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Biologists Replicate Key Evolutionary Step

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Origin of life: Simulating how Earth kick-started metabolism

 


In the new study, the researchers have demonstrated a proof of concept for their fuel cell model of the emergence of cell metabolism on Earth.

In the Energy Leeds Renewable Lab at the University of Leeds and NASA's Jet Propulsion Laboratory, the team replaced traditional platinum catalysts in fuel cells and electrical experiments with those composed of geological minerals.
 
Dr Laura Barge from the NASA Astrobiology Institute 'Icy Worlds' team at JPL in California, US, and lead author of the paper, said: "Certain minerals could have driven geological redox reactions, later leading to a biological metabolism. We're particularly interested in electrically conductive minerals containing iron and nickel that would have been common on the early Earth."
 
Iron and nickel are much less reactive than platinum. However, a small but significant power output successfully demonstrated that these metals could still generate electricity in the fuel cell -- and hence also act as catalysts for redox reactions within hydrothermal vents in the early Earth.
 
For now, the chemistry of how geological reactions driven by inanimate rocks and minerals evolved into biological metabolisms is still a black box. But with a laboratory-based model for simulating these processes, scientists have taken an important step forward to understanding the origin of life on this planet and whether a similar process could occur on other worlds.

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Study tests theory that life originated at deep sea vents (and fails to pass the this specific test.)

 

The question Reeves and his colleagues set out to test was whether methanethiol -- a critical precursor of life -- could form at modern day vent sites by purely chemical means without the involvement of life. Could methanethiol be the bridge between a chemical, non-living world and the first microbial life on the planet?

 

Critically, the researchers found an abundance of methanethiol being formed in low temperature fluids (below about 200°C), where hot black smoker fluid mixes with colder sea water beneath the seafloor. The presence of other telltale markers in these fluids, such as ammonia -- a byproduct of biomass breakdown -- strongly suggests these fluids are 'cooking' existing microbial organic matter. The breakdown of existing subseafloor life when conditions get too hot may therefore be responsible for producing large amounts of methanethiol.

 

"What we essentially found in our survey is that we don't think methanethiol is forming by purely chemical means without the involvement of life. This might be disappointing news for anyone assuming an easy start for hydrothermal proto-metabolism," says Reeves. "However, our finding that methanethiol may be readily forming as a breakdown product of microbial life provides further indication that life is present and widespread below the seafloor and is very exciting."

Edited by dream_weaver

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New study outlines 'water world' theory of life's origins

 

According to the findings, which also can be thought of as the "water world" theory, life may have begun inside warm, gentle springs on the sea floor, at a time long ago when Earth's oceans churned across the entire planet. This idea of hydrothermal vents as possible places for life's origins was first proposed in 1980 by other researchers, who found them on the sea floor near Cabo San Lucas, Mexico. Called "black smokers," those vents bubble with scalding hot, acidic fluids. In contrast, the vents in the new study -- first hypothesized by scientist Michael Russell of JPL in 1989 -- are gentler, cooler and percolate with alkaline fluids. One such towering complex of these alkaline vents was found serendipitously in the North Atlantic Ocean in 2000, and dubbed the Lost City.

 

 

 

The water world theory from Russell and his team says that the warm, alkaline hydrothermal vents maintained an unbalanced state with respect to the surrounding ancient, acidic ocean -- one that could have provided so-called free energy to drive the emergence of life. In fact, the vents could have created two chemical imbalances. The first was a proton gradient, where protons -- which are hydrogen ions -- were concentrated more on the outside of the vent's chimneys, also called mineral membranes. The proton gradient could have been tapped for energy -- something our own bodies do all the time in cellular structures called mitochondria.

 

The second imbalance could have involved an electrical gradient between the hydrothermal fluids and the ocean. Billions of years ago, when Earth was young, its oceans were rich with carbon dioxide. When the carbon dioxide from the ocean and fuels from the vent -- hydrogen and methane -- met across the chimney wall, electrons may have been transferred. These reactions could have produced more complex carbon-containing, or organic compounds -- essential ingredients of life as we know it. Like proton gradients, electron transfer processes occur regularly in mitochondria.

 

 This appears to disregard the methanethiol referenced in the previous post. 

 

As is the case with all advanced life forms, enzymes are the key to making chemical reactions happen. In our ancient oceans, minerals may have acted like enzymes, interacting with chemicals swimming around and driving reactions. In the water world theory, two different types of mineral "engines" might have lined the walls of the chimney structures.

 

"These mineral engines may be compared to what's in modern cars," said Russell.

 

"They make life 'go' like the car engines by consuming fuel and expelling exhaust. DNA and RNA, on the other hand, are more like the car's computers because they guide processes rather than make them happen."

 

One of the tiny engines is thought to have used a mineral known as green rust, allowing it to take advantage of the proton gradient to produce a phosphate-containing molecule that stores energy. The other engine is thought to have depended on a rare metal called molybdenum. This metal also is at work in our bodies, in a variety of enzymes. It assists with the transfer of two electrons at a time rather than the usual one, which is useful in driving certain key chemical reactions.

 

"We call molybdenum the Douglas Adams element," said Russell, explaining that the atomic number of molybdenum is 42, which also happens to be the answer to the "ultimate question of life, the universe and everything" in Adams' popular book, "The Hitchhiker's Guide to the Galaxy." Russell joked, "Forty-two may in fact be one answer to the ultimate question of life!"

 

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At the origin of cell division: The features of living matter emerge from inanimate matter in simulation

 

Giomi and DeSimone's artificial cells are in fact computer models that mimic some of the physical properties of the materials making up the inner content and outer membrane of cells.

 

The force exerted by the filaments is the variable that competes with another force, the surface tension that keeps the membrane surrounding the droplet from collapsing. The generates a flow in the fluid surrounding the droplet, which in turn is propelled by such self-generated flow. When the flow becomes very strong, the droplet deforms to the point of dividing. "When the force of the flow prevails over the force that keeps the membrane together we have cellular division," explains DeSimone, director of the SISSA mathLab, SISSA's mathematical modelling and scientific computing laboratory.

 

 

 

"Acquiring motility and the ability to divide is a fundamental step for life and, according to our simulations, the laws governing these phenomena could be very simple. Observations like ours can prepare the way for the creation of functioning artificial cells, and not only," comments Giomi. "Our work is also useful for understanding the transition from non-living to living matter on our planet. The development of the early forms of life, in other words."

 

Chemists and biologists who study the origin of life don't have access to cells that are sufficiently simple to be observed directly.

 

Keeping in mind that this computer program admittedly mimics some of the physical properties. Extrapolating this; any computer program can only mimic discovered physical properties.

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Scientists achieve first direct observations of excitons in motion

 

Summary:

A quasiparticle called an exciton -- responsible for the transfer of energy within devices such as solar cells, LEDs, and semiconductor circuits -- has been understood theoretically for decades. But exciton movement within materials has never been directly observed. Now scientists have achieved that feat, imaging excitons' motions directly. This could enable research leading to significant advances in electronics, they say, as well as a better understanding of natural energy-transfer processes, such as photosynthesis.

 

An exciton, which travels through matter as though it were a particle, pairs an electron, which carries a negative charge, with a place where an electron has been removed, known as a hole. Overall, it has a neutral charge, but it can carry energy. For example, in a solar cell, an incoming photon may strike an electron, kicking it to a higher energy level. That higher energy is propagated through the material as an exciton: The particles themselves don't move, but the boosted energy gets passed along from one to another.

 

Exciton diffusion is also a basic mechanism underlying photosynthesis: Plants absorb energy from photons, and this energy is transferred by excitons to areas where it can be stored in chemical form for later use in supporting the plant's metabolism. The new method might provide an additional tool for studying some aspects of this process, the team says.

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Reconstructed ancient ocean reveals secrets about the origin of life

 

A reconstruction of Earth's earliest ocean in the laboratory revealed the spontaneous occurrence of the chemical reactions used by modern cells to synthesize many of the crucial organic molecules of metabolism. Previously, it was assumed that these reactions were carried out in modern cells by metabolic enzymes, highly complex molecular machines that came into existence during the evolution of modern organisms.

 

"Our results demonstrate that the conditions and molecules found in the Earth's ancient oceans assisted and accelerated the interconversion of metabolites that in modern organisms make up glycolysis and the pentose-phosphate pathways, two of the essential and most centrally placed reaction cascades of metabolism," says Dr. Markus Ralser, Group Leader at the Department of Biochemistry at the University of Cambridge and the National Institute for Medical Research. "In our reconstructed version of the ancient Archean ocean, these metabolic reactions were particularly sensitive to the presence of ferrous iron that helped catalyze many of the chemical reactions that we observed."

 

Some of the observed reactions could also take place in water but were accelerated by the presence of metals that served as catalysts. "In the presence of iron and other compounds found in the oceanic sediments, 29 metabolic-like chemical reactions were observed, including those that produce some of the essential chemicals of metabolism, for example precursors of the building blocks of proteins or RNA," says Ralser. "These results indicate that the basic architecture of the modern metabolic network could have originated from the chemical and physical constraints that existed on the prebiotic Earth."

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Origin of life: Stanley Miller's forgotten experiments, analyzed

 

Summary:

Stanley Miller, the chemist whose landmark experiment published in 1953 showed how some of the molecules of life could have formed on a young Earth, left behind boxes of experimental samples that he never analyzed. The first-ever analysis of some of Miller's old samples has revealed another way that important molecules could have formed on early Earth.

 

Excerpt:

The boxes of unanalyzed samples had been preserved and carefully marked, down to the page number where the experiment was described in Miller's laboratory notebooks. The researchers verified that the contents of the box of samples were from an electric discharge experiment conducted with cyanamide in 1958 when Miller was at the Department of Biochemistry at the College of Physicians and Surgeons, Columbia University.

 

An electric discharge experiment simulates early Earth conditions using relatively simple starting materials. The reaction is ignited by a spark, simulating lightning, which was likely very common on the early Earth.

 

The 1958 reaction samples were analyzed by Parker and his current mentor, Facundo M. Fernández, a professor in the School of Chemistry and Biochemistry at Georgia Tech. They conducted liquid chromatography- and mass spectrometry-based analyses and found that the reaction samples from 1958 contained peptides. Scientists from NASA's Johnson Space Center and Goddard Space Flight Center were also involved in the analysis.

 

The research team then set out to replicate the experiment. Parker designed a way to do the experiment using modern equipment and confirmed that the reaction created peptides.

Edited by dream_weaver

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New molecule found in space connotes life origins

 

Summary:

Hunting from a distance of 27,000 light years, astronomers have discovered an unusual carbon-based molecule contained within a giant gas cloud in interstellar space. The discovery suggests that the complex molecules needed for life may have their origins in interstellar space.

 

Excerpt;

Organic molecules usually found in these star-forming regions consist of a single "backbone" of carbon atoms arranged in a straight chain. But the carbon structure of isopropyl cyanide branches off, making it the first interstellar detection of such a molecule, says Rob Garrod, Cornell senior research associate at the Center for Radiophysics and Space Research.

 

This detection opens a new frontier in the complexity of molecules that can be formed in interstellar space and that might ultimately find their way to the surfaces of planets, says Garrod. The branched carbon structure of isopropyl cyanide is a common feature in molecules that are needed for life -- such as amino acids, which are the building blocks of proteins. This new discovery lends weight to the idea that biologically crucial molecules, like amino acids that are commonly found in meteorites, are produced early in the process of star formation -- even before planets such as Earth are formed.

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Molecules that came in handy for first life on Earth

 

Excerpts:

Some molecules are found in two chiral variants that, just like hands, are mirror images of one another. Nature, however, makes use of only one variant; for example, DNA is made of a right-handed helix and the most common sugar -- glucose -- is also right-handed. Why nature does this, and how it all started, remains an intriguing puzzle. After all, whenever chemists make the same molecules they obtain a mix of both variants.

An article by Kenso Soai in Nature in 1995 described the experimental realization for the first time, but this only worked after addition of a pinch of the left-handed or right-handed product to start with. The Radboud chemists however took it an important step further: they updated Frank's concept and discovered a spontaneous asymmetric synthesis method which takes place in the absence of left- or right-handed molecules. René Steendam: "The first left-handed amino acids could have been produced in this way, no matter whether this happened on earth or somewhere else in the universe."

"No one has done this before, no-one has achieved -- in a single, simple reaction, in a single beaker with no chirality present -- an end situation that is 100 % left-handed or 100 % right-handed" says Elias Vlieg, Professor of Solid State Chemistry.

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The origin of life: Labyrinths as crucibles of life

Source: Ludwig-Maximilians-Universität München

 

Summary:

Water-filled micropores in hot rock may have acted as the nurseries in which life on Earth began. A team has now shown that temperature gradients in pore systems promote the cyclical replication and emergence of nucleic acids.

 

Excerpts:

"The key requirement is that the heat source be localized on one side of the elongated pore, so that the water on that side is significantly warmer than that on the other," says Braun. Preformed biomolecules that are washed into the pore can then be trapped, and concentrated, by the action of the temperature gradient -- thus fulfilling a major prerequisite for the formation and replication of more complex molecular structures. The molecular trapping effect is a consequence of thermophoresis: Charged molecules in a temperature gradient preferentially move from the warmer to the cooler region, allowing longer polymers in particular to be securely trapped. This is an important factor in the evolution of nucleic acids such as RNA and DNA, simply because longer molecules can store more genetic information.

 

I do wish a different term than information would be selected. I get the gist of what is meant, but find it often used as an open invitation for equivocation.

 

Recreating rock pores in the laboratory

Braun and his colleagues have shown that this mechanism works in the laboratory: "We used tiny glass capillary tubes to construct an analog of the natural pores found in rock, heated the pore from one side and allowed water containing dissolved fragments of linear DNA of varying lengths to percolate through it. Under such conditions, the long strands are indeed trapped within the pore," Braun explains. "Pores that were exposed to heat are frequently found in igneous rock formations, and they were certainly common in rocks of volcanic origin on the early Earth. So this scenario is quite realistic. And the temperature effect is enhanced by the presence of metal inclusions within the rock, which conduct heat at rates 100 times higher than water."

 

Temperature gradients and replication

Not only are nucleic acids retained in the pore, they are also capable of replication under these conditions. In the hotter zone, double-stranded strands are separated into its component strands within minutes. The single strands can then be transported by convection -- cyclical flow along the pore perpendicular to the orientation of temperature gradient -- back to the colder region of the pore. Here they encounter the chemical precursors from which each DNA strand is built, which are fed into the pore by a continuous inflow. The preformed strands then act as templates for the polymerization of complementary strands. This cycle makes it possible not only to replicate the strands but also to elongate them by stitching fragments together. When the nucleic acids accumulate to levels beyond the storage capacity of the pore, newly replicated molecules can escape and colonize neighboring pore systems.

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Link found in how cells start process necessary for life

 

Date: February 11, 2015
Source: University of Colorado Denver
Summary:
Researchers have found an RNA structure-based signal that spans billions of years of evolutionary divergence between different types of cells, according to a new study. The finding could alter the basic understanding of how two distinct life forms -- bacteria and eukaryotes -- begin the process of protein synthesis.

 

Excerpts:

Jeffrey Kieft, PhD, professor of biochemistry and molecular genetics and corresponding author of the article in Nature, said scientists have long thought that the molecular signals that initiate protein synthesis in bacteria and eukaryotes are mutually exclusive. Scientists in Kieft's lab explored whether a structured RNA molecule from a virus that infects eukaryotic cells could function in bacteria. Surprisingly, they found that it could initiate protein syntheses, a process necessary for life.

 

Eukaryotes are organisms, such as plants, animals and fungi, whose cells contain a nucleus and are enclosed within membranes, while prokaryotes, such as bacteria, do not contain a nucleus.

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Discovery demystifies origin of life phenomenon

 

Summary:

Biomolecules, if large enough (several nanometers) and with an electrical charge, will seek their own type with which to form large assemblies. This is essentially 'self-recognition' of left-handed and right-handed molecule pairs.

 

Excerpt:

Liu explains that all life molecules are paired as left-handed and right-handed structures. In scientific terms, the phenomenon is called chirality. Nature's selection of only right-handed sugars and left-handed amino acids upon which to build life might be much simpler than we expected before.

 

Liu found that any molecules, if large enough (several nanometers) and with an electrical charge, will seek their own type with which to form large assemblies. This "self-recognition" of left-handed and right-handed molecule pairs is featured in the March 10, 2015 issue of Nature Communications.

 

"We show that homochirality, or the manner in which molecules select other like molecules to form larger assemblies, may not be as mysterious as we imagined," Liu says.

 

While an understanding of how homochirality occurred at the onset of life remains a mystery, this new finding emphasizes that Mother Nature's inner workings may not be as complex as we think.

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Chemists claim to have solved riddle of how life began on Earth

Excerpts:

A team of chemists working at the MRC Laboratory of Molecular Biology, at Cambridge in the UK believes they have solved the mystery of how it was possible for life to begin on Earth over four billion years ago. In their paper published in the journal Nature Chemistry, the team describes how they were able to map reactions that produced two and three-carbon sugars, amino acids, ribonucleotides and glycerol—the material necessary for metabolism and for creating the building blocks of proteins and ribonucleic acid molecules and also for allowing for the creation of lipids that form cell membranes.

 

 — they believe they have found a way to show that everything necessary for life to evolve could have done so from just hydrogen sulfide, hydrogen cyanide and ultraviolet light and that those building blocks could have all existed at the same time—in their paper, they report that using just those three basic ingredients they were able to produce more than 50 nucleic acids—precursors to DNA and RNA molecules.
 

I wonder how these products compare to Millers results.

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Complex organic molecules discovered in infant star system: Hints that building blocks of chemistry of life are universal

Date: April 8, 2015
Source: European Southern Observatory - ESO
Summary:


For the first time, astronomers have detected the presence of complex organic molecules, the building blocks of life, in a protoplanetary disc surrounding a young star. The discovery reaffirms that the conditions that spawned the Earth and Sun are not unique in the Universe.
 

Excerpt:

Astronomers have known for some time that cold, dark interstellar clouds are very efficient factories for complex organic molecules -- including a group of molecules known as cyanides. Cyanides, and most especially methyl cyanide, are important because they contain carbon-nitrogen bonds, which are essential for the formation of amino acids, the foundation of proteins and the building blocks of life.

Until now, it has remained unclear, however, if these same complex organic molecules commonly form and survive in the energetic environment of a newly forming solar system, where shocks and radiation can easily break chemical bonds.

By exploiting ALMA's [Atacama Large Millimeter/submillimeter Array] remarkable sensitivity [2] astronomers can see from the latest observations that these molecules not only survive, but flourish.

Importantly, the molecules ALMA detected are much more abundant than would be found in interstellar clouds. This tells astronomers that protoplanetary discs are very efficient at forming complex organic molecules and that they are able to form them on relatively short timescales [3].

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Evidence of key ingredient during dawn of life

Date: June 18, 2015
Source: University of North Carolina Health Care
Summary:

    Scientists have provided the first direct experimental evidence for how primordial proteins developed the ability to accelerate the central chemical reaction necessary to synthesize proteins and thus allow life to arise not long after Earth was created.

 

Excerpt:

"This doesn't yet solve the central chicken and the egg problem," Carter said. "Even the designed protozyme requires a ribosome to synthesize it and lead to protein creation. But what we've shown is that blueprints for life actually contained more information than anyone had realized because both strands of the ancestral gene were responsible for encoding the two classes of synthetases needed for the creation of proteins."

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Origins of life: New model may explain emergence of self-replication on early Earth

 

Date: July 28, 2015

 

Source: American Institute of Physics (AIP)

 

Summary:

 

One question of the origin of life in particular remains problematic: what enabled the leap from a primordial soup of individual monomers to self-replicating polymer chains? A new model proposes a potential mechanism by which self-replication could have emerged. It posits that template-assisted ligation, the joining of two polymers by using a third, longer one as a template, could have enabled polymers to become self-replicating.

 

Not one of the better articles on the subject, but this paragraph leaped out in particular, bolded mine:

 

Nearly every culture on earth has an origins story, a legend explaining its existence. We humans seem to have a deep need for an explanation of how we ended up here, on this small planet spinning through a vast universe. Scientists, too, have long searched for our origins story, trying to discern how, on a molecular scale, the earth shifted from a mess of inorganic molecules to an ordered system of life. The question is impossible to answer for certain -- there's no fossil record, and no eyewitnesses. But that hasn't stopped scientists from trying.

 

Give up biologist, give up abiogenesists. The question is impossible to answer for certain. Abandon hope all ye who enter here. This is the message that the pseudo-intellectuals have carried to nearly every corner of the globe. " "There are no absolutes," they chatter, blanking out the fact that they are uttering an absolute." Passed down from the Nazi's, the Relativists, emanating from the whirling Heraclitean flux of the Pragmatists, repeated by Dewey, obfuscated by Kant, embraced by the Utilitarians, the contradiction is blatant to those who see it.

 

There may be no fossil record, there may be no eyewitnesses. The evidence for existence is existence. The evidence for every other valid concept in existence is wrested from this vast sea of concretes that are whirling and spinning. When the deep need for explanations gets supplemented with the deep need for those explanations to be grounded in fact, necessity may then indeed bear her child.

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How yeast doubled its genome, by mating between species

 

Date: August 7, 2015

 

Source: PLO

 

Summary:

 

The common baker's yeast (Saccharomyces cerevisiae) was the first non-bacterial living thing to have its genome sequenced, back in 1996. However, when the sequence of that genome emerged it appeared that the scientists were seeing double -- the organism seemed to have two very different versions of many of its genes. How could this have happened?

 

Spiraling back to the opening post of this thread, and touching on the previous one,

 

"When we first saw the results of our study, we thought there had been some kind of mistake," explained Toni Gabaldón, the lead investigator of the study, head of the CRG Comparative Genomics Group and ICREA Research Professor. "Honestly, when the results are not what you expect and contradict what is established, the first thing you do is think that they were affected by some kind of problem. But once all the potential problems have been discarded, you begin to interpret the data objectively, without preconceived ideas, and to do real science. That's when we started to consider the different possible explanations and to work on a new idea,"

 

a paragraph later:

 

Gabaldón added, "It's one of those magical moments of research when, once you open your mind enough, you can surrender to the evidence in the data and discard what you had considered as a proven fact to adopt an entirely new paradigm, no matter how implausible it seems at first. Afterwards you reel in your new paradigm and see that it also explains other independent observations. Scientifically it has been a challenging and rewarding experience. "

 

I can only wonder at what Newton might have felt as he went through his materials and dotted the i's and crossed the t's.
I-love-it-when-a-plan-comes-together.jpg   or:   60847034.jpg

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Gabaldón added, "It's one of those magical moments of research when, once you open your mind enough, you can surrender to the evidence in the data and discard what you had considered as a proven fact to adopt an entirely new paradigm, no matter how implausible it seems at first. Afterwards you reel in your new paradigm and see that it also explains other independent observations. Scientifically it has been a challenging and rewarding experience. "

Surrendering to the evidence in the data is a sound approach, but to discard what you had considered as a proven fact has implications about the scientists approach to what constitutes as proven. If proven facts can be overturned with new evidence, the what has been identified is an earlier miss-integration. This highlights the need of a proper means of integration to prevent this from turning into a vicious circle. Miss-integration followed by new discoveries and then using the same methods that led to the first miss-integration to grope for a new integration. without examining the approach inevitably has to lead to more of the same. Edited by dream_weaver
formatting

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This thread started out with yeast and has turned toward abiogenesis since.

Life’s Secrets Sought in a Snowflake

Ratcliff and Travisano developed an easy way to force yeast to become multicellular. They grew the microbes in tubes and spun them in a centrifuge once a day. The largest cells or those that clustered together sank the fastest. Each day, they selected the fastest sinkers, challenging those cells to another round of the experiment. Over the course of 24 hours — roughly seven generations of yeast — the cells accumulated tens of thousands of mutations.

Then, a couple of weeks into the experiment, the composition of a few of the tubes suddenly changed. The cells began forming large clusters, and the silky solution of single cells transformed into grainy blobs. Within 100 yeast generations — about two weeks — the population had shifted almost entirely to snowflake yeast.

How does the centrifuge ultimately get factored out of understanding the process? Not addressed here, but it does serve as a catalyst in this procedure.

While typical yeast divides and disperses after each generation, snowflake cells divide and stick. Daughter cells cling to their mother like baby kangaroos. Mother and daughters then divide again and again, each producing another attached offspring.

The evolution of snowflake yeast created more than a mere clump of cells. Wild yeast strains sometimes produce a sticky protein on their surface, which makes the cells adhere to each other. Brewers like this sticky form, known as floc yeast, because it’s easier to remove it from newly brewed beer.

But snowflake yeast is quite different from flocs. Floc yeast cells divide and separate, then condense into a genetically diverse pile. Snowflake yeast grows in highly related clumps. It’s this difference that Ratcliff and others say distinguishes a simple blob of cells from a cohesive unit capable of evolving true multicellularity.

Similar experiments were also performed on algae with multi-cellular results that differed from their gravity-induced counterparts.

 

Descriptions like individual cells having to "surrender its will to survive" and "sacrificing themselves to benefit the whole" ring of the platonic view of society as an organism. There are also the "cheater [moochers?] cells, the single-celled equivalents of lazy roommates who eat everyone’s food but never go shopping or pay the bills." Brackets mine.

 

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From yeast to snowflake yeast. Life’s Secrets Sought in a Snowflake.

But snowflake yeast is quite different from flocs. Floc yeast cells divide and separate, then condense into a genetically diverse pile. Snowflake yeast grows in highly related clumps. It’s this difference that Ratcliff and others say distinguishes a simple blob of cells from a cohesive unit capable of evolving true multicellularity.

Whether snowflake yeast qualifies as truly multicellular or not is a difficult question to answer. There’s no clear dividing line between single-celled and multicellular organisms. Ratcliff likens the transition to what he calls the rich man, poor man problem. If you gathered everyone in the United States and lined them up according to wealth, the richest people would land at one end and the poorest at the other. If you just looked at these extreme ends of the spectrum, it would be easy to define the characteristics of the rich and the poor. But if you drove down the line of people, it would be impossible to define a strict point where the rich group ended and the poor group began. By this analogy, snowflake yeast is in the multicellular middle class.

So multicellular is a continuum? How might this have been explained using color as the continuum axis?

This is a fairly long article that does more to couch the questions than add much from the other tie-ins provided here.

On a parallel note, Creation of minimal cell with just the genes needed for independent life

Researchers have designed and synthesized a minimal bacterial genome, containing only the genes necessary for life, and consisting of just 473 genes. This advances the team's groundbreaking research published in 2010, in which they built and booted up the first self-replicating, synthetic bacterial cell, providing proof of principle that genomes can be designed in the computer, chemically made in the lab, and transplanted into a recipient cell to produce a new, self-replicating cell controlled only by the synthetic genome.

On 2/9/2016 at 6:24 AM, Boydstun said:

Life's Rocky Start

NOVA (2016)

I watched part of this when you originally put the link here. The video, there, has been moved behind DPTV Passport now.

 

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Rosetta’s comet contains ingredients for life

Date: May 27, 2016

Source: University of Bern

Summary:

Ingredients crucial for the origin of life on Earth, including the simple amino acid glycine and phosphorus, key components of DNA and cell membranes, have been discovered at Comet 67P/Churyumov-Gerasimenko.

Excerpt:

Another exciting detection by ROSINA made for the first time at a comet is of phosphorus. It is a key element in all living organisms and is found in the structural framework of DNA and RNA.

 

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Was the secret spice in primal gene soup a thickener?

Date: October 10, 2016

Source: Georgia Institute of Technology

Summary:

A little goo will do to get RNA and DNA to progress toward self-replication. Could some abundant ingredient have helped the precursors of genes become life molecules? Another indicator that little drama may have been necessary in chemical evolution.

A few selected highlights

For generations, scientists pursuing an answer performed experiments in water but hit a wall.

Georgia Tech researchers Christine He and Isaac Gállego overcame it by adding an off-the-shelf viscous solvent (the thickener). In separate experiments with DNA then RNA, the copying process proceeded.

The problem

In water alone, when cooling sets in, the long chains snap back into their helix structure so rapidly that there's no time for the matching process with the shorter chains. That snapping shut, which happens in both RNA and DNA, is called "strand inhibition," and in living cells, enzymes solve the problem of keeping the long chains apart while gene strands duplicate.

The analogous explanation

High viscosity has been known to slow down the movement of long strands of DNA, RNA and other polymers.

"It's a little like making them swim in honey," Grover said. Applying that to origin-of-life chemistry seemed obvious, because in prebiotic times, there probably were quite a few sticky puddles.

"In that solution, it gives the short nucleotides, which move faster, time to jump onto the long strand and piece together a duplicate of the long strand," researcher He said. In her experiments, it worked.

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On the origin of life: Studying how the first biomolecule self-replicated

Date: November 2, 2016

Source: American Chemical Society

Summary:

It's the ultimate chicken-or-egg conundrum: What was the "mother" molecule that led to the formation of life? And how did it replicate itself? One prominent school of thought proposes that RNA is the answer to the first question. Now researchers in this camp demonstrate RNA has more flexibility in how it recognizes itself than previously believed. The finding might change how we picture the first chemical steps towards replication and life.

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When a short piece of RNA (green) binds a nucleotide analogue (PZG, pink), three different binding modes are observed, suggesting canonical Watson-Crick is not the only possible mode of RNA self-recognition.
Credit: American Chemical Society

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Simple fats, amino acids to explain how life began

Date: January 12, 2017
Source: University of the Basque Country
Summary: A research group has explored how the chemical molecules that could have given rise to life were assembled.

. . . "life involves activity among a huge variety of molecules and components, a change of approach has been taking place in recent years and research that takes into account various molecules at the same time is gaining strength," — Kepa Ruiz-Mirazo, researcher in the Biophysics Unit and of the UPV/EHU's Department of Logic and Philosophy of Science.

. . . "Our group has expertise in research into membranes that are created in prebiotic environments, in other words, in the study of the dynamics that fatty acids, the precursors of current lipids, may have had. The Montpellier group for its part specialises in the synthesis of the first peptides. So when the knowledge of each group is put together, and when we experimentally blended the fatty acids and the amino acids, we could see that there was a strong synergy between them."

. . . "Life emerged out of these basic molecules; therefore, to study its origin we cannot start from the complex phospholipids that are found in today's membranes. We have demonstrated the formation of the first coming together and formation of chains on the basis of molecular precursors. Or to put it another way, we have demonstrated that it is possible to achieve diversity and complexity in biology by starting from chemistry."

. . . "Most likely we will never manage to find the answer to how life began, but we are working on it: all of us living beings on Earth have the same origin and we want to know how it happened."

[Bold emphasis mine] Ok, it is not defeat before they get where they are headed, but I can't help but think this is an albatross around the neck.

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