| Zappert counting chamber | A special, standardised glass slide used for counting cells (especially erythrocytes and leukocytes) and other particulate material in a measured volume of fluid; the central portion is precisely ground in such a manner that the uniformly flat surface is exactly 0.1 mm lower than that of two parallel ridges on which a special, uniformly flat coverslip may be placed; accurately etched lines on the flat central portion form the boundaries of groups of squares of known areas, thereby providing the basis for determining the volume of fluid in which the cells are counted. Glass slides of this type are frequently known as haemocytometers. (05 Mar 2000) |
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| Zappert, Julius | <person> Austrian physician, 1867-1942. See: Zappert counting chamber. (05 Mar 2000) |
| zaratite | <chemical> A hydrous carbonate of nickel occurring as an emerald-green incrustation on chromite. Synonym: emerald nickel. Origin: Named after Gen. Zarata of Spain. Source: Websters Dictionary (01 Mar 1998) |
| zarnich | <chemical> Native sulphide of arsenic, including sandarach, or realgar, and orpiment. Origin: F, fr. Ar. Az-zernikh, fr. Gr. See Arsenic. Source: Websters Dictionary (01 Mar 1998) |
| zarthe | <zoology> A European bream (Abramis vimba). Alternative forms: zaerthe. Source: Websters Dictionary (01 Mar 1998) |
| zati | <zoology> A species of macaque (Macacus pileatus) native of India and Ceylon. It has a crown of long erect hair, and tuft of radiating hairs on the back of the head. Synonym: capped macaque. Source: Websters Dictionary (01 Mar 1998) |
| zauschneria | <botany> A genus of flowering plants. Zauschneria Californica is a suffrutescent perennial, with showy red flowers much resembling those of the garden fuchsia. Origin: NL, named for M. Zauschner, a Bohemian botanist. Source: Websters Dictionary (01 Mar 1998) |
| zea | <botany> A genus of large grasses of which the Indian corn (Zea Mays) is the only species known. Its origin is not yet ascertained. See Maize. Origin: L, a kind of grain, fr. Gr,; cf. Skr. Yava barley. Source: Websters Dictionary (01 Mar 1998) |
| zealotry | The character and behavior of a zealot; excess of zeal; fanatical devotion to a cause. "Enthusiasm, visionariness, seems the tendency of the German; zeal, zealotry, of the English; fanaticism, of the French." (Coleridge) Source: Websters Dictionary (01 Mar 1998) |
| zearalenone | <chemical> (s-(e))-3,4,5,6,8,10-hexahydro-14,16-dihydroxy-3-methyl-1h-2-benzoxacyclotetradecin-1,7(8h)-dione. One of a group of compounds known under the general designation of resorcylic acid lactones. Cis, trans, dextro and levo forms have been isolated from the fungus gibberella zeae (formerly fusarium graminearum). They have oestrogenic activity, cause toxicity in livestock as feed contaminant, and have been used as anabolic or oestrogen substitutes. Pharmacological action: oestrogens, non-steroidal. Chemical name: 1H-2-Benzoxacyclotetradecin-1,7(8H)-dione, 3,4,5,6,9,10-hexahydro-14,16-dihydroxy-3-methyl-, (S-(E))- (12 Dec 1998) |
| zeatin | <molecular biology, plant biology> A naturally occurring cytokinin, originally isolated from maize seeds. Its riboside is also a cytokinin. (18 Nov 1997) |
| zeaxanthin | B,beta-carotene-3,3'-diol;a carotene found in corn, fruits, seeds, and egg yolk; isomeric with xanthophyll. Synonym: zeaxanthol. Origin: Mod. L. Zea, Indian corn, fr. L. Zea, grain + G. Xanthos, yellow, + -in (05 Mar 2000) |
| zeaxanthin epoxidase | <enzyme> An o2-dependent NADPH-dependent epoxidase; catalyses the epoxidation of zeaxanthin to violaxanthin via antheraxanthin; active at the stromal side of the thylakoids of green plants Registry number: EC 1.- Synonym: zea-epoxidase (26 Jun 1999) |
| zeaxanthin glucosyltransferase | <enzyme> Forms zeaxanthin monoglucoside and diglucoside; isolated from erwinia herbicola Registry number: EC 2.4.1.- Synonym: crtx gene product, 3-hydroxy-beta-carotene glycosylase (26 Jun 1999) |
| zeaxanthol | B,beta-carotene-3,3'-diol;a carotene found in corn, fruits, seeds, and egg yolk; isomeric with xanthophyll. Synonym: zeaxanthol. Origin: Mod. L. Zea, Indian corn, fr. L. Zea, grain + G. Xanthos, yellow, + -in (05 Mar 2000) |