Ammonia Exposure Research Articles

A highly sensitive and selective ZnO-based ammonia sensor: Fe- doping effect

Abstract This study investigates the gas sensing capabilities of ZnO and Fe-doped ZnO films prepared via a cost-effective spin coating method. The films were characterized optically, structurally, and morphologically. X-ray diffraction revealed good crystal quality with a polycrystalline nature, and wurzite structure, though crystal quality and crystallite size decreased with Fe doping. Optical measurements indicated an increased optical band gap from 3.205 ± 0.002 to 3.220 ± 0.002 eV after Fe doping. Scanning electron microscope images confirmed spherical grainy structures with reduced grain sizes after Fe doping. Gas sensing measurements at room temperature (RT) at an exposure of vapors of various toxic chemicals (acetone, ethanol, propanol, methanol, and ammonia), demonstrated a highly selective nature of ZnO and Fe-ZnO towards the ammonia. The Fe-doping into ZnO improved the ammonia sensing capability of ZnO film. The Fe-ZnO film exhibited a gas response of 388.8 ± 5.5 at 400 ppm ammonia exposure, which was nearly 10 times larger than that of ZnO film with a response/recovery time of 22/51 s, good stability, and good repeatability. The Fe-ZnO film’s higher response is attributed to its smaller grain sizes and surplus of charge carriers after Fe doping which promote the adsorption of extra oxygen ions onto the film’s surface and the subsequent interaction between the adsorbed oxygen ions ammonia molecules. It could detect up to the lower limit of 1 ppm ammonia with a response of 24.2 ± 0.9, which is better than the previous reports. These results reveal the Fe-ZnO film as a viable material for developing a cost-effective and efficient ammonia sensor at room temperature.

Ammonia gas sensors based on multi-wall carbon nanofiber field effect transistors by using gate modulation

Ammonia gas sensors play a critical role in environmental monitoring and healthcare applications due to the harmful effects of ammonia exposure. In this study, I present a novel approach to ammonia detection using field-effect transistors (FETs) based on Multi-Wall Carbon Nanofibers (MWCNFs), known for their outstanding electrical properties. I fabricate and characterize MWCNF-FET sensors, utilizing interdigitated Source-Drain electrodes directly deposited onto aligned semiconducting MWCNFs. By systematically investigating the effect of gate bias on sensor performance, I demonstrate that applying a positive gate voltage enhances the sensor's gas response by up to 55 % across varying concentrations of ammonia. Additionally, I show that appropriate gate modulation significantly improves the device's reversibility, ensuring reliable, repeatable measurements. These findings highlight the potential of MWCNF-FETs in developing high-performance, gate-tunable ammonia gas sensors for real-world applications.

Effect of Body Size and Condition Factor on Proximate Composition of Clarias batrachus Under Different Concentration of Ammonia

This study is focused on examining the proximate body composition (water, fats, proteins, and ash) of Clarias batrachus, exposed to different concentrations of ammonia. Fish were kept in different groups with ammonia concentrations of 0 mg/L (T-0), 0.25mg/L (T-I), 0.5mg/L (T-II), 0.75mg/L (T-III), and 1mg/L (T-IV) for 3 months. At the end of the trial, a total of 50 samples of C. batrachus (10 from each treatment group) were taken to analyze the body composition. Mean (±SE) values of water, ash, fat, and protein contents in % wet body weight of C. batrachus were found 77.07±0.80% to 82.23±0.55%, 2.98±0.03%to 3.34±0.17%, 3.90±0.19% to 4.58±0.30% and 10.53±0.40 to 15.36±0.56 in the different studied treatment groups. Water and protein contents were significantly (P<0.05) affected by the exposure of ammonia to C. batrachus. Significantly highest level of protein content was found in the fish group which was not treated with ammonia exposure (T-0). Whereas ash and fat contents showed no significant (P>0.05) difference between the ammonia-treated groups and the control group. Regression analysis showed a clear effect of fish size on water and protein contents in C. batrachus reared in different treatment groups. While ash was found correlated only in T-0 (p<0.001; r=0.939), and fat in T-0 (p<0.001; r=0.929) and T-III (p<0.05; r=0.636). However, the condition factor remained constant with the proximate composition of C. batrachus. This study would be helpful in the measurement of the body composition of fishes with the size of fishes affected by different concentrations of ammonia to analyze the nutritional value of C. batrachus.

Taurine can play a positive role in growth, liver health and resistance to Aeromonas hydrophila of yellow catfish Pelteobagrus fulvidraco exposed to ammonia stress for a long time

Ammonia is an important environmental pollutant that is toxic to most aquatic animals, and nutrient manipulation is an effective regulatory pathway. To assess the influence of taurine supplementation on growth, liver detoxification and anti-bacterial infection of yellow catfish subjected to ammonia exposure for a long time, three experiment diets with different taurine levels (0.50, 1.00, and 2.00 %) were formulated and fed to fish (7.28 ± 0.05) g under three ammonia levels (0.00, 25.00 and 50.00 mg/L total ammonia nitrogen) for 56 days. The results showed that hepatic glycogen and whole-body protein contents were reduced, suggesting that energy deficiency caused by ammonia poisoning plays an important role in growth inhibition; elevated serum alanine aminotransferase and aspartate aminotransferase levels suggest liver injury, which may be caused by oxidative stress (decreased activities of superoxide dismutase and catalase, and expressions of SOD and CAT) and inflammation (increased contents of tumor necrosis factor α, interleukin 1 and interleukin 8, and expressions of TNF α, IL 1 and IL8), analysis of tissue sections further confirmed this finding. Furthermore, after injection with Aeromonas hydrophila, cumulative mortality increased proportionally with the rise in ammonia levels, the observed decrease in serum complements C3, C4, immunoglobulin M, and antibody titer contents emerged as a crucial factor contributing to the decreased disease resistance. The exogenous taurine was found to alleviate the negative impact of the above-mentioned ammonia poisoning. This study provides valuable insights into the mechanism of ammonia-induced aquatic toxicology in fish.

Ammonia exposure impairs bone mineralization in zebrafish (Danio rerio) larvae

Ammonia is a major pollutant of freshwater environments. Previous studies have indicated that ammonia exposure adversely affects the physiology of freshwater fish. However, its effect on bone mineralization in freshwater fish larvae remains unclear. In this study, zebrafish larvae were used as a model to investigate the effects of different ammonia levels (0, 2.5, 5, and 10 mM NH4Cl) on the survival rate, body length, and bone mineralization of fish. The survival rate of zebrafish embryos exposed to different NH4Cl concentrations for 8 days was not affected. In contrast, the body length and bone mineralization of zebrafish larvae at 8 days post fertilization (dpf) were significantly reduced at 5 and 10 mM NH4Cl exposure. Further investigations revealed that ammonia exposure decreased the mRNA expression of osteoblast-related genes and increased that of osteoclast-related genes. Additionally, exposure to 5 mM and 10 mM NH4Cl induced the production of reactive oxygen species (ROS). 10 mM—but not 5 mM—NH4Cl exposure reduced the calcium and phosphorus content in 8 dpf zebrafish larvae. In conclusion, ammonia exposure induces bone resorption, while decreasing the calcium and phosphorus content of the whole body and bone formation, resulting in impaired bone mineralization in fish larvae.

Various effects of feeding level on ammonia tolerance in Carassius auratus under different ammonia exposure stress and the underlying mechanisms

Elevated ammonia levels in aquaculture systems could reduce fish growth and survival rates and produce a range of physiological problems. Ammonia toxicity in aquatic environments was regulated by various factors. Feeding was usually reported to help in the detoxification of fish, thereby increasing their capacity to tolerate ammonia nitrogen. However, the impact of different feeding amounts on fish in relation to ammonia exposure stress remains to be determined. To determine how feeding levels affected fish's responses to different ammonia nitrogen concentrations, two acute toxicity experiments were conducted with Carassius auratus gibelio, the major strain of gibel carp in aquaculture systems in China. In Test I, fed Carassius auratus gibelio (3 % body weight) showed a higher survival rate under a specific ammonia exposure stress. 96-h LC50 of NH3-N to 3 %F gibel carp was 1.1 times greater than that for NF (no feeding). In Test II, all fed groups (2 %F and 4 %F) under low and high ammonia stress exhibited improved ammonia detoxification, evidenced by higher liver GSase, GDH, and glutamine concentrations compared with the NF treatment. Muscle glycogen levels in feeding treatments were higher than those in NF, indicating that fed fish have more energy for ammonia detoxification. While compared with low ammonia treatment (2.70 mg L−1 TAN; NH3 0.06 mg L−1), fish exposed to high ammonia levels (26.03 mg L−1 TAN; NH3 0.57 mg L−1) demonstrated a decrease in food consumption, severe histopathological alterations in their liver, gill, and kidney, and decreased GSase, GDH, and glutamine production in the liver and brain. The results partly supported our hypothesis and suggested that increasing feeding enhances gibel carp's tolerance to ammonia nitrogen. The highest detoxification metabolism was observed under low ammonia stress. While excessive ammonia exposure could inhibit feeding and damage the detoxification organs of fish, and thus reduce the detoxification metabolism of gibel carp.

Activation autophagy enhances ammonia detoxification by boosting urea and glutamine synthesis in yellow catfish (Pelteobagrus fulvidraco)

The study explores how activating autophagy in yellow catfish under chronic ammonia stress (CAS) can boost growth and improve ammonia detoxification, addressing the serious threat of ammonia stress on fish survival and disease susceptibility in aquatic settings. Yellow catfish (Pelteobagrus fulvidraco) weighing 2.35 ± 0.13 g were divided into three groups over an 8-week period: CON group without ammonia exposure, AM group exposed to 50 mg/L total ammonia nitrogen (T-AN), and AM+RAPA group fed diets with 3 mg/100 g rapamycin under 50 mg/L T-AN. Dietary rapamycin (DR) can alleviate growth retardation, liver structural damage, inflammation, apoptosis, decreased detoxification capacity, and reduced survival rate caused by CAS. Additionally, DR can mitigate autophagy inhibition induced by CAS. Metabolomics analysis revealed that activation of autophagy by DR significantly alleviated the glutamate, aspartate n-acetyl-l-glutamate, ornithine, argininosuccinate, and citrulline levels in the liver induced by CAS. This suggests that autophagy activation can supplement these metabolites involved in urea and glutamine synthesis, thereby promoting ammonia detoxification. In conclusion, liver autophagy is a vital mechanism for ammonia detoxification as it facilitates the synthesis of urea and glutamine. Moreover, it offers a theoretical foundation for addressing the negative effects of chronic ammonia exposure in aquaculture.

Fraud-proof methylcellulose-based fish freshness indicator: Reversibility in halochromic sensing of basic volatiles is tailored by ionic strength

Food from animal sources (e.g., fish) represents the food group most likely to disseminate diseases to humans. To prevent food contamination and foodborne illnesses, intelligent packaging has been developed to monitor fish freshness by real-time tracking their physicochemical attributes and informing consumers about their conservation state. In this context, we investigated the influence of ionic strength (IS) provided by CaCl2 on the chromatic response of anthocyanin açai extracts incorporated into methylcellulose (MC) within hydrocolloid-based colorimetric sensors for monitoring the freshness of Lambari fish. The color sensitivity of the sensors was modulated by IS in the presence of NH3 volatile and/or TVB-N. Increasing IS led to a plasticizing effect in the MC matrix, which influenced the chromatic properties of anthocyanin in the presence of NH3 and/or TVB-N. The perception of distinct colors by untrained eyes improved from 10 min with the control sensor to 2.5 min for sensors with IS >50 mM. Adjusting the IS to 500 mM with LiCl, CaCl2, or MgCl2 resulted in gray-green, blue, or moss-green colors, respectively, diverging from the control sensor's color (pink and gray) after 10 min of ammonia exposure, confirming salt-induced copigmentation. Color irreversibility in the sensors was achieved when the IS exceeded 250 mM. Through principal component analysis, we statistically validate the efficacy of the sensor in assessing the freshness of Lambari fish. The sensor maintained its color-change capability even after 60 d of storage and was able to classify Lambari fish freshness according to Brazilian and European standards. This study elucidates the interrelation between the structures and properties of natural compounds such as MC, anthocyanin, and CaCl2, providing a method to control the chromatic properties of sensors intended to monitor food quality, safety, and shelf-life.

Ammonia Exposure Based on the Length of Work to Lung Function Abnormalities Among Traditional Scavengers

Ammonia Exposure Based on the Length of Work to Lung Function Abnormalities Among Traditional Scavengers

Ecological risks of high-ammonia environment with inhibited growth of Daphnia magna: Disturbed energy metabolism and oxidative stress

High ammonia pollution is a common problem in water bodies. However, research on the mechanisms underlying the toxic effects on organisms at different nutritional levels is still insufficient. Herein, based on the environmental concentration, the toxic effects of high ammonia pollution on Daphnia magna were investigated. Overall, the feeding and filtration rates of D. magna were significantly decreased by ammonia. Growth inhibition of D. magna by ammonia was confirmed by the decreased body length. After ammonia exposure, the metabolic status of D. magna changed, the correlation network weakened, and the correlations between metabolites were disrupted. Changes occurred in metabolites primarily involved in oxidative stress, fatty acid oxidation, tricarboxylic acid cycle, and protein digestion, absorption, and synthesis, which were validated through alterations in multiple biomarkers. In addition, mitochondrial function was evaluated and was found to inhibit mitochondrial activity, which was accompanied by a decreased marker of mitochondrial activity contents and ATPase activity. Thus, the results suggested that energy metabolism and oxidative stress were involved in ammonia-induced growth toxicity. This study provides new insights into the impact of ammonia on aquatic ecological health.

Identification and functional analysis of circular RNA expression profiles associated with ammonia exposure in chicken lungs

Ammonia acts as a detrimental atmospheric pollutant, posing a sever threat to respiratory tract health and causing lung injury in humans and animals. Circular RNAs (circRNAs) are a distinctive class of non-coding RNA generated by back-splicing of linear RNA, implicated in various biological processes. However, their role in the immune response of chicken lungs to ammonia exposure remains unclear. In this study, we examined the expression profiles of circRNAs in chicken lungs under ammonia stimulation. In total, 61 differentially expressed (DE) circRNAs were identified between the ammonia exposure and control groups, including 17 up-regulated and 44 down-regulated circRNAs. The source genes of these DE circRNAs were predominantly enriched in Influenza A, SNARE interactions in vesicular transport, and Notch signaling pathway. Notably, nine DE circRNAs (circNBAS, circMTIF2, circXPO1, circSNX24, circRAB11A, circARID3B, circUSP54, circPPARA, and circERG) were selected for validation the reliability and authenticity of RNA-seq data. Results showed the back-splicing circular structure, as well as the reliability and accuracy of RNA-seq data in quantifying circRNA expression, as the RT-qPCR results were in agreement with the RNA-seq data. Moreover, we constructed the circRNA-miRNA-mRNA regulatory networks and identified several regulatory networks in chicken lungs under ammonia stimulation, including circRAB11A-gga-miR-191b-3p-BRD2 and circARID3B-gga-miR-1696-CKS2. Taken together, our study delineates the circRNA expression profile and their potential roles in the immune response of chicken lungs to ammonia exposure. These findings offer insights into molecular mechanisms that may mitigate diseases associated with ammonia induced respiratory tract pollution in humans and animals.

A Multi-Biomarker Approach in Assessing the Growth and Physiological Stress in Pangasianodon hypophthalmus under Acute Ammonia Exposure

A Multi-Biomarker Approach in Assessing the Growth and Physiological Stress in Pangasianodon hypophthalmus under Acute Ammonia Exposure

OCCUPATIONAL EXPOSURE TO AMMONIA DURING INDUSTRIAL-SCALE ANAEROBIC DIGESTION COMPOSTING OF HOUSEHOLD WASTE

Biodegradable waste material can be exploited through anaerobic digestion, an oxygen-free multi-stage process often completed by a composting step, which harnesses the power of microorganisms to break down organic matter. This waste-treatment sector is growing rapidly in France as it allows the production of valuable digestates and biogas (biomethane). One of the main occupational health concerns in this sector is exposure to ammonia. The present work focused on ammonia emitted over the course of several stages in the anaerobic digestion and composting process, and assessed employee exposure to this pollutant. Exposure was measured for distinct worker activities and work areas, as well as during the various steps of the process. The results revealed non-negligible ammonia exposure for workers operating in the dehydration (until 55 ppmV in the workplace and 17 ppmV on the worker) and composting (until 45 ppmV in the workplace and 17 ppmV on the loader driver) areas on several sites. A classical monitoring approach was supplemented by the identification of explanatory parameters contributing to exposure: material emissivity, amounts stored or handled, and ventilation systems in use. Based on these elements, recommendations were made on prevention choices, including reducing emissions at source namely by process improvement and management of stored quantities, improving existing preventive systems such as capture at source or general ventilation, and employee education to raise awareness of waste management risks and improve practices.

Rapid profiling of fish cell nitrogen metabolism with single-cell Raman spectroscopy: Unveiling enzyme's role in ammonia detoxification

Ammonia is a prevalent aquatic pollutant that disrupts cellular functions and energy metabolism in fish, posing significant environmental and health threats. This research investigates the critical role of arginase 2 (ARG2) in mitigating ammonia toxicity in fish cells and its implications in adapting to nitrogen metabolism under high ammonia exposure. Through a CRISPR-Cas9 engineered ARG2 knockdown (KD) in the Epithelioma Papulosum Cyprini (EPC) cell line, we first investigated the biochemical responses of ARG2 KD and wild-type (WT) EPC cells to ammonia stress (NH4Cl treatment), showing diminished urea production and decreased cell viability in ARG2 KD cells. Subsequently, single-cell Raman spectroscopy analysis revealed that ARG2 KD cells exhibited profound metabolic shifts, including changes in protein, nucleic acids, lipid and sugar levels, showing the adjusting role of ARG2 in the balance of carbohydrate and nitrogen metabolism. Furthermore, the upregulated responses of various amino acids, such as glutamine, arginine, alanine, glutamic acid, glycine, histidine, phenylalanine and valine, in WT cells after NH4Cl treatment diminished in ARG2 KD cells except for the decrease in aspartic acid, indicating a switching effect of ARG2 in nitrogen metabolism under ammonia stress. This study highlights ARG2's essential role in ammonia detoxification and emphasizes ARG2's protective function and its importance in metabolism, shedding light on the adaptive mechanisms fish cells deploy against high ammonia environments. These insights contribute to deep understanding of aquatic organisms' molecular responses to environmental ammonia pollution, offering potential strategies for their protection.

Effect of ammonia environment on the quality of boxed non-dairy cream

Ammonia leakage in food cold storage have adverse impact on the quality of food, which may be related to ammonia concentration and exposure time, but there is a lack of data support. In this paper, the quality of boxed non-dairy cream exposed to ammonia environment (0 (CK), 100, 500, and 1000 mL m−³) at −18 °C for 6 day were evaluated. Results showed that no ammonia residue was detected in the boxed non-dairy cream exposed for 6 days. There were no significant differences (P > 0.05) in the color value, odor, pH value, and sensory score of the non-dairy cream under the four ammonia groups during the same exposure time. And peroxide values was far below the standards limit, and benzo (α) pyrene content of all the cream groups were not detected The results indicated that all the boxed non-dairy cream in this experiment had no quality deterioration and food safety risk.

The mechanism of reactive oxygen species generation, DNA damage and apoptosis in hemocytes of Litopenaeus vannamei under ammonia nitrogen exposure

Ammonia-N poses a significant threat to aquatic animals. However, the mechanism of ROS production leading to DNA damage in hemocytes of crustaceans is still unclear. Additionally, the mechanism that cells respond to DNA damage by activating complex signaling networks has not been well studied. Therefore, we exposed shrimp to 0, 2, 10, and 20 mg/L NH4Cl for 0, 3, 6, 12, 24, 48, and 72 h, and explored the alterations in endoplasmic reticulum stress and mitochondrial fission, DNA damage, repair, autophagy and apoptosis. The findings revealed that ammonia exposure led to an increase in plasma ammonia content and neurotransmitter content (DA, 5-HT, ACh), and significant changes in gene expression of PLC and Ca2+ levels. The expression of disulfide bond formation-related genes (PDI, ERO1) and mitochondrial fission-related genes (Drp1, FIS1) were significantly increased, and the unfolded protein response was initiated. Simultaneously, ammonia-N exposure leads to an increase in ROS levels in hemocytes, resulting in DNA damage. DNA repair and autophagy were considerably influenced by ammonia-N exposure, as evidenced by changes in DNA repair and autophagy-related genes in hemocytes. Subsequently, apoptosis was induced by ammonia-N exposure, and this activation was associated with a caspase-dependent pathway and caspase-independent pathway, ultimately leading to a decrease in total hemocytes count. Overall, we hypothesized that neurotransmitters in the plasma of shrimp after ammonia-N exposure bind to receptors on hemocytes membrane, causing endoplasmic reticulum stress through the PLC-IP3R-Ca2+ signaling pathway and leading to mitochondrial fission. Consequently, this process resulted in increased ROS levels, hindered DNA repair, suppressed autophagy, and activated apoptosis. These cascading effects ultimately led to a reduction in total hemocytes count. The present study provides a molecular support for the understanding of the detrimental toxicity of ammonia-N exposure to crustaceans.

Nile tilapia (Oreochromis niloticus) show high tolerance to acute ammonia exposure but lose metabolic scope during prolonged exposure at low concentration

Ammonia is a respiratory gas that is produced during the process of protein deamination. In the unionised form (NH3), it readily crosses biological membranes and is highly toxic to fish. In the present study we examined the effects of unionized ammonia (UIA), on the resting oxygen consumption (MO2), ventilation frequency (fV), heart rate (HR) and heart rate variability (HRV) in Nile tilapia (Oreochromis niloticus). Fish were either exposed to progressively increasing UIA concentrations, up to 97 µM over a 5 h period, or to a constant UIA level of 7 µM over a 24 h period. For both treatment groups resting MO2, HR and fV were recorded as physiological variables. Relative to the control group, the fish groups exposed to the incremental UIA levels did not exhibit significant changes in their MO2, HR and fV at UIA concentrations of 4, 10, 35, or 61 µM compared to control fish. Exposure to 97 µM UIA, however, elicited abrupt and significant downregulations (p < 0.05) in all three responses, as MO2, HR and fv decreased by 25, 54 and 76 % respectively, compared to control measurements. Heart rate became increasingly irregular with increasing UIA concentrations, and heart rate variability was significantly increased at 61 and 97 µM UIA. Prolonged exposure elicited significant changes at exposure 7 µM UIA. Standard (SMR) and maximum metabolic rate (MMR) were significantly reduced, as was the corresponding fV and HR. It is evident from this study that Nile tilapia is tolerant to short term exposure to UIA up to 61 µM but experience a significant metabolic change under conditions of prolonged UIA exposures even at low concentrations.

MiR-199-5p mediates the regulation of autophagy by targeting mTOR signaling and involvement in ammonia detoxification under ammonia stress in yellow catfish (Pelteobagrus fulvidraco)

Ammonia is a widely distributed hazardous aquatic pollutant that poses a threat to the development of aquatic organisms. A two-stage study was carried out to the response of yellow catfish to ammonia stress.At stage 1, yellow catfish were subjected to 0 mg/L total ammonia nitrogen (T-AN, CON group) and 125 mg/L T-AN (AM group) for 96 h, respectively. At stage 2, yellow catfish in AM group were transferred to water containing 0 mg/L T-AN for a 48-h recovery experiment (AMR group). Ammonia exposure significantly increases serum ammonia (SA), total cholesterol (T-CHO), triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels, while decreases glucose (Glu) level. Only SA, GLU, TCHO, and AST returned to normal levels in AMR group, while extensive hepatocyte necrosis and vacuolization persisted. The results showed that the liver possesses a certain degree of ammonia-lowering capacity, yet ammonia-induced liver damage is irreversible. Ammonia stress-induced 486 down-regulated and 18 up-regulated microRNAs (miRNAs). Functional enrichment analysis of the top 10 miRNAs highlighted significant effects of ammonia on the “mTOR signaling pathway” and “autophagy-animals”. Furthermore, the significant negative correlation between the expression levels of miR-199-5p and mTOR suggests that mTOR as a potential target gene of miR-199-5p. The levels of LC3B, autophagosomes (AP), and autolysosomes (AL) in the AM group decreased significantly after 24 h of ammonia stress but returned to baseline after 96 h. Additionally, increased numbers of AP and AL were observed in the AMR group, suggesting that hepatic autophagy is initially suppressed under ammonia stress, followed by spontaneous recovery. This study also found that the expression levels of urea and glutamine synthesis-related genes (cps 1; arg; otc; ass; asl, and gs) significantly increased in the AM and AMR groups. Additionally, the contents of urea and glutamine in the liver was significantly elevated in the AM group. This indicates a simultaneous occurrence of urea and glutamine synthesis with the activation of autophagy during ammonia detoxification. The miR-199-5p/mTOR axis may regulate liver autophagy, potentially contributing to ammonia detoxification. The study has provided novel targets for enhancing ammonia tolerance in fish through nutritional regulation.

Development of Intelligent Indicators Based on Cellulose and Prunus domestica Extracted Anthocyanins for Monitoring the Freshness of Packaged Chicken.

Meat is a widely consumed food globally; however, variations in storage conditions along its supply chain can pose a potential food safety risk for consumers. Addressing this concern, we have developed freshness indicators designed to monitor the condition of packaged chicken. In this study, anthocyanins were infused with cellulose paper measuring 2 × 2 cm, and subsequent analysis focused on examining color changes concerning deteriorating chicken stored at 30°C for 48 h, with varying sample sizes being considered. The rise in total volatile nitrogen (TVB-N) compounds from an initial value of 3.64 ± 0.39 mg/100 g to 28.17 ± 1.46 mg/100 g acted as the stimulus for the color change in the indicator, simultaneously influencing the pH from the initial 7.03 ± 0.16 to 8.12 ± 0.39. The microbial load (aerobic plate count) of the chicken samples was also significantly increased. This collective shift in various parameters strongly suggests the occurrence of spoilage in chicken meat. The pH indicators exhibited a dark pink to red color for fresh chicken. As the chicken meat turned towards spoilage, the indicators changed to a dark blue and then a pale green color. FTIR spectroscopy results confirmed the presence of cellulose and anthocyanins. The FTIR analysis also validated the immobilization of plum anthocyanins within the cellulose paper and assessed their stability after 8 months of storage. Notably, the indicators demonstrated rapid sensitivity, showing a 20.5% response within one minute of ammonia exposure, which further increased to 29.5% after 3 min of exposure. The total color difference (ΔE) steadily rose in all the examined samples and also under various storage conditions. Overall, the indicators developed in this study exhibited a highly pronounced color transition, capable of distinguishing between fresh and spoiled chicken samples depending on the extent of spoilage and the specific day of observation.

Regulating Effect of Exogenous α-Ketoglutarate on Ammonium Assimilation in Poplar.

Extensive industrial activities and anthropogenic agricultural practices have led to substantial ammonia release to the environment. Although croplands can act as ammonia sinks, reduced crop production under high concentrations of ammonium has been documented. Alpha-ketoglutarate (AKG) is a critical carbon source, displaying pleiotropic physiological functions. The objective of the present study is to disclose the potential of AKG to enhance ammonium assimilation in poplars. It showed that AKG application substantially boosted the height, biomass, and photosynthesis activity of poplars exposed to excessive ammonium. AKG also enhanced the activities of key enzymes involved in nitrogen assimilation: glutamine synthetase (GS) and glutamate synthase (GOGAT), elevating the content of amino acids, sucrose, and the tricarboxylic acid cycle (TCA) metabolites. Furthermore, AKG positively modulated key genes tied to glucose metabolism and ATP synthesis, while suppressing ATP-depleting genes. Correspondingly, both H+-ATPase activity and ATP content increased. These findings demonstrate that exogenously applying AKG improves poplar growth under a high level of ammonium treatment. AKG might function through sufficient carbon investment, which enhances the carbon-nitrogen balance and energy stability in poplars, promoting ammonium assimilation at high doses of ammonium. Our study provides novel insight into AKG's role in improving poplar growth in response to excess ammonia exposure.