Genetic Engineering of Single-Domain Magnetic Particles
Annual rept. 1 Mar 1989-2 Feb 1990
SRI INTERNATIONAL MENLO PARK CA MOLECULAR BIOLOGY DEPT
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Magnetotactic bacteria selectively synthesize membrane-bound, nanometer-sized, single-domain magnetic particles known as magnetosomes. Because these bacteria have complex nutritional requirements, only one species, Aquaspirillum magnetotacticum, has been grown in pure culture. This bacterium produces approximately twenty intracellular magnetic particles per cell of single-domain size. To synthesize these particles, A. magnetotacticum must possess a highly efficient systems to remove iron from the environment. To investigate the mechanism of iron uptake and the synthesis of magnetic particles in this organism, we will construct and screen genomic libraries of A. magnetotacticum for the iron-uptake and magnetosome-synthesizing genes. We will also use the available information on the mechanisms of iron-uptake in other bacteria to identify and characterize analogous systems, related genes, or homologous sequences in this magnetotactic bacterium. Keywords Magnetotactic bacteria Single domain magnetic particles Iron-uptake genes Siderophere TonB gene.