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New tool to help protect animals from harmful hues of light
Date:
June 12, 2018
Source:
University of Southern California
Summary:
A research team identifies harmful effects to wildlife as LED lights proliferate. Some hues, including blues and whites, imperil creatures while other wavelengths are more benign. They devised an interactive web-based tool to help people make wildlife-friendly choices in outdoor lighting.
A new generation of outdoor lights spreading across landscapes require greater scrutiny to reduce harm to wildlife, says a USC-led research group that developed a new tool to help fix the problem.
The team of biologists surveyed select species around the world to determine how the hues of modern light-emitting diode (LED) lamps affect wildlife. They found that blues and whites are worst while yellow, amber and green are more benign. Some creatures, including sea turtles and insects, are especially vulnerable.
The findings, which include the first publicly available database to help developers, designers, and policymakers choose wildlife-friendly lighting colors, appear today in the Journal of Experimental Zoology Part A: Ecological and Integrative Physiology.
“Outdoor environments are changing rapidly and in ways that can impact wildlife species,” said Travis Longcore, lead author of the study and assistant professor of architecture, spatial sciences and biological sciences with the Spatial Sciences Institute at the USC Dornsife College of Letters, Arts and Sciences. “We provide a method to assess the probable consequences of new light sources to keep up with the changing technology.”
Big cities and industrial sites so illuminate night sky now that much of Earth resembles a big, glowing ball. Scientists have spent years studying how light brightness and direction affects wildlife, including migration and attraction, predator-prey relationships and circadian rhythms. The USC team availed that existing ecological data and broke new ground by examining how a range of commercially available LED lights impact species.
LED lights are expected to comprise 69 percent of the global market by 2020, compared to just 9 percent in 2011. They are popular because they have many uses, conserve energy and last longer than other lamps.
To understand the impacts, and find compromise solutions between human and animal needs, the researchers focused on insects, sea turtles, salmon and Newell’s shearwater, a seabird, for which existing data were readily available. They found that the worst nighttime lights are intense blue and white colors—some affect species as much as the brightness of midday sun—and three times more than yellow or green lights designed with wavelengths less disruptive to wildlife.
The research is important for wildlife conservation. For example, loggerhead sea turtle hatchlings, an endangered species, leave beach nests at night and follow artificial light inland to danger instead of skittering to the ocean. Similarly, lights attract migrating juvenile salmon, exposing them to predators. Also, global declines in insects have been linked in part to light pollution, Longcore said. The new research will help people choose lighting to reduce wildlife impacts.
The researchers focused on only four groups of creatures, which have been studied for light responses previously. Future studies will incorporate more species worldwide.
A central component of the USC research includes the first publicly available database showing how about two dozen different types of artificial lighting affect wildlife. The matrix is called “Rapid Assessment of Lamp Spectrum to Quantify Ecological Effects of Light at Night.” Developers, land-use planners and policy makers can use it to choose lighting that balances the needs of nature and people. Today, regulations to limit light direction or intensity typically don’t account for the different hues of LED lights, Longcore said.
“If we don’t provide advice and information to decisionmakers, they will go with the cheapest lighting or lighting that serves only one interest and does not balance other interests,” Longcore said. “We provide a method to assess the probable consequences of new light sources to keep up with the changing technology and wildlife concerns.”
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Putting animals in their best light: Some shades of LED lamps threaten wildlife, tasks.
Task1. Find words/expressions meaning the following.
1. to put something in danger;
2. study;
3. shades;
4. easily harmed or hurt;
5. to influence; (2)
6. to move at the same speed;
7. to consist of;
8. that can be found or obtained;
9. causing problems and preventing something from continuing in its normal way;
10. fall;
11. explain , justify
Task2. Say if the following is true, false or not mentioned.
1. All LED lights irrespective of their spectra are equally harmful for animals.
2. Some animals can be affected more than others.
3. It is only recently that scientists have got interested in the effect of artificial light , its intensity and direction on animals e.g. migration and attraction, predator-prey relationships and circadian rhythms.
4. Artificial light can cause migrating birds to wander off course and toward the dangerous nighttime landscapes of cities.
5. Since 2011 the share of LED lights have increased by 60 per cent.
6. Artificial lights draw turtles away from the ocean. In Florida alone, millions of hatchlings die this way every year.
7. Intense blue and white colors are the most harmful as they affect animals as much as the midday sun.
8. The scientists concentrated on four groups of animals as they were the easiest to study.
9. This study can be used to find equilibrium between the interests of people and those of animals
Task3. Answer the following questions .
1. Why should LED lights studied more carefully?
2. What spectra affect animals worst?
3. What creatures suffer most?
4. How can the situation be changed?
5. What are the examples of a hazardous effect LED lights have on animals?
6. Why were only four groups of animals studied?
7. What is the research based on?
8. How should its results be used?
Genetics. Evolution
The CRISPR Antidote
Scientists hacked the machinery of cellular warfare to splice genes. Now they’ve found a way to guard against it, too.
By Eric Betz| Friday, November 10, 2017
An arms race is playing out inside your body. It’s part of an invisible war that’s raged for billions of years. When viruses hunt and infect bacteria, the bacterial survivors store pieces of their vanquished foes — DNA snippets — within their genomes so that next time, they can detect and defend against the attack. In response, viruses evolve their own counterattack.
The bacteria’s natural defense system is called CRISPR-Cas9. And in 2012, biochemist Jennifer Doudna, together with French microbiologist Emmanuelle Charpentier, upended genetics with an ingenious idea. What if scientists could exploit CRISPR as a gene-editing tool? Since then, Doudna and others have hacked these cellular weapons in an effort to treat diseases and create stronger crops. Now scientists are attempting another task: avoiding unintended mutations resulting from their gene edits.
To grasp the tool’s precision, imagine the letters of a genome — G, A, T, C — typed into a stack of books dozens of stories high. A guide RNA shepherds Cas9 — which acts like a pair of DNA scissors — to the right spot, where it zooms in on just 20 letters and lets scientists change a few.
“CRISPR-Cas9 lets you find the right spot,” says Joseph Bondy-Denomy, a microbiologist at the University of California, San Francisco. “That’s a big deal.”
Indeed, a global gene editing revolution is underway. Lawyers battle over patent rights. CRISPR startups are selling stocks on the NASDAQ. And in a milestone this year, Oregon Health and Science University researchers used CRISPR to successfully correct heart disease-causing genes in human embryos. It was the first U.S. CRISPR experiment on humans.
But despite its track record, sometimes CRISPR brings unintended consequences — gene edits in undesired locations. Scientists call these “off-target effects.” Cas9’s scissors don’t always stop once the targeted cuts are made. Sometimes the scissors will roam for another day or two, cutting other sites that resemble the target but aren’t quite a perfect match.
“If left to their own devices, over time, [CRISPR proteins] might have the ability to cause trouble,” says Doudna, who is also a University of California, Berkeley, professor.
In May, a group of ophthalmologists and others sounded the alarm bells in a letter published in Nature Methods. The team used CRISPR to fix a blindness-causing gene in mice. But when they re-examined the mice, they found hundreds of unintended genetic mutations.
Doudna challenges the group’s methods and thinks that, in general, the off-target fear is overblown. Scientists knew about these mutations, and the technology is more than accurate enough for academic research purposes. The problems begin only as scientists move CRISPR into complex clinical trials.
Bondy-Denomy, the UCSF micro-biologist, appears to have found a “natural” way to combat these off-target effects. His research focuses on the arms race between bacteria and viruses, and last year, Bondy-Denomy started testing out a hunch. If bacteria defend against viruses using CRISPR, he reasoned, then viruses likely have a response to counteract it. He was right. Viruses do produce “anti-CRISPR” proteins that grab Cas9 and impair its gene-editing ability. He published his results in Cell in January 2017. “This is basically an off switch,” he says.
By summer, Doudna, Bondy-Denomy and their collaborators had used this viral counterpunch to reduce off-target effects. In Science Advances, the team detailed how they used CRISPR to make edits and then deployed anti-CRISPR to stop the Cas9 scissors from running amok.
The technique could help CRISPR move from the lab toward more therapeutic applications where absolute precision is required, Doudna says. Other teams are exploring different ways to avoid off-target effects, too. For example, the team that edited human embryos earlier this year saw no off-target effects, thanks to prep work aimed at keeping CRISPR on a shorter leash.
However, this gene-editing antidote could have another important use. Security experts, including former Director of National Intelligence James Clapper, worry that CRISPR makes things easier for would-be bioterrorists. Bondy-Denomy says if someone launched a CRISPR attack on humans or our crops, anti-CRISPR could work as an antidote. DARPA, the U.S. military research agency, liked the idea enough to give Doudna and Bondy-Denomy a grant to continue making Cas9 safer.
While Bondy-Denomy doubts CRISPR will ever be deployed in a human battle, he can at least be confident in knowing anti-CRISPR has already proven itself in the cellular arms race.
The CRISPR Antidote, tasks.
Task1. Find the equivalents of the following word combinations in the text.
1. держать на коротком поводке
2. предоставленные сами себе
3. по-видимому нашли
4. выйти из-под контроля
Task2. Find words/expressions meaning the following.
1. that cannot be seen;
2. enemy;
3. to understand;
4. the quality, condition, or fact of being exact and accurate ;
5. having started and in progress
6. the results or effects of something;
7. . a small cutting tool with two sharp blades that are screwed together;
8. to look like;
9. to question the truth, value of ideas;
10. to get out of control
Task3 Say if the following is true, false or not mentioned.
1. The bacteria that are not killed by viruses make pieces of the viruses’ DNA a part of their genome, which helps them survive another attack.
2. A French scientist came up with the idea of using the bacteria natural defence system to make changes in genes.
3. He suggested using CRISPR-Cas9 to combine genes of different species creating chimeras.
4. American researchers used CRISPR to successfully correct heart disease-causing genes in people addressing their heart problems and making heart surgery unneccasary.
5. If they are not taken care of, after a while CRISPR proteins normally mutate and cause cancer.
6. A California University scientist is of the opinion that the off-target danger is exaggerated.
7. To solve the problem scientists decided to use other bacteria with different CRISPR proteins.
8. CRISPR may prove handy for criminals.
9. The only remedy in the situation is to make people and crops immune to CRISPR proteins.
Task4. Answer the following questions.
1. What arms race does the author mean?
2. How can the bacteria natural defence system be used?
3. What difficult problem do scientists face?
4. What is the way out?
5. Has this method been put to practice? Why? Why not?
6. Why is the technique so important?
7. What are the other uses of the antidote?
Дата: 2019-02-02, просмотров: 222.