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Nitrate reducing bacteria

Michaela L Sundqvist, Jon O Lundberg, Eddie Weitzberg
The nitrate-nitrite-nitric oxide pathway has emerged as a significant source of nitric oxide (NO) bioactivity. Dietary intake of inorganic nitrate has a number of cardiovascular effects as well as a decrease in oxygen cost during exercise and a reduction in resting metabolic rate (RMR). Oral bacteria have a key role in bioactivation of inorganic nitrate since they catalyse the conversion of salivary nitrate to the more reactive nitrite anion. Recent studies demonstrate that blood pressure increases with the use of an antiseptic mouthwash, indicating that endogenous, NO-synthase derived nitrate is recycled into nitrite and NO, sufficiently to modulate cardiovascular function...
October 18, 2016: Nitric Oxide: Biology and Chemistry
Jayeeta Sarkar, Sufia K Kazy, Abhishek Gupta, Avishek Dutta, Balaram Mohapatra, Ajoy Roy, Paramita Bera, Adinpunya Mitra, Pinaki Sar
Nutrient deficiency severely impairs the catabolic activity of indigenous microorganisms in hydrocarbon rich environments (HREs) and limits the rate of intrinsic bioremediation. The present study aimed to characterize the microbial community in refinery waste and evaluate the scope for biostimulation based in situ bioremediation. Samples recovered from the wastewater lagoon of Guwahati refinery revealed a hydrocarbon enriched [high total petroleum hydrocarbon (TPH)], oxygen-, moisture-limited, reducing environment...
2016: Frontiers in Microbiology
B L Read-Daily, F Sabba, J P Pavissich, R Nerenberg
Nitrous oxide (N2O) is a powerful greenhouse gas emitted from wastewater treatment, as well as natural systems, as a result of biological nitrification and denitrification. While denitrifying bacteria can be a significant source of N2O, they can also reduce N2O to N2. More information on the kinetics of N2O formation and reduction by denitrifying bacteria is needed to predict and quantify their impact on N2O emissions. In this study, kinetic parameters were determined for Paracoccus pantotrophus, a common denitrifying bacterium...
December 2016: AMB Express
F M Helaly, S M El-Sawy, A I Hashem, A A Khattab, R M Mourad
PURPOSE: Nanosilver-silicone hydrogel (NAgSiH) composites for contact lenses were synthesized to asses the antimicrobial effects. METHODS: Silicone hydrogel (SiH) films were synthesized followed by impregnation in silver nitrate solutions (10, 20, 30, 40, 60, 80ppm) and in-situ chemical reduction of silver ions using sodium borohydride (NaBH4). The silver nano particles (AgNPS) were identified by UV-vis absorption spectroscopy, Energy-dispersive X-ray spectroscopy (EDX) mapping and EDX spectrum...
September 29, 2016: Contact Lens & Anterior Eye: the Journal of the British Contact Lens Association
Johannes F Imhoff
During the past decades, tremendous advances have been made in the possibilities to study the diversity of microbial communities in the environment. The development of methods to study these communities on the basis of 16S rRNA gene sequences analysis was a first step into the molecular analysis of environmental communities and the study of biodiversity in natural habitats. A new dimension in this field was reached with the introduction of functional genes of ecological importance and the establishment of genetic tools to study the diversity of functional microbial groups and their responses to environmental factors...
May 24, 2016: Microorganisms
Ian T Cadby, Susan A Ibrahim, Matthew Faulkner, David J Lee, Douglas Browning, Stephen J Busby, Andrew L Lovering, Melanie R Stapleton, Jeffrey Green, Jeffrey A Cole
In silico analyses identified a Crp/Fnr family transcription factor (HcpR) in sulfate-reducing bacteria that controls expression of the hcp gene, which encodes the hybrid cluster protein and contributes to nitrosative stress responses. There is only one hcpR gene in the model sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough, but two copies in Desulfovibrio desulfuricans 27774, which can use nitrate as an alternative electron acceptor to sulfate. Structures of the D. desulfuricans hcpR1, hcpR2 and hcp operons are reported...
September 27, 2016: Molecular Microbiology
Xi-Jun Xu, Chuan Chen, Ai-Jie Wang, Bing-Jie Ni, Wan-Qian Guo, Ye Yuan, Cong Huang, Xu Zhou, Dong-Hai Wu, Duu-Jong Lee, Nan-Qi Ren
A mathematical model of carbon, nitrogen and sulfur removal (C-N-S) from industrial wastewater was constructed considering the interactions of sulfate-reducing bacteria (SRB), sulfide-oxidizing bacteria (SOB), nitrate-reducing bacteria (NRB), facultative bacteria (FB), and methane producing archaea (MPA). For the kinetic network, the bioconversion of C-N by heterotrophic denitrifiers (NO3(-)→NO2(-)→N2), and that of C-S by SRB (SO4(2-)→S(2-)) and SOB (S(2-)→S(0)) was proposed and calibrated based on batch experimental data...
August 31, 2016: Journal of Hazardous Materials
Jun Zeng, Kai Lou, Cui-Jing Zhang, Jun-Tao Wang, Hang-Wei Hu, Ju-Pei Shen, Li-Mei Zhang, Li-Li Han, Tao Zhang, Qin Lin, Phillip M Chalk, Ji-Zheng He
Structural succession and its driving factors for nitrogen (N) cycling microbial communities during the early stages of soil development (0-44 years) were studied along a chronosequence in the glacial forelands of the Tianshan Mountain No.1 glacier in the arid and semi-arid region of central Asia. We assessed the abundance and population of functional genes affiliated with N-fixation (nifH), nitrification (bacterial and archaeal amoA), and denitrification (nirK/S and nosZ) in a glacier foreland using molecular methods...
2016: Frontiers in Microbiology
Soumya Soman, J G Ray
Biological approach to synthesis of metal nanoparticles using aqueous leaf extract is a highly relevant and recent theme in nanotechnological research. Phytosynthesized AgNPs have better inhibitory and antimicrobial effects compared to aqueous leaf extract and silver nitrate. In the present investigation crystalline silver nanoparticles (AgNPs) with size of 10nm have been successfully synthesized using aqueous leaf extract (AQLE) of Ziziphus oenoplia (L.) Mill., which act as both reducing as well as capping agent...
October 2016: Journal of Photochemistry and Photobiology. B, Biology
Barbara Hohensinn, Renate Haselgrübler, Ulrike Müller, Verena Stadlbauer, Peter Lanzerstorfer, Gerald Lirk, Otmar Höglinger, Julian Weghuber
BACKGROUND: Dietary inorganic nitrate (NO3(-)) and its reduced forms nitrite (NO2(-)) and nitric oxide (NO), respectively, are of critical importance for host defense in the oral cavity. High concentrations of salivary nitrate are linked to a lower prevalence of caries due to growth inhibition of cariogenic bacteria. OBJECTIVE: In-vitro studies suggest that the formation of antimicrobial NO results in an increase of the pH preventing erosion of tooth enamel. The purpose of this study was to prove this effect in-vivo...
September 1, 2016: Nitric Oxide: Biology and Chemistry
Jing Han, Yasser M Sanad, Joanna Deck, John B Sutherland, Zhong Li, Matthew J Walters, Norma Duran, Matthew R Holman, Steven L Foley
: There are an estimated 8 million users of smokeless tobacco products (STPs) in the United States, and yet limited data on microbial populations within these products exist. To better understand the potential microbiological risks associated with STP use, a study was conducted to provide a baseline microbiological profile of STPs. A total of 90 samples, representing 15 common STPs, were purchased in metropolitan areas in Little Rock, AR, and Washington, DC, in November 2012, March 2013, and July 2013...
October 15, 2016: Applied and Environmental Microbiology
Wenfeng Wang, Lixiang Cao, Hongming Tan, Renduo Zhang
The aim of this study was to investigate the effects of single and mixed culture of denitrifying fungi, bacteria, and actinobacteria on nitrogen removal and N2O emission in treatment of wastewater. Denitrifying endophytes of Pseudomonas sp. B2, Streptomyces sp. A9, and Fusarium sp. F3 isolated from rice plants were utilized for treatment of synthetic wastewater containing nitrate and nitrite. Experiments were conducted under shaking and static conditions. Results showed that under the static condition, more than 97 % of nitrate removal efficiencies were reached in all the treatments containing B2...
August 25, 2016: Applied Microbiology and Biotechnology
Chioma C Obi, Sunday A Adebusoye, Esther O Ugoji, Mathew O Ilori, Olukayode O Amund, William J Hickey
Estuarine sediments are significant repositories of anthropogenic contaminants, and thus knowledge of the impacts of pollution upon microbial communities in these environments is important to understand potential effects on estuaries as a whole. The Lagos lagoon (Nigeria) is one of Africa's largest estuarine ecosystems, and is impacted by hydrocarbon pollutants and other industrial and municipal wastes. The goal of this study was to elucidate microbial community structure in Lagos lagoon sediments to identify groups that may be adversely affected by pollution, and those that may serve as degraders of environmental contaminants, especially polycyclic aromatic hydrocarbons (PAHs)...
2016: Frontiers in Microbiology
Taiki Mori, Daiki Yokoyama, Kanehiro Kitayama
An incubation study was conducted to test the effects of phosphorus (P) addition on nitrous oxide (N2O) emissions from the soils taken from two tropical rain forests established on different parent materials [meta-sedimentary (MS) and ultrabasic (UB) rock] on Mt. Kinabalu, Borneo. Earlier studies suggest that the forest on UB soils is more strongly limited by P than that on MS soils is. In MS soils, P addition significantly reduced N2O emissions. Since neither ammonium (NH4 (+)) nor nitrate (NO3 (-)) contents were reduced by P addition, we assumed that the decrease in N2O emissions were not due to the previously-reported mechanism: P addition stimulated microbial nitrogen (N) immobilization and collateral inorganic N consumption, reducing resources for producing N2O...
2016: SpringerPlus
Magdalena R Osburn, Katherine S Dawson, Marilyn L Fogel, Alex L Sessions
Hydrogen atoms from water and food are incorporated into biomass during cellular metabolism and biosynthesis, fractionating the isotopes of hydrogen-protium and deuterium-that are recorded in biomolecules. While these fractionations are often relatively constant in plants, large variations in the magnitude of fractionation are observed for many heterotrophic microbes utilizing different central metabolic pathways. The correlation between metabolism and lipid δ(2)H provides a potential basis for reconstructing environmental and ecological parameters, but the calibration dataset has thus far been limited mainly to aerobes...
2016: Frontiers in Microbiology
Mauricio Arenas-Salinas, Joaquín I Vargas-Pérez, Wladimir Morales, Camilo Pinto, Pablo Muñoz-Díaz, Fabián A Cornejo, Benoit Pugin, Juan M Sandoval, Waldo A Díaz-Vásquez, Claudia Muñoz-Villagrán, Fernanda Rodríguez-Rojas, Eduardo H Morales, Claudio C Vásquez, Felipe A Arenas
The tellurium oxyanion tellurite (TeO3 (2-)) is extremely harmful for most organisms. It has been suggested that a potential bacterial tellurite resistance mechanism would consist of an enzymatic, NAD(P)H-dependent, reduction to the less toxic form elemental tellurium (Te(0)). To date, a number of enzymes such as catalase, type II NADH dehydrogenase and terminal oxidases from the electron transport chain, nitrate reductases, and dihydrolipoamide dehydrogenase (E3), among others, have been shown to display tellurite-reducing activity...
2016: Frontiers in Microbiology
Katja Laufer, Hans Røy, Bo Barker Jørgensen, Andreas Kappler
: Nitrate-reducing Fe(II)-oxidizing microorganisms were described for the first time ca. 20 years ago. Most pure cultures of nitrate-reducing Fe(II) oxidizers can oxidize Fe(II) only under mixotrophic conditions, i.e., when an organic cosubstrate is provided. A small number of nitrate-reducing Fe(II)-oxidizing cultures have been proposed to grow autotrophically, but unambiguous evidence for autotrophy has not always been provided. Thus, it is still unclear whether or to what extent Fe(II) oxidation coupled to nitrate reduction is an enzymatically catalyzed and energy-yielding autotrophic process or whether Fe(II) is abiotically oxidized by nitrite from heterotrophic nitrate reduction...
October 15, 2016: Applied and Environmental Microbiology
Abeer Hashem, Elsayed F Abd Allah, Abdulaziz A Alqarawi, Asma A Al-Huqail, Stephan Wirth, Dilfuza Egamberdieva
Microbes living symbiotically in plant tissues mutually cooperate with each other by providing nutrients for proliferation of the partner organism and have a beneficial effect on plant growth. However, few studies thus far have examined the interactive effect of endophytic bacteria and arbuscular mycorrhizal fungi (AMF) in hostile conditions and their potential to improve plant stress tolerance. In this study, we investigated how the synergistic interactions of endophytic bacteria and AMF affect plant growth, nodulation, nutrient acquisition and stress tolerance of Acacia gerrardii under salt stress...
2016: Frontiers in Microbiology
Hiroyasu Tsutsuki, Minkyung Jung, Tianli Zhang, Katsuhiko Ono, Tomoaki Ida, Kohei Kunieda, Hideshi Ihara, Takaaki Akaike, Tomohiro Sawa
8-Nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP) is a nitrated cGMP derivative formed in response to nitric oxide (NO) and reactive oxygen species (ROS). It can cause a post-translational modification (PTM) of protein thiols through cGMP adduction (protein S-guanylation). Accumulating evidence has suggested that, in mammals, S-guanylation of redox-sensor proteins may implicate in regulation of adaptive responses against ROS-associated oxidative stress. Occurrence as well as protein targets of S-guanylation in bacteria remained unknown, however...
September 9, 2016: Biochemical and Biophysical Research Communications
Johnny R Soares, Noriko A Cassman, Anna M Kielak, Agata Pijl, Janaína B Carmo, Kesia S Lourenço, Hendrikus J Laanbroek, Heitor Cantarella, Eiko E Kuramae
Nitrous oxide (N2O) from nitrogen fertilizers applied to sugarcane has high environmental impact on ethanol production. This study aimed to determine the main microbial processes responsible for the N2O emissions from soil fertilized with different N sources, to identify options to mitigate N2O emissions, and to determine the impacts of the N sources on the soil microbiome. In a field experiment, nitrogen was applied as calcium nitrate, urea, urea with dicyandiamide or 3,4 dimethylpyrazone phosphate nitrification inhibitors (NIs), and urea coated with polymer and sulfur (PSCU)...
2016: Scientific Reports
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