During scientists' attempts to understand how the building blocks of RNA were formed on Earth, the creation of guanine, the letter G in the four-letter code of life, proved to be a special challenge. While the other three bases of RNA (adenine, A, cytosine, C and uracil, U) can be prepared by heating a simple precursor compound in the presence of certain natural catalysts, the base guanine could not be produced in this way.
By adding ultraviolet radiation to a probiotic model reaction (pre-life), researchers from the Georgia Institute of Technology and the University of Rome discovered a way in which the missing guanine base may have been formed. They also found that it is possible that the bases of RNA were created in an easier way than the one thought about until now - which suggests that the appearance of life on Earth was not such a complex process, after all. The findings of this study were published in the scientific journal ChemBioChem.
Understanding the emergence of life is one of the greatest scientific challenges. There is considerable evidence that the development of life went through an early stage in which RNA splicing played a more central role, before the appearance of DNA splicing and enzymes. Recent efforts to understand the probiotic creation of the building blocks of RNA have focused on the chemical formamide (H2NCOH) as a possible starting material for the preparation of RNA bases because it contains all four necessary elements - carbon, hydrogen, oxygen and nitrogen - and thanks to its stability, its degree of activity and its low volatility, relative to water. Previous publications have shown that these nucleic acid components - except for guanine - can be prepared by heating formamide to 160 degrees Celsius in the presence of mineral catalysts.
In the published article, the researchers show, for the first time ever, that guanine can be prepared by exposing a formamide solution to ultraviolet radiation during heating. The yield of guanine increased significantly when minerals were added to the process. In addition, the yield of adenine and its close derivative (hypoxanthine) increased following the addition of ultraviolet radiation to the heating process - an increase of 15 orders of magnitude in the yield of adenine.
"These findings potentially alleviate the requirements and reactions necessary for the emergence of life, as it is not necessary for the formamide particles to be in contact with a particular type of rock during heating in the prebiotic Earth, if they can be exposed to direct sunlight during heating," said Nicholas Hud, professor of chemistry. and biochemistry at the University of Georgia.
The study demonstrates that guanine, adenine, and hypoxanthine can be prepared at lower temperatures than previously reported, even in the absence of minerals, as long as irradiation continues.
"For these experiments, we built a very simple reaction chamber containing an inexpensive radiation source with a wavelength of 254 nanometers to simulate the conditions that may have existed in the early days of the Earth," added one of the researchers. "We didn't need particularly sophisticated experimental systems or an expensive laser; However, we did use a sophisticated mass spectrometer to analyze the composition of the resulting complex chemical mixture."
The researchers conducted their experiments by heating formamide to a temperature of 130 degrees Celsius - 30 degrees less than the previous experiments - and exposing it to ultraviolet radiation.
"Our research allowed us to consider the existence of a different type of "primordial soup" from the one that was accepted in the past as the source of the appearance of life," explains the researcher. "Our probiotic model response is interesting because it is likely that most aspects of the process could have existed on the ancient Earth and that it alleviates chemical constraints."
The researchers suggest that aqueous reservoirs containing small amounts of formamide may have existed on the ancient Earth. During periods of drought and heat, evaporation of water from them may have produced concentrated solutions of formamide and exposed mineral surfaces covered with these solutions.
By conducting additional experiments at 100 degrees Celsius with solutions of water and formamide, the researchers verified that this "drying reservoir" model could produce formamide solutions capable of producing the same compounds found in their earlier experiments.
"While a lot of chemistry is required to better understand the creation of biological molecules necessary for life, these direct reactions that occur due to the mutual amplification of thermal and photochemical processes suggest to us that the chemical and environmental requirements for the creation of life are probably less rigid than we thought," the researcher points out.
6 תגובות
To Reuven (3):
Whether you like it or not, the riddle of the process of the formation of life (or at least the possibility of life forming completely naturally without needing any crutches of the type of an external supernatural force) is getting closer to its solution in ever-increasing steps (in giant steps indeed if you look at the discoveries of the last century).
When you say "it is better not to be solved at all" I assume you are saying this because of the possible negative consequences that involve controlling this type of knowledge. I assume that if you were making the decisions at the time when the stone knife was invented, or the way to light a fire was found, you would have dismissed this knowledge from the same argument. Fortunately for us, the person who did run the business in those days thought that knowledge, despite the potential risks it entails (such as using the stone knife to cut an annoying neighbor or burning down the straw hut from carelessly lighting the fire) is still a positive thing, not to say necessary, in the end Therefore, apart from the disclosures, we also have the responsibility to minimize the possible risks and damages that may occur with his pens. Man has proven throughout history that he is capable of shocking things in their immorality and that too without needing particularly advanced technology, which probably implies that the problem is not in technology or knowledge themselves...
The only way to deal with the possible risks that new knowledge raises is to investigate and get to know that field as well as possible, an approach of closing one's eyes, on the other hand, is the most dangerous because once it is understood that obtaining this knowledge is possible, it is only a matter of time until this knowledge is obtained (unless Yes, the whole world will be unanimous and cooperate fully without exception, something that clearly does not exist even in much simpler things) and from this point of view I would like to be the first to know things and not the last after it is already too late. Ignorance is a kind of prison which is a luxury in this world. I certainly agree that extreme caution should be taken in areas that can have a far-reaching effect on our existence, but I do not agree with a way of thinking that holds that we are too weak or too stupid to understand how the world we live in works. Study the details carefully so that you can clearly distinguish which demon in the closet is to be guarded against and which demons are in your head to be guarded against no less.
Reuben,
I do not agree with your position. Anmak:
First: scientific progress of any kind is not a correlative of lawlessness and destruction. - the opposite.
It is forbidden, and it is not possible to stop scientific research.
On the other hand - it is mandatory, and this is possible - to channel the research results and monitor the ways of their use according to a proper moral code and through sufficient regulatory vigilance.
Second - regarding the question of the study of the origin of life at the level of religious principle:
- Of course, like everything in our world, it is a process that has a principle of action and a physical expression.
Can a person see in this process an expression of a deliberate or intervening will of a divine being - as part of a general worldview that sees reality and every part of it as a field of divine presence and supervision. Indeed, it seems that in any possible process of spontaneous life creation, the probability of life creation is so tiny that the practical programming for spontaneous creation is actually nullified; And from this point of view, that person can be impressed by the phenomenon of the creation of life and its existence as a clear and impressive manifestation of divine presence and providence.
But it is clear that this does not eliminate the chemical-physical external manifestation of the process. Therefore, the opposition to scientific research of the creation of life must be ruled out, also from the principled religious angle.
Reuven is right, see Spider-Man 2:
"With great power comes great responsibility".
The riddle of the process of the formation of life will not be solved easily. It is better not to be solved at all. Since the revelation may tempt
the person, to conduct failed experiments out of curiosity, the results of which will be devastating.
Luke:
Thanks for the completion (this shows that it is often worthwhile for those who are interested to look for more information in the original article)
Formamide:
http://en.wikipedia.org/wiki/Formamide