Dose Of Nitrate Research Articles

Method of intensification of digestive and intermediary metabolism in meat quails during denitrification

Sorbents are characterized by synergistic action with many biologically active compounds, including antioxidants that neutralize free radicals in the body, prevent membrane damage, and preserve the youth of the cells of organs and tissues of poultry. The purpose of the study was to determine the eff ect of the sorbent Mikosorb®A Plus and the antioxidant Hadox on the parameters of digestive and intermediary metabolism in meat quails when they are added to compound feed with a subtoxic dose of nitrates. It was found that in order to improve the digestive and intermediary metabolism in meat quails, the composition of their compound feed should include the drugs of the sorbent Mikosorb®A Plus at the dose of 1000 g/t and the antioxidant Hadox at the dose of 150 g/t of compound feed. These drugs allowed to increase signifi cantly (p < 0.05) the coeffi cients of dry matter digestibility by 3.43 abs.%, organic matter by 3.33 abs.%, crude protein by 3.55 abs.%, crude fi ber by 3.48 abs.% and nitrogen-free extractive substances by 3.57 abs.% in the quails of the 3rd experimental group compared to the control group. This also allowed to increase the number of erythrocytes in the blood of quails of the 3rd experimental group by 0.56×1012/l (p < 0.05), hemoglobin by 7.0 g/l (p < 0.05) with a simultaneous decrease in methemoglobin by 1.40 % (p < 0.05) compared to the control analogues. In the quails of the 3rd experimental group, the concentration of total protein in the blood serum was higher by 5.20 g/l (p < 0.05) with a simultaneous decrease in the content of nitrates by 1.63 times (p < 0.05) and nitrites by 2.47 times (p < 0.05) compared to the quails of the control group. Joint feeding of the sorbent and antioxidant inhibited lipid peroxidation processes and had a stimulating eff ect on the antioxidant defense mechanism in the quail body. At the same time, the quails of the 3rd experimental group had a lower proportion of conjugated dienes by 40.54 % and malondialdehyde by 28.72 % compared to the control group.

Dose-dependent long-term effects of nitrate on lipid profile in male rats

Background. This study aims to investigate the long-term effects of different doses of nitrate on the lipid profile in male rats. Methods. Male Wistar rats (n = 60) were assigned to 6 groups (n = 10 per group). The control group received drinking water, and 5 treatment groups received nitrate at doses of 50, 100, 150, 250, and 500 mg/L for 6 months. Nitric oxide (NO) metabolite levels (NOx) were determined at months 0 and 6. Lipid profile [cholesterol, triglyceride (TG), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL)] in the serum was measured at months 0, 3, and 6. Results. Nitrate administration for 6 months (at doses of 50, 100, 150, 250, and 500 mg/L) could increase serum NOX levels by 29.5% (P = 0.0115), 39.6% (P = 0.0002), 65.2% (P < 0.0001), 91.4% (P < 0.0001), and 181.6% (P < 0.0001), respectively. Nitrate administration for 6 months (at doses of 50, 100, and 150 mg/L) decreased serum TG [7.8% (P = 0.0508), 7.4% (P = 0.0654), and 8.3% (P = 0.0331)] and cholesterol [12.7% (P = 0.0066), 15.2% (P = 0.0009), and 15.2% (P = 0.0009)] levels. In addition, it increased serum HDL at doses of 50, 100, and 250 mg/L [24.4% (P = 0.0005), 13.9% (P= 0.0910), and 17.5% (P = 0.0172)], while it had no significant effect on serum LDL levels in comparison to the control group. Conclusion. Long-term nitrate administration at low doses (50‒150 mg/L) prevented dyslipidemia (improved lipid profile) in male rats. These beneficial effects of nitrate can be mainly due to increased serum levels of NO metabolites. Practical Implications. These findings imply that long-term nitrate administration at low doses, achieved by consuming a diet containing vegetables, can potentially be utilized to manage dyslipidemia.

Effects of Dietary Nitrate Supplementation on Physical Performance and Muscle Strength in Older People—A Systematic Review

ABSTRACTBackgroundSarcopenia, the loss of muscle strength and mass with age, is a major cause of morbidity for older people. Dietary nitrate supplementation has been proposed as an intervention to improve skeletal muscle function via action as nitric oxide (NO) donors. However, the effect of nitrate supplementation on physical performance and muscle strength in older people is unclear. We aimed to systematically review evidence on whether dietary nitrate supplementation improves markers of muscle strength, muscle mass and physical performance in older people.MethodsWe conducted a systematic review of randomised controlled trials according to a prespecified protocol by two reviewers. We included interventional studies using dietary nitrate supplementation, mean participant age of >60 years, with or without muscle weakness. Outcomes of interest were physical performance, muscle strength and muscle mass. Risk of bias was assessed using a modified version of the Cochrane Risk of Bias tool. Results were grouped by intervention and outcome measures and were described by narrative synthesis.ResultsTwenty‐eight studies were included, with a size range of 8–72 participants. Intervention duration ranged from a single dose to 12 weeks. Seven studies were in healthy older people. Most studies had a high or unclear risk of bias; three had a low risk of bias. One‐hundred‐two outcomes were reported; 67 were related to physical performance, and 35 were related to muscle strength. No included study measured muscle mass. Thirty‐three outcomes showed significant improvement, two showed significant worsening and 67 showed no statistically significant difference. Meta‐analysis was not possible due to data heterogeneity. Subgroup analyses for different doses of nitrate (above or below 10 mmol nitrate per day), duration of treatment or specific commonly measured outcomes did not indicate any subgroup more likely to show positive results. The proportion of positive outcomes was similar in studies using beetroot extract, nitrate alone or exercise as a co‐intervention.ConclusionsCurrent evidence is insufficient to decide if dietary nitrate supplementation improves skeletal muscle function in older people. Future studies should be longer, larger and target older people with sarcopenia or frailty.

Optimizing Sugarcane Clonal Propagation In Vitro by Using Calcium Ammonium Nitrate and Ammonium Sulfate.

To replace explosive nitrate-based chemicals in MS medium, this study developed a new, safer, and more cost-effective method using fertilizer-grade calcium ammonium nitrate and ammonium sulfate. This approach replaces ammonium nitrate and potassium nitrate, ensuring both safety and cost efficiency for sugarcane propagation. Six local sugarcane varieties-Zhongtang1 (ZT1), Zhongtang3 (ZT3), Zhongtang6 (ZT6), Guitang42 (GT42), Guitang44 (GT44), and Guiliu 07150 (GT07150)-were used. In the control group (Ck), nitrate ions (NO3-) were 39.28 mM, and ammonium ions (NH4+) were 20.49 mM, with a 2:1 ratio. In the treatment groups, the concentrations of nitrate ions (NO3-) and ammonium ions (NH4+) included treatment 1 (19.69 mM NO3- and 10.3 mM NH4+), treatment 2 (29.54 mM and 15.44 mM), treatment 3 (39.38 mM and 20.59 mM), treatment 4 (49.225 mM and 25.74 mM), treatment 5 (59.07 mM and 30.89 mM), and treatment 6 (68.915 mM and 36.03 mM), respectively, all with the same 2:1 ratio. Fifty bottles per treatment, with three replicates, were used for each sugarcane plantlets treatment. After five subcultures, the optimal ratio was determined by assessing morphological and physiological parameters, nitrogen levels, and SOD enzyme activity. The results indicated that treatment 3 (39.38 mM and 20.59 mM) and treatment 4 (49.225 mM and 25.74 mM) had the best morphological and physiological indicators. The optimal doses of calcium ammonium nitrate and ammonium sulfate were found in treatments 3 and 4, as well as in the control, with no significant difference among them. However, treatment 3, due to its lower dose, was more cost effective. To improve cost efficiency in practical production, it is recommended to use the lower concentration ratio of treatment 3 for plant tissue culture plantlets.

Low N2O emissions induced by root-derived residues compared to aboveground residues of red clover or grass mixed into soil

The default The Intergovernmental Panel on Climate Change (IPCC) guidelines assume a constant N2O emission factor (EFN2O) for both belowground crop residues (BGR) and aboveground residues (AGR), and that ∼70 % of total N2O emissions following renewal of temporary grasslands come from BGR. However, empirical evidence is lacking, which motivated this study. BGR-free and BGR-rich clay loam collected in grass or red clover leys were incubated alone or mixed with AGR and different doses of nitrate over 107 days. The average EFN2O of BGR was around 18 % of that of AGR, and remained low even when soil nitrate concentration was very high, whereas EFN2O of AGR varied largely and rocketed even with a small increase in soil nitrate. The decomposition of the carbon present in crop residues was critical for N2O emissions. Lower EFN2O of BGR relative to AGR were related to slower C decomposition, which was not predicted by the biochemical characteristics. It is also likely that BGR were less conducive than AGR to develop into hotspots for N2O emission because of the roots’ finer distribution and closer contact with soil particles. Differences in EFN2O among AGR were mostly linked to the availability of N, either derived from residue mineralization or present in the soil. In conclusion, N2O accountings based on present IPCC default methodology likely overestimate the contribution by crops’ BGR.

Effects of a Single Dose of Dietary Nitrate via Beetroot Crystals on High-Intensity Intermittent Exercise Performance in Recreational Collegiate Athletes

Abstract: Endurance and high-intensity intermittent exercise are paramount in the pursuit of optimal athletic performance. Nitrate (NO₃⁻) supplementation has emerged as a promising avenue for enhancing these aspects. Prior studies underscore the beneficial role of nitrate supplementation in augmenting endurance and high-intensity intermittent exercise. The current study probes the immediate effects of nitrate supplementation, specifically beetroot crystals (BRC), on high-intensity intermittent running performance in recreational collegiate athletes. In a randomized, cross-over, placebo-controlled, double-blind investigation, fourteen male athletes consumed either an acute dose of BRC (25 g·day⁻¹, containing ~8.1 mmol of NO₃⁻) or a placebo (PLA; 25 g·day⁻¹ of maltodextrin) 1.5 hours prior to undergoing a high-intensity intermittent exercise test in a controlled laboratory setting. Results elucidated that BRC supplementation improved high-intensity intermittent exercise performance (BRC: 270.5 ± 138.5 s vs. PLA: 231.7 ± 141.5 s; p < 0.05) and elevated plasma NO₃⁻ and NO₂⁻ concentrations compared to the placebo group (p < 0.05). Nonetheless, blood pressure, muscle oxygenation, plasma lactate, and glucose levels did not reveal any significant differences (p > 0.05). Crucially, this study stands as the first to identify BRC as a significant enhancer of intermittent cycling performance in a controlled laboratory setting. These findings underscore the potential of acute BRC supplementation in boosting high-intensity intermittent exercise performance in recreational collegiate athletes, thereby prompting further investigation into its potential usage in sports and exercise scenarios. Keywords: endurance exercise, ergogenic aids, nitric oxide, recreational sports

Effects of Dietary Nitrate Supplementation on High-Intensity Cycling Sprint Performance in Recreationally Active Adults: A Systematic Review and Meta-Analysis.

This systematic review and meta-analysis investigated the influence of dietary nitrate supplementation on performance metrics during cycling sprint exercise according to the PRISMA guidelines. Searches were conducted on MEDLINE, PubMed, ScienceDirect, Scopus, and SPORTDiscus databases up to September 2023. Inclusion criteria were healthy recreationally active men and women who consumed nitrate-rich and nitrate-deficient beetroot juice to assess performance outcomes of mean power, peak power, time-to-peak power, and minimum power during 30-s cycling sprints. Risk of bias was assessed using the Cochrane Risk of Bias 2 and TESTEX tools and funnel plots. A random effects model was performed on six studies and showed that dietary nitrate had significant effects on time-to-peak power (SMD: -0.66, 95% CI: -1.127 to -0.192, p = 0.006) but not on mean power, peak power, or minimum power. Subgroup analysis revealed that an acute low nitrate dose improved time-to-peak power (SMD: -0.977, 95% CI: -1.524 to -0.430, p < 0.001) but not after a multiday moderate nitrate dose (SMD: -0.177, 95% CI: -0.619 to -0.264, p = 0.431). These data suggest that acute nitrate supplementation can benefit time-to-peak power during 30-s cycling sprints, but due to the limited availability of data and heterogeneity in methodology, these results should be interpreted with caution. There was insufficient data on women to analyze sex-based differences. Future studies are required to provide insight on how supplementation regimen and population impact the effects of dietary nitrate for enhancing cycling sprint performance.

Association of early doses of diuretics and nitrates in acute heart failure with 30 days outcomes: ancillary analysis of ELISABETH study.

The optimal dose of diuretics and nitrates for acute heart failure treatment remains uncertain. This study aimed to assess the association between intravenous nitrates and loop diuretics doses within the initial 4 h of emergency department presentation and the number of days alive and out of hospital (NDAOH) through 30 days. This was an ancillary study of the ELISABETH stepped-wedge cluster randomized trial that included 502 acute heart failure patients 75 years or older in 15 French emergency departments. The primary endpoint was the NDAOH at 30 days. The total dose of intravenous nitrates and loop diuretics administered in the initial 4 h were each categorized into three classes: 'no nitrate', '> 0-16', and '> 16 mg' for nitrates and '< 60', '60', and '> 60 mg' for diuretics. Secondary endpoints included 30-day mortality, 30-day hospital readmission, and hospital length of stay in patients alive at 30 days. Generalized linear mixed models were used to examine associations with the endpoints. Of 502 patients, the median age was 87 years, with 59% women. The median administered dose within the initial 4 h was 16 mg (5.0; 40.0) for nitrates and 40 mg (40.0; 80.0) for diuretics. The median NDAOH at 30 days was 19 (0.0-24.0). The adjusted ratios of the NDAOH were 0.88 [95% confidence interval (CI): 0.63-1.23] and 0.76 (95% CI: 0.58-1.00) for patients that received 60 and > 60 mg, respectively, compared with patients that received 40 mg or less of diuretics. Compared with patients who did not receive nitrates, the adjusted ratios of the NDAOH were 1.17 (95% CI: 0.82-1.67) and 1.45 (95% CI: 0.90-2.33) for patients who received 1-16 and > 16 mg, respectively. There was no significant association with any of the secondary endpoints. In this ancillary analysis, there was no significant association between different doses of diuretics and nitrates with the NDAOH at 30 days. Point estimates and CIs may suggest that the optimal doses are less than 60 mg of diuretics, and more than 16 mg of nitrates in the first 4 h.

Lanthanum nitrate demonstrated no genotoxicity in the conducted tests

Given the widespread applications in industrial and agricultural production, the health effects of rare earth elements (REEs) have garnered public attention, and the genotoxicity of REEs remains unclear. In this study, we evaluated the genetic effects of lanthanum nitrate, a typical representative of REEs, with guideline-compliant in vivo and in vitro methods. Genotoxicity assays, including the Ames test, comet assay, mice bone marrow erythrocyte micronucleus test, spermatogonial chromosomal aberration test, and sperm malformation assay were conducted to assess mutagenicity, chromosomal damage, DNA damage, and sperm malformation. In the Ames test, no statistically significant increase in bacterial reverse mutation frequencies was found as compared with the negative control. Mice exposed to lanthanum nitrate did not exhibit a statistically significant increase in bone marrow erythrocyte micronucleus frequencies, spermatogonial chromosomal aberration frequencies, or sperm malformation frequencies compared to the negative control (P > 0.05). Additionally, after a 24-h treatment with lanthanum nitrate at concentrations of 1.25, 5, and 20 μg/ml, no cytotoxicity was observed in CHL cells. Furthermore, the comet assay results indicate no significant DNA damage was observed even after exposure to high doses of lanthanum nitrate (20 μg/ml). In conclusion, our findings suggest that lanthanum nitrate does not exhibit genotoxicity.

The effect of different doses of ammonium nitrate on the yield and protein content in spring triticale grain

The article presents the results of studying the effect of various doses of ammonium nitrate on the yield and protein content in spring triticale grain. Numerous studies around the world have established that nitrogen is a key factor influencing the productivity of grain crops. The paper presents the results of a 5-year study (2018-2022) of cultivating spring triticale using fallow and stubble predecessors. Nitrogen fertilizer was applied when sowing in rows at a dose of 20 to 80 kg/ha in the active substance. The experiments were carried out in the Akmola region (LLP "SPCGF named after A. Barayev") on southern carbonate chernozem. Over the five years of research, only 2018 was characterized by optimal hydrothermal conditions during the triticale growing season, the remaining four years (2019-2022) were dry. The reserves of productive moisture in the meter layer of soil before sowing triticale in fallow were 119-138 mm, in stubble - 119-125 mm. The content of N-NO3 in the soil layer 0-40 cm before sowing triticale varied according to the years of research, so for fallow it varied from 11 to 28 mg/kg, and for stubble from 10 to 17 mg/kg of soil. The amount of P2O5 before sowing (in the soil layer of 0-20 cm), regardless of the predecessor, varied within 24-37 mg/kg of soil. It was not possible to establish a reliable effect of different doses of ammonium nitrate on grain yield and protein content in triticale grain using the two studied precursors. A strong correlation between the dose of nitrogen fertilizer and the yield of triticale based on the steam predecessor was established only in 2020 (r = 0.85) and in 2021 (r = 0.83). For stubble, a strong positive correlation between nitrogen doses and yield was noted in 2019 (r = 0.78), 2021 (r = 0.79) and 2022 (r = 0.87). A correlation between the protein content in triticale grain and nitrogen doses was established based on the fallow in 2 of 4 years (r = 0.86...0.96). For the stubble, a strong positive relationship was noted in all years of research (r = 0.83...0.99).

Determining the Potential of Lavender as Cut Flower: Enhancing Vase Life with Different Vase Solutions

Lavender, renowned for its pleasant aroma and beautiful spike structure, is a popular decorative plant often utilized in dried form for vase arrangements. However, its potential as a fresh cut flower has been relatively underexplored. This study aimed to assess the potential of lavender as a cut flower and investigate the impact of various vase solutions on its vase life. Two different lavender species türü (Lavandula angustifolia, Lavandula hybrida) were subjected to seven different vase solutions: control (water), two different doses of silver nitrate (AgNO3), salicylic acid, sodium hypochlorite, lavender essential oil, and vinegar. The effects of these solutions on vase life and overall quality were evaluated. Results indicate that lavender holds significant potential as a cut flower when placed in appropriate vase solutions. Among the solutions tested, silver nitrate treatments exhibited the longest vase life in both species, extending vase life up to threefold compared to the control, while also limiting microbial activity within the vase and preserving flower color. This study underscores the importance of selecting suitable vase solutions to maximize the vase life and aesthetic appeal of lavender as a cut flower.

Applying the fermentability coefficient concept in tropical grass silages

Two experiments were carried out to evaluate whether the fermentability coefficient (FC) concept is applicable to Megathyrsus and Urochloa genera and whether the forage nitrate content alters the fermentation pattern of the respective silages. Guinea grass [Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs (Syn. Panicum maximum Jacq.) cv. MG18 Aries II] and palisade grass [Urochloa brizantha (Hochst. ex A. Rich) R.D. Webster (syn. Brachiaria brizantha (A. Rich) Stapf) cv. Marandu] were used in both experiments. In experiment 1, a broad range of FC was induced by different dry matter (DM) content and soluble carbohydrates (SC):buffering capacity (BC) ratio. The DM content was modified by wilting (i.e., guinea grass: direct cut at ∼200 g/kg, wilted to ∼300 and ∼400 g/kg; palisade grass: direct cut at ∼250 g/kg and wilted to ∼400 g/kg) while the SC:BC ratio was modified by addition of glucose [0, 5 and 10 g/kg of fresh matter (FM)] resulting in a factorial arrangement of 3 × 3 for guinea grass and 2 × 3 for palisade grass, with three replications per treatment. In experiment 2, five doses of sodium nitrate (0, 0.15, 0.30, 1.5 and 3.0 g/kg FM) were added factorially to DM and glucose levels used in experiment 1, leading to a factorial arrangement of 3 × 3 × 5 for guinea grass and 2 × 3 × 5 for palisade grass, with three replications per treatment. Regression analyses were performed using the REG procedure of SAS. An independent dataset of tropical grasses and their silages (n = 226) was used to validate the FC model. The FC equation obtained for tropical grasses in the current study did not diverge from the model derived from temperate forages (i.e., FC = DM + 80 × SC:BC), as the regression slopes were similar (79 vs. 80; P = 0.92). There was a linear negative correlation between FC and minimum content of nitrate required to inhibit butyric fermentation, confirming the clostridia-inhibiting role of nitrate in tropical grass silages too. However, the effect size differed between grass genera. In conclusion, as proposed for temperate forages, FC values ≥350 markedly decreases the risk of butyric fermentation, whereas FC values ≥400 completely suppress butyric fermentation in tropical grasses with moderate levels of nitrate and epiphytic lactic acid bacteria (LAB). The FC required to curtail butyric fermentation decreased linearly with nitrate concentration. Nevertheless, the minimum nitrate content to inhibit Clostridium development during silage fermentation depended on the forage species.

The Role of Nitrate Supply in Bioactive Compound Synthesis and Antioxidant Activity in the Cultivation of Porphyra linearis (Rhodophyta, Bangiales) for Future Cosmeceutical and Bioremediation Applications.

Porphyra sensu lato has economic importance for food and pharmaceutical industries due to its significant physiological activities resulting from its bioactive compounds (BACs). This study aimed to determine the optimal nitrate dosage required in short-term cultivation to achieve substantial BAC production. A nitrate experiment using varied concentrations (0 to 6.5 mM) revealed optimal nitrate uptake at 0.5 mM in the first two days and at 3 and 5 mM in the last five days. Polyphenols and carbohydrates showed no differences between treatments, while soluble proteins peaked at 1.5 and 3 mM. Total mycosporine-like amino acids (MAAs) were highest in algae incubated at 5 and 6.5 mM, and the highest antioxidant activity was observed in the 5 mM, potentially related to the MAAs amount. Total carbon and sulfur did not differ between treatments, while nitrogen decreased at higher nitrate. This discovery highlights the nuanced role of nitrate in algal physiology, suggesting that biological and chemical responses to nitrate supplementation can optimize an organism's health and its commercially significant bioactive potential. Furthermore, given its ability to absorb high doses of nitrate, this alga can be cultivated in eutrophic zones or even in out-/indoor tanks, becoming an excellent option for integrated multi-trophic aquaculture (IMTA) and bioremediation.

Can the dietary inorganic nitrate supplementation mitigate the vascular dysfunction in elderly with Alzheimer’s disease?

Aging and Alzheimer disease (AD) are both characterized by progressive reduction in nitric oxide bioavailability and endothelial function impairment. Promising studies on young healthy individuals underly the positive effect of dietary nitrate supplementation on endothelial function. However, the pharmacokinetics of the plasma nitrate and nitrite (PN) and the accompanying endothelial responsiveness following the oral nitrate ingestion in healthy elderly (HE) and patients with AD is not clear. Our hypothesis was that due to the reduction of nitric oxide bioavailability during aging and AD, an equal dose of oral nitrate (ON) would ameliorate the endothelial responsiveness more in the HE and even more in patients with AD in comparison to healthy young subjects (HY). Therefore, with the aim of investigating the pharmacokinetics of PN and the time-course endothelial responsiveness in response to a single dose ON, 10 HY (25±4 YRS), 10 HE (72±8 YRS) and 13 AD (73±7 YRS) were recruited. PN levels and endothelial responsiveness (single-passive leg movement (ΔPLM)) were measured in the recruited individuals prior to (T0) and hourly for 4 hours (T1, T2, T3, and T4) after: a) a single dose of ON; and b) a single dose of placebo. As expected at T0 both PN and ΔPLM were significantly reduced in the HE and even more reduced in the AD in comparison to the HY (all p&lt;0.001). No changes in PN nor ΔPLM were detected in any group following placebo intake. PN increased significantly in all three groups at T1 (p&lt;0.001) and constantly increased up to T4, but no differences were detected between time points T1 to T4 in any group. ΔPLM increased significantly in all three groups at T2, reaching highest values at T4 (p&lt;0.001). However, AD exhibited significantly lower ΔPLM values at any time point compared to HY (p&lt;0.0001) and HE (p&lt;0.001). Significant correlation between PN and ΔPLM was found (p&lt;0.001, R2=0.1654). Contrary to our hypothesis, the results of this study suggest that the PN pharmacokinetics following a single dose of ON is similar in HY, HE and AD. Moreover, the expected time-course amelioration of the endothelial responsiveness was reduced in the HE and even more reduced in the AD, suggesting that other factors, rather than the nitric oxide bioavailability, are playing a role in the age- and AD-related vascular dysfunction. Ricerca di Base 2017 - RBVR17XRSA - Effectiveness of exercise and nitrate supplementation on progression of dementia in patients with Alzheimer’s disease. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Dietary nitrate flows and accumulation in pig organs:15N-tracer study

Nitric oxide (NO) is a free radical with multiple functions in virtually all cells. In mammals, NO is generated by nitric oxide synthase from arginine and by reduction of nitrate to nitrite by tissue xanthine oxidoreductase (XOR) and microbiome. Nitrite is then available for reduction to NO by XOR or several heme proteins. Previously we reported that 1) skeletal muscle acts as a body nitrate reservoir, and 2) stored nitrate is systemically, as well as locally used to generate nitrite and NO. Recently, we identified two additional nitrate storage organs - skeleton and skin. At baseline conditions, nitrate concentration in skeleton was 96±63 nmol/g, skeletal muscle 57±39 nmol/g and skin 56±22 nmol/g. For comparison, plasma and liver contained 34±19 nmol/g and 15±5 nmol/g of nitrate, respectively. We used 15N-labeled dose of dietary nitrate to trace its distribution among organs in time. Three hours after nitrate bolus ingestion, total nitrate levels significantly increased in all organs, reaching 221±91 nmol/g in plasma, 126±55 nmol/g in skin, 119±38 nmol/g in skeleton, 100±79 mmol/g in skeletal muscle, and 21±5 nmol/g in liver. As shown by MS, 15N-labeled nitrate distributes in non-uniform way, accumulating largely in skin. As expected, nitrate reductase activity is highest in liver, but also substantial in skin and skeletal muscle, as seen by presence of 15N-labeled nitrite. With consideration of skeletal muscle, skin and skeleton as three largest organs in mammals, these results underline their major role in maintaining homeostasis of the nitrate-nitrite-nitric oxide pathway. Also, important from therapeutic point of view, all three organs are well responding to dietary nitrate interventions by increasing their respective nitrate levels, which leads to general increase of systemic and local NO and perhaps could be used as one of the ways to increase NO availability. Work supported by NIH internal grant to ANS. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Methane mitigation via the nitrite-DAMO process induced by nitrate dosing in sewers

Nitrate or nitrite-dependent anaerobic methane oxidation (n-DAMO) is a microbial process that links carbon and nitrogen cycles as a methane sink in many natural environments. This study demonstrates, for the first time, that the nitrite-dependent anaerobic methane oxidation (nitrite-DAMO) process can be stimulated in sewer systems under continuous nitrate dosing for sulfide control. In a laboratory sewer system, continuous nitrate dosing not only achieved complete sulfide removal, but also significantly decreased dissolved methane concentration by ∼50 %. Independent batch tests confirmed the coupling of methane oxidation with nitrate and nitrite reduction, revealing similar methane oxidation rates of 3.68 ± 0.5 mg CH4 L−1 h−1 (with nitrate as electron acceptor) and 3.57 ± 0.4 mg CH4 L−1 h−1 (with nitrite as electron acceptor). Comprehensive microbial analysis unveiled the presence of a subgroup of the NC10 phylum, namely Candidatus Methylomirabilis (n-DAMO bacteria that couples nitrite reduction with methane oxidation), growing in sewer biofilms and surface sediments with relative abundances of 1.9 % and 1.6 %, respectively. In contrast, n-DAMO archaea that couple methane oxidation solely to nitrate reduction were not detected. Together these results indicated the successful enrichment of n-DAMO bacteria in sewerage systems, contributing to approx. 64 % of nitrite reduction and around 50 % of dissolved methane removal through the nitrite-DAMO process, as estimated by mass balance analysis. The occurrence of the nitrite-DAMO process in sewer systems opens a new path to sewer methane emissions.

Piped-slow-release calcium nitrate dosing: A new approach to in-situ sediment odor control in rural areas

Calcium nitrate addition is economically viable and highly efficient for the in-situ treatment of contaminated sediment and enhancement of surface water quality, particularly in rural areas. However, conventional nitrate addition technologies have disadvantages such as excessive nitrate release, sharp ammonium increase, and weakened sulfide oxidation efficiency owing to rapid nitrate injection into the sediment. To resolve these defects, we propose a piped-slow-release (PSR) calcium nitrate dosing method and investigate its treatment efficiency and underlying mechanisms. The results illustrated that PSR dosing had a longer half-life (t1/2 = 5.08 days) and a lower maximum apparent nitrate escape rate of 1.28 % than conventional nitrate injection and other dosing methods. In addition, the PSR managed the inorganic nitrogen release into the overlying water, and after the treatment, the nitrate, ammonium, and nitrite concentrations of 0 mg/L, 8.60 mg/L, and 0 mg/L on day 28 were close to those of the control group (0 mg/L, 8.76 mg/L, and 0 mg/L, respectively). Moreover, the PSR method maintained a moderate nitrate concentration of approximately 3000 mg/L in sediment interstitial water by its controlled-release design, thus greatly enhancing the sulfide oxidation efficiency by relieving the inhibitory effects of high nitrate concentrations, with 83.0 % sulfide being eradicated within 5 days. Sulfide-ferrous nitrate reduction (denitrification and dissimilatory nitrate reduction to ammonium) genera (e.g., Sulfurimonas, Thiobacillus, and Thioalkalispira) were successively enhanced and dominated the microbial community, and the related functional genes displayed high relative abundances. These results imply that the PSR dosing method for calcium nitrate, characterized by flexible operation, high efficiency, low cost, and controllable processes, is appropriate for remediating black-odorous sediment in rural areas.

THE ADVANTAGES OF SYDNONIMINES COMPARED TO NITRATES IN THE TREATMENT OF PATIENTS WITH ISCHEMIC HEART DISEASE AND CORONARY INSUFFICIENCY

One of the primary challenges in treating patients with coronary artery disease and coronary insufficiency using nitrates is the development of tolerance. Nitrate tolerance is a condition in which the duration and intensity of anti-anginal and anti-ischemic effects decrease, despite maintaining a high concentration of the drug in the blood. In cases of developing tolerance, a continual increase in the nitrate dose is necessary to achieve the previous effect. To eliminate developed nitrate tolerance, discontinuing nitrates for 3-5 days is typically sufficient. Currently, molsidomine is employed as an alternative to nitrates, with sydnonimines emerging as a noteworthy substitute. Among sydnonimines, molsidomine (marketed as Sydnopharm, Dilasidom, Corvaton) stands out as the most effective. Despite its chemical distinction from nitrates, molsidomine operates through a similar mechanism. Functioning as a nitric oxide donor, this antianginal drug avoids the development of tolerance even with prolonged use. Molsidomine, akin to nitrates, acts as a vasodilator, exhibiting efficacy as an anti-ischemic and anti-anginal medication when administered in appropriate doses. Upon entering the human body, molsidomine undergoes hepatic metabolism, transforming into an active derivative compound known as SIN-1. This metabolite, upon entering the bloodstream, further converts into an active form (SIN-1A). From this active metabolite, the nitric oxide (NO) group is released, influencing the activation of guanylate cyclase. This activation prompts guanosine triphosphate to convert into cyclic guanosine triphosphate, ultimately contributing to the synthesis of proteins that bind calcium. This cascade of events results in the vasodilatory effect of molsidomine. Indications for molsidomine include stable angina pectoris, acute coronary syndrome, early post-infarction angina, congestive heart failure, portal hypertension, pulmonary hypertension, and Aerz's disease. Possible side effects following the therapy with molsidomine (dizziness, headache, and diplopia) occur much less frequently compared to nitrates. After using nitrates, such a side effect as methemoglobinемia may occur. Therapy with molsidomine does not lead to the development of this side effect.

Investigating the association between nitrate dosing and nitrite generation by the human oral microbiota in continuous culture.

The generation of nitrite by the oral microbiota is believed to contribute to healthy cardiovascular function, with oral nitrate reduction to nitrite associated with systemic blood pressure regulation. There is the potential to manipulate the composition or activities of the oral microbiota to a higher nitrate-reducing state through nitrate supplementation. The current study examined microbial community composition and enzymatic responses to nitrate supplementation in sessile oral microbiota grown in continuous culture. Nitrate reductase (NaR) activity and nitrite concentrations were not significantly different to tongue-derived inocula in model biofilms. These were generally dominated by Streptococcus spp., initially, and a single nitrate supplementation resulted in the increased relative abundance of the nitrate-reducing genera Veillonella, Neisseria, and Proteus spp. Nitrite concentrations increased concomitantly and continued to increase throughout oral microbiota development. Continuous nitrate supplementation, over a 7-day period, was similarly associated with an elevated abundance of nitrate-reducing taxa and increased nitrite concentration in the perfusate. In experiments in which the models were established in continuous low or high nitrate environments, there was an initial elevation in nitrate reductase, and nitrite concentrations reached a relatively constant concentration over time similar to the acute nitrate challenge with a similar expansion of Veillonella and Neisseria. In summary, we have investigated nitrate metabolism in continuous culture oral biofilms, showing that nitrate addition increases nitrate reductase activity and nitrite concentrations in oral microbiota with the expansion of putatively NaR-producing taxa.IMPORTANCEClinical evidence suggests that blood pressure regulation can be promoted by nitrite generated through the reduction of supplemental dietary nitrate by the oral microbiota. We have utilized oral microbiota models to investigate the mechanisms responsible, demonstrating that nitrate addition increases nitrate reductase activity and nitrite concentrations in oral microbiota with the expansion of nitrate-reducing taxa.

Physicochemical properties and sensory features of ripened, industrially prepared sausages, enriched with olive leaf extract to replace nitrite and nitrate

The use of nitrite and nitrate in meat products has been questioned due to the generation of N-nitroso compounds with carcinogenic effects. Thus, research has been focused on their replacement with several alternatives. This study is focused on evaluating the effects of a commercial olive leaf extract (OLE), marketed as dietary supplement, on protein and lipid oxidation, N-nitrosamine content and sensory properties of industrial sausages at the end of the ripening period. Five different formulations were prepared: F1 (OLE: 1000 mg/kg; NO2–NO3: 0 mg/kg), F2 (OLE: 1000 mg/kg; NO2–NO3: 75-75 mg/kg), F3 (OLE: 0 mg/kg; NO2–NO3: 0 mg/kg), F4 (OLE: 0 mg/kg; NO2–NO3: 75-75 mg/kg), F5 (OLE: 500 mg/kg; NO2–NO3: 35-35 mg/kg). The use of OLE in combination with a reduced dose of nitrite and nitrate (F5) significantly reduced the lipid and protein oxidation (p < 0.05) compared to the formulation with synthetic additives alone (F4). No differences were observed in terms of textural properties with the samples without the extract. The OLE did not affect the microbiological quality and enabled a significant reduction in the N-nitrosamines content. However, the addition of OLE decreased the intensity of red colour and determined the insurgence of a slight bitter taste in the sausages.