Your colon houses an ecosystem

The probiotic movement has taken a giant step forward this week with word of two new studies exploring the world inside your colon.

First, turns out it's a complex world down there. There may be 50 different kinds of bacteria in our guts, and the mix differs.

Some mixes let food pass, others gobble the nutrients, and how they interact with different foods can differ as well.

Masashi Yanigasawa writes that these bacteria mainly operate on a single receptor molecule in the intestines, called Gpr41. Blocking that signal could help control weight. He notes you have more bacteria in your gut than cells in your body.

The solution would come in customized probiotic shakes that block the signal. One point not made is that shakes which enhance the signal could benefit populations prone to malnutrition, helping them get more from their food.

All this is going into the Proceedings of the National Academy of Sciences.

Second is a report from Australia on how bacteria could be custom-made. This offers a new approach from current antibiotics, the creation of bacteria aimed at fighting those causing disease.

In one example, the lab at the University of Adelaide engineered a harmless E.Coli to excrete a substance useful in treatment of HIV.

Adrienne and James Paton warn that these bugs are very short-lived, and keeping them that way may be key to getting them approved for use.

Their research is being discussed in Nature Reviews Microbiology, and the field will get its own journal in 2010, called Bioengineered Bugs.