Pаrt V: Sentence cоmpletiоn: Use cоrrect verb tenses аnd punctuаtion. NOTE: Write the complete sentence in your response. Use Ctrl and C to copy, and use Ctrl and V to paste. Yesterday, while the teacher
DIRECTIONS: Reаd the pаssаge and answer the questiоns. Hypоallergenic 1 Cats A The wоrld's first hypoallergenic cats may soon be curling up and purring in the laps of allergy sufferers. Allerca, Inc., a biotechnology firm in San Diego, California, is now taking orders for its Allerca Gene Divergence (GD) kittens. The cats are not transgenic animals—which means their genes have not been altered to make them less of an allergy risk. Instead Allerca officials say they searched for natural genes in the cat that control these allergy-inducing properties and then bred cats with the desired trait. B "People breed cats all the time, so why not a company who has used data based on experiments to identify hypoallergenic cats? Siberian cats have been touted by breeders as being hypoallergenic for a long time" said Leslie Lyons, an assistant professor in the school of veterinary medicine at the University of California, Davis. According to Lyons, who specializes in research on domestic cat genetics, if Allerca used Siberians—or another low-allergen breed found through genetic screening—a hypoallergenic breed could be developed in as few as "one to two crosses." C Megan Young, Allerca's CEO, said that the firm has simply "taken selective breeding to the next level." Allerca officials are closely guarding their scientific data. But Young says human-exposure trials conducted by Allerca and an independent lab revealed that known cat-allergy sufferers ranging from mildly to highly allergic showed no signs of reaction when in contact with the newly bred cats. She also notes that Allerca plans to submit its findings for publication in a peer-reviewed journal in early 2007. D Approximately 10 million people in the U.S. are allergic to cats, according to the nonprofit Asthma and Allergy Foundation of America. Cat allergens can trigger severe asthma attacks for 20 to 30 percent of asthma sufferers and exposure can lead to chronic asthma. E Contrary to popular belief, people are not allergic to a cat's fur or dander. The sneezing, wheezing, and itching are brought on by Fel d 1, a protein excreted in feline saliva and skin glands. Even a hairless breed can trigger an allergic reaction. Cats—notorious self-groomers—transfer the allergy-inducing protein to their skin and fur while licking themselves. F According to Young, Allerca researchers used genetic sequencing to search for natural variations in the genetic code of the Fel d 1 protein. They then selectively bred cats to express the protein at a lower molecular weight, reducing the likelihood of an allergic reaction. G Allerca's low-allergen felines, expected to arrive in homes next spring, carry a price tag that could send some pet lovers into shock. The firm currently charges $3,950 (U.S.) per cat, plus nearly $1,000 for processing and transportation. The steep cost includes pet insurance, vaccines, a microchip identifier, spaying or neutering, nail caps, and a starter kit. Kittens will be delivered via private jet courier to pre-selected veterinary offices where owners can pick them up. H Because building up a breeding pool takes time, Young projects that Allerca will only have 400 to 500 cats available next year. As a safety precaution, Young says the kittens will be tested for their Fel d 1 levels before they are delivered. Owners and their homes must also undergo FDA-approved allergy tests to create a baseline for any preexisting allergens. Should an individual exceed the threshold level for tolerating the new cats' low levels of allergens, Allerca will strongly suggest the owner not claim the cat and will refund the purchase price. Cat Fight?I A Denver, Colorado-based firm, Felix Pets, is trying to produce hypoallergenic cats using a different technique: developing a hypoallergenic cat via direct cellular modification. In theory, while a developing kitten is still a single cell, its DNA can be modified to remove or suppress the gene that produces the allergen protein, Felix Pets' president David Avner explains. The modified cell would then be implanted into a surrogate mother cat to finish developing into an allergen-free kitten. Avner says gene modification has an advantage over selective breeding in that modification takes less time to produce a cat consistently free of the allergen protein. "To breed out the allergen could take decades," he said. Avner says he expects to have transgenic allergen-free cats ready for the market by 2008. While kittens will be "expensive" initially, Avner said, he hopes to eventually sell them for $800 to $1,000. J According to Young, Allerca had been pursuing genetic modification until last year, when researchers ran into challenges silencing the allergen-producing gene. But it was during this research that Allerca developed genetic testing to focus on less potent versions of the Fel d 1 protein. Little is known about the exact role the Fel d 1 protein plays in cats, so no one is sure what effect removing or suppressing the protein would have on an animal. UC Davis' Lyons, agrees: "If [we learn] anything from these experiments these companies are doing, we might learn a lot about the physiology of this particular protein." 1 If something is hypoallegenic, it is less likely to cause an allergic reaction. Source: Adapted from “‘Hypoallergenic’ Cats for Sale, U.S. Firm Announces,” by Rachel Pepling: National Geographic News: June 2006 Choose the correct answer.What are transgenic animals?
DIRECTIONS: Reаd the pаssаge and answer the questiоns. The War оn Allergies A Suppоse that 54.3 percent of your country’s population had cancer. That figure might set off a nationwide panic—a search for something wrong with people’s diet, the environment, activity levels. In fact, that’s the percentage of Americans who show a positive skin response to one or more allergens. B The manifestations of allergy—sneezing, itching, rashes—are signs of an immune system running amok, attacking foreign invaders—allergens— that mean no harm. Allergens include pollen, dust mites, mold, food, drugs, stinging insects, or any other substance to which the body can choose to react, or overreact. Allergies rarely kill. They just make the sufferer miserable—sometimes for brief periods, and sometimes for life. C Allergies are essentially an epidemic of modernity. As countries become more industrialized, the percentage of population affected by them tends to grow higher. There are remote areas of South America and Africa where allergies are virtually nonexistent. D In contrast, six percent of young children in the U.S. today have food allergies. Federal legislation requires manufacturers to clearly label whether major allergens—peanuts, soy, shellfish, eggs, wheat, milk, fish, and tree nuts—are ingredients in any product. Children who cannot tolerate these foods sit at special tables at lunchtime; there are websites and support groups for parents who homeschool their severely allergic children. E Here’s how an allergy develops: One day, a body is exposed to a protein in something that seems perfectly harmless—the wheat flour, say, in a home-baked muffin. But for some unclear reason, the body looks at the protein and sees trouble. There will be no symptoms at first, but the body is remembering—and planning. F That first exposure causes the immune system to produce an antibody called IgE (immunoglobulin E). Then IgE antibodies attach to certain cells, called mast cells, in tissue throughout the body. There they stay like wary soldiers waiting for war. With a second exposure, even months later, some of the allergen binds with the IgE on the mast cell. This time, the mast cell releases a flood of irritating chemicals, which cause inflammation and itching. G A minor or isolated reaction can become more serious with repeated exposure to an allergen, or when other cells involved in the immune system, the T cells, come into play. Certain T cells remember the “insult” of the allergen and ensure that some part of the body keeps becoming inflamed. Often the allergen and the immune system become increasingly antagonistic, and the reaction worsens. H There is, unquestionably, a hereditary component to allergies. In some cases, people with allergies show signs of asthma. A child with one asthmatic parent has a good chance of developing the condition. If both parents have asthma, the chance of occurrence increases. I Still, the rise in allergies is too rapid to be explained solely by genetics. “The genetic pool can’t change that much in such a short time,” says Donald Leung, director of an allergy-immunology program in the U.S. “There have to be environmental and behavioral factors as well.” Dozens of theories have blamed everyone from urban landscapers for favoring male plants (the ones that produce pollen), to women who don’t breastfeed. Breastfeeding, the theory goes, confers greater protection against allergies. J Another probable factor: diet. “Reduced fresh fruit and vegetable intake, more processed food, fewer antioxidants, and low intake of some minerals—these are all shown to be a risk,” says professor of medicine Harold Nelson, considered one of the foremost experts on allergies in the U.S. K The use of antibiotics may also be an underlying cause of rising allergy rates. Certain bacteria in the intestine are associated with greater or lesser chances of having allergies. Researchers believe, as Donald Leung says, “Overuse of antibiotics may be disrupting certain gut flora that suppress allergy.” L Another prime culprit: environmental pollutants. Exactly what pollutants and in what quantities are a source of heated debate. One of dozens of examples: Children who are raised near major highways and are exposed to diesel fumes from trucks register an increased sensitivity to allergens they already react to. M Ironically, it’s not just the pollutants that are affecting us. It may be too much cleanliness. A prevalent theory among allergists is known as the hygiene hypothesis. While it’s true that industrialization brings with it better health care and fewer serious childhood infections, it also brings an obsession with cleanliness. We are not exposed to dirt at a young enough age to give our immune systems a good workout. Also, because of the high cost of energy, more homes are built with better insulation—insulation that seals in mold and dust. N “The hygiene hypothesis has been on the scene since people first started looking at allergies,” says associate professor Andrew Liu. “John Bostock, the guy who first identified hay fever in 1819, noted that it was a condition of the educated. He couldn’t report any cases among poor people.” O But if dirt is a good thing, why are allergies and asthma so prevalent today in poor, inner-city neighborhoods? “It’s not just a question of exposure to dirt that reduces allergies—it has to be the right kind of dirt,” says Liu. “We’re talking about exposure to endotoxin and good microbes in soil and animal waste.” Research supports the hygiene hypothesis. “There was a famous study,” says Harold Nelson, “where one of the protective factors for asthma was having a pig in the house.” P Since most of us are unable to room with a pig, we have to come up with a plan. Can we avoid allergies altogether? Can we get rid of allergies we already have? Can we desensitize our immune systems? “We still don’t know exactly how to prevent allergies,” says Andrew Liu. “We know the immune response is supposed to be a helpful one, that it’s not supposed to be the cause of disease. We know that the immune system of someone with allergies needs to be reeducated. But how? It’s not always clear.” Leung agrees, adding, “If you are exposed to . . . microbial products early in life, it may prevent allergies. But later in life, the early exposure may actually make things worse.” Q There are those who argue that to prevent allergies, we should reduce exposure to harmful allergens early on. Others believe allergens should be administered in large quantities at a young age. Many believe it depends on the specific allergen. And food allergies may work on an altogether different principle. Confused? So are the allergists. R But there is hope that allergy sufferers may one day live in a world that’s far more comfortable. Suddenly there’s a booming market for products and services that were unimaginable 30 years ago. Hotels offer allergy sufferers rooms with special ventilation systems and linens washed with nontoxic products. Scientists are finding ways to get rid of the allergenic proteins in common offenders. Researchers at the University of Melbourne in Australia also claim to have developed the first hypoallergenic rye grass: It doesn’t cause hay fever. S But the questions remain: Are allergies truly preventable? How much genetic engineering is feasible? And even if we can eliminate the allergens we fight today, what will our immune systems decide are the enemies tomorrow? Choose the best answer.The hygiene hypothesis ____________________.
DIRECTIONS: Chооse the cоrrect word from the box to complete eаch sentence. Use eаch word only once. component confers culprit federаl legislation miserable register set off suppress tolerate As people become more aware of the effects of electronic cigarettes, _______________ will control their sale and use. [BLANK-1]