Functional Groups Of Microorganisms Research Articles

Abundance and Diversity of Microorganisms in Soils and Associated Substrates (Leaf Litter and “Suspended Soil”) in Some Nature Reserves of Vietnam

A comprehensive study has been carried out, and a quantitative and qualitative characteristic of the soil prokaryotic community of zonal Ferralsol and intrazonal Fluvisol of Vietnam, as well as associated leaf litter and “suspended” soil from epiphytic ferns, has been given. The greatest number of bacteria, determined by the direct luminescence method, was associated with samples of Fluvisol, while the lengths of fungal and actinomycete mycelium were the largest in mountainous ferralitic soils. Bacteria of the genus Streptomyces, included in the saprotrophic bacterial complex of the studied substrates, make a significant contribution to the destruction of plant material. The bacteria of the phyla Firmicutes (80%) and Proteobacteria (15%) predominated in the prokaryotic community of the zonal red-yellow humus-ferrallitic soil, while the phyla Proteobacteria (51%) and Actinobacteria (38%) dominated in the sample of the “suspended” soil. The phyla Chloroflexi, Acidobacteria, Bacteroidetes, and Cyanobacteria were significantly less represented. With significant differences at the level of genera in the studied substrates, similar functional groups of microorganisms were identified: xenobiotic decomposers, nitrogen cycle bacteria, extremophiles, as well as bacteria that inhibit the growth of micromycetes. The metabolically active part of the prokaryotic community, represented by the phyla Proteobacteria, Actinobacteria, and Acidobacteria, was the highest in the “suspended” soil and the least active in the litter and horizon A of Ferralsol, which correlated with the high abundance of these phyla and the significant taxonomic diversity of bacteria in this locus. Functional genes (nifH and alkB) were detected in all studied substrates. The number of copies of functional genes was the highest in the “suspended” soil sample, which makes this locus promising for isolating strains with high biotechnological potential.

Effect of zinc and iron oxide nanoparticles on plant physiology, seed quality and microbial community structure in a rice-soil-microbial ecosystem

In this study, we assessed the impact of zinc oxide (ZnO) and iron oxide (FeO) (<36 nm) nanoparticles (NPs) as well as their sulphate salt (bulk) counterpart (0, 25, 100 mg/kg) on rice growth and seed quality as well as the microbial community in the rhizosphere environment of rice. During the rice growing season 2021–22, all experiments were conducted in a greenhouse (temperature: day 30 °C; night 20 °C; relative humidity: 70%; light period: 16 h/8 h, day/night) in rice field soil. Results showed that low concentrations of FeO and ZnO NPs (25 mg/kg) promoted rice growth (height (29%, 16%), pigment content (2%, 3%)) and grain quality parameters such as grains per spike (8%, 9%), dry weight of grains (12%, 14%) respectively. As compared to the control group, the Zn (2%) and Fe (5%) accumulations at their respective low concentrations of NP treatments showed stimulation. Interestingly, our results showed that at low concentration of both the NPs the soil microbes had more diversity and richness than those in the bulk treated and control soil group. Although a number of phyla were affected by the presence of NPs, the strongest effects were observed for change in the abundance of the three phyla for Proteobacteria, Actinobacteria, and Planctomycetes. The rhizosphere environment was notably enriched with potential streptomycin producers, carbon and nitrogen fixers, and lignin degraders with regard to functional groups of microorganisms. However, microbial communities mainly responsible for chitin degradation, ammonia oxidation, and nitrite reduction were found to be decreased. The results from this study highlight significant changes in several plant-based endpoints, as well as the rhizosphere soil microorganisms. It further adds information to our understanding of the nanoscale-specific impacts of important micronutrient oxides on both rice and its associated soil microbiome.

The Effect of Stand Structure on Soil Physico-Chemical and Biological Properties in a Primary Beech Forest

The study investigates the links and interactions between soil properties, soil microorganisms and the structure of a primary beech forest. The study was performed in the reserve Havešová (Bukovské vrchy Mts., Slovakia). On 40 sampling plots, soil samples from the O-horizon and from the first 10 cm of the organo-mineral horizons were taken to analyze the physico-chemical and biological properties. Moreover, stand structural characteristics (volume of trees, additive stand density index, coefficient of homogeneity, tree influence potential, development stage indices, etc.) were measured and calculated. In general, we did not observe any strong effects of forest structure on the topsoil characteristics. The effect of stand structure was more reflected in the physico-chemical properties than in the biological attributes. We found that the P and K content in the forest floor increased at plots with a higher volume or density of trees per plot. Moreover, a positive correlation was found also between the K content and tree influence potential. The development stages expressed by the indexes based on the diameter structure were reflected especially by the soil reaction in the A-horizon. Within functional groups of microorganisms based on the Biolog assay, significant differences were found, especially in the utilization of D-cellobiose, which positively correlated with the presence of the optimum stage index. The effect of soil physico-chemical properties on biological indicators was more pronounced than the effect of stand structure.

Bacterial Cadmium-Immobilization Activity Measured by Isothermal Microcalorimetry in Cacao-Growing Soils From Colombia

In cacao farms, the presence of cadmium (Cd) is a major issue for commercialization, particularly for countries such as Colombia. Cadmium-tolerant bacteria (CdtB) are an important functional group of microorganisms with a potential for bioremediation strategies. Cd immobilization activity by CdtB can be accurately measured by isothermal microcalorimetry (IMC). In this study, the metabolic capacity of an entire CdtB community in cacao farm soils from three cacao-producing districts of Colombia, with and without the addition of Cd was measured using IMC. The differences between the observed peaks in metabolic activity related to Cd immobilization were analysed to determine whether activation of CdtB populations occurred when Cd content was increased. The thermograms from Santander soil samples have a major metabolic activity of the CdtB community compared to peaks of maximal heat-flow in the samples from Antioquia and Arauca. IMC showed differences in Cd immobilization ratios of the soil samples of 0.11–0.30 mg kg−1 h−1 at 25°C over 12 days of thermal monitoring. Furthermore, the amplicons of cadA and smt genes from the soil samples allow elucidation of possible metabolic mechanisms used by CdtB soil populations. The gene amplification confirmed the existence of CdtB populations related to both bioweathering and biochelating metabolic capacities. Scanning electron microscope (SEM) images supported the existence of otavite biologically induced by CdtB naturally. A Pearson correlation analysis was made between kinetical growth parameters and thermodynamic data. Besides, a PCA was performed between CdtB cadA gene copies, soil pH and SOM indicating the effect of CdtB in Cd translocation. Thus, it is concluded that the combination of Cd immobilization ratios obtained using isothermal microcalorimetry, the molecular basis of metabolic immobilization, and SEM imagery could act as a useful toolkit to identify CdtB populations for bioremediation strategies in contaminated cacao farms. The research importance of this study is the use of combined tools for quantitative IMC measurements to identify and assess Cd metabolic capacities of CdtB populations in soil, in situ, as a new proxy for CdtB assessment in cacao-growing soils.

Digging deeper: microbial communities in subsoil are strongly promoted by trees in temperate agroforestry systems

AimsTemperate alley-cropping agroforestry systems maintain agricultural production while offering several environmental benefits. Central benefits of agroforestry systems such as the ‘safety-net’-role of the trees for leached nutrients are mainly due to processes occurring below the soil surface: the subsoil. Microorganisms in the subsoil may play a key role in the ‘safety-net’-function as they can improve the capturing and uptake of nutrients by the trees. Systematic investigations of microbial communities in temperate agroforestry systems, however, are restricted to topsoil.MethodsWe quantified bacteria, fungi, and functional groups of microorganisms in the topsoil and subsoil of two alley-cropping systems using real-time PCR. Topsoil and subsoil samples were collected in the tree rows and at multiple distances from the trees within the crop rows of the agroforestry systems as well as at an adjacent monoculture cropland.ResultsMicrobial population size decreased with soil depth likely due to limited resource availability in subsoil. Tree rows in agroforestry systems not only promote soil microbial populations in both the topsoil and subsoil but the promotion also extends gradually into the crop rows of the systems. The promotion of microorganisms through trees is stronger in subsoil than topsoil, pointing at more intense resource scarcity in the subsoil than topsoil.ConclusionsWe propose that tree root-derived resources and root litter, which are scarce in agricultural subsoils, triggered the strong positive response of the subsoil community to the trees. Finally, we provide initial evidence that subsoil microorganisms contribute to the ‘safety-net’-role of the trees in agroforestry systems.

Coupled CFD-DEM modeling to predict how EPS affects bacterial biofilm deformation, recovery and detachment under flow conditions.

The deformation and detachment of bacterial biofilm are related to the structural and mechanical properties of the biofilm itself. Extracellular polymeric substances (EPS) play an important role on keeping the mechanical stability of biofilms. The understanding of biofilm mechanics and detachment can help to reveal biofilm survival mechanisms under fluid shear and provide insight about what flows might be needed to remove biofilm in a cleaning cycle or for a ship to remove biofilms. However, how the EPS may affect biofilm mechanics and its deformation in flow conditions remains elusive. To address this, a coupled computational fluid dynamic– discrete element method (CFD‐DEM) model was developed. The mechanisms of biofilm detachment, such as erosion and sloughing have been revealed by imposing hydrodynamic fluid flow at different velocities and loading rates. The model, which also allows adjustment of the proportion of different functional groups of microorganisms in the biofilm, enables the study of the contribution of EPS toward biofilm resistance to fluid shear stress. Furthermore, the stress–strain curves during biofilm deformation have been captured by loading and unloading fluid shear stress to study the viscoelastic properties of the biofilm. Our predicted emergent viscoelastic properties of biofilms were consistent with relevant experimental measurements.

Phage Genome Diversity in a Biogas-Producing Microbiome Analyzed by Illumina and Nanopore GridION Sequencing.

The microbial biogas network is complex and intertwined, and therefore relatively stable in its overall functionality. However, if key functional groups of microorganisms are affected by biotic or abiotic factors, the entire efficacy may be impaired. Bacteriophages are hypothesized to alter the steering process of the microbial network. In this study, an enriched fraction of virus-like particles was extracted from a mesophilic biogas reactor and sequenced on the Illumina MiSeq and Nanopore GridION sequencing platforms. Metagenome data analysis resulted in identifying 375 metagenome-assembled viral genomes (MAVGs). Two-thirds of the classified sequences were only assigned to the superkingdom Viruses and the remaining third to the family Siphoviridae, followed by Myoviridae, Podoviridae, Tectiviridae, and Inoviridae. The metavirome showed a close relationship to the phage genomes that infect members of the classes Clostridia and Bacilli. Using publicly available biogas metagenomic data, a fragment recruitment approach showed the widespread distribution of the MAVGs studied in other biogas microbiomes. In particular, phage sequences from mesophilic microbiomes were highly similar to the phage sequences of this study. Accordingly, the virus particle enrichment approach and metavirome sequencing provided additional genome sequence information for novel virome members, thus expanding the current knowledge of viral genetic diversity in biogas reactors.

Community homeostasis of coastal microbial mats from the Camargue during winter (cold) and summer (hot) seasons

AbstractMicrobial mats are complex layered biofilms under the effect of continuous daily and seasonal fluctuations in abiotic factors such as nutrients, pH, light, temperature, and salinity. In this study, community variability of microbial mats from the Camargue wetlands (Rhone Delta, southern France) was determined in winter and summer over 2 years, analyzing thin vertical layers at three different depths (0–2, 2–4, and 4–6 mm). Amplicons of the V1–V2 region of the 16S rRNA gene were sequenced to assess changes in the bacterial diversity of the mats. Functionality was inferred according to PICRUSt bioinformatics analysis. The microbial composition of the three layers included more than 30 phyla of bacteria, the major phyla being Proteobacteria, Bacteroidetes, Cyanobacteria, and Spirochaetes. The microbial composition of the layers differed significantly, especially between layer 1 (0–2 mm) and the other two, regardless of the season. Cyanobacteria and Rhodobacteraceae (Alphaproteobacteria) were more abundant in layer 1. Chromatiaceae (Gammaproteobacteria) and Deltaproteobacteria were detected in layers 2 (2–4 mm) and 3 (4–6 mm). Flavobacteriaceae was the predominant family of the phylum Bacteroidetes, being especially abundant in layer 3. Spirochaetes were distributed in all three layers, but above all in layer 2. Pathways related to energy and carbohydrate metabolism indicated that the community was more active in summer than in winter. Carbon fixation in the mats was predominantly through the Wood–Ljungdahl pathway. Heterotrophic diazotrophs appeared to be responsible for a substantial part of nitrogen input, even more than phototrophic microorganisms. Layers 1 and 2 represented a stressed environment, measured by relative abundances of KEGG Orthologs associated with oxidation, starvation, and osmotic and xenobiotic stress, and suffered unbalanced growth in which there is no increase in cell numbers, but it allows the accumulation of polymers, such as polyhydroxybutyrate. The Camargue mats showed a community homeostasis, its populations adapting to fluctuating conditions while maintaining the characteristic structure of vertically stratified functional groups of microorganisms.

Изучение влияния минерала шунгита на микробиоту кишечника кур-несушек

The aim of the study is to study the effect of the mineral shungite on the intestinal microbiota of laying hens for the needs of poultry farming. To solve this problem in the conditions of the vivarium of the International Laboratory of Molecular Genetics and Poultry Genomics, MVA by K. I. Skryabin, an experiment was set up on laying hens (Hisex Brown cross). The diet of laying hens of the experimental group differed from the control group by introducing a feed additive from shungite at a dosage of 1 kg per ton of feed. In accordance with the goal, the objectives of the study included the calculation of the index of bioconsolidation of microorganisms in microbial biosystems and the index of the composition of chemical elements in shungite and mixed fodder, the construction of a fractal portrait of the corresponding series of numbers, reflecting the series of numbers of microorganisms or the content of chemical elements in shungite. Thus, it was shown that shungite, with its special ratio of chemical elemental composition, favorably affects the self-organization of microbial-organismal biosystems of the intestines of laying hens and the intestinal microbiota of laying hens in general. The ratio of chemical elements in shungite imposes a certain matrix on the ratio of various functional groups of microorganisms in the intestines of birds, which ensures the best joint activity of microorganisms in converting organic substrates into nutrients.

Characteristics of Low-Oxygen Oxidation Ditch with Improved Nitrogen Removal

This article presents a study on the operational stability of laboratory oxidation ditches, designated for synthetic and real wastewater and operable at low concentrations of dissolved oxygen. The project encompassed the stability monitoring of activated sludge depending on sedimentation characteristics and hydrobiological indicator microorganisms, determining (1) the size of sludge floccules and (2) the main functional groups of microorganisms identified in the course of the PCR analysis and reaction rates, plotted using the Michaelis–Menten enzymatic kinetics for the mixed culture biomass. The most stable system involves a bioreactor featuring dissolved oxygen gradients that range from 1.9 to 0.15 mg/L s, a specific organic load of 0.21 gBOD/g/d and a hydraulic retention time of 12 h. A built-in settling tank allows the consideration of the potential generation of large floccules of activated sludge in oxidation ditches (at least 300 μm) that increase the efficiency of simultaneous nitrification and denitrification. Thus, the obtained reaction rates can be used in calculations and simulations of the operation of oxidation ditches at low concentrations of dissolved oxygen.

Organic Matter Degradation in Energy-Limited Subsurface Environments—A Bioenergetics-Informed Modeling Approach

Microbial degradation of organic matter is a key driver of subsurface biogeochemistry. Here, we present a bioenergetics-informed kinetic model for the anaerobic degradation of macromolecular organic matter that accounts for extracellular hydrolysis, fermentation, and respiration. The catabolic energy generated by fermentation and respiration is allocated to biomass growth, production of extracellular hydrolytic enzymes, and cellular maintenance. Microbial cells are assumed to exist in active or dormant states with marked differences in maintenance energy requirements. Dormant cells are further assumed to fulfill their maintenance energy requirements by utilizing their own biomass instead of relying on external substrates. When the catabolic Gibbs energy production for a given functional group of microorganisms exceeds the total maintenance energy requirement of the active cells, biomass growth, re-activation of dormant cells, and production of extracellular hydrolytic enzymes are possible. The latter, in turn, allows the microbial community to access more of the available external organic substrates. In the opposite case, active cells decay or become dormant. We apply the model to simulate the anaerobic degradation of cellulose by a hypothetical microbial community consisting of cellulolytic fermenting bacteria and sulfate-reducing bacteria, under conditions representative of those encountered in water-saturated subsurface environments.

INFLUENCE OF DIFFERENT SYSTEMS OF CROP FARMING ON ECOLOGICAL AND TROPHIC GROUPINGS OF MICROORGANISMS OF TYPICAL CHORNOZEM IN THE CONDITIONS OF THE LEFT-BANK FOREST STEPPE OF UKRAINE

Objective. To establish the influence of different crop farming systems on the parameters of the number of representatives of ecological and trophic groups of microorganisms in typical chernozem. Methods. Comparative-profile-genetic, microbiological, statistical. Results. The upper 0–10- centimetre layer of soil (the number of microorganisms decreases with depth and the predominance of microbiological activity in the 10–20-centimetre layer is possible only in dry periods) is characterised by the highest microbiological activity. The microbiocenosis undergoes the greatest transformations in the conditions of intensive system of crop farming upon mixing and turn of a layer. This is expressed in a significant decrease in microbiological activity in the 0–10-centimetre layer and vice versa — an increase in the layers of 10–20 and 20–30 cm. Agrogenic soils have higher parameters of total microbiological activity compared to the fallow area. The most positive influence on biogenesity was reported in the variants of the organic system of crop farming, especially with the use of green manures. The data on the directions of development of soil biological processes of the studied variants by the analysis of oligotrophic coefficients, mineralization-immobilization and mobilization of nitrogen stock are provided. Mathematical analysis of the data showed a significant influence of the depth of sampling on the number of all studied microorganisms, while the crop farming system significantly affected the number of microscopic fungi, actinomycetes and amylolytic microbiota. Conclusion. Agrogenic use of chernozems reduces the number of microscopic fungi. In the variants of organic crop farming, a significant increase in the number of actinomycetes and amylolytic microbiota was reported. Under the intensive system of crop farming, there is a decreased number of representatives of all studied ecological and trophic groups of microorganisms. And vice verse, variants of the organic crop farming system, especially under the use of green manure, have a higher number of most functional groups of microorganisms. Cultivated soils are characterized by a higher coefficient of mineralization and immobilization compared to fallow.

Аналіз ризосферного мікробіому цукрової кукурудзи за впливу хімічних і біологічних протруйників

У статті представлено результати впливу хімічних і біологічних протруйників на кількісний склад мікробіому ризосфери цукрової кукурудзи протягом її вегетації. Показано, що за використання хімічних препаратів у ризосфері рослин на порядок знижується кількість амоніфікаторів та мікроскопічних грибів у першій половині вегетаційного періоду культури. Вплив ксенобіотиків на вміст актиноміцетів, олігонітрофілів та педоторофів є менш токсичним. У порівнянні з контрольним варіантом вміст даних мікроорганізмів знижувався на 50-75 %, при цьому змін зазнає не лише кількісний, а й якісний склад ризосферної мікрофлори. У той же час досліджувані пестициди не впливали на вміст актиноміцетів і оліготрофів. По мірі розвитку рослин негативний вплив хімічних протруйників на мікрофлору ґрунту поступово нівелювався. Відбувалося відновлення складу ризосферної мікробіоти у кожній умовній функціональній групі мікроорганізмів і до завершення вегетації кукурудзи мікробний ценоз повертався до свого первинного кількісного і якісного складу. Застосування мікробіологічних засобів захисту не призводило до змін чисельності чи дисбалансу у складі ґрунтової мікробіоти. Її кількісний та якісний склад відповідав контрольному варіанту.

Soil Quality Indicators Associated With The Application Of Mycorrhizal Fungi In Coffee Plantations

Introduction: This article is the result of the research work “Evaluation of the quality of the soil associated with the use of mycorrhizae in coffee plantations in the Municipality of Sasaima, Cundinamarca” carried out duringthe years 2018 and 2019 at the Universidad Libre.&#x0D; Problem: Several investigations report the use of mycorrhizal fungi in plant development, however, there are few studies regarding the relationship between mycorrhizae and soil quality indicators.&#x0D; Methodology: Four plots were evaluated, applying: 1) Control; 2) Local native mycorrhizae isolated by the authors; 3) Commercial liquid mycorrhizae; and 4) Commercial solid mycorrhizae. The samples of the rhizosphericsoils were taken and bimonthly monitoring was applied until 5 collection cycles were obtained. The physicochemical parameters, abundance of functional groups of microorganisms, and enzymatic activities ofthe soil were determined and analyzed by means of univariate and multivariate statistical analysis.&#x0D; Conclusion: The research hypothesis was validated since the mycorrhizae inoculation significantly increased the values of the soil quality indicators, namely organic carbon (14%), moisture (19%), phosphorus (30%), abundanceof nitrogen-fixing bacteria (5.5%), phosphate-solubilizing bacteria (7.8%), cellulolytic bacteria (9.3%), and phosphate-solubilizing fungi (2.6%). In addition, the local native mycorrhizae that were isolated by theauthors showed greater benefits than those of the commercial mycorrhizae.&#x0D; Originality: This research reveals the impact of mycorrhizae on the soil quality indicators over time during thefirst year of application, especially on the microbial and enzymatic parameters.&#x0D; Limitations: Several authors have investigated the importance of the mycorrhizae on the physicochemical parameters of the plant, and not on the microbial and enzymatic parameters of the soil.

Uranium speciation and distribution in Shewanella putrefaciens and anaerobic granular sludge in the uranium immobilization process

The uranium (U) in Shewanella putrefaciens (S. putrefaciens) and anaerobic granular sludge (AnGS) were fractionated, and the contents and forms of U in each fraction were investigated. The functional groups of microorganisms for U binding and the deposition of U in microbial aggregates were also analyzed. Four main approaches were found involved in U immobilization, including biosorption/complexation by microbial cells and their extracellular polymeric substances (EPS), non-reductive biomineralization, bioreduction and intracellular accumulation. Results show that non-reductive biomineralization was found to be dominated in the U(VI) immobilization process. Besides, the contribution of EPS to U removal could not be ignored.

Effect of management (ecological and conventional) on functional groups of soil microorganisms in coffee agroecosystems with different resilience to climate variability, Colombia

The effect of management (ecological and conventional) on functional groups of microorganisms of soil in agroecosystems with different resilience scores reported to climate variability in Anolaima, Colombia was evaluated. Were found clustering associated with management and cellulolytic bacteria and fungi abundances. No differences found in diversity of phosphate solubilizing or nitrogen-fixing microorganisms, related to management. The diversity of microbial functional groups was affected by the climatic condition of sampling season. Management was relevant in relationships between resilience scores to climate variability and cellulolytic microorganisms; in ecological agroecosystems, biodiversity knowledge, agroecological main structure, and the participation of farmers in organizations were important

Evaluation of impacts of potato crops and livestock farming in Neotropical high Andean Páramo soils, Colombia

Páramos are Neotropical ecosystems that result from insular formations dominated by tufted hair grasses and shrubs, and are located above the continuous forest track and below the perpetual snowline of the highest peaks in the Northern Andes. The aim of this research was to check the reliability of the hypothesis that the potato cultivation and livestock farming activities modify the quality of Páramo soils. For this, soil samples were taken from soil used with three different purposes at two different heights: Páramo with the least possible intervention, and Páramo where the activities of potato cropping and livestock farming were carried out; from these, and that have been determined to have physicochemical properties, abundance of functional groups of microorganisms (nitrogen-fixing, phosphate solubilizers, cellulolytic microorganisms), and enzymatic activities (urease, protease, β-glucosidase, acid, and alkaline phosphatase). The gravimetric humidity, apparent density, organic carbon, cation exchange capacity, urease, acid phosphatase, and β-glucosidase showed statistically significant differences (P &lt; 0.05), indicating that there is a change in the quality of the soil that is exposed to agricultural activities. As for microorganisms the hypothesis was not confirmed; there are warning signs for the future in the case of continuing with these practices, but there are no significant differences.

Linking microbial community composition to hydrogeochemistry in the western Hetao Basin: Potential importance of ammonium as an electron donor during arsenic mobilization

Various functional groups of microorganisms and related biogeochemical processes are likely to control arsenic (As) mobilization in groundwater systems. However, spatially-dependent correlations between microbial community composition and geochemical zonation along groundwater flow paths are not fully understood, especially with respect to arsenic mobility. The western Hetao Basin was selected as the study area to address this limitation, where groundwater flows from a proximal fan (geochemical-group I: low As, oxidizing), through a transition area (geochemical-group II: moderate As, moderately-reducing) and then to a flat plain (geochemical-group III: high As, reducing). High-throughput Illumina 16S rRNA gene sequencing showed that the microbial community structure in the proximal fan included bacteria affiliated with organic carbon degradation and nitrate-reduction or even nitrate-dependant Fe(II)-oxidation, mainly resulting in As immobilization. In contrast, for the flat plain, high As groundwater contained Fe(III)- and As(V)-reducing bacteria, consistent with current models on As mobilization driven via reductive dissolution of Fe(III)/As(V) mineral assemblages. However, Spearman correlations between hydrogeochemical data and microbial community compositions indicated that ammonium as a possible electron donor induced reduction of Fe oxide minerals, suggesting a wider range of metabolic pathways (including ammonium oxidation coupled with Fe(III) reduction) driving As mobilization in high As groundwater systems.

Effect of aluminium oxide nano- and microparticles on the functional groups of microorganisms of activated sludge

Effect of aluminium oxide nano- and microparticles on the functional groups of microorganisms of activated sludge

ESTRATEGIAS DE CONTROL BIOLÓGICO UTILIZADAS PARA EL MANEJO DE LA ANTRACNOSIS CAUSADA POR Colletotrichum gloeosporioides EN FRUTOS DE MANGO: UNA REVISIÓN SISTEMÁTICA

&lt;p&gt;The mango (&lt;em&gt;Mangifera indica&lt;/em&gt; L.) is one of the most produced tropical fruits in the world, however, during post-harvest it is affected by pathogens such as &lt;em&gt;Colletotrichum gloeosporioides&lt;/em&gt;, which causes mango anthracnose. Synthetic fungicides are generally used to control this disease, but prolonged use can cause health and environmental effects; Therefore, biological control emerges as an alternative for the management of this disease, given that it is considered an effective and safe technique. The objective of this study was to describe the biological control strategies used for the management of anthracnose caused by &lt;em&gt;C. gloeosporioides&lt;/em&gt; in mango fruits from a systematic review of the scientific literature. The ScienceDirect, Scopus and Scholar Google databases were used. It was found that the largest number of publications were made in 2013 and 2017, with Ataúlfo and Tommy Atkins as the most studied mango varieties and Mexico was the country with the highest number of articles reported. The most studied biological control mechanism was the effect of functional groups of microorganisms on mycelial growth and the highest percentages of inhibition were reported for this mechanism, although the greatest number of reports on control mechanisms were of the category of antagonistic microorganisms. It is concluded that knowledge about the mechanisms used to control anthracnose will allow adopting more effective, practical and reliable measures; thus, managing to maintain mango quality during the storage, distribution and marketing period.&lt;/p&gt;