active soil layer
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Disease-suppressive soils encompass specific plant-pathogen-microbial interactions and represent a rare example of an agroecosystem where soil conditions and microbiome together prevent the pathogen from causing disease. Such soils have the potential to serve as a model for characterizing soil pathogen-related aspects of soil health, but the mechanisms driving the establishment of suppressive soils vary and are often poorly characterized. Yet, they can serve as a resource for identifying markers for beneficial activities of soil microorganisms concerning pathogen prevention. Many recent studies have focused on the nature of disease-suppressive soils, but it has remained difficult to predict where and when they will occur. This review outlines current knowledge on the distribution of these soils, soil manipulations leading to pathogen suppression, and markers including bacterial and fungal diversity, enzymes, and secondary metabolites. The importance to consider soil legacy in research on the principles that define suppressive soils is also highlighted. The goal is to extend the context in which we understand, study, and use disease-suppressive soils by evaluating the relationships in which they occur and function. Finally, we suggest that disease-suppressive soils are critical not only for the development of indicators of soil health, but also for the exploration of general ecological principles about the surrounding landscape, effects of deeper layers of the soil profile, little studied soil organisms, and their interactions for future use in modern agriculture.
We present a biological profile of 16 Aspergillus niger environmental isolates from different types of soils and solid substrates across a pH range, from an ultra-acidic (<3.5) to a very strongly alkaline (>9.0) environment. The soils and solid substrates also differ in varying degrees of anthropic pollution, which in most cases is caused by several centuries of mining activity at old mining sites, sludge beds, ore deposits, stream sediments, and coal dust. The values of toxic elements (As, Sb, Zn, Cu, Pb) very often exceed the limit values. The isolates possess different macro- and micromorphological features. All the identifications of Aspergillus niger isolates were confirmed by molecular PCR analysis and their similarity was expressed by RAMP analysis. The biochemical profile of isolates based on FF-MicroPlate tests from the Biolog system showed identical biochemical reactions in 50 tests, while in 46 tests the utilisation reactions differed. The highest similarity of strains isolated from substrates with the same pH, as well as the most suitable biochemical tests for analysis of the phenotypic similarity of isolated strains, were confirmed when evaluating the biochemical profile using multicriterial analysis in the Canoco program. The isolates were screened for mycotoxin production by thin-layer chromatography (TLC), as well. Two of them were able to synthesise ochratoxin A, while none produced fumonisins under experimental conditions. Presence of toxic compounds in contaminated sites may affect environmental microscopic fungi and cause the genome alteration, which may result in changes of their physiology, including the production of different (secondary) metabolites, such as mycotoxins.
- Publikační typ
- časopisecké články MeSH
Streptomyces have been reported as a remarkable source for bioactive secondary metabolites with complex structural and functional diversity. In this study, 35 isolates of genus Streptomyces were purified from rhizospheric and marine soils collected from previously unexplored habitats and screened for antimicrobial activities. One of these isolates, G1, when tested in vitro, was found highly active against wide range of microbes including Gram-positive, Gram-negative bacteria, and different fungal pathogens. It was identified as mesophilic, alkaliphilic, and moderately halotolerant as it showed optimum growth at temperature 30 °C, pH 8.0 in casein-starch-peptone-yeast extract-malt extract medium supplemented with 5% NaCl. Sequence analysis of the 16S rRNA gene indicated 100% identity of this isolate to Streptomyces fimbriatus. Moreover, maximum antimicrobial activity was achieved in starch nitrate medium supplemented with 1% glycerol as carbon and 0.03% soy meal as nitrogen source. The antimicrobial compounds produced by this isolate were extracted in methanol. Bioassay-guided fractionation through thin layer chromatography of methanolic extract resulted in the separation of a most active fraction with an Rf value of 0.46. This active fraction was characterized by FTIR and LCMS analysis and found similar to streptothricin D like antibiotic with m/z 758.42.
Substantial amounts of topsoil organic matter (OM) in Arctic Cryosols have been translocated by the process of cryoturbation into deeper soil horizons (cryoOM), reducing its decomposition. Recent Arctic warming deepens the Cryosols´ active layer, making more topsoil and cryoOM carbon accessible for microbial transformation. To quantify bacteria, archaea and selected microbial groups (methanogens - mcrA gene and diazotrophs - nifH gene) and to investigate bacterial and archaeal diversity, we collected 83 soil samples from four different soil horizons of three distinct tundra types located in Qikiqtaruk (Hershel Island, Western Canada). In general, the abundance of bacteria and diazotrophs decreased from topsoil to permafrost, but not for cryoOM. No such difference was observed for archaea and methanogens. CryoOM was enriched with oligotrophic (slow-growing microorganism) taxa capable of recalcitrant OM degradation. We found distinct microbial patterns in each tundra type: topsoil from wet-polygonal tundra had the lowest abundance of bacteria and diazotrophs, but the highest abundance of methanogens. Wet-polygonal tundra, therefore, represented a hotspot for methanogenesis. Oligotrophic and copiotrophic (fast-growing microorganism) genera of methanogens and diazotrophs were distinctly distributed in topsoil and cryoOM, resulting in different rates of nitrogen flux into these horizons affecting OM vulnerability and potential CO2 and CH4 release.
- MeSH
- mikrobiota * MeSH
- ostrovy MeSH
- permafrost * MeSH
- půda MeSH
- půdní mikrobiologie MeSH
- tundra MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Arktida MeSH
- Kanada MeSH
- ostrovy MeSH
Functional plasmonic fiber for detection and on-line monitoring of organophosphorus pesticides in water or model soil samples is described. The appearance of the plasmon absorption band was realized through the deposition of a thin gold layer on the naked core of multimode optical fiber. The metalorganic frameworks (MOF-5) layer was deposited on the gold surface for the introduction of a high affinity towards the target pesticides. The MOF-5 layer affords the extraction of pesticides and their concentration primarily in the "plasmon evanescent wave" space, allowing the detection by the shift of plasmon absorption band. The growth of MOF-5 layer was confirmed using the Raman, XPS and XRD measurements. The entrapping of pesticides was checked using the Raman spectroscopy and ellipsometry, which also indicate the corresponding changes of MOF-5 refractive index. The series of further experiments demonstrate the applicability of proposed fiber sensor for detection of pesticides in soil without the false signals from surrounding media. The main advantages of proposed sensor can be attributed to simplicity, high sensitivity, low cost and the absence of organic solvents for the probe treatment.
- Publikační typ
- časopisecké články MeSH
World mushroom production in 2018 was approximately 8.99 million tonnes. The most commonly cultivated species in the Czech Republic are Agaricus spp., which are sold fresh or canned. In 2017, 2018 mushroom production in the Czech Republic was approximately 540 tonnes. Vermicomposting is an easy and less ecologically harmful way to process the spent mushroom substrate. Earthworms, which are referred to as the engine of the process of vermicomposting, and microorganisms, help convert organic waste into fertilizer. This study is concerned with laboratory vermicomposting in a system of continuous feeding of earthworms Eisenia andrei. It compares the differences between variants with and without earthworms. The dry matter percentage was approximately 20% or more in both variants. The variant with earthworms showed a significant decrease in electrical conductivity. The C/N ratio was very low in both variants. The highest total P was recorded in the variant with earthworms, but the highest values of K and Mg were found in the control. Both variants recorded higher content of bacteria than fungi. All values of microorganism contents were higher in the vermicomposter without earthworms, but the bacterial/fungal ratio was higher in the variant with earthworms. The highest content in both variants shows the bacteria especially G-bacteria, on the other side, the lowest content shows the actinobacteria. The highest activity of β-D-glucosidase and acid phosphatase was measured in the vermicomposter with earthworms, but the activity of other enzymes was higher in the control. In both vermicomposters laccase activity was below the detection limit. The method of classical vermicomposting can be used for processing the spent mushroom substrate. However, in terms of higher content of total and available nutrients, there seems to be a better method of processing the substrate without earthworms.
- MeSH
- Agaricus * MeSH
- Bacteria MeSH
- houby MeSH
- Oligochaeta * MeSH
- půda MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Malting sludge is waste that could be used as a good soil conditioner after proper treatment. In the current study, the feasibility of vermicomposting malting sludge and its mixtures with straw pellets on the basis of physico-chemical and biological properties was verified. A vermicomposting system with continuous feeding of earthworms Eisenia andrei was used. The greatest number and biomass of earthworms was found in the variant with 25% malt house sludge + 75% straw pellets (on average of all layers: 320 earthworms/kg and 35 g/kg, respectively), followed by a variant with 50% malt house sludge + 50% straw pellets (on average of all layers: 47 earthworms/kg and 13 g/kg, respectively), indicating that a minimum of 50% (vol.) straw pellets is necessary for successful vermicomposting of malting sludge. Most earthworms lived in the youngest upper layer (42% and 52% of total number and earthworm biomass, respectively). On the contrary, the oldest bottom layers (final vermicomposts) after 180 days of vermicomposting were characterized by maturity, indicating lesser contents of microorganisms and enzyme activity. These vermicomposts had favorable agrochemical properties (pH = 7.8, EC = 1.2 mS cm-1, C/N = 11, Ptot = 1.23%, Ktot = 2.55%, Mgtot = 0.42%). The proportion of the available contents in the total contents were 10%, 59%, and 19% for P, K, and Mg, respectively.
- MeSH
- biomasa MeSH
- odpadní vody * MeSH
- Oligochaeta * MeSH
- půda MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The possibility of Miscanthus×giganteus cultivation as an energy crop on the different types of mining rocks was studied. It was revealed that a loess-like loam and red-brown clay with the added black soil were the most suitable for plant growing. The yield of dry above-ground biomass ranged from 4.3 to 6.8 t DM ha-1 after the first year of cultivation and from 8.9 to 9.7 t DM ha-1 after the second year while using these substrates. The application of amendments stimulated the growth and development of plants and increased productivity from 50 to 140%. M.×giganteus showed sufficient tolerance and good enough growth on the geochemically active dark-gray schist clay with yield from 2 to 3 t DM ha-1 after the first year of cultivation already. For plants grown on the different strata of dark-gray schist clay, the thermal decomposition of the biomass took place in four stages in the temperature range from 30 to 640 °C. The samples grown on stratum 0-20 cm showed the highest reactivity with a peak 30.6%/min at 290 °C. There were differences in the concentrations of determined heavy metals: iron, zinc, copper, and lead in the plant tissues depending on the layer depth of dark-gray schist clay from 0 to 20 cm to 40-60 cm. The relatively limited content of heavy metals in the above-ground biomass was due to the preferential accumulation in the roots.
- MeSH
- biologická adaptace * MeSH
- biomasa MeSH
- hornictví * MeSH
- kořeny rostlin chemie růst a vývoj MeSH
- látky znečišťující půdu analýza MeSH
- lipnicovité chemie růst a vývoj MeSH
- půda chemie MeSH
- těžké kovy analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Ukrajina MeSH
Self-propelled microrobots are seen as the next step of micro- and nanotechnology. The biomedical and environmental applications of these robots in the real world need their motion in the confined environments, such as in veins or spaces between the grains of soil. Here, self-propelled trilayer microrobots have been prepared using electrodeposition techniques, coupling unique properties of green bismuth (Bi) with a layered crystal structure, magnetic nickel (Ni), and a catalytic platinum (Pt) layer. These Bi-based microrobots are investigated as active self-propelled platforms that can load, transfer, and release both doxorubicin (DOX), as a widely used anticancer drug, and arsenic (As) and chromium (Cr), as hazardous heavy metals. The significantly high loading capability for such variable cargoes is due to the high surface area provided by the rhombohedral layered crystal structure of bismuth, as well as the defects introduced through the oxide layer formed on the surface of bismuth. The drug release is based on an ultrafast electroreductive mechanism in which the electron injection into microrobots and consequently into the loaded objects causes an electrostatic repulsion between them and thus an ultrafast release of the loaded cargos. Remarkably, we have presented magnetic control of the Bi-based microrobots inside a microfluidic system equipped with an electrochemical setup as a proof-of-concept to demonstrate (i) heavy metals/DOX loading, (ii) a targeted transport system, (iii) the on-demand release mechanism, and (iv) the recovery of the robots for further usage.
- MeSH
- bismut * chemie toxicita MeSH
- chrom chemie toxicita MeSH
- doxorubicin * chemie MeSH
- lidé MeSH
- nádory * farmakoterapie patologie MeSH
- nanotechnologie trendy MeSH
- platina chemie toxicita MeSH
- protinádorové látky chemie terapeutické užití MeSH
- těžké kovy chemie toxicita MeSH
- uvolňování léčiv MeSH
- uzavřené prostory MeSH
- Check Tag
- lidé 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.
- 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
