问题 多项选择题

检测致泻性大肠埃希菌肠毒素的方法有

A.免疫荧光试验检测LT和ST

B.单项琼脂扩散试验检测ST

C.酶联免疫吸附试验检测LT和ST

D.双向琼脂扩散试验检测LT

E.乳鼠灌胃试验检测sT

答案

参考答案:C,D,E

解析:致泻性大肠埃希菌的肠毒素有不耐热肠毒素(LT)和耐热肠毒素(ST)。LT可用双向琼脂扩散试验检测,ST可用乳鼠灌胃试验检测。酶联免疫吸附试验用双抗体夹心法检测LT,抗原竞争法检测ST。

单项选择题

I got a job teaching special education at a school in Coachella, California, a desert town about 170 miles from home. It was no (1) job. Street gangs (2) around the school after dark.

"Be careful, " Dad warned me during one of my frequent weekend (3) home. He was concerned about my living (4) , but I needed to be on my own.

One evening, I stayed after school to rearrange my classroom. (5) , I turned out the light and closed the door. Then I (6) toward the gate. It was (7) ! I looked around. Everyone had gone home.

After (8) all the exits, I found just enough (9) to squeeze under a gate in the back of the school. Then I walked toward my car, parked in a field behind the building.Suddenly I heard voices. I (10) around and saw at least eight boys following me. (11) my pace, I reached into my shoulder bag to get my key. I (12) all over the inside of my handbag. But the key wasn’t (13) ! Dear Lord, please help me, I prayed (14) . Suddenly, my fingers touched a loose key in my purse. I didn’t even know if it was for my car, but I took it out and (15) it. It worked!I opened the door, slid in and locked it—just (16) the teenagers surrounded the car. Trembling , I started the engine and (17) away. When I returned to my apartment, the phone was ringing. It was my Dad. I didn’t tell him about my experience; I didn’t want to (18) him. "Oh, I forgot to tell you!" He said, "I had a (n) (19) car key made and slipped it into your purse—just (20) you ever need it. \

9().

A.time 

B.ground 

C.strength 

D.room

选择题