| 释义 |
ˈdownˈstream, adv. (a., n.)
Also down stream, down-stream.
[down prep. 3.]
a. Down the stream, in the direction of the current, towards the mouth of a river. Also fig.
1706in Rec. Plymouth (Mass.) (1889) I. 26 Bounded by said river..down stream unto the upper end of the meadow. 1864Carlyle Fredk. Gt. IV. 560 Königstein, a little down-stream of Schandau. 1865Mrs. Stowe House & Home P. 316 There is a general tendency to let all sorts of old forms and observances float down-stream. 1869Blackmore Lorna D. vii, Even an otter might float downstream. 1878R. L. Stevenson Inland Voy. 196 Canoeing was easy work..to keep the head down stream. 1929Belloc Joan of Arc iii. 62 The French forces lay downstream. 1957P. Caraman Henry Morse vii. 66 Across the river, about a mile down⁓stream, a path ran from the bank.
b. as adj. and quasi-n. Also fig.
1842American Pioneer I. 70 Steam-boats seem almost to say, we will do your up-stream business for nothing, if you will give us your down-stream business. 1891W. Morris News from Nowhere (ed. 2) ii. 8 Even the up-stream bridges..are scarcely daintier, and the down-stream ones are scarcely more dignified and stately. 1934J. L. Myres in E. Eyre European Civilisation I. ii. 115 There were certainly casual immigrants from down-stream. 1954R. St. B. Baker Sahara Challenge iii. 39 The down-stream rush of water is decreased. 1963Economist 21 Sept. 1042/2 Much larger ‘downstream’ investment.
Senses a, b in Dict. become 1 a, b. Add: 2. Biol. In the direction in which transcription occurs. Opp. *up-stream adv. 3.
1977Cell XII. 19 (caption) The model presents a mechanism by which different segments of an RNA molecule encoded at widely spaced sites on the DNA are brought together to form a continuous leader sequence, which is then attached to various structural RNAs encoded downstream. 1978Science 5 May 502/1 The 5′ end of the bulk of SV40 early mRNA lies just downstream from these sequences. 1990EMBO Jrnl. IX. 2632/1 In plasmid pToto.2, we have provided the nsP2 gene with an initiation codon preceding the Ala1 codon, and an amber stop codon immediately downstream of the 3′ terminal Ala807 codon. |