Karolina Dzedulionytė

Silk fibroin offers excellent material properties for a growing range of biomedical applications; however, its potential as an in vitro platform for molecular imaging remains largely unexplored. We established and systematically characterized a modular silk sponge library comprising lipophilic (lanolin, beeswax), amphiphilic (lecithin), and hydrophilic (agarose, gelatin, carrageenan, chitosan) modifications to generate extracellular matrix-like environments with distinct morphological, structural, and physicochemical properties as well as biocompatibility. The modularity of the library enables systematic comparison and fit-for-purpose selection of material compositions, allowing scaffold properties to be tailored to the specific applications. Selected modifications were subsequently integrated into a mechanically robust, perfusable 3D scaffold platform for dynamic molecular imaging. As a proof of concept, non-displaceable binding of six representative PET radiotracers was investigated in a dynamic column-based µ-PET/CT setup. [¹¹C]PIB and [⁶⁸Ga]DOTANOC showed the highest retention in unmodified silk fibroin, whereas the remaining tracers exhibited only minor adsorption. Complementary molecular dynamics simulations and docking-based affinity estimations supported predominantly non-specific interactions with β-sheet-rich silk fibroin domains. Overall, this study establishes a silk sponge library that enables systematic tuning and fit-for-purpose material selection, and translates selected compositions into a perfusable in vitro platform for dynamic radiotracer evaluation, bridging tunable biomaterials with molecular imaging applications.

Parasitic nematodes are a significant concern in human and veterinary medicine as well as agriculture. In this study, we prepared twenty-seven 5-phenyl-1H-indole derivatives bearing various substituents on the phenyl ring and assessed their efficacy against nematodes. Using Caenorhabditis elegans, we selected the most potent compounds and evaluated their toxicity on selected animal and plant-parasitic nematode species. Compounds featuring 4-chloro, 4-fluoro, and 4-trifluoromethoxy groups on the phenyl ring inhibited the motility of exsheathed L3 larvae of Hemonchus contortus while exhibiting limited cytotoxicity in mammalian cell cultures. These compounds showed similar effects against the plant-parasitic nematodes Heterodera schachtii and Ditylenchus destructor, albeit with reduced potency. We propose that the compounds might act as inhibitors of mitochondrial complex II as inferred from molecular modeling, decreased mitochondrial membrane potential, and reduced activity in C. elegans complex II mutants.

This review briefly and systematically overviews C–H and N–H functionalization reactions of pyrazoles, aimed at creating new CC and Cheteroatom bonds on the pyrazole ring. It discusses various strategies, including traditional cross‐coupling reactions that necessitate prefunctionalized pyrazoles as well as direct functionalization reactions, which offer a more efficient approach to obtaining a diverse array of functionalized derivatives in only one step.

Auxins play an important role in plant physiology and are involved in numerous aspects of plant development, such as cell division, elongation and differentiation, fruit development, and phototropic response. In addition, through their antagonistic interaction with cytokinins, auxins play a key role in the regulation of root growth and apical dominance. Thanks to this capacity to determine plant architecture, natural and synthetic auxins have been successfully employed to obtain more economically advantageous plants. The crosstalk between auxins and cytokinins determines plant development and thus is of particular importance in the field of plant micropropagation, where the ratios between these two phytohormones need to be tightly controlled to achieve proper rooting and shoot generation. Previously reported anti-auxin PEO-IAA, which blocks auxin signalling through binding to TIR1 receptor and inhibiting the expression of auxin-responsive genes, has been successfully used to facilitate hemp micropropagation. Herein, we report a set of new PEO-IAA-inspired anti-auxins capable of antagonizing auxin responses in vivo. The capacity of these compounds to bind to the TIR1 receptor was confirmed in vitro by SPR analysis. Using DESI-MSI analysis, we evaluated the uptake and distribution of the compounds at the whole plant level. Finally, we characterized the effect of the compounds on the organogenesis of hemp explants, where they showed to be able to improve beneficial morphological traits, such as the balanced growth of all the produced shoots and enhanced bud proliferation.

A library of pyrazole-based lamellarin O analogues was synthesized from easily accessible 3(5)-aryl-1H-pyrazole-5(3)-carboxylates which were subsequently modified by bromination, N-alkylation and Pd-catalysed Suzuki cross-coupling reactions. Synthesized ethyl and methyl 3,4-diaryl-1-(2-aryl-2-oxoethyl)-1H-pyrazole-5-carboxylates were evaluated for their physicochemical property profiles and in vitro cytotoxicity against three human colorectal cancer cell lines HCT116, HT29, and SW480. The most active compounds inhibited cell proliferation in a low micromolar range. Selected ethyl 3,4-diaryl-1-(2-aryl-2-oxoethyl)-1H-pyrazole-5-carboxylates were further investigated for their mode of action. Results of combined viability staining via Calcein AM/Hoechst/PI and fluorescence-activated cell sorting data indicated that cell death was triggered in a non-necrotic manner mediated by mainly G2/M-phase arrest.

A general approach towards the synthesis of tetrahydro-4H-pyrazolo[1,5-a][1,4]diazepin-4-one, tetrahydro[1,4]diazepino[1,2-a]indol-1-one and tetrahydro-1H-benzo[4,5]imidazo[1,2-a][1,4]diazepin-1-one derivatives was introduced. A regioselective strategy was developed for synthesizing ethyl 1-(oxiran-2-ylmethyl)-1H-pyrazole-5-carboxylates from easily accessible 3(5)-aryl- or methyl-1H-pyrazole-5(3)-carboxylates. Obtained intermediates were further treated with amines resulting in oxirane ring-opening and direct cyclisation—yielding target pyrazolo[1,5-a][1,4]diazepin-4-ones. A straightforward two-step synthetic approach was applied to expand the current study and successfully functionalize ethyl 1H-indole- and ethyl 1H-benzo[d]imidazole-2-carboxylates. The structures of fused heterocyclic compounds were confirmed by ¹H, ¹³C, and ¹⁵N-NMR spectroscopy and HRMS investigation.

Methyl 2-amino-4-[1-(tert-butoxycarbonyl)azetidin-3-yl]-1,3-selenazole-5-carboxylate as a newly functionalized heterocyclic amino acid was obtained via [3+2] cycloaddition. The structure of the novel 1,3-selenazole was unequivocally confirmed by detailed ¹H, ¹³C, ¹⁵N, and ⁷⁷Se NMR spectroscopic experiments, HRMS and elemental analysis.