Posted: February 29, 2008

Diatom research reveals possible climate solutions

(Nanowerk News) The research of tiny microscopic cells is changing the way people look at the environment and nanotechnology.
A diatom, whose name comes from the Greek word meaning “to cut in half,” is a type of unicellular alga. These diatoms are made of two parts held together by bands and are uniquely encased in a wall of silica resembling a cheese box.
“We use diatoms because they are a model organism for a particular process,” said Adrian Marchetti, a postdoctoral research associate at the Armbrust Lab, a biological oceanography lab at the UW. “We’re trying to look at their ability to influence global nutrient cycles.”
Diatoms have the ability to absorb carbon dioxide. They sink to the bottom of bodies of water, dragging carbon dioxide from the atmosphere with them.
“[Diatoms may be] anywhere from 240 [million years old] to even four to five hundred million years old,” Marchetti said.
Diatoms account for the same amount of carbon dioxide removal as all the rainforests combined, making them the “trees of the ocean,” said Thomas Mock, another postdoctoral researcher at the Armbrust Lab.
Before this research, only a handful of genes were known to create the diatom silica shell; Mock found more than 80 genes related to the cell walls. The genetic coding of these walls is uniquely important: If the walls get stickier, they sink and more carbon is drawn to the bottom, therefore reducing atmospheric carbon dioxide.
In order to understand better the genetic coding of these silica shells, Mock and his team are trying to identify certain proteins within the diatoms.
“If we can label these proteins, we can see if they are really going to the cell wall or not,” he said. “After this step, we would like to knock out these genes. If we do this, we can see how the phenotype would change.”
The implications of this research in the global warming epidemic are clear. If researchers are able to modify the silica shells of diatoms, it will be possible to make an even more efficient diatom, capable of capturing more carbon dioxide from the atmosphere.
“We found genes important for material scientists and engineers,” Mock said, explaining that scientists are interested in making structures similar to the silica wall. Silica is a compound close to silicon, a necessary item in the making of computer chips.
Diatoms are capable of making fine lines of silica, far finer than the current nanofabrication technology.
“We will be able to identify 150 genes for making nano-patterns,” Mock said. “Before, a maximum of 10 genes were known to create these nano-patterned cell walls.”
With this new research, computer chips can be made faster and more efficient, he said.
“The first diatom was sequenced in 2004, so we’ve only had three years to get the full blueprint of how diatoms are structured,” Marchetti said. “It’s fairly new.”
Mock said scientists must dig deeper into the function of the diatom’s genetics.
“At least 50 percent of these novel genes have no function at all,” he said. “The downside is that if you don’t know the function, you don’t know what you’re working with.”
Source: The Daily (Brittany Dennison)
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