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1.
Bioresour Technol ; 333: 125082, 2021 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-33878502

RESUMEN

High concentrations of nitrous oxide were recovered from partial nitrification treated leachate in a microbial electrolysis cell (MEC) inoculated with a nosZ-deficient strain of Pseudomonas aeruginosa. N2O conversion efficiencies > 90% were achieved when a potential of 0.8 V was applied to the MEC. The ΔnosZ strain was enriched in the 0.8 V MEC, but Achromobacter dominated the non-current control. Nitric oxide reductase genes were highly expressed by ΔnosZ cells growing in the 0.8 V MEC, consistent with enhanced nitrous oxide production rates. Concentrations of phenazine derivatives and transcripts from phenazine biosynthesis genes were also high in the 0.8 V MEC. Phenazine derivatives are known to act as electron shuttles, enhance biofilm formation, and help ward off competitors, thereby increasing the survivability of the ΔnosZ strain in the MEC. These results show that applied current stabilized growth of the ΔnosZ strain in the reactor and allowed it to sustainably generate high concentrations of nitrous oxide.

2.
Artículo en Inglés | MEDLINE | ID: mdl-33864544

RESUMEN

A novel Gram-negative, rod-shaped, aerobic, oxidase-positive and catalase-negative bacterium, designated strain SM1970T, was isolated from a seawater sample collected from the Mariana Trench. Strain SM1970T grew at 15-37 oC and with 1-5% (w/v) NaCl. It hydrolyzed colloidal chitin, agar and casein but did not reduce nitrate to nitrite. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain SM1970T formed a distinct lineage close to the genus Catenovulum within the family Alteromonadaceae, sharing the highest sequence similarity (93.6%) with type strain of Catenovulum maritimum but < 93.0% sequence similarity with those of other known species in the class Gammaproteobacteria. The major fatty acids of strain SM1970T were summed feature 3 (C16: 1 ω7c and/or C16: 1 ω6c), C16: 0 and summed feature 8 (C18: 1 ω7c and/or C18: 1 ω6c). The major polar lipids of the strain included phosphatidylethanolamine and phosphatidylglycerol and its main respiratory quinone was ubiquinone 8. The draft genome of strain SM1970T consisted of 77 scaffolds and was 4,172,146 bp in length, containing a complete set of genes for chitin degradation. The average amino acid identity (AAI) values between SM1970T and type strains of known Catenovulum species were 56.6-57.1% while the percentage of conserved proteins (POCP) values between them were 28.5-31.5%. The genomic DNA G + C content of strain SM1970T was 40.1 mol%. On the basis of the polyphasic analysis, strain SM1970T is considered to represent a novel species in a novel genus of the family Alteromonadaceae, for which the name Marinifaba aquimaris is proposed with the type strain being SM1970T (= MCCC 1K04323T = KCTC 72844T).

3.
BMC Pregnancy Childbirth ; 21(1): 179, 2021 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-33663421

RESUMEN

BACKGROUND: Breastfeeding plays an important role in the early stages of humans and throughout the development process. Breastfeeding competency is a self-assessment of pregnant women's overall competency to breastfeeding which could predict the breastfeeding behaviours of pregnant women. However, a valid and reliable scale for assessing breastfeeding competency has not yet been developed and validated. This study was conducted to develop and validate an assessment scale designed to assess pregnant women's breastfeeding competency in the third trimester: the Breastfeeding Competency Scale (BCS). METHODS: The BCS was developed and validated over three phases between September 2018 and September 2019, and these phases included item statistical analysis, exploratory factor analysis (EFA), content validation, internal consistency assessment, split-half reliability assessment and confirmatory factor analysis (CFA). RESULTS: The item statistical analysis and EFA resulted in 38 items and 4 factors that explained 66.489% of the total variance. The Cronbach's α coefficients for the total scale and the 4 factors were 0.970, 0.960, 0.940, 0.822 and 0.931. The split-half reliability of the BCS was 0.894 and 0.890. CFA model showed that the 4-factor model fits the data well. CONCLUSIONS: The BCS is a new valid and reliable instrument for assessing the breastfeeding competency of pregnant women in the third trimester.

4.
Bioresour Technol ; 330: 124965, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33735725

RESUMEN

With the increasing of data in wastewater treatment, data-driven machine learning models are useful for modeling biological processes and complex reactions. However, few data-driven models have been developed for simulating the microbial electrolysis cells (MECs) and traditional models are too ambiguous to comprehend the mechanisms. In this study, a new general data-driven two-stage model was firstly developed to predict CH4 production from in-situ biogas upgrading in the biocathode MECs via direct electron transfer (DET), named NARX-BP hybrid neural networks. Compared with traditional one-stage model, the model could well predict methane production via DET with excellent performance (all R2 and MES of 0.918 and 6.52 × 10-2, respectively) and reveal the mechanisms of biogas upgrading, for the new systematical modeling approach could improve the versatility and applicability by inputting significant intermediate variables. In addition, the model is generally available to support long-term prediction and optimal operation for anaerobic digestion or complex MEC systems.


Asunto(s)
Biocombustibles , Metano , Anaerobiosis , Reactores Biológicos , Electrólisis , Electrones , Aprendizaje Automático , Redes Neurales de la Computación
5.
Water Res ; 197: 117055, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33789202

RESUMEN

Biogas produced from anaerobic digestion usually contains 30%-50% CO2, much of which must be removed, before utilization. Bioelectrochemical biogas upgrading approaches show promise, however, they have not yet been optimized for practical applications. In this study, a bioelectrochemical system with low energy input (applied cathode potential of -0.5 V vs. standard hydrogen electrode, SHE) was used for in-situ biogas upgrading. High efficiency CO2 conversion (318.5 mol/d/m2) was achieved when the system was operated with an organic load of 1.7 kgCOD/(m3 d). Methane content in the upgraded biogas was 97.0% and CO2 concentrations stayed below 3%, which is comparable to biogas upgraded with more expensive and less sustainable physiochemical approaches. The high efficiency of this approach could likely be attributed to a significant enrichment of Methanothrix (92.7%) species on the cathode surface that were expressing genes involved in both acetogenic methanogenesis and direct electron transfer (DET). Electromethanogenesis by these organisms also increased proton consumption and created a higher pH that increased the solubility of CO2 in the bioreactor. In addition, CO2 removal from the biogas was likely further enhanced by an enrichment of Actinobacillus species known to be capable of CO2 fixation. Artificial neural network (ANN) models were also used to estimate CH4 production under different loading conditions. The ANN architecture with 10 neurons at hidden layers fit best with a mean square error of 6.06 × 10-3 and R2 of 0.99.


Asunto(s)
Biocombustibles , Metano , Reactores Biológicos , Dióxido de Carbono , Electrodos , Methanosarcinaceae
6.
Environ Microbiol ; 2020 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-33185972

RESUMEN

Most marine copiotrophic bacteria can produce extracellular enzymes to degrade biopolymers into bio-available smaller solutes, while oligotrophic bacteria usually cannot. Bacterial extracellular enzymes and enzymatic products can be a common resource that could be utilized by both copiotrophs and oligotrophs; when present, oligotrophs may outcompete the enzyme-producing copiotrophs. However, copiotrophs and oligotrophs consistently coexist in the ocean. How they maintain coexistence has still not been experimentally studied. In this study, the interaction and coexistence of a copiotroph and an oligotroph, isolated from the same surface seawater sample and utilizing the same proteinaceous substrate, were experimentally investigated. The copiotroph could secrete extracellular proteases to degrade and then utilize the proteinaceous substrate. The oligotroph was unable to utilize the proteinaceous substrate by itself, but could grow by using the hydrolysate amino acids. The copiotroph outcompeted the oligotroph by adsorbing the amino acids quickly and having a higher growth rate in the rich medium. The oligotroph survived by adapting to low concentration of nutrients. The copiotroph and oligotroph were able to maintain long-term (up to 142 days) coexistence in the laboratory. This study indicates that differences in the utilization of different concentrations of nutrients can drive the coexistence of marine copiotrophs and oligotrophs.

7.
Environ Sci Technol ; 54(19): 12539-12549, 2020 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-32897064

RESUMEN

The formation of vivianite (Fe3(PO4)2·8H2O) in iron (Fe)-dosed wastewater treatment facilities has the potential to develop into an economically feasible method of phosphorus (P) recovery. In this work, a long-term steady FeIII-dosed University of Cape Town process-membrane bioreactor (UCT-MBR) system was investigated to evaluate the role of Fe transformations in immobilizing P via vivianite crystallization. The highest fraction of FeII, to total Fe (Fetot), was observed in the anaerobic chamber, revealing that a redox condition suitable for FeIII reduction was established by improving operational and configurational conditions. The supersaturation index for vivianite in the anaerobic chamber varied but averaged ∼4, which is within the metastable zone and appropriate for its crystallization. Vivianite accounted for over 50% of the Fetot in the anaerobic chamber, and its oxidation as it passed through the aerobic chambers was slow, even in the presence of high dissolved oxygen concentrations at circumneutral pH. This study has shown that the high stability and growth of vivianite crystals in oxygenated activated sludge can allow for the subsequent separation of vivianite as a P recovery product.

8.
Clin Chim Acta ; 510: 613-616, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32858058

RESUMEN

BACKGROUND: Qualitative and quantitative detection of nucleic acids of SARS-CoV-2, the pathogen that causes coronavirus disease 2019 (COVID-19), plays a significant role in COVID-19 diagnosis, surveillance, prevention, and control. METHODS: A total of 117 samples from 30 patients with confirmed COVID-19 and 61 patients without COVID-19 were collected. Reverse transcriptase quantitative PCR (RT-qPCR) and droplet digital PCR (ddPCR) were used for qualitative and quantitative analyses of these samples to evaluate the diagnostic performance and applicability of the two methods. RESULTS: The positive detection rates of RT-qPCR and ddPCR were 93.3% and 100%, respectively. Among the 117 samples, 6 samples were tested single-gene positive by RT-qPCR but positive by ddPCR, and 3 samples were tested negative by RT-qPCR but positive by ddPCR. The viral load of samples with inconsistent results were relatively low (3.1-20.5 copies/test). There were 17 samples (37%) with a viral load below 20 copies/test among the 46 positive samples, and only 9 of them were successfully detected by RT-qPCR. A severe patient was dynamically monitored. All 6 samples from this patient were tested negative by RT-qPCR, but 4 samples were tested positive by ddPCR with a low viral load. CONCLUSION: Qualitative analysis of COVID-19 samples can meet the needs of clinical screening and diagnosis, while quantitative analysis provides more information to the research community. Although both ddPCR and RT-qPCR can provide qualitative and quantitative results, ddPCR showed higher sensitivity and lower limit of detection than RT-qPCR, and it does not rely on the standard curve to quantify viral load. Therefore, ddPCR offers greater advantages than RT-qPCR.


Asunto(s)
Infecciones por Coronavirus/diagnóstico , Neumonía Viral/diagnóstico , Adulto , Anciano , Estudios de Casos y Controles , Infecciones por Coronavirus/genética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pandemias , Neumonía Viral/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sensibilidad y Especificidad , Carga Viral
9.
Environ Res ; 189: 109884, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32678736

RESUMEN

Biological treatment of high salinity organic wastewater is a significant challenge because many microorganisms involved in the anaerobic digestion process cannot survive high osmotic pressures. In order to alleviate some of the stresses associated with the treatment of high salinity wastewater, two lab-scale up-flow anaerobic sludge bed reactors with or without magnetite (100 g/L) were used to treat high salinity organic wastewater. This study showed that the bioreactor amended with magnetite had higher chemical oxygen demand removal efficiencies (90.2% ± 0.54% vs 73.1% ± 1.9%) and methane production rates (4082 ± 334 ml (standard temperature and atmospheric pressure, STP)/d vs 2640 ± 120 ml (STP)/d) than the non-amended control reactor. In addition, the consumption of volatile fatty acids (20.9 ± 3.4 mM vs 61.7 ± 2.0 mM) was accelerated. Microbial community analysis revealed that the addition of magnetite caused the enrichment of many bacterial genera known to form robust biofilms (i.e. Pseudomonas) that are also capable of extracellular electron transfer and methanogens from the genus Methanosarcina which have been shown to participate in direct interspecies electron transfer. These results show that magnetite addition could enhance the performance of anaerobic digesters treating high salinity wastewater.

10.
Asia Pac J Clin Nutr ; 29(1): 83-93, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32229446

RESUMEN

BACKGROUND AND OBJECTIVES: Multiple studies of the relative economic value of different nutritional support methods for patients with gastrointestinal cancer have provided inconsistent results. METHODS AND STUDY DESIGN: The PUBMED and EMBASE databases were systematically searched through September 30, 2018to identify latent studies of the benefits of parenteral nutrition (PN), enteral nutrition (EN) or conventional intervention (CI) in gastrointestinal cancer patients. A fixed-effects model or random-effects model was applied depending on the heterogeneity of the studies. Statistical analysis was conducted using R software. A total of 728 studies were reviewed, and 21 studies published from 1998 to 2018 were included in the final analysis. RESULTS: The results showed that the hospitalization expenditure of the EN group was 3938 RMB less than that of the PN group. Similarly, the EN group had a shorter length of hospitalization than the PN and CI groups. The infection rate was lower in the EN group (12%) than in the PN group (16%) and CI group (20%). Subgroup analysis showed that gastrointestinal cancer patients who received oral nutritional supplements had the lowest infection rate (11%) after surgery. CONCLUSIONS: EN, especially oral nutritional supplements, has a positive economic impact on patients with gastrointestinal cancer, based on reductions in the post-operative infection rate, length of hospitalization, and hospitalization expenditure.

11.
Bioresour Technol ; 297: 122422, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31767427

RESUMEN

In order to illustrate the impact that application of positive or negative potential to conductive materials can have on direct interspecies electron transfer (DIET) and reactor performance under high organic loading rates, three continuous laboratory-scale reactors with carbon-cloth electrodes poised at +0.7 V, -0.7 V (vs. Ag/AgCl) and no-potential were fed high concentrations of ethanol wastewater. While exoelectrogens and methanogens that are capable of DIET were significantly enriched in poised reactors, they performed worse than the non-current control. Volatile fatty acids (VFAs) accumulated more rapidly in the positively then negatively poised reactor, but neither could withstand high-loading rates. These results demonstrate that applying potential to conductive materials had a negative effect on anaerobic digestion under high-loading conditions.


Asunto(s)
Reactores Biológicos , Metano , Anaerobiosis , Transporte de Electrón , Electrones
12.
Bioresour Technol ; 297: 122371, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31753601

RESUMEN

In this study, nitrous oxide was recovered from a lab-scale moving-bed biofilm reactor (MBBR) treating partial nitrification-treated leachate supplemented with a nosZ-deficient strain of Pseudomonas aeruginosa. Batch culture tests with the nosZ-deficient strain determined that the threshold for free nitrous acid (FNA) inhibition was 0.016 mg/L and that FNA concentrations above this threshold severely inhibited denitrification and transcription of genes from the dissimilatory nitrate reduction pathway (narG, nirS, and norB). High nitrite removal and N2O conversion efficiencies (>95%) were achieved with long-term operation of this MBBR. N2O accounted for the majority of biogas (80%) produced when the MBBR was fed partial nitrification-treated leachate with high nitrite concentrations and the drainage ratio was adjusted to 30%. Bacterial community analysis revealed that the nosZ-deficient Pseudomonas strain remained metabolically active and was primarily responsible for denitrification processes in the reactor. This study presents a promising method for N2O recovery from incineration leachate.


Asunto(s)
Óxido Nitroso , Pseudomonas aeruginosa , Biopelículas , Reactores Biológicos , Desnitrificación , Incineración
13.
Int J Syst Evol Microbiol ; 70(1): 105-111, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31626585

RESUMEN

A Gram-negative, aerobic, non-flagellated and ovoid- or rod-shaped bacterium, designated strain SM1902T, was isolated from the sediment sampled at the Jia River estuary, Yantai, PR China. The strain grew at 10-37 °C (optimum, 25-30 °C), pH 6.0-10.0 (pH 7.0) and with 0.5-13.0 % (w/v) NaCl (2.5%). It reduced nitrate to nitrite, but did not produce bacteriochlorophyll a. The results of phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1902T constituted a separated lineage within the family Rhodobacteraceae and was closely related to Meridianimarinicoccus roseus TG-679T and Phycocomes zhengii LMIT002T with 96.1 and 94.3 % 16S rRNA gene sequence similarities, respectively. The predominant cellular fatty acid was summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, an unidentified aminolipid and an unidentified lipid. The sole respiratory quinone was ubiquinone-10. The in silico DNA-DNA hybridization values between strain SM1902T and Meridianimarinicoccus roseus TG-679T and Phycocomes zhengii LMIT002T were 19.6 and 19.5 %, respectively; and the average nucleotide identity values between them were 76.1 and 74.2 %, respectively. The genomic DNA G+C content of strain SM1902T was 58.2 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic data obtained in this study, strain SM1902T is considered to represent a novel species in a new genus within the family Rhodobacteraceae, for which the name Fluviibacterium aquatile gen. nov., sp. nov. is proposed. The type strain is SM1902T (=KCTC 72045T=MCCC 1K03596T=CCTCC AB 2018346T).


Asunto(s)
Estuarios , Sedimentos Geológicos/microbiología , Filogenia , Rhodobacteraceae/clasificación , Técnicas de Tipificación Bacteriana , Bacterioclorofila A , Composición de Base , China , ADN Bacteriano/genética , Ácidos Grasos/química , Hibridación de Ácido Nucleico , Fosfolípidos/química , ARN Ribosómico 16S/genética , Rhodobacteraceae/aislamiento & purificación , Agua de Mar/microbiología , Análisis de Secuencia de ADN , Ubiquinona/análogos & derivados , Ubiquinona/química
14.
Bioresour Technol ; 298: 122547, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31837579

RESUMEN

Anaerobic dynamic membrane bioreactors (AnDMBRs) can improve the efficiency of organic matter removal during wastewater treatment at a low cost. However, application of AnDMBRs for treatment of high-strength wastewater is usually unsuccessful. This study investigated whether use of conductive carbon cloth as the supporting material in an AnDMBR permits higher organic loading rates for treatment of brewery wastewater than non-conductive polyester cloth. The AnDMBR with carbon cloth operated stably with a COD removal efficiency of 98% even when high concentrations of influent COD (10,000 mg/L) were provided, while the polyester cloth reactor deteriorated when reactors were fed only 5000 mg/L influent COD. Microorganisms capable of direct interspecies electron transfer (DIET), including Geobacter and Methanothrix species, dominated the surface of the carbon cloth. These results demonstrate that carbon cloth provides an excellent supporting material for AnDMBRs by stimulating growth of microorganisms that can directly transport electrons to and from conductive materials.


Asunto(s)
Carbono , Aguas Residuales , Anaerobiosis , Reactores Biológicos , Textiles , Eliminación de Residuos Líquidos
15.
Front Microbiol ; 10: 2408, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31681251

RESUMEN

Antarctica is covered by multiple larger glaciers with diverse extreme conditions. Microorganisms in Antarctic regions are primarily responsible for diverse biogeochemical processes. The identity and functionality of microorganisms from polar glaciers are defined. However, little is known about microbial communities from the high elevation glaciers. The Union Glacier, located in the inland of West Antarctica at 79°S, is a challenging environment for life to survive due to the high irradiance and low temperatures. Here, soil and rock samples were obtained from three high mountains (Rossman Cove, Charles Peak, and Elephant Head) adjacent to the Union Glacier. Using metagenomic analyses, the functional microbial ecosystem was analyzed through the reconstruction of carbon, nitrogen and sulfur metabolic pathways. A low biomass but diverse microbial community was found. Although archaea were detected, bacteria were dominant. Taxa responsible for carbon fixation were comprised of photoautotrophs (Cyanobacteria) and chemoautotrophs (mainly Alphaproteobacterial clades: Bradyrhizobium, Sphingopyxis, and Nitrobacter). The main nitrogen fixation taxa were Halothece (Cyanobacteria), Methyloversatilis, and Leptothrix (Betaproteobacteria). Diverse sulfide-oxidizing and sulfate-reducing bacteria, fermenters, denitrifying microbes, methanogens, and methane oxidizers were also found. Putative producers provide organic carbon and nitrogen for the growth of other heterotrophic microbes. In the biogeochemical pathways, assimilation and mineralization of organic compounds were the dominant processes. Besides, a range of metabolic pathways and genes related to high irradiance, low temperature and other stress adaptations were detected, which indicate that the microbial communities had adapted to and could survive in this harsh environment. These results provide a detailed perspective of the microbial functional ecology of the Union Glacier area and improve our understanding of linkages between microbial communities and biogeochemical cycling in high Antarctic ecosystems.

16.
Bioresour Technol ; 291: 121877, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31376672

RESUMEN

Bioelectrochemical conversion of CO2 to CH4 is a promising way to increase the calorific value of biogas produced during anaerobic digestion. There are two groups of methanogens enriched in these systems, hydrogenotrophs and acetoclastic methanogens that can also directly accept electrons from an electrode or another microorganism. In this study, a microbial electrolysis cell (MEC) poised at -500 mV (vs. SHE) was operated for biogas upgrading. Methane content in the biogas increased from 71% to >90%, and 8.2% of the CO2 was converted to methane. Methanothrix, an acetoclastic methanogen that can participate in direct electron transfer (DET), and Azonexus, an acetate-oxidizing electrogen, were enriched on the cathode. Transcriptomics revealed that Methanothrix on the cathode were using the CO2 reduction pathway, while Methanothrix in the bulk sludge were using the acetate decarboxylation pathway for production of methane. These results show that stimulation of DET in MEC enhances biogas-upgrading processes.


Asunto(s)
Biocombustibles , Methanosarcinaceae , Electrodos , Electrólisis , Transporte de Electrón , Electrones , Metano/metabolismo , Aguas del Alcantarillado
17.
Int J Syst Evol Microbiol ; 69(8): 2571-2576, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31225791

RESUMEN

A Gram-stain-negative, aerobic, flagellated, rod-shaped bacterial strain, SM1705T, was isolated from a surface seawater sample collected from the South China Sea. The strain grew at 10-40 °C and with 0.5-13.0 % (w/v) NaCl. It hydrolysed Tweens 20, 40 and 60, but did not hydrolyse starch or Tween 80 nor reduce nitrate to nitrite. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1705T was affiliated with the genus Parvularcula, sharing the highest sequence similarity (96.0 %) with type strain of Parvularcula bermudensis and forming a coherent branch together with the latter within the clade of Parvularcula. The major cellular fatty acids were identified as summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0 and C18 : 0. Polar lipids included three unidentified glycolipids and one unidentified lipid. The major respiratory quinone of strain SM1705T was Q10. The genomic DNA G+C content of strain SM1705T was 59.3 mol%. Based on the polyphasic evidence presented in this paper, strain SM1705T represents a novel Parvularcula species, for which the name Parvularcula marina sp. nov. is proposed. The type strain is SM1705T (=KCTC 62795T=MCCC 1K03505T=CCTCC AB 2018345T).


Asunto(s)
Alphaproteobacteria/clasificación , Filogenia , Agua de Mar/microbiología , Alphaproteobacteria/aislamiento & purificación , Técnicas de Tipificación Bacteriana , Composición de Base , China , ADN Bacteriano/genética , Ácidos Grasos/química , Glucolípidos/química , Fosfolípidos/química , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Ubiquinona/análogos & derivados , Ubiquinona/química
18.
Environ Sci Technol ; 53(15): 9045-9053, 2019 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-31251600

RESUMEN

By mimicking iron(Fe)-based phosphorus (P) immobilization in natural environments, an Fe-retrofitted UCT-MBR involving in situ vivianite crystallization for removing and recovering P from sewage was developed, and its performance was examined in this work. We show that dosing of ferrihydrite, once biological P uptake reached its limit, enabled effective ongoing P removal; whereas conventional conditions in the anaerobic chamber of the University of Cape Town (UCT) system (i.e., a sludge retention time of hours and a completely mixed sludge phase) was insufficient for a satisfactory Fe(III) bioreduction, with the overaccumulation of Fe(III) as fine particles finally resulting in severe membrane fouling and collapse in P removal. The enhancement of reductive conditions in the anaerobic chamber by lowering agitation and adding biocarriers to favor Fe(III) reduction was found to be effective in enabling ongoing P removal and recovery. The average level of effluent P was as low as 0.18 mg/L for a period of 258 d under this condition. Using chemical and spectroscopic methods, the P product was identified as primarily vivianite: Fe3(PO4)2·8H2O. The in situ crystallization of vivianite as a sink for P enabled the UCT-MBR to continuously remove and recover sewage P with no need for sludge discharge.


Asunto(s)
Fósforo , Aguas del Alcantarillado , Reactores Biológicos , Cristalización , Compuestos Férricos , Compuestos Ferrosos , Fosfatos , Eliminación de Residuos Líquidos
19.
Water Res ; 161: 570-580, 2019 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-31238222

RESUMEN

The raw fresh leachate from municipal solid waste (MSW) incineration plants contains high concentrations of volatile fatty acids (VFAs), ammonia and metals, all compounds that severely limit anaerobic digestion treatment efficiencies. These inhibitory compounds make reactor systems unstable, causing reactor start-up periods to take more than 100 days, even when the leachate is diluted significantly. In this study, granular activated carbon (GAC) was incorporated into a bioreactor fed with raw incineration leachate. Addition of GAC allowed direct treatment of raw incineration leachate without any start-up acclimation period, while the non-amended control reactor soured immediately and collapsed within 17 days. When hydraulic retention time (HRT) of the GAC-amended reactor was stepwise decreased to increase organic loading rates (OLR) to 25.0 kgCOD/(m3·d), COD removal efficiencies remained stable at >90%. Metagenomic analysis of the GAC-amended reactor revealed that Geobacter and Methanosarcina, species known to participate in direct interspecies electron transfer (DIET), were more abundant in the GAC-amended reactor than the seed sludge. In addition, the abundance of genes coding for proteins thought to be involved in DIET such as electrically conductive pili and the outer membrane c-type cytochrome, OmcS, increased significantly, while genes involved in fermentation, and nitrate (narG) and sulfate (dsrA) reduction dropped significantly as the experiment progressed. These results are significant because this is the first detailed investigation into the metabolic capabilities of microbial communities involved in efficient treatment of raw incineration leachate within biomethanogenic reactors that did not require a long start-up period.


Asunto(s)
Carbón Orgánico , Incineración , Anaerobiosis , Reactores Biológicos , Electrones , Metano , Aguas del Alcantarillado
20.
World J Gastroenterol ; 25(23): 2863-2877, 2019 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-31249445

RESUMEN

Molecular mechanisms associated with inflammation-promoted tumorigenesis have become an important topic in cancer research. Various abnormal epigenetic changes, including DNA methylation, histone modification, chromatin remodeling, and noncoding RNA regulation, occur during the transformation of chronic inflammation into colorectal cancer (CRC). These changes not only accelerate transformation but also lead to cancer progression and metastasis by activating carcinogenic signaling pathways. The NF-κB and STAT3 signaling pathways play a particularly important role in the transformation of inflammation into CRC, and both are critical to cellular signal transduction and constantly activated in cancer by various abnormal changes including epigenetics. The NF-κB and STAT3 signals contribute to the microenvironment for tumorigenesis through secretion of a large number of pro-inflammatory cytokines and their crosstalk in the nucleus makes it even more difficult to treat CRC. Compared with gene mutation that is irreversible, epigenetic inheritance is reversible or can be altered by the intervention. Therefore, understanding the role of epigenetic inheritance in the inflammation-cancer transformation may elucidate the pathogenesis of CRC and promote the development of innovative drugs targeting transformation to prevent and treat this malignancy. This review summarizes the literature on the roles of epigenetic mechanisms in the occurrence and development of inflammation-induced CRC. Exploring the role of epigenetics in the transformation of inflammation into CRC may help stimulate futures studies on the role of molecular therapy in CRC.


Asunto(s)
Transformación Celular Neoplásica/genética , Neoplasias Colorrectales/genética , Epigénesis Genética/inmunología , Regulación Neoplásica de la Expresión Génica/inmunología , Inflamación/genética , Colon/inmunología , Colon/patología , Neoplasias Colorrectales/inmunología , Neoplasias Colorrectales/patología , Progresión de la Enfermedad , Humanos , Inflamación/inmunología , Inflamación/patología , Mucosa Intestinal/inmunología , Mucosa Intestinal/patología , Recto/inmunología , Recto/patología , Microambiente Tumoral/genética , Microambiente Tumoral/inmunología
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