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- Einarsdottir, Ingibjörg, 1951, et al.
(författare)
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PITUITARY HORMONE PURIFICATION BY CONTINUOUS-ELUTION ELECTROPHORESIS
- 2006
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Ingår i: 7th International Congress on the Biology of Fishes, Book of Abstracts.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Widely used methods for peptide hormone purification, such as gel filtration chromatography combined with rpHPLC, are time-consuming and often give low yields and instable proteins. The Model 491 Prep Cell from Bio-Rad provides a continuous-elution electrophoresis technique to separate proteins. The protein mixture runs through a cylindrical gel, proteins are separated by size and charge, as they elute from the matrix and are collected using a fraction collector. Sub-samples are assessed by SDS-PAGE and protein identity is verified by Western blot analysis. We applied this technique to separate putative hormones from adult Atlantic halibut pituitaries. Soluble proteins from homogenized pituitaries were denatured and subjected to continuous-elution electrophoresis. The fractions sampled contained purified proteins with molecular sizes ranging from 10 to 33 kDa. Fractions containing proteins with molecular weights of approximately 21, 24, 28 and 32 kDa were identified as putative growth hormone, prolactin, somatolactin and gonadotropins. These were analyzed further by mass spectrometry (MS) and identified with peptide mass protein fingerprinting. Good yield of highly purified GH was obtained, identified, and found to be biologically stable. Subsequently, it was used for radioactive labeling and as standards in a homologous RIA. Using this assay, the GH was measured in halibut larvae from start-feeding through metamorphosis, showing a stable size-related GH content of the head region. Funded by the EU.
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- Einarsdottir, Ingibjörg, 1951, et al.
(författare)
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The growth hormone – IGF-I system is involved in cranial tissue remodeling in metamorphosing Atlantic halibut larvae
- 2008
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Ingår i: Sixth International Symposium on Fish Endocrinology (6ISFE) Program and Abstract Book.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Atlantic halibut is a large, cold-water flatfish which inhabits the North Atlantic. The pelagic and symmetric larvae undergo metamorphosis as an adaptation to better suit them for a benthic life. Metamorphosis involves many dramatic biological changes including a major reconstruction of the cranium during which the left eye migrates to the right side of the head. The structural driving force of eye migration is assumed to be the growth and migration of the ethmoid plate and the migration of the frontal processes towards the future ocular side, and fibroblast proliferation ventrally to the migrating eye. Metamorphosis is under endocrine control and thyroid hormones are known to be the main regulatory hormones. Data on the role of other growth regulators, including the growth hormone (GH) - insulin-like growth factor I (IGF-I) system, in halibut metamorphosis are sparse. GH content in the head region increases steadily from first feeding throughout the larval phase until post-metamorphosis, while IGF-I content in the body increases until the onset of metamorphosis and decline thereafter. In situ hybridization and immunohistochemistry reveal that mRNA and proteins of the type I GH receptor (GHR), and mRNA of the type II GHR and the IGF-I receptor (IGF-IR) are expressed in fibroblasts in soft tissue between the eyes, frontal bone osteocytes and dorsal cranial chondrocytes during the metamorphic process. In fibroblasts and chondrocytes, the expression appears most intense at the start of metamorphosis (stage 8) and decreases during subsequent developmental stages. IGF-IR expression decreases in frontal bone osteocytes after the completion of metamorphosis (stage 10). The decrease in tissue IGF-I content during metamorphosis, and the localization and change in abundance of GHRs and IGF-IR in head structures undergoing reconstruction, indicate the involvement of the GH-IGF-I system in Atlantic halibut metamorphosis. Acknowledgement: Work financed by the Commission of the European Communities within the project “Arrested development: the molecular and endocrine basis of flatfish metamorphosis” (Q5RS-2002-01192).
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- Hildahl, Jon, 1976, et al.
(författare)
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CHARACTERIZATION OF THE GROWTH HORMONE – INSULIN-LIKE GROWTH FACTOR I SYSTEM DURING ATLANTIC HALIBUT METAMORPHOSIS
- 2006
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Ingår i: 7th International Congress on the Biology of Fish, Book of Abstracts.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The GH-IGF-I system is critical for proper growth and development in fish and thus is likely to play a role in the control of flatfish metamorphosis.. In order to characterize the role of GH and IGF-I in Atlantic halibut development, hormonal content (GH and IGF-I RIA) and receptor gene expression (GHR and IGF-IR QPCR) was assessed during normal and abnormal metamorphosis GH larval head content increases throughout normal metamorphosis in parallel with larval weight. The full-length GH receptor (hhGHRfl) mRNA and IGF-I protein levels change in parallel and in a stage-specific manner, with an increase at the onset of metamorphosis followed by down-regulation. Two isoforms of the IGF-I receptor are regulated differently; isoform one (hhIGF-IR1) mRNA increases from pre-metamorphosis to the post-metamorphic juvenile stage, while isoform 2 (hhIGF-IR2) mRNA is highest at early pre-metamorphosis and decreases prior to the onset of metamorphosis. In larvae experiencing arrested development, mRNA levels for hhGHRfl and hhIGF-IR1 and IGF-I larval content are depressed relative to normal individuals, whereas GH content, hhIGF-IR2 mRNA levels and weight are not changed. Increased hhGHRfl mRNA and IGF-I protein levels at the onset of metamorphosis suggest that tissue sensitivity to GH increases during metamorphosis while tissue sensitivity to IGF-I does not change. The data provide new evidence suggesting that GHR and IGF-IR levels may be of critical importance for metamorphic success in Atlantic halibut. Funded by the EU and FORMAS.
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- Power, DM, et al.
(författare)
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Thyroid hormones in growth and development of fish
- 2001
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Ingår i: COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. - 1532-0456. ; 130:4, s. 447-459
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Tidskriftsartikel (refereegranskat)abstract
- The thyroid hormones (THs), thyroxine (T-4) and triiodothyronine (T-3) are products of the thyroid gland in all vertebrates. Their role in early development and metamorphosis is well established in mammals and amphibians, respectively, and recently several studies in fish have highlighted the importance of THs during flatfish metamorphosis. THs are present in high quantities in fish eggs and are presumably of maternal origin. During embryogenesis the concentration of T-4 and T-3 in the eggs decrease until endogenous production starts. Thyroid hormone receptors (TR) have been isolated from several teleosts and in common with tetrapods two receptor isoforms have been identified, TR alpha and TR beta. Both the receptors are expressed in early embryos and larvae of the Japanese flounder (Paralichthys olivaceus), zebrafish (Danio rerio) and seabream (Sparus aurata) although a different temporal pattern is apparent. The role of THs and TRs in fish embryogenesis, larval development and during metamorphosis will be discussed. (C) 2001 Elsevier Science Inc. All rights reserved.
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- Zhou, A, et al.
(författare)
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Habitual coffee consumption and cognitive function: a Mendelian randomization meta-analysis in up to 415,530 participants
- 2018
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1, s. 7526-
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Tidskriftsartikel (refereegranskat)abstract
- Coffee’s long-term effect on cognitive function remains unclear with studies suggesting both benefits and adverse effects. We used Mendelian randomization to investigate the causal relationship between habitual coffee consumption and cognitive function in mid- to later life. This included up to 415,530 participants and 300,760 coffee drinkers from 10 meta-analysed European ancestry cohorts. In each cohort, composite cognitive scores that capture global cognition and memory were computed using available tests. A genetic score derived using CYP1A1/2 (rs2472297) and AHR (rs6968865) was chosen as a proxy for habitual coffee consumption. Null associations were observed when examining the associations of the genetic score with global and memory cognition (β = −0.0007, 95% C.I. −0.009 to 0.008, P = 0.87; β = −0.001, 95% C.I. −0.005 to 0.002, P = 0.51, respectively), with high consistency between studies (Pheterogeneity > 0.4 for both). Domain specific analyses using available cognitive measures in the UK Biobank also did not support effects by habitual coffee intake for reaction time, pairs matching, reasoning or prospective memory (P ≥ 0.05 for all). Despite the power to detect very small effects, our meta-analysis provided no evidence for causal long-term effects of habitual coffee consumption on global cognition or memory.
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