Washington Week: Student Voices (O)

Texas A&M researchers make virus discovery
By Vicky Flores
The Battalion, Texas A&M
June 15, 2009

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.

"The prophage (CP4-57) helps host to attach to the surface to form a biofilm, and also helps to generate diversity inside the biofilm community," Wang said.

Wang said she was drawn to this type of research because she is interested in finding out about nature and the changes that take place that we cannot see on the surface.

Biofilm research is pertinent to further discovery, Kim said.

"Biofilm formation is one of the new virulence factors for pathogenic bacteria. Therefore, this research will be associated with discovering the new target for inhibiting virulence produced by a number of pathogens," Kim said.

The discovery that the deletion of prophage-related genes seemed to induce biofilm was immediately recognized as a significant one by Wood, Kim said.

The process of a bacteria cell killing itself, using the virus fossils that it has retained, allows bacterium to build a biofilm in another place due to environment or temperature change.

In the future, Wood said he hopes to be able to use this research to help cure infections caused by these biofilms and to help clean the environment by a similar manipulation of the biofilms.

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