"Once we imaged the M. hungatei, we noticed how dark the granules appeared," said Zhou, a researcher at the CNSI. "The darkness arises from their density, and by studying this density, we discovered their energy-storage capacity."
The group was able to determine the granule density about four times that of water by using a Titan scanning transmission electron tomography (STEM) microscope, cryo-electron microscopy, and energy-dispersive X-ray spectroscopy, all part of the EICN lab's extensive tool set.
The tiny granules, which account for less than 0.5 percent of the cell, are so efficient that they each store 100-fold more energy than the entire rest of the cell. Each M. hungatei produces two granules, one at each end of the cell. Because all M. hungatei produce granules in the same location, and typically at the same time in their life-cycle, it is likely that their DNA contains specific genetic instructions for the creation and positioning of the granules.
The researchers hope to utilize knowledge gained from the recent sequencing of the M. hungatei genome by the U.S. Department of Energy Joint Genome Institute to further study the structures. If the specific genetic instructions for creating granules can be found in the genome, it might be possible to use the granules as a sort of chemical battery for engineered synthetic cells.
Beyond their energy-storage capacity, M. hungatei still have more secrets to reveal, according to the researchers. They also produce a distinct nan
|Contact: Jennifer Marcus|
University of California - Los Angeles