Gotta Get Bacteria in Time!

Jonathan Strickland

A scanning electron micrograph of Lactobacillus casei bacteria. Are these the machines of the future? | © Steve Gschmeissner/Science Photo Library/Corbis

The microscopic world is fascinating and strange. Using some advanced techniques in clean rooms, we've made great strides into the nanoscale world using silicon and exotic metals. Engineers command computers to etch designs onto wafers -- designs so small, not even a powerful light microscope can detect the details. But when it comes to the microscopic biological world, we're the equivalent of a cave man hitting one thing against some other thing in the hopes that he'll master the mystery of fire.

That's not to say we haven't learned plenty of useful stuff about microbiology. My point is just that nature has had millions of years to play around with microbes. It turns out all that time has allowed nature to get a pretty good grip on what works. We're only in the earliest stages of learning the amazing applications of the microbiological world.

Take bacteria, for example. Scientists discovered that using modified E. coli in a particular way could let us solve traditionally difficult logic puzzles. One of those puzzles is the Hamiltonian Path Problem -- that's when you have a bunch of interconnected nodes. Not every node has a direct pathway to every other node -- some may have connections to only one or two nodes. Your task is to find a pathway that allows you to visit each node once and only once. The more nodes you add, the harder the problem becomes.

So how can a single-celled organism with no brain solve a riddle that would have most of us gnawing through a package of number two pencils as we trace yet another failed pathway? First, scientists modified the E. coli's DNA so that genes represented the various nodes. The genes would cause the bacteria to glow red or green. If the DNA shuffled together and formed a successful navigation of the nodes, the bacteria would glow both colors and turn yellow. You can read more in The Guardian.

Instead of setting a computer to work on a problem and waiting for it to go through and validate or eliminate potential answers one at a time, this bacterial approach relies only on DNA combining in thousands of ways. The "answers" to a problem become evident when the bacteria display some particular trait -- such as color in the above example. You discard everything else and then examine the answers to learn the way to solve the problem. It's a bit circuitous but it could potentially revolutionize the way we approach certain types of computational problems.

That's not the only thing bacteria can do, though. We can use bacteria to do physical work -- turning gears that are millions of times larger than the bacteria themselves. Normally, the bacteria would move around a suspended fluid in seemingly random ways. By controlling the presence of oxygen in the fluid, scientists could force the bacteria to push against tiny gears, turning them. These tiny gears might one day be part of complex microscopic devices -- perhaps even ones that roam our bodies and help protect us from disease. You can read more about it in Popular Science.

There's also this study, which shows that bacteria can emit high concentrations of the chemical compound isoprene. This compound is important in the production of rubber, which goes into lots of stuff, including tires. Our consumption of rubber and the supplies we have available are leading to an unsustainable situation. If we can harness bacteria to produce isoprene, we may be able to meet our needs harnessing the power of bacteria.

Then there's the fact that bacteria succeeded where countless alchemists failed -- a type of bacteria can actually transform the toxic substance gold chloride into pure gold. Sure, it's not enough to upset the world markets or anything, but we may be able to use this to our advantage in other ways as we use gold in electronics and other applications.

We're also using bacteria in sensors too. By gold-plating certain types of bacteria, we can create sensors that can detect incredibly tiny changes in humidity. Other bacteria are adept at detecting the presence of ammonia. There may be millions of ways we could apply bacteria to make our lives better.

The discoveries scientists are making in microbiology fuel my excitement for the future. Why reinvent the microscopic wheel when we can copy (or even just repurpose) what's already in nature? Doing so will make discoveries and advances arrive at our doorstep much more quickly. And who would have thought the same stuff that can give you a terrible case of food poisoning could one day solve complex computer problems? SCIENCE!