When was the first extra $DNA$ fragment successfully inoculated into $E. coli$ using a plasmid?

It is used to detect $HIV$ in suspected $AIDS$ patient and detect mutations in genes in suspected cancer patient too.

Upon exposure to $UV$ radiation,$DNA$ stained with ethidium bromide will show:

The optimum temperature for polymerisation in $PCR$ is $....$ while the enzyme responsible for the mentioned step can tolerate temperatures up to $....$. Select the correct option according to the blanks.

Consider the following figure of a stirred-tank bioreactor and identify $A, B, C$,and $D$.

In a bioreactor,through which system can a small volume of culture be withdrawn periodically?