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1.
Carbon-dependent alleviation of ammonia toxicity for algae cultivation and associated mechanisms exploration.
Lu, Q, Chen, P, Addy, M, Zhang, R, Deng, X, Ma, Y, Cheng, Y, Hussain, F, Chen, C, Liu, Y, et al
Bioresource technology. 2018;:99-107
Abstract
Ammonia toxicity in wastewater is one of the factors that limit the application of algae technology in wastewater treatment. This work explored the correlation between carbon sources and ammonia assimilation and applied a glucose-assisted nitrogen starvation method to alleviate ammonia toxicity. In this study, ammonia toxicity to Chlorella sp. was observed when NH3-N concentration reached 28.03mM in artificial wastewater. Addition of alpha-ketoglutarate in wastewater promoted ammonia assimilation, but low utilization efficiency and high cost of alpha-ketoglutarate limits its application in wastewater treatment. Comparison of three common carbon sources, glucose, citric acid, and sodium bicarbonate, indicates that in terms of ammonia assimilation, glucose is the best carbon source. Experimental results suggest that organic carbon with good ability of generating energy and hydride donor may be critical to ammonia assimilation. Nitrogen starvation treatment assisted by glucose increased ammonia removal efficiencies and algal viabilities.
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2.
Glutamate production from ammonia via glutamate dehydrogenase 2 activity supports cancer cell proliferation under glutamine depletion.
Takeuchi, Y, Nakayama, Y, Fukusaki, E, Irino, Y
Biochemical and biophysical research communications. 2018;(1):761-767
Abstract
Cancer cells rapidly consume glutamine as a carbon and nitrogen source to support proliferation, but the cell number continues to increase exponentially after glutamine is nearly depleted from the medium. In contrast, cell proliferation rates are strongly depressed when cells are cultured in glutamine-free medium. How cancer cells survive in response to nutrient limitation and cellular stress remains poorly understood. In addition, rapid glutamine catabolism yields ammonia, which is a potentially toxic metabolite that is secreted into the extracellular space. Here, we show that ammonia can be utilized for glutamate production, leading to cell proliferation under glutamine-depleted conditions. This proliferation requires glutamate dehydrogenase 2, which synthesizes glutamate from ammonia and α-ketoglutarate and is expressed in MCF7 and T47D cells. Our findings provide insight into how cancer cells survive under glutamine deprivation conditions and thus contribute to elucidating the mechanisms of tumor growth.
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3.
Two-stage partial nitritation-anammox process for high-rate mainstream deammonification.
Liu, W, Yang, D, Shen, Y, Wang, J
Applied microbiology and biotechnology. 2018;(18):8079-8091
Abstract
Increasing information supported that achieving high-rate mainstream deammonification through two-stage partial nitritation (PN)-anammox process should be a better option than through single-stage process. However, direct experimental evidence was limited so far. Herein, a two-stage PN-anammox process was successfully operated for nitrogen removal from low-strength wastewater in winter. Influent shift from synthetic wastewater to actual anaerobically pretreated sewage had little impact on the process performance. Promising nitrogen removal rates (NRRs) of 0.28-0.07 kg N m-3 d-1 with an average effluent concentration of 5.2 mg TN L-1 were achieved for the anaerobically pretreated sewage treatment at 15-7 °C. Moreover, nearly all the degradable COD in the pretreated sewage was steadily removed in the first-stage PN reactor, despite the varied influent COD concentrations of 22-78 mg L-1 and the operating temperature decrease, suggesting the positive role of the first-stage PN in protecting anammox bacteria. The low temperature seemingly was the only deterministic factor inhibiting the anammox activity, and hence made the anammox reaction to be the rate-limiting step for nitrogen removal in the two-stage PN-anammox process. Unexpectedly, nearly all the anammox bacteria remained active at low temperatures with the process actual anammox activity reached about 76-85% of their maximum potential, implying that higher NRRs would be easily realized through bioaugmentation or enrichment of anammox bacteria. Overall, the present investigation provides direct and valuable information for implementing the two-stage PN-anammox process to treat mainstream municipal wastewater. A control strategy was also proposed to optimize the operation of the two-stage mainstream deammonification process.
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4.
The potential role of malonic acid in the atmospheric sulfuric acid - Ammonia clusters formation.
Zhang, H, Li, H, Liu, L, Zhang, Y, Zhang, X, Li, Z
Chemosphere. 2018;:26-33
Abstract
Malonic acid (MOA), one of the major dicarboxylic acids (DCAs) in aerosols, has been identified experimentally and computationally to be a strong acid. However, its potential role in the atmospheric clusters formation is still ambiguous. Hence, the participant mechanism of MOA on the formation of atmospheric sulfuric acid (SA)- ammonia (A) clusters was investigated by combining computational methods with atmospheric cluster dynamics code (ACDC). The most stable molecular structures obtained at the M06-2X/6-311++G(3df,3pd) level of theory shows that the added MOA molecule in the SA-A-based clusters presents a promotion on the interactions between SA and A molecules. ACDC simulations indicate directly an obvious enhancement strength RMOA on the clusters formation rates at 218 K and the concentration of MOA ([MOA]) larger than 108 molecules cm-3, up to five orders of magnitude. Meanwhile, enhancement strength of MOA is compared with that of glycolic acid, and as expected, MOA presents a superior enhancement strength. Both RMOA and the compared enhancement strength (rcom) present a positive dependency on [MOA] and a negative dependency on [SA]. With the increase of [A], both RMOA and rcom (except at [SA] = 104 molecules cm-3) first increase, reaching the maximum value and then decrease. Finally, a catalytic participant mechanism of MOA where MOA acts as a mediate bridge for the formation of pure SA-A-based clusters has been identified by tracing the main growth pathways of the system.
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5.
The relationship between serum ammonia level and neurologic complications in patients with acute glufosinate ammonium poisoning: A prospective observational study.
Cha, YS, Kim, H, Lee, Y, Choi, EH, Kim, HI, Kim, OH, Cha, KC, Lee, KH, Hwang, SO
Human & experimental toxicology. 2018;(6):571-579
Abstract
Glufosinate ammonium poisoning can cause neurological complications even after a symptom-free period. We prospectively investigated the predictors of neurologic complications in acute glufosinate ammonium poisoning and the change of serum ammonia level as a predictor of patient's presence and recovery of neurologic complication. This prospective observational study collected data from consecutive patients diagnosed with acute glufosinate ammonium poisoning between September 2014 and June 2016. Serum ammonia was serially measured. The patients were divided into two groups: the neurologic complication group and the nonneurologic complication group. We also defined 25 other insecticide- or herbicide-poisoned patients as controls. The neurologic complication group included 18 patients (72.0%). The latency period for neurologic complications was within 48-h postingestion. The peak ammonia level was statistically higher in the neurologic complication group than in the control group ( p < 0.001) and the nonneurologic complication groups ( p = 0.001). There was a statistical difference between the nonneurologic complication group and the neurologic complication group ( p = 0.0085) in terms of ingested amount. The peak ammonia was the only predictor for the development of neurologic complications (the optimal cutoff: 90 μg/dL). In patients with mental changes, the mean serum ammonia levels before and after recovery of the mental changes were statistically different ( p = 0.0019). In acute glufosinate ammonium poisoning, serial serum ammonia level measurements are needed and a serum peak ammonia level greater than 90 μg/dL is a predictor of neurologic complications. Also, it is important to treat the hyperammonemia in acute glufosinate ammonium poisoning.
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6.
The Eponymous Cofactors in Cytochrome P460s from Ammonia-Oxidizing Bacteria Are Iron Porphyrinoids Whose Macrocycles Are Dibasic.
Smith, MA, Lancaster, KM
Biochemistry. 2018;(3):334-343
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Abstract
The enzymes hydroxylamine oxidoreductase and cytochrome (cyt) P460 contain related unconventional "heme P460" cofactors. These cofactors are unusual in their inclusion of nonstandard cross-links between amino acid side chains and the heme macrocycle. Mutagenesis studies performed on the Nitrosomonas europaea cyt P460 that remove its lysine-heme cross-link show that the cross-link is key to defining the spectroscopic properties and kinetic competence of the enzyme. However, exactly how this cross-link confers these features remains unclear. Here we report the 1.45 Å crystal structure of cyt P460 from Nitrosomonas sp. AL212 and conclude that the cross-link does not lead to a change in hybridization of the heme carbon participating in the cross-link but rather enforces structural distortions to the macrocycle away from planarity. Time-dependent density functional theory coupled to experimental structural and spectroscopic analysis suggest that this geometric distortion is sufficient to define the spectroscopic properties of the heme P460 cofactor and provide clues toward establishing a relationship between heme P460 electronic structure and function.
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7.
Blood Ammonia as a Possible Etiological Agent for Alzheimer's Disease.
Jin, YY, Singh, P, Chung, HJ, Hong, ST
Nutrients. 2018;(5)
Abstract
Alzheimer’s disease (AD), characterized by cognitive decline and devastating neurodegeneration, is the most common age-related dementia. Since AD is a typical example of a complex disease that is affected by various genetic and environmental factors, various factors could be involved in preventing and/or treating AD. Extracellular accumulation of beta-amyloid peptide (Aβ) and intracellular accumulation of tau undeniably play essential roles in the etiology of AD. However, interestingly enough, medications targeting Aβ or tau all failed and the only clinically efficient medications for AD are drugs targeting the cholinergic pathway. Also, a very intriguing discovery in AD is that the Mediterranean diet (MeDi), containing an unusually large quantity of Lactobacilli, is very effective in preventing AD. Based on recently emerging findings, it is our opinion that the reduction of blood ammonia levels by Lactobacilli in MeDi is the therapeutic agent of MeDi for AD. The recent evidence of Lactobacilli lowering blood ammonia level not only provides a link between AD and MeDi but also provides a foundation of pharmabiotics for hyperammonemia as well as various neurological diseases.
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Ammonia Inhalation Does Not Increase Deadlift 1-Repetition Maximum in College-Aged Male and Female Weight Lifters.
Vigil, JN, Sabatini, PL, Hill, LC, Swain, DP, Branch, JD
Journal of strength and conditioning research. 2018;(12):3383-3388
Abstract
Vigil, JN, Sabatini, PL, Hill, LC, Swain, DP, and Branch, JD. Ammonia inhalation does not increase deadlift 1-repetition maximum in college-aged male and female weight lifters. J Strength Cond Res 32(12): 3392-3397, 2018-Ammonia inhalant use by powerlifters and weight lifters is a prevalent practice with little research support for improved performance. The purpose of this study was to investigate the effects of ammonia as a stimulant on athletic performance during a deadlift 1-repetition maximum (1RM) absolute strength test. Subjects (men: n = 10, mean ± SD age = 21 ± 1 year, mass = 72.5 ± 6.8 kg; and women: n = 10, age = 22 ± 5 years, mass = 66.2 ± 8.1 kg) were required to have at least 2 years of resistance training experience while lacking a history of asthma, lightheadedness, fainting, anaphylaxis, sickle cell traits, and other respiratory disorders. After a baseline 1RM test, subjects were paired by 1RM performance and gender, then randomly assigned in a counterbalanced treatment order to control (water) or ammonia trials after a minimum 72-hour recovery period for another 1RM test involving attempts at 100.0, 102.5, 105.0, and 107.5% of the established 1RM value. Testing was then repeated after the minimum rest period for the remaining trial. Results revealed the expected gender main effect for absolute deadlift 1RM (93.0 ± 29.5 [women]; 152.0 ± 29.5 kg [men]; p < 0.001), but no trial main effect (p = 0.874) or gender by trial interaction effect (baseline = 93.0 ± 15.3, 151.8 ± 42.3 kg; water = 92.0 ± 12.5, 150.9 ± 37.8 kg; ammonia = 92.5 ± 16.4, 153.4 ± 37.9 kg) for women and men, respectively (p = 0.559). Within the limitations of this study, there is no support for the practice of ammonia inhalation to improve deadlift 1RM in training or competition.
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The impact of ammonia levels and dialysis on outcome in 202 patients with neonatal onset urea cycle disorders.
Hediger, N, Landolt, MA, Diez-Fernandez, C, Huemer, M, Häberle, J
Journal of inherited metabolic disease. 2018;(4):689-698
Abstract
Neonatal onset hyperammonemia in patients with urea cycle disorders (UCDs) is still associated with high morbidity and mortality. Current protocols consistently recommend emergency medical and dietary management. In case of increasing or persistent hyperammonemia, with continuous or progressive neurological signs, dialysis is performed, mostly as ultima ratio. It is presently unknown whether the currently defined ammonia threshold (e.g., at 500 μmol/L) to start dialysis is useful to improve clinical outcome. A systematic review of clinical and biochemical data from published neonatal onset UCD patients was performed to identify factors determining clinical outcome and to investigate in which clinical and biochemical setting dialysis was most effective. A total of 202 patients (118 proximal and 84 distal UCDs) described in 90 case reports or case series were included according to predefined inclusion/exclusion criteria. Median age at onset was three days and mean ammonia that triggered start of dialysis was 1199 μmol/L. Seventy-one percent of all patients received any form of dialysis. Total mortality was 25% and only 20% of all patients had a "normal" outcome. In general, patients with higher ammonia levels were more likely to receive dialysis, but this had for most patients no influence on outcome. In conclusion, in severe neonatal onset hyperammonemia, the current practice of dialysis, which effectively clears ammonia, had no impact on outcome. It may be essential for improving outcome to initiate all available treatment options, including dialysis, as early as possible.
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10.
Submucosal hematoma: a new distinctive sign during emergency upper digestive endoscopy for ammonia ingestion.
Gelu-Simeon, M, Chuong, AP, Saliba, F, Thiery, G, Laurent, M, Vilain, C, Borel, M, Amaral, L, Alexis, M, Saint-Georges, G, et al
BMC gastroenterology. 2018;(1):92
Abstract
BACKGROUND Submucosal hematoma has never been associated with caustic injuries. Long-term follow-up of patients who ingested ammonia is not well known and ammonia ingestion is rare. METHODS In a Single-center observational study, prospective data were collected from 2009 to 2013, in patients over the age of 14 years old referred for ammonia ingestion. The emergency and follow-up endoscopic data and the outcome were reported. RESULTS Ammonia ingestion occurred in 43 patients. Submucosal hematoma of the gastric wall was a distinctive endoscopic sign observed in 15 (34.8%) cases. Oropharyngeal lesions were present in 30 (69.8%) patients, which was associated with ingestion with suicidal intent in 18 cases. Mild and severe endoscopic lesions (grade IIB to IIIB) were found in 16 (37.2%) cases with 10 (23.3%) cases presenting submucosal hematoma at initial endoscopy. A complete spontaneous gastric healing was frequently observed in 36 (83.7%) cases. In 11 cases with submucosal hematoma, a favourable outcome was observed with a medical treatment, however 6 of these patients had severe endoscopic lesions initially. CONCLUSIONS Submucosal hematoma of the gastric wall is an endoscopic sign occurring frequently in ammonia ingestion. Submucosal hematoma should be distinguished from necrosis in order to avoid false misclassification in favour of more severe lesions, which would lead to an abusive surgery.