Oxygen can be deadly to anaerobic bacteria, hence sinking deeper down a lake or sea can help save the organisms. To this end, various species of bacteria are able to use the Earth’s magnetic field to orient themselves when searching for the bottom. By studying the genomes of different organisms that use natural magnetic compounds in structures called magnetosomes, scientists from Tokyo University of Agriculture and Technology may help bring about a way to take advantage of bacterial navigation properties for biomedical applications.
The shape and composition of magnetosomes are species- and strain-specific, suggesting that magnetosome synthesis is biologically controlled. Magnetosomes are currently difficult to harvest in large quantities or synthesize artificially, therefore deciphering how cells form magnetosomes is crucial if they are to be useful in new technologies.
Genetic analyses have been performed in closely related magnetotactic bacteria, but because magnetosomes are also found in other classes of bacteria, scientists do not yet have a clear picture of the genetic components necessary for magnetosome formation. Tadashi Matsunaga of the Tokyo University of Agriculture and Technology and colleagues recognized that by analyzing the genome of more distantly related magnetotactic bacteria, researchers may be able to clearly define the minimal gene set needed for magnetosome synthesis.
In this work, Matsunaga’s group sequenced the genome of Desulfovibrio magneticus strain RS-1, a more distant relative of other magnetotactic bacteria previously studied, and is also known for the unique bullet-shape of its magnetosomes. “Understanding the genes that control the morphology of these magnetosomes would be a significant breakthrough,” said Matsunaga, noting that RS-1 could be the key to opening up new applications for magnetosomes.
Comparing the RS-1 genome sequence to the genomes of other magnetotactic bacteria, the team determined that all magnetotactic bacteria contain three separate gene regions related to magnetosome synthesis. Surprisingly, they also found that magnetosome-related genes are very well conserved across different classes of bacteria. Matsunaga explained that this suggests that the core magentosome genes may have been established in these bacteria by several horizontal gene transfer events, rather than being passed down through a lineage.
Image: Transmission electron micrograph of magnetotactic bacterium, Desulfovibrio magneticus strain RS-1, showing a chain of bullet-shaped magnetosomes aligned along the Earth’s magnetic field.
Press release from Cold Spring Harbor Laboratory: Magnetic microbe genome attracting attention for biotech research …
Abstract in Genome Research: Whole genome sequence of Desulfovibrio magneticus strain RS-1 revealed common gene clusters in magnetotactic bacteria
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