Nitrite Concentrations Research Articles

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.

Fluxes of nitrogen and phosphorus in fouling communities on artificial offshore structures

The number of offshore artificial structures in the North Sea is continuously increasing. Apart from the structures that have been added to the marine environment accidentally (e.g., shipwrecks), structures are also deliberately developed to meet the increasing needs for renewable energy. These structures provide habitat for fouling organisms. The fouling communities vary in abundance and composition based on location, depth, and structure age. Most fouling species filter particles from the water column, changing phytoplankton production and affecting larval settlement success, while releasing ammonium that can fuel phytoplankton growth as well as (pseudo)faeces that enriches the seabed, changing local biogeochemical cycles.Our study used in-situ incubation chambers to investigate oxygen, nitrogen, and phosphate fluxes associated with fouling organisms to improve understanding of these changes in biogeochemical cycles. Divers used incubation chambers (domes) on shipwrecks in the southern North Sea where over 55 years mature fouling communities have established. A series of water samples was collected from each dome during deployment to measure the change in concentration of ammonium, nitrite, nitrate, and phosphate. All fauna enclosed in the domes was collected after each measurement for further analysis.The full macrofauna dataset contained 65 unique species on 4 shipwrecks (25 to 50 species per sample). Abundance ranged from 2187 to 59,427 individuals per sample (683 cm2). On average, a decrease in oxygen concentration of 126 μmol/g ash free dry weight/h was found. The sequential water samples also showed clear changes in nutrient concentration with time in all incubations. The largest changes were observed with high fouling community abundances and biomass. Ammonium, nitrite, and phosphate always increased, with 1.5-to-5-fold increases from start to end of the incubation, while for nitrate both an efflux and influx were measured. Oxygen decreased in all incubations. Mean fluxes (all in μmol per m2 per hour with standard error) were significant for ammonium (945 ± 300), nitrite (80 ± 30), phosphate (61 ± 8), and oxygen (−11,794 ± 3289), but not for nitrate (−206 ± 122). Per gram AFDW, only ammonium (12.7 ± 3.5) and oxygen (−126 ± 48) had fluxes that differed significantly from zero.Compared to average seabed (sandy bottom) oxygen demand and community fluxes from previous studies, the observed fluxes were high. Our findings resembled those from temperate biogenic reef studies. Further data collection across a larger spatial and temporal scale is needed to fully understand offshore structure effects on marine environments.

Ready-to-Use Vegetable Salads: Physicochemical and Microbiological Evaluation

Ready-to-use vegetable salads are minimally processed products, rich in antioxidants, but are associated with a high microbiological risk and possibly, in some cases, with a high content of nitrites. The purpose of this study was to investigate the physicochemical and microbiological properties of different ready-to-use vegetable salad assortments on the Romanian market. Seventeen types of salad vegetables were evaluated for the determination of water activity, antioxidant activity and nitrite concentration and tested for the presence of microorganisms. The water activity of the samples varied from 0.873 to 0.933, and the IC50 values were between 1.31 ± 0.02 and 5.43 ± 0.04 µg/mL. Nitrites were present in all samples investigated (ranging from 290.6 to 3041.17 mg/kg). Staphylococci and Enterobacteriaceae were detected in 35.3% and 70.5% of the samples. Furthermore, 17.6% of the salads were contaminated with Escherichia coli, and Listeria was detected in 29.4% of the samples. Salmonella was detected in only one sample, and Faecal streptococci were not present in any of the samples. The results indicated high nitrite values and also revealed pathogens’ presence. Producers should make more efforts to lower microbial contamination, while maximum limits for nitrites in vegetables should be set based on the impact on human health.

Enhancing the relative abundance of comammox nitrospira in ammonia oxidizer community decreases N2O emission in nitrification exponentially

Comammox Nitrospira and canonical ammonia-oxidizing bacteria (cAOB) generally coexist in activated sludge. In present study, the effect of comammox Nitrospira on N2O production during nitrification of activated sludge was investigated. Comammox Nitrospira and cAOB were separately enriched in two nitrifying reactors, with respective relative abundance of approximately 98% in ammonia oxidizer community. The N2O emission factor (EF) of nitrification in comammox Nitrospira dominated reactor was 0.35%, consistently lower than that (2.2%) in cAOB dominated reactor. When increasing the relative abundance of comammox Nitrospira in ammonia oxidizer community, the N2O EF of nitrification decreased exponentially, which suggested that comammox Nitrospira not only decreased N2O production directly but also might have reduced N2O yield by cAOB. When cAOB dominated the ammonia oxidizer community of sludge, decreasing pH to 6.3, lowering DO to less than 0.5 mg/L, and increasing nitrite concentration enhanced N2O EF dramatically. When comammox Nitrospira became the dominant ammonia oxidizer, however, the N2O EF correlated to nitrite insignificantly and a low DO of 0.2 mg/L and weakly acidic pH (6.3) decreased N2O EF by approximately 70% and 60%, respectively. These results imply that enhancing the relative abundance of comammox Nitrospira in sludge is an effective way to reducing N2O emissions and can also offset the promoting effects of acidic pH, low DO, and high nitrite concentration on N2O production during nitrification.

Antioxidative and anti-inflammatory effects of taxifolin in H2O2-induced oxidative stress in HTR-8/SVneo trophoblast cell line

Oxidative stress has been implicated in numerous pregnancy-related disorders. Biologically active plant secondary metabolites, which are present in everyday diet, could prove effective therapeutic agents in preventing these disorders. This study evaluated effects of taxifolin (dihydroquercetin) on ROS production, markers of oxidative damage to lipids and proteins, activity of antioxidant enzymes and production of pro-inflammatory cytokines in H2O2-induced oxidative stress in trophoblast HTR-8/SVneo cells. Taxifolin in 10 µM and 100 µM concentrations attenuated oxidative damage to lipids and proteins, as evidenced by a decrease in MDA content, extracellular LDH activity, carbonyl groups and nitrite contents. A reduction in the activity of antioxidant enzymes SOD, CAT and GPx in cells pre-treated with taxifolin, prior to H2O2 exposure, was also observed, along with a reduction in intracellular ROS production. Both evaluated concentrations of taxifolin showed anti-inflammatory activity in trophoblast cells, by reducing production of pro-inflammatory cytokines IL-1β and IL-6. In this model of H2O2-induced oxidative stress, taxifolin showed marked antioxidative and anti-inflammatory activities in trophoblast cells, adding further evidence of its protective effects and showing potential as a therapeutic agent in preventing adverse pregnancy outcomes.

Spatial and temporal distribution of nutrients in the Ciliwung River, DKI Jakarta

The Ciliwung River, one of the largest rivers to run through Jakarta, is particularly important for its water quality because it travels through the city’s center and several settlements, highly populated housing areas, and slums. The growth of algae and macrophytes, or aquatic plants, is dependent on the nutrients in the streams. These plants serve as major food sources for fish and other small invertebrates. This study aimed to describe the distribution of nutrients (ammonia, nitrite, nitrate, total nitrogen, and total phosphate) in the Ciliwung River, DKI Jakarta, in terms of both space and time. Water quality was monitored under rainy (February and June 2021) and dry (August and September 2021) conditions. The research area, which included 18 observation stations, was situated in the DKI Jakarta sector along the Ciliwung River. Geographically, all river regions’ concentrations of total nitrogen, nitrate, and total phosphate exceeded the quality criteria; however, ammonia and nitrite tended to be high and did not meet norms across the Ciliwung River area, DKI Jakarta. While ammonia concentrations were greater during the dry season and nitrate concentrations were higher during the rainy season, there was a temporary difference in the concentrations of nitrite, total nitrogen, and total phosphate between the seasons.

Effect of electrode in UASB-MFC reactor for nitrogen removal under anammox condition and its microbial community profile

Nitrogen removal through anammox is well-known for its low cost and less CO2 emissions, in this process ammonium converted into nitrogen gas with the help of anammox. It is hypothesized that the presence of electrodes in upflow anaerobic sludge blanket-microbial fuel cell (UASB-MFC) might increase nitrogen removal. In order to check this, two experimental setup were used to remove ammonium with electrode (UASB-MFC) and without electrode (UASB), under anammox condition. Different parameters were analyzed including nitrate, nitrite, total nitrogen and voltage. After 164 days, the NH4+ concentration in effluent was 3.20 mg/L and 4.23 mg/L, total inorganic nitrogen was 11.9 mg/L and 8.45 mg/L in UASB and UASB-MFC effluent respectively. Bacterial growth rate was calculated through biokinetic modelling, indicating anammox growth rate 0.00294 g VSS/m3.d in UASB-MFC with maximum voltage production of 774 mV. Metagenomic study was performed through 16 S rRNA genome sequencing showed, Firmicutes phylum was high in both reactors, while Planctomycetes, abundance 2.8% showing anammox growth achievement only in UASB-MFC. Lower concentration of nitrate, nitrite and total inorganic nitrogen were found in the UASB-MFC effluent which suggested the higher conversion of ammonium into nitrogen gas. It is concluded that the presence of an electrode oxidizes more nitrogen; hence total nitrogen was removed much more than in the absence of an electrode.

Comparing methanol and glycerol as carbon sources for mainstream partial denitrification/anammox in an IFAS process.

This study explored the implementation of mainstream partial denitrification with anammox (PdNA) in the second anoxic zone of a wastewater treatment process in an integrated fixed film activated sludge (IFAS) configuration. A pilot study was conducted to compare the use of methanol and glycerol as external carbon sources for an IFAS PdNA startup, with a goal to optimize nitrogen removal while minimizing carbon usage. The study also investigated the establishment of anammox bacteria on virgin carriers in IFAS reactors without the use of seeding, and it is the first IFAS PdNA startup to use methanol as an external carbon source. The establishment of anammox bacteria was confirmed in both reactors 102 days after startup. Although the glycerol-fed reactor achieved a higher steady-state maximum ammonia removal rate because of anammox bacteria (1.6 ±0.3g/m2/day) in comparison with the methanol-fed reactor (1.2±0.2g/m2/day), both the glycerol- and methanol-fed reactors achieved similar average in situ ammonia removal rates of 0.39 ±0.2g/m2/day and 0.40 ±0.2g/m2/day, respectively. Additionally, when the upstream ammonia versus NOx (AvN) control system maintained an ideal ratio of 0.40-0.50 g/g, the methanol-fed reactor attained a lower average effluent TIN concentration (3.50 ±1.2mg/L) than the glycerol-fed reactor (4.43 ±1.6mg/L), which was prone to elevated nitrite concentrations in the effluent. Overall, this research highlights the potential for PdNA in IFAS configurations as an efficient and cost-saving method for wastewater treatment, with methanol as a viable carbon source for the establishment of anammox bacteria. PRACTITIONER POINTS: Methanol is an effective external carbon source for an anammox startup that avoids the need for costly alternative carbon sources. The methanol-fed reactor demonstrated higher TIN removal compared with the glycerol-fed reactor because of less overproduction of nitrite. Anammox bacteria was established in an IFAS reactor without seeding and used internally stored carbon to reduce external carbon addition. Controlling the influent ammonia versus NOx (AvN) ratio between 0.40 and 0.50 g/g allowed for low and stable TIN effluent conditions.

Arsenic Exposure-Related Hypertension in Bangladesh and Reduced Circulating Nitric Oxide Bioavailability.

Hypertension is a major cause of death worldwide. Although arsenic exposure has been associated with the risk of hypertension, this association appears nonuniform due to inconsistent results from studies conducted in different populations. Moreover, hypertension is a complex condition with multiple underlying mechanisms and factors. One factor is impaired production and bioavailability of vascular nitric oxide (NO). However, the implications of the effects of arsenic exposure on circulating NO and its association with hypertension in humans are largely unknown. We investigated the dose-response relationship between arsenic exposure and hypertension with vascular NO levels as a potential mediator of arsenic-related hypertension in individuals exposed to a broad range of arsenic. A total of 828 participants were recruited from low- and high-arsenic exposure areas in Bangladesh. Participants' drinking water, hair, and nail arsenic concentrations were measured by inductively coupled plasma mass spectroscopy. Hypertension was defined as a systolic blood pressure (SBP) value of and a diastolic (DBP) value of . Serum NO levels reflected by total serum nitrite concentrations were measured by immunoassay. A formal causal mediation analysis was used to assess NO as a mediator of the association between arsenic level and hypertension. Increasing concentrations of arsenic measured in drinking water, hair, and nails were associated with the increasing levels of SBP and DBP. The odds of hypertension were dose-dependently increased by arsenic even in participants exposed to relatively low to moderate levels () of water arsenic [odds ratios (ORs) and 95% confidence intervals (CIs): 2.87 (95% CI: 1.28, 6.44), 2.67 (95% CI: 1.27, 5.60), and 5.04 (95% CI: 2.71, 9.35) for the , , and groups, respectively]. Causal mediation analysis showed a significant mediating effect of NO on arsenic-related SBP, DBP, and hypertension. Increasing exposure to arsenic was associated with increasing odds of hypertension. The association was mediated through the reduction of vascular NO bioavailability, suggesting that impaired NO bioavailability was a plausible underlying mechanism of arsenic-induced hypertension in this Bangladeshi population. https://doi.org/10.1289/EHP13018.

Nutrient regimes in a semi-enclosed marginal sea: The Persian Gulf

ABSTRACT In this study, the results of hydrochemical measurement aboard the RV Kavoshgar Khalij Fars in the Persian Gulf (PG) in September 2018, May, and November 2019 are discussed. Nitrate, nitrite, ammonium, phosphate, and silicate concentrations, salinity, temperature, dissolved oxygen, and pH in the water column of a 1000-km transect in the PG were studied to determine the present status of nutrient regimes of this region. Nitrate, phosphate, and silicate were more concentrated at the bottom layer and showed a maximum just below the thermocline in summer and autumn. Seasonal distribution of nutrient ratios (N:P, N:Si, Si:P) indicates P limitation in autumn, N limitation in spring, P limitation and poor Si in summer throughout the upper layer. The results of this study do not infer eutrophication in the upper layer of the PG waters in autumn and summer.

Nitrous Oxide Emissions from Nitritation Reactors under Hypersaline Conditions

This study focuses on nitrous oxide (N2O) emissions during hypersaline (4 % salinity) nitritation in continuously fed and mixed fixed bed reactors. In the presence of high concentrations of nitrite and ammonium, the percent yield of N2O emissions from ammonium removed decreased with increasing dissolved oxygen (DO). However, N2O production continued even at a high DO of 15 mg/L. Bulk ammonium concentration (not ammonia) was found to be the main controlling factor for N2O emissions under high and low DO during both nitritation and nitrification. Reducing bulk ammonium concentrations below 1 mg N/L in the nitritation reactor under both high and low DO conditions resulted in a reduction of N2O emissions of approximately 90 %. Under full nitrification and low DO, reducing nitrite concentrations below 0.3 mg N/L resulted in a 60 % reduction in N2O emissions. Similar results were observed in a low salinity reactor.

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.

Enhancing quality control in emulsion-type sausage production: Predicting chemical composition of intact samples with near infrared spectroscopy

This research actively explores the potential of near infrared spectroscopy (NIR) for analyzing the chemical composition of emulsion-type sausages, focusing on critical factors like residual nitrite, moisture, protein, and fat content. To establish robust and generalizable models, we utilized a dataset of 100 experimentally prepared sausages encompassing a wide range of pork back fat replacement levels (5%, 15%, 30%, 45%, and 60%) and added sodium nitrite amounts (0, 80, 125, 250, and 375 ppm). An external validation set of 20 commercially sourced sausages further assessed the model’s real-world applicability. Partial least squares (PLS) regression calibration models with multiplicative scatter correction (MSC) pre-treatment demonstrated impressive accuracy for moisture (RMSECV = 0.57%, RPD = 9.8), fat (RMSECV = 1.17%, RPD = 9.5), and protein (RMSECV = 0.30%, RPD = 7.6). While residual nitrite prediction presented challenges due to its inherent complexity, the external validation yielded a competitive root mean square error of prediction (RMSEP) of 12.02 ppm, surpassing the average performance reported in similar studies (RMSEP ∼15 ppm) by 3 ppm. Importantly, sample homogenization did not significantly affect parameter prediction, highlighting the robustness of the NIR-based approach. These findings suggest that NIR spectroscopy, with its non-destructive, rapid, and cost-effective nature, could provide valuable tools for quality control and monitoring in the emulsion-type sausage industry. More importantly, improved nitrite prediction could pave the way for enhanced precision and control in sausage production, ultimately contributing to improved food safety and sustainability.

Исследование химического состава воды подземного источника, расположенного на пойменном участке реки Малка в нижнем течении

The analysis of an undergroundsourcewaterchemicalcomposition located inthe floodplain oftheMalka River,the largestriver flowing through the territory of the Kabardino-Balkarian Republic, is presented. Data on the quantitativecontent of the groundwater ion-saltcomposition components serve as indicators to identify background concentrations of pollutants in river waters. The observation results of the intra-annual dynamics of flow, temperature, transparency, pH, mineralization, hardness, permanent oxidability, concentrations of carbonates, bicarbonates, chlorides, sulfates, nitrites, nitrates, and total iron are presented. The qualitative trace element composition has been determined. The results of sanitary and microbiological analysis are presented. The theoretical analysis allows us to conclude that the chemical composition of the water under study follows general patterns. The constancy of the underground source waters temperature indicates the deep occurrence of aquifers. The chemical composition of water is determined by the composition of minerals and rocks, which it comes into contact with, remains almost constant throughout the year and, to a small extent, depends on climatic conditions on the surface. Data on the concentration of components of the ion-salt composition and microflora characterizing the water quality of an underground source were obtained. The water of an underground source refers to neutral, fresh, medium hardness, bicarbonate waters that are not contaminated with pathogenic microflora.

Water Quality and Growth Performance of Nile Tilapia (Oreochromis niloticus), Chia (Salvia hispanica) and Lemon Grass (Cymbopogon citratus) in a Media-based Aquaponics System

High ammonia levels in enclosed fish production systems negatively impact fish growth and hinder optimum production. The objective of this study was to evaluate the (i) biofiltration potential of chia (Salvia hispanica) and lemon grass (Cymbopogon citratus) (ii) the influence of the plant filters on water quality and fish growth in an aquaponic system. Treatments included a control-without plants, S. hispanica, and C. citratus aquaponic systems. The study was conducted for 3 months in Aqualife fish farm, Machakos, Kenya. Water quality parameters, growth performance of fish and plants were monitored during the experiment. The plant treatments significantly (P< 0.05) reduced ammonia levels compared to the control (0.07 ± 0.17 mgL-1). There was a remarkable 32-fold decrease in ammonia compared to the hydroponic inlet. Planted aquaponic systems significantly (P < 0.05) reduced nitrite and nitrate concentrations compared to the control, indicating effective nutrient cycling and improved water quality. Notably, both S. hispanica (115. 5 ± 3.2 g) and C. citratus (130.3 ± 3.32 g) systems significantly (P < 0.05) boosted the growth performance of O. niloticus compared to the control (113. 5 ± 3.2 g). C. citratus performed better (450 ± 9.17 g) than S. hispanica (217.6 ± 2.52 g). These findings highlight the potential of the plants as sustainable and efficient biofilters, enhancing overall aquaponic system performance and contributing to a more productive and environmentally friendly approach to food production.

Metagenomic Insight into the Effect of Probiotics on Nitrogen Cycle in the Coilia nasus Aquaculture Pond Water.

Recently, probiotics have been widely applied for the in situ remediation of aquatic water. Numerous studies have proved that probiotics can regulate water quality by improving the microbial community. Nitrogen cycling, induced by microorganisms, is a crucial process for maintaining the balance of the aquatic ecosystem. Nevertheless, the underlying mechanisms by which probiotics enhance water quality in aquatic systems remain poorly understood. To explore the water quality indicators and their correlation with nitrogen cycling-related functional genes, metagenomic analysis of element cycling was performed to identify nitrogen cycling-related functional genes in Coilia nasus aquatic water between the control group (C) and the groups supplemented with probiotics in feed (PF) or water (PW). The results showed that adding probiotics to the aquatic water could reduce the concentrations of ammonia nitrogen (NH4+-N), nitrite (NO2--N), and total nitrogen (TN) in the water. Community structure analysis revealed that the relative abundance of Verrucomicrobiota was increased from 30 d to 120 d (2.61% to 6.35%) in the PW group, while the relative abundance of Cyanobacteria was decreased from 30 d to 120 d (5.66% to 1.77%). We constructed a nitrogen cycling pathway diagram for C. nasus aquaculture ponds. The nitrogen cycle functional analysis showed that adding probiotics to the water could increase the relative abundance of the amoC_B and hao (Nitrification pathways) and the nirS and nosZ (Denitrification pathways). Correlation analysis revealed that NH4+-N was significantly negatively correlated with Limnohabitans, Sediminibacterium, and Algoriphagus, while NO2--N was significantly negatively correlated with Roseomonas and Rubrivivax. Our study demonstrated that adding probiotics to the water can promote nitrogen element conversion and migration, facilitate nitrogen cycling, benefit ecological environment protection, and remove nitrogen-containing compounds in aquaculture systems by altering the relative abundance of nitrogen cycling-related functional genes and microorganisms.

Effects of enhanced fermentation with Lactiplantibacillus plantarum WWPC on physicochemical characteristics and flavor profiles of radish paocai and dried-fermented radish

Lactiplantibacillus plantarum, the biomarker that occupied an important position in fermented radish paocai with high quality, was selected and applied as a starter culture to manufacture fermented radishes. Herein, this work developed a method of enhanced fermentation by using L. plantarum WWPC to shorten the fermentation period and improve the flavor and safety of fermented radish products. Particularly, the effect of L. plantarum WWPC on physicochemical characteristics and flavor profiles of liquid-state-based radish paocai and solid-state-based dried-fermented radish was systematically investigated. The results indicated that the enhanced fermentation inoculated with L. plantarum WWPC could accelerate the fermentation process (2 times in radish paocai) and postpone the yellowing of white radish paocai (ΔE>5). Meanwhile, the content of nitrite in radish products diminished with the participation of L. plantarum WWPC. Furthermore, enhanced fermentation with L. plantarum WWPC improved the flavor profiles of white radish paocai, especially lactic acid, oxalic acid, Glu, ocimenol, and trans-4-thujanol. Meanwhile, the predominant flavor substances mainly consisting of Glu, octanal, and 4-methylthio-3-butenyl isothiocyanate were affluent in red dried-fermented radish inoculated with L. plantarum WWPC. The pleasant and abundant taste and aroma of the enhanced fermented radish products possessed further verified the practicality and appropriateness of L. plantarum WWPC for radish fermentation. These findings could contribute to synthetically exploiting and developing radish products with high quality.

THE INFLUENCE OF QUERCETIN ON THE PRODUCTION OF REACTIVE OXYGEN-NITROGEN FORMS IN THE STRUCTURE OF THE INTERSTITIAL SPACE OF RAT TESTICLES WITH LONG-TERM EFFECT OF TRIPTORELIN

Quercetin is a flavonoid commonly found in fruits, vegetables, and seeds. Flavonoids can help prevent cardiovascular diseases, reduce the risk of degenerative brain processes and cancer. Studies have shown that blocking the synthesis of luteinising hormone can lead to oxidative stress in the liver, heart, and salivary glands of rats. The purpose of this study was to assess alterations in the interstitial space of rat testes, identify sources of nitric oxide production, and measure the intensity of oxidative stress in the testes during long-term experimental central blocking of luteinising hormone synthesis by tryptorelin. The study was conducted on 15 sexually mature male white rats. The animals were divided into two groups. The first group (control) received a subcutaneous injection of 0.9% sodium chloride solution. The second group (experimental) received a subcutaneous injection of tryptorelin at a dose of 0.3 mg/kg of active ingredient for 365 days, with simultaneous addition of quercetin to the diet, which was administered orally through a gastric tube three times a day. Total nitric oxide production was assessed by measuring the activity of total NO synthase (gNOS). The activity of gNOS was determined by the increase in nitrite (NO2-) after incubation in Tris-buffered saline. The nitrite concentration was determined using the Gris-Ilosvay reagent at a wavelength of 540 nm. The activity of the inducible (iNOS) and constitutive (cNOS) isoforms was also determined using a selective iNOS inhibitor, aminoguanidine hydrochloride. The production of superoxide anion radical (O2--) was measured by the increase in the formation of diformazan resulting from the reaction of O2-- with nitroblue tetrazolium after incubation in a buffered solution containing sodium hydroxide. The administration of quercetin mitigates the adverse effects of tryptorelin on the structural and functional components of the connective tissue in the rat testes. This effect is observed on day 365 and is characterised by fibrosis and impaired nitric oxide production by constitutive isoforms of NO synthase.

Trypanocidal and Anti-Inflammatory Effects of Three ent-Kaurane Diterpenoids from Gymnocoronis spilanthoides var. subcordata (Asteraceae).

Chagas disease, caused by the protozoan Trypanosoma cruzi, affects 6-7 million people worldwide. The dichloromethane extract obtained from the aerial parts of Gymnocoronis spilanthoides var subcordata showed trypanocidal activity in vitro. The fractionation of the dewaxed organic extract via column chromatography led to the isolation of three diterpenoids: ent-9α,11α-dihydroxy-15-oxo-kaur-16-en-19-oic acid or adenostemmoic acid B, (16R)-ent-11α-hydroxy-15-oxokauran-19-oic acid and ent-11α-hydroxy-15-oxo-kaur-16-en-19-oic acid. These compounds showed IC50 values of 10.6, 15.9 and 4.8 µM against T. cruzi epimastigotes, respectively. When tested against amastigotes, the diterpenoids afforded IC50 values of 6.1, 19.5 and 60.6 µM, respectively. The cytotoxicity of the compounds was tested on mammalian cells using an MTT assay, resulting in CC50s of 321.8, 23.3 and 14.8 µM, respectively. The effect of adenostemmoic acid B on T. cruzi was examined at the ultrastructural level using transmission microscopy. Treatment with 20 μM for 48 h stimulated the formation of abnormal cytosolic membranous structures in the parasite. This compound also showed an anti-inflammatory effect in murine macrophages stimulated with LPS and other TLR agonists. Treatment of macrophages with adenostemmoic acid B was able to reduce TNF secretion and nitric oxide production, while increasing IL-10 production. The combination of adenostemmoic acid B with benznidazole resulted in greater inhibition of NF-kB and a decrease in nitrite concentration. The administration of adenostemmoic acid B to mice infected with trypomastigotes of T. cruzi at the dose of 1 mg/kg/day for five days produced a significant decrease in parasitemia levels and weight loss. Treatment with the association with benznidazole increased the survival time of the animals. In view of these results, adenostemmoic acid B could be considered a promising candidate for further studies in the search for new treatments for Chagas disease.