University of South Bohemia in České Budějovice

Aging is accompanied by progressive physiological declines in body functions. However, the molecular mechanisms of aging remain poorly understood in decapod crustaceans, a diverse group of invertebrates. We investigated age-related differences in the hemolymph proteomes of marbled crayfish using label-free protein quantification (LC-MS/MS), applying a significance threshold of p<0.05 and a fold change >2 to elucidate molecular mechanisms underpinning aging. Two groups including young (n=6) and old (n=7) crayfish were used. Results showed a downregulation of superoxide dismutase in the hemolymph of older individuals. At the same time, glutathione peroxidase and transketolase were upregulated, which may reflect age-dependent changes in oxidative stress regulation and potential compensatory responses. Aging crayfish exhibited changes in levels of the ProPO system and phagocytosis-related proteins that suggest a possible shift from melanization to phagocytosis in the aging immune system. Additionally, the lower levels of some other immune-related proteins in the old individuals may be consistent with a decline in the crayfish immune system with age. Proteins associated with wound healing and regeneration were higher in young individuals, which may suggest an age-based decline in regenerative capacity. Cytoskeletal and extracellular matrix proteins were upregulated in older crayfish, which could potentially influence immune cell functions. Age-related alterations in the quantities of vitellogenins, hemocyanins, and metabolic enzymes maybe associated with changes in reproductive investment, respiratory capacity, and energy metabolism. Together, these findings highlight the complex molecular basis by which aging reshapes the hemolymph composition and alters immune system characteristics in an invertebrate, revealing molecular signatures that may represent aging mechanisms. Data are available via ProteomeXchange with identifier PXD065434.

The context of armed conflict situations presents unique challenges that can compromise the safety and well-being of both affected populations and responders in radiological and nuclear emergencies. The focus of the EU project RRADEW 'Resilience to RADiological Events in Wartime'(2024-2027) is to enhance nuclear Emergency Preparedness, Response and Recovery (EPR&R) systems by strengthening resilience to potential incidents in the context of war or armed conflict. The project is structured in five work packages focusing on the development of war scenarios (WP1), identification of resilience dimensions and indicators (WP2 and 3), development of decision-support, training materials and recommendations targeting key stakeholders (WP4), and key ethical questions for radiological protection in the context of armed conflicts (WP5). Since its start in 2024 the project has built a war-risk scenario matrix for nuclear facilities, produced a resilience framework that links the Sendai-definition of resilience to radiation emergencies, integrating social, technical and organisational dimensions across the EPR&R system, drafted training modules for deminers and first-responder monitors and produced an ethical matrix highlighting dilemmas such as dignity, autonomy and justice in armed-conflict radiological events. Together, these efforts aim to provide actionable frameworks and recommendations to ensure the safety and well-being of both affected populations and responders in wartime radiological incidents.

The mitochondrial FoF1-ATP synthase is a reversible nanomachine that normally produces ATP via oxidative phosphorylation but under stress conditions it can reverse to maintain the mitochondrial membrane potential at the expense of ATP, a process regulated by the conserved inhibitory factor 1 (IF1). We show that ATP synthase reversal also occurs during in vitro-induced differentiation of the unicellular parasite Trypanosoma brucei, partially mirroring events in the tsetse fly. Differentiation of insect forms is marked by increased expression of alternative oxidase and reduced levels of trypanosomal IF1 (TbIF1), changes that may promote ATP synthase reversal. Parasites lacking TbIF1 efficiently progressed to the mammalian-infective form, coinciding with increased ATP synthase reversal, a higher ADP/ATP ratio, elevated phosphorylation of AMP-activated protein kinase (AMPK), enhanced proline-supported respiration, and increased mitochondrial and cellular reactive oxygen species (ROS). In contrast, inducible TbIF1 overexpression diminished these hallmarks and locked parasites in the initial insect stage. Our findings reveal that TbIF1 downregulation enables life cycle progression and underscore a regulatory role for the ATP synthase-IF1 axis.

ABSTRACT Methanotrophic bacteria oxidise large amounts of biogenic methane produced in freshwater and bind the original methane carbon in their biomass. When these bacteria are consumed by other organisms, methane‐derived carbon enters food webs. Methane‐derived carbon can support a substantial part of invertebrate biomass in some freshwater ecosystems. However, the transfer of methanogenic carbon further up the food web to higher‐level consumers has rarely been studied. Here, we used stable isotopes and mixing models to investigate the quantitative contribution of methane‐derived carbon to fish consumers in a deep and eutrophic reservoir, the Římov Reservoir, Czechia. We measured δ 13 C and δ 15 N in the five most abundant fish species, bleak ( Alburnus alburnus ), bream ( Abramis brama ), roach ( Rutilus rutilus ), perch ( Perca fluviatilis ) and ruffe ( Gymnocephalus cernua ), and their potential food sources, such as littoral macroinvertebrates, pelagic zooplankton, and profundal chironomid larvae. We expected that profundal chironomids would be the main agents for transferring methane carbon to higher‐level consumers, and thus we predicted that fish species better adapted to foraging in the profundal zone, such as bream and ruffe, would assimilate more methane‐derived carbon. The isotope values of littoral macroinvertebrates and pelagic zooplankton were too high to suggest any significant incorporation of methane‐derived carbon. In contrast, both the δ 13 C and δ 15 N values of profundal chironomids were very low. The results from an isotope mixing model considering methanotrophic bacteria and sedimentary organic carbon as sources indicated that profundal chironomids obtained 35%–71% of their carbon biomass from methane. Using these outcomes and the contributions of profundal prey to the five fish species, we estimated that the population carbon biomass derived from methane ranged from 0.2%–0.5% for perch to 4.2%–8.6% for ruffe. In line with our predictions, we found that bream and especially ruffe contained more methane‐derived carbon than the other fish species. We concluded that 2.2% of the total fish carbon in the Římov Reservoir could have come from biogenic methane. Our results suggest that partial support of fish communities in eutrophic lentic waters by methane‐derived carbon may be a common but hitherto overlooked phenomenon.

Peatlands are globally important sources and sinks of methane (CH4), yet the extent to which land-use change alters the balance between methanogenesis and methane oxidation across peatland types remains poorly constrained. Here, we quantify potential methane production and aerobic methane oxidation across 27 peatland sites within the EU Biodiversa+ project network, spanning Estonia, Finland, Germany, and Czechia and encompassing pristine, drained, and rewetted bogs and fens.We combined laboratory incubation assays with molecular approaches to assess methane cycling potential in both the aerobic peat layer and below the water table. Potential CH4 production and oxidation rates were measured under controlled conditions, alongside quantitative PCR targeting methanogenic (mcrA), methanotrophic (pmoA), and total bacterial (16S rRNA) genes. Shotgun metagenomics and 16S rRNA gene sequencing were used to explore the genomic potential for methane oxidation and to identify microbial taxa involved.Preliminary results indicate that pristine peatlands exhibit the highest potential rates of both methane production and oxidation. Drained sites show strongly reduced methanogenic potential, while rewetted sites display partial recovery, with rates generally remaining lower than in pristine systems. Higher methane oxidation rates in long-term rewetted sites (&gt;15 years) suggest that functional recovery may increase with time since rewetting. When separated by peatland type, bogs show higher methane cycling potentials than fens across all land-use categories.Pristine peatlands consistently showed highest methanogen gene abundances compared to rewetted and drained, particularly in the anaerobic peat layer. Methanotrophic gene abundances were highest in pristine peatlands in the aerobic layer; however, anaerobic layers of rewetted and drained peatlands harbored higher methanotrophic communities than in their aerobic layers. This suggests that methanotrophic communities in managed peatlands may establish deeper in the peat profile, potentially in response to oxygenic microsites or dynamic redox conditions. In rewetted and drained sites, pmoA gene abundance explained ~20% of the variation in methane oxidation rates, and mcrA explained ~10% in rewetted sites.Overall, these findings suggest that drainage substantially suppresses methanogenic potential, while rewetting promotes partial functional recovery, particularly in bog systems and on timescales of at least decades. Integrating process-based and molecular data provides new insight into how land-use change shapes peatland methane cycling.

In many regions on Earth, past and current changes in temperature, rainfall patterns, and snow cover are concomitant with changes in atmospheric pollution, probably causing interactive but overlooked impacts on ecosystems. However, in global-change ecology, we often study the interactive effects of climate changes (mainly temperature warming) and chemical pollution experimentally at short spatio-temporal scales and in controlled conditions. As a result, how these global change factors interact to shape long-term population dynamics in natural ecosystems, remains little known. As a key example, the European Black Triangle — the region at the borders of former Czechoslovakia, Germany, and Poland — was heavily air polluted in the 1970s and 1980s due to emissions from coal power plants, resulting in high loads of toxic element deposition (e.g., lead). In the Ore Mountains, within the Black Triangle region, we collected during 40 years (twice a year in June and October) the abundances of six small-mammal species belonging to three trophic guilds (omnivores, insectivores, and herbivores). We complemented this dataset with atmospheric pollution (SO₂, NOx, and total Particulate Matter), temperature, snow cover, and runoff (snowmelt and rainfall) historical data. Firstly, we studied the local stability (Lyapunov local stability) of the global change factors and small-mammal multivariate time series, respectively, and identified that periods of instability in climate and atmospheric pollution were preceding periods of small-mammal assemblage instability. Secondly, we used Bayesian Multivariate (Dynamic) Generalized Additive Models (MDGAMs) to test contrasting hypotheses on how different climate factors (snow cover, runoff, and temperature) may interact with temporal changes in pollution in a trophic-guild-specific manner. We showed evidence for guild-specific effects of climatic variables and atmospheric pollution. For instance, the strength of the negative interaction between runoff and atmospheric pollution on population dynamics depended on the trophic guild, with stronger negative effects on omnivores. We finish by discussing the implications of our findings on how global change factors contribute to community dynamics, and what this entails for species coexistence and biodiversity conservation amid ongoing changes in climate and atmospheric chemical composition.