Definition of "plasmid" [plas•mid]

• A circular, double-stranded unit of DNA that replicates within a cell independently of the chromosomal DNA. Plasmids are most often found in bacteria and are used in recombinant DNA research to transfer genes between cells. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "This plasmid is optimal for nonmammalian expression. pDsRed1-1: This plasmid contains an RFP gene that has been altered for human expression of RFP (DsRed1)."
• "Co-transfection of human TLR2 with increasing amounts of the expression plasmid encoding alphaT2ib into HEK293 cells demonstrated high efficiency of the TLR2-alphaT2ib interaction."
• "This conclusion was further supported by the fact that large part of the secretome was found to be coded by a piece of extra-chromosomal DNA called plasmid, which is, simply, the most mobile part of the whole bacterial genome"