Genetic Engineering of Single-Domain Magnetic Particles

• Main Author: Waleh, Nahid S
• Format: Report
• Language: English
• Subjects: AQUASPIRILLUM MAGNETOTACTICUM; ASSIMILATION; BACTERIA; CELLS(BIOLOGY); CULTURES(BIOLOGY); EFFICIENCY; ENTERIC BACTERIA; GENE MAPPING; GENES; GENETIC ENGINEERING; Genetic Engineering and Molecular Biology; IRON; MAGNETIC FIELDS; MAGNETOSOMES; MAGNETOTACTIC BACTERIA; MAPPING; Microbiology; NUTRITION; PARTICLES; PE61153N; PRODUCTION; PURITY; REQUIREMENTS; SIZES(DIMENSIONS); SYNTHESIS

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 system(s) to remove iron from the environment. To investigate the mechanism of iron-uptake and the synthesis of magnetic particles in this microorganism, 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 We have determined already that the genes of A magnetotacticum are functionally expressed in E. coli. Furthermore, we have identified in this bacterium a sequence homologous to the tonB gene of E. coli. The tonB gene is known to be required for iron assimilation in enteric bacteria. The long-term goal of this project is to clone the identified genes in a suitable host organisms that would make the large- scale, regulated production of single-domain magnetic particles possible. Keywords: Gene mapping; Magnetosomes.