Featured Research

from universities, journals, and other organizations

Chameleon-like changes in world's most abundant phytoplankton

Date:
November 26, 2012
Source:
Indiana University
Summary:
Biologists have identified both the enzyme and molecular mechanism critical for controlling a chameleon-like process that allows one of the world's most abundant ocean phytoplankton, once known as blue-green algae, to maximize light harvesting for photosynthesis.

Cells of the cyanobacteria Synechococcus are true "chameleons of the sea," harvesting blue light offshore (orange cells) and green light in coastal waters (pink cells). Understanding the process has implications for climate change study and for the health care and biotechnology industries.
Credit: Image courtesy of Indiana University

An international team of biologists led by Indiana University's David M. Kehoe has identified both the enzyme and molecular mechanism critical for controlling a chameleon-like process that allows one of the world's most abundant ocean phytoplankton, once known as blue-green algae, to maximize light harvesting for photosynthesis.

Responsible for contributing about 20 percent of the total oxygen production on the planet, the cyanobacteria Synechococcus uses its own unique form of a sophisticated response called chromatic acclimation to fine tune the absorption properties of its photosynthetic antenna complexes to the predominant ambient light color. The researchers identified and characterized an enzyme, MpeZ, that plays a pivotal role in the mechanism that allows two different water-soluble proteins in Synechococcus -- phycoerythrin I and II -- to alter their pigmentation in order to maximize photon capture for photosynthesis.

Scientists want to understand how cyanobacteria optimize their photosynthetic activities in different light conditions to gain a better appreciation of how human activities affect the phytoplankton's ability to produce oxygen and uptake the greenhouse gas carbon dioxide, which they consume in order to grow. Science and industry also use the pigment-protein complex phycoerythrin for fluorescent imaging and as fluorescent markers in biotechnology and health care applications.

"We now have the ability to attach a novel chromophore, part of a molecule responsible for its color, to phycoerythrin, which provides a new chromophore-protein combination that absorbs and fluoresces at a wavelength that is not currently commercially available," said Kehoe, a professor in the IU Bloomington College of Arts and Sciences' Department of Biology. "Our results suggest that this new chromoprotein is brighter and more stable than most on the market today."

Kehoe also noted IU has begun the process of filing a patent on the invention. The team found that the gene encoding the MpeZ enzyme is activated in blue light. Once produced, MpeZ then binds to antenna proteins containing pigments that normally catch green light and attaches an alternative chromophore that allows the antennae to capture blue light. The specific mechanism, called type IV chromatic acclimation, involves replacing three molecules of the green light-absorbing chromophore with an equal number of blue light-absorbing chromophore. This color-shifting is reversible and is controlled by the ratio of blue to green light in the environment.

"These 'chromatic adapters' are true chameleons that can efficiently live in green coastal waters as well as in blue offshore waters by modifying their pigmentation," Kehoe said. "Synechococcus cells maintained in blue light harvest preferentially blue light, while cells grown in green light harvest more green."

Funding for this work came from the Agence Nationale Recherches in France, the European program MicroB3, IU's Office of International Programs, the National Science Foundation and the Lilly Foundation.


Story Source:

The above story is based on materials provided by Indiana University. Note: Materials may be edited for content and length.


Journal Reference:

  1. A. Shukla, A. Biswas, N. Blot, F. Partensky, J. A. Karty, L. A. Hammad, L. Garczarek, A. Gutu, W. M. Schluchter, D. M. Kehoe. Phycoerythrin-specific bilin lyase-isomerase controls blue-green chromatic acclimation in marine Synechococcus. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1211777109

Cite This Page:

Indiana University. "Chameleon-like changes in world's most abundant phytoplankton." ScienceDaily. ScienceDaily, 26 November 2012. <www.sciencedaily.com/releases/2012/11/121126163957.htm>.
Indiana University. (2012, November 26). Chameleon-like changes in world's most abundant phytoplankton. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2012/11/121126163957.htm
Indiana University. "Chameleon-like changes in world's most abundant phytoplankton." ScienceDaily. www.sciencedaily.com/releases/2012/11/121126163957.htm (accessed September 17, 2014).

Share This



More Earth & Climate News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Isolated N. Korea Asks For International Help With Volcano

Isolated N. Korea Asks For International Help With Volcano

Newsy (Sep. 16, 2014) Mount Paektu volcano in North Korea is showing signs of life and there's not much known about it. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins