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https://www.readbyqxmd.com/read/28098207/using-13-c-isotopes-to-explore-denitrification-dependent-anaerobic-methane-oxidation-in-a-paddy-peatland
#1
Yao Shi, Zhongqiang Wang, Chunguang He, Xinyu Zhang, Lianxi Sheng, Xiaodong Ren
Peatlands are organic-matter-rich but nitrogen-limited natural systems, the carbon/nitrogen (C/N) status of which are subject to increasing exposure from long-term nitrate (NO3(-)) fertilizer inputs and atmospheric nitrogen (N) deposits. To manage and protect these unique environments, an improved understanding of denitrification-dependent anaerobic oxidation of methane (DAMO) in peatlands is needed. In this study, we used stable isotope measurements and incubation with NO3(-) additions to facilitate an investigation and comparison of the potential DAMO rates in a paddy-peatland that has been influenced by N fertilizer over 40 years and an undisturbed peatland in northeast China...
January 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28097050/microbial-communities-mediating-algal-detritus-turnover-under-anaerobic-conditions
#2
Jessica M Morrison, Chelsea L Murphy, Kristina Baker, Richard M Zamor, Steve J Nikolai, Shawn Wilder, Mostafa S Elshahed, Noha H Youssef
BACKGROUND: Algae encompass a wide array of photosynthetic organisms that are ubiquitously distributed in aquatic and terrestrial habitats. Algal species often bloom in aquatic ecosystems, providing a significant autochthonous carbon input to the deeper anoxic layers in stratified water bodies. In addition, various algal species have been touted as promising candidates for anaerobic biogas production from biomass. Surprisingly, in spite of its ecological and economic relevance, the microbial community involved in algal detritus turnover under anaerobic conditions remains largely unexplored...
2017: PeerJ
https://www.readbyqxmd.com/read/28096511/paper-of-note-in-science-355-6321
#3
Annalisa M VanHook
This week's article shows that a demethylase reduces the ability of the opportunistic pathogen Pseudomonas aeruginosa to form biofilms under anoxic conditions.
January 17, 2017: Science Signaling
https://www.readbyqxmd.com/read/28096405/selenium-isotopes-record-extensive-marine-suboxia-during-the-great-oxidation-event
#4
Michael A Kipp, Eva E Stüeken, Andrey Bekker, Roger Buick
It has been proposed that an "oxygen overshoot" occurred during the early Paleoproterozoic Great Oxidation Event (GOE) in association with the extreme positive carbon isotopic excursion known as the Lomagundi Event. Moreover, it has also been suggested that environmental oxygen levels then crashed to very low levels during the subsequent extremely negative Shunga-Francevillian carbon isotopic anomaly. These redox fluctuations could have profoundly influenced the course of eukaryotic evolution, as eukaryotes have several metabolic processes that are obligately aerobic...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28094921/uranium-redox-transformations-after-u-vi-coprecipitation-with-magnetite-nanoparticles
#5
Ivan Pidchenko, Kristina O Kvashnina, Tadahiro Yokosawa, Nicolas Finck, Sebastian Bahl, Dieter Schild, Robert Polly, Elke Bohnert, Andre Rossberg, Jörg Göttlicher, Kathy Dardenne, Jörg Rothe, Thorsten Schäfer, Horst Geckeis, Tonya Vitova
Uranium redox states and speciation in magnetite nanoparticles co-precipitated with U(VI) for uranium loadings varying from 1000 to 10000 ppm are investigated by X-ray absorption spectroscopy (XAS). It is demonstrated that the U M4 high energy resolution X-ray absorption near edge structure (HR-XANES) method is capable to clearly characterize U(IV), U(V) and U(VI) existing simultaneously in the same sample. The contributions of the three different uranium redox states are quantified with the iterative transformation factor analysis (ITFA) method...
January 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28089857/na-k-atpase-activity-in-the-anoxic-turtle-trachemys-scripta-brain-at-different-acclimation-temperature
#6
Jonathan A W Stecyk, Anthony P Farrell, Matti Vornanen
Survival of prolonged anoxia requires a balance between cellular ATP demand and anaerobic ATP supply from glycolysis, especially in critical tissues such as the brain. To add insight into the ATP demand of the brain of the anoxia-tolerant red-eared slider turtle (Trachemys scripta) during prolonged periods of anoxic submergence, we quantified and compared the number of Na(+)-K(+)-ATPase units and their molecular activity in brain tissue from turtles acclimated to either 21°C or 5°C and exposed to either normoxia or anoxia (6h 21°C; 14 d at 5°C)...
January 12, 2017: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
https://www.readbyqxmd.com/read/28087525/capturing-compositional-variation-in-denitrifying-communities-a-multiple-primer-approach-that-includes-autotrophic-denitrifying-epsilonproteobacteria
#7
Sheryl A Murdock, S Kim Juniper
: Denitrifying Epsilonproteobacteria may dominate nitrogen loss processes in marine habitats with intense redox gradients but assessment of their importance is limited by currently available primers for nitrite reductase genes. Nine new primers targeting the nirS gene of denitrifying Epsilonproteobacteria were designed and tested for use in sequencing and quantitative PCR on two microbial mat samples (Vent 2 and Vent 4) from the Calypso hydrothermal vent field, Bay of Plenty, New Zealand...
January 13, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28087421/physiology-anaerobes-and-the-origin-of-mitosing-cells-50-years-on
#8
William F Martin
Endosymbiotic theory posits that some organelles or structures of eukaryotic cells stem from free-living prokaryotes that became endosymbionts within a host cell. Endosymbiosis has a long and turbulent history of controversy and debate going back over 100 years. The 1967 paper by Lynn Sagan (later Lynn Margulis) forced a reluctant field to take endosymbiotic theory seriously and to incorporate it into the fabric of evolutionary thinking. Margulis envisaged three cellular partners associating in series at eukaryotic origin: the host (an engulfing bacterium), the mitochondrion (a respiring bacterium), and the flagellum (a spirochaete), with lineages descended from that flagellated eukaryote subsequently acquiring plastids from cyanobacteria, but on multiple different occasions in her 1967 account...
January 10, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28077869/age-extent-and-carbon-storage-of-the-central-congo-basin-peatland-complex
#9
Greta C Dargie, Simon L Lewis, Ian T Lawson, Edward T A Mitchard, Susan E Page, Yannick E Bocko, Suspense A Ifo
Peatlands are carbon-rich ecosystems that cover just three per cent of Earth's land surface, but store one-third of soil carbon. Peat soils are formed by the build-up of partially decomposed organic matter under waterlogged anoxic conditions. Most peat is found in cool climatic regions where unimpeded decomposition is slower, but deposits are also found under some tropical swamp forests. Here we present field measurements from one of the world's most extensive regions of swamp forest, the Cuvette Centrale depression in the central Congo Basin...
January 11, 2017: Nature
https://www.readbyqxmd.com/read/28077774/tropical-ancient-dna-reveals-relationships-of-the-extinct-bahamian-giant-tortoise-chelonoidis-alburyorum
#10
Christian Kehlmaier, Axel Barlow, Alexander K Hastings, Melita Vamberger, Johanna L A Paijmans, David W Steadman, Nancy A Albury, Richard Franz, Michael Hofreiter, Uwe Fritz
Ancient DNA of extinct species from the Pleistocene and Holocene has provided valuable evolutionary insights. However, these are largely restricted to mammals and high latitudes because DNA preservation in warm climates is typically poor. In the tropics and subtropics, non-avian reptiles constitute a significant part of the fauna and little is known about the genetics of the many extinct reptiles from tropical islands. We have reconstructed the near-complete mitochondrial genome of an extinct giant tortoise from the Bahamas (Chelonoidis alburyorum) using an approximately 1 000-year-old humerus from a water-filled sinkhole (blue hole) on Great Abaco Island...
January 11, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28075523/extreme-rainfall-and-snowfall-alter-responses-of-soil-respiration-to-nitrogen-fertilization-a-3-year-field-experiment
#11
Zengming Chen, Yehong Xu, Xuhui Zhou, Jianwu Tang, Yakov Kuzyakov, Hongyan Yu, Jianling Fan, Weixin Ding
Extreme precipitation is predicted to be more frequent and intense accompanying global warming, and may have profound impacts on soil respiration (Rs) and its components, i.e., autotrophic (Ra) and heterotrophic (Rh) respiration. However, how natural extreme rainfall or snowfall events affect these fluxes are still lacking, especially under nitrogen (N) fertilization. In this study, extreme rainfall and snowfall events occurred during a 3-year field experiment, allowing us to examine their effects on the response of Rs, Rh and Ra to N supply...
January 11, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28070815/microbial-transformation-of-intracellular-dissolved-organic-matter-from-microcystis-aeruginosa-and-its-effect-on-the-binding-of-pyrene-under-oxic-and-anoxic-conditions
#12
Chenghu Yang, Yangzhi Liu, Yaxian Zhu, Yong Zhang
The environmental behaviour and the bioavailability of polycyclic aromatic hydrocarbons (PAHs) are strongly affected by dissolved organic matter (DOM) in aquatic environments. In this study, we investigated the dynamics of the bioavailability and character of the intracellular DOM (IDOM) from Microcystis aeruginosa (M. aeruginosa-IDOM) during 10 days oxic and anoxic incubations by spectroscopy. Subsequently, the binding affinity of pyrene with the initial/altered M. aeruginosa-IDOM was estimated by fluorescence quenching method...
January 10, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28070677/potential-activity-of-subglacial-microbiota-transported-to-anoxic-river-delta-sediments
#13
Karen A Cameron, Marek Stibal, Nikoline S Olsen, Andreas B Mikkelsen, Bo Elberling, Carsten S Jacobsen
The Watson River drains a portion of the SW Greenland ice sheet, transporting microbial communities from subglacial environments to a delta at the head of Søndre Strømfjord. This study investigates the potential activity and community shifts of glacial microbiota deposited and buried under layers of sediments within the river delta. A long-term (12-month) incubation experiment was established using Watson River delta sediment under anaerobic conditions, with and without CO2/H2 enrichment. Within CO2/H2-amended incubations, sulphate depletion and a shift in the microbial community to a 52% predominance of Desulfosporosinus meridiei by day 371 provides evidence for sulphate reduction...
January 9, 2017: Microbial Ecology
https://www.readbyqxmd.com/read/28070216/metabolism-in-anoxic-permeable-sediments-is-dominated-by-eukaryotic-dark-fermentation
#14
Michael F Bourke, Philip J Marriott, Ronnie N Glud, Harald Hasler-Sheetal, Manoj Kamalanathan, John Beardall, Chris Greening, Perran L M Cook
Permeable sediments are common across continental shelves and are critical contributors to marine biogeochemical cycling. Organic matter in permeable sediments is dominated by microalgae, which as eukaryotes have different anaerobic metabolic pathways to prokaryotes such as bacteria and archaea. Here we present analyses of flow-through reactor experiments showing that dissolved inorganic carbon is produced predominantly as a result of anaerobic eukaryotic metabolic activity. In our experiments, anaerobic production of dissolved inorganic carbon was consistently accompanied by large dissolved H2 production rates, suggesting the presence of fermentation...
January 2017: Nature Geoscience
https://www.readbyqxmd.com/read/28069941/uranium-iv-adsorption-by-natural-organic-matter-in-anoxic-sediments
#15
Sharon E Bone, James J Dynes, John Cliff, John R Bargar
Uranium is an important carbon-free fuel source and environmental contaminant that accumulates in the tetravalent state, U(IV), in anoxic sediments, such as ore deposits, marine basins, and contaminated aquifers. However, little is known about the speciation of U(IV) in low-temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV) was assumed to exist predominantly as the sparingly soluble mineral uraninite (UO2+x) in anoxic sediments; however, studies now show that this is not often the case...
January 9, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28068534/potential-effects-of-loading-nano-zero-valent-iron-discharged-on-membrane-fouling-in-an-anoxic-oxic-membrane-bioreactor
#16
Lijie Zhou, Weiqin Zhuang, Xin Wang, Ke Yu, Shufang Yang, Siqing Xia
A laboratory-scale submerged anoxic-oxic membrane bioreactor for municipal wastewater was operated to investigate the potential effects of loading suspended nano zero valent iron (nZVI, 25 and 50 mg/L) discharged on the membrane fouling. nZVI transformed rapidly into Fe(n+), generated reactive oxygen species (ROS) and caused oxidative stress. This result rapidly led to the cell lysis and bacteria death, and further resulted in the decrease of biomass and extracellular polymeric substances (EPS). nZVI also thinned the membrane fouling layer...
January 3, 2017: Water Research
https://www.readbyqxmd.com/read/28067645/assessment-of-the-endogenous-respiration-rate-and-the-observed-biomass-yield-for-methanol-fed-denitrifying-bacteria-under-anoxic-and-aerobic-conditions
#17
Jamal Alikhani, Ahmed Al-Omari, Haydee De Clippeleir, Sudhir Murthy, Imre Takacs, Arash Massoudieh
In this study, the endogenous respiration rate and the observed biomass yield of denitrifying methylotrophic biomass were estimated through measuring changes in denitrification rates (DNR) as a result of maintaining the biomass under methanol deprived conditions. For this purpose, activated sludge biomass from a full-scale wastewater treatment plant was kept in 10-L batch reactors for 8 days under fully aerobic and anoxic conditions at 20 °C without methanol addition. To investigate temperature effects, another biomass sample was placed under starvation conditions over a period of 10 days under aerobic conditions at 25 °C...
January 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/28067643/biological-phosphorus-removal-in-anoxic-aerobic-sequencing-batch-reactor-with-starch-as-sole-carbon-source
#18
Dacheng Luo, Linjiang Yuan, Lun Liu, Lu Chai, Xin Wang
In traditional biological phosphorus removal (BPR), phosphorus release in anaerobic stage is the prerequisite of phosphorus excessive uptake in aerobic conditions. Moreover, when low molecular weight of the organic substance such as volatile fatty acids (VFAs) is scarce in bulk liquid or anaerobic condition does not exist, phosphate accumulating organisms (PAOs) have difficulty removing phosphorus. However, in this work, phosphorus removal in two anoxic-aerobic sequencing batch reactors (SBRs) was observed when starch was supplied as a sole carbon source...
January 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/28067226/syntrophic-anaerobic-photosynthesis-via-direct-interspecies-electron-transfer
#19
Phuc T Ha, Stephen R Lindemann, Liang Shi, Alice C Dohnalkova, James K Fredrickson, Michael T Madigan, Haluk Beyenal
Microbial phototrophs, key primary producers on Earth, use H2O, H2, H2S and other reduced inorganic compounds as electron donors. Here we describe a form of metabolism linking anoxygenic photosynthesis to anaerobic respiration that we call 'syntrophic anaerobic photosynthesis'. We show that photoautotrophy in the green sulfur bacterium Prosthecochloris aestaurii can be driven by either electrons from a solid electrode or acetate oxidation via direct interspecies electron transfer from a heterotrophic partner bacterium, Geobacter sulfurreducens...
January 9, 2017: Nature Communications
https://www.readbyqxmd.com/read/28059435/acetoin-production-via-unbalanced-fermentation-in-shewanella-oneidensis
#20
Thea Bursac, Jeffrey A Gralnick, Johannes Gescher
This study describes the realization of an anoxic acetoin production process using the proteobacterium Shewanella oneidensis. Fermentative processes are of high biotechnological relevance since they offer high productivity and a low percentage of substrate consumption for anabolic processes. Nevertheless, the range of compounds that can be produced as sole end product of a fermentative process is limited, since the average oxidation state of substrate and products has to be identical in the absence of an external electron acceptor...
January 6, 2017: Biotechnology and Bioengineering
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