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
52
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."
Which of the following titles best summarizes the main idea of this passage?
选项
A、Unique Tumor Tissues
B、Limitations of Conventional Cancer Treatments
C、Tumor-killing Bacteria
D、How Do Bacteria Identify Cancer Cells
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/FmSO777K
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
Whensheopenedthedoor,shesawthatnobodyisintheapartmentsinceshe’dleftit.
Americanscertainlyuselotsofenergy,butlessprodigiouslythantheyoncedid.In1985theirconsumptionwasroughlythesame
ScienceWithoutBordersScienceandtechnologyisamongthefactorsthathavetakenthehumancivilizationtotheleveliten
"Historydoesn’trepeatitself,"arguedMarkTwain,"butitdoesrhyme."Inthisinstance,history’sechocouldscarcelybemo
Ofalltheareasoflearningthemostimportantisthedevelopmentofattitudes.Emotionalreactionsaswellaslogicalthought
InterpretthefollowingpassagesfromChineseintoEnglish.Startinterpretingatthesignalandstopatthesignal.Youmaytak
A、Solarenergy.B、Fossilfuels.C、Newnuclearplants.D、Nonuclearplants.C根据原文第二段,核问题涉及能源安全和气候变化的问题。前者反对关闭核电站,并且支持开新型核电站,因为废除核
A、Lowdomesticdemand.B、Highenergycost.C、Deflation.D、WeakereconomicgrowthintheU.S.andChina.B根据原文第一段最后一句“...Japan’s
A、Theorangejuicecanhelptreatindigestion.B、Theorangeinasupermarketismuchcheaper.C、Theorangeismorenutritiousth
TheClassicalSenseofGoodGovernmentPoliticsplaysanextremelyimportantroleinhumansociety.Politicalphilosophersst
随机试题
生地、麦冬、玄参同用的方剂是
设A是三阶矩阵,其三个特征值分别为-1/2,1/2,1,则|4A*+3E|=________.
在基带传输系统中,()的作用是接收信号并尽可能地滤除信道噪声和其他干扰。
膜性肾小球肾炎电镜下的特征性病变是
大骨节病是由哪国人最先报道的
在民事执行中,被执行人朱某申请暂缓执行,提出由吴某以自有房屋为其提供担保,申请执行人刘某同意。法院作出暂缓执行裁定,期限为六个月。对于暂缓执行期限届满后朱某仍不履行义务的情形,下列哪一选项是正确的?()
饮酒后驾驶营运机动车的,处暂扣三个月机动车驾驶证,并处( )罚款。
(1)地方政府及其职能部门利用其行政职权对外地商家进入本地市场、本地企业及资本流出加以限制或歧视,就构成了地方保护主义,其_____是滥用行政职权限制市场竞争,获取地方利益。(2)有人认为,要保持经济霸主的地位,强国就必须______任何潜在竞争对手的发
在一个除法算式里,被除数、除数、商河余数之和是319,已知商是21,余数是6,问被除数是多少?
在窗体中有一个标签Lbl和一个命令按钮Command1,事件代码如下:OptionCompareDatabaseDimaAsString*10PrivateSubCommand1_Click()a="
最新回复
(
0
)