RESUMEN
Monensin (MON) is a coccidiostat used as a growth promoter that can reach the environment through fertilization with manure from farm animals. To verify whether field-relevant concentrations of this drug negatively influence the structure and activity of tropical soil bacteria, plate counts, CO2 efflux measurements, phospholipid fatty acids (PLFA) and community-level physiological profiling (CLPP) profiles were obtained for soil microcosms exposed to 1 or 10 mg kg-1 of MON across 11 days. Although 53% (1 mg kg-1) to 40% (10 mg kg-1) of the MON concentrations added to the microcosms dissipated within 5 days, a subtle concentration-dependent decrease in the number of culturable bacteria (<1 log CFU g-1), reduced (-20 to -30%) or exacerbated (+25%) soil CO2 effluxes, a marked shift of non-bacterial fatty acids, and altered respiration of amines (1.22-fold decrease) and polymers (1.70-fold increase) were noted in some of the treatments. These results suggest that MON quickly killed some microorganisms and that the surviving populations were selected and metabolically stimulated. Consequently, MON should be monitored in agronomic and environmental systems as part of One Health efforts.
Asunto(s)
Consorcios Microbianos/efectos de los fármacos , Monensina/toxicidad , Microbiología del Suelo , Contaminantes del Suelo/toxicidad , Drogas Veterinarias/toxicidad , Bacterias/efectos de los fármacos , Bacterias/metabolismo , Dióxido de Carbono/metabolismo , Costa Rica , Relación Dosis-Respuesta a Droga , Ácidos Grasos/metabolismo , Ionóforos/toxicidad , Fosfolípidos/metabolismoRESUMEN
Lindane is an organochlorine pesticide that, due to its persistence in the environment, is still detected in different matrices. Bioremediation using actinobacteria consortia proved to be promising for the restoration of contaminated soils. Another alternative to remove xenobiotics is to use agricultural residues, which stimulates microbial activity, increasing its capacity to degrade organic pollutants. The present work studies the coupling of sugarcane bagasse biostimulation and bioaugmentation with the actinobacteria consortium composed of Streptomyces sp. A2, A5, A11 and M7 on lindane removal in different soil types. In this sense, factorial designs with three factors (proportion and size of sugarcane bagasse particles, and moisture content) were employed. A response optimizer identified the combination of factors levels that jointly allowed obtaining the maximum lindane removal in the evaluated conditions. In the optimal conditions, the effect of the bioremediation process on soil microbiota was studied by evaluating different parameters. The highest lindane removal percentages were detected in biostimulated microcosms bioaugmented with the microbial consortium, which were accompanied by a decrease in lindane half-life respect to the controls. Also, the bioaugmentation of biostimulated microcosms increased the microbial counts and enhanced soil enzymatic activities, corroborating the bioremediation process efficiency. The survival of the four actinobacteria at the end of the assay confirmed the ability of all Streptomyces strains to colonize amended soils. Bioremediation by simultaneous application of biostimulation with sugarcane bagasse and bioaugmentation with the actinobacteria consortium, in the optimized conditions, represents an efficient strategy to restore lindane contaminated soils.
Asunto(s)
Hexaclorociclohexano/aislamiento & purificación , Hexaclorociclohexano/metabolismo , Contaminantes del Suelo/aislamiento & purificación , Contaminantes del Suelo/metabolismo , Suelo/química , Streptomyces/efectos de los fármacos , Streptomyces/metabolismo , Biodegradación Ambiental/efectos de los fármacos , Celulosa/química , Celulosa/farmacología , Consorcios Microbianos/efectos de los fármacos , Saccharum/químicaRESUMEN
Antimicrobial resistance (AMR) is a serious threat to global public health, but obtaining representative data on AMR for healthy human populations is difficult. Here, we use metagenomic analysis of untreated sewage to characterize the bacterial resistome from 79 sites in 60 countries. We find systematic differences in abundance and diversity of AMR genes between Europe/North-America/Oceania and Africa/Asia/South-America. Antimicrobial use data and bacterial taxonomy only explains a minor part of the AMR variation that we observe. We find no evidence for cross-selection between antimicrobial classes, or for effect of air travel between sites. However, AMR gene abundance strongly correlates with socio-economic, health and environmental factors, which we use to predict AMR gene abundances in all countries in the world. Our findings suggest that global AMR gene diversity and abundance vary by region, and that improving sanitation and health could potentially limit the global burden of AMR. We propose metagenomic analysis of sewage as an ethically acceptable and economically feasible approach for continuous global surveillance and prediction of AMR.
Asunto(s)
Bacterias/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple/genética , Genes Bacterianos , Metagenoma , Aguas del Alcantarillado/microbiología , África , Asia , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Monitoreo Epidemiológico , Europa (Continente) , Humanos , Metagenómica/métodos , Consorcios Microbianos/efectos de los fármacos , Consorcios Microbianos/genética , América del Norte , Oceanía , Salud Poblacional , Factores Socioeconómicos , América del SurRESUMEN
The gut microbiome has a significant impact on host health, especially at the metabolic level. Dietary compounds arriving at the colon have a large influence on the composition of the gut microbiome. High fiber diets have been associated to health benefits that are mediated in great part by short chain fatty acids (SCFA). Gut microbial interactions are relevant for the utilization of complex carbohydrates in the gut microbiome. In this work we characterized the utilization of two dietary polysaccharides by combinations of representative adult gut microbes, and the impact of their activities on a cellular inflammation model. Paired combinations of Bifidobacterium adolescentis, Bacteroides dorei, Lactobacillus plantarum, Escherichia coli and Clostridium symbiosum were grown in inulin or xylan as carbon source. Their relative abundance, substrate consumption and major SCFAs produced were determined. Higher cell growth was observed during inulin consumption, and B. adolescentis and L. plantarum were dominant in co-cultures. The co-culture of B. dorei and C. symbiosum was dominant in xylan. In several cases the combined bacterial growth was lower in co-cultures than monocultures, with a few exceptions of synergistic growth between microorganisms. Inulin fermentation resulted in larger acetate and lactate concentrations, and several combinations grown in xylan containing C. symbiosum were characterized by high amounts of butyrate. These microbial consortia were scaled to batch bioreactor fermentations reaching high cell densities and similar profiles to co-culture experiments. Interestingly, a microbial combination producing high amounts of butyrate was able to reduce IL-8 expression in HT-29 cells co-incubated with TNFα. In summary, this work shows that microbial interactions during the utilization of dietary polysaccharides are complex and substrate dependent. Moreover, certain combinations deploy potent anti-inflammatory effects, which are independent of individual microbial growth, and could be mediated in part by higher butyrate production.
Asunto(s)
Antiinflamatorios , Productos Biológicos , Fibras de la Dieta/metabolismo , Consorcios Microbianos , Antiinflamatorios/metabolismo , Antiinflamatorios/farmacología , Productos Biológicos/metabolismo , Productos Biológicos/farmacología , Reactores Biológicos/microbiología , Butiratos/análisis , Butiratos/metabolismo , Técnicas de Cocultivo , Citocinas/análisis , Citocinas/metabolismo , Fermentación , Células HT29 , Humanos , Inflamación/metabolismo , Consorcios Microbianos/efectos de los fármacos , Consorcios Microbianos/fisiología , Interacciones Microbianas , PrebióticosRESUMEN
The microbial diversity and functioning around oceanic islands is poorly described, despite its importance for ecosystem homeostasis. Here, we aimed to verify the occurrence of microbe-driven phenanthrene co-oxidation in the seawater surrounding the Trindade Island (Brazil). We also used Next-Generation Sequencing to evaluate the effects of aliphatic and polycyclic aromatic hydrocarbons (PAHs) on these microbial community assemblies. Microcosms containing seawater from the island enriched with either labelled (9-14C) or non-labelled phenanthrene together with hexadecane, weathered oil, fluoranthene or pyrene, and combinations of these compounds were incubated. Biodegradation of phenanthrene-9-14C was negatively affected in the presence of weathered oil and PAHs but increased in the presence of hexadecane. PAH contamination caused shifts in the seawater microbial community-from a highly diverse one dominated by Alphaproteobacteria to less diverse communities dominated by Gammaproteobacteria. Furthermore, the combination of PAHs exerted a compounded negative influence on the microbial community, reducing its diversity and thus functional capacity of the ecosystem. These results advance our understanding of bacterial community dynamics in response to contrasting qualities of hydrocarbon contamination. This understanding is fundamental in the application and monitoring of bioremediation strategies if accidents involving oil spillages occur near Trindade Island and similar ecosystems.
Asunto(s)
Bacterias/efectos de los fármacos , Bacterias/metabolismo , Hidrocarburos/efectos adversos , Consorcios Microbianos/efectos de los fármacos , Consorcios Microbianos/fisiología , Fenantrenos/metabolismo , Agua de Mar/microbiología , Alcanos , Alphaproteobacteria/efectos de los fármacos , Alphaproteobacteria/metabolismo , Bacterias/clasificación , Bacterias/genética , Biodegradación Ambiental , Biodiversidad , Brasil , ADN Bacteriano/genética , Ecosistema , Gammaproteobacteria/efectos de los fármacos , Gammaproteobacteria/metabolismo , Secuenciación de Nucleótidos de Alto Rendimiento , Islas , Metagenómica , Consorcios Microbianos/genética , Contaminación por Petróleo/efectos adversos , Hidrocarburos Policíclicos Aromáticos/farmacología , Pirenos , ARN Ribosómico 16S/metabolismo , Contaminantes del AguaRESUMEN
This study investigated the microbial colonization of maxillofacial prostheses and support tissues using the Checkerboard DNA-DNA hybridization method, and the efficacy of 0.12% chlorhexidine gluconate, 10% Ricinus communis solutions, or brushing, on colony forming unit (CFU) reduction in monospecies biofilms (Candida glabrata, Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa) formed on two silicones (MDX 4-4210 and Bio-Skin). Biofilm was harvested from 43 maxillofacial prosthesis wearers for detection of 38 species of microorganisms. The CFU counts of the six above mentioned species were recorded after using the hygiene protocols. All 38 investigated species were identified in prostheses and tissues, with a higher prevalence in the prostheses. 0.12% chlorhexidine gluconate immersion showed the greatest antimicrobial effectiveness, followed by mechanical brushing protocols. MDX 4-4210 silicone produced lower CFU counts than Bio-Skin.
Asunto(s)
Antiinfecciosos/farmacología , Biopelículas/efectos de los fármacos , Clorhexidina/análogos & derivados , Prótesis Maxilofacial/microbiología , Consorcios Microbianos/genética , Extractos Vegetales/farmacología , Cepillado Dental , Adhesión Bacteriana/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Clorhexidina/farmacología , Recuento de Colonia Microbiana , Dimetilpolisiloxanos/química , Femenino , Genómica , Humanos , Masculino , Consorcios Microbianos/efectos de los fármacos , Ricinus/química , Elastómeros de Silicona/química , Siliconas/química , Propiedades de Superficie , Resultado del TratamientoRESUMEN
The use of biopurification systems can mitigate the effects of pesticide contamination on farms. The primary aim of this study was to evaluate the effect of pesticide dissipation on microbial communities in a pilot biopurification system. The pesticide dissipation of atrazine, chlorpyrifos and iprodione (35 mg kg-1 active ingredient [a.i.]) and biological activity were determined for 40 days. The microbial communities (bacteria, actinomycetes and fungi) were analyzed using denaturing gradient gel electrophoresis (DGGE). In general, pesticide dissipation was the highest by day 5 and reached 95%. The pesticides did not affect biological activity during the experiment. The structure of the actinomycete and bacterial communities in the rhizosphere was more stable during the evaluation than that in the communities in the control without pesticides. The rhizosphere fungal communities, detected using DGGE, showed small and transitory shifts with time. To conclude, rhizosphere microbial communities were not affected during pesticide dissipation in a pilot biopurification system.
Asunto(s)
Bacterias/efectos de los fármacos , Hongos/efectos de los fármacos , Consorcios Microbianos/efectos de los fármacos , Plaguicidas/toxicidad , Eliminación de Residuos Líquidos/métodos , Actinomyces/efectos de los fármacos , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/análisis , Aminoimidazol Carboxamida/toxicidad , Atrazina/análisis , Atrazina/toxicidad , Biodiversidad , Cloropirifos/análisis , Cloropirifos/toxicidad , Electroforesis en Gel de Gradiente Desnaturalizante , Hidantoínas/análisis , Hidantoínas/toxicidad , Plaguicidas/análisisRESUMEN
The concept of heteroresistance refers to the heterogeneous susceptibility to an antimicrobial drug in a microorganism population, meaning that some clones may be resistant and others are susceptible. This phenomenon has been widely studied in bacteria, but little attention has been given to its expression in fungi. We review the available literature on heteroresistance in fungi and invite the reader to recognise this phenomenon as a fungal mechanism to adapt to environmental stress, which may interfere both in resistance and virulence. Finally, heteroresistance may explain the treatment failures to eradicate mycosis in some patients treated with a seemingly appropriate antifungal.
Asunto(s)
Antifúngicos/farmacología , Farmacorresistencia Fúngica , Hongos/efectos de los fármacos , Consorcios Microbianos/efectos de los fármacos , Antifúngicos/uso terapéutico , Hongos/patogenicidad , Hongos/fisiología , Humanos , Pruebas de Sensibilidad Microbiana , Micosis/tratamiento farmacológico , Micosis/microbiología , VirulenciaRESUMEN
Biodegradation of phenolic compounds in bioreactors is well documented, but the changes in the bacterial populations dynamics during degradation were not that often. A glass bubble column used as reactor was inoculated with activated sludge, spiked with 2-chlorophenol, phenol and m-cresol after 28 days and maintained for an additional 56 days, while the 16S rRNA gene from metagenomic DNA was monitored. Proteobacteria (68.1%) dominated the inoculum, but the bacterial composition changed rapidly. The relative abundance of Bacteroidetes and Firmicutes decreased from 4.8 and 9.4 to <0.1 and 0.2% respectively, while that of Actinobacteria and TM7 increased from 4.8 and 2.0 to 19.2 and 16.1% respectively. Phenol application increased the relative abundance of Proteobacteria to 94.2% (mostly Brevundimonas 17.6%), while that of Bacteroidetes remained low (1.2%) until day 42. It then increased to 47.3% (mostly Leadbetterella 46.9%) at day 84. It was found that addition of phenolic compounds did not affect the relative abundance of the Alphaproteobacteria initially, but it decreased slowly while that of the Bacteroidetes increased towards the end.
Asunto(s)
Bacterias/efectos de los fármacos , Bacterias/metabolismo , Biodegradación Ambiental , Reactores Biológicos , Consorcios Microbianos/efectos de los fármacos , Fenoles/metabolismo , Fenoles/farmacología , Aguas del Alcantarillado/microbiología , Actinobacteria/clasificación , Actinobacteria/efectos de los fármacos , Actinobacteria/genética , Actinobacteria/fisiología , Bacterias/clasificación , Bacterias/genética , Bacteroidetes/clasificación , Bacteroidetes/efectos de los fármacos , Bacteroidetes/genética , Bacteroidetes/fisiología , Clorofenoles/metabolismo , Clorofenoles/farmacología , Cresoles/metabolismo , Cresoles/farmacología , Secuenciación de Nucleótidos de Alto Rendimiento , Metagenómica , Consorcios Microbianos/genética , Consorcios Microbianos/fisiología , Fenol/metabolismo , Fenol/farmacología , Proteobacteria/clasificación , Proteobacteria/efectos de los fármacos , Proteobacteria/genética , Proteobacteria/fisiología , ARN Ribosómico 16S , Aguas del Alcantarillado/análisisRESUMEN
Biopurification systems (BPS) are design to remove pesticides from agricultural wastewater. This work assays for the first time the potential effect of an antibiotic of agricultural use (oxytetracycline, OTC) on the performance of a biomixture (biologically active core of BPS), considering that antibiotic-containing wastewaters are also produced in agricultural labors. The respiration of the biomixture was stimulated in the presence of increasing doses of OTC (≥100mgkg-1), and only slightly increased with lower doses (≤10mgkg-1). When co-applied during the removal of chlorpyrifos, OTC increased chlorpyrifos mineralization rates at low doses, resembling a hormetic effect. The biomixture was also able to remove three herbicides (atrazine, ametryn and linuron) with half-lives of 24.3 d, 43.9 d and 30.7 d; during co-application of OTC at a biomixture-relevant concentration, only the removal of ametryn was significantly inhibited, increasing its half-life to 92.4 d. Ecotoxicological assays revealed that detoxification takes place in the biomixture during the removal of herbicides in the presence of OTC. Overall results suggest that co-application of OTC in a biomixture does not negatively affect the performance of the matrix in every case; moreover, the co-application of this antibiotic could improve the mineralization of some pesticides.
Asunto(s)
Cloropirifos/análisis , Herbicidas/análisis , Oxitetraciclina/química , Aguas Residuales/química , Contaminantes Químicos del Agua/análisis , Agricultura , Animales , Biodegradación Ambiental , Cloropirifos/toxicidad , Daphnia/efectos de los fármacos , Herbicidas/toxicidad , Consorcios Microbianos/efectos de los fármacos , Modelos Teóricos , Pruebas de Toxicidad Aguda , Contaminantes Químicos del Agua/toxicidadRESUMEN
The insecticide chlordecone applied for decades in banana plantations currently contaminates 20,000 ha of arable land in the French West Indies. Although the impact of various pesticides on soil microorganisms has been studied, chlordecone toxicity to the soil microbial community has never been assessed. We investigated in two different soils (sandy loam and silty loam) exposed to different concentrations of CLD (D0, control; D1 and D10, 1 and 10 times the agronomical dose) over different periods of time (3, 7, and 32 days): (i) the fate of chlordecone by measuring (14)C-chlordecone mass balance and (ii) the impact of chlordecone on microbial community structure, abundance, and function, using standardized methods (-A-RISA, taxon-specific quantitative PCR (qPCR), and (14)C-compounds mineralizing activity). Mineralization of (14)C-chlordecone was inferior below 1 % of initial (14)C-activity. Less than 2 % of (14)C-activity was retrieved from the water-soluble fraction, while most of it remained in the organic-solvent-extractable fraction (75 % of initial (14)C-activity). Only 23 % of the remaining (14)C-activity was measured in nonextractable fraction. The fate of chlordecone significantly differed between the two soils. The soluble and nonextractable fractions were significantly higher in sandy loam soil than in silty loam soil. All the measured microbiological parameters allowed discriminating statistically the two soils and showed a variation over time. The genetic structure of the bacterial community remained insensitive to chlordecone exposure in silty loam soil. In response to chlordecone exposure, the abundance of Gram-negative bacterial groups (ß-, γ-Proteobacteria, Planctomycetes, and Bacteroidetes) was significantly modified only in sandy loam soil. The mineralization of (14)C-sodium acetate and (14)C-2,4-D was insensitive to chlordecone exposure in silty loam soil. However, mineralization of (14)C-sodium acetate was significantly reduced in soil microcosms of sandy loam soil exposed to chlordecone as compared to the control (D0). These data show that chlordecone exposure induced changes in microbial community taxonomic composition and function in one of the two soils, suggesting microbial toxicity of this organochlorine.
Asunto(s)
Clordecona/toxicidad , Insecticidas/toxicidad , Consorcios Microbianos/efectos de los fármacos , Microbiología del Suelo , Contaminantes del Suelo/toxicidad , Ácido 2,4-Diclorofenoxiacético/química , Bacterias , Radioisótopos de Carbono , Clordecona/análisis , Ecotoxicología , Insecticidas/análisis , Musa , Acetato de Sodio , Suelo/química , Contaminantes del Suelo/análisis , Indias OccidentalesRESUMEN
The widespread of Fe(III)-reducing microorganisms in natural ecosystems of Ecuador of La Favorita, Tungurahua volcano and Papallacta areas was experimentally proved. High efficiency of microbial precipitation of soluble iron compounds was also demonstrated. Obtained results indicate the potential ability of Fe(III)-reducing microorganisms to influence the formation of carbon and iron vector fluxes in ecosystems, as well as development of effective biotechnologies of water purification from iron compounds.
Asunto(s)
Bacterias/metabolismo , Consorcios Microbianos/efectos de los fármacos , Microbiología del Suelo , Contaminantes del Suelo/química , Bacterias/efectos de los fármacos , Bacterias/crecimiento & desarrollo , Ciclo del Carbono , Cationes , Ecosistema , Ecuador , Floculación , Hierro/química , Hierro/metabolismo , Hierro/toxicidad , Consorcios Microbianos/fisiología , Oxidación-Reducción , Contaminantes del Suelo/metabolismo , Contaminantes del Suelo/toxicidad , Solubilidad , Erupciones VolcánicasRESUMEN
Microbial communities of the Ecuadorian Andes and volcano Tungurahua were shown to be super resistant to representative toxic metals. Maximum permissible concentrations of toxic metals were 100 ppm of Hg2+, 500 ppm of Co2+ and Ni2+, 1000 and 1500 ppm of Cr(VI), 10000 and 20000 ppm of Cu2+. The effect of metal concentration increasing on the biomass growth, CO2 and H2 synthesis was investigated. Two types of response of microbial communities on the increasing of toxic metals concentrations were discovered. The first type of response is the catastrophic inhibition of microbial growth. The second type of response is the absence of microbial growth inhibition at certain metal concentration gradient. The succession of qualitative structure of Ecuadorian microbial communities was shown for the first time. Bacteria, yeasts and finally fungi consistently dominate in the microbial community at the Cu2+ concentration raising. Microorganisms resistant to ultra-high concentrations of toxic metals (e.g., 3000 ... 20000 ppm of Cu2+) were isolated from Ecuadorian ecosystems. These microorganisms are able to accumulate toxic metals.
Asunto(s)
Bacterias/efectos de los fármacos , Hongos/efectos de los fármacos , Consorcios Microbianos/efectos de los fármacos , Microbiología del Suelo , Contaminantes del Suelo/toxicidad , Bacterias/crecimiento & desarrollo , Bacterias/metabolismo , Dióxido de Carbono/metabolismo , Cationes Bivalentes , Cromo/metabolismo , Cromo/toxicidad , Cobalto/metabolismo , Cobalto/toxicidad , Cobre/metabolismo , Cobre/toxicidad , Farmacorresistencia Bacteriana , Farmacorresistencia Fúngica , Ecosistema , Ecuador , Hongos/crecimiento & desarrollo , Hongos/metabolismo , Hidrógeno/metabolismo , Mercurio/metabolismo , Mercurio/toxicidad , Consorcios Microbianos/fisiología , Níquel/metabolismo , Níquel/toxicidad , Contaminantes del Suelo/metabolismo , Erupciones VolcánicasRESUMEN
A heavy-metal resistant bacterial consortium was obtained from a contaminated river in São Paulo, Brazil and utilized for the design of a fixed-bed column for the removal of copper. Prior to the design of the fixed-bed bioreactor, the copper removal capacity by the live consortium and the effects of copper in the consortium biofilm formation were investigated. The Langmuir model indicated that the sorption capacity of the consortium for copper was 450.0 mg/g dry cells. The biosorption of copper into the microbial biomass was attributed to carboxyl and hydroxyl groups present in the microbial biomass. The effect of copper in planktonic cells to form biofilm under copper rich conditions was investigated with confocal microscopy. The results revealed that biofilm formed after 72 h exposure to copper presented a reduced thickness by 57% when compared to the control; however 84% of the total cells were still alive. The fixed-bed bioreactor was set up by growing the consortium biofilm on granular activated carbon (GAC) and analyzed for copper removal. The biofilm-GAC (BGAC) column retained 45% of the copper mass present in the influent, as opposed to 17% in the control column that contained GAC only. These findings suggest that native microbial communities in sites contaminated with heavy metals can be immobilized in fixed-bed bioreactors and used to treat metal contaminated water.
Asunto(s)
Reactores Biológicos/microbiología , Cobre/aislamiento & purificación , Consorcios Microbianos , Adsorción , Bacterias/efectos de los fármacos , Bacterias/crecimiento & desarrollo , Bacterias/ultraestructura , Biodegradación Ambiental/efectos de los fármacos , Biopelículas/efectos de los fármacos , Brasil , Carbón Orgánico/farmacología , Concentración de Iones de Hidrógeno , Cinética , Consorcios Microbianos/efectos de los fármacos , Espectrometría por Rayos X , Espectroscopía Infrarroja por Transformada de Fourier , TemperaturaRESUMEN
34 strains of aerobic chemoorganotrophic microorganisms were isolated from 23 soil and plant samples selected from highland biotopes of Ecuador-Andes massif (Papallacta, 4020 m), ash at the foot of the volcano Tungurahua, mountainous jungle (La Favorita, 1600 m), as well as in humid tropic botanical garden (state Puyo, 950 m). In mountain jungle samples the high number of bacteria--10(5)-10(7) CFU/g of sample were represented by 2-5 morphotypes. In highland (4020 m) samples the bacterial counts made from 10(2) to 10(7) CFU/g of sample. The current study describes resistance of isolated strains to high salinity, UV radiation and toxic metal ions. The majority of isolated strains were halotolerant. Isolates from volcanic ash showed high resistance level to UV radiation--LD99,99 made 1000-1440 J/m2; resistance level for isolates from the soil of Puyo Botanical Garden and isolates from rock lichen (Papallacta) LD99,99 made 1160 and 800 J/m2 respectively. Strains isolated from mountain jungle (La Favorita) showed lower UV-resistance. In highland biotopes of Ecuador occurred bacteria resistant to toxic metal ions. The highest resistance to Hg2+ was shown by isolate of lichen from mountain jungle, the maximal growth concentration was 0.025 g/L; to Cr(VI)--by isolate from lichen rock massif--3,0 g/L. Correlation between metal-resistance, halotolerace and UV resistance for studied strains was not detected, probably because of different microbial cell damage/repair mechanisms under the action of these factors.
Asunto(s)
Bacterias/crecimiento & desarrollo , Metales Pesados/toxicidad , Consorcios Microbianos/fisiología , Microbiología del Suelo , Contaminantes del Suelo/toxicidad , Aerobiosis , Altitud , Bacterias/efectos de los fármacos , Bacterias/efectos de la radiación , Farmacorresistencia Bacteriana , Ecuador , Consorcios Microbianos/efectos de los fármacos , Consorcios Microbianos/efectos de la radiación , Viabilidad Microbiana/efectos de los fármacos , Plantas/microbiología , Salinidad , Tolerancia a la Sal/fisiología , Cloruro de Sodio/farmacología , Clima Tropical , Rayos Ultravioleta , Erupciones VolcánicasRESUMEN
The effect of pre-treated peat moss on the ability of a sulfate-reducing microbial consortium to remove chromium and lead in solution was evaluated. The most active bacterial community (235.7 mmol H2S/g VSS) was selected from among eight consortia. The peat moss was pre-treated with different HCl concentrations and contact times. The best combination of treatments was 20% HCl for 10 min. The constant substrate affinity Ks was 740 mg COD/L and the ratio COD/SO4(2-) was 0.71. At pH 5, higher production of biogenic sulfide was observed. The up-flowpacked bed bioreactor operated at a flow of 8.3 mL/min for 180 h to obtain removal efficiency (by sulfate-reducing activity) of 90% lead and 65% chromium. It is important to consider that peat moss is a natural adsorbent that further influences the removal efficiency of metal ions.
Asunto(s)
Carbono/farmacología , Cromo/aislamiento & purificación , Plomo/aislamiento & purificación , Consorcios Microbianos , Sphagnopsida/química , Sulfatos/metabolismo , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Biodegradación Ambiental/efectos de los fármacos , Reactores Biológicos/microbiología , Ácido Clorhídrico/farmacología , Sulfuro de Hidrógeno/metabolismo , Concentración de Iones de Hidrógeno , Cinética , Consorcios Microbianos/efectos de los fármacos , Oxidación-Reducción/efectos de los fármacos , Suelo/química , Factores de Tiempo , Eliminación de Residuos Líquidos , Contaminantes Químicos del Agua/aislamiento & purificaciónRESUMEN
The effects of repeated atrazine application (40 mg a.i.kg(-1)) on its degradation, microbial communities and enzyme activities were studied in a peat based biomixture composed by straw, soil and peat in the volumetric proportions of 2:1:1 that can be used in on-farm biopurification system. Atrazine removal efficiency was high (96%, 78% and 96%) after each atrazine application and did not show a lag phase. Microbial enzyme activities were reduced significantly with atrazine application but rapidly recovered. Microbial diversity obtained by BiologEcoplate was similar after the first and second atrazine application. However, an inhibitory effect was observed after the third application. After each atrazine application, culturable fungi were reduced, but rapidly recovered without significant changes in culturable bacteria and actinomycetes compared to the control. Denaturing gradient gel electrophoresis (DGGE) patterns demonstrated that microbial community structure remained relatively stable in time when compared to the controls. In conclusion, our results demonstrated that after successive ATZ applications, the peat based biomixture had a good degradation capacity. Moreover, microbiological assays demonstrated the robustness of the peat based biomixture from a microbiological point of view to support pesticide degradation.
Asunto(s)
Atrazina/análisis , Atrazina/química , Consorcios Microbianos/efectos de los fármacos , Microbiología del Suelo , Contaminantes del Suelo/análisis , Actinobacteria/clasificación , Actinobacteria/efectos de los fármacos , Bacterias/clasificación , Bacterias/efectos de los fármacos , Biodegradación Ambiental , Electroforesis en Gel de Gradiente Desnaturalizante , Hongos/clasificación , Hongos/efectos de los fármacos , Plaguicidas/química , Reacción en Cadena de la Polimerasa , ARN Ribosómico 16S/genética , Suelo , Contaminantes del Suelo/metabolismo , Factores de TiempoRESUMEN
AIM: To evaluate clinically the antibacterial effects of root canal treatment procedures using molecular microbiology analyses. METHODOLOGY: Samples were taken from 14 necrotic root canals of teeth with apical periodontitis before (S1) and after instrumentation with NaOCl irrigation (S2), a final rinse with chlorhexidine (CHX) (S3) and then one-week interappointment medication with calcium hydroxide/CHX paste (S4). The parameters examined included the following: incidence of positive broad-range PCR results for bacterial presence; impact on bacterial community structures evaluated by PCR-Denaturing Gradient Gel Electrophoresis (DGGE); quantitative bacterial reduction determined by real-time PCR; and identification of bacterial persisters by cloning and sequencing. Data from the different tests were subjected to statistical analyses and diversity indicator calculations. RESULTS: All S1 samples were positive for bacteria in all tests. Treatment procedures promoted a decrease in microbial diversity and significantly reduced the incidence of positive results and the bacterial counts (P < 0.05). In general, each subsequent treatment step improved disinfection. No specific taxon or community pattern was associated with post-treatment samples. CONCLUSION: Supplementary steps consisting of a final rinse with CHX followed by calcium hydroxide interappointment medication promoted further decrease in the bacterial bioburden to levels significantly below those achieved by the chemomechanical procedures alone. Because the long-term outcome of root canal treatment is dependent upon maximal bacterial reduction, the present results are of clinical relevance.
Asunto(s)
Antiinfecciosos Locales/uso terapéutico , Hidróxido de Calcio/uso terapéutico , Clorhexidina/análogos & derivados , Aleaciones Dentales , Desinfección/métodos , Níquel , Irrigantes del Conducto Radicular/uso terapéutico , Preparación del Conducto Radicular/instrumentación , Hipoclorito de Sodio/uso terapéutico , Titanio , Carga Bacteriana/efectos de los fármacos , Biodiversidad , Clorhexidina/uso terapéutico , Electroforesis en Gel de Gradiente Desnaturalizante , Aleaciones Dentales/química , Pulpa Dental/microbiología , Cavidad Pulpar/microbiología , Necrosis de la Pulpa Dental/microbiología , Necrosis de la Pulpa Dental/terapia , Ácido Edético/uso terapéutico , Bacterias Gramnegativas/clasificación , Bacterias Gramnegativas/genética , Bacterias Grampositivas/clasificación , Bacterias Grampositivas/genética , Humanos , Consorcios Microbianos/efectos de los fármacos , Biología Molecular , Níquel/química , Periodontitis Periapical/microbiología , Periodontitis Periapical/terapia , ARN Bacteriano/análisis , ARN Ribosómico 16S/análisis , Reacción en Cadena en Tiempo Real de la Polimerasa , Preparación del Conducto Radicular/métodos , Análisis de Secuencia de ARN , Capa de Barro Dentinario , Titanio/químicaRESUMEN
Glyphosate-based formulations are among the most widely used herbicides in the world. The effect of the formulation Glifosato Atanor(®) on freshwater microbial communities (phytoplankton, bacterioplankton, periphyton and zooplankton) was assessed through a manipulative experiment using six small outdoor microcosms of small volume. Three of the microcosms were added with 3.5 mg l(-1) of glyphosate whereas the other three were left as controls without the herbicide. The treated microcosms showed a significant increase in total phosphorus, not fully explained by the glyphosate present in the Glifosato Atanor(®). Therefore, part of the phosphorus should have come from the surfactants of the formulation. The results showed significant direct and indirect effects of Glifosato Atanor(®) on the microbial communities. A single application of the herbicide caused a fast increase both in the abundance of bacterioplankton and planktonic picocyanobacteria and in chlorophyll a concentration in the water column. Although metabolic alterations related to oxidative stress were induced in the periphyton community, the herbicide favored its development, with a large contribution of filamentous algae typical of nutrient-rich systems, with shallow and calm waters. An indirect effect of the herbicide on the zooplankton was observed due to the increase in the abundance of the rotifer Lecane spp. as a consequence of the improved food availability given by picocyanobacteria and bacteria. The formulation affected directly a fraction of copepods as a target. It was concluded that the Glifosato Atanor(®) accelerates the deterioration of the water quality, especially when considering small-volume water systems.