1. Multilevel toxicity assessment of polypropylene microplastics and pyrene on mussels : DNA damage, oxidative stress, and physiological effectsTatjana Mijošek Pavin, Margareta Kračun-Kolarević, Stoimir Kolarević, Tatjana Simčič, Rajko Martinović, Oliver Bajt, Gabriela Kalčíková, Andreja Ramšak, 2026, original scientific article Abstract: Despite extensive research on microplastic pollution, combined biological effects of microplastics and associated pollutants on marine invertebrates remain unclear. We present an integrative assessment of polypropylene (PP) and pyrene, individually and in co-exposure, in mussel Mytilus galloprovincialis. Mussels were exposed to 1 mg L−1 PP (~40 μm) and 50 μg L−1 of pyrene for 7 and 14 days, representing a scenario relevant to highly polluted coastal areas. DNA damage increased significantly in mussels exposed to pyrene or PP alone, but remained at control levels under combined exposure, suggesting an interaction that may reduce genotoxic potential. Lipid peroxidation remained stable across treatments, despite significant changes in antioxidant enzymes. Catalase activity increased in pyrene and pyrene + PP treatments, with tissue-specific trends, indicating enhanced antioxidant protection. Glutathione S-transferase activity was stable in digestive glands but significantly inhibited in gills after seven days under PP exposure. ETS activity increased in pyrene-containing treatments after 14 days, reflecting elevated metabolic demand after prolonged exposure. Respiration rate declined under PP exposure. Heart rate recovery time after the hyposalinity test was the slowest in the pyrene + PP group, indicating compromised physiological resilience. These findings reveal interactive, tissue- and biomarker-specific effects of PP and pyrene. Their combination suggested attenuation of genotoxicity but enhanced physiological stress responses, highlighting the complexity of pollutant interactions and importance of evaluating multiple biomarkers, tissues and pollutants. Presented data provide the first ever biomarker-based evaluation of PP and pyrene co-exposure, offering novel insights into microplastic-pollutant interactions and potential ecological consequences for marine invertebrates. Keywords: mussels, microplastics, PAHs, multi-biomarker approach, co-exposure Published in DiRROS: 23.12.2025; Views: 418; Downloads: 79
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2. Irrigation systems as reservoirs of diverse and pathogenic Pseudomonas syringae strains endangering crop healthMarina Anteljević, Iva Rosić, Olja Medić, Tamara Ranković, Karolina Sunjog, Margareta Kračun-Kolarević, Stoimir Kolarević, Tanja Dreo, Aleksander Benčič, Tanja Berić, 2025, original scientific article Abstract: Pseudomonas syringae (Psy) is a widely distributed bacterial species complex primarily recognized as a foliar pathogen but also inhabits diverse environments, including water habitats, where strains closely related to agricultural pathogens have been identified. The connection between Psy-caused epidemics and its potential presence in nearby irrigation systems remains underexplored. This study comprehensively examined the Psy complex in the Danube-Tisa-Danube Hydrosystem (DTD) in Serbia, assessing its abundance, phylogenetic diversity, and pathogenic potential. To reduce the reliance on the time-consuming steps of isolation and identification, we developed novel high-specific primers and probes for precise detection of strains belonging to phylogroup 2 within Psy complex. Our results demonstrated that dPCR, coupled with highly specific and sensitive primers, outperformed both traditional plating and qPCR in detecting the Psy complex and phylogroup 2 in irrigation waters, making Psy diagnostics more effective. Phylogenetic analysis indicated high strain diversity within the DTD, identifying phylogroups 1, 2, 7, 12, and 13 and haplotypes linked to strains previously encountered in epidemics on sugar beet in Serbia. Notably, 66.67% of the isolates from the DTD were capable of inducing disease. Phylogroup 2 isolates displayed a broad host range, suggesting that the dissemination of Psy from DTD through irrigation, poses a substantial threat to crop health and agricultural productivity. Keywords: phytopathogen detection, irrigation, qPCR, dPCR Published in DiRROS: 05.09.2025; Views: 375; Downloads: 150
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3. Influence of alkylthio and arylthio derivatives of tert-butylquinone on the induction of DNA damage in a human hepatocellular carcinoma cell line (HepG2)Jelena Djordjević, Stoimir Kolarević, Jovana Jovanović Marić, Margareta Kračun-Kolarević, Bojana Žegura, Alja Štern, Dušan M. Sladić, Irena Novaković, Branka Vuković-Gačić, 2024, original scientific article Abstract: The aim of this study was to investigate the effects of tert-butylquinone (TBQ) and its alkylthio and arylthio
derivatives on DNA in vitro, using acellular and cellular test systems. Direct interaction with DNA was studied
using the plasmid pUC19. Cytotoxic (MTS assay) and genotoxic (comet assay and γH2AX focus assays) effects,
and their influence on the cell cycle were studied in the HepG2 cell line. Our results show that TBQ and its
derivatives did not directly interact with DNA. The strongest cytotoxic effect on the HepG2 cells was observed for
the derivative 2-tert-butyl-5,6-(ethylenedithio)-1,4-benzoquinone (IC50 64.68 and 55.64 μM at 24-h and 48-h
treatment, respectively). The tested derivatives did not significantly influence the cell cycle distribution in the
exposed cellular populations. However, all derivatives showed a genotoxic activity stronger than that of TBQ in
the comet assay, with 2-tert-butyl-5,6-(ethylenedithio)-1,4-benzoquinone producing the strongest effect. The
same derivative also induced DNA double-strand breaks in the γH2AX focus assay. Keywords: TBQ derivatives, HepG2 cell line, comet assay, γH2AX assay, cell cycle analysis, cytotoxicity Published in DiRROS: 11.07.2024; Views: 1160; Downloads: 710
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