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Thread: Origin of life status

  1. #121
    tWebber TheLurch's Avatar
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    Quote Originally Posted by lee_merrill View Post
    Did you notice this, though?

    Source:

    We find that the last universal common ancestor of cellular life (LUCA) predated the end of late heavy bombardment (>3.9 Ga)

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    Though they say that the late heavy bombardment would not have sterilized the planet, this indicates that life got an early start, under hostile conditions, even.
    Yes, if you had bothered to read my post, you'd have seen i quoted that exact bit of information.

    Agreed it started early relative to the total history of the earth. But it's still a staggering amount of time, especially when you consider how fast favorable chemical reactions can occur.
    "Any sufficiently advanced stupidity is indistinguishable from trolling."

  2. #122
    tWebber lee_merrill's Avatar
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    Quote Originally Posted by TheLurch View Post
    Yes, if you had bothered to read my post, you'd have seen i quoted that exact bit of information.
    The part I was interested in was "We find that the last universal common ancestor of cellular life (LUCA) predated the end of late heavy bombardment", not the 3.9 that you quoted, though.

    Agreed it started early relative to the total history of the earth. But it's still a staggering amount of time, especially when you consider how fast favorable chemical reactions can occur.
    Hubert Yockey would disagree! But maybe we'll leave it at that, unless you're willing to buy his paper.

    Blessings,
    Lee
    "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

  3. #123
    tWebber TheLurch's Avatar
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    Quote Originally Posted by lee_merrill View Post
    Hubert Yockey would disagree!
    And we should all listen to a non biologist who wrote 50 years ago when it came to this topic, obviously.
    "Any sufficiently advanced stupidity is indistinguishable from trolling."

  4. Amen shunyadragon, Roy, Seeker amen'd this post.
  5. #124
    tWebber shunyadragon's Avatar
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    Quote Originally Posted by lee_merrill View Post
    No, this is a thread on the status of origin-of-life research, and I'll let people draw their own conclusions.

    Blessings,
    Lee
    This references by Tour and Yockey do not reflect the status ot the origin of life research.
    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

  6. #125
    tWebber shunyadragon's Avatar
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    Source: https://phys.org/news/2019-07-life-insight-peptides-amino-acids.html



    Origin of life insight: peptides can form without amino acids

    Peptides, one of the fundamental building blocks of life, can be formed from the primitive precursors of amino acids under conditions similar to those expected on the primordial Earth, finds a new UCL study.


    The findings, published in Nature, could be a missing piece of the puzzle of how life first formed.

    "Peptides, which are chains of amino acids, are an absolutely essential element of all life on Earth. They form the fabric of proteins, which serve as catalysts for biological processes, but they themselves require enzymes to control their formation from amino acids," explained the study's lead author, Dr. Matthew Powner (UCL Chemistry).

    "So we've had a classic chicken-and-egg problem—how were the first enzymes made?"

    He and his team have demonstrated that the precursors to amino acids, called aminonitriles, can be easily and selectively turned into peptides in water, taking advantage of their own built-in reactivity with the help of other molecules that were present in primordial environments.

    "Many researchers have sought to understand how peptides first formed to help life develop, but almost all of the research has focused on amino acids, so the reactivity of their precursors was overlooked," said Dr. Powner.

    The precursors, aminonitriles, require harsh conditions, typically strongly acidic or alkaline, to form amino acids. And then amino acids must be recharged with energy to make peptides. The researchers found a way to bypass both of these steps, making peptides directly from energy-rich aminonitriles.

    They found that aminonitriles have the innate reactivity to achieve peptide bond formation in water with greater ease than amino acids. The team identified a sequence of simple reactions, combining hydrogen sulfide with aminonitriles and another chemical substrate ferricyanide, to yield peptides.

    "Controlled synthesis, in response to environmental or internal stimuli, is an essential element of metabolic regulation, so we think that peptide synthesis could have been part of a natural cycle that took place in the very early evolution of life," said Pierre Canavelli, the first author of the study who completed it while at UCL.

    The molecules that served as substrates to help the formation of the amide bonds in the experiments are outgassed during volcanism and are all likely to have been present on the early Earth.

    "This is the first time that peptides have been convincingly shown to form without using amino acids in water, using relatively gentle conditions likely to be available on the primitive Earth," said co-author Dr. Saidul Islam (UCL Chemistry).

    The findings may also be useful to the field of synthetic chemistry, as amide bond formation is essential for many commercially important synthetic materials, bioactive compounds and pharmaceuticals. The method used in this study is chemically unconventional but follows a pathway to ligate (join together) peptides that mimics biological processes, unlike peptide-building pathways more commonly used in chemistry laboratories that run in the opposite direction and require expensive and wasteful reagents.

    The research team is furthering their studies by searching for other pathways to peptides using aminonitriles, and investigating the functional properties of the peptides that their experiments have produced, to better understand how they could have helped kick start life 4 billion years ago.

    Explore further

    Artificial peptide bond formation provides clues to creation of life on Earth
    More information: Peptide ligation by chemoselective aminonitrile coupling in water, Nature (2019). DOI: 10.1038/s41586-019-1371-4 , https://nature.com/articles/s41586-019-1371-4
    Journal information: Nature

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    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

  7. #126
    tWebber shunyadragon's Avatar
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    Source: https://www.extremetech.com/extreme/299610-enceladus-deep-ocean-contains-basic-building-blocks-of-life



    Enceladus’ Deep Ocean Contain's Basic Building Blocks of Life

    Enceladus_geysers
    Geyers erupting from Enceladus. Credit: NASA

    Last year, some of the same research team reported finding complex organic macromolecules within the water vapor that were likely floating on the surface of Enceladus’ ocean. This year, they followed up with a more sophisticated analysis of what sorts of molecules were dissolved into the ocean water. The compounds found within Enceladus’ water vapor plumes, which are responsible for most of the content of Saturn’s E ring, are believed to be present in the liquid subsurface ocean that exists underneath the south pole rather than being the result of contamination as the water escapes from its subsurface prison. That’s significant because many of the nitrogen and oxygen-based compounds the researchers detected are also essential to amino acids here on Earth.

    Abiogenesis is the process by which life arises from non-living matter, beginning with the presence of simple organic compounds. While there are those who argue that life might not have arisen on Earth but instead arrived here from elsewhere, this really just kicks the can down the road. Life, wherever it came from, had to evolve from non-life at some point. Since the 1950s, we’ve known that amino acids can be synthesized from inorganic compounds under conditions intended to replicate the early Earth. The discovery of so-called “black smokers” (undersea vents in the seafloor) and the Lost City hydrothermal vent system in 2000 both illustrated how life could arise without the need for photosynthesis. Black smokers are rich areas of life, while the Lost City hydrothermal vent system is rich in abiotically produced methane and hydrogen — two materials fundamental to life.

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    The nitrogen and oxygen compounds found within the water vapor indicate that some of these same processes are active within Enceladus as well, and therefore imply that its subsurface ocean contains the ingredients required for the formation of life. The detected compounds were initially dissolved in the oceans of Enceladus before evaporating and condensing on the surface of the moon. When the moon began emitting jets of water, the compounds were carried skyward and into Cassini’s path.

    Enceladus-Plumes

    “If the conditions are right, these molecules coming from the deep ocean of Enceladus could be on the same reaction pathway as we see here on Earth,” said Nozair Khawaja, who led the research team of the Free University of Berlin. “We don’t yet know if amino acids are needed for life beyond Earth, but finding the molecules that form amino acids is an important piece of the puzzle.” Khawaja’s findings were published Oct. 2 in the Monthly Notices of the Royal Astronomical Society.

    There’s still a great deal we don’t know about Enceladus. The reason it periodically emits jets of water is related to the mechanisms that keep the water liquid. As the moon orbits Saturn, tidal flexing from Saturn and other moons may generate enough energy to allow the planet’s water reserves to remain liquid. The ridges at the South Pole from which water escapes are thought to fill with ice when the planet is under comparatively little stress, then flex open once more as its orbit changes. But the tidal flexing of Enceladus isn’t thought to generate enough energy to account for the liquid ocean Cassini observed — only about 1.1GW of energy is thought to be produced, whereas ~4.7GW is required to generate the effects we observe. Radionuclide decay within the core is also unlikely; Enceladus may have been hot enough to maintain a liquid ocean using radionuclide heating early in its existence, but the short-lived elements that powered this reaction will have decayed by now. Investigations into how Enceladus’ vast subsurface ocean remains liquid are ongoing.

    One big difference between how Enceladus was viewed when I was a kid versus now is the chance that the moon could harbor life. While Mars may still possess a subglacial lake, and water is theorized to exist on Ganymede and under the ice sheets of Europa, we know it exists under the surface of Enceladus as well, which might make it the best environment to search for signs of life. Multiple follow-up missions to the planet are under study and it may one day be targeted for an exploratory mission in its own right.

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    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

  8. #127
    tWebber shunyadragon's Avatar
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    Source: https://www.csmonitor.com/Science/2015/0623/How-can-life-emerge-from-nonliving-matter-UNC-scientists-find-new-evidence



    How can life emerge from nonliving matter? UNC scientists find new evidence.

    Researchers say new findings could help answer questions about life’s chemical origins.

    June 23, 2015

    By Joseph Dussault Staff writer
    @josephdussault
    A recipe for the perfect, life-yielding, primordial soup has eluded science for decades. But a team of biochemists say they now have a key ingredient.

    Charles Carter and Richard Wolfenden, both of the University of North Carolina, have uncovered new evidence of abiogenesis, the process by which life arises from non-living chemical matter. Their study, published Thursday in the Journal of Biological Chemistry, suggests that a single ancient gene may have used each of its opposite DNA strands to code for different chemical catalysts. Those separate catalysts would have both activated amino acids, which then formed proteins – essential to the production of living cells.

    Where does life come from? Despite years of research, scientists still rack their brains over this most existential question. If the universe did begin with a rapid expansion, per the Big Bang theory, then life as we know it sprung from nonliving matter. How this process, known as abiogenesis, could have occurred is a source of much scientific debate.

    In the early 20th century, the “primordial soup” model of abiogenesis started to gain traction. It proposes that in Earth’s prebiotic history, simple organic matter was exposed to energy in the form of volcanoes and electrical storms. That energy would have catalyzed chemical reactions that, in the span of a few hundred million years, could have produced self-replicating molecules.

    In 1952, Stanley Miller and Harold Urey tested that hypothesis. They combined water, methane, ammonia, and hydrogen in sealed vials in attempt to replicate Earth’s original atmosphere. They bombarded the vials with heat and continuous electrode sparks to simulate volcanic activity and lightening. Eventually, the reaction produced a number of amino acids – the building blocks of proteins and, by extension, life itself.

    Today, the Miller-Urey experiment is contested for a number of reasons, including the possibility that Earth’s original atmosphere may have had a different composition. Still, the production of organic compounds from inorganic “precursors” laid a strong foundation for the primordial soup hypothesis. And new findings support that hypothesis, Dr. Carter says.

    “Our work furnishes a likely explanation for how nature overcame one of the main obstacles in turning the building blocks, demonstrated by Miller, into genetic coding and inheritance,” Carter explains.

    The obstacle Carter refers to is the fact that certain chemical reactions, essential to spontaneous protein assembly, occur very slowly. Unless they are sped up and regulated, the prospect of life becomes all but impossible. In modern living cells, that reaction is catalyzed by enzymes called aminoacyl-tRNA synthetases. These complex molecules belong to two separate families, or classes. Class I synthetases activate 10 of the 20 amino acids that form proteins. Class II synthetases activate the other 10.

    In their experiments, Carter and colleagues took modern synthetases and stripped away all but their essential and universal components. They found that the remaining structure, which they call “Urzymes,” were actually functional. These Urzymes probably resemble the ancestral molecules which eventually gave way to life, Carter says.

    “We discovered Urzymes within the elaborate modern aminoacyl-tRNA synthetases by ignoring all the bells and whistles created by evolution,” Carter says. “We showed that what was left was fully capable of translating the code.”

    According to Carter, the genetic code itself is strangely organized. One coding strand forms the outer surface of the protein, while the other forms the core. In other words, the two strands rely on “inside-out” interpretations of the same genetic information.

    “We devised a way to show experimentally that the two families are related to each other, despite all evidence to the contrary,” Carter says. “Our experiment shows that the ancestral Class II protozyme was built from exactly the same blueprint as the ancestral Class I protozyme, only the blueprint behaved as if it were written on glass and interpreted from the opposite side. The stunning thing is that both interpretations work equally well in the test tube.”

    In other words, nature solved the protein production problem by evolving a single gene to do two separate jobs. And while Carter and Dr. Wolfenden’s study leaves many questions unanswered, it does provide a “new set of tools” with which to move forward. Carter says his work could inform new experiments to “fill the gaps” in prebiotic chemistry.

    Existential implications aside, there is another motivation for answering the abiogenesis question. If we fully understand which materials and conditions are necessary to the production of life, we can narrow our search for life elsewhere in the cosmos. In other words, a primordial soup recipe could revolutionize the study of astrobiology.

    “I myself am an inveterate ‘terrestrial chauvinist,’” Carter says. “I believe that life as we know it involves so many enchanting coincidences that it is both unique and inevitable, given appropriate environments. My point of view is probably an outlier, but it is based on my life trying to understand what makes biochemistry tick and discovering just how well-suited so many of nature’s choices really are.”

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    Last edited by shunyadragon; 03-20-2020 at 05:56 AM.
    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

  9. #128
    tWebber shunyadragon's Avatar
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    Source: https://earthsky.org/space/thiophenes-organic-molecules-curiosity-rover-mars-life



    What’s cool about Curiosity’s discovery of organic molecules on Mars

    Posted by Paul Scott Anderson in SPACE | March 19, 2020

    The Curiosity rover has found organic molecules called thiophenes, which, on Earth, are associated with biological systems. Are they evidence for once-living microbes on Mars?

    The search for evidence of life on Mars, past or present, just took an interesting new twist. Researchers studying the data sent back by NASA’s Curiosity rover have found evidence for organic molecules called thiophenes, which, on Earth at least, are primarily a result of biological processes. The researchers are not claiming proof of life, but the discovery is certainly intriguing. The finding is being called “consistent with the presence of early life on Mars.”

    The findings were announced by researchers from Washington State University, and the peer-reviewed paper was published in the journal Astrobiology on February 24, 2020.

    On Earth, thiophenes are often found in coal, crude oil, kerogen and even a species of mushrooms called white truffles. They can also be found in stromatolites and microfossils. On Mars, they were found by Curiosity, along with other organics, in an ancient mudstone formation called the Murray Formation.

    The new paper explores some of the ways that thiophenes could be created on Mars, either biologically or abiotically (without life). As astrobiologist Dirk Schulze-Makuch, one of the two authors, explained in a statement:

    We identified several biological pathways for thiophenes that seem more likely than chemical ones, but we still need proof. If you find thiophenes on Earth, then you would think they are biological, but on Mars, of course, the bar to prove that has to be quite a bit higher.

    Thiophenes are essential to biology, containing four carbon atoms and one sulphur atom in a ring. They can, however, occur without any connection to life. On Mars, this could be from meteor impacts or perhaps thermochemical sulphate reduction (TSR), where a set of compounds is heated to 248 degrees Fahrenheit (120 degrees Celsius) or more. This could conceivably have happened during volcanic activity on early Mars.

    There are several ways that thiophenes can be formed biologically, however, which is what makes them of such interest to scientists looking for evidence of Martian life. Bacteria can create a sulphate reduction process – biological sulphate reduction (BSR) – that results in thiophenes. The thiophenes themselves can also be broken down by bacteria in several ways.

    One interesting aspect of the Martian thiophenes is that the geological processes that can create them require the sulphur to be nucleophilic, where sulphur atoms donate electrons to form a bond with their reaction partner. But most of the sulphur known to exist on Mars is non-nucleophilic. TSR could reduce them to nucleophilic sulphides, but so could BSR.

    One problem is that while Curiosity can detect molecules such as thiophenes, it is limited in how much detailed analysis it can do. The onboard lab it uses – the Sample Analysis at Mars (SAM) instrument – primarily breaks down large molecules into smaller pieces using heat, although some additional testing can be done using wet chemistry.

    So how can scientists tell if these thiophenes are biological or non-biological in origin?

    It isn’t easy with the tools that Curiosity has, so an answer will probably have to wait for a follow-up mission such as NASA’s Perseverance rover, set to launch this July, or Europe’s Rosalind Franklin rover, also scheduled to launch in July or August 2020.

    © Copyright Original Source

    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

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