1)The transposon Tn5 was used to create a library of 50,000 Escherichia coli mutant strains having...

1)The transposon Tn5 was used to create a library of 50,000 Escherichia coli mutant strains having random Tn5 insertions in their chromosomal genes. A suicide delivery plasmid vector that carries Tn5 was used for this purpose. Explain how and why a suicide delivery plasmid was used to generate this library and give one (1) example of how you would screen this library to find mutants with Tn5 insertions in specific genes of interest, for example, in the lac (lactose) operon.

2) Describe the experiments by Robert Koch that underpin Koch’s postulates. What are FOUR (4) reasons why these postulates could be too restrictive?

Expert Solution

Answer-1 the suicide plasmid are used to duplicate the gene and alternatively as the disrupting the gene and producing incomplete gene in the host. To detect the mutant the cells should be cultured in a media containing the antibacterial drugs in low concentration and then the sensitivity and functioning of microbe should be observed . If there is high sensitivity even to low concentration of drug then the microbe will be mutant.

Answer-2 Robert kouch isolates microbes from a diseased rat and culture them to obtain the more microbes and then reinoculate them in healthy rat. They showed the same pathogenicity.

His postulates ate-

The pathogen should be find only in diseased person not in healthy person.

It should be grown in pure culture.

The cultured microbes should be introduced in a healthy subject and they should be capable of causing same disease.

It should be reisolate from diseased and should be compared to previously isolated and should be similar to them.

gladiator answered 1 year ago

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