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| 2. |
- Lundqvist, Johan, et al.
(författare)
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Microcystins activate nuclear factor erythroid 2-related factor 2 (Nrf2) in human liver cells in vitro - Implications for an oxidative stress induction by microcystins
- 2017
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101 .- 1879-3150. ; 126, s. 47-50
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Tidskriftsartikel (refereegranskat)abstract
- Microcystins, a potential threat to drinking water quality, are hepatotoxic but it has remained unclear if microcystins induce oxidative stress. We investigated if four microcystins could activate the Nrf2 pathway, a regulator of oxidative stress response. Nrf2 activity was significantly increased by microcystin-LR and-RR at 10 mu M, by microcystin-LY at 3 mu M, by [D-Asp3]-LR and by microcystin-LR at 1 mu M. Our results lend support to the suggestion that microcystins may induce oxidative stress response. (C) 2016 Elsevier Ltd. All rights reserved.
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| 3. |
- Malina, Tamás, et al.
(författare)
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Individual variability of venom from the European adder (Vipera berus berus) from one locality in Eastern Hungary
- 2017
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101 .- 1879-3150. ; 135, s. 59-70
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Tidskriftsartikel (refereegranskat)abstract
- We have revealed intra-population variability among venom samples from several individual European adders (Vipera berus berus) within a defined population in Eastern Hungary. Individual differences in venom pattern were noticed, both gender-specific and age-related, by one-dimensional electrophoresis. Gelatin zymography demonstrated that these individual venoms have different degradation profiles indicating varying protease activity in the specimens from adders of different ages and genders. Some specimens shared a conserved region of substrate degradation, while others had lower or extremely low protease activity. Phospholipase A(2) activity of venoms was similar but not identical. Interspecimen diversity of the venom phospholipase A(2)-spectra (based on the components' molecular masses) was detected by MALDI-TOF MS. The lethal toxicity of venoms (LD50) also showed differences among individual snakes. Extracted venom samples had varying neuromuscular paralysing effect on chick biventer cervicis nerve-muscle preparations. The paralysing effect of venom was lost when calcium in the physiological salt solution was replaced by strontium; indicating that the block of twitch responses to nerve stimulation is associated with the activity of a phospholipase-dependent neurotoxin. In contrast to the studied V.b. berus venoms from different geographical regions so far, this is the first V.b berus population discovered to have predominantly neurotoxic neuromuscular activity. The relevance of varying venom yields is also discussed. This study demonstrates that individual venom variation among V.b. berus living in particular area of Eastern Hungary might contribute to a wider range of clinical manifestations of V.b. hems envenoming than elsewhere in Europe.
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| 4. |
- Rosén, Johan, et al.
(författare)
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A new method for analysis of underivatized free beta-methylamino-alanine : Validation and method comparison
- 2016
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101 .- 1879-3150. ; 121, s. 105-108
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Tidskriftsartikel (refereegranskat)abstract
- A new method was developed for analysis of free beta-Methylamino-alanine (BMAA) in biological matrices. The method is based on direct analysis of the underivatized molecule, using an amide column for separation by Hydrophilic Interaction Liquid Chromatography (HILIC) and detection by tandem mass spectrometry (MS/MS) using a deuterium labeled internal standard. The use of Ultra-High Performance Liquid Chromatography (UHPLC) combined with MS/MS detection allowed for high chromatographic resolution and a low limit of detection (0.025 mu g/g wet weight (ww) in mussels). The method was validated by analyzing spiked blank mussels from the Baltic Sea (0.15-4.4 mu g/g (ww), trueness 99%-105%, RSD 2%-8%). An inter-laboratory comparative analysis of extracts of mussel was performed. The mussels were extracted according to an established protocol for analysis of free BMAA, and the extracts were then analyzed in parallel by the new method and a validated procedure based on detection of BMAA derivatized with dansyl chloride. Both methods detected BMAA in similar concentrations. Thus, derivatization with dansyl chloride did not influence the results compared to direct detection. The new method presents an alternative to the commonly applied derivatization step, and is proved through validation and method comparison to reliably identify and quantify free BMAA at low concentration levels.
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| 5. |
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| 6. |
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| 7. |
- Turner, Andrew D., et al.
(författare)
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Assessing the presence of marine toxins in bivalve molluscs from southwest India
- 2017
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101 .- 1879-3150. ; 140, s. 147-156
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 Elsevier Ltd The south west coast of India has been showing a steady increase in shellfish cultivation both for local consumption and fishery export, over recent years. Perna viridis and Crassostrea madrasensis are two species of bivalve molluscs which grow in some selected regions of southern Karnataka, close to the city of Mangalore. In the early 1980s, shellfish consumers in the region were affected by intoxication from Paralytic Shellfish Poison present in local bivalves (clams and oysters) resulting in hospitalisation of many, including one fatality. Since then, there have been no further reports of serious shellfish intoxication and there is little awareness of the risks from natural toxins and no routine monitoring programme in place to protect shellfish consumers. This study presents the findings from the first ever systematic assessment of the presence of marine toxins in mussels and oysters grown in four different shellfish harvesting areas in the region. Shellfish were collected and subjected to analysis for ASP, PSP and lipophilic toxins, as well as a suite of non-EU regulated toxins such as tetrodotoxin and selected cyclic imines. Results revealed the presence of low levels of PSP toxins in oysters throughout the study period. Overall, total toxicities reached a maximum of 10% of the EU regulatory limit of 800 μg STX eq/kg. Toxin profiles were similar to those reported from the 1980 outbreak. No evidence was found for significant levels of ASP and lipophilic toxins, although some cyclic imines were detected, including gymnodimine. The results indicated that the risk to shellfish consumers during this specific study period would have been low. However, with historical evidence for extremely high levels of PSP toxins in molluscs, there is a strong need for routine surveillance of shellfish production areas for marine toxins, in order to mitigate against human health impacts resulting from unexpected harmful algal blooms, with potentially devastating socio-economic consequences.
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| 8. |
- Yang, Lei, et al.
(författare)
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Gene expression profiles and molecular mechanism of cultured human chondrocytes' exposure to T-2 toxin and deoxynivalenol
- 2017
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Ingår i: Toxicon. - Amsterdam : Elsevier. - 0041-0101 .- 1879-3150. ; 140, s. 38-44
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Tidskriftsartikel (refereegranskat)abstract
- T-2 toxin and deoxynivalenol (DON) are secondary metabolites produced by Fusarium fungi and are commonly found on food and feed. Although T-2 toxin and DON have been suggested as the etiology of Kashin-Beck disease (KBD), an endemic osteochondropathy, little is known about the mechanism when human chondrocytes are exposed to T-2 toxin and DON. The purpose of this study is to identify the gene expression differences and underlying molecular changes modulated by T-2 toxin and DON in vitro in human chondrocytes. After the experiments of cell viability, the gene expression profiles were analyzed in cells that were treated with 0.01 μg/ml T-2 toxin and 1.0 μg/ml DON for 72 h by Affymetrix Human Gene Chip. The array results showed that 882 and 2118 genes were differentially expressed for T-2 toxin and DON exposure, respectively. Enrichment analysis revealed that diverse cellular processes including DNA damage, cell cycle regulation and metabolism of extracellular matrix were affected when human chondrocytes were exposed to T-2 toxin and DON. These results demonstrate the gene expression differences and molecular mechanism of cultured human chondrocytes exposure to T-2 toxin and DON, and provide a new insight into future research in the etiology of KBD.
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| 9. |
- Bhattacharjee, Payel, 1984, et al.
(författare)
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Aristolochic acid and its derivatives as inhibitors of snake venom L-amino acid oxidase
- 2017
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101. ; 138, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- Snake venom L-amino acid oxidase (LAAO) exerts toxicity by inducing hemorrhage, pneumorrhagia, pulmonary edema, cardiac edema, liver cell necrosis etc. Being well conserved, inhibitors of the enzyme may be synthesized using the template of the substrate, substrate binding site and features of the catalytic site of the enzyme. Previous findings showed that aristolochic acid (AA), a major constituent of Aristolochia indica, inhibits Russell's viper venom LAAO enzyme activity since, AA interacts with DNA and causes genotoxicity, derivatives of this compound were synthesized by replacing the nitro group to reduce toxicity while retaining the inhibitory potency. The interactions of AA and its derivatives with LAAO were followed by inhibition kinetics and surface plasmon resonance. Similar interactions with DNA were followed by absorption spectroscopy and atomic force microscopy. LAAO-induced cytotoxicity was evaluated by generation of reactive oxygen species (ROS), cell viability assays, confocal and epifluorescence microscopy. The hydroxyl (AA-OH) and chloro (AA-C1) derivatives acted as inhibitors of LAAO but did not interact with DNA. The derivatives significantly reduced LAAO-induced ROS generation and cytotoxicity in human embryonic kidney (HER 293) and hepatoma (HepG2) cell lines. Confocal images indicated that AA, AA-OH and AA-Cl interfered with the binding of LAAO to the cell membrane. AA-OH and AA-CI significantly inhibited LAAO activity and reduced LAAO-induced cytotoxicity. (C) 2017 Elsevier Ltd. All rights reserved.
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| 10. |
- Wang, C., et al.
(författare)
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The toxic effects of microcystin-LR on mouse lungs and alveolar type II epithelial cells
- 2016
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101. ; 115, s. 81-88
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Microcystin-leucine arginine (MC-LR) is produced by cyanobacteria and can accumulate in lungs through blood circulation. However, the effect of MC-LR on lung remains unclear. In this study, we investigated the chronic, low-dose effect of MC-LR on mouse lung tissues and the influence of MC-LR on mouse alveolar type II epithelial cells (ATII cells). Methods: MC-LR was orally administered to mice at 0, 1, 10, and 40 mu g/L for 6 consecutive months and mouse lungs were obtained for histopathological and immunoblot analysis. ATII cells were cultured in various concentrations of MC-LR (0, 0.5, 5, 50, 500 nmol/L) for indicated time and the cell viability and proteins change were tested. Results: Our study revealed that the chronic, low-dose MC-LR exposure induced alveolar collapse and lung cell apoptosis as well as the breach of cell junction integrity. Furthermore, following treatment with MC-LR, ATII cells could uptake MC-LR, resulting in apoptosis and disruption of cell junction integrity. Conclusions: These data support the toxic potential of low-dose MC-LR in rendering chronic injury to lung tissues.
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