研究:大肠杆菌是如何摄取糖分的?-凯发k8官网

研究:大肠杆菌是如何摄取糖分的?
文章来源:未知 文章作者:meng 发布时间:2009-11-13 03:21 字体: [ ] 
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scientists at the university of york have discovered how certain bacteria(细菌) such as escherichia coli(大肠杆菌) have evolved to capture rare sugars from their environment giving them an 1 advantage in naturally competitive environments like the human 2(肠,勇气). microbes are well-known for their ability to grow in demanding and nutritionally poor environments, which has allowed them to colonise(开拓殖民地) some of the most remote places on the planet. bacteria living in theoretically 3-rich environments like the mammalian(哺乳动物的) 4(肠) face similar challenges due to intense competition between 5 species in the intestine for the finite amount of available food.

researchers led by dr gavin thomas in the university's department of biology discovered that a protein present in the 6 7 escherichia coli was a unique sugar transporter.

common sugars like 8(葡萄糖) form a cyclic structure called a 'pyranose(吡喃糖)' when dissolved in water. all transporters for glucose recognise the pyranose form. but, for sugars such as galactose(半乳糖), which is commonly found in dairy produce, around 10 per cent is found in a different ring form called a 'furanose(呋喃糖)'.

initial work on the unknown e. coli transporter by dr thomas's team suggested that it was a galactose transporter. the researchers knew that e. coli has a galactopyranose(吡喃半乳糖) transporter already, so why should the bacterium have evolved another system to do exactly the same thing?

the answer to the problem was discovered when researchers led by professor keith wilson in the york 9 biology laboratory solved the 3d structure of the protein, revealing that it was bound to the rarer furanose form of galactose. experiments by dr. jennifer potts in the university's centre for magnetic 10 confirmed that the transporter was the first biological example to recognise furanose over pyranose forms.

dr thomas said: "the picture that emerges is that bacteria have evolved many related transporters to allow them to exploit every possible potential source of nutrient in their environment. being able to use the extra 10 per cent of galactose available in the gut appears a trivial adaptation. but it is exactly the small change required to allow e. coli to grow a little bit faster when galactose is present in the gut, and so persist at the expense of other species of bacteria."



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1 ctqz7m     
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。
2 mezzp     
n.[pl.]胆量;内脏;adj.本能的;vt.取出内脏
参考例句:
  • it is not always necessary to gut the fish prior to freezing.冷冻鱼之前并不总是需要先把内脏掏空。
  • my immediate gut feeling was to refuse.我本能的直接反应是拒绝。
3 3vpye     
adj.营养的,滋养的;n.营养物,营养品
参考例句:
  • magnesium is the nutrient element in plant growth.镁是植物生长的营养要素。
  • the roots transmit moisture and nutrient to the trunk and branches.根将水分和养料输送到干和枝。
4 rbpzy     
adj.内部的;国内的;n.肠
参考例句:
  • this vitamin is absorbed through the walls of the small intestine.这种维生素通过小肠壁被吸收。
  • the service productivity is the function,including external efficiency,intestine efficiency and capacity efficiency.服务业的生产率是一个包含有外部效率、内部效率和能力效率的函数。
5 dy5z8q     
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 dbhzx     
adj.肠的;肠壁;肠道细菌
参考例句:
  • a few other conditions are in high intestinal obstruction. 其它少数情况是高位肠梗阻。 来自辞典例句
  • this complication has occasionally occurred following the use of intestinal antiseptics. 这种并发症偶而发生在使用肠道抗菌剂上。 来自辞典例句
7 bn7ze     
n.(pl.)bacteria 细菌
参考例句:
  • the bacterium possibly goes in the human body by the mouth.细菌可能通过口进入人体。
  • a bacterium is identified as the cause for his duodenal ulcer.一种细菌被断定为造成他十二指肠溃疡的根源。
8 fyiyz     
n.葡萄糖
参考例句:
  • i gave him an extra dose of glucose to pep him up.我给他多注射了一剂葡萄糖以增强他的活力。
  • the doctor injected glucose into his patient's veins.医生将葡萄糖注入病人的静脉。
9 itxw5     
adj.构造的,组织的,建筑(用)的
参考例句:
  • the storm caused no structural damage.风暴没有造成建筑结构方面的破坏。
  • the north american continent is made up of three great structural entities.北美大陆是由三个构造单元组成的。
10 hbazc     
n.洪亮;共鸣;共振
参考例句:
  • playing the piano sets up resonance in those glass ornaments.一弹钢琴那些玻璃饰物就会产生共振。
  • the areas under the two resonance envelopes are unequal.两个共振峰下面的面积是不相等的。
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