Диссертация (1173136), страница 53
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Read the extract and find new and well-known information.Every summer, Shimomura would sail out into the bay of Friday Harbor, San Juan Island,Washington, when the sea became thick with jellyfish. During 1961, he extracted the faintly glowingrings from around 10,000 of the mouse-sized jellyfish and squashed them through a filter. Afterisolating a protein from the glowing ’squeezate’, Shimomura was surprised to find that it emittedblue light, not green.
This, it turned out, was aequorin - a protein that produces blue light in thepresence of calcium ions212.Ex. 18. Read the extract and underline word combinations that express truthfulness ofinformation.a) Prasher was the first to envisage how GFP might function as a fluorescent tag. Being small enoughto not hinder the action of other proteins and responsive to ultraviolet light, Prasher reasoned thatGFP would be perfect for tracking cancer cells. By 1992, he had isolated the GFP gene and publisheda paper detailing the sequence of the 238 amino acids that make up the protein 213.b) One thing Tsien had not yet managed to do was produce light towards the red end of the spectrum- this is very useful as it can penetrate biological tissue more easily.
The turning point came whenSergey Lukyanov at the Shemyakin Institute of Bioorganic Chemistry in Moscow, Russia,discovered a GFP-like protein in coral, which was termed DsRED214.c) The green fluorescent protein can donate electrons in a process powered by light, to molecules thatlike to accept electrons. This is what Konstantin Lukyanov of the Shemyakin and OvchinnikovInstitute of Bioorganic Chemistry in Moscow, Russia, and his colleagues found out by accident 215.d) This year's Nobel Prize in Chemistry rewards the initial discovery of GFP and a series ofimportant developments which have led to its use as a tagging tool in bioscience.
By using DNAtechnology, researchers can now connect GFP to other interesting, but otherwise invisible, proteins.Там жеPrasher D. [Электронный ресурс]. – Режим доступа: https://www.conncoll.edu/ccacad/zimmer/GFPww/prasher.html212Nobel Lecture by Osamu Shimomura. Discovery of Green Fluorescent Protein. [Электронный ресурс]. – Режимдоступа:http://nslc.wustl.edu/courses/Bio1810/readings/Nobel%20shimomura_lecture.pdf (последняя дата обращения05.12.2017 г.)213Prasher D. [Электронный ресурс].
– Режим доступа: https://www.conncoll.edu/ccacad/zimmer/GFPww/prasher.html214Lewis Brindley A glowing green Nobel. Chemistry World. 29 October 2008. [Электронный ресурс]. – Режимдоступа: https://www.chemistryworld.com/feature/a-glowing-green-nobel/3004465.article215Katharine Sanderson Green glow deciphered. Published online 25 April 2009 | Nature | doi:10.1038/news.2009.401[Электронный ресурс]. – Режим доступа: http://www.nature.com/news/2009/090425/full/news.2009.401.html210211271This glowing marker allows them to watch the movements, positions and interactions of the taggedproteins216.Ex.
19. Read the extract from Interview with Roger Y. Tsien and underline expressions thatdescribe unsolved problems for scientists.[Roger Tsien] And that's a strange paradoxical phenomenon because we discovered that almost anymutation of one amino acid right next to the chromophore will shift it to being all of one or all of theother – either all UV or all blue. And most people for biological purposes would rather have all blue.Occasionally it's useful to have nothing but UV, and there's I think only one amino acid that willmake it either UV or blue.
And when it is UV it is unable to do the energy transfer from aequorin.And therefore the jellyfish would presumably glow blue. And one of the great mysteries that I'venever figured out is why the jellyfish chose the only amino acid that would compromise, and beschizophrenic, and be partly UV and partly blue in its absorbance. And it could have so easily shiftedit to all of one or all of the other. And instead it's preserved this split character. We don't know why.But that is a nuisance for anyone else using it pretty much. Almost anyone else.[Adam Smith] Apparently it doesn't bother the jellyfish in evolutionary terms – it gets on fine. So ...[Roger Tsien] Well, we have even wondered if there are times the jellyfish wants to turn on GFP'sability to switch blue into green, and there are times it wants to turn it off.
But I'm not enough of anecologist to ... Since we don't even know why it wants to glow, and if it does want to glow why doesit sometimes want to glow green, then I cannot answer the question. I'm certainly not going toanswer the question of why doesn't it always want to glow green?217в) Упражнения, целью которых является осуществление операции стяженияотдельных элементов текста:Ex.
20. Read the extracts from the lecture by a Nobel Laureate, Osamu Shimomura (a,b) andthe article by Lewis Bridley (c) and find parallel constructions (for example, I tried, I did, Imade) and repeated words, make the underlined text shorter:a) At the time, it was a common belief that the light of all bioluminescent organisms was producedby the reaction of luciferin and luciferase. Therefore, we tried to extract luciferin and luciferase fromthe rings of the jellyfish.
We tried every method we could think of, but all our efforts failed. Afteronly a few days of work, we ran out of ideas218.b) We started to collect jellyfish at 6 AM, and a part of our group began to cut off the rings at 8 AM.We spent all afternoon extracting aequorin from the rings. Then, we collected more jellyfish in theevening, 7 PM to 9 PM, for the next day. Our laboratory looked like a jellyfish factory, and wasfilled with the jellyfish smell219.c) The secret lies in the way GFP folds itself - wrapping up into a barrel-like shape, with three keyamino acids (a serine-tyrosine-glycine sequence) folded tightly together in the centre220.Press Release [Электронный ресурс]. – Режим доступа: https://www.nobelprize.org/prizes/chemistry/2008/pressrelease/(дата обращения 29.09.2018)217Interview with Roger Y.
Tsien [Электронный ресурс]. – Режим доступа:https://www.nobelprize.org/nobel_prizes/chemistry/laureates/2008/tsien-telephone.html (последняя дата обращения05.12.2017 г.)218Nobel Lecture by Osamu Shimomura. Discovery of Green Fluorescent Protein. [Электронный ресурс]. – Режимдоступа: http://nslc.wustl.edu/courses/Bio1810/readings/Nobel%20shimomura_lecture.pdf(последняя дата обращения 05.12.2017 г.)219Там же220Lewis Brindley A glowing green Nobel.
Chemistry World. 29 October 2008. [Электронный ресурс]. – Режимдоступа: https://www.chemistryworld.com/feature/a-glowing-green-nobel/3004465.article216272Ex. 20. Key: a) Therefore, I tried day and night to reversibly inhibit luminescence with various kindsof inhibitors of enzymes and proteins; b) It took us almost the whole day to collect jellyfish andextract aequorin from the rings. // We spent all day collecting jellyfish and extracting aequorin fromthe rings.; c) The secret lies in the way GFP wraps up itself in the shape of a cylinder, with three keyamino acids (a serine-tyrosine-glycine sequence) folded tightly together in the centre.Ex.
21. Read the extracts from the lecture by a Nobel Laureates, Osamu Shimomura and theinterview by Roger Tsien, find sentences expressing similar meaning, join them using thepredicate of one of the sentence.a) Since the emission of light means the consumption (loss) of active bioluminescent substance, theextraction of bioluminescent substances from light organs must be performed under a condition thatreversibly inhibits the luminescence reaction.
Therefore, I tried to reversibly inhibit luminescencewith various kinds of inhibitors of enzymes and proteins. I tried very hard, but nothing worked. Ispent the next several days soul-searching, trying to find out something missing in my experimentsand in my thought. I thought day and night.
I often took a rowboat out to the middle of the bay toavoid interference by people. One afternoon, an idea suddenly struck me on the boat. It was a verysimple idea: “Luminescence reaction probably involves a protein. If so, luminescence might bereversibly inhibited at a certain pH.”221b) Although GFP is highly visible and easily crystallizable, the yield of GFP from the jellyfish wasextremely low, much lower than that of aequorin. Therefore, to study GFP, we had to accumulateGFP little by little for many years while we studied the chemistry of aequorin luminescence. Theamount of GFP we accumulated reached a sufficient amount to study this protein in 1979.
Thus, wetried to find out the nature of the GFP chromophore by a series of experiments, using 100 mg of theprotein in one experiment222.c) To this day, we really don’t have a well-accepted explanation as to why the jellyfish wants toglow, why should it show this remarkable phenomenon, when the water is disturbed; nor do weknow why, when the jellyfish glows, why was it so important that it glows green instead of blue.Why not just leave the aequorin, or if it really was important to glow green, why not just changeaequorin in the first place to make it glow green directly rather than invent an additional protein; butwe are very grateful to the jellyfish for having invented GFP223.г) Упражнения, целью которых является осуществление операции обобщения:Ex. 22.
Read the extracts from the article, find key phrases and compress the following extractsof the text.a) Douglas Prasher was the first person to realize the potential of GFP as a tracer molecule. In 1987,he got the idea that sparked the GFP revolution. He thought that GFP from a jellyfish could be usedto report when a protein was being made in a cell. Proteins are extremely small and cannot be seen,even under an electron microscope. However, if one could somehow link GFP to a specific protein,for example hemoglobin, one would be able to see the green fluorescence of the GFP that is attachedto the hemoglobin. Hemoglobin carries the oxygen in our blood.
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