Bacteria growing in near darkness use a previously unknown process for harvesting energy and producing oxygen from sunlight, a research team led by a Penn State University scientist has discovered. The discovery lays the foundation for further research aimed at improving plant growth, harvesting energy from the Sun, and understanding dense blooms like those now occurring on Lake Erie and other lakes worldwide. A paper describing the discovery will be published in the Science Express edition of the journal Science on 21 August 2014.
"We have shown that some cyanobacteria, also called blue-green algae, can grow in far-red wavelengths of light, a range not seen well by most humans," said Donald A. Bryant, the Ernest C. Pollard Professor of Biotechnology and a professor of biochemistry and molecular biology at Penn State. "Most cyanobacteria can't 'see' this light either. But we have found a new subgroup that can absorb and use it, and we have discovered some of the surprising ways they manipulate their genes in order to grow using only these wavelengths," he said.
The scientists discovered that the cyanobacterial strain, named Leptolyngbya, completely changes its photosynthetic apparatus in order to use far-red light, which has wavelengths longer than 700 nanometers -- a little longer than the range of light that most people can see. The experiments by Bryant's team revealed that these cyanobacteria replace seventeen proteins in three major light-using complexes while also making new chlorophyll pigments that can capture the far-red light, and while using pigments called bilins in new ways. The scientists also discovered that the organisms accomplish this feat by quickly turning on a large number of genes to modify cellular metabolism and simultaneously turning off a large number of other genes -- a process that they have named Far-Red Light Photoacclimation (FaRLiP).
Because the genes that are turned on are the g
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