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Nocillado J.N.,University of The Sunshine Coast | Nocillado J.N.,Australian Seafood Cooperative Research Center | Zohar Y.,University of Maryland Baltimore County | Biran J.,Hebrew University of Jerusalem | And 2 more authors.
General and Comparative Endocrinology | Year: 2013

The kisspeptin system is now accepted as a key regulator of vertebrate reproductive function, particularly the onset of puberty. In teleosts, the stimulatory effect of exogenous kisspeptins has been demonstrated mainly at the hypothalamic and pituitary levels of the reproductive axis, with very limited information pertaining to gonadal response. We determined the effect of chronic peripheral administration of the conserved kisspeptin decapeptides (YNLNSFGLRY or Kiss1-10; and FNFNPFGLRF or Kiss2-10) on gonadal development of pre-pubertal yellowtail kingfish (Seriola lalandi), a Perciform teleost, during the breeding and non-breeding season. We utilized slow-release implants to chronically deliver the synthesized peptides, which were based on the yellowtail kingfish kiss1 and kiss2 cDNA sequences that we isolated. The expression level of kiss2r and gnrh1 in the brain or hypothalamus did not vary between treated and control groups. Pituitary expression of fshβ and lhβ was upregulated only with Kiss1-10 treatment regardless of the season. Based on histological evidence, gonadal development was stimulated in male fish with either Kiss1-10 or Kiss2-10, with Kiss2-10 being more effective during the non-breeding period. Overall, our results suggest that kisspeptins modulate the early gonadal development of male yellowtail kingfish, however that may vary with the breeding season. © 2013 Elsevier Inc.. Source


Stewart I.,South Australian Research And Development Institute | Stewart I.,Australian Seafood Cooperative Research Center | Stewart I.,University of Queensland | McLeod C.,South Australian Research And Development Institute
Journal of AOAC International | Year: 2014

Mouse bioassays have been a mainstay for detecting harmful concentrations of marine algal toxins in shellfish for over 70 years. Routine monitoring involves intraperitoneal injection of shellfish extracts into mice; shellfish contaminated with algal toxins are thus identified by mortality in exposed mice. With the advent of alternative test methods to detect and quantify specific algal toxins has come increasing criticism of enduring use of mouse bioassays for shellfish safety testing. However, the complete replacement of shellfish safety mouse bioassays by chemical, antibody-based, and functional assays has been and will continue to be a gradual process for various reasons, including skills availability and instrument costs for chromatography-based toxin monitoring. Mouse bioassays for shellfish safety testing do not comply with modern standards for laboratory animal welfare, specifically the requirement in published official methods for death as a test outcome. Mouse bioassays for algal biotoxins in shellfish, as well as fundamental algal toxin research endeavors using in vivo models, are amenable to revision and refinement from a humane endpoints perspective. Regulated hypothermia may be a useful and easily acquired nonlethal toxicological endpoint; objective determination of neuromuscular blockade may allow algal neurotoxin testing and research to enter the domain of humane endpoints evaluation. Relinquishing reliance on subjective test endpoints, including death, will likely also deliver collateral improvements in assay variability and sensitivity. © 2014 Publishing Technology. Source


Anderson K.,University of The Sunshine Coast | Anderson K.,Australian Seafood Cooperative Research Center | Swanson P.,National Oceanic and Atmospheric Administration | Pankhurst N.,Griffith University | And 3 more authors.
Aquaculture | Year: 2012

Exposure of female Atlantic salmon to elevated temperature can result in a dramatic reduction in egg fertility and embryo survival. Reductions in plasma 17β-estradiol (E 2) levels are associated with much of the observed reduction in reproductive performance; however, the molecular basis for reduced E 2 levels remains unknown. This study examined gene expression of ovarian steroidogenic enzymes and plasma levels of gonadotropins in maiden and repeat spawning Atlantic salmon exposed to higher than normal temperatures. Circulating levels of follicle stimulating hormone (Fsh) were significantly elevated in both maiden and repeat spawning fish maintained at 22°C compared to 14°C during vitellogenesis, but plasma luteinising hormone levels were mostly unaffected. In contrast, gene expression of the ovarian p450 aromatase a and cholesterol side chain cleavage protein were depressed at 22°C compared to 14°C. Hepatic gene expression of estrogen receptor alpha did not change with thermal challenge. The results show that the ovarian response to Fsh is inhibited at 22°C, at least partly as a result of reduced expression of genes coding for steroidogenic enzymes. © 2011 Elsevier B.V. Source


Fluckiger M.,CSIRO | Fluckiger M.,University of Tasmania | Fluckiger M.,Australian Seafood Cooperative Research Center | Brown M.R.,CSIRO | And 2 more authors.
Food Chemistry | Year: 2011

Near infrared reflectance spectroscopy (NIRS) was used to predict glycogen concentrations in the foot muscle of cultured abalone. NIR spectra of live, shucked and freeze-dried abalones were modelled against chemically measured glycogen data (range: 0.77-40.9% of dry weight (DW)) using partial least squares (PLS) regression. The calibration models were then used to predict glycogen concentrations of test abalone samples and model robustness was assessed from coefficient of determination of the validation (R2val) and standard error of prediction (SEP) values. The model for freeze-dried abalone gave the best prediction (R2val 0.97, SEP = 1.71), making it suitable for quantifying glycogen. Models for live and shucked abalones had R2val of 0.86 and 0.90, and SEP of 3.46 and 3.07 respectively, making them suitable for producing estimations of glycogen concentration. As glycogen is a taste-active component associated with palatability in abalone, this study demonstrated the potential of NIRS as a rapid method to monitor the factors associated with abalone quality. © 2010 Elsevier Ltd. All rights reserved. Source


Anderson K.C.,University of The Sunshine Coast | Anderson K.C.,Australian Seafood Cooperative Research Center | Elizur A.,University of The Sunshine Coast
BMC Research Notes | Year: 2012

Background: The use of quantitative real-time polymerase chain reaction (qPCR) has become widespread due to its specificity, sensitivity and apparent ease of use. However, experimental error can be introduced at many stages during sample processing and analysis, and for this reason qPCR data are often normalised to an internal reference gene. The present study used three freely available algorithms (GeNorm, NormFinder and BestKeeper) to assess the stability of hepatically expressed candidate reference genes (Hprt1, Tbp, Ef1α1 and -tubulin) in two experiments. In the first, female Atlantic salmon (Salmo salar) broodstock of different ages were reared at either 14 or 22°C for an entire reproductive season, therefore a reference gene that does not respond to thermal challenge or reproductive condition was sought. In the second, estrogen treated juvenile salmon were maintained at the same temperatures for 14 days and a reference gene that does not respond to temperature or estrogen was required. Additionally, we performed independent statistic analysis to validate the outputs obtained from the program based analysis. Results: Based on the independent statistical analysis performed the stability of the genes tested was Tbp > Ef1α1 > Hprt1 > β-tubulin for the temperature/reproductive development experiment and Ef1α1 > Hprt1 > Tbp for the estrogen administration experiment (β-tubulin was not analysed). Results from the algorithms tested were quite ambiguous for both experiments; however all programs consistently identified the least stable candidate gene. BestKeeper provided rankings that were consistent with the independent analysis for both experiments. When an inappropriate candidate reference gene was used to normalise the expression of a hepatically expressed target gene, the ability to detect treatment-dependent changes in target gene expression was lost for multiple groups in both experiments. Conclusions: We have highlighted the need to independently validate the results of reference gene selection programs. In addition, we have provided a reference point for those wishing to study the effects of thermal challenge and/or hormonal treatment on gene stability in Atlantic salmon and other teleost species. © 2011 Anderson; licensee BioMed Central Ltd. Source

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