Nanogram nitrite and nitrate determination in environmental and biological materials by vanadium(III) reduction with chemiluminescence detection

Braman, Robert S.; Hendrix, Steven A.

doi:10.1021/ac00199a007

Cited by 806 publications

(503 citation statements)

References 7 publications

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“…Dissolved inorganic carbon and ammonium were determined using flow injection analysis (Hall and Aller, 1992). The sum of nitrate and nitrite was quantified according to Braman and Hendrix (1989) using an NOx analyser equipped with a chemiluminescence detector (Model CLD 66,Eco Physics,Dürnten,Switzerland). pH and concentrations of dissolved O 2 and total sulphide (S tot = [S 2 − ]+[HS − ]+[H 2 S]) were determined with microsensors.…”

Section: Water Chemistrymentioning

confidence: 99%

Structure and function of natural sulphide-oxidizing microbial mats under dynamic input of light and chemical energy

et al. 2015

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We studied the interaction between phototrophic and chemolithoautotrophic sulphide-oxidizing microorganisms in natural microbial mats forming in sulphidic streams. The structure of these mats varied between two end-members: one characterized by a layer dominated by large sulphur-oxidizing bacteria (SOB; mostly Beggiatoa-like) on top of a cyanobacterial layer (B/C mats) and the other with an inverted structure (C/B mats). C/B mats formed where the availability of oxygen from the water column was limited (o5 μM). Aerobic chemolithotrophic activity of the SOB depended entirely on oxygen produced locally by cyanobacteria during high light conditions. In contrast, B/C mats formed at locations where oxygen in the water column was comparatively abundant (445 μM) and continuously present. Here SOB were independent of the photosynthetic activity of cyanobacteria and outcompeted the cyanobacteria in the uppermost layer of the mat where energy sources for both functional groups were concentrated. Outcompetition of photosynthetic microbes in the presence of light was facilitated by the decoupling of aerobic chemolithotrophy and oxygenic phototrophy. Remarkably, the B/C mats conserved much less energy than the C/B mats, although similar amounts of light and chemical energy were available. Thus ecosystems do not necessarily develop towards optimal energy usage. Our data suggest that, when two independent sources of energy are available, the structure and activity of microbial communities is primarily determined by the continuous rather than the intermittent energy source, even if the time-integrated energy flux of the intermittent energy source is greater.

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Section: Water Chemistrymentioning

confidence: 99%

Structure and function of natural sulphide-oxidizing microbial mats under dynamic input of light and chemical energy

et al. 2015

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“…was quantified as NO after reduction in hot VCl 3 (Braman and Hendrix, 1989), and sulfide was quantified according to Cline (1969) after trapping in a 20% (w/v) zinc acetate solution.…”

Section: Analyticalmentioning

confidence: 99%

Denitrification in the water column of the central Baltic Sea

Dalsgaard

Brabandere

Hall

2013

Geochimica et Cosmochimica Acta

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Removal of fixed nitrogen in the water column of the eastern Gotland Basin, central Baltic Sea, was studied during two cruises in September 2008 and August 2010. The water column was stratified with anoxic sulfidic bottom water meeting oxic nitrate containing water at the oxic-anoxic interface. Anammox was never detected whereas denitrification was found in all incubations from anoxic depths and occurred immediately below the oxic-anoxic interface. Sulfide (H 2 S + HS À + S 2À ) was in most cases the only electron donor for denitrification but, in contrast to previous findings, denitrification was in some situations driven by organic matter alone. Nitrous oxide (N 2 O) became an increasingly important product of denitrification with increasing sulfide concentration and was >80% of the total N gas formation at 10 lM sulfide. The potential rates of denitrification measured in incubations at elevated NO À 3 or sulfide concentrations were converted to in situ rates using the measured water column concentrations of NO À 3 and sulfide and the actual measured relations between NO À 3 and sulfide concentrations and denitrification rates. In situ denitrification ranged from 0.24 to 15.9 nM N 2 h À1 . Assuming that these rates were valid throughout the anoxic NO À 3 containing zone, depth integrated in situ denitrification rates of 0.06-2.11 mmol N m À2 d À1 were estimated. The thickness of this zone was generally 3-6 m, which is probably what can be maintained through regular turbulent mixing induced by internal waves at the oxic-anoxic interface. However, layers of up to 55 m thickness with low O 2 water (<10 lM) were observed which was probably the result of larger scale mixing. In such a layer nitrification may produce NO À 3 and once the O 2 has been depleted denitrification will follow resulting in enormous rates per unit area. Even with an active denitrification layer of 3-6 m thickness the pelagic denitrification per unit area clearly exceeded sediment denitrification rates elsewhere in the Baltic Sea. When extrapolated to the entire Baltic Proper (BP) denitrification in the water column was in the range of 132-547 kton N yr À1 and was thus at least as important as sediment denitrification which has recently been estimated to 191 kton N yr À1 . With a total external N-input of 773 kton N yr À1 it is clear that denitrification plays a significant role in the N-budget of the BP.

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“…Secondly, a loss of already formed ·NO could have attributed to the relatively small change in ·NO. Quantitative measurements of NO 2 − and NO 3 − were performed as an index of global nitric oxide (·NO) production [33,34]. Collected cell culture medium was incubated with nitrate reductase for 2 hours to convert NO 3 − to NO 2 − [3], followed by addition of Griess reagents.…”

Section: Discussionmentioning

confidence: 99%

“…Quantitative measurements of NO 2 − and NO 3 − were performed as an index of global nitric oxide (·NO) production essentially following methods described previously [34,35]. The level of ·NO produced by BAEC subjected to static (no flow) or oscillatory shear stress was measured by the Griess reaction [36].…”

Section: Measurement Of Nitrate/nitrite (Nomentioning

confidence: 99%

17β-Estradiol reverses shear-stress-mediated low density lipoprotein modifications

Hwang¹,

Rouhanizadeh²,

Hamilton³

et al. 2006

Free Radical Biology and Medicine

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Within arterial bifurcations or branching points, oscillatory shear stress (OSS) induces oxidative stress mainly via the NADPH oxidase system. It is unknown whether 17β-estradiol (E 2 ) can regulate OSS-mediated low density lipoprotein (LDL) modifications. Bovine aortic endothelial cells (BAECs) were pre-treated with E 2 at 5 nmol/L, followed by exposure to OSS (0 ± 3.0 dynes/ cm 2 sec and 60 cycles/min) in a flow system. E 2 decreased OSS-mediated NADPH oxidase mRNA expression, and E 2 -mediated ·NO production was mitigated by the ·NO synthase inhibitor L-NAME. The rates of O 2 −· production in response to OSS increased steadily as determined by superoxide dismutase-inhibited ferricytochrome c reduction; however, pre-treatment with E 2 decreased OSS-mediated O 2 −· production (n=4, P<0.05). In the presence of native LDL (50 μg/ mL), E 2 also significantly reversed OSS-mediated LDL oxidation as determined by high performance liquid chromatography. In the presence of O 2 −· donor, xanthine oxidase (XO), E 2 further reversed XO-induced LDL lipid peroxidation (n=3, P<0.001). Mass spectra were acquired in the m/z 400-1800 range, revealing XO-mediated LDL protein nitration involving tyrosine 2535 in the α-2 domains, whereas pre-treatment with E 2 reversed this observation, consistent with the changes in nitrotyrosine intensities by the dot blots. E 2 plays an indirect antioxidative role. In addition to up-regulation of eNOS and down-regulation of Nox4 expression, E 2 influences LDL modifications via lipid peroxidation and protein nitration.

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Nanogram nitrite and nitrate determination in environmental and biological materials by vanadium(III) reduction with chemiluminescence detection

Cited by 806 publications

References 7 publications

Structure and function of natural sulphide-oxidizing microbial mats under dynamic input of light and chemical energy

Structure and function of natural sulphide-oxidizing microbial mats under dynamic input of light and chemical energy

Denitrification in the water column of the central Baltic Sea

17β-Estradiol reverses shear-stress-mediated low density lipoprotein modifications

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