Scientist Make Bacteria
Behave like Computers
By Ron Weiss Princeton
Monday, May 9, 2005
Bacteria have been programmed to behave like
computers, assembling themselves into complex
shapes based on instructions stuffed into their genes.
The research could lead to smart biological devices that could
detect hazardous substances or bioterrorism chemicals, scientists
say. Eventually, the process might be used to direct the construction
of useful devices or the growth of new tissue, perhaps restoring
function to a severed spinal cord.
Many lines of research hold similar promise for controlling
biology to build useful things. Predictions do not always
come true. What’s new about this latest effort is that
the bacteria are made to communicate, so that millions or
even billions of them gather in a predictable manner.
And there are pictures to prove it.
The researchers programmed E. coli bacteria to emit red or
green fluorescent light in response to a signal emitted from
another set of E. coli. The living cells were commanded to
make a bull’s-eye pattern, for example, around central
cells based on communication between the bacteria.
Other patterns produced with this new “synthetic biology”
technique include a pretty good semblance of a heart and a
rudimentary flower pattern.
The work was led by Ron Weiss, an assistant professor of electrical
engineering and molecular biology at Princeton University.
Weiss and his colleagues engineer a special segment of DNA,
the blueprints for any cell’s operations. The segment
is called a plasmid.
“You have a segment of DNA that dictates when proteins
should be made and under what conditions,” Weiss told
LiveScience. The plasmid is inserted into a cell, and “the
cell then executes the set of instructions.”
While most real-world applications of the technique are likely
many years away, Weiss said it might be used in three to five
years to make devices that could detect bioterrorism chemicals.
The bacteria “have an exquisite capability to sense
molecules in the environment,” he said. “The bull’s-eye
could tell you: This is where the anthrax is.”
The study is detailed in the April 28 issue of the journal,
Nature.
In a paper of March 8, in the Proceedings of the National
Academy of Sciences, another team led by Weiss showed they
could insert DNA into cells to make them behave like digital
circuits. The cells could be made to perform basic mathematical
logic. The latest work expands this concept to vast numbers
of bacteria responding in concert.
“Here we’re showing an integrated package where
the cells have an ability to send messages and other cells
have the ability to act on these messages,” Weiss said.
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