Pracrise Listening 39 - Thấm Tâm Vy

Nội dung text: Pracrise Listening 39 - Thấm Tâm Vy

1. Exactly how TDCS has this effect on the brain is not clear. The left side of the Neuroscience IFG works according to a more rigid interpretation of the world based on SPARK OF GENIUS concrete features like language comprehension. Inhibiting that under the cathode, while encouraging activity in the more freethinking right-hand side of Stimulating the brain with electricity can improve creativity the IFG with the anode, perhaps helped the students to think outside the box. Paul Mc Cartney famously took the melody for “Yesterday” from a dream, Dr Nissen says most of his team are looking for new ways to help patients with while Thomas Edison argued that his best ideas came from hard work. Others mental disorders, such as breaking patterns of repetitive negative thinking by have looked to coffee, drugs or love. But what if creativity could be turned on encouraging cognitive flexibility. But his study’s insights can be applied to work with a flick of a switch? and jobs outside the lab or clinic. The Alternate Uses Task, for example, assesses Elisabeth Hertenstein at the University of Freiburg, Germany, and her the creative skills required to brainstorm new products or see previously colleagues have done just that, using a technology known as transcranial direct untapped potential in an everyday object. current stimulation (TDCS). Their insights could help creatives to stay at the top of their game. TDCS uses electrodes attached to the scalp to pass a tiny  electrical current through the brain. Neuroscientists think the current makes the Gene editing brain cells underneath the positive electrode (anode) work harder, while the JUMP START negative electrode (cathode) has the opposite effect and calms activity in nearby neurons. In a paper published in Brain Stimulation, the scientists reported that 22 From designer babies to selfish genes, crispr is back in the spotlight minutes of TDCS significantly improved the performance of university students As far as experts are concerned, the technology of gene editing is nowhere near on three standard tests used by psychologists to measure aspects of creativity. ready to be used to create gene-edited babies. This, of course, is separate from The first test is called the Alternate Uses Task and measures conceptual the question of whether it is morally right to do so. Nevertheless, around the expansion: typically by asking people to think of as many possible uses for an world, would-be baby tinkerers have failed to get the memo. This week a everyday object, such as a brick or a paperclip. The second, the Compound Russian scientist announced his ambition to repeat a Chinese scientist’s gene- Remote Associate Task, asks for words that work as common prefixes or suffixes editing experiment on human embryos, which lead to the birth of two babies for unrelated terms. So the answer to “age; mile; sand” is stone. And the third, with modified CCR5 genes last year. The Chinese effort was roundly the Wisconsin Card Sorting Task, has long been used to track how well condemned on grounds of safety and ethics. volunteers can adapt to changing circumstances by getting them to match Moreover, at the start of June evidence emerged that the genetic mutation in the pictures by shape, colour or number of objects, and then changing the rules of gene ccr5, one that offers protection against infection from HIV, is also the game. associated with slightly earlier death. The student volunteers performed the best when the anode was attached above The finding highlights the need to understand far more about how alterations in the right side of their inferior frontal gyrus (IFG)—part of the frontal cortex a cell’s DNA translate into changes in how it functions. There are also a variety and a region associated with problem solving and spontaneity—and the cathode of concerns about the basic technology that need to be dealt with before it can be fitted above the left side of the IFG. The researchers were trying to increase used widely in treatments for the sick—let alone to tinker with healthy activity in the right side and reduce activity in the left. embryonic humans. CRISPR-Cas genome-editing systems, often just known as Christoph Nissen, a member of the research group, says the students given crispr, are molecular machines that can be programmed to home in on specific TDCS performed 10-20% better on the three tasks than those given a sham sections of DNA in the genome and cut both strands of the double helix stimulation, in which the electrodes were put in place but the current was turned molecule. This system allows genes to be knocked out or, in some cases, added. off. And when the electrode positions were reversed, the scientists saw a It is not a perfect mechanism. One concern, for example, is that editing can corresponding decrease in measured creativity compared with the sham group. alter DNA in places it isn’t supposed to and that these “off-target” effects could trigger cancers. A second worry is that the cell can fill gaps with random DNA Thẩm Tâm Vy, June 16th, 2019 PRACTISE LISTENING 39
2. when it is making repairs. These could silence genes that the organism may Dr Zhang and Dr Sternberg have now demonstrated programmable CRISPR- need. A third concern is that although CRISPR successfully hunts down and cuts Cas gene-editing systems that do just this by harnessing a protein encoded by a out faulty DNA, it is harder to get it to insert the right new genes. jumping gene known as Tn7. Dr Sternberg says that instead of making a Firms involved in developing CRISPR editing for use in medicines have double-stranded cut to DNA, and waiting for the cell to repair itself, in the new downplayed concerns. Perhaps that was inevitable as they depend on investors’ system the act of insertion happens at the same time a cut is made. optimism. Rapid advances in many areas have supported the optimists’ case that Because the transposon method of gene editing does not need a cell’s own the gremlins in the new techniques can be overcome in time. “Yesterday’s repair mechanisms to conduct and make good the edit, it offers a mechanism for problems are not necessarily tomorrow’s,” observes Helen O’Neill, a molecular adding genes into a wider variety of cells. This includes neurons and, most geneticist at University College London. critically, cells that are not currently replicating in a suitable way for CRISPR to In that vein come two papers describing a way to improve crispr. The first from work. Although the new papers only demonstrate that jumping-gene editing a team led by Feng Zhang of the Broad Institute in Cambridge, Massachusetts, works in bacteria, scientists have high hopes that it might work in human cells. was published on June 6th, in Science. The second comes this week in Nature The news is welcome in a field where the potential applications in medicine from Samuel Sternberg’s team at Columbia University in New York. seem to grow by the day. Verve Therapeutics, a biotech firm in Cambridge, Selfish genes Massachusetts, recently said that it wanted to use genetic editing to protect Both teams made use of “jumping genes” or transposons (often called selfish patients from coronary heart disease. CRISPR Therapeutics, based in Zug, genes), which are pieces of DNA that seem to hop around genomes with little Switzerland, wants to edit beta cells, which produce insulin, so that they can be more purpose than to proliferate. transplanted into diabetics without rejection. In all these therapies, regulators will have to assess the risks and benefits. That will be easier when small risks of mistakes are set against the benefits of curing a fatal disease. But if CRISPR is to be used more widely and safely, more understanding will be needed of how genetic changes actually relate to differences in how a cell functions. That effort got a boost this week. Jennifer Doudna (pictured) of the University of California, Berkeley, who discovered CRISPR-Cas gene editing and is a leading scientist in the field, will collaborate with GSK, a drugs firm based in London, to elucidate the basic science of gene editing. The new Laboratory for Genomic Research, based in San Francisco, is a $67 million five-year collaboration that may ultimately be useful for drug development and would-be gene editors—whether they seek to make changes to adults or embryos.  [The Economist, UK, June 16, 2019] Notes: - transcranial: xuyên hộp sọ - gyrus: cuộn não Doudna and her team, watching out for jumping genes - cortex: vỏ não - sham (adj.) = false: giả They were thought to do so aimlessly but, in 2017, it was discovered that some - inhibit (v.) kềm chế - roundly condemn: chỉ trích hoàn toàn contained gene-editing systems that were very good at recognising specific DNA - helix molecule: phân tử (AND) xoắn kép sequences. These were able to control where the jumping genes landed. That, in - gremlin: vật gây rối giả tưởng turn, led to the idea, says Dr Sternberg, that it might be possible to harness - transposon: gien ích kỷ jumping genes in gene editing. - elucidate (v.) = clarify: làm sáng tỏ Thẩm Tâm Vy, June 16th, 2019 PRACTISE LISTENING 39