Hydrochemical Characteristics of Four Retreating Glacier Forefields Off the Coast of Admiralty Bay (King George Island, Maritime Antarctic)

This study examines the impact of geological, marine and anthropogenic sources on metal and metalloid concentrations in the forefields of four glaciers (Ecology, Sphinx, Tower and Windy) on King George Island, Antarctic. Water samples were collected at the beginning and end of the hydrological season (austral summer, December 2021 to February 2022), while snow samples were taken from the remaining snow cover at the start of the season. The study area, underlain by the Llano Point and Zamek formations—comprised mainly of basalt and andesite—reveals significant geological contributions of elements such as Fe, Al and Mg due to active weathering processes amplified by glacial retreat. The research highlights how meteorological condition change-induced temperature and precipitation increases accelerate sediment erosion and weathering, mobilising metals and metalloids from glaciers and snowmelt. Significant concentrations of Cr, V and Ba in collected samples align with the local geological substratum. Statistical analyses (Kruskal–Wallis ANOVA) identified notable differences in Mo and Ba levels between glacier forefields, consistent with geological influences, as these elements occur in varying concentrations within the local basaltic and andesitic bedrock. Seasonal variations were also observed, particularly for Mg and K ions, indicating that meltwater dynamics influence element mobilisation throughout the season. Furthermore, Tower Glacier's eastward exposure explains the higher concentrations of Zn and Cd, suggesting atmospheric deposition as a contributing factor. This study underscores the complex interactions between geological, climatic and atmospheric processes, illustrating how geogenic sources and cryosphere degradation influence the chemical landscape of Antarctic glacier forefields

The effect of fungal proteolytic enzymes on myofibrillar proteins in dry-aged beef

The role of fungi in traditional food fermentation is not fully understood. The aim of this study was to assess the enzymatic potential of a fungal biostarter isolated from dry-aged beef. We have applied a multi-omics approach, i.e. combined the analysis of genomic and transcriptomic data with the observation of protein degradation patterns in the fungus-inoculated meat. Thanks to this, it was possible to pinpoint the enzymes produced by the fungus responsible for the changes occurring during dry-ageing. By comparing samples of meat inoculated with the fungal biostarter and those without, we were able to establish the effect of fungal enzymes on meat protein composition. The presence of the fungus on meat increased the relative amount of selected low-molecular-weight proteins (i.e.113.9 kDa, 103.5 kDa, and 18.9 kDa). We believe this change may be caused by fungal endopeptidase activity. Additionally, results of transcriptome analysis indicate that several aspartic endopeptidases were expressed by the fungus. The identified enzymes have a similar structure to the aspartic peptidases used as microbial rennets. Overall, the changes caused by the fungus during dry-ageing seem to be linked to the activity of released aspartic endopeptidases

Biometeorological conditions at Polish Antarctic station (King George Island, West Antarctica) according to Universal Thermal Climate Index, 2013–2023

The Universal Thermal Climate Index (UTCI) was used to estimate thermal stress for humans in the South Shetland Islands (West Antarctica), the region in Antarctica with the highest number of scientific stations and visiting tourists. This was done to analyze the duration of comfortable weather conditions, which are crucial for conducting fieldwork and other outdoor tasks. The UTCI is one of the most commonly used climate thermal indices, but it had not previously been calculated for any region in Antarctica. The research was based on hourly data (air temperature, humidity, global solar radiation and wind speed) derived from the Henryk Arctowski Polish Antarctic Station between 2013 and 2023. The range of hourly UTCI values indicates conditions ranging from no thermal stress to extreme cold stress, with predominant strong cold stress (–26.9 to − 13.0 °C; 40.5% of cases) and very strong cold stress (–39.9 to − 27.0 °C; 25.3% of cases). In such conditions, it is recommended that physical activity is increased and that the extremities and face are protected from the cold while working outside, as well as increasing the thermo-isolation properties of clothing. The same thermal stress class remains for more than one day sporadically. The most favourable conditions for spending time outside (without thermal stress or with slight cold stress), which lasted 7–9 consecutive hours, occurred rarely and only from December to March. Due to high wind speed, some UTCI values fall outside the thermal stress scale; nevertheless, the authors classified these as extreme cold stress and suggest developing the UTCI formula to make it more applicable in regions where very high wind speed occur

Functional and biosynthetic investigation of polyisoprenoids in roses leaves

Although terpenoids in roses have been extensively studied, the polyisoprenoid fraction has remained unexplored. In this work, we provide the first characterization of polyisoprenoid diversity and biosynthesis in roses, revealing unexpected chemical and enzymatic complexity. Four distinct polyisoprenoid families (7–9, 15–25, 26–34, and 35–50 isoprene units) were identified in Rosa chinensis, with very long-chain compounds accumulated in leaves and young shoots. We functionally characterized three cis-prenyltransferases (CPTs) and a CPT-binding partner, RcNUS1, involved in their biosynthesis. The chloroplast-localized RcCPT2 synthesizes short-chain polyisoprenoids, whereas two endoplasmic reticulum-localized heteromeric enzymes, RcCPT1 and RcCPT3, require RcNUS1 as a partner to produce longer-chain compounds. Phylogenetic analysis revealed strong evolutionary conservation but notable species-specific diversification of these enzymes. Remarkably, the number of polyisoprenoid families exceeded the number of identified CPTs, challenging the long-standing one-enzyme–one-product paradigm and suggesting additional, yet unidentified mechanisms regulating chain length. To explore their potential functions, we analyzed the effects of temperature, light, and leaf age on polyisoprenoid accumulation. Environmental treatment had little effect, but leaf aging caused a marked increase in long-chain polyisoprenoids, suggesting roles in development and physiological stability. Our findings reveal new aspects of polyisoprenoid metabolism and highlight their potential functional diversity in plants

Impact of plant-derived biochars on biohydrogen production from sugar beet molasses in a continuous system: insights into the roles of microbial communities and chemical elements.

Biochar shows great potential to enhance biohydrogen production via dark fermentation, but most studies have focused on short-term batch tests. This study investigates the impact of pine bark, coconut copra and cherry pit biochars in continuous bioreactors, integrating reactor performance, microbial community data and elemental analysis. Being richest in several biologically important elements, the coconut-derived biochar produces the most significant improvement in biohydrogen yield, from 2–3 to 45 dm³H₂/kg COD molasses. This correlates with an increased abundance of biohydrogen-producing microbial taxa and a 100-fold rise in hydA gene copies. Threefold-elevated butyrate and 33%-reduced lactate levels suggest stimulation of butyrate synthesis. However, this enhancement is temporary, requiring periodic biochar replacement and bioreactor reinoculation. Although biochar promotes biofilm formation, excessive growth may inhibit activity. Furthermore, it has little influence on pH buffering but effectively adsorbs toxic metals, e.g., chromium. Overall, coconut-derived biochar is a promising but short-lived enhancer of hydrogen fermentation

Gelidimonas denitrificans gen. nov., sp. nov., and Gelidimonas diazotrophica sp. nov. psychrophilic bacteria involved in the nitrogen cycle in tundra soils of South Spitsbergen

Two Gram-negative, psychrophilic, denitrifying bacterial strains, D2 and D11, were isolated from ornithogenic soil collected at a breeding colony of the marine bird Alle alle on Spitsbergen Island, Svalbard (Norway; High Arctic). Complete genome sequencing revealed that each strain possesses a single circular chromosome (3.83 Mbp and 3.63 Mbp, respectively) with similar GC content (55.3% and 55.5%), as well as plasmids – one shared by both strains (26.3 kb) and one unique to strain D11 (16.3 kb). Despite their striking genetic similarity, the two strains exhibit distinct physiological characteristics. Strain D2 is a facultative chemolithoautotroph capable of using hydrogen as an energy source and assimilating carbon dioxide and dinitrogen, whereas strain D11 displays a strictly heterotrophic lifestyle. Although the 16S rRNA genes of D2 and D11 share a high level of sequence identity (99.6%), whole-genome comparative analyses, including digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI), indicated that they represent two distinct species within the family Oxalobacteraceae (class Betaproteobacteria). Core proteome-based phylogenetic analysis of Oxalobacteraceae unambiguously placed both strains within the family; however, neither clustered with any currently described genus. We therefore propose that these strains represent a novel genus, Gelidimonas gen. nov., with type species Gelidimonas denitrificans sp. nov. (type strain D11T) and a second species Gelidimonas diazotrophica sp. nov. (type strain D2T)

Dissolving Silver Nanoparticles Modulate the Endothelial Monocyte-Activating Polypeptide II (EMAP II) by Partially Unfolding the Protein Leading to tRNA Binding Enhancement

Metal nanoparticles (NP) are increasingly used in biomedical applications. Among them, silver NPs (AgNPs) are used as active components in antibacterial coatings for wound dressings, medical devices, implants, cosmetics, textiles, and food packaging. On the other hand, AgNPs can be toxic to humans, depending on the dose and route of exposure, as agents delivering silver to cells. The cysteine residues are the primary molecular targets in such exposures, due to the high affinity of Ag+ ions to thiol groups. The Endothelial monocyte-activating polypeptide II (EMAP II), a cleaved C-terminal peptide of the intracellular aminoacyl-tRNA synthetase multifunctional protein AIMP1, contains five cysteines exposed at its surface. This prompted the question of whether they can be targeted by Ag+ ions present at the AgNPs surface or released from AgNPs in the course of oxidative metabolism of the cell. We explored the interactions between recombinant EMAP II, tRNA, and AgNPs using UV-Vis and fluorescence spectroscopy, providing insight into the effects of AgNPs dissolution kinetics on interaction EMAP II with tRNA. In addition, the EMAP II fragments binding to intact AgNPs were established by heteronuclear 1H-15N HSQC spectra utilizing a paramagnetic probe. Structural analysis of the EMAP II reveal that the 3D structure of protein was destabilized (partially denatured) by the binding of Ag+ ions released from AgNPs at the most exposed cysteines. Surprisingly, this effect enhanced tRNA affinity to EMAP II, lowering its Kd. The course of the EMAP II/tRNA/AgNP reaction was also modulated by other factors, such as the presence of Mg2+ ions and TCEP, a thiol-group protector used to mimic the reducing conditions of the cell

The Essential Rot1 Protein Links Glycosylation, Cell Wall Integrity, and Pathogenic Development in Candida albicans

The Rot1 protein is a chaperone involved in glycosylation, dolichol phosphorylation, cell wall synthesis, and protein folding in the yeast Saccharomyces cerevisiae. Available information on cell wall defects in the S. cerevisiae rot1-1 mutant and the association of Rot1 with protein glycosylation suggest that in the case of Candida albicans, Rot1 may be involved in pathogenesis, since both cell wall synthesis and protein glycosylation are closely related to the formation of pathogenic structures in C. albicans. As Rot1 has not been found in humans, it seems particularly attractive for study in the context of C. albicans pathogenicity. This protein takes on additional significance because deletion of the gene that encodes Rot1 is lethal for yeast. In this study, we cloned and analyzed the function of the candidate protein CaRot1 from C. albicans in the S. cerevisiae rot1∆/ROT1 mutant. Furthermore, we investigated the consequences of restricted CaROT1 expression in C. albicans. We have shown that a low amount of Rot1 limits the transfer of oligosaccharide to protein, inhibits the activity of the first steps of oligosaccharide formation on dolichyl diphosphate, changes the composition of the cell wall, limits the protection of C. albicans against ER and abiotic stress, and finally prevents filamentation, which is an invasive structure of C. albican

Molecular identification of cestodes from rodents in the Mazury Lake District region of Poland

Rodents serve as hosts for many species of parasites, including cestodes, but the taxonomy of rodent-infecting tapeworms, especially in Central Europe, is still understudied. Therefore, the current study was conducted to identify larval and adult cestodes in free-living rodents from Northeastern Poland. The fieldwork was conducted between 2014 and 2023 in three forest sites. Cestodes were collected from five rodent species (Clethrionomys glareolus, Alexandromys oeconomus, Microtus agrestis, Apodemus agrarius and A. flavicollis, and were identified through morphology and by several genetic markers (12S rDNA, cox1, nad 1, 28S rDNA, 12S-16S rDNA) using phylogenetic analyses. A total of 58 cestode specimens were analyzed using molecular and phylogenetic analyses. Species identified included Catenotaenia henttoneni, Spasskijela kratochvili, Mesocestoides litteratus, Mesocestoides melesi, and others. Three Paranoplocephala specimens were identified as P. kalelai based on nad1 sequences. Morphological and genetic analyses indicated that the dominant adult cestode in bank vole was C. henttoneni and Mesocestoides spp. were the dominant larval cestodes. This study combined genetic and morphological methods to identify the cestodes infecting rodents in Poland. It confirmed the existence of P. kalelai in Poland, suggesting that previously reported Paranoplocephala spp., identified by morphological characters, may have corresponded to this molecularly identified species. Our study also highlighted gaps in genetic databases that currently still do not allow precise species identification