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Nitrate reducing bacteria

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https://www.readbyqxmd.com/read/27884109/cloning-functional-expression-and-characterization-of-a-bifunctional-3-hydroxybutanal-dehydrogenase-reductase-involved-in-acetone-metabolism-by-desulfococcus-biacutus
#1
Jasmin Frey, Hendrik Rusche, Bernhard Schink, David Schleheck
BACKGROUND: The strictly anaerobic, sulfate-reducing bacterium Desulfococcus biacutus can utilize acetone as sole carbon and energy source for growth. Whereas in aerobic and nitrate-reducing bacteria acetone is activated by carboxylation with CO2 to acetoacetate, D. biacutus involves CO as a cosubstrate for acetone activation through a different, so far unknown pathway. Proteomic studies indicated that, among others, a predicted medium-chain dehydrogenase/reductase (MDR) superfamily, zinc-dependent alcohol dehydrogenase (locus tag DebiaDRAFT_04514) is specifically and highly produced during growth with acetone...
November 25, 2016: BMC Microbiology
https://www.readbyqxmd.com/read/27881860/in-situ-restoration-of-one-stage-partial-nitritation-anammox-process-deteriorated-by-nitrate-build-up-via-elevated-substrate-levels
#2
Xiaolong Wang, Dawen Gao
The one-stage partial nitritation and anammox process (PN/A) has been a promising microbial process to remove ammonia from wastewater especially with low carbon/nitrogen ratio. The main breakdown was the deterioration caused by overgrowth of nitrite oxidizing bacteria (NOB) resulting effluent nitrate build-up in the PN/A process. This study presented an in-situ restoring strategy for suppressing NOB activity in a one-stage granular PN/A system deteriorated over 2 months, using elevated concentrations of substrates (ammonia and nitrite) under limited dissolved oxygen level...
November 24, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27877167/polycyclic-aromatic-hydrocarbon-induced-changes-in-bacterial-community-structure-under-anoxic-nitrate-reducing-conditions
#3
Sophie-Marie Martirani-Von Abercron, Daniel Pacheco, Patricia Benito-Santano, Patricia Marín, Silvia Marqués
Although bacterial anaerobic degradation of mono-aromatic compounds has been characterized in depth, the degradation of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene has only started to be understood in sulfate reducing bacteria, and little is known about the anaerobic degradation of PAHs in nitrate reducing bacteria. Starting from a series of environments which had suffered different degrees of hydrocarbon pollution, we used most probable number (MPN) enumeration to detect and quantify the presence of bacterial communities able to degrade several PAHs using nitrate as electron acceptor...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27872324/from-nitrate-to-nitric-oxide-the-role-of-salivary-glands-and-oral-bacteria
#4
X M Qu, Z F Wu, B X Pang, L Y Jin, L Z Qin, S L Wang
The salivary glands and oral bacteria play an essential role in the conversion process from nitrate (NO3(-)) and nitrite (NO2(-)) to nitric oxide (NO) in the human body. NO is, at present, recognized as a multifarious messenger molecule with important vascular and metabolic functions. Besides the endogenous L-arginine pathway, which is catalyzed by complex NO synthases, nitrate in food contributes to the main extrinsic generation of NO through a series of sequential steps (NO3(-)-NO2(-)-NO pathway). Up to 25% of nitrate in circulation is actively taken up by the salivary glands, and as a result, its concentration in saliva can increase 10- to 20-fold...
December 2016: Journal of Dental Research
https://www.readbyqxmd.com/read/27857202/napb-in-excess-inhibits-growth-of-shewanella-oneidensis-by-dissipating-electrons-of-the-quinol-pool
#5
Miao Jin, Qianyun Zhang, Yijuan Sun, Haichun Gao
Shewanella, a group of ubiquitous bacteria renowned for respiratory versatility, thrive in environments where various electron acceptors (EAs) of different chemical and physiological characteristics coexist. Despite being extensively studied, we still know surprisingly little about strategies by which multiple EAs and their interaction define ecophysiology of these bacteria. Previously, we showed that nitrite inhibits growth of the genus representative Shewanella oneidensis on fumarate and presumably some other CymA (quinol dehydrogenase)-dependent EAs by reducing cAMP production, which in turn leads to lowered expression of nitrite and fumarate reductases...
November 18, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27847498/intracellular-nitrate-of-marine-diatoms-as-a-driver-of-anaerobic-nitrogen-cycling-in-sinking-aggregates
#6
Anja Kamp, Peter Stief, Laura A Bristow, Bo Thamdrup, Ronnie N Glud
Diatom-bacteria aggregates are key for the vertical transport of organic carbon in the ocean. Sinking aggregates also represent pelagic microniches with intensified microbial activity, oxygen depletion in the center, and anaerobic nitrogen cycling. Since some of the aggregate-forming diatom species store nitrate intracellularly, we explored the fate of intracellular nitrate and its availability for microbial metabolism within anoxic diatom-bacteria aggregates. The ubiquitous nitrate-storing diatom Skeletonema marinoi was studied as both axenic cultures and laboratory-produced diatom-bacteria aggregates...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27822557/migraines-are-correlated-with-higher-levels-of-nitrate-nitrite-and-nitric-oxide-reducing-oral-microbes-in-the-american-gut-project-cohort
#7
Antonio Gonzalez, Embriette Hyde, Naseer Sangwan, Jack A Gilbert, Erik Viirre, Rob Knight
Nitrates, such as cardiac therapeutics and food additives, are common headache triggers, with nitric oxide playing an important role. Facultative anaerobic bacteria in the oral cavity may contribute migraine-triggering levels of nitric oxide through the salivary nitrate-nitrite-nitric oxide pathway. Using high-throughput sequencing technologies, we detected observable and significantly higher abundances of nitrate, nitrite, and nitric oxide reductase genes in migraineurs versus nonmigraineurs in samples collected from the oral cavity and a slight but significant difference in fecal samples...
September 2016: MSystems
https://www.readbyqxmd.com/read/27812355/abundance-and-diversity-of-denitrifying-and-anammox-bacteria-in-seasonally-hypoxic-and-sulfidic-sediments-of-the-saline-lake-grevelingen
#8
Yvonne A Lipsewers, Ellen C Hopmans, Filip J R Meysman, Jaap S Sinninghe Damsté, Laura Villanueva
Denitrifying and anammox bacteria are involved in the nitrogen cycling in marine sediments but the environmental factors that regulate the relative importance of these processes are not well constrained. Here, we evaluated the abundance, diversity, and potential activity of denitrifying, anammox, and sulfide-dependent denitrifying bacteria in the sediments of the seasonally hypoxic saline Lake Grevelingen, known to harbor an active microbial community involved in sulfur oxidation pathways. Depth distributions of 16S rRNA gene, nirS gene of denitrifying and anammox bacteria, aprA gene of sulfur-oxidizing and sulfate-reducing bacteria, and ladderane lipids of anammox bacteria were studied in sediments impacted by seasonally hypoxic bottom waters...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27810735/profound-differences-between-humans-and-rodents-in-the-ability-to-concentrate-salivary-nitrate-implications-for-translational-research
#9
Marcelo F Montenegro, Michaela L Sundqvist, Carina Nihlén, Michael Hezel, Mattias Carlström, Eddie Weitzberg, Jon O Lundberg
In humans dietary circulating nitrate accumulates rapidly in saliva through active transport in the salivary glands. By this mechanism resulting salivary nitrate concentrations are 10-20 times higher than in plasma. In the oral cavity nitrate is reduced by commensal bacteria to nitrite, which is subsequently swallowed and further metabolized to nitric oxide (NO) and other bioactive nitrogen oxides in blood and tissues. This entero-salivary circulation of nitrate is central in the various NO-like effects observed after ingestion of inorganic nitrate...
October 25, 2016: Redox Biology
https://www.readbyqxmd.com/read/27781173/green-synthesis-of-silver-nanoparticles-in-aloe-vera-plant-extract-prepared-by-a-hydrothermal-method-and-their-synergistic-antibacterial-activity
#10
Patcharaporn Tippayawat, Nutthakritta Phromviyo, Parichart Boueroy, Apiwat Chompoosor
BACKGROUND: There is worldwide interest in silver nanoparticles (AgNPs) synthesized by various chemical reactions for use in applications exploiting their antibacterial activity, even though these processes exhibit a broad range of toxicity in vertebrates and invertebrates alike. To avoid the chemical toxicity, biosynthesis (green synthesis) of metal nanoparticles is proposed as a cost-effective and environmental friendly alternative. Aloe vera leaf extract is a medicinal agent with multiple properties including an antibacterial effect...
2016: PeerJ
https://www.readbyqxmd.com/read/27769826/effects-of-antiseptic-mouthwash-on-resting-metabolic-rate-a-randomized-double-blind-crossover-study
#11
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
https://www.readbyqxmd.com/read/27708623/biostimulation-of-indigenous-microbial-community-for-bioremediation-of-petroleum-refinery-sludge
#12
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
https://www.readbyqxmd.com/read/27699705/kinetics-of-nitrous-oxide-n2o-formation-and-reduction-by-paracoccus-pantotrophus
#13
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
https://www.readbyqxmd.com/read/27693238/synthesis-and-characterization-of-nanosilver-silicone-hydrogel-composites-for-inhibition-of-bacteria-growth
#14
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
https://www.readbyqxmd.com/read/27681913/new-dimensions-in-microbial-ecology-functional-genes-in-studies-to-unravel-the-biodiversity-and-role-of-functional-microbial-groups-in-the-environment
#15
REVIEW
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
https://www.readbyqxmd.com/read/27671526/regulation-sensory-domains-and-roles-of-two-desulfovibrio-desulfuricans-atcc27774-crp-family-transcription-factors-hcpr1-and-hcpr2-in-response-to-nitrosative-stress
#16
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
https://www.readbyqxmd.com/read/27669378/mathematical-modeling-of-simultaneous-carbon-nitrogen-sulfur-removal-from-industrial-wastewater
#17
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
https://www.readbyqxmd.com/read/27625641/primary-succession-of-nitrogen-cycling-microbial-communities-along-the-deglaciated-forelands-of-tianshan-mountain-china
#18
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
https://www.readbyqxmd.com/read/27619740/silver-nanoparticles-synthesized-using-aqueous-leaf-extract-of-ziziphus-oenoplia-l-mill-characterization-and-assessment-of-antibacterial-activity
#19
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
https://www.readbyqxmd.com/read/27593618/sustaining-elevated-levels-of-nitrite-in-the-oral-cavity-through-consumption-of-nitrate-rich-beetroot-juice-in-young-healthy-adults-reduces-salivary-ph
#20
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
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