Marko Klobučar

Učka Nature Park in northeastern Istria represents an important habitat for herpetofauna, yet knowledge of certain reptile occurrences within the park has been limited. Field surveys conducted in 2024 and 2025 at selected peripheral sites confirmed, for the first time, the presence of three reptile species previously undocumented in the park: the four-lined snake Elaphe quatuorlineata Lacepède, 1789, European glass lizard Pseudopus apodus (Pallas 1775), and Mediterranean house gecko Hemidactylus turcicus (Linnaeus, 1758). These findings expand the known reptile fauna of Učka Nature Park and provide a valuable baseline for future research, monitoring, and conservation efforts.

Posttranslational modifications of immunoglobulins have been a topic of great interest and have been repeatedly reported as a major factor in disease pathology. Cost‐effective, reproducible, and high‐throughput (HTP) isolation of immunoglobulins from human serum is vital for studying the changes in protein structure and the following understanding of disease development. Although there are many methods for the isolation of specific immunoglobulin classes, only a few of them are applicable for isolation of all subtypes and variants. Here, we present the development of a scheme for fast and simultaneous affinity purification of α (A), γ (G), and μ (M) immunoglobulins from human serum through affinity monolith chromatography. Affinity‐based monolithic columns with immobilized protein A, G, or L were used for antibody isolation. Monolithic stationary phases have a high surface accessibility of binding sites, large flow‐through channels, and can be operated at high flow rates, making them the ideal supports for HTP isolation of biopolymers. The presented method can be used for HTP screening of human serum in order to simultaneously isolate all three above‐mentioned immunoglobulins and determine their concentration and changes in their glycosylation pattern as potential prognostic and diagnostic disease biomarkers.

Objectives The aim of this study was to examine molecular alterations on the protein level in lesions of oral lichen planus (OLP), oral squamous cell carcinoma (OSCC) and healthy mucosa. Materials and methods Global protein profiling methods based on liquid chromatography coupled to mass spectrometry (LC-MS) were used, with a special emphasis on evaluation of deregulated extracellular matrix molecules expression, as well as on analyses of IG2F and IGFR2 expression in healthy mucosa, OLP and OSCC tissues by comparative semi-quantitative immunohistochemistry. Results Mass spectrometry-based proteomics profiling of healthy mucosa, OLP and OSCC tissues (and accompanied histologically unaltered tissues, respectively) identified 55 extracellular matrix proteins. Twenty among identified proteins were common to all groups of samples. Expression of small leucine-rich extracellular matrix proteoglycans lumican and biglycan was found both in OSCC and OLP and they were validated by Western blot analysis as putative biomarkers. A significant increase (p < 0.05) of biglycan expression in OLP-AT group was determined in comparison with OLP-T group, while lumican showed significant up-regulation (p < 0.05) in OLP-T and OSCC-T groups vs. adjacent and control tissue groups. Biglycan expression was only determined in OSCC-AT group. Immunohistochemical analysis of IGF2 and IG2FR expression revealed no significant difference among groups of samples. Conclusion/clinical relevance Biglycan and lumican were identified as important pathogenesis biomarkers of OLP that point to its malignant potential.

A series of novel N-acyclic uracil analogs with linear, branched, aromatic, and cyclopropyl-alkynyl as well as heteroaryl moieties at C-5 were prepared using palladium catalyzed Sonogashira and Stille cross-coupling and evaluated against malignant tumor cell lines. C-5-Furan-2-yl uracil derivative 6 was shown to be more potent against MCF-7 than the reference drug 5-fluorouracil (5-FU), while C-5-alkynyl uracil derivatives 9c and 9e exhibited antibreast cancer activities comparable to 5-FU. Selected compounds induced cell death, partially due to apoptosis, of MCF-7 breast cancer cells. Abrogation of acid ceramidase (ASAH1) expression of 9c and 9e indicated that these compounds could perturb ASAH1-mediated sphingolipid signaling. The selective activity of 9c and 9e against breast cancer cells via the ASAH1-mediated signaling, as a molecular target, might have a great advantage for potential future therapeutic use.

We report here on the synthesis and in vitro anti-tumor effects of a series of novel 1,2,4-triazole (compounds 3–6), 4,5-dicyanoimidazole (compound 7), and purine (compounds 8–13) coumarin derivatives and their acyclic nucleoside analogues 14–18. Structures of novel compounds 3–18 were deduced from their ¹H- and ¹³C-NMR and corresponding mass spectra. Results of anti-proliferative assays performed on a panel of selected human tumor cell lines revealed that compound 6 had moderate cytostatic activity against the HeLa cell line (IC₅₀ = 35 µM), whereas compound 10 showed moderate activity against the HeLa (IC₅₀ = 33 µM), HepG2 (IC₅₀ = 25 µM) and SW620 (IC₅₀ = 35 µM) cell lines. These compounds showed no cytotoxic effects on normal (diploid) human fibroblasts.