首页
登录
职称英语
Imagine a bacterium that, when injected into the bloodstream, would travel t
Imagine a bacterium that, when injected into the bloodstream, would travel t
游客
2025-01-13
39
管理
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." [br] By quoting "... but bacteria can have sensors and actuators and can drill into a cell, like a submarine"in paragraph 2, the author indicates that______.
选项
A、the shape of bacteria is similar with a submarine
B、it is highly possible that bacteria can find the cancerous cells
C、molecules cannot carry sensors and actuators
D、to build a cancer-killing bacterium, scientists must create organisms that can perform a series of complicated functions
答案
B
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3910482.html
相关试题推荐
Imagineabacteriumthat,wheninjectedintothebloodstream,wouldtravelt
Imagineabacteriumthat,wheninjectedintothebloodstream,wouldtravelt
[originaltext]F:Mr.Johnson,youhavetraveledtosomanyplacesintheworld.
[originaltext]F:Mr.Johnson,youhavetraveledtosomanyplacesintheworld.
[originaltext]F:Mr.Johnson,youhavetraveledtosomanyplacesintheworld.
TravelmedicineinBritainis[br]Themaininterestoftravelcompaniesdealing
FewmoderntravelwritersexcitemorehostilityandawethanSirWilfredTh
Swiftinventedfamous______inhisworldfamousGulliver’sTravels.A、LilliputB
Gulliver’sTravelswaswrittenby__________.A、JonathanSwiftB、CharlesDickensC
1 Scholarsandstudentshavealwaysbeengreattravelers.Theofficialcasefor
随机试题
CanIhelpyou?[br]Ilikedriving.F
MalnutritionandtheDiseasesofPovertyMalnutritiondisproportionatelyaffe
Hearguedforcefullyand________thattheywerelikelytobankruptthebudget.A、b
以下关于中证全债指数的说法,错误的是()。A.样本包括银行间市场和沪深交易所市场
下列关于《中华人民共和国行政诉讼法》基本规定的说法中,正确的是()①当事人在行政
下列方剂中,遣药配合寓“金水相生”之意的是 A.一贯煎B.六味地黄丸C.百
关于契税的计税依据,下列表述中,正确的有( )。A.以协议方式出让国有土地使用权
关于税法的法定主义原则,下列说法错误的是( )。A.税收法定主义原则是税法至为
甲公司盈利稳定,有多余现金,拟进行股票回购用于将来奖励本公司职工。在其他条件不变
根据《建设工程质量管理条例》,对国家重大技术改造项目实施监督检查的部门是( )
最新回复
(
0
)