Phages -- September 25, 2022

This was perhaps the most difficult book I read this summer:

Transformer: The Deep Chemistry of Life and Death, Nick Lane, c. 2022. 

Nick Lane is very, very good if you enjoy university-level biology and/or the origins of life. 

It was a difficult book to get through, but, wow, I was amply rewarded with the "Epilogue."

The "Epilogue" is go good, I re-typed it and placed it at this site.

Note: the author used "Brit spelling."

From that chapter:

Let me give you an example of how important this membrane potential is to bacteria. In the ocean there are about ten times as many viruses that attack bacteria (phages) as there are bacteria. You might have seen pictures of these viruses attaching themselves in droves to bacteria. Phages are remarkable, mechanical structures, like miniature lunar landeers, with the malevolence of H. G. Well's Martian tripods, anchoring themselves to the surface and injecting their DNA at high pressure into the soft body of the bacterium. Scores of them can line up like an invasion from outer space. 

The poor bacterial cell doesn't stand much chance, but it does have defences -- defences that we have recently learnt to exploit, called CRISPR, which allow for sophisticated gene editing. If the bacterium (or indeed its ancestors) has had an earlier exposure to the virus, it can recognise the viral DNA and marshal a counterattack, chopping up the DNA into bits before the virus can copy itself. But the time window is short. If there are too many phages, then there's only one way out for the bacterium: die, fast, for the good of its kin. How does it do this? It yanks open pores in its cell membrane, collapsing the electrical potential. It dies almost immediately, before the virus has a chance to copy itself and infect its sister cells. As a result of this sacrifice, at least some of its genes may live on in those sister cells -- the bacterial equivalent of us laying down our lives for family.

I first "saw" CGI of these viruses in my first year of graduate school decades ago and was blown away by what I saw.