It's difficult to imagine a single-celled miroorganism planning for the future, but according to a paper by two research teams in Isreal that's exactly what some bacteria are doing.

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The paper, which appears in the June issue of Nature, describes E. coli who are conditioned to pre-respond to their environment. E. coli in the gut are exposed to the same sugars, in the same order, over and over agian. When the bacteria are exposed to lactose they know they will see maltose next. In preparation for this they kick on maltose digestion genes. They are conditioned to associate one the presence of one sugar with the expectation of another. it's a little reminiscent of Pavlov's dogs salivating in response to a bell.

If the cells are removed from this conditioning environment and grown under circumstances where the presence of lactose is not followed by maltose the cells will eventually lose their conditioning. Eventually they will not turn on maltose digestion genes in response to maltose. Pavlov saw the same effect when he stopped feeding his dogs every time he rang the bell.

While a conditioned response may not be the same as planning ahead it seems pretty stunning that it can occur in a single cell.

To read the paper, click here.