On Fri, 17 Mar 2006 22:54:03 +0100, "Fabrizio" <nospam at nospam.it>
> the Helicobacter pylorii changes its form between spiral and coccoid
>one depending on enviromental condition
>http://www.sodbrennen-welt.de/science/1994/1994_7524304.htm.>>This helps the bacter to survive but I don't understand why, what are the
>advantages in changing the form? How does it happens biochemically?
Shape is determined by various proteins the bacteria make. Many
microbes (bacteria and fungi) are dimorphic -- growing with different
shapes depending on conditions. I do not know whether the details are
known for this case, but they are being worked out for some bacteria.
The shape is not a cause of the better survival, but a side effect of
the change made.