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Negeri Sembilan, Malaysia

Futra D.,National University of Malaysia | Heng L.Y.,National University of Malaysia | Jaapar M.Z.,Freshwater Fisheries Research Institute | Ulianas A.,State University of Padang | And 2 more authors.
Analytical Methods | Year: 2016

Molecularly imprinted polymers (MIPs) are generally a more stable material for sensing application. The high selectivity and sensitivity of MIPs for sensors can be achieved if the template molecule is imprinted in the polymer and this makes them an ideal alternative as a recognition element for sensors. A new electrochemical sensor based on molecularly imprinted polymeric microspheres (MIPs) and multi-walled carbon nanotube/gold nanoparticle (MIP-MWCNT-AuNP) modified carbon screen-printed electrodes (SPEs) for the rapid detection of 17β-estradiol (E) hormone in serum samples has been successfully developed. Hydrophobic MIPs were synthesized using photopolymerization in emulsion form. The multi-walled carbon nanotube grafted with gold nanoparticles was firstly deposited onto a carbon screen-printed electrode for the purpose of accelerating electron transfer to the surface of the electrode. The MIP microspheres specific to the 17β-estradiol hormone, prepared via a facile photopolymerization technique, were coated onto the MWCNT-AuNP modified SPE. The presence of 17β-estradiol in biological samples could be detected with the sensor via absorption of 17β-estradiol into the deposited MIPs and this was monitored by differential pulse voltammetry (DPV) at 0.6 V for the reduction of 17β-estradiol. Under optimal conditions, the sensor could detect the concentrations of 17β-estradiol from 1.0 × 10-15 to 1.0 × 10-6 M (R2 = 0.9921), with a detection limit of 2.5 × 10-16 M. The sensor based on MIP microspheres and the MWCNT-AuNP modified electrode demonstrated a stability of 55 days with good reproducibility (RSD < 5%, n = 5) and regenerability (RSD < 4%, n = 5). Using this sensor, the gender of the arowana fish determined via the level of 17β-estradiol using fish serum samples demonstrated good agreement with a conventional test kit based on the immuno-assay method. © 2016 The Royal Society of Chemistry.

Mizuno S.,Salmon and Freshwater Fisheries Research Institute | Urabe H.,Salmon and Freshwater Fisheries Research Institute | Aoyama T.,Salmon and Freshwater Fisheries Research Institute | Omori H.,Freshwater Fisheries Research Institute | And 6 more authors.
Aquaculture | Year: 2012

It is important for the success of the masu salmon, Oncorhynchus masou, stock enhancement program in Hokkaido (northern Japan) to demonstrate physiological problems in hatchery-reared (hatchery) smolt for artificial release. The present study examined changes in liver and gill metabolic parameters in wild and hatchery masu salmon during smoltification and elucidated differences in hepatic and gill metabolism between wild and hatchery fish. As reference to freshwater-adapted wild and hatchery smolt in this study, metabolic parameters of coastal smolt were studied. Yearling wild and hatchery smolting fish were collected from the Ken-ichi River and the Donan Research Branch, which used Ken-ichi river water for fish culture, at the same time every month from March through May 2008. Coastal smolts were caught from Nemuro Bay of Hokkaido in June. Decreased hepatic glycogen content during smoltification, which was observed in wild fish and revealed activation of glycogenolysis, was not found in hatchery fish. Hatchery fish demonstrated a positive change in hepatic ATP content during smoltification, while wild fish showed negative change in the content, which reflected activated consumption of hepatic ATP stores during smoltification. Increases in gill pyruvate kinase activity during smoltification, which were found in wild fish and indicated activation of glycolysis, were not detected in hatchery fish. There was a difference in increased timing of hepatic citrate synthase activity during smoltification between hatchery and wild fish. Increased gill citrate synthase activity during smoltification, which was observed in wild fish and reflected enhancement of the citric acid cycle, was not found in hatchery fish. Hatchery smolt revealed lower liver cytochrome c oxidase activity and transcript levels of some respiratory chain enzymes compared to wild smolt in May, which suggested lower respiratory chain capacity in hatchery fish at mid-smolt stage. On the other hand, there were no remarkable differences in hepatic and gill 3-hydroxyacyl-coenzyme A dehydrogenase related to lipolysis and creatine kinase activities, which operate in resolution of creatine phosphate, during smoltification between hatchery and wild fish. These results suggested hatchery masu salmon had some metabolic problems with carbohydrate metabolism, the citric acid cycle, and the respiratory chain. Our study will give valuable information to improve physiological quality of hatchery smolt for artificial release. © 2010 Elsevier B.V.

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