土壤细菌与治病细菌共同进化出抗药基因-凯发k8官网

土壤细菌与治病细菌共同进化出抗药基因

文章来源：未知文章作者：enread 发布时间：2012-08-31 06:23 字体： [ ]　

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soil bacteria and bacteria that cause human diseases have recently ¹ at least seven antibiotic-resistance ², researchers at washington university school of medicine in st. louis report aug. 31 in science. according to the scientists, more studies are needed to determine how widespread this sharing is and to what extent it makes disease-causing pathogens harder to control.

"it is commonplace（平凡的） for ³ to make their way into the environment," says first author kevin forsberg, a graduate student. "our results suggest that this may enhance drug resistance in soil bacteria in ways that could one day be shared with bacteria that cause human disease."

among the questions still to be answered: did the genes pass from soil bacteria to human pathogens or ⁴ versa（反之亦然）? and are the genes just the tip of a vast reservoir of shared resistance? or did some combination of luck and a new technique for studying genes across entire ⁵ communities lead the scientists to discover the shared resistance genes?

humans only mix their genes when they produce offspring, but bacteria regularly exchange genes throughout their lifecycles. this ability is an important contributor to the rapid pace of bacterial evolution. when a bacterial strain develops a new way to beat antibiotics, it can share the strategy not only with its descendants but also with other bacteria.

earlier studies by other scientists have identified numerous resistance genes in strains of soil bacteria. however, unlike the seven genes described in this report, the earlier genes were dissimilar to their analogs in disease-causing bacteria, implying that they had crossed between the bacterial communities a long time ago.

most of the antibiotics used to fight illness today originated from the soil. bacteria use the antibiotics, in part, as weapons to compete with each other for resources and survival. scientists have long acknowledged that gives environmental bacteria an ⁶ ⁷ to find ways to beat antibiotics.

"we wanted to try to get a broader sense of how often and extensively antibiotic-resistance genes are shared between environmental bacteria and pathogens," says senior author gautam dantas, phd, assistant professor of pathology and immunology.

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收听单词发音

1
交换（工作）( swap的过去式和过去分词 )；用…替换，把…换成，掉换（过来）
参考例句：
i liked her coat and she liked mine, so we swapped. 我喜欢她的外套，她喜欢我的外套，于是我们就交换了。 at half-time the manager swapped some of the players around. 经理在半场时把几名队员换下了场。

2
n.基因( gene的名词复数 )
参考例句：
you have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。来自《简明英汉词典》 differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。来自英汉非文学 - 生命科学 - 生物技术的世纪

3
n.（用作复数）抗生素；（用作单数）抗生物质的研究；抗生素，抗菌素( antibiotic的名词复数 )
参考例句：
the discovery of antibiotics in the 20th century 20世纪抗生素的发现 the doctor gave me a prescription for antibiotics. 医生给我开了抗生素。

4
n.坏事；恶习；[pl.]台钳，老虎钳；adj.副的
参考例句：
he guarded himself against vice.他避免染上坏习惯。 they are sunk in the depth of vice.他们堕入了罪恶的深渊。

5
a.细菌的
参考例句：
bacterial reproduction is accelerated in weightless space. 在失重的空间，细菌繁殖加快了。 brain lesions can be caused by bacterial infections. 大脑损伤可能由细菌感染引起。

6
adj.进化的；演化的，演变的；[生]进化论的
参考例句：
life has its own evolutionary process.生命有其自身的进化过程。 these are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

7
n.刺激；动力；鼓励；诱因；动机
参考例句：
money is still a major incentive in most occupations.在许多职业中，钱仍是主要的鼓励因素。 he hasn't much incentive to work hard.他没有努力工作的动机。