Announcement

Collapse

Natural Science 301 Guidelines

This is an open forum area for all members for discussions on all issues of science and origins. This area will and does get volatile at times, but we ask that it be kept to a dull roar, and moderators will intervene to keep the peace if necessary. This means obvious trolling and flaming that becomes a problem will be dealt with, and you might find yourself in the doghouse.

As usual, Tweb rules apply. If you haven't read them now would be a good time.

Forum Rules: Here
See more
See less

Advances in the science of abiogenesis

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • shunyadragon
    replied
    Originally posted by Teallaura View Post
    Actually, introducing the attempt is the biggest problem of all - intellect is not a random process.
    Science does not consider 'intellect a random process. Puzzling remark needs claification.

    On that last point, true, it's not the same thing - but it's also not the same thing as random chance. It's a lot closer to the former than the latter - which is why the first article better supports ID rather than RC. I already conceded it can be used so don't yell but to prove RC, you've (general) got to get a model that doesn't involve intellect - and yeah, it's an incredibly high bar. Higher still when you look at the probabilities, but intellect invalidates random chance if it's present in the final model.
    The model that does not involve 'intellect' involves the 'Laws of Nature and natural processes' that falsified based on objective verifiable evidence.

    . . .the discoveries of new evidence and research supports the natural origins and evolution of life.

    Leave a comment:


  • shunyadragon
    replied
    Originally posted by Teallaura View Post
    Yeah... that doesn't read any differently this way.

    That is the reality as science researches the different possible ways abiogenesis took place. There is nothing in the research article that describes retro-engineering that would indicate it refers to Intelligent Dsign.

    Leave a comment:


  • Teallaura
    replied
    Originally posted by Roy View Post
    There's a major problem in practical abiogenesis research experiments in that people are effectively trying to duplicate what could happen in the world's oceans in millions of years, and they've got a bathtub and a month.

    So if they optimise environmental conditions and molecular concentrations and ratios in order to favour the reactions they're studying, that's understandable because there's literally no way on earth for them to duplicate the actual conditions. As long as they make it clear in their publications what they did and what the consequences are for how relevant their research is to actual possible history, it's not an issue.

    Oh, and while they may be intelligently designing their experiments to maximise success/usefulness, that's not the same as Intelligent Design.
    Actually, introducing the attempt is the biggest problem of all - intellect is not a random process.

    But I was merely observing the obvious - I still don't think they replicated the original results (my actual question) and in the first read, this didn't seem nearly as impressive to me as it is to Shuny. I wasn't intending to debate the thing - I'm still trying to digest it.

    On that last point, true, it's not the same thing - but it's also not the same thing as random chance. It's a lot closer to the former than the latter - which is why the first article better supports ID rather than RC. I already conceded it can be used so don't yell but to prove RC, you've (general) got to get a model that doesn't involve intellect - and yeah, it's an incredibly high bar. Higher still when you look at the probabilities, but intellect invalidates random chance if it's present in the final model.

    Leave a comment:


  • Teallaura
    replied
    Originally posted by shunyadragon View Post
    Again . . .

    here are two roughly methods: one. 'retro engineering,' they are experimenting on what reactions can be engineered to produce a given result, and when natural environments and conditions are created to determine what results can be achieved naturally. The present research deals more with the specific steps and problems in the abiogenesis process.
    Yeah... that doesn't read any differently this way.

    Leave a comment:


  • Roy
    replied
    Originally posted by Teallaura View Post
    The first is basically retro engineering - that can't answer abiogenesis except via Intelligent Design - so I presume they are using it as a stepping stone. Figure out the processes, then worry about whether or not nature can do them.
    There's a major problem in practical abiogenesis research experiments in that people are effectively trying to duplicate what could happen in the world's oceans in millions of years, and they've got a bathtub and a month.

    So if they optimise environmental conditions and molecular concentrations and ratios in order to favour the reactions they're studying, that's understandable because there's literally no way on earth for them to duplicate the actual conditions. As long as they make it clear in their publications what they did and what the consequences are for how relevant their research is to actual possible history, it's not an issue.

    Oh, and while they may be intelligently designing their experiments to maximise success/usefulness, that's not the same as Intelligent Design.

    Leave a comment:


  • shunyadragon
    replied
    Originally posted by Teallaura View Post
    The first is basically retro engineering - that can't answer abiogenesis except via Intelligent Design - so I presume they are using it as a stepping stone. Figure out the processes, then worry about whether or not nature can do them.

    The second has massive problems and doesn't seem related to the papers you cited in this thread so I'll just leave it be.


    Chemistry - I'm reading CHEMISTRY!!!


    Get back to you later...
    Again . . .

    here are two roughly methods: one. 'retro engineering,' they are experimenting on what reactions can be engineered to produce a given result, and when natural environments and conditions are created to determine what results can be achieved naturally. The present research deals more with the specific steps and problems in the abiogenesis process.

    Leave a comment:


  • Teallaura
    replied
    Originally posted by shunyadragon View Post
    This has nothing to do what can and cannot do. There are two roughly methods: one they are experimenting on what reactions can be engineered to produce a given result, and when natural environments and conditions are created to determine what results can be achieved naturally. The present research deals more with the specific steps and problems in the abiogenesis process.
    The first is basically retro engineering - that can't answer abiogenesis except via Intelligent Design - so I presume they are using it as a stepping stone. Figure out the processes, then worry about whether or not nature can do them.

    The second has massive problems and doesn't seem related to the papers you cited in this thread so I'll just leave it be.


    Please do . . .
    Chemistry - I'm reading CHEMISTRY!!!


    Get back to you later...

    Leave a comment:


  • shunyadragon
    replied
    Originally posted by Teallaura View Post
    Which doesn't help the case for undirected evolution at all - but does support Intelligent Design.


    So, basically, no, they can't replicate the result of creating self-replicating RNA and, if I'm reading this correctly, actually are showing that the problem is even more difficult than they thought originally.
    This has nothing to do what can and cannot do. There are two roughly methods: one they are experimenting on what reactions can be engineered to produce a given result, and when natural environments and conditions are created to determine what results can be achieved naturally. The present research deals more with the specific steps and problems in the abiogenesis process.

    Let me reread it later to make sure I get it.
    Please do . . .

    Leave a comment:


  • Teallaura
    replied
    Originally posted by shunyadragon View Post
    Directed engineering is not Intelligent Design. It just means they were able to do it in the lab through directed engineering,
    Which doesn't help the case for undirected evolution at all - but does support Intelligent Design.


    Good question.

    This is interesting more recent related research:

    Source: https://elifesciences.org/articles/35255



    Ribozyme-catalysed RNA synthesis using triplet building blocks

    Abstract
    RNA-catalyzed RNA replication is widely believed to have supported a primordial biology. However, RNA catalysis is dependent upon RNA folding, and this yields structures that can block replication of such RNAs. To address this apparent paradox, we have re-examined the building blocks used for RNA replication. We report RNA-catalysed RNA synthesis on structured templates when using trinucleotide triphosphates (triplets) as substrates, catalysed by a general and accurate triplet polymerase ribozyme that emerged from in vitro evolution as a mutualistic RNA heterodimer. The triplets cooperatively invaded and unraveled even highly stable RNA secondary structures, and support non-canonical primer-free and bidirectional modes of RNA synthesis and replication. Triplet substrates thus resolve a central incongruity of RNA replication, and here allow the ribozyme to synthesise its own catalytic subunit ‘+’ and ‘–’ strands in segments and assemble them into a new active ribozyme.

    https://doi.org/10.7554/eLife.35255.001

    Introduction

    The premise that some RNA sequences can catalyse and template their own replication - reciprocally synthesizing their own ‘+’ and ‘–’ strands - underpins current thinking about early genetic systems (Crick, 1968; Orgel, 1968; Szostak et al., 2001). Any ancient ribozyme with such RNA replicase capability seems to be lost, but efforts are ongoing to recreate RNA self-replication in the laboratory (Martin et al., 2015) as a critical test of the ‘RNA world’ hypothesis (Gilbert, 1986). Early on, derivatives of naturally occurring self-splicing introns (Doudna et al., 1991; Green and Szostak, 1992; Hayden and Lehman, 2006) as well as later in vitro evolved ligase ribozymes (Lincoln and Joyce, 2009; Sczepanski and Joyce, 2014) were shown to be able to assemble one of their own strands from cognate constituent RNA segments. However, a critical drawback of such systems is their need for specific preformed building blocks of at least eight nucleotides (nt) average length, limiting their potential for open-ended evolution, and precluding their replication from pools of random-sequence oligonucleotide substrates (Green and Szostak, 1992; Doudna et al., 1993).

    In a contrasting approach, RNA polymerase ribozymes (RPRs) have been developed that can use general monomer building blocks (ribonucleoside 5’ triphosphates (NTPs)) in RNA-templated RNA synthesis (Johnston et al., 2001; Zaher and Unrau, 2007; Wochner et al., 2011; Attwater et al., 2013b; Horning and Joyce, 2016), akin to the activity of modern proteinaceous polymerases. However, even the most highly-evolved RPRs (Horning and Joyce, 2016) are substantially impeded by template secondary structures. Such structures are ubiquitous in larger, functional RNAs (including the RPRs themselves) and generally indispensable for function. The strong inhibitory role of this central feature of RNA leads to an antagonism between the degree to which an RNA sequence is able to fold into a defined three-dimensional structure to encode function (such as catalysis) and the ease with which it can be replicated (Boza et al., 2014). This ostensible ‘structure vs. replication’ paradox would have placed stringent probability constraints on the emergence of an RNA replicase and generally impeded the ability of RNA to function as an early genetic polymer.

    We wondered whether this paradox might be avoided through a re-consideration of plausible building blocks for early RNA replication. Models of non-enzymatic polymerisation of all four activated ribonucleotides – the presumed source of the first RNA sequences – yield pools of di-, tri- and tetranucleotide etc. length oligonucleotides (in decreasing abundance) dominating the population alongside longer products (Monnard et al., 2003). Here, we have examined whether substrates of such lengths can support RNA-catalyzed RNA replication, by developing a ribozyme capable of iterative templated ligation of 5’-triphosphorylated RNA trinucleotides (henceforth called triplets). This heterodimeric triplet polymerase ribozyme demonstrated a striking capacity to copy a wide range of RNA sequences, including highly structured, previously intractable RNA templates, as well as its own catalytic domain and encoding template in segments. Its characterization revealed emergent properties of triplet-based RNA synthesis, including cooperative invasion and unraveling of stable RNA structures by triplet substrates, bi-directional (both 5’−3’ and 3’−5’) and primer-free (triplet-initiated) RNA synthesis, and fidelity augmented by systemic properties of the random triplet pools.

    Results

    In vitro evolution of triplet polymerase activity

    We set out to explore the potential of short RNA oligonucleotides as substrates for RNA-catalyzed RNA replication. To do this, we required a ribozyme capable of general, iterative RNA-templated oligonucleotide ligation. Previously-described RNA polymerase ribozymes such as the ‘Z’ RPR (Wochner et al., 2011) can use NTPs to iteratively extend a primer hybridized to an RNA template, but do not accommodate oligonucleotides bound downstream of the primer or accept them as substrates. However, we detected a weak templated ligation activity in a truncated version of the Z RPR comprising its catalytic core domain (Zcore) (Figure 1a), which supported incorporation of oligonucleotide substrates as short as three nt (Figure 1—figure supplement 1) when incubated in the eutectic phase of water ice (Attwater et al., 2010; Mutschler et al., 2015).

    © Copyright Original Source

    So, basically, no, they can't replicate the result of creating self-replicating RNA and, if I'm reading this correctly, actually are showing that the problem is even more difficult than they thought originally.

    Let me reread it later to make sure I get it.

    Leave a comment:


  • shunyadragon
    replied
    Originally posted by Teallaura View Post
    *emphasis mine

    So, are they trying to advance Intelligent Design or just proving that retro-engineering is a thing?
    Directed engineering is not Intelligent Design. It just means they were able to do it in the lab through directed engineering,

    But more importantly, has it been replicated? These are fairly old papers and didn't seem to create much of a stir at the time - what has been done since?
    Good question.

    This is interesting more recent related research:

    Source: https://elifesciences.org/articles/35255



    Ribozyme-catalysed RNA synthesis using triplet building blocks

    Abstract
    RNA-catalyzed RNA replication is widely believed to have supported a primordial biology. However, RNA catalysis is dependent upon RNA folding, and this yields structures that can block replication of such RNAs. To address this apparent paradox, we have re-examined the building blocks used for RNA replication. We report RNA-catalysed RNA synthesis on structured templates when using trinucleotide triphosphates (triplets) as substrates, catalysed by a general and accurate triplet polymerase ribozyme that emerged from in vitro evolution as a mutualistic RNA heterodimer. The triplets cooperatively invaded and unraveled even highly stable RNA secondary structures, and support non-canonical primer-free and bidirectional modes of RNA synthesis and replication. Triplet substrates thus resolve a central incongruity of RNA replication, and here allow the ribozyme to synthesise its own catalytic subunit ‘+’ and ‘–’ strands in segments and assemble them into a new active ribozyme.

    https://doi.org/10.7554/eLife.35255.001

    Introduction

    The premise that some RNA sequences can catalyse and template their own replication - reciprocally synthesizing their own ‘+’ and ‘–’ strands - underpins current thinking about early genetic systems (Crick, 1968; Orgel, 1968; Szostak et al., 2001). Any ancient ribozyme with such RNA replicase capability seems to be lost, but efforts are ongoing to recreate RNA self-replication in the laboratory (Martin et al., 2015) as a critical test of the ‘RNA world’ hypothesis (Gilbert, 1986). Early on, derivatives of naturally occurring self-splicing introns (Doudna et al., 1991; Green and Szostak, 1992; Hayden and Lehman, 2006) as well as later in vitro evolved ligase ribozymes (Lincoln and Joyce, 2009; Sczepanski and Joyce, 2014) were shown to be able to assemble one of their own strands from cognate constituent RNA segments. However, a critical drawback of such systems is their need for specific preformed building blocks of at least eight nucleotides (nt) average length, limiting their potential for open-ended evolution, and precluding their replication from pools of random-sequence oligonucleotide substrates (Green and Szostak, 1992; Doudna et al., 1993).

    In a contrasting approach, RNA polymerase ribozymes (RPRs) have been developed that can use general monomer building blocks (ribonucleoside 5’ triphosphates (NTPs)) in RNA-templated RNA synthesis (Johnston et al., 2001; Zaher and Unrau, 2007; Wochner et al., 2011; Attwater et al., 2013b; Horning and Joyce, 2016), akin to the activity of modern proteinaceous polymerases. However, even the most highly-evolved RPRs (Horning and Joyce, 2016) are substantially impeded by template secondary structures. Such structures are ubiquitous in larger, functional RNAs (including the RPRs themselves) and generally indispensable for function. The strong inhibitory role of this central feature of RNA leads to an antagonism between the degree to which an RNA sequence is able to fold into a defined three-dimensional structure to encode function (such as catalysis) and the ease with which it can be replicated (Boza et al., 2014). This ostensible ‘structure vs. replication’ paradox would have placed stringent probability constraints on the emergence of an RNA replicase and generally impeded the ability of RNA to function as an early genetic polymer.

    We wondered whether this paradox might be avoided through a re-consideration of plausible building blocks for early RNA replication. Models of non-enzymatic polymerisation of all four activated ribonucleotides – the presumed source of the first RNA sequences – yield pools of di-, tri- and tetranucleotide etc. length oligonucleotides (in decreasing abundance) dominating the population alongside longer products (Monnard et al., 2003). Here, we have examined whether substrates of such lengths can support RNA-catalyzed RNA replication, by developing a ribozyme capable of iterative templated ligation of 5’-triphosphorylated RNA trinucleotides (henceforth called triplets). This heterodimeric triplet polymerase ribozyme demonstrated a striking capacity to copy a wide range of RNA sequences, including highly structured, previously intractable RNA templates, as well as its own catalytic domain and encoding template in segments. Its characterization revealed emergent properties of triplet-based RNA synthesis, including cooperative invasion and unraveling of stable RNA structures by triplet substrates, bi-directional (both 5’−3’ and 3’−5’) and primer-free (triplet-initiated) RNA synthesis, and fidelity augmented by systemic properties of the random triplet pools.

    Results

    In vitro evolution of triplet polymerase activity

    We set out to explore the potential of short RNA oligonucleotides as substrates for RNA-catalyzed RNA replication. To do this, we required a ribozyme capable of general, iterative RNA-templated oligonucleotide ligation. Previously-described RNA polymerase ribozymes such as the ‘Z’ RPR (Wochner et al., 2011) can use NTPs to iteratively extend a primer hybridized to an RNA template, but do not accommodate oligonucleotides bound downstream of the primer or accept them as substrates. However, we detected a weak templated ligation activity in a truncated version of the Z RPR comprising its catalytic core domain (Zcore) (Figure 1a), which supported incorporation of oligonucleotide substrates as short as three nt (Figure 1—figure supplement 1) when incubated in the eutectic phase of water ice (Attwater et al., 2010; Mutschler et al., 2015).

    © Copyright Original Source

    Leave a comment:


  • Teallaura
    replied
    Originally posted by shunyadragon View Post
    Self Replicating RNA emerges in the lab through directed evolution.

    Source: https://www.cell.com/cell-chemical-biology/fulltext/S1074-5521(13)00426-2



    An RNA enzyme has been developed that catalyzes the joining of oligonucleotide substrates to form additional copies of itself, undergoing self-replication with exponential growth. The enzyme also can cross-replicate with a partner enzyme, resulting in their mutual exponential growth and enabling self-sustained Darwinian evolution. The opportunity for inventive evolution within this synthetic genetic system depends on the diversity of the evolving population, which is limited by the catalytic efficiency of the enzyme. Directed evolution was used to improve the efficiency of the enzyme and increase its exponential growth rate to 0.14 min−1, corresponding to a doubling time of 5 min. This is close to the limit of 0.21 min−1imposed by the rate of product release, but sufficient to enable more than 80 logs of growth per day.

    To enable the propagation of genetic information, the self-replicating RNA ligase has been converted to a cross-replication format whereby two RNA enzymes catalyze each other’s synthesis from a total of four component substrates ( Kim and Joyce, 2004). Information is transmitted between the parent and progeny enzymes through two regions of Watson-Crick pairing, each of which may contain many possible sequences. Recombination can occur between these two regions, resulting in novel variants that compete for utilization of the oligonucleotide substrates. Those variants that have faster exponential growth rates enjoy a selective advantage, resulting in the self-sustained Darwinian evolution of the fittest replicators ( Lincoln and Joyce, 2009).

    © Copyright Original Source

    *emphasis mine

    So, are they trying to advance Intelligent Design or just proving that retro-engineering is a thing?

    But more importantly, has it been replicated? These are fairly old papers and didn't seem to create much of a stir at the time - what has been done since?

    Leave a comment:


  • shunyadragon
    replied
    Source: https://www.sciencenews.org/article/droplets-acid-molecules-may-have-helped-kick-start-life-earth?utm_source=email&utm_medium=email&utm_campaign=latest-newsletter-v2&utm_source=Latest_Headlines&utm_medium=email&utm_campaign=Latest_Headlines



    Droplets of these simple molecules may have helped kick-start life on Earth

    Small blobs that break apart and reform can host protein and RNA

    A new study shows that a simple class of molecules called alpha hydroxy acids forms microdroplets when dried and rewetted, as could have taken place at the edges of water sources. These cell-sized compartments can trap RNA, and can merge and break apart — behavior that could have encouraged inanimate molecules in the primordial soup to give rise to life, researchers report July 22 in the Proceedings of the National Academy of Sciences.

    Besides giving clues to how life may have gotten started on the planet, the work might have additional applications in both medicine and the search for extraterrestrial life.

    Present-day biology relies on cells to concentrate nutrients and protect genetic information, so many scientists think that compartments could have been important for life to begin. But no one knows whether the first microenclosures on Earth were related to modern cells.

    “The early Earth was certainly a messy place chemically,” with nonbiological molecules such as alpha hydroxy acids potentially having roles in the emergence of life alongside biomolecules like RNA and their precursors, says biochemist Tony Jia of Tokyo Institute of Technology’s Earth-Life Science Institute.

    Jia’s team focused on mixtures of alpha hydroxy acids, some of which are common in skin-care cosmetics. Though not as prominent as their chemical relatives amino acids, alpha hydroxy acids are plausible players in origin-of-life happenings because they frequently show up in meteorites as well as in experiments mimicking early Earth chemistry.

    In 2018, a team led by geochemists Kuhan Chandru of the Earth-Life Science Institute and the National University of Malaysia at Bangi and H. James Cleaves, also of the Earth-Life Science Institute, demonstrated that, just though drying, alpha hydroxy acids form repeating chains of molecules called polymers. In the new study, the pair along with Jia and their colleagues found that rewetting the polymers led to the formation of microdroplets about the same diameter as modern red blood cells or cheek cells.

    Prior studies have shown that simple molecules can form droplets (SN: 4/15/17, p. 11). The new work goes further in showing “that possibly prebiotically relevant molecules can form droplets,” says artificial cell expert Dora Tang of the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany, who wasn’t involved with the work.

    In the lab, the team demonstrated that the droplets could trap and host molecules essential to life as we know it, such as RNA. The researchers also observed that a protein retained its function within the droplets and that fatty acids could assemble around the droplets.

    Still, those findings don’t mean the microdroplets were Earth’s first cells or ancestors of them, Chandru cautions. Instead, he suggests that the droplets could have helped reactions along in emerging biochemical systems in the lead-up to the origin of life.

    Though the team’s focus is origin-of-life studies, Jia points out that these microdroplets could potentially be engineered to deliver medications. The researchers note in their study that they may apply for a patent related to the work within the next year but have not specified an application.

    The new research may also hold an important lesson for the search for extraterrestrial life (SN: 4/30/16, p. 28). “We need to not only focus on detection of modern biomolecules and their precursors, but also other relevant nonbiomolecules” that, like alpha hydroxy acids, might have played supporting roles in the emergence of life, on Earth or elsewhere, Jia says.

    Citations
    T. Jia et al. Membraneless polyester microdroplets as primordial compartments at the origins of life. Proceedings of the National Academy of Sciences. Published online July 22, 2019. doi:10.1073/pnas.1902336116.

    K. Chandru et al. Simple prebiotic synthesis of high diversity dynamic combinatorial polyester libraries. Communications Chemistry. Vol. 1, May 2018. doi:10.1038/s42004-018-0031-1.

    Further Reading
    E. Conover. Life on Earth may have begun as dividing droplets. Science News. Vol. 191, April 15, 2017, p. 11.

    T.H. Saey. Will we know extraterrestrial life when we see it? Science News. Vol. 189, April 30, 2016, p. 28.

    © Copyright Original Source

    Last edited by shunyadragon; 07-23-2019, 06:59 PM.

    Leave a comment:


  • shunyadragon
    replied
    Self Replicating RNA emerges in the lab through directed evolution.

    Source: https://www.cell.com/cell-chemical-biology/fulltext/S1074-5521(13)00426-2



    An RNA enzyme has been developed that catalyzes the joining of oligonucleotide substrates to form additional copies of itself, undergoing self-replication with exponential growth. The enzyme also can cross-replicate with a partner enzyme, resulting in their mutual exponential growth and enabling self-sustained Darwinian evolution. The opportunity for inventive evolution within this synthetic genetic system depends on the diversity of the evolving population, which is limited by the catalytic efficiency of the enzyme. Directed evolution was used to improve the efficiency of the enzyme and increase its exponential growth rate to 0.14 min−1, corresponding to a doubling time of 5 min. This is close to the limit of 0.21 min−1imposed by the rate of product release, but sufficient to enable more than 80 logs of growth per day.

    To enable the propagation of genetic information, the self-replicating RNA ligase has been converted to a cross-replication format whereby two RNA enzymes catalyze each other’s synthesis from a total of four component substrates ( Kim and Joyce, 2004). Information is transmitted between the parent and progeny enzymes through two regions of Watson-Crick pairing, each of which may contain many possible sequences. Recombination can occur between these two regions, resulting in novel variants that compete for utilization of the oligonucleotide substrates. Those variants that have faster exponential growth rates enjoy a selective advantage, resulting in the self-sustained Darwinian evolution of the fittest replicators ( Lincoln and Joyce, 2009).

    © Copyright Original Source

    Leave a comment:


  • shunyadragon
    replied
    Source: https://www.sciencedaily.com/releases/2018/11/181120125822.htm


    Amino acid chains spontaneously build up in typical early earth conditions recreated in labs.
    Could yesterday's Earth contain clues for making tomorrow's medicines?
    Izabela Sibilska, Yu Feng, Lingjun Li, John Yin. Trimetaphosphate Activates Prebiotic Peptide Synthesis across a Wide Range of Temperature and pH. Origins of Life and Evolution of Biospheres, 2018; 48

    Research abstract:-
    The biochemical activation of amino acids by adenosine triphosphate (ATP) drives the synthesis of proteins that are essential for all life. On the early Earth, before the emergence of cellular life, the chemical condensation of amino acids to form prebiotic peptides or proteins may have been activated by inorganic polyphosphates, such as tri metaphosphate (TP). Plausible volcanic and other potential sources of TP are known, and TP readily activates amino acids for peptide synthesis. But de novo peptide synthesis also depends on pH, temperature, and processes of solvent drying, which together define a varied range of potential activating conditions. Although we cannot replay the tape of life on Earth, we can examine how activator, temperature, acidity and other conditions may have collectively shaped its prebiotic evolution. Here, reactions of two simple amino acids, glycine and alanine, were tested, with or without TP, over a wide range of temperature (0-100 °C) and acidity (pH 1-12), while open to the atmosphere. After 24 h, products were analyzed by HPLC and mass spectrometry. In the absence of TP, glycine and alanine readily formed peptides under harsh near-boiling temperatures, extremes of pH, and within dry solid residues. In the presence of TP, however, peptides arose over a much wider range of conditions, including ambient temperature, neutral pH, and in water. These results show how polyphosphates such as TP may have enabled the transition of peptide synthesis from harsh to mild early Earth environments, setting the stage for the emergence of more complex prebiotic chemistries.

    © Copyright Original Source

    Leave a comment:


  • shunyadragon
    replied
    Originally posted by lee_merrill View Post
    They formed ribonucleotides, that would not be RNA.

    Blessings,
    Lee
    correct . . .

    "Researchers synthesized the basic ingredients of RNA, a molecule from which the simplest self-replicating structures are made. Until now, they couldn't explain how these ingredients might have formed."

    more to follow . . .

    Leave a comment:

Related Threads

Collapse

Topics Statistics Last Post
Started by Hypatia_Alexandria, 03-18-2024, 12:15 PM
48 responses
135 views
0 likes
Last Post Sparko
by Sparko
 
Started by Sparko, 03-07-2024, 08:52 AM
16 responses
74 views
0 likes
Last Post shunyadragon  
Started by rogue06, 02-28-2024, 11:06 AM
6 responses
47 views
0 likes
Last Post shunyadragon  
Working...
X