Microbial community composition (cyanobacteria and eukaryotic microalgae abundance and diversity, bacterial abundance, and soil respiration) was studied in subglacial and periglacial habitats on five glaciers near Ny-Alesund, Svalbard (79 degrees N). Soil microbial communities from nonvegetated sites (subglacial, recently deglaciated, and cryoconite sediments) and sites with plant cover (deglaciated some hundreds of years ago) were analyzed. Physicochemical analyses (pH, texture, water content, organic matter, total C and N content) were also performed on the samples. In total, 57 taxa of 23 genera of cyanobacteriaand algae were identified. Algae from the class Chlorophyceae (25 species) and cyanobacteria (23 species) were richest in biodiversity. The numbers of identified species in single habitat types were 23 in subglacial, 39 inbarren, 22 in cryoconite, and 24 in vegetated soils. The highest cyanobacterial and algal biovolume and cell numbers, respectively, were present in cryoconite (13x10(4) microm3 mg-1 soil and 508 cells per mg of soil), followed by barren (5.7x10(4) and 188), vegetated (2.6x10(4) and 120), and subglacial (0.1x10(4) and 5) soils. Cyanobacteria prevailed in all soil samples. Algae (mainly green algae) were present only as accessory organisms. The density of bacteria showed a slightly different trend to that of the cyanobacterial and algal assemblages. The highest number of bacteria was present in vegetated (mean: 13,722x10(8) cells per mg of soil dry wt.), followed by cryoconite (3802x10(8)), barren (654x10(8)), and subglacial (78x10(8)) soils. Response of cyanobacteria and algae to physical parameters showed that soil texture and water content are important for biomass development. In addition, it is shown that nitrogen and water content are the main factors affecting bacterial abundance and overall soil respiration. Redundancy analysis (RDA) with forward selection was used to create a model explaining variability in cyanobacterial, algal, and bacterial abundance. Cryoconites accounted for most of the variation in cyanobacteria and algae biovolume, followed by barren soils. Oscillatoriales, desmids, and green coccoid algae preferred cryoconites, whereas Nostocales and Chroococcales occurred mostly in barren soils. From the data obtained, it is evident that of the studied habitats cryoconite sediments are the most suitable ones for the development of microbial assemblages. Although subglacial sediments do not provide as good conditions as cryoconites, they support the survival of microbial communities. Both mentioned habitats are potential sources for the microbial recolonization of freshly deglaciated soil after the glacier retreat.

• MeSH
• Chlorophyta izolace a purifikace   MeSH
• ekosystém MeSH
• Eukaryota klasifikace   izolace a purifikace   MeSH
• led MeSH
• počet mikrobiálních kolonií MeSH
• půda analýza   MeSH
• půdní mikrobiologie * MeSH
• sinice klasifikace   izolace a purifikace   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Geografické názvy
• Arktida MeSH
• Názvy látek
• led MeSH
• půda MeSH

Few studies have evaluated the trophic level in tropical caves, and none related the microbial biomass dynamics in the immobilization of carbon and nitrogen. Here, four tropical caves of Terra Ronca State Park, Brazil, were studied: Angélica, São Bernardo, Terra Ronca I, and Terra Ronca II caves. Physical, chemical, and microbiological parameters (microbial biomass and respiration) were estimated in the dry and wet seasons. São Bernardo, Terra Ronca I, and Terra Ronca II caves presented higher nitrogen and microbial biomass nitrogen (MBN) values in the wet season than in the dry season. On the other hand, the Angélica cave showed larger amounts of nitrogen and lower MBN values in the dry season. These results indicate that caves can be adjusted in two ecological theories known as "stoichiometric decomposition" and "microbial nitrogen mining"-to the effects of nutrient availability on organic matter decomposition. The caves studied showed different environmental dynamics in relation to organic matter decomposition, which allows them to be considered unique and possess specific characteristics. Microbial biomass dynamics can be an important parameter to evaluate the availability of nutrients and ecological dynamics of the trophic network in subterranean environments.

• Klíčová slova
• Brazil, decomposition, microbial parameters, organic matter, subterranean environment,
• MeSH
• Bacteria růst a vývoj   metabolismus   MeSH
• biomasa MeSH
• dusík analýza   MeSH
• jeskyně chemie   mikrobiologie   MeSH
• půda chemie   MeSH
• půdní mikrobiologie MeSH
• uhlík analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Brazílie MeSH
• Názvy látek
• dusík MeSH
• půda MeSH
• uhlík MeSH

Biocrusts are crucial components of Arctic ecosystems, playing significant roles in carbon and nitrogen cycling, especially in regions where plant growth is limited. However, the microbial communities within Arctic biocrusts and their strategies for surviving the harsh conditions remain poorly understood. In this study, the microbial profiles of Arctic biocrusts across different seasons (summer, autumn, and winter) were investigated in order to elucidate their survival strategies in extreme conditions. Metagenomic and metatranscriptomic analyses revealed significant differences in microbial community composition among the sites located in different elevations. The bacterial communities were dominated by Actinobacteria and Proteobacteria, while the fungal communities were mainly represented by Ascomycota and Basidiomycota, with lichenized and saprotrophic traits prevailing. Cyanobacteria were primarily composed of heterocystous cyanobacteria. Furthermore, the study identified molecular mechanisms underlying cold adaptation, including the expression of heat shock proteins and cold-inducible RNA helicases in cyanobacteria and fungi. Overall, the microbial communities appear to be permanently well adapted to the extreme environment.

• Klíčová slova
• Cold adaptation, Environmental parameters, Meta-omics, Polar, Seasons, soil microbial communities,
• MeSH
• ekosystém MeSH
• houby * genetika   klasifikace   MeSH
• mikrobiota * MeSH
• roční období * MeSH
• sinice * genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Arktida MeSH

In the past few decades, the pressure of higher food production to satisfy the demand of ever rising population has inevitably increased the use synthetic agrochemicals which have deterioration effects. Biostimulants containing beneficial microbes (single inoculants and microbial consortium) were found as an ideal substitute of synthetic chemical fertilizers. In recent years, microbial consortium is known as a better bioinoculant in comparison to single inoculant bioformulation because of multifarious plant growth-promoting advantages. Looking at the advantageous effect of consortium, in present investigation, different bacteria were isolated from rhizospheric soil and plant samples collected from the Himalayan mountains on the green slopes of the Shivaliks, Himachal Pradesh. The isolated bacteria were screened for nitrogen (N) fixation, phosphorus (P) solubilization and potassium (K) solubilization plant growth promoting attributes, and efficient strains were identified through 16S rRNA gene sequencing and BLASTn analysis. The bacteria showing a positive effect in NPK uptake were developed as bacterial consortium for the growth promotion of eggplant crop. A total of 188 rhizospheric and endophytic bacteria were sorted out, among which 13 were exhibiting nitrogenase activity, whereas 43 and 31 were exhibiting P and K solubilization traits, respectively. The selected three efficient and potential bacterial strains were identified using 16S rRNA gene sequencing as Enterobacter ludwigii EU-BEN-22 (N-fixer; 35.68 ± 00.9 nmol C2H4 per mg protein per h), Micrococcus indicus EU-BRP-6 (P-solubilizer; 201 ± 0.004 mg/L), and Pseudomonas gessardii EU-BRK-55 (K-solubilizer; 51.3 ± 1.7 mg/mL), and they were used to develop a bacterial consortium. The bacterial consortium evaluation on eggplant resulted in the improvement of growth (root/shoot length and biomass) and physiological parameters (chlorophyll, carotenoids, total soluble sugar, and phenolic content) of the plants with respect to single culture inoculation, chemical fertilizer, and untreated control. A bacterial consortium having potential to promote plant growth could be used as bioinoculant for horticulture crops growing in hilly regions.

• Klíčová slova
• Agricultural sustainability, Growth parameters, NPK consortium, Physiological parameters, Plant growth promotion,
• MeSH
• Bacteria * genetika   klasifikace   metabolismus   izolace a purifikace   růst a vývoj   MeSH
• draslík metabolismus   MeSH
• dusík metabolismus   MeSH
• fixace dusíku * MeSH
• fosfor * metabolismus   MeSH
• fylogeneze MeSH
• kořeny rostlin mikrobiologie   MeSH
• mikrobiální společenstva * MeSH
• půdní mikrobiologie * MeSH
• rhizosféra MeSH
• RNA ribozomální 16S * genetika   MeSH
• Solanum melongena * mikrobiologie   MeSH
• vývoj rostlin MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• draslík MeSH
• dusík MeSH
• fosfor * MeSH
• RNA ribozomální 16S * MeSH

Real time PCR (quantitative PCR, qPCR) is now a well-established method for the detection, quantification, and typing of different microbial agents in the areas of clinical and veterinary diagnostics and food safety. Although the concept of PCR is relatively simple, there are specific issues in qPCR that developers and users of this technology must bear in mind. These include the use of correct terminology and definitions, understanding of the principle of PCR, difficulties with interpretation and presentation of data, the limitations of qPCR in different areas of microbial diagnostics and parameters important for the description of qPCR performance. It is not our intention in this review to describe every single aspect of qPCR design, optimization, and validation; however, it is our hope that this basic guide will help to orient beginners and users of qPCR in the use of this powerful technique.

• Klíčová slova
• accuracy, limit of detection, limit of quantification, precision, quantitative PCR, trueness,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Current models predict increases in High Arctic temperatures and precipitation that will have profound impacts on the Arctic hydrological cycle, including enhanced glacial melt and thawing of active layer soils. However, it remains uncertain how these changes will impact the structure of downstream resident freshwater microbial communities and ensuing microbially driven freshwater ecosystem services. Using the Lake Hazen watershed (Nunavut, Canada; 82°N, 71°W) as a sentinel system, we related microbial community composition (16S rRNA gene sequencing) to physicochemical parameters (e.g. dissolved oxygen and nutrients) over an annual hydrological cycle in three freshwater compartments within the watershed: (i) glacial rivers; (ii) active layer thaw-fed streams and waterbodies and (iii) Lake Hazen, into which (i) and (ii) drain. Microbial communities throughout these freshwater compartments were strongly interconnected, hydrologically, and often correlated with the presence of melt-sourced chemicals (e.g. dissolved inorganic carbon) as the melt season progressed. Within Lake Hazen itself, water column microbial communities were generally stable over spring and summer, despite fluctuating lake physicochemistry, indicating that these communities and the potential ecosystem services they provide therein may be resilient to environmental change. This work helps to establish a baseline understanding of how microbial communities and the ecosystem services they provide in Arctic watersheds might respond to future climate change.

• Klíčová slova
• Arctic, Lake Hazen, biogeochemistry, freshwaters, glacial rivers, microbial ecology, soil active layer streams, watersheds,
• MeSH
• ekosystém MeSH
• jezera mikrobiologie   MeSH
• klimatické změny MeSH
• mikrobiologie vody * MeSH
• mikrobiota * MeSH
• půda MeSH
• půdní mikrobiologie MeSH
• řeky mikrobiologie   MeSH
• RNA ribozomální 16S MeSH
• roční období MeSH
• sladká voda mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Arktida MeSH
• Nunavut MeSH
• Názvy látek
• půda MeSH
• RNA ribozomální 16S MeSH

It is not well understood how the ecological status and microbial community composition of spruce swamp forests (SSF) relate to those found in bogs and fens. To clarify this, we investigated biogeochemical parameters and microbial community composition in a bog, a fen and two SSF using high throughput barcoded sequencing of the small ribosomal subunit (SSU) variable region V4. The results demonstrated that the microbial community of SSF is positioned between those of bogs and fens, and this was confirmed by in silico predicted metabolic potentials. This corresponds well with the position of SSF on the trophic gradient and reflects distinct responses of microbial communities to environmental variables. Species richness and microbial diversity increased significantly from bog to fen, with SSF in between, reflecting the variation in pH, nutrient availability and peat decomposability. The archaeal community, dominated by hydrogenotrophic methanogens, was more similar in SSF and the bog compared with the fen. The composition of the bacterial community of SSF was intermediate between those of bog and fen. However, the production of CO2 (an indicator of peat decomposability) did not differ between SSF and bog, suggesting the limiting effect of low pH and poor litter quality on the functioning of the bacterial community in SSF. These results help to clarify the transitional position of SSF between bogs and fens and showed the strong effect of environmental conditions on microbial community composition and functioning.

• Klíčová slova
• Archaea, bacteria, bog, fen, microbial diversity, spruce swamp forest,
• MeSH
• Bacteria klasifikace   genetika   metabolismus   MeSH
• biodiverzita MeSH
• Euryarchaeota klasifikace   genetika   metabolismus   MeSH
• lesy * MeSH
• methan biosyntéza   MeSH
• mikrobiální společenstva * MeSH
• mokřady * MeSH
• oxid uhličitý metabolismus   MeSH
• počítačová simulace MeSH
• půda MeSH
• půdní mikrobiologie * MeSH
• smrk MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• methan MeSH
• oxid uhličitý MeSH
• půda MeSH

The effects of lead, zinc, cadmium, arsenic and copper deposits on soil microbial parameters were investigated at a site exposed to contamination for over 200 years. Soil samples were collected in triplicates at 121 sites differing in contamination and soil organic carbon (SOC). Microbial biomass, respiration, dehydrogenase activity and metabolic quotient were determined and correlated with total and extractable metal concentrations in soil. The goal was to analyze complex interactions between toxic metals and microbial parameters by assessing the effect of soil organic carbon in the relationships. The effect of SOC was significant in all interactions and changed the correlations between microbial parameters and metal fractions from negative to positive. In some cases, the effect of SOC was combined with that of clay and soil pH. In the final analysis, dehydrogenase activity was negatively correlated to total metal concentrations and acetic acid extractable metals, respiration and metabolic quotient were to ammonium nitrate extractable metals. Dehydrogenase activity was the most sensitive microbial parameter correlating most frequently with contamination. Total and extractable zinc was most often correlated with microbial parameters. The large data set enabled robust explanation of discrepancies in organic matter functioning occurring frequently in analyzing of contaminated soil processes.

• Klíčová slova
• Clay, Dehydrogenase activity, Metals, Respiration, Soil organic C, pH,
• MeSH
• chemické modely MeSH
• kovy analýza   chemie   MeSH
• látky znečišťující půdu analýza   chemie   MeSH
• monitorování životního prostředí * MeSH
• půda chemie   MeSH
• uhlík chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kovy MeSH
• látky znečišťující půdu MeSH
• půda MeSH
• uhlík MeSH

Microbial biostalactites and streamers commonly grow at iron seepages in abandoned mines worldwide. This study addresses the diversity and composition of these simple prokaryotic communities, which thrive in pH ranges from 2.4 to 6.6 across six different mines. Our analysis of 85 communities reveals that a pH of approximately 3.2 is a critical threshold where alpha and beta diversity change discretely. Below this pH, the average number of ASVs per sample is 2.91 times lower than above this boundary. Autotrophs, heterotrophs, and symbionts of eukaryotes originate from nearly non-overlapping species pools in the two habitat types that differ only in pH. Communities below pH 3.2 further divide into two distinct groups, differing in diversity, taxonomic, and functional composition. Both types of communities coexist within the same stalactites, likely corresponding to zones where the capillary structure of the stalactite is either perfused or clogged. These findings indicate that microbial community structure can be significantly influenced by the intricate spatial organization of the ecosystem, rather than solely by measurable environmental parameters.

• MeSH
• Archaea metabolismus   klasifikace   genetika   MeSH
• Bacteria * klasifikace   metabolismus   genetika   MeSH
• biodiverzita MeSH
• ekosystém MeSH
• fylogeneze MeSH
• hornictví MeSH
• koncentrace vodíkových iontů MeSH
• mikrobiota MeSH
• oxidace-redukce * MeSH
• železo * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• železo * MeSH

Northern peatlands typically develop through succession from fens dominated by the moss family Amblystegiaceae to bogs dominated by the moss genus Sphagnum. How the different plants and abiotic environmental conditions provided in Amblystegiaceae and Sphagnum peat shape the respective moss associated microbial communities is unknown. Through a large-scale molecular and biogeochemical study spanning Arctic, sub-Arctic and temperate regions we assessed how the endo- and epiphytic microbial communities of natural northern peatland mosses relate to peatland type (Sphagnum and Amblystegiaceae), location, moss taxa and abiotic environmental variables. Microbial diversity and community structure were distinctly different between Amblystegiaceae and Sphagnum peatlands, and within each of these two peatland types moss taxon explained the largest part of microbial community variation. Sphagnum and Amblystegiaceae shared few (< 1% of all operational taxonomic units (OTUs)) but strikingly abundant (up to 65% of relative abundance) OTUs. This core community overlapped by one third with the Sphagnum-specific core-community. Thus, the most abundant microorganisms in Sphagnum that are also found in all the Sphagnum plants studied, are the same OTUs as those few shared with Amblystegiaceae. Finally, we could confirm that these highly abundant OTUs were endophytes in Sphagnum, but epiphytes on Amblystegiaceae. We conclude that moss taxa and abiotic environmental variables associate with particular microbial communities. While moss taxon was the most influential parameter, hydrology, pH and temperature also had significant effects on the microbial communities. A small though highly abundant core community is shared between Sphagnum and Amblystegiaceae.

• MeSH
• biodiverzita * MeSH
• mechy mikrobiologie   MeSH
• mikrobiota fyziologie   MeSH
• mokřady * MeSH
• rašeliníky mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Arktida MeSH