| 1. |
- Mayer, Gregory D., et al.
(författare)
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Activation of the rainbow trout metallothionein-A promoter by silver and zinc
- 2003
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Ingår i: Comparative Biochemistry and Physiology - Part B. - 1096-4959 .- 1879-1107. ; 134:1, s. 181-188
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Tidskriftsartikel (refereegranskat)abstract
- In fish, the synthesis of metallothionein (MT) is increased by a number of heavy metals. The rainbow trout MT-A gene promoter region contains six known metal responsive elements (MREs), that mediate promoter activation by metals. In the present study, two fish cell lines differing in their ability to produce MT, RTG-2 (produce MT protein) and CHSE-214 (produce no detectable MT protein), were used to help elucidate the roles of Zn, Ag and MT in the activation of the MT promoter. The hypothesis tested was that Ag activates the MT-A promoter indirectly by displacing Zn from pre-existing Zn-MT and that this liberated Zn subsequently induces MT synthesis. Both cell lines were transfected with a luciferase reporter gene construct containing the rainbow trout MT-A promoter, exposed to various concentrations of Zn or Ag, and assayed for luciferase activity. CHSE-214 cells showed five times greater production of luciferase than RTG-2 cells when exposed to identical concentrations of Ag. Thus, Ag can likely induce MT transcription without displacing Zn from pre-existing Zn-MT. Furthermore, Ag activated the MT promoter at concentrations 100-fold lower than those required for Zn to initiate transcription, suggesting that zinc displaced from other sites by such low concentrations of Ag would not be sufficient to initiate MT transcription. This interpretation was further supported by radiotracer studies indicating that Ag did not cause a redistribution of 65Zn within either of the two cell types. These combined results indicate that Ag may be a direct inducer of MT.
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| 2. |
- Westermark, Gunilla, 1958-, et al.
(författare)
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Islet amyloid polypeptide is expressed in the pancreatic islet parenchyma of the teleostean fish, Myoxocephalus (cottus) scorpius
- 2002
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Ingår i: Comparative Biochemistry and Physiology - Part B. - 1096-4959 .- 1879-1107. ; 133, s. 119-
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Tidskriftsartikel (refereegranskat)abstract
- The comparative endocrinology of the 37-amino-acid-residue islet amyloid polypeptide (IAPP) is poorly known, possibly due to the fact that available antisera, raised against mammalian IAPP, fail to give immunoreactivity with islet parenchymal cells of non-mammalian vertebrates. Using reverse transcriptase-linked polymerase chain reaction with degenerate primers, IAPP was identified, and its deduced amino-acid sequence partially characterized, in three species of teleostean fish, i.e. Danio rerio (zebrafish), Salmo salar (Atlantic salmon), and Myoxocephalus (cottus) scorpius (daddy sculpin). The daddy sculpin is a species where the histophysiology of the pancreatic islet parenchyma has previously been comprehensively studied. From the deduced amino-acid sequence, a synthetic peptide, corresponding to positions 20-29 of Salmo IAPP, was synthesized. A mouse antiserum to this peptide gave a distinct immunoreactivity with the insulin-producing beta cells of the sculpin Brockmann bodies and salmon endocrine pancreas. Thus, IAPP belongs to the group of peptide hormones expressed by the islet parenchymal cells in both mammals and non-mammalian vertebrates. Salmo salar IAPP(20-29) was found to give rise to amyloid-like fibrils in vitro.
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| 3. |
- Abro, Rani, et al.
(författare)
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Evaluation of chitinolytic activities and membrane integrity in gut tissues of Arctic charr (Salvelinus alpinus) fed fish meal and zygomycete biomass.
- 2014
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Ingår i: Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology. - : Elsevier BV. - 1096-4959 .- 1879-1107. ; 175, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Chitinolytic activity, nutrient uptake and intestinal barrier functions were investigated in gut tissues of Arctic charr (Salvelinus alpinus) fed iso-nitrogenous diets based on fish meal, with or without inclusion of zygomycetes (Rhizopus oryzae). We found that gut tissue of Arctic charr had significant chitinase activity, of both endo- and exo-chitinase iso-forms. Moreover, the distribution pattern along the GI tract of Arctic charr differed between endo-chitinase and exo-chitinase. The endo-chitinase activity in stomach tissue and in the distal intestine was several hundred-fold higher than the exo-chitinase activity in stomach tissue. The greatest exo-chitinase activity was found in the distal intestine. The zygomycete-based diet resulted in higher chitinolytic activity in gut tissue compared to the fish meal-based diet. Disturbed intestinal integrity and increased uptake rate of the amino acid lysine were observed in the distal, but not proximal, intestine of fish fed the zygomycete-based feed.
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| 4. |
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| 5. |
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| 6. |
- Carney Almroth, Bethanie, 1974, et al.
(författare)
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Early-age changes in oxidative stress in brown trout, Salmo trutta
- 2010
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Ingår i: COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY. - 1096-4959. ; 155:4, s. 442-448
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Tidskriftsartikel (refereegranskat)abstract
- Fish are often used as models for studies investigating the ability of xenobiotics to induce oxidative stress, though age or developmental stage of the individuals studied has been given little attention. Oxidative stress in other organisms is associated with aging as well as with periods of rapid growth, which occurs in young brown trout. We measured protein carbonyls, 20S proteosome activity and glutathione (GSH) levels in farmed Salmo trutta in four different age groups from 5 months to 3 years. We found an increase in protein carbonyls and a decrease in 20S proteosome activity in both brain and liver tissues of the fish with increasing size and age. Total GSH levels in liver tissue declined as fish aged and the GSSG:GSH ratio increased. Five month and 1 year old trout were treated with paraquat (PQ) to induce oxidative stress. Five month old fish showed no changes in the measured parameters while 1 year old fish had both an increase in protein carbonylation in liver tissue and a decrease in 20S proteosome activity in brain tissue. These results indicate that oxidative stress biomarkers are affected by age or rapid growth in brown trout, and that individuals of different ages respond differently to oxidative stress induced by PQ.
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| 7. |
- Carney Almroth, Bethanie, 1974, et al.
(författare)
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Oxidative stress and biomarker responses in the Atlantic halibut after long term exposure to elevated CO2 and a range of temperatures
- 2019
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Ingår i: Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology. - : Elsevier BV. - 1096-4959. ; 238
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Tidskriftsartikel (refereegranskat)abstract
- CO2 emissions from human activities are increasing, resulting in greater rates of change in the oceans, exceeding any other event in geological and historical records over the past 300 million years. Oceans are warming and pH levels are decreasing. Marine organisms will need to respond to multiple stressors and the potential consequences of global change-related effects in fish needs to be investigated. Fish are affected by many biotic and abiotic environmental variables, including temperature and CO2 fluctuations, and it is therefore critical to investigate how these variables may affect physiological and biochemical processes. We investigated the effects of elevated CO2 levels (pH of 8.0, which served as a control, or 7.6, which is predicted for the year 2100) combined with exposure to different temperatures (5, 10, 12, 14, 16, and 18 degrees C) in the Atlantic halibut (Hippoglossus hippoglossus) during a three month experiment. Since regulation of reactive oxygen species (ROS) is crucial for physiological processes the focus was on the antioxidant defense system and we assessed the effects on catalytic activities of antioxidant enzymes (SOD, CAT, GR, GST, GPx). In addition we also analyzed effects on cholinesterase enzymes (AChE and BChE), and CYP1A enzyme activities (EROD). The treatments resulted in oxidative stress, and damage was evident in the form of protein carbonyls which were consistently higher in the elevated CO2 -treated fish at all temperatures. Analyses of antioxidant enzymes did not show the same results, suggesting that the exposure to elevated CO2 increased ROS formation but not defences. The antioxidant defense system was insufficient, and the resulting oxidative damage could impact physiological function of the halibut on a cellular level.
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| 8. |
- Cobb, Christopher S., et al.
(författare)
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Angiotensin I-converting enzyme-like activity in tissues from the Atlantic hagfish (Myxine glutinosa) and detection of immunoreactive plasma angiotensins
- 2004
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Ingår i: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology. - : Elsevier BV. - 1096-4959. ; 138,:4, s. 357-364
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Tidskriftsartikel (refereegranskat)abstract
- Using a highly sensitive fluorimetric assay, significant levels of angiotensin I -converting enzyme-like activity (ACELA) were detected in a range of tissues (branchial heart, gill, kidney with associated vasculature and archinephric duct, liver, whole brain and gut) from the Atlantic hagfish (Myxine glutinosa). The highest ACELA occurred in heart and gill (1.8 and 1.5 nmol His–Leu min−1 mg protein−1, respectively). The mammalian angiotensin I-converting enzyme (ACE) inhibitor, captopril, at 10−5 M was a potent inhibitor of the ACELA found in all hagfish tissues. Radioimmunoassay showed that immunoreactive angiotensins (251.8±11.8 pM) were detectable in hagfish plasma. The validity of the assay for measurement of hagfish angiotensins was indicated by the parallelism of the angiotensin II standard curve against serially diluted hagfish plasma. Measurement of immunoreactive plasma angiotensins and detection of significant levels of ACELA in a wide range of tissues gives indirect evidence for the presence of a renin–angiotensin system in hagfishes, the earliest evolved group of craniates
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| 9. |
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| 10. |
- Dave, Göran, 1945, et al.
(författare)
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Metabolic and hematological effects of starvation in the european eel, Anguilla anguilla L.—III. Fatty acid composition
- 1976
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Ingår i: Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology. - 1096-4959 .- 1879-1107. ; 53:4, s. 509-515
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Tidskriftsartikel (refereegranskat)abstract
- 1.1. Fatty acid composition in liver and muscle was studied in the European eel (Anguilla anguilla L.) after 11, 47, 96 and 164 days of starvation during the winter season. 2.2. The changes in muscle were small compared with those in liver. 3.3. In both liver and muscle there was a marked decrease in 14:0.∗ 4.4. In the liver starvation caused a decrease in 16:1, 18:1, 20:1 and/or 18:3 and an increase in 20:4, 20:5, 22:4 and 22:5. 5.5. The observed changes are discussed in relation to differences in distributional pattern among the lipid classes, to α- and β-positional preferences and to environmental temperature.
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