[thedoc (OP)]

Simon asked the Naked Scientists:
   My mother mentioned that bacteria could be evolved on demand, by varying sugars available to them.

However quick Google gives Lenski, who only got results after my mother was dead.

Since my mother worked on classifying food pathogens before modern sequencing, when the sugar consumed was part of the classification, she was undoubtedly referring to some specific experiments. Does anyone know which?
What do you think?

[evan_au]

Perhaps she was talking about evolution of a bacterial population (what we would now call a microbiome)?

Certain bacteria can metabolize certain sugars, but not others. By changing the content of the food source, we will kill off some species, and encourage the growth of different species.

Even within a single species, some individuals have more active enzymes. Changing the food composition encourages growth of strains that are more effective at processing the restricted diet.

Lenski's experiments started in 1988, and it was known that E.Coli had the basic machinery to process citrate. It was also known from wild strains that it was possible to turn on citrate metabolism in aerobic conditions, so Lenski was investigating how many mutations it took to express this capability in the lab.

Could your mother have been referring to the early days of Lenski's experiment? (1988)

Or could she have been referring to even earlier experiments, which, due to the lack of genetic testing, could have been rapidly contaminated by wild strains, with no way of identifying this fact? Lenski's team had to regularly freeze "backups" of each population, so they could "restore" the experiment after contamination by wild strains.

See: http://en.wikipedia.org/wiki/E._coli_long-term_evolution_experiment