Month: September 2022

PRION STRAINS. "Li has found that variation can creep into populations of initially identical prions. Their amino acid sequence stays the same but their already abnormal structures become increasingly twisted. These “mutant” forms have varying degrees of success in different environments. Some do well in brain tissue; others thrive in other types of cell. In each case, natural selection culls the least successful ones. The survivors pass on their structure to the “next generation”, by altering the folds of normal prion proteins." https://lnkd.in/dVZWBhV View in LinkedIn

INHERITED CHANGE. "This process follows the principles of Darwinian evolution, the same principles that shape the genetic material of viruses, bacteria and other living things. In DNA, mutations manifest as changes in the bases that line the famous double helix. In prions, mutations are essentially different styles of molecular origami. In both cases, they are selectively inherited and they can lead to adaptations such as drug resistance. In prions, it happens in the absence of any genetic material." https://lnkd.in/dVZWBhV View in LinkedIn

QUASI-ALIVE. "The remarkable finding that prions can mutate and adapt to their environment imbues them with a further attribute of living things, without however elevating them to the status of being ‘alive’." https://lnkd.in/dVZWBhV View in LinkedIn

ADAPTED STRAINS. "Li found that prions taken from brain tissue are different to those grown in cells cultured in a laboratory. The brain-adapted prions are capable of infected nerve tissue and they’re resistant to a drug called swainsonine (swa) that completely blocks the growth of other strains. The cell-adapted prions lack both these abilities but they’re better at growing in cell cultures." https://lnkd.in/dVZWBhV View in LinkedIn

SPONTANEOUS MUTANTS. "But mutants can arise out of the blue too. Even if a population consists entirely of the same strain (which you can set up through cloning), resistant or sensitive mutants develop spontaneously in a very short span of time. Prions, it seems, are very quick to adapt." https://lnkd.in/dVZWBhV View in LinkedIn

PRION EVOLUTION. "These shapes can evolve and adapt like lifeforms with DNA. As they 'replicate' by triggering shifts in other host prions there are an array of minor errors and changes, and in different conditions the best-suited shapes survive and multiply faster." https://lnkd.in/d4fjU7F View in LinkedIn

PROTO-LIFE. "Yet prions don’t reproduce the way living things do, using genetic material; they’re more like zombies in horror movies that turn their human victims into zombies as well. They’re not made up of cells, and they don’t have any kind of metabolism. Because they lack genetic material and a cellular structure, prions are less often grouped in with living things than viruses. https://lnkd.in/ddwhRte View in LinkedIn

PRION PROTEIN FOLDING, or its 3D structure, conveys enough information to change a normal cellular protein into an infectious prion particle. As such, it is a protein gene, a rather controversial concept. https://lnkd.in/e3uKvuP View in LinkedIn

LIVING PROTEIN? https://lnkd.in/d7w5k54 View in LinkedIn

BIOLOGY AS A TENDENCY. "As fuzzy logic theorist Bart Kosko has said: “biology is not destiny. It was never more than tendency. It was just nature’s first quick and dirty way to compute with meat. Chips are destiny.” https://lnkd.in/dTveM5M View in LinkedIn