I met Timo Diehl in Berlin, by the happy accident that he lived next door to a friend of mine. He is something of a “Jack of all sciences”, being a mathematician who’s worked in physics and now, microbiology. He also rose magnificently to the challenge of finding me peculiar figures of speech and unlikely translations into German. But when I found out last year that he was working in experimental evolution, I got shouty-excited had to know more!
Experimental evolution is exciting because, of course, evolution is something that typically happens over a mind-boggling length of time. To have a system that lets scientists see evolution happening over a readily observable period is, needless to say, a bit good. The other thing that had lasers shooting from my eyes with delight was the mention of an “evolution machine”. Of course, it’s not quite the chamber that first sprang to mind (resembling the teleporter in The Fly), but is still an impressive invention.
Experimental evolution is based on the ability of bacteria to mutate (relatively) quickly, and the fact that different micro-organisms have different environments in which they can live happily. That’s how fermentation preserves food: it creates an environment that favours belly-friendly microbes and is hostile to harmful types.
As I understand it, the evolution machine can function as a kind of gladiatorial arena in which different strains of bacteria compete (see Timo’s article below) or to test the ability of a strain of bacteria to adapt to changes in its environment. The latter is where it gets really interesting, because bacteria can’t just put on a woolly coat when it gets a bit chilly, for example: adaptation in this sort of situation requires mutation, with favourable mutations resulting in a new species that can survive in an environment that would have killed off its predecessor. The process of mutation is random, but the result is not, thanks to natural selection. It means that if a certain mutation allows the bacteria to survive better in the new conditions, these bacteria will grow faster and out-compete those without the handy mutation. The resulting adaptation may be slow by human standards (a couple of years), but is the blink of an eye relative to the evolution of the plants and animals we see around us.
That’s enough inexpert rambling from me. It’s over to Timo now to describe – in epic style – his own adventures in experimental biology.
There can be only one. The Highlander Bacteria.
Once upon a time in a microcosm far, far away, there was a field where, peaceful and without concern, bacteria dwelled – probably amongst other fellow bacteria, but in as much harmony as there is in a microcosm.
But lo! on the eve of a rainy day in March, a sterile tube was brought forth and dug deep into the very heart of the soil. Twelve grams of said soil were taken and carried away to a known institute of a town called Berlin. The soil and the bacteria within were put in an evolution machine to let them struggle, taxon against taxon, in mortal combat. The hypothesis was that after a while there would be only one left, and indeed, after two weeks of intense struggling amongst the bacteria, One was left.
Who is this One, the last of its kin, Duncan McBacteria, the stem that boldly went where no scientist ever expected?
Further tests must be conducted, more data must be gathered to dig deep and greedy into the essence of this phenomenon.
And indeed, tis a phenomenon of great curiosity, for the growth rate of Duncan McBacteria compared to its better investigated relative E. coli is hundredfold. Test after test was run, sweat was spoiled and Eppendorf tubes shattered before the final test was complete and the identity revealed. Behold! the One bacteria is Citerobacter diversus. For him the journey is over, but for us it has only just begun, for further places hold other stems and maybe there are other discoveries that lie in store for us beyond the bounds of human experience.
20 May 2012