Science, Technology and Innovation

Tryptophan as a molecular microswitch: Integrating BioLiP statistical insights with MD simulations of 5-HT₂ receptors

Karina Pakosz — 2026-08-17

Tryptophan residues play a critical role in protein-ligand recognition owing to their unique aromatic character, high polarizability, and ability to participate in diverse noncovalent interactions, including π-π stacking, cation-π interactions, hydrogen bonding, and hydrophobic contacts. In this study, a two-stage approach was employed to elucidate the functional significance of tryptophan residues within ligand-binding sites across diverse protein systems. First, a large-scale statistical analysis was performed using a curated dataset of protein-ligand complexes extracted from the BioLiP database. The dataset was analysed with respect to enzymatic classification and Gene Ontology enrichment, revealing a pronounced enrichment of tryptophan residues in the binding sites of hydrolases, oxidoreductases, and transferases, as well as strong associations with metal-ion binding, redox-related functions, and membrane or cytoplasmic localization. Within the G protein-coupled receptor (GPCR) superfamily, rhodopsin-like class A receptors were identified as the most prominently represented group featuring tryptophan-mediated ligand interactions. In the second stage, molecular dynamics simulations were conducted for selected serotonin 5-HT₂ receptor subtypes (5-HT₂_A, 5-HT₂_B, and 5-HT₂_C) to provide atomistic insights into the role of the conserved W6.48 residue. The simulations reveal a stable spatial relationship between the ligand and W6.48, characterized by distances consistent with aromatic anchoring, supporting its role in maintaining ligand orientation and binding pocket organization. Collectively, these results highlight tryptophan as a key determinant of ligand recognition and stabilization across both enzymatic and receptor-mediated systems.

A preliminary study on the spatial distribution of lead, cadmium, aluminium, and copper in different potato (Solanum tuberosum L.) varieties — implications for food safety and risk assessment

Michał Marek — 2026-08-18

Food safety regarding heavy metal contamination is a critical global challenge due to the toxic nature of these elements and their ability to bioaccumulate in the food chain. This pilot study investigates the spatial distribution at different depths of potato tubers (Solanum tuberosum L.), of toxic elements such as lead and cadmium (both highly toxic) as well as aluminium (far less toxic compared to the previous two) and copper (micronutrient) to evaluate the efficacy of culinary processing in reducing toxic metal exposure. Three popular cultivars in southern Poland – “Soraya”, “Vineta”, and “Jelly” available on the Tarnów market were analyzed. Following the wet digestion step, the quantitative determination of selected metals was performed using Graphite–Furnace Atomic Absorption Spectrometry (Agilent 240Z AA). The accuracy of the analyses was validated using certified reference materials. The most interesting findings indicate that while mechanical peeling of tubers effectively minimizes exposure to Pb, it does not significantly reduce Cd levels. Analysis of behavior of aluminium revealed a distribution pattern similar to that observed for lead. Mechanical peeling led to a substantial reduction in the content of lead (69.0–82.0%) and aluminium (96.8–98.6%), as both elements strongly accumulated within the outermost periderm. Conversely, cadmium exhibited high mobility throughout the internal tissues, resulting in a minimal post-peeling concentration decrease ranging from 5.6% to 36.1%.

Evaluation of the effectiveness of three disinfectants used for chicken hatching egg disinfection based on microbiological analyses and hatchability results

Ewelina Węsierska — 2026-08-19

Objective: The aim of the study was to compare three commercial disinfection procedures for chicken hatching eggs with respect to eggshell microbial contamination, embryonic mortality, macroscopic signs of egg-content contamination, and hatchability.

Materials and methods: A single commercial batch of 2,250 hatching eggs from 59-week-old Ross 308 broiler breeders was divided into three groups of 750 eggs. Eggs were disinfected with 1% Virocid®, 1% Virkon S®, or Fumagri HA® applied by fumigation at 0.8 g/m³. Due to the study being conducted under commercial hatchery conditions, where all hatching eggs undergo routine disinfection, it was not possible to establish an untreated control group comprising eggs that had not been subjected to disinfection. Microbiological samples were collected before disinfection and 15 min after treatment. Incubation outcomes were evaluated by candling, hatch records, and breakout examination of rejected and unhatched eggs. Categorical data were analysed using chi-square tests, pairwise comparisons of proportions, and relative risk (RR).

Results: Hatchability of fertile eggs was 83.3%, 86.0%, and 87.1% for Virocid®, Virkon S®, and Fumagri HA®, respectively, with no significant overall difference among treatments (p = 0.140). The distribution of embryonic mortality across incubation periods was also not significantly affected by the disinfection procedure (p = 0.130). Macroscopic signs of egg-content contamination were less frequent after Fumagri HA® than after Virocid® treatment (1.1% vs 3.3%; RR = 0.35). Microbiological analyses showed no consistent reduction in total microbial counts after disinfection. No colonies with morphology typical of Salmonella or Pseudomonas were detected on the screening media used.

Conclusions: The three disinfection procedures did not significantly differ in overall hatchability or embryonic mortality. However, Fumagri HA® was associated with the lowest frequency of macroscopically identified egg-content contamination. The lack of concordance between eggshell microbiological results and embryological outcomes indicates that hatchery disinfection should be evaluated using both microbiological and incubation-related criteria. Because the study involved a single commercial batch and limited microbiological replication, the findings should be regarded as preliminary.

The first record of Cobitis taenia and Sabanejewia baltica, and the rediscovery of Rhodeus amarus in the Dunajec River — comparison with historical ichthyological data

Mariusz Klich — 2026-08-19

Objective: The aim of this study was to document the occurrence of Cobitis taenia, Sabanejewia baltica and Rhodeus amarus in the Dunajec River in 2022 and to verify their previous status using available ichthyological records.

Material and methods: Electrofishing was conducted in July 2022 at three representative sites in the lower Dunajec River near Tarnów. A total of 612 fish were collected. The results were compared with historical ichthyological publications concerning the Dunajec River and its tributaries from 1880 to 2006.

Results: Eighteen fish species were recorded, including C. taenia, S. baltica and R. amarus. The historical analysis covered 27,745 fish from the Dunajec River and 33,757 fish from its tributaries and revealed no previous reliable records of C. taenia or S. baltica in the Dunajec River. For R. amarus, historical occurrence in the Dunajec catchment was confirmed, while the 2022 observation represents a rediscovery of the species in the Dunajec River after a long interval.

Conclusions: The findings update knowledge of the regional distribution of the studied species. The cause of their occurrence in the lower Dunajec River cannot be determined conclusively from the present study and requires further monitoring.

Assessment of indoor chemical pollutant emissions from scented candle burning

Marek Chyc — 2026-08-21

Background: Scented candles are widely used indoors for decorative and aromatherapeutic purposes, but combustion may contribute to the accumulation of gaseous pollutants and deterioration of indoor air quality.

Objective: To assess temporal changes in formaldehyde, total volatile organic compounds, carbon dioxide, carbon monoxide, and benzene during the combustion of three commercially available scented candles.

Materials and methods: Three different scented candle products were tested individually in a residential room with a floor area of 11 m² and an approximate volume of 25 m³. Each candle was burned for 60 minuts in a closed room. Pollutant concentrations were monitored using a low-cost ZN-MT32 multi-parameter air-quality sensor at 0, 5, 10, 15, 30, 45, and 60 minuts. One experimental run was performed for each candle.

Results: Carbon dioxide increased for all candles. The increases after 60 minuts were 414 mg/m³ for candle A, 493 mg/m³ for candle B, and 326 mg/m³ for candle C. Formaldehyde showed the maximum concentration for candle C, reaching 132 µg/m³, while maximum concentrations for candles B and A were 55 and 24 µg/m³, respectively. Maximum total volatile organic compounds concentrations were 332, 139, and 64 µg/m³ for candles C, B, and A, respectively. No measurable changes in carbon oxide or benzene were observed under the experimental conditions.

Conclusions: The tested candles produced different temporal pollutant profiles. Candle C showed the highest formaldehyde and total volatile organic compounds concentrations, whereas candle B produced the largest increase in indoor carbon dioxide. The findings support the need for adequate ventilation during prolonged candle use. Because the study used a low-cost sensor and a single experimental run per product, the results should be regarded as indicative rather than as reference-grade emission measurements.

Scientific Conference "Innovative solutions in speech therapy diagnosis - application of the INIA system to assess sound articulation", Tarnów, November 25, 2025

Kinga Kusiak-Witek — 2026-08-19

This article is a conference report containing abstracts of presentations presented during the conference Innovative Solutions in Speech Therapy Diagnosis – Application of the INIA System to Assess Articulation, which took place on November 25, 2025, in the Jan Szczepanik Auditorium at Tarnów University. It reflects the meeting of scientific and practical communities representing speech therapy, pedagogy, linguistics, computer science, and engineering and technical sciences, whose common goal remains the development of modern, objective methods of speech diagnosis. The collected abstracts document the main threads of discussion during the conference, demonstrating both the current state of research and the practical possibilities of applying new technologies in the diagnosis of articulation disorders.