For Hamas leaders, this is,in some ways, a bigger victory than persuading Israel to lift its restriction on goods entering the territory.
VOA: standard.2010.06.16
Or you could ask the question, I have this restriction enzyme, at what regions on this plasmid will it cut?
你也可以这样问,我的这种限制性内切酶,会从质粒的哪个区域切开呢
This restriction enzyme was found in a natural source, it was found in a micro-organism called E.coli.
这个限制性内切酶源于自然界,是从名为大肠杆菌的微生物中发现的
What are the properties of this restriction enzymes?
这种限制性内切酶的特性是什么
We're going to take a chromosomal DNA, we're going to digest it with this restriction enzyme, we're going to put it in this tube and run it on a gel, and we're going to see what results down here.
我们取一条染色体DNA,然后用限制酶进行分解,接着再放,在凝胶上进行电泳,之后看看结果如何
In this case, this particular restriction enzyme cuts symmetrically like this, but not at the same point.
在我们这种情况下,这个限制性内切酶总是这样对称地切割,但两条链切割的位点不一样
This takes advantage of the very specific properties of restriction enzymes.
这利用了限制酶的独特性质
If you have DNA fragments, so this is DNA that you've cut up into fragments using restriction enzymes for example.
如果你有DNA片段,例如有一段你用限制酶,切割成片段的DNA
This gives you a biological mechanism for cutting, using restriction enzymes, and then you denature so that it falls apart, and then you renature so that it comes back together.
这是一种切割DNA的生物机制,用限制性内切酶,改变DNA的性质让它打开,然后让它合起来恢复它的性质
If I took this same restriction enzyme and tried to cut the chromosomal DNA of a sickle patient, it wouldn't cut at that point because the wrong sequence is there.
而如果我用同样的限制酶,去切割病人的染色体DNA,那该酶是不会起作用的,因为基因序列不对
This particular restriction enzyme here recognizes this sequence,GAATTC.
这里的这种限制性内切酶,只识别序列GAATTC
Well one way you could do it is by saying 'if I have this one base pair difference then this sequence is going to be cut by a specific restriction enzyme that recognizes the sequence CTGAGGA'.
一种方法是通过考虑,"如果我有这个不同的碱基对,那该序列必然会,被特定的限制酶识别并切割,这个特定的限制酶能识别,CTGAGGA "
In a normal cell DNA that DNA in the normal cell - this DNA gets cut by the restriction enzyme, so the sickle gene ends up - so that hemoglobin gene ends up in two pieces.
一个正常细胞的DNA,正常细胞里的DNA,会被限制酶所剪切,因此镰状血红蛋白基因--,不对,是正常血红蛋白基因被切成两段
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