Researchers at the Wyss Institute and Harvard Medical School have discovered a method involving yeast for inducing magnetic sensitivity in an organism that is not naturally magnetic.
Magnetic fields are everywhere, but few organisms can sense them. Those that do, use magnetic sensitivity as a natural global positioning system to guide them along migratory routes. How these few magnetically aware organisms gain their magnetism remains one of biology’s unsolved mysteries.
Researchers Pamela Silver, PhD, a professor of biochemistry and systems biology and Keiji Nishida, PhD, research fellow in systems biology at Harvard Medical School, were able to imbue yeast with similar properties. “Magnetism in nature is a mysterious biological function that very few living systems exploit,” says Silver.
The presence of iron can cause magnetism, but most cells, if exposed to this common metal, hide it away in sealed-off cavities where it cannot have an effect. Silver and Nishida were able to block expression of the protein that causes the iron sequestration, allowing the iron to circulate freely throughout the yeast cell. In this way, they created enough magnetic sensitivity in the cell to cause it to migrate toward an external magnet.
The researchers found a gene that correlates with magnetism by instructing the production of a critical protein that can dial up magnetism. They enhanced the magnetic sensitivity through interaction with a second protein that regulates cell metabolism. Since the same metabolic protein functions similarly in cells ranging from simple yeast to more advanced—even human—cells, the method could be applied to a range of organisms.
Silver notes that in an industrial setting, magnetization could be helpful as a means of targeting and isolating specific cells. Contaminated cells could be pulled out and disposed of during the processing of biological materials, and cells that are critical to a certain manufacturing process could be isolated and put to use. Magnetic cells could also be used to interact with non-living machinery. For example, magnetism could be used in tissue engineering to guide cells to layer themselves on a scaffold in a specific way. New therapies may be created in which cells are engineered to respond to a magnetic field by growing or healing, and implanted magnetic stem cells may be tracked with magnetic resonance imaging.
“This work shows how design principles from one type of cell can be harnessed using synthetic biology to transfer novel functionalities to another, which is a core approach driving the field of biologically inspired engineering,” says Donald Ingber, MD, PhD, Wyss Institute founding director. “The ability to control cells magnetically will also synergize with many other technologies that rely on use of magnetic fields to control cell functions remotely, or to isolate rare cells from biological fluids.”
The research findings appear in PLoS Biology.
Release Date: Feb 28, 2012
Source: Wyss Institute for Biologically Inspired Engineering-Harvard University
