Now to start with, the plasmid is usually shown in a diagram like this as a circle.

首先要说的是,质粒通常用图中这个环形来表示

耶鲁公开课 - 生物医学工程探索课程节选

You've got negative charge in motion, and it's in a circular orbit.

负电荷在运动，它们处在一个环形的轨道中。

麻省理工公开课 - 固态化学导论课程节选

The first step is we had to be able to take this circular DNA and cut it to create a site for our new gene to be added.

第一步是切割环形DNA,以创造出一个整合新基因的位点

耶鲁公开课 - 生物医学工程探索课程节选