| 释义 |
viroid Biol.|ˈvaɪərɔɪd|
[f. virus + -oid.]
1. A virus-like particle. Also attrib. or as adj. Now disused in favour of next sense.
1946E. Altenburg in Amer. Naturalist LXXX. 559 It is conceivable that there exist ultra-microscopic organisms which are akin to viruses but which are useful symbionts, and that these symbionts occur universally within the cells of larger organisms. We might call these supposed symbionts viroids. 1953S. E. Luria Gen. Virol. xviii. 361 Mutations of viroids could also give rise to nontransmissible, abnormal plasmagenes and be responsible..for the tumoral transformation of cells. 1959Oxf. Mag. 26 Feb. 286/2 The relationship between viruses and other ‘viroid’ particles. 1963New Scientist 20 June 652/1 If blind natural selection could conjure man out of a viroid in a couple of billion years, what could not man's conscious and purposeful efforts achieve?
2. An infectious entity similar to a virus but smaller and consisting of a strand of nucleic acid only, without the protein coat characteristic of a virus.
1971T. O. Diener in Virology XLV. 426/1, I propose the term ‘viroid’ for such entities. Altenburg (1946) introduced this term to designate hypothetical symbionts, akin to viruses... If, however, the ‘viroid’ is redefined operationally and in modern terms to encompass nucleic acid species with the properties discussed here, the term serves a useful function. To distinguish pathological conditions incited by viroids from those incited by viruses, the term ‘viroid disease’ is proposed. 1979Nature 4 Jan. 60/2 Viroids are the smallest replicating pathogenic agents known. 1981Times 2 Apr. 16 There is a parallel class of agents which infect plants, the viroids, which consist solely of strands of RNA. |