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- Håkansson, H., et al.
(författare)
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In vivo and in vitro toxicity of fractionated fish lipids, with particular regard to their content of chlorinated organic compounds
- 1991
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Ingår i: Pharmacology and Toxicology. - : Wiley. - 0901-9928 .- 1600-0773. ; 69:6, s. 459-471
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Tidskriftsartikel (refereegranskat)abstract
- Six different lipid matrices (the intact lipid (IL), four lipid fractions with different polarity, and the free fatty acids (FFAs) obtained by hydrolysis of the triacylglycerol (TAG) containing fraction) were obtained from salmon (Salmo salar) and eel (Anguilla anguilla), each collected at a contaminated and a comparatively uncontaminated catch site along the coast of Scandinavia. The lipid matrices were studied in toxicological test systems representing various biological functions of different organ systems from several species and trophic levels. The results were evaluated with particular respect to the concentrations of extractable organically bound chlorine (EOCl) in the matrices tested. In some test systems, the specimens with a higher EOCl concentration appeared to be more toxic. For example, the TAG containing fraction (F2) from Idefjord eel, having a higher EOCl content than F2 from Oslofjord eel, reduced the number and hatchability of eggs laid by zebrafish. Both IL and F2 of Idefjord eel increased mortality and reduced the oxygen/nitrogen-ratio in blue mussels. Non-polar compounds (F1) from Bothnian Sea salmon induced 7-ethoxyresurofin O-deethylase (EROD) activity in rainbow trout hepatocytes, whereas F1 from Senja salmon did not. F1 from Bothnian Sea salmon also reduced the number of T-cells in foetal mouse thymus anlagen in vitro compared with the cell number in anlagen exposed to F1 from Senja salmon. A positive correlation between EOCl concentration and test response was found for EROD activity in rainbow trout hepatocytes and for ATP-leakage in Erlich ascites tumour cells when testing the phospolipid containing fraction (F4). However, in most test systems the fish oils, irrespective of EOCl content, were of low toxicity, and the observed effects need to be verified in future studies.
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| 2. |
- Bohm, S., et al.
(författare)
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Cooperating nonconsensus cAMP-responsive elements are mediators of adrenocorticotropin-induced VL30 transcription in steroidogenic adrenal cells
- 1993
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Ingår i: Journal of Biological Chemistry. - : American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 268:6, s. 3952-3963
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Tidskriftsartikel (refereegranskat)abstract
- Pituitary-derived trophic hormones regulate cell-type-specific expression of VL30 retrotransposons in tissues that are engaged in steroidogenesis. We show that adrenocorticotropic hormone and forskolin induced VL30 transcription in the steroidogenic adrenal cell line Y1 and that the transcriptional activation was cell type- and protein kinase A-dependent. Three novel cAMP-responsive elements (CREs), within the VL30 long terminal repeat, were identified and shown to activate transcription synergistically when templates bearing multiple sites were compared with templates bearing a single site. This type of regulation was evident only in forskolin-treated cells, and the response elements were found to be inactive as mediators of constitutive transcription. In vitro binding analyses indicated that a consensus CRE and the nonconsensus VL30 CREs differ with respect to binding affinity and specificity to a number of nuclear factors that were identified to be related to proteins within the CREB, Jun, and C/EBP families of transcription factors. The relatively low affinity and/or a restricted binding specificity of the VL30 CREs made it possible to detect forskolin-induced binding of CREB- and Jun-related proteins to these sequences. We suggest that cAMP-induced transcription, specific for steroidogenic cells, can be mediated by a novel type of nonconsensus CREs and that the mechanism for this type of gene regulation is distinct from that mediated through a consensus CRE. We also report the identification of a novel factor, distinct from previously characterized CRE-binding proteins, that constitutively binds to the identified CREs.
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| 5. |
- Garcia-Guzman, M, et al.
(författare)
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Characterization of recombinant human P2X4 receptor reveals pharmacological differences to the rat homologue.
- 1997
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Ingår i: Molecular Pharmacology. - 0026-895X .- 1521-0111. ; 51:1, s. 109-18
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Tidskriftsartikel (refereegranskat)abstract
- We isolated a cDNA from human brain encoding a purinergic receptor that shows a high degree of homology to the rat P2X4 receptor (87% identity). By fluorescence in situ hybridization, the human P2X4 gene has been mapped to region q24.32 of chromosome 12. Tissue distribution analysis of human P2X4 transcripts demonstrates a broad expression pattern in that the mRNA was detected not only in brain but also in all tissues tested. Heterologous expression of the human P2X4 receptor in Xenopus laevis oocytes and human embryonic kidney 293 cells evoked an ATP-activated channel. Simultaneous whole-cell current and Fura-2 fluorescence measurements in human embronic kidney 293 cells transfected with human P2X4 cDNA allowed us to determine the fraction of the current carried by Ca2: this was approximately 8%, demonstrating a high Ca2+ permeability. Low extracellular Zn2+ concentrations (5-10 microM) increase the apparent gating efficiency of human P2X4 by ATP without affecting the maximal response. However, raising the concentration of the divalent cation (> 100 microM) inhibits the ATP-evoked current in a non-voltage-dependent manner. The human P2X4 receptor displays a very similar agonist potency profile to that of rat P2X4 (ATP > > 2-methylthio-ATP > or = CTP > alpha, beta-methylene-ATP > dATP) but has a notably higher sensitivity for the antagonists suramin, pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid, and bromphenol blue. Chimeric constructs between human and rat isoforms as well as single-point mutations were engineered to map the regions responsible for the different sensitivity to suramin and pyridoxal-phosphate-6-azophenyl-2'4'-disulfonic acid.
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| 8. |
- AliRiahi, M, et al.
(författare)
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Three-dimensional image of the Moho undulations beneath the Gulf of Bothnia using wide-angle seismic data
- 1997
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Ingår i: GEOPHYSICAL JOURNAL INTERNATIONAL. - : BLACKWELL SCIENCE LTD. - 0956-540X. ; 129:2, s. 461-471
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The BABEL marine seismic experiment has been carried out to investigate the lithospheric structure and antecedent tectonic signatures of the Baltic Shield, including the Archaean-Proterozoic collisional structure in the northern part of the Gulf of Bothni
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