eLIFE (VIA EUREKALERT)A cyanobacterial cell acts like an eye, refracting light onto the cell membrane in a similar way to how the lens of a human eye refracts light onto the retina, according to a study published yesterday (February 9) in eLife. The findings contradict previous suggestions that the bacteria achieve phototaxis by sensing light gradients, and answer a question first asked by scientists more than three centuries ago.
“The fact that bacteria respond to light is one of the oldest scientific observations of their behaviour,” said study coauthor Conrad Mullineaux of Queen Mary University of London in a press release. “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.”
Although previous studies had shown that cyanobacteria could use photoreceptors inside the cell to sense and move toward a light source, the precise mechanism of phototaxis was unknown until now.
Mullineaux and colleagues showed that a cyanobacterium, about half a billion times smaller than the human ...
