Closeness Counts

The news item below is a bit technical, so here is the gist:

Every cell in our body is continually sensing and responding to tiny chemical, electrical, and temperature changes created by nearby organisms without physical contact. As a result, cells alter their physical structure in response to the presence of other living things, including reshaping themselves to move toward or away from their neighbors.

A single atom or molecule, without even touching the cell, can move it.

When great big bundles of such cells get close, as in my CEO executive coaching groups, no one goes away unchanged!

You have a tangible effect on the people around you, without speaking or touching, as they do on you. Who you are, in fact, is largely a product of your interactions with those near you.

A reminder to us all to be responsible for our impact.

Here's what happens. First, receptors in the membranes of the cells become activated by the presence of trace amounts of chemicals--even down to the nano-molar level or about one molecule in a cubic micron--in the cells' vicinity. Not only do the receptors sense the presence of the attractants but, through the differential activation of 10,000 or more receptors distributed along the body of the cell, the direction of the source of the attractant can be located to within a few degrees. Ability to train upon a 5% chemical gradient allows the cell to know where it should be going, whether to find food, antigens, or to take up its place in a larger multi-cellular structure. Second, a cascade of polymerization steps now ensues within a few minutes. Consequently the cell develops head and tail structures, the better to make possible travel along the chemical gradient (chemotaxis).

In nature, cells have also been known to plan their travel by exploiting thermal gradients (thermotaxis) and electrical gradients (galvanotaxis). (Gamba et al., Physical Review Letters, 12 October 2007)

? PHYSICS NEWS UPDATE

The American Institute of Physics

Bulletin of Physics News

Number 842 October 9, 2007

by Phillip F. Schewe

 See also on this blog, Bad presentation–or resistant audience?

 Original post can be found here.