Nitrite Concentrations Research Articles

Impact of an active lifestyle on cardiovascular autonomic modulation and oxidative stress in males with overweight and parental history of hypertension.

Family history of hypertension is associated with early autonomic dysfunction and increased oxidative stress. These alterations have been found to be reinforced by the overweight factor. Conversely, an active lifestyle is effective in improving the mechanisms regulating blood pressure control. Hence, we ought to investigate the effects of an active lifestyle on the hemodynamic, autonomic and oxidative stress parameters in individuals carrying both family history of hypertension and overweight risk factors. Fifty-six normotensive males were divided into four groups: eutrophic offspring of normotensive parents (EN, n = 12), eutrophic and inactive with hypertensive parents (EH, n = 14), overweight and inactive with hypertensive parents (OH, n = 13), and overweight and physically active with hypertensive parents (OAH, n = 17). Cardiovascular autonomic modulation was assessed by heart rate (HRV) and blood pressure (BPV) variability indexes. Oxidative stress included pro/antioxidant markers and nitrite concentration. Inactive offspring of hypertensive parents (EH and OH) showed higher LFSBP (vs EN), an indicator of sympathetic outflow to the vasculature and reduced anti-oxidant activity (vs EN), while higher pro-oxidant markers were found exclusively in OH (vs EN and EH). Conversely, the OAH group showed bradycardia, higher vagally-mediated HFabs index (vs OH and EN), lower sympathovagal balance (vs OH) and preserved LFSBP. Yet, the OAH showed preserved pro/antioxidant markers and nitrite levels. Our findings indicates that overweight offspring of hypertensive parents with an active lifestyle have improved hemodynamic, cardiac autonomic modulation and oxidative stress parameters compared to their inactive peers.

Effects of carbon to nitrogen ratio on nitrogen removal in a single-stage microaerobic system: A model-based evaluation

Single-stage microaerobic systems have been proven to be effective for concurrent removal of ammonium and organic carbon from sewage. While mechanistic models derived from activated sludge models (ASMs) have simulated nutrients removal under microaerobic conditions, classic ASMs exhibit limitations in capturing the intricate effects of carbon to nitrogen (C/N) ratio on nitrogen removal performance. To address this issue, a mechanistic model modified from the classic ASMs was proposed to capture the combined inhibitory effects of carbon and ammonium on microaerobic systems. This modified model was established based on experimental data from a single-stage microaerobic reactor encompassing simultaneous nitrification-denitrification and anammox processes. The inhibition coefficient of C/N ratio was integrated into the process rate equations, and its effectiveness was validated through model performance evaluation. Compared to the classic models, the modified one achieved superior predictions for nitrite and nitrate nitrogen concentrations. Simulations revealed that under optimized conditions with a C/N of 4.57 and a dissolved oxygen (DO) of 0.41 mg/L, the system could achieve up to 95.5% of total nitrogen (TN) removal efficiency. Based on the simulation of substrate uptake/production rate, increasing the nitrogen loading rate (NLR) rather than organic loading rate (OLR) was crucial for efficient nitrogen removal. The proposed modified model served as a valuable tool for designing and optimizing similar biological wastewater treatment systems.

Pilot-scale plasma activated water treatment for decontaminating romaine lettuce and steamed rice cakes

The study investigated the effects of pilot-scale plasma activated water (PAW) on the inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and indigenous mesophilic aerobic bacteria on romaine lettuce and steamed rice cake (SRC). PAW treatment was conducted by stirring 25 g of romaine lettuce and 80 g of SRC for 20–40 min at 195 rpm in 1 L of PAW, prepared by treating sterile distilled water with surface dielectric barrier discharge for 40 or 60 min. The microbial inactivation rates of foodborne pathogens and indigenous mesophilic aerobic bacteria ranged from 1.3 to 2.5 log on romaine lettuce and SRC, along with PAW generation time (P < 0.05). Inactivation rates of PAW generation time or treatment time against romaine lettuce and SRC were significantly different to the inactivation of distilled water treatments, respectively (P < 0.05). The pH, electrical conductivity, and hydrogen ion concentration correlated with nitrite and nitrate concentrations of PAW prepared at various PAW generation time. In situ pilot-scale PAW treatment also extended the shelf life of the romaine lettuce. The study demonstrates the feasibility of the pilot-scale PAW treatment to improve microbiological safety and its suitability of applying PAW to manufacture romaine lettuce and SRC products.

Relationships between nitric oxide biomarkers and physiological outcomes following dietary nitrate supplementation

Dietary nitrate (NO3−) supplementation can increase nitric oxide (NO) bioavailability, reduce blood pressure (BP) and improve muscle contractile function in humans. Plasma nitrite concentration (plasma [NO2−]) is the most oft-used biomarker of NO bioavailability. However, it is unclear which of several NO biomarkers (NO3−, NO2−, S-nitrosothiols (RSNOs)) in plasma, whole blood (WB), red blood cells (RBC) and skeletal muscle correlate with the physiological effects of acute and chronic dietary NO3− supplementation. Using a randomized, double-blind, crossover design, 12 participants (9 males) consumed NO3−-rich beetroot juice (BR) (∼12.8 mmol NO3−) and NO3−-depleted placebo beetroot juice (PL) acutely and then chronically (for two weeks). Biological samples were collected, resting BP was assessed, and 10 maximal voluntary isometric contractions of the knee extensors were performed at 2.5–3.5 h following supplement ingestion on day 1 and day 14. Diastolic BP was significantly lower in BR (−2 ± 3 mmHg, P = 0.03) compared to PL following acute supplementation, while the absolute rate of torque development (RTD) was significantly greater in BR at 0–30 ms (39 ± 57 N m s−1, P = 0.03) and 0–50 ms (79 ± 99 N m s−1, P = 0.02) compared to PL following two weeks supplementation. Greater WB [RSNOs] rather than plasma [NO2−] was correlated with lower diastolic BP (r = −0.68, P = 0.02) in BR compared to PL following acute supplementation, while greater skeletal muscle [NO3−] was correlated with greater RTD at 0–30 ms (r = 0.64, P=0.03) in BR compared to PL following chronic supplementation. We conclude that [RSNOs] in blood, and [NO3−] in skeletal muscle, are relevant biomarkers of NO bioavailability which are related to the reduction of BP and the enhanced muscle contractile function following dietary NO3− ingestion in humans.

Aquaponics Vs. Recirculating Aquaculture System: Assessing Productivity and Water Use Efficiency of Native Fish Species Empurau (Tor tambroides) and Jelawat (Leptobarbus hoevenii) Compared to Red Hybrid Tilapia

A 3 × 2 (fish species × culture system) factorial design experiment was conducted to compare productivity of empurau (Tor tambroides), jelawat (Leptobarbus hoevenii) and red hybrid tilapia (Oreochromis sp., control) cultured in recirculating aquaculture system (RAS) and aquaponics system. Growth performance, feed conversion ratio (FCR) and survival rate of fish were evaluated, and water quality of all tanks throughout the 70-days experiment was determined. In the present study, FCR of tilapia, empurau and jelawat tended to be lower in aquaponics than RAS, while no significant differences (P&gt;0.05) on weight gain (WG) and specific growth rate (SGR) between RAS and aquaponics for each fish species were observed. Although tilapia had significantly higher WG and SGR, and lower FCR compare to empurau and jelawat, the survival rate of empurau and jelawat were higher than tilapia, regardless of the culture system. Between empurau and jelawat, better growth performance was observed in aquaponics than in RAS. Significantly higher (p&lt;0.05) ammonia and nitrite concentrations were shown in RAS tanks as compared to aquaponics tanks, regardless of the fish species. Jelawat might have wide range tolerance to ammonia as no mortality in both RAS and aquaponics, while tilapia and empurau had higher survival rate in aquaponics than RAS. In summary, aquaponics appears to be a viable approach to enrich variety and improve fish production in an environmentally responsible manner. Therefore, it is plausible to advocate for the use of aquaponics as a sustainable methods of farming native fish species in Malaysia.

Ecology of aerobic anoxygenic phototrophs on a fine-scale taxonomic resolution in Adriatic Sea unravelled by unsupervised neural network

BackgroundAerobic anoxygenic phototrophs are metabolically highly active, diverse and widespread polyphyletic members of bacterioplankton whose photoheterotrophic capabilities shifted the paradigm about simplicity of the microbial food chain. Despite their considerable contribution to the transformation of organic matter in marine environments, relatively little is still known about their community structure and ecology at fine-scale taxonomic resolution. Up to date, there is no comprehensive (i.e. qualitative and quantitative) analysis of their community composition in the Adriatic Sea.ResultsAnalysis was based on pufM gene metabarcoding and quantitative FISH-IR approach with the use of artificial neural network. Significant seasonality was observed with regards to absolute abundances (maximum average abundances in spring 2.136 ± 0.081 × 104 cells mL−1, minimum in summer 0.86 × 104 cells mL−1), FISH-IR groups (Roseobacter clade prevalent in autumn, other Alpha- and Gammaproteobacteria in summer) and pufM sequencing data agglomerated at genus-level. FISH-IR results revealed heterogeneity with the highest average relative contribution of AAPs assigned to Roseobacter clade (37.66%), followed by Gammaproteobacteria (35.25%) and general Alphaproteobacteria (31.15%). Community composition obtained via pufM sequencing was dominated by Gammaproteobacteria clade NOR5/OM60, specifically genus Luminiphilus, with numerous rare genera present in relative abundances below 1%. The use of artificial neural network connected this community to biotic (heterotrophic bacteria, HNA and LNA bacteria, Synechococcus, Prochlorococcus, picoeukaryotes, heterotrophic nanoflagellates, bacterial production) and abiotic environmental factors (temperature, salinity, chlorophyll a and nitrate, nitrite, ammonia, total nitrogen, silicate, and orthophosphate concentration). A type of neural network, neural gas analysis at order-, genus- and ASV-level, resulted in five distinct best matching units (representing particular environments) and revealed that high diversity was generally independent of temperature, salinity, and trophic status of the environment, indicating a potentially dissimilar behaviour of aerobic anoxygenic phototrophs compared to the general bacterioplankton.ConclusionThis research represents the first comprehensive analysis of aerobic anoxygenic phototrophs in the Adriatic Sea on a trophic gradient during a year-round period. This study is also one of the first reports of their genus-level ecology linked to biotic and abiotic environmental factors revealed by unsupervised neural network algorithm, paving the way for further research of substantial contribution of this important bacterial functional group to marine ecosystems.

РАСПРЕДЕЛЕНИЕ БИОГЕННЫХ ЭЛЕМЕНТОВ НА ГРАНИЦЕ ВОДА–ДНО В ПОРОВЫХ И НАДДОННЫХ ВОДАХ КАРСКОГО МОРЯ И МОРЯ ЛАПТЕВЫХ

The paper presents data from the 63rd cruise of the R/V “Akademik Mstislav Keldysh” in August–October 2015. The main areas of work included the western part of the Kara Sea, the bays of Novaya Zemlya (Sedova, Oga and Tsivolki), a transect through the Voronin Trench, a transect from the Lena River delta to the continental slope of the Laptev Sea. During the cruise, a chemical analysis of pore and bottom waters was carried out for the content of nitrite, nitrate nitrogen, silicon, phosphates, total alkalinity and pH. The patterns of distribution of silicon and phosphorus concentrations at the water-bottom interface are considered. In the Kara Sea analysis of the data showed that the maximum concentrations of nutrients are located in the upper 10 cm sediment layer, below that concentrations gradually decrease. In all studied bays of Novaya Zemlya, the concentrations of nutrients in the silt waters were lower than on the adjacent shelf. In the Laptev Sea, the content of nitrates in silt waters is higher, and phosphates are lower than in the Kara Sea. Differences in the content of nutrients in the bottom and silt water are associated both with external factors (river runoff) and physical and geological features of the upper sediment layer of the studied areas.

Characteristics and key driving factors of nitrous oxide emissions from a full-scale landfill leachate treatment system

The characteristics of N2O emission from a full-scale landfill leachate treatment system were investigated by in-situ monitoring over 1.4 years and driving factors responsible for these emissions were identified by statistical analysis of multidimensional environmental variables. The results showed that the maximum N2O emission flux of 2.21 × 107 mg N·h−1 occurred in the nitrification tanks, where 98.5 % of the total N2O was released, with only 1.5 % of the total N2O emitted from the denitrification tanks. Limited oxygen in nitrification tank was responsible for N2O hotspot. The N2O emissions from the parallel lines A and B (both comprising the primary biochemical system) accounted for 52.6 % and 46.6 %, respectively, while the secondary biochemical system contributed only 0.8 % to the total emissions. Higher nitrite concentration in line A and lower nitrogen loading in the secondary biochemical system caused these discrepancies. We found that during the steady state of leachate treatment, intensive N2O emissions of 253.4–1270.5 kg N·d−1 were measured. The corresponding N2O emission factor (EF) ranged from 8.86 to 49.6 %, much higher than those of municipal wastewater treatment. But N2O EF was inconceivably as low as 0.42 % averagely after system maintenance. Influent with low salinity was the key reason, followed by the high MLSS and varying microbial community after maintenance. The dominant genus shifted from Lentimicrobium and Thauera to Norank-F-Anaerolineaceae and Unclassified-F-Rhodocyclaceae. This study underscores the significance of landfill leachate treatment in urban nitrogen management and provides valuable insights into the characteristics and driving factors of N2O emissions from such systems. The findings offer important references for greenhouse gas emission inventories and strategies for N2O control in full-scale wastewater treatment plants.

Effect of per os administration of fucoxanthin alcoholic and oil extracts to Balb/c mice on biochemical parameters and serum cytokine level

Microalgae are a source of various biologically active substances, including carotenoids. One of the carotenoids of diatom microalgae is fucoxanthin, which has antioxidant, antimicrobial, antitumour and anti-inflammatory properties that can be used in the treatment of a wide range of human and animal pathologies. The aim of the study was to investigate the effect of alcohol and oil extract of fucoxanthin on biochemical parameters and levels of serum cytokines in mice during intragastric administration. Material and methods. Fucoxanthin extracts from the microalga Nanofrustulum shiloi were used. Mice of Balb/c strain were intragastrically administrated with 0.5 ml of oil (500 μg/ml) or alcoholic extract of fucoxanthin (187.5 μg/ml), mice in the comparison group were given 0.5 ml of olive oil or 45% ethyl alcohol once a day within 5 days. On the 8th day, blood serum was obtained and the level of albumin, triglycerides, cholesterol, low (LDL) and high density lipoproteins (HDL), urea, uric acid, creatinine, aspartate (AST) and alanine aminotransferases (ALT), lactate, stable nitric oxide (NO) metabolites (nitrites), cytokines (IL-1β, IL-6, IL-10, TNF-α, IFN-γ) was determined using ELISA with photometric detection. Results and discussion. In the comparison group, ethyl alcohol promoted an increase in serum triglyceride, cholesterol, LDL, HDL, ALT, AST, nitrite, IL-10, IFN-γ and TNF-α content compared to intact animals. Fucoxanthin alcoholic extract administration increased the level of LDL, HDL, uric acid, TNF-α and decreased albumin, cholesterol, uric acid, creatinine, ALT, AST, IL-6 content compared to control. The olive oil group showed a decrease in serum triglycerides, cholesterol, urea, uric acid, ALT and AST content but an increase in LDL, HDL, nitrite level compared to the control. Administration of fucoxanthin oil extract to animals decreased albumin, triglycerides, cholesterol, HDL, uric acid, ALT, AST, lactate, IL-6, IL-10 compared to control. Conclusions. Thus, it was discovered that fucoxanthin in Balb/c mice contributes to a decrease in hepatic synthetic function, as evidenced by the change in the concentration of albumin, triglycerides, uric acid), influences energy metabolism (creatinine, lactate), cell membrane stability (cholesterol, LDL, HDL), serum transaminase activity, pro- and anti-inflammatory cytokines content.

Prenatal treatment with nitrite reduces pulmonary arteriolar remodeling in neonates with congenital diaphragmatic hernia

Therapeutic use of alternative nitric oxide (NO) sources, such as nitrite and nitrate may be a protective influence on pulmonary vasculature abnormalities. AimTo evaluate whether the maternal administration of nitrite prevents the morphological and molecular changes that affect the pulmonary arterioles of congenital diaphragmatic hernia (CDH) neonates. MethodsCEUA #88/2017. Sprague-Dawley neonate rats were divided into 6 groups: 1. control; 2. control + nitrite; 3. nitrofen exposed; 4. nitrofen exposed + nitrite; 5. CDH and 6. CDH + nitrite. The pregnant rats from nitrofen exposed and CDH groups were exposed to nitrofen on gestational day (GD) 9.5. The treatment with nitrite was made by gavage (15 mg/kg/day), on the last five gestational days. On GD 21.5 the fetuses were harvested. The following parameters were analyzed: lung and plasma nitrite concentration; media wall thickness (MWT) and endothelial NO synthase eNOS and inducible NO synthase iNOS immunohistochemistry of pulmonary arterioles. ResultsNitrite treatment increased the maternal plasma concentration of nitrite in control and nitrofen-exposed rats. All neonates exposed to nitrofen showed an increase of nitrofen in the lung and plasma. Nitrite treatment decreased the MWT of pulmonary arterioles of CDH neonates. Nitrite treatment increased eNOS marker and attenuated iNOS marker in neonates with CDH. ConclusionsNitrite maternal treatment rescued the morphometry and recovered eNOS expression of CDH pulmonary arterioles during CDH. Nitrite is a potential prenatally therapeutic approach to vascular alterations present in CDH neonates.

Integrative liquid chromatography-tandem mass spectrometry metabolomics and high-throughput sequencing technology reveal physicochemical characteristics and bacterial diversity of traditionally pickled mustard tuber from different regions of China

Abstract Objectives This work aimed to investigate and compare the physicochemical properties and bacterial diversity of traditionally pickled mustard tuber from different regions in China. Materials and Methods The pickles were obtained from Ningbo (NB), Nei Monggol (NMG), and Harbin (HEB). The pH was monitored by a pH meter. The titratable acidity and salinity were determined via titrimetric analysis. The nitrite content was measured using N-(1-naphthyl)-ethylenediamine dihydrochloride spectrophotometric method. The organic acids were detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The bacterial diversity was conducted through Illumina high-throughput sequencing platform. Results There were significant differences in the physicochemical properties of pickled mustard tuber from various locations, with the NB pickles having the highest pH, salinity, and nitrite content and the lowest titratable acidity. Importantly, pickles with higher titratable acidity levels had relatively lower nitrite and salinity contents. A total of 63 organic acids were detected, with lactic acid and succinic acid being the most prevalent. Moreover, the organic acid compositions of the NMG and HEB samples were more similar than those of the NB pickles. Additionally, bioinformatic analysis revealed that Firmicutes and Proteobacteria appeared as the predominant bacterial phyla in all samples. Among these, Lactobacillus was the major genera. The most abundant bacteria were found in the HEB pickles. Further correlation analysis showed that there was a strong correlation between bacterial community and 11 internal physicochemical parameters. Conclusions This study could contribute to a better understanding of the physicochemical characteristics and bacterial diversity of pickled mustard tuber from different locations.

Improving the bacterial community, flavor, and safety properties of northeastern sauerkraut by inoculating autochthonous Levilactobacillus brevis

The effect of Levilactobacillus brevis as a starter in northeastern sauerkraut fermentation is still unknown, and further evaluation is worthwhile. Hence, this study aimed to evaluate the effect of autochthonous L. brevis inoculation on the bacterial community succession and formation of flavor and harmful substances in sauerkrauts. Inoculation with L. brevis lowered the pH and increased the total acid content of sauerkrauts (P < 0.05). The nitrite content of the inoculated sauerkraut was significantly lower than that of control (P < 0.05). Moreover, the spoilage bacteria of the inoculated sauerkraut were decreased and nitrogen metabolism was improved. The contents of aldehydes, alcohols, esters, acids, and alkanes increased significantly (P < 0.05), and the sensory attributes such as aroma, sourness, and gloss were also improved. L. brevis was positively and negatively correlated with flavor metabolites and nitrite, respectively, which proved to be a potential starter culture to manufacture sauerkraut.

Potential valorization and transformation of plastic biomass waste into useful fertilizers in agricultural Mediterranean soils under extreme climate conditions

Plastics are widely used in agricultural practices, although recently they have been recognized as a new emerging risk in soils. Polyethylene (PE), is commonly used by farmers to cover agricultural practices; geotextile, is used mainly for ground and crop covering; and polyvinyl chloride (PVC) is considered the main material contained in irrigation hoses. The present study aimed to assess the effects of three plastics (polyethylene, geotextile, polyvinyl chloride) on the soils’ fertility. Several pot experiments were conducted in soil samples from the study area (Thessaly) contaminated with adequate amounts of each plastic type (PE, geotextile: 2% v/v and PVC: 5% v/v). Water was added in two quantities: one to maintain typical soil moisture levels according to the crops’ requirements and an elevated amount to form supersaturating soil conditions similar to those following a flood event. Furthermore, temperature effect was also investigated to assess its impact on plastics’ behavior and soil fertility. The levels of all nitrogen forms and the microbial activity were determined at 10, 30, and 60 days. Significant changes were observed in the concentrations of nitrate, nitrite, and ammonium ions under ambient soil moisture conditions especially when the microplastics were incubated for a longer period. PE addition resulted in greater changes, followed by geotextile, although PVC addition did not induce significant changes in the nitrification process during the experimental time. PE and geotextile microplastics appeared to enhance microbial colonization and total microbial activity. In addition, soil characteristics were notably altered when moisture stress conditions were reached (85%) and when soils were flooded for two months, leading to a severe decrease in the availability of all nitrogen forms. The results showed that alterations in soil nitrogen forms in the presence of plastics study are crucial for maintaining the health and improving the productivity of Mediterranean soils.

Proteomic profiling of antibiotic-resistant Escherichia coli GW-AmxH19 isolated from hospital wastewater treated with physical plasma.

Microorganisms which are resistant to antibiotics are a global threat to the health of humans and animals. Wastewater treatment plants are known hotspots for the dissemination of antibiotic resistances. Therefore, novel methods for the inactivation of pathogens, and in particular antibiotic-resistant microorganisms (ARM), are of increasing interest. An especially promising method could be a water treatment by physical plasma which provides charged particles, electric fields, UV-radiation, and reactive species. The latter are foremost responsible for the antimicrobial properties of plasma. Thus, with plasma it might be possible to reduce the amount of ARM and to establish this technology as additional treatment stage for wastewater remediation. However, the impact of plasma on microorganisms beyond a mere inactivation was analyzed in more detail by a proteomic approach. Therefore, Escherichia coli GW-AmxH19, isolated from hospital wastewater in Germany, was used. The bacterial solution was treated by a plasma discharge ignited between each of four pins and the liquid surface. The growth of E. coli and the pH-value decreased during plasma treatment in comparison with the untreated control. Proteome and antibiotic resistance profile were analyzed. Concentrations of nitrite and nitrate were determined as long-lived indicative products of a transient chemistry associated with reactive nitrogen species (RNS). Conversely, hydrogen peroxide served as indicator for reactive oxygen species (ROS). Proteome analyses revealed an oxidative stress response as a result of plasma-generated RNS and ROS as well as a pH-balancing reaction as key responses to plasma treatment. Both, the generation of reactive species and a decreased pH-value is characteristic for plasma-treated solutions. The plasma-mediated changes of the proteome are discussed also in comparison with the Gram-positive bacterium Bacillus subtilis. Furthermore, no effect of the plasma treatment, on the antibiotic resistance of E. coli, was determined under the chosen conditions. The knowledge about the physiological changes of ARM in response to plasma is of fundamental interest to understand the molecular basis for the inactivation. This will be important for the further development and implementation of plasma in wastewater remediation.

Paper-based sensor with electro-modified chitosan/silver nanoparticles for rapid and sensitive nitrite detection

The presence of high concentration of nitrite in natural environment and food can be harmful to water ecosystems and human health. It is of great significance to develop a reliable detection method for nitrite. In this work, a modified paper sensor (CS/AgNPs-PE) was fabricated by electrodepositing chitosan (CS) and electrochemically reducing silver nanoparticles (AgNPs) onto an oxidized graphene/cellulose/carbon fiber composite paper sensor. The successful loading of chitosan and AgNPs enhances the electrocatalytic activity of the sensor, improving the detection performance of nitrite. The electrochemical process of nitrite on the surface of the CS/AgNPs-PE was proven to be a diffusion-controlled irreversible reaction. Cyclic voltammetry and differential pulse voltammetry (DPV) were used to quantitatively analyze nitrite. A low detection limit of 7.9 × 10−7 mol L−1 can be obtained by DPV under a wide nitrite detection range of 4.0–1000 µM. CS/AgNPs-PE sensor exhibited good repeatability and selectivity, and it could be used to detect nitrite in tap water and ham samples. These results suggest that the CS/AgNPs-PE sensor is of great potential for nitrite sensing in real samples.

Targeted Metabolomics Highlights Dramatic Antioxidant Depletion, Increased Oxidative/Nitrosative Stress and Altered Purine and Pyrimidine Concentrations in Serum of Primary Myelofibrosis Patients.

To date, little is known concerning the circulating levels of biochemically relevant metabolites (antioxidants, oxidative/nitrosative stress biomarkers, purines, and pyrimidines) in patients with primary myelofibrosis (PMF), a rare form of myeloproliferative tumor causing a dramatic decrease in erythropoiesis and angiogenesis. In this study, using a targeted metabolomic approach, serum samples of 22 PMF patients and of 22 control healthy donors were analyzed to quantify the circulating concentrations of hypoxanthine, xanthine, uric acid (as representative purines), uracil, β-pseudouridine, uridine (as representative pyrimidines), reduced glutathione (GSH), ascorbic acid (as two of the main water-soluble antioxidants), malondialdehyde, nitrite, nitrate (as oxidative/nitrosative stress biomarkers) and creatinine, using well-established HPLC method for their determination. Results showed that PMF patients have dramatic depletions of both ascorbic acid and GSH (37.3- and 3.81-times lower circulating concentrations, respectively, than those recorded in healthy controls, p < 0.0001), accompanied by significant increases in malondialdehyde (MDA) and nitrite + nitrate (4.73- and 1.66-times higher circulating concentrations, respectively, than those recorded in healthy controls, p < 0.0001). Additionally, PMF patients have remarkable alterations of circulating purines, pyrimidines, and creatinine, suggesting potential mitochondrial dysfunctions causing energy metabolism imbalance and consequent increases in these cell energy-related compounds. Overall, these results, besides evidencing previously unknown serum metabolic alterations in PMF patients, suggest that the determination of serum levels of the aforementioned compounds may be useful to evaluate PMF patients on hospital admission for adjunctive therapies aimed at recovering their correct antioxidant status, as well as to monitor patients' status and potential pharmacological treatments.

An Electroanalytical Enzymeless α-Fe2O3-ZnO Hybrid Nanostructure-Based Sensor for Sensitive Quantification of Nitrite Ions.

Nitrite monitoring serves as a fundamental practice for protecting public health, preserving environmental quality, ensuring food safety, maintaining industrial safety standards, and optimizing agricultural practices. Although many nitrite sensing methods have been recently developed, the quantification of nitrite remains challenging due to sensitivity and selectivity limitations. In this context, we present the fabrication of enzymeless iron oxide nanoparticle-modified zinc oxide nanorod (α-Fe2O3-ZnO NR) hybrid nanostructure-based nitrite sensor fabrication. The α-Fe2O3-ZnO NR hybrid nanostructure was synthesized using a two-step hydrothermal method and characterized in detail utilizing x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). These analyses confirm the successful synthesis of an α-Fe2O3-ZnO NR hybrid nanostructure, highlighting its morphology, purity, crystallinity, and elemental constituents. The α-Fe2O3-ZnO NR hybrid nanostructure was used to modify the SPCE (screen-printed carbon electrode) for enzymeless nitrite sensor fabrication. The voltammetric methods (i.e., cyclic voltammetry (CV) and differential pulse voltammetry (DPV)) were employed to explore the electrochemical characteristics of α-Fe2O3-ZnO NR/SPCE sensors for nitrite. Upon examination of the sensor's electrochemical behavior across a range of nitrite concentrations (0 to 500 µM), it is evident that the α-Fe2O3-ZnO NR hybrid nanostructure shows an increased response with increasing nitrite concentration. The sensor demonstrates a linear response to nitrite concentrations up to 400 µM, a remarkable sensitivity of 18.10 µA µM-1 cm-2, and a notably low detection threshold of 0.16 µM. Furthermore, its exceptional selectivity, stability, and reproducibility make it an ideal tool for accurately measuring nitrite levels in serum, yielding reliable outcomes. This advancement heralds a significant step forward in the field of environmental monitoring, offering a potent solution for the precise assessment of nitrite pollution.

Metabolomic reveals the responses of sludge properties and microbial communities to high nitrite stress in denitrifying phosphorus removal systems

Nitrite, as an electron acceptor, plays a good role in denitrifying phosphorus removal (DPR); however, high nitrite concentration has adverse affects on sludge performance. We investigated the precise mechanisms of responses of sludge to high nitrite stress, including surface characteristics, intracellular and extracellular components, microbial and metabolic responses. When the nitrite stress reached 90 mg/L, the sludge settling performance was improved, but the activated sludge was aging. FTIR and XPS analysis revealed a significant increase in the hydrophobicity of the sludge, resulting in improve settling performance. However, the intracellular carbon sources synthesis was inhibited. In addition, the components in the tightly bound extracellular polymeric substances (TB-EPS) of sludge were significantly reduced and indicated the disturb of metabolism. Notably, Exiguobacterium emerged as a new genus when face high nitrite stress that could maintaining survival in hostile environments. Moreover, metabolomic analysis demonstrated strong biological response to nitrite stress further supported above results that include the inhibited of carbohydrate and amino acid metabolism. More importantly, some lipids (PS, PA, LysoPA, LysoPC and LysoPE) were significantly upregulated that related enhanced membrane lipid remodeling. The comprehensive analyses provide novel insights into the high nitrite stress responses mechanisms in activated sludge systems.

Dietary Nitrate Metabolism in Porcine Ocular Tissues Determined Using 15N-Labeled Sodium Nitrate Supplementation.

Nitrate (NO3-) obtained from the diet is converted to nitrite (NO2-) and subsequently to nitric oxide (NO) within the body. Previously, we showed that porcine eye components contain substantial amounts of nitrate and nitrite that are similar to those in blood. Notably, cornea and sclera exhibited the capability to reduce nitrate to nitrite. To gain deeper insights into nitrate metabolism in porcine eyes, our current study involved feeding pigs either NaCl or Na15NO3 and assessing the levels of total and 15N-labeled NO3-/NO2- in various ocular tissues. Three hours after Na15NO3 ingestion, a marked increase in 15NO3- and 15NO2- was observed in all parts of the eye; in particular, the aqueous and vitreous humor showed a high 15NO3- enrichment (77.5 and 74.5%, respectively), similar to that of plasma (77.1%) and showed an even higher 15NO2- enrichment (39.9 and 35.3%, respectively) than that of plasma (19.8%). The total amounts of NO3- and NO2- exhibited patterns consistent with those observed in 15N analysis. Next, to investigate whether nitrate or nitrite accumulate proportionally after multiple nitrate treatments, we measured nitrate and nitrite contents after supplementing pigs with Na15NO3 for five consecutive days. In both 15N-labeled and total nitrate and nitrite analysis, we did not observe further accumulation of these ions after multiple treatments, compared to a single treatment. These findings suggest that dietary nitrate supplementation exerts a significant influence on nitrate and nitrite levels and potentially NO levels in the eye and opens up the possibility for the therapeutic use of dietary nitrate/nitrite to enhance or restore NO levels in ocular tissues.

Impact of the reduction or replacement of NaCl during production and ripening of raw cured pork and turkey sausages

There are health concerns with regard to the consumption of sodium. Excessive consumption of sodium is suspected to cause high blood pressure, among other things. Therefore, sodium should be reduced or replaced during the production of food. In the present study, in the first part, raw fermented sausages from pork and turkey meat, produced with reduced NaCl concentrations, were investigated. In a second part, the salts, potassium chloride, magnesium chloride, and calcium chloride were added to the sausages, replacing 50% of NaCl. To elucidate, if the reduction or replacement influences the quality of the sausages, physicochemical and microbiological parameters of the products were analyzed. The data show that a reduction of sodium chloride partly influences the hardness and water activity results of raw fermented sausages, made from pork and turkey meat, the redness and nitrite content of the pork sausages, and the ripening losses and total viable counts of the turkey products. Raw fermented sausages with potassium, magnesium, and calcium as partial substitutes for sodium had differing water activity, pH, hardness, and microbiological results using pork and differing pH, hardness, and microbiological results using turkey meat. A bactericidal effect was observed in raw fermented sausages with calcium chloride in inoculation tests with Listeria monocytogenes due to the pH reduction due to calcium. The results indicate that reduction and replacement of NaCl can influence the final products. Therefore, the producers should carefully evaluate before alteration the NaCl content, if this change influences the product acceptability.