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1.
Life Sci ; 246: 117398, 2020 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-32032647

RESUMEN

Conventional cancer therapies such as chemotherapy, radiation therapy, and immunotherapy due to the complexity of cancer have been unsuccessful in the complete eradication of tumor cells. Thus, there is a need for new therapeutic strategies toward cancer. Recently, the therapeutic role of bacteria in different fields of medicine and pharmaceutical research has attracted attention in recent decades. Although several bacteria are notorious as cancer-causing agents, recent research revealed intriguing results suggesting the bacterial potential in cancer therapy. Thus, bacterial cancer therapy is an alternative anticancer approach that has promising results on tumor cells in-vivo. Moreover, with the aid of genetic engineering, some natural or genetically modified bacterial strains can directly target hypoxic regions of tumors and secrete therapeutic molecules leading to cancer cell death. Additionally, stimulation of immune cells by bacteria, bacterial cancer DNA vaccine and antitumor bacterial metabolites are other therapeutic applications of bacteria in cancer therapy. The present study is a comprehensive review of different aspects of bacterial cancer therapy alone and in combination with conventional methods, for improving cancer therapy.


Asunto(s)
Bacterias/metabolismo , Neoplasias/terapia , Animales , Antibióticos Antineoplásicos/metabolismo , Antibióticos Antineoplásicos/uso terapéutico , Bacterias/genética , Terapia Combinada , Ingeniería Genética , Humanos , Inmunoterapia/métodos
2.
Chemosphere ; 244: 125570, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32050348

RESUMEN

In this paper, the enhancement of sodium glutamate (SG) on activity of anaerobic ammonia oxidizing (anammox) bacteria was investigated by batch tests. The results illustrated that SG played an important role in enhancing anammox bacterial activity when the SG dosage ranged from 0.50 to 1.25 mM, and the optimal SG concentration was 1.00 mM. The performance of anammox was the best and the total nitrogen removal rate (TNRR) was 138.2 mg N g-1·VSS·d-1 when the concentration of SG was 1.00 mM. The results of EPS and anammox bacterial biomass measurement indicated that protein (PN), polysaccharide (PS), total EPS and the bacterial abundance reached the maximum of 1.00 mM SG addition. Compared to the control tests, the EPS content and bacterial abundance increased by 38.2% and 75.8%, respectively. In addition, the cloning results showed that the community structure of anammox bacteria evolved in species level of Candidatus Brocadia genus under the condition of SG enhancement.


Asunto(s)
Bacterias/metabolismo , Glutamato de Sodio/metabolismo , Anaerobiosis , Biomasa , Reactores Biológicos/microbiología , Nitrógeno/metabolismo , Oxidación-Reducción
3.
Chemosphere ; 244: 125626, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32050356

RESUMEN

The aquatic plants Iris pseudacorus L., Canna indica L. and Lythrum salicaria L. have been proved to be potential choices for nitrogen removal. However, little is known about microbial diversity for the improvement of nitrogen removal (nitrification and denitrification) in stormwater bioretention cells with the above plants. In this study, batch experiments were conducted to investigate nitrogen removal, substrate layer status, and bacterial community structure to understand microbial diversity and evaluate its effects on performances of nitrogen removal. Ammonia nitrogen removal in the bioretention cell with Lythrum salicaria L. was the highest (88.1%), which was consistent with oxidation reduction potential (ORP) in the bioretention cells. Whilst, removals for both total nitrogen and nitrate were the highest in the bioretention cell with Canna indica L., which was in line with urease activity in the mentioned cells. The used plants had different impact on top 11 dominant microflora at phylum level in the used bioretention cells. Ramlibacter and Nitrosomonadaceaea were both responsible for the difference of nitrogen removal in the bioretention cells with three aquatic plants, suggesting the enhancement of the above dominant microflora could strengthen nitrogen removal in the used bioretention cells.


Asunto(s)
Nitrógeno/análisis , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/análisis , Amoníaco , Bacterias/metabolismo , Biodegradación Ambiental , Desnitrificación , Nitratos , Nitrificación , Nitrógeno/metabolismo , Plantas/metabolismo , Lluvia , Contaminantes Químicos del Agua/metabolismo
4.
World J Microbiol Biotechnol ; 36(2): 29, 2020 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-32016527

RESUMEN

Short-chain halogenated aliphatic hydrocarbons (e.g. perchloroethene, trichloroethene) are among the most toxic environmental pollutants. Perchloroethene and trichloroethene can be dechlorinated to non-toxic ethene through reductive dechlorination by Dehalococcoides sp. Bioaugmentation, applying cultures containing organohalide-respiring microorganisms, is a possible technique to remediate sites contaminated with chlorinated ethenes. Application of site specific inocula is an efficient alternative solution. Our aim was to develop site specific dechlorinating microbial inocula by enriching microbial consortia from groundwater contaminated with trichloroethene using microcosm experiments containing clay mineral as solid phase. Our main goal was to develop fast and reliable method to produce large amount (100 L) of bioactive agent with anaerobic fermentation technology. Polyphasic approach has been applied to monitor the effectiveness of dechlorination during the transfer process from bench-scale (500 mL) to industrial-scale (100 L). Gas chromatography measurement and T-RFLP (Terminal Restriction Fragment Length Polymorphism) revealed that the serial subculture of the enrichments shortened the time-course of the complete dechlorination of trichloroethene to ethene and altered the composition of bacterial communities. Complete dechlorination was observed in enrichments with significant abundance of Dehalococcoides sp. cultivated at 8 °C. Consortia incubated in fermenters at 18 °C accelerated the conversion of TCE to ethene by 7-14 days. Members of the enrichments belong to the phyla Bacteroidetes, Chloroflexi, Proteobacteria and Firmicutes. According to the operational taxonomic units, main differences between the composition of the enrichment incubated at 8 °C and 18 °C occurred with relative abundance of acetogenic and fermentative species. In addition to the temperature, the site-specific origin of the microbial communities and the solid phase applied during the fermentation technique contributed to the development of a unique microbial composition.


Asunto(s)
Anaerobiosis/fisiología , Bacterias/metabolismo , Biodegradación Ambiental , Arcilla/química , Microbiota/fisiología , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Bacteroidetes/genética , Bacteroidetes/metabolismo , Chloroflexi/genética , Chloroflexi/metabolismo , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , Fermentación , Firmicutes/genética , Firmicutes/metabolismo , Geobacter/genética , Geobacter/metabolismo , Agua Subterránea/microbiología , Consorcios Microbianos , Polimorfismo de Longitud del Fragmento de Restricción , Proteobacteria/genética , Proteobacteria/metabolismo , ARN Ribosómico 16S/genética , ARN Ribosómico 16S/aislamiento & purificación , Tricloroetileno/química , Microbiología del Agua , Contaminantes Químicos del Agua/metabolismo
5.
Cell Host Microbe ; 27(3): 345-357.e6, 2020 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-32078802

RESUMEN

Although the gut microbiome is generally symbiotic or commensal, some microbiome members become pathogenic under certain circumstances. However, the factors driving this pathogenic switch are largely unknown. Pathogenic bacteria can generate uracil that triggers host dual oxidase (DUOX) to produce antimicrobial reactive oxygen species (ROS). We show that pathogens generate uracil and ribose upon nucleoside catabolism of gut luminal uridine, which triggers not only host defenses but also inter-bacterial communication and pathogenesis in Drosophila. Uridine-derived uracil triggers DUOX-dependent ROS generation, whereas ribose induces bacterial quorum sensing (QS) and virulence gene expression. Genes implicated in nucleotide metabolism are found in pathogens but not commensal bacteria, and their genetic ablation blocks QS and the commensal-to-pathogen transition in vivo. Furthermore, commensal bacteria lack functional nucleoside catabolism, which is required to achieve gut-microbe symbiosis, but can become pathogenic by enabling nucleotide catabolism. These findings reveal molecular mechanisms governing the commensal-to-pathogen transition in different contexts of host-microbe interactions.


Asunto(s)
Bacterias/metabolismo , Bacterias/patogenicidad , Drosophila/microbiología , Percepción de Quorum , Uracilo/metabolismo , Virulencia , Animales , Proteínas Bacterianas/metabolismo , Oxidasas Duales/metabolismo , N-Glicosil Hidrolasas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Ribosa/metabolismo , Simbiosis , Uridina/metabolismo
6.
World J Microbiol Biotechnol ; 36(1): 14, 2020 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-31897771

RESUMEN

Glycogen is conventionally considered as a transient energy reserve that can be rapidly synthesized for glucose accumulation and mobilized for ATP production. However, this conception is not completely applicable to prokaryotes due to glycogen structural heterogeneity. A number of studies noticed that glycogen with small average chain length gc in bacteria has the potential to degrade slowly, which might prolong bacterial environment survival. This phenomenon was previously examined and later formulated as the durable energy storage mechanism hypothesis. Although recent research has been warming to the hypothesis, experimental validation is still missing at current stage. In this review, we summarized recent progress of the hypothesis, provided a supporting mathematical model, and explored the technical pitfalls that shall be avoided in glycogen study.


Asunto(s)
Bacterias/crecimiento & desarrollo , Glucosa/metabolismo , Glucógeno/química , Adenosina Trifosfato/metabolismo , Bacterias/química , Bacterias/metabolismo , Secuencia de Carbohidratos , Metabolismo Energético , Viabilidad Microbiana , Modelos Teóricos
7.
Microbes Environ ; 35(1)2020.
Artículo en Inglés | MEDLINE | ID: mdl-31932538

RESUMEN

Accretionary prisms are thick masses of sedimentary material scraped from the oceanic crust and piled up at convergent plate boundaries found across large regions of the world. Large amounts of anoxic groundwater and natural gas, mainly methane (CH4), are contained in deep aquifers associated with these accretionary prisms. To identify the subsurface environments and potential for CH4 production by the microbial communities in deep aquifers, we performed chemical and microbiological assays on groundwater and natural gas derived from deep aquifers associated with an accretionary prism and its overlying sedimentary layers. Physicochemical analyses of groundwater and natural gas suggested wide variations in the features of the six deep aquifers tested. On the other hand, a stable carbon isotope analysis of dissolved inorganic carbon in the groundwater and CH4 in the natural gas showed that the deep aquifers contained CH4 of biogenic or mixed biogenic and thermogenic origins. Live/dead staining of microbial cells contained in the groundwater revealed that the cell density of live microbial cells was in the order of 104 to 106| |cells| |mL-1, and cell viability ranged between 7.5 and 38.9%. A DNA analysis and anoxic culture of microorganisms in the groundwater suggested a high potential for CH4 production by a syntrophic consortium of hydrogen (H2)-producing fermentative bacteria and H2-utilizing methanogenic archaea. These results suggest that the biodegradation of organic matter in ancient sediments contributes to CH4 production in the deep aquifers associated with this accretionary prism as well as its overlying sedimentary layers.


Asunto(s)
Sedimentos Geológicos/microbiología , Agua Subterránea/microbiología , Metano/biosíntesis , Consorcios Microbianos , Anaerobiosis , Archaea/clasificación , Archaea/genética , Archaea/aislamiento & purificación , Archaea/metabolismo , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Carbono/análisis , Sedimentos Geológicos/química , Agua Subterránea/química , Hidrógeno/metabolismo , Japón , Metano/análisis , Gas Natural/análisis , ARN Ribosómico 16S/genética
8.
Microbes Environ ; 35(1)2020.
Artículo en Inglés | MEDLINE | ID: mdl-31932540

RESUMEN

Chitin amendment is an agricultural management strategy for controlling soil-borne plant disease. We previously reported an exponential decrease in chitin added to incubated upland soil. We herein investigated the transition of the bacterial community structure in chitin-degrading soil samples over time and the characteristics of chitinolytic bacteria in order to elucidate changes in the chitinolytic bacterial community structure during chitin degradation. The addition of chitin to soil immediately increased the population of bacteria in the genus Streptomyces, which is the main decomposer of chitin in soil environments. Lysobacter, Pseudoxanthomonas, Cellulosimicrobium, Streptosporangium, and Nonomuraea populations increased over time with decreases in that of Streptomyces. We isolated 104 strains of chitinolytic bacteria, among which six strains were classified as Lysobacter, from chitin-treated soils. These results suggested the involvement of Lysobacter as well as Streptomyces as chitin decomposers in the degradation of chitin added to soil. Lysobacter isolates required yeast extract or casamino acid for significant growth on minimal agar medium supplemented with glucose. Further nutritional analyses demonstrated that the six chitinolytic Lysobacter isolates required methionine (Met) to grow, but not cysteine or homocysteine, indicating Met auxotrophy. Met auxotrophy was also observed in two of the five type strains of Lysobacter spp. tested, and these Met auxotrophs used d-Met as well as l-Met. The addition of Met to incubated upland soil increased the population of Lysobacter. Met may be a factor increasing the population of Lysobacter in chitin-treated upland soil.


Asunto(s)
Bacterias/aislamiento & purificación , Bacterias/metabolismo , Quitina/farmacología , Metionina/metabolismo , Microbiota/efectos de los fármacos , Microbiología del Suelo , Bacterias/clasificación , Bacterias/genética , Quitina/análisis , Quitina/metabolismo , Lysobacter/clasificación , Lysobacter/genética , Lysobacter/aislamiento & purificación , Lysobacter/metabolismo , Filogenia , ARN Ribosómico 16S/genética , Suelo/química , Streptomyces/clasificación , Streptomyces/genética , Streptomyces/aislamiento & purificación , Streptomyces/metabolismo
9.
Chem Asian J ; 15(3): 327-337, 2020 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-31957936

RESUMEN

Microbial secondary metabolites (SMs) have long been viewed as a significant source of novel pharmaceutical and agrochemical molecules. With the increasing availability of genomic data, numerous biosynthetic gene clusters (BGCs) have been discovered. Despite the presence of tens of thousands of BGCs that can theoretically produce extremely diverse SMs, many gene clusters remain in a silent state under axenic culture conditions. Co-culture is a promising research approach as it stimulates the expression of cryptic BGCs to produce novel metabolites and also mimics natural interspecies interactions in a laboratory environment. In recent years, the roles of SMs in microbial communication have caught the attention of researchers and our understanding of microbes and their production of remarkable SMs has improved. SMs may be extensively involved in a variety of communication events among microorganisms. We herein summarize certain representative findings in the field of chemical communication involving SMs in co-culture systems.


Asunto(s)
Bacterias/química , Metabolismo Secundario , Aspergillus fumigatus/química , Aspergillus fumigatus/metabolismo , Aspergillus fumigatus/virología , Bacterias/metabolismo , Bacterias/virología , Ensamble y Desensamble de Cromatina , Óxido Nítrico/química , Óxido Nítrico/metabolismo , Streptomyces/química , Streptomyces/metabolismo , Streptomyces/virología , Virus/patogenicidad
10.
BMC Bioinformatics ; 21(1): 11, 2020 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-31918658

RESUMEN

BACKGROUND: Metabolomics time-course experiments provide the opportunity to understand the changes to an organism by observing the evolution of metabolic profiles in response to internal or external stimuli. Along with other omic longitudinal profiling technologies, these techniques have great potential to uncover complex relations between variations across diverse omic variables and provide unique insights into the underlying biology of the system. However, many statistical methods currently used to analyse short time-series omic data are i) prone to overfitting, ii) do not fully take into account the experimental design or iii) do not make full use of the multivariate information intrinsic to the data or iv) are unable to uncover multiple associations between different omic data. The model we propose is an attempt to i) overcome overfitting by using a weakly informative Bayesian model, ii) capture experimental design conditions through a mixed-effects model, iii) model interdependencies between variables by augmenting the mixed-effects model with a conditional auto-regressive (CAR) component and iv) identify potential associations between heterogeneous omic variables by using a horseshoe prior. RESULTS: We assess the performance of our model on synthetic and real datasets and show that it can outperform comparable models for metabolomic longitudinal data analysis. In addition, our proposed method provides the analyst with new insights on the data as it is able to identify metabolic biomarkers related to treatment, infer perturbed pathways as a result of treatment and find significant associations with additional omic variables. We also show through simulation that our model is fairly robust against inaccuracies in metabolite assignments. On real data, we demonstrate that the number of profiled metabolites slightly affects the predictive ability of the model. CONCLUSIONS: Our single model approach to longitudinal analysis of metabolomics data provides an approach simultaneously for integrative analysis and biomarker discovery. In addition, it lends better interpretation by allowing analysis at the pathway level. An accompanying R package for the model has been developed using the probabilistic programming language Stan. The package offers user-friendly functions for simulating data, fitting the model, assessing model fit and postprocessing the results. The main aim of the R package is to offer freely accessible resources for integrative longitudinal analysis for metabolomics scientists and various visualization functions easy-to-use for applied researchers to interpret results.


Asunto(s)
Biomarcadores/metabolismo , Metabolómica/métodos , Modelos Teóricos , Bacterias/metabolismo , Teorema de Bayes , Metaboloma
11.
J Agric Food Chem ; 68(6): 1546-1554, 2020 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-31986047

RESUMEN

Bromoxynil is an increasingly applied nitrile herbicide. Under aerobic conditions, hydration, nitrilation, or hydroxylation of the nitrile group commonly occurs, whereas under anaerobic conditions reductive dehalogenation is common. This work studied the isotope effects associated with these processes by soil cultures. The aerobic soil enrichment culture presented a significant increase in Stenotrophomonas, Pseudomonas, Chryseobacterium, Achromobacter, Azospirillum, and Arcticibacter, and degradation products indicated that nitrile hydratase was the dominant degradation route. The anaerobic culture was dominated by Proteobacteria and Firmicutes phyla with a significant increase in Dethiosulfatibacter, and degradation products indicated reductive debromination as a major degradation route. Distinct dual-isotope trends (δ13C, δ15N) were determined for the two routes: a strong inverse nitrogen isotope effect (εN = 10.56 ± 0.36‰) and an insignificant carbon isotope effect (εC = 0.37 ± 0.36‰) for the aerobic process versus a negligible effect for both elements in the anaerobic process. These trends differ from formerly reported trends for the photodegradation of bromoxynil and enable one to distinguish between the processes in the field.


Asunto(s)
Bacterias/metabolismo , Herbicidas/química , Nitrilos/química , Contaminantes del Suelo/química , Aerobiosis , Anaerobiosis , Biodegradación Ambiental , Isótopos de Carbono/química , Isótopos de Nitrógeno/química , Suelo/química , Microbiología del Suelo
12.
J Agric Food Chem ; 68(8): 2457-2466, 2020 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-31995379

RESUMEN

The influence of the rhizosphere on the abundance and diversity of antibiotic resistance genes (ARGs) has been recognized but there is a lack of consensus because of broad ranges of plant species and antibiotic concentrations across different habitats and the elusive underlying mechanisms. Here, we profiled antibiotic concentrations and resistomes in the rhizosphere and bulk soils by cultivating 10 types of crops in manure-amended agricultural soils. Rhizosphere effects altered the antibiotic resistome structure, significantly increased the absolute abundance of the antibiotic resistome, and decreased their relative abundance, contrasting previous studies. Such plantation-driven variation in ARGs resulted from the boost of bacterial lineages with negative relationships with ARGs and the constraint of the potential ARG-hosts in the rhizosphere of plants cultivated in soils with low antibiotic concentrations as the selective pressure. This mechanism is not reported previously and deepens our understanding about the rhizosphere effects on ARGs.


Asunto(s)
Antibacterianos/análisis , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Farmacorresistencia Bacteriana , Suelo/química , Agricultura , Bacterias/genética , Bacterias/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Productos Agrícolas/crecimiento & desarrollo , Rizosfera , Microbiología del Suelo
13.
BMC Bioinformatics ; 21(1): 15, 2020 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-31931703

RESUMEN

BACKGROUND: Seed and accessibility constraints are core features to enable highly accurate sRNA target screens based on RNA-RNA interaction prediction. Currently, available tools provide different (sets of) constraints and default parameter sets. Thus, it is hard to impossible for users to estimate the influence of individual restrictions on the prediction results. RESULTS: Here, we present a systematic assessment of the impact of established and new constraints on sRNA target prediction both on a qualitative as well as computational level. This is done exemplarily based on the performance of IntaRNA, one of the most exact sRNA target prediction tools. IntaRNA provides various ways to constrain considered seed interactions, e.g. based on seed length, its accessibility, minimal unpaired probabilities, or energy thresholds, beside analogous constraints for the overall interaction. Thus, our results reveal the impact of individual constraints and their combinations. CONCLUSIONS: This provides both a guide for users what is important and recommendations for existing and upcoming sRNA target prediction approaches.We show on a large sRNA target screen benchmark data set that only by altering the parameter set, IntaRNA recovers 30% more verified interactions while becoming 5-times faster. This exemplifies the potential of seed, accessibility and interaction constraints for sRNA target prediction.


Asunto(s)
Bacterias/genética , Biología Computacional/métodos , ARN Bacteriano/genética , ARN Pequeño no Traducido/genética , Bacterias/química , Bacterias/metabolismo , ARN Bacteriano/química , ARN Bacteriano/metabolismo , ARN Pequeño no Traducido/química , ARN Pequeño no Traducido/metabolismo
14.
Chemosphere ; 243: 125434, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31995884

RESUMEN

In this study, the granular sludge was operated under low aeration condition in sequencing batch reactor (SBR) and advanced continuous flow reactor (ACFR), respectively. Through increasing the sludge retention time (SRT) from 22 days to 33 days, the ACFR was successful startup in 30 days and achieved long term stable operation. Under SBR operation condition, the aerobic granular sludge (AGS) showed good nitrogen (60%), phosphorus (96%) and COD removal performance. During stable operation of continuous-flow, the nitrogen removal efficiency was increasing to 70%, however, the phosphorus removal efficiency could only be restored to 65%. Meanwhile, the sludge discharge volume from ACFR was about half of that in SBR. Results of high-throughput pyrosequencing illustrated that methanogenic archaea (MA), ammonia oxidizing archaea (AOA), denitrifying bacteria (DNB), denitrifying polyphosphate-accumulating organisms (DPAOs) played an important role in the removal of nutrients in ACFR. This study could have positive effect on the practical application of AGS continuous flow process for simultaneous biological nutrient removal (SBNR).


Asunto(s)
Aerobiosis , Desnitrificación , Microbiota , Aguas del Alcantarillado/microbiología , Archaea/metabolismo , Bacterias/metabolismo , Reactores Biológicos/microbiología , Nitrógeno/aislamiento & purificación , Fósforo/aislamiento & purificación , Polifosfatos
15.
World J Microbiol Biotechnol ; 36(2): 19, 2020 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-31955250

RESUMEN

Microbial fuel cells (MFCs) have emerged as a promising technology for sustainable wastewater treatment coupled with electricity generation. A MFC is a device that uses microbes as catalysts to convert chemical energy present in biomass into electrical energy. Among the various mechanisms that drive the operation of a MFC, extracellular electron transfer (EET) to the anode is one of the most important. Exoelectrogenic bacteria can natively transfer electrons to a conducting surface like the anode. The mechanisms employed for electron transfer can either be direct transfer via conductive pili or nanowires, or mediated transfer that involves either naturally secreted redox mediators like flavins and pyocyanins or artificially added mediators like methylene blue and neutral red. EET is a mechanism wherein microorganisms extract energy for growth and maintenance from their surroundings and transfer the resulting electrons to the anode to generate current. The efficiency of these electron transfer mechanisms is dependent not only on the redox potentials of the species involved, but also on microbial oxidative metabolism that liberates electrons. Attempts at understanding the electron transfer mechanisms will boost efforts in giving rise to practical applications. This article covers the various electron transfer mechanisms involved between microbes and electrodes in microbial fuel cells and their applications.


Asunto(s)
Fuentes de Energía Bioeléctrica/microbiología , Aguas Residuales/análisis , Bacterias/metabolismo , Transporte de Electrón , Oxidación-Reducción , Propiedades de Superficie
16.
World J Microbiol Biotechnol ; 36(2): 21, 2020 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-31955272

RESUMEN

Ampicillin is a widely used ß-lactam antibiotic that has been detected in various effluents and can alter biological processes used in wastewater treatment such as nitrification. Physiological and kinetic behaviour of a nitrifying consortium in the presence of ampicillin (AMP) (10, 25, and 50 mg/L) was evaluated in batch cultures. Under the experimental conditions (320 ± 8 mg bacterial protein/L, C/N = 2.4, 24 h), the nitrifying behaviour was very similar among the controls without AMP and the assays with antibiotic, as there was no AMP effect on efficiency (ENH4+ = 99.7 ± 4.2%), yields (YNO2- = 0, YNO3- = 1.0 ± 0.1 mg N/mg NH4+-N consumed), neither specific rates of NH4+ oxidation and NO3- formation. Therefore, nitrifying bacteria were insensitive to AMP presence. At all assayed concentrations, after 24 h, 70.5 ± 3.7% of AMP was removed from the cultures through abiotic (16.0-16.5%), biosorption (23.2-47.0%), and biotransformation (10.0-29.8%) processes. With the increase in the initial AMP concentration, a greater participation of the biotransformation process, associated to an increase in the specific AMP consumption rate was attained. The sludge was able to completely oxidize NH4+ to NO3- by nitrification and eliminate AMP biologically, but without reaching its full mineralization.


Asunto(s)
Ampicilina/análisis , Bacterias/crecimiento & desarrollo , Técnicas de Cultivo Celular por Lotes/métodos , Compuestos de Amonio/análisis , Bacterias/metabolismo , Biodegradación Ambiental , Reactores Biológicos/microbiología , Biotransformación , Nitrificación
17.
World J Microbiol Biotechnol ; 36(2): 26, 2020 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-31997078

RESUMEN

Salinity stress is one of the key constraints for sustainable crop production. It has gained immense importance in the backdrop of climate change induced imbalanced terrestrial water budgets. The traditional agronomic approaches and breeding salt-tolerant genotypes have often proved insufficient to alleviate salinity stress. Newer approaches like the use of bacterial endophytes associated with agricultural crops have occupied center place recently, owing to their advantageous role in improving crop growth, health and yield. Research evidences have revealed that bacterial endophytes can promote plant growth by accelerating availability of mineral nutrients, helping in production of phytohormones, siderophores, and enzymes, and also by activating systemic resistance against insect pest and pathogens in plants. These research developments have opened an innovative boulevard in agriculture for capitalizing bacterial endophytes, single species or consortium, to enhance plant salt tolerance capabilities, and ultimately lead to translational refinement of crop-production business under salty environments. This article reviews the latest research progress on the identification and functional characterization of salt tolerant endophytic bacteria and illustrates various mechanisms triggered by them for plant growth promotion under saline environment.


Asunto(s)
Bacterias/metabolismo , Endófitos/fisiología , Desarrollo de la Planta/fisiología , Tolerancia a la Sal/fisiología , Plantas Tolerantes a la Sal/microbiología , Productos Agrícolas/metabolismo , Productos Agrícolas/microbiología , Microbiota , Reguladores del Crecimiento de las Plantas/metabolismo , Raíces de Plantas/microbiología , Salinidad , Sideróforos/metabolismo , Microbiología del Suelo
18.
J Agric Food Chem ; 68(4): 1091-1100, 2020 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-31896257

RESUMEN

The physical structure of type 1 resistant starch (RS 1) could influence the metabolite production and stimulate the growth of specific bacteria in the human colon. In the present study, we isolated intact cotyledon cells from pinto bean seeds as whole pulse food and RS 1 model and obtained a series of cell wall integrities through controlled enzymolysis. In vitro human fecal fermentation performance and microbiota responses were tested, and we reported that the cell wall integrity controls the in vitro fecal fermentation rate of heat-treated pinto bean cells. The concentration of butyrate produced by pinto bean cell fermentation enhanced with weakened cell wall integrity, and certain beneficial bacterial groups such as Blautia and Roseburia genera were remarkably promoted by pinto bean cells with damaged cell wall integrity. However, the intact cell sample had a shape more similar to microbiota composition with the purified cell wall polysaccharides, rather than the damaged cells.


Asunto(s)
Bacterias/metabolismo , Pared Celular/metabolismo , Heces/microbiología , Microbioma Gastrointestinal , Phaseolus/metabolismo , Bacterias/química , Bacterias/clasificación , Bacterias/aislamiento & purificación , Pared Celular/química , Fermentación , Humanos , Phaseolus/química , Polisacáridos/metabolismo , Semillas/química , Semillas/metabolismo
19.
J Agric Food Chem ; 68(6): 1634-1644, 2020 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-31961687

RESUMEN

A novel microbial consortium (NZDC-6) was screened and characterized to detoxify the estrogenic mycotoxin zearalenone (ZEA), which commonly contaminates maize and is a major threat to food and health security. We found NZDC-6 to be thermophilic and highly effective, with a 90.3% ZEA degradation ratio at an optimum temperature of 60 °C. NZDC-6 was also effective at degrading the more estrogenic ZEA cognates, α-zearalenol (α-ZAL) and ß-zearalenol (ß-ZAL), with >90% degradation ratios. To evaluate a practical application, ZEA-contaminated corncobs were treated with NZDC-6 via semisolid fermentation. Measurements of physicochemical parameters and 16S microbial diversity and redundancy analysis (RDA) indicated that ZEA removal was most efficient at a low corncob solid content (< 5%), as a high solid content overwhelmed the microbial metabolic load, leading to increased dissolved oxygen and lowered pH. Our results demonstrate that the control of environmental variables is crucial for effective ZEA microbial removal in practical applications.


Asunto(s)
Bacterias/metabolismo , Consorcios Microbianos , Zea mays/microbiología , Zearalenona/metabolismo , Bacterias/genética , Bacterias/crecimiento & desarrollo , Bacterias/aislamiento & purificación , Biodegradación Ambiental , Fermentación , Contaminación de Alimentos/análisis
20.
Appl Microbiol Biotechnol ; 104(5): 1883-1890, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31932892

RESUMEN

C-Glycosides, a special type of glycoside, are frequently distributed in many kinds of medicinal plants, such as puerarin and mangiferin, showing various and significant bioactivities. C-Glycosides are usually characterized by the C-C bond that forms between the anomeric carbon of sugar moieties and the carbon atom of aglycon, which is usually resistant against acidic hydrolysis and enzymatic treatments. Interestingly, C-glycosides could be cleaved by several intestinal bacteria, but whether the enzymatic cleavage of C-C glycosidic bond is reduction or hydrolysis has been controversial; furthermore, whether existence of a "C-glycosidase" directly catalyzing the cleavage is not clear. Here we review research advances about the discovery and mechanism of intestinal bacteria in enzymatic cleavage of C-C glycosidic bond with an emphasis on the identification of enzymes manipulation the deglycosylation. Finally, we give a brief conclusion about the mechanism of C-glycoside deglycosylation and perspectives for future study in this field.


Asunto(s)
Bacterias/enzimología , Bacterias/metabolismo , Proteínas Bacterianas/metabolismo , Glicósido Hidrolasas/metabolismo , Glicósidos/metabolismo , Intestinos/microbiología , Animales , Bacterias/aislamiento & purificación , Proteínas Bacterianas/genética , Biotransformación , Glicósido Hidrolasas/genética , Glicósidos/química , Glicosilación , Humanos , Estructura Molecular
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