Scientists from the Queen Mary University of London have finally discovered how bacteria "see" the world after over 300 years of looking and the results show that it is in a surprisingly similar way as us - using a microscopic eyeball, bacterial cells utilize the world's oldest and tiniest camera eye.
"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 team examined the cyanobacteria species "Synechocystis," which are found in freshwater lakes and rivers. Cyanobacteria evolved approximately 2.7 billion years ago and previous studies have revealed photosensors in their biology as well as their ability to perceive light source positions and move towards them through a process called phototaxis.
The current study unveils this process even further, revealing that they are able to conduct it by their bodies acting as a lens - as light hits their spherical surface, it refracts into a location on the other side of the cell, stimulating cell movement away from the focused spot. Afterwards, tentacle-like structures called pili reach out from the bacteria towards the light source, attach to the target surface and pull the bacteria towards it.
"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 likely the result of convergent evolution between bacteria and other 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 issue of eLife.
