Read by QxMD icon Read


Katarzyna Siegel-Hertz, Véronique Edel-Hermann, Emilie Chapelle, Sébastien Terrat, Jos M Raaijmakers, Christian Steinberg
Disease-suppressive soils are soils in which specific soil-borne plant pathogens cause only limited disease although the pathogen and susceptible host plants are both present. Suppressiveness is in most cases of microbial origin. We conducted a comparative metabarcoding analysis of the taxonomic diversity of fungal and bacterial communities from suppressive and non-suppressive (conducive) soils as regards Fusarium wilts sampled from the Châteaurenard region (France). Bioassays based on Fusarium wilt of flax confirmed that disease incidence was significantly lower in the suppressive soil than in the conducive soil...
2018: Frontiers in Microbiology
Ruiwen Wang, Mei Yan, Huidong Li, Lu Zhang, Benqi Peng, Jinzhi Sun, Da Liu, Shaoqin Liu
Microbial fuel cells (MFCs) have received great attention worldwide due to their potential in recovering electrical energy from waste and inexhaustible biomass. Unfortunately, the difficulty of achieving the high power, especially in real samples, remains a bottleneck for their practical applications. Herein, FeS2 nanoparticles decorated graphene is fabricated via a simple hydrothermal reaction. The FeS2 nanoparticles decorated graphene anode not only benefits bacterial adhesion and enrichment of electrochemically active Geobacter species on the electrode surface but also promotes efficient extracellular electron transfer, thus giving rise to a fast start-up time of 2 d, an unprecedented power density of 3220 mW m-2 and a remarkable current density of 3...
April 17, 2018: Advanced Materials
Changhui Wang, Yu Wu, Leilei Bai, Yaqian Zhao, Zaisheng Yan, Helong Jiang, Xin Liu
This study assesses the feasibility of recycling drinking water treatment residue (DWTR) to treat eutrophic surface water in a one-year continuous flow column test. Heat-treated DWTR was used as an additional medium (2%-4%) in columns in case excessive organic matter and N were released from the DWTR to surface water. The results indicated that with minimal undesirable effects on other water properties, DWTR addition substantially enhanced P removal, rendering P concentrations in treated water oligotrophic and treated water unsuitable for Microcystis aeruginosa breeding...
April 3, 2018: Journal of Environmental Management
Phillipp Sievers, Christopher Moß, Uwe Schröder, Diethelm Johannsmann
Whereas the study of interfaces and thin films with the quartz crystal microbalance (QCM) is well established, biofilms have proven to be a difficult subject for the QCM. The main problem is that the shear wave emanating from the resonator surface does not usually reach to the top of the sample. This problem can be solved with torsional resonators. These have a resonance frequency in the range of tens of kHz, which is much below the frequency of the thickness-shear QCMs. The depth of penetration of the shear wave is correspondingly larger...
March 22, 2018: Biosensors & Bioelectronics
Yue Li, Xiaojing Li, Yang Sun, Xiaodong Zhao, Yongtao Li
The microbial fuel cell (MFC) that uses a solid electrode as the inexhaustible electron acceptor is an innovative remediation technology that simultaneously generates bioelectricity. Chlorinated pollutants are better metabolized by reductive dechlorination in proximity to the cathode. Here, the removal efficiency of the herbicide metolachlor (ML) increased by 262 and 176% in soil MFCs that were spiked with 10 (C10) and 20 mg/kg (C20) of ML, respectively, relative to the non-electrode controls. The bioelectricity output of the C10 and C20 increased by over two- and eightfold, respectively, compared to that of the non-ML control, with maximum current densities of 49...
April 5, 2018: Environmental Science and Pollution Research International
Jin-Ting Wang, Liang Zhang, Yuan Kang, Guanghao Chen, Feng Jiang
This study reported a novel observation that the long-term cultivation of sulfur-reducing bacteria (S0RB) from a sulfate-reducing bacteria (SRB)-abundant seeding sludge with elemental sulfur feeding, significantly shaped the microbial community structure and eliminated the mercury methylation potential in the S0RB-enriched sludge. In this study, the enrichments of SRB and S0RB from activated sludge were obtained through long-term cultivations. Subsequently, the batch tests showed that approximately 5000 μg/L Hg (II) was completely removed from the solution by both the SRB-enriched and S0RB-enriched sludge...
April 4, 2018: Environmental Science & Technology
Nathaniel W Fortney, Shaomei He, Ajinkya Kulkarni, Michael W Friedrich, Charlotte Holz, Eric S Boyd, Eric E Roden
Chocolate Pots hot springs (CP) is a circumneutral pH, Fe-rich geothermal feature located in Yellowstone National Park. Previous Fe(III)-reducing enrichment culture studies with CP sediments identified close relatives of known dissimilatory Fe(III)-reducing bacterial (FeRB) taxa, including Geobacter and Melioribacter However, the abundance and activity of such organisms in the native microbial community is unknown. Here we used stable isotope probing experiments combined with 16S rRNA gene amplicon and shotgun metagenomic sequencing to gain an understanding of the in situ Fe(III)-reducing microbial community at CP...
March 30, 2018: Applied and Environmental Microbiology
Jeong-Hoon Park, Jong-Hun Park, Hoon Je Seong, Woo Jun Sul, Kang-Hyun Jin, Hee-Deung Park
To provide insight into direct interspecies electron transfer via granular activated carbon (GAC), the effect of GAC supplementation on anaerobic digestion was evaluated. Compared to control samples, the GAC supplementation increased the total amount of methane production and its production rate by 31% and 72%, respectively. 16S rDNA sequencing analysis revealed a shift in the archaeal community composition; the Methanosarcina proportion decreased 17%, while the Methanosaeta proportion increased 5.6%. Metagenomic analyses based on shotgun sequencing demonstrated that the abundance of pilA and omcS genes belonging to Geobacter species decreased 69...
March 15, 2018: Bioresource Technology
Oumei Wang, Shiling Zheng, Bingchen Wang, Wenjing Wang, Fanghua Liu
Background: Magnetite-mediated direct interspecies electron transfer (DIET) between Geobacter and Methanosarcina species is increasingly being invoked to explain magnetite stimulation of methane production in anaerobic soils and sediments. Although magnetite-mediated DIET has been documented in defined co-cultures reducing fumarate or nitrate as the electron acceptor, the effects of magnetite have only been inferred in methanogenic systems. Methods: Concentrations of methane and organic acid were analysed with a gas chromatograph and high-performance liquid chromatography, respectively...
2018: PeerJ
Sara Tejedor-Sanz, Patricia Fernández-Labrador, Steven Hart, Cesar I Torres, Abraham Esteve-Núñez
In this study, we designed a microbial electrochemical fluidized bed reactor (ME-FBR), with an electroconductive anodic bed made of activated carbon particles for treating a brewery wastewater. Under a batch operating mode, acetate and propionate consumption rates were 13-fold and 2.4-fold higher, respectively, when the fluidized anode was polarized (0.2 V) with respect to open circuit conditions. Operating in a continuous mode, this system could effectively treat the brewery effluent at organic loading rates (OLR) over 1...
2018: Frontiers in Microbiology
Qian Liu, Yang Yang, Xiaoxue Mei, Bingfeng Liu, Chuan Chen, Defeng Xing
Ferric iron can affect the current generation of microbial electrochemical system (MES); however, how it influences microbial biofilm formation and metabolic activity has not been reported. Here, we describe the response of microbial electrode biofilm communities to insoluble ferric iron (Fe3+ ) at different concentrations in microbial fuel cells (MFCs). Insoluble ferric iron (200μM) improved electrochemical activity of the MFCs microbial biofilms during start-up and resulted in a higher maximum power density of 0...
March 11, 2018: Science of the Total Environment
Mst Ishrat Jahan, Ryuta Tobe, Hisaaki Mihara
The extI gene in Geobacter sulfurreducens encodes a putative outer membrane channel porin, which resides within a cluster of extHIJKLMNOPQS genes. This cluster is highly conserved across the Geobacteraceae and includes multiple putative c -type cytochromes. In silico analyses of the ExtI sequence, together with Western blot analysis and proteinase protection assays, showed that it is an outer membrane protein. The expression level of ExtI did not respond to changes in osmolality and phosphate starvation. An extI -deficient mutant did not show any significant impact on fumarate or Fe(III) citrate reduction or sensitivity to β-lactam antibiotics, as compared with those of the wild-type strain...
March 11, 2018: International Journal of Molecular Sciences
Dawn E Holmes, Roberto Orelana, Ludovic Giloteaux, Li-Ying Wang, Pravin Shrestha, Kenneth Williams, Derek R Lovley, Amelia-Elena Rotaru
Previous studies of acetate-promoted bioremediation of uranium-contaminated aquifers focused on Geobacter because no other microorganisms that can couple the oxidation of acetate with U(VI) reduction had been detected in situ. Monitoring the levels of methyl CoM reductase subunit A (mcrA) transcripts during an acetate-injection field experiment demonstrated that acetoclastic methanogens from the genus Methanosarcina were enriched after 40 days of acetate amendment. The increased abundance of Methanosarcina corresponded with an accumulation of methane in the groundwater...
March 2, 2018: Microbial Ecology
Dexin Wang, Yuxing Han, Hongjun Han, Kun Li, Chunyan Xu, Haifeng Zhuang
In this study, magnetite (Fe3 O4 ), as the typical conductive material, was supplemented in anaerobic sequential batch reactor (ASBR) with the attempt to enhance pollutants removal and methane production during Fischer-Tropsch wastewater treatment. The results showed that COD removal efficiency and cumulative methane production with the addition of optimum magnetite dosage (0.4 g) were as high as 84.3 ± 2.0% and 7.46 ± 0.24 L, which were higher than other test groups (0, 0.2 and 0.6 g). Furthermore, the combination of high-throughput 16S rRNA gene pyrosequencing and metagenomic analysis in this study further confirmed that the Geobacter and Methanosaeta species were specially enriched in bacterial and archaeal community at the optimum magnetite dosage, suggesting that magnetite-mediated direct interspecies electron transfer (DIET) between Geobacter and Methanosaeta species was likely a crucial reason to promote syntrophic metabolism of propionic acid and butyric acid, and further enhance final methanogenesis...
February 23, 2018: Bioresource Technology
Yunfu Gu, Yan Bai, Quanju Xiang, Xiumei Yu, Ke Zhao, Xiaoping Zhang, Chaonan Li, Songqing Liu, Qiang Chen
Soil microbes provide important ecosystem services. Zoige Plateau wetland, the largest alpine peat wetland in the world, has suffered from serious degradation in the past 30 years. We studied the composition of the Zoige Plateau alpine wetland soil microbiota and relations among specific taxa using 16S rRNA amplicon sequencing combined with association network analysis. Compared to the pristine swamp soil, taxons DA101, Aeromicrobium, Bradyrhizobium, and Candidatus Nitrososphaera were enriched and several methanogenic Euryarchaeota were depleted in the moderately degraded meadow soil and highly degraded sandy soil...
March 1, 2018: Scientific Reports
Man Chen, Xiaofang Zhou, Xing Liu, Raymond Jianxiong Zeng, Fang Zhang, Jie Ye, Shungui Zhou
The conductivity of a biofilm is the key factor for the high current density of a bioelectrochemical system (BES). Most previous works have focused on electrode modification, but, this only benefits the microorganisms that directly contact the electrode. The low conductivity of biofilm limits the current density of the BES. In this work, gold nanoparticles (Au-NPs) were successfully fabricated in situ into a Geobacter sulfurreducens biofilm to increase the conductivity. 20 ppm NaAuCl4 (the precursor) was slowly dropped into the anode chamber at a rate of 1...
February 12, 2018: Biosensors & Bioelectronics
Pilar C Portela, Tomás M Fernandes, Joana M Dantas, Marisa R Ferreira, Carlos A Salgueiro
G. metallireducens bacterium has highly versatile respiratory pathways that provide the microorganism an enormous potential for many biotechnological applications. However, little is known about the structural and functional properties of its electron transfer components. In this work, the periplasmic cytochrome PpcA from G. metallireducens was studied in detail for the first time using complementary biophysical techniques, including UV-visible, CD and NMR spectroscopy. The results obtained showed that PpcA contains three low-spin c-type heme groups with His-His axial coordination, a feature also observed for its homologue in G...
February 24, 2018: Archives of Biochemistry and Biophysics
Pierre Champigneux, Cyril Renault-Sentenac, David Bourrier, Carole Rossi, Marie-Line Delia, Alain Bergel
Smooth and nano-rough flat gold electrodes were manufactured with controlled Ra of 0.8 and 4.5nm, respectively. Further nano-rough surfaces (Ra 4.5nm) were patterned with arrays of micro-pillars 500μm high. All these electrodes were implemented in pure cultures of Geobacter sulfurreducens, under a constant potential of 0.1V/SCE and with a single addition of acetate 10mM to check the early formation of microbial anodes. The flat smooth electrodes produced an average current density of 0.9A·m-2 . The flat nano-rough electrodes reached 2...
February 15, 2018: Bioelectrochemistry
Hyung-Sool Lee
This review explores electron transfer kinetics from an electron donor to the anode in electrically conductive biofilm anodes. Intracellular electron transfer (IET) from the donor to the anode is well described with the Monod equation. In comparison, mechanisms of extracellular electron transfer (EET) conduction are unclear yet, complicating EET kinetics. However, in biofilm anodes where potential gradient to saturated current density is less than ∼300 mV, Ohmic conduction successfully describe conductive EET mainly with biofilm conductivity (Kbio ) and biofilm thickness (Lf )...
February 22, 2018: Bioresource Technology
Yaxin Pei, Zhengsheng Yu, Jing Ji, Aman Khan, Xiangkai Li
The Yellow River is the most important water resource in northern China. In the recent past, heavy metal contamination has become severe due to industrial processes and other anthropogenic activities. In this study, riparian soil samples with varying levels of chromium (Cr) pollution severity were collected along the Gansu industrial reach of the Yellow River, including samples from uncontaminated sites (XC, XGU), slightly contaminated sites (LJX, XGD), and heavily contaminated sites (CG, XG). The Cr concentrations of these samples varied from 83...
2018: Frontiers in Microbiology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"