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Part1 (up to Ryan knows)
Task1. Match the words/expressions in column A to the explanations in column B.
A B
1. to transfer to doubt
2. to challenge reduction in rank or status
3. to fly in the face causing doubt
4. trace insane
5. demotion afterwards
6. dubious to question the truth, value, or authority.
7. nuts to include (something) as a necessary or integral part or result
8. subsequently increasing
9. to withdraw to happen, to take place
10. to involve to remove or take away (something) from a particular place or position
11. enhancing to move from one place to another
12. to occur a very small quantity, esp. one too small to be accurately measured
13. to question to be openly at variance with (what is usual or expected
Task2. Say if the following is true, false or nor mentioned.
1. The scientific community is believed to support the results of the research.
2. For over a century, the predominant view in memory research has been that the engram, the physical substrate of memory, is stored at the synapse.
3. The new research questions the wide spread beliefs about where and how memories are stored in the brain.
4. Glanzman understands that his theory about synapses playing a smaller or no part in memory will not be accepted by the scientific community.
5. The experiment was replicated in larger animals with a more complex brain.
6. The idea of his experiments was to shock the marine snail Aplysia californica with strong electric pulses.
7. Control snails that were injected the RNA of snails that were not irritated by electricity did not exhibit any changes in behavior.
8. It is important to emphasize that these findings do not suggest that memory is encoded by RNA
9. A Trinity College scientist says that memories are stored by new synaptic connections, not by strengthening existing ones.
Task3. Answer the following questions.
1. Why is memory transfer from one animal to another by RNA injections so important?
2. What is necessary for the experiment to be valid?
3. Why do most scientists question the results?
4. What was the main idea of the experiment?
5. How did the neurons of shocked snails change their features?
6. Where are according to Glanzman memories stored?
7. What theory did the results question?
8. How is the idea accepted by other scientists?
9. Why are some scientists called rebels?
Part2
Task1. Match the words in column A to the explanations in column B
A B
1. to eclipse to seem
2. to harken(hark) back to have an idea that is likely to lead to an important discovery
3. to replicate to understand
4. to be onto something to find something or someone that you have been looking for
5. derision to overshadow or surpass in importance, power, etc •
6. chase down to make an exact copy of; reproduce
7. to figure out to return to an earlier subject
8. to appear mockery , ridicule
Task2 Say whether the following is true, false or not mentioned
1. Though other laboratories were able to do the experiment and have the same results, MacConnel’s research was laughed at.
2. A Trinity College scientist does not agree with Glanzman’s hypothesis.
3. He thinks the most basic behavioural responses involve some kind of switch in the animal and there is something in the soup that Glanzman extracts that is hitting that switch."
4. The experiment was reproduced with untrained worms which after cannibalizing trained worms showed no difference in behaviour.
5. One of McConnell’s students was never given a permanent university position because his work was questioned.
6. After growing new heads the trained worms which were beheaded exhibited the same behavior as before.
7. And though memory RNA is still believed to be a myth, a recent research has confirmed that these worms’ memories do work in astoundingly bizarre ways.
8. Glazman still doubts if MacConnel hypothesis is correct, but he thinks he and his colleage had an idea that was likely to lead to an important discovery
9. The mechanism behind memory is still hard to understand , which can partly be explained by too much emphasis on synaptic strength.
10. It is not easy to do research in the memory sphere if you do not agree with accepted theories.
‘Artificial DNA Base Pair Expands Life’s Vocabulary
By Nathaniel Scharping
Scientists have taken another step towards putting two additional letters in the dictionary of life to work.
Researchers at the Scripps Institute have engineered cells to successfully transcribe a brand new artificial DNA base pair and make a never-before-seen protein with it. The breakthrough is part of an effort to expand the library of amino acids that animal cells can work with, potentially leading to the creation of compounds entirely different from those life can produce now.
The work was led by Floyd Romesberg, an associate professor of chemistry at Scripps, and adds to his 20-year effort to create synthetic DNA “letters.” DNA is currently comprised of four nucleotides, or letters: C, G, A and T—C binds to G, A binds to T. These couplings, or base pairs, comprise DNA as we know it. Romesberg and colleagues created two completely new letters, he calls them X and Y, and inserted them into a cell’s genome. Instead of four base pairs, the “semi-synthetic” cell now has six.
This drastically increases the number of codons — you can think of them as genetic “words” — and therefore, the number of things cells can make. Currently, there are 64 different triplet combinations of C-G and A-T possible. Three of those are stop codons, and many combinations are redundant, leaving our bodies with just 20 codons, or words, to make compounds with. Add in another base pair, and the number of potential words increases to 216. That more than triples the total, and the potential applications are vast.
“We will never need more codons,” he says. “We can now write more information in cells than we’d ever want to use.”
Expanding Vocabulary
In 2014, Romesberg successfully coaxed a cell to incorporate his custom X and Y base pair to its DNA, and found that it would remain there as long as he kept supplying the nucleotides. He’s now shown, in a Nature paper published Wednesday, that cells can not only hold on to the new base pairs, but they can use custom RNA sequences to transcribe codons with these new base pairs into something tangible.
Transcription is the process by which RNA copies bits of DNA and uses them to make things our bodies need. With new base pairs, the cells could make new codons, and those new genetic words held the blueprints for compounds that were previously impossible for cells to make. What’s more, the cells transcribed the new codons just as efficiently as the natural ones.
Adding the base pair to DNA demonstrated that storage was possible, he says, his latest work shows that the information can be retrieved works, and now he must show that cells can actually use the new compounds they make to do something interesting.
Romesberg provides a demonstration of this by adding in two new amino acids to a common fluorescent protein called GFP using E. coli bacteria. Bacterial cells with the extra base pair were able to produce amino acids that showed up in the flowing cells, proving that a new compound could make it from DNA to reality in a cell. The potential applications go far beyond glowing proteins, of course. Animal cells are currently only able to produce a finite set of things, limited by the number of genetic words they have to work with.
“We are making amino acids that are not normally made, cells are not capable of storing the information to make them,” Romesberg says.
This could mean new medicines, new nanomaterials, new reagents for chemical reactions. It could also eventually mean cells that can carry out functions no cell today can.
Don’t Panic
With the mention of new types of cells, thoughts of nightmare science-fiction scenarios are inevitable. Romesberg says that there are significant barriers to these cells ever making it outside the lab, however.
“One thing that’s really important to keep in mind is that we have a fail-safe built into this,” he says. “X and Y are unnatural nucleotides, [they] are not made by the cell. And this is not a “Jurassic Park” situation because these are man-made things.”
In his previous work getting cells to add the X and Y nucleotides into their DNA, he found that the cells immediately purged the base pair from the DNA as soon as he stopped giving it to them. Because these nucleotides aren’t natural, animal cells can’t manufacture them. The only way to keep them in a cell’s DNA is to keep them in the lab where they can be constantly supplied with new materials.
“They are not trivial molecules, they’re unlike anything a cell already makes,” Romesberg says. “It would have to assemble two complete new pathways out of something from which it has nothing similar to.”
For applications like creating new drugs, this would work fine because researchers could just keep giving them the supplies they need. If they escaped, however, the synthetic nucleotide would disappear from their genome.
“For a long time, people thought that the molecules of life were somehow different and privileged relative to the molecules of things that weren’t alive,” Romesberg says. “Maybe the molecules of life aren’t as special as we thought. And maybe a chemist can come in and design things that function alongside them. Maybe life is not the perfect solution, maybe life is a solution.”
‘Artificial DNA Base Pair Expands Life’s Vocabulary
Tasks
Task1. Find the following words/ expressions in the text.
1. a sudden, dramatic, and important discovery or development;
2. wholly;
3. consist of; be made up of;
4. place, fit, or push (something) into something else;
5. no longer needed or useful; superfluous;
6. to make something do something by dealing with it in a slow ,patient and careful way;
7. to get or bring (something) back from somewhere;
8. on the other side of a place or barrier ;
9. limited in size or extent;
10. finally;
11. that cannot be prevented or avoided
Task2.Say whether the following is true, false or not mentioned.
1. Scientists managed to create new proteins with the help of artificial DNA and include them into rats metabolism.
2. This experiment makes cells produce new things by increasing the number of “genetic words”
3. The number of codons (six instead of four) is enough now to write more information in cells than will ever be necessary.
4. While transcribing the cells didn’t see any difference between the natural codons and the new ones.
5. The cells constitute a “stable form of semi-synthetic life” and “lay the foundation for achieving the central goal of synthetic biology: the creation of new life forms and functions.
6. This experiment is very dangerous and can get out of control leading to the appearance of new animals.
7. Its results can be used for biological warfare helping create new microbes and viruses.
8. The scientists are sure there is not much difference between the molecules of life and the molecules of unliving things
9. The artificial X-Y base pair is formed via hydrophobic attraction between the two elements, rather than hydrogen bonding.
Task3. Answer the following questions.
1. The article mentions a breakthrough. What breakthrough is meant and why is it a breakthrough?
2. Why is the number of codons so important?
3. Can we say that the more codons the better it is? Why? Why not?
4. What’s the point of having six base pairs instead of four?
5. What experiment did Romesberg do in2014?
6. What did Romesberg prove now?
7. How can the discovery be used?
8. What prevents the new cells from escaping and the experiment from getting out of control?
9. Do you think in future this obstacle will be removed and we shall have animals with six base pairs or artificial life?
Дата: 2019-02-02, просмотров: 235.