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      Human cells hacked to act like squid skin cells could unlock key to camouflage

      news.movim.eu / ArsTechnica · Tuesday, 28 March, 2023 - 17:18 · 1 minute

    Certain squid have the ability to camouflage themselves by making themselves transparent and/or changing their coloration.

    Enlarge / Certain squid have the ability to camouflage themselves by making themselves transparent and/or changing their coloration. (credit: YouTube/KQED Deep Look )

    Certain cephalopods like cuttlefish, octopuses, and squid have the ability to camouflage themselves by making themselves transparent and/or changing their coloration. Scientists would like to learn more about the precise mechanisms underlying this unique ability, but it's not possible to culture squid skin cells in the lab. Researchers at the University of California, Irvine, have discovered a viable solution: replicating the properties of squid skin cells in mammalian (human) cells in the lab. They presented their research at a meeting of the American Chemical Society being held this week in Indianapolis.

    "In general, there's two ways you can achieve transparency," UC Irvine's Alon Gorodetsky, who has been fascinated by squid camouflage for the last decade or so, said during a media briefing at the ACS meeting. "One way is by reducing how much light is absorbed—pigment-based coloration, typically. Another way is by changing how light is scattered, typically by modifying differences in the refractive index." The latter is the focus of his lab's research.

    Squid skin is translucent and features an outer layer of pigment cells called chromatophores that control light absorption. Each chromatophore is attached to muscle fibers that line the skin's surface, and those fibers, in turn, are connected to a nerve fiber. It's a simple matter to stimulate those nerves with electrical pulses, causing the muscles to contract. And because the muscles pull in different directions, the cell expands, along with the pigmented areas, which changes the color. When the cell shrinks, so do the pigmented areas.

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      Engineering a second genetic code in parallel with the normal one

      Diana Gitig · news.movim.eu / ArsTechnica · Friday, 27 August, 2021 - 18:59 · 1 minute

    A cartoon of the process that translates the genetic code in DNA into a protein.

    Enlarge / A cartoon of the process that translates the genetic code in DNA into a protein. (credit: BSIP / Getty Images )

    All living things on Earth use a version of the same genetic code. Every cell makes proteins using the same 20 amino acids. Ribosomes, the protein-making machinery within cells, read the genetic code from a messenger RNA molecule to determine which amino acid to put next into the particular protein they are building.

    This code is universal, which is why the ribosomes in our cells can read a piece of viral messenger RNA and make a functional viral protein from it. There are plenty of other amino acids, though. While life does not generally use them, scientists have been incorporating these into proteins. Now, researchers have figured out a way to greatly expand the genetic code, allowing widespread incorporation of these non-biological amino acids. They accomplish this by running a second set of everything—proteins and RNAs—needed to translate the genetic code.

    A system apart

    Non-canonical amino acids can serve a number of functions. They can act as labels so a researcher’s particular protein of interest can more easily be tracked within cells. They can help to regulate a protein’s function, allowing researchers to activate and inactivate it at a specific time and place of their choosing and then observe the downstream effects. If enough of these non-canonical amino acids are strung together, the resulting proteins would constitute an entirely new class of biopolymers that might carry out functions that traditional proteins cannot—for research, therapeutic, or other purposes.

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      A mildly insane idea for disabling the coronavirus

      John Timmer · news.movim.eu / ArsTechnica · Saturday, 28 November, 2020 - 17:06 · 1 minute

    Colorful blobs cluster together like a bunch of grapes.

    Enlarge / Diagram of the structure of the virus' spike protein. (credit: McLellan Lab, University of Texas at Austin )

    When the COVID-19 pandemic was first recognized for the threat that it is, researchers scrambled to find anything that might block the virus' spread. While vaccines have grabbed much of the attention lately, there was also the hope that we could develop a therapy that would block the worst effects of the virus. Most of these have been extremely practical: identify enzymes that are essential for the virus to replicate, and test drugs that block similar enzymes from other viruses. These drugs are designed to be relatively easy to store and administer and, in some cases, have already been tested for safety in humans, making them reasonable choices for getting something ready for use quickly.

    But the tools we've developed in biotechnology allow us to do some far less practical things, and a paper released today describes how they can be put to use to inactivate SARS-CoV-2. This is in no way a route to a practical therapy, but it does provide a fantastic window into what we can accomplish by manipulating biology.

    Throw it in the trash

    The whole effort described in the new paper is focused on a simple idea: if you figure out how to wreck one of the virus' key proteins, it won't be able to infect anything. And, conveniently, our cells have a system for destroying proteins, since that's often a useful thing to do. In some cases, the proteins that are destroyed are damaged; in others, the proteins are made and destroyed at elevated paces to allow the cell to respond to changing conditions rapidly. In a few cases, changes in the environment or the activation of signaling pathways can trigger widespread protein destruction, allowing the cell to quickly alter its behavior.

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