Light-sensing protein illuminates sun-loving ocean bacteria
About 13% of bacteria near the oceans surface contain proteorhodopsin, a membrane protein able to harness sunlights energy, according to a new study by Oded Beja and colleagues in the open-access journal PLoS Biology. Given the dearth of nutrients in their environment, these oligotrophic bacteria must generate their energy from a variety of sources. The study reveals that proteorhodopsin is uniquely suited to capturing the high-radiation sunlight that illuminates the sea. Through the use of meta-genomic analysis, the authors also observed great diversity among proteorhodopsin genes.
Ocean bacteria with the light-sensitive proteorhodopsin enzyme live several meters above this coral reef. (Photo: Boaz Harel)
Estimating the average size of the bacterial genome led Beja and colleagues to the conclusion that about 13% of ocean bacteria encode proteorhodopsin. "This is a big chunk of the population that is harvesting light in a different way than photosynthesis," says Beja. He added that his study "is the first to report fast photocycles with the so-called blue proteorhodopsins. This means both blue and green proteorhodopsins can act as proton pumps" to harvest energy because they contain proteorhodopsin. The authors also found some evidence suggesting that many of the bacteria with proteorhodopsin might be able to metabolize sulfur, a common energy source for deep-sea life. The marine bacteria might additionally be able to manufacture retinal, a molecule typically associated with vision.
The authors skimmed their bacteria samples from the top, or photic layer, of the Mediterranean and Red Seas. Since these bacteria cant survive typical lab conditions, the scientists inserted large segments of collected ocean bacterial DNA into host bacteria to create an amplified collection of the genome known as a large-insert bacterial artificial chromosome (BAC) library. To detect the gene segments of interest, the scientists used "specially designed PCR primers that can detect almost all proteorhodopsins reported today," Beja explains.
Many other organisms use proteins resembling proteorhodopsin for different functions. Humans, for instance, use rhodopsin to sense light in the eyeball. The presence of rhodopsin-like proteins in a wide range of life may eventually provide hints to the proteins evolutionary age. That this large class of transmembrane proteins was so well-conserved over a long evolutionary time scale provides evidence for complex ancient proteins. The new study also raises the question of whether bacteria use proteorhodopsin solely for energy transduction or also for sensory input as humans use rhodopsin.
Paul Ocampo | EurekAlert!
The most recent press releases about innovation >>>
Die letzten 5 Focus-News des innovations-reports im Überblick:
Mapping the interaction of a single atom with a single photon may inform design of quantum devices
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...