Metal-based nanoparticles: an alternative treatment for biofilm infection in hard-to-heal wounds.

Metal-based nanoparticles (MNPs) are promoted as effective compounds in the treatment of bacterial infections and as possible alternatives to antibiotics. These MNPs are known to affect a broad spectrum of microorganisms using a multitude of strategies, including the induction of reactive oxygen species and interaction with the inner structures of the bacterial cells. The aim of this review was to summarise the latest studies about the effect of metal-based nanoparticles on pathogenic bacterial biofilm formed in wounds, using the examples of Gram-positive bacterium Staphylococcus aureus and Gram-negative bacterium Pseudomonas aeruginosa, as well as provide an overview of possible clinical applications.

Flavonoid content and antioxidant activity of Artemisia vulgaris L. "hairy" roots.

We investigated the effect of Agrobacterium rhizogenes-mediated transformation on antioxidant activity of Artemisia vulgaris "hairy" roots. It appeared that transformation may increase flavonoid content as well as DPPH-scavenging activity and ability to reduce Fe3+ as compared to the non-transformed plants. Some "hairy" roots accumulated flavonoids up to 73.1 ± 10.6 mg RE/g DW (while the amount of flavonoids in the leaves of non-transformed plants was up to 49.4 ± 5.0 mg RE/g DW). DPPH-scavenging activity of some "hairy" root lines was 3-3.8 times higher than such one of the roots of the control plants. The Fe3+-reducing power of most transgenic root extracts exceeded such power of the extracts of the roots of the control plants. The decrease in SOD activity was found in the most "hairy" root lines compared to the control roots. The increase of flavonoid content correlated with the increase of ability of extracts to scavenge DPPH*- radical and Fe3+ - reducing power. No correlation between SOD activity of extracts and concentration of flavonoids was found (p ≥ 0.2).Thus, transformation has led to the alteration in flavonoid accumulation and antioxidant activity in A. vulgaris "hairy" roots. Transgenic roots with high-antioxidant properties can be selected after A. rhizogenes-mediated transformation.

Phylogenetic characterisation of tick-borne encephalitis virus from Lithuania.

The Baltic states are the region in Europe where tick-borne encephalitis (TBE) is most endemic. The highest notification rate of TBE cases is reported in Lithuania, where the incidence of TBE has significantly increased since 1992. A recent study reported 0.4% prevalence of TBE virus (TBEV) in the two most common tick species distributed in Lithuania, Ixodes ricinus and Dermacentor reticulatus, with the existence of endemic foci confirmed in seven out of Lithuania's ten counties. However, until now, no comprehensive data on molecular characterisation and phylogenetic analysis have been available for the circulating TBEV strains. The aim of this study was to analyse TBEV strains derived from I. ricinus and D. reticulatus ticks collected from Lithuania and provide a genotypic characterisation of viruses based on sequence analysis of partial E protein and NS3 genes. The 54 nucleotide sequences obtained were compared with 81 TBEV strains selected from the NCBI database. Phylogenetic analysis of the partial E and NS3 gene sequences derived from 34 Lithuanian TBEV isolates revealed that these were specific to Lithuania, and all belonged to the European subtype, with a maximum identity to the Neudoerfl reference strain (GenBank accession no. U27495) of 98.7% and 97.4%, respectively. The TBEV strains showed significant regional genetic diversity. The detected TBEV genotypes were not specific to the tick species. However, genetic differences were observed between strains from different locations, while strains from the same location showed a high similarity.

Endophytic Bacterial Biofilm-Formers Associated with Antarctic Vascular Plants.

Deschampsia antarctica and Colobantus quitensis are the only two vascular plants colonized on the Antarctic continent, which is usually exposed to extreme environments. Endophytic bacteria residing within plant tissues can exhibit diverse adaptations that contribute to their ecological success and potential benefits for their plant hosts. This study aimed to characterize 12 endophytic bacterial strains isolated from these plants, focusing on their ecological adaptations and functional roles like plant growth promotion, antifungal activities, tolerance to salt and low-carbon environments, wide temperature range, and biofilm formation. Using 16S rRNA sequencing, we identified several strains, including novel species like Hafnia and Agreia. Many strains exhibited nitrogen-fixing ability, phosphate solubilization, ammonia, and IAA production, potentially benefiting their hosts. Additionally, halotolerance and carbon oligotrophy were also shown by studied bacteria. While some Antarctic bacteria remain strictly psychrophilic, others demonstrate a remarkable ability to tolerate a wider range of temperatures, suggesting that they have acquired mechanisms to cope with fluctuations in environmental temperature and developed adaptations to survive in intermediate hosts like mammals and/or birds. Such adaptations and high plasticity of metabolism of Antarctic endophytic bacteria provide a foundation for research and development of new promising products or mechanisms for use in agriculture and technology.

Prevalence of tick-borne encephalitis virus in questing Dermacentor reticulatus and Ixodes ricinus ticks in Lithuania.

The Baltic States are the region in Europe where tick-borne encephalitis (TBE) is most endemic, with one-third of the European TBE cases detected in Lithuania, Latvia and Estonia. With the Czech Republic and Germany, Lithuania has among the highest population incidences of TBE. Ticks from the Ixodidae family are the main vectors of the TBE virus (TBEV) in Europe. However, there is still a lack of data on the prevalence of TBEV in ticks in different parts of Lithuania. This study analysed the current prevalence of TBEV in the two most common tick species distributed in Lithuania: Ixodes ricinus and Dermacentor reticulatus. Questing I. ricinus (n = 7170) and D. reticulatus (n = 1676) ticks were collected from 81 locations in all ten counties of Lithuania between 2017 and 2019. The presence of TBEV was analysed using a real-time reverse transcription polymerase chain reaction (RT-PCR) and TBEV prevalence in ticks was calculated as the minimum infection rate (MIR). TBEV was detected in the three developmental stages (adults, nymphs and larvae) of I. ricinus and in D. reticulatus adults. The MIR of TBEV in the total sample of I. ricinus was 0.4 % (28/7170) and for D. reticulatus was also estimated to be 0.4 % (6/1676). TBEV-infected ticks were found in 16 locations in seven counties, with MIR ranging from 0.1 % to 1.0 %. The TBEV strains detected belong to the European subtype. To the best of the authors' knowledge, this is the first report on the prevalence of TBEV in unfed D. reticulatus ticks and in I. ricinus unfed larvae in Lithuania.

Agrobacterium rhizogenes-mediated transformation enhances the antioxidant potential of Artemisia tilesii Ledeb.

Plants belonging to the genus Artemisia L. have been used for medicinal purposes since ancient times. These aromatic plants produce and accumulate a wide range of potent secondary metabolites, many of which have shown antioxidant, antiparasitic, antimicrobial, anti-inflammatory, and even anticancer activities. Enhanced biosynthesis of these compounds is a prerequisite for comprehensive studies of their therapeutic properties and cost-efficient use. Transformation of plants with Agrobacterium rhizogenes native root locus (rol) genes is a promising approach to increase the biosynthesis of plant secondary metabolites. The aim of the present study was to evaluate the effects of A. rhizogenes-mediated transformation on the flavonoid contents in hairy roots of medicinal herb A. tilesii Ledeb. Transgenic A. tilesii hairy root lines were analyzed for stable integration of the rolB and rolC transgenes into the plant genome, total flavonoid contents, antioxidant activities of extracts, and the spatiotemporal expression of two flavonoid biosynthetic genes, phenylalanine ammonialyase (PAL) and chalcone synthase (CHS). The flavonoid contents of A. tilesii directly correlated with the antiradical activity and reducing power of their respective lines, with the greatest antioxidant activity found in the plants with the highest level of total flavonoids. Furthermore, all hairy root lines demonstrated altered expression of plant native PAL and CHS genes. Most importantly, A. rhizogenes-mediated transformation enhanced the biosynthesis of natural antioxidants in A. tilesii, producing almost twice the amount of flavonoids than controls. These findings provide an opportunity for the identification of the bioactive molecules in A. tilesii extracts and their potential health benefits.

DNA interaction, antitumor and antimicrobial activities of three-dimensional chitosan ring produced from the body segments of a diplopod.

Commercially available chitins and the chitin isolated from mushrooms, insect cuticles, shells of shrimp, crab and crayfish reported in the literature are in forms of powder, flake or granule. Three-dimensional chitins have been only known from the sponges but still three-dimensional chitosan has not been reported yet. In this study, we produced three-dimensional chitin and chitosan rings from the body segments of a diplopod species (Julus terrestris). Obtained chitin and chitosan rings were characterized (by FT-IR, SEM, TGA, XRD, dilute solution viscometry and EA) and compared with commercial chitin and chitosan. The interactions with plasmid DNA was studied at varying concentrations of chitosan (0.04, 0.4 and 4mg/mL). Antitumor activity tests were conducted (L929 and HeLa), low cytotoxicity and high antiproliferative activity was observed. Antimicrobial activities of J. terrestris chitosan were investigated on twelve microorganisms and maximum inhibition (15.6±1.154mm) was recorded for common human pathogen Staphylococcus aureus.