Hyper-Evolution von Bakterien in der Mega Plate-Petrischale

An der Uni Harvard haben sie eine riesige Petrischale gebaut, die „Mega Plate“. In der sind fünf verschiedene Konzentrationen von Antibiotika (keine, einfache Konzentration, 10x, 100x, 1000x) voneinander getrennt, mit ein paar wenigen durchlässigen Stellen. In dieser Mega Plate mutieren nun Bakterien um die Wette und entwickeln im kürzester Zeit eine Resistenz gegen die Antibiotika. So lässt sich beinahe mit bloßem Auge Evolution beobachten, die Viecher kommen nach anderthalb Wochen mit der tausendfachen Konzentration klar.

The Atlantic: Stunning Videos of Evolution in Action und Harvard mit der deutlich besseren Headline: Bugs on Screen. (via Marginal Revolution)

mutIn a creative stroke inspired by Hollywood wizardry, scientists have designed a simple way to observe how bacteria move as they become impervious to drugs. The experiments are thought to provide the first large-scale glimpse of the maneuvers of bacteria as they encounter increasingly higher doses of antibiotics and adapt to survive—and thrive—in them. […] To do so, the team constructed a 2-by-4-foot petri dish and filled it with 14 liters of agar, a seaweed-derived jellylike substance commonly used in labs to nourish organisms as they grow.

To observe how the bacterium Escherichia coli adapts to increasingly higher doses of antibiotics, researchers divided the dish into sections and saturated them with various doses of medication. The outermost rims of the dish were free of any drug. The next section contained a small amount of antibiotic—just above the minimum needed to kill the bacteria—and each subsequent section represented a 10-fold increase in dose, with the center of the dish containing 1,000 times as much antibiotic as the area with the lowest dose.

Over two weeks, a camera mounted on the ceiling above the dish took periodic snapshots that the researchers spliced into a time-lapsed montage. The result? A powerful, unvarnished visualization of bacterial movement, death and survival; evolution at work, visible to the naked eye.