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https://www.readbyqxmd.com/read/28731479/marine-archaeal-dynamics-and-interactions-with-the-microbial-community-over-5-years-from-surface-to-seafloor
#1
Alma E Parada, Jed A Fuhrman
Marine archaea are critical contributors to global carbon and nitrogen redox cycles, but their temporal variability and microbial associations across the water column are poorly known. We evaluated seasonal variability of free living (0.2-1 μm size fraction) Thaumarchaea Marine Group I (MGI) and Euryarchaea Marine Group II (MGII) communities and their associations with the microbial community from surface to seafloor (890 m) over 5 years by 16S rRNA V4-V5 gene sequencing. MGI and MGII communities demonstrated distinct compositions at different depths, and seasonality at all depths...
July 21, 2017: ISME Journal
https://www.readbyqxmd.com/read/28730188/tert-butyl-nitrite-tbn-as-the-n-atom-source-for-the-synthesis-of-substituted-cinnolines-with-2-vinylanilines-and-a-relevant-mechanism-was-studied
#2
XiaoBo Pang, LianBiao Zhao, DaGang Zhou, Ping Yong He, ZhenYu An, Ji Xiang Ni, RuLong Yan
A green method to synthesize cinnolines by 6π electrocyclic reaction with alkenyl amines and TBN has been developed. TBN plays a dual role both as a nitrogen atom source and an oxidant in this procedure. Relevant mechanism experiments reveal that the reaction proceeds through electrocyclic reaction and with diazo hydroxide as a key intermediate.
July 21, 2017: Organic & Biomolecular Chemistry
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/28729387/leg-blood-flow-is-impaired-during-small-muscle-mass-exercise-in-copd-patients
#4
Ulrik Winning Iepsen, Gregers Druedal Wibe Munch, Mette Rugbjerg, Camilla Koch Ryrsø, Niels Secher, Ylva Hellsten, Peter Lange, Bente Klarlund Pedersen, Pia Thaning, Stefan P Mortensen
Skeletal muscle blood flow is regulated to match the oxygen demand and dysregulation could contribute to exercise intolerance in patients with COPD. We measured leg hemodynamics and metabolites from vasoactive compounds in muscle interstitial fluid and plasma at rest, during one-legged knee-extensor exercise, and during arterial infusions of sodium nitroprusside (SNP) and acetylcholine (ACh), respectively. Ten patients with moderate to severe COPD and eight age- and sex matched healthy controls were studied...
July 20, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28728975/continuous-nitrogen-removal-by-a-single-stage-reactor-packed-with-ring-laced-string-medium
#5
Masahiro Tatara, Shu Ishikawa, Yoshiyuki Ueno
The efficiency of nitrogen removal by a partial-nitritation/anammox (PNA) reaction was investigated using a packed-bed reactor in which ring-laced strings were used as the supporting medium. A stable population of PNA microorganisms was established from typical activated sludge, after less than two months of acclimation in the packed-bed reactor, by applying a high nitrogen-loading rate (NLR: 0.53 kg/m(3)/d) and short hydraulic retention time (HRT: 1.8 h). The stability of reactor performance was confirmed in industrial wastewater (IW), demonstrating a nitrogen removal efficiency (NRE) of greater than 77% during 260 days of continuous operation, between 0...
July 17, 2017: Journal of Bioscience and Bioengineering
https://www.readbyqxmd.com/read/28728409/heterogeneous-reactions-between-toluene-and-no2-on-mineral-particles-under-simulated-atmospheric-conditions
#6
Hejingying Niu, Kezhi Li, Biwu Chu, Wenkang Su, Junhua Li
Heterogeneous reactions between organic and inorganic gases with aerosols are important to the study of smog occurrence and development. In this study, heterogeneous reactions between toluene and NO2 with three atmospheric mineral particles in the presence or absence of UV light were investigated. The three mineral particles were SiO2, α-Fe2O3 and BS (butlerite and szmolnokite). In a dark environment, benzaldehyde was produced on α-Fe2O3. For BS, nitrotoluene and benzaldehyde were obtained. No aromatic products were produced in the absence of NO2 in the system...
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
#7
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/28727028/production-management-and-the-environment-symposium-measurement-and-mitigation-of-reactive-nitrogen-species-from-swine-and-poultry-production
#8
W Powers, M Capelari
Reactive nitrogen (Nr) species include oxides of nitrogen [N; nitric oxide, nitrogen dioxide and nitrous oxide (NO)], anions (nitrate and nitrite), and amine derivatives [ammonia (NH), ammonium salts and urea]. Of the different Nr species, air emissions from swine and poultry facilities are predominantly NH followed by NO. Excreta emissions are NH, ammonium ions, and urea with trace amounts of nitrate and nitrite. Farm systems and practices that handle manure as a wet product without pH modification favor almost exclusive NH production...
May 2017: Journal of Animal Science
https://www.readbyqxmd.com/read/28726705/spatiotemporal-distribution-of-nitrogen-and-phosphorus-in-alpine-lakes-in-the-sanjiangyuan-region-of-the-tibetan-plateau
#9
Su-Jin Lu, Jian-Huan Si, Chuan-Ying Hou, Yu-Si Li, Meng-Meng Wang, Xiao-Xia Yan, Meng Xie, Jin-Xu Sun, Bai-Jie Chen, Shu-Sen Li
To provide a theoretical basis for alpine source lake protection, ten samples were taken from each lake annually from 2012 to 2015. Each year, the various species of nitrogen and phosphorus nutrients were measured. The average contents of nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total phosphorus, and total nitrogen in the four lakes are 0.195-0.0 mg/L, 0.038-0.143 mg/L, 0.004-0.168 mg/L, 0.006-0.740 mg/L, and 0.050-0.547 mg/L, respectively. The total phosphorus contents in Eling Lake, Longbao Lake and Sea Star were higher than Class I water quality standards, and the total nitrogen contents in Eling Lake, Sea Star and Zhaling Lake were higher than Class I water quality standards as well...
July 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/28726125/nitrogen-assimilation-in-denitrifier-bacillus-azotoformans-lmg-9581-t
#10
Yihua Sun, Paul De Vos, Anne Willems
Until recently, it has not been generally known that some bacteria can contain the gene inventory for both denitrification and dissimilatory nitrate (NO3(-))/nitrite (NO2(-)) reduction to ammonium (NH4(+)) (DNRA). Detailed studies of these microorganisms could shed light on the differentiating environmental drivers of both processes without interference of organism-specific variation. Genome analysis of Bacillus azotoformans LMG 9581(T) shows a remarkable redundancy of dissimilatory nitrogen reduction, with multiple copies of each denitrification gene as well as DNRA genes nrfAH, but a reduced capacity for nitrogen assimilation, with no nas operon nor amtB gene...
July 19, 2017: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/28724105/nitrifying-kinetics-and-the-persistence-of-nitrite-in-the-seine-river-france
#11
M Raimonet, T Cazier, V Rocher, A M Laverman
Although a higher oxidation rate for nitrite than for ammonia generally prevents nitrite accumulation in oxic waters, nitrite concentrations in the Seine River (1-31 μM) exceed European norms. We investigated the kinetics of in situ ammonia- and nitrite-oxidizing communities in river water and wastewater treatment plant (WWTP) effluents to determine the role of pelagic nitrification in the origin and persistence of nitrite downstream of Paris. The main source of nitrite is the major Parisian WWTP, and its persistence, up to tens of kilometers downstream of the plant, is explained by low ammonia and nitrite oxidation rates and high river flow...
May 2017: Journal of Environmental Quality
https://www.readbyqxmd.com/read/28720728/disguised-as-a-sulfate-reducer-growth-of-the-deltaproteobacterium-desulfurivibrio-alkaliphilus-by-sulfide-oxidation-with-nitrate
#12
Casper Thorup, Andreas Schramm, Alyssa J Findlay, Kai W Finster, Lars Schreiber
This study demonstrates that the deltaproteobacterium Desulfurivibrio alkaliphilus can grow chemolithotrophically by coupling sulfide oxidation to the dissimilatory reduction of nitrate and nitrite to ammonium. Key genes of known sulfide oxidation pathways are absent from the genome of D. alkaliphilus Instead, the genome contains all of the genes necessary for sulfate reduction, including a gene for a reductive-type dissimilatory bisulfite reductase (DSR). Despite this, growth by sulfate reduction was not observed...
July 18, 2017: MBio
https://www.readbyqxmd.com/read/28720275/nitrite-accumulation-in-continuous-flow-partial-autotrophic-denitrification-reactor-using-sulfide-as-electron-donor
#13
Chunshuang Liu, Wenfei Li, Xuechen Li, Dongfeng Zhao, Bin Ma, Yongqiang Wang, Fang Liu, Duu-Jong Lee
The nitrite accumulation in handling nitrate and sulfide-laden wastewater in a continuous-flow upflow anaerobic sludge blanket reactor was studied. At sulfide/nitrate-nitrogen ratio of 1:0.76 and loading rates of 1.2kg-Sm(-3)d(-1) and 0.4kg-Nm(-3)d(-1), the elemental sulfur and nitrite accumulation rates peaked at 90% and 70%, respectively, with Acrobacter, Azoarcus and Thauera presenting the functional strains in the studied reactor. The accumulated nitrite was proposed a promising feedstock for anaerobic ammonia oxidation process...
July 8, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28718056/aeration-control-strategies-to-stimulate-simultaneous-nitrification-denitrification-via-nitrite-during-the-formation-of-aerobic-granular-sludge
#14
Thomas Dobbeleers, Jolien D'aes, Solange Miele, Michel Caluwé, Veerle Akkermans, Dominique Daens, Luc Geuens, Jan Dries
In this study, a sequencing batch reactor (SBR), treating synthetic wastewater (COD/N = 5), was operated in two stages. During stage I, an aeration control strategy based on oxygen uptake rate (OUR) was applied, to accomplish nitrogen removal via nitrite >80%. In stage II, the development of aerobic granular sludge (AGS) was examined while two aeration control strategies (OUR and pH slope) maintained the nitrite pathway and optimized the simultaneous nitrification-denitrification (SND) performance. Stimulation of slow-growing organisms, (denitrifying) polyphosphate-accumulating organisms (D)PAO and (denitrifying) glycogen-accumulating organisms (D)GAO leads to full granulation (at day 200, SVI10 = 47...
July 17, 2017: Applied Microbiology and Biotechnology
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
#15
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/28717380/response-of-local-nitric-oxide-release-to-manual-acupuncture-and-electrical-heat-in-humans-effects-of-reinforcement-methods
#16
Sheng-Xing Ma, Paul C Lee, Thomas L Anderson, Xi-Yan Li, Isabelle Z Jiang
This study was to examine the influences of manual acupuncture (MA) and electrical heat corresponding to reinforcing methods on nitric oxide (NO) release over the skin regions in humans. A device with collecting solution was taped to the skin surface along pericardium (PC) or lung (LU) meridian. Acupuncture needles were gently inserted into PC 4 with reinforcing stimulation (low force/rate) for 20 minutes in the MA group. LU11 on the finger was heated (43-44°C) by electrical heat for 20 minutes. Biocapture was consecutively conducted for two 20-minute intervals during and after each treatment...
2017: Evidence-based Complementary and Alternative Medicine: ECAM
https://www.readbyqxmd.com/read/28716941/cryptic-oxygen-cycling-in-anoxic-marine-zones
#17
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/28716929/nitric-oxide-is-an-obligate-bacterial-nitrification-intermediate-produced-by-hydroxylamine-oxidoreductase
#18
Jonathan D Caranto, Kyle M Lancaster
Ammonia (NH3)-oxidizing bacteria (AOB) emit substantial amounts of nitric oxide (NO) and nitrous oxide (N2O), both of which contribute to the harmful environmental side effects of large-scale agriculture. The currently accepted model for AOB metabolism involves NH3 oxidation to nitrite (NO2(-)) via a single obligate intermediate, hydroxylamine (NH2OH). Within this model, the multiheme enzyme hydroxylamine oxidoreductase (HAO) catalyzes the four-electron oxidation of NH2OH to NO2(-) We provide evidence that HAO oxidizes NH2OH by only three electrons to NO under both anaerobic and aerobic conditions...
July 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28716629/characterization-of-novel-bacillus-strain-n31-from-mariculture-water-capable-of-halophilic-heterotrophic-nitrification-aerobic-denitrification
#19
Fei Huang, Luqing Pan, Na Lv, Xianming Tang
The development of an intensive aquaculture industry has been accompanied by increasing environmental impacts, especially nitrogen pollution. In this study, a novel halophilic bacterium capable of heterotrophic nitrification and aerobic denitrification was isolated from mariculture water and identified as Bacillus litoralis N31. The efficiency of ammonium, nitrite and nitrate removal by N31 were 86.3%, 89.3% and 89.4%, respectively, after a 48-h cultivation in sole N-source medium with initial nitrogen approximately 20 mg/L...
July 14, 2017: Journal of Bioscience and Bioengineering
https://www.readbyqxmd.com/read/28716476/influence-of-polycyclic-aromatic-hydrocarbons-on-nitrate-reduction-capability-in-mangrove-sediments
#20
Shan Jiang, Yan Su, Haoliang Lu, Hui Jia, Jingchun Liu, Chongling Yan
In the present study, we investigated the influence of phenanthrene (PHE), a three-ring polycyclic aromatic hydrocarbon (PAH) compound, on nitrate (NO3(-)) reduction processes in mangrove sediments using microcosms. After 10days, nitrate/nitrite reductase activity and abundance of narG and nirS significantly decreased in the bulk sediment at both 10/50mgPHEkg(-1) contamination groups. In the rhizosphere, abundance of narG, nirS and nirK markedly declined at PHE treated sediments, while the drop in reductase activity at 10mgkg(-1) PHE treatment was insignificant...
July 14, 2017: Marine Pollution Bulletin
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