| 1. |
- Donis, Daphne, et al.
(författare)
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Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer
- 2021
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Ingår i: Limnology and Oceanography. - : John Wiley & Sons. - 0024-3590 .- 1939-5590. ; 66:12, s. 4314-4333
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Tidskriftsartikel (refereegranskat)abstract
- To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L-1), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long-term average, during a summer heatwave was the highest (+4 degrees C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient-rich lakes than nutrient concentrations and surface temperature.
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| 2. |
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| 3. |
- Grenegård, Magnus, 1963-, et al.
(författare)
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The cardioprotective, anti-inflammatory and antithrombotic piperazinyl-purine analogue MK177 is a bifunctional drug with promising therapeutic potential
- 2023
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Ingår i: British Journal of Pharmacology. - : Macmillan Publishers Ltd.. - 0007-1188 .- 1476-5381. ; 180:Suppl. 1, s. 158-159
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Nitrate ester bearing 6-piperazinyl-purine analogues (denoted MK drugs) are cardioprotective in infarction animal models and act as inhibitors of Janus kinase (JAK) and Rho-associated kinase (ROCK) [1-3]. Despite the presence of nitrate ester moiety, the MK drugs do not release nitric oxide (NO).Methods: We utilized organic chemistry platforms to design a dinitrate ester derivative denoted MK177, cell-free and cellular assays to elucidate antithrom-botic and anti-ischemic mechanisms. Furthermore, we also used tissue models to analyze vasodilation, and animal models to evaluate drug activities in vivo.Results: In anesthetized pigs, intravenous infusion of MK177 produced“nitroglycerin-like”effects on vital parameters. Analysis of exhaled air confirmed release of NO. MK177 caused concentration-dependent relaxation of iliac arteries (87±6.8 % relaxation of precontracted arteries, mean value ±SD, n=5) and this effect was mediated by activation of the NO/cyclic GMP signaling pathway. It is noteworthy that other mononitrate or non-nitrate MKs did not cause NO-induced vasodilation. In cellular model systems, MK177 evoked antithrombotic effects by targeting ROCK in a NO-independent manner. Specifically, MK177 inhibited platelet aggregation induced by collagen (72±12.6 % inhibition of aggregation, mean value±SD, n=7). Western blot analyses confirmed that MK177 reduced ROCK-dependent phosphorylation of myosin phosphatase sub-unit (MYPT-1) in platelets. Finally, kinase screening assay revealed that MK177 concentration-dependently inhibited ROCK and JAK (Kd values around 5μM).Conclusion: We have developed a bifunctional drug molecule, MK177, that acts by NO-dependent and NO-independent mechanisms. MK 177 induced car-diovascular NO effects in vivo and relaxed vessels in vitro. MK177 also prevented blood platelet activation via NO-independent ROCK inhibition. The bifunctional nature of MK177 can be of significance in future management of thrombotic and ischemic disease. Collectively, the novel cardio-protective and bifunctional drug MK177 has promising therapeutic potential.References:1. Koufaki M, Fotopoulou T, Iliodromitis EK, Bibli SI, Zoga A, Kremastinos DT, Andreadou I. Discovery of 6-[4-(6-nitroxyhexanoyl)(piperazin-1-yl)]-9H-purine, as pharmacological post-conditioning agent. Bioorg Med Chem. 2012;20(19):5948-5956. https://doi.org/10.1016/j.bmc.2012.07.0372. Kardeby C, Paramel GV, Pournara D, Fotopoulou T, Sirsjö A, Koufaki M, Fransén K, Grenegård M. A novel purine analogue bearing nitrate ester prevents platelet activation by ROCK activity inhibition. Eur J Pharmacol. 2019;15(857):172428-172434. https://doi.org/10.1016/j.ejphar.2019.1724283. Paramel GV, Lindkvist M, Idosa BA, Sebina LS, Kardeby C, Fotopoulou T, Pournara D, Kritsi E, Ifanti E, Zervou M, Koufaki M, Grenegård M, Fransén K. Novel purine analogues regulate IL-1βrelease via inhibition of JAK activity in human aortic smooth muscle cells. Eur J Pharmacol. 2022;15(929):175128-175135. https://doi.org/10.1016/j.ejphar.2022.175128
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| 4. |
- Mantzouki, Evanthia, et al.
(författare)
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Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins
- 2018
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Ingår i: Toxins. - : MDPI. - 2072-6651. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.
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| 5. |
- Paramel Varghese, Geena, 1985-, et al.
(författare)
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Novel purine analogues regulate IL-1β release via inhibition of JAK activity in human aortic smooth muscle cells
- 2022
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Ingår i: European Journal of Pharmacology. - : Elsevier. - 0014-2999 .- 1879-0712. ; 929
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Tidskriftsartikel (refereegranskat)abstract
- Purine analogues bearing a nitrate ester motif were previously discovered as cardioprotective and anti-inflammatory agents, but the anti-inflammatory mechanism remains to be established. We therefore investigated the anti-inflammatory effect of two purine analogues, MK118 bearing a nitrate ester moiety and the methyl-substituted analogue MK196 in Aortic Smooth Muscle Cells (AoSMCs), with emphasis on IL-1β release. The AoSMCs were stimulated with LPS with or without purine analogue, followed by ELISA, Olink proteomics, Western blot and real time PCR of NLRP3 inflammasome components. Both purine analogues inhibited the release of proteins involved in inflammation, such as TRAIL, CCL4, CSF1 and IL-1β in AoSMCs, as well as intracellular gene and protein expression of IL-1β and NLRP3 inflammasome components. MK196, but not MK118, also inhibited the LPS-induced release of IL-7, CXCL10, PD-L1, FLT3L and CCL20. We also showed that MK118 and possibly MK196 act via inhibition of JAKs. In silico studies showed that the purine moiety is a competent hinge binding motif and that the purine-piperazine scaffold is well accommodated in the lipophilic groove of JAK1-3. Both compounds establish interactions with catalytic amino acids in the active site of JAK1-3 and the terminal nitrate ester of MK118 was revealed as a promising pharmacophore. Our data suggest that MK118 and MK196 inhibit the release of proinflammatory proteins in AoSMCs, and targets JAK1-3 activation. Purine analogues also inhibit the expression of NLRP3 inflammasome genes and proteins and may in the future be evaluated for anti-inflammatory aspects on inflammatory diseases.
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| 6. |
- Christodoulou, Paris, et al.
(författare)
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In Vitro Fermentation of Pleurotus eryngii Mushrooms by Human Fecal Microbiota : Metataxonomic Analysis and Metabolomic Profiling of Fermentation Products
- 2023
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Ingår i: Journal of Fungi. - : MDPI. - 2309-608X. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Edible mushrooms contain biologically active compounds with antioxidant, antimicrobial, immunomodulatory and anticancer properties. The link between their anticancer and immunomodulatory properties with their possible prebiotic activity on gut micro-organisms has been the subject of intense research over the last decade. Lyophilized Pleurotus eryngii (PE) mushrooms, selected due to their strong lactogenic effect and anti-genotoxic, immunomodulatory properties, underwent in vitro static batch fermentation for 24 h by fecal microbiota from eight elderly apparently healthy volunteers (>65 years old). The fermentation-induced changes in fecal microbiota communities were examined using Next Generation Sequencing of the hypervariable regions of the 16S rRNA gene. Primary processing and analysis were conducted using the Ion Reporter Suite. Changes in the global metabolic profile were assessed by 1H NMR spectroscopy, and metabolites were assigned by 2D NMR spectroscopy and the MetaboMiner platform. PLS-DA analysis of both metataxonomic and metabolomic data showed a significant cluster separation of PE fermented samples relative to controls. DEseq2 analysis showed that the abundance of families such as Lactobacillaceae and Bifidobacteriaceae were increased in PE samples. Accordingly, in metabolomics, more than twenty metabolites including SCFAs, essential amino acids, and neurotransmitters discriminate PE samples from the respective controls, further validating the metataxonomic findings.
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