Galleria mellonella is a promising in vivo model insect used for microbiological, medical, and pharmacological research. It provides a platform for testing the biocompatibility of various compounds and the kinetics of survival after an infection followed by subsequent treatment, and for the evaluation of various parameters during treatment, including the host–pathogen interaction. There are some similarities in the development of pathologies with mammals. However, a limitation is the lack of adaptive immune response. Antimicrobial photodynamic therapy (aPDT) is an alternative approach for combating microbial infections, including biofilm-associated ones. aPDT is effective against Gram-positive and Gram-negative bacteria, viruses, fungi, and parasites, regardless of whether they are resistant to conventional treatment. The main idea of this comprehensive review was to collect information on the use of G. mellonella in aPDT. It provides a collection of references published in the last 10 years from this area of research, complemented by some practical experiences of the authors of this review. Additionally, the review summarizes in brief information on the G. mellonella model, its advantages and methods used in the processing of material from these larvae, as well as basic knowledge of the principles of aPDT.

Як уникнути eskape патогенів використовуючи екстракти їстівних рослин

Resistant biofilms formed by Staphylococcus aureus on medical devices pose a constant medical threat. A promising alternative to tackle this problem is photodynamic inactivation (PDI). This study focuses on a polyurethane (PU) material with an antimicrobial surface consisting of a composite based on silicate, polycation, and erythrosine B (EryB). The composite was characterized using X-ray diffraction and spectroscopy methods. Anti-biofilm effectiveness was determined after PDI by calculation of CFU mL⁻¹. The liquid PU precursors penetrated a thin silicate film resulting in effective binding of the PU/silicate composite and the PU bulk phases. The incorporation of EryB into the composite matrix did not significantly alter the spectral properties or photoactivity of the dye. A green LED lamp and laser were used for PDI, while irradiation was performed for different periods. Preliminary experiments with EryB solutions on planktonic cells and biofilms optimized the conditions for PDI on the nanocomposite materials. Significant eradication of S. aureus biofilm on the composite surface was achieved by irradiation with an LED lamp and laser for 1.5 h and 10 min, respectively, resulting in a 10,000-fold reduction in biofilm growth. These results demonstrate potential for the development of antimicrobial polymer surfaces for modification of medical materials and devices.

Backround: The agr (accessory gene regulator) quorum sensing (QS) system of Staphylococcus aureus participates significantly in its virulence and biofilm formation—either through its activation or suppression. The aim of this study was to investigate the impact of photoactive nanomaterials that have been functionalized with erythrosine B (EryB) on the modulation of this agr QS system on three methicillin-resistant S. aureus (MRSA). Methods: The functionality of the agr system was determined by the CAMP test and by quantitative PCR (qPCR) to analyze the expression of the hld gene, which is located within the RNAIII and encodes δ-hemolysin. The biofilm was evaluated by crystal violet assay and fluorescence microscopy. The anti-biofilm activity was determined by calculating the colony-forming units. The relative expression of the hld gene, determined by qPCR. Results: Using the CAMP test, S66 and S68 strains were found to be agr-positive, and strain S73 was agr-negative. The relative expression of the hld gene increased only in the agr-positive strains (600- and 1000-fold). In these strains, the biofilm was less compact compared to the dense biofilm formed by the agr-negative strain. The anti-biofilm effectiveness on the nanocomposite with EryB after irradiation reduced the growth of biofilm cells by 100- to 1000-fold compared to the biofilm on polyurethane alone. The qPCR results showed a significant decrease in the relative expression of the hld gene in the agr-positive strains after irradiation compared to the non-irradiated samples. Conclusions: These results suggest that photoactive nanocomposites with EryB can significantly reduce biofilm formed by MRSA strains, regardless of the functionality of the agr QS system.

Based on the screening of some heavy metals (HMs) content in the humus soil horizon of the Transcarpathian region, the regularities of the distribution of HMs in the soils of different landscape zones have been established. It is shown that increasing of the terrain height, the content of HMs in soils decreases (except for Mn and Hg) and for the total HMs content the values of the Spearman correlation coefficient are: Cu – (-0.84); Zn – (-0.83); Mn 0.77; Mo – (-0.91); Co – (-0.82); Pb – (-0.83); Hg – absent; for the content of acid-soluble forms: Cu – absent; Zn – (-0.72); Mn 0.75; Mo – (-0.89); Co – (-0.86); Pb – (-0.77); Hg is absent. This pattern is associated with the tectonic and geological features of the different landscape zones. The calculation of the migration coefficient (the ratio of the content of acid-soluble forms to the gross content) has been shown that in mountainous regions this indicator has the highest value for Zn, Pb, and Cu. That means the potential danger of migration of these heavy me­tals and their bioavailability. This is probably connected to the type of soil in the mountai­nous areas of the region. A pronounced inter-element correlation of the HMs content in soils (except for Hg) has been established and the corresponding values of Pearson’s coefficients for the gross content are: Cu:Zn – 0,96; Cu:Mn – (-0,84); Cu:Mo – 0,89; Cu:Co – 0,99; Cu:Pb – 0,87; Zn:Mn – (-0,79); Zn:Mo – 0,91; Zn:Co – 0,96; Zn:Pb – 0,86; Mn:Mo – (-0,86); Mn:Co – (-0,84); Mn:Pb – (-0,75); Mo:Co – 0,87; Mo:Pb – 0,81; Co:Pb – 0,87. This makes it possible to predict the content of several HMs in the soils of the Transcarpathian region based on the results of determining one of them. In general, the content of HMs in the humus soil horizon (total content and content of mobile forms) is lower than the corresponding values of maximum permissible concentrations.