题目

Directions: Read the passage carefully. Fill in each blank with a proper sentence given in the box. Each sentence can be used only once. Note that there are two more sentences than you need. A. With this modified method, we show variation in honey bee immunity in response to different classes of pathogens. B. Together, they collected about 150 nurse bees and divided them among six queenless mini hives equipped with broods of larvae to look after. C. Indeed, they actually possess fewer immune-related genes than most solitary bees. D. Over the years, scientists have uncovered how insect immunity relates to behavior, mating success, ability to find food, nutrition, energy cost, etc. E. These act as antigens which trigger the development of a protective immune response in the developing young. F. But it may still come as a surprise that human beings are not alone in having invented vaccination. Swarm Immunity Honeybees run vaccination programmes, too. An old saw has it that there is nothing new under the sun. Work just published in the Journal of Experimental Biology by Gyan Harwood of the University of Illinois, Urbana-Champaign, confirms that honeybees got there first. It also suggest that they run what look like the equivalent of prime-boost childhood vaccination programmes. Being gregarious, honeybees are at constant risk of diseases sweeping through their hives. Most animals which live in crowded conditions have particularly robust immune systems, so it long puzzled entomologists that honeybees do not. Part of the answer, discovered in 2015, is that queen bees vaccinate their eggs by transferring into them, before they are laid, fragments of proteins from disease-causing pathogens. But that observation raise the question of how the queen receives her antigen supply in the first place, for she subsists purely on royal jelly, a substance secreted by worked bees which are at the stage of their lives (which precedes the period that they spend flying around foraging for nectar and pollen) when they act as nurses to larvae. Dr Harwood therefore wondered if the nurses were incorporating into the royal jelly they were producing, fragments from pathogens they had consumed while eating the victuals brought to the hive by the foragers. To test this idea, he teamed up with a group at the University of Helsinki, in Finland, led by Heli Salmela. Instead of nectar, they fed the nurses on sugar-water, and for these of the hives they laced this syrup with Paenibacillus larvae, a bacterium that causes a hive-killing disease called American foulbrood. 答案：【1】F【2】C【3】E【4】B

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