Issue date: 6/15/09 Section: News

Media Credit: Courtesy Photo [Click to enlarge]

By studying several proteins, chemical engineering professor Thomas Wood and postdoctoral chemical engineering research assistants Xiaoxue Wang and Younghoon Kim, have discovered that certain bacterium learn to take control of the genes of viruses.

Viruses are made mostly of protein and DNA and only live to inject their DNA, integrate into the chromosome, and then take over the cells functions and make the cell start working solely for the invading virus, Wood said.

As the cell continues to make hundreds of copies of its DNA it will very quickly wipe out the bacteria that it has invaded, Wood said.

E.coli has recently been sequenced and now its DNA is readable by scientists. Because E. coli has been sequenced, researchers are able to examine nine or 10 remnants of viruses that no longer function as a virus.

Usually a bacterium will lose genes that it no longer needs, but in this case the bacterium did not lose these leftover virus fossils, said Wood.

"If you look more closely we find out that the bacterium kept it because they have kept these tools that allow the cell to grow better," Woods said. "It holds onto these tools from its enemy."

These tools allow the cell to kill itself, Wood said. The purpose of this is to escape and protect itself.

"All of the [bacterium] are connected to each other by a polymer, DNA, sucrose or protein," Wood said, "and so in order for them to pack up and leave when conditions change, some of them have to die."

Another reason found for the bacterium to utilize virus DNA in order to kill itself is so when a virus attacks that particular cell it can kill itself off before the virus kills it.

"If it kills itself first then the virus won't make a hundred children to go kill a hundred more cells," Wood said.

Between a virus and a cell, constant mutating to attack and prevent attacks takes place.

From this research, Wood and his colleagues discovered that biofilm is related to bacterium by the ability to retain the DNA from viruses. A biofilm is bacterium that has formed together in a structure that is stronger in the number of bacteria cells.

Continued...

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