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NASA Ames Reproduces the Building of Life in Laboratory

Autor por Emilio Silvera    ~    Archivo Clasificado en Noticias    ~    Comentarios Comments (2)

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Nuestro contertulio jccazorla39, me envía un correo que est5ima de interés para que todos lo podamos leer, y, habiéndolo hecho, resulta que he decidido pasarlo para todos. La fuente es la propia NASA.
Scientists simulate space in Ames Astrochemistry Lab
Left to right: Ames scientists Michel Nuevo, Christopher Materese and Scott Sandford reproduce uracil, cytosine, and thymine, three key components of our hereditary material, in the laboratory.
Image Credit:
NASA/ Dominic Hart

NASA scientists studying the origin of life have reproduced uracil, cytosine, and thymine, three key components of our hereditary material, in the laboratory.  They discovered that an ice sample containing pyrimidine exposed to ultraviolet radiation under space-like conditions produces these essential ingredients of life.

Pyrimidine is a ring-shaped molecule made up of carbon and nitrogen and is the central structure for uracil, cytosine, and thymine, which are all three part of a genetic code found in ribonucleic (RNA) and deoxyribonucleic acids (DNA). RNA and DNA are central to protein synthesis, but also have many other roles.

Ames Astrochemistry Lab UV lamp
An ice sample is held at approximately -440 degrees Fahrenheit in a vacuum chamber, where it is irradiated with high energy UV photons from a hydrogen lamp. The bombarding photons break chemical bonds in the ice samples and result in the formation of new compounds, such as uracil.
Image Credit:
NASA/Dominic Hart

“We have demonstrated for the first time that we can make uracil, cytosine, and thymine, all three components of RNA and DNA, non-biologically in a laboratory under conditions found in space,” said Michel Nuevo, research scientist at NASA’s Ames Research Center, Moffett Field, California.  ”We are showing that these laboratory processes, which simulate conditions in outer space, can make several fundamental building blocks used by living organisms on Earth.”

An ice sample is deposited on a cold (approximately –440 degrees Fahrenheit) substrate in a chamber, where it is irradiated with high-energy ultraviolet (UV) photons from a hydrogen lamp.  The bombarding photons break chemical bonds in the ices and break down the ice’s molecules into fragments that then recombine to form new compounds, such as uracil, cytosine, and thymine.

NASA Ames scientists have been simulating the environments found in interstellar space and the outer Solar System for years.  During this time, they have studied a class of carbon-rich compounds, called polycyclic aromatic hydrocarbons (PAHs), that have been identified in meteorites, and which are the most common carbon-rich compound observed in the universe.  PAHs typically are structures based on several six-carbon rings that resemble fused hexagons, or a piece of chicken wire.

The molecule pyrimidine is found in meteorites, although scientists still do not know its origin.  It may be similar to the carbon-rich PAHs, in that it may be produced in the final outbursts of dying, giant red stars, or formed in dense clouds of interstellar gas and dust.

“Molecules like pyrimidine have nitrogen atoms in their ring structures, which makes them somewhat wimpy.  As a less stable molecule, it is more susceptible to destruction by radiation, compared to its counterparts that don’t have nitrogen,” said Scott Sandford, a space science researcher at Ames.  ”We wanted to test whether pyrimidine can survive in space, and whether it can undergo reactions that turn it into more complicated organic species, such as the nucleobases uracil, cytosine, and thymine.”

Nucleobases structures
Pyrimidine is a ring-shaped molecule made up of carbon and nitrogen and is the central structure for uracil, cytosine, and thymine, which are found in RNA and DNA.
Image Credit:
NASA
Nucleobases cytosine thymine image
The ring-shaped molecule pyrimidine is found in cytosine and thymine.
Image Credit:
NASA

In theory, the researchers thought that if molecules of pyrimidine could survive long enough to migrate into interstellar dust clouds, they might be able to shield themselves from destructive radiation.  Once in the clouds, most molecules freeze onto dust grains (much like moisture in your breath condenses on a cold window during winter).

These clouds are dense enough to screen out much of the surrounding outside radiation of space, thereby providing some protection to the molecules inside the clouds.

Scientists tested their hypotheses in the Ames Astrochemistry Laboratory.  During their experiment, they exposed the ice sample containing pyrimidine to ultraviolet radiation under space-like conditions, including a very high vacuum, extremely low temperatures (approximately –440 degrees Fahrenheit), and harsh radiation.

They found that when pyrimidine is frozen in ice mostly consisting of water, but also ammonia, methanol, or methane, it is much less vulnerable to destruction by radiation than it would be if it were in the gas phase in open space.  Instead of being destroyed, many of the molecules took on new forms, such as the RNA/DNA components uracil, cytosine, and thymine, which are found in the genetic make-up of all living organisms on Earth.

“We are trying to address the mechanisms in space that are forming these molecules.  Considering what we produced in the laboratory, the chemistry of ice exposed to ultraviolet radiation may be an important linking step between what goes on in space and what fell to Earth early in its development,” said Christopher Materese, another researcher at NASA Ames who has been working on these experiments.

“Nobody really understands how life got started on Earth. Our experiments suggest that once the Earth formed, many of the building blocks of life were likely present from the beginning.  Since we are simulating universal astrophysical conditions, the same is likely wherever planets are formed,” says Sandford.

Additional team members who helped perform some of the research are Jason Dworkin, Jamie Elsila, and Stefanie Milam, three NASA scientists at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

The research was funded by the NASA Astrobiology Institute (NAI) and the NASA Origins of Solar Systems Program.  The NAI is a virtual, distributed organization of competitively-selected teams that integrates and funds astrobiology research and training programs in concert with the national and international science communities.

Ruth Marlaire
Ames Research Center, Moffett Field, Calif.
650-604-4789
ruth.marlaire@nasa.gov

To receive local-only NASA Ames news, email local-reporters-request@lists.arc.nasa.gov with “subscribe” in the subject line. To unsubscribe, email the same address with “unsubscribe” in the subject line.


  1. elektronik sigara c6 plus, el 22 de junio del 2016 a las 4:41

    elektronik sigara c6 plus…

    NASA Ames Reproduces the Building of Life in Laboratory : Blog de Emilio Silvera V….

 

  1. 1
    Emilio Silvera
    el 9 de marzo del 2015 a las 12:08

    No cabe ninguna duda de que el interés del trabajo merece la pena. Todos sabemos de cómo se llegan a formar los ingredientes de la vida que, cada día, son decubiertos en el Laboratorio, o, incluso, en el Espacio Interestelar donde han encontrado también, aminoácidos necesarios para la vida.

    Las moléculas y compuestos al ser bombardeados por la radiación ultravioleta, se transforman, se convierten en otros ingredientes y sustancias, y, así tuvo que haber sucedido en la Tierra primigenia que, al ser bombardeada por la radiación proveniente del Espacio Exterior (sin atmósfera .o poca- y sin capa de Ozono), tuvieron el efecto de transformar elementos allí presentes que germinaron en una siopa primordial de protoplasma vivo, de la que surgió aquella primera célula replicante que nos trajo hasta nosotros, es decir, partiendo de la “materia inerte” se llegó a la materia animada y también, hasta los pensamientos.

    Está claro que, la Naturaleza que es sabia, utiliza los comportamientos de todos los elementos y sustancias que existen para que, cada uno de ellos, en su momento oportuno, desempeñen el “papel” que se les ha dado en este gran escenario del Universo, y, de esa manera, moléculas de increíble compljidad son detectadas en las Nubes de Gas y Polvo que conocemos por Nebulosas y que, pasados algunos millones de años, se transforman, por efecto de la Gravedad y de los vientos solares, en nuevas estrellas, nuevos mundos, y… ¡Nuevas formas de Vida!

    El trabajo nos muestra un buen ejemplo de cómo son las cosas y nos acerca, un poco más, a esa verdad que incansables buscamos del Origen de la Vida.

    Responder

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