How do we know how muscles work? How can scientists tell us in such detail
about events which happen on such a tiny scale within the body? Well, modern
technology is creating tools that make more and more analysis like this
possible.
The following web page tells us about laser-based 'optical tweezers' mow
being used to manipulate and 'play with' the constituents of muscle in
efforts to understand exactly what makes us strong and how we can become even
stronger.
<http://unisci.com/stories/20004/1219003.htm>
Here are a few extracts from this fascinating article:
<Optical Tweezers Show Details Of How Our Muscles Work
Plundering a physicists' toolkit to make use of a laser-based device known as
"optical tweezers," biologists have discovered the details of how our muscles
work and how components are transported within individual cells.
As well as increasing our understanding of biology, this information could
one day be used to engineer miniature "nanomachines" that work on the same
principles.
At the Institute of Physics Condensed Matter and Materials Physics Conference
in Bristol, England, today, biophysicist Dr. Justin Molloy from York
University described an experiment that uses optical tweezers to investigate
the interactions responsible for producing movement inside cells.
Optical tweezers consist of a single narrowly focused laser beam that can
capture and move tiny particles a few millionths of a meter across. The light
in the laser beam produces a force which attracts the tiny particles,
allowing them to be moved about by moving the beam ......
All higher forms of life (from yeast upwards) have actin and myosin in their
cells and different cells use different types of myosin. Myosin can be
thought of as a molecular motor. Some types of myosin are designed to move at
high speed, others to produce high force – some can even run in reverse.
The myosin from our muscles has evolved to produce external forces and
movements, and gives a short sharp kick as it breaks down each molecule of
ATP. Inside a muscle cell, billions of these myosin molecules operate
together to produce large forces (e.g., when we lift heavy weights) and rapid
movements (e.g. when we run).....
Having already discovered the sharp kick muscle myosins produce, the York
team have recently been looking at the myosins responsible for providing
tension in the membrane that surrounds every cell in our body. These myosins
are adapted for producing force over long periods of time.
"This is the first time it's been shown at the level of a single molecule
that a motor can produce two kicks of mechanical movement for one molecule of
ATP broken down," Dr. Molloy says.
The researchers plan to continue their experiments and investigate a whole
range of other myosins.>
***By the way, for a short discussion of some of these myosins, see my
"Supertraining" book (2000), Chapter 1.12 (Types of Muscle Fibre).
Dr Mel C Siff
Denver, USA
http://www.egroups.com/group/supertraining
|