Phototaxis is the ability of certain cells to move towards light, a phenomenon discovered by biologists a century ago but still not understood. So far, as a surprising study published in e-Life magazine reveals how at least one variety of single-celled entity called Synechocystis does .
This microorganism belongs to the phylum of cyanobacteria – formerly known as blue-green algae – very abundant in nature. Synechocystis , which has a spherical shape and measures around three thousandths of a millimeter, crawls with small villi or pili towards places where there is light , which it needs to produce energy and develop.
Coincidentally, the researchers were examining the movement of Synechocystis specimens under a microscope when they detected that the light set as “bait” was reflected within them . They then did more experiments with lasers and found that an image of the light beams was focused on the opposite side of the bacteria. In other words, the entire body of Synechocystis acted as a tiny spherical lens or camera.
The mechanism is therefore, basically, the same one used by the human eyeball , 500,000 million times larger than this microbe. Then small molecules called photoreceptors capture this focused light and ignite the cyanobacteria toward the source that emits it. Synechocystis is arguably the oldest and smallest example of an ocular lens found to date.
The next step is to find out if other bacteria or single-celled beings also incorporate this visual mechanism.
