| 释义 |
plasmid Biol.|ˈplæzmɪd|
[f. plasm + -id (cf. id, chromatid).]
Any genetic structure in a cell that can replicate independently of the chromosomes; esp. one in the cytoplasm of a bacterium.
1952J. Lederberg in Physiol. Rev. XXXII. 403, I propose plasmid as a generic term for any extrachromosomal hereditary determinant. Ibid., The taxonomic classification of plasmids as viruses, symbionts, or plasmagenes should not obscure careful descriptions of their function, hereditary or pathological, or both. Ibid. 414, κ, a plasmid in Paramecium aurelia. Ibid. 425 This review has contrasted the various forms of plasmid: the hereditary parasites as against the functionally coordinated plasmagenes, with the mutualistic endosymbionts somewhere between. 1964Daily Mirror 24 July 8/2 The Rogue Bug's real name is RTF plasmid—R.T.F. stands for Resistance Transfer Factor. It is a tiny particle that appears to move from one bacterial cell to another, carrying with it a built-in resistance to new drugs. 1969A. M. Campbell Episomes i. 13 Episomes are thus distinguished from chromosomal genes on the one hand and obligately cytoplasmic elements (plasmids) on the other. 1973R. G. Krueger et al. Introd. Microbiol. xv. 421/1 There are..transmissible plasmids or sex factors like the F factor, which promote their own transfer to recipient bacteria, and there are nontransmissible plasmids which are incapable of transferring themselves to recipient cells. 1975Sci. Amer. July 25 It has been called plasmid engineering, because it utilizes plasmids to introduce the foreign genes... Because of the method's potential for creating a wide variety of novel genetic combinations in microorganisms it is also known as genetic engineering. 1977Time 18 Apr. 48/1 They possess much smaller closed loops of DNA, called plasmids—which consist of only a few genes. |