Alexander Scott

Learn More
A procedure previously used for sex steroids was adapted to extract free cortisol and cortisone from water samples taken from rainbow trout Oncorhynchus mykiss tanks. Both corticosteroids could be readily detected by radioimmunoassay (RIA), with cortisol being predominant. All stages of the sampling, extraction and RIA procedure were validated for cortisol.(More)
Previous studies have demonstrated that ovulatory goldfish synthesize and release a variety of steroids into the water, where some of them function as sex pheromones. Among the steroids which have been measured are free androstenedione, testosterone, 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P), 17 alpha,20 beta,21-trihydroxy-4-pregnen-3-one(More)
The problem of finding good lower bounds on the size of the largest bipartite subgraph of a given graph has received a fair amount of attention. In particular, improving a result of Erdős ([10]; see also [11] for related problems), Edwards [9] proved the essentially best possible assertion that every graph with n vertices and m edges has a bipartite(More)
Measurement of fish steroids in water provides a non-invasive alternative to measurement in blood samples, offering the following advantages: zero or minimal intervention (i.e. no anaesthetic, bleeding or handling stress); results not being biased by sampling stress; repeat measurements on the same fish; the possibility of making non-lethal measurements on(More)
In 1996, The Centre for Environment, Fisheries and Aquaculture Science (CEFAS) initiated a project to establish whether oestrogenic materials are present in UK estuarine and marine waters at biologically significant concentrations, and to investigate some of the possible effects which these may have in flounder (Platichthys flesus). Early results are(More)
The androgen 11-ketotestosterone (11-KT) plays an important role in reproductive physiology and behaviour in male teleosts. In the three-spined stickleback, Gasterosteus aculeatus, the plasma concentrations of 11-KT are related to the breeding status of the fish. Sticklebacks are relatively small (generally less than 1g) and in order to obtain sufficient(More)
Alexander P. Scott1,9), Katharina Hirschenhauser2), Nicole Bender3), Rui Oliveira4), Ryan L. Earley5), Marion Sebire6), Tim Ellis1), Michael Pavlidis7), Peter C. Hubbard8), Mar Huertas8) & Adelino Canario8) (1 Centre for Environment, Fisheries and Aquaculture Science, Barrack Road, The Nothe, Weymouth DT4 8UB, UK; 2 Konrad Lorenz Research Station,(More)
Dab (Limanda limanda) ovarian fragments were incubated in vitro with either [4,7-3H]pregnenolone or 17 alpha-hydroxy[1,2,6,7-3H]progesterone to investigate the pattern of steroidogenesis. A major enzyme found in the dab ovary was 20 alpha-hydroxysteroid dehydrogenase. Among the steroids that were tentatively identified in ovarian incubates were 17 alpha,20(More)
We show that reproductively mature male sea lampreys release a bile acid that acts as a potent sex pheromone, inducing preference and searching behavior in ovulated female lampreys. The secreted bile acid 7alpha,12alpha,24-trihydroxy-5alpha-cholan-3-one 24-sulfate was released in much higher amounts relative to known vertebrate steroid pheromones and may be(More)
Previous studies have demonstrated that ovulatory female goldfish release a variety of sex steroids into the water where they function as a pheromonal blend dominated by C21 steroids that stimulates male hormone release, sperm production and behavior. This study investigated whether male goldfish might also release sex steroids with pheromonal activity. It(More)