Dose Of Nitrate Research Articles

The effects of beetroot and nitrate supplementation on body composition: a GRADE-assessed systematic review and meta-analysis.

This systematic review and meta-analysis aimed to investigate the effects of beetroot (BR) or nitrate supplements on body composition indices. A systematic search was conducted for randomised controlled trials (RCT) published up to August 2022 among online databases including Scopus, PubMed/Medline, Web of Science and Embase. Meta-analyses were carried out using a random-effects model. The I2 index was used to assess the heterogeneity of RCT. A total of twelve RCT met the inclusion criteria for this meta-analysis. The pooled effect size of included studies indicated that BR or nitrate supplementation did not change body weight (weighted mean differences (WMD): -0·14 kg, 95 % CI -1·22, 1·51; P = 0·836; I2 = 0 %), BMI (WMD: -0·07 kg/m2, 95 % CI -0·19,0·03; P = 0·174, I2 = 0 %), fat mass (WMD: -0·26 kg, 95 % CI -1·51, 0·98; P = 0·677, I2 = 0 %), waist circumference (WMD: -0·28 cm, 95 % CI -2·30, 1·74; P = 0·786, I2 = 0 %), body fat percentage (WMD: 0·18 %, 95 % CI -0·62, 0·99; P = 0·651, I2 = 0 %), fat-free mass (WMD: 0·31 kg, 95 % CI -0·31, 1·94; P = 0·703, I2 = 0 %) and waist-to-hip ratio (WMD: 0, 95 % CI -0·01, 0·02; P = 0·676, I2 = 0 %). Subgroup analyses based on trial duration, BR or nitrate dose, study design, baseline BMI and athletic status (athlete v. non-athlete) demonstrated similar results. Certainty of evidence across outcomes ranged from low to moderate. This meta-analysis study suggests that BR or nitrate supplements cannot efficiently ameliorate body composition indices regardless of supplement dosage, trial duration and athletic status.

Antioxidant Capacity, Nitrite and Nitrate Content in Beetroot-Based Dietary Supplements.

Due to the high content of bioactive substances, beetroot and its preserves might be a valuable constituent of a diet. Research into the antioxidant capacity and content of nitrate (III) and (V) in beetroot-based dietary supplements (DSs) worldwide is limited. The Folin-Ciocalteu method, CUPRAC, DPPH, and Griess methods were used to determine total antioxidant capacity, total phenolic content, nitrites, and nitrates content in fifty DSs and twenty beetroot samples. Moreover, the safety of products was evaluated because of the concentration of nitrites, nitrates, and the correctness of labelling. The research showed that a serving of fresh beetroot provides significantly more antioxidants, nitrites, and nitrates than most daily portions of DSs. Product P9 provided the highest dose of nitrates (169 mg/daily dose). However, in most cases, the consumption of DSs would be associated with a low health value. The acceptable daily intake was not exceeded in the cases of nitrites (0.0015-0.55%) and nitrates (0.056-48%), assuming that the supplementation followed the manufacturer's recommendation. According to European and Polish regulations, 64% of the products tested did not meet all the requirements for labelling food packaging. The findings point to the need for tighter regulation of DSs, as their consumption might be dangerous.

Nitrate-rich beet juice intake on cardiovascular performance in response to exercise in postmenopausal women with arterial hypertension: study protocol for a randomized controlled trial

BackgroundThere is no evidence of the use of beetroot juice with a previously recommended dose of nitrate (NO3) (> 300 mg) on the cardiovascular performance during and recovery following exercise in postmenopausal women with systemic arterial hypertension (SAH).MethodsWe will investigate the effects of beetroot juice rich in NO3 acutely (800 mg) and during a week with daily doses (400 mg) on blood pressure, heart rate (HR), cardiac autonomic control, endothelial function, inflammatory, hormonal, and stress biomarkers oxidative stress and enzymes involved in nitric oxide synthesis and mitochondrial regulation, under resting conditions, as well as mediated by submaximal aerobic exercise sessions. Through a randomized, crossover, triple-blind, placebo-controlled clinical trial, 25 physically inactive women with SAH will undergo an acute and 1-week trial, each with two intervention protocols: (1) placebo and (2) beetroot, in which will ingest beet juice with or without NO3 in its composition with a 7-day washout interval. On collection days, exercise will be performed on a treadmill for 40 min at a speed corresponding to 65–70% of VO2peak. The collection of variables (cardiovascular, autonomic, and blood samples for molecular analyses) of the study will take place at rest (135 min after ingestion of the intervention), during exercise (40 min), and in the effort recovery stage (during 60 min) based on previously validated protocols. The collections were arranged so that the measurement of one variable does not interfere with the other and that they have adequate intervals between them.DiscussionThe results of this research may help in the real understanding of the nutritional compounds capable of generating safety to the cardiovascular system during physical exercise, especially for women who are aging and who have cardiovascular limitations (e.g., arterial hypertension) to perform physical exercise. Therefore, our results will be able to help specific nutritional recommendations to optimize cardiovascular health.Trial registrationClinicalTrials.gov NCT05384340. Registered on May 20, 2022.

Treatment Outcomes of the Acute Coronary Syndrome Among Patients Attending St. Paul Hospital.

Acute coronary syndrome (ACS) patients need intense therapy and diagnostic evaluation for improved treatment. In Ethiopia, where patient deaths and hospital stays are rising, the ACS treatment is thought to be not very effective. A retrospective cross-sectional study was conducted at St. Paul Hospital. The data were collected from patients medical records using a structured data abstraction checklist from 2018 to 2020. The data was entered, analyzed, and interpreted using SPSS version 24 software. Of 157 ACS patients, 69 (43.9%) had a STEMI diagnosis. Age was 63.69 years on average (SD: 8.23). The typical amount of time between the onsets of ACS symptoms to hospital presentation was 79.3 hours (3.3 days). For 104 (66.2%) patients, hypertension was the main risk factor for the development of ACS. Killip class III and IV patients made up about 3.8% of the ACS patients at St. Paul hospital. An EF of less than 40% was present in 36.3% of patients. Loading doses of aspirin (90.4%), anticoagulants (14%), beta-blockers (82.8%), statins (86%), clopidogrel (7.6%), and nitrates (2.5%) are among the medications taken inside hospitals. Of 157 ACS patients, 6 (3.8%) patients with medical records examined died while receiving treatment in the hospital, while 151 (96.2%) patients were discharged alive. STEMI was the most common diagnosis for ACS patients at St. Paul Hospital. The two main hospital events for these patients were CHF and cardiogenic shock.

Ultrasensitive detection of thiram based on surface-enhanced Raman scattering via Au@Ag@Ag core/shell/shell bimetallic nanorods.

We developed a highly sensitive and stable SERS-active substrate of Au@Ag@Ag core/shell/shell nanorods, formed by encapsulating Au nanorods (Au NRs) into a bilayer silver shell with Raman reporter molecules (4-mercaptobenzoic acid (4-MBA) and thiram) in the shell-shell gap. The core/shell/shell nanostructures demonstrated a high SERS enhancement and easy assembly. The important role of the bilayer silver shell in boosting the SERS intensity and detection sensitivity was revealed by comparing the performances of the Au@Ag@4-MBA@Ag NRs, Au@Ag@4-MBA NRs, and Au@4-MBA NRs. The obtained Au@Ag@4-MBA@Ag NRs exhibited a significantly promoted SERS intensity, which could reach around 2.6 times and 240 times that of the Au@Ag@4-MBA NRs and Au@4-MBA NRs, where the enhancement factor was found to be strongly correlated with the shell thickness. The controllable plasma properties and SERS effect of the Au@Ag@4-MBA@Ag NRs could be optimized by adjusting the dose of silver nitrate. The SERS substrate comprising core/shell/shell nanorods was highly reproducible and stable (retaining 83% SERS intensity after one month). Moreover, the highly sensitive detection of the pesticide thiram with a detection limit as low as 1.74 × 10-9 M was achieved by taking advantage of the great SERS response of the core/shell/shell nanostructures, which was 1-2 orders of magnitude lower than for other SERS substrates. The developed SERS substrate could be readily extended to embed other target analytes into the core/shell/shell nanostructure for novel and sensitive detection. This study could enable fresh approaches toward next-generation ultrasensitive analyte detection.

Effect of Different Ammonium Nitrate Levels on the Performance of Cool-Climate Grass Species Grown in Çanakkale Conditions

This study was conducted to investigate effects of different levels of ammonium nitrate (33% N) dose (0, 50 and 100 g m-2) on morphological and quality traits of 3 different commonly cultivated turfgrass species (Lolium perenne ‘TOPGUN’, Festuca rubra ‘SERGEİ’ and Poa pratensis ‘AVALANCHE’) which are widely preferred in grass mixtures prepared for green areas in Çanakkale (Turkey). Fertilization treatments had positive effects on morphological parameters, except for germination power and germination rate parameters. In terms of landscape related aesthetic quality and growth percentage, 50 g m-2 and fertilization was found to be more suitable for Lolium perenne, while 100 g m-2 fertilization provided better performance for Festuca rubra. The 50 and 100 g m-2 fertilization rates yielded similar results for Poa pratensis in terms of general grass quality. It was observed that 50 g m-2 ammonium nitrate had a positive effect on root area and volume compared to other applications. In this application (50 g m-2 ammonium nitrate), the positive features of the root (high root area and volume) are the features that can prevent the grass plant from breaking off from the soil.

Effects of different combinations of growth regulators on the in vitro growth parameters of Poncirus trifoliata L. (Raf.)

In this study, an in vitro propagation protocol of Poncirus trifoliata L. (Raf.) rootstock, which is one of the main rootstocks used in citrus, was created. Monocular node parts of the plant, which is the source of explant, were cultured in MS nutrient media containing BAP at dissmilar concentrations (0.5-1.0-2.0 mg/l). Afterward, it was observed that shoot appearance and tillering were achieved in the node explants cultured in MS nutrient medium comprising 1.0 mg/l BAP. The shoots were removed to a new culture in MS nutrient media containing NAA and IBA for rooting. While 30% rooting was achieved in the rooting medium, 62% of the rooted plantlets were acclimated to external conditions. 2 mg/l BAP and 2 mg/l silver nitrate (AgNO3) doses were supplied to the MS medium. The results of this study were obtained and a compound was found to the yellowing and leaf fall problem. As a result, in vitro propagation of Poncirus trifoliata, which is among the important citrus rootstocks, was tried, and its rooting ability was investigated in different nutrient media concentrations after shoots were obtained from different explants.

Effects of different doses of ammonium nitrate applications on nutrient content in some types of grass: nutritional support

This study was conducted under ecological conditions of Çanakkale (Turkey) province to investigate the effects of different ammonium nitrate (33% N) dose (0, 50 and 100 g m-2) on nitrogen, protein, macro-micro nutrient analyses of 3 different commonly cultivated grass varieties (Lolium perenne TOPGUN, Festuca rubra SERGEİ and Poa pratensis AVALANCHE). Plant nitrogen-protein analyses (nitrogen, protein) were determined besides plant macro-micro nutrient analyses (phosphorus, potassium, calcium, magnesium, ıron, manganese) of grass plants were determined. In the study, in addition to having information about the mineral content of grass species removed from the soil, the potential of the cuttings, which are formed when the grass plants are mowed, when used as green manure or compost has been determined.Fertilizer treatments increased nitrogen, phosphorus, potassium and protein contents of grass clippings and decreased calcium, iron, magnesium and manganese contents. In general, it was determined that the application of ammonium nitrate (33% N) at a dose of 100 g m-2 increased the nitrogen, protein, phosphorus and potassium amounts of plants compared to the application of ammonium nitrate (33% N) at a dose of 50 g m-2. Especially nitrogen phosphorus potassium fertilizers are among the fertilizers applied in intensive amounts in the agricultural sector. It is seen that nitrogen-containing ammonium nitrate fertilizer applied to grass plants increases the nitrogen content of grass plants. When the results of the study were examined, important information was obtained about how the fertilization density affects the nutrient content of the grass plants according to the species.

The reproductive toxicity of yttrium nitrate in a two-generation study in Sprague-Dawley rats

ObjectiveTo evaluate the effects of yttrium nitrate on the development of the parent, offspring and third generation of Sprague-Dawley (SD) rats by using a two-generation reproductive toxicity test. MethodsThe SD rats were randomly divided into 0 mg/kg group, 10.0 mg/kg group, 30.0 mg/kg group and 90.0 mg/kg group according to the different doses of yttrium nitrate administration. The reproductive toxicity of parent, offspring and third generation SD rats were compared. ResultsThe weight gains of F1a female rats and F2a female rats in the low-dose groups were significantly lower than those of the control groups (p < 0.05), the weight gains of F1a male rats in the medium-dose and high-dose groups were significantly lower than those of the control groups (p < 0.05), and the weight gains of F2a male rats in the low-dose, medium-dose and high-dose groups were significantly lower than those of the control groups (p < 0.05). In F0 male rats, the absolute weight and relative weight of the liver in the low-dose, middle-dose, and high-dose groups were significantly lower than those of the control group (p < 0.05). In F1b male rats, the absolute and relative weights of the liver in the medium-dose and high-dose groups were significantly lower than those of the control group (p < 0.05). In F2b male rats, the absolute and relative weights of the liver and spleen of the medium-dose and high-dose groups were significantly lower than those of the control group (p < 0.05). In F2a female rats, the absolute weight and relative weight of oviduct in the high-dose group were significantly lower than those in the control group (p < 0.05). The absolute and relative weights of lung, spleen, brain and uterus of F2b female rats in the high-dose group were higher than those of the control group (p < 0.05). But the pathological test results showed no hepatotoxicity. There was no statistically significant difference in sperm count and sperm motility between male rats in the yttrium nitrate administration groups and the control group (p > 0.05). There was no significant correlation between F0, F1a, F1b, F2a, F2b SD rats' reproductive organ lesions and the dose of yttrium nitrate. ConclusionYttrium nitrate at a dose of 90 mg/kg has no reproductive toxicity to two generations of SD rats, but 30.0 mg/kg dose of yttrium nitrate is toxic to the liver weight of male two generations of SD rats, but no hepatotoxicity.

Combined effect of acute salt and nitrogen stress on the physiology of lichen symbiotic partners

Nitrogen pollution and excessive salinity are commonly regarded as one of the major environmental concerns in recent decades in many urban environments. Although in urban areas lichens are exposed to both salt and nitrogen stress, no studies have been conducted to date on the simultaneous impact and interaction of these factors on lichen physiology. The aim was to determine the effect of various combinations of NaCl and NH4NO3 doses on the physiology of epigeic lichen Cladonia rei. We also aimed to compare the response of lichens collected from polluted and unpolluted sites to verify whether lichens exposed to different levels of environmental stress in their native environment will react differently. The combined salt-nitrogen treatment caused significant disturbances in the integrity of cell membranes and chlorophyll fluorescence parameters. The most detrimental effect concerned the loss of cell membrane integrity, which suggests that this parameter can serve as a relevant indicator of acute salt-nitrogen stress incidents. Salt stress decreased the photosynthetic efficiency 1 h after exposure, but after 72 h, the FV/FM returned to the level characteristic of healthy lichens in experimental groups without and with small doses of ammonium nitrate. In contrast, recovery was not possible in combination with high nitrogen doses. This indicates that exposure to short-term salt stress in a nitrogen-poor environment only causes a temporary reduction in photosynthetic efficiency, but in urban eutrophic environments may have more serious consequences. The weakened physiological condition of the mycobiont manifested by an increased level of cell membrane damage and a persistent decrease in the photosynthetic efficiency of the photobiont in lichens growing along the roads may indicate an excess of nitrogen in the environment, enhanced by the effect of salt. Lichens collected from a heavy-metal-polluted habitat responded more strongly than those from an unpolluted habitat suggesting that in lichens previously affected by certain harmful factors, exposure to another stress factor may lead to greater disturbances. This is of particular importance for lichens inhabiting the vicinity of roads, since they are also under the influence of other pollutants emitted by road traffic.

In vitro digestion of nitrite and nitrate preserved fermented sausages - New understandings of nitroso-compounds' chemical reactivity in the digestive tract.

In vitro digestions of dry-cured sausages formulated with four different rates of added sodium nitrite and sodium nitrate (NaNO2 / NaNO3, in ppm: 0/0; 80/80; 120/120; 0/200) were performed with a dynamic gastrointestinal digester (DIDGI®). The chemical reactivity of the potentially toxic nitroso-compounds (NOCs), oxidation reactions products and different iron types were evaluated over time. No nitrite nor nitrate dose effect was observed on NOCs' chemical reactivity. Nitrosothiols were scarce, and nitrosylheme was destabilized for every conditions, possibly leading to free iron release in the digestive tract. Total noN-volatile N-nitrosamines concentrations increased in the gastric compartment while residual nitrites and nitrates remained stable. The minimal rate of 80/80ppm nitrite/nitrate was enough to protect against lipid oxidation in the digestive tract. The present results provide new insights into the digestive chemistry of dry sausages, and into new reasonable arguments to reduce the load of additives in formulations.

The Composition of the Organic Matter Fractions of Loamy Sand after Long-Term FYM Application without Liming

The key to soil organic matter management is understanding the transformation processes of fresh organic matter to permanent humus that control soil organic carbon dynamics. This paper presents the results of the effect of long-term soil fertilization with increasing doses of (manure) FYM and ammonium nitrate on the composition of humus compounds not limed of loamy sand. The study showed that both crop rotation and manure fertilization significantly affected organic matter fractions and humus humification index. The soil in crop rotation B (with enriching effect) accumulated significantly larger amounts of soil organic carbon in 0–30 cm layer despite a lower soil pH, but had lower soil organic quality compared to the soil in crop rotation A (with depleting effect). In both rotations, FYM was applied once per 4-year rotation at a dose of 40 t·ha−1 which improved the soil organic carbon content. Depleting crop rotation (A) showed no increase in soil accumulation of humins fractions (H), while the “enriching” crop rotation (B) had such a tendency. Mineral nitrogen fertilization significantly affected the composition of the humic acids fraction. The soil in crop rotation B was characterized by a significantly higher content of fulvic acid (FA) and lower of humins (H) carbon fraction. The large input of organic matter into the soil under lower content pH conditions may hinder its transformation into permanent humus. Changes in the humification index were the consequence of changes in the carbon content of humic and fulvic acids, under the influence of plant selection in crop rotation and manure fertilization. According to the criterion of this parameter, soil in crop rotation A and soil fertilized with manure had lower loss of the more labile FA fraction (lower value of humification index—1.48).

Assessment of limited downstream nitrate dosing for sulphide control in pressure sewers: case study in Germany

Abstract Odour release from sewer systems is an established environmental issue affecting many cities worldwide. A key indicator for the severity of the odour problem in sewer systems is linked to the amount of sulphide produced and released as hydrogen sulphide (H2S) into the urban environment. For this reason, an in-depth understanding of the biochemical processes of sulphurous compounds in sewer systems is an underlying base point for designing and implementing odour control strategies for sewer systems. This contribution focuses on a field study on the monitoring and assessing chemical dosing on a 9.0 km pressure sewer in Ueckermünde, Germany. Online H2S measurements indicated a daily reoccurrence of sulphide spikes between 4:00 and 8:00 am during the monitoring period. During this period, the wastewater slugs exiting the sewer section remained in the dosed section of the pipe the longest, and regeneration of sulphide production began after 3 hours, causing the hydrogen sulphide spikes. The proposed dosing strategy provides a cost-effective and efficient solution for sulphide build-up in long pressure sewers that connect rural areas to centralised wastewater collection and treatment systems.

Acute Effects of Inorganic Nitrate Intake on Brachial and Femoral Flow-Mediated Vasodilation, and on Carotid Artery Reactivity Responses: Results of a Randomized, Double-Blinded, Placebo-Controlled Cross-Over Study in Abdominally Obese Men.

Most trials on the effects of inorganic nitrate intake have focused on only one specific aspect of the endothelial cell response to a stimulus, thereby possibly missing other important effects. The aim of the present randomized, double-blinded, placebo-controlled cross-over study was therefore to investigate in eighteen healthy abdominally obese men (18–60 years, waist circumference ≥ 102 cm) acute effects of potassium nitrate on brachial and femoral flow-mediated vasodilation (FMD), and on carotid artery reactivity (CAR) to a cold pressure test. Participants received in random order a drink providing 10 mmol potassium nitrate (i.e., 625 mg of nitrate) or an iso-molar placebo drink with potassium chloride. Fasted and 4 h post-drink FMD and blood pressure measurements were performed. CAR responses were assessed at 4 h. Circulating nitrate plus nitrite concentration increased following nitrate intake (p = 0.003). Compared with placebo, potassium nitrate did not affect brachial (mean [95% confidence interval]: −0.2% [−2.5, 2.1], p = 0.86) and femoral FMD responses (−0.6% [−3.0; 1.7], p = 0.54). CAR responses were also not different (−0.8% [−2.5, 0.9], p = 0.32). Finally, changes in blood pressure and heart rate did not differ. No adverse events were observed. In conclusion, this trial did not provide evidence for effects of a single dose of inorganic nitrate on 4 h vascular endothelial function in abdominally obese men.

Sulfide Generation in Force Mains and Its Control Using Nitrate Dosing

Sulfide generation rates in the force mains of four pump stations in Edmonton, Alberta, Canada, were evaluated in the field, and a continuous nitrate dosing was applied in the pump wet well of the Big Lake pump station to investigate its effectiveness on sulfide control. The sulfide production rates at these force mains were estimated to be 0.08–0.15 g/m2 h under 20°C, which could be modeled by using the 1/2-order biofilm kinetics of dissolved chemical oxygen demand (DCOD). The modeled rate constant a was obtained at around 0.006 using the field monitoring data. It was found that 20 mg/L sulfide was formed in the force main of the Big Lake pump station, which resulted in 400–500 parts per million (ppm) H2S gas in the discharge manhole. It was found that a nitrate dosing concentration of 85 mg/L could completely suppress the sulfide generation in the force main. A constant dosing rate resulted in nitrate overdosage at midnight and underdosage in peak hours. Injecting nitrate in the wet well led to a large portion of nitrate consumption where a heterotrophic denitrification process happened. The appropriate dosing location for this dosing strategy is at the beginning of force main instead of the wet well. The corresponding dosing rate is a flow-paced dosing rate instead of a constant dosing rate. A more cost-effective dosing strategy is to add the nitrate at downstream section of the force main where sulfide generated upstream could be removed in the presence of nitrate when passing downstream. This dosing strategy could significantly reduce the nitrate demand.

Seeder for Different Depths of Grain Sowing and Mineral Fertilizers Application

The article presents the main results of a three-year research on the use of a seeder with openers for different depths of grain sowing and mineral fertilizers application.Research purpose To compare SKP-2.1 seeder equipped with experimental openers and the serially produced one and to determine the yield and quality indicators of spring soft wheat grain, depending on the sowing method and the rate of nitrogen mineral fertilizers application.Materials and methods A comparative field agrotechnical experiment was carried out to compare the indicators of field germination, yield by variants and the quality of grain obtained in different variants of the experiment. The experiment was carried out on Omskaya-36 soft spring wheat. The sowing performed by SKP-2.1 serially produced seeder-cultivator was taken as control. The experimental plots were sown with the same seeder but equipped with combined coulters, which are lancet paws that ensure the placement of granular mineral fertilizers and seeds in soil horizons of different depths.Results and discussion According to the three-year research, the maximum economic effect was obtained at the rate of ammonium nitrate application of 150 kg/ha. As a result, the yield increased by 0.44 t/ha, the cost of additional production accounted for 6740 rub/ha. A slight decrease in the economic effect was revealed with an increase in the rate of fertilizer application. It was determined that the maximum yield and the best grain quality characteristics both in the control sowing options and in the experimental ones were obtained with the application of ammonium nitrate a rate of 150 and 200 kg/ha.Conclusions It was established that the use of a seeder for different-depth grain sowing and mineral fertilizers application, depending on the spring weather conditions and the ammonium nitrate dose, provides an increase in field germination by 11-18%; the average annual increase in grain yield accounted for 16.3%. The gluten content proved to increase from 24.6 (control) to 29.8 percent.

Online Control of Lemna minor L. Phytoremediation: Using pH to Minimize the Nitrogen Outlet Concentration.

Phytoremediation technologies are employed worldwide to remove nutrient pollutants from agricultural and industrial wastewater. Unlike in algae-based nutrient removal, control methodologies for plant-based remediation have not been standardized. Control systems that guarantee consistently low outlet concentrations of nitrogen and phosphorous often use expensive analytical instruments and are therefore rarely viable. In this study, pH measurement was used as the sole input to control the nitrate outlet concentration in a continuously operated Lemna minor (lesser duckweed) phytoremediation tank. When grown in 20 L batches of modified Hoagland’s solution, it was found that a constant ratio exists between the amount of nitrate removed and the amount of acid dosed (required for pH control), which was equal to 1.25 mol N·(mol H+). The nitrate uptake rates were determined by standard spetrophotometric method. At critically low nitrate concentrations, this ratio reduced slightly to 1.08 mol N·(mol H+). Assuming a constant nitrogen content, the biomass growth rate could be predicted based on the acid dosing rate. A proportional-integral controller was used to maintain pH on 6.5 in a semi-continuously operated tank covered by L. minor. A nitrogen control strategy was developed which exploited this relationship between nitrate uptake and dosing and successfully removed upwards of 80% of the fed nitrogen from synthetic wastewater while a constant biomass layer was maintained. This study presents a clear illustration of how advanced chemical engineering control principles can be applied in phytoremediation processes.

In vitro establishment and multiplication of Aechmea fasciata (Lindl.) Baker, a bromeliad of commercial interest

Objective: To develop a protocol for the aseptic in vitro establishment and multiplication of Aechmea fasciata (Lindl.) Baker. Design/Methodology/Approach: Different concentrations of NaClO (2, 3, 4, and 5%) were assessed for the aseptic establishment of A. fasciata. During the shoot induction stage, the three following treatments were tested: T1 = 6-benzyladenine + naphthalene-1-acetic acid (BA + ANA; 5 + 2 mg L-1); T2 = zeatin + 2,4-dichlorophenoxyacetic acid (Zea + 2,4-D; 5 + 2 mg L-1); and T3 = control with no plant growth regulators. During the shoot multiplication stage, three more treatments were assessed: T1 = Zea + 2,4-D (2.5 + 1 mg L-1); T2 = Zea + 2,4-D (5 + 2 mg L-1); and T3 = Zea + 2,4-D + gibberellic acid (AG3) (2.5 + 1 + 3.5 mg L-1). To assess the number of cellular events, different nitrate concentrations were tested in the medium (18.8, 39.4, and 60 mM NO3-). Finally, during the shoot regeneration stage, nine treatments derived from the combination of three concentrations of kinetin (KIN: 0, 0.1, and 0.5 mg L-1) and of indole-3-acetic acid (AIA: 0, 0.3, and 0.4) were assessed. Completely randomized designs were used in each stage. Duncan’s test (p ≤ 0.05) was used to compare the means during the shoot induction and multiplication stages. A regression analysis was carried out to study the aseptic establishment and a non-parametric test (Kruskal-Wallis) was made to assess the “amount of microshoots during regeneration” variable. Results: A. fasciata aseptic explants with 4% NaClO were established. Shoot induction was most effective with the BA + ANA (5 + 2 mg L-1) treatment. The highest callus production was reported with the Zea + 2,4-D (5 + 2 mg L-1) treatment. The largest number of microshoots was obtained with high nitrate doses. Meanwhile, the most successful regeneration was achieved with the 0.1 mg KIN L-1 and 0.4 mg AIA L-1 treatment. Study Limitations/Implications: The application of Zea and 2,4-D during multiplication induced callus formation. Findings/Conclusions: Apical bud explants in an MS medium with BA and ANA present organogenesis. The use of Zea and 2,4-D forms calluses in the already established in vitro shoots, which regenerate with the use of KIN and AIA. Better microshoot coloring and development were achieved with MS salts, which have a medium nitrate content.

Tolerance of Rodents to an Intravenous Bolus Injection of Sodium Nitrate in a High Concentration.

Simple SummaryNitrate is found in many foods and is a common metabolite that is supplied mostly through the diet. Recently, we have found that an analog of this compound, labeled with the stable isotope (non-radioactive) nitrogen-15, is a potentially useful contrast agent for magnetic resonance imaging (MRI), as it does not include a metal component as most other MRI contrast agents. This analog was previously shown with a very high magnetic resonance signal, which is relatively long-lasting, when combined with the new adjunct technology to MRI called hyperpolarization. Prior to serving as a contrast agent for MRI in patients, this agent needs to be tested and validated in small animals. As a prerequisite to such studies, one must ensure that the injection of the naturally abundant agent (not labeled with any isotopes) will be tolerated by the animals. The purpose of the current study was to evaluate the tolerance to an intravenous injection of sodium nitrate in rats and mice, as MRI contrast agents are routinely administered in this way. We have found that a high dose of sodium nitrate can be safely injected into rats and mice. This result opens the way for preclinical MRI studies with sodium nitrate.Nitrate, the inorganic anion NO3−, is found in many foods and is an endogenous mammalian metabolite, which is supplied mostly through the diet. Although much is known about the safety of sodium nitrate when given per os, methodological safety data on intravenous bolus injection of sodium nitrate to rodents are lacking. Recently, we have proposed a new use for nitrate, as a contrast agent for magnetic resonance imaging that will be metal free and leave no traces in the body and the environment further to the imaging examination. It was shown that a stable isotope-labelled analog of this ion (15NO3−), in a sodium nitrate solution form and hyperpolarized state, produces a high magnetic resonance signal with prolonged visibility. Therefore, sodium nitrate was targeted for further preclinical development in this context. In the absence of methodological safety data on the potential effects of a high concentration sodium nitrate bolus intravenous injection into rodents, we carried out such an investigation in mice and rats (n = 12 of each, 6 males and 6 females in each group, altogether 24 animals). We show here that an intravenous bolus administration of sodium nitrate at a concentration of 150 mM and a dose of 51 mg/Kg does not lead to adverse effects in mice and rats. This is the first investigation of the tolerance of rodents to an intravenous injection of sodium nitrate.

Impact of nitrate addition on the resistome and mobilome from a full-scale sewer

Oxidative chemicals, such as nitrate, are periodically added to sewer systems to mitigate sulfide production and its accumulation but data are lacking on how these treatments affect sewage microbiota and alter their gene expression and mobilization. The present study investigated such effects on the biofilm of a full-scale sewer collected at two different locations, namely a pumping station and at the inlet of an urban wastewater treatment plant (WWTP), before and 15 days after nitrate dosage using a combination of culture-dependent and -independent approaches. Nitrate dosing resulted ineffective on the concentration of antibiotic-resistant Escherichia coli (AR-EC) in biofilms but greatly affected the composition of biofilm bacterial communities and the associated resistome and mobilome, especially at the pumping station where nitrate was dosed. Such responses consisted of a clear reduction on strict anaerobes; an almost twofold increase on the expression of recA gene (stress-response marker); and a significant increase on the relative abundance of most antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs). In turn, the effects of nitrate dosing at the WWTP inlet were barely visible, suggesting that they vanished into the distance from the pumping site (2.4 km). Remarkably, however, the relative abundance of both resistance and mobilization gene biomarkers at the inlet of the studied WWTP clearly oversized that at the pumping station confirming that these facilities are sinks where these resistance determinants accumulate and propagate. Considering the abundance of resistant bacteria and genes in urban sewage, the effects of dosing chemicals should be carefully assessed to lessen the load of such biological pollutants into WWTPs.