Posted on 11/21/2019 8:04:15 AM PST by LesbianThespianGymnasticMidget
An international team has found sugars essential to life in meteorites. The new discovery adds to the growing list of biologically important compounds that have been found in meteorites, supporting the hypothesis that chemical reactions in asteroids – the parent bodies of many meteorites – can make some of life’s ingredients. If correct, meteorite bombardment on ancient Earth may have assisted the origin of life with a supply of life’s building blocks. Image of asteroid Bennu This is a mosaic image of asteroid Bennu, from NASA’s OSIRIS-REx spacecraft. The discovery of sugars in meteorites supports the hypothesis that chemical reactions in asteroids – the parent bodies of many meteorites – can make some of life’s ingredients. Credits: NASA/Goddard/University of Arizona Full caption
The team discovered ribose and other bio-essential sugars including arabinose and xylose in two different meteorites that are rich in carbon, NWA 801 (type CR2) and Murchison (type CM2). Ribose is a crucial component of RNA (ribonucleic acid). In much of modern life, RNA serves as a messenger molecule, copying genetic instructions from the DNA molecule (deoxyribonucleic acid) and delivering them to molecular factories within the cell called ribosomes that read the RNA to build specific proteins needed to carry out life processes.
“Other important building blocks of life have been found in meteorites previously, including amino acids (components of proteins) and nucleobases (components of DNA and RNA), but sugars have been a missing piece among the major building blocks of life,” said Yoshihiro Furukawa of Tohoku University, Japan, lead author of the study published in the Proceedings of the National Academy of Sciences November 18. “The research provides the first direct evidence of ribose in space and the delivery of the sugar to Earth. The extraterrestrial sugar might have contributed to the formation of RNA on the prebiotic Earth which possibly led to the origin of life.” Artist's concept of meteors impacting ancient Earth Artist’s concept of meteors impacting ancient Earth. Some scientists think such impacts may have delivered water and other molecules useful to emerging life on Earth. Credits: NASA's Goddard Space Flight Center Conceptual Image Lab
“It is remarkable that a molecule as fragile as ribose could be detected in such ancient material,” said Jason Dworkin, a co-author of the study at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “These results will help guide our analyses of pristine samples from primitive asteroids Ryugu and Bennu, to be returned by the Japan Aerospace Exploration Agency’s Hayabusa2 and NASA’s OSIRIS-REx spacecraft.” model of ribose molecule with meteorite This is a model of the molecular structure of ribose and an image of the Murchison meteorite. Ribose and other sugars were found in this meteorite. Credits: Yoshihiro Furukawa
An enduring mystery regarding the origin of life is how biology could have arisen from non-biological chemical processes. DNA is the template for life, carrying the instructions for how to build and operate a living organism. However, RNA also carries information, and many researchers think it evolved first and was later replaced by DNA. This is because RNA molecules have capabilities that DNA lacks. RNA can make copies of itself without “help” from other molecules, and it can also initiate or speed up chemical reactions as a catalyst. The new work gives some evidence to support the possibility that RNA coordinated the machinery of life before DNA.
“The sugar in DNA (2-deoxyribose) was not detected in any of the meteorites analyzed in this study,” said Danny Glavin, a co-author of the study at NASA Goddard. “This is important since there could have been a delivery bias of extraterrestrial ribose to the early Earth which is consistent with the hypothesis that RNA evolved first.”
The team discovered the sugars by analyzing powdered samples of the meteorites using gas chromatography mass spectrometry, which sorts and identifies molecules by their mass and electric charge. They found that the abundances of ribose and the other sugars ranged from 2.3 to 11 parts per billion in NWA 801 and from 6.7 to 180 parts per billion in Murchison.
Since Earth is awash with life, the team had to consider the possibility that the sugars in the meteorites simply came from contamination by terrestrial life. Multiple lines of evidence indicate contamination is unlikely, including isotope analysis. Isotopes are versions of an element with different mass due to the number of neutrons in the atomic nucleus. For example, life on Earth prefers to use the lighter variety of carbon (12C) over the heavier version (13C). However, the carbon in the meteorite sugars was significantly enriched in the heavy 13C, beyond the amount seen in terrestrial biology, supporting the conclusion that it came from space.
The team plans to analyze more meteorites to get a better idea of the abundance of the extraterrestrial sugars. They also plan to see if the extraterrestrial sugar molecules have a left-handed or right-handed bias. Some molecules come in two varieties that are mirror images of each other, like your hands. On Earth, life uses left-handed amino acids and right-handed sugars. Since it’s possible that the opposite would work fine – right-handed amino acids and left-handed sugars – scientists want to know where this preference came from. If some process in asteroids favors the production of one variety over the other, then maybe the supply from space via meteorite impacts made that variety more abundant on ancient Earth, which made it more likely that life would end up using it.
The research was funded by a Japan Society for the Promotion of Science KAKENHI (science grant), the National Institutes of Natural Sciences Astrobiology Center, Japan, the Institute of Low Temperature Science, Hokkaido University, the Simons Foundation, and the NASA Astrobiology Institute, Goddard Center for Astrobiology. Jason Dworkin and Danny Glavin are members of the Goddard Center for Astrobiology team.
I never go on a thread and comment that these people are mistaken where the discussion includes dinosaurs and humans being cohabitant at some point in our supposed 5000 year history. Why you guys just don’t show the same respect to people who believe differently is beyond me. Shows a definitive lack of class commenting.
Well, are Mars bars harmful to Americans? If not, why don’t we have them?
Who ever heard of a Meteor bar?
“Wonder what the mathematical probabilities of that are?”
Oh, don’t worry about that. If the probability is too small, they’ll just say the universe must be a few billion years older than they thought.
It’s easy to win the evolutionary lottery if you can give yourself an unlimited number of tickets!
Sounds like the Olestra “fat free fat” debacle.
It is a disaccharide formed from one molecule each of the simple sugars (monosaccharides) fructose and galactose. Lactulose is not normally present in raw milk, but is a product of heat processes:[23] the greater the heat, the greater amount of this substance (from 3.5 mg/l in low-temperature pasteurized milk to 744 mg/l in in-container sterilized milk).[24] It is produced commercially by isomerization of lactose.
Lactulose is metabolized in the colon by bacterial flora to short-chain fatty acids, including lactic acid and acetic acid. These partially dissociate, acidifying the colonic contents (increasing the H+ concentration in the gut).[16] This favors the formation of the nonabsorbable NH+
4 from NH3, trapping NH3 in the colon and effectively reducing plasma NH3 concentrations. Lactulose is therefore effective in treating hepatic encephalopathy.[25][needs update] Specifically, it is effective as secondary prevention of hepatic encephalopathy in people with cirrhosis.[26] Moreover, research showed improved cognitive functions and health-related quality of life in people with cirrhosis with minimal hepatic encephalopathy treated with lactulose.[27]
See #21
It’s an open forum, and you know there are plenty of people here who have differing opinions on the subject. What do you expect?
You can go post the articles on some subreddit where nobody will disagree with you. Or maybe you can do like the Catholics do on the Religious Forum and make a [Caucus] tag so nobody with a different viewpoint can post, or they’ll feel the wrath of the mods.
I don’t really see the appeal of that, but I guess you could try it.
‘I never go on a thread and comment that these people are mistaken where the discussion includes dinosaurs and humans being cohabitant at some point in our supposed 5000 year history.’
well, a dinosaur fossil was discovered near a mountain in Turkey, and a piece of wood was also discovered somewhere in the basic area, so, Noah...
‘Why you guys just don’t show the same respect to people who believe differently is beyond me’
organized hierarchic entities,(governments, schools and churches) have not gotten their chops through being tolerant of opposing notions; people can’t accrue influence and power by permitting unfettered apostasies to circulate...
‘It’s easy to win the evolutionary lottery if you can give yourself an unlimited number of tickets!’
it’s even easier to win that lottery if you buy just one ticket, and reject all the others as bogus right from the start...
Your post reminded me of the reviews for Harbo sugar-free gummy bears on Amazon.
Probably Sorbitol. That is some nasty stuff too. Not quite as violent in its exit as L-Glucose, but still bad.
So the Dinosaurs drowned?
I thought all animals, one of each sex got on the ark...
Looked it up. Contains Maltitol Syrup... Gut bacteria munch on it, so no... more gentile.
Toooo funny!! :)
right/left handed sugars occur naturally at about 60/40 ratio. If you remove one type from a sample the remaining type reverts to the same previous ratio.
Only in proteins, DNA and such is it only righthanded.
I don’ t wish to insult one’s intelligence, but even given the “inestimable numbers of meteorites”, life, with its right-from-the start ability to survive, subsist and reproduce is a bit of a stretch, don’t ya think?
Math one of your strong suits?
Think “Creator”.
Yeah, okie dokie, so did they retrieve the object in space where it would be uncontaminated from stuff on earth? Yeah, nope. So, how long has it been hanging around a planet full of life with things that like nooks and crannies? But, this IS science.
Hence my comment about left handed sugars. They don’t occur naturally on earth.
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