Bacterial oxygen sensing embodies a fascinating interplay between evolutionary pressures and physiological adaptations to varying oxygen levels. Throughout Earth's history, the composition of the atmosphere has undergone significant changes, from anoxic conditions to the gradual accumulation of oxygen. In response, microbial life has evolved diverse strategies to cope with these shifting oxygen levels, ranging from anaerobic metabolism to oxygen-dependent pathways crucial for energy production and cellular processes typical for eukaryotic, multicellular organisms. Of particular interest is the role of iron in bacterial oxygen sensing systems, which play pivotal roles in adaptation to changing oxygen levels. Only free iron, heme-iron, and non-heme iron directly sense oxygen. These iron-containing proteins, such as heme-containing sensors and iron-sulfur cluster proteins, regulate the expression of genes and activity of enzymes involved in oxidative stress defence, virulence, and biofilm formation, highlighting their significance in bacterial pathogenesis and environmental adaptation. Special attention in the review is paid to the mechanisms of oxygen detection and signal transduction from heme-containing sensing to functional domains in the case of bacterial heme-based oxygen sensors.

• Klíčová slova
• Heme-based sensor, Intramolecular catalytic regulation, Oxygen sensing, Signal transduction,
• MeSH
• Bacteria * metabolismus   genetika   MeSH
• bakteriální proteiny metabolismus   genetika   MeSH
• fyziologie bakterií * MeSH
• hem * metabolismus   MeSH
• hemoproteiny metabolismus   MeSH
• kyslík * metabolismus   MeSH
• regulace genové exprese u bakterií MeSH
• signální transdukce MeSH
• železo * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• bakteriální proteiny MeSH
• hem * MeSH
• hemoproteiny MeSH
• kyslík * MeSH
• železo * MeSH

Phytic acid is the main storage of phosphate in grains of staple crops. As phytic acid is hardly digestible for non-ruminants microbial phytases are used to supplement animal feed to enhance phosphate digestibility. A fungal phytase gene was introduced into barley with the aim of enhancing phosphate digestibility. Transgenic homozygous barley over-expressing fungal phytase phyA showed a 3.3fold increase in mature grain phytase activity. Field trials at two locations in the Czech Republic were conducted in a five-year experiment to test transgene stability and activity under field conditions. Increased phytase activity gradually decreased over the generations showing the most significant drop in the initial years of field trials. Molecular analysis revealed methylation in the coding sequence of the phyA transgene, suggesting transcription gene silencing. On the other hand, herbicide resistance used for selection of transgenic plants was functional over all generations. The feasibility of crossing the transgene into the feeding cultivar Azit was demonstrated with subsequent stabilization of hybrid progeny through androgenesis. Our results indicate that the Azit genetic background tended to reduce phytase activity in mature grains of hybrids. Grain-specific over-expression of fungal phytase driven by an amylase promoter improved phosphate levels during germination. Unfortunately, a malting experiment revealed that phytase over-expression did not significantly improve malting parameters. In fact, the higher nitrogen content in unmalted grain negatively affected the quality of the malt produced from them.

• Klíčová slova
• Transgenic barley, androgenesis, field trials, hybridization, phytase,
• MeSH
• 6-fytasa * genetika   metabolismus   MeSH
• Aspergillus niger * enzymologie   genetika   MeSH
• fosfáty metabolismus   MeSH
• fungální proteiny * genetika   metabolismus   MeSH
• geneticky modifikované rostliny * genetika   metabolismus   MeSH
• ječmen (rod) * genetika   enzymologie   metabolismus   MeSH
• kyselina fytová metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 6-fytasa * MeSH
• fosfáty MeSH
• fungální proteiny * MeSH
• kyselina fytová MeSH

Inbred mouse strains provide phenotypic homogeneity between individual mice. However, stochastic morphogenetic events combined with epigenetic changes due to exposure to environmental factors and ontogenic experience result in variability among mice with virtually identical genotypes, reducing the reproducibility of experimental mouse models. Here we used microscopic and cytometric techniques to identify individual patterns in gut-associated lymphoid tissue (GALT) that are induced by exposure to microbiota. By comparing germ-free (GF), conventional (CV) and gnotobiotic mice colonized with a defined minimal mouse microbiota (oMM12) MHC II-EGFP knock-in mice we quantified antigen-presenting cells (APCs) in the lamina propria, cryptopatches (CP), isolated lymphoid follicles (ILFs), Peyer's patches (PPs) and specific sections of the mesenteric lymphoid complex. We found that GF mice had a significantly larger outer intestinal surface area compared to CV and oMM12-colonized mice, which partially compensated for their lower density of the villi in the distal ileum. GF mice also contained fewer APCs than oMM12 mice in the Iamina propria of the villi and had a significantly smaller volume of the solitary intestinal lymphoid tissue (SILT). In both GF and oMM12 mice, PP follicles were significantly smaller compared to CV mice, although number was similar. Concomitantly, the number of pDCs in PPs was significantly lower in GF mice than in CV mice. Moreover, the cecal patch was dispersed into small units in GF mice whereas it was compact in CV mice. Taken together, we here provide further evidence that microbiota regulates SILT differentiation, the size and morphology of PPs, the cellular composition of mesenteric lymph nodes (MLNs) and the morphology of cecal patch. As such, microbiota directly affect not only the functional configuration of the immune system but also the differentiation of lymphoid structures. These findings highlight how standardized microbiota, such as oMM12, can promote reproducibility in animal studies by enabling microbiologically controlled experiments across laboratories.

• Klíčová slova
• Germ-free and gnotobiotic models, Gut-associated lymphoid tissue (GALT), Lymphoid tissue morphogenesis, MHCII-EGFP knock-in mice, Microbiota-induced immunity, Phenotypic plasticity,
• MeSH
• antigen prezentující buňky imunologie   MeSH
• gnotobiologické modely MeSH
• lymfoidní tkáň * imunologie   cytologie   mikrobiologie   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• Peyerovy pláty imunologie   cytologie   MeSH
• střevní mikroflóra * imunologie   MeSH
• střevní sliznice imunologie   mikrobiologie   cytologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVES: To analyse characteristics of Clostridioides difficile PCR ribotype 176 clinical isolates from Poland, the Czech Republic and Slovakia with regard to the differences in its epidemiology. METHODS: Antimicrobial susceptibility testing and whole genome sequencing were performed on a selected group of 22 clonally related isolates as determined by multilocus variable-number tandem repeat analysis (n = 509). Heterologous expression and functional analysis of the newly identified methyltransferase were performed. RESULTS: Core genome multilocus sequence typing found 10-37 allele differences. All isolates were resistant to fluoroquinolones (gyrA_p. T82I), aminoglycosides with aac(6')-Ie-aph(2'')-Ia in six isolates. Erythromycin resistance was detected in 21/22 isolates and 15 were also resistant to clindamycin with ermB gene. Fourteen isolates were resistant to rifampicin with rpoB_p. R505K or p. R505K/H502N, and five to imipenem with pbp1_p. P491L and pbp3_p. N537K. PnimBG together with nimB_p. L155I were detected in all isolates but only five were resistant to metronidazole on chocolate agar. The cfrE, vanZ1 and cat-like genes were not associated with linezolid, teicoplanin and chloramphenicol resistance, respectively. The genome comparison identified six transposons carrying antimicrobial resistance genes. The ermB gene was carried by new Tn7808, Tn6189 and Tn6218-like. The aac(6')-Ie-aph(2'')-Ia were carried by Tn6218-like and new Tn7806 together with cfrE gene. New Tn7807 carried a cat-like gene. Tn6110 and new Tn7806 contained an RlmN-type 23S rRNA methyltransferase, designated MrmA, associated with high-level macrolide resistance in isolates without ermB gene. CONCLUSIONS: Multidrug-resistant C. difficile PCR ribotype 176 isolates carry already described and unique transposons. A novel mechanism for erythromycin resistance in C. difficile was identified.

• Klíčová slova
• Clostridioides difficile infection, epidemiology, macrolide resistance methyltransferase, whole genome sequencing,
• MeSH
• antibakteriální látky * farmakologie   MeSH
• bakteriální léková rezistence * MeSH
• bakteriální proteiny genetika   MeSH
• Clostridioides difficile * genetika   účinky léků   izolace a purifikace   klasifikace   MeSH
• genomové ostrovy * MeSH
• klostridiové infekce * mikrobiologie   epidemiologie   MeSH
• lidé MeSH
• methyltransferasy genetika   MeSH
• mikrobiální testy citlivosti MeSH
• mnohočetná bakteriální léková rezistence * genetika   MeSH
• multilokusová sekvenční typizace MeSH
• ribotypizace MeSH
• sekvenování celého genomu MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Polsko epidemiologie   MeSH
• Názvy látek
• antibakteriální látky * MeSH
• bakteriální proteiny MeSH
• methyltransferasy MeSH

Super- and low-shedding phenomena have been observed in genetically homogeneous hosts infected by a single bacterial strain. To decipher the mechanisms underlying these phenotypes, we conducted an experiment with chicks infected with Salmonella Enteritidis in a non-sterile isolator, which prevents bacterial transmission between animals while allowing the development of the gut microbiota. We investigated the impact of four commensal bacteria called Mix4, inoculated at hatching, on chicken systemic immune response and intestinal microbiota composition and functions, before and after Salmonella infection. Our results revealed that these phenotypes were not linked to changes in cell invasion capacity of bacteria during infection. Mix4 inoculation had both short- and long-term effects on immune response and microbiota and promoted the low-shedder phenotype. Kinetic analysis revealed that Mix4 activated immune response from day 4, which modified the microbiota on day 6. This change promotes a more fermentative microbiota, using the aromatic compounds degradation pathway, which inhibited Salmonella colonization by day 11 and beyond. In contrast, control animals exhibited a delayed TNF-driven pro-inflammatory response and developed a microbiota using anaerobic respiration, which facilitates Salmonella colonization and growth. This strategy offers promising opportunities to strengthen the barrier effect against Salmonella and possibly other pathogens.

• Klíčová slova
• Salmonella, carrier-state, chicken, excretion, immune response, microbiota, super-shedder, virulence,
• MeSH
• Bacteria * imunologie   klasifikace   genetika   MeSH
• kur domácí imunologie   mikrobiologie   MeSH
• nemoci drůbeže * mikrobiologie   imunologie   prevence a kontrola   MeSH
• Salmonella enteritidis * imunologie   růst a vývoj   fyziologie   MeSH
• salmonelová infekce u zvířat * imunologie   mikrobiologie   prevence a kontrola   MeSH
• střevní mikroflóra * imunologie   MeSH
• symbióza MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Plant materials that have been in contact with pesticides can be incorporated into the soil, posing a potential risk to non-target soil organisms and, hence, soil functions. This study investigated effects of two pesticides applied to maize leaves on the soil microbial community, activity and function. The herbicide prosulfocarb (PSC) and the fungicide boscalid (BSC) were applied alone or in combination to fresh or aged maize leaves, which were incorporated into soil. During a 56-day incubation we quantified pesticide residues in soil and maize leaves as well as maize-derived C incorporation into different microbial fractions (CO2, extractable organic carbon, microbial biomass and main microbial groups). Prosulfocarb residues on maize and in soil decreased to below 5 % after 56 days. However, BSC residues were transferred from maize into the soil, as indicated by an increase in BSC residues in soil of around 15 %. Prosulfocarb initially inhibited the synthesis of soil bacterial phospholipids by 25-45 %, which was accompanied by a decrease in the incorporation of maize-derived C into microbial biomass by 68-70 %. Following this, microorganisms shifted their nutrient acquisition strategy towards carbon and phosphorus, which led to increased utilization of easily available maize-derived C. Boscalid transiently inhibited the growth of soil fungi, reduced soil respiration, and mineralization of maize. In the future, pesticide accumulation through transfer from plant material into soils and the mode of action dependent effects on soil microorganisms need to be considered for risk assessment.

• Klíčová slova
• (13)C PLFA, Mode of action, Pesticide mixtures, SPRINT project, Soil enzymes, Substrate quality,
• MeSH
• bifenylové sloučeniny MeSH
• herbicidy * analýza   toxicita   metabolismus   MeSH
• karbamáty * analýza   metabolismus   toxicita   MeSH
• kukuřice setá * chemie   metabolismus   MeSH
• látky znečišťující půdu * analýza   toxicita   metabolismus   MeSH
• listy rostlin chemie   metabolismus   MeSH
• niacinamid analogy a deriváty   MeSH
• nitrily * analýza   metabolismus   toxicita   MeSH
• průmyslové fungicidy * analýza   toxicita   metabolismus   MeSH
• půda chemie   MeSH
• půdní mikrobiologie * MeSH
• rezidua pesticidů * analýza   toxicita   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 2-chloro-N-(4-chlorobiphenyl-2-yl)nicotinamide MeSH Prohlížeč
• bifenylové sloučeniny MeSH
• herbicidy * MeSH
• karbamáty * MeSH
• látky znečišťující půdu * MeSH
• niacinamid MeSH
• nitrily * MeSH
• průmyslové fungicidy * MeSH
• půda MeSH
• rezidua pesticidů * MeSH

Biological diversity in mountain ecosystems has been increasingly studied over the last decade. This is also the case for mountain soils, but no study to date has provided an overall synthesis of the current state of knowledge. Here we fill this gap with a first global analysis of published research on cryptogams, microorganisms, and fauna in mountain soils above the treeline, and a structured synthesis of current knowledge. Based on a corpus of almost 1400 publications and the expertise of 37 mountain soil scientists worldwide, we summarise what is known about the diversity and distribution patterns of each of these organismal groups, specifically along elevation, and provide an overview of available knowledge on the drivers explaining these patterns and their changes. In particular, we document an elevation-dependent decrease in faunal diversity above the treeline, while for cryptogams there is an initial increase above the treeline, followed by a decrease towards the nival belt. Thus, our data confirm the key role that elevation plays in shaping the biodiversity and distribution of these organisms in mountain soils. The response of prokaryote diversity to elevation, in turn, was more diverse, whereas fungal diversity appeared to be substantially influenced by plants. As far as available, we describe key characteristics, adaptations, and functions of mountain soil species, and despite a lack of ecological information about the uncultivated majority of prokaryotes, fungi, and protists, we illustrate the remarkable and unique diversity of life forms and life histories encountered in alpine mountain soils. By applying rule- as well as pattern-based literature-mining approaches and semi-quantitative analyses, we identified hotspots of mountain soil research in the European Alps and Central Asia and revealed significant gaps in taxonomic coverage, particularly among biocrusts, soil protists, and soil fauna. We further report thematic priorities for research on mountain soil biodiversity above the treeline and identify unanswered research questions. Building upon the outcomes of this synthesis, we conclude with a set of research opportunities for mountain soil biodiversity research worldwide. Soils in mountain ecosystems above the treeline fulfil critical functions and make essential contributions to life on land. Accordingly, seizing these opportunities and closing knowledge gaps appears crucial to enable science-based decision making in mountain regions and formulating laws and guidelines in support of mountain soil biodiversity conservation targets.

• Klíčová slova
• alpine soils, bacteria, biogeography, cryptogams, fungi, invertebrates, lichens, microbial diversity, protists, systematic mapping,
• MeSH
• Bacteria klasifikace   MeSH
• biodiverzita * MeSH
• nadmořská výška * MeSH
• půda * MeSH
• půdní mikrobiologie * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• půda * MeSH

Molasses stillage, with its high organic content and nutrient-rich composition, represents a promising feedstock for biogas production. This study systematically evaluated its biochemical methane potential (BMP) using two inocula (wastewater treatment plant vs agricultural biogas plant) across three temperatures (40, 50, 60 °C) and initial substrate load (ISL: 2, 5, 10 g·Lincolum -1). The wastewater inoculum achieved superior methane yields (0.262-0.477 N m3·kgvs -1), peaking at 50 °C with a 22% increase over agricultural systems (0.192-0.378 N m3·kgvs -1). 16S rRNA sequencing revealed the wastewater treatment plant inoculum's superior functional diversity, dominated by syntrophic Chloroflexota and Acidobacteriota alongside methanogenic Methanobacterium (52-61% relative abundance) and acetoclastic Methanothrix (18-23%). In contrast, agricultural biogas plant inocula showed specialized thermophilic communities dominated by Bacillota (68-72%) and hydrogenotrophic Methanoculleus (29-34%). Both systems exhibited inhibition at 60 °C/ISL10 (yields reduced by 34-42%), correlating with declining diversity and Methanofastidiosum proliferation. These findings provide two key operational insights: wastewater inocula offer greater process stability due to microbial diversity, and 50 °C represents the thermal optimum for stillage codigestion, balancing yield and community resilience.

• Publikační typ
• časopisecké články MeSH

Rhizophora species are ecologically significant true mangroves with a broad tropical distribution. We examined the rhizospheric microbiomes of dominant Rhizophora species from two contrasting Indian mangrove ecosystems-Coringa and Pichavaram-using high-throughput metabarcoding. Soil properties differed significantly between sites: Pichavaram exhibited higher electrical conductivity (24.53 dS/m), organic carbon (1.70%), sodium (8811.86 ppm), sodium adsorption ratio (220.15), and exchangeable sodium percentage (64.27%), while Coringa soils showed higher pH (8.01). Sequencing generated 1.31, 1.24, and 1.22 million high-quality reads for archaea, bacteria, and fungi, respectively. Taxonomic profiling revealed Nitrososphaeria (62.3-91.9%), Gammaproteobacteria (16.8-25.1%), and Sordariomycetes (18.6-27.8%) as dominant classes. Core taxa across both sites included Candidatus Nitrosopumilus, Woeseia, and Aspergillus. Alpha diversity indices (Chao1, Shannon, Simpson) indicated significantly higher bacterial richness and evenness in R. apiculata at Coringa (P < 0.001), while archaeal and fungal diversity showed no marked differences. Beta diversity analysis (PCoA, PERMANOVA) revealed distinct community compositions between Coringa and Pichavaram, with stronger segregation in archaeal and bacterial assemblages than in fungi. Differential abundance analysis identified nine archaeal, fifty-nine bacterial, and three fungal genera enriched between sites, with methanogens (Methanosarcina, Methanocella) predominant in Coringa and halophiles (Halococcus, Haloferax) in Pichavaram. Redundancy analysis showed sodium adsorption ratio as the key determinant of microbial assemblages, while electrical conductivity significantly shaped archaeal and fungal communities. These findings provide the first baseline dataset of the Coringa rhizospheric microbiome and new insights into the microbial ecology of Indian mangroves, with implications for ecosystem functioning, methane emissions, and conservation strategies.

• Klíčová slova
• Coringa, Mangroves, Microbiome, Pichavaram, Rhizosphere, Salinity,
• Publikační typ
• časopisecké články MeSH

Spiders serve as key biological control agents in agroecosystems, but they face repeated disturbances due to common agricultural practices. The wolf spider Pardosa agrestis, a dominant agrobiont species, recolonizes these disrupted habitats via dispersal strategies such as ballooning, particularly during juvenile stages. This study investigated how nutrition and insecticide exposure influence ballooning behavior and the structure-function dynamics of the spider's tissue-resident microbiome. We found that dispersal behavior in P. agrestis is structured and repeatable, driven by environmental cues such as light and wind, and further modulated by previous exposure. Although diet significantly impacted growth and development, it had a minimal influence on the dispersal strategy. The tissue-resident microbiome analysis revealed a diverse, core symbiotic community with notable responsiveness to both dietary and pesticide-induced stress. Specific tissue-resident microbial taxa shifted their predicted metabolic output under nutrient deprivation, suggesting adaptive biosynthetic activity. Importantly, distinct predicted microbial metabolic profiles were associated with spider behaviors (e.g., ballooning) and physiological traits (e.g., endurance), indicating a microbiome-mediated influence on the dispersal capacity. Moreover, tissue-resident microbial community function was correlated with host survival after insecticide exposure, implicating its role in detoxification and resistance. These findings highlight the role of the tissue-resident microbiome as a functional partner in arthropod stress resilience and dispersal behavior in agroecosystems.

• Klíčová slova
• Ballooning behavior, Insecticide tolerance, Microbiome-mediated detoxification, Spider dispersal, Starvation response, Tissue-resident microbiome,
• Publikační typ
• časopisecké články MeSH