6th February, 2018: Phages, a kind of viruses are dangerous
for bacteria; they can infect and kill bacteria. Naturally, bacteria have
developed mechanisms to defend themselves against viral attacks. Scientists of University
of California, USA, have recently identified such mechanisms adopted by
bacteria against viral attacks. They have identified ten sets of bacterial
genes, which have roles of defending against viruses, as per the study
published in Science recently.
The current discovery “probably more than doubles the number of immune systems known in bacteria,” says Joseph Bondy-Denomy, a microbiologist at the University of California.
During viral infection, phages usually hijack bacteria’s genetic machinery and force them to produce viral DNA instead. Some bacteria are smart enough to store the pieces of past invader’s DNA so that they could recognize and fend off those phages in the future. This amounts to only 40% of the total bacteria. What are the defense mechanisms of the rest of bacteria? This was the question triggered the current research.
Researchers sifted through genetic information from about 45,000 microbes from far and wide, including from the bottom of the sea, to identify their defense mechanism against virus. Researchers found that nine groups of bacterial genes actually had antiphage defense system. One other gene protected bacteria against plasmids, another source of foreign DNA in bacteria. Some of the genes so identified were contained fragments of DNA that are also known to be an important part of the innate immune system in plants, mammals and invertebrates.
The newly identified genes are named after deities like Zorya, a pair of goddesses from Slavic mythology.
Researchers believe that their results will trigger further studies and would lead to the development of novel tools for defense against viruses in biotechnology.