Where does the replication of $DNA$ begin?

For providing evidence in favour of semiconservative way of $DNA$ replication, Taylor, Woods, and Hughes performed experiments on:

For proving the semi-conservative mode of replication of $DNA$,$E. coli$ were first grown in a medium containing?

Taylor and his colleagues proved that $DNA$ in chromosomes also replicates semi-conservatively. Which organism did they use for this experiment?

During the replication of a bacterial chromosome,$DNA$ synthesis starts from the origin of replication and proceeds in a.....

Which bacteria provided the first evidence that $DNA$ replication is semi-conservative?