Immunity; prokaryote viral immunity (Introduction)

by David Turell , Friday, August 28, 2020, 21:58 (1337 days ago) @ David Turell

A complex array of enzymes:

https://www.sciencemagazinedigital.org/sciencemagazine/28_august_2020/MobilePagedArticl...

"Bacteria and archaea are frequently attacked by viruses and other mobile genetic elements and rely on dedicated antiviral defense systems, such as restriction endonucleases and CRISPR, to survive. The enormous diversity of viruses suggests that more types of defense systems exist than are currently known. By systematic defense gene prediction and heterologous reconstitution, here we discover 29 widespread antiviral gene cassettes, collectively present in 32% of all sequenced bacterial and archaeal genomes, that mediate protection against specific bacteriophages. These systems incorporate enzymatic activities not previously implicated in antiviral defense, including RNA editing and retron satellite DNA synthesis. In addition, we computationally predict a diverse set of other putative defense genes that remain to be characterized. These results highlight an immense array of molecular functions that microbes use against viruses."

Comment: we use bacterial CRISPR enzyme to edit DNA, a perversion of its use in life, in which it is used to chop up enemy DNA's. But the real consideration is when does this type of immunity appear in relation to the origin of the organism? And it obviously has to be designed simultaneously into the first appearance of each new species..