Effects of long-term temperature acclimation on thyroid hormone deiodinase function, plasma thyroid hormone levels, growth, and reproductive status of male Atlantic cod, Gadus morhua.

The recent collapse of the Northwestern Atlantic cod fisheries has coincided with a cooling of water temperatures. During this time the condition factor of cod has been poor. The objective of the present study was to determine the effects of long-term temperature acclimation on growth reproduction and thyroid function in laboratory held Atlantic cod (Gadus morhua).

Effect of cysteine substitutions on the mitogenic activity and stability of recombinant human keratinocyte growth factor.

Human Keratinocyte growth factor (hKGF), a member of the FGF family of growth factors, contains five cysteines at amino acid positions 1, 15, 40, 102, and 106. We expressed five cysteine mutants of hKGF in which the cysteines were cumulatively replaced with alanine or serine, starting with cysteine-1. Recombinant hKGF has an inherently higher mitogenic activity and stability to heat and acid than reported for glycosylated hKGF.

Gonadotropin action on brook trout sperm duct epithelium: ion transport stimulation mediated by cAMP and Ca2+.

The isolated sperm duct epithelium from the brook trout Salvelinus fontinalis serves as a model for gonadotropin (GtH) action and is the only example of direct GtH stimulation of epithelial ion transport. In response to purified salmonid carbohydrate-rich GtH added to either the luminal or blood side of the epithelium, the duct actively secretes K+ (measured as 86Rb+ fluxes) and actively reabsorbs Na+ (measured by 22Na+ fluxes or as short circuit current, Isc). As a consequence of the ion transport, the seminal plasma has low Na+ concentration and high K+ content that in turn keeps developing sperm quiescent prior to spawning.

Steroids involved with final oocyte maturation in the winter flounder.

A number of androgens and progestogens including 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20-P) were examined in female winter flounder as possible maturation inducing steroids (MIS). During final oocyte maturation serum levels of testosterone (T) and 17 beta-hydroxy-5 beta-androsten-3-one (5 beta-T) peaking at over 200 ng/ml and pregnenolone (PE) at 40 ng/ml were the predominant steroids found from each major group. High levels of T and 5 beta-T were correlated with oocyte stages characterized by germinal vesicle migration.

Growth enhancement in transgenic Atlantic salmon by the use of an "all fish" chimeric growth hormone gene construct.

We have developed an "all fish" growth hormone (GH) chimeric gene construct by using an antifreeze protein gene (AFP) promoter from ocean pout linked to a chinook salmon GH cDNA clone. After microinjection into fertilized, nonactivated Atlantic salmon eggs via the micropyle, transgenic Atlantic salmon were generated. The presence of the transgene was detected by polymerase chain reaction (PCR) using specific oligonucleotide primers.