Thursday, November 13, 2014

Bacteria Become "Genomic Tape Recorders", Recording Chemical Exposures in their DNA

Engineers at MIT have transformed the genome of E. coli into a long-term storage device for memory. Storing memory in bacterial genomes has been attempted before but previously has had little success and could only measure whether a memory of a chemical exposure occurred or not. In this method, how much exposure there was and how long the exposure occurred can now also be recorded. In order for E. coli to store memory researchers engineered the cells to produce a recombinase enzyme which can insert DNA or a specific sequence of single-stranded DNA into a targeted site. This DNA is activated by the presence of light, and once the DNA is produced the recombinase inserts the DNA into the cell's genome at a pre-programmed site. When an exposure is recorded the memory is stored for the lifetime of the bacterial population and is passed on to each generation. To determine how much exposure there was and how long it lasted researchers can measure the proportion of cells in the population that have the new DNA sequence.  Information can also be erased by stimulating the cells to incorporate a different piece of DNA in the same spot, but this method has not been perfected yet with minor flaws.

            There are many plans as to what these new “tape recorders” can be used for. Environmentally the bacteria could be used to monitor the ocean for carbon dioxide levels, pollutants, or acidity. There are also plans to put the bacteria inside of the human digestive tract to record inflammation, for victims of illnesses such as irritable bowel disease, and  dietary intake, to track the amount of sugar and fat being consumed.
            I found this article interesting more because of its uses although the research and effort put into the process is equally as intriguing. I am excited about the use of the bacterial “tape recorders” to hopefully monitor oceans and allow the scientific community to continue to care for them as much as they can in their power. The use of the bacteria would also be beneficial when put in the human digestive tract in order to give doctors information which will ultimately help their patients. Another intriguing point for me was that the memory on the genomes can even be erased by simply placing a separate piece of DNA in its spot.  


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