Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Shedding Light on Bacteria

09.02.2016

The tiny cyanobacteria use the principle of the lens in the human eye to perceive light direction

Scientists have been trying to figure out how it is possible for bacteria to perceive light and react to it ever since they started using microscopes 300 years ago. An international team led by the Freiburg biologist Prof. Dr. Annegret Wilde has now solved this riddle: In studies on so-called cyanobacteria, the researchers demonstrated that these tiny organisms of only a few micrometers in size move toward a light source using the same principle of the lens in the human eye. The study was published in the journal eLife.


The light hits the round cells of the bacterium, where it is focused by a microscopically tiny lens. This creates a focal point on the opposite side of the cell. Source: Nils Schürgers

Cyanobacteria have populated Earth for 2.5 billion years and can be found anywhere where there’s light: in ice, deserts, rivers, and lakes, as well as in the walls of buildings and in aquariums. They use light to produce energy by the process of oxygenicphotosynthesis .

In the oceans, which cover roughly 70 percent of Earth’s surface, oxygen-producing cyanobacteria are among the most important photosynthetically active organisms and are thus a central component of the biosphere. The Wilde group together with an international team discovered that cyanobacteria, which can move directly and precisely toward a light source, use their micro-optic properties to identify where the light is coming from.

The light hits the surface of the round unicellular organisms, where it is focused as if by a microscopically tiny lens. This creates a focal point on the opposite side of the cell. The cells then move away from this point of high light intensity, causing them ultimately to move toward the natural light source.

All previous attempts to explain bacterial phototaxis, the process by which bacteria move toward light, have failed because these organisms, which measure only a few lengths of a light wave, were thought to be too small to perceive differences in light between the front and back side of the cell.

Since the entire bacterium functions like a lens, however, the organisms can concentrate light, creating a pronounced light gradient within the cell. “This physical principle is actually hardly different from the way light is focused in the lenses of our eyes,” explains Wilde. “We now want to conduct further joint projects to investigate the concentration of light in microscopic organisms that do not necessarily need to have the shape of a round lens but, for instance, can also concentrate light like an optical fiber.”

A better understanding of the microoptic properties could lead to insight on the extent to which the structure and form of cells and biofilms influence the process of light collection. This knowledge could be used in the future to construct custom-made photobioreactors or to improve new types of solar cells.

Annegret Wilde has served since 2012 as professor of molecular genetics at the University of Freiburg. The study included scientists from the Institute of Biology III as well as the university’s Freiburg Institute for Advanced Studies (FRIAS). The team collaborated strongly with researchers from Karlsruhe and London, England. A key participant in the study was Prof. Dr. Conrad Mullineaux from London who visited Freiburg as an FRIAS external fellow.

Original publication:
N. Schuergers, T. Lenn, R. Kampmann, M. V. Meissner, T. Esteves, M. Temerinac-Ott, J. G. Korvink, A. R. Lowe, C. W. Mullineaux, A. Wilde (2016): Cyanobacteria use micro-optics to sense light direction. In: eLife. DOI: 10.7554/eLife.12620

Contact:
Prof. Dr. Annegret Wilde
Institute of Biology III
University of Freiburg
Phone: +49 (0)761/203-97828
E-Mail: annegret.wilde@biologie.uni-freiburg.de

Caption:
The light hits the round cells of the bacterium, where it is focused by a microscopically tiny lens. This creates a focal point on the opposite side of the cell. Source: Nils Schürgers

Weitere Informationen:

http://www.pr.uni-freiburg.de/pm/2016/pm.2016-02-09.17-en?set_language=en

Rudolf-Werner Dreier | Albert-Ludwigs-Universität Freiburg im Breisgau

More articles from Life Sciences:

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

nachricht Pollen taxi for bacteria
18.07.2018 | Technische Universität München

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>