Antarctica's unique environment supports diverse avian populations, including penguins, skuas, and gulls. As climate-driven pressures on these populations intensify, their microbiota receives increased attention due to their relevance for host health. In this study, we investigated 11 bacterial isolates associated with Antarctic birds using a polyphasic taxonomic approach integrating genomic and phenotypic data. Phylogenetic analysis of 16S rRNA gene sequences and core-genome-based phylogenomics separated the strains into three groups and genome-relatedness indices confirmed that the three lineages represent novel species within the genus Rothia. Functional genomic analysis, combined with phenotypic testing, revealed broad metabolic capabilities with adaptations to host-associated environment. Further genome mining revealed the presence of several biosynthetic gene clusters, potentially encoding terpenes, siderophores, and other bioactive compounds. Some of these clusters likely encode variants of enterobactin, a nonribosomally synthesized siderophore. However, in vitro production of enterobactin was not confirmed, suggesting more complex expression regulation than iron depletion alone. Together, these findings broaden the known diversity of Rothia by three proposed novel species, Rothia ornithocola sp. nov., Rothia pygoscelis sp. nov., and Rothia antarctica sp. nov., and highlight genomic and phenotypic features that contribute to the ecology of Antarctic avian-associated bacteria.

Strain CCM 2573 is a Gram-positive bacterium that has been intensively studied in the past due to its distinct chemotaxonomic properties, but its reliable taxonomic classification has not been satisfactorily clarified. Whole-genome sequencing and comparative genomic analyses performed in this study revealed that the strain belongs to the Macrococcus caseolyticus phylogenetic clade. Genome-to-genome comparisons confirmed the closest relationship to the type strains of M. caseolyticus subsp. hominis CCM 7927T and M. caseolyticus subsp. caseolyticus DSM 20597T. However, the strain harbored unique genomic elements distinguishing it from its nearest phylogenetic neighbors. Its accessory genome contains dozens of insertion sequences, a 92-kbp composite transposon with unique palindromic repeat loci associated with a CRISPR-Cas adaptive immune system, a pseudo-staphylococcal chromosome cassette, and several additional genomic islets. Unlike other macrococci, strain CCM 2573 exhibits a specific peptidoglycan composition (L-Lys-Gly₂-Ser₂-Gly) and shows a higher phylogenetic divergence of aminoacyltransferases (FemABX) involved in interpeptide bridge synthesis. In addition, it reveals distinct biochemical characteristics from both subspecies of M. caseolyticus, particularly in its ability to produce acid from galactose, cellobiose, melezitose, and turanose, as well as in its susceptibility to novobiocin. The MALDI-TOF mass spectra enable differentiation of the strain from other type strains of the genus Macrococcus. The results of polyphasic taxonomy obtained in this study showed that strain CCM 2573 belongs to the species M. caseolyticus, but it is distinct from both validly named M. caseolyticus subspecies. We propose to assign the analyzed strain as a new subspecies, Macrococcus caseolyticus subsp. lactis subsp. nov. The type strain is CCM 2573T (= DSM 20227T).

Studying permafrost in Antarctica provides insights into climate history, soil and rock structure, and a unique biodiversity with potential impact on ecosystems. Although a great deal of effort has been devoted to the microbiological composition of permafrost soils, the objective pursued in this study is, for the first time, to examine soil and rock samples collected from a 350 cm deep core drilled near the Johann Gregor Mendel Czech Antarctic Station on the Ulu Peninsula of James Ross Island, to study the effect of geochemical properties on microbial composition and diversity and vice versa. We collected samples from the profile starting on the ground surface down to 350 cm depth and correlated information from metagenomic 16S rRNA gene analysis and geochemical data. The 80-cm-thick active layer had a distinct bacterial composition different from the Pseudomonadota-rich permafrost layer, with Actinomycetota, Acidobacteriota, Chloroflexota, and Verrucomicrobiota being the prevalent phyla. Throughout the core, the higher bacterial diversity was positively associated with the sand fraction and intensive weathering. The highest identified diversity in the deepest part of the active layer (transient active layer) suggests that the bacteria here have been gradually cryopreserved, possibly accumulating from the upper layers. In summary, the identified interface between the active layer and permafrost, as well as the transition within the permafrost from Holocene marine sediments to underlying Cretaceous sedimentary rocks (deeper than similar to 260 cm), had the greatest influence on the bacterial composition. Decadal records of soil temperature and active layer thickness predict more significant interactions in the future between bacterial communities in the current active layer and mineral weathering bacteria that are typical of permafrost.

En.te.ro.coc'cus. Gr. neut. n. enteron , intestine; N.L. masc. n. coccus , coccus; from Gr. masc. n. kokkos, grain, seed; N.L. masc. n. Enterococcus , intestinal coccus. Bacillota / Bacilli / Lactobacillales / Enterococcaceae / Enterococcus Bacteria of the genus Enterococcus are Gram‐stain‐positive, non‐spore‐forming, facultatively anaerobic, and catalase‐negative ovoid cocci occurring singly, in pairs or in short chains. Phylogenetically, the genus belongs to the family Enterococcaceae within the phylum Bacillota . These microorganisms are a natural part of the microbiota of various invertebrates and vertebrates, including humans, but they can also be found in both marine and freshwater environments, on aquatic and terrestrial plants, and, to a lesser extent, in soil. Selected strains are beneficial in the food industry, where they are part of bacterial communities involved in the fermentation of dairy, plant, and meat products. However, they can also be agents of food spoilage. Certain strains are used in several commercial probiotic preparations due to their beneficial effects on human and animal health. In contrast, due to their opportunistic pathogenic potential and frequent multidrug, high‐level resistance to antimicrobial agents, enterococci are leading causes of healthcare‐associated infections, urinary tract infections, and endocarditis. At the time of writing, the genus consists of 63 species validly named according to the International Code of Nomenclature of Prokaryotes (ICNP). The type species is Enterococcus faecalis Schleifer and Kilpper‐Bälz 1984 VP (basonym: Streptococcus faecalis Andrewes and Horder 1906 AL ). DNA G + C content (mol%) : 34.5–44.5 (genome). Type species : Enterococcus faecalis Schleifer and Kilpper‐Bälz 1984 VP (basonym: Streptococcus faecalis Andrewes and Horder 1906 AL ).

The gut microbiota of four Antarctic marine fish species-Notothenia coriiceps, Trematomus bernacchii, Trematomus hansoni, and Trematomus newnesi-were analysed, with a particular focus on the members of the Enterobacter cloacae complex. Nineteen isolated strains were characterised by rep-PCR, automated ribotyping, extended phenotyping, and MALDI-TOF MS analysis. Fingerprinting methods grouped the psychrotolerant isolates into two distinct groups, representing the dominant enteric bacteria in the gut contents of these fish. Following their preliminary identification as members of the Enterobacter cloacae complex, additional phylogenetic analyses were conducted using the 16S rRNA and rpoB genes, as well as fatty acid analysis and wholegenome sequencing of two representatives selected based on their fingerprints. All results indicated that the analysed group represents a new autochthonous Enterobacter taxon inhabiting the gut of fish of the family Nototheniidae. Based on average nucleotide identity (ANI) and in silico DNA-DNA hybridization (dDDH) values, the "Enterobacter hoffmannii", the effectively published but non-valid name, was the most closely related species to representatives of both groups of isolates from the gut of the above-specified notothenioid fish. The name Enterobacter hoffmannii subsp. nototheniae subsp. nov. is proposed, with the type strain P5473T (= CCM 8629T = LMG 34031T), for isolates of Group 1. At the same time, the name Enterobacter hoffmannii subsp. hoffmannii subsp. nov. is suggested for isolates of Group 2, with the existing type strain DSM 14563T =

Nucleic acids (NAs) extraction is a critical step in molecular biology. Traditional methods, such as phenol-chloroform extraction and spin-column purification, present automation and scalability limitations. In this study, we present the synthesis, scale-up, characterization, and application of MPs for the automated NAs extraction from HCV and CMV. These pathogens are routinely included in high-throughput screening assays, underscoring the necessity for automated NAs isolation processes. We scaled the synthesis from 1 L to 5 L batch volumes, yielding MPs with consistent physicochemical properties and an average particle diameter of 44.72-46.57 nm. Larger-scale MPs maintained extraction efficiency with minimal Ct variation (≤1.0) across replicates. Compared to commercial alternatives, our hydrated MPs demonstrated over 5 % improvement in DNA extraction efficiency., though RNA recovery exhibited higher variability. Additionally, we investigated the stability and storage conditions of MPs in hydrated and lyophilized forms. Hydrated MPs consistently outperformed lyophilized counterparts, showing up to a 3.5 Ct lower value in DNA extraction, corresponding to a higher than 1-log increase in extraction efficiency. This study demonstrates the successful scale-up of TEOS modified MPs while maintaining batch-to-batch consistency and long-term stability over two years. The developed MPs offer a robust, cost-effective, and efficient platform for automated NAs extraction, with potential for integration into molecular diagnostics, high-throughput workflows, and point-of-care diagnostic tools, particularly in decentralized or resource-limited settings.

Three bacterial strains producing blue-violet pigmented colonies on R2A agar were isolated from a wet rock wall and lakes in the deglaciated northern part of James Ross Island, Antarctica. The isolated strains inhibited phytopathogenic Gram-positive bacteria Clavibacter spp., Curtobacterium flacumfaciens, and Paenarthrobacter ilicis. Phylogenetic analysis based on the 16S rRNA gene indicated that the isolates belonged to the genus Massilia and the closest relatives were Massilia violaceinigra B2T, Massilia rubra CCM 8692T, Massilia frigida CCM 8695T, Massilia antarctica CCM 8941T, and Massilia aquatica CCM 8693T. A polyphasic taxonomic study based on lepA genes sequencing, automated ribotyping, MALDI-TOF MS, chemotaxonomy analyses, extensive biotyping, average nucleotide identity, and digital DNA-DNA hybridization calculations based on whole-genome sequences proved that the isolates represent a novel Massilia species for which the names Massilia pseudoviolaceinigra sp. nov. and Massilia scottii sp. nov. are suggested, with the type strains P3689T (= CCM 9206T = LMG 33568T) and P5043T (= CCM 9029T = LMG 32502T), respectively. These two bioactive metabolite-producing species may play an important role in shaping the composition of fresh-water Antarctic microbiomes due to the inhibition of various Gram-positive bacteria.

Our taxonomic study was aimed at characterizing enteric bacteria isolated from faecal samples of Magellanic penguins (Spheniscus magellanicus) collected in Cabo Virgenes, Patagonia, Argentina, in 2016 and 2017. Initial sequencing of the 16S rRNA gene assigned two psychrotolerant strains, P6884T and P7711T, to the genus Erwinia. The closest phylogenetic relatives of the strains were Erwinia billingiae and Erwinia endophytica type strains, with 16S rRNA gene sequence similarity values between 98.4

ABSTRACT Macrococci are usually found as commensals on the skin and mucosa of animals and have been isolated from mammal-derived fermented foods; however, they can also act as opportunistic pathogens. Here, we used whole-genome sequencing, comparative genomics, extensive biotyping, MALDI-TOF mass spectrometry, and chemotaxonomy to characterize Macrococcus sp. strains isolated from livestock and human-related specimens. Based on the results of polyphasic taxonomy, we propose the species Macrococcus psychrotolerans sp. nov. (type strain NRL/St 95/376 T = CCM 8659 T = DSM 111350 T ) belonging to the Macrococcus caseolyticus phylogenetic clade. It grows at 4°C, and the core genome of the isolates contains suspected genes contributing to low-temperature tolerance. Variable genetic elements include prophages, chromosomal islands, a composite staphylococcal cassette chromosome island, and many plasmids that affect the overall genome expansion and adaptation to specific ecological settings of the studied isolates. Large plasmids carrying the methicillin resistance gene mecB were identified in M. psychrotolerans sp. nov. strains and confirmed as self-transmissible to Staphylococcus aureus in vitro . In addition to plasmids with circular topology, a 150-kb-long linear plasmid with 14.1-kb-long inverted terminal repeats, harboring many IS elements and putative genes for a type IV secretion system was revealed. The described strains were isolated from human clinical material, food-producing animals, meat, and a wooden cheese board and have the potential to proliferate at refrigerator temperatures. Their presence in the food chain and human infections indicates that attention needs to be paid to this potential novel opportunistic pathogen. IMPORTANCE The study offers insights into the phenotypic and genomic features of a novel species of the genus Macrococcus that occurs in livestock, food, and humans. The large number of diverse mobile genetic elements contributes to the adaptation of macrococci to various environments. The ability of the described microorganisms to grow at refrigerator temperatures, enabled by genes that are predicted to contribute to low-temperature tolerance, raises food safety concerns. Confirmed in vitro conjugative transfer of plasmid-borne mecB gene to S. aureus poses a significant risk of spread of broad β-lactam resistance. In addition, the intergeneric plasmid transfer to S. aureus is indicative of horizontal gene transfer events that may be more frequent than generally accepted. Determining a complete sequence and gene content of linear megaplasmid with exceptional topology for the Staphylococcaceae family suggests its possible role in shuttling adaptive traits through an exchange of genetic information.

Magnetic particles are an effective tool for simple, time-saving, and labour-saving nucleic acid extraction. In this study, we investigated the isolation of nucleic acids (NA) using 11 variants of magnetic nanoparticles (MPs, 52 +/- 6.8 nm) with a surface concentration of amine groups up to 20.8 nmol & sdot; mg-1. All results were compared with morphologically identical magnetic material modified with SiO2 grafted with (3-aminopropyl)triethoxysilane (APTES). The properties of these materials were characterized by transmission electron microscopy, scanning electron microscopy, dynamic and electrophoretic light scattering, and magnetometry. Concentrations of amine groups on MPs-APTES were determined by the chemical bind and release method with photometric quantification. The isolation potential of the proposed materials toward NAs was evaluated using gel electrophoresis with photometric determination of NAs concentrations and RT-qPCR. Our results show that the NAs yields of MPsAPTES are higher than the reference MPs-SiO2, regardless of the amine group concentrations. Although the total yield decreased with the concentration of amine groups, a different affinity towards genomic DNA (gDNA) was observed. A high concentration of grafted amine groups induced a preference for ribosomal RNA (rRNA) over gDNA and mediated effective NA elution. Densitometric image analysis of gDNA bands showed that NAs isolated by MPs-SiO2 contained significantly higher DNA levels than MPs with 1/32 %, 1/2 %, and 16 % APTES modification, which was subsequently confirmed by qPCR. Gene expression analysis performed by RT-qPCR revealed that unwanted gDNA contamination did not significantly affect the threshold cycles (Ct) of target genes when cDNA-specific primers were used, but may lead to overestimation when targeting genes with low expression and no possibility to design cDNA-unique primers. From a practical point of view, MPs-APTES provided better dose-dependent NA isolation performance with stable NA quality.

The introduced work represents an implementation of the automatic benchtop electrochemical station (BES) as an effective tool for the possibilities of high-throughput preparation of modified sensor/biosensors, speeding up the development of the analytical method, and automation of the analytical procedure for the determination of paracetamol (PAR) and dopamine (DOP) as target analytes. Within the preparation of gold nanoparticles modified screen-printed carbon electrode (AuNPs-SPCE) by electrodeposition, the deposition potential EDEP, the deposition time tDEP, and the concentration of HAuCl4 were optimized and their influence was monitored on 1 mM [Ru(NH3)6]3+/2+ redox probe and 50 μM DOP. The morphology of the AuNPs-SPCE prepared at various modification conditions was observed by SEM. The analytical performance of the AuNPs-SPCE prepared at different modification conditions was evaluated by a construction of the calibration curves of DOP and PAR. SPCE and AuNPs-SPCE at modification condition providing the best sensitivity to PAR and DOP, were successfully used to determine PAR and DOP in tap water by “spike-recovery” approach. The BES yields better reproducibility of the preparation of AuNPs-SPCE (RSD = 3.0%) in comparison with the case when AuNPs-SPCE was prepared manually by highly skilled laboratory operator (RSD = 7.0%). Graphical abstract

Microbial communities in the active layer play a crucial role in the biogeochemical cycles of Antarctic pristine ecosystems. Here, 16S rRNA gene sequencing was used to investigate bacterial communities in active layer of five different geological sites related to the compositional variation of the geological bedrock, including Neogene volcanic or Cretaceous rocks and or marine sediments areas of distinct elevation. Local variations in the thickness of the active layer (50–80 cm) were observed on the Ulu Peninsula, James Ross Island, and the southwest coast of Vega Island, Antarctica during sampling in 2019. High bacterial diversity was detected in all sampling sites. Significant site effects on bacterial composition with increased Chloroflexota and decreased Flavobacteriaceae were only observed between the highest elevation Johnson Mesa 2 plateau and coastal areas. The overall effect of the depth was reflected by the increased of e.g., Cyanobacteria , Propionibacterium , Staphylococcus in the upper surface and Chloroflexota , Acidobacteriota , Actinomycetota at depths below 30 cm. The huge number of unassigned bacteria indicated a potential source of new bacterial species and their ecological role in this extreme environment. For the first time, we showed that the effect of depth on bacterial composition was more significant than the effect of geological bedrock from these previously unexplored regions.

The taxonomic status of strain P5891 T , isolated from an Adélie penguin beak swab, was investigated. Based on the 16S rRNA gene sequence, the strain was identified as a potentially novel Corynebacterium species, with the highest sequence similarities to Corynebacterium rouxii FRC0190 T (96.7 %) and Corynebacterium epidermidicanis DSM 45586 T (96.6 %). The average nucleotide identity values between strain P5891 T and C. rouxii FRC0190 T and C. epidermidicanis DSM 45586 T were 68.2 and 69.2 %, respectively. The digital DNA–DNA hybridization values between strain P5891 T and C. rouxii FRC0190 T and C. epidermidicanis DSM 45586 T were 23.7 and 21.4 %, respectively. Phylogenetic trees based on the 16S rRNA sequence placed strain P5891 T in a separate branch with Corynebacterium canis 1170 T and Corynebacterium freiburgense 1045 T , while a phylogenomic tree based on the Corynebacterium species core genome placed the strain next to Corynebacterium choanae 200CH T . Extensive phenotyping and genomic analyses clearly confirmed that strain P5891 T represents a novel species of the genus Corynebacterium , for which the name Corynebacterium mendelii sp. nov. is proposed, with the type strain P5891 T (=CCM 8862 T =LMG 31627 T ).

Two-dimensional materials have recently gained significant awareness. A representative of such materials, black phosphorous (BP), earned attention based on its comprehensive application potential. The presented study focuses on the mode of cellular response underlying the BP interaction with Chlamydomonas reinhardtii as an algal model organism. We observed noticeable ROS formation and changes in outer cellular topology after 72 h of incubation at 5 mg/L BP. Transcriptome profiling was employed to examine C. reinhardtii response after exposure to 25 mg/L BP for a deeper understanding of the associated processes. The RNA sequencing has revealed a comprehensive response with abundant transcript downregulation. The mode of action was attributed to cell wall disruption, ROS elevation, and chloroplast disturbance. Besides many other dysregulated genes, the cell response involved the downregulation of GH9 and gametolysin within a cell wall, pointing to a shift to discrete manipulation with resources. The response also included altered expression of the PRDA1 gene associated with redox governance in chloroplasts implying ROS disharmony. Altered expression of the Cre-miR906–3p, Cre-miR910, and Cre-miR914 pointed to those as potential markers in stress response studies.

Background:As highlighted by recent pandemic outbreaks, antiviral drugs are crucial resources in the global battle against viral diseases. Unfortunately, most antiviral drugs are characterized by a plethora of side effects and low efficiency/poor bioavailability owing to their insolubility. This also applies to the arylnaphthalide lignin family member, diphyllin (Diph). Diph acts as a vacuolar ATPase inhibitor and has been previously identified as a promising candidate with broad-spectrum antiviral activity. However, its physicochemical properties preclude its efficient administration in vivo, complicating preclinical testing.Methods:We produced human recombinant H- ferritin (HsaFtH) and used it as a delivery vehicle for Diph encapsulation through pH-mediated reversible reassembly of HsaFtH. Diph nanoformulation was subsequently thoroughly characterized and tested for its non-target cytotoxicity and antiviral efficiency using a panel of pathogenic viral strain.Results:We revealed that loading into HsaFtH decreased the undesired cytotoxicity of Diph in mammalian host cells. We also confirmed that encapsulated Diph exhibited slightly lower antiviral activity than free Diph, which may be due to the differential uptake mechanism and kinetics of free Diph and Diph@HsaFtH. Furthermore, we confirmed that the antiviral effect was mediated solely by Diph with no contribution from HsaFtH.Conclusion:It was confirmed that HsaFtH is a suitable vehicle that allows easy loading of Diph and production of highly homogeneous nanoparticles dispersion with promising broad-spectrum antiviral activity.

Malic acid is one of the most important acids in the food industry and in fermentation processes.Especially in the wine fermentation process, its decreasing concentration plays a significant role.During the process of malolactic fermentation of wine, it is converted into lactic acid, so accurate monitoring of malic acid could lead to improvements in winemaking technology.An electrochemical sensor based on nanomaterials could be used as a suitable tool.Traditionally sensors used enzymes for the determination of malic acid, but they are usually hard to store and expensive.One possibility to replace them is nanomaterials with enzymatic activity (nanozymes).Nanozymes, on the other hand, demonstrate robustness in various environments, making them invaluable tools in both industrial and biomedical applications.One key advantage of nanozymes is their tailorability.By manipulating their size, composition, and structure, researchers can design nanozymes with specific catalytic activities, mimicking natural enzymes or even surpassing their efficiency.This experiment used a combination of ZnONPs (zinc oxide nanoparticles) with a combination of MWCNTs (multi-walled carbon nanotubes) as a tool for the determination of malic acid.

In this study, we introduce a method for modifying poly(lactic acid) (PLA) filament, which is adjustable to enhance the rheological properties and biocompatibility of printed products or impart specific characteristics by bonding nanoparticles onto the surface of graphene oxide.What distinguishes our method is the postproduction modification of PLA filament before the printing process.Graphene oxide, being a unique nanomaterial with diverse applications in science and technology, serves as a platform for modification due to the presence of functional groups on its surface that are accessible for binding modifiers or nanoparticles.The persistence of graphene oxide on the surface of printed items even after 3D printing highlights its potential for further modifications.This presence was verified through scanning electron microscopy and Raman spectroscopy.

One of the most problematic invasive species in Europe are knotweeds from genus Reynoutria (Fallopia) which have significant negative impact on the native communities as well on human activities. Therefore, they are a target of many control programmes. Due to their high regeneration potential, their management is problematic, and only chemical treatment is reported to be sufficiently effective. The aim of this paper was to describe and analyse the patterns of Reynoutria invasion under long-term chemical treatment with glyphosate-based herbicide in The Morávka river floodplain, Czech Republic. The data covers 17 years of management which started with the European project “Preservation of alluvial forest habitats in the Morávka river basin”. We focus on (i) assessment of Reynoutria distribution during long-term management, (ii) analysis of the change of distribution according to the habitat, and (iii) discussion of the optimal management strategy based on the long-term data. Distribution data was obtained using GNSS field mapping. Before the start of the study in 2007, Reynoutria stands covered 29% of the study area (96.9 ha). As a result of systematic whole area chemical management, the extent decreased to 19.6% (65.3 ha) in 2009, and even reached 14.5% (48.2 ha) in 2013, three years after its end. Due to implementation of local chemical management in the following years, the area of Reynoutria was maintained at similar level, with minimum value 41.8 ha in 2018 and a slight increase in recent mapping in 2023. Beside the extent, the structure and coverage of invaded sites was analysed. There was a clear trend of fragmentation of larger polycormons with high coverage into many smaller and less dense ones as a result of chemical spraying. The average size of Reynoutria stand decreased from 0.61 ha in 2007 to half in 2013 (0.32 ha) to 0.15 ha in 2023. Testing of the effects of time, habitat, and biotope did not reveal significant differences of changes of extent and abundance over different environments (forest, open, bare ground), which indicates that there are no differences in reaction to management in the studied habitat and vegetation types. Our study provides a robust and unique overview of the invasion, reinvasion, and suppression dynamics for an important invasive species. If herbicide management is used, chemical treatment must be quite long-term as even three years of intensive glyphosate foliar spray application was not sufficient for the complete eradication of Reynoutria. Therefore, we propose the following procedure for effective chemical management of Reynoutria: 1) In largely infested sites, the first step is to reduce the distribution of Reynoutria stands to isolated polycormons. This phase can last 3–5 years. 2) After reaching the state of sparse distribution of Reynoutria, we recommend herbicide application only in periods of every 3–5 years depending on the local context and rate of regrowth. 3) At sites exposed to soil disturbances, where the soil is contaminated by fragments of Reynoutria rhizomes, there is a need to apply herbicide immediately to target newly resprouting individuals.

BACKGROUND:Bovine mastitis is one of the main causes of reduced production in dairy cows. The infection of the mammary gland is mainly caused by the bacterium Staphylococcus aureus, whose resistant strains make the treatment of mastitis with conventional antibiotics very difficult and result in high losses. Therefore, it is important to develop novel therapeutic agents to overcome the resistance of mastitis-causing strains. In this study, novel selenium-tellurium based nanoparticles (SeTeNPs) were synthesized and characterized. Their antibacterial activity and biocompatibility were evaluated both in vitro and in vivo using a bovine model. A total of 10 heifers were divided into experimental and control groups (5 animals each). After intramammary infection with methicillin resistant S. aureus (MRSA) and the development of clinical signs of mastitis, a dose of SeTeNPs was administered to all quarters in the experimental group. RESULTS:Based on in vitro tests, the concentration of 149.70 mg/L and 263.95 mg/L of Se and Te, respectively, was used for application into the mammary gland. Three days after SeTeNPs administration, MRSA counts in the experimental group showed a significant reduction (P < 0.01) compared to the control group. The inhibitory effect observed within the in vitro experiments was thus confirmed, resulting in the suppression of infection in animals. Moreover, the superior biocompatibility of SeTeNPs in the organism was demonstrated, as the nanoparticles did not significantly alter the inflammatory response or histopathology at the site of application, i.e., mammary gland, compared to the control group (P > 0.05). Additionally, the metabolic profile of the blood plasma as well as the histology of the main organs remained unaffected, indicating that the nanoparticles had no adverse effects on the organism. CONCLUSIONS:Our findings suggest that SeTeNPs can be used as a promising treatment for bovine mastitis in the presence of resistant bacteria. However, the current study is limited by its small sample size, making it primarily a proof of the concept for the efficacy of intramammary-applied SeTeNPs. Therefore, further research with a larger sample size is needed to validate these results.

Grapevine trunk pathogens (GTPs) cause serious damage to grapevines and have significant economic impacts. There is no effective protection against grapevine trunk diseases. Newly designed AgSe nanoparticles (NPs) and CuSe NPs, single-element Ag NPs, Cu NPs, Se NPs and selected chemicals or chemical agents such as sodium arsenite, 8-hydroxyquinoline, silver nitrate, colloidal silver, Altron Silver fertilizer and silver thiosulfate complex (NH4)(3)/Ag(S2O3)(2) were tested in vitro against two serious GTPs Diaporthe eres, Eutypa lata and Diplodia seriata isolated from walnut. The most significant inhibition of fungal growth was observed for silver nitrate and AgSe NPs, which showed the highest level of half the maximum effective EC50 concentration with the lowest concentrations. In the case of silver nitrate at a concentration of 1000 mg L-1, 79% inhibition of mycelial growth was observed for the pathogen E. lata, 48% for D. seriata and 54% for D. eres. AgSe NPs, in which the concentration of silver is 2588 mg L-1 and that of selenium is 902 mg L-1, showed 68% inhibition of mycelial growth in the pathogen E. lata, 54% in D. seriata and 58% in D. eres.