A fisherman boats in Chao Lake where thick cyanobacteria gather on the surface on August 5, 2015 in Chaohu, Anhui Province of China. Getty Images

Bacteria are more impressive than they look: they can survive the harsh cold and vacuum of space for more than a year, they number a tidy five million trillion trillion in number, at least, on planet Earth, and even make up around one in ten cells inside the human body.

And, it turns out, some of them can also see.


Bacterial cells can act as a form of tiny eyeball, enabling bacteria to 'see' their world.

The research sought to explain how cyanobacteria, an ancient bacterial organism which often forms a ubiquitous green slime on rocks and water, is able to sense light and carry out photosynthesis. But, until now, it wasn't known how cyanobacteria sensed and moved towards light.

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No-one else noticed it before either, despite the fact that scientists have been looking at bacteria under microscopes for the last 340 years Conrad Mullineaux, Queen Mary University of London

In a new study, researchers demonstrated that the body of a bacterial cell is able to act as a lens, refracting sunlight across its spherical surface and focusing it to a point on the other side of the cell. Sensing this, the bacteria moves toward the light source, in a process called phototaxis, and ensures its survival.

eLife

Scientists had apparently not previously considered that the bacteria itself could be a form of spherical lens, but said that it was "pretty obvious in retrospect". "The idea that bacteria can see their world in basically the same way that we do is pretty exciting," explained lead researcher Conrad Mullineaux from Queen Mary University of London. "No-one else noticed it before either, despite the fact that scientists have been looking at bacteria under microscopes for the last 340 years."


It's not just synechocystis, the type of cyanobacteria looked at in the study, either. Scientists believe that 'rod-shaped' bacteria might also be able to act as a form of optical fibre lens, trapping and sensing light before moving in the direction of its origin.

The process is important for bacteria, and increasingly for humans. The ability of bacteria to photosynthesise is being explored for use in the production of biofuels, as well as food and other useful products.

Our own vision is vastly more complex than that of bacteria, of course, but may have evolved from similar principles, according to the researchers. "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 co-author Annegret Wilde from the University of Freiburg.