Scientists Perceive That Bacteria Act As Tiny Eyeballs To 'See' Surroundings
Researchers from the Queen Mary University of London can now understand how bacteria "see" the world. Surprisingly, they see as we do----through an eyeball!
With a microscopic eyeball, the bacterial cells peep through the world's "oldest and tiniest camera eyes".
"The idea that bacteria can see their world in basically the same way that we do is pretty exciting," Conrad Mullineaux, lead researcher of the study, said in a press release.
The research team examined lakes and rivers and studied the cyanobacteria species "Synechocystis." These cyanobacteria started to evolve 2.7 billion years ago. Earlier, photosensors were detected in their biology. Their ability to see the light source positions and gravitate towards them through phototaxis has also been documented.
The bacteria make their bodies behave like lens. When light hits their spherical surface, it refracts into a place on the other side of the cell, which stimulates cell movement away from the particular spot. Later, tentacle-like structures, also called pili, reach out from the bacteria and head for the light source. They then attach themselves to the target surface and pull the bacteria towards them.
"The fact that bacteria respond to light is one of the oldest scientific observations of their behaviour," Mullineaux said. "Our observation that bacteria are optical objects is pretty obvious with hindsight, but we never thought of it until we saw it. And no one else noticed it before either, despite the fact that scientists have been looking at bacteria under microscopes for the last 340 years."
The findings are probably due to convergent evolution between bacteria and different, more complex organisms, such as animals and humans.
"The physical principles for the sensing of light by bacteria and the far more complex vision in animals are similar, but the biological structures are different," said Annegret Wilde, coauthor of the study.
The findings were published in the Feb. 9,2016 issue of eLife.