Micro Midwives

by David Sugarman

Most of us have seen amoebae in school — those microscopic bits of moving jelly.

They're complete single-celled animals lacking brains and nervous systems, so you might not expect much of them in the way of purposeful behaviour. But they can do all that's necessary for an organism to get by in the world — find food and eat, avoid danger and reproduce. (When amoebae reproduce, they simply divide in two, just like our cells do.)

Now it seems another type of behaviour can be added to the list — co-operation.

When amoebae divide into two cells, there sometimes remains a tube-like connection between the cells that they can't seem to break by themselves. Scientists in Israel have discovered another amoeba that approaches and forces the dividing cells apart.

The scientists found that the dividing cell released a substance that diffused through the water and signaled the 'midwife' amoeba to come and help. Other amoebae sometimes approached, but only one acted as the midwife. It took two to three minutes after the amoeba started to divide for the midwife to start approaching, and less than a minute for it to break the connection and force the two new cells apart. The scientists discovered that they could pick up some of this chemical in a glass tube and an amoeba would follow it around for more than 30 minutes. This whole process seems to be one way for cells to effectively deal with problems in reproduction.

Perhaps this type of behaviour may even help us to understand learn more about what goes on inside us — after all, our white blood cells are very amoeba-like. And maybe it's just another indication of just how surprising and wonderful life really is.