Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Deep thinking: Scientists sequence a cold-loving marine microbe

26.07.2005


Colwellia psychrerythraea 34H reveals its subzero secrets

At home in the deep, dark Arctic Ocean, the marine bacterium Colwellia psychrerythraea 34H keeps very cool--typically below 5° degrees Celsius. How does the bacterium function in this frigid environment? To find out, scientists at The Institute for Genomic Research (TIGR) and collaborators have sequenced and analyzed C. psychrerythraea’s genome.

That genome analysis, posted in the Proceedings of the National Academy of Sciences (PNAS) Online Early Edition July 25-29, reveals key biochemical tools that cold-adapted, or psychrophilic, bacteria can use to survive in subzero temperatures. In particular, some of C. psychrerythraea’s estimated 4,937 genes apparently code for adaptive traits such as cell membranes packed with polyunsaturated fatty acids that resist freezing, polyester compounds that offer extra energy reserves, protective solutes inside cells, and ordinary enzymes altered to function in chilly seawater.



"Our goal was to compare C. psychrerythraea to a variety of bacteria that live at different optimal temperatures," remarks Barbara Methé, a molecular biologist at TIGR and lead author of the PNAS paper. "This organism must adapt to extreme cold--in fact, it cannot live above room temperature. How does it cope in such freezing conditions?"

Among cold-adapted bacteria, Colwellia species have a decidedly chilly comfort zone. The bacteria typically require temperatures less than 20° to grow. Scientists have found C. psychrerythraea--which prefers temperatures of -1° to 10° --hugging sediments along the Arctic floor, floating in the open ocean, and nestled inside Arctic and Antarctic sea ice.

To explain C. psychrerythraea’s unique cold-adapted chemistry, TIGR researchers and collaborators first sequenced the bacterium’s genome and analyzed its gene content for telltale proteins that might be cold-adaptive. Next, they predicted C. psychrerythraea’s proteome--or complete inventory of protein sequences--and then compared it to 21 predicted proteomes from known bacterial genomes. These included both mesophilic bacteria, which live at room temperature, and thermophilic bacteria, which thrive in ultra-hot environments.

Finally, the scientists overlaid key C. psychrerythraea protein sequences onto known 3D structures from similar proteins among the diverse bacteria. Like matching up blueprints, this strategy allowed the team to spot any striking distinctions in C. psychrerythraea’s amino acid composition, highlighting differences unique to the cold-loving organism.

Together, these analyses offer a picture of evolution in action, as C. psychrerythraea uses subtle tweaks in common bacterial biology to adapt to its chilly environs. For instance, the bacterium taps a group of four to five genes to generate polyunsaturated fatty acids and pack those acids into cell membranes, resulting in membranes that are fluid and functional--rather than a frozen chunk of biomass--below the freezing point. The genome also possesses a number of duplicated genes important to cell membrane biosynthesis. What’s more, C. psychrerythraea dresses in layers, generating plenty of extracellular polysaccharides (sugars) that coat cell membranes.

Aside from its cellular outerwear, C. psychrerythraea generates a range of potential cold-protective compounds. One example is a family of polyesters, known as polyhydroxyalkanoate (PHA) compounds, that may also boost reserves of nitrogen and carbon, which could be in short supply in the extreme cold. The organism also engineers cold-hardy versions of ordinary enzymes found in free-living bacteria, such as enzymes that break down organic matter. C. psychrerythraea possesses genes that may break down complex compounds, including pollutants, as well.

Collectively, Methé suggests, these subtle changes in biology allow C. psychrerythraea--and possibly similar bacteria--to thrive in the cold. More than just marvels of nature, cold-adapted enzymes hold industrial promise, as active ingredients in coldwater detergents, clean-up for industrial contaminants, and food treatments. Psychrophiles could hold clues to microbial life on other planets, as well, such as the frozen surface of Mars or one of Jupiter’s moons, Europa. As yet, however, there’s little chance that deciphering C. psychrerythraea’s genome will yield insights into another cool character, its namesake. Deming, who led the establishment of the Colwellia genus, named the genus after her one-time advisor: noted marine biologist Rita Colwell.

In addition the TIGR team, led by Methé, study collaborators include: Jody Deming of the University of Washington at Seattle; Bahram Momen of the University of Maryland at College Park; Adrienne Huston of Pennsylvania State University at University Park; and a team from the University of Maryland’s Center for Advanced Research in Biotechnology in Rockville.

Kathryn Brown | EurekAlert!
Further information:
http://www.tigr.org/

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

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...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

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...

Im Focus: Quantum Particles Form Droplets

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>