infographic credit:
elife
(February 9, 2016) After
more than 300 years of looking, scientists led by Queen Mary University of
London, have figured out how bacteria “see” their world. And they do it in a
remarkably similar way to us.
A team of British and German researchers reveal in the
journal eLife how bacterial cells act as the equivalent of a microscopic
eyeball or the world’s oldest and smallest camera eye.
“The idea that bacteria can see their world in basically the
same way that we do is pretty exciting,” says lead researcher Conrad
Mullineaux, Professor of Microbiology from QMUL’s School of Biological and
Chemical Sciences
Cyanobacteria are found in huge numbers in water bodies or
can form a slippery green film on rocks and pebbles. The species used in the
study, Synechocystis, is found naturally in freshwater lakes and rivers.
Cyanobacteria evolved around 2.7 billion years ago and the fact that they are
able to produce oxygen and fix carbon dioxide using energy from the sun –
photosynthesis - is thought to have caused mass extinctions and the oldest
known ice age.
As photosynthesis is crucial to the survival of these
bacteria, scientists have sought to understand how they sense light.
Previous studies have shown that they contain photosensors
and that they are able to perceive the position of a light source and move
towards it, a phenomenon called phototaxis.
The current study reveals that they are able to do this
because the cell body acts like a lens. As light hits the spherical surface, it
refracts into a point on the other side of the cell. This triggers movement by
the cell away from the focused spot.