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Soil chemistry

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https://www.readbyqxmd.com/read/29434326/culture-independent-discovery-of-the-malacidins-as-calcium-dependent-antibiotics-with-activity-against-multidrug-resistant-gram-positive-pathogens
#1
Bradley M Hover, Seong-Hwan Kim, Micah Katz, Zachary Charlop-Powers, Jeremy G Owen, Melinda A Ternei, Jeffrey Maniko, Andreia B Estrela, Henrik Molina, Steven Park, David S Perlin, Sean F Brady
Despite the wide availability of antibiotics, infectious diseases remain a leading cause of death worldwide 1 . In the absence of new therapies, mortality rates due to untreatable infections are predicted to rise more than tenfold by 2050. Natural products (NPs) made by cultured bacteria have been a major source of clinically useful antibiotics. In spite of decades of productivity, the use of bacteria in the search for new antibiotics was largely abandoned due to high rediscovery rates2,3. As only a fraction of bacterial diversity is regularly cultivated in the laboratory and just a fraction of the chemistries encoded by cultured bacteria are detected in fermentation experiments, most bacterial NPs remain hidden in the global microbiome...
February 12, 2018: Nature Microbiology
https://www.readbyqxmd.com/read/29430920/long-term-experimental-acidification-drives-watershed-scale-shift-in-dissolved-organic-matter-composition-and-flux
#2
Michael D SanClements, Ivan J Fernandez, Robert A Lee, Joshua A Roberti, Mary Beth Adams, Garret A Rue, Diane M McKnight
Over the last several decades dissolved organic carbon concentrations (DOC) in surface waters have increased throughout much of the northern hemisphere. Several hypotheses have been proposed regarding the drivers of this phenomenon including decreased sulfur (S) deposition working via an acidity- change mechanism. Using fluorescence spectroscopy and data from two long-term (24+ years at completion of this study) whole watershed acidification experiments, that is, the Bear Brook Watershed in Maine (BBWM) and Fernow Experimental Forest in West Virginia (FEF) allowed us to control for factors other than the acidity-change mechanism (e...
February 12, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29427937/synthesis-and-characterization-of-stabilized-oxygen-releasing-cao2-nanoparticles-for-bioremediation
#3
Chia-Shen Yeh, Reuben Wang, Wen-Chi Chang, Yang-Hsin Shih
Bioremediation is one of the general methods to treat pollutants in soil, sediment, and groundwater. However, the low concentration and restricted dispersion of dissolved oxygen (DO) in these areas have limited the efficiency of remediation especially for microorganisms that require oxygen to grow. Calcium peroxide (CaO2) is one of the oxygen-releasing compounds and has been applied to magnify the remediation efficacy of polluting areas. In this study, CaO2 nanoparticles (NPs) were synthesized and evaluated by wet chemistry methods as well as dry and wet grinding processes...
February 7, 2018: Journal of Environmental Management
https://www.readbyqxmd.com/read/29424566/evaluation-of-the-tindouf-basin-region-in-southern-morocco-as-an-analog-site-for-soil-geochemistry-on-noachian-mars
#4
Elizabeth A Oberlin, Mark W Claire, Samuel P Kounaves
Locations on Earth that provide insights into processes that may be occurring or may have occurred throughout martian history are often broadly deemed "Mars analog environments." As no single locale can precisely represent a past or present martian environment, it is important to focus on characterization of terrestrial processes that produce analogous features to those observed in specific regions of Mars or, if possible, specific time periods during martian history. Here, we report on the preservation of ionic species in soil samples collected from the Tindouf region of Morocco and compare them with the McMurdo Dry Valleys of Antarctica, the Atacama Desert in Chile, the martian meteorite EETA79001, and the in situ Mars analyses from the Phoenix Wet Chemistry Laboratory (WCL)...
February 9, 2018: Astrobiology
https://www.readbyqxmd.com/read/29415535/dna-facilitates-sorption-of-polycyclic-aromatic-hydrocarbons-on-montmorillonites
#5
Chao Qin, Wei Zhang, Bing Yang, Xuwen Chen, Kang Xia, Yanzheng Gao
The sorption of polycyclic aromatic hydrocarbons (PAHs) to montmorillonites is largely influenced by their interactions with dissolved organic matter (DOM). However, the role of DOM rather than humic and fulvic acids (e.g., extracellular DNA) in the PAH sorption to soil clays is little known. Here we demonstrated that extracellular double-stranded salmon testes DNA substantially increased the sorption of phenanthrene and pyrene to Na-, Ca-, and Fe-modified montmorillonites. All PAH sorption isotherms fitted the linear and Freundlich models reasonably well (R2 = 0...
February 8, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29414747/remediation-of-heavy-hydrocarbon-impacted-soil-using-biopolymer-and-polystyrene-foam-beads
#6
Nicholas Wilton, Bonnie A Lyon-Marion, Roopa Kamath, Kevin McVey, Kurt D Pennell, Albert Robbat
A green chemistry solution is presented for the remediation of heavy hydrocarbon impacted soils. The two-phase recovery system relies on a plant-based biopolymer, which releases hydrocarbons from soil, and polystyrene foam beads, which recover them from solids and water. The efficiency of the process was demonstrated by comparisons with control experiments, where water, biopolymer, or beads alone yielded total petroleum hydrocarbon (TPH) reductions of 25%, 52%, and 58%, respectively, compared to 94% when 1...
February 2, 2018: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/29414338/nitrogen-source-track-and-associated-isotopic-dynamic-characteristic-in-a-complex-ecosystem-a-case-study-of-a-subtropical-watershed-china
#7
Zhuo Hao, Xinyu Zhang, Yang Gao, Zhiwei Xu, Fengting Yang, Xuefa Wen, Yueming Wang
By identifying the main sources of nitrate (NO3-) can obtain useful information to support the management of NO3- pollution, particularly in subtropical catchments with shallow drinking water wells. This study used water chemistry and dual stable isotopes δ15N and δ18O methods to assess seasonal and spatial variations of NO3- in precipitation, surface water, and groundwater in an agricultural and forest subtropical catchment in Jiangxi Province, China. The maximum concentrations of nitrate-nitrogen (NO3--N) and ammonium-nitrogen (NH4+-N) were 10...
January 30, 2018: Environmental Pollution
https://www.readbyqxmd.com/read/29400458/role-of-immobile-kaolinite-colloids-in-the-transport-of-heavy-metals
#8
Jongmuk Won, Susan E Burns
Predicting the transport of contaminants in porous media is crucial to protecting public health and remediating contaminated soil and groundwater. However, the prediction of contaminant transport is challenging due to the presence of mobile and immobile colloids. The work performed in this experimental investigation quantified the role of immobile clay colloids on metal transport through sets of column breakthrough experiments under varying solution chemistry, clay content, and flow rate. Georgia kaolinite was chosen as the colloidal material, and Pb(II) was chosen as the dissolved contaminant...
February 14, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29397451/the-synergistic-effect-of-calcium-on-organic-carbon-sequestration-to-ferrihydrite
#9
Tyler D Sowers, Jason W Stuckey, Donald L Sparks
Sequestration of organic carbon (OC) in environmental systems is critical to mitigating climate change. Organo-mineral associations, especially those with iron (Fe) oxides, drive the chemistry of OC sequestration and stability in soils. Short-range-ordered Fe oxides, such as ferrihydrite, demonstrate a high affinity for OC in binary systems. Calcium commonly co-associates with OC and Fe oxides in soils, though the bonding mechanism (e.g., cation bridging) and implications of the co-association for OC sequestration remain unresolved...
February 3, 2018: Geochemical Transactions
https://www.readbyqxmd.com/read/29359651/bioenergy-potential-of-eichhornia-crassipes-assessed-via-thermodynamics-and-kinetics-analyses
#10
Ifrah Afzal, Muhammad Sajjad Ahmad, Sana Malik, Muhammad Ibrahim, Omar Salim Al-Ayed, Ghulam Qadir, Huda Al Doghaither, Munazza Gull
Eichhornia crassipes is an aquatic plant well known for its role in soil reclamation due to the containment of valuable nutrients. Moreover, its biomass is an abundant and low-cost biological resource. While pyrolysis of a biomass offers one of the cleanest methods to harness the bioenergy stored in the biomass. The present study was focused on evaluating the bioenergy potential of Eichhornia crassipes via pyrolysis. Biomass of E. crassipes was collected from a municipal wastewater pond. Oven dried powdered biomass of E...
January 21, 2018: Protein and Peptide Letters
https://www.readbyqxmd.com/read/29353782/hydrochemical-characteristics-of-ground-ice-in-permafrost-regions-of-the-qinghai-tibet-plateau
#11
Weihua Wang, Tonghua Wu, Lin Zhao, Ren Li, Changwei Xie, Yongping Qiao, Huiwen Zhang, Xiaofan Zhu, Shuhua Yang, Yanhui Qin, Junming Hao
Ground ice is a distinctive feature of permafrost terrain. The vertical distribution and factors controlling the hydrochemistry of ground ice are important for studying soil moisture and salt migration during the freeze-thaw process in soil. These factors are also important components of hydrological cycles in cold regions. The hydrochemical characteristics of ground ice on the Qinghai-Tibetan Plateau (QTP) are not well known. We examined the characteristics of ground ice hydrochemistry using data from 9 soil profiles in permafrost regions of the central QTP...
January 16, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29335175/an-assessment-of-the-ca-weathering-sources-to-surface-waters-on-the-precambrian-shield-in-central-ontario
#12
Shaun Watmough
There is increasing concern over the negative ecological impacts caused by falling calcium (Ca) concentrations in lakes, particularly in central Ontario, Canada. Forecasting regional changes in lake Ca concentrations relies on accurate estimates of mineral weathering rates that are not widely available. In this study, bulk atmospheric deposition, surface water and soil chemistry along with 87Sr/86Sr isotope measurements were used to provide regional insight into weathering controls on Ca concentrations in lakes...
January 12, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29314284/the-mercury-problem-in-artisanal-and-small-scale-gold-mining
#13
Louisa J Esdaile, Justin M Chalker
Mercury-dependent artisanal and small-scale gold mining (ASGM) is the largest source of mercury pollution on Earth. In this practice, elemental mercury is used to extract gold from ore as an amalgam. The amalgam is typically isolated by hand and then heated-often with a torch or over a stove-to distill the mercury and isolate the gold. Mercury emissions from tailings and vaporised mercury exceed 1000 tonnes each year from ASGM. The health effects on the miners are dire, with inhaled mercury leading to neurological damage and other health issues...
January 3, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29313428/biosynthesis-of-silver-nanoparticles-using-novel-bacillus-sp-sbt8
#14
Tuğçe Yurtluk, Fikriye Alev Akçay, Ayşe Avcı
Biosynthesis of silver nanoparticles (AgNPs) using microorganisms is an important application of nano-biotechnology and green chemistry because of interest by pharmaceutical and food manufacturers. In this study, biosynthesis of AgNPs by a novel Bacillus strain isolated from a soil sample from Sakarya district in Turkey was investigated. Biosynthesis was performed using cell-free supernatant of the bacterium following 24 h growth. Effects of varying AgNO3 concentration (1-10 mM), pH (5-10), and temperature (30-40°C) on the synthesis of AgNPs were determined...
January 9, 2018: Preparative Biochemistry & Biotechnology
https://www.readbyqxmd.com/read/29311698/comparative-analysis-of-bones-mites-soil-chemistry-nematodes-and-soil-micro-eukaryotes-from-a-suspected-homicide-to-estimate-the-post-mortem-interval
#15
Ildikó Szelecz, Sandra Lösch, Christophe V W Seppey, Enrique Lara, David Singer, Franziska Sorge, Joelle Tschui, M Alejandra Perotti, Edward A D Mitchell
Criminal investigations of suspected murder cases require estimating the post-mortem interval (PMI, or time after death) which is challenging for long PMIs. Here we present the case of human remains found in a Swiss forest. We have used a multidisciplinary approach involving the analysis of bones and soil samples collected beneath the remains of the head, upper and lower body and "control" samples taken a few meters away. We analysed soil chemical characteristics, mites and nematodes (by microscopy) and micro-eukaryotes (by Illumina high throughput sequencing)...
January 8, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29304231/buffered-delivery-of-phosphate-to-arabidopsis-alters-responses-to-low-phosphate
#16
Meredith T Hanlon, Swayamjit Ray, Patompong Saengwilai, Dawn Luthe, Jonathan P Lynch, Kathleen M Brown
Arabidopsis has been reported to respond to phosphate (Pi) stress by arresting primary root growth and increasing lateral root branching. We developed a system to buffer Pi availability to Arabidopsis in gel media systems by charging activated aluminum oxide particles with low and sufficient concentrations of Pi, based on previous work in horticultural and sand culture systems. This system more closely mimics soil chemistry and results in different growth and transcriptional responses to Pi stress compared with plants grown in standard gel media...
January 3, 2018: Journal of Experimental Botany
https://www.readbyqxmd.com/read/29296020/linking-soil-biology-and-chemistry-in-biological-soil-crust-using-isolate-exometabolomics
#17
Tami L Swenson, Ulas Karaoz, Joel M Swenson, Benjamin P Bowen, Trent R Northen
Metagenomic sequencing provides a window into microbial community structure and metabolic potential; however, linking these data to exogenous metabolites that microorganisms process and produce (the exometabolome) remains challenging. Previously, we observed strong exometabolite niche partitioning among bacterial isolates from biological soil crust (biocrust). Here we examine native biocrust to determine if these patterns are reproduced in the environment. Overall, most soil metabolites display the expected relationship (positive or negative correlation) with four dominant bacteria following a wetting event and across biocrust developmental stages...
January 2, 2018: Nature Communications
https://www.readbyqxmd.com/read/29289770/towards-a-better-understanding-of-long-term-wood-chemistry-variations-in-old-growth-forests-a-case-study-on-ancient-pinus-uncinata-trees-from-the-pyrenees
#18
Andrea Hevia, Raúl Sánchez-Salguero, J Julio Camarero, Allan Buras, Gabriel Sangüesa-Barreda, J Diego Galván, Emilia Gutiérrez
Dendrochemical studies in old forests are still underdeveloped. Old trees growing in remote high-elevation areas far from direct human influence constitute a promising biological proxy for the long-term reconstructions of environmental changes using tree-rings. Furthermore, centennial-long chronologies of multi-elemental chemistry at inter- and intra-annual resolution are scarce. Here, we use a novel non-destructive method by applying Micro X-ray fluorescence (μXRF) to wood samples of old Pinus uncinata trees from two Pyrenean high-elevation forests growing on acidic and basic soils...
December 28, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29260812/the-hydrolysis-of-epoxides-catalyzed-by-inorganic-ammonium-salts-in-water-kinetic-evidence-for-hydrogen-bond-catalysis
#19
B Nozière, F Fache, A Maxut, B Fenet, A Baudouin, L Fine, C Ferronato
Naturally-occurring inorganic ammonium ions have been recently reported as efficient catalysts for some organic reactions in water, which contributes to the understanding of the chemistry in some natural environments (soils, seawater, atmospheric aerosols, …) and biological systems, and is also potentially interesting for green chemistry as many of their salts are cheap and non-toxic. In this work, the effect of NH4+ ions on the hydrolysis of small epoxides in water was studied kinetically. The presence of NH4+ increased the hydrolysis rate by a factor of 6 to 25 compared to pure water and these catalytic effects were shown not to result from other ions, counter-ions or from acid or base catalysis, general or specific...
December 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29251817/mitigation-of-nitrous-oxide-emissions-from-acidic-soils-by-bacillus-amyloliquefaciens-a-plant-growth-promoting-bacterium
#20
Shanghua Wu, Guoqiang Zhuang, Zhihui Bai, Yu Cen, Shengjun Xu, Haishu Sun, Xingguo Han, Xuliang Zhuang
Nitrous oxide (N2 O) is a long-lived greenhouse gas that can result in the alteration of atmospheric chemistry and cause accompanying changes in global climate. To date, many techniques have been used to mitigate the emissions of N2 O from agricultural fields, which represent one of the most important sources of N2 O. In this study, we designed a greenhouse pot experiment and a microcosmic serum bottle incubation experiment using acidic soil from a vegetable farm to study the effects of Bacillus amyloliquefaciens (BA) on plant growth and N2 O emission rates...
December 18, 2017: Global Change Biology
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