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: Life's extremists may be an untapped source of antibacterial drugs

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

Cohesin molecule safeguards cell division

18 hours ago

The cohesin molecule ensures the proper distribution of DNA during cell division. Scientists at the Research Institute of Molecular Pathology (IMP) in Vienna can now prove the concept of its carabiner-like ...

Nail stem cells prove more versatile than press ons

18 hours ago

There are plenty of body parts that don't grow back when you lose them. Nails are an exception, and a new study published in the Proceedings of the National Academy of Sciences (PNAS) reveals some of the r ...

Scientists develop 3-D model of regulator protein bax

20 hours ago

Scientists at Freie Universität Berlin, the University of Tubingen, and the Swiss Federal Institute of Technology in Zurich (ETH) provide a new 3D model of the protein Bax, a key regulator of cell death. When active, Bax ...

Researchers unwind the mysteries of the cellular clock

Nov 20, 2014

Human existence is basically circadian. Most of us wake in the morning, sleep in the evening, and eat in between. Body temperature, metabolism, and hormone levels all fluctuate throughout the day, and it ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.