Can single-celled organisms see? Just as it is. Researchers have discovered that each Cyanobacterium such as a tiny eyeball works. Vibrant nano-technology.They are considered perpetrators of “large oxygen disaster” the cyanobacteria because until they brought the oxygen in the atmosphere. This tiny Earth’s atmosphere changed so persistent about 2.5 billion years ago by a primitive form of photosynthesis, that all life could develop. Cyanobacteria occur everywhere, where there is light: in the ice, deserts, rivers and lakes, but also on house walls and aquariums. Photosynthesis provides them the life energy.
Cyanobacteria can stream to very precisely on a light source
Long, it was unclear what mechanism allows this primitive form of life to flow directly and precisely to a light source. An international team of scientists London (QMUL) and other institutions from the United Kingdom and Portugal has now this mystery from the Karlsruhe Institute of technology (KIT), the University of Freiburg, the Queen Mary University solved. Each of the small cyanobacteria works like a tiny lens eye. So, they can perceive the light direction and respond accordingly. The study was published in the scientific journal “eLIFE” now.
Colleague helped with random
As so often with scientific breakthroughs colleague helped chance the knowledge gained. “The cooperation started during a lunch in Freiburg”, reports Jan Gerrit Korvink, head of the Institute for micro-structure technology (IMT) at the KIT. “Conrad Mullinieux, Professor at the QMUL, attended just the Freiburg Professor Annegret Wilde work group and asked me if I knew a way to measure the refractive index of a tiny bacterium. The refractive index describes a significant optical property of lenses that break the light.”
Lack of appropriate measuring instruments
Jan Gerrit Korvink had to be careful. “Bacteria with a diameter of three micrometers – three millionths of a meter are so small that simply appropriate devices are missing, to make such a measurement.” But then an idea came to him.
He and his team at KIT coated a flat disk of silicon with a very thin layer of a photo-polymers. This hardens under ultraviolet light. On this so light sensitive prepared plate they placed some cyanobacteria and switched up the UV lamps.
Bacterial concentrates light
With surprisingly clear result: “Everywhere where no bacteria were placed, the light fell evenly on the plate and also the polymer hardened out evenly. But the light was bundled in areas with bacteria. It formed a concentrated jet of Nano from photons so that the polymer below the bacteria in a specific pattern of hardened”, explains Jan Gerrit Korvink.
The so exposed polymer fixed the researchers chemically and then given the surface structure with an atomic force microscope. So was understandable, as the bacteria have broken the light. “Finally we could using a simulation determine the exact light bonding properties of cyanobacteria and predict” Korvink reports.
Filamentary processes outside the cell
Each Cyanobacterium actually works like a tiny eyeball. The light falling on the round surface, where it is broken by a microscopic lens. There is a focal point on the opposite side of the cell. Exactly in this focal point, the light intensity is greatest.