Item – Theses Canada

OCLC number
1007011814
Link(s) to full text
LAC copy
LAC copy
Author
Kiparissis, Yiannis,1962-
Title
Effects of flavonoids and other phytochemicals on fish CYP1A monooxygenases, embryonic and reproductive development.
Degree
Ph. D. -- Trent University, 2001
Publisher
Ottawa : National Library of Canada = Bibliothèque nationale du Canada, [2001]
Description
4 microfiches
Notes
Includes bibliographical references.
Abstract
The purpose of this study was to demonstrate that biological responses in fish such as induction of CYP1A-dependent monooxygenases, embryonic defects, and reproductive failure that are observed in feral fish exposed to bleached kraft mill effluents (BKME) may be attributed to exposure to phytochemicals. Aqueous leachates from wood pulp and selected phytochemicals induced ethoxyresorufin-O-deethylase (EROD) in rainbow trout ('Oncorhynchus mykiss'). The same phytochemicals caused a multitude of developmental abnormalities in exposed embryos of Japanese medaka ('Oryzias latipes '). Further work with flavonoids, which are a specific class of phytochemicals, indicated that molecular structure and position of hydroxy-substitution are variables that affect EROD induction potency and embryotoxicity. The flavonoid compounds, flavone, flavonol, flavanone, chrysin, apigenin, naringenin, galangin, genistein, catechin, kaempferol and quercetin all altered gonadal development in Japanese medaka. Intersex gonads, delayed maturation, reduced numbers of germ cells, ovarian atresia and alterations to secondary sex characteristics were evident in medaka from most treatments. Results from 'in vitro ' studies showed that flavonoids may affect reproductive development in fish by binding to either the estrogen or androgen receptor, or by binding to the sex steroid carrier proteins. Analysis of BKME by liquid chromatography mass spectrometry indicated that the isoflavonoid, genistein was present in wood pulp and in mill effluent at ppb concentrations. Thus, flavonoids may be responsible for the biological effects observed in fish downstream of pulp mills.
ISBN
0612580024
9780612580022