首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Imagine a bacterium that, when injected into the bloodstream, would travel to the site of a tumor, insert itself into the cancer
Imagine a bacterium that, when injected into the bloodstream, would travel to the site of a tumor, insert itself into the cancer
admin
2018-06-06
83
问题
Imagine a bacterium that, when injected into the bloodstream, would travel to the site of a tumor, insert itself into the cancer cell, and then produce a cancer-killing compound. That’s exactly what scientists at the University of California, Berkeley(UCB)and University of California, San Francisco(UCSF)have set out to do.
Traditional cancer therapies are limited for two key reasons: little of the drug actually reaches the tumor and the drug is toxic to both cancerous and healthy tissues. Bacteria, however, have the potential to precisely target cells. "In a way, bacteria are the ultimate in smart drugs," says George Church, a geneticist at Harvard Medical School in Boston(he was not involved in the current work, but will collaborate on the project in the future). "It’s hard to pack a lot of intelligence into a small molecule or protein: but bacteria can have sensors and actuators and can drill into a cell, like a submarine."
To build a cancer-killing bacterium, biologists must create organisms that can perform a series of complicated functions—namely, when in the bloodstream, they have to sense and respond to the tumor environment. Once inside the tumor, the bacteria must infiltrate the cancer cell, and then—and only then—start producing a tumor-killing toxin. The researchers plan to engineer such super-organisms by co-opting parts from different types of bacteria and inserting them into Escherichia coli, a bacterium commonly used in research.
Tumor tissue has unique characteristics, including lower oxygen and higher lactic acid concentrations than surrounding tissue. To create a bacterium that can sense a tumor, Christopher Anderson, a postdoctoral researcher at UCB and UCSF, and colleagues took an oxygen sensor from E. coli and linked it to a special protein, called invasin, from another type of bacteria, which allows the organism to invade cancer cells. In a paper published earlier this year in the Journal of Molecular Biology, the researchers showed in a test tube that the engineered bacterium selectively invades tumor cells.
Anderson and colleagues are now working on making the system even more specific. To ensure that the bacteria invade only tumor cells, they will create a genetic mechanism that allows the invasin protein to be expressed only when two conditions are met, such as when both the oxygen and lactic acid concentrations are at a certain level. Essentially, it’s a genetic version of what’s known in engineering terms as an AND gate—a regulatory circuit that’s turned on only if two conditions are met.
"By using multiple cues, we can garner a great deal of specificity," says Adam Arkin, a bioengineer at UCB and the Lawrence Berkeley National Laboratory, a TR100 recipient in 1999, and one of the senior scientists on the project. "After the bacteria sense the cues, they turn on the rest of the apparatus to do the job."
According to the passage, which of the following statements is NOT true?
选项
A、A genetic mechanism should be designed to make sure that the invasin protein is released only when two conditions are met.
B、Tumor tissue has lower oxygen and higher lactic acid concentrations than surrounding tissue.
C、Research has shown that bacterium loaded with intelligence selectively invades tumor cells.
D、In terms of targeting cancerous tissues, bacteria is inferior to commonly applied cancer treatment.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/UmSO777K
本试题收录于:
NAETI中级口译笔试题库外语翻译证书(NAETI)分类
0
NAETI中级口译笔试
外语翻译证书(NAETI)
相关试题推荐
DemonstratorsrallyatLosAngelesCityHallduringthefirstWomen’sMarch,heldonJan.21,2017,onedayafterPresidentTrum
CitingOhioordinancesthatallowindividualstoseekchargesagainstsomeonethey’veseencommitacrime,sevenEuclidresident
"Historydoesn’trepeatitself,"arguedMarkTwain,"butitdoesrhyme."Inthisinstance,history’sechocouldscarcelybemo
OnethirdoftheChineseintheUnitedStatesliveinCalifornia,mostlyintheSanFranciscoarea.
Socialcontrolreferstosocialprocesses,plannedorunplanned,bywhichpeoplearetaught,persuaded,orforcedtoconformto
Allthesecrashesresultfrom________driving—simplynotpayingattentiontotheroadwhenthedriversaredriving.
A、2million.B、5%.C、2.5%.D、Halfamillion.D原文关于跨种族通婚的数据颇多,根据题干内容可确定原文第一段最后一句中“...almosthalfamillionofthemarebetweenbl
A、Mother-to-childtransmission.B、Bloodtransfusions.C、Patient-to-healthcareworkers.D、Drugabuser.D
由于精神病医生的缺乏及对于心理疾病存在社会偏见,在我国现有的3000万抑郁症患者中,仅有10%的人在接受正规治疗。
A、Theyarecheaper.B、Theydonotpolluteasmuch.C、Theyaresimplertodrive.D、Theyarefaster.B
随机试题
心尖在胸前壁的体表投影()。
消费者权益保护方面的知识,叙述最准确的是()。
相邻关系与地役权的区别包括()。
一般说来,有利于解决问题的动机强度是()。
学前儿童自我意识真正形成的标志是()
2013年上半年,浙江省规模以上工业企业营业收入和利润总额分别为28544.6和1380.2亿元,同比分别增长8.1%和13.0%,增幅比上年同期分别回升0.6个和3.4个百分点;企业亏损面和亏损率分别为20%和12.7%,增幅比上年同期分别回落5.2个和
鸡油菌是一种野生蘑菇,生长在能为它提供所需糖分的寄生树木,例如道格拉斯冷杉下面。反过来,鸡油菌在地下的根茎细丝可以分解这些糖分并为其寄生树木提供养分和水分。正是这种互惠的关系,采割道格拉斯冷杉下面生长的鸡油菌会给这种树木造成严重的伤害。下面哪一个如果是正确
Somepeoplethinkthattheamountoftimeandmoneyspentontheprotectionofwildanimalswouldbebetterspentonimprovingt
Inthedaysbeforepreschoolacademieswereallbutmandatoryforkidsunder5,IstayedhomeandgotmyearlyeducationfromMi
Whendoesthemuseumclose?
最新回复
(
0
)