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Povzetek: The sensitivity of marine microalgae to metal contamination, particularly copper (Cu), is well recognized in ecotoxicology, providing key insights into predicting marine pollution impacts. This study examined the combined effects of Cu toxicity and salinity on the diatom Chaetoceros calcitrans under controlled laboratory conditions. Toxicity assays were conducted using two environmentally relevant Cu concentrations (2 and 5 μg L−1) and three salinity levels (33, 36, and 39) over 96 h, with cell responses analyzed via flow cytometry. Specific growth rate (SGR), chlorophyll fluorescence, fatty acid methyl ester (FAME) composition, polyunsaturated aldehydes (PUAs), and reactive oxygen species (ROS) production were evaluated. Results showed that SGR increased from 1.7 d−1 at salinity 33 to 1.9 d−1 at 39, indicating enhanced growth at higher salinity. However, Cu exposure significantly reduced SGR, particularly under 5 μg L−1 Cu at salinity 33, where SGR dropped to 0.86 d−1. ROS levels were highest under the combined low salinity (33) and 5 μg L−1 Cu treatment, suggesting strong oxidative stress. PUA profiles shifted with Cu and salinity, with stress-related compounds such as 2E,4E/Z-decadienal and 2E,4E/Z,7Z-decatrienal increasing at low salinity. Fatty acid analysis revealed marked rises in saturated fatty acids, especially palmitic acid (C16:0) and myristic acid (C14:0), under Cu exposure. In the Cu2/39 treatment, C16:0 reached 1.34 × 104 fmol cell−1 compared to 1.36 × 103 fmol cell−1 in the control. Monounsaturated fatty acids, notably palmitoleic acid (C16:1), also increased, reaching 7. 46 × 103 fmol cell−1 versus 1.71 × 103 fmol cell−1 in the control. Conversely, polyunsaturated fatty acids, including arachidonic acid (C20:4) and eicosapentaenoic acid (C20:5 n-3), decreased significantly following Cu exposure. Overall, elevated salinity mitigated Cu-induced growth inhibition but intensified oxidative and biochemical stress, underscoring the complex, endpoint-specific responses of C. calcitrans to multiple environmental stressors.
Ključne besede: climate change, ecotoxicology, marine diatom, flow cytometry, lipids
Objavljeno v DiRROS: 11.06.2026; Ogledov: 75; Prenosov: 55
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Povzetek: Paragomphus matroka sp. nov. (holotype ♂: Madagascar, taolagnaro district, iaboakoho, Réserve de Ressources Naturelles de la Forêt Naturelle de Tsitongambarika, Ampasy; Lat. -24.57840°, Lon. 47.14493°; 4.xii.2024; to be deposited in RMNH, Leiden), is described as new to science. The new endemic species is known only from the holotype, the paratype deposited in the MNHN, Paris, and an additional specimen deposited in NHRS, Stockholm. It has been recorded from three localities in the eastern part of the island, scattered over a distance of 1,033 km, within the Madagascar Humid Forests ecoregion. despite the pronounced variation in the colour pattern, the three known specimens are interpreted as conspecific based on concordant diagnostic morphological characters, particularly the nearly identical structure of the secondary genitalia and cerci. The new species is related to P. fritillarius (Selys, 1892) and P. sofiae Bernard & daraż, 2026. From these two more brightly coloured, spotted Hooktail species, P. matrokasp. nov. differs in its considerably darker colouration, a reduced pattern of smaller light markings on the synthorax, and clearly different secondary genitalia. The discovery of a new species underlines the need for additional intensive odonatological studies in Madagascar. improving knowledge of species distributions, taxonomy, phenology and ecological requirements is crucial, especially in the context of threat assessments and conservation of endemic odonate fauna.
Ključne besede: dragonflies, endemic, new species, taxonomy, biogeography, Malagasy Region
Objavljeno v DiRROS: 11.06.2026; Ogledov: 48; Prenosov: 36
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Povzetek: The emergence of new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants poses a challenge to current therapies and emphasises the need for targets that are less susceptible to mutation. The SARS-CoV-2 envelope protein (Epro) is a highly conserved viroporin and is of central importance to the viral life cycle, yet it remains underexplored as a therapeutic target. In this study, we have identified and characterised a novel lead candidate (LC) − (S)-N-(2-((1S,3S,5S,7S)-adamantan-2-yl)ethyl)-2-(butylamino)-3-(1H-indol-3-yl)propanamide − for inhibition of the SARS-CoV-2 Epro ion channel using combined in silico and in vitro approaches. Molecular dynamics (MD) simulations showed that LC forms stable complexes at the N-terminal vestibule, with key interactions at GLU8, THR9, THR11, ASN15, and LEU18, and a calculated binding affinity higher than that of the reference compound rimantadine within the applied MD/molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) framework. Results of in vitro experiments indicated that LC inhibits the model coronavirus murine hepatitis virus at late stages of the viral cycle. Activity under co-treatment conditions further suggests a direct virucidal effect or interference with early entry stages; an EC50 of approximately 12 μM was within the same micromolar range as those observed for the reference Epro inhibitors 5-(N,N-hexamethylene)amiloride and rimantadine. Quantitative PCR experiments showed delayed RNA replication in LC-treated infected cells, while light and transmission electron microscopy displayed the reduced release of virions and prevention of cell lysis. These results emphasise the central role of the Epro ion channel in the coronavirus life cycle and present LC as a promising candidate for the further development of novel coronavirus inhibitors.
Ključne besede: SARS-CoV-2 envelope protein, viroporin, ion channel blockers, molecular docking, molecular dynamics simulations, drug discovery, murine hepatitis virus, in vitro
Objavljeno v DiRROS: 11.06.2026; Ogledov: 65; Prenosov: 53
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Povzetek: Iron-oxide magnetic nanoparticles (MNPs) have been extensively investigated as magnetically actuated nanocatalysts for diagnostic and therapeutic applications. However, because wüstite/magnetite/maghemite phases can interconvert, coexisting Fe2+/Fe3+ species may redirect Fenton-like chemistry and generate reactive oxygen species (ROS) profiles that differ from the intended biocatalytic pathway. Here, we investigate monodisperse biphasic FeO@Fe3O4 core-shell MNPs with an average particle size ⟨d⟩ = 9.6(5) nm, and their glucose-coated analogue, combining EPR radical analysis with toxicity testing in a 3D HepG2 hepatic spheroid model. Naked particles exhibited conventional Fenton-like behavior dominated by hydroxyl radicals (⋅OH), whereas glucose coating markedly suppressed ⋅OH while increasing hydroperoxyl radicals (⋅OOH; ≈55 pM at 60 min), demonstrating ligand-controlled rerouting of the radical pathway. TEM mapping across spheroid cross-sections showed preferential MNP accumulation in the outer layer, with most observed events confined to the outer ≈10–15 μm, corresponding to an approximately one-cell-thick rim; sparse deeper events were observed up to ≈30–35 μm. MNPs produced dose- and time-dependent cytotoxicity in HepG2 spheroids, with IC50 values of 29.3 (24 h) and 10.8 (96 h) µg·cm− 2, without evidence of lipid peroxidation or genotoxicity. MDA levels remained unchanged, the comet assay showed no increase in DNA damage, and γH2AX and phospho-H3 (p-H3) positive events were not detected. Our results show that glucose functionalization provides a simple route to modulate radical pathways and define operational windows for redox-active FeO@Fe3O4 nano-reactors in oxidative nanomedicine.
Ključne besede: iron-oxide nanoparticles, Fenton-like catalysis, cytotoxicity, genotoxicity, HepG2 spheroids
Objavljeno v DiRROS: 02.06.2026; Ogledov: 104; Prenosov: 96
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Povzetek: Bodanella lauterborni W.M. Zimmermann and Heribaudiella fluviatilis (Areschoug) Svedelius are members of brown algae (Phaeophyceae) that exclusively inhabit freshwater habitats. Heribaudiella fluviatilis is the most frequently reported freshwater brown alga, widely distributed in the Northern Hemisphere. In contrast, B. lauterborni, one of the rarest algae globally, has been reported in only four glacial Alpine lakes and has not been observed in nature for nearly 50 years. Since 2019, the species has been considered locally extinct at its type locality, and its presence in the other three lakes is also questionable. Here, we report the occurrence of B. lauterborni in three springs on the Vlasina Plateau (Southeast Serbia), being the first finding of the species in Southeast Europe and the fifth discovery globally in environmental conditions not previously described for the species. We also provide detailed data on the morphology, ecology, and biogeography of B. lauterborni and H. fluviatilis. Additionally, we report the non-obligate association Hildenbrandio rivularis-Heribaudielletum fluviatilis discovered in two rivers. Our findings significantly expand the known ecological and geographical range of phaeophytes, highlighting Southeast Europe as a refugium for freshwater Phaeophyceae biodiversity.
Ključne besede: Phaeophyceae, spring, river, lake, crystalline shales, distribution, ecology, morphology, Hildenbrandio rivularis-Heribaudielletum fluviatilis
Objavljeno v DiRROS: 06.05.2026; Ogledov: 159; Prenosov: 121
Celotno besedilo (23,75 MB)
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