Could this biological photograph be evidence of the Flying Spaghetti Monster? Courtesy of Aaron Chevalier.
Who knew E. coli was so photogenic? A group of moonlighting student researchers have made a photographic film out of bacteria, allowing them to take photographs with the first “biological camera.”
Looking at the photographs is likely to give you a sense of déjà vu, rather than a case of E. coli poisoning (the bacteria strain being used was not the dangerous one). The photos look eerily like the static works of the early 1800s. The new photos require similarly-long exposure times—six to eight hours—but the bacterial plate develops a positive without further processing.
“It started out as a side project; we were interested in the emerging field of synthetic biology,” said Jeff Tabor, a graduate student from the University of Texas at Austin who worked on the project, referring to the discipline that seeks to build biological machinery using molecular parts. They used E. coli because its molecular mechanisms are well known and its DNA is easily manipulated.
Still, there was an obstacle that stood in the way of the research team. “The light-responsive E. coli gene doesn’t occur in nature,” said Tabor. “It had to be engineered.”
The Austin group collaborated with a lab at the University of California San Francisco, which took an algae gene that codes for a light sensing protein and inserted it into the genome of E. coli. Once the bacteria were reactive to light, the students used “off-the-shelf” synthetic biology parts, provided by other researchers, to finish their machine.
In order to take a picture, the researchers created a lawn of bacteria on a plate coated with a sugar called S-gal, which doubles as a dye. The lawn is exposed with a laser through an image mask, beginning a sequence of controlled reactions. At the end of the sequence, the bacteria exposed to the light release an enzyme, LacZ, that reacts with the sugar, creating a black pixel under each E. coli.
Theoretically, images could be made with a resolution of 10,000 dpi or about 100 megapixels per square inch. In reality, the photos aren’t that sharp, due to the limitations of bacterial growth. So far, the Austin team has taken less than 10 snapshots—one of them in the image of the infamous creationism debunker, the Flying Spaghetti Monster.
Say “E. Coli!” A biological photograph of the researchers. Courtesy of Aaron Chevalier.
“It’s a fun thing that we were pursuing in part because of entertainment value and in part because there was actually a serious scientific pursuit, which is the ability to control gene expression spatially, without interfering with cells,” said Edward Marcotte, an associate professor at UT and one of the team’s supervisors.
The team hastily entered their work into the 2004 intercollegiate Genetically Engineered Machine competition (iGEM), and came away with first prize for their biofilm. It’s been a thrill for the undergraduates, who are publishing their first paper (the work appears in the November 25th issue of Nature).
Aaron Chevalier, a senior in physics at UT, who built the camera system, said, “This is probably going on the top of my CV right now.”
Chevalier said the team has no shortage of ideas for future research using the light-sensitive bacteria—color photography using multiple light-sensitive proteins would be a possibility—but there are no “killer apps” in the works. For now, they’re working with the monochromatic images, improving their contrast and plating techniques.
“We actually have it down enough that we can crank out pretty good pictures fairly frequently,” Chevalier said.
“I’m going to image an E .coli on a plate of E. coli,” he added. “Just call it an E. coli self-portrait.”
“We actually did a ‘Virgin Mary’. We talked about selling it on eBay.”
Originally published November 28, 2005