Decomposition Of Uric Acid Research Articles

Bifunctional Fe-MOF@Fe3O4NPs for colorimetric and ratiometric fluorescence detection of uric acid in human urine

Nanozymes as a substitute for natural enzymes have attracted many attention owing to their high stability, low cost, and satisfactory catalytic activity. In this study, a new dual-readout detection strategy was proposed for colorimetric and ratiometric fluorescence detection of uric acid (UA) based on bifunctional metal–organic framework nanocomposite (Fe-MOF@Fe3O4NPs), which functions as fluorescent indicators as well as peroxidase mimics. In the presence of uricase, the decomposition of UA can produce H2O2, and Fe-MOF@Fe3O4NPs catalyzed H2O2 into the OH radicals, which could oxidize o-phenylene-diamine to 2,3-diaminophenazine, accompanied by a fluorescence emission at 600 nm and a UV–vis absorption peak at 450 nm. At the same time, the fluorescence of Fe-MOF@Fe3O4NPs at 460 nmcould be quenched by 2,3-diaminophenazine via Förster resonance energy transfer. Therefore, the fluorescence intensity ratio (I600/I460) and UV–vis absorption intensities are employed to construct the dual-readout biosensor for the determination of UA. The linear range was 0.2–200 μM and the limit of detection for the fluorometric and colorimetric detection were 0.03 μM and 0.18 μM, respectively. Finally, the biosensor was employed to determine UA in urine samples, and satisfactory results were obtained.

Gut Microbiome and Metabolome Variations in Self-Identified Muscle Builders Who Report Using Protein Supplements.

Muscle builders frequently consume protein supplements, but little is known about their effect on the gut microbiota. This study compared the gut microbiome and metabolome of self-identified muscle builders who did or did not report consuming a protein supplement. Twenty-two participants (14 males and 8 females) consumed a protein supplement (PS), and seventeen participants (12 males and 5 females) did not (No PS). Participants provided a fecal sample and completed a 24-h food recall (ASA24). The PS group consumed significantly more protein (118 ± 12 g No PS vs. 169 ± 18 g PS, p = 0.02). Fecal metabolome and microbiome were analyzed by using untargeted metabolomics and 16S rRNA gene sequencing, respectively. Metabolomic analysis identified distinct metabolic profiles driven by allantoin (VIP score = 2.85, PS 2.3-fold higher), a catabolic product of uric acid. High-protein diets contain large quantities of purines, which gut microbes degrade to uric acid and then allantoin. The bacteria order Lactobacillales was higher in the PS group (22.6 ± 49 No PS vs. 136.5 ± 38.1, PS (p = 0.007)), and this bacteria family facilitates purine absorption and uric acid decomposition. Bacterial genes associated with nucleotide metabolism pathways (p < 0.001) were more highly expressed in the No PS group. Both fecal metagenomic and metabolomic analyses revealed that the PS group’s higher protein intake impacted nitrogen metabolism, specifically altering nucleotide degradation.

Upconversion-nanoparticle-functionalized Janus micromotors for efficient detection of uric acid.

We report enzyme-powered upconversion-nanoparticle-functionalized Janus micromotors, which are prepared by immobilizing uricase asymmetrically onto the surface of silicon particles, to actively and rapidly detect uric acid. The asymmetric distribution of uricase on silicon particles allows the Janus micromotors to display efficient motion in urine under the propulsion of biocatalytic decomposition of uric acid and simultaneously detect uric acid based on the luminescence quenching effect of the UCNPs modified on the other side of SiO2. The efficient motion of the motors greatly enhances the interaction between UCNPs and the quenching substrate and improves the uric acid detection efficiency. Overall, such a platform using uric acid simultaneously as the detected substrate and motion fuel offers considerable promise for developing multifunctional micro/nanomotors for a variety of bioassay and biomedical applications.

A climate-dependent global model of ammonia emissions from chicken farming

Abstract. Ammonia (NH3) has significant impacts on the environment, which can influence climate and air quality and cause acidification and eutrophication in terrestrial and aquatic ecosystems. Agricultural activities are the main sources of NH3 emissions globally. Emissions of NH3 from chicken farming are highly dependent on climate, affecting their environmental footprint and impact. In order to investigate the effects of meteorological factors and to quantify how climate change affects these emissions, a process-based model, AMmonia–CLIMate–Poultry (AMCLIM–Poultry), has been developed to simulate and predict temporal variations in NH3 emissions from poultry excretion, here focusing on chicken farms and manure spreading. The model simulates the decomposition of uric acid to form total ammoniacal nitrogen, which then partitions into gaseous NH3 that is released to the atmosphere at an hourly to daily resolution. Ammonia emissions are simulated by calculating nitrogen and moisture budgets within poultry excretion, including a dependence on environmental variables. By applying the model with global data for livestock, agricultural practice and meteorology, we calculate NH3 emissions from chicken farming on a global scale (0.5∘ resolution). Based on 2010 data, the AMCLIM–Poultry model estimates NH3 emissions from global chicken farming of 5.5 ± 1.2 Tg N yr−1, about 13 % of the agriculture-derived NH3 emissions. Taking account of partial control of the ambient environment for housed chicken (layers and broilers), the fraction of excreted nitrogen emitted as NH3 is found to be up to 3 times larger in humid tropical locations than in cold or dry locations. For spreading of manure to land, rain becomes a critical driver affecting emissions in addition to temperature, with the emission fraction being up to 5 times larger in the semi-dry tropics than in cold, wet climates. The results highlight the importance of incorporating climate effects into global NH3 emissions inventories for agricultural sources. The model shows increased emissions under warm and wet conditions, indicating that climate change will tend to increase NH3 emissions over the coming century.

Assessment of Non-Anthropogenic Addition of Uric Acid to a Water Treatment Wetlands

Artificial water-treatment wetlands can reduce nitrogen and phosphorous nutrient concentrations in wastewater effluent to improve water quality and decrease eutrophication in natural waters. The Orlando Easterly Wetlands (OEW) is an engineered wetland that polishes 57 million liters of wastewater per day, lowering the total nitrogen and phosphorous concentrations through biological, physical, and chemical processes. In addition to purifying the water, the wetlands provide habitat for avian, mammalian, reptilian and macroinvertebrate species. Previous research has shown that avian species affect the eutrophication of agricultural reservoirs near their roost. The research herein quantifies uric acid in avian and reptilian excretory product and tracks its concentration profile throughout the OEW over a seven-month period. This measure of the non-anthropogenic contribution to nitrogen within the park includes winter months when large numbers of migratory birds occupy the wetland. The enzymatic decomposition of uric acid and the subsequent fluorimetric analysis were used to quantify uric acid throughout the flow train of the OEW. High concentrations of 2–4 mg/L uric acid were found in the influent, but drastically declined to concentrations below 0.2 mg/L in the effluent.

Abnormal metabolism of gut microbiota reveals the possible molecular mechanism of nephropathy induced by hyperuricemia

The progression of hyperuricemia disease is often accompanied by damage to renal function. However, there are few studies on hyperuricemia nephropathy, especially its association with intestinal flora. This study combines metabolomics and gut microbiota diversity analysis to explore metabolic changes using a rat model as well as the changes in intestinal flora composition. The results showed that amino acid metabolism was disturbed with serine, glutamate and glutamine being downregulated whilst glycine, hydroxyproline and alanine being upregulated. The combined glycine, serine and glutamate could predict hyperuricemia nephropathy with an area under the curve of 1.00. Imbalanced intestinal flora was also observed. Flavobacterium, Myroides, Corynebacterium, Alcaligenaceae, Oligella and other conditional pathogens increased significantly in the model group, while Blautia and Roseburia, the short-chain fatty acid producing bacteria, declined greatly. At phylum, family and genus levels, disordered nitrogen circulation in gut microbiota was detected. In the model group, the uric acid decomposition pathway was enhanced with reinforced urea liver-intestine circulation. The results implied that the intestinal flora play a vital role in the pathogenesis of hyperuricemia nephropathy. Hence, modulation of gut microbiota or targeting at metabolic enzymes, i.e., urease, could assist the treatment and prevention of this disease.

Uric acid lowering effect of Tibetan Medicine RuPeng15 powder in animal models of hyperuricemia

ObjectiveTo evaluate the influence of the Tibetan medicine RuPeng15 powder (RPP15) on uric acid levels, and explore its possible mechanisms of action in hyperuricemic animal models. MethodsHyperuricemic mice were generated by orally administering yeast extract paste twice daily (30 g/kg) for 8 days, to mimic human hyperuricemia induced by high-protein diets. Hyperuricemic rats were generated by intraperitoneal injection of 250 mg/kg potassium oxonate to each animal 1 h before the last oral administration of test compounds, which raised the serum uric acid level by inhibiting the decomposition of uric acid. Levels of uric acid and creatinine in serum and urine were detected by the phosphotungstic acid and picric acid methods respectively, and the activity of xanthine oxidase (XOD) was assayed using a commercial test kit. ResultsRPP15 (0.4, 0.8, 1.2 g/kg) significantly decreased the level of serum uric acid in healthy rats (P < 0.05). Furthermore, hyperuricemic rats treated with RPP15 (0.4, 0.8, 1.2 g/kg) had lower serum uric acid levels (P < 0.05), accompanied by lower urine uric acid (P < 0.05). For the hyperuricemic mice, the levels of uric acid in the serum decreased significantly (P < 0.05) and the activity of XOD in the liver was restored to normal levels after treatment with RPP15 (P <0.05). ConclusionRPP15 (0.4, 0.8, 1.2 g/kg) demonstrated an anti-hyperuricemic effect on both healthy and hyperuricemic animals, and the mechanism is most likely associated with inhibiting the activity of XOD.

Ammonia volatilization after surface application of laying-hen and broiler-chicken manures.

Ammonia (NH) losses after field application of animal manure are affected by manure characteristics. The objectives of this study were to quantify NH losses from poultry manures obtained from varied handling and storage systems commonly found in eastern Canada and to relate NH emissions to manure characteristics. We measured NH volatilization using wind tunnels for 22 d after soil-surface application of seven solid poultry manures originating from farms varying in production type (laying hens and broiler chickens) and in storage duration and conditions. Cumulative emissions (2.7-7.0 g NH-N m) accounted for 13.6 to 35.0% of the total N applied and 51 to 84% (mean, 70%) of the sum of ammoniacal N, urea N, and uric acid N applied (TAUA). On average, 20% of these losses occurred during the first 4.5 h after application for manures that were not dried in the barn shortly after excretion. Production type and storage durations could not explain differences in NH volatilization between manures. Volatilization losses were linearly related to manure dry matter and to manure-derived NH-N, but sources of N changed with time after application. During the first 7 d, variations in total ammoniacal N applied (TANA) among manures explained most of the variations in cumulative NH losses ( = 0.85 after 26 h and 0.92 after 7 d). After a simulated rainfall (5 mm) on Day 7 that stimulated the decomposition of uric acid in manures, TAUA rather than TANA was related to cumulative emissions ( = 0.77 after 14 and 22 d). Our results indicate that reliable estimates of NH volatilization after land spreading of poultry manures should be based not only on TANA but also on NH-N derived from the decomposition of uric acid, that volatilization losses reported in the literature (including the present study) averaged 50% of TAUA, and that estimates for a given situation also need to account for local environmental conditions.

Metabolic Interactions of Purine Derivatives with Human ABC Transporter ABCG2: Genetic Testing to Assess Gout Risk

In mammals, excess purine nucleosides are removed from the body by breakdown in the liver and excretion from the kidneys. Uric acid is the end product of purine metabolism in humans. Two-thirds of uric acid in the human body is normally excreted through the kidney, whereas one-third undergoes uricolysis (decomposition of uric acid) in the gut. Elevated serum uric acid levels result in gout and could be a risk factor for cardiovascular disease and diabetes. Recent studies have shown that human ATP-binding cassette transporter ABCG2 plays a role of renal excretion of uric acid. Two non-synonymous single nucleotide polymorphisms (SNPs), i.e., 421C>A (major) and 376C>T (minor), in the ABCG2 gene result in impaired transport activity, owing to ubiquitination-mediated proteosomal degradation and truncation of ABCG2, respectively. These genetic polymorphisms are associated with hyperuricemia and gout. Allele frequencies of those SNPs are significantly higher in Asian populations than they are in African and Caucasian populations. A rapid and isothermal genotyping method has been developed to detect the SNP 421C>A, where one drop of peripheral blood is sufficient for the detection. Development of simple genotyping methods would serve to improve prevention and early therapeutic intervention for high-risk individuals in personalized healthcare.

Cloning and Expression of a Urate Oxidase and Creatinine Hydrolase Fusion Gene in Escherichia coli

Objective: To construct a plasmid containing a urate oxidase and creatinine hydrolase fusion gene and transform the plasmid into Escherichia coli to decompose uric acid and creatinine. Methods: According to the GenBank data for the urate oxidase gene, specific primers were designed to amplify and remove the stop codon for the urate oxidase gene. The gene was then ligated into the plasmid pMG36e to construct pMG36e-U. Then, using the GenBank database for the creatinine hydrolase gene, primers were designed to amplify the creatinine hydrolase gene. This gene was ligated into pMG36e-U to form pMG36e-U/C. Next, this construct was transformed into E. coli, which was confirmed by screening the recombinant E. coli and sodium dodecylsulfonate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The engineered bacteria were cultured with a specific concentration of creatinine and uric acid for 24 h. Then, the concentrations of creatinine and uric acid in the culture fluid were measured. Results: The recombinant gene fragment was approximately 1.68 kb, and it contained the urate oxidase and creatinine hydrolase genes. The transformed E. coli expressed creatinine hydrolase and uric acid oxidase. The creatinine decomposition rate increased by 43.5%, and the uric acid decomposition rate increased by 42.32%. Conclusion: The constructed recombinant plasmid containing a fusion gene of creatinine hydrolase and uric acid oxidase was transformed into E. coli, and the enzymatic activities were expressed.

Increased total nitrogen content of poultry manure by decreasing water content through composting processes

Microbial mineralization of urea and uric acid in poultry litter can lead to loss of nitrogen (N) content and its value as a fertilizer. To minimize the loss of N in the composting processes, controlling the water content in litters is a key to reduce the mineralization processes of N compounds. The N content of litter may be influenced by diets, hen age and the type of poultry houses used. The objectives of the present study were i) to determine the relationship between the water content and the decomposition rate of uric acid in poultry litter and ii) to investigate the effect of hen age and crude protein (CP) percentages in diets on the N content of poultry litter. A layer feeding trial was conducted in two poultry farms with windowless and open-floor houses. An incubation study of poultry litter was performed under different levels of water content. Our study found that the diet CP percentage (16.5–18%) and the growth stage of laying hens did not have a significant effect on the amount of total N (52–56 g kg−1) and uric acid-N (26–31g kg−1) in fresh litters. At the 7th day of litter incubation study, the concentration of uric acid-N was 22 g kg−1 in litters with a water content of 35%, whereas it further decreased to less than 1.3 g kg−1 in litters with a water content of 55% and higher levels. The decomposition rate of uric acid-N in litter was 0.3–3.1g kg−1 day−1 in the windowless house and 3.1–7.1g kg−1 day−1 in the open-floor house. Decomposition of uric acid in litters was positively correlated to the litter moisture content that is controlled to be lower in windowless houses (40–50%) than in open-floor houses (55–80%) during the composting period. Our study suggests that the use of windowless houses for layer chicken production is effective for producing poultry manure with a high N content.

Effect and Mechanism of Total Saponin of Dioscorea on Animal Experimental Hyperuricemia

In this study, we investigated the effects and mechanisms of Total Saponin of Dioscorea (TSD) on animal experimental hyperuricemia. Mouse and rat hyperuricemic models were made by orally administering yeast extract paste once a day (30 and 20 g/kg, respectively), for 7 days. Yeast would disturb normal purine metabolism by increasing xanthine oxidase (XOD) activity and generating large quantities of uric acid. This model is similar to human hyperuricemia, which is induced by high-protein diets, due to a purine and nucleic acid metabolic disturbance. Another mouse hyperuricemia model was generated by intraperitoneal injection once with uric acid 250 mg/kg or potassium oxonate 300 mg/kg. Potassium oxonate, a urate oxidase inhibitor, can raise the serum uric acid level by inhibiting the decomposition of uric acid. Likewise, injecting uric acid can also increase serum uric acid concentration. The concentration of uric acid in serum or urine was detected by the phosphotungstic acid method, and the activity of XOD was assayed by a test kit. The results showed that TSD (240, 120 and 60 mg/kg, ig) could significantly lower the level of serum uric acid in hyperuricemic mice. TSD (120 and 60 mg/kg, ig) could also lower the level of serum uric acid in hyperuricemic rats, reduce the activity of XOD in the serum and liver of hyperuricemic rats, and increase the level of urine uric acid concentration as well as 24-hour total uric acid excretion. In conclusion, TSD possesses a potent anti-hyperuricemic effect on hyperuricemic animals, and the mechanism may be relevant in accelerating the excretion and decreasing the production of uric acid.

Transthyretin-related proteins function to facilitate the hydrolysis of 5-hydroxyisourate, the end product of the uricase reaction

Purine catabolic pathway in Bacillus subtilis is consisted of more than 14 genes. Among these genes, pucL and pucM are required for uricase activity. While PucL is known to encode the uricase itself, the function of PucM is still unclear although this protein is also indispensable for uric acid decomposition. Here, we provide evidence that PucM, a transthyretin-related protein, functions to facilitate the hydrolysis of 5-hydroxyisourate, the end product of the uricase reaction. Based on these results, we propose that transthyretin-related proteins present in diverse organisms are not functionally related to transthyretin but actually function as a hydroxyisourate hydrolase.

Effects of Dietary Zinc Supplementation on Hen Performance, Ammonia Volatilization, and Nitrogen Retention in Manure

This investigation was undertaken to evaluate the effects of dietary ZnSO4 supplementation on ammonia volatilization and nitrogen retention in hen manure. One hundred twenty, 45-wk-old commercial Leghorn laying hens were sequentially fed diets with 1000, 2000, and 3000 ppm Zn as ZnSO4 (Zn-1000, Zn-2000, and Zn-3000), then followed by two control dietary periods with 114 ppm Zn (Control-1 and Control-2) for a total of five consecutive eight-day experiment periods, respectively. When hens were fed the 1000 and 2000 ppm Zn treatment diets, room ammonia levels were significantly reduced compared to the control diets. Dietary Zn treatments reduced the decomposition of uric acid, resulting in an increase in manure total-N retention compared to the control fed birds. The 1000 ppm Zn supplement had no adverse effects on hen body weight, feed consumption, egg production, egg weight, albumen height, or shell thickness. However, hens fed the diet containing 3000 ppm Zn had significantly depressed body weight, feed consumption, egg production, egg weight, and shell thickness. Zinc levels of egg contents increased linearly as dietary Zn levels increased. These levels in eggs would not be a problem for human consumption because these are much less than the daily Zn recommended dietary allowance. Although land application of such manure will not cause environmental problems or crop toxicity, proper monitoring of soil and crop Zn levels and effective nutrient management planning would be well advised.

Production of an egg yolk antibody specific to microbial uricase and its inhibitory effects on uricase activity

Ammonia gas produced from poultry manure can be a potential source of environmental pollution. Microbial uricase in poultry manure is an important target enzyme to reduce ammonia production because ammonia is mainly generated from the microbial decomposition of uric acid in the manure. Thus, the inhibition of microbial uricase is critical in preventing NH3 volatilization. A potential method of inhibiting uricase activity is the use of antibodies specific to microbial uricase. Therefore, this study was designed to evaluate 1) the production of the uricase-specific egg yolk antibody (IgY) from immunized hens and 2) the effect of the uricase-specific IgY on the activity of uricase. A total of 12 Single Comb White Leghorn hens were injected intramuscularly with uricase from Arthrobacter globiformis. The hens were immunized a second and third time at 1 and 2 wk, respectively, after the initial injection. The production of uricase-specific IgY was first detected at 2 wk after the initial immunization, and levels increased more than threefold at 4 wk. The method including water extraction, ammonium sulfate precipitation, and ethanol precipitation showed the most acceptable IgY purity and over 97% uricase-specific IgY recovery. Finally, the effect of the uricase-specific IgY on uricase activity was determined by a uricase assay. The slope ratio showed that the immune-IgY from the uricase-immunized hens and nonimmune IgY from nonimmunized control hens reduced uricase degradation by 58 and 43%, respectively, compared to the uricase treatment. The regression slope indicated that the immune IgY and nonimmune IgY treatments had a significant inhibitory effects on uricase activity compared to the uricase.

Ammonium in coastal Antarctic aerosol and snow: Role of polar ocean and penguin emissions

Year‐round aerosol samples collected in the boundary layer at coastal Antarctic sites (Dumont D'Urville, Neumayer, and Halley) indicate a seasonal cycle of ammonium concentrations with a minimum in winter (April–September). A large intersite difference appears in the summer (November–February) maxima values, from ∼12.5 ng m−3 at Neumayer to 140–230 ng m−3 at Dumont D'Urville. At Dumont D'Urville, ammonium concentrations are the largest ever reported from Antarctic sites, and the large summer maxima are associated with large enrichments with respect to sea salt for potassium and calcium. In addition, seasonal ammonium variations at Dumont D'Urville are in phase with a well‐marked seasonal cycle of oxalate concentrations which exhibit maxima of 5–10 ng m−3 in spring and summer and minima of less than 0.5 ng m−3 in winter. Such a composition of aerosols present in the boundary layer at Dumont D'Urville in summer is linked to the presence of a large Adélie penguin population from the end of October to March at the site. Ornithogenic soils (defined as guano‐enriched soils), together with the bacterial decomposition of uric acid, are a source of ammonium, oxalate, and cation (such as potassium and calcium) aerosol, in addition to a subsequent large ammonia loss from ornithogenic soils to the atmosphere. The total breeding population of 5 million Adélie penguins widely distributed around the Antarctic continent may emit, at most, some 2.5 × 10−4 Mt of NH3‐N during the summer months. In contrast, Halley and Neumayer Stations are far less exposed to penguin colony emissions. At Neumayer, ammonium concentrations peak from January to March and are in phase with the increase of biogenic sulfur species. Here the NH4+/(MSA + nss SO4−) molar ratio is close to 13% in summer aerosol and to 40% in winter aerosol. Using this summer ratio, which may be related to ammonia and sulfur oceanic emissions occurring south of 50°S in summer and estimated DMS emissions in these regions at this time, we derive an upper limit of 0.064 Mt NH3‐N emitted per year by the high‐latitude Southern Ocean in summer. This study indicates a very limited ammonia neutralization of acidic sulfate aerosols at high southern latitudes, except in the vicinity of ornithogenic soils occupied by large penguin colonies.

Effect of complexation to Cr(III) and Cu(II) on the photodynamic decomposition of uric acid

The ability of Cr 3+ and Cu 2+ to protect uric acid (UA) in the UA complexes CrUA, Cr(UA) 3 and CuUA from undergoing photodynamic degradation sensitized by methylene blue was studied. The rates of photodegradation are in the order: UA⪢CrUA⪢Cr(UA) 3. UA in the copper complex CuUA is completely resistant to photodynamic breakdown under the conditions used. The relative proportions of the major photoproducts of UA, allantoin and urea, are changed markedly in the photodynamic breakdown of CrUA. These effects are characteristic of the CrUA complexes and are not due to the influence of free Cr 3+ ions per se on the photodecomposition. The decomposition of CrUA complexes is discussed in terms of the mechanisms of photodegradation of UA.

Uric acid decomposition in the lower gastrointestinal tract.

Uric acid is the end product of nitrogen metabolism in birds. Despite the very low aqueous solubility of this purine compound, few crystals of uric acid are found in the urine. Instead, uric acid is packaged into small spheres that can pass easily through the duct system of the kidney. After entering the cloaca, these spheres are moved with the urine by antiperistalsis into the rectum and digestive ceca. In the ceca, the uric acid is exposed to a large population of bacteria that can use the uric acid as a metabolic substrate. These bacteria degrade the uric acid to volatile fatty acids (VFA) and ammonia. The VFA are absorbed by the cecal tissue, and the ammonia is incorporated into the production of glutamine. The refluxing of uric acid into the ceca and its subsequent degradation by bacteria provides an effective mechanism for the reclamation of carbon and nitrogen from the urine.

Cecal degradation of uric acid in Gambel quail.

In birds, urine enters the lower gastrointestinal tract from paired ureters and can be moved in a retrograde fashion into the colon and digestive ceca. As a major constituent of urine, uric acid is carried into these regions of the gastrointestinal tract. In these locations the chemical composition of the urine, including uric acid, could be altered. To examine this possibility the postrenal degradation of uric acid in the hindgut (ceca, colon, and ileum) of the Gambel quail (Callipepla gambelii) was investigated in vitro to determine the location of activity and the possible source of uricolytic enzymes. Significant breakdown of uric acid was observed in all cecal preparations; only minor amounts were degraded in the ileum and colon. The cecal degradation amounted to 15-49% of the uric acid estimated to be produced by the quail. Attempts to demonstrate uric acid decomposition by bacteria cultured from ceca gave inconclusive results.

High-performance liquid chromatographic isolation of uric acid from soil for isotopic determination

Uric acid was extracted from soil into potassium phosphate solution and isolated from other components by high-performance liquid chromatography, then the isolated fraction was subjected to nitrogen isotope analysis. Studies of the adsorption of uric acid on clay indicated no significant isotope fractionation during the exchange reaction; hence the isotope ratio found in the extract was the same as that in the soil. An increase in soil ammonia content followed the decomposition of uric acid. No uric acid isotopic preference by uric acid bacteria during the decomposition was found. The fractionation at the time of ammonia evaporation was mainly responsible for the high nitrogen isotope ratio in bird rookeries. An extremely high ratio for soil ammonia was found in a simulation experiment. This phenomenon may be mimicked in nature.