| 1. |
- Mayer, Gregory D., et al.
(author)
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Activation of the rainbow trout metallothionein-A promoter by silver and zinc
- 2003
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In: Comparative Biochemistry and Physiology - Part B. - 1096-4959 .- 1879-1107. ; 134:1, s. 181-188
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Journal article (peer-reviewed)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.
(author)
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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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In: Comparative Biochemistry and Physiology - Part B. - 1096-4959 .- 1879-1107. ; 133, s. 119-
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Journal article (peer-reviewed)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.
(author)
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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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In: Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology. - : Elsevier BV. - 1096-4959 .- 1879-1107. ; 175, s. 1-8
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Journal article (peer-reviewed)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. |
- Dave, Göran, 1945, et al.
(author)
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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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In: Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology. - 1096-4959 .- 1879-1107. ; 53:4, s. 509-515
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Journal article (peer-reviewed)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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| 5. |
- Dave, Göran, 1945, et al.
(author)
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Metabolic and hematological studies on the yellow and silver phases of the European eel, Anguilla anguilla L.—II. Fatty acid composition
- 1974
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In: Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology. - 1096-4959 .- 1879-1107. ; 43:3, s. 583-591
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Journal article (peer-reviewed)abstract
- 1.1. Fatty acid composition in liver, muscle and gonads of yellow and silver phases of the European eel (Anguilla anguilla L.) was determined by gas-liquid chromatography (GLC). 2.2. Significantly higher amounts of were found in the gonads of silver eels compared to yellow eels. 3.3. In the gonads of silver eels the amounts of the unsaturated acids, palmitoleic (16:1), oleic (18:1) and linoleic (18:2), were significantly higher while the amount of palmitic acid (16:0) was significantly lower. 4.4. In the liver the amount of stearic (18:0) and arachidonic acid (20:4) was significantly lower, while the amount of linoleic acid (18:2) was significantly higher in the silver phase.
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| 6. |
- Fällmar, Helena, 1980-, et al.
(author)
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Neuropeptide Y/peptide YY receptor Y2 duplicate in zebrafish with unique introns displays distinct peptide binding properties
- 2011
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In: Comparative Biochemistry and Physiology - Part B. - : Elsevier BV. - 1096-4959 .- 1879-1107. ; 160:4, s. 166-173
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Journal article (other academic/artistic)abstract
- The neuropeptide Y-family peptides and receptors are involved in a broad range of functions including appetite regulation. Both the peptide genes and the receptor genes are known to have duplicated in early vertebrate evolution. The ancestral jawed vertebrate had 7 NPY receptors but the number varies between 4 and 7 in extant vertebrates. Herein we describe the identification of an additional NPY receptor in two fish species, zebrafish and medaka. They cluster together with the Y2 receptors in phylogenetic analyses and seem to be orthologous to each other that is why we have named them Y2-2. Their genes differ from Y2 in having introns in the coding region. Binding studies with zebrafish Y2-2 receptors show that the three endogenous peptides NPY, PYYa and PYYb have similar affinities, 0.15-0.66nM. This is in contrast to the Y2 receptor where they differed considerably from one another. N-terminally truncated NPY binds poorly and the Y2 antagonist BIIE0246 binds well to Y2-2, results that are reversed in comparison to Y2. Zebrafish Y2-2 mRNA was detected by PCR in the intestine and the eye, but not in the brain. In conclusion, we have found a novel Y2-like NPY/PYY receptor that probably arose in early teleost fish evolution.
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| 7. |
- Gaudry, Michael J., et al.
(author)
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Comparative functional analyses of UCP1 to unravel evolution, ecophysiology and mechanisms of mammalian thermogenesis
- 2021
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In: Comparative Biochemistry and Physiology - Part B. - : Elsevier BV. - 1096-4959 .- 1879-1107. ; 255
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Journal article (peer-reviewed)abstract
- Brown adipose tissue (BAT), present in many placental mammals, provides adaptive nonshivering thermogenesis (NST) for body temperature regulation and has facilitated survival in diverse thermal niches on our planet. Intriguingly, several key details on the molecular mechanisms of NST and their potential ecophysiological adaptations are still unknown. Comparative studies at the whole animal level are unpragmatic, due to the diversity and complexity of thermoregulation among different species. We propose that the molecular evolution of mitochondrial uncoupling protein 1 (UCP1), a central component for BAT thermogenesis, represents a powerful opportunity to unravel key questions of mammalian thermoregulation. Comparative analysis of UCP1 may elucidate how its thermogenic function arose, how environmental selection has shaped protein function to support ecophysiological requirements, and how the enigmatic molecular mechanism of proton leak is governed. Several approaches for the assessment of UCP1 function in vitro have been introduced over the years. For comparative characterization of UCP1, we put forward the overexpression of UCP1 orthologues and mutated variants in a mammalian cell system as a primary strategy and discuss advantageous aspects in contrast to other experimental systems. In turn, we suggest how remaining experimental caveats can be solved by complimentary test systems before physiological consolidation in the animal model. Furthermore, we highlight the appropriate bioenergetic techniques to perform the functional analyses on UCP1. The comparative characterizations of diverse UCP1 variants may enable key insights into open questions surrounding the molecular basis of NST.
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| 8. |
- Håkansson, Katarina, et al.
(author)
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Mouse and rat cystatin C: Escherichia coli production, characterization and tissue distribution
- 1996
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In: Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology. - : Elsevier BV. - 1879-1107 .- 1096-4959. ; 114:3, s. 303-311
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Journal article (peer-reviewed)abstract
- Recombinant mouse (Mus musculus) and rat (Rattus norvegicus) cystatin C were produced by expression in Escherichia coli, isolated and functionally characterized. The mouse and rat inhibitors were both fully active in titrations of papain. Determination of equilibrium constants for dissociation (Ki) for their complexes with the target proteinase, cathepsin B, produced values not largely different from that for human cystatin C (Ki 0.07-0.13 nM). Rabbit antisera against mouse and rat cystatin C were produced and used for improved affinity purification of the recombinant inhibitors. Affinity purified immunoglobulins isolated from the antiserum against mouse cystatin C were used for construction of a sensitive enzyme-linked immunosorbent assay. The assay was used to demonstrate a high degree of immunological cross-reactivity between mouse and rat cystatin C and could be used for cystatin C quantification in mouse and rat tissue homogenates. All tissues analyzed contained cystatin C, with a relative content very similar to that of human tissues. For all species, brain tissue contained the highest cystatin C amounts and liver the lowest, whereas kidney, spleen and muscle tissues were intermediate in content. In the mouse, a notable high cystatin C content in parotid gland tissue was observed. The high degree of similarity in distribution pattern and functional properties for mouse, rat and human cystatin C indicates that a murine model should be relevant for studies of the human disease, hereditary cystatin C amyloid angiopathy.
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| 9. |
- Jönsson, K. Ingemar, 1959-, et al.
(author)
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Induction of Hsp70 by desiccation, ionising radiation and heat-shock in the eutardigrade Richtersius coronifer
- 2007
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In: Comparative Biochemistry and Physiology - Part B. - 1096-4959 .- 1879-1107. - 1096-4959 ; 146:4, s. 456-460
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Journal article (peer-reviewed)abstract
- The physiology and biochemistry behind the extreme tolerance to desiccation shown by the so-called anhydrobiotic animals represents an exciting challenge to biology. The current knowledge suggests that both carbohydrates and proteins are often involved in protecting the dry cell from damage, or in the repair of induced damage. Tardigrades belong to the most desiccation-tolerant multicellular organisms, but very little research has been reported on the biochemistry behind desiccation tolerance in this group. We quantified the induction of the heat-shock protein Hsp70, a very wide-spread stress protein, in response to desiccation, ionising radiation, and heating, in the anhydrobiotic tardigrade Richtersius coronifer using an immuno-westemblot method. Elevated levels of Hsp70 were recorded after treatment of both heat and ionising radiation, and also in rehydrated tardigrades after a period of desiccation. In contrast, tardigrades in the desiccated (dry) state had reduced Hsp70 levels compared to the non-treated control group. Our results suggest that Hsp70 may be involved in the physiological and biochemical system underlying desiccation (and radiation) tolerance in tardigrades, and that its role may be connected to repair processes after desiccation rather than to biochemical stabilization in the dry state.
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| 10. |
- Lewander, Kerstin, et al.
(author)
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Metabolic and hematological studies on the yellow and silver phases of the European eel, Anguilla anguilla L.—I. Carbohydrate, lipid, protein and inorganic ion metabolism
- 1974
-
In: Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology. - 1096-4959 .- 1879-1107. ; 47:3, s. 571-581
-
Journal article (peer-reviewed)abstract
- 1.1. The contents of different metabolites were determined in white and dark muscle, liver, blood and gonads of the yellow and silver phases of the European eel, Anguilla anguilla L. 2.2. The plasma cortisol level in the silver eels was lower than in the yellow eels. 3.3. The silver eels also showed an increased redistribution and utilization of fat as well as a changed carbohydrate and protein metabolism. 4.4. An enhanced content of dark muscle was found in the silver eels, indicating an adaptation for spawning migration.
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