Getting to know bacteria with 'multiple personalities'

Jul 07, 2011 By Jared Sagoff
Chains of cyanobacteria, also known as blue-green algae, produce oils which could be used for transportation fuels.

(PhysOrg.com) -- Cyanobacteria, or blue-green algae, have been the subject of decades of debate over exactly how they should be classified. While they reproduce and share DNA with their bacterial cousins, they are the only phylum of bacteria that can photosynthesize like plants.

"Scientists have long considered cyanobacteria to have 'multiple personalities,' as it were," said Andrzej Joachimiak, who directs the Structural Biology Center (SBC) at the U.S. Department of Energy's Argonne National Laboratory. "They are unique creatures in that they form key components of so many different ecological processes."

Joachimiak and his colleagues at the SBC, the NIH-funded Midwest Center for and the University of Chicago recently studied one particular phenomenon in cyanobacteria known as "heterocyst differentiation." Cyanobacteria cells group themselves into long that can contain dozens and even hundreds of cells—and like in humans, not all cyanobacteria cells are born the same. While most cyanobacteria cells aid in photosynthesis, occasionally a cell is produced that transforms atmospheric nitrogen into ammonia in a process known as "nitrogen fixation."

"Photosynthesis and nitrogen fixation are two of the most important and ubiquitous biochemical environmental processes that we know of," Joachimiak said. "If we can understand and manipulate how these bacteria differentiate themselves, we can better use natural pathways to mimic natural processes for a wide number of different applications, including the potential creation of biofuels."

Heterocyst differentiation is controlled in cyanobacteria by a special protein known as HetR, which recognizes and binds to specific region of the bacteria's DNA. The action of HetR, in turn, is mediated by inhibitors that control how often a photosynthetic cell turns into a nitrogen-fixing one.

In the long term, Joachimiak hopes that the SBC can synthesize and characterize inhibitors that can control how "switch." In order to do so, scientists have to use the high-energy X-rays provided by Argonne's Advanced Photon Source. In the research, a tightly focused X-ray beam was directed onto a small crystalline sample of HetR protein. The resulting pattern of scattered light enabled the researchers to identify the protein's structure.

The action of HetR is controlled by an action called dimer formation, wherein two separate HetRs join together to form a larger structure, which had not been observed before. This two-unit structure is what binds to the bacterium's DNA. Joachimiak said that he believes the HetR/ complex attracts other proteins that initiate cell .

Since its establishment in 1998, the SBC has contributed more than 3,250 separate structures to the Protein Data Bank, and SBC research has resulted in the publication of more than 1,100 scientific papers.

Explore further: Brand new technology detects probiotic organisms in food

Related Stories

Forest canopies help determine natural fertilization rates

May 29, 2008

In this week’s issue of Science, a team of researchers from the United States and Sweden report on a newly identified factor that controls the natural input of new nitrogen into boreal forest ecosystems. Nitrogen is the ...

Bacteria living on old-growth trees

Feb 23, 2011

A new study by Dr. Zoe Lindo, a post-doctoral fellow in the Department of Biology at McGill University, and Jonathan Whiteley, a doctoral student in the same department, shows that large, ancient trees may be very important ...

Bacteria on old-growth trees may help forests grow

Jun 07, 2011

A new study by Dr. Zoe Lindo, a post-doctoral fellow in the Department of Biology at McGill University, and Jonathan Whiteley, a doctoral student in the same department, shows that large, ancient trees may be very important ...

Recommended for you

Brand new technology detects probiotic organisms in food

4 hours ago

In the food industr, ity is very important to ensure the quality and safety of products consumed by the population to improve their properties and reduce foodborne illness. Therefore, a team of Mexican researchers ...

Protein evolution follows a modular principle

5 hours ago

Proteins impart shape and stability to cells, drive metabolic processes and transmit signals. To perform these manifold tasks, they fold into complex three-dimensional shapes. Scientists at the Max Planck ...

Report on viruses looks beyond disease

23 hours ago

In contrast to their negative reputation as disease causing agents, some viruses can perform crucial biological and evolutionary functions that help to shape the world we live in today, according to a new report by the American ...

User comments : 0