Uncovering secrets of natures primitive immune system
A team at Texas A&M University, led by Thomas Wood, has shed light on how bacteria have throughout the course of millions of years developed resistance to antibiotics by co- opting the DNA of their natural enemies – viruses.
According to Wood, the battle between bacteria and bacteria-eating viruses has been going on for millions of years, with viruses attempting to replicate themselves by – in one approach -invading bacteria cells and integrating themselves into the chromosomes of the bacteria.
When this happens a bacterium makes a copy of its chromosome, which includes the virus particle. The virus then can choose at a later time to replicate itself, killing the bacterium -similar to a ticking time bomb, he said.
However, things can go radically wrong for the virus because of random but abundant mutations that occur within the chromosome of the bacterium.
With this new diverse blend of genetic material, a bacterium not only overcomes the virus` lethal intentions but also flourishes at a greater rate than similar bacteria that have not incorporated viral DNA, say the scientists.
"Over millions of years, this virus becomes a normal part of the bacterium. It brings in new tricks, new genes, new proteins, new enzymes, new things that it can do. The bacterium learns how to do things from this.
"What we have found is that with this new viral DNA that has been trapped over millions of years in the chromosome, the cell has created a new immune system.
"It has developed new proteins that have enabled it to resists antibiotics and other harmful things that attempt to oxidise cells, such as hydrogen peroxide. These cells that have the new viral set of tricks don`t die or don`t die as rapidly," Wood said.