Bacterial immunity using self-destruction (Introduction)

by David Turell , Friday, January 10, 2020, 21:55 (1573 days ago) @ David Turell

Hit by a bacteriophage a bacterium self-distructs:

https://phys.org/news/2020-01-team-bacteria-self-destruct-viral-infections.html

"Researchers at University of California San Diego School of Medicine have discovered how a new immune system works to protect bacteria from bacteriophages (phages), viruses that specifically infect bacteria. This new system is unusual in that it works by abortive infection—the infected bacterial cell self-destructs to keep the infection from spreading to other cells.

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"One aspect of meiosis that particularly interests them is how a specific protein family, called HORMA proteins, help maintain the stability of the genome during this specialized cell division. But when a 2015 study published by National Institutes of Health bioinformaticians predicted that some bacteria might also produce HORMA proteins, and that these proteins might be involved in a new kind of immune system, Corbett was intrigued.

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"'Almost 75,000 different bacteria have had their genomes sequenced. Of those, Corbett said this new defense system is found in approximately 10 percent. His team cloned the system, now called CBASS, into a laboratory strain of E. coli that is usually sensitive to phage infection. "We were thrilled to find that CBASS provided nearly absolute immunity to phages," Corbett said.

"Digging deeper, the team went on to unravel a number of biochemical and structural details about the CBASS defense system, which contains several proteins. They found that the HORMA proteins sense the infection, then stimulate a second protein to synthesize a second messenger molecule. This molecule in turn activates a nuclease enzyme that destroys the bacterium's own genome, killing the cell and also keeping the phage from replicating and infecting other cells."

Comment: This presents a reproductive problem. It is logical to have cells take one for the group, but if they kill themselves, how do they reproduce new copies? The response might be some bacteria have the ability but pass it on by not being infected and killed. Fine but how did they learn the process if they never met the challenge? Looks designed to me.