| 释义 |
zygo-|zaɪgəʊ, zɪgəʊ|
before a vowel properly zyg-, repr. Gr. ζυγο-, combining form of ζυγόν yoke; occurring in various scientific terms, of which the more important will be found in their alphabetical places. (In terms of Biology the prefix often refers to conjugation or zygosis as a method of reproduction: see conjugation 5.)
zygoˈcardiac a. [cardiac A. 4], denoting an ossicle in the stomach of the crayfish and other crustaceans (see quot., and cf. pterocardiac, urocardiac). ˈzygodont a. [Gr. ὀδούς, ὀδοντ- tooth], having molar teeth with an even number of cusps arranged in pairs; having cusps thus arranged, as a molar tooth. zygoˈgenesis [-genesis], reproduction involving the formation of a zygote; so zygogeˈnetic a. ˈzygomere Cytology [-mere], a site on a chromosome thought to be responsible for the initiation of pairing between homologous chromosomes during zygotene in eukaryotes. zygoˈnema Cytology [a. F. zygonema (V. Grégoire 1907, in La Cellule XXIV. 371), f. Gr. νῆµα thread], † (a) a chromosome at zygotene; (b) = zygotene; now rare. zygoneurous |-ˈnjʊərəs| a. [Gr. νεῦρον nerve], applied to an arrangement of the nervous system in certain gastropod molluscs, in which the pallial nerve of each pleural ganglion unites directly with the ganglion of the visceral commissure of its own side (opp. to dialyneurous); so zygoˈneury, zygoneurous condition. zygophiuran |-ɒfɪˈjʊərən| a. and n., belonging to, or a member of, the division Zygophiuræ of ophiuroids, having special structures which limit the movement of the ossicles of the arms (cf. zygospondyline below). ˈzygophore Bot. [-phore], a differentiated hypha in Zygomycetes that takes part in conjugation; hence zygoˈphoric a. ˈzygophyte |-faɪt| [Gr. ϕυτόν plant], a plant which reproduces by conjugation. zyˈgopterid n. and a. [Gr. πτερόν wing], a member of, or belonging to, the division Zygopterides or Zygoptera of dragon-flies, having all the wings nearly or quite equal in size. ˈzygosome Cytology [ad. G. zygosom (E. Strasburger 1904, in Sitzungsber. d. k. Preuss. Akad. d. Wissensch. 606): see -some4] = bivalent n. ˈzygosperm [Gr. σπέρµα seed] = zygospore. ˈzygosphere |-sfɪə(r)| [after oosphere], either of the two conjugating cells or gametes which form a zygospore. zygoˈspondyline a. [Gr. σπόνδυλος vertebra, joint], applied to those ophiuroids in which the arms are incapable of being coiled round straight objects, the movements of their ossicles being limited by internal pits and processes. ˈzygostyle |-staɪl| [style 10] (see quot.). zygoˈzoospore, a zoospore formed by conjugation; a motile zygospore.
1877Huxley Anat. Inv. Anim. vi. 319 A large, elongated postero-lateral or *zygocardiac ossicle.
1888Amer. Naturalist XXII. 832 The *zygodont (quadritubercular) type.
1950Adv. Genetics III. 194 The most common mode of animal reproduction is, however, sexual reproduction or gamogony or *zygogenesis. 1973B. J. Williams Evolution & Human Origins iii. 37/2 It [sc. random genetic drift] includes all events that lead to sampling error in random zygogenesis. 1950Adv. Genetics III. 198 In other parthenogenetic animals both parthenogenetic and zygogenetic reproduction are present. 1978Biol. Bull. CLV. 273 (heading) Artemia hemoglobins: genetic variation in parthenogenetic and zygogenetic populations.
1966J. Sybenga in Genetica XXXVII. 188 General occurrence of localization of the function of initiation of chromosome pairing (long-distance attraction) in discrete units on specific loci is considered a useful working hypothesis. In analogy to ‘centromere’, ‘chromomere’ and ‘telomere’ the term ‘*zygomere’ is proposed for such units. 1981Cytologia XLVI. 527 Since the bivalent formation has not been disturbed, at least one of two zygomeres seems to be able to have a complete activity.
1911Q. Jrnl. Microsc. Sci. LVII. 32 The debatable stages of the meiotic prophases in which parasyndesis and its associated phenomena occur—leptonema, *zygonema..—have been dealt with by many experienced cytologists. Ibid. 33 By the time the zygonema is fairly far advanced we do get appearances not unlike what may occasionally..be found in the condensation of a somatic chromosome. 1976Nature 8 Apr. 534/2 It is generally known that during zygonema (stages XII–XIV in rat spermatogenesis) the homologous sets of sister chromatid pairs begin to come together and associate with one another.
1901Proc. Zool. Soc. 466 A Vivipara possessing a single *zygoneurous connection on the left and the normal dialoneurous relationship of the nerves upon the right.
1892Ibid. 182 For the *Zygophiurans assistance in classification will be gained from Ljungman's well-known work.
1904A. F. Blakeslee in Science 3 June 866/1 In all species of both homo- and heterothallic groups..the swollen portions (progametes) from which the gametes are cut off do not grow toward each other..but arise as a result of the stimulus of contact between more or less differentiated hyphæ (*zygophores). 1970J. Webster Introd. Fungi ii. ii. 116 When two compatible strains approach each other aerial club-shaped branches or zygophores develop which show directional growth towards zygophores of the opposite strain. Zygophores of the same strain repel each other.
1904*Zygophoric [see heterogamic a.]. 1978Canad. Jrnl. Bot. LVI. 1061 One or more slender, lateral zygophoric filaments proliferate from the subterminal portion of a septate, erect hypha.
1885G. L. Goodale Physiol. Bot. 439 note, The sexual process in *Zygophytes is characterized by the confluence of the protoplasmic masses of two very similar cells by which a new mass if formed as the starting-point of the new individual.
1900W. J. Lucas Brit. Dragonflies 53 A *Zygopterid [wing]. Ibid. 34 Nymph of a Zygopterid Dragonfly.
1905Ann. Bot. XIX. 249 A similar operation of the law of chance has been suggested by Strasburger ('04) in the separation of the chromatin granules as a result of the division of the ‘*zygosome’. 1910[see parasynaptic adj. s.v. para-1 1]. 1974Jrnl. Heredity LXV. 257/1 The varying amounts of the q segments present in the zygosome may account in large measure for the physical and mental deviation of these mongoloid patients from the usual spectrum of characteristics typical of mongoloids bearing three independent chromosomes 21.
1880A. W. Bennett & Murray in Q. Jrnl. Microsc. Sci. XX. 417 The conjugated *zygospheres..constitute a *zygosperm.
1892Proc. Zool. Soc. 1 Mar. 178 To regard the streptospondyline type [of ophiuroids] as earlier than the *zygospondyline.
1881Mivart Cat 463 The caudal vertebræ are few and end in a bone, shaped somewhat lika a plough⁓share, called the *zygostyle.
1881Nature 28 July 292 Family Protococcaceæ. Genus Chlorochytrium... Each cell becomes resolved into spherical zoospores, which upon leaving the mother-cell conjugate within the gelatinous envelope. The *zygozoospores before becoming surrounded with a membrane make their way..into the intercellular spaces of living plants. |