 |
|
Researchers decode genetics of rare photosynthetic bacterium
February 11, 2008TEMPE, Ariz. - A bacterium that harvests far-red light by making a rare form of chlorophyll (chlorophyll d) has revealed its genetic secrets, according to a team of researchers who recently sequenced the bacteria's genome.
The researchers, from Arizona State University and Washington University, St. Louis, report in the current online edition (Feb. 4) of the Proceedings of the National Academy of Sciences, that they have sequenced the genome of the cyanobacterium, Acaryochloris marina, which through its production of chlorophyll d can absorb "red edge," near infrared long wavelength light -- light that is invisible to the naked eye. Acaryochloris marina has a massive genome (8.3 million base pairs) and is among the largest of 55 cyanobacterial strains in the world. It is the first chlorophyll-d containing organism to be sequenced.
The advance has applications in plant research, said Jeffrey Touchman, an assistant professor ASU's School of Life Sciences and lead author of the paper, "Niche adaptation and genome expansion in the chlorophyll d-producing cyanobacterium Acaryochloris marina."
"Chlorophyll d harvests light from a spectrum of light that few other organisms can, and that enables this organism to carve out its own special niche in the environment to pick up far-red light," Touchman explained. "The agricultural implications could be significant. One could imagine the transfer of this biochemical mechanism to other plants where they could then use a wider range of the light spectrum and become sort of 'plant powerhouses,' deriving increased energy by employing this new photosynthetic pigment."
There is a bioenergy link to this work, said Touchman, who is a member of ASU's Center for Bioenergy and Photosynthesis. It could be used for crops that are turned into fuels or to generate biomass.
Touchman worked with Robert Blankenship of Washington University on the sequencing project, which involved collaborators from Australia and Japan. Touchman also has an appointment with Translational Genomics Research Institute (TGen), Scottsdale, Ariz., where he operates a high-throughput DNA sequencing facility. The work is supported by the National Science Foundation.
Blankenship said with every gene of Acaryochloris marina now sequenced and annotated, the immediate goal is to find the enzyme that causes a chemical structure change in chlorophyll d, making it different from the more common chlorophyll a, and b, but also from about nine other forms of chlorophyll.
"The synthesis of chlorophyll by an organism is complex, involving 17 different steps in all," Blankenship said. "Someplace near the end of this process, an enzyme transforms a vinyl group to a formyl group to make chlorophyll d. This transformation of chemical forms is not known in any other chlorophyll molecules."
Touchman and Blankenship said they have some candidate genes they will test. They plan to insert these genes into an organism that only makes chlorophyll a. If the organism learns to synthesize chlorophyll d with one of the genes, the mystery of chlorophyll d synthesis will be solved, and then the excitement will begin.
The researchers said harvesting solar power through plants or other organisms that would be genetically altered with the chlorophyll d gene could make them "solar power factories" that generate and store solar energy. Consider a seven-foot tall corn plant genetically tailored with the chlorophyll d gene to be expressed at the very base of the stalk. While the rest of the plant synthesized chlorophyll a, absorbing short wave light, the base is absorbing "red edge" light in the 710 nanometer range.
Energy could be stored in the base without competing with any other part of the plant for photosynthesis, as the rest only makes chlorophyll a. Also, the altered corn using the chlorophyll d gene could become a super plant because of its enhanced ability to harness energy from the Sun.
That model is similar to how Acaryochloris marina actually operates in the South Pacific, specifically Australia's Great Barrier Reef. Discovered just 11 years ago, the cyanobacterium lives in a symbiotic relationship with a sponge-like marine animal popularly called a sea squirt. The Acaryochloris marina lives beneath the sea squirt, which is a marine animal that lives attached to rocks just below the surface of the water. The cyanobacterium absorbs "red edge" light through the tissues of the sea squirt.
The genome, said Blankenship, is "fat and happy. Acaryochloris marina lies down there using far red light that no one else can use. The organism has never been under very strong selection pressure to maintain a modest genome size. It's in kind of a sweet spot. Living in this environment is what allowed it to have such dramatic genome expansion."
Touchman said that once the gene that causes the late-step chemical transformation is found and inserted successfully into other plants or organisms, that it could potentially represent a five percent increase in available light for organisms to use.
"We now have the complete genetic information of a novel organism that makes this type of pigment that no other organism does," he said. "We don't yet know what every gene does, but this presents a fertile area for future studies. When we find the chlorophyll-d enzyme and then look into transferring it into other organisms, we'll be working to extend the range of potentially useful radiation from our Sun."
Arizona State University
"Chlorophyll d harvests light from a spectrum of light that few other organisms can, and that enables this organism to carve out its own special niche in the environment to pick up far-red light," Touchman explained. "The agricultural implications could be significant. One could imagine the transfer of this biochemical mechanism to other plants where they could then use a wider range of the light spectrum and become sort of 'plant powerhouses,' deriving increased energy by employing this new photosynthetic pigment."
There is a bioenergy link to this work, said Touchman, who is a member of ASU's Center for Bioenergy and Photosynthesis. It could be used for crops that are turned into fuels or to generate biomass.
Touchman worked with Robert Blankenship of Washington University on the sequencing project, which involved collaborators from Australia and Japan. Touchman also has an appointment with Translational Genomics Research Institute (TGen), Scottsdale, Ariz., where he operates a high-throughput DNA sequencing facility. The work is supported by the National Science Foundation.
Blankenship said with every gene of Acaryochloris marina now sequenced and annotated, the immediate goal is to find the enzyme that causes a chemical structure change in chlorophyll d, making it different from the more common chlorophyll a, and b, but also from about nine other forms of chlorophyll.
"The synthesis of chlorophyll by an organism is complex, involving 17 different steps in all," Blankenship said. "Someplace near the end of this process, an enzyme transforms a vinyl group to a formyl group to make chlorophyll d. This transformation of chemical forms is not known in any other chlorophyll molecules."
Touchman and Blankenship said they have some candidate genes they will test. They plan to insert these genes into an organism that only makes chlorophyll a. If the organism learns to synthesize chlorophyll d with one of the genes, the mystery of chlorophyll d synthesis will be solved, and then the excitement will begin.
The researchers said harvesting solar power through plants or other organisms that would be genetically altered with the chlorophyll d gene could make them "solar power factories" that generate and store solar energy. Consider a seven-foot tall corn plant genetically tailored with the chlorophyll d gene to be expressed at the very base of the stalk. While the rest of the plant synthesized chlorophyll a, absorbing short wave light, the base is absorbing "red edge" light in the 710 nanometer range.
Energy could be stored in the base without competing with any other part of the plant for photosynthesis, as the rest only makes chlorophyll a. Also, the altered corn using the chlorophyll d gene could become a super plant because of its enhanced ability to harness energy from the Sun.
That model is similar to how Acaryochloris marina actually operates in the South Pacific, specifically Australia's Great Barrier Reef. Discovered just 11 years ago, the cyanobacterium lives in a symbiotic relationship with a sponge-like marine animal popularly called a sea squirt. The Acaryochloris marina lives beneath the sea squirt, which is a marine animal that lives attached to rocks just below the surface of the water. The cyanobacterium absorbs "red edge" light through the tissues of the sea squirt.
The genome, said Blankenship, is "fat and happy. Acaryochloris marina lies down there using far red light that no one else can use. The organism has never been under very strong selection pressure to maintain a modest genome size. It's in kind of a sweet spot. Living in this environment is what allowed it to have such dramatic genome expansion."
Touchman said that once the gene that causes the late-step chemical transformation is found and inserted successfully into other plants or organisms, that it could potentially represent a five percent increase in available light for organisms to use.
"We now have the complete genetic information of a novel organism that makes this type of pigment that no other organism does," he said. "We don't yet know what every gene does, but this presents a fertile area for future studies. When we find the chlorophyll-d enzyme and then look into transferring it into other organisms, we'll be working to extend the range of potentially useful radiation from our Sun."
Arizona State University
Chlorophyll Current Events and Chlorophyll News RSSU.Va. Engineers Aim to Solve 'Burning' Computer Problem
f you've balanced a laptop computer on your lap lately, you probably noticed a burning sensation. That's because ever-increasing processing speeds are creating more and more heat, which has to go somewhere -- in this case, into your lap.
Climate change causing significant shift in composition of coastal fish communities
A detailed analysis of data from nearly 50 years of weekly fish-trawl surveys in Narragansett Bay and adjacent Rhode Island Sound has revealed a long-term shift in species composition, which scientists attribute primarily to the effects of global warming.
Berkeley Researchers Identify Photosynthetic Dimmer Switch
In a study of the molecular mechanisms by which plants protect themselves from oxidation damage should they absorb too much sunlight during photosynthesis, a team of researchers has discovered a molecular "dimmer switch" that helps control the flow of solar energy moving through the system of light harvesting proteins.
ESA contributes to ocean carbon cycle research
The Earth's oceans play a vital role in the carbon cycle, making it imperative that we understand marine biological activity enough to predict how our planet will react to the extra 25 000 million tonnes of carbon dioxide humans are pumping into the atmosphere annually.
Global Warming Affects World's Largest Freshwater Lake
Russian and American scientists have discovered that the rising temperature of the world's largest lake, located in frigid Siberia, shows that this region is responding strongly to global warming.
Research Team Is First to Model Photochemical Compass for Bird Navigation
A team of researchers at Arizona State University and the University of Oxford are the first to model a photochemical compass that may simulate how migrating birds use light and Earth's weak magnetic field to navigate.
Scientists discover new ocean current
Scientists at Georgia Tech have discovered a new climate pattern, the North Pacific Gyre Oscillation. This pattern explains, for the first time, changes in the water important in helping commercial fishermen understand fluctuations in the fish stock. They're also finding that as the Earth is warming, large fluctuations in these factors could help climatologists predict how oceans will respond in a warmer world.
How Iron Gets into the North Pacific
Most oceanographers have assumed that, in the areas of the world's oceans known as High Nutrient, Low Chlorophyll (HNLC) regions, the iron needed to fertilize infrequent plankton blooms comes almost entirely from wind-blown dust.
Researchers visualize complex pigment mixtures in living cells
In a technical advance that could allow researchers to watch cells as they act during the process of photosynthesis, scientists have developed a method that extends the power of fluorescence-mediated bio-imaging to see discrete pigments inside live cells of bacteria.
Bacterium sequenced makes rare form of chlorophyll
Researchers at Washington University in St. Louis and Arizona State University have sequenced the genome of a rare bacterium that harvests light energy by making an even rarer form of chlorophyll, chlorophyll d. Chlorophyll d absorbs "red edge," near infrared, long wave length light, invisible to the naked eye.
More Chlorophyll Current Events and Chlorophyll News Articles
 | Chlorophyll a Fluorescence : A Signature of Photosynthesis (Advances in Photosynthesis and Respiration) (Advances in Photosynthesis and Respiration) Chlorophyll a Fluorescence: A Signature of Photosynthesis highlights chlorophyll (Chl) a fluorescence as a convenient, non-invasive, highly sensitive, rapid and quantitative probe of oxygenic photosynthesis. Thirty-one chapters, authored by 58 international experts, provide a solid foundation of the basic theory, as well as of the application of the rich information contained in the Chl a... |
 | Chlorophylls and Bacteriochlorophylls (Advances in Photosynthesis and Respiration) by Bernhard Grimm Chlorophylls are the most obvious natural pigments on Earth where they can be observed even from satellites in outer space: they also sustain life on Earth through their involvement in photosynthesis. With 37 concise chapters, this book reviews recent progress and current status of studies of the chemistry, metabolism and spectroscopy of chlorophylls and chlorophyll-protein complexes. Also... |
| Comfrey and chlorophyll by Vincent Licata | |
| Chlorophyll Magic From Living Plant Life by Bernard Jensen | |
 | Chlorella, The Ultimate Green Food: Nature's Richest Source of Chlorophyll, DNA and RNA (Health Learning Handbook) by Beth M. Ley Chlorella is the ultimate green food. This green algea is nature's richest source of chlorophyll, DNA & RNA. Chlorella provides a very well-balanced package of essential nutrients. Along with its rich stores of complete protein, Chlorella also provides essential fatty acids, carbohydrates, minerals, vitamins, enzymes, chlorophyll, RNA/DNA, antioxidants, special fiber and its own unique... |
| The Healing power of Chlorophyll from plant life by Bernard Jensen | |
| The Healing Power of Chlorophyll (Magic Survival Kit) by Bernard Jensen | |
 | Applications of Chlorophyll Fluorescence: In Photosynthesis Research, Stress Physiology, Hydrobiology and Remote Sensing |
| Chlorophyllfluoreszenz in der Ökologie (Applications of chlorophyll fluorescence in ecology) by D. Ernst | |
| Chlorophyll, Nature's "Green Magic" by Theodore M. PhD. Rudolph |
| © 2008 BrightSurf.com |