient and migrate along the geomagnetic field towards favorable habitats, a behavior known as magnetotaxis. They were first reported in 1975 by microbiologist Richard P. Blakemore. Subsequent studies have shown that MTB are a morphologically diverse group of aquatic microorganisms that live in both freshwater and marine environments ranging from aerobic to anoxic. All MTB contain magnetosomes, which are nanometer-sized, magnetic, mineral crystals enclosed in a membrane. In most cases the magnetosomes are arranged in a chain or chains, apparently fixed within the cell adjacent to the plasma membrane. In many MTB strains, the magnetosome crystals are magnetite, characterized by a narrow size distribution and uniform, species-specific, crystal habits. In MTB from marine, sulfidic environments, the magnetosome crystals are the iron-sulfide mineral greigite (Fe3S4), which is isostructural with magnetite and is also ferrimagnetically ordered at room temperature. Related categories    • MICROBIOLOGY    • ASTROBIOLOGY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP