Ammonia Levels Research Articles

Regulatory mechanisms of biochar alleviating ammonia inhibition to methanogenesis during long-term operation of anaerobic membrane bioreactor treating swine wastewater

Anaerobic Membrane Bioreactor (AnMBR) is regarded as an advanced technology for the anaerobic digestion (AD) of swine wastewater. However, the high ammonia level in swine wastewater is a crucial issue to inhibit methane production. This study aimed to establish a biochar-assisted AnMBR (BC) to mitigate ammonia inhibition during AD of swine wastewater. As the gradual ammonia loading rate (ALR) increased from 3.0 g/L to 6.0 g/L, BC maintained methane yields ranging from 74.9 % to 48.1 %, which were 9.1 % to 33.3 % higher than those of a regular AnMBR (CT). Moreover, the COD removal efficiency steadily surpassed 80 %. Although the increase in ALR had negative effects on both BC and CT, the presence of biochar enhanced the methanogenic activity of bulk sludge, specifically accelerating processes involved in syntrophic acetate oxidation and CO2-reducing methanogenesis under high ALR conditions. Integrated characterizations using PARAFAC-based EPS analysis, INT-ETS, and WO3 probe-based extracellular electron transfer (EET) activities indicated that biochar stimulated the secretion of humic-like and aromatic protein-like compounds in the TB-EPS, which likely established a redox-active matrix with biochar between VFA oxidation bacteria and CO2-reducing methanogens to facilitate EET. This potentially made the syntrophic VFA oxidation with favorably thermodynamic kinetics under high ammonia stress. Furthermore, the analysis of microbial community coupling prediction of functional genes associated with methanogenic pathways revealed that as ALR increased, the presence of biochar re-shaped the microbial communities by enriching electro-active Syntrophomonas and Methanosarcina/Methanospirillum, which mainly triggering EET-based syntrophic methanogenesis by accelerating the intracellular enzymatic transformation from Formylmethanofuran to 5,10-Methylenetetrahydromethanopterin process. We expect the major findings of this study provide new insights to understand the mechanisms of biochar alleviating ammonia inhibition during long-term operation of AnMBR.

Real-time ammonia estimation in recirculating aquaculture systems: A data assimilation approach

Recirculating aquaculture systems offer sustainable fish production but face challenges related to ammonia levels. Ammonia, particularly the un-ionized fraction, NH3, can negatively impact fish growth and health. Traditional ammonia estimation methods, including offline analyses and affordable, yet inaccurate, in-situ measurements, lack the ability to provide reliable real-time insights. Data assimilation combines simulation models and in-situ measurements to provide more accurate estimations. In this study, we demonstrate a novel approach using data assimilation to enhance real-time ammonia estimation in RAS. First, ammonia dynamics are described by forming equations that constitute a simulation model, based on the feeding amounts and the biofilter removal rate parameters. Then, an extended Kalman filter is presented and customized to integrate the simulation model and total ammonia nitrogen measurements for estimating NH3, NH4+, and biofilter parameters. We validated our method through synthetic and laboratory case studies and demonstrated its superior estimation capability as compared to in situ measurements or simulation models. Furthermore, improved ammonia estimation led to improved current and future fish weight estimations, which can be essential for reliable RAS management. The proposed approach facilitates wider adoption of DA in challenging estimations in aquaculture.

A Rare Case of Neuronal Ceroid Lipofuscinosis-Type 1 (NCL-1) with Vitamin D-Dependent Rickets-Type 1 (VDDR-1), Complex 1 Mitochondrial Deficiency, and Mixed Variant-Checkerboard and Phylloid Type of Pigmentary Mosaicism.

Introduction Neuronal ceroid lipofuscinosis-type 1 (NCL-1) is a neurodegenerative lysosomal storage disorder. Vitamin D-dependent rickets type 1 (VDDR-1) is a rare cause of refractory rickets. Here, we report an unusual association of NCL-1 with VDDR-1. Case A 3-year-old boy presented with a history of seizures from 45 days of life, delayed development, and loss of attained milestones at 20 months of age, along with progressive vision impairment since 1 year. Examination showed a failure to thrive, microcephaly, rachitic rosary, checkerboard and phylloid type of pigmentary mosaicism, fundus showed disc pallor with generalized narrowing of arterioles, bilateral retinitis pigmentosa, spasticity and dystonia, brisk reflexes, extensor plantar, and left choreoathetoid movements. Investigations showed hypocalcemia (7.8 mg/dL), normal phosphorus (3.9 mg/dL), elevated alkaline phosphatase (508.8 U/L), elevated parathyroid hormone (513.35 pg/mL), low 1,25-dihydroxy-vitamin D (9.93 pg/mL), and normal renal function. The child had metabolic acidosis, elevated ammonia (403.9 micromol/L), lactate (95 mg/dL, normal range 4.5-19.8 mg/dL), and creatine phosphokinase (432 U/L) level, and normal tandem mass spectroscopy. X-ray wrist showed healing vitamin deficiency rickets. Abnormal electroencephalogram was suggestive of low voltage activity. Magnetic resonance imaging brain showed gross cerebral and cerebellar atrophy. A muscle biopsy showed scattered atrophic fibers and several ultrastructural granular osmiophilic deposits and some mitochondrial aggregates of varying size were observed. Mitochondrial respiratory chain enzyme assay exhibited complex-1 deficiency (activity < 30%). Genetic analysis showed two pathogenic mutations: homozygous nonsynonymous variation c.674T > C in exon 7 of the PPT1 gene and a homozygous frameshift variation c.1178_1179delAA in exon 7 of CYP27B1 confirming the diagnosis of NCL-1 with VDDR-1. The child was treated with a low protein diet, levetiracetam, clonazepam, trihexyphenidyl, haloperidol, calcium supplement, calcitriol, and sodium benzoate; some improvement in clinical and biochemical parameters was noted on follow-up. Conclusion This is a novel association of NCL-1 with VDDR-1 associated with complex-1 mitochondrial deficiency which has previously not been reported in the literature.

Teasing out the Effects of Natural Stressors at Chemically Contaminated Sites.

Aquatic ecosystems are often impacted by a multitude of stressors, many of which are introduced by a combination of anthropogenic activities such as agricultural development, urbanization, damming, and industrial discharge. Determining the primary stressors responsible for ecological impairments at a site can be complex and challenging; however, it is crucial for making informed management decisions. Improper diagnosis of an impaired system can lead to misguided attempts at remediation, which can be both time consuming and costly. We focused on the development, implementation, and evaluation of methodologies that, in combination, allowed us to identify the primary stressors. These included a four-phase, weight-of-evidence (WOE) assessment including in situ Toxicity Identification and Evaluation (iTIE) testing, physicochemical and macrobenthos characterization, reciprocal sediment transplants, and laboratory and in situ toxicity testing. The contaminants of concern (COCs) at the site were elevated levels of ammonia, chloride, pH, and total dissolved solids in groundwater upwellings into a high-quality waterway. Reciprocal transplants of site sediments and nearby reference sediments and traditional benthic sampling showed impaired benthic indices and multiple stations around a contaminated industrial settling basin. Impaired stations had elevated COCs in groundwaters but exhibited a steep vertical concentration gradient, with concentrations decreasing near the sediment-surface water interface. We describe Phase 4 of the study, which focused on teasing out the role of dissolved oxygen sags in benthic macroinvertebrate responses. Extensive submerged and emergent macrophytes, algae, and cyanobacteria co-occurred at the impaired sites and increased throughout the summer. Laboratory testing suggested that ammonia and pH were possibly toxic at the sites, based on groundwater concentrations. The in situ toxicity testing, however, showed toxicity occurring even at stations with low levels of COCs concurrently with large diurnal fluxes in dissolved oxygen (DO). A final phase using a type of iTIE approach utilized limnocorrals with and without aeration and with in situ toxicity measures using Hyalella azteca. The Phase 4 assessment revealed that low DO levels were primarily responsible for impaired benthic communities, and COC upwellings were diluted at the sediment-water interface to nontoxic levels. These findings will allow for improved management decisions for more efficient and effective restoration activities. Environ Toxicol Chem 2024;43:1524-1536. © 2024 SETAC.

Imaging features, classification and clinical features of intrahepatic congenital portosystemic shunts.

Congenital portosystemic shunts (CPSS) are a rare developmental anomaly diverting blood flow from the portal venous system and the liver to the systemic venous system. This case series examines the sonographic imaging findings, shunt classification, ultrasound shunt ratios, and outcomes in nine children (5 females, 4 males) admitted to our institution between 2015 and 2022 were included in this study. The shunts were initially categorized by the Parks classification and were followed by serial ultrasounds. Clinical presentation, clinical course, laboratory data, shunt ratios, and time to shunt closure were all followed on subsequent ultrasounds. The most common type of CPPS was the Type 3 shunt. In cases where shunt ratios were measured, the shunt ratio gradually decreased in tandem with decreasing ammonia levels until spontaneous closure was achieved. Predictors of lack of shunt closure included high shunt ratios and Type 4 shunts. Patients with CPPS can be followed with the shunt ratio calculation obtained from sonographic imaging, which may correlate to ammonia levels and indicate risk of hepatic encephalopathy as well as predict speed and timing of closure.

Predicting the Occurrence of Substituted and Unsubstituted, Polycyclic Aromatic Compounds in Coking Wastewater Treatment Plant Effluent using Machine Learning Regression

Organic contaminants such as polycyclic aromatic compounds (PACs) occurring in industrial effluents can not only persist in wastewater but transform into more toxic and mobile, substituted heterocyclic products during treatment. Thus, predicting the occurrence of PACs and their heterocyclic derivatives (HPACs) in coking wastewater is of utmost importance to reduce the environmental risks in water bodies that receive industrial effluents. Although HPACs can be monitored through sampling and analysis, the characterisation techniques used in their analyses are costly and time-consuming. In this study, we propose 3 distinct kernel-based machine learning (ML) models for predicting PACs including substituted HPACs and alkylated PACs occurring in coking wastewater. By using routinely measured wastewater quality data as input for our models, we predicted the occurrence of 14 HPACs in the final effluent of a coking wastewater treatment plant. Support Vector Machine based regression model (SVR) used for HPAC prediction showed the highest R2 of 0.83. Performance assessment of SVR model showed a mean absolute logarithmic error (MALE) of 0.46 and root mean square error (RMSE) of 0.073 ng/L. Comparatively, K-Nearest Neighbor and Random Forest models showed lower R2 of 0.75 and 0.76 respectively for HPAC prediction. Feature analysis attributed the superior predictability of SVR model likely to its higher weightage (81%) towards dissolved organic carbon and total ammonia as input variables. Both these variables could capture the underlying secondary PAC transformations likely occurring in the treatment plant. Partial dependence plots predicted that ammonia levels higher than 120 mg/L and DOC levels of 50–60 mg/L were likely linked to higher HPACs occurring in the final effluent. This work highlights the capability of kernel-based ML models in capturing nonlinear wastewater chemistry and offers a tool for monitoring trace organic contaminants released in coking effluents.

NHH promotes Sepsis-associated Encephalopathy with the expression of AQP4 in astrocytes through the gut-brain Axis.

Sepsis-associated encephalopathy (SAE) is a significant cause of mortality in patients with sepsis. Despite extensive research, its exact cause remains unclear. Our previous research indicated a relationship between non-hepatic hyperammonemia (NHH) and SAE. This study aimed to investigate the relationship between NHH and SAE and the potential mechanisms causing cognitive impairment. In the in vivo experimental results, there were no significant abnormalities in the livers of mice with moderate cecal ligation and perforation (CLP); however, ammonia levels were elevated in the hippocampal tissue and serum. The ELISA study suggest that fecal microbiota transplantation in CLP mice can reduce ammonia levels.Reduction in ammonia levels improved cognitive dysfunction and neurological impairment in CLP mice through behavioral, neuroimaging, and molecular biology studies. Further studies have shown that ammonia enters the brain to regulate the expression of aquaporins-4 (AQP4) in astrocytes, which may be the mechanism underlying brain dysfunction in CLP mice. The results of the in vitro experiments showed that ammonia up-regulated AQP4 expression in astrocytes, resulting in astrocyte damage. The results of this study suggest that ammonia up-regulates astrocyte AQP4 expression through the gut-brain axis, which may be a potential mechanism for the occurrence of SAE.

Insights into Effects of Combined Capric and Lauric Acid on Rumen Bacterial Composition.

This study used next-generation sequencing to assess the impact of combined capric acid (C10) and lauric acid (C12) on the ruminal bacterial composition. Eight Holstein cows were randomly assigned to two groups using a cross-over design. The cows were fed two silage-based diets with the addition of either 100 g of stearic acid per cow per day (control), or 50 g of capric acid and 50 g of lauric acid per cow per day (C10 + C12). On day 18, 250 mL of rumen fluid was collected from each cow, and DNA was isolated, amplified, and sequenced. Treatment did not alter bacterial diversity indices, the relative abundance of archaea, nor the fiber-degrading microorganisms, except for a decrease in Fibrobacter (from 2.9% to 0.7%; p = 0.04). The relative abundance of Prevotellaceae decreased (from 39.9% to 29.6%; p = 0.009), which is notable because some members help to efficiently utilize ammonia by releasing it slowly into the rumen. Furthermore, the relative abundance of Clostridia increased (from 28.4% to 41.5%; p = 0.008), which may have aided the increased ammonia-nitrogen levels in the rumen, as this class contains hyperammonia-producing members. Our study reveals alterations in bacterial abundances with implications for rumen ammonia levels, offering insights into potential strategies for modulating rumen fermentation processes and methane production in ruminant livestock.

Intravenous versus oral ‘l-ornithine-l-aspartate’ in overt hepatic encephalopathy: a randomized comparative study

Hepatic encephalopathy (HE), a morbid ordeal affecting chronic liver disease patients always insists for the search of a rational, superior & infallible agent beyond the time-proven standards i.e., Lactulose & Rifaximin. In this RCT, we compared the efficacy of intravenous (IV) l-ornithine-l-aspartate(LOLA) versus Oral LOLA in patients with chronic liver disease(CLD) enduring overt Hepatic Encephalopathy(OHE). 40 CLD patients with OHE were randomly assigned IV or oral LOLA in a 1:1 ratio. Patients were graded for HE and monitored for serum ammonia levels from day 1 to day 5. The aim was to compare IV versus oral LOLA efficacy in HE grades improvement and its correlation with ammonia levels. The study was registered with clinical trials registry-India, CTRI/2020/12/029943. Baseline characteristics of patients in both groups were similar. The mean difference in ammonia levels from day 1 to day 5 was 55.4 ± 32.58 µmol/L in the IV LOLA group and 60.75 ± 13.82 µmol/L in the oral LOLA group (p = 0.511). Significant reductions in ammonia levels were observed from day 1 to day 5 within each group (p < 0.001). HE grade & ammonia correlated positively in both groups. LOLA, regardless of administration route, has demonstrated efficacy in OHE.

Genome-Wide Identification, Molecular Characterization, and Expression Analysis of the HSP70 and HSP90 Gene Families in Thamnaconus septentrionalis.

Heat shock proteins (HSPs) are a class of highly conserved proteins that play an important role in biological responses to various environmental stresses. The mariculture of Thamnaconus septentrionalis, a burgeoning aquaculture species in China, frequently encounters stressors such as extreme temperatures, salinity variations, and elevated ammonia levels. However, systematic identification and analysis of the HSP70 and HSP90 gene families in T. septentrionalis remain unexplored. This study conducted the first genome-wide identification of 12 HSP70 and 4 HSP90 genes in T. septentrionalis, followed by a comprehensive analysis including phylogenetics, gene structure, conserved domains, chromosomal localization, and expression profiling. Expression analysis from RNA-seq data across various tissues and developmental stages revealed predominant expression in muscle, spleen, and liver, with the highest expression found during the tailbud stage, followed by the gastrula, neurula, and juvenile stages. Under abiotic stress, most HSP70 and HSP90 genes were upregulated in response to high temperature, high salinity, and low salinity, notably hspa5 during thermal stress, hspa14 in high salinity, and hsp90ab1 under low salinity conditions. Ammonia stress led to a predominance of downregulated HSP genes in the liver, particularly hspa2, while upregulation was observed in the gills, especially for hsp90b1. Quantitative real-time PCR analysis corroborated the expression levels under environmental stresses, validating their involvement in stress responses. This investigation provides insights into the molecular mechanisms of HSP70 and HSP90 in T. septentrionalis under stress, offering valuable information for future functional studies of HSPs in teleost evolution, optimizing aquaculture techniques, and developing stress-resistant strains.

Examining the impact of agricultural drainage ditch management on in-stream bacterial communities involved in nitrogen cycling: insights from the Environmental Change One Health Observatory (ECO2)

IntroductionAgricultural drainage ditches are essential for maintaining flow efficiency and are often managed by brushing (i.e., vegetation clearing along ditch banks) and dredging. These maintenance practices not only impact flow but also the ditches’ capacity to process and assimilate agricultural chemicals. However, the influence of ditch management on microbial activities, essential in processing and transforming these contaminants, remains underexplored.MethodsWe conducted a four-year surface water sampling campaign in two long-established (over 40 years) agricultural drainage ditches situated in eastern Ontario, Canada. One drainage ditch underwent intensive bank brushing and channel dredging, while the other remained unmanaged. We assessed the impact of these contrasting ditch management practices on the diversity and compositional structure of surface water microbiome communities, with a particular focus on the distribution of genes associated with nitrogen (N) cycling, using shotgun metagenomics sequencing and an assembly-based metagenome approach.Results and discussionFrom 117 surface water samples, we reconstructed 157 metagenome-assembled genomes (MAGs), predominantly from the Patescibacteria superphylum. Brushing alone, conducted about 10 months prior to dredging, had an insignificant impact on the aquatic microbial community. However, dredging led to a significant reduction in community diversity and abundance of genes affiliated with denitrification, dissimilatory nitrate reduction to ammonia, and complete nitrification through comammox. Ditch management resulted in noticeable shifts in the microbial community, evidenced by the enrichment of taxa in Polaromonas, Emticicia, Flectobacillus, and Patescibacteria in the water of the managed ditch sites. The metagenomes of these taxa harbor genes involved in various nitrogen biotransformation pathways. Interestingly, following dredging, the levels of ammonia and ammonium, nitrite, and total Kjeldahl N in the managed ditch did not increase, but significantly decreased; likely due to ditch substrate removal and potentially increased flow efficiency and dilution. Being one of the few studies conducted to date, this study provided unique insights into the consequences of drainage ditch management on freshwater microbiomes involved in N cycling.

Sustainable Livestock Production: Screening Analysis and Pilot Implementation of a Biofilm in Piggery Biofilters for Mitigation of Ammonia and Hydrogen Sulfide Emissions

One of the most noticeable problems associated with the close location of piggeries is gaseous compounds emission. Ammonia and hydrogen sulfide emissions affect the quality of life of people living in the vicinity of such facilities. Among the diverse methods for managing and controlling malodorous substances, biological methods, which involve the utilization of microbiological agents, are widely employed. The use of bacterial strains is a relatively simple, low-cost, and ecological method. The study aimed to conduct a preliminary evaluation of the implementation of a novel consortium of deodorizing bacteria. The study involved the selection of bacteria, assessment of the antagonistic properties, implementation of the inoculum in a mesh-filled biofilter, and analysis of ammonia, hydrogen sulfide, and fine dust content in the air before and after passing through the mature biological bed. The results obtained demonstrate the effectiveness of the biofiltration bed in reducing ammonia levels, with a maximum decrease observed at 73.90%. For hydrogen sulfide, a removal efficiency of &gt;72.08% was observed. Reduction in fine dust pollution also decreased from a level of 3.75 mg/m3 to 1.06 mg/m3. The study’s findings demonstrate the promising potential of utilizing a consortium of deodorizing bacteria as an effective approach to mitigating emissions from piggeries.

Neuroprotective and cognitive enhancing effects of herbecetin against thioacetamide induced hepatic encephalopathy in rats via upregulation of AMPK and SIRT1 signaling pathways

Acute liver injury, there is a risky neurological condition known as hepatic encephalopathy (HE). Herbacetin is a glycosylated flavonoid with many pharmacological characteristics. The purpose of this study was to assess the ability of herbacetin to protect against the cognitive deficits associated with thioacetamide (TAA) rat model and delineate the underlying behavioral and pharmacological mechanisms. Rats were pretreated with herbacetin (20 and 40 mg/kg) for 30days. On 30th day, the rats were injected with TAA (i.p. 350 mg/kg) in a single dose. In addition to a histpathological studies, ultra-structural architecture of the brain, liver functions, oxidative stress biomarkers, and behavioral tests were evaluated. Compared to the TAA-intoxicated group, herbacetin improved the locomotor and cognitive deficits, serum hepatotoxicity indices and ammonia levels. Herbacetin reduced brain levels of malodialdeyde, glutamine synthetase (GS), tumor necrosis factor- alpha (TNF-α), interleukin 1 B (IL-1β), annexin v, and increased brain GSH, Sirtuin 1 (SIRT1), and AMP-activated kinase (AMPK) expression levels. Also, herbacetin improve the histopathological changes and ultra- structure of brain tissue via attenuating the number of inflammatory and apoptotic cells. Herbacetin treatment significantly reduced the toxicity caused by TAA. These findings suggest that herbacetin might be taken into account as a possible neuroprotective and cognitive enhancing agent due to its ability to reduce oxidative stress, inflammation and apoptosis associated with TAA.

Comparative effects of legume‐based intercropping systems involving pigeon pea and cowpea under deep‐bed and conventional tillage systems in Malawi

AbstractLeguminous‐based intercropping, combined with conservation agriculture, is a promising approach to improve soil fertility, crop yields, and sustainable land use for smallholder farmers in sub‐Saharan Africa, including Malawi. This study aimed to assess the effects of incorporating legume‐based intercropping systems involving pigeon pea (Cajanus cajan) and cowpea (Vigna unguiculata) into the deep bed farming (DBF) system promoted by Tiyeni in northern Malawi. The study used a split plot design with cropping systems (CS) as the main plots and tillage systems (TS) as the sub‐plots. All treatments were replicated three times. The study encompassed two cropping seasons, where CS included legume‐based treatments, sole cropped maize (Zea mays) without fertilizer (MZ) and sole cropped maize with 92 kg top dressing N fertilizer per hectare (MZ + 92), while TS included DBF and conventional tillage (CT). The study found that all plots with leguminous crops on both DBF and CT showed higher levels of ammonium (NH4+), nitrate (NO3−) and phosphorus (P) in the soil, but DBF had significantly higher levels over 2 years. Intercropping systems showed higher land productivity (land equivalent ratio &gt; 1) than sole cropping in both years, indicating that legume‐based cropping can improve land use efficiency and yields. It can be noted from this study that intercropping systems based on cereals and legumes, implemented in DBF, has the potential to sustain agricultural intensification in sub‐Saharan African countries where access to chemical fertilizers is limited among smallholder farmers.

Treatment of ornithine transcarbamylase deficiency in a child with glyceryl phenylbutyrate

Glyceryl phenylbutyrate (GPB) serves as a long-term management medication for Ornithine transcarbamylase deficiency (OTCD), effectively controlling hyperammonemia, but there is a lack of experience in using this medicine in China. This article retrospectively analyzes the case of a child diagnosed with OTCD at Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, including a review of related literature. After diagnosis, the patient was treated with GPB, followed by efficacy follow-up and pharmacological monitoring. The 6-year and 6-month-old male patient exhibited poor speech development, disobedience, temper tantrums, and aggressive behavior. Blood ammonia levels peaked at 327 μmol/L; urine organic acid analysis indicated elevated uracil levels; cranial MRI showed extensive abnormal signals in both cerebral hemispheres. Genetic testing revealed de novo mutation in the OTC gene (c.241T>C, p.S81P). Blood ammonia levels were approximately 43, 80, and 56 μmol/L at 1, 2, and 3 months after starting GPB treatment, respectively. During treatment, blood ammonia was well-controlled without drug-related adverse effects. The patient showed improvement in developmental delays, obedience, temperament, and absence of aggressive behavior.

Integrated partial nitrification and Tribonema minus cultivation for cost-effective ammonia recovery and lipid production from slaughterhouse wastewater

High ammonium content in untreated anaerobic digestion (AD) wastewater can inhibit microalgal growth, hindering both bioremediation and biomass/lipid productivity. This study investigated the potential of partial nitrification (PN) as a pretreatment step for AD effluent before cultivating the oleaginous microalga Tribonema minus for bioremediation and lipid production. The PN process transforms inhibitory ammonium into nitrate, a nitrogen form that microalgae can effectively utilize, thereby reducing ammonia toxicity. The results showed remarkable resilience in T. minus, with the species being able to tolerate high ammonium levels (≤120 mg/L) when combined with nitrate in synthetic wastewater. However, when ammonium was the sole nitrogen source (>30 mg/L), its inhibitory effect on T. minus growth became evident. Nevertheless, successful cultivation of T. minus was achieved in PN effluent from slaughterhouse AD using a Sequencing Batch Reactor (SBR) (25 °C and hydraulic retention time (HRT) of 1.5 h) containing 190 mg/L ammonium, achieving 51.25 % lipid accumulation. Additionally, cultivation with 125 mg/L NH4+-N in the PN effluent resulted in removal rates exceeding 95 % for NH4+-N. This approach, therefore, delivered the dual advantage of not only mitigating the environmental risks associated with wastewater but also fostering renewable biomass production for cleaner energy.

Metabolic phenotyping reveals an emerging role of ammonia abnormality in Alzheimer’s disease

The metabolic implications in Alzheimer’s disease (AD) remain poorly understood. Here, we conducted a metabolomics study on a moderately aging Chinese Han cohort (n = 1397; mean age 66 years). Conjugated bile acids, branch-chain amino acids (BCAAs), and glutamate-related features exhibited strong correlations with cognitive impairment, clinical stage, and brain amyloid-β deposition (n = 421). These features demonstrated synergistic performances across clinical stages and subpopulations and enhanced the differentiation of AD stages beyond demographics and Apolipoprotein E ε4 allele (APOE-ε4). We validated their performances in eight data sets (total n = 7685) obtained from Alzheimer’s Disease Neuroimaging Initiative (ADNI) and Religious Orders Study and Memory and Aging Project (ROSMAP). Importantly, identified features are linked to blood ammonia homeostasis. We further confirmed the elevated ammonia level through AD development (n = 1060). Our findings highlight AD as a metabolic disease and emphasize the metabolite-mediated ammonia disturbance in AD and its potential as a signature and therapeutic target for AD.

Touch–based potentiometric sensors for simultaneous detection of urea and ammonium from fingertip sweat

Urea is a biomarker for diagnosis and management of multiple disorders. The measurement of urea could help in the diagnosis of patients with kidney dysfunction. Despite their attractive analytical performances, the existing urea measurement methods are still limited to sophisticated and time–consuming or require invasive blood sampling. Herein, a reliable noninvasive, simple, and disposable touch–based potentiometric sensor is fabricated for rapid monitoring of fingertip sweat urea. Novel touch–based urea detection relies on immobilized urease recognition and a solid–contact ammonium–ion–selective electrode, along with a screen–printed carbon working electrode modified carboxylated carbon nanotubes for enhancing sensor’s sensitivity. The fingertip sweat under sedentary rest conditions can be instantaneously collected on customized porous polyvinyl alcohol hydrogel transporting sweat to working electrode surface where the hydrolysis of urea is catalyzed, generating bicarbonate and ammonium. The resulting ammonium can be detected with ion–selective transducer, enabling indirect monitoring of sweat urea. Potential interference from co–existing ammonium in human sweat is addressed by developing a dual disposable potentiometric sensor, consisting of urea and ammonium sensors on a single strip platform allowing for simultaneous touch–based detection of sweat urea and ammonium. The resulting dual disposable sensing system offers rapid urea and ammonium monitoring within a group of healthy human subjects, along with a good correlation with R2 = 0.974 between the sweat urea and capillary blood urea levels. Additional confirmation among a broad sample of individuals along with the validation of sensor data through centralized laboratory tests will establish the practicality of simultaneously monitoring urea and ammonium levels.

Ammonia Accumulation as a Proxy to Determine Cage-change Frequency in Antelope Ground Squirrels (Ammospermophilus leucurus).

Due to a lack of evidence-based standards for cage-change intervals for antelope ground squirrels (AGS, Ammospermophilus leucurus), we evaluated cage ammonia accumulation in our colony of adult, wild-caught AGS and identified factors that influenced ammonia levels. Intracage ammonia was measured daily in singly housed AGS in static caging that contained a running wheel and 1/2, 3/4, 1, or 2 quart (qt) of corncob bedding. Cages were changed when ammonia levels reached greater than 50ppm, our upper acceptable limit for ammonia based on mouse studies of ammonia aversion and toxicity. We also measured average daily water consumption over 2 wk to examine any correlation between water use and ammonia accumulation. We hypothesized that the desert-dwelling AGS would not reach intracage ammonia levels of greater than 50ppm in a 2-wk interval at any bedding volume. Our data showed that intracage ammonia was highly variable among individuals and was significantly associated with water consumption and bedding volumes. Seventeen percent of AGS on 1/2qt of bedding and 18% on 3/4qt of bedding reached greater than 50ppm ammonia before 7 d. All AGS on 1 and 2qt of bedding remained below 50ppm ammonia for 1 wk. Even when maintained on 2qt of bedding, not all AGS remained below 50ppm ammonia for 2 wk. Therefore, we concluded that the most appropriate option was weekly cage change for singly housed AGS on 1qt of bedding in static caging.

Bacterial DNA Translocation Is Associated With Overt Hepatic Encephalopathy and Mortality in Patients With Cirrhosis.

Data on the relationship between bacterial translocation, hepatic encephalopathy (HE), and mortality are scarce. This study aimed to assess the association between bacterial DNA (bactDNA) translocation, inflammatory response, ammonia levels, and severity of HE in patients with cirrhosis, as well as the role of bactDNA translocation in predicting mortality. Cirrhotic patients without bacterial infection were prospectively enrolled between June 2022 and January 2023. Grading of HE was classified by the West Haven Criteria and Psychometric Hepatic Encephalopathy Score ≤ -5. Overall, 294 cirrhotic patients were enrolled, with 92 (31.3%) and 58 (19.7%) having covert and overt HE, respectively. BactDNA translocation was detected in 36.1% of patients (n = 106). Patients with overt HE had more bactDNA translocation and higher serum lipopolysaccharide-binding protein (LBP), tumor necrosis factor-α, interleukin-6 (IL-6), and ammonia levels than those without HE. Patients with detectable bactDNA had higher white cell counts and serum LBP and IL-6 levels than those without. By contrast, bactDNA, serum LBP, and soluble CD14 levels were comparable between patients with covert HE and those without HE. The multivariate Cox regression analysis revealed that bactDNA translocation (hazard ratio [HR] = 2.49, 95% confidence interval [CI]: 1.22-5.11), Model for End-Stage Liver Disease score (HR = 1.12, 95% CI: 1.09-1.16), age (HR = 1.05, 95% CI: 1.000-1.002), and baseline IL-6 (HR = 1.001, 95% CI: 1.000-1.002) were independent factors associated with 6-month mortality. Apart from hyperammonemia, bactDNA translocation is a possible factor associated with overt HE in cirrhotic patients. BactDNA translocation and IL-6 are independent factors associated with 6-month mortality.