In contrast, virtually all biotechnologically used plasmids ( such as pUC18, pBR322 and derived vectors ) do not contain toxin-antitoxin addiction systems and thus need to be kept under antibiotic pressure to avoid plasmid loss.
2.
To understand forces and velocities, discussed here, one must understand what is meant by a " N ) may be added and subtracted, graphically, by positioning tips and tails of the arrows, representing the input variables and drawing the resulting derived vector.
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