Spies like us (microbiologists)
This was a really cool news update, via my favorite gadget blog Gizmodo, who link to it from the New Scientist popular science site. Researchers at Tufts University have described a novel way to exchange secret messages using bacteria. The process has been dubbed SPAM, or Steganography by Printed Arrays of Microorganisms, and utilizes a panel of recombinant E. coli strains that glow under under black light. The bacterial cells have all been transformed with plasmids that encode variants of a jellyfish protein called green fluorescent protein, or GFP, which has been further engineered to create many more colors than green. The panel of glowing E. coli strains are organized in pairs, creating 49 possible characters. This allows more than enough permutations to code for all the letters of the English alphabet, the numerals 0 to 9, plus some additional characters for punctuation. I know that I am a big fan of the semicolon; I do not know how I could encode any important message if I could not use a semicolon.
The glowing E. coli colonies are laid out in a specific order that codes for an intended message on media in the lab on agar plates. The colonies can then be transferred to a thin film, which can then be mailed. The recipient must then put the film back onto a specific type of bacterial media, visualize the pattern of colored dots, then decode the message. Several layers of manipulations make this a relatively secure cypher mechanism, and it can be further strengthened by the addition of specific antibiotic requirements before the dot patterns can be seen. Furthermore, transient glowing patterns of dots can potentially be used, to make a message that can only be read for a finite amount of time, much like the self-destructing messages received in the Mission Impossible movies.
The feasibility of this process is very real, and the arrays of organisms are incredibly easy to create. The security of the method is dependent, as with any coding mechanism, on only the sender and recipient knowing the cypher that was used. One might be worried from a biosecurity standpoint whether is is prudent to ship E. coli, particularly isolates that are antibiotic resistant, through the mail. Fortunately, laboratory strains of E. coli are non-pathogenic, and grow poorly outside of the laboratory setting. The most significant danger from this scenario is that pathogens of humans might acquire the antibiotic resistance gene segments from the recombinant E. coli isolates, and therefore acquire antibiotic resistance themselves. The biggest drawback of the scenario is that it is not robust enough for large messages, and currently is only useful for small, text-based messages which presently might be sent more effectively via email. Still, I think it might be prudent to examine everything with a black light in hand for secret messages.
Posted on September 28, 2011, in Microbes in the News, Strange but True and tagged Escherichia coli, Mission Impossible, New Scientist, Steganography, Tufts University. Bookmark the permalink. Comments Off on Spies like us (microbiologists).