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https://www.readbyqxmd.com/read/28731532/formate-and-nitrate-utilization-in-enterobacter-aerogenes-for-semi-anaerobic-production-of-isobutanol
#1
Hwi-Min Jung, Yong Hwan Kim, Min-Kyu Oh
Anaerobic bioprocessing is preferred because of its economic advantages. However, low productivity and decreased growth of the host strain have limited the use of the anaerobic process. Anaerobic respiration can be applied to anoxic processing using formate and nitrate metabolism to improve the productivity of value-added metabolites. We constructed isobutanol-producing strains using Enterobacter aerogenes as a host strain by metabolic engineering approaches. The byproduct pathway (ldhA, budA, and pflB) was knocked out, and heterologous keto-acid decarboxylase (kivD) and alcohol dehydrogenase (adhA) were expressed along with the L-valine synthesis pathway (ilvCD and budB)...
July 21, 2017: Biotechnology Journal
https://www.readbyqxmd.com/read/28731391/malpractice-litigation-following-spine-surgery
#2
Alan H Daniels, Roy Ruttiman, Adam E M Eltorai, J Mason DePasse, Bielinsky A Brea, Mark A Palumbo
OBJECTIVE Adverse events related to spine surgery sometimes lead to litigation. Few studies have evaluated the association between spine surgical complications and medical malpractice proceedings, outcomes, and awards. The aim of this study was to identify the most frequent causes of alleged malpractice in spine surgery and to gain insight into patient demographic and clinical characteristics associated with medical negligence litigation. METHODS A search for "spine surgery" spanning February 1988 to May 2015 was conducted utilizing the medicolegal research service VerdictSearch (ALM Media Properties, LLC)...
July 21, 2017: Journal of Neurosurgery. Spine
https://www.readbyqxmd.com/read/28729646/climate-oscillations-reflected-within-the-microbiome-of-arabian-sea-sediments
#3
William D Orsi, Marco J L Coolen, Cornelia Wuchter, Lijun He, Kuldeep D More, Xabier Irigoien, Guillem Chust, Carl Johnson, Jordon D Hemingway, Mitchell Lee, Valier Galy, Liviu Giosan
Selection of microorganisms in marine sediment is shaped by energy-yielding electron acceptors for respiration that are depleted in vertical succession. However, some taxa have been reported to reflect past depositional conditions suggesting they have experienced weak selection after burial. In sediments underlying the Arabian Sea oxygen minimum zone (OMZ), we performed the first metagenomic profiling of sedimentary DNA at centennial-scale resolution in the context of a multi-proxy paleoclimate reconstruction...
July 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28728413/detection-occurrence-and-fate-of-fluorotelomer-alcohols-in-municipal-wastewater-treatment-plants
#4
Hongrui Chen, Hui Peng, Min Yang, Jianying Hu, Yu Zhang
Fluorotelomer alcohols (FTOHs) are the most well-known precursors of perfluoroalkyl carboxylic acids (PFCAs), but limited information is available on their occurrence and fate in municipal wastewater treatment plants (WWTPs). The occurrence of FTOHs was investigated in influent, secondary effluent and sludge of 12 municipal WWTPs in nine cities of China. FTOHs were detected in all WWTPs, and 8:2 FTOH was the predominant congener, with concentrations of 2.10-11.0 ng/L, 3.05-12.4 ng/L and 0.36-1.91 ng/g dry weight in the influent, secondary effluent and sludge, respectively...
July 21, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28728124/thin-ferrihydrite-sediment-capping-sequestrates-phosphorus-experiencing-redox-conditions-in-a-shallow-temperate-lacustrine-wetland
#5
Yuanchun Zou, Michael R Grace, Keryn L Roberts, Xiaofei Yu
Synthesized ferrihydrite (Fh) with the dosages of 0.3, 0.6 and 0.9 cm thickness (labeled as Fh, 2Fh and 3Fh respectively, equivalent to 248-774 g/m(2)) were deployed to serve as the reactive capping layer covering the Ornamental Lake sediments, the Royal Botanic Garden of Melbourne. The sediments were exposed to an alternating regime of oxic/anoxic conditions using laboratory reactors for 45 days. Dynamics of dissolved oxygen (DO), pH, filterable reactive phosphorus (FRP), filterable ammonium (NH4(+)), nitrate and nitrite (NOx), total dissolved nitrogen (TDN) and dissolved iron (Fe) of overlying water were examined...
July 12, 2017: Chemosphere
https://www.readbyqxmd.com/read/28728112/reductive-defluorination-of-perfluorooctanoic-acid-by-titanium-iii-citrate-with-vitamin-b12-and-copper-nanoparticles
#6
Yu-Chi Lee, Yi-Pei Chen, Meng-Jia Chen, Jeff Kuo, Shang-Lien Lo
Perfluorooctanoic acid (PFOA) is widespread in the environment, which causes serious health and safety concerns. A mechanistic study on reductive defluorination of PFOA by titanium(III) citrate in the presence of catalysts was conducted. Vitamin B12 was used to catalyze reduction reactions by shuttling electrons from a reducing agent (electron donor) to PFOA to produce a Co-carbon bond intermediates. In the presence of copper nanoparticles, a precursor complex, B12-C7F14COOH, adsorbed on the metal surface, followed by a hydrogenolytic reaction to form less-fluorinated products...
June 29, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28727811/factors-limiting-sulfolane-biodegradation-in-contaminated-subarctic-aquifer-substrate
#7
Christopher P Kasanke, Mary Beth Leigh
Sulfolane, a water-soluble organosulfur compound, is used industrially worldwide and is associated with one of the largest contaminated groundwater plumes in the state of Alaska. Despite being widely used, little is understood about the degradation of sulfolane in the environment, especially in cold regions. We conducted aerobic and anaerobic microcosm studies to assess the biological and abiotic sulfolane degradation potential of contaminated subarctic aquifer groundwater and sediment from Interior Alaska...
2017: PloS One
https://www.readbyqxmd.com/read/28726573/investigating-variations-of-fluorescent-dissolved-organic-matter-in-wastewater-treatment-using-synchronous-fluorescence-spectroscopy-combined-with-principal-component-analysis-and-two-dimensional-correlation
#8
Hongwei Pan, Huibin Yu, Yanan Wang, Ruixia Liu, Hongjun Lei
Synchronous fluorescence spectroscopy (SFS) combined with principal component analysis (PCA) and two-dimensional (2D) correlation was applied to investigate removal efficiencies and variations of dissolved organic matter (DOM) fractions in the wastewater treatment plant (WWTP) with an A2O craft. A decreasing order of total removal efficiencies was tyrosine-like fluorescence component (89.58%) > humic-like fluorescence component (39.83%) > tryptophan-like fluorescence component (36.89%) > microbial humic-like fluorescence component (12...
July 20, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28726128/on-the-response-of-the-baltic-proper-to-changes-of-the-total-phosphorus-supply
#9
Anders Stigebrandt
Using a time-dependent phosphorus (P) budget model for the Baltic proper, describing sources and sinks at the external borders of the water column, one may compute the e-folding time T of the adjustment of the winter surface water P concentration c 1 to abruptly changed total P supply. The restoration time TR = 3T is introduced as a practical measure of the time it takes to achieve 95% of the change of c 1 towards the final, equilibrium, state c 1e. The P budget model, including an internal source emanating from deep anoxic bottoms, also shows that c 1e is proportional to the total P supply to the water column...
July 19, 2017: Ambio
https://www.readbyqxmd.com/read/28725484/logarithmic-sensing-in-bacillus-subtilis-aerotaxis
#10
Filippo Menolascina, Roberto Rusconi, Vicente I Fernandez, Steven Smriga, Zahra Aminzare, Eduardo D Sontag, Roman Stocker
Aerotaxis, the directed migration along oxygen gradients, allows many microorganisms to locate favorable oxygen concentrations. Despite oxygen's fundamental role for life, even key aspects of aerotaxis remain poorly understood. In Bacillus subtilis, for example, there is conflicting evidence of whether migration occurs to the maximal oxygen concentration available or to an optimal intermediate one, and how aerotaxis can be maintained over a broad range of conditions. Using precisely controlled oxygen gradients in a microfluidic device, spanning the full spectrum of conditions from quasi-anoxic to oxic (60 n mol/l-1 m mol/l), we resolved B...
2017: NPJ Systems Biology and Applications
https://www.readbyqxmd.com/read/28717594/effect-of-freshwater-mussels-on-the-vertical-distribution-of-anaerobic-ammonia-oxidizers-and-other-nitrogen-transforming-microorganisms-in-upper-mississippi-river-sediment
#11
Ellen M Black, Michael S Chimenti, Craig L Just
Targeted qPCR and non-targeted amplicon sequencing of 16S rRNA genes within sediment layers identified the anaerobic ammonium oxidation (anammox) niche and characterized microbial community changes attributable to freshwater mussels. Anammox bacteria were normally distributed (Shapiro-Wilk normality test, W-statistic =0.954, p = 0.773) between 1 and 15 cm depth and were increased by a factor of 2.2 (p < 0.001) at 3 cm below the water-sediment interface when mussels were present. Amplicon sequencing of sediment at depths relevant to mussel burrowing (3 and 5 cm) showed that mussel presence reduced observed species richness (p = 0...
2017: PeerJ
https://www.readbyqxmd.com/read/28717330/an-experimental-evaluation-of-adaptogenic-potential-of-standardized-epipremnum-aureum-leaf-extract
#12
Sreemoy Kanti Das, Pinaki Sengupta, Mohd Shahimi Mustapha, Md Moklesur Rahman Sarker
BACKGROUND: Stress is a normal part of everyday life but chronic stress can lead to a variety of stress-related illnesses including hypertension, anxiety, and depression. In the present investigation, standardized leaf extract of Epipremnumaureum was evaluated for its anti-stress potential. MATERIALS AND METHODS: For the evaluation of anti-stress activity, groups of mice (n = 6) were subjected to forced swim stress and anoxic stress tolerance test in mice 1h after daily treatment of E...
April 2017: Journal of Pharmacy & Bioallied Sciences
https://www.readbyqxmd.com/read/28716941/cryptic-oxygen-cycling-in-anoxic-marine-zones
#13
Emilio Garcia-Robledo, Cory C Padilla, Montserrat Aldunate, Frank J Stewart, Osvaldo Ulloa, Aurélien Paulmier, Gerald Gregori, Niels Peter Revsbech
Oxygen availability drives changes in microbial diversity and biogeochemical cycling between the aerobic surface layer and the anaerobic core in nitrite-rich anoxic marine zones (AMZs), which constitute huge oxygen-depleted regions in the tropical oceans. The current paradigm is that primary production and nitrification within the oxic surface layer fuel anaerobic processes in the anoxic core of AMZs, where 30-50% of global marine nitrogen loss takes place. Here we demonstrate that oxygenic photosynthesis in the secondary chlorophyll maximum (SCM) releases significant amounts of O2 to the otherwise anoxic environment...
July 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28715772/stability-of-single-dispersed-silver-nanoparticles-in-natural-and-synthetic-freshwaters-effects-of-dissolved-oxygen
#14
Xiaoyan Zou, Penghui Li, Jie Lou, Xiaoyan Fu, Hongwu Zhang
Silver nanoparticles (AgNPs) are increasingly used in various commercial products. This increased use raises ecological concerns because of the large release of AgNPs into the environment. Once released, the local water chemistry has the potential to influence the environmental fates and behaviors of AgNPs. The impacts of dissolved oxygen and natural organic matter (NOM) on the dissolution and stability of AgNPs were investigated in synthetic and natural freshwaters for 7 days. In synthetic freshwater, the aggregation of AgNPs occurred due to the compression of the electric double layer, accompanied by the dissolution of AgNPs...
July 14, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28712781/pressurized-microcystis-can-help-to-remove-nitrate-from-eutrophic-water
#15
Yingying Huang, Xuechu Chen, Panpan Li, Guiqin Chen, Lin Peng, Liping Pan
The aim of this study was to investigate the feasibility of using harmful cyanobacterium Microcystis to help remove nitrate from eutrophic water. The results showed that after treatment by pressurization at 0.4MPa, Microcystis quickly sank to the bottom. Pressurization did not significantly affect the viability of Microcystis and this cyanobacterium maintained high viability over three days under dark/anoxic conditions. Meanwhile, the amount of dissolved organic carbon (DOC) secreted from living Microcystis cells reached 2...
July 6, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28712344/interaction-of-graphene-oxide-nano-sheets-and-landfill-leachate-bacterial-culture
#16
Nafise Jamialahmadi, Edwin Safari, Majid Baghdadi
Interaction of graphene oxide (GO) and municipal landfill leachate bacterial culture was investigated. In aerobic conditions, stepwise addition of GO concentration to 60 mg/L increased the oxygen uptake rate coefficient. However, increasing GO concentration to 100 mg/L slightly decreased the oxygen uptake rate coefficient. When anoxic conditions developed, GO suspensions decreased the total bacterial activity and the substrate consumption. The Raman spectroscopy confirmed the chemical reduction of GO during exposure to bacteria; nonetheless, the extent of reduction in anoxic conditions was more than that in aerobic conditions...
July 17, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28711802/two-stage-anoxic-oxic-combined-membrane-bioreactor-system-for-landfill-leachate-treatment-pollutant-removal-performances-and-microbial-community
#17
Jianbo Liu, Haibo Zhang, Panyue Zhang, Yan Wu, Xiying Gou, Yonghui Song, Zhiyong Tian, Guangming Zeng
In this study, a laboratory-scale two-stage anoxic/oxic (A/O) combined membrane bioreactor (MBR) was operated for 113d for the treatment of landfill leachate. The average removal of chemical oxygen demand (COD), ammonia (NH4(+)-N) and total nitrogen (TN) achieved 80.60%, 99.04% and 74.87%, respectively. A mass balance evaluation suggested that the removal of COD, NH4(+)-N and TN occurred mainly in the second A/O process, and the total removal capacity of COD, NH4(+)-N and TN were 125.60g/d, 24.35g/d and 22...
July 4, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28710998/the-potential-multiple-mechanisms-and-microbial-communities-in-simultaneous-nitrification-and-denitrification-process-treating-high-carbon-and-nitrogen-concentration-saline-wastewater
#18
Jiale Wang, Benzhou Gong, Yingmu Wang, Yuhui Wen, Jian Zhou, Qiang He
A simultaneous nitrification and denitrification (SND) process in sequencing batch biofilm reactor (SBBR) was established to treat high carbon and nitrogen saline wastewater in this study. Acetate, glucose and an organic mixture were applied as organic sources in three SBBRs, achieving average total nitrogen removal efficiency of 97.15%, 63.94% and 94.99% during 120days' operation, respectively. The underlying nitrogen removal mechanisms were investigated by 16S rRNA sequencing and batch tests. Results showed different carbon sources had great impact on microbial communities, and led to different nitrogen removal mechanism...
June 26, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28710982/occurrence-fate-and-mass-balance-of-different-classes-of-pharmaceuticals-and-personal-care-products-in-an-anaerobic-anoxic-oxic-wastewater-treatment-plant-in-xiamen-china
#19
Muhammad Ashfaq, Yan Li, Yuwen Wang, Wenjie Chen, Han Wang, Xiangqiang Chen, Wei Wu, Zhenyi Huang, Chang-Ping Yu, Qian Sun
In this study, the occurrence and fate of 49 pharmaceuticals and personal care products (PPCPs) were investigated in an anaerobic-anoxic-oxic (A2/O) wastewater treatment plant (WWTP) for seven consecutive days using 24-h composite sampling technique. Special emphasis was placed to understand the distribution of PPCPs in dissolved and adsorbed phase, and to evaluate PPCP fate in different treatment units. Among the 49 PPCPs, 40 PPCPs in influent, 36 in effluent, 29 in sludge and 23 in suspended solids were detected at least once during sampling...
July 7, 2017: Water Research
https://www.readbyqxmd.com/read/28710913/expression-and-promoter-methylation-of-succinate-dehydrogenase-and-fumarase-genes-in-maize-under-anoxic-conditions
#20
Alexander T Eprintsev, Dmitry N Fedorin, Maria A Dobychina, Abir U Igamberdiev
Succinate dehydrogenase (SDH) and fumarase enzyme activity and expression of genes encoding the SDH subunits A (Sdh1-2), B (Sdh2-3), C (Sdh3), D (Sdh4) and the mitochondrial (Fum1) and cytosolic (Fum2) isoforms of fumarase were quantified in maize (Zea mays L.) seedlings exposed to atmospheres of air (control), N2, and CO2. The catalytic activity of SDH gradually declined in plants exposed to N2 atmospheres, with ∼40% activity remaining after 24h. In seedlings incubated in CO2, the suppression was even more pronounced...
July 4, 2017: Journal of Plant Physiology
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