Effects of dietary supplementation of rumen-protected folic acid on rumen fermentation, degradability and excretion of urinary purine derivatives in growing steers.

PubMed

Wang, Cong; Liu, Qiang; Guo, Gang; Huo, WenJie; Ma, Le; Zhang, YanLi; Pei, CaiXia; Zhang, ShuanLin; Wang, Hao

2016-12-01

The present experiment was undertaken to determine the effects of dietary addition of rumen-protected folic acid (RPFA) on ruminal fermentation, nutrient degradability, enzyme activity and the relative quantity of ruminal cellulolytic bacteria in growing beef steers. Eight rumen-cannulated Jinnan beef steers averaging 2.5 years of age and 419 ± 1.9 kg body weight were used in a replicated 4 × 4 Latin square design. The four treatments comprised supplementation levels of 0 (Control), 70, 140 and 210 mg RPFA/kg dietary dry matter (DM). On DM basis, the ration consisted of 50% corn silage, 47% concentrate and 3% soybean oil. The DM intake (averaged 8.5 kg/d) was restricted to 95% of ad libitum intake. The intake of DM, crude protein (CP) and net energy for growth was not affected by treatments. In contrast, increasing RPFA supplementation increased average daily gain and the concentration of total volatile fatty acid and reduced ruminal pH linearly. Furthermore, increasing RPFA supplementation enhanced the acetate to propionate ratio and reduced the ruminal ammonia N content linearly. The ruminal effective degradability of neutral detergent fibre from corn silage and CP from concentrate improved linearly and was highest for the highest supplementation levels. The activities of cellobiase, xylanase, pectinase and α-amylase linearly increased, but carboxymethyl-cellulase and protease were not affected by the addition of RPFA. The relative quantities of Butyrivibrio fibrisolvens, Ruminococcus albus, Ruminococcus flavefaciens and Fibrobacter succinogenes increased linearly. With increasing RPFA supplementation levels, the excretion of urinary purine derivatives was also increased linearly. The present results indicated that the supplementation of RPFA improved ruminal fermentation, nutrient degradability, activities of microbial enzymes and the relative quantity of the ruminal cellulolytic bacteria in a dose-dependent manner. According to the conditions of this experiment, the optimum supplementation level of RPFA was 140 mg/kg DM.

Effect of sauna bathing and beer ingestion on plasma concentrations of purine bases.

PubMed

Yamamoto, Tetsuya; Moriwaki, Yuji; Ka, Tuneyoshi; Takahashi, Sumio; Tsutsumi, Zenta; Cheng, Jidong; Inokuchi, Taku; Yamamoto, Asako; Hada, Toshikazu

2004-06-01

To determine whether sauna bathing alone or in combination with beer ingestion increases the plasma concentration of uric acid, 5 healthy subjects were tested. Urine and plasma measurements were performed before and after each took a sauna bath, ingested beer, and ingested beer just after taking a sauna bath, with a 2-week interval between each activity. Sauna bathing alone increased the plasma concentrations of uric acid and oxypurines (hypoxanthine and xanthine), and decreased the urinary and fractional excretion of uric acid, while beer ingestion alone increased the plasma concentrations and urinary excretion of uric acid and oxypurines. A combination of both increased the plasma concentration of uric acid and oxypurines, and decreased the urinary and fractional excretion of uric acid, with an increase in the urinary excretion of oxypurines. The increase in plasma concentration of uric acid with the combination protocol was not synergistic as compared to the sum of the increases by each alone. Body weight, urine volume, and the urinary excretion of sodium and chloride via dehydration were decreased following sauna bathing alone. These results suggest that sauna bathing had a relationship with enhanced purine degradation and a decrease in the urinary excretion of uric acid, leading to an increase in the plasma concentration of uric acid. Further, we concluded that extracellular volume loss may affect the common renal transport pathway of uric acid and xanthine. Therefore, it is recommended that patients with gout refrain from drinking alcoholic beverages, including beer, after taking a sauna bath, since the increase in plasma concentration of uric acid following the combination of sauna bathing and beer ingestion was additive.

Effects of topiroxostat and febuxostat on urinary albumin excretion and plasma xanthine oxidoreductase activity in db/db mice.

PubMed

Nakamura, Takashi; Murase, Takayo; Nampei, Mai; Morimoto, Nobutaka; Ashizawa, Naoki; Iwanaga, Takashi; Sakamoto, Ryusuke

2016-06-05

Topiroxostat, a xanthine oxidoreductase (XOR) inhibitor, has been shown to decrease the urinary albumin-to-creatinine ratio compared with placebo in hyperuricemic patients with stage 3 chronic kidney disease. Thus, we aimed to ascertain the albuminuria-lowering effect of topiroxostat in diabetic mouse. Db/db mice were fed standard diets with or without topiroxostat (0.1, 0.3, 1, and 3mg/kg/day) and febuxostat (0.1, 0.3, and 1mg/kg/day) for four weeks. Urinary albumin and purine bodies levels, XOR activities, and drug concentrations in the liver, kidney, and plasma were measured. Moreover, the XOR inhibitory activity of each XOR inhibitor was evaluated with or without an exogenous protein in vitro. Topiroxostat decreased dose-dependently the urinary albumin excretion, but febuxostat did not show such a tendency. Treatment with topiroxostat inhibited plasma XOR activity with dose-dependent increase in plasma purine levels, which was not observed by febuxostat. Pharmacokinetic/pharmacodynamic analysis revealed that topiroxostat and febuxostat concentration in each tissue showed a good correlation with both the hypouricemic effect and plasma drug concentration, whereas the change in albuminuria correlated neither with the change in uric acid nor with drug concentration in plasma. However, the change in urinary albumin and plasma XOR activity showed good correlation in topiroxostat group. The 50% inhibitory concentration (IC50 value) of febuxostat against plasma XOR in vitro was 12-fold higher than that of topiroxostat, and increased by approximately 13-fold by interfering with an exogenous protein. Topiroxostat caused reduced urinary albumin excretion, in which potent inhibition of the plasma XOR activity might be involved. Copyright © 2016 Elsevier B.V. All rights reserved.

Functionalized Solid Electrodes for Electrochemical Biosensing of Purine Nucleobases and Their Analogues: A Review

PubMed Central

Sharma, Vimal Kumar; Jelen, Frantisek; Trnkova, Libuse

2015-01-01

Interest in electrochemical analysis of purine nucleobases and few other important purine derivatives has been growing rapidly. Over the period of the past decade, the design of electrochemical biosensors has been focused on achieving high sensitivity and efficiency. The range of existing electrochemical methods with carbon electrode displays the highest rate in the development of biosensors. Moreover, modification of electrode surfaces based on nanomaterials is frequently used due to their extraordinary conductivity and surface to volume ratio. Different strategies for modifying electrode surfaces facilitate electron transport between the electrode surface and biomolecules, including DNA, oligonucleotides and their components. This review aims to summarize recent developments in the electrochemical analysis of purine derivatives, as well as discuss different applications. PMID:25594595

Effect of dietary Quebracho tannin extract on feed intake, digestibility, excretion of urinary purine derivatives and milk production in dairy cows.

PubMed

Henke, Anika; Dickhoefer, Uta; Westreicher-Kristen, Edwin; Knappstein, Karin; Molkentin, Joachim; Hasler, Mario; Susenbeth, Andreas

2017-02-01

The aim of this study was to evaluate the effects of dietary Quebracho tannin extract (QTE) on feed intake, apparent total tract digestibility (ATTD), excretion of urinary purine derivatives (PD) and milk composition and yield in dairy cows. Fifty Holstein cows were divided into two groups. To reach a similar performance of both groups, cows were divided according to their milk yield, body weight, days in milk and number of lactations at the start of the experiment averaging 33.2 ± 8.2 kg/d, 637 ± 58 kg, 114 ± 73 d and 2.3 ± 1.6 lactations, respectively. The cows were fed a basal diet as total mixed ration containing on dry matter (DM) basis 34% grass silage, 32% maize silage and 34% concentrate feeds. Three dietary treatments were tested, the control (CON, basal diet without QTE), QTE 15 (basal diet with QTE at 15 g/kg DM) and QTE 30 (basal diet with QTE at 30 g/kg DM). Two treatments were arranged along six periods each 21 d (13 d adaptation phase and 8 d sampling phase). The ATTD of DM and organic matter were reduced only in Diet QTE 30 , whereas both QTE treatments reduced ATTD of fibre and nitrogen (N), indicating that QTE impaired rumen fermentation. Nevertheless, feed intake was unaffected by QTE. In Diet CON, urinary N excretion accounted for 29.8% of N intake and decreased in treatments QTE 15 and QTE 30 to 27.5% and 17.9%, respectively. Daily faecal N excretion increased in treatments CON, QTE 15 and QTE 30 from 211 to 237 and 273 g/d, respectively, which amounted to 39.0%, 42.4% and 51.7% of the N intake, respectively. Hence, QTE shifted N excretion from urine to faeces, whereas the proportion of ingested N appearing in milk was not affected by QTE (average 30.7% of N intake). Daily PD excretion as indicator for microbial crude protein (CP) flow at the duodenum decreased in treatment QTE 30 compared with Diet CON from 413 to 280 mmol/d. The ratios of total PD to creatinine suggest that urinary PD excretion was already lower when feeding Diet QTE 15 . While there was no effect of Diet QTE 15 , treatment QTE 30 reduced milk yield, milk fat and protein. Both QTE treatments reduced milk urea concentration, which suggest that ruminal degradation of dietary CP was reduced. In summary, adding QTE at dosages of 15 and 30 g/kg DM to diets of lactating dairy cows to improve feed and protein use efficiency is not recommended.

Utilization of 2,6-diaminopurine by Salmonella typhimurium.

PubMed Central

Garber, B B; Gots, J S

1980-01-01

The pathway for the utilization of 2,6-diaminopurine (DAP) as an exogenous purine source in Salmonella typhimurium was examined. In strains able to use DAP as a purine source, mutant derivatives lacking either purine nucleoside phosphorylase or adenosine deaminase activity lost the ability to do so. The implied pathway of DAP utilization was via its conversion to DAP ribonucleoside by purine nucleoside phosphorylase, followed by deamination to guanosine by adenosine deaminase. Guanosine can then enter the established purine salvage pathways. In the course of defining this pathway, purine auxotrophs able to utilize DAP as sole purine source were isolated and partially characterized. These mutants fell into several classes, including (i) strains that only required an exogenous source of guanine nucleotides (e.g., guaA and guaB strains); (ii) strains that had a purF genetic lesion (i.e., were defective in alpha-5-phosphoribosyl 1-pyrophosphate amidotransferase activity); and (iii) strains that had constitutive levels of purine nucleoside phosphorylase. Selection among purine auxotrophs blocked in the de novo synthesis of inosine 5'-monophosphate, for efficient growth on DAP as sole source of purine nucleotides, readily yielded mutants which were defective in the regulation of their deoxyribonucleoside-catabolizing enzymes (e.g., deoR mutants). PMID:6782081

Synthesis of Purine Nucleoside and Nucleotide Analogs as Antiparasitic Agents.

DTIC Science & Technology

1979-09-01

was to conduct studies on the synthesis of purine nucleoside and nucleotide analogs as anti- parasitic agents. The primary target compounds were 5...antiparasitic agents. - Jaffe has proposed that the susceptibility of pathogenic helminths and protozoa to fraudulent purine, in contrast to pyrimidine...8217-substituted derivatives are thus designed to inhibit nucleoside and nucleotide kinases as well as other parasitic enzymes. Mammalian cells, onthe

Urinary metabolomics of young Italian autistic children supports abnormal tryptophan and purine metabolism.

PubMed

Gevi, Federica; Zolla, Lello; Gabriele, Stefano; Persico, Antonio M

2016-01-01

Autism spectrum disorder (ASD) is still diagnosed through behavioral observation, due to a lack of laboratory biomarkers, which could greatly aid clinicians in providing earlier and more reliable diagnoses. Metabolomics on human biofluids provides a sensitive tool to identify metabolite profiles potentially usable as biomarkers for ASD. Initial metabolomic studies, analyzing urines and plasma of ASD and control individuals, suggested that autistic patients may share some metabolic abnormalities, despite several inconsistencies stemming from differences in technology, ethnicity, age range, and definition of "control" status. ASD-specific urinary metabolomic patterns were explored at an early age in 30 ASD children and 30 matched controls (age range 2-7, M:F = 22:8) using hydrophilic interaction chromatography (HILIC)-UHPLC and mass spectrometry, a highly sensitive, accurate, and unbiased approach. Metabolites were then subjected to multivariate statistical analysis and grouped by metabolic pathway. Urinary metabolites displaying the largest differences between young ASD and control children belonged to the tryptophan and purine metabolic pathways. Also, vitamin B 6 , riboflavin, phenylalanine-tyrosine-tryptophan biosynthesis, pantothenate and CoA, and pyrimidine metabolism differed significantly. ASD children preferentially transform tryptophan into xanthurenic acid and quinolinic acid (two catabolites of the kynurenine pathway), at the expense of kynurenic acid and especially of melatonin. Also, the gut microbiome contributes to altered tryptophan metabolism, yielding increased levels of indolyl 3-acetic acid and indolyl lactate. The metabolic pathways most distinctive of young Italian autistic children largely overlap with those found in rodent models of ASD following maternal immune activation or genetic manipulations. These results are consistent with the proposal of a purine-driven cell danger response, accompanied by overproduction of epileptogenic and excitotoxic quinolinic acid, large reductions in melatonin synthesis, and gut dysbiosis. These metabolic abnormalities could underlie several comorbidities frequently associated to ASD, such as seizures, sleep disorders, and gastrointestinal symptoms, and could contribute to autism severity. Their diagnostic sensitivity, disease-specificity, and interethnic variability will merit further investigation.

Nitrate but not tea saponin feed additives decreased enteric methane emissions in nonlactating cows.

PubMed

Guyader, J; Eugène, M; Doreau, M; Morgavi, D P; Gérard, C; Loncke, C; Martin, C

2015-11-01

Tea saponin is considered a promising natural compound for reducing enteric methane emissions in ruminants. A trial was conducted to study the effect of this plant extract fed alone or in combination with nitrate on methane emissions, total tract digestive processes, and ruminal characteristics in cattle. The experiment was conducted as a 2 × 2 factorial design with 4 ruminally cannulated nonlactating dairy cows. Feed offer was restricted to 90% of voluntary intake and diets consisted of (DM basis): 1) control (CON; 50% hay and 50% pelleted concentrates), 2) CON with 0.5% tea saponin (TEA), 3) CON with 2.3% nitrate (NIT), and 4) CON with 0.5% tea saponin and 2.3% nitrate (TEA+NIT). Tea saponin and nitrate were included in pelleted concentrates. Diets contained similar amounts of CP (12.2%), starch (26.0%), and NDF (40.1%). Experimental periods lasted 5 wk including 2 wk of measurement (wk 4 and 5), during which intake was measured daily. In wk 4, daily methane emissions were quantified for 4 d using open circuit respiratory chambers. In wk 5, total tract digestibility, N balance, and urinary excretion of purine derivatives were determined from total feces and urine collected separately for 6 d. Ruminal fermentation products and protozoa concentration were analyzed from samples taken after morning feeding for 2 nonconsecutive days in wk 5. Tea saponin and nitrate supplementation decreased feed intake ( < 0.05), with an additive effect when fed in combination. Compared with CON, tea saponin did not modify methane emissions (g/kg DMI; > 0.05), whereas nitrate-containing diets (NIT and TEA+NIT) decreased methanogenesis by 28%, on average ( < 0.001). Total tract digestibility, N balance, and urinary excretion of purine derivatives were similar among diets. Ruminal fermentation products were not affected by tea saponin, whereas nitrate-containing diets increased acetate proportion and decreased butyrate proportion and ammonia concentration ( < 0.05). Under the experimental conditions tested, we confirmed the antimethanogenic effect of nitrate, whereas tea saponin alone included in pelleted concentrates failed to decrease enteric methane emissions in nonlactating dairy cows.

Replacing maize silage plus soybean meal with red clover silage plus wheat in diets for lactating dairy cows.

PubMed

Schulz, Franziska; Westreicher-Kristen, Edwin; Knappstein, Karin; Molkentin, Joachim; Susenbeth, Andreas

2018-02-01

The objectives of this study were to evaluate the effects of replacing maize silage plus soybean meal with red clover silage (RCS) plus wheat on feed intake, diet digestibility, N partitioning, urinary excretion of purine derivatives, and milk production in dairy cows. Forty-four lactating German Holstein cows were used in a 4 × 4 Latin square design with 21-d periods composed of a 13-d adaptation phase followed by an 8-d sampling phase. Experimental diets offered as total mixed ration consisted of a constant forage-to-concentrate ratio (75:25) with targeted proportions of RCS-to-maize silage of 15:60 (RCS 15 ), 30:45 (RCS 30 ), 45:30 (RCS 45 ), and 60:15 (RCS 60 ) on a dry matter (DM) basis. Increasing the proportion of RCS plus wheat in the diet decreased linearly the intake of DM from 22.4 to 19.8 kg/d, and of organic matter from 21.1 to 18.1 kg/d. The apparent total tract digestibility (ATTD) of DM and organic matter did not differ across diets and averaged 68.4 and 70.5%, respectively. However, ATTD of N decreased linearly from 68.5 to 63.2%, whereas ATTD of neutral detergent fiber and acid detergent fiber increased linearly from 50.4 to 59.6% and from 48.4 to 57.7%, respectively, when increasing the proportion of RCS plus wheat. Fecal N excretion increased from 31.6 (RCS 15 ) to 37.2% (RCS 60 ) of N intake, whereas urinary N excretion was the lowest (32.8% of N intake) with RCS 45 . Hence, N efficiency (milk N/N intake) decreased linearly with incremental levels of RCS plus wheat, being the lowest when feeding RCS 60 (25.4%), probably due to increased nonprotein N proportion in total dietary N. Urinary excretion of purine derivatives decreased linearly from 378 to 339 mmol/d, which suggests that increasing levels of RCS plus wheat reduced the microbial crude protein flow at the duodenum. Milk yield and milk protein concentration declined linearly from 35.9 to 30.2 kg/d and from 3.20 to 3.01%, respectively, when increasing the proportion of RCS plus wheat. In conclusion, caution should be taken before introducing high levels of RCS plus wheat in diets of high-yielding dairy cows. However, RCS plus wheat can be included up to 30% of the dairy cow diet (DM basis) without a reduction in lactation performance. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Use of biological fluids for the rapid diagnosis of potentially lethal inherited disorders of human purine and pyrimidine metabolism.

PubMed

Morris, G S; Simmonds, H A; Davies, P M

1986-06-01

Inherited purine and pyrimidine disorders may be associated with serious, sometimes life-threatening consequences. Early and accurate diagnosis is essential. Difficulties encountered when using existing high pressure liquid chromatographic (HPLC) methods led to the development of an improved method based on prior fractionation of urine. The advantages are as follows. 1. Production of fingerprints demonstrating altered urinary excretion patterns characteristic of any one of ten different disorders, in 30 minutes. 2. Positive identification and quantification by comparison with established methods (using conventional chromatography, electrophoresis and UV spectrophotometry) in addition to specific retention times and characteristic UV absorbance ratios at two separate wavelengths (245 and 280 nm) by HPLC. 3. Direct analysis of all the purines and pyrimidines normally found in human body fluids as well as identification of abnormal compounds. 4. Short time between successive analyses while maintaining excellent resolution between compounds of interest and column longevity. 5. Improved separation of the different adenine-based compounds encountered in some disorders, plus demonstration of potential interference by dietary or drug metabolites. 6. Applicability to the monitoring of therapy involving a variety of different purine and pyrimidine analogues. Particular attention should be paid to sample preparation. Plasma profiles will confirm the diagnosis in some, but not all, of these disorders.

Synthesis of some glycoside analogs and related compounds from 9-amino-6-(methylthio)-9H-purine.

PubMed

Temple, C; Kussner, C L; Montgomery, J A

1975-12-01

Additional information on the anticancer activity of 9-amino-9H-purine-6(1H)-thione and its derivatives was sought by the synthesis of some 9-(substituted amino)-6-(methylthio)-9H-purines in which the 9-substituent contained functional groups capable of either reversible or irreversible binding with an enzymatic site. Condensation of 9-amino-6-(methylthio)-9H-purine (1) with some carbonyl compounds followed by hydride reduction of the azomethine linkage in the intermediates leads to the 2-pyrrolylmethyl (8), 2,3,4-trihydroxybutyl (10), and the 1,5-dihydroxy-2- and 3-pentyl (11 and 12) compounds. A 4-hydroxybutyl derivative (13) was obtained by alkylation of 18, the 9-acetyl derivative of 1, with 4-chlorobutyl acetate followed by saponification. The cyclization of 13 and 11 with a sulfonyl chloride gave the 9-pyrrolidin-1-yl (27) and the 9-[2-(tosyloxymethyl)pyrrolidin-1-yl] (28), respectively. Acylation of 1 with ethyl L-2-pyrrolidine-5-carboxylate and ethyl 1-methyl-5-pyrrolidone-3-carboxylate, respectively, in Me2SO containing NaH gave the corresponding amides 15 and 17. Alkylation of 18 with 1-bromo-2-chloroethane and epichlorohydrin gave the N-(2-chloroethyl) and N-(1,2-epoxy-3-propyl) derivatives 19 and 20. The chloro group of the chlorobutyl derivative of 18 was displaced with KSCN and NaN3, respectively, to give the thiocyanate and azido derivatives 23 and 24. Hydrogenation of the latter gave the amine (25), which was acylated with ethyl chloroformate to give the (ethoxycarbonyl)amino compound 26. None of these compounds showed activity against L1210 leukemia cells implanted ip in mice on a single-dose schedule, suggesting that the activity observed in the simpler 9-aminopurines resulted from cleavage of the hydrazino linkage to give pH-purine-6(1H)-thione.

Effect on production of replacing dietary starch with sucrose in lactating dairy cows.

PubMed

Broderick, G A; Luchini, N D; Reynal, S M; Varga, G A; Ishler, V A

2008-12-01

Replacing dietary starch with sugar has been reported to improve production in dairy cows. Two sets of 24 Holstein cows averaging 41 kg/d of milk were fed a covariate diet, blocked by days in milk, and randomly assigned in 2 phases to 4 groups of 6 cows each. Cows were fed experimental diets containing [dry matter (DM) basis]: 39% alfalfa silage, 21% corn silage, 21% rolled high-moisture shelled corn, 9% soybean meal, 2% fat, 1% vitamin-mineral supplement, 7.5% supplemental nonstructural carbohydrate, 16.7% crude protein, and 30% neutral detergent fiber. Nonstructural carbohydrates added to the 4 diets were 1) 7.5% corn starch, 0% sucrose; 2) 5.0% starch, 2.5% sucrose; 3) 2.5% starch, 5.0% sucrose; or 4) 0% starch, 7.5% sucrose. Cows were fed the experimental diets for 8 wk. There were linear increases in DM intake and milk fat content and yield, and linear decreases in ruminal concentrations of ammonia and branched-chain volatile fatty acids, and urinary excretion of urea-N and total N, and urinary urea-N as a proportion of total N, as sucrose replaced corn starch in the diet. Despite these changes, there was no effect of diet on microbial protein formation, estimated from total purine flow at the omasum or purine derivative excretion in the urine, and there were linear decreases in both milk/DM intake and milk N/N-intake when sucrose replaced dietary starch. However, expressing efficiency as fat-corrected milk/DM intake or solids-corrected milk/DM intake indicated that there was no effect of sucrose addition on nutrient utilization. Replacing dietary starch with sucrose increased fat secretion, apparently via increased energy supply because of greater intake. Positive responses normally correlated with improved ruminal N efficiency that were altered by sucrose feeding were not associated with increased protein secretion in this trial.

Design and synthesis of chalcone derivatives as potential non-purine xanthine oxidase inhibitors.

PubMed

Bui, Trung Huu; Nguyen, Nhan Trung; Dang, Phu Hoang; Nguyen, Hai Xuan; Nguyen, Mai Thanh Thi

2016-01-01

Based on some previous research, the chalcone derivatives exhibited potent xanthine oxidase inhibitory activity, e.g. sappanchalcone ( 7 ), with IC 50 value of 3.9 μM, was isolated from Caesalpinia sappan . Therefore, objectives of this research are design and synthesis of 7 and other chalcone derivatives by Claisen-Schmidt condensation and then evaluate their XO inhibitory activity. Fifteen chalcone derivatives were synthesized by Claisen-Schmidt condensation, and were evaluated for XO inhibitory activity. Nine out of 15 synthetic chalcones showed inhibitory activity ( 3 ; 5 - 8 ; 10 - 13 ). Sappanchalcone derivatives ( 11 ) (IC 50 , 2.5 μM) and a novel chalcone ( 13 ) (IC 50 , 2.4 μM) displayed strong xanthine oxidase inhibitory activity that is comparable to allopurinol (IC 50 , 2.5 μM). The structure-activity relationship of these chalcone derivatives was also presented. It is the first research on synthesis sappanchalcone ( 7 ) by Claisen-Schmidt condensation. The overall yield of this procedure was 6.6 %, higher than that of reported procedure (4 %). Design, synthesis, and evaluation of chalcone derivatives were carried out. This result suggests that the chalcone derivative can be used as potential non-purine XO inhibitors.Graphical abstractThe chalcone derivatives as potential non-purine xanthine oxidase inhibitors.

TD-DFT investigation of the magnetic circular dichroism spectra of some purine and pyrimidine bases of nucleic acids.

PubMed

Fahleson, Tobias; Kauczor, Joanna; Norman, Patrick; Santoro, Fabrizio; Improta, Roberto; Coriani, Sonia

2015-05-28

We present a computational study of the magnetic circular dichroism (MCD) spectra in the 200-300 nm wavelength region of purine and its derivative hypoxanthine, as well as of the pyrimidine bases of nucleic acids uracil, thymine, and cytosine, using the B3LYP and CAM-B3LYP functionals. Solvent effects are investigated within the polarizable continuum model and by inclusion of explicit water molecules. In general, the computed spectra are found to be in good agreement with the experimental ones, apart from some overall blue shifts. Both the pseudo-A term shape of the MCD spectra of the purines and the B term shape of the spectra of pyrimidine bases are reproduced. Our calculations also correctly reproduce the reversed phase of the MCD bands in purine compared to that of its derivatives present in nucleic acids. Solvent effects are sizable and system specific, but they do not in general alter the qualitative shape of the spectra. The bands are dominated by the bright π → π* transitions, and our calculations in solution nicely reproduce their energy differences, improving the estimates obtained in the gas phase. Shoulders are predicted for purine and uracil due to n → π* excitations, but they are too weak to be observed in the experiment.

Purine derivatives as potent Bruton’s tyrosine kinase (BTK) inhibitors for autoimmune diseases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Qing; Tebben, Andrew; Dyckman, Alaric J.

Investigation of various heterocyclic core isosteres of imidazopyrazines 1 & 2 yielded purine derivatives 3 & 8 as potent and selective BTK inhibitors. Subsequent SAR studies of the purine series led to the discovery of 20 as a leading compound. Compound 20 is very selective when screened against a panel of 400 kinases and is a potent inhibitor in cellular assays of human B cell function including B-Cell proliferation and CD86 cell surface expression and exhibited in vivo efficacy in a mouse PCA model. Its X-ray co-crystal structure with BTK shows that the high selectivity is gained from filling amore » BTK specific lipophilic pocket. However, physical and ADME properties leading to low oral exposure hindered further development.« less

Study on the activity of non-purine xanthine oxidase inhibitor by 3D-QSAR modeling and molecular docking

NASA Astrophysics Data System (ADS)

Li, Peizhen; Tian, Yueli; Zhai, Honglin; Deng, Fangfang; Xie, Meihong; Zhang, Xiaoyun

2013-11-01

Non-purine derivatives have been shown to be promising novel drug candidates as xanthine oxidase inhibitors. Based on three-dimensional quantitative structure-activity relationship (3D-QSAR) methods including comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA), two 3D-QSAR models for a series of non-purine xanthine oxidase (XO) inhibitors were established, and their reliability was supported by statistical parameters. Combined 3D-QSAR modeling and the results of molecular docking between non-purine xanthine oxidase inhibitors and XO, the main factors that influenced activity of inhibitors were investigated, and the obtained results could explain known experimental facts. Furthermore, several new potential inhibitors with higher activity predicted were designed, which based on our analyses, and were supported by the simulation of molecular docking. This study provided some useful information for the development of non-purine xanthine oxidase inhibitors with novel structures.

Serotonin transporter activity of imidazolidine-2,4-dione and imidazo[2,1-f]purine-2,4-dione derivatives in aspect of their acid-base properties.

PubMed

Zagórska, Agnieszka; Czopek, Anna; Pawłowski, Maciej; Dybała, Małgorzata; Siwek, Agata; Nowak, Gabriel

2012-11-01

Affinities of arylpiperazinylalkyl derivatives of imidazo[2,1-f]purine-2,4-dione and imidazolidine-2,4-dione for serotonin transporter and their acid-base properties were evaluated. The dissociation constant (pK(a)) of compounds 1-22 were determinated by potentiometric titration and calculated using pKalc 3.1 module of the Pallas system. The data from experimental methods and computational calculations were compared and suitable conclusions were reached.

Effects of dietary protein levels and 2-methylbutyrate on ruminal fermentation, nutrient degradability, bacterial populations and urinary purine derivatives in Simmental steers.

PubMed

Wang, C; Liu, Q; Guo, G; Huo, W J; Pei, C X; Zhang, S L; Yang, W Z

2018-06-01

The objective of this study was to evaluate the effects of dietary crude protein (CP) levels and 2-methylbutyrate (MB) supplementation on ruminal fermentation, bacterial populations, microbial enzyme activity and urinary excretion of purine derivatives (PD) in Simmental steers. Eight ruminally cannulated Simmental steers, averaging 18 months of age and 465 ± 8.6 kg of body weight (BW), were used in a replicated 4 × 4 Latin square design by a 2 × 2 factorial arrangement. Low protein (98.5 g CP/kg dry matter [LP] or high protein (128.7 g CP/kg dry matter [HP]) diets were fed with MB supplementation (0 g [MB-] or 16.8 g steer -1  day -1 [MB+]). Steers were fed a total mixed ration with dietary corn straw to concentrate ratio of 50:50 (dry matter [DM] basis). The CP × MB interaction was observed for ruminal total VFA, molar proportions of acetate and propionate, acetate to propionate ratio, ammonia-N, effective degradability of neutral detergent fibre (NDF) and CP, microbial enzyme activity, bacterial populations and total PD excretion (p < .05). Ruminal pH decreased (p < .05), but ruminal total VFA concentration increased (p < .05) with increasing dietary CP level or MB supplementation. Acetate molar proportion increased (p = .043) with MB supplementation, but was not affected by dietary CP level. Propionate molar proportion decreased (p < .05) with increasing dietary CP level or MB supplementation. Consequently, acetate-to-propionate ratio increased (p = .001) with MB supplementation, but was not affected by dietary CP level. Ruminal ammonia-N content increased (p = .034) with increasing dietary CP level, but decreased (p = .012) with MB supplementation. The effective degradability of NDF and CP increased (p < .05) with increasing dietary CP level or MB supplementation. Microbial enzyme activity, bacterial populations and total PD excretion also increased (p < .05) with increasing dietary CP level or MB supplementation. The results indicated that ruminal fermentation, nutrient degradability, microbial enzyme activity, ruminal bacterial populations and microbial protein synthesis improved with increasing dietary CP level or MB supplementation in steers. © 2017 Blackwell Verlag GmbH.

Effects of concentrate-to-forage ratios and 2-methylbutyrate supplementation on ruminal fermentation, bacteria abundance and urinary excretion of purine derivatives in Chinese Simmental steers.

PubMed

Wang, C; Liu, Q; Guo, G; Huo, W J; Pei, C X; Zhang, S L; Wang, H

2018-05-01

This study evaluated the effects of dietary concentrate levels and 2-methylbutyrate (2MB) supplementation on performance, ruminal fermentation, bacteria abundance, microbial enzyme activity and urinary excretion of purine derivatives (PD) in steers. Eight ruminally cannulated Simmental steers (12 months of age; 389 ± 3.7 kg of body weight) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement. Moderate-concentrate (400 g/kg diet [MC]) or high-concentrate (600 g/kg diet [HC]) diets were fed with or without 2MB (0 g/day [2MB-] or 15.0 g/day [2MB+]). Dry matter intake and average daily gain increased, but feed conversion ratio decreased with the HC diet or 2MB supplementation. Ruminal pH decreased, but total volatile fatty acid increased with the HC diet or 2MB supplementation. Molar proportion of acetate and acetate-to-propionate ratio decreased with the HC diet, but increased with 2MB supplementation. Propionate molar proportion and ruminal NH 3 -N content increased with the HC diet, but decreased with 2MB supplementation. Neutral detergent fibre degradability decreased with the HC diet, but increased with 2MB supplementation. Crude protein degradability increased with the HC diet or 2MB supplementation. Abundance of Ruminococcus albus, Ruminococcus flavefaciens, Fibrobacter succinogenes and Bufyrivibrio fibrisolvens as well as activities of carboxymethyl cellulase, cellobiase, xylanase and pectinase decreased with the HC diet, but increased with 2MB supplementation. However, abundance of Prevotella ruminicola and Ruminobacter amylophilus as well as activities of α-amylase and protease increased with the HC diet or 2MB supplementation. Total PD excretion also increased with the HC diet or 2MB supplementation. The results suggested that growth performance, ruminal fermentation, CP degradability and total PD excretion increased with increasing dietary concentrate level from 40% to 60% or 2MB supplementation. The observed diet × 2MB interaction indicated that supplementation of 2MB was more efficacious for improving growth performance, ruminal fermentation and total PD excretion with promoted ruminal bacteria abundance and enzyme activity in the MC diet than in the HC diet. © 2018 Blackwell Verlag GmbH.

Utilization of nitrogen in cows consuming wet distillers grains with solubles in alfalfa and corn silage-based dairy rations.

PubMed

Gehman, A M; Kononoff, P J

2010-07-01

The objectives of this experiment were to determine the effects of forage type on nutrient digestibility, purine derivative excretion, nitrogen utilization, and milk production in dairy cattle consuming rations containing high levels of wet distillers grains with solubles (WDGS). Primiparous (n=8) and multiparous (n=20) Holstein cows were used in a replicated 4 x 4 Latin square. Animals were fed 1 of 4 treatments during each 21-d period: 1) CONT-CS, 0% WDGS and high corn silage; 2) CONT-AS, 0% WDGS and high alfalfa silage; 3) WDGS-CS, 25% WDGS and high corn silage; and 4) WDGS-AS, 25% WDGS and high alfalfa silage (dry matter basis). Intake and milk data were collected daily and averaged for d 15 to 21 of each period. Dry matter intake was lower for CONT-CS than for CONT-AS, WDGS-CS, and WDGS-AS (22.5, 24.6, 24.6, and 24.8 kg/d, respectively). Digestibility of dry matter, organic matter, neutral detergent fiber, and N were not affected by treatment, averaging 59.6, 62.3, 40.1, and 58.6%, respectively. Excretion of urinary purine derivatives was greatest for WDGS-AS, followed by WDGS-CS, and then CONT-CS and CONT-AS. Thus, by calculation, estimated microbial protein flow was highest for WDGS-AS (2,189.9 g/d) followed by WDGS-CS (1,996.2 g/d), CONT-AS (1,640.0 g/d), and CONT-CS (1,627.0 g/d). Mass of fecal N was not different among treatments (averaging 287.1+/-14.8 g/d), but urinary and manure N were reduced for rations with WDGS compared with those not including WDGS. Observed 4% fat-corrected milk was greatest for WDGS-AS, followed by WDGS-CS, and then CONT-CS and CONT-AS (30.7, 29.7, 28.3, and 27.2 kg/d, respectively). Milk protein yield was greatest for WDGS-AS (1.00 kg/d), followed by WDGS-CS, and then CONT-AS and CONT-CS (0.96, 0.91, 0.86 kg/d, respectively). This research demonstrated that rations can be balanced for dairy cattle to include up to 25% WDGS and result in increased microbial protein synthesis, milk production, and milk protein yield. Copyright (c) 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Structure-activity relationships and molecular studies of novel arylpiperazinylalkyl purine-2,4-diones and purine-2,4,8-triones with antidepressant and anxiolytic-like activity.

PubMed

Zagórska, Agnieszka; Kołaczkowski, Marcin; Bucki, Adam; Siwek, Agata; Kazek, Grzegorz; Satała, Grzegorz; Bojarski, Andrzej J; Partyka, Anna; Wesołowska, Anna; Pawłowski, Maciej

2015-06-05

A novel series of arylpiperazinylalkyl purine-2,4-diones (4-27) and purine-2,4,8-triones (31-38) was synthesized and tested to evaluated their affinity for the serotoninergic (5-HT1A, 5-HT6, 5-HT7) and dopaminergic (D2) receptors. Compounds with purine-2,4-dione nucleus generally had affinity values higher than the corresponding purine-2,4,8-trione compounds. A spectrum of receptor activities was observed for compounds with a substituent at the 7-position of the imidazo[2,1-f]purine-2,4-dione system and some potent 5-HT1A (18, 25), 5-HT7 (14) and mixed 5-HT1A/5-HT7 (8, 9) receptor ligands with additional affinity for dopamine D2 receptors (15) has been identified. Moreover, docking studies proved that a substituent at the 7-position of 1,3-dimethyl-(1H,8H)-imidazo[2,1-f]purine-2,4-dione could be essential for receptor affinity and selectivity, especially towards 5-HT1A and 5-HT7. The results of the preliminary pharmacological in vivo studies of selected derivatives of 1,3-dimethyl-(1H,8H)-imidazo[2,1-f]purine-2,4-dione, including 9 as a potential anxiolytic, 8 and 15 as potential antidepressants, and 18 and 25 as potential antidepressant and anxiolytic agents. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Prebiotic syntheses of purines and pyrimidines

NASA Technical Reports Server (NTRS)

Basile, B.; Oro, J.; Lazcano, A.

1984-01-01

The results of experimental and theoretical investigations of the prebiotic synthesis of purines and pyramidines are surveyed. Topics examined include the synthesis of purines from HCN via 4,5-disubstituted imidazole derivatives in aqueous solutions or liquid NH3, simultaneous formation of amino acids and purines by electron irradiation of CH4-NH3-H2O mixtures, synthesis of pyrimadines from cynoacetylene, energetics, formation of bases under anhydrous or concentrated conditions, formation of bases under dilute conditions, Fischer-Tropsch-type reactions, and the role of activated intermediates. It is pointed out that the precursor compounds have been detected in the interstellar medium, on Titan, and in other solar-system bodies, and that solar-nebula HCN concentrations of the order of 1-10 mM have been estimated on the basis of meteorite measurements.

Electronic and Structural Elements That Regulate the Excited-State Dynamics in Purine Nucleobase Derivatives

PubMed Central

2015-01-01

The excited-state dynamics of the purine free base and 9-methylpurine are investigated using experimental and theoretical methods. Femtosecond broadband transient absorption experiments reveal that excitation of these purine derivatives in aqueous solution at 266 nm results primarily in ultrafast conversion of the S2(ππ*) state to the vibrationally excited 1nπ* state. Following vibrational and conformational relaxation, the 1nπ* state acts as a doorway state in the efficient population of the triplet manifold with an intersystem crossing lifetime of hundreds of picoseconds. Experiments show an almost 2-fold increase in the intersystem crossing rate on going from polar aprotic to nonpolar solvents, suggesting that a solvent-dependent energy barrier must be surmounted to access the singlet-to-triplet crossing region. Ab initio static and surface-hopping dynamics simulations lend strong support to the proposed relaxation mechanism. Collectively, the experimental and computational results demonstrate that the accessibility of the nπ* states and the topology of the potential energy surfaces in the vicinity of conical intersections are key elements in controlling the excited-state dynamics of the purine derivatives. From a structural perspective, it is shown that the purine chromophore is not responsible for the ultrafast internal conversion in the adenine and guanine monomers. Instead, C6 functionalization plays an important role in regulating the rates of radiative and nonradiative relaxation. C6 functionalization inhibits access to the 1nπ* state while simultaneously facilitating access to the 1ππ*(La)/S0 conical intersection, such that population of the 1nπ* state cannot compete with the relaxation pathways to the ground state involving ring puckering at the C2 position. PMID:25763596

RECEPTOR AFFINITY AND PHOSPHODIESTERASES 4B AND 10A ACTIVITY OF OCTAHYDRO- AND 6,7-DIMETHOXY-3,4-DIHYDRO- ISOQUINOLIN-2(1H)-YL-ALKYL DERIVATIVES OF IMIDAZO- AND PYRIMIDINO[2,1-f]PURINES.

PubMed

Zagórska, Agnieszka; Gryzło, Beata; Satała, Grzegorz; Bojarski, Andrzej J; Głuch-Lutwin, Monika; Mordyl, Barbara; Kazek, Grzegorz; Pawłowski, Maciej

2016-01-01

A series of octahydro- and 6,7-dimethoxy-3,4-dihydro- isoquinolin-2(1H)-yl-alkyl derivatives of imidazo- and pyrimidino[2,1-f]purines were synthesized and biologically evaluated in in vitro competition binding experiments for serotonin 5-HT(1A), 5-HT(6), 5-HT(7), and dopamine D2 receptors and inhibitory potencies for phosphodiesterases - PDE4B1 and PDE10A. The structure-activity relationships allowed to determine the structural features responsible for receptor and enzyme activity. Compound 5 (8-(4-(6,7-dimethoxy-3,4-dihydroiso- quinolin-2(1H)butyl)1,3-dimethyl-H-imidazo[2,1-f]purine-2,4(3H,8H)-dione) could be regarded as promising structure for further modification and detailed mechanistic study for obtained hybrid ligands.

S-allyl derivatives of 6-mercaptopurine are highly potent drugs against human B-CLL through synergism between 6-mercaptopurine and allicin.

PubMed

Miron, Talia; Wilchek, Meir; Shvidel, Lev; Berrebi, Alain; Arditti, Fabian D

2012-12-01

S-allylthio-6-mercaptopurine and its ribose derivative were tested for anti-leukemic activity, using a human- mouse B-CLL model. The novel prodrugs contain two components, a purine analog, which interferes with DNA synthesis, and an S-allylthio, readily engaging in thiol-disulfide exchange reactions. The latter component targets the redox homeostasis which is more sensitive in leukemic cells, than in normal B-cells. Upon administration, the prodrug permeates cells, instantly reacts with free thiol, forming S-allyl mixed disulfides and releasing purine. Several cycles of thiol-disulfide exchange reactions occur, thus extending the duration of the prodrug effects. The concerted action of 2 components, as compared with purine alone, boosted in vitro apoptotis in B-CLL cells from 10% to 38%, and decreased in vivo engraftment of B-CLL from 30% to 0.7%. Copyright © 2012 Elsevier Ltd. All rights reserved.

Catabolism of exogenous deoxyinosine in cultured epithelial amniotic cells.

PubMed

Carta, M C; Mattana, A; Camici, M; Allegrini, S; Tozzi, M G; Sgarrella, F

2001-10-03

Uptake and catabolism of purine nucleosides have been commonly considered as means to salvage the purine ring for nucleic acid synthesis, usually neglecting the destiny of the pentose moiety. With the aim to ascertain if deoxyribose derived from exogenous DNA can be utilised as a carbon and energy source, we studied the catabolism of exogenous deoxyinosine in a cell line derived from human amnion epithelium (WISH). Intact WISH cells catabolise deoxyinosine by conversion into hypoxanthine. The nucleoside enters the cell through a nitrobenzylthioinosine-insensitive equilibrative transport. Deoxyinosine undergoes a phosphorolytic cleavage inside the cell. The purine base diffuses back to the external medium, while the phosphorylated pentose moiety can be further catabolised to glycolysis and citric acid cycle intermediates. Our results indicate that the catabolism of the deoxynucleoside can be considered mainly as a means to meet the carbon and energy requirements of growing cells.

Inner-shell chemical shift of DNA/RNA bases and inheritance from their parent purine and pyrimidine.

PubMed

Wang, Feng; Zhu, Quan; Ivanova, Elena

2008-11-01

Inner-shell electronic structures, properties and ionization spectra of DNA/RNA bases are studied with respect to their parent pyrimidine and purine species. Density functional theory B3LYP/aug-cc-pVTZ has been employed to produce the geometries of the bases, whereas LB94/et-pVQZ//B3LYP/aug-cc-pVTZ is used to calculate site-related Hirshfeld charges and core (vertical) ionization energies, as well as inner-shell spectra of C1s, N1s and O1s for DNA/RNA bases and their parent pyrimidine and purine species. The site-dependent variations of properties indicate the changes and inheritance of chemical environment when pyrimidine and purine become substituted. In general, although the changes are site-dependent, they are also ring-dependent. Pyrimidine bases change less significantly with respect to their parent pyrimidine than the purine bases with respect to their parent purine. Pyrimidine bases such as uracil, thymine and cytosine inherit certain properties from their parent pyrimidine, such as the Hirshfeld charge distributions and the order of core ionization energy level etc. No particular sites in the pyrimidine derivatives are engaged with a dramatic chemical shift nor with energy crossings to other sites. For the core shell spectra, the purine bases inherit very little from their parent purine, and guanine exhibits the least similarities to the parent among all the DNA/RNA bases.

Relationship between plasma uridine and urinary urea excretion.

PubMed

Ka, Tuneyoshi; Inokuchi, Taku; Tamada, Daisuke; Suda, Michio; Tsutsumi, Zenta; Okuda, Chihiro; Yamamoto, Asako; Takahashi, Sumio; Moriwaki, Yuji; Yamamoto, Tetsuya

2010-03-01

To investigate whether the concentration of uridine in plasma is related to the urinary excretion of urea, 45 healthy male subjects with normouricemia and normal blood pressure were studied after providing informed consent. Immediately after collection of 24-hour urine, blood samples were drawn after an overnight fast except for water. The contents of ingested foods during the 24-hour urine collection period were described by the subjects and analyzed by a dietician. Simple regression analysis showed that plasma uridine was correlated with the urinary excretions of urea (R = 0.41, P < .01), uric acid (R = 0.36, P < .05), and uridine (R = 0.30, P < .05), as well as uric acid clearance (R = 0.35, P < .05) and purine intake (R = 0.30, P < .05). In contrast, multiple regression analysis showed a positive relationship only between plasma uridine and urinary excretion of urea. These results suggest that an increase in de novo pyrimidine synthesis leads to an increased concentration of uridine in plasma via nitrogen catabolism in healthy subjects with normouricemia and normal blood pressure. (c) 2010 Elsevier Inc. All rights reserved.

Synthesis and biological evaluation of 2-fluoro and 3-trifluoromethyl-phenyl-piperazinylalkyl derivatives of 1H-imidazo[2,1-f]purine-2,4(3H,8H)-dione as potential antidepressant agents.

PubMed

Zagórska, Agnieszka; Bucki, Adam; Kołaczkowski, Marcin; Siwek, Agata; Głuch-Lutwin, Monika; Starowicz, Gabriela; Kazek, Grzegorz; Partyka, Anna; Wesołowska, Anna; Słoczyńska, Karolina; Pękala, Elżbieta; Pawłowski, Maciej

2016-01-01

A series of 2-fluoro and 3-trifluoromethylphenylpiperazinylalkyl derivatives of 1H-imidazo[2,1-f]purine-2,4(3H,8H)-dione (4-21) were synthesized and evaluated for their serotonin (5-HT 1A /5-HT 7 ) receptor affinity and phosphodiesterase (PDE4B and PDE10A) inhibitor activity. The study enabled the identification of potent 5-HT 1A , 5-HT 7 and mixed 5-HT 1A /5-HT 7 receptor ligands with weak inhibitory potencies for PDE4B and PDE10A. The tests have been completed with the determination of lipophilicity and metabolic stability using micellar electrokinetic chromatography (MEKC) system and human liver microsomes (HLM) model. In preliminary pharmacological in vivo studies, selected compound 8-(5-(4-(2-fluorophenyl)piperazin-1-yl)pentyl)-1,3,7-trimethyl-1H-imidazo[2,1-f]purine-2,4(3H,8H)-dione (9) behaved as a potential antidepressant in forced swim test (FST) in mice. Moreover, potency of antianxiety effects evoked by 9 (2.5 mg/kg) is greater than that of the reference anxiolytic drug, diazepam. Molecular modeling revealed that fluorinated arylpiperazinylalkyl derivatives of 1H-imidazo[2,1-f]purine-2,4(3H,8H)-dione have major significance for the provision of lead compounds for antidepressant and/or anxiolytic application.

Synthesis and pH-dependent stability of purine-6-sulfenic acid, a putative reactive metabolite of 6-thiopurine.

PubMed

Abraham, R T; Benson, L M; Jardine, I

1983-10-01

Previous studies have shown that 6-thiopurine is metabolically activated by hepatic cytochrome P-450 to an intermediate capable of binding to proteins by a mixed disulfide linkage. The identity of the active metabolite was postulated to be purine-6-sulfenic acid. In the present report, we describe the synthesis of the sulfenic acid derivatives of 6-thiopurine and two structurally similar compounds, 9-methyl-6-thiopurine and 4-mercapto-1H-pyrazolo[3,4-d]-pyrimidine. The unusual pH-dependent stability profiles of these compounds in buffered aqueous media are presented and explained on the basis of a disproportionation mechanism of sulfenic acid decomposition. Studies with radiolabeled purine-6-sulfenic acid demonstrate that this species binds directly to hepatic microsomal protein. These results support the proposed involvement of purine-6-sulfenic acid in the metabolic activation and tissue binding of 6-thiopurine.

AMPD2 Regulates GTP Synthesis and is Mutated in a Potentially-Treatable Neurodegenerative Brainstem Disorder

PubMed Central

Akizu, Naiara; Cantagrel, Vincent; Schroth, Jana; Cai, Na; Vaux, Keith; McCloskey, Douglas; Naviaux, Robert K.; Vleet, Jeremy Van; Fenstermaker, Ali G.; Silhavy, Jennifer L.; Scheliga, Judith S.; Toyama, Keiko; Morisaki, Hiroko; Sonmez, Fatma Mujgan; Celep, Figen; Oraby, Azza; Zaki, Maha S.; Al-Baradie, Raidah; Faqeih, Eissa; Saleh, Mohammad; Spencer, Emily; Rosti, Rasim Ozgur; Scott, Eric; Nickerson, Elizabeth; Gabriel, Stacey; Morisaki, Takayuki; Holmes, Edward W.; Gleeson, Joseph G.

2013-01-01

Purine biosynthesis and metabolism, conserved in all living organisms, is essential for cellular energy homeostasis and nucleic acids synthesis. The de novo synthesis of purine precursors is under tight negative feedback regulation mediated by adenosine and guanine nucleotides. We describe a new distinct early-onset neurodegenerative condition resulting from mutations in the adenosine monophosphate deaminase 2 gene (AMPD2). Patients have characteristic brain imaging features of pontocerebellar hypoplasia (PCH), due to loss of brainstem and cerebellar parenchyma. We found that AMPD2 plays an evolutionary conserved role in the maintenance of cellular guanine nucleotide pools by regulating the feedback inhibition of adenosine derivatives on de novo purine synthesis. AMPD2 deficiency results in defective GTP-dependent initiation of protein translation, which can be rescued by administration of purine precursors. These data suggest AMPD2-related PCH as a new, potentially treatable early-onset neurodegenerative disease. PMID:23911318

AMPD2 regulates GTP synthesis and is mutated in a potentially treatable neurodegenerative brainstem disorder.

PubMed

Akizu, Naiara; Cantagrel, Vincent; Schroth, Jana; Cai, Na; Vaux, Keith; McCloskey, Douglas; Naviaux, Robert K; Van Vleet, Jeremy; Fenstermaker, Ali G; Silhavy, Jennifer L; Scheliga, Judith S; Toyama, Keiko; Morisaki, Hiroko; Sonmez, Fatma M; Celep, Figen; Oraby, Azza; Zaki, Maha S; Al-Baradie, Raidah; Faqeih, Eissa A; Saleh, Mohammed A M; Spencer, Emily; Rosti, Rasim Ozgur; Scott, Eric; Nickerson, Elizabeth; Gabriel, Stacey; Morisaki, Takayuki; Holmes, Edward W; Gleeson, Joseph G

2013-08-01

Purine biosynthesis and metabolism, conserved in all living organisms, is essential for cellular energy homeostasis and nucleic acid synthesis. The de novo synthesis of purine precursors is under tight negative feedback regulation mediated by adenosine and guanine nucleotides. We describe a distinct early-onset neurodegenerative condition resulting from mutations in the adenosine monophosphate deaminase 2 gene (AMPD2). Patients have characteristic brain imaging features of pontocerebellar hypoplasia (PCH) due to loss of brainstem and cerebellar parenchyma. We found that AMPD2 plays an evolutionary conserved role in the maintenance of cellular guanine nucleotide pools by regulating the feedback inhibition of adenosine derivatives on de novo purine synthesis. AMPD2 deficiency results in defective GTP-dependent initiation of protein translation, which can be rescued by administration of purine precursors. These data suggest AMPD2-related PCH as a potentially treatable early-onset neurodegenerative disease. Copyright © 2013 Elsevier Inc. All rights reserved.

Structure-5-HT/D2 Receptor Affinity Relationship in a New Group of 1-Arylpiperazynylalkyl Derivatives of 8-Dialkylamino-3,7-dimethyl-1H-purine-2,6(3H,7H)-dione.

PubMed

Żmudzki, Paweł; Satała, Grzegorz; Chłoń-Rzepa, Grażyna; Bojarski, Andrzej J; Kazek, Grzegorz; Siwek, Agata; Gryboś, Anna; Głuch-Lutwin, Monika; Wesołowska, Anna; Pawłowski, Maciej

2016-10-01

In our previous papers, we have reported that some 8-amino-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione derivatives possessed high affinity and displayed agonistic, partial agonistic, or antagonistic activity for serotonin 5-HT 1A and dopamine D 2 receptors. In order to examine further the influence of the substituent in the position 8 of the purine moiety and the influence of the xanthine core on the affinity for serotonin 5-HT 1A , 5-HT 2A , 5-HT 6 , 5-HT 7 , and dopamine D 2 receptors, two series of 1-arylpiperazynylalkyl derivatives of 8-amino-3,7-dimethyl-1H-purine-2,6(3H,7H)-dione were synthesized. All the final compounds were investigated in in vitro competition binding experiments for the serotonin 5-HT 1A , 5-HT 2A , 5-HT 6 , 5-HT 7 , and dopamine D 2 receptors. The structure-affinity relationships for this group of compounds were discussed. For selected compounds, the functional assays for the 5-HT 1A and D 2 receptors were carried out. The results of the assays indicated that these groups of derivatives possessed antagonistic activity for 5-HT 1A receptors and agonistic, partial agonistic, or antagonistic activity for D 2 receptors. In total, 26 new compounds were synthesized, 20 of which were tested in in vitro binding experiments and 5 were tested in in vitro functional assays. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of carbon-11-labeled imidazopyridine- and purine-thioacetamide derivatives as new potential PET tracers for imaging of nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1).

PubMed

Gao, Mingzhang; Wang, Min; Zheng, Qi-Huang

2016-03-01

The target tracer carbon-11-labeled imidazopyridine- and purine-thioacetamide derivatives, N-(3-[(11)C]methoxy-4-methoxyphenyl)-2-((5-methoxy-3H-imidazo[4,5-b]pyridin-2-yl)thio)acetamide (3-[(11)C]4a) and N-(4-[(11)C]methoxy-3-methoxyphenyl)-2-((5-methoxy-3H-imidazo[4,5-b]pyridin-2-yl)thio)acetamide (4-[(11)C]4a); 2-((6-amino-9H-purin-8-yl)thio)-N-(3-[(11)C]methoxy-4-methoxyphenyl)acetamide (3-[(11)C]8a) and 2-((6-amino-9H-purin-8-yl)thio)-N-(4-[(11)C]methoxy-3-methoxyphenyl)acetamide (4-[(11)C]8a), were prepared by O-[(11)C]methylation of their corresponding precursors with [(11)C]CH3OTf under basic condition (2N NaOH) and isolated by a simplified solid-phase extraction (SPE) method in 50-60% radiochemical yields based on [(11)C]CO2 and decay corrected to end of bombardment (EOB). The overall synthesis time from EOB was 23min, the radiochemical purity was >99%, and the specific activity at end of synthesis (EOS) was 185-555GBq/μmol. Copyright © 2016 Elsevier Ltd. All rights reserved.

Three stages during the evolution of the genetic code. [Abstract only

NASA Technical Reports Server (NTRS)

Baumann, U.; Oro, J.

1994-01-01

A diversification of the genetic code based on the number of codons available for the proteinous amino acids is established. Three groups of amino acids during evolution of the code are distinguished. On the basis of their chemical complexity and a small codon number those amino acids emerging later in a translation process are derived. Both criteria indicate that His, Phe, Tyr, Cys and either Lys or Asn were introduced in the second stage, whereas the number of codons alone gives evidence that Trp and Met were introduced in the third stage. The amino acids of stage one use purines rich codons, thus purines have been retained in their third codon position. All the amino acids introduced in the second stage, in contrast, use pyrimidines in this codon position. A low abundance of pyrimidines during early translation is derived. This assumption is supported by experiments on non enzymatic replication and interactions of DNA hairpin loops with a complementary strand. A back extrapolation concludes a high purine content of the first nucleic acids which gradually decreased during their evolution. Amino acids independently available form prebiotic synthesis were thus correlated to purine rich codons. Conclusions on prebiotic replication are discussed also in the light of recent codon usage data.

Effect of protein level and urea in concentrate mixture on feed intake and rumen fermentation in swamp buffaloes fed rice straw-based diet.

PubMed

Kang, Sungchhang; Wanapat, Metha; Phesatcha, Kampanat; Norrapoke, Thitima

2015-04-01

Four rumen-fistulated Thai native swamp buffaloes were randomly assigned according to a 2 × 2 factorial arrangement in a 4 × 4 Latin square design to assess the effect of protein (CP) level and urea (U) source in concentrate diet on feed utilization and rumen ecology. The treatments were as follows: concentrate containing CP at 120 g/kg (soybean meal, SBM) (T1), 160 g/kg (SBM) (T2), 120 g/kg (U) (T3), and 160 g/kg (U) (T4), respectively. All buffaloes were fed concentrate at 10 g/kg of body weight, and rice straw was offered ad libitum. Feed intake and digestibilities of CP, neutral detergent fiber, and acid detergent fiber increased (P < 0.05) in treatments with higher level of CP especially with U source (P < 0.05). In contrast, CP level and source in concentrate did not affect on ruminal pH and temperature (P > 0.05), while concentration of ruminal ammonia (N), blood urea (U), volatile fatty acids profile, microorganism populations, and variable bacterial growth increased in buffaloes consumed concentrate containing CP at 160 g/kg (T2 and T4; P < 0.05). Fecal and urinary N excretions decreased in buffaloes consumed concentrate containing higher CP level especially with U source while purine derivatives increased which resulted in a higher N balance as compared to lower CP level and SBM source treatments (P < 0.05). In summary, higher CP level in concentrate improved feed intake, nutrient digestibility, purine derivatives, and rumen ecology, and U had shown better result than SBM. Concentrate mixtures containing 16 g/kg CP with U 40 g/kg could improved nutrients utilization with no adverse effects for swamp buffaloes fed on rice straw.

Hereditary xanthinuria and urolithiasis in a domestic shorthair cat

PubMed Central

Furman, E.; Hooijberg, E.H.; Leidinger, E.; Zedinger, C.; Giger, U.; Leidinger, J.

2015-01-01

A 2-year-old domestic shorthair cat was presented with a history of hematuria, stranguria and intermittent urethral obstruction. Urine sediment showed hematuria, pyuria, and yellow-brown, amorphous and spherical crystals. Upon surgical correction of the obstructed urethra by perineal urethrostomy, many dark yellow to grey, irregular, gravel-like to millet grain-sized uroliths, consisting of 100% xanthine by crystallography were found. The urinary xanthine concentration was high. The cat subsequently developed bilateral nephroliths, recurrent urinary tract infection, and chronic kidney failure. Dietary management with a low-purine diet failed in part due to poor compliance, and the cat was euthanized at 6 years of age. Xanthinuria is rare inborn error of metabolism in cats and other species but should be considered as a differential diagnosis in cases of feline urolithiasis. No associated molecular genetic defect has been elucidated, and management of these cases is difficult. In the absence of calculi for analysis, measuring urinary xanthine concentration can help in diagnosing this metabolic defect. PMID:26478726

Three-dimensional structure of E. Coli purine nucleoside phosphorylase at 0.99 Å resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Timofeev, V. I., E-mail: tostars@mail.ru; Abramchik, Yu. A., E-mail: ugama@yandex.ru; Zhukhlistova, N. E., E-mail: inna@ns.crys.ras.ru

2016-03-15

Purine nucleoside phosphorylases (PNPs) catalyze the reversible phosphorolysis of nucleosides and are key enzymes involved in nucleotide metabolism. They are essential for normal cell function and can catalyze the transglycosylation. Crystals of E. coli PNP were grown in microgravity by the capillary counterdiffusion method through a gel layer. The three-dimensional structure of the enzyme was determined by the molecular-replacement method at 0.99 Å resolution. The structural features are considered, and the structure of E. coli PNP is compared with the structures of the free enzyme and its complexes with purine base derivatives established earlier. A comparison of the environment ofmore » the purine base in the complex of PNP with formycin A and of the pyrimidine base in the complex of uridine phosphorylase with thymidine revealed the main structural features of the base-binding sites. Coordinates of the atomic model determined with high accuracy were deposited in the Protein Data Bank (PDB-ID: 4RJ2).« less

Should Metabolic Diseases Be Systematically Screened in Nonsyndromic Autism Spectrum Disorders?

PubMed Central

Schiff, Manuel; Benoist, Jean-François; Aïssaoui, Sofiane; Boepsflug-Tanguy, Odile; Mouren, Marie-Christine; de Baulny, Hélène Ogier; Delorme, Richard

2011-01-01

Background In the investigation of autism spectrum disorders (ASD), a genetic cause is found in approximately 10–20%. Among these cases, the prevalence of the rare inherited metabolic disorders (IMD) is unknown and poorly evaluated. An IMD responsible for ASD is usually identified by the associated clinical phenotype such as dysmorphic features, ataxia, microcephaly, epilepsy, and severe intellectual disability (ID). In rare cases, however, ASD may be considered as nonsyndromic at the onset of a related IMD. Objectives To evaluate the utility of routine metabolic investigations in nonsyndromic ASD. Patients and Methods We retrospectively analyzed the results of a metabolic workup (urinary mucopolysaccharides, urinary purines and pyrimidines, urinary creatine and guanidinoacetate, urinary organic acids, plasma and urinary amino acids) routinely performed in 274 nonsyndromic ASD children. Results The metabolic parameters were in the normal range for all but 2 patients: one with unspecific creatine urinary excretion and the other with persistent 3-methylglutaconic aciduria. Conclusions These data provide the largest ever reported cohort of ASD patients for whom a systematic metabolic workup has been performed; they suggest that such a routine metabolic screening does not contribute to the causative diagnosis of nonsyndromic ASD. They also emphasize that the prevalence of screened IMD in nonsyndromic ASD is probably not higher than in the general population (<0.5%). A careful clinical evaluation is probably more reasonable and of better medical practice than a costly systematic workup. PMID:21760924

Diet effects on urine composition of cattle and N2O emissions.

PubMed

Dijkstra, J; Oenema, O; van Groenigen, J W; Spek, J W; van Vuuren, A M; Bannink, A

2013-06-01

Ruminant production contributes to emissions of nitrogen (N) to the environment, principally ammonia (NH3), nitrous oxide (N2O) and di-nitrogen (N2) to air, nitrate (NO3 -) to groundwater and particulate N to surface waters. Variation in dietary N intake will particularly affect excretion of urinary N, which is much more vulnerable to losses than is faecal N. Our objective is to review dietary effects on the level and form of N excreted in cattle urine, as well as its consequences for emissions of N2O. The quantity of N excreted in urine varies widely. Urinary N excretion, in particular that of urea N, is decreased upon reduction of dietary N intake or an increase in the supply of energy to the rumen microorganisms and to the host animal itself. Most of the N in urine (from 50% to well over 90%) is present in the form of urea. Other nitrogenous components include purine derivatives (PD), hippuric acid, creatine and creatinine. Excretion of PD is related to rumen microbial protein synthesis, and that of hippuric acid to dietary concentration of degradable phenolic acids. The N concentration of cattle urine ranges from 3 to 20 g/l. High-dietary mineral levels increase urine volume and lead to reduced urinary N concentration as well as reduced urea concentration in plasma and milk. In lactating dairy cattle, variation in urine volume affects the relationship between milk urea and urinary N excretion, which hampers the use of milk urea as an accurate indicator of urinary N excretion. Following its deposition in pastures or in animal houses, ubiquitous microorganisms in soil and waters transform urinary N components into ammonium (NH4 +), and thereafter into NO3 - and ultimately in N2 accompanied with the release of N2O. Urinary hippuric acid, creatine and creatinine decompose more slowly than urea. Hippuric acid may act as a natural inhibitor of N2O emissions, but inhibition conditions have not been defined properly yet. Environmental and soil conditions at the site of urine deposition or manure application strongly influence N2O release. Major dietary strategies to mitigating N2O emission from cattle operations include reducing dietary N content or increasing energy content, and increasing dietary mineral content to increase urine volume. For further reduction of N2O emission, an integrated animal nutrition and excreta management approach is required.

Effect of ethanol on metabolism of purine bases (hypoxanthine, xanthine, and uric acid).

PubMed

Yamamoto, Tetsuya; Moriwaki, Yuji; Takahashi, Sumio

2005-06-01

There are many factors that contribute to hyperuricemia, including obesity, insulin resistance, alcohol consumption, diuretic use, hypertension, renal insufficiency, genetic makeup, etc. Of these, alcohol (ethanol) is the most important. Ethanol enhances adenine nucleotide degradation and increases lactic acid level in blood, leading to hyperuricemia. In beer, purines also contribute to an increase in plasma uric acid. Although rare, dehydration and ketoacidosis (due to ethanol ingestion) are associated with the ethanol-induced increase in serum uric acid levels. Ethanol also increases the plasma concentrations and urinary excretion of hypoxanthine and xanthine via the acceleration of adenine nucleotide degradation and a possible weak inhibition of xanthine dehydrogenase activity. Since many factors such as the ALDH2*1 gene and ADH2*2 gene, daily drinking habits, exercise, and dehydration enhance the increase in plasma concentration of uric acid induced by ethanol, it is important to pay attention to these factors, as well as ingested ethanol volume, type of alcoholic beverage, and the administration of anti-hyperuricemic agents, to prevent and treat ethanol-induced hyperuricemia.

Three stages in the evolution of the genetic code

NASA Technical Reports Server (NTRS)

Baumann, U.; Oro, J.

1993-01-01

A diversification of the genetic code based on the number of codons available for the proteinous amino acids is established. Three groups of amino acids during evolution of the code are distinguished. On the basis of their chemical complexity those amino acids emerging later in a translation process are derived. Codon number and chemical complexity indicate that His, Phe, Tyr, Cys and either Lys or Asn were introduced in the second stage, whereas the number of codons alone gives evidence that Trp and Met were introduced in the third stage. The amino acids of stage 1 use purine-rich codons, while all the amino acids introduced in the second stage, in contrast, use pyrimidines in the third position of their codons. A low abundance of pyrimidines during early translation is derived. This assumption is supported by experiments on non-enzymatic replication and interactions of hairpin loops with a complementary strand. A back extrapolation concludes a high purine content of the first nucleic acids, which gradually decreased during their evolution. Amino acids independently available from prebiotic synthesis were thus correlated to purine-rich codons. Implications on the prebiotic replication are discussed also in the light of recent codon usage data.

Anti-proliferative activity of 2,6-dichloro-9- or 7-(ethoxycarbonylmethyl)-9H- or 7H-purines against several human solid tumour cell lines.

PubMed

Morales, Fátima; Ramírez, Alberto; Conejo-García, Ana; Morata, Cynthia; Marchal, Juan A; Campos, Joaquín M

2014-04-09

As leads we took several benzo-fused seven- and six-membered scaffolds linked to the pyrimidine or purine moieties with notable anti-proliferative activity against human breast, colon and melanoma cancerous cell lines. We then decided to maintain the double-ringed nitrogenous bases and change the other components to the ethyl acetate moiety. This way six purine and two 5-fluorouracil derivatives were obtained and evaluated against the MCF-7, HCT-116, A-375 and G-361 cancer cell lines. Two QSARs are obtained between the anti-proliferative IC₅₀ values for compounds 26-33 and the clog P against the melanoma cell lines A-375 and G-361. Our results show that two of the analogues [ethyl 2-(2,6-dichloro-9H- or 7H-purine-9- or 7-yl)acetates (30 and 33, respectively)] are potent cytotoxic agents against all the tumour cell lines assayed, showing single-digit micromolar IC₅₀ values. This exemplifies the potential of our previously reported purine compounds to qualify as lead structures for medicinal chemistry campaigns, affording simplified analogues easy to synthesize and with a noteworthy bioactivity. The selective activity of 30 and 33 against the melanoma cell line A-375, via apoptosis, supposes a great advantage for a future therapeutic use. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

The rate and pattern of urea infusion into the rumen of wethers alters nitrogen balance and plasma ammonia.

PubMed

Recavarren, M I; Milano, G D

2014-12-01

Changes in N balance, urinary excretion of purine derivative (PD), urea, creatinine and ammonia and plasma ammonia, glucose, urea, insulin and IGF-1 were examined in four wethers (37 ± 2.6 kg BW). The animals were fitted with permanent ruminal catheters, fed lucerne hay (9.4 MJ/day; 23 g N/day; 7 g soluble N/day, 6 equal meals/day) and treated with contrasting rates of urea infusion into the rumen: first, a continuous infusion (CT), at 3.2 mg urea-N/min for 10 days and then a discontinuous infusion (DT) at 156 mg urea-N/min for 4 min; in 6 daily doses with the meals for 7 days. N balance was calculated from pooled samples of faeces and urine. Jugular blood samples were collected before and 1.5 h after the morning meal (M1) on days CT10, DT2, DT4 and DT6. N retention decreased during DT (p = 0.01) due to a significant increase of N excretion in urine (4 g/day; p = 0.009) and faeces (1 g/day; p = 0.02). Dry matter (p < 0.001) and N digestibility in vivo (p = 0.01) decreased significantly during DT. Urinary urea and PD excretion were not altered by treatment. Significant linear (p = 0.004) and quadratic (p = 0.001) effects were observed for plasma ammonia in M1 (from 170 CT10 to 235 μm DT2 and returned to 120 μm DT6). No changes were observed in plasma glucose, urea, insulin and IGF-1. Results indicate that changes from CT to DT reduced N retention in sheep due to enhanced urinary N excretion, but it was not associated with changes in urinary urea or PD excretion; or plasma concentrations of insulin and IGF-1. As the dry matter (DM) an N digestibility could account a 0.23 of the decrease in N retention; the largest fraction of the reduction in N retention remained unexplained by the results. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

Ethenoguanines Undergo Glycosylation by Nucleoside 2′-Deoxyribosyltransferases at Non-Natural Sites

PubMed Central

Ye, Wenjie; Paul, Debamita; Gao, Lina; Seckute, Jolita; Jayaraj, Karupiah; Zhang, Zhenfa; Kaminski, P. Alexandre

2014-01-01

Deoxyribosyl transferases and functionally related purine nucleoside phosphorylases are used extensively for synthesis of non-natural deoxynucleosides as pharmaceuticals or standards for characterizing and quantitating DNA adducts. Hence exploring the conformational tolerance of the active sites of these enzymes is of considerable practical interest. We have determined the crystal structure at 2.1 Å resolution of Lactobacillus helveticus purine deoxyribosyl transferase (PDT) with the tricyclic purine 8,9-dihydro-9-oxoimidazo[2,1-b]purine (N 2,3-ethenoguanine) at the active site. The active site electron density map was compatible with four orientations, two consistent with sites for deoxyribosylation and two appearing to be unproductive. In accord with the crystal structure, Lactobacillus helveticus PDT glycosylates the 8,9-dihydro-9-oxoimidazo[2,1-b]purine at N7 and N1, with a marked preference for N7. The activity of Lactobacillus helveticus PDT was compared with that of the nucleoside 2′-deoxyribosyltransferase enzymes (DRT Type II) from Lactobacillus leichmannii and Lactobacillus fermentum, which were somewhat more effective in the deoxyribosylation than Lactobacillus helveticus PDT, glycosylating the substrate with product profiles dependent on the pH of the incubation. The purine nucleoside phosphorylase of Escherichia coli, also commonly used in ribosylation of non-natural bases, was an order of magnitude less efficient than the transferase enzymes. Modeling based on published active-site structures as templates suggests that in all cases, an active site Phe is critical in orienting the molecular plane of the purine derivative. Adventitious hydrogen bonding with additional active site residues appears to result in presentation of multiple nucleophilic sites on the periphery of the acceptor base for ribosylation to give a distribution of nucleosides. Chemical glycosylation of O 9-benzylated 8,9-dihydro-9-oxoimidazo[2,1-b]purine also resulted in N7 and N1 ribosylation. Absent from the enzymatic and chemical glycosylations is the natural pattern of N3 ribosylation, verified by comparison of spectroscopic and chromatographic properties with an authentic standard synthesized by an unambiguous route. PMID:25521390

Metabolic Reprogramming During Purine Stress in the Protozoan Pathogen Leishmania donovani

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Jessica L.; Yates, Phillip A.; Soysa, Radika

The ability of Leishmania to survive in their insect or mammalian host is dependent upon an ability to sense and adapt to changes in the microenvironment. However, little is known about the molecular mechanisms underlying the parasite response to environmental changes, such as nutrient availability. To elucidate nutrient stress response pathways in Leishmania donovani, we have used purine starvation as the paradigm. The salvage of purines from the host milieu is obligatory for parasite replication; nevertheless, purine-starved parasites can persist in culture without supplementary purine for over 3 months, indicating that the response to purine starvation is robust and engendersmore » parasite survival under conditions of extreme scarcity. To understand metabolic reprogramming during purine starvation we have employed global approaches. Whole proteome comparisons between purine-starved and purine-replete parasites over a 6-48 h span have revealed a temporal and coordinated response to purine starvation. Purine transporters and enzymes involved in acquisition at the cell surface are upregulated within a few hours of purine removal from the media, while other key purine salvage components are upregulated later in the time-course and more modestly. After 48 h, the proteome of purine-starved parasites is extensively remodeled and adaptations to purine stress appear tailored to deal with both purine deprivation and general stress. To probe the molecular mechanisms affecting proteome remodeling in response to purine starvation, comparative RNA-seq analyses, qRT-PCR, and luciferase reporter assays were performed on purine-starved versus purine-replete parasites. While the regulation of a minority of proteins tracked with changes at the mRNA level, for many regulated proteins it appears that proteome remodeling during purine stress occurs primarily via translational and/or post-translational mechanisms.« less

Synthesis and antiproliferative activity of 6-phenylaminopurines.

PubMed

Canela, María-Dolores; Liekens, Sandra; Camarasa, María-José; Priego, Eva María; Pérez-Pérez, María-Jesús

2014-11-24

A series of novel 6-phenylaminopurines have been efficiently synthesized in 3 steps exploring different groups at positions 2, 8 and 9 of the purine ring and at the exocyclic nitrogen atom at position 6. Among the newly described purines, five compounds showed antiproliferative activity with IC50 values below 10 μM, the tetrahydroquinoline derivative at position 6 of phenylaminopurine being the most active of the series in the six cell lines tested. Moreover, the compounds induced G2/M phase arrest in human cervical carcinoma HeLa cells as reported for tubulin depolymerizing agents. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Catalytic Role of Manganese Oxides in Prebiotic Nucleobases Synthesis from Formamide.

PubMed

Bhushan, Brij; Nayak, Arunima; Kamaluddin

2016-06-01

Origin of life processes might have begun with the formation of important biomonomers, such as amino acids and nucleotides, from simple molecules present in the prebiotic environment and their subsequent condensation to biopolymers. While studying the prebiotic synthesis of naturally occurring purine and pyrimidine derivatives from formamide, the manganese oxides demonstrated not only good binding for formamide but demonstrated novel catalytic activity. A novel one pot manganese oxide catalyzed synthesis of pyrimidine nucleobases like thymine is reported along with the formation of other nucleobases like purine, 9-(hydroxyacetyl) purine, cytosine, 4(3 H)-pyrimidinone and adenine in acceptable amounts. The work reported is significant in the sense that the synthesis of thymine has exhibited difficulties especially under one pot conditions and also such has been reported only under the catalytic activity of TiO2. The lower oxides of manganese were reported to show higher potential as catalysts and their existence were favored by the reducing atmospheric conditions prevalent on early Earth; thereby confirming the hypothesis that mineral having metals in reduced form might have been more active during the course of chemical evolution. Our results further confirm the role of formamide as a probable precursor for the formation of purine and pyrimidine bases during the course of chemical evolution and origin of life.

Synthesis of aromatic cytokinins for plant biotechnology.

PubMed

Plíhalová, Lucie; Vylíčilová, Hana; Doležal, Karel; Zahajská, Lenka; Zatloukal, Marek; Strnad, Miroslav

2016-09-25

Cytokinins represent an important group of plant growth regulators that can modulate several biotechnological processes owing to their ability to influence almost all stages of plant development and growth. In addition, the use of purine based cytokinins with aromatic substituent in C6 position of the purine moiety in tissue culture techniques is currently experiencing a surge in interest, made possible by the ongoing systematic synthesis and study of these compounds. This review article outlines progress in the synthesis of aromatic cytokinins, the in vitro and in vivo effects of these substances and insights gleaned from their synthesis. As the purine moiety in these compounds can be substituted at several positions, we examine each of the substitution possibilities in relation to the derivatives prepared so far. The discussion highlights the gradual simplification of their preparation in relation to their application in practice and summarizes the relevant organic chemistry literature and published patents. Copyright © 2015 Elsevier B.V. All rights reserved.

Improved Model for Predicting the Free Energy Contribution of Dinucleotide Bulges to RNA Duplex Stability.

PubMed

Tomcho, Jeremy C; Tillman, Magdalena R; Znosko, Brent M

2015-09-01

Predicting the secondary structure of RNA is an intermediate in predicting RNA three-dimensional structure. Commonly, determining RNA secondary structure from sequence uses free energy minimization and nearest neighbor parameters. Current algorithms utilize a sequence-independent model to predict free energy contributions of dinucleotide bulges. To determine if a sequence-dependent model would be more accurate, short RNA duplexes containing dinucleotide bulges with different sequences and nearest neighbor combinations were optically melted to derive thermodynamic parameters. These data suggested energy contributions of dinucleotide bulges were sequence-dependent, and a sequence-dependent model was derived. This model assigns free energy penalties based on the identity of nucleotides in the bulge (3.06 kcal/mol for two purines, 2.93 kcal/mol for two pyrimidines, 2.71 kcal/mol for 5'-purine-pyrimidine-3', and 2.41 kcal/mol for 5'-pyrimidine-purine-3'). The predictive model also includes a 0.45 kcal/mol penalty for an A-U pair adjacent to the bulge and a -0.28 kcal/mol bonus for a G-U pair adjacent to the bulge. The new sequence-dependent model results in predicted values within, on average, 0.17 kcal/mol of experimental values, a significant improvement over the sequence-independent model. This model and new experimental values can be incorporated into algorithms that predict RNA stability and secondary structure from sequence.

Study of Copper and Purine-Copper Complexes on Modified Carbon Electrodes by Cyclic and Elimination Voltammetry

PubMed Central

Trnkova, Libuse; Zerzankova, Lenka; Dycka, Filip; Mikelova, Radka; Jelen, Frantisek

2008-01-01

Using a paraffin impregnated graphite electrode (PIGE) and mercury-modified pyrolytic graphite electrode with basal orientation (Hg-PGEb) copper(II) and Cu(II)-DNA purine base solutions have been studied by cyclic (CV) and linear sweep voltammetry (LSV) in connection with elimination voltammetry with linear scan (EVLS). In chloride and bromide solutions (pH 6), the redox process of Cu(II) proceeded on PIGE with two cathodic and two anodic potentially separated signals. According to the elimination function E4, the first cathodic peak corresponds to the reduction Cu(II) + e- → Cu(I) with the possibility of fast disproportionation 2Cu(I) → Cu(II)+ Cu(0). The E4 of the second cathodic peak signalized an electrode process controlled by a surface reaction. The electrode system of Cu(II) on Hg-PGEb in borate buffer (pH 9.2) was characterized by one cathodic and one anodic peak. Anodic stripping voltammetry (ASV) on PIGE and cathodic stripping voltammetry (CSV) on Hg-PGEb were carried out at potentials where the reduction of copper ions took place and Cu(I)-purine complexes were formed. By using ASV and CSV in combination with EVLS, the sensitivity of Cu(I)-purine complex detection was enhanced relative to either ASV or CSV alone, resulting in higher peak currents of more than one order of magnitude. The statistical treatment of CE data was used to determine the reproducibility of measurements. Our results show that EVLS in connection with the stripping procedure is useful for both qualitative and quantitative microanalysis of purine derivatives and can also reveal details of studied electrode processes. PMID:27879715

New 7-arylpiperazinylalkyl-8-morpholin-4-yl-purine-2,6-dione derivatives with anxiolytic activity - Synthesis, crystal structure and structure-activity study

NASA Astrophysics Data System (ADS)

Chłoń-Rzepa, Grażyna; Żmudzki, Paweł; Pawłowski, Maciej; Wesołowska, Anna; Satała, Grzegorz; Bojarski, Andrzej J.; Jabłoński, Mateusz; Kalinowska-Tłuścik, Justyna

2014-06-01

On the basis of our earlier studies with serotonin (5-HT) receptor ligands in the group of long-chain arylpiperazines (LCAPs), a new series of 7-arylpiperazinylalkyl-8-morpholin-4-yl-purine-2,6-dione derivatives (5-12) has been designed, synthesised and studied in vitro for their affinity for 5-HT1A, 5-HT2A, 5-HT6 and 5-HT7 receptors. The introduction of o-OCH3 and m-Cl into the phenylpiperazinyl moiety as well as the elongation of the linker between purine-2,6-dione core and arylpiperazine fragment modified the affinity for the tested 5-HT receptors. The structures of compounds 9-11 (hydrochloride salts) were confirmed by an X-ray diffraction method. All molecules adopted a different conformation in the crystal. The strongest observed type of interaction is a charge assisted hydrogen bond N+-H⋯Cl-. Additionally, the π-π interactions between 1,3-dimethyl-3,7-dihydropurine-2,6-dione cores of the neighbouring molecules were also observed. As it is observed in the presented crystal structures, the morpholine ring (a potential donor and acceptor of the hydrogen bonds) seems to be an attractive substituent, that may support binding to the non-specific sites of 5-HT receptors. Another interesting feature is the mutual orientation of rings in the arylpiperazine fragment, with plausible influence on ligand-receptor recognition. For compound 10, with strong 5-HT1A binding affinity, the mutual orientation of rings is determined by the intramolecular weak C-H⋯O hydrogen bond. This observation may contribute to a better understanding of the more selective binding of o-OCH3 arylpiperazine derivatives to the 5-HT1A receptor.

AS3MT, GSTO, and PNP polymorphisms: impact on arsenic methylation and implications for disease susceptibility.

PubMed

Antonelli, Ray; Shao, Kan; Thomas, David J; Sams, Reeder; Cowden, John

2014-07-01

Oral exposure to inorganic arsenic (iAs) is associated with adverse health effects. Epidemiological studies suggest differences in susceptibility to these health effects, possibly due to genotypic variation. Genetic polymorphisms in iAs metabolism could lead to increased susceptibility by altering urinary iAs metabolite concentrations. To examine the impact of genotypic polymorphisms on iAs metabolism. We screened 360 publications from PubMed and Web of Science for data on urinary mono- and dimethylated arsenic (MMA and DMA) percentages and polymorphic genes encoding proteins that are hypothesized to play roles in arsenic metabolism. The genes we examined were arsenic (+3) methyltransferase (AS3MT), glutathione-s-transferase omega (GSTO), and purine nucleoside phosphorylase (PNP). Relevant data were pooled to determine which polymorphisms are associated across studies with changes in urinary metabolite concentration. In our review, AS3MT polymorphisms rs3740390, rs11191439, and rs11191453 were associated with statistically significant changes in percent urinary MMA. Studies of GSTO polymorphisms did not indicate statistically significant associations with methylation, and there are insufficient data on PNP polymorphisms to evaluate their impact on metabolism. Collectively, these data support the hypothesis that AS3MT polymorphisms alter in vivo metabolite concentrations. Preliminary evidence suggests that AS3MT genetic polymorphisms may impact disease susceptibility. GSTO polymorphisms were not associated with iAs-associated health outcomes. Additional data are needed to evaluate the association between PNP polymorphisms and iAs-associated health outcomes. Delineation of these relationships may inform iAs mode(s) of action and the approach for evaluating low-dose health effects for iAs. Genotype impacts urinary iAs metabolite concentrations and may be a potential mechanism for iAs-related disease susceptibility. Published by Elsevier Inc.

Renoprotective effects of febuxostat in hyperuricemic patients with chronic kidney disease: a parallel-group, randomized, controlled trial.

PubMed

Tanaka, Kenichi; Nakayama, Masaaki; Kanno, Makoto; Kimura, Hiroshi; Watanabe, Kimio; Tani, Yoshihiro; Hayashi, Yoshimitsu; Asahi, Koichi; Terawaki, Hiroyuki; Watanabe, Tsuyoshi

2015-12-01

Hyperuricemia is associated with the onset of chronic kidney disease (CKD) and renal disease progression. Febuxostat, a novel, non-purine, selective xanthine oxidase inhibitor, has been reported to have a stronger effect on hyperuricemia than conventional therapy with allopurinol. However, few data are available regarding the clinical effect of febuxostat in patients with CKD. A prospective, randomized, open-label, parallel-group trial was conducted in hyperuricemic patients with stage 3 CKD. Patients were randomly assigned to treatment with febuxostat (n = 21) or to continue conventional therapy (n = 19). Treatment was continued for 12 weeks. The efficacy of febuxostat was determined by monitoring serum uric acid (UA) levels, blood pressures, renal function, and urinary protein levels. In addition, urinary liver-type fatty acid-binding protein (L-FABP), urinary albumin, urinary beta 2 microglobulin (β2MG), and serum high sensitivity C-reactive protein were measured before and 12 weeks after febuxostat was added to the treatment. Febuxostat resulted in a significantly greater reduction in serum UA (-2.2 mg/dL) than conventional therapy (-0.3 mg/dL, P < 0.001). Serum creatinine and estimated glomerular filtration rate changed little during the study period in each group. However, treatment with febuxostat for 12 weeks reduced the urinary levels of L-FABP, albumin, and β2MG, whereas the levels of these markers did not change in the control group. Febuxostat reduced serum UA levels more effectively than conventional therapy and might have a renoprotective effect in hyperuricemic patients with CKD. Further studies should clarify whether febuxostat prevents the progression of renal disease and improves the prognosis of CKD.

Targeting a Novel Plasmodium falciparum Purine Recycling Pathway with Specific Immucillins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ting, L; Shi, W; Lewandowicz, A

Plasmodium falciparum is unable to synthesize purine bases and relies upon purine salvage and purine recycling to meet its purine needs. We report that purines formed as products of the polyamine pathway are recycled in a novel pathway in which 5'-methylthioinosine is generated by adenosine deaminase. The action of P. falciparum purine nucleoside phosphorylase is a convergent step of purine salvage, converting both 5'-methylthioinosine and inosine to hypoxanthine. We used accelerator mass spectrometry to verify that 5'-methylthioinosine is an active nucleic acid precursor in P. falciparum. Prior studies have shown that inhibitors of purine salvage enzymes kill malaria, but potentmore » malaria-specific inhibitors of these enzymes have not previously been described. 5'-methylthio-Immucillin-H, a transition state analogue inhibitor that is selective for malarial over human purine nucleoside phosphorylase, kills P. falciparum in culture. Immucillins are currently in clinical trials for other indications and may have application as antimalarials.« less

Trisubstituted purine inhibitors of PDGFRα and their antileukemic activity in the human eosinophilic cell line EOL-1.

PubMed

Malínková, Veronika; Řezníčková, Eva; Jorda, Radek; Gucký, Tomáš; Kryštof, Vladimír

2017-12-15

Inhibition of protein kinases is a validated concept for pharmacological intervention in cancers. Many kinase inhibitors have been approved for clinical use, but their practical application is often limited. Here, we describe a collection of 23 novel 2,6,9-trisubstituted purine derivatives with nanomolar inhibitory activities against PDGFRα, a receptor tyrosine kinase often found constitutively activated in various tumours. The compounds demonstrated strong and selective cytotoxicity in the human eosinophilic leukemia cell line EOL-1, whereas several other cell lines were substantially less sensitive. The cytotoxicity in EOL-1, which is known to express the FIP1L1-PDGFRA fusion gene encoding an oncogenic kinase, correlated significantly with PDGFRα inhibition. EOL-1 cells treated with the compounds also exhibited dose-dependent inhibition of PDGFRα autophosphorylation and suppression of its downstream signaling pathways with concomitant G 1 phase arrest, confirming the proposed mechanism of action. Our results show that substituted purines can be used as platforms for preparing tyrosine kinase inhibitors with specific activity towards eosinophilic leukemia. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oxidizing action of purine N-oxide esters.

PubMed

Stöhrer, G; Salemnick, G

1975-01-01

A technique involving O-acetylation of purine N-oxide derivatives in buffered aqueous solutions has permitted studies of the reactivity of many compounds for which the O-acetyl derivatives are not otherwise available. The oxidizing properties of a variety of N-acetoxypurines have been measured through their ability to oxidize iodide ion ot iodine, a reaction which is representative of a more general oxidizing ability. Those esters that oxidize iodide ion also catalyze the autoxidation of sulfite, a property characteristic of radicals. The same esters also oxidize cysteine to cysteic acid and tryptophan, tyrosine, and uric acid to yet uncharacterized products. Their oxidizing reactivity was compared with the ability of the same esters to react as electrophiles in another assay that measured the rate of formation of pyridine substitution products. The sulfate ester of 3-hydroxyxanthine has been synthesized. Its reactivity is qualitatively the same as that of 3-acetoxyxanthine but proceeds at a higher rate. Syntheses of S-(8-xanthyl)-N-acetylcysteine, 8-(2-hydroxyethylthio)xanthine, and 1-methyl-8-mehtylmercaptoguanine are also described.

In Vivo Cardiovascular Pharmacology of 2′,3′-cAMP, 2′-AMP, and 3′-AMP in the Rat

PubMed Central

Mi, Zaichuan

2013-01-01

The naturally occurring purine 2′,3′-cAMP is metabolized in vitro to 2′-AMP and 3′-AMP, which are subsequently metabolized to adenosine. Whether in vivo 2′,3′-cAMP, 2′-AMP, or 3′-AMP are rapidly converted to adenosine and exert rapid effects via adenosine receptors is unknown. To address this question, we compared the cardiovascular and renal effects of 2′,3′-cAMP, 2′-AMP, 3′-AMP, 3′,5′-cAMP, 5′-AMP, and adenosine in vivo in the rat. Purines were infused intravenously while monitoring mean arterial blood pressure (MABP), heart rate (HR), cardiac output, and renal and mesenteric blood flows. Total peripheral (TPR), renal vascular (RVR), and mesenteric vascular (MVR) resistances were calculated. Urine was collected for determination of urine excretion rate [urine volume (UV)]. When sufficient urine was available, the sodium excretion rate (Na+ER) and glomerular filtration rate (GFR) were determined. 2′,3′-cAMP, 2′-AMP, and 3′-AMP dose-dependently and profoundly reduced MABP, HR, TPR, and MVR with efficacy and potency similar to adenosine and 5′-AMP. These effects of 2′,3′-cAMP, 2′-AMP, and 3′-AMP were attenuated by blockade of adenosine receptors with 1,3-dipropyl-8-(p-sulfophenyl)xanthine. 2′,3′-cAMP, 2′-AMP, 3′-AMP, adenosine, and 5′-AMP variably affected RVR, but profoundly (nearly 100%) decreased UV at higher doses. GFR and Na+ER could be measured at the lower doses and were suppressed by 2′,3′-cAMP, 2′-AMP, and 3′-AMP, but not by adenosine or 5′-AMP. 2′,3′-cAMP increased urinary excretion rates of 2′-AMP, 3′-AMP, and adenosine. 3′,5′-cAMP exerted no adverse hemodynamic effects yet increased urinary adenosine as efficiently as 2′,3′-cAMP. Conclusions: In vivo 2′,3′-cAMP is rapidly converted to adenosine. Because both cAMPs increase adenosine in the urinary compartment, these agents may provide unique therapeutic opportunities. PMID:23759508

Recent advances of pyrrolopyridines derivatives: a patent and literature review.

PubMed

El-Gamal, Mohammed I; Anbar, Hanan S

2017-05-01

Several pyrrolopyridines or azaindoles have been reported in the literature as biologically-active molecules. Most of them are anticancer agents, and few possess other therapeutic effects. Areas covered: The most recent biologically-active pyrrolopyridine derivatives have been reviewed from the patents and research articles published from 2010 to the mid of 2016. Their structural and biological features have been explained. In general, the pyrrolopyridine scaffold mimics the purine ring of the ATP molecule. So the well-designed pyrrolopyridine analogues can successfully act as kinase inhibitors for treatment of cancer and/or other diseases. The most successful pyrrolopyridine derivative that is currently used in the market is vemurafenib, which is used for treatment of melanoma. Its chemical and biological features have been reviewed and explained. Expert opinion: The heterocyclic pyrrolopyridine nucleus mimics the purine ring of ATP. So they can work as inhibitors of the kinase at hinge region. Due to the structural similarity with ATP, these pyrrolopyridine derivatives are estimated to be non-selective kinase inhibitors. The selectivity is conferred mainly from the different substituents attached to the azaindole nucleus. More details are presented in the 'Expert Opinion' section at the end of this article. This section covers the chemistry and the biological properties of therapeutically-efficient pyrrolopyridine-possessing compounds.

Activation and inhibition of CTP synthase from Trypanosoma brucei, the causative agent of African sleeping sickness.

PubMed

Steeves, Craig H; Bearne, Stephen L

2011-09-15

CTP Synthase from Trypanosoma brucei (TbCTPS) catalyzes the conversion of UTP to CTP and is a recognized target for the development of antiprotozoal agents. GTP activates glutamine-dependent CTP formation catalyzed by TbCTPS at concentrations below 0.2 mM, but inhibits this activity at concentrations above 0.2 mM. TbCTPS catalyzes ammonia-dependent CTP formation, which is inhibited by purine derivatives such as GTP, guanosine, caffeine, and uric acid with IC(50) values of 460, 380, 480, and 100 μM, respectively. These observations suggest that the purine ring may serve as a useful scaffold for the development of inhibitors of trypanosomal CTP synthase. Copyright © 2011 Elsevier Ltd. All rights reserved.

1-(Benzenesulfonyl)-1,5-dihydro-4,1-benzoxazepine as a new scaffold for the design of antitumor compounds.

PubMed

Cruz-López, Olga; Ramírez, Alberto; Navarro, Saúl A; García, María A; Marchal, Juan A; Campos, Joaquín M; Conejo-García, Ana

2017-07-01

Bozepinib is a potent and selective anticancer compound which chemical structure is made up of a benzofused seven-membered ring and a purine moiety. We previously demonstrated that the purine fragment does not exert antiproliferative effect per se. A series of 1-(benzenesulfonyl)-4,1-benzoxazepine derivatives were synthesized in order to study the influence of the benzofused seven-membered ring in the biological activity of bozepinib by means of antiproliferative, cell cycle and apoptosis studies. Our results show that the methyleneoxy enamine sulfonyl function is essential in the antitumor activity of the structures and thus, it is a scaffold suitable for further modification with a view to obtain more potent antitumor compounds.

Contribution of creatine to protein homeostasis in athletes after endurance and sprint running.

PubMed

Tang, Fu-Chun; Chan, Chun-Chen; Kuo, Po-Ling

2014-02-01

Few studies have focused on the metabolic changes induced by creatine supplementation. This study investigated the effects of creatine supplementation on plasma and urinary metabolite changes of athletes after endurance and sprint running. Twelve male athletes (20.3 ± 1.4 y) performed two identical (65-70 % maximum heart rate reserved) 60 min running exercises (endurance trial) before and after creatine supplementation (12 g creatine monohydrate/day for 15 days), followed by a 5-day washout period. Subsequently, they performed two identical 100 m sprint running exercises (power trial) before and after 15 days of creatine supplementation in accordance with the supplementary protocol of the endurance trial. Body composition measurements were performed during the entire study. Plasma samples were examined for the concentrations of glucose, lactate, branched-chain amino acids (BCAAs), free-tryptophan (f-TRP), glutamine, alanine, hypoxanthine, and uric acid. Urinary samples were examined for the concentrations of hydroxyproline, 3-methylhistidine, urea nitrogen, and creatinine. Creatine supplementation significantly increased body weights of the athletes of endurance trial. Plasma lactate concentration and ratio of f-TRP/BCAAs after recovery from endurance running were significantly decreased with creatine supplementation. Plasma purine metabolites (the sum of hypoxanthine and uric acid), glutamine, urinary 3-methylhistidine, and urea nitrogen concentrations tended to decrease before running in trials with creatine supplements. After running, urinary hydroxyproline concentration significantly increased in the power trial with creatine supplements. The findings suggest that creatine supplementation tended to decrease muscle glycogen and protein degradation, especially after endurance exercise. However, creatine supplementation might induce collagen proteolysis in athletes after sprint running.

Gas Chromatography-Mass Spectrometry for Metabolite Profiling of Japanese Black Cattle Naturally Contaminated with Zearalenone and Sterigmatocystin.

PubMed

Toda, Katsuki; Kokushi, Emiko; Uno, Seiichi; Shiiba, Ayaka; Hasunuma, Hiroshi; Fushimi, Yasuo; Wijayagunawardane, Missaka P B; Zhang, Chunhua; Yamato, Osamu; Taniguchi, Masayasu; Fink-Gremmels, Johanna; Takagi, Mitsuhiro

2017-09-21

The objective of this study was to evaluate the metabolic profile of cattle fed with or without zearalenone (ZEN) and sterigmatocystin (STC)-contaminated diets using a gas chromatography-mass spectrometry metabolomics approach. Urinary samples were collected from individual animals ( n = 6 per herd) from fattening female Japanese Black (JB) cattle herds (23 months old, 550-600 kg). Herd 1 had persistently high urinary ZEN and STC concentrations due to the presence of contaminated rice straw. Herd 2, the second female JB fattening herd (23 months old, 550-600 kg), received the same dietary feed as Herd 1, with non-contaminated rice straw. Urine samples were collected from Herd 1, two weeks after the contaminated rice straw was replaced with uncontaminated rice straw (Herd 1N). Identified metabolites were subjected to principal component analysis (PCA) and ANOVA. The PCA revealed that the effects on cattle metabolites depended on ZEN and STC concentrations. The contamination of cattle feed with multiple mycotoxins may alter systemic metabolic processes, including metabolites associated with ATP generation, amino acids, glycine-conjugates, organic acids, and purine bases. The results obtained from Herd 1N indicate that a two-week remedy period was not sufficient to improve the levels of urinary metabolites, suggesting that chronic contamination with mycotoxins may have long-term harmful effects on the systemic metabolism of cattle.

Gas Chromatography-Mass Spectrometry for Metabolite Profiling of Japanese Black Cattle Naturally Contaminated with Zearalenone and Sterigmatocystin

PubMed Central

Toda, Katsuki; Kokushi, Emiko; Uno, Seiichi; Shiiba, Ayaka; Hasunuma, Hiroshi; Fushimi, Yasuo; Wijayagunawardane, Missaka P. B.; Zhang, Chunhua; Yamato, Osamu; Taniguchi, Masayasu; Fink-Gremmels, Johanna; Takagi, Mitsuhiro

2017-01-01

The objective of this study was to evaluate the metabolic profile of cattle fed with or without zearalenone (ZEN) and sterigmatocystin (STC)-contaminated diets using a gas chromatography-mass spectrometry metabolomics approach. Urinary samples were collected from individual animals (n = 6 per herd) from fattening female Japanese Black (JB) cattle herds (23 months old, 550–600 kg). Herd 1 had persistently high urinary ZEN and STC concentrations due to the presence of contaminated rice straw. Herd 2, the second female JB fattening herd (23 months old, 550–600 kg), received the same dietary feed as Herd 1, with non-contaminated rice straw. Urine samples were collected from Herd 1, two weeks after the contaminated rice straw was replaced with uncontaminated rice straw (Herd 1N). Identified metabolites were subjected to principal component analysis (PCA) and ANOVA. The PCA revealed that the effects on cattle metabolites depended on ZEN and STC concentrations. The contamination of cattle feed with multiple mycotoxins may alter systemic metabolic processes, including metabolites associated with ATP generation, amino acids, glycine-conjugates, organic acids, and purine bases. The results obtained from Herd 1N indicate that a two-week remedy period was not sufficient to improve the levels of urinary metabolites, suggesting that chronic contamination with mycotoxins may have long-term harmful effects on the systemic metabolism of cattle. PMID:28934162

Purine synthesis promotes maintenance of brain tumor initiating cells in glioma.

PubMed

Wang, Xiuxing; Yang, Kailin; Xie, Qi; Wu, Qiulian; Mack, Stephen C; Shi, Yu; Kim, Leo J Y; Prager, Briana C; Flavahan, William A; Liu, Xiaojing; Singer, Meromit; Hubert, Christopher G; Miller, Tyler E; Zhou, Wenchao; Huang, Zhi; Fang, Xiaoguang; Regev, Aviv; Suvà, Mario L; Hwang, Tae Hyun; Locasale, Jason W; Bao, Shideng; Rich, Jeremy N

2017-05-01

Brain tumor initiating cells (BTICs), also known as cancer stem cells, hijack high-affinity glucose uptake active normally in neurons to maintain energy demands. Here we link metabolic dysregulation in human BTICs to a nexus between MYC and de novo purine synthesis, mediating glucose-sustained anabolic metabolism. Inhibiting purine synthesis abrogated BTIC growth, self-renewal and in vivo tumor formation by depleting intracellular pools of purine nucleotides, supporting purine synthesis as a potential therapeutic point of fragility. In contrast, differentiated glioma cells were unaffected by the targeting of purine biosynthetic enzymes, suggesting selective dependence of BTICs. MYC coordinated the control of purine synthetic enzymes, supporting its role in metabolic reprogramming. Elevated expression of purine synthetic enzymes correlated with poor prognosis in glioblastoma patients. Collectively, our results suggest that stem-like glioma cells reprogram their metabolism to self-renew and fuel the tumor hierarchy, revealing potential BTIC cancer dependencies amenable to targeted therapy.

Importance of specific purine amino and hydroxyl groups for efficient cleavage by a hammerhead ribozyme.

PubMed Central

Fu, D J; McLaughlin, L W

1992-01-01

Eight modified ribozymes of 19 residues have been prepared with individual purine amino or hydroxyl groups excised. The modified ribozymes were chemically synthesized with the substitution of a single 2'-deoxyadenosine, 2'-deoxyguanosine, inosine, or purine riboside for residues G10, A11, G13, or A14. Five of the modified ribozymes cleaved the 24-mer substrate with little change in rate as monitored by simple first-order kinetics. However, deletion of the 2-amino group at G10 (replacement with inosine) or deletion of either of the 2'-hydroxyls at G10 or G13 (replacement with 2'-deoxyguanosine) resulted in ribozymes with a drastic decrease in cleavage efficiency. Increasing the concentration of the Mg2+ cofactor from 10 mM to 50 mM significantly enhanced cleavage efficiency by these three derivatives. Steady-state kinetic assays for these three ribozymes indicated that the modifications result in both an increase in Km and a decrease in kcat. These results suggest that the exocyclic amino group at-G10 and the hydroxyls at G10 and G13 are important both for ribozyme-substrate binding and for the Mg(2+)-catalyzed cleavage reaction. PMID:1570323

Synthesis and preliminary biological evaluation of radiolabeled O6-benzylguanine derivatives, new potential PET imaging agents for the DNA repair protein O6-alkylguanine-DNA alkyltransferase in breast cancer.

PubMed

Zheng, Qi-Huang; Liu, Xuan; Fei, Xiangshu; Wang, Ji-Quan; Ohannesian, David W; Erickson, Leonard C; Stone, K Lee; Hutchins, Gary D

2003-05-01

Novel radiolabeled O(6)-benzylguanine (O(6)-BG) derivatives, 2-amino-6-O-[(11)C]-[(methoxymethyl)benzyloxy]-9-methyl purines ([(11)C]p-O(6)-AMMP, 1a; [(11)C]m-O(6)-AMMP, 1b; [(11)C]o-O(6)-AMMP, 1c), 2-amino-6-O-benzyloxy-9-[(11)C]-[(methoxycarbonyl)methyl]purine ([(11)C]ABMMP, 2), and 2-amino-6-O-benzyloxy-9-[(11)C]-[(4'-methoxycarbonyl)benzyl]purine ([(11)C]ABMBP, 3), have been synthesized for evaluation as new potential positron emission tomography (PET) imaging agents for the DNA repair protein O(6)-alkylguanine-DNA alkyltransferase (AGT) in breast cancer. The appropriate precursors for radiolabeling were obtained in two to three steps from starting material 2-amino-6-chloropurine with moderate to excellent chemical yields. Tracers were prepared by O-[(11)C]methylation of hydroxymethyl or acid precursors using [(11)C]methyl triflate. Pure target compounds were isolated by solid-phase extraction (SPE) purification procedure in 45-65% radiochemical yields (decay corrected to end of bombardment), and a synthesis time of 20-25 min. The activity of unlabeled standard samples of 1-3 was evaluated via an in vitro AGT oligonucleotide assay. Preliminary findings from biological assay indicate the synthesized analogs have similar strong inhibitory effectiveness on AGT in comparison with the parent compound O(6)-BG. The results warrant further evaluation of these radiotracers as new potential PET imaging agents for the DNA repair protein AGT in breast cancer in vivo.

Prolonged fasting increases purine recycling in post-weaned northern elephant seals.

PubMed

Soñanez-Organis, José Guadalupe; Vázquez-Medina, José Pablo; Zenteno-Savín, Tania; Aguilar, Andres; Crocker, Daniel E; Ortiz, Rudy M

2012-05-01

Northern elephant seals are naturally adapted to prolonged periods (1-2 months) of absolute food and water deprivation (fasting). In terrestrial mammals, food deprivation stimulates ATP degradation and decreases ATP synthesis, resulting in the accumulation of purines (ATP degradation byproducts). Hypoxanthine-guanine phosphoribosyl transferase (HGPRT) salvages ATP by recycling the purine degradation products derived from xanthine oxidase (XO) metabolism, which also promotes oxidant production. The contributions of HGPRT to purine recycling during prolonged food deprivation in marine mammals are not well defined. In the present study we cloned and characterized the complete and partial cDNA sequences that encode for HGPRT and xanthine oxidoreductase (XOR) in northern elephant seals. We also measured XO protein expression and circulating activity, along with xanthine and hypoxanthine plasma content in fasting northern elephant seal pups. Blood, adipose and muscle tissue samples were collected from animals after 1, 3, 5 and 7 weeks of their natural post-weaning fast. The complete HGPRT and partial XOR cDNA sequences are 771 and 345 bp long and encode proteins of 218 and 115 amino acids, respectively, with conserved domains important for their function and regulation. XOR mRNA and XO protein expression increased 3-fold and 1.7-fold with fasting, respectively, whereas HGPRT mRNA (4-fold) and protein (2-fold) expression increased after 7 weeks in adipose tissue and muscle. Plasma xanthine (3-fold) and hypoxanthine (2.5-fold) levels, and XO (1.7- to 20-fold) and HGPRT (1.5- to 1.7-fold) activities increased during the last 2 weeks of fasting. Results suggest that prolonged fasting in elephant seal pups is associated with increased capacity to recycle purines, which may contribute to ameliorating oxidant production and enhancing the supply of ATP, both of which would be beneficial during prolonged food deprivation and appear to be adaptive in this species.

Prolonged fasting increases purine recycling in post-weaned northern elephant seals

PubMed Central

Soñanez-Organis, José Guadalupe; Vázquez-Medina, José Pablo; Zenteno-Savín, Tania; Aguilar, Andres; Crocker, Daniel E.; Ortiz, Rudy M.

2012-01-01

SUMMARY Northern elephant seals are naturally adapted to prolonged periods (1–2 months) of absolute food and water deprivation (fasting). In terrestrial mammals, food deprivation stimulates ATP degradation and decreases ATP synthesis, resulting in the accumulation of purines (ATP degradation byproducts). Hypoxanthine-guanine phosphoribosyl transferase (HGPRT) salvages ATP by recycling the purine degradation products derived from xanthine oxidase (XO) metabolism, which also promotes oxidant production. The contributions of HGPRT to purine recycling during prolonged food deprivation in marine mammals are not well defined. In the present study we cloned and characterized the complete and partial cDNA sequences that encode for HGPRT and xanthine oxidoreductase (XOR) in northern elephant seals. We also measured XO protein expression and circulating activity, along with xanthine and hypoxanthine plasma content in fasting northern elephant seal pups. Blood, adipose and muscle tissue samples were collected from animals after 1, 3, 5 and 7 weeks of their natural post-weaning fast. The complete HGPRT and partial XOR cDNA sequences are 771 and 345 bp long and encode proteins of 218 and 115 amino acids, respectively, with conserved domains important for their function and regulation. XOR mRNA and XO protein expression increased 3-fold and 1.7-fold with fasting, respectively, whereas HGPRT mRNA (4-fold) and protein (2-fold) expression increased after 7 weeks in adipose tissue and muscle. Plasma xanthine (3-fold) and hypoxanthine (2.5-fold) levels, and XO (1.7- to 20-fold) and HGPRT (1.5- to 1.7-fold) activities increased during the last 2 weeks of fasting. Results suggest that prolonged fasting in elephant seal pups is associated with increased capacity to recycle purines, which may contribute to ameliorating oxidant production and enhancing the supply of ATP, both of which would be beneficial during prolonged food deprivation and appear to be adaptive in this species. PMID:22496280

[Polymethylene derivatives of nucleic bases with omega-functional groups: VII. Cytotoxicity in the series of N-(2-oxocyclohexyl)-omega-oxoalkyl substituted purines and pyrimidines].

PubMed

Komissarov, V V; Volgareva, G M; Ol'shanskaia, Ia S; Chernyshova, M E; Zavalishina, L E; Frank, G A; Shtil', A A; Kritsyn, A M

2009-01-01

New polymethylene derivatives of nucleic bases with a beta-diketo function in the omega-position were obtained by alkylation of uracil, thymine, cytosine, hypoxanthine, adenine, and N(2)-isobutyryl guanine with 2-omega-chloroal-kanoyl)cyclohexanones. The physical and chemical characteristics of the compounds synthesized and their effect on the K562 and HCT116 tumor cell lines were studied.

Determination of four different purines and their content change in seafood by high-performance liquid chromatography.

PubMed

Qu, Xin; Sui, Jianxin; Mi, Nasha; Lin, Hong

2017-01-01

Seafood is regarded as a high-purine food that may induce gout, which has attracted extensive attention concerning its safety. Therefore, the aim of this study was to develop a simple and reliable method to determine the purine content in seafood and its change during storage to offer consumers healthy diet information. Chromatographic separation was carried out using Waters Atlantis dC 18 column, and potassium phosphate monobasic solution (0.02 mol L -1 , pH 3.6) as a mobile phase. The average recovery yields of four purines were 91.5-105.0%, and relative standard deviation values were around 1.8-6.5%. Shrimp and snail contained higher amounts of purine than fish and bivalves; the livers and skins of fish contained higher amounts of purine than muscles; and the main purine varied depending on the type of seafood. Also, purine content of seafood changed during storage. The purine content of seafood differed depending on species, body part and degree of freshness, which could recommend consumers a healthy diet, especially for people with hyperuricemia and gout. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Solid phase synthesis and antiprotozoal evaluation of di- and trisubstituted 5'-carboxamidoadenosine analogues.

PubMed

Rodenko, Boris; Detz, Remko J; Pinas, Victorine A; Lambertucci, Catia; Brun, Reto; Wanner, Martin J; Koomen, Gerrit-Jan

2006-03-01

The rapid increase of resistance to drugs commonly used in the treatment of tropical diseases such as malaria and African sleeping sickness calls for the prompt development of new safe and efficacious drugs. The pathogenic protozoan parasites lack the capability of synthesising purines de novo and they take up preformed purines from their host through various transmembrane transporters. Adenosine derivatives constitute a class of potential therapeutics due to their selective internalisation by these transporters. Automated solid-phase synthesis can speed up the process of lead finding and we pursued the solid-phase synthesis of di- and trisubstituted 5'-carboxamidoadenosine derivatives by using a safety-catch approach. While efforts with Kenner's sulfonamide linker remained fruitless, successful application of the hydrazide safety-catch linker allowed the construction of two representative combinatorial libraries. Their antiprotozoal evaluation identified two compounds with promising activity: N(6)-benzyl-5'-N-phenylcarboxamidoadenosine with an IC(50) value of 0.91 microM against Trypanosoma brucei rhodesiense and N(6)-diphenylethyl-5'-phenylcarboxamidoadenosine with an IC(50) value of 1.8 microM against chloroquine resistant Plasmodium falciparum.

Folate-Dependent Purine Nucleotide Biosynthesis in Humans.

PubMed

Baggott, Joseph E; Tamura, Tsunenobu

2015-09-01

Purine nucleotide biosynthesis de novo (PNB) requires 2 folate-dependent transformylases-5'-phosphoribosyl-glycinamide (GAR) and 5'-phosphoribosyl-5-aminoimidazole-4-carboxamide (AICAR) transformylases-to introduce carbon 8 (C8) and carbon 2 (C2) into the purine ring. Both transformylases utilize 10-formyltetrahydrofolate (10-formyl-H4folate), where the formyl-carbon sources include ring-2-C of histidine, 3-C of serine, 2-C of glycine, and formate. Our findings in human studies indicate that glycine provides the carbon for GAR transformylase (exclusively C8), whereas histidine and formate are the predominant carbon sources for AICAR transformylase (C2). Contrary to the previous notion, these carbon sources may not supply a general 10-formyl-H4folate pool, which was believed to equally provide carbons to C8 and C2. To explain these phenomena, we postulate that GAR transformylase is in a complex with the trifunctional folate-metabolizing enzyme (TFM) and serine hydroxymethyltransferase to channel carbons of glycine and serine to C8. There is no evidence for channeling carbons of histidine and formate to AICAR transformylase (C2). GAR transformylase may require the TFM to furnish 10-formyl-H4folate immediately after its production from serine to protect its oxidation to 10-formyldihydrofolate (10-formyl-H2folate), whereas AICAR transformylase can utilize both 10-formyl-H2folate and 10-formyl-H4folate. Human liver may supply AICAR to AICAR transformylase in erythrocytes/erythroblasts. Incorporation of ring-2-C of histidine and formate into C2 of urinary uric acid presented a circadian rhythm with a peak in the morning, which corresponds to the maximum DNA synthesis in the bone marrow, and it may be useful in the timing of the administration of drugs that block PNB for the treatment of cancer and autoimmune disease. © 2015 American Society for Nutrition.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baggott, Joseph E.; Gorman, Gregory S.; Morgan, Sarah L.

To evaluate folate-dependent carbon incorporation into the purine ring, we measured {sup 13}C-enrichment independently at C{sub 2} and C{sub 8} of urinary uric acid (the final catabolite of purines) in a healthy male after an independent oral dose of [6RS]-5-[{sup 13}C]-formyltetrahydrofolate ([6RS]-5-H{sup 13}CO-H{sub 4}folate) or 10-H{sup 13}CO-7,8-dihydrofolate (10-H{sup 13}CO-H{sub 2}folate). The C{sub 2} position was {sup 13}C-enriched more than C{sub 8} after [6RS]-5-H{sup 13}CO-H{sub 4}folate, and C{sub 2} was exclusively enriched after 10-H{sup 13}CO-H{sub 2}folate. The enrichment of C{sub 2} was greater from [6RS]-5-H{sup 13}CO-H{sub 4}folate than 10-H{sup 13}CO-H{sub 2}folate using equimolar bioactive doses. Our data suggest that formyl Cmore » of [6RS]-10-H{sup 13}CO-H{sub 4}folate was not equally utilized by glycinamide ribotide transformylase (enriches C{sub 8}) and aminoimidazolecarboxamide ribotide (AICAR) transformylase (enriches C{sub 2}), and the formyl C of 10-H{sup 13}CO-H{sub 2}folate was exclusively used by AICAR transformylase. 10-HCO-H{sub 2}folate may function in vivo as the predominant substrate for AICAR transformylase in humans.« less

Erythrocytic adenosine monophosphate as an alternative purine source in Plasmodium falciparum.

PubMed

Cassera, María B; Hazleton, Keith Z; Riegelhaupt, Paul M; Merino, Emilio F; Luo, Minkui; Akabas, Myles H; Schramm, Vern L

2008-11-21

Plasmodium falciparum is a purine auxotroph, salvaging purines from erythrocytes for synthesis of RNA and DNA. Hypoxanthine is the key precursor for purine metabolism in Plasmodium. Inhibition of hypoxanthine-forming reactions in both erythrocytes and parasites is lethal to cultured P. falciparum. We observed that high concentrations of adenosine can rescue cultured parasites from purine nucleoside phosphorylase and adenosine deaminase blockade but not when erythrocyte adenosine kinase is also inhibited. P. falciparum lacks adenosine kinase but can salvage AMP synthesized in the erythrocyte cytoplasm to provide purines when both human and Plasmodium purine nucleoside phosphorylases and adenosine deaminases are inhibited. Transport studies in Xenopus laevis oocytes expressing the P. falciparum nucleoside transporter PfNT1 established that this transporter does not transport AMP. These metabolic patterns establish the existence of a novel nucleoside monophosphate transport pathway in P. falciparum.

Products of the direct reaction of the diazonium ion of a metabolite of the carcinogen N-nitrosomorpholine with purines of nucleosides and DNA.

PubMed

Zink, Charles N; Soissons, Nicolas; Fishbein, James C

2010-07-19

A number of putative purine nucleoside and nucleobase adducts of the diazonium ion derived from 3-hydroxy-N-nitrosomorpholine have been synthesized as dimethylacetals. These are converted, in most cases nearly quantitatively, to the aldehydes, or in two cases to their derivatives, on treatment with mild acid to yield standards for a quantitative investigation of alkylation of purine nucleosides and DNA by the above metabolite of the powerful carcinogen N-nitrosomorpholine. The stability of the resulting nucleobase ethoxyacetaldehyde (EA) adducts has been characterized under a number of conditions with respect to their propensity to decompose. The stabilities, compared to that of the previously characterized adduct of the model benzimidazole, are generally unexceptional. Deposition of adducts on purine nucleosides and DNA were quantified in reactions in which 3-hydroperoxy-N-nitrosomorpholine was reduced to the hydroxy metabolite by a water-soluble phosphine at 21 +/- 2 degrees C. The adduct profile is highly similar to that observed from simpler alpha-hydroxy metabolites of acyclic dialkylnitrosamines, with the three most abundant ethoxyacetaldehyde (EA) adducts in reactions of duplex DNA being N7-EA-Gua approximately O(6)-EA-Gua > N3-EA-Ade. The initial rate kinetics of formation of hydroxyethyl (HE) lesions from the initially formed EA lesions have been determined in the case of the major products in the cases of both the nucleoside and DNA adducts. The rates of formation of HE adducts are accelerated in DNA, relative to the nucleosides in the cases of the N7-EA-Ade, N7-EA-Gua, and O(6)-EA-Gua adducts by factors of 7, 14, and 54, respectively. The initial rates of depurination of the N3-EA-Ade, N7-EA-Gua, and N7-EA-Gua adducts have also been quantified, and they are unexceptional in comparison with what has been previously reported for simple alkyl adducts. The adduct profiles reported here stand in significant contrast to what has been reported previously for structurally closely related alpha-substituted cyclic nitrosamines. In part or whole, this may be due to methodological differences in the conduct of the present and previous reports.

Effects of different lipid sources on intake, digestibility and purine derivatives in hair lambs.

PubMed

Pereira, E S; Pereira, M W F; Arruda, P C L; Cabral, L S; Oliveira, R L; Mizubuti, I Y; Pinto, A P; Campos, A C N; Gadelha, C R F; Carneiro, M S S

2016-08-01

An experiment was conducted to evaluate the effects of different lipid sources on the nutrient intake, digestibility and purine derivative excretion of lambs. Thirty-five 60-day-old, male, non-castrated Santa Ines lambs with an initial average body weight (BW) of 13.00 ± 1.80 kg were used in a randomized complete block design with seven blocks and five treatments. The experimental treatments consisted of a control diet without supplemental lipids and four test diets with different lipid supplements, selected according to the degree of ruminal protection from hydrogenation: supplementation, being supplementation with whole cottonseed (WC), supplementation with cashew nut meal (CNM), supplementation with both cottonseed and cashew nut meal (WC-CNM) and supplementation with calcium salts of long-chain fatty acids (Ca-LCFA). The lambs were slaughtered after reaching 28 kg average BW for each treatment. The ether extract intake (EEI) was higher (p < 0.01) for the lipid supplemented compared to control diet lambs. Supplementation with WC decreased the digestibility of dry matter (DM), organic matter (OM), neutral detergent fibre (NDF) and total carbohydrate (TC) (p < 0.01), whereas supplementation with CNM, WC-CNM and Ca-LCFA reduced non-fibrous carbohydrate (NFC) digestibility (p < 0.01). The ether extract (EE) digestibility coefficient was higher with CNM, followed by Ca-LCFA and WC, when compared to WC-CNM and control diets. Nitrogen balance (NB) was not influenced (p > 0.05) by the different lipid sources. A lower purine derivative (PD) excretion and thus lower microbial protein supply (MPS) was observed for animals supplemented with Ca-LCFA (p < 0.01) compared to the WC-CNM and control diets. In conclusion, WC, CNM and WC-CNM supplementation did not have negative effects on MPS, although negative effects have been observed on nutrient digestibility. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Erythrocytic Adenosine Monophosphate as an Alternative Purine Source in Plasmodium falciparum*

PubMed Central

Cassera, María B.; Hazleton, Keith Z.; Riegelhaupt, Paul M.; Merino, Emilio F.; Luo, Minkui; Akabas, Myles H.; Schramm, Vern L.

2008-01-01

Plasmodium falciparum is a purine auxotroph, salvaging purines from erythrocytes for synthesis of RNA and DNA. Hypoxanthine is the key precursor for purine metabolism in Plasmodium. Inhibition of hypoxanthine-forming reactions in both erythrocytes and parasites is lethal to cultured P. falciparum. We observed that high concentrations of adenosine can rescue cultured parasites from purine nucleoside phosphorylase and adenosine deaminase blockade but not when erythrocyte adenosine kinase is also inhibited. P. falciparum lacks adenosine kinase but can salvage AMP synthesized in the erythrocyte cytoplasm to provide purines when both human and Plasmodium purine nucleoside phosphorylases and adenosine deaminases are inhibited. Transport studies in Xenopus laevis oocytes expressing the P. falciparum nucleoside transporter PfNT1 established that this transporter does not transport AMP. These metabolic patterns establish the existence of a novel nucleoside monophosphate transport pathway in P. falciparum. PMID:18799466

The substrate specificity of purine phosphoribosyltransferases in Schizosaccharomyces pombe

PubMed Central

De Groodt, A.; Whitehead, E. P.; Heslot, H.; Poirier, L.

1971-01-01

1. The activities of the purine phosphoribosyltransferases (EC 2.4.2.7 and 2.4.2.8) in purine-analogue-resistant mutants of Schizosaccharomyces pombe were checked. An 8-azathioxanthine-resistant mutant lacked hypoxanthine phosphoribosyltransferase, xanthine phosphoribosyltransferase and guanine phosphoribosyltransferase activities (EC 2.4.2.8) and appeared to carry a single mutation. Two 2,6-diaminopurine-resistant mutants retained these activities but lacked adenine phosphoribosyltransferase activity (EC 2.4.2.7). This evidence, together with data on purification and heat-inactivation patterns of phosphoribosyltransferase activities towards the various purines, strongly suggests that there are two phosphoribosyltransferase enzymes for purine bases in Schiz. pombe, one active with adenine, the other with hypoxanthine, xanthine and guanine. 2. Neither growth-medium supplements of purines nor mutations on genes involved in the pathway for new biosynthesis of purine have any influence on the amount of hypoxanthine–xanthine–guanine phosphoribosyltransferase produced by this organism. PMID:5123876

40 CFR 721.4685 - Substituted purine metal salt (generic name).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted purine metal salt (generic... Specific Chemical Substances § 721.4685 Substituted purine metal salt (generic name). (a) Chemical... as a substituted purine metal salt (PMN P-95-175) is subject to reporting under this section for the...

Metabolism of Exogenous Purine Bases and Nucleosides by Salmonella typhimurium

PubMed Central

Hoffmeyer, J.; Neuhard, J.

1971-01-01

Purine-requiring mutants of Salmonella typhimurium LT2 containing additional mutations in either adenosine deaminase or purine nucleoside phosphorylase have been constructed. From studies of the ability of these mutants to utilize different purine compounds as the sole source of purines, the following conclusions may be drawn. (i) S. typhimurium does not contain physiologically significant amounts of adenine deaminase and adenosine kinase activities. (ii) The presence of inosine and guanosine kinase activities in vivo was established, although the former activity appears to be of minor significance for inosine metabolism. (iii) The utilization of exogenous purine deoxyribonucleosides is entirely dependent on a functional purine nucleoside phosphorylase. (iv) The pathway by which exogenous adenine is converted to guanine nucleotides in the presence of histidine requires a functional purine nucleoside phosphorylase. Evidence is presented that this pathway involves the conversion of adenine to adenosine, followed by deamination to inosine and subsequent phosphorolysis to hypoxanthine. Hypoxanthine is then converted to inosine monophosphate by inosine monophosphate pyrophosphorylase. The rate-limiting step in this pathway is the synthesis of adenosine from adenine due to lack of endogenous ribose-l-phosphate. PMID:4928005

Simultaneous quantification by HPLC of purines in umami soup stock and evaluation of their effects on extracellular and intracellular purine metabolism.

PubMed

Fukuuchi, T; Iyama, N; Yamaoka, N; Kaneko, K

2018-04-13

Ribonucleotide flavor enhancers such as inosine monophosphate (IMP) and guanosine monophosphate (GMP) provide umami taste, similarly to glutamine. Japanese cuisine frequently uses soup stocks containing these nucleotides to enhance umami. We quantified 18 types of purines (nucleotides, nucleosides, and purine bases) in three soup stocks (chicken, consommé, and dried bonito soup). IMP was the most abundant purine in all umami soup stocks, followed by hypoxanthine, inosine, and GMP. The IMP content of dried bonito soup was the highest of the three soup stocks. We also evaluated the effects of these purines on extracellular and intracellular purine metabolism in HepG2 cells after adding each umami soup stock to the cells. An increase in inosine and hypoxanthine was evident 1 h and 4 h after soup stock addition, and a low amount of xanthine and guanosine was observed in the extracellular medium. The addition of chicken soup stock resulted in increased intracellular and extracellular levels of uric acid and guanosine. Purine metabolism may be affected by ingredients present in soups.

Purine Restriction Induces Pronounced Translational Upregulation of the NT1 Adenosine/Pyrimidine Nucleoside Transporter in Leishmania major

PubMed Central

Ortiz, Diana; Valdés, Raquel; Sanchez, Marco A.; Hayenga, Johanna; Elya, Carolyn; Detke, Siegfried; Landfear, Scott M.

2010-01-01

Summary Leishmania and other parasitic protozoa are unable to synthesize purines de novo and are reliant upon purine nucleoside and nucleobase transporters to import preformed purines from their hosts. To study the roles of the four purine permeases NT1-NT4 in Leishmania major, null mutants in each transporter gene were prepared and the effect of each gene deletion on purine uptake was monitored. Deletion of the NT3 purine nucleobase transporter gene or both NT3 and the NT2 nucleoside transporter gene resulted in pronounced upregulation of adenosine and uridine uptake mediated by the NT1 permease and also induced up to a 200-fold enhancement in the level of the NT1 protein but not mRNA. A similar level of upregulation of NT1 was achieved in wild type promastigotes that were transferred to medium deficient in purines. Pulse labeling and treatment of cells with the translation inhibitor cycloheximide revealed that control of NT1 expression occurs primarily at the level of translation and not protein turnover. These observations imply the existence of a translational control mechanism that enhances the ability of Leishmania parasites to import essential purines when they are present at limiting concentrations. PMID:20735779

Purine restriction induces pronounced translational upregulation of the NT1 adenosine/pyrimidine nucleoside transporter in Leishmania major.

PubMed

Ortiz, Diana; Valdés, Raquel; Sanchez, Marco A; Hayenga, Johanna; Elya, Carolyn; Detke, Siegfried; Landfear, Scott M

2010-10-01

Leishmania and other parasitic protozoa are unable to synthesize purines de novo and are reliant upon purine nucleoside and nucleobase transporters to import preformed purines from their hosts. To study the roles of the four purine permeases NT1-NT4 in Leishmania major, null mutants in each transporter gene were prepared and the effect of each gene deletion on purine uptake was monitored. Deletion of the NT3 purine nucleobase transporter gene or both NT3 and the NT2 nucleoside transporter gene resulted in pronounced upregulation of adenosine and uridine uptake mediated by the NT1 permease and also induced up to a 200-fold enhancement in the level of the NT1 protein but not mRNA. A similar level of upregulation of NT1 was achieved in wild-type promastigotes that were transferred to medium deficient in purines. Pulse labelling and treatment of cells with the translation inhibitor cycloheximide revealed that control of NT1 expression occurs primarily at the level of translation and not protein turnover. These observations imply the existence of a translational control mechanism that enhances the ability of Leishmania parasites to import essential purines when they are present at limiting concentrations. © 2010 Blackwell Publishing Ltd.

Optimum nutrition for kidney stone disease.

PubMed

Heilberg, Ita P; Goldfarb, David S

2013-03-01

We summarize the data regarding the associations of individual dietary components with kidney stones and the effects on 24-hour urinary profiles. The therapeutic recommendations for stone prevention that result from these studies are applied where possible to stones of specific composition. Idiopathic calcium oxalate stone-formers are advised to reduce ingestion of animal protein, oxalate, and sodium while maintaining intake of 800 to 1200 mg of calcium and increasing consumption of citrate and potassium. There are few data regarding dietary therapy of calcium phosphate stones. Whether the inhibitory effect of citrate sufficiently counteracts increasing urine pH to justify more intake of potassium and citrate is not clear. Reduction of sodium intake to decrease urinary calcium excretion would also be expected to decrease calcium phosphate stone recurrence. Conversely, the most important urine variable in the causation of uric acid stones is low urine pH, linked to insulin resistance as a component of obesity and the metabolic syndrome. The mainstay of therapy is weight loss and urinary alkalinization provided by a more vegetarian diet. Reduction in animal protein intake will reduce purine ingestion and uric acid excretion. For cystine stones, restriction of animal protein is associated with reduction in intake of the cystine precursor methionine as well as cystine. Reduction of urine sodium results in less urine cystine. Ingestion of vegetables high in organic anion content, such as citrate and malate, should be associated with higher urine pH and fewer stones because the amino acid cystine is soluble in more alkaline urine. Because of their infectious origin, diet has no definitive role for struvite stones except for avoiding urinary alkalinization, which may worsen their development. Published by Elsevier Inc.

Beta-hydroxyphosphonate ribonucleoside analogues derived from 4-substituted-1,2,3-triazoles as IMP/GMP mimics: synthesis and biological evaluation

PubMed Central

Nguyen Van, Tai; Hospital, Audrey; Lionne, Corinne; Jordheim, Lars P; Dumontet, Charles; Périgaud, Christian; Chaloin, Laurent

2016-01-01

Summary A series of seventeen β-hydroxyphosphonate ribonucleoside analogues containing 4-substituted-1,2,3-triazoles was synthesized and fully characterized. Such compounds were designed as potential inhibitors of the cytosolic 5’-nucleotidase II (cN-II), an enzyme involved in the regulation of purine nucleotide pools. NMR and molecular modelling studies showed that a few derivatives adopted similar structural features to IMP or GMP. Five derivatives were identified as modest inhibitors with 53 to 64% of cN-II inhibition at 1 mM. PMID:27559400

Effects of supplementing rare earth element cerium on rumen fermentation, nutrient digestibility, nitrogen balance and plasma biochemical parameters in beef cattle.

PubMed

Lin, S X; Wei, C; Zhao, G Y; Zhang, T T; Yang, K

2015-12-01

The objectives of the trial were to investigate the effects of supplementing rare earth element (REE) cerium (Ce) on rumen fermentation, nutrient digestibility, methane (CH4 ) production, nitrogen (N) balance and plasma biochemical parameters in beef cattle. Four Simmental male cattle, aged at 14 months, with initial liveweight of 355 ± 8 kg and fitted with permanent rumen cannulas, were used as experimental animals. The cattle were fed with a total mixed ration (TMR) composed of concentrate mixture and corn silage. Four levels of cerium chloride (CeCl3 ·7H2 O, purity 99.9%), that is 0, 80, 160 and 240 mg CeCl3 /kg DM, were added to basal ration in a 4 × 4 Latin square design. Each experimental period lasted 15 days, of which the first 12 days were for pre-treatment and the last 3 days were for sampling. The results showed that supplementing CeCl3 at 160 or 240 mg/kg DM increased neutral detergent fibre (NDF) digestibility (p < 0.05) and tended to increased acid detergent fibre (ADF) digestibility (p = 0.083). Supplementing CeCl3 at 80, 160 or 240 mg/kg DM decreased the molar ratio of rumen acetate to propionate linearly (p < 0.05). Supplementing CeCl3 at 160 or 240 mg/kg DM decreased total N excretion, urinary N excretion and increased N retention (p < 0.05), increased excretion of total urinary purine derivatives (PD) (p < 0.05) and decreased CH4 /kg DMI (p < 0.05). In conclusion, supplementing CeCl3 at 160 or 240 mg/kg DM in the ration of beef cattle increased the digestibility of NDF, decreased the molar ratio of rumen acetate to propionate, increased N retention and microbial N flow and decreased CH4 /kg DMI. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

Molecular and functional characterization of the first nucleobase transporter gene from African trypanosomes.

PubMed

Henriques, Cristina; Sanchez, Marco A; Tryon, Rob; Landfear, Scott M

2003-08-31

African trypanosomes are unable to synthesize purines and depend upon purine nucleoside and nucleobase transporters to salvage these compounds from their hosts. To understand the crucial role of purine salvage in the survival of these parasites, a central objective is to identify and characterize all of the purine permeases that mediate uptake of these essential nutrients. We have cloned and functionally expressed in a purine nucleobase transport deficient strain of Saccharomyces cerevisiae a novel nucleobase transporter gene, TbNT8.1, from Trypanosoma brucei. The permease encoded by this gene mediates the uptake of hypoxanthine, adenine, guanine, and xanthine with Kms in the low micromolar range. The TbNT8.1 protein is a member of the equilibrative nucleoside transporter (ENT) family of permeases that occur in organisms as diverse as protozoa and mammals. TbNT8.1 is distinct from other ENT permeases that have been identified in trypanosomes in utilizing multiple purine nucleobases, rather than purine nucleosides, as substrates and is hence the first bona fide nucleobase permease identified in these parasites. Furthermore, unlike the mRNAs for other purine transporters, TbNT8.1 mRNA is significantly more abundant in insect stage procyclic forms than in mammalian stage bloodstream forms, and the TbNT8.1 permease thus may represent a major route for purine nucleobase uptake in procyclic trypanosomes.

Effects of breeds, tissues and genders on purine contents in pork and the relationships between purine content and other meat quality traits.

PubMed

Zheng, Min; Huang, Yizhong; Ji, Jiuxiu; Xiao, Shijun; Ma, Junwu; Huang, Lusheng

2018-09-01

The purine contents of animal foods are becoming widely concerned because excess intake of purine increases the risk of hyperuricemia and gout. In this study, we investigated the impacts of breed, tissue and sex on pork purine content and its correlations with multiple meat quality traits. Among six pig breeds, the average value of total purine contents (TP) in longissimus lumborum muscle was lowest in Chinese Laiwu pigs (114.2 mg/100 g) while highest in Chinese Bamaxiang mini pigs (139.3 mg/100 g). Considerable variations in TP were observed within most breeds, as well as among twelve pork organs with the range from 7 to 245 mg/100 g. However, no significant differences in TP were found between barrows and gilts. Intriguingly, lower purine content in meat was significantly associated with higher ultimate pH, better meat color and more abundant intramuscular fat content and marbling. The results thus suggest that the selection of low-purine pig species is available, which may simultaneously improve other meat quality traits. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Purine in common plant food in China].

PubMed

Rong, Shengzhong; Zou, Lina; Wang, Zhaoxu; Pan, Hongzhi; Yang, Yuexin

2012-01-01

To determine the content of purine in plant food in China with HPLC. HPLC analysis was applied on Waters Atlantis T3 column (4.6mm x 250mm x 5 microm), using 10.0 mmol/L NH4COOH (pH 3.6) and CH3OH (99%/1%) as mobile phase and running at a flow rate of 1.0 ml/min. The column temperature was 30 degrees C, and the detection wavelength was at 254nm. The content of purine varied significantly in different kinds of plant food. The content of purine in dried fungi and dried legumes and legume products was higher than that in other food, the content of purine in vegetables and vegetable products and fruits and fruit products was low. As a whole, the content of purine was: dried fungi and algae > dried legumes and legume products > nuts and fresh > seeds fungi and algae > cereal and cereals products > vegetables and vegetable products > fruit and fruit products > tubers, starches and products. The content of purine of dried fungi and algae and dried legumes and legume products in plant food was high. The content of purine was varied significantly in different kinds of plant food.

Increased PRPP synthetase activity in cultured rat hepatoma cells containing mutations in the hypoxanthine-guanine phosphoribosyltransferase gene.

PubMed

Graf, L H; McRoberts, J A; Harrison, T M; Martin, D W

1976-07-01

Nine independently derived clones of mutagenized rat hepatoma cells selected for resistance to 6-mercaptopurine (6-MP) or 6-thioguanine (6-ThioG) have been isolated. Each has severely reduced catalytic activity of hypoxanthine-guanine phosphoribosyltransferase (HPRT) and seven of them possess significantly increased activities of phosphoribosylpyrophosphate (PRPP) synthetase. The degrees of elevations of PRPP synthetase activities do not correlate with the degrees of deficiencies of HPRT activities. The cells from one of these clones, 1020/12, posses 40% of the normal HPRT catalytic activity and overproduce purines. We have extensively examined the cells from this clone. Immunotration studies of 1020/12 cells indicate that there is a mutation in the structural gene for HPRT. Although they possess increased specific catalytic activities of the enzyme. PRPP synthetase, the catalytic parameters, heat stability, and isoelectric pH of PRPP synthetase from 1020/12 cells are indistinguishable from those of the enzyme from wild-type cells. The cause of purine overproduction by 1020/12 cells appears to be the elevated PRPP synthetase activity, rather than a PRPP "sparing" effect stemming from reduced HPRT activity. Support for this idea is provided by the observation that the complete loss of HPRT activity in a clone derived from 1020/12 cells does not further enhance the levels of PRPP synthetase or purine overproduction. We propose that the elevated levels of PRPP synthetase activity in these HPRT deficient cells result from a mutational event in the structural gene for HPRT, and that this causes the disruption of a previously undescribed regulatory function of this gene on the expression of the PRPP synthetase gene.

In silico analysis of the amido phosphoribosyltransferase inhibition by PY873, PY899 and a derivative of isophthalic acid.

PubMed

Batool, Sidra; Nawaz, Muhammad Sulaman; Kamal, Mohammad A

2013-10-01

Selectively decreasing the availability of precursors for the de novo biosynthesis of purine nucleotides is a valid approach towards seeking a cure for leukaemia. Nucleotides and deoxynucleotides are required by living cells for syntheses of RNA, DNA, and cofactors such as NADP(+), FAD(+), coenzyme A and ATP. Nucleotides contain purine and pyrimidine bases, which can be synthesized through salvage pathway as well. Amido phosphoribosyltransferase (APRT), also known as glutamine phosphoribosylpyrophosphate amidotransferase (GPAT), is an enzyme that in humans is encoded by the PPAT (phosphoribosyl pyrophosphate amidotransferase) gene. APRT catalyzes the first committed step of the de novo pathway using its substrate, phosphoribosyl pyrophosphate (PRPP). As APRT is inhibited by many folate analogues, therefore, in this study we focused on the inhibitory effects of three folate analogues on APRT activity. This is extension of our previous wet lab work to analyze and dissect molecular interaction and inhibition mechanism using molecular modeling and docking tools in the current study. Comparative molecular docking studies were carried out for three diamino folate derivatives employing a model of the human enzyme that was built using the 3D structure of Bacillus subtilis APRT (PDB ID; 1GPH) as the template. Binding orientation of interactome indicates that all compounds having nominal cluster RMSD in same active site's deep narrow polar fissure. On the basis of comparative conformational analysis, electrostatic interaction, binding free energy and binding orientation of interactome, we support the possibility that these molecules could behave as APRT inhibitors and therefore may block purine de novo biosynthesis. Consequently, we suggest that PY899 is the most active biological compound that would be a more potent inhibitor for APRT inhibition than PY873 and DIA, which also confirms previous wet lab report.

Inhibitors of Leishmania mexicana CRK3 Cyclin-Dependent Kinase: Chemical Library Screen and Antileishmanial Activity

PubMed Central

Grant, Karen M.; Dunion, Morag H.; Yardley, Vanessa; Skaltsounis, Alexios-Leandros; Marko, Doris; Eisenbrand, Gerhard; Croft, Simon L.; Meijer, Laurent; Mottram, Jeremy C.

2004-01-01

The CRK3 cyclin-dependent kinase of Leishmania has been shown by genetic manipulation of the parasite to be essential for proliferation. We present data which demonstrate that chemical inhibition of CRK3 impairs the parasite's viability within macrophages, thus further validating CRK3 as a potential drug target. A microtiter plate-based histone H1 kinase assay was developed to screen CRK3 against a chemical library enriched for protein kinase inhibitors. Twenty-seven potent CRK3 inhibitors were discovered and screened against Leishmania donovani amastigotes in vitro. Sixteen of the CRK3 inhibitors displayed antileishmanial activity, with a 50% effective dose (ED50) of less than 10 μM. These compounds fell into four chemical classes: the 2,6,9-trisubstituted purines, including the C-2-alkynylated purines; the indirubins; the paullones; and derivatives of the nonspecific kinase inhibitor staurosporine. The paullones and staurosporine derivatives were toxic to macrophages. The 2,6,9-trisubstituted purines inhibited CRK3 in vitro, with 50% inhibitory concentrations ranging from high nanomolar to low micromolar concentrations. The most potent inhibitors of CRK3 (compounds 98/516 and 97/344) belonged to the indirubin class; the 50% inhibitory concentrations for these inhibitors were 16 and 47 nM, respectively, and the ED50s for these inhibitors were 5.8 and 7.6 μM, respectively. In culture, the indirubins caused growth arrest, a change in DNA content, and aberrant cell types, all consistent with the intracellular inhibition of a cyclin-dependent kinase and disruption of cell cycle control. Thus, use of chemical inhibitors supports genetic studies to confirm CRK3 as a validated drug target in Leishmania and provides pharmacophores for further drug development. PMID:15273118

Divergent prebiotic synthesis of pyrimidine and 8-oxo-purine ribonucleotides

NASA Astrophysics Data System (ADS)

Stairs, Shaun; Nikmal, Arif; Bučar, Dejan-Krešimir; Zheng, Shao-Liang; Szostak, Jack W.; Powner, Matthew W.

2017-05-01

Understanding prebiotic nucleotide synthesis is a long standing challenge thought to be essential to elucidating the origins of life on Earth. Recently, remarkable progress has been made, but to date all proposed syntheses account separately for the pyrimidine and purine ribonucleotides; no divergent synthesis from common precursors has been proposed. Moreover, the prebiotic syntheses of pyrimidine and purine nucleotides that have been demonstrated operate under mutually incompatible conditions. Here, we tackle this mutual incompatibility by recognizing that the 8-oxo-purines share an underlying generational parity with the pyrimidine nucleotides. We present a divergent synthesis of pyrimidine and 8-oxo-purine nucleotides starting from a common prebiotic precursor that yields the β-ribo-stereochemistry found in the sugar phosphate backbone of biological nucleic acids. The generational relationship between pyrimidine and 8-oxo-purine nucleotides suggests that 8-oxo-purine ribonucleotides may have played a key role in primordial nucleic acids prior to the emergence of the canonical nucleotides of biology.

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

PubMed

Ishikawa, Toshihisa; Aw, Wanping; Kaneko, Kiyoko

2013-11-04

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.

The Purine-Utilizing Bacterium Clostridium acidurici 9a: A Genome-Guided Metabolic Reconsideration

PubMed Central

Hartwich, Katrin; Poehlein, Anja; Daniel, Rolf

2012-01-01

Clostridium acidurici is an anaerobic, homoacetogenic bacterium, which is able to use purines such as uric acid as sole carbon, nitrogen, and energy source. Together with the two other known purinolytic clostridia C. cylindrosporum and C. purinilyticum, C. acidurici serves as a model organism for investigation of purine fermentation. Here, we present the first complete sequence and analysis of a genome derived from a purinolytic Clostridium. The genome of C. acidurici 9a consists of one chromosome (3,105,335 bp) and one small circular plasmid (2,913 bp). The lack of candidate genes encoding glycine reductase indicates that C. acidurici 9a uses the energetically less favorable glycine-serine-pyruvate pathway for glycine degradation. In accordance with the specialized lifestyle and the corresponding narrow substrate spectrum of C. acidurici 9a, the number of genes involved in carbohydrate transport and metabolism is significantly lower than in other clostridia such as C. acetobutylicum, C. saccharolyticum, and C. beijerinckii. The only amino acid that can be degraded by C. acidurici is glycine but growth on glycine only occurs in the presence of a fermentable purine. Nevertheless, the addition of glycine resulted in increased transcription levels of genes encoding enzymes involved in the glycine-serine-pyruvate pathway such as serine hydroxymethyltransferase and acetate kinase, whereas the transcription levels of formate dehydrogenase-encoding genes decreased. Sugars could not be utilized by C. acidurici but the full genetic repertoire for glycolysis was detected. In addition, genes encoding enzymes that mediate resistance against several antimicrobials and metals were identified. High resistance of C. acidurici towards bacitracin, acriflavine and azaleucine was experimentally confirmed. PMID:23240052

The purine-utilizing bacterium Clostridium acidurici 9a: a genome-guided metabolic reconsideration.

PubMed

Hartwich, Katrin; Poehlein, Anja; Daniel, Rolf

2012-01-01

Clostridium acidurici is an anaerobic, homoacetogenic bacterium, which is able to use purines such as uric acid as sole carbon, nitrogen, and energy source. Together with the two other known purinolytic clostridia C. cylindrosporum and C. purinilyticum, C. acidurici serves as a model organism for investigation of purine fermentation. Here, we present the first complete sequence and analysis of a genome derived from a purinolytic Clostridium. The genome of C. acidurici 9a consists of one chromosome (3,105,335 bp) and one small circular plasmid (2,913 bp). The lack of candidate genes encoding glycine reductase indicates that C. acidurici 9a uses the energetically less favorable glycine-serine-pyruvate pathway for glycine degradation. In accordance with the specialized lifestyle and the corresponding narrow substrate spectrum of C. acidurici 9a, the number of genes involved in carbohydrate transport and metabolism is significantly lower than in other clostridia such as C. acetobutylicum, C. saccharolyticum, and C. beijerinckii. The only amino acid that can be degraded by C. acidurici is glycine but growth on glycine only occurs in the presence of a fermentable purine. Nevertheless, the addition of glycine resulted in increased transcription levels of genes encoding enzymes involved in the glycine-serine-pyruvate pathway such as serine hydroxymethyltransferase and acetate kinase, whereas the transcription levels of formate dehydrogenase-encoding genes decreased. Sugars could not be utilized by C. acidurici but the full genetic repertoire for glycolysis was detected. In addition, genes encoding enzymes that mediate resistance against several antimicrobials and metals were identified. High resistance of C. acidurici towards bacitracin, acriflavine and azaleucine was experimentally confirmed.

Purine metabolism in response to hypoxic conditions associated with breath-hold diving and exercise in erythrocytes and plasma from bottlenose dolphins (Tursiops truncatus).

PubMed

Del Castillo Velasco-Martínez, Iris; Hernández-Camacho, Claudia J; Méndez-Rodríguez, Lía C; Zenteno-Savín, Tania

2016-01-01

In mammalian tissues under hypoxic conditions, ATP degradation results in accumulation of purine metabolites. During exercise, muscle energetic demand increases and oxygen consumption can exceed its supply. During breath-hold diving, oxygen supply is reduced and, although oxygen utilization is regulated by bradycardia (low heart rate) and peripheral vasoconstriction, tissues with low blood flow (ischemia) may become hypoxic. The goal of this study was to evaluate potential differences in the circulating levels of purine metabolism components between diving and exercise in bottlenose dolphins (Tursiops truncatus). Blood samples were taken from captive dolphins following a swimming routine (n=8) and after a 2min dive (n=8). Activity of enzymes involved in purine metabolism (hypoxanthine guanine phosphoribosyl transferase (HGPRT), inosine monophosphate deshydrogenase (IMPDH), xanthine oxidase (XO), purine nucleoside phosphorylase (PNP)), and purine metabolite (hypoxanthine (HX), xanthine (X), uric acid (UA), inosine monophosphate (IMP), inosine, nicotinamide adenine dinucleotide (NAD(+)), adenosine, adenosine monophosphate (AMP), adenosine diphosphate (ADP), ATP, guanosine diphosphate (GDP), guanosine triphosphate (GTP)) concentrations were quantified in erythrocyte and plasma samples. Enzymatic activity and purine metabolite concentrations involved in purine synthesis and degradation, were not significantly different between diving and exercise. Plasma adenosine concentration was higher after diving than exercise (p=0.03); this may be related to dive-induced ischemia. In erythrocytes, HGPRT activity was higher after diving than exercise (p=0.007), suggesting an increased capacity for purine recycling and ATP synthesis from IMP in ischemic tissues of bottlenose dolphins during diving. Purine recycling and physiological adaptations may maintain the ATP concentrations in bottlenose dolphins after diving and exercise. Copyright © 2015 Elsevier Inc. All rights reserved.

Enhanced activity of the purine nucleotide cycle of the exercising muscle in patients with hyperthyroidism.

PubMed

Fukui, H; Taniguchi , S; Ueta, Y; Yoshida, A; Ohtahara, A; Hisatome, I; Shigemasa, C

2001-05-01

Myopathy frequently develops in patients with hyperthyroidism, but its precise mechanism is not clearly understood. In this study we focused on the purine nucleotide cycle, which contributes to ATP balance in skeletal muscles. To investigate purine metabolism in muscles, we measured metabolites related to the purine nucleotide cycle using the semiischemic forearm test. We examined the following four groups: patients with untreated thyrotoxic Graves' disease (untreated group), patients with Graves' disease treated with methimazole (treated group), patients in remission (remission group), and healthy volunteers (control group). To trace the glycolytic process, we measured glycolytic metabolites (lactate and pyruvate) as well as purine metabolites (ammonia and hypoxanthine). In the untreated group, the levels of lactate, pyruvate, and ammonia released were remarkably higher than those in the control group. Hypoxanthine release also increased in the untreated group, but the difference among the patient groups was not statistically significant. The accelerated purine catabolism did not improve after 3 months of treatment with methimazole, but it was completely normalized in the remission group. This indicated that long-term maintenance of thyroid function was necessary for purine catabolism to recover. We presume that an unbalanced ATP supply or conversion of muscle fiber type may account for the acceleration of the purine nucleotide cycle under thyrotoxicosis. Such acceleration of the purine nucleotide cycle is thought to be in part a protective mechanism against a rapid collapse of the ATP energy balance in exercising muscles of patients with hyperthyroidism.

Plasma Hypoxanthine-Guanine Phosphoribosyl Transferase Activity in Bottlenose Dolphins Contributes to Avoiding Accumulation of Non-recyclable Purines

PubMed Central

López-Cruz, Roberto I.; Crocker, Daniel E.; Gaxiola-Robles, Ramón; Bernal, Jaime A.; Real-Valle, Roberto A.; Lugo-Lugo, Orlando; Zenteno-Savín, Tania

2016-01-01

Marine mammals are exposed to ischemia/reperfusion and hypoxia/reoxygenation during diving. During oxygen deprivation, adenosine triphosphate (ATP) breakdown implies purine metabolite accumulation, which in humans is associated with pathological conditions. Purine recycling in seals increases in response to prolonged fasting and ischemia. Concentrations of metabolites and activities of key enzymes in purine metabolism were examined in plasma and red blood cells from bottlenose dolphins (Tursiops truncatus) and humans. Hypoxanthine and inosine monophosphate concentrations were higher in plasma from dolphins than humans. Plasma hypoxanthine-guanine phosphoribosyl transferase (HGPRT) activity in dolphins suggests an elevated purine recycling rate, and a mechanism for avoiding accumulation of non-recyclable purines (xanthine and uric acid). Red blood cell concentrations of hypoxanthine, adenosine diphosphate, ATP and guanosine triphosphate were lower in dolphins than in humans; adenosine monophosphate and nicotinamide adenine dinucleotide concentrations were higher in dolphins. HGPRT activity in red blood cells was higher in humans than in dolphins. The lower concentrations of purine catabolism and recycling by-products in plasma from dolphins could be beneficial in providing substrates for recovery of ATP depleted during diving or vigorous swimming. These results suggest that purine salvage in dolphins could be a mechanism for delivering nucleotide precursors to tissues with high ATP and guanosine triphosphate requirements. PMID:27375492

Plasma Hypoxanthine-Guanine Phosphoribosyl Transferase Activity in Bottlenose Dolphins Contributes to Avoiding Accumulation of Non-recyclable Purines.

PubMed

López-Cruz, Roberto I; Crocker, Daniel E; Gaxiola-Robles, Ramón; Bernal, Jaime A; Real-Valle, Roberto A; Lugo-Lugo, Orlando; Zenteno-Savín, Tania

2016-01-01

Marine mammals are exposed to ischemia/reperfusion and hypoxia/reoxygenation during diving. During oxygen deprivation, adenosine triphosphate (ATP) breakdown implies purine metabolite accumulation, which in humans is associated with pathological conditions. Purine recycling in seals increases in response to prolonged fasting and ischemia. Concentrations of metabolites and activities of key enzymes in purine metabolism were examined in plasma and red blood cells from bottlenose dolphins (Tursiops truncatus) and humans. Hypoxanthine and inosine monophosphate concentrations were higher in plasma from dolphins than humans. Plasma hypoxanthine-guanine phosphoribosyl transferase (HGPRT) activity in dolphins suggests an elevated purine recycling rate, and a mechanism for avoiding accumulation of non-recyclable purines (xanthine and uric acid). Red blood cell concentrations of hypoxanthine, adenosine diphosphate, ATP and guanosine triphosphate were lower in dolphins than in humans; adenosine monophosphate and nicotinamide adenine dinucleotide concentrations were higher in dolphins. HGPRT activity in red blood cells was higher in humans than in dolphins. The lower concentrations of purine catabolism and recycling by-products in plasma from dolphins could be beneficial in providing substrates for recovery of ATP depleted during diving or vigorous swimming. These results suggest that purine salvage in dolphins could be a mechanism for delivering nucleotide precursors to tissues with high ATP and guanosine triphosphate requirements.

Purine biosynthesis is the bottleneck in trimethoprim-treated Bacillus subtilis.

PubMed

Stepanek, Jennifer Janina; Schäkermann, Sina; Wenzel, Michaela; Prochnow, Pascal; Bandow, Julia Elisabeth

2016-10-01

Trimethoprim is a folate biosynthesis inhibitor. Tetrahydrofolates are essential for the transfer of C 1 units in several biochemical pathways including purine, thymine, methionine, and glycine biosynthesis. This study addressed the effects of folate biosynthesis inhibition on bacterial physiology. Two complementary proteomic approaches were employed to analyze the response of Bacillus subtilis to trimethoprim. Acute changes in protein synthesis rates were monitored by radioactive pulse labeling of newly synthesized proteins and subsequent 2DE analysis. Changes in protein levels were detected using gel-free quantitative MS. Proteins involved in purine and histidine biosynthesis, the σ B -dependent general stress response, and sporulation were upregulated. Most prominently, the PurR-regulon required for de novo purine biosynthesis was derepressed indicating purine depletion. The general stress response was activated energy dependently and in a subpopulation of treated cultures an early onset of sporulation was observed, most likely triggered by low guanosine triphosphate levels. Supplementation of adenosine triphosphate, adenosine, and guanosine to the medium substantially decreased antibacterial activity, showing that purine depletion becomes the bottleneck in trimethoprim-treated B. subtilis. The frequently prescribed antibiotic trimethoprim causes purine depletion in B. subtilis, which can be complemented by supplementing purines to the medium. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Engineering a microbial platform for de novo biosynthesis of diverse methylxanthines

PubMed Central

McKeague, Maureen; Wang, Yen-Hsiang; Cravens, Aaron; Win, Maung Nyan; Smolke, Christina D.

2016-01-01

Engineered microbial biosynthesis of plant natural products can support manufacturing of complex bioactive molecules and enable discovery of non-naturally occurring derivatives. Purine alkaloids, including caffeine (coffee), theophylline (antiasthma drug), theobromine (chocolate), and other methylxanthines, play a significant role in pharmacology and food chemistry. Here, we engineered the eukaryotic microbial host Saccharomyces cerevisiae for the de novo biosynthesis of methylxanthines. We constructed a xanthine-to-xanthosine conversion pathway in native yeast central metabolism to increase endogenous purine flux for the production of 7-methylxanthine, a key intermediate in caffeine biosynthesis. Yeast strains were further engineered to produce caffeine through expression of several enzymes from the coffee plant. By expressing combinations of different N-methyltransferases, we were able to demonstrate re-direction of flux to an alternate pathway and develop strains that support the production of diverse methylxanthines. We achieved production of 270 μg/L, 61 μg/L, and 3700 μg/L of caffeine, theophylline, and 3-methylxanthine, respectively, in 0.3-L bench-scale batch fermentations. The constructed strains provide an early platform for de novo production of methylxanthines and with further development will advance the discovery and synthesis of xanthine derivatives. PMID:27519552

The plasma membrane permease PfNT1 is essential for purine salvage in the human malaria parasite Plasmodium falciparum.

PubMed

El Bissati, Kamal; Zufferey, Rachel; Witola, William H; Carter, Nicola S; Ullman, Buddy; Ben Mamoun, Choukri

2006-06-13

The human malaria parasite Plasmodium falciparum relies on the acquisition of host purines for its survival within human erythrocytes. Purine salvage by the parasite requires specialized transporters at the parasite plasma membrane (PPM), but the exact mechanism of purine entry into the infected erythrocyte, and the primary purine source used by the parasite, remain unknown. Here, we report that transgenic parasites lacking the PPM transporter PfNT1 (P. falciparum nucleoside transporter 1) are auxotrophic for hypoxanthine, inosine, and adenosine under physiological conditions and are viable only if these normally essential nutrients are provided at excess concentrations. Transport measurements across the PPM revealed a severe reduction in hypoxanthine uptake in the knockout, whereas adenosine and inosine transport were only partially affected. These data provide compelling evidence for a sequential pathway for exogenous purine conversion into hypoxanthine using host enzymes followed by PfNT1-mediated transport into the parasite. The phenotype of the conditionally lethal mutant establishes PfNT1 as a critical component of purine salvage in P. falciparum and validates PfNT1 as a potential therapeutic target.

Antinociceptive effect of purine nucleotides.

PubMed

Mello, C F; Begnini, J; De-La-Vega, D D; Lopes, F P; Schwartz, C C; Jimenez-Bernal, R E; Bellot, R G; Frussa-Filho, R

1996-10-01

The antinociceptive effect of purine nucleotides administered systematically (sc) was determined using the formalin and writhing tests in adult male albino mice. The mechanisms underlying nucleotide-induced antinociception were investigated by preinjecting the animals (sc) with specific antagonists for opioid (naloxone, 1 mg/kg), purinergic P1 (caffeine, 5, 10, of 30 mg/kg); theophylline, 10 mg/kg) or purinergic P2 receptors (suramin, 100 mg/kg; Coomassie blue, 30-300 mg/kg; quinidine, 10 mg/kg). Adenosine, adenosine monophosphate (AMP), diphosphate (ADP) and triphosphate (ATP) caused a reduction in the number of writhes and in the time of licking the formalin-injected paw. Naloxone had no effect on adenosine- or adenine nucleotide-induced antinociception. Caffeine (30 mg/kg) and theophylline (10 mg/kg) reversed the antinociceptive action of adenosine and adenine nucleotide derivatives in both tests. P2 antagonists did not reverse adenine nucleotide-induced antinociception. These results suggest that antinociceptive effect of adenine nucleotides is mediated by adenosine.

Development of Purine-Derived 18F-Labeled Pro-drug Tracers for Imaging of MRP1 Activity with PET

PubMed Central

2014-01-01

Multidrug resistance-associated protein 1 (MRP1) is a drug efflux transporter that has been implicated in the pathology of several neurological diseases and is associated with development of multidrug resistance. To enable measurement of MRP1 function in the living brain, a series of 6-halopurines decorated with fluorinated side chains have been synthesized and evaluated as putative pro-drug tracers. The tracers were designed to undergo conjugation with glutathione within the brain and hence form the corresponding MRP1 substrate tracers in situ. 6-Bromo-7-(2-[18F]fluoroethyl)purine showed good brain uptake and rapid metabolic conversion. Dynamic PET imaging demonstrated a marked difference in brain clearance rates between wild-type and mrp1 knockout mice, suggesting that the tracer can allow noninvasive assessment of MRP1 activity in vivo. PMID:24456310

An unusual mode of DNA duplex association: Watson-Crick interaction of all-purine deoxyribonucleic acids.

PubMed

Battersby, Thomas R; Albalos, Maria; Friesenhahn, Michel J

2007-05-01

Nucleic acid duplexes associating through purine-purine base pairing have been constructed and characterized in a remarkable demonstration of nucleic acids with mixed sequence and a natural backbone in an alternative duplex structure. The antiparallel deoxyribose all-purine duplexes associate specifically through Watson-Crick pairing, violating the nucleobase size-complementarity pairing convention found in Nature. Sequence-specific recognition displayed by these structures makes the duplexes suitable, in principle, for information storage and replication fundamental to molecular evolution in all living organisms. All-purine duplexes can be formed through association of purines found in natural ribonucleosides. Key to the formation of these duplexes is the N(3)-H tautomer of isoguanine, preferred in the duplex, but not in aqueous solution. The duplexes have relevance to evolution of the modern genetic code and can be used for molecular recognition of natural nucleic acids.

Hot shot induction and reperfusion with a specific blocker of the es-ENT1 nucleoside transporter before and after hypothermic cardioplegia abolishes myocardial stunning in acutely ischemic hearts despite metabolic derangement: Hot shot drug delivery before hypothermic cardioplegia

PubMed Central

Abd-Elfattah, Anwar Saad; Tuchy, Gert E.; Jessen, Michael E.; Salter, David R.; Goldstein, Jacques P.; Brunsting, Louis A.; Wechsler, Andrew S.

2013-01-01

Objective Simultaneous inhibition of the cardiac equilibrative-p-nitrobenzylthioinosine (NBMPR)–sensitive (es) type of the equilibrative nucleoside transport 1 (ENT1) nucleoside transporter, with NBMPR, and adenosine deaminase, with erythro-9-[2-hydroxy-3-nonyl]adenine (EHNA), prevents release of myocardial purines and attenuates myocardial stunning and fibrillation in canine models of warm ischemia and reperfusion. It is not known whether prolonged administration of hypothermic cardioplegia influences purine release and EHNA/NBMPR-mediated cardioprotection in acutely ischemic hearts. Methods Anesthetized dogs (n = 46), which underwent normothermic aortic crossclamping for 20 minutes on-pump, were divided to determine (1) purine release with induction of intermittent antegrade or continuous retrograde hypothermic cardioplegia and reperfusion, (2) the effects of postischemic treatment with 100 µM EHNA and 25 µM NBMPR on purine release and global functional recovery, and (3) whether a hot shot and reperfusion with EHNA/NBMPR inhibits purine release and attenuates ventricular dysfunction of ischemic hearts. Myocardial biopsies and coronary sinus effluents were obtained and analyzed using high-performance liquid chromatography. Results Warm ischemia depleted myocardial adenosine triphosphate and elevated purines (ie, inosine > adenosine) as markers of ischemia. Induction of intermittent antegrade or continuous retrograde hypothermic (4°C) cardioplegia releases purines until the heart becomes cold (<20°C). During reperfusion, the levels of hypoxanthine and xanthine (free radical substrates) were >90% of purines in coronary sinus effluent. Reperfusion with EHNA/NBMPR abolished ventricular dysfunction in acutely ischemic hearts with and without a hot shot and hypothermic cardioplegic arrest. Conclusions Induction of hypothermic cardioplegia releases purines from ischemic hearts until they become cold, whereas reperfusion induces massive purine release and myocardial stunning. Inhibition of cardiac es-ENT1 nucleoside transporter abolishes postischemic reperfusion injury in warm and cold cardiac surgery. PMID:23422047

Regulation of uric acid metabolism and excretion.

PubMed

Maiuolo, Jessica; Oppedisano, Francesca; Gratteri, Santo; Muscoli, Carolina; Mollace, Vincenzo

2016-06-15

Purines perform many important functions in the cell, being the formation of the monomeric precursors of nucleic acids DNA and RNA the most relevant one. Purines which also contribute to modulate energy metabolism and signal transduction, are structural components of some coenzymes and have been shown to play important roles in the physiology of platelets, muscles and neurotransmission. All cells require a balanced quantity of purines for growth, proliferation and survival. Under physiological conditions the enzymes involved in the purine metabolism maintain in the cell a balanced ratio between their synthesis and degradation. In humans the final compound of purines catabolism is uric acid. All other mammals possess the enzyme uricase that converts uric acid to allantoin that is easily eliminated through urine. Overproduction of uric acid, generated from the metabolism of purines, has been proven to play emerging roles in human disease. In fact the increase of serum uric acid is inversely associated with disease severity and especially with cardiovascular disease states. This review describes the enzymatic pathways involved in the degradation of purines, getting into their structure and biochemistry until the uric acid formation. Copyright © 2015. Published by Elsevier Ireland Ltd.

Ribonucleases 6 and 7 have antimicrobial function in the human and murine urinary tract

PubMed Central

Becknell, Brian; Eichler, Tad; Beceiro, Susana; Li, Birong; Easterling, Robert; Carpenter, Ashley R.; James, Cindy; McHugh, Kirk M.; Hains, David S.; Partida-Sanchez, Santiago; Spencer, John David

2014-01-01

Recent evidence suggests antimicrobial peptides protect the urinary tract from infection. Ribonuclease 7 (RNase 7), a member of the RNase A superfamily, is a potent epithelial-derived protein that maintains human urinary tract sterility. RNase 7 expression is restricted to primates, limiting evaluation of its antimicrobial activity in vivo. Here we identified Ribonuclease 6 (RNase 6) as the RNase A Superfamily member present in humans and mice that is most conserved at the amino acid level relative to RNase 7. Like RNase 7, recombinant human and murine RNase 6 has potent antimicrobial activity against uropathogens. Quantitative real-time PCR and immunoblot analysis indicate that RNase 6 mRNA and protein are up-regulated in the human and murine urinary tract during infection. Immunostaining located RNase 6 to resident and infiltrating monocytes, macrophages, and neutrophils. Uropathogenic E. coli induces RNase 6 peptide expression in human CD14+ monocytes and murine bone marrow derived macrophages. Thus, RNase 6 is an inducible, myeloid-derived protein with markedly different expression from the epithelial-derived RNase 7 but with equally potent antimicrobial activity. Our studies suggest RNase 6 serves as an evolutionarily conserved antimicrobial peptide that participates in the maintenance of urinary tract sterility. PMID:25075772

Comparative Biochemistry and Metabolism

DTIC Science & Technology

1978-12-01

pyrimidines). When interest includes labile pyrimidine derivatives, the DNA is hydrolyzed enzymatically; 5 mg DNA is dis- solved in water containing 20 j...Individual labeled pyrimidine nucleosides from animals so treated have been isolated but not yet identified. The DNA is hydrolyzed enzymatically to... hydrolyzed and chromatographically separated into pyrimidine oligonucleotides and free purine bases. At a dose of 60 mg hydrazine/kg body weight (LDO.0O

[Composition of 359 kidney stones from the East region of Algeria].

PubMed

Bouslama, S; Boutefnouchet, A; Hannache, B; Djemil, T; Kadi, A; Dahdouh, A; Saka, S; Daudon, M

2016-01-01

Determine stones composition of the upper urinary tract in the eastern region of Algeria. Our study focuses on a set of 359 stones of the upper urinary tract collected between January 2007 and December 2012 at hospitals in the eastern region of Algeria and analyzed by Fourier transform infrared spectroscopy. The male/female ratio was only 1.32. Calcium oxalate prevailed in 68.5% of stones and 49.3% of nuclei, mainly as whewellite (51.8% of stones and 37.9% of nuclei vs 16.7% and 11.4% respectively for weddellite). Carbapatite prevailed in 15% of stones and 29.8% of nuclei. The struvite, identified in 11.1% of calculi, prevailed in 3.9% of stones and 3.1% of nuclei. Among purines, uric acid prevailed with frequencies quite close to 8.9% and 7% respectively in the stone and in the nucleus while the ammonium urate prevailed in only 0.3% of stones and 3.3% of nuclei. The cystine frequency was 3.6% in both stone and nucleus. The frequency of stone with umbilication was 26.2%. Whewellite was the main component of umbilicated stones with Randall's plaque. Our results suggest that stones of the urinary tract in the Algerian east region resemble those observed in industrialized countries. Some features such as stones location, the whewellite prevalence, the frequencies of main components in both the stone and the nucleus as well as the formation of stones on renal papilla confirm this trend. 4. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Potential chemotherapeutic targets in the purine metabolism of parasites.

PubMed

el Kouni, Mahmoud H

2003-09-01

Parasites are responsible for a wide variety of infectious diseases in human as well as in domestic and wild animals, causing an enormous health and economical blight. Current containment strategies are not entirely successful and parasitic infections are on the rise. In the absence of availability of antiparasitic vaccines, chemotherapy remains the mainstay for the treatment of most parasitic diseases. However, there is an urgent need for new drugs to prevent or combat some major parasitic infections because of lack of a single effective approach for controlling the parasites (e.g., trypanosomiasis) or because some serious parasitic infections developed resistance to presently available drugs (e.g., malaria). The rational design of a drug is usually based on biochemical and physiological differences between pathogens and host. Some of the most striking differences between parasites and their mammalian host are found in purine metabolism. Purine nucleotides can be synthesized by the de novo and/or the so-called "salvage" pathways. Unlike their mammalian host, most parasites studied lack the pathways for de novo purine biosynthesis and rely on the salvage pathways to meet their purine demands. Moreover, because of the great phylogenic separation between the host and the parasite, there are in some cases sufficient distinctions between corresponding enzymes of the purine salvage from the host and the parasite that can be exploited to design specific inhibitors or "subversive substrates" for the parasitic enzymes. Furthermore, the specificities of purine transport, the first step in purine salvage, diverge significantly between parasites and their mammalian host. This review highlights the unique transporters and enzymes responsible for the salvage of purines in parasites that could constitute excellent potential targets for the design of safe and effective antiparasitic drugs.

Recognition of Artificial Nucleobases by E. coli Purine Nucleoside Phosphorylase versus its Ser90Ala Mutant in the Synthesis of Base-Modified Nucleosides.

PubMed

Fateev, Ilja V; Kharitonova, Maria I; Antonov, Konstantin V; Konstantinova, Irina D; Stepanenko, Vasily N; Esipov, Roman S; Seela, Frank; Temburnikar, Kartik W; Seley-Radtke, Katherine L; Stepchenko, Vladimir A; Sokolov, Yuri A; Miroshnikov, Anatoly I; Mikhailopulo, Igor A

2015-09-14

A wide range of natural purine analogues was used as probe to assess the mechanism of recognition by the wild-type (WT) E. coli purine nucleoside phosphorylase (PNP) versus its Ser90Ala mutant. The results were analyzed from viewpoint of the role of the Ser90 residue and the structural features of the bases. It was found that the Ser90 residue of the PNP 1) plays an important role in the binding and activation of 8-aza-7-deazapurines in the synthesis of their nucleosides, 2) participates in the binding of α-D-pentofuranose-1-phosphates at the catalytic site of the PNP, and 3) catalyzes the dephosphorylation of intermediary formed 2-deoxy-α-D-ribofuranose-1-phosphate in the trans-2-deoxyribosylation reaction. 5-Aza-7-deazaguanine manifested excellent substrate activity for both enzymes, 8-amino-7-thiaguanine and 2-aminobenzothiazole showed no substrate activity for both enzymes. On the contrary, the 2-amino derivatives of benzimidazole and benzoxazole are substrates and are converted into the N1- and unusual N2-glycosides, respectively. 9-Deaza-5-iodoxanthine showed moderate inhibitory activity of the WT E. coli PNP, whereas 9-deazaxanthine and its 2'-deoxyriboside are weak inhibitors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Purine inhibitors of protein kinases, G proteins and polymerases

DOEpatents

Gray, Nathanael S.; Schultz, Peter; Kim, Sung-Hou; Meijer, Laurent

2001-07-03

The present invention relates to purine analogs that inhibit, inter alia, protein kinases, G-proteins and polymerases. In addition, the present invention relates to methods of using such purine analogs to inhibit protein kinases, G-proteins, polymerases and other cellular processes and to treat cellular proliferative diseases.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meadows, J.; Smith, R.C.

Uric acid has been proposed to be an important antioxidant and free radical scavenger in humans. Of the purine and pyrimidine compounds examined in this study, uric acid showed the greatest susceptibility to ozone-induced degradation. The parent compounds, purine and pyrimidine, were more resistant to ozonation than were the nucleobases. When the degradation of OH-substituted purines was examined, it was found that the more OH groups on the purine ring, the more readily the purine was degraded. Urea and allantoin were identified as degradation products of uric acid. The relative rates of nucleobase degradation in the presence and absence ofmore » uric acid were compared. Uric acid protected thymine, guanine, and uracil from degradation by ozone. In this system uric acid was found to protect the nucleobases as effectively as reduced glutathione.« less

Dietary purines in vegetarian meat analogues.

PubMed

Havlik, Jaroslav; Plachy, Vladimir; Fernandez, Javier; Rada, Vojtech

2010-11-01

The meat alternatives market offers a wide range of products resembling meat in taste, flavour or texture but based on vegetable protein sources. These high protein-low purine foods may find application in a low purine or purine-free diet, which is sometimes suggested for subjects with increased serum urate levels, i.e. hyperuricaemia. We determined purine content (uric acid, adenine, guanine, hypoxanthine, xanthine) in 39 commercially available meat substitutes and evaluated them in relation to their protein content. Some of the products contained a comparable sum of adenine and hypoxanthine per protein as meat. Analysis of variance showed an influence of protein source used. Mycoprotein-based products had significantly higher contents (2264 mg kg(-1)) of adenine and hypoxanthine per kg of 100% protein than soybean-based products (1648 mg kg(-1)) or mixtures consisting of soybean protein and wheat protein (1239 mg kg(-1)). Protein-rich vegetable-based meat substitutes might be generally accepted as meat alternatives for individuals on special diets. The type of protein used to manufacture these products determines the total content of purines, which is relatively higher in the case of mycoprotein or soybean protein, while appearing lower in wheat protein and egg white-based products. These are therefore more suitable for dietary considerations in a low-purine diet for hyperuricaemic subjects. 2010 Society of Chemical Industry

Effects of day of gestation and feeding regimen in Holstein × Gyr cows: I. Apparent total-tract digestibility, nitrogen balance, and fat deposition.

PubMed

Rotta, P P; Filho, S C Valadares; Gionbelli, T R S; Costa E Silva, L F; Engle, T E; Marcondes, M I; Machado, F S; Villadiego, F A C; Silva, L H R

2015-05-01

This study investigated how feeding regimen (FR) alters apparent total-tract digestibility, performance, N balance, excretion of purine derivatives, and fat deposition in Holstein × Gyr cows at different days of gestation (DG). Forty-four pregnant multiparous Holstein × Gyr cows with an average initial body weight of 480±10.1 kg and an initial age of 5±0.5 yr old were allocated to 1 of 2 FR: ad libitum (AL; n=20) and maintenance level (ML; n=24). Maintenance level was considered to be 1.15% of body weight on a dry matter (DM) basis and met 100% of the energy requirements, whereas AL provided 190% of total net energy requirements. Data for hot and cold carcass dressing, fat deposition, average daily gain, empty body gain, and average daily gain without the gravid uterus were analyzed as a 4×2 factorial design. Intake, apparent total-tract digestibility, N balance, urinary concentration of urea, and purine derivatives data were analyzed as repeated measurements taken over the 28-d period (122, 150, 178, 206, 234, and 262 d of gestation). Cows were individually fed a corn silage-concentrate based diet composed of 93% roughage and 7% concentrate (DM basis) as a total mixed ration. Pregnant cows were slaughtered on 4 different DG: 139 (n=11), 199 (n=11), 241 (n=11), and 268 d (n=11). Overall, DM intake decreased as DG increased. This decrease observed in DM intake may be associated with the reduction in ruminal volume caused by the rapid increase in fetal size during late gestation. We observed an interaction for DM and organic matter apparent total-tract digestibility between FR and DG; at 150, 178, and 206 d of gestation, ML-fed cows had greater DM and organic matter apparent total-tract digestibility values than AL-fed cows. Rib fat thickness, mesentery, and kidney, pelvic, and heart fat were greater in AL-fed than in ML-fed cows at all DG, with the exception of rib fat thickness on d 139. Ad libitum-fed cows excreted more N in their feces and urine compared with ML-fed cows. Pregnant cows that were fed at maintenance had greater digestibility during some DG, excreted less N in feces and less N and urea in urine, and deposited less fat in the body. We therefore recommend ML (1.15% of body weight with 93% of roughage) as a FR for pregnant dry cows; however, during the last month of gestation, AL seems to be the most appropriate FR to avoid loss of body weight. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Functional and Structural Characterization of Purine Nucleoside Phosphorylase from Kluyveromyces lactis and Its Potential Applications in Reducing Purine Content in Food

PubMed Central

Mahor, Durga; Priyanka, Anu; Prasad, Gandham S; Thakur, Krishan Gopal

2016-01-01

Consumption of foods and beverages with high purine content increases the risk of hyperuricemia, which causes gout and can lead to cardiovascular, renal, and other metabolic disorders. As patients often find dietary restrictions challenging, enzymatically lowering purine content in popular foods and beverages offers a safe and attractive strategy to control hyperuricemia. Here, we report structurally and functionally characterized purine nucleoside phosphorylase (PNP) from Kluyveromyces lactis (KlacPNP), a key enzyme involved in the purine degradation pathway. We report a 1.97 Å resolution crystal structure of homotrimeric KlacPNP with an intrinsically bound hypoxanthine in the active site. KlacPNP belongs to the nucleoside phosphorylase-I (NP-I) family, and it specifically utilizes 6-oxopurine substrates in the following order: inosine > guanosine > xanthosine, but is inactive towards adenosine. To engineer enzymes with broad substrate specificity, we created two point variants, KlacPNPN256D and KlacPNPN256E, by replacing the catalytically active Asn256 with Asp and Glu, respectively, based on structural and comparative sequence analysis. KlacPNPN256D not only displayed broad substrate specificity by utilizing both 6-oxopurines and 6-aminopurines in the order adenosine > inosine > xanthosine > guanosine, but also displayed reversal of substrate specificity. In contrast, KlacPNPN256E was highly specific to inosine and could not utilize other tested substrates. Beer consumption is associated with increased risk of developing gout, owing to its high purine content. Here, we demonstrate that KlacPNP and KlacPNPN256D could be used to catalyze a key reaction involved in lowering beer purine content. Biochemical properties of these enzymes such as activity across a wide pH range, optimum activity at about 25°C, and stability for months at about 8°C, make them suitable candidates for food and beverage industries. Since KlacPNPN256D has broad substrate specificity, a combination of engineered KlacPNP and other enzymes involved in purine degradation could effectively lower the purine content in foods and beverages. PMID:27768715

Dynamic architecture of the purinosome involved in human de novo purine biosynthesis.

PubMed

Kyoung, Minjoung; Russell, Sarah J; Kohnhorst, Casey L; Esemoto, Nopondo N; An, Songon

2015-01-27

Enzymes in human de novo purine biosynthesis have been demonstrated to form a reversible, transient multienzyme complex, the purinosome, upon purine starvation. However, characterization of purinosomes has been limited to HeLa cells and has heavily relied on qualitative examination of their subcellular localization and reversibility under wide-field fluorescence microscopy. Quantitative approaches, which are particularly compatible with human disease-relevant cell lines, are necessary to explicitly understand the purinosome in live cells. In this work, human breast carcinoma Hs578T cells have been utilized to demonstrate the preferential utilization of the purinosome under purine-depleted conditions. In addition, we have employed a confocal microscopy-based biophysical technique, fluorescence recovery after photobleaching, to characterize kinetic properties of the purinosome in live Hs578T cells. Quantitative characterization of the diffusion coefficients of all de novo purine biosynthetic enzymes reveals the significant reduction of their mobile kinetics upon purinosome formation, the dynamic partitioning of each enzyme into the purinosome, and the existence of three intermediate species in purinosome assembly under purine starvation. We also demonstrate that the diffusion coefficient of the purine salvage enzyme, hypoxanthine phosphoribosyltransferase 1, is not sensitive to purine starvation, indicating exclusion of the salvage pathway from the purinosome. Furthermore, our biophysical characterization of nonmetabolic enzymes clarifies that purinosomes are spatiotemporally different cellular bodies from stress granules and cytoplasmic protein aggregates in both Hs578T and HeLa cells. Collectively, quantitative analyses of the purinosome in Hs578T cells led us to provide novel insights for the dynamic architecture of the purinosome assembly.

Determination of purine contents in different parts of pork and beef by high performance liquid chromatography.

PubMed

Rong, Shengzhong; Zou, Lina; Zhang, Yannan; Zhang, Guangteng; Li, Xiaoxia; Li, Miaojing; Yang, Fenghua; Li, Chunmei; He, Yingjuan; Guan, Hongjun; Guo, Yupeng; Wang, Dong; Cui, Xinyu; Ye, Hongting; Liu, Fenghai; Pan, Hongzhi; Yang, Yuexin

2015-03-01

Determination of adenine, hypoxanthine, guanine and xanthine in different parts of pork and beef using high performance liquid chromatography was described. Chromatographic separation was carried out on Waters Atlantis T3 column (4.6 mm × 250 mm × 5 μm) with column temperature at 30 °C. The mobile phase contained 99% 10.0 mmol/L ammonium formate solution at pH 3.6 and 1.0% methanol. Chromatography was achieved at a flow rate of 1.0 mL/min and detection wavelength at 254 nm. The results indicated that total purine amounts in pork rump and beef sirloin were higher than those in other parts (P<0.05). The principal purine bases were hypoxanthine and adenine, and hypoxanthine content was the most highest in all samples (P<0.05). As pork rump and beef sirloin contain considerable amounts of total purine and uricogenic purine base, we suggest that excess consumption of them be avoid, whereas pork loin chop and beef rib eye are more suitable for a low-purine diet. Copyright © 2014 Elsevier Ltd. All rights reserved.

Structural Determinants of the 5′-Methylthioinosine Specificity of Plasmodium Purine Nucleoside Phosphorylase

PubMed Central

Donaldson, Teraya M.; Ting, Li-Min; Zhan, Chenyang; Shi, Wuxian; Zheng, Renjian; Almo, Steven C.; Kim, Kami

2014-01-01

Plasmodium parasites rely upon purine salvage for survival. Plasmodium purine nucleoside phosphorylase is part of the streamlined Plasmodium purine salvage pathway that leads to the phosphorylysis of both purines and 5′-methylthiopurines, byproducts of polyamine synthesis. We have explored structural features in Plasmodium falciparum purine nucleoside phosphorylase (PfPNP) that affect efficiency of catalysis as well as those that make it suitable for dual specificity. We used site directed mutagenesis to identify residues critical for PfPNP catalytic activity as well as critical residues within a hydrophobic pocket required for accommodation of the 5′-methylthio group. Kinetic analysis data shows that several mutants had disrupted binding of the 5′-methylthio group while retaining activity for inosine. A triple PfPNP mutant that mimics Toxoplasma gondii PNP had significant loss of 5′-methylthio activity with retention of inosine activity. Crystallographic investigation of the triple mutant PfPNP with Tyr160Phe, Val66Ile, andVal73Ile in complex with the transition state inhibitor immucillin H reveals fewer hydrogen bond interactions for the inhibitor in the hydrophobic pocket. PMID:24416224

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Hongxing; Xiao, Hailong; Lu, Zhenmei, E-mail: lzhenmei@zju.edu.cn

4-Epi-oxytetracycline (4-EOTC), one of main oxytetracycline (OTC) metabolites, can be commonly detected in food and environment. The toxicity and effects of OTC on animals have been well characterized; however, its metabolites have never been studied systemically. This study aims to investigate 15-day oral dose toxicity and urine metabonomics changes of 4-EOTC after repeated administration in Wistar rats at daily doses of 0.5, 5.0 and 50.0 mg/kg bw (bodyweight). Hematology and clinical chemistry parameters, including white blood cell count, red blood cell count, total protein, globulin and albumin/globulin, were obviously altered in rats of 5.0 and 50.0 mg/kg bw. Histopathology changesmore » of kidney and liver tissues were also observed in high-dose groups. Urinary metabolites from all groups were analyzed using ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). Seventeen metabolites contributing to the clusters were identified as potential biomarkers from multivariate analysis, including aminoadipic acid, 6-phosphogluconate, sebacic acid, pipecolic acid, etc. The significant changes of these biomarkers demonstrated metabonomic variations in treated rats, especially lysine and purine metabolism. For the first time in this paper, we combined the results of toxicity and metabonomics induced by 4-EOTC for the serious reconsideration of the safety and potential risks of antibiotics and its degradation metabolites. - Highlights: • 4-Epioxytetracycline (4-EOTC) induced damages in liver and kidney. • Metabonomics changes especially amino acid and purine metabolism were observed. • Security of OTC metabolite 4-EOTC should be taken into serious reconsideration.« less

Regulation of Purine Metabolism in Intact Leaves of Coffea arabica.

PubMed

Nazario, G. M.; Lovatt, C. J.

1993-12-01

The capacity of Coffea arabica leaves (5- x 5-mm pieces) to synthesize de novo and catabolize purine nucleotides to provide precursors for caffeine (1,3,7-trimethylxanthine) was investigated. Consistent with de novo synthesis, glycine, bicarbonate, and formate were incorporated into the purine ring of inosine 5[prime]-monophosphate (IMP) and adenine nucleotides ([sigma]Ade); azaserine, a known inhibitor of purine de novo synthesis, inhibited incorporation. Activity of the de novo pathway in C. arabica per g fresh weight of leaf tissue during a 3-h incubation period was 8 [plus or minus] 4 nmol of formate incorporated into IMP, 61 [plus or minus] 7 nmol into [sigma]Ade, and 150 nmol into caffeine (the latter during a 7-h incubation). Coffee leaves exhibited classical purine catabolism. Radiolabeled formate, inosine, adenosine, and adenine were incorporated into hypoxanthine and xanthine, which were catabolized to allantoin and urea. Urease activity was demonstrated. Per g fresh weight, coffee leaf squares incorporated 90 [plus or minus] 22 nmol of xanthine into caffeine in 7 h but degraded 102 [plus or minus] 1 nmol of xanthine to allantoin in 3 h. Feedback control of de novo purine biosynthesis was contrasted in C. arabica and Cucurbita pepo, a species that does not synthesize purine alkaloids. End-product inhibition was demonstrated to occur in both species but at different enzyme reactions.

Discovery of Novel Bruton's Tyrosine Kinase (BTK) Inhibitors Bearing a N,9-Diphenyl-9H-purin-2-amine Scaffold.

PubMed

Ge, Yang; Jin, Yue; Wang, Changyuan; Zhang, Jianbin; Tang, Zeyao; Peng, Jinyong; Liu, Kexin; Li, Yanxia; Zhou, Youwen; Ma, Xiaodong

2016-12-08

Based on the pyrimidine skeleton of EGFR T790M inhibitors, a series of N ,9-diphenyl-9 H -purin-2-amine derivatives were identified as effective BTK inhibitors. Among these compounds, inhibitors 10d , 10i , and 10j , possessing IC 50 values of 0.5, 0.5, and 0.4 nM, displayed anti-BTK kinase activity that was as potent as the reference compounds. In particular, compound 10j suppressed the proliferation of two typical B-cell leukemia cell lines expressing high levels of BTK with concentrations of 7.75 and 12.6 μM. The activity of the subject compound as determined by the CCK-8 method and apoptosis analysis validated that inhibitor 1 0j is slightly more potent than AVL-292 and ibrutinib. The results of these experimental explorations suggested that 10j could serve as a valuable molecule for control of leukemia pending further developments.

Recognition of the bacterial alarmone ZMP through long-distance association of two RNA subdomains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, Christopher P.; Ferré-D'Amaré, Adrian R.

The bacterial alarmone 5-aminoimidazole-4-carboxamide riboside 5'-triphosphate (AICAR triphosphate or ZTP), derived from the monophosphorylated purine precursor ZMP, accumulates during folate starvation. ZTP regulates genes involved in purine and folate metabolism through a cognate riboswitch. The linker connecting this riboswitch's two subdomains varies in length by over 100 nucleotides. In this paper, we report the cocrystal structure of the Fusobacterium ulcerans riboswitch bound to ZMP, which spans the two subdomains whose interface also comprises a pseudoknot and ribose zipper. The riboswitch recognizes the carboxamide oxygen of ZMP through an unprecedented inner-sphere coordination with a Mg 2+ ion. We show that themore » affinity of the riboswitch for ZMP is modulated by the linker length. Notably, ZMP can simultaneously bind to the two subdomains even when they are synthesized as separate RNAs. Finally, the ZTP riboswitch demonstrates how specific small-molecule binding can drive association of distant noncoding-RNA domains to regulate gene expression.« less

Inhibition by 6-mercaptopurine of purine phosphoribosyltransferases from Ehrlich ascites-tumour cells that are resistant to this drug

PubMed Central

Atkinson, M. R.; Murray, A. W.

1965-01-01

1. A strain of Ehrlich ascites-tumour cells that showed little inhibition of growth in the presence of 6-mercaptopurine accumulated less than 5% as much 6-thioinosine 5′-phosphate in vivo, in the presence of 6-mercaptopurine, as did the sensitive strain from which it was derived. 2. Specific activities of the phosphoribosyltransferases that convert adenine, guanine, hypoxanthine and 6-mercaptopurine into AMP, GMP, IMP and 6-thioinosine 5′-phosphate were similar in extracts of the resistant and the sensitive cells. 3. As found previously with sensitive cells, 6-mercaptopurine is a competitive inhibitor of guanine phosphoribosyltransferase and hypoxanthine phosphoribosyltransferase from the resistant cells and does not inhibit the adenine phosphoribosyltransferase from these cells. Michaelis constants and inhibitor constants of the purine phosphoribosyltransferases from resistant cells did not differ significantly from those measured with the corresponding enzymes from sensitive cells. 4. Resistance to 6-mercaptopurine in this case is probably not due to qualitative or quantitative changes in these transferases. PMID:14342251

Recognition of the bacterial alarmone ZMP through long-distance association of two RNA subdomains

DOE PAGES

Jones, Christopher P.; Ferré-D'Amaré, Adrian R.

2015-08-17

The bacterial alarmone 5-aminoimidazole-4-carboxamide riboside 5'-triphosphate (AICAR triphosphate or ZTP), derived from the monophosphorylated purine precursor ZMP, accumulates during folate starvation. ZTP regulates genes involved in purine and folate metabolism through a cognate riboswitch. The linker connecting this riboswitch's two subdomains varies in length by over 100 nucleotides. In this paper, we report the cocrystal structure of the Fusobacterium ulcerans riboswitch bound to ZMP, which spans the two subdomains whose interface also comprises a pseudoknot and ribose zipper. The riboswitch recognizes the carboxamide oxygen of ZMP through an unprecedented inner-sphere coordination with a Mg 2+ ion. We show that themore » affinity of the riboswitch for ZMP is modulated by the linker length. Notably, ZMP can simultaneously bind to the two subdomains even when they are synthesized as separate RNAs. Finally, the ZTP riboswitch demonstrates how specific small-molecule binding can drive association of distant noncoding-RNA domains to regulate gene expression.« less

Pediatric neurological syndromes and inborn errors of purine metabolism.

PubMed

Camici, Marcella; Micheli, Vanna; Ipata, Piero Luigi; Tozzi, Maria Grazia

2010-02-01

This review is devised to gather the presently known inborn errors of purine metabolism that manifest neurological pediatric syndromes. The aim is to draw a comprehensive picture of these rare diseases, characterized by unexpected and often devastating neurological symptoms. Although investigated for many years, most purine metabolism disorders associated to psychomotor dysfunctions still hide the molecular link between the metabolic derangement and the neurological manifestations. This basically indicates that many of the actual functions of nucleosides and nucleotides in the development and function of several organs, in particular central nervous system, are still unknown. Both superactivity and deficiency of phosphoribosylpyrophosphate synthetase cause hereditary disorders characterized, in most cases, by neurological impairments. The deficiency of adenylosuccinate lyase and 5-amino-4-imidazolecarboxamide ribotide transformylase/IMP cyclohydrolase, both belonging to the de novo purine synthesis pathway, is also associated to severe neurological manifestations. Among catabolic enzymes, hyperactivity of ectosolic 5'-nucleotidase, as well as deficiency of purine nucleoside phosphorylase and adenosine deaminase also lead to syndromes affecting the central nervous system. The most severe pathologies are associated to the deficiency of the salvage pathway enzymes hypoxanthine-guanine phosphoribosyltransferase and deoxyguanosine kinase: the former due to an unexplained adverse effect exerted on the development and/or differentiation of dopaminergic neurons, the latter due to a clear impairment of mitochondrial functions. The assessment of hypo- or hyperuricemic conditions is suggestive of purine enzyme dysfunctions, but most disorders of purine metabolism may escape the clinical investigation because they are not associated to these metabolic derangements. This review may represent a starting point stimulating both scientists and physicians involved in the study of neurological dysfunctions caused by inborn errors of purine metabolism with the aim to find novel therapeutical approaches. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Acyclic Immucillin Phosphonates. Second-Generation Inhibitors of Plasmodium falciparum Hypoxanthine- Guanine-Xanthine Phosphoribosyltransferase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hazelton, Keith Z.; Ho, Meng-Chaio; Cassera, Maria B.

We found that Plasmodium falciparum is the primary cause of deaths from malaria. It is a purine auxotroph and relies on hypoxanthine salvage from the host purine pool. Purine starvation as an antimalarial target has been validated by inhibition of purine nucleoside phosphorylase. Hypoxanthine depletion kills Plasmodium falciparum in cell culture and in Aotus monkey infections. Hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGXPRT) from P. falciparum is required for hypoxanthine salvage by forming inosine 5'-monophosphate, a branchpoint for all purine nucleotide synthesis in the parasite. We present a class of HGXPRT inhibitors, the acyclic immucillin phosphonates (AIPs), and cell permeable AIP prodrugs. The AIPsmore » are simple, potent, selective, and biologically stable inhibitors. The AIP prodrugs block proliferation of cultured parasites by inhibiting the incorporation of hypoxanthine into the parasite nucleotide pool and validates HGXPRT as a target in malaria.« less

Urinary metabonomics elucidate the therapeutic mechanism of Orthosiphon stamineus in mouse crystal-induced kidney injury.

PubMed

Gao, Songyan; Chen, Wei; Peng, Zhongjiang; Li, Na; Su, Li; Lv, Diya; Li, Ling; Lin, Qishan; Dong, Xin; Guo, Zhiyong; Lou, Ziyang

2015-05-26

Orthosiphon stamineus (OS), a traditional Chinese herb, is often used for promoting urination and treating nephrolithiasis. Urolithiasis is a major worldwide public health burden due to its high incidence of recurrence and damage to renal function. However, the etiology for urolithiasis is not well understood. Metabonomics, the systematic study of small molecule metabolites present in biological samples, has become a valid and powerful tool for understanding disease phenotypes. In this study, a urinary metabolic profiling analysis was performed in a mouse model of renal calcium oxalate crystal deposition to identify potential biomarkers for crystal-induced renal damage and the anti-crystal mechanism of OS. Thirty six mice were randomly divided into six groups including Saline, Crystal, Cystone and OS at dosages of 0.5g/kg, 1g/kg, and 2g/kg. A metabonomics approach using ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) was developed to perform the urinary metabolic profiling analysis. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were utilized to identify differences between the metabolic profiles of mice in the saline control group and crystal group. Using partial least squares-discriminant analysis, 30 metabolites were identified as potential biomarkers of crystal-induced renal damage. Most of them were primarily involved in amino acid metabolism, taurine and hypotaurine metabolism, purine metabolism, and the citrate cycle (TCA). After the treatment with OS, the levels of 20 biomarkers had returned to the levels of the control samples. Our results suggest that OS has a protective effect for mice with crystal-induced kidney injury via the regulation of multiple metabolic pathways primarily involving amino acid, energy and choline metabolism. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Raman Spectroscopy of the Interferon-Induced 2’,5’-Oligoadenylates

DTIC Science & Technology

1987-06-25

generation of the Raman spectrum of triethyl ammonium ion ••••••••••••••••••••••••••••••• 41 12. structures of purine, adenine, purine riboside , adenosine...ribose 5 1-phosphate, AMP, and ATP........ 48 13. Raman spectra of adenine and purine •••••••.••••••••• 49 14. Raman spectra of purine riboside and... nicotinamide adenine dinucleotide; TFAB, triethyl anunonium bicarbonate; TFA, triethyl amm::mium. ion; CD circular _dichroism; NMR, nuclear magnetic

Purine nucleoside phosphorylase and xanthine oxidase activities in erythrocytes and plasma from marine, semiaquatic and terrestrial mammals.

PubMed

López-Cruz, Roberto I; Pérez-Milicua, Myrna Barjau; Crocker, Daniel E; Gaxiola-Robles, Ramón; Bernal-Vertiz, Jaime A; de la Rosa, Alejandro; Vázquez-Medina, José P; Zenteno-Savín, Tania

2014-05-01

Purine nucleoside phosphorylase (PNP) and xanthine oxidase (XO) are key enzymes involved in the purine salvage pathway. PNP metabolizes purine bases to synthetize purine nucleotides whereas XO catalyzes the oxidation of purines to uric acid. In humans, PNP activity is reported to be high in erythrocytes and XO activity to be low in plasma; however, XO activity increases after ischemic events. XO activity in plasma of northern elephant seals has been reported during prolonged fasting and rest and voluntary associated apneas. The objective of this study was to analyze circulating PNP and XO activities in marine mammals adapted to tolerate repeated cycles of ischemia/reperfusion associated with diving (bottlenose dolphin, northern elephant seal) in comparison with semiaquatic (river otter) and terrestrial mammals (human, pig). PNP activities in plasma and erythrocytes, as well as XO activity in plasma, from all species were quantified by spectrophotometry. No clear relationship in circulating PNP or XO activity could be established between marine, semiaquatic and terrestrial mammals. Erythrocytes from bottlenose dolphins and humans are highly permeable to nucleosides and glucose, intraerythrocyte PNP activity may be related to a release of purine nucleotides from the liver. High-energy costs will probably mean a higher ATP degradation rate in river otters, as compared to northern elephant seals or dolphins. Lower erythrocyte PNP activity and elevated plasma XO activity in northern elephant seal could be associated with fasting and/or sleep- and dive-associated apneas. Copyright © 2014 Elsevier Inc. All rights reserved.

Purine salvage in the apicomplexan Sarcocystis neurona, and generation of hypoxanthine-xanthine-guanine phosphoribosyltransferase-deficient clones for positive-negative selection of transgenic parasites.

PubMed

Dangoudoubiyam, Sriveny; Zhang, Zijing; Howe, Daniel K

2014-09-01

Sarcocystis neurona is an apicomplexan parasite that causes severe neurological disease in horses and marine mammals. The Apicomplexa are all obligate intracellular parasites that lack purine biosynthesis pathways and rely on the host cell for their purine requirements. Hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) and adenosine kinase (AK) are key enzymes that function in two complementary purine salvage pathways in apicomplexans. Bioinformatic searches of the S. neurona genome revealed genes encoding HXGPRT, AK and all of the major purine salvage enzymes except purine nucleoside phosphorylase. Wild-type S. neurona were able to grow in the presence of mycophenolic acid (MPA) but were inhibited by 6-thioxanthine (6-TX), suggesting that the pathways involving either HXGPRT or AK are functional in this parasite. Prior work with Toxoplasma gondii demonstrated the utility of HXGPRT as a positive-negative selection marker. To enable the use of HXGPRT in S. neurona, the SnHXGPRT gene sequence was determined and a gene-targeting plasmid was transfected into S. neurona. SnHXGPRT-deficient mutants were selected with 6-TX, and single-cell clones were obtained. These Sn∆HXG parasites were susceptible to MPA and could be complemented using the heterologous T. gondii HXGPRT gene. In summary, S. neurona possesses both purine salvage pathways described in apicomplexans, thus allowing the use of HXGPRT as a positive-negative drug selection marker in this parasite.

Genetic evidence for the essential role of PfNT1 in the transport and utilization of xanthine, guanine, guanosine and adenine by Plasmodium falciparum.

PubMed

El Bissati, Kamal; Downie, Megan J; Kim, Seong-Kyoun; Horowitz, Michael; Carter, Nicola; Ullman, Buddy; Ben Mamoun, Choukri

2008-10-01

The malaria parasite, Plasmodium falciparum, is unable to synthesize the purine ring de novo and is therefore wholly dependent upon purine salvage from the host for survival. Previous studies have indicated that a P. falciparum strain in which the purine transporter PfNT1 had been disrupted was unable to grow on physiological concentrations of adenosine, inosine and hypoxanthine. We have now used an episomally complemented pfnt1Delta knockout parasite strain to confirm genetically the functional role of PfNT1 in P. falciparum purine uptake and utilization. Episomal complementation by PfNT1 restored the ability of pfnt1Delta parasites to transport and utilize adenosine, inosine and hypoxanthine as purine sources. The ability of wild-type and pfnt1Delta knockout parasites to transport and utilize the other physiologically relevant purines adenine, guanine, guanosine and xanthine was also examined. Unlike wild-type and complemented P. falciparum parasites, pfnt1Delta parasites could not proliferate on guanine, guanosine or xanthine as purine sources, and no significant transport of these substrates could be detected in isolated parasites. Interestingly, whereas isolated pfnt1Delta parasites were still capable of adenine transport, these parasites grew only when adenine was provided at high, non-physiological concentrations. Taken together these results demonstrate that, in addition to hypoxanthine, inosine and adenosine, PfNT1 is essential for the transport and utilization of xanthine, guanine and guanosine.

Prebiotic chemistry and nucleic acid replication

NASA Technical Reports Server (NTRS)

Orgel, L. E.; Lohrmann, R.

1974-01-01

Recent work is reviewed on some reactions that could have occurred on the primitive earth and that could have played a part in the evolution of a self-replicating system. The transition from the primitive atmosphere to the simplest replicating molecules is considered in four stages: (1) the formation of a 'prebiotic soup' of organic precursors, including the purine and pyrimidine bases and the pentose sugars; (2) the condensation of these precursors and inorganic phosphate to form monomeric nucleotides and activated nucleotide derivatives; (3) the polymerization of nucleotide derivatives to oligonucleotides; and (4) the complementary replication of oligonucleotides in a template-directed process that depends on Watson-Crick base pairing.

Effects of AIT-082, a purine derivative, on tremor induced by arecoline or oxotremorine in mice.

PubMed

Nannan, Gao; Runmei, Yang; Fusheng, Lin; Shoulan, Zhang; Guangqing, Lei

2007-01-01

The effects of AIT-082, a hypoxanthine derivative, on tremor in mice were investigated. The mice received intragastric administration of AIT-082 for consecutive 60 days at doses of 150, 300 and 600 mg.kg(-1). The results showed that AIT-082 not only effectively inhibited the tremor induced by arecoline or oxotremorine, but also alleviated the tremor intensity and significantly shortened the tremor durations. The inhibition of tremor was perhaps associated with the central cholinergic nerve depressant effects as well as the stimulation of proliferation and differentiation of nerve cells. Copyright (c) 2007 S. Karger AG, Basel.

Platelet-derived growth factor receptor beta: a novel urinary biomarker for recurrence of non-muscle-invasive bladder cancer.

PubMed

Feng, Jiayu; He, Weifeng; Song, Yajun; Wang, Ying; Simpson, Richard J; Zhang, Xiaorong; Luo, Gaoxing; Wu, Jun; Huang, Chibing

2014-01-01

Non-muscle-invasive bladder cancer (NMIBC) is one of the most common malignant tumors in the urological system with a high risk of recurrence, and effective non-invasive biomarkers for NMIBC relapse are still needed. The human urinary proteome can reflect the status of the microenvironment of the urinary system and is an ideal source for clinical diagnosis of urinary system diseases. Our previous work used proteomics to identify 1643 high-confidence urinary proteins in the urine from a healthy population. Here, we used bioinformatics to construct a cancer-associated protein-protein interaction (PPI) network comprising 16 high-abundance urinary proteins based on the urinary proteome database. As a result, platelet-derived growth factor receptor beta (PDGFRB) was selected for further validation as a candidate biomarker for NMIBC diagnosis and prognosis. Although the levels of urinary PDGFRB showed no significant difference between patients pre- and post-surgery (n = 185, P>0.05), over 3 years of follow-up, urinary PDGFRB was shown to be significantly higher in relapsed patients (n = 68) than in relapse-free patients (n = 117, P<0.001). The levels of urinary PDGFRB were significantly correlated with the risk of 3-year recurrence of NMIBC, and these levels improved the accuracy of a NMIBC recurrence risk prediction model that included age, tumor size, and tumor number (area under the curve, 0.862; 95% CI, 0.809 to 0.914) compared to PDGFR alone. Therefore, we surmise that urinary PDGFRB could serve as a non-invasive biomarker for predicting NMIBC recurrence.

Anti-herpesvirus activity profile of 4'-thioarabinofuranosyl purine and uracil nucleosides and activity of 1-beta-D-2'-fluoro-4'-thioarabinofuranosyl guanine and 2,6-diaminopurine against clinical isolates of human cytomegalovirus.

PubMed

Machida, H; Ashida, N; Miura, S; Endo, M; Yamada, K; Kitano, K; Yoshimura, Y; Sakata, S; Ijichi, O; Eizuru, Y

1998-08-01

Newly synthesized 4'-thio- and 2'-fluoro-4'-thioarabinofuranosyl purine and pyrimidine nucleosides were compared with the corresponding 4'-oxo type arabinosyl nucleosides for anti-herpesvirus and anti-cell proliferative potencies. 4'-Thioarabinosyl- and 2'-fluoro-4'-thioarabinofuranosyl 5-substituted uracils had selective antiviral activities, but were not superior to 4'-oxo nucleosides, except for the activity of 5-ethyl-uracil 4'-thio nucleosides against herpes simplex virus. Furthermore, 4'-thio substituted derivatives of sorivudine (BV-araU) and related compounds, and 2'-fluoro-5-methyl-arabinosyluracil exhibited reduced activity against varicella-zoster virus compared with the parent compounds. The 4'-thioarabinosyluracils, except for 5-methyluracil derivatives, were inactive against human cytomegalovirus (HCMV). 4'-Thioarabinofuranosyl guanine and diaminopurine had the most potent anti-HCMV and anti-proliferative activities, whereas arabinosyl guanine and diaminopurine had only marginal antiviral activity. 2'-Fluoro-4'-thioarabinofuranosyl derivatives of guanine (4'-thio-FaraG) and 2,6-diaminopurine (4'-thio-FaraDAP), however, had particularly high activity against all herpesviruses tested with anti-proliferative activity equipotent to that of arabinosyl guanine and diaminopurine. 4'-Thio- and 2'-fluoro-4'-thioarabinofuranosyladenines exhibited biological activities similar to that of arabinosyladenine. Both 4'-thio-FaraG and 4'-thio-FaraDAP had a 6-fold lower ED50 than ganciclovir against clinical isolates of HCMV. A ganciclovir-resistant isolate, obtained from a patient who had received long-term ganciclovir-treatment, was susceptible to 4'-thio-FaraG and 4'-thio-FaraDAP.

Inhibition of herpes simplex virus DNA polymerase by purine ribonucleoside monophosphates.

PubMed

Frank, K B; Cheng, Y C

1986-02-05

Purine ribonucleoside monophosphates were found to inhibit chain elongation catalyzed by herpes simplex virus (HSV) DNA polymerase when DNA template-primer concentrations were rate-limiting. Inhibition was fully competitive with DNA template-primer during chain elongation; however, DNA polymerase-associated exonuclease activity was inhibited noncompetitively with respect to DNA. Combinations of 5'-GMP and phosphonoformate were kinetically mutually exclusive in dual inhibitor studies. Pyrimidine nucleoside monophosphates and deoxynucleoside monophosphates were less inhibitory than purine riboside monophosphates. The monophosphates of 9-beta-D-arabinofuranosyladenine, Virazole (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide), 9-(2-hydroxyethoxymethyl)guanine, and 9-(1,3-dihydroxy-2-propoxymethyl)guanine exerted little or no inhibition. In contrast to HSV DNA polymerase, human DNA polymerase alpha was not inhibited by purine ribonucleoside monophosphates. These studies suggest the possibility of a physiological role of purine ribonucleoside monophosphates as regulators of herpesvirus DNA synthesis and a new approach to developing selective anti-herpesvirus compounds.

The electrochemical properties of the purine bases : at the interface between biological conjugates to inorganic surfaces

NASA Technical Reports Server (NTRS)

Hays, Charles C.

2003-01-01

The study of the charge transfer and interfacial reactions of the purine bases in physiological solutions provides valuable knowledge, as these processes are relevant to the origins of life. It has been proposed that the adsorption of the adsorption of the purine bases on an inorganic surface could serve as a template for specifying the arrangement of amino acids in peptides.

Isolation of Purines and Pyrimidines from the Murchison Meteorite

NASA Technical Reports Server (NTRS)

Glavin, D. P.; Bada, J. K.

2003-01-01

The origin of life on Earth, and possibly on other planets such as Mars, would have required the presence of liquid water and a continuous supply of prebiotic organic compounds. The delivery of organic matter by asteroids, comets, and carbonaceous meteorites could have contributed to the early Earth's prebiotic inventory by seeding the planet with biologically important organic compounds. A wide variety of prebiotic organic compounds have previously been detected in the Murchison CM type carbonaceous chondrite including amino acids, purines and pyrimidines'. These compounds play a major role in terrestrial biochemistry and are integral components of proteins, DNA and RNA. In this study we developed a new extraction technique using sublimation in order to isolate purines and pyrimidines from Murchison2, which is cleaner and more time efficient that traditional methods3. Several purines including adenine, guanine, hypoxanthine and xanthine were positively identified by high performance liquid chromatography and ultraviolet absorption detection in our Murchison extracts. The purines detected in Murchison do not correlate with the distribution of nucleobases found in geological environments on Earth4. Moreover, the abundance of extraterrestrial amino acids and the low level of terrestrial amino acid contaminants found in Murchison', support the idea that the purines in t h s meteorite are extraterrestrial in origin.

Transcriptomic analysis of genes in the nitrogen recycling pathway of meat-type chickens divergently selected for feed efficiency.

PubMed

Aggrey, S E; Lee, J; Karnuah, A B; Rekaya, R

2014-04-01

The understanding of the dynamics of ammonia detoxification and excretion in uricotelic species is lagging behind ureotelic species. The relative expression of genes involved in nitrogen recycling and feed efficiency in chickens is unknown. The objective of this study was to investigate the transcriptomics differences in key genes in the nitrogen (N) metabolism and purine biosynthesis pathway in a chicken population divergently selected for low (LRFI) or high (HRFI) residual feed intake at days 35 and 42 using duodenum, liver, pectoralis major (P. major) and kidney. There was a significant positive correlation between RFI and fecal N. The purine salvage pathway was activated in the LRFI compared with HRFI at days 42. The birds in the LRFI population attained greater feed efficiency by having lower FI, increasing their protein retention and producing adequate glutamine to maintain growth compared with the HRFI line. To maintain growth, excess N is deaminated mostly to generate purine nucleotides. Generating purine nucleotides primarily from the purine biosynthesis pathway is energetically costly, and to preserve energy, they preferentially generate nucleotides from the purine salvage pathway. The LRFI birds need to generate sufficient nucleotides to maintain growth despite reduced FI that then results in reduced fecal N. © 2013 Stichting International Foundation for Animal Genetics.

Reducing Electroosmotic Flow Enables DNA Separations in Ultrathin Channels.

DTIC Science & Technology

1998-08-01

Chemical structure of DNA bases 2 Figure 1-2: Schematic diagram of DNA base pairing 5 Figure 1-3: Schematic diagram of the capillary and the...hydrogen atoms near one of the Figure 1-1: A. Chemical structure of the DNA backbone. B. Chemical structure of DNA bases . The DNA backbone consists...of pentose sugar (deoxyribose) held together by phosphodiester bonds. The DNA bases that are derivatives of purine are adenine (A) and guanine (G

Iron Sequestration in Microbiota Biofilms As A Novel Strategy for Treating Inflammatory Bowel Disease.

PubMed

Motta, Jean-Paul; Allain, Thibault; Green-Harrison, Luke E; Groves, Ryan A; Feener, Troy; Ramay, Hena; Beck, Paul L; Lewis, Ian A; Wallace, John L; Buret, Andre G

2018-06-08

Significant alterations of intestinal microbiota and anemia are hallmarks of inflammatory bowel disease (IBD). It is widely accepted that iron is a key nutrient for pathogenic bacteria, but little is known about its impact on microbiota associated with IBD. We used a model device to grow human mucosa-associated microbiota in its physiological anaerobic biofilm phenotype. Compared to microbiota from healthy donors, microbiota from IBD patients generate biofilms ex vivo that were larger in size and cell numbers, contained higher intracellular iron concentrations, and exhibited heightened virulence in a model of human intestinal epithelia in vitro and in the nematode Caenorhabditis elegans. We also describe an unexpected iron-scavenging property for an experimental hydrogen sulfide-releasing derivative of mesalamine. The findings demonstrate that this new drug reduces the virulence of IBD microbiota biofilms through a direct reduction of microbial iron intake and without affecting bacteria survival or species composition within the microbiota. Metabolomic analyses indicate that this drug reduces the intake of purine nucleosides (guanosine), increases the secretion of metabolite markers of purine catabolism (urate and hypoxanthine), and reduces the secretion of uracil (a pyrimidine nucleobase) in complex multispecies human biofilms. These findings demonstrate a new pathogenic mechanism for dysbiotic microbiota in IBD and characterize a novel mode of action for a class of mesalamine derivatives. Together, these observations pave the way towards a new therapeutic strategy for treatment of patients with IBD.

Risks of repeated visits for uninvestigated dyspepsia in three community hospitals of Khon Kaen, Thailand.

PubMed

Premgamone, Amorn; Maskasem, Srinoi; Thamrongwarangoon, Apisit; Ussavaphark, Wichai

2010-03-01

Uninvestigated dyspepsia (UD) is common and only 26.4% of these are peptic ulcer disease, while 50% are non-ulcer dyspepsia. A recent study found that nephrolithiasis with urinary tract infection may have the dyspeptic symptoms. The authors searched for any associations between repeated UD and pyuria, hematuria and other factors. A case-control study was performed. It consisted of 489 patients with repeated UD who had visited community hospitals for at least two times per year and 489 controls sampled from the data of the subjects, free of dyspeptic symptoms, from the multi-stage random survey for subjective health complaints in the same province. Multivariate logistic regression models were used for case-control comparisons. By logistic regression analysis, UD was significantly associated with problems caused by purine-rich foods (PRFs), chronic fatigue, flank paresthesia, hematuria, myofascial pain, and pyuria. The respective adjusted odds ratios and 95% confidence interval (CI) were: 6.67 (4.58, 9.68), 5.06 (3.46, 7.40), 3.98 (2.41, 6.60), 2.97 (2.01, 4.38), 1.91 (1.32, 2.76) and 1.58 (1.01, 2.45). The variables of age (> 48), sex, dysuria, poly-arthralgia, headache and back pain were not significantly associated with UD. The foods that aggravated UD were bamboo shoots, fermented rice noodles, beef alcohol and insects. The rate of pyuria and hematuria was significantly increased with the number of visits within a year [p-value (Chi-square for trend), 0.015 and 0.032]. These findings indicate that pyuria, hematuria, and purine-rich foods were associated with repeated hospital visits for dyspepsia.

Measurement of urinary metanephrines to screen for pheochromocytoma in an unselected hospital referral population

PubMed Central

Brain, Keith L.; Kay, Jonathan; Shine, Brian

2009-01-01

Background Despite the rarity of pheochromocytoma, the dangers of uncontrolled severe hypertension and the very effective surgical treatment of this condition mean that diagnosis is important. Urinary or plasma catecholamines or catecholamine-derivatives are commonly used to screen for pheochromocytomas prior to imaging. This study investigates whether derived measures obtained from 24-hour urinary metanephrine results, patient age and sex can better predict tumors in populations with a low pre-test probability. Methods This study takes a pragmatic approach by retrospectively studying the outcomes of an unselected population referred for urinary metanephrine testing (1819 patients) to a tertiary hospital laboratory, and investigates the usefulness of some simple derivative measures for detecting pheochromocytoma. Urinary 24-hour excretion of metanephrine, normetanephrine and 3-methoxytyramine were normalized by dividing by an age- and sex- specific reference range. The ability of products of these normalized measures to predict pheochromocytomas was assessed, compared to a gold standard of biopsy-confirmed tumor. Results The normalized product of urinary metanephrine and normetanephrine excretion (nMAD.nNMT) proved to be a highly sensitive (100%) and specific (99.1%) measure yielding a positive predictive value 82%. Receiver-operator characteristic curves were not improved by including the normalized 3-methoxytyramine concentrations in the product. nMAD.nNMT gave higher sensitivity and specificity than either test alone. Conclusion We suggest that nMAD.nNMT is a useful measure for identifying pheochromocytoma in a population with a low pre-test probability. PMID:16990424

Radical-induced purine lesion formation is dependent on DNA helical topology.

PubMed

Terzidis, Michael A; Prisecaru, Andreea; Molphy, Zara; Barron, Niall; Randazzo, Antonio; Dumont, Elise; Krokidis, Marios G; Kellett, Andrew; Chatgilialoglu, Chryssostomos

2016-11-01

Herein we report the quantification of purine lesions arising from gamma-radiation sourced hydroxyl radicals (HO • ) on tertiary dsDNA helical forms of supercoiled (SC), open circular (OC), and linear (L) conformation, along with single-stranded folded and non-folded sequences of guanine-rich DNA in selected G-quadruplex structures. We identify that DNA helical topology and folding plays major, and unexpected, roles in the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) and 8-oxo-7,8-dihydro-2'-deoxyadenosine (8-oxo-dA), along with tandem-type purine lesions 5',8-cyclo-2'-deoxyguanosine (5',8-cdG) and 5',8-cyclo-2'-deoxyadenosine (5',8-cdA). SC, OC, and L dsDNA conformers together with folded and non-folded G-quadruplexes d[TGGGGT] 4 (TG4T), d[AGGG(TTAGGG) 3 ] (Tel22), and the mutated tel24 d[TTGGG(TTAGGG) 3 A] (mutTel24) were exposed to HO • radicals and purine lesions were then quantified via stable isotope dilution LC-MS/MS analysis. Purine oxidation in dsDNA follows L > OC ≫ SC indicating greater damage towards the extended B-DNA topology. Conversely, G-quadruplex sequences were significantly more resistant toward purine oxidation in their unfolded states as compared with G-tetrad folded topologies; this effect is confirmed upon comparative analysis of Tel22 (∼50% solution folded) and mutTel24 (∼90% solution folded). In an effort to identify the accessibly of hydroxyl radicals to quadruplex purine nucleobases, G-quadruplex solvent cavities were then modeled at 1.33 Å with evidence suggesting that folded G-tetrads may act as potential oxidant traps to protect against chromosomal DNA damage.

Adenylosuccinate Is an Insulin Secretagogue Derived from Glucose-Induced Purine Metabolism.

PubMed

Gooding, Jessica R; Jensen, Mette V; Dai, Xiaoqing; Wenner, Brett R; Lu, Danhong; Arumugam, Ramamani; Ferdaoussi, Mourad; MacDonald, Patrick E; Newgard, Christopher B

2015-10-06

Pancreatic islet failure, involving loss of glucose-stimulated insulin secretion (GSIS) from islet β cells, heralds the onset of type 2 diabetes (T2D). To search for mediators of GSIS, we performed metabolomics profiling of the insulinoma cell line 832/13 and uncovered significant glucose-induced changes in purine pathway intermediates, including a decrease in inosine monophosphate (IMP) and an increase in adenylosuccinate (S-AMP), suggesting a regulatory role for the enzyme that links the two metabolites, adenylosuccinate synthase (ADSS). Inhibition of ADSS or a more proximal enzyme in the S-AMP biosynthesis pathway, adenylosuccinate lyase, lowers S-AMP levels and impairs GSIS. Addition of S-AMP to the interior of patch-clamped human β cells amplifies exocytosis, an effect dependent upon expression of sentrin/SUMO-specific protease 1 (SENP1). S-AMP also overcomes the defect in glucose-induced exocytosis in β cells from a human donor with T2D. S-AMP is, thus, an insulin secretagogue capable of reversing β cell dysfunction in T2D. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Structure and Electronic Spectra of Purine-Methyl Viologen Charge Transfer Complexes

PubMed Central

Jalilov, Almaz S.; Patwardhan, Sameer; Singh, Arunoday; Simeon, Tomekia; Sarjeant, Amy A.; Schatz, George C.; Lewis, Frederick D.

2014-01-01

The structure and properties of the electron donor-acceptor complexes formed between methyl viologen (MV) and purine nucleosides and nucleotides in water and the solid state have been investigated using a combination of experimental and theoretical methods. Solution studies were performed using UV-vis and 1H NMR spectroscopy. Theoretical calculations were performed within the framework of density functional theory (DFT). Energy decomposition analysis indicates that dispersion and induction (charge-transfer) interactions dominate the total binding energy, whereas electrostatic interactions are largely repulsive. The appearance of charge transfer bands in the absorption spectra of the complexes are well described by time-dependent (TD) DFT and are further explained in terms of the redox properties of purine monomers and solvation effects. Crystal structures are reported for complexes of methyl viologen with the purines 2′-deoxyguanosine 3′-monophosphate GMP (DAD′DAD′ type) and 7-deazaguanosine zG (DAD′ADAD′ type). Comparison of the structures determined in the solid state and by theoretical methods in solution provides valuable insights into the nature of charge-transfer interactions involving purine bases as electron donors. PMID:24294996

Purine metabolism in Toxoplasma gondii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krug, E.C.; Marr, J.J.; Berens, R.L.

1989-06-25

We have studied the incorporation and interconversion of purines into nucleotides by freshly isolated Toxoplasma gondii. They did not synthesize nucleotides from formate, glycine, or serine. The purine bases hypoxanthine, xanthine, guanine, and adenine were incorporated at 9.2, 6.2, 5.1, and 4.3 pmol/10(7) cells/h, respectively. The purine nucleosides adenosine, inosine, guanosine, and xanthosine were incorporated at 110, 9.0, 2.7, and 0.3 pmol/10(7) cells/h, respectively. Guanine, xanthine, and their respective nucleosides labeled only guanine nucleotides. Inosine, hypoxanthine, and adenine labeled both adenine and guanine nucleotide pools at nearly equal ratios. Adenosine kinase was greater than 10-fold more active than the nextmore » most active enzyme in vitro. This is consistent with the metabolic data in vivo. No other nucleoside kinase or phosphotransferase activities were found. Phosphorylase activities were detected for guanosine and inosine; no other cleavage activities were detected. Deaminases were found for adenine and guanine. Phosphoribosyltransferase activities were detected for all four purine nucleobases. Interconversion occurs only in the direction of adenine to guanine nucleotides.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meadows, J.R.

The ozone-induced degradation rates of various purine bases, hydroxylated purine compounds, pyrimidine bases, and uric acid were compared. Of the compounds examined, uric acid was the one most readily degraded while the parent compounds, purine and pyrimidine, were the ones most resistant to ozonation. When the breakdown of hydroxylated purines was studied, it was determined that the more OH substituents on the purine, the more readily it was degraded. Because of the preferential attack by ozone on uric acid in solutions containing a nucleic acid base plus uric acid, the presence of the uric acid had a sparing effect onmore » the base. This effect was readily apparent for guanine, thymine, and uracil which were the bases more labile to ozone. Two of the ozonation products of uric acid were identified as allantoin and urea. Ozonation of bovine and swine erythrocyte suspensions resulted in oxidation of oxyhemoglobin to methemoglobin, formation of thiobarbituric acid-reactive materials-a measure of lipid oxidation- and lysis of the red cells. Each of these changes was inhibited by the presence of uric acid in the solution during ozonation.« less

77 FR 11133 - Draft Guidance for Industry on Complicated Urinary Tract Infections: Developing Drugs for...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-24

... abnormalities of the urinary tract, but are also considered to be a subset of cUTI. Different types of bacteria can cause cUTI, but Gram-negative bacteria are most often associated with cUTI. This draft guidance..., based on resolution of clinical symptoms and eradication of bacteria from the urinary tract, was derived...

Influence of different levels of concentrate and ruminally undegraded protein on digestive variables in beef heifers.

PubMed

Pina, D S; Valadares Filho, S C; Tedeschi, L O; Barbosa, A M; Valadares, R F D

2009-03-01

This experiment evaluated the effect of 2 levels of diet concentrate (20 and 40% of DM) and 2 levels of ruminally undegraded protein (RUP: 25 and 40% of CP) on nutrient intake, total and partial apparent nutrient digestibility, microbial protein synthesis, and ruminal and physiological variables. Eight Nellore heifers (233 +/- 14 kg of BW) fitted with ruminal, abomasal, and ileal cannulas were used. The animals were held in individual sheltered pens of approximately 15 m(2) and fed twice daily at 0800 and 1600 h for ad libitum intake. Heifers were allocated in two 4 x 4 Latin square designs, containing 8 heifers, 4 experimental periods, and 4 treatments in a 2 x 2 factorial arrangement. All statistical analyses were performed using PROC MIXED of SAS. Titanium dioxide (TiO(2)) and chromic oxide (Cr(2)O(3)) were used to estimate digesta fluxes and fecal excretion. Purine derivative (PD) excretion and abomasal purine bases were used to estimate the microbial N (MN) synthesis. No significant interaction (P > 0.10) between dietary levels of RUP and concentrate was observed. There was no effect of treatment (P = 0.24) on DMI. Both markers led to the same estimates of fecal, abomasal, and ileal DM fluxes, and digestibilities of DM and individual nutrients. Ruminal pH was affected by sampling time (P < 0.001), but no interaction between treatment and sampling time was observed (P = 0.71). There was an interaction between treatment and sampling time (P < 0.001) for ruminal NH(3)-N concentration. A linear decrease (P = 0.04) over sampling time was observed for the higher level of RUP, whereas a quadratic effect (P < 0.001) of sampling time was observed for the lower level of RUP. The higher level of dietary concentrate led to greater MN yield regardless of the level of RUP. The MN yield and the efficiency of microbial yield estimated from urinary PD excretion produced greater (P < 0.01) values than those estimated by either TiO(2) or Cr(2)O(3), which did not differ (P = 0.63) from each other. However, all methods yielded values that were within the range reported in the literature. In conclusion, no interactions between dietary levels of RUP and concentrate were observed for ruminal and digestive parameters. Neither RUP nor concentrate level affected DMI. Titanium dioxide showed to be similar to Cr(2)O(3) as an external marker to measure digestibility and nutrient fluxes in cattle.

Activated platelet-derived growth factor β receptor and Ras-mitogen-activated protein kinase pathway in natural bovine urinary bladder carcinomas.

PubMed

Corteggio, Annunziata; Di Geronimo, Ornella; Roperto, Sante; Roperto, Franco; Borzacchiello, Giuseppe

2012-03-01

Bovine papillomavirus types 1 or 2 (BPV-1/2) are involved in the aetiopathogenesis of bovine urinary bladder cancer. BPV-1/2 E5 activates the platelet-derived growth factor β receptor (PDGFβR). The aim of this study was to analyse the Ras/mitogen-activated protein kinase (MAPK) pathway in relation to activation of PDGFβR in natural bovine urinary bladder carcinomas. Co-immunoprecipitation and Western blot analysis demonstrated that recruitment of growth factor receptor bound protein 2 (GRB-2) and Sos-1 to the activated PDGFβR was increased in carcinomas compared to normal tissues. Higher grade bovine urinary bladder carcinomas were associated with activation of Ras, but not with activation of downstream mitogen-activated protein kinase/extracellular signal-regulated kinase (Mek 1/2) or extracellular signal-regulated kinase (Erk 1/2). Copyright © 2011 Elsevier Ltd. All rights reserved.

Uridine Affects Liver Protein Glycosylation, Insulin Signaling, and Heme Biosynthesis

PubMed Central

Urasaki, Yasuyo; Pizzorno, Giuseppe; Le, Thuc T.

2014-01-01

Purines and pyrimidines are complementary bases of the genetic code. The roles of purines and their derivatives in cellular signal transduction and energy metabolism are well-known. In contrast, the roles of pyrimidines and their derivatives in cellular function remain poorly understood. In this study, the roles of uridine, a pyrimidine nucleoside, in liver metabolism are examined in mice. We report that short-term uridine administration in C57BL/6J mice increases liver protein glycosylation profiles, reduces phosphorylation level of insulin signaling proteins, and activates the HRI-eIF-2α-ATF4 heme-deficiency stress response pathway. Short-term uridine administration is also associated with reduced liver hemin level and reduced ability for insulin-stimulated blood glucose removal during an insulin tolerance test. Some of the short-term effects of exogenous uridine in C57BL/6J mice are conserved in transgenic UPase1 −/− mice with long-term elevation of endogenous uridine level. UPase1 −/− mice exhibit activation of the liver HRI-eIF-2α-ATF4 heme-deficiency stress response pathway. UPase1 −/− mice also exhibit impaired ability for insulin-stimulated blood glucose removal. However, other short-term effects of exogenous uridine in C57BL/6J mice are not conserved in UPase1 −/− mice. UPase1 −/− mice exhibit normal phosphorylation level of liver insulin signaling proteins and increased liver hemin concentration compared to untreated control C57BL/6J mice. Contrasting short-term and long-term consequences of uridine on liver metabolism suggest that uridine exerts transient effects and elicits adaptive responses. Taken together, our data support potential roles of pyrimidines and their derivatives in the regulation of liver metabolism. PMID:24918436

POTENTIAL TO REDUCE URINARY TRACT INFECTIONS WITH THE USE OF BLADDER SCANNERS IN MATERNITY CARE.

PubMed

Lovell, Belinda; Steen, Mary

2017-03-01

The National Medical Research Council Australia website states that 20% of hospital acquired infections are urinary tract infections (UTIs). This percentage is derived from a study involving 75,694 participants, undertaken in England, Wales, Northern Ireland and the Republic of Ireland and of the reported UTIs, 40-57% are caused by urinary catheters (Smyth et al. 2008).

Rituximab with pentostatin or cladribine: an effective combination treatment for hairy cell leukemia after disease recurrence.

PubMed

Else, Monica; Dearden, Claire E; Matutes, Estella; Forconi, Francesco; Lauria, Francesco; Ahmad, Humayun; Kelly, Susan; Liyanage, Anandika; Ratnayake, Vijitha; Shankari, Jagadeesan; Whalley, Ioana; Catovsky, Daniel

2011-06-01

The purine analogs pentostatin and cladribine are effective treatments for hairy cell leukemia (HCL). However, alternative treatments are needed for patients with recurrent disease. We reviewed retrospectively data from 18 patients who were retreated with either pentostatin (n = 12) or cladribine (n = 6) in combination with rituximab, after 1-6 (median 2) previous treatments with either purine analog as a single agent. All 18 patients responded to therapy, with a complete response (CR) rate of 89%. This compared favorably with CR rates of 68% after second-line therapy and 47% after third-line therapy in 88 patients retreated one or more times with a purine analog alone. Toxicity with the combination treatment was minimal. At a median follow-up of 36 months (range 5-83 months) all 16 complete responders remained in CR, while one partial responder developed recurrent disease at 10 months. The estimated recurrence rate at 3 years was 7%. This compares with 21% after second-line therapy and 42% after third-line therapy in the 88 patients retreated with a purine analog alone. Furthermore, it was a marked improvement on the 55% recurrence at 3 years previously seen in these same 18 patients after their own first-line treatment with single-agent pentostatin or cladribine (p = 0.006). The combination of a purine analog with rituximab was safe and effective for patients with recurrent HCL. The results suggest an added benefit compared with single-agent purine analog therapy.

[Direct determination of purine bases in tea by reversed-phase high performance liquid chromatography].

PubMed

Ding, M; Yang, H; Xiao, S; Chen, P

1999-09-01

A reversed-phase high performance liquid chromatographic(RP-HPLC) method for the direct determination of three purine bases(theobromin, theophyllin and caffeine) in tea was developed. An ODS column with Zorbax SB-C18(4.6 mm i.d. x 250 mm, 5 microns) was employed. The aqueous solution of methanol containing 0.05% of acetic acid and 0.25% of N,N-dimethylformamide(DMF) was used as eluent with a flow rate of 0.8 mL/min. In this method, the aqueous extract of tea can be injected into HPLC directly, but in current HPLC methods for purine bases the coexisted tea polyphenols must be pre-separated. The three purine bases in tea were separated without any interference from the coexisted tea polyphenols. This method is simple (without any special sample pretreatment) and sensitive with detection limits (S/N = 3) of 0.7, 0.9 and 1.8 mg/L for theobromin, theophyllin and caffeine respectively. The linear range of the calibration curve of peak area for the three purine bases were from 6 mg/L to 1,000 mg/L with a correlation coefficient (r) of 0.998-0.999.

Acyclic phosph(on)ate inhibitors of Plasmodium falciparum hypoxanthine-guanine-xanthine phosphoribosyltransferase

PubMed Central

Clinch, Keith; Crump, Douglas R.; Evans, Gary B.; Hazleton, Keith Z.; Mason, Jennifer M.; Schramm, Vern L.

2013-01-01

The pathogenic protozoa responsible for malaria lack enzymes for the de novo synthesis of purines and rely on purine salvage from the host. In Plasmodium falciparum (Pf), hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGXPRT) converts hypoxanthine to inosine monophosphate and is essential for purine salvage making the enzyme an anti-malarial drug target. We have synthesized a number of simple acyclic aza-C- nucleosides and shown that some are potent inhibitors of Pf HGXPRT while showing excellent selectivity for the Pf versus the human enzyme. PMID:23810424

Association of increased urine brain derived neurotrophic factor with lower urinary tract symptoms in men with benign prostatic hyperplasia.

PubMed

Wang, Long-Wang; Li, Jian-Long; Yu, Yi; Xiao, Rui-Hai; Huang, Hong-Wei; Kuang, Ren-Rui; Hai, Bo

2017-08-01

Urinary brain-derived neurotrophic factor (BDNF), an ubiquitous neurotrophin, was found to rise in patients with benign prostatic hyperplasia (BPH). We hypothesized that the urinary level of BDNF could be a potential biomarker for lower urinary tract symptoms (LUTS) in patients with BPH. Totally, 76 patients with BPH-caused LUTS and 32 male control subjects without BPH were enrolled. International Prostate Symptom Score (IPSS) was applied to assess the symptom severity of LUTS. Urodynamic tests were performed for the diagnosis of underlying detrusor overactivity (DO) in the patients with BPH. Urine samples were collected from all subjects. Urinary BDNF levels were measured using enzyme-linked immunosorbent assays and normalized by urinary creatinine (Cr) levels. Seventy-six BPH patients were divided into moderate LUTS group (n=51, 720) according to the IPSS. Of the 76 BPH patients, DO was present in 34 (44.7%) according to the urodynamic test. The urinary BDNF/Cr levels were significantly higher in BPH patients with moderate LUTS (8.29±3.635, P<0.0001) and severe LUTS (11.8±6.44, P<0.0001) than normal controls (1.71±0.555). Patients with severe LUTS tended to have higher urinary BDNF/Cr levels than patients with moderate LUTS (11.8±6.44 vs. 8.29±3.635, P=0.000). The conditions of BPH with LUTS correlated with elevated urinary BDNF levels, and urinary BDNF levels were even higher in BPH-DO patients. The results of this study have provided evidence to suggest that urinary BDNF level test could evaluate the severity of LUTS in BPH patients, and BDNF level can be used as a biomarker for the diagnosis of DO in BPH patients.

Aminoimidazole Carboxamide Ribotide Exerts Opposing Effects on Thiamine Synthesis in Salmonella enterica

PubMed Central

Bazurto, Jannell V.; Heitman, Nicholas J.

2015-01-01

ABSTRACT In Salmonella enterica, the thiamine biosynthetic intermediate 5-aminoimidazole ribotide (AIR) can be synthesized de novo independently of the early purine biosynthetic reactions. This secondary route to AIR synthesis is dependent on (i) 5-amino-4-imidazolecarboxamide ribotide (AICAR) accumulation, (ii) a functional phosphoribosylaminoimidazole-succinocarboxamide (SAICAR) synthetase (PurC; EC 6.3.2.6), and (iii) methionine and lysine in the growth medium. Studies presented here show that AICAR is a direct precursor to AIR in vivo. PurC-dependent conversion of AICAR to AIR was recreated in vitro. Physiological studies showed that exogenous nutrients (e.g., methionine and lysine) antagonize the inhibitory effects of AICAR on the ThiC reaction and decreased the cellular thiamine requirement. Finally, genetic results identified multiple loci that impacted the effect of AICAR on thiamine synthesis and implicated cellular aspartate levels in AICAR-dependent AIR synthesis. Together, the data here clarify the mechanism that allows conditional growth of a strain lacking the first five biosynthetic enzymes, and they provide additional insights into the complexity of the metabolic network and its plasticity. IMPORTANCE In bacteria, the pyrimidine moiety of thiamine is derived from aminoimidazole ribotide (AIR), an intermediate in purine biosynthesis. A previous study described conditions under which AIR synthesis is independent of purine biosynthesis. This work is an extension of that previous study and describes a new synthetic pathway to thiamine that depends on a novel thiamine precursor and a secondary activity of the biosynthetic enzyme PurC. These findings provide mechanistic details of redundancy in the synthesis of a metabolite that is essential for nucleotide and coenzyme biosynthesis. Metabolic modifications that allow the new pathway to function or enhance it are also described. PMID:26100042

Inhibitory effect of extracellular purine nucleotide and nucleoside concentrations on T cell proliferation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiler, Monica; Schmetzer, Helga; German Research Center for Environmental Health, Munich

The release of nucleic acids and derivatives after tissue-injury may affect cellular immune-response. We studied the impact of extracellular ribo-, desoxyribonucleotides and nucleosides on T-cell immunity. Peripheral-blood-mononuclear-cells (PBMCs) or isolated CD3{sup +}T-cells obtained from 6 healthy donors were stimulated via CD3/CD28 Dynabeads or dendritic cells (DCs) in the presence or absence of pyrimidine-, purine-nucleotides and -nucleosides (range 2–200 µM). Addition of deoxy-, guanosine-triphosphate (dGTP, GTP) and guanosine resulted concentration dependent in a complete, adenosine-triphosphate (ATP) in a partial inhibition of the induced T-cell-proliferation. Deoxyadenosine-triphosphate (dATP), adenosine and the pyrimidine-ribo- and -deoxyribonucleotides displayed no inhibitory capacity. Inhibitory effects of dGTP andmore » GTP, but not of guanosine and ATP were culture-media-dependent and could be almost abrogated by use of the serum-free lymphocyte-culture-media X-Vivo15 instead of RPMI1640 with standard-supplementation. In contrast to RPMI1640, X-Vivo15 resulted in a significant down-regulation of the cell-surface-located ectonucleotidases CD39 (Ecto-Apyrase) and CD73 (Ecto-5′-Nucleotidase), critical for the extracellular nucleotides-hydrolysis to nucleosides, explaining the loss of inhibition mediated by dGTP and GTP, but not Guanosine. In line with previous findings ATP was found to exert immunosuppressive effects on T-cell-proliferation. Purine-nucleotides, dGTP and GTP displayed a higher inhibitory capacity, but seem to be strictly dependent on the microenvironmental conditions modulating the responsiveness of the respective T-lymphocytes. Further evaluation of experimental and respective clinical settings should anticipate these findings.« less

Effects of pH, temperature, and chemical structure on the stability of S-(purin-6-yl)-L-cysteine: evidence for a novel molecular rearrangement mechanism to yield N-(purin-6-yl)-L-cysteine.

PubMed

Elfarra, A A; Hwang, I Y

1996-01-01

The stability of S-(purin-6-yl)-L-cysteine (SPC), a kidney-selective prodrug of 6-mercaptopurine and a putative metabolite of 6-chloropurine, was investigated under various pH and temperature conditions. At room temperature, the half-life (t 1/2) of SPC at either highly acidic (pH 3.6) or basic conditions (pH 9.6) was longer than at neutral or slightly acidic or basic conditions (pH 5.7-8.75). The primary degradation product, N-(purin-6-yl)-L-cysteine (NPC), was isolated using Sephadex LH-20 chromatography and characterized by 1H NMR and FAB/MS after derivatization with 2-iodoacetic acid. These results reveal novel stability requirements and implicate the cysteinyl amino group and the purinyl N-1 nitrogen in the mechanism of SPC rearrangement to NPC. Further evidence for this hypothesis was provided by the findings that the stability of SPC in phosphate buffer (pH 7.4) at 37 degrees C was similar to that of S-(guanin-6-yl)-L-cysteine, whereas S-(purin-6-yl)-N-acetyl-L-cysteine and S-(purin-6-yl)glutathione which have their cysteine amino groups blocked were much more stable than SPC. S-(Purin-6-yl)-L-homocysteine (SPHC) was also more stable than SPC, possibly because the formation of a 6-membered ring transition state as would be expected with SPHC is kinetically less favored than the formation of a 5-membered ring transition state as would be expected with SPC. These results may explain previous in vivo metabolism results of SPC and its analogs and may contribute to a better understanding of stability of structurally related cysteine S-conjugates.

Urinary angiotensinogen as a potential biomarker of intrarenal renin-angiotensin system activity in Chinese chronic kidney disease patients.

PubMed

Xu, Z; Xu, B; Xu, C

2015-06-01

Urinary angiotensinogen (AGT) mainly derives from the AGT produced in proximal tubular cells. Evidence exists that supports the correlation between urinary AGT and circulating AGT. To investigate the role of urinary AGT as a potential biomarker of intrarenal renin-angiotensin system activity in Chinese chronic kidney disease (CKD) patients. ELISA-based method used to quantify urinary AGT. Analyzed the relationship between urinary AGT and intrarenal angiotensin II (Ang II) activity in 128 CKD patients. ELISA was applied to measure the urinary and plasma renin activity, AGT, Ang II and aldosterone. Furthermore expression levels of intrarenal renin, AGT, Ang II and Ang II receptor were examined by immunohistochemistry staining (IHCS) in 72 CKD patients undergoing renal biopsy. The logarithmic transformation Log(urinary AGT/UCre) levels showed a normal distribution. Therefore, Log(urinary AGT/UCre) levels were used for the analyses. Average urinary AGT was 2.02 ± 0.55 ng/(mg Cr). Hypertension, urinary protein, urinary Ang II and urinary type IV collagen (Col IV) positively correlated with urinary AGT. Estimated glomerular filtration rate (eGFR), urinary sodium and serum AGT negatively correlated with urinary AGT. Multiple regression analysis indicated that low serum AGT, high urinary protein, urinary Ang II and urinary Col IV correlated significantly with high urinary AGT. We observed positive correlation between urinary AGT and positive IHCS area of AGT, Ang II and Ang II type 1 receptor in renal tissue. These data suggest that urinary AGT might be a potential biomarker of intrarenal Ang II activity in CKD patients.

Mechanisms of the Formation of Adenine, Guanine, and Their Analogues in UV-Irradiated Mixed NH3:H2O Molecular Ices Containing Purine

NASA Astrophysics Data System (ADS)

Bera, Partha P.; Stein, Tamar; Head-Gordon, Martin; Lee, Timothy J.

2017-08-01

We investigated the formation mechanisms of the nucleobases adenine and guanine and the nucleobase analogues hypoxanthine, xanthine, isoguanine, and 2,6-diaminopurine in a UV-irradiated mixed 10:1 H2O:NH3 ice seeded with precursor purine by using ab initio and density functional theory computations. Our quantum chemical investigations suggest that a multistep reaction mechanism involving purine cation, hydroxyl and amino radicals, together with water and ammonia, explains the experimentally obtained products in an independent study. The relative abundances of these products appear to largely follow from relative thermodynamic stabilities. The key role of the purine cation is likely to be the reason why purine is not functionalized in pure ammonia ice, where cations are promptly neutralized by free electrons from NH3 ionization. Amine group addition to purine is slightly favored over hydroxyl group attachment based on energetics, but hydroxyl is much more abundant due to higher abundance of H2O. The amino group is preferentially attached to the 6 position, giving 6-aminopurine, that is, adenine, while the hydroxyl group is preferentially attached to the 2 position, leading to 2-hydroxypurine. A second substitution by hydroxyl or amino group occurs at either the 6 or the 2 position depending on the first substitution. Given that H2O is far more abundant than NH3 in the experimentally studied ices (as well as based on interstellar abundances), xanthine and isoguanine are expected to be the most abundant bi-substituted photoproducts.

Incorporation of Exogenous Purines and Pyrimidines by Methanococcus voltae and Isolation of Analog-Resistant Mutants

PubMed Central

Bowen, Timothy L.; Whitman, William B.

1987-01-01

Methanococcus voltae incorporated exogenous adenine, guanine, hypoxanthine, and uracil, but not thymine. Growth of M. voltae was also sensitive to purine and pyrimidine analogs. Of the 20 analogs tested, 12 were inhibitory at 1 mg/ml. The most effective inhibitors were purine analogs with endocyclic substitutions. Nucleoside analogs and analogs with exocyclic substitutions or additions were less effective. Four purine analogs, 8-aza-2,6-diaminopurine, 8-azaguanine, 8-azahypoxanthine, and 6-mercaptopurine and one pyrimidine analog, 6-azauracil, were especially toxic. The MICs were 20, 0.5, 2.0, 80, and 10 μg/ml, respectively. Spontaneous resistance mutants were isolated for these five analogs. The MICs for these mutants were 20.5, 8.2, >65, >41, and 20.5 mg/ml, respectively. These concentrations far exceeded the solubilities of the analogs and represented an increase in resistance of at least three orders of magnitude. In addition to demonstrating cross resistance to several of the analogs, four of these mutants lost the ability to incorporate exogenous bases. These appeared to be mutations in the salvage pathways for purines and pyrimidines. In contrast, the mutant resistant to 6-mercaptopurine was not defective in purine uptake. Instead, it degraded 6-mercaptopurine. In the presence or absence of high concentrations of the analogs, the growth rates of the resistant mutants were no less than one-half of the growth rate of the wild type in the absence of the analog. The high level of resistance and rapid growth are very desirable properties for the application of the mutants in genetic experiments. PMID:16347408

Development of a bacterial screen for novel hypoxanthine-guanine phosphoribosyltransferase substrates.

PubMed

Shivashankar, K; Subbayya, I N; Balaram, H

2001-10-01

The lack of de novo purine biosynthesis in many parasitic protozoans makes the enzymes in the salvage of purines attractive chemotherapeutic targets. Hypoxanthine-guanine phosphoribosyltransferase (HGPRT) is a key enzyme for purine salvage and bacterial complementation screens for HGPRT inhibitors are known. The low KMS for purine bases makes purine analogs unattractive as competitive inhibitors for this enzyme. Despite the availability of many crystal structures of HGPRTs, it is only recently that selective inhibitors of the enzyme have been developed. Therefore, novel purine analogs which act as substrates for the HGPRT reaction and thereby inhibit downstream enzymes or get incorporated into the nucleotide pool are an attractive altenative for drug design. We have used a combination of two E. coli strains Sphi606 (ara, deltapro-gpt-lac, thi, hpt) and Sphi609 (ara, deltapro-gpt-lac, thi, hpt, pup, purH,J, strA) to identify inhibitors and substrates of HGPRT. E. coli Sphi609 is deficient in both de novo synthesis as well as salvage enzymes of purine nucleotide synthesis, while E. coli Sphi606 is deficient in salvage enzymes only. Hence, expression of functional HGPRTs in E. coli Sphi606 grown in minimal medium makes it susceptible to HGPRT substrates, which inhibit downstream processes. Growth of E. coli Sphi609 in minimal medium can be made conditional for the expression of a functional HGPRT and this growth would be susceptible to both HGPRT substrate analogs and inhibitors. A substance that strictly acts as an inhibitor will affect growth of transformed E. coli Sphi609 only. For this purpose, we compared the human and P. falciparum enzymes with known HGPRT substrate analogs. Our data with 6-mercaptopurine, 6-thioguanine and allopurinol show that these compounds act by being substrates for HGPRT. Our results with allopurinol suggest that it is a better substrate for P. falciparum HGXPRT than the human enzyme. Therefore, species-specific substrates can be tested out successfully in E. coli Sphi606. The formation of products from substrates like allopurinol lacking a labile proton at N7 raises the possibility that the deprotonation of substrates might occur at N9 rather than at N7 or a purine anion might be the true substrate for the reaction.

Changes in the natural history of progressive multifocal leukoencephalopathy in HIV-negative lymphoproliferative disorders: impact of novel therapies.

PubMed

García-Suárez, Julio; de Miguel, Dunia; Krsnik, Isabel; Bañas, Helena; Arribas, Ignacio; Burgaleta, Carmen

2005-12-01

The aims of this study were to evaluate the clinical characteristics of HIV-negative patients affected by lymphoproliferative disorders (LPD) who developed progressive multifocal leukoencephalopathy (PML), to delineate the risk factors, and to analyze whether the new antineoplastic therapies are changing the natural history of this infectious disease. We retrospectively analyzed 46 cases with confirmed LPD-associated PML published from 1958 to 2004. Patients were stratified according to two different time periods: group A included patients diagnosed before 1989, and group B included patients diagnosed since 1990, after introduction of purine analogues. Group A patients (n = 22) had received alkylating agents and/or radiotherapy, and the majority (63.6%) had advanced Hodgkin disease. At univariate analysis, uncontrolled Hodgkin disease was the only risk factor for PML. In group B patients (n = 24), the most frequent treatments received were purine analogues (58.3%) and high-dose therapy with hematopoietic stem cell transplantation (33.3%; HDT/HSCT). B-cell chronic lymphocytic leukemia (45.8%) and aggressive non-Hodgkin lymphoma (24.9%) were the most frequent underlying LPDs. Patients treated with purine analogues were more likely to have active LPD, lower CD4 cell counts, and to be older and male than were HSCT recipients. The median interval from purine analogues or HDT/HSCT to PML was 11 months. In HDT/HSCT recipients, this interval was delayed for 10 months when peri-transplantation rituximab was used. Univariate analysis identified age >55 years, male sex, and CD4 cell counts

Attempts to increase inosinic acid in broiler meat by using feed additives.

PubMed

Wang, X F; Liu, G H; Cai, H Y; Chang, W H; Ma, J S; Zheng, A J; Zhang, S

2014-11-01

To explore regulation of inosinic acid content in chicken meat as a result of feed additives, 576 one-day-old male Arbor Acres broilers were randomly allotted into 8 dietary treatments including control, purine nucleotide (P), betaine (B), soybean isoflavone (S), purine nucleotide + betaine (PB), purine nucleotide + soybean isoflavone (PS), betaine +soybean isoflavone (BS), and purine nucleotide + betaine + soybean isoflavone (PBS) by a 2 × 2 × 2 factorial arrangement. At d 42 of age, broilers were slaughtered, and growth performance, carcass characteristics, inosinic acid content, and activities of enzyme closely related to inosinic acid metabolism of broilers were measured. The results revealed that these feed additives did not affect ADG and ADFI of the broilers (P > 0.05). However, supplementing purine nucleotides lowered feed/gain of broilers in PS and PBS groups (P < 0.05). There was a significant interaction on feed/gain of broilers between purine nucleotides and soybean isoflavone (P < 0.05). The abdominal fat percentages in groups B, S, BS, and PBS were lower than the control group, respectively (P < 0.05). The thigh muscle percentages of groups P and B were higher than that of group PB (P < 0.05). There were certain interactions on the percentage of thigh muscle (P = 0.05) and abdominal fat (P < 0.05) between P, B, and S groups. Compared with the control group, inosinic acid content in broiler breast meat was improved by using feed additives (P < 0.05). Supplementing purine nucleotides, betaine, soybean isoflavone, and their combinations increased alkaline phosphatase activity in breast meat of broilers (P < 0.05). Purine nucleotides improved the activity of adenosine deaminase, but decreased the activity of 5'-nucleotidase. Soybean isoflavone lowered the activity of alkaline phosphatase. There were no significant interactions on activities of creatine kinase, adenosine deaminase, alkaline phosphatase, and 5'-nucleotidase between these additives (P > 0.05). The umami rating of broiler breast meat increased in conjunction with supplementing these additives. In conclusion, supplementing standard feed with the additives investigated in this study could improve inosinic acid content in chicken meat by increasing synthase activity or inhibiting degradation enzyme activity without inferior growth performance and carcass quality. ©2014 Poultry Science Association Inc.

Long-term exposure to diesel engine exhaust induces primary DNA damage: a population-based study.

PubMed

Duan, Huawei; Jia, Xiaowei; Zhai, Qingfeng; Ma, Lu; Wang, Shan; Huang, Chuanfeng; Wang, Haisheng; Niu, Yong; Li, Xue; Dai, Yufei; Yu, Shanfa; Gao, Weimin; Chen, Wen; Zheng, Yuxin

2016-02-01

Diesel engine exhaust (DEE) is a ubiquitous environmental pollutant and is carcinogenic to humans. To seek early and sensitive biomarkers for prediction of adverse health effects, we analysed the components of DEE particles, and examined the genetic and oxidative damages in DEE-exposed workers. 101 male diesel engine testing workers who were constantly exposed to DEE and 106 matched controls were enrolled in the present study. The components of DEE were analysed, including fine particulate matter (PM2.5), element carbon (EC), nitrogen dioxide (NO2), sulfur dioxide (SO2) and polycyclic aromatic hydrocarbons (PAHs). Postshift urine samples were collected and analysed for 1-hydroxypyrene (1-OHP), an internal exposure marker for DEE. Levels of DNA strand breaks and oxidised purines, defined as formamidopyrimidine-DNA glycosylase (FPG) sites in leucocytes, were measured by medium throughput Comet assay. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) was also used to determine the level of oxidative stress. We found higher levels of PM2.5, EC, NO2, SO2 and PAHs in the diesel engine testing workshop and significantly higher urinary 1-OHP concentrations in exposed subjects (p<0.001). Compared with controls, the levels of parameters in normal Comet and FPG-Comet assay were all significantly higher in DEE-exposed workers (p<0.001), and in a dose-dependent and time-dependent manner. There were no significant differences between DEE-exposed workers and controls in regard to leucocyte FPG sensitive sites and urinary 8-OHdG levels. These findings suggest that DEE exposure mainly induces DNA damage, which might be used as an early biomarker for risk assessment of DEE exposure. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Selective delivery of 2-hydroxy APA to Trypanosoma brucei using the melamine motif

PubMed Central

Klee, Nina; Wong, Pui Ee; Baragaña, Beatriz; Mazouni, Farah El; Phillips, Margaret A.; Barrett, Michael P.; Gilbert, Ian H.

2010-01-01

Trypanosoma brucei, the parasite that causes human African trypanosomiasis, is auxotrophic for purines and has specialist nucleoside transporters to import these metabolites. In particular, the P2 aminopurine transporter can also selectively accumulate melamine derivatives. In this Letter, we report the coupling of the melamine moiety to 2-hydroxy APA, a potent ornithine decarboxylase inhibitor, with the aim of selectively delivering this compound to the parasite. The best compound described here shows an increased in vitro trypanocidal activity compared with the parent. PMID:20615694

Origin of Urinary Oxalate

NASA Astrophysics Data System (ADS)

Holmes, Ross P.; Knight, John; Assimos, Dean G.

2007-04-01

Urinary oxalate is mostly derived from the absorption of ingested oxalate and endogenous synthesis. The breakdown of vitamin C may also contribute small amounts to the urinary oxalate pool. The amount of oxalate absorbed is influenced by the oxalate content of the diet, the concentrations of divalent cations in the gut, the presence of oxalate-degrading organisms, transport characteristics of the intestinal epithelium, and other factors associated with the intestinal environment. Knowledge of pathways associated with endogenous oxalate synthesis is limited. Urinary oxalate excretion can be modified using strategies that limit dietary oxalate absorption and the ingestion of oxalogenic substrates such as hydroxyproline.

Airway purinergic responses in healthy, atopic nonasthmatic, and atopic asthmatic subjects exposed to ozone**

EPA Science Inventory

Context: Ozone exposure triggers airway inflammatory responses that maybe influenced bybiologically active purine metabolites. Objective:To examinethe relationships between airway purine metabolites and established inflammatory markers of ozone exposure, and to determine if thes...

Parallel Prebiotic Origin of Canonical and Non-Canonical Purine Nucleosides

NASA Astrophysics Data System (ADS)

Becker, S.; Carell, T.

2017-07-01

RNA of all living organisms is highly modified. It is unclear if these non-canonical bases are ancestors of an early Earth or biological inventions. We investigated a prebiotic pathway that leads to canonical and non-canonical purine nucleosides.

Four new 6-oxy purine alkaloids from the South China Sea sponge, Haliclona cymaeformis

NASA Astrophysics Data System (ADS)

Chen, Min; Wu, Xudong; Shen, Nanxing; Wang, Changyun

2017-12-01

In this study, the chemical analysis of the marine sponge spieces, Haliclona cymaeformis, collected from the South China Sea was carried out, Two pairs of regioisomers of alkyl substitutional 6-oxy purine alkaloids ( 1a/ 1b and 2a/ 2b) were isolated. All of them possess two structural moieties, a 6-oxy purine nucleus and a pentan-2-one or hexan-2-one alkyl chain. Among them, 1a and 2a are the major N-9-substitutional regioisomers, and 1b and 2b are the minor N-7-substitutional regioisomers.

Changes in Purines Concentration in the Cerebrospinal Fluid of Pregnant Women Experiencing Pain During Active Labor.

PubMed

Schmidt, André P; Böhmer, Ana E; Hansel, Gisele; Soares, Félix A; Oses, Jean P; Giordani, Alex T; Posso, Irimar P; Auler, José Otávio C; Mendes, Florentino F; Félix, Elaine A; Portela, Luís V; Souza, Diogo O

2015-11-01

Labor pain has been reported as a severe pain and can be considered as a model of acute visceral pain. It is well known that extracellular purines have an important role in pain signaling in the central nervous system. This study analyzes the relationship between extracellular purines and pain perception during active labor. A prospective observational study was performed. Cerebrospinal fluid (CSF) levels of the purines and their metabolites were compared between women at term pregnancy with labor pain (n = 49) and without labor pain (Caesarian section; n = 47). Control groups (healthy men and women without chronic or acute pain-n = 40 and 32, respectively) were also investigated. The CSF levels of adenosine were significantly lower in the labor pain group (P = 0.026) and negatively correlated with pain intensity measured by a visual analogue scale (r = -0.48, P = 0.0005). Interestingly, CSF levels of uric acid were significantly higher in healthy men as compared to women. Additionally, pregnant women showed increased CSF levels of ADP, GDP, adenosine and guanosine and reduced CSF levels of AMP, GTP, and uric acid as compared to non-pregnant women (P < 0.05). These findings suggest that purines, in special the nucleoside adenosine, are associated with pregnancy and labor pain.

Distinct Distribution of Purines in CM and CR Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Callahan, Michael P.; Stern, Jennifer C.; Glavin, Daniel P.; Smith, Karen E.; Martin, Mildred G.; Dworkin, Jason P.

2010-01-01

Carbonaceous meteorites contain a diverse suite of organic molecules and delivered pre biotic organic compounds, including purines and pyrimidines, to the early Earth (and other planetary bodies), seeding it with the ingredients likely required for the first genetic material. We have investigated the distribution of nucleobases in six different CM and CR type carbonaceous chondrites, including fivc Antarctic meteorites never before analyzed for nucleobases. We employed a traditional formic acid extraction protocol and a recently developed solid phase extraction method to isolate nucleobases. We analyzed these extracts by high performance liquid chromatography with UV absorbance detection and tandem mass spectrometry (HPLC-UV -MS/MS) targeting the five canonical RNAIDNA bases and hypoxanthine and xanthine. We detected parts-per-billion levels of nucleobases in both CM and CR meteorites. The relative abundances of the purines found in Antarctic CM and CR meteorites were clearly distinct from each other suggesting that these compounds are not terrestrial contaminants. One likely source of these purines is formation by HCN oligomerization (with other small molecules) during aqueous alteration inside the meteorite parent body. The detection of the purines adenine (A), guanine (0), hypoxanthine (HX), and xanthine (X) in carbonaceous meteorites indicates that these compounds should have been available on the early Earth prior to the origin of the first genetic material.

Imidazopyridine- and purine-thioacetamide derivatives: potent inhibitors of nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1).

PubMed

Chang, Lei; Lee, Sang-Yong; Leonczak, Piotr; Rozenski, Jef; De Jonghe, Steven; Hanck, Theodor; Müller, Christa E; Herdewijn, Piet

2014-12-11

Nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) belongs to the family of ecto-nucleotidases, which control extracellular nucleotide, nucleoside, and (di)phosphate levels. To study the (patho)physiological roles of NPP1 potent and selective inhibitors with drug-like properties are required. Therefore, a compound library was screened for NPP1 inhibitors using a colorimetric assay with p-nitrophenyl 5'-thymidine monophosphate (p-Nph-5'-TMP) as an artificial substrate. This led to the discovery of 2-(3H-imidazo[4,5-b]pyridin-2-ylthio)-N-(3,4-dimethoxyphenyl)acetamide (5a) as a hit compound with a Ki value of 217 nM. Subsequent structure-activity relationship studies led to the development of purine and imidazo[4,5-b]pyridine analogues with high inhibitory potency (Ki values of 5.00 nM and 29.6 nM, respectively) when assayed with p-Nph-5'-TMP as a substrate. Surprisingly, the compounds were significantly less potent when tested versus ATP as a substrate, with Ki values in the low micromolar range. A prototypic inhibitor was investigated for its mechanism of inhibition and found to be competitive versus both substrates.

Adenosine metabolism in Toxoplasma gondii: potential targets for chemotherapy.

PubMed

el Kouni, Mahmoud H

2007-01-01

Toxoplasma gondii is an intracellular parasitic protozoan that infects approximately a billion people worldwide. Infection with T. gondii represents a major health problem for immunocompromised individuals, such as AIDS patients, organ transplant recipients, and the unborn children of infected mothers. Currently available drugs usually do not eradicate infection and as many as 50% of the patients do not respond to this therapy. Furthermore, they are ineffective against T. gondii tissue cysts. In addition, prolonged exposure to these drugs induces serious host toxicity forcing the discontinuation of the therapy. Finally, there is no effective vaccine currently available for the treatment of toxoplasmosis. Therefore, it is necessary to develop new and effective drugs for the treatment and management of toxoplasmosis. The rational design of a drug depends on the exploitation of fundamental biochemical or physiological differences between pathogens and their host. Some of the most striking differences between T. gondii and their mammalian host are found in purine metabolism. T. gondii, like most parasites studied, lack the ability to synthesize purines do novo and depend on the salvage of purines from their host to satisfy their requirements of purines. In this respect, the salvage of adenosine is the major source of purines in T. gondii. Therefore, interference with adenosine uptake and metabolism in T. gondii can be selectively detrimental to the parasite. The host cells, on the other hand, can still obtain their purine requirements by their de novo pathways. This review will focus on the broad aspects of the adenosine transport and the enzyme adenosine kinase (EC 2.7.1.20) which are the two primary routes for adenosine utilization in T. gondii, in an attempt to illustrate their potentials as targets for chemotherapy against this parasite.

Quantitation of intracellular purine intermediates in different Corynebacteria using electrospray LC-MS/MS.

PubMed

Peifer, Susanne; Schneider, Konstantin; Nürenberg, Gudrun; Volmer, Dietrich A; Heinzle, Elmar

2012-11-01

Intermediates of the purine biosynthesis pathway play key roles in cellular metabolism including nucleic acid synthesis and signal mediation. In addition, they are also of major interest to the biotechnological industry as several intermediates either possess flavor-enhancing characteristics or are applied in medical therapy. In this study, we have developed an analytical method for quantitation of 12 intermediates from the purine biosynthesis pathway including important nucleotides and their corresponding nucleosides and nucleobases. The approach comprised a single-step acidic extraction/quenching procedure, followed by quantitative electrospray LC-MS/MS analysis. The assay was validated in terms of accuracy, precision, reproducibility, and applicability for complex biological matrices. The method was subsequently applied for determination of free intracellular pool sizes of purine biosynthetic pathway intermediates in the two Gram-positive bacteria Corynebacterium glutamicum and Corynebacterium ammoniagenes. Importantly, no ion pair reagents were applied in this approach as usually required for liquid chromatography analysis of large classes of diverse metabolites.

Functional specialization of one copy of glutamine phosphoribosyl pyrophosphate amidotransferase in ureide production from symbiotically fixed nitrogen in Phaseolus vulgaris.

PubMed

Coleto, Inmaculada; Trenas, Almudena T; Erban, Alexander; Kopka, Joachim; Pineda, Manuel; Alamillo, Josefa M

2016-08-01

Purines are essential molecules formed in a highly regulated pathway in all organisms. In tropical legumes, the nitrogen fixed in the nodules is used to generate ureides through the oxidation of de novo synthesized purines. Glutamine phosphoribosyl pyrophosphate amidotransferase (PRAT) catalyses the first committed step of de novo purine synthesis. In Phaseolus vulgaris there are three genes coding for PRAT. The three full-length sequences, which are intron-less genes, were cloned, and their expression levels were determined under conditions that affect the synthesis of purines. One of the three genes, PvPRAT3, is highly expressed in nodules and protein amount and enzymatic activity in these tissues correlate with nitrogen fixation activity. Inhibition of PvPRAT3 gene expression by RNAi-silencing and subsequent metabolomic analysis of the transformed roots shows that PvPRAT3 is essential for the synthesis of ureides in P. vulgaris nodules. © 2016 John Wiley & Sons Ltd.

Growth in rice cells requires de novo purine biosynthesis by the blast fungus Magnaporthe oryzae

PubMed Central

Fernandez, Jessie; Yang, Kuan Ting; Cornwell, Kathryn M.; Wright, Janet D.; Wilson, Richard A.

2013-01-01

Increasing incidences of human disease, crop destruction and ecosystem perturbations are attributable to fungi and threaten socioeconomic progress and food security on a global scale. The blast fungus Magnaporthe oryzae is the most devastating pathogen of cultivated rice, but its metabolic requirements in the host are unclear. Here we report that a purine-requiring mutant of M. oryzae could develop functional appressoria, penetrate host cells and undergo the morphogenetic transition to elaborate bulbous invasive hyphae from primary hyphae, but further in planta growth was aborted. Invasive hyphal growth following rice cell ingress is thus dependent on de novo purine biosynthesis by the pathogen and, moreover, plant sources of purines are neither available to the mutant nor required by the wild type during the early biotrophic phase of infection. This work provides new knowledge about the metabolic interface between fungus and host that might be applicable to other important intracellular fungal pathogens. PMID:23928947

MTH1, an oxidized purine nucleoside triphosphatase, prevents the cytotoxicity and neurotoxicity of oxidized purine nucleotides.

PubMed

Nakabeppu, Yusaku; Kajitani, Kosuke; Sakamoto, Katsumi; Yamaguchi, Hiroo; Tsuchimoto, Daisuke

2006-07-13

In human and rodent cells, MTH1, an oxidized purine nucleoside triphosphatase, efficiently hydrolyzes oxidized dGTP, GTP, dATP and ATP such as 2'-deoxy-8-oxoguanosine triphosphate (8-oxo-dGTP) and 2'-deoxy-2-hydroxyadenosine triphosphate (2-OH-dATP) in nucleotide pools, thus avoiding their incorporation into DNA or RNA. MTH1 is expressed in postmitotic neurons as well as in proliferative tissues, and it is localized both in the mitochondria and nucleus, thus suggesting that MTH1 plays an important role in the prevention of the mutagenicity and cytotoxicity of such oxidized purines as 8-oxoG which are known to accumulate in the cellular genome. Our recent studies with MTH1-deficient mice or cells revealed that MTH1 efficiently minimizes accumulation of 8-oxoG in both nuclear and mitochondrial DNA in the mouse brain as well as in cultured cells, thus contributing to the protection of the brain from oxidative stress.

Characterization of Stevia leaves by LC-QTOF MS/MS analysis of polar and non-polar extracts.

PubMed

Molina-Calle, M; Priego-Capote, F; Luque de Castro, M D

2017-03-15

Stevia is currently a well-known plant thanks to its sweeting power. Numerous studies that elucidate its composition were exclusively focused on determination of steviol and its glycosides. Untargeted analysis was applied to obtain a profile of main compounds present in extracts from Stevia (Stevia rebaudiana Bertoni) leaves using LC-MS in high resolution mode with a quadrupole-time of flight analyzer. Eighty-nine compounds were tentatively identified and classified into different families: flavonoids; quinic and caffeic acids and derivatives; diterpenoids (including steviol and glycosides); sesquiterpenoids; amino acids and derivatives; fatty amides and derivatives; fatty acids and derivatives; oligosaccharides; glycerolipids; purines; and retinoids. New steviol glycosides were tentatively identified and their possible structures proposed. Other compounds were tentatively identified in Stevia for the first time, such as fatty acid amides. These results reveal the wide range of compounds present in Stevia, which could be responsible for the nutraceutical effects ascribed to their leaves. Copyright © 2016 Elsevier Ltd. All rights reserved.

Patterns of purine nucleotides in fish erythrocytes.

PubMed

Leray, C

1979-01-01

1. The purine nucleotides were determined in the whole blood of 9 fresh water teleosts and 2 marine selachians. 2. GTP and ATP accounted for 88-99% of the total erythrocytes purines. 3. The ATP/ADP ratio ranged from 11 to 60 in the erythrocytes of the fish examined. 4. GTP is widely distributed in fish erythrocytes but its level ranged from 1 to 33 nmol/mg Hb (0.4 to 9 mumol/ml erythrocyte). 5. Lepomis and Esox exhibited a GTP/ATP ratio as elevated as in Anguilla; moreover the concentration of GTP per mol of Hb (physiologically most indicative) is higher in Lepomis, Esox, Ictalurus and Silurus than in Anguilla.

3-(2-Benzofuranyl)quinuclidin-2-ene derivatives: novel muscarinic antagonists.

PubMed

Nordvall, G; Sundquist, S; Johansson, G; Glas, G; Nilvebrant, L; Hacksell, U

1996-08-16

A series of 26 derivatives of the novel muscarinic antagonist 3-(2-benzofuranyl)quinuclidin-2-ene (1) has been synthesized and evaluated for muscarinic and antimuscarinic properties. The affinity of the compounds was determined by competition experiments in homogenates of cerebral cortex, heart, parotid gland, and urinary bladder from guinea pigs using (-)-[3H]-3-quinuclidinyl benzilate as the radioligand, and the antimuscarinic-potency was determined in a functional assay on isolated guinea pig urinary bladder using carbachol as the agonist. The 5-fluorobenzofuranyl derivative was slightly more potent than 1. The 7-bromo-substituted 8 displayed a 14-fold tissue selectivity ratio for muscarinic receptors in the cortex versus the parotid gland. Comparative molecular field analysis and quantitative structure-activity relationship models were developed for this series of substituted benzofuranyl derivatives.

The high stability of the triple helices formed between short purine oligonucleotides and SIV/HIV-2 vpx genes is determined by the targeted DNA structure.

PubMed Central

Svinarchuk, F; Monnot, M; Merle, A; Malvy, C; Fermandjian, S

1995-01-01

In our previous works we have shown that the oligonucleotides 5'-GGGGAGGGGGAGG-3' and 5'-GGAGGGGGAGGGG-3' give very stable and specific triplexes with their target double stranded DNAs [Svinarchuk, F., Bertrand, J.-R. and Malvy, C. (1994) Nucleic Acids Res., 22, 3742-3747; Svinarchuk, F., Paoletti, J. and Malvy, C. (1995) J. Biol. Chem., 270, 14 068-14,071]. The target for the invariable part of these oligonucleotides, 5'-GGAGGGGGAGG-3', is found in a highly conserved 20 bp long purine/pyrimidine tract of the vpx gene of the SIV and HIV-2 viruses and could be a target for oligonucleotide directed antivirus therapy. Here were report on the ability of four purine oligonucleotides with different lengths (11-, 14-, 17- and 20-mer) to form triplexes with the purine/pyrimidine stretch of the vpx gene. Triplex formation was tested by joint dimethyl sulfate (DMS) footprint, gel-retardation assay, circular dichroism (CD) and UV-melting studies. Dimethyl sulfate footprint studies revealed the antiparallel orientation of the third strand to the purine strand of the Watson-Crick duplex. However, the protection of the guanines at the ends of the target sequence decreased as the length of the third strand oligonucleotide increased. Melting temperature studies provided profiles with only one transition for all of the triplexes. The melting temperatures of the triplexes were found to be the same as for the targeted duplex in the case of the 11- and 14-mer third strands while for the 17- and 20-mer third strands the melting temperature of the triplexes were correspondingly 4 and 8 degrees C higher than for the duplex. Heating and cooling melting curves were reversible for all of the tested triplexes except one with the 20-mer third strand oligonucleotide. Circular dichroism spectra showed the ability of the target DNA to adopt an A-like DNA conformation. Upon triplex formation the A-DNA form becomes even more pronounced. This effect depends on the length of the third strand oligonucleotide: the CD spectrum shows a 'classical' A-DNA shape with the 20-mer. This is not observed with the purine/pyrimidine stretch of the HIV-1 DNA which keeps a B-like spectrum even after triplex formation. We suggest, that an A-like duplex DNA is required for the formation of a stable DNA purine(purine-pyrimidine) triplex. Images PMID:7479024

Purines and Neuronal Excitability: Links to the Ketogenic Diet

PubMed Central

Masino, SA; Kawamura, M; Ruskin, DN; Geiger, JD; Boison, D

2011-01-01

ATP and adenosine are purines that play dual roles in cell metabolism and neuronal signaling. Acting at the A1 receptor (A1R) subtype, adenosine acts directly on neurons to inhibit excitability and is a powerful endogenous neuroprotective and anticonvulsant molecule. Previous research showed an increase in ATP and other cell energy parameters when an animal is administered a ketogenic diet, an established metabolic therapy to reduce epileptic seizures, but the relationship among purines, neuronal excitability and the ketogenic diet was unclear. Recent work in vivo and in vitro tested the specific hypothesis that adenosine acting at A1Rs is a key mechanism underlying the success of ketogenic diet therapy and yielded direct evidence linking A1Rs to the antiepileptic effects of a ketogenic diet. Specifically, an in vitro mimic of a ketogenic diet revealed an A1R-dependent metabolic autocrine hyperpolarization of hippocampal neurons. In parallel, applying the ketogenic diet in vivo to transgenic mouse models with spontaneous electrographic seizures revealed that intact A1Rs are necessary for the seizure-suppressing effects of the diet. This is the first direct in vivo evidence linking A1Rs to the antiepileptic effects of a ketogenic diet. Other predictions of the relationship between purines and the ketogenic diet are discussed. Taken together, recent research on the role of purines may offer new opportunities for metabolic therapy and insight into its underlying mechanisms. PMID:21880467

Interplay between adenylate metabolizing enzymes and amp-activated protein kinase.

PubMed

Camici, Marcella; Allegrini, Simone; Tozzi, Maria Grazia

2018-05-18

Purine nucleotides are involved in a variety of cellular functions, such as energy storage and transfer, and signalling, in addition to being the precursors of nucleic acids and cofactors of many biochemical reactions. They can be generated through two separate pathways, the de novo biosynthesis pathway and the salvage pathway. De novo purine biosynthesis leads to the formation of IMP, from which the adenylate and guanylate pools are generated by two additional steps. The salvage pathways utilize hypoxanthine, guanine and adenine to generate the corresponding mononucleotides. Despite several decades of research on the subject, new and surprising findings on purine metabolism are constantly being reported, and some aspects still need to be elucidated. Recently, purine biosynthesis has been linked to the metabolic pathways regulated by AMP-activated protein kinase (AMPK). AMPK is the master regulator of cellular energy homeostasis, and its activity depends on the AMP:ATP ratio. The cellular energy status and AMPK activation are connected by AMP, an allosteric activator of AMPK. Hence, an indirect strategy to affect AMPK activity would be to target the pathways that generate AMP in the cell. Herein, we report an up-to-date review of the interplay between AMPK and adenylate metabolizing enzymes. Some aspects of inborn errors of purine metabolism are also discussed. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Development and Validation of a Simple High Performance Liquid Chromatography/UV Method for Simultaneous Determination of Urinary Uric Acid, Hypoxanthine, and Creatinine in Human Urine.

PubMed

Wijemanne, Nimanthi; Soysa, Preethi; Wijesundara, Sulochana; Perera, Hemamali

2018-01-01

Uric acid and hypoxanthine are produced in the catabolism of purine. Abnormal urinary levels of these products are associated with many diseases and therefore it is necessary to have a simple and rapid method to detect them. Hence, we report a simple reverse phase high performance liquid chromatography (HPLC/UV) technique, developed and validated for simultaneous analysis of uric acid, hypoxanthine, and creatinine in human urine. Urine was diluted appropriately and eluted with C-18 column 100 mm × 4.6 mm with a C-18 precolumn 25 mm × 4.6 mm in series. Potassium phosphate buffer (20 mM, pH 7.25) at a flow rate of 0.40 mL/min was employed as the solvent and peaks were detected at 235 nm. Tyrosine was used as the internal standard. The experimental conditions offered a good separation of analytes without interference of endogenous substances. The calibration curves were linear for all test compounds with a regression coefficient, r 2 > 0.99. Uric acid, creatinine, tyrosine, and hypoxanthine were eluted at 5.2, 6.1, 7.2, and 8.3 min, respectively. Intraday and interday variability were less than 4.6% for all the analytes investigated and the recovery ranged from 98 to 102%. The proposed HPLC procedure is a simple, rapid, and low cost method with high accuracy with minimum use of organic solvents. This method was successfully applied for the determination of creatinine, hypoxanthine, and uric acid in human urine.

Process for producing 8-fluoropurines

DOEpatents

Barrio, J.R.; Satyamurthy, N.; Namavari, M.; Phelps, M.E.

1999-01-19

An efficient, regio-controlled approach to the synthesis of 8-fluoropurines by direct fluorination of purines with dilute elemental fluorine, or acetyl hypofluorite, is provided. In a preferred embodiment, a purine compound is dissolved in a polar solvent and reacted with a dilute mixture of F{sub 2} in He or other inert gas.

Was adenine the first purine?

NASA Technical Reports Server (NTRS)

Schwartz, Alan W.; Bakker, C. G.

1989-01-01

Oligomerization of HCN (1 molar) in the presence of added formaldehyde (0.5 molar) produced an order of magnitude more 8-hydroxymethyladenine than adenine or any other biologically significant purine. This result suggests that on the prebiotic earth, nucleoside analogs may have been synthesized directly in more complex mixtures of HCN with other aldehydes.

40 CFR 721.4685 - Substituted purine metal salt (generic name).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted purine metal salt (generic name). 721.4685 Section 721.4685 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4685...

Isolation of Purines and Pyrimidines from the Murchison Meteorite Using Sublimation

NASA Technical Reports Server (NTRS)

Glavin, D. P.; Bada, J. L.

2004-01-01

The origin of life on Earth, and possibly on other planets such as Mars, would have required the presence of liquid water and a continuous supply of prebiotic organic compounds. The exogenous delivery of organic matter by asteroids, comets, and carbonaceous meteorites could have contributed to the early Earth s prebiotic inventory by seeding the planet with biologically important organic compounds. A wide variety of prebiotic organic compounds have previously been detected in the Murchison CM type carbonaceous chondrite including amino acids, purines and pyrimidines. These compounds dominate terrestrial biochemistry and are integral components of proteins, DNA and RNA. Several purines including adenine, guanine, hypoxanthine, and xanthine, as well as the pyrimidine uracil, have previously been detected in water or formic acid extracts of Murchison using ion-exclusion chromatography and ultraviolet spectroscopy. However, even after purification of these extracts, the accurate identification and quantification of nucleobases is difficult due to interfering UV absorbing compounds. In order to reduce these effects, we have developed an extraction technique using sublimation to isolate purines and pyrimidines from other non-volatile organic compounds in Murchison acid extracts.

[Purine and pyrimidine nucleoside phosphorylases - remarkable enzymes still not fully understood].

PubMed

Bzowska, Agnieszka

2015-01-01

Purine and pyrimidine nucleoside phosphorylases catalyze the reversible phosphorolytic cleavage of the glycosidic bond of purine and pyrimidine nucleosides, and are key enzymes of the nucleoside salvage pathway. This metabolic route is the less costly alternative to the de novo synthesis of nucleosides and nucleotides, supplying cells with these important building blocks. Interest in nucleoside phosphorylases is not only due to their important role in metabolism of nucleosides and nucleotides, but also due to the potential medical use of the enzymes (all phosphorylases in activating prodrugs - nucleoside and nucleic base analogs, high-molecular mass purine nucleoside phosphorylases in gene therapy of some solid tumors) and their inhibitors (as selective immunosuppressive, anticancer and antiparasitic agents, and preventing inactivation of other nucleoside drugs). Phosphorylases are also convenient tools for efficient enzymatic synthesis of otherwise inaccessible nucleoside analogues. In this paper the contribution of Professor David Shugar and some of his colleagues and coworkers in studies of these remarkable enzymes carried out over nearly 40 years is discussed on the background of global research in this field.

Profiles of phenolic compounds and purine alkaloids during the development of seeds of Theobroma cacao cv. Trinitario.

PubMed

Pereira-Caro, Gema; Borges, Gina; Nagai, Chifumi; Jackson, Mel C; Yokota, Takao; Crozier, Alan; Ashihara, Hiroshi

2013-01-16

Changes occurring in phenolic compounds and purine alkaloids, during the growth of seeds of cacao (Theobroma cacao) cv. Trinitario, were investigated using HPLC-MS/MS. Extracts of seeds with a fresh weight of 125, 700, 1550, and 2050 mg (stages 1-4, respectively) were analyzed. The phenolic compounds present in highest concentrations in developing and mature seeds (stages 3 and 4) were flavonols and flavan-3-ols. Flavan-3-ols existed as monomers of epicatechin and catechin and as procyanidins. Type B procyanidins were major components and varied from dimers to pentadecamer. Two anthocyanins, cyanidin-3-O-arabinoside and cyanidin-3-O-galactoside, along with the N-phenylpropernoyl-l-amino acids, N-caffeoyl-l-aspartate, N-coumaroyl-l-aspartate, N-coumaroyl-3-hydroxytyrosine (clovamide), and N-coumaroyltyrosine (deoxyclovamide), and the purine alkaloids theobromine and caffeine, were present in stage 3 and 4 seeds. Other purine alkaloids, such as theophylline and additional methylxanthines, did not occur in detectable quantities. Flavan-3-ols were the only components to accumulate in detectable quantities in young seeds at developmental stages 1 and 2.

Molecular dynamics studies of a hexameric purine nucleoside phosphorylase.

PubMed

Zanchi, Fernando Berton; Caceres, Rafael Andrade; Stabeli, Rodrigo Guerino; de Azevedo, Walter Filgueira

2010-03-01

Purine nucleoside phosphorylase (PNP) (EC.2.4.2.1) is an enzyme that catalyzes the cleavage of N-ribosidic bonds of the purine ribonucleosides and 2-deoxyribonucleosides in the presence of inorganic orthophosphate as a second substrate. This enzyme is involved in purine-salvage pathway and has been proposed as a promising target for design and development of antimalarial and antibacterial drugs. Recent elucidation of the three-dimensional structure of PNP by X-ray protein crystallography left open the possibility of structure-based virtual screening initiatives in combination with molecular dynamics simulations focused on identification of potential new antimalarial drugs. Most of the previously published molecular dynamics simulations of PNP were carried out on human PNP, a trimeric PNP. The present article describes for the first time molecular dynamics simulations of hexameric PNP from Plasmodium falciparum (PfPNP). Two systems were simulated in the present work, PfPNP in ligand free form, and in complex with immucillin and sulfate. Based on the dynamical behavior of both systems the main results related to structural stability and protein-drug interactions are discussed.

Genetic and physiological characterization of the purine salvage pathway in the archaebacterium Methanobacterium thermoautotrophicum Marburg.

PubMed Central

Worrell, V E; Nagle, D P

1990-01-01

The enzymes involved in the purine interconversion pathway of wild-type and purine analog-resistant strains of Methanobacterium thermoautotrophicum Marburg were assayed by radiometric and spectrophotometric methods. Wild-type cells incorporated labeled adenine, guanine, and hypoxanthine, whereas mutant strains varied in their ability to incorporate these bases. Adenine, guanine, hypoxanthine, and xanthine were activated by phosphoribosyltransferase activities present in wild-type cell extracts. Some mutant strains simultaneously lost the ability to convert both guanine and hypoxanthine to the respective nucleotide, suggesting that the same enzyme activates both bases. Adenosine, guanosine, and inosine phosphorylase activities were detected for the conversion of base to nucleoside. Adenine deaminase activity was detected at low levels. Guanine deaminase activity was not detected. Nucleoside kinase activities for the conversion of adenosine, guanosine, and inosine to the respective nucleotides were detected by a new assay. The nucleotide-interconverting enzymes AMP deaminase, succinyl-AMP synthetase, succinyl-AMP lyase, IMP dehydrogenase, and GMP synthetase were present in extracts; GMP reductase was not detected. The results indicate that this autotrophic methanogen has a complex system for the utilization of exogenous purines. PMID:2345148

Short communication: Relationship between urinary neutrophil gelatinase-associated lipocalin and noninfectious pyuria in dogs.

PubMed

Proverbio, D; Spada, E; Baggiani, L; Bagnagatti De Giorgi, G; Ferro, E; Martino, P A; Perego, R

2015-01-01

Neutrophil gelatinase-associated lipocalin (NGAL) is a neutrophil-derived protein whose concentration increases in plasma and urine with ongoing renal damage. Urinary leucocytes can be a potential source of urinary NGAL. The aim of this study is to investigate the effects of urinary neutrophil count and other urinary parameters on urinary NGAL values in urine with negative culture. Urinalysis, urine culture, and determination of urinary NGAL were performed on 33 clinically healthy nonproteinuric dogs with negative urinoculture. The median uNGAL concentration in dogs in this study population was 9.74 ng/mL (IQR 1.93-25.43 ng/mL). In samples with WBCs > 5 hpf (mean 15.9, 6-50 leucocytes/hpf), median uNGAL value was significantly higher than that in samples with WBCs < 5 hpf (mean 0.9, 0-3 leucocytes/hpf), (4.96 pg/mL (0.29-11.34) and 23.65 pg/mL (20.04-29.80), resp.; P = 0.0053). The severity of urinary pyuria and the UPC value were correlated with uNGAL concentration. The results of our study show that urinary NGAL concentration is correlated with WBCs number in urinary sediment of dogs with negative urinoculture. The present study suggests that noninfectious pyuria is significantly correlated with urinary NGAL values and might influence uNGAL values.

Purine ionotropic (P2X) receptors.

PubMed

Köles, L; Fürst, S; Illes, P

2007-01-01

Purinergic signaling is involved in the proper functioning of virtually all organs of the body. Although in some cases purines have a major influence on physiological functions (e.g. thrombocyte aggregation), more often they are just background modulators contributing to fine tuning of biological events. However, under pathological conditions, when a huge amount of adenosine 5'-triphosphate (ATP) can reach the extracellular space, their significance is increasing. ATP and its various degradation products activate membrane receptors divided into two main classes: the metabotropic P2Y and the ionotropic P2X family. This latter group, the purine ionotropic receptor, is the object of this review. After providing a description about the distribution and functional properties of P2X receptors in the body, their pharmacology will be summarized. In the second part of this review, the role of purines in those organ systems and body functions will be highlighted, where the (patho)physiological role of P2X receptors has been suggested or is even well established. Besides the regulation of organ systems, for instance in the cardiovascular, respiratory, genitourinary or gastrointestinal system, some special issues will also be discussed, such as the role of P2X receptors in pain, tumors, central nervous system (CNS) injury and embryonic development. Several examples will indicate that purine ionotropic receptors might serve as attractive targets for pharmacological interventions in various diseases, and that selective ligands for these receptors will probably constitute important future therapeutic tools in humans.

Antioxidant effect of naturally occurring xanthines on the oxidative damage of DNA bases

NASA Astrophysics Data System (ADS)

Vieira, A. J. S. C.; Telo, J. P.; Pereira, H. F.; Patrocínio, P. F.; Dias, R. M. B.

1999-01-01

The repair of the oxidised radicals of adenine and guanosine by several naturally occurring xanthines was studied. Each pair of DNA purine/xanthine was made to react with the sulphate radical and the decrease of the concentration of both compounds was measured by HPLC as a function of irradiation time. The results show that xanthine efficiently prevents the oxidation of the two DNA purines. Theophyline and paraxanthine repair the oxidised radical of adenine but not the one from guanosine. Theobromine and caffeine do not show any protecting effect. An order of the oxidation potentials of all the purines studied is proposed. La réparation des radicaux oxydés de l'adénine et de la guanosine par des xanthines naturelles a été étudiée en soumettant chaque paire base de l'ADN/xanthine à l'oxydation par le radical sulfate et en mesurant par HPLC la disparition des deux composés en fonction du temps d'irradiation. Les résultats montrent que la xanthine joue un rôle protecteur efficace contre l'oxydation des deux purines de l'ADN. La théophyline et la paraxanthine réparent le radical oxydé de l'adénine mais pas celui de la guanosine. La théobromine et la cafeíne n'ont pas d'effet protecteur. Un ordre de potentiels d'oxydation des purines étudiées est proposé.

Computer Simulations Reveal Substrate Specificity of Glycosidic Bond Cleavage in Native and Mutant Human Purine Nucleoside Phosphorylase.

PubMed

Isaksen, Geir Villy; Hopmann, Kathrin Helen; Åqvist, Johan; Brandsdal, Bjørn Olav

2016-04-12

Purine nucleoside phosphorylase (PNP) catalyzes the reversible phosphorolysis of purine ribonucleosides and 2'-deoxyribonucleosides, yielding the purine base and (2'-deoxy)ribose 1-phosphate as products. While this enzyme has been extensively studied, several questions with respect to the catalytic mechanism have remained largely unanswered. The role of the phosphate and key amino acid residues in the catalytic reaction as well as the purine ring protonation state is elucidated using density functional theory calculations and extensive empirical valence bond (EVB) simulations. Free energy surfaces for adenosine, inosine, and guanosine are fitted to ab initio data and yield quantitative agreement with experimental data when the surfaces are used to model the corresponding enzymatic reactions. The cognate substrates 6-aminopurines (inosine and guanosine) interact with PNP through extensive hydrogen bonding, but the substrate specificity is found to be a direct result of the electrostatic preorganization energy along the reaction coordinate. Asn243 has previously been identified as a key residue providing substrate specificity. Mutation of Asn243 to Asp has dramatic effects on the substrate specificity, making 6-amino- and 6-oxopurines equally good as substrates. The principal effect of this particular mutation is the change in the electrostatic preorganization energy between the native enzyme and the Asn243Asp mutant, clearly favoring adenosine over inosine and guanosine. Thus, the EVB simulations show that this particular mutation affects the electrostatic preorganization of the active site, which in turn can explain the substrate specificity.

Purines and neuronal excitability: links to the ketogenic diet.

PubMed

Masino, S A; Kawamura, M; Ruskin, D N; Geiger, J D; Boison, D

2012-07-01

ATP and adenosine are purines that play dual roles in cell metabolism and neuronal signaling. Acting at the A(1) receptor (A(1)R) subtype, adenosine acts directly on neurons to inhibit excitability and is a powerful endogenous neuroprotective and anticonvulsant molecule. Previous research showed an increase in ATP and other cell energy parameters when an animal is administered a ketogenic diet, an established metabolic therapy to reduce epileptic seizures, but the relationship among purines, neuronal excitability and the ketogenic diet was unclear. Recent work in vivo and in vitro tested the specific hypothesis that adenosine acting at A(1)Rs is a key mechanism underlying the success of ketogenic diet therapy and yielded direct evidence linking A(1)Rs to the antiepileptic effects of a ketogenic diet. Specifically, an in vitro mimic of a ketogenic diet revealed an A(1)R-dependent metabolic autocrine hyperpolarization of hippocampal neurons. In parallel, applying the ketogenic diet in vivo to transgenic mouse models with spontaneous electrographic seizures revealed that intact A(1)Rs are necessary for the seizure-suppressing effects of the diet. This is the first direct in vivo evidence linking A(1)Rs to the antiepileptic effects of a ketogenic diet. Other predictions of the relationship between purines and the ketogenic diet are discussed. Taken together, recent research on the role of purines may offer new opportunities for metabolic therapy and insight into its underlying mechanisms. Copyright © 2011 Elsevier B.V. All rights reserved.

Synthesis of novel (2R,4R)- and (2S,4S)-iso dideoxynucleosides with exocyclic methylene as potential antiviral agents.

PubMed

Yoo, Su Jeong; Kim, Hea Ok; Lim, Yoongho; Kim, Jeongmin; Jeong, Lak Shin

2002-01-01

Novel (2R,4R)- and (2S,4S)-iso dideoxynucleosides with exocyclic methylene have been designed and synthesized, based on the lead BMS-200475 (3) which exhibited potent anti-HBV activity. For the synthesis of D types of (2R,4R)-nucleosides, L-xylose was converted to the key intermediate 14. The intermediate 14 was converted to the uracil derivative 4a and the cytosine derivative 4b. Compound 14 was also converted to the purine derivatives such as adenine derivative 4c, hypoxanthine derivative 4d, and guanine derivative 4e. The corresponding L types of (2S,4S)-enantiomers were more efficiently synthesized from the commercially available 1,2-isopropylidene-D-xylose (20) than the synthetic method used in the synthesis of (2R,4R)-nucleosides. The key intermediate 25 was converted to the pyrimidine analogues 5a and 5b and the purine derivatives 5c, 5d, and 5e using the similar method used in the preparation of 4c, 4d, and 4e. The synthesized final (2R,4R)- and (2S,4S)-nucleosides were tested against several viruses such as HIV-1, HSV-1, HSV-2, HCMV and HBV. (2R,4R)-Adenine analogue 4c exhibited potent anti-HBV activity (EC(50)=1.5 microM in 2.2.15 cells) among compounds tested, while (2R,4R)-uracil derivative 4a was the most active against HCMV among compounds tested and (2R,4R)-adenine derivative 4c was found to be moderately active against the same virus. However, the corresponding (2S,4S)-isomers were found to be totally inactive against all tested viruses. Both (2R,4R)-adenine derivative 4c and (2S,4S)-adenine analogue 5c were totally resistant to the adenosine deaminase like iso-ddA (1). From the molecular modeling study the hydroxymethyl side chains of BMS-200475 (3) and 4c were almost overlapped, indicating that 4c may be suitable for phosphorylation by cellular kinases like the lead 3, but some discrepancy between two bases was observed, indicating why 4c is less potent against HBV than 3. It is concluded that discovery of (2R,4R)-adenine analogue 4c as potent anti-HBV agent suggested that the sugar moiety of this series can be regarded as a novel template for the development of new anti-HBV agent and oxygen atom can be acted as a bioisostere of C-OH.

Escherichia coli isolates from patients with bacteremic urinary tract infection are genetically distinct from those derived from sepsis following prostate transrectal biopsy.

PubMed

Dan, Michael; Yair, Yael; Samosav, Alex; Gottesman, Tamar; Yossepowitch, Orit; Harari-Schwartz, Orna; Tsivian, Alexander; Schreiber, Rachel; Gophna, Uri

2015-01-01

Transrectal ultrasound-guided (TRUS) prostate biopsy is a very common procedure that is generally considered relatively safe. However, severe sepsis can occur after TRUS prostate biopsies, with Escherichia coli being the predominant causative agent. A common perception is that the bacteria that cause post-TRUS prostate biopsy infections originate in the urinary tract, but this view has not been adequately tested. Yet other authors believe on the basis of indirect evidence that the pathogens are introduced into the bloodstream by the biopsy needle after passage through the rectal mucosa. We compared E. coli isolates from male patients with bacteremic urinary tract infection (B-UTI) to isolates of patients with post prostate biopsy sepsis (PPBS), in terms of their sequence types, determined by multi-locus sequence typing (MLST) and their virulence markers. B-UTI isolates were much richer in virulence genes than were PPBS isolates, supporting the hypothesis that E. coli causing PPBS derive directly from the rectum. Sequence type 131 (ST131) strains and related strain from the ST131 were common (>30%) among the E. coli isolates from PPBS patients as well as from B-UTI patients and all these strains expressed extended spectrum beta-lactamases. Our finding supports the hypothesis that E. coli causing PPBS derive directly from the rectum, bypassing the urinary tract, and therefore do not require many of the virulence capabilities necessary for an E. coli strain that must persist in the urinary tract. In light of the increasing prevalence of highly resistant E. coli strains, a new approach for prevention of PPBS is urgently required. Copyright © 2015. Published by Elsevier GmbH.

Elevated Airway Purines in COPD

PubMed Central

Lazaar, Aili L.; Bordonali, Elena; Qaqish, Bahjat; Boucher, Richard C.

2011-01-01

Background: Adenosine and related purines have established roles in inflammation, and elevated airway concentrations are predicted in patients with COPD. However, accurate airway surface purine measurements can be confounded by stimulation of purine release during collection of typical respiratory samples. Methods: Airway samples were collected noninvasively as exhaled breath condensate (EBC) from 36 healthy nonsmokers (NS group), 28 healthy smokers (S group), and 89 subjects with COPD (29 with GOLD [Global Initiative for Chronic Obstructive Lung Disease] stage II, 29 with GOLD stage III, and 31 with GOLD stage IV) and analyzed with mass spectrometry for adenosine, adenosine monophosphate (AMP), and phenylalanine, plus urea as a dilution marker. Variable dilution of airway secretions in EBC was controlled using ratios to urea, and airway surface concentrations were calculated using EBC to serum urea-based dilution factors. Results: EBC adenosine to urea ratios were similar in NS (0.20 ± 0.21) and S (0.22 ± 0.20) groups but elevated in those with COPD (0.32 ± 0.30, P < .01 vs NS). Adenosine to urea ratios were highest in the most severely affected cohort (GOLD IV, 0.35 ± 0.34, P < .01 vs NS) and negatively correlated with FEV1 (r = −0.27, P < .01). Elevated AMP to urea ratios were also observed in the COPD group (0.58 ± 0.97 COPD, 0.29 ± 0.35 NS, P < .02), but phenylalanine to urea ratios were similar in all groups. Airway surface adenosine concentrations calculated in a subset of subjects were 3.2 ± 2.7 μM in those with COPD (n = 28) relative to 1.7 ± 1.5 μM in the NS group (n = 16, P < .05). Conclusions: Airway purines are present on airway surfaces at physiologically significant concentrations, are elevated in COPD, and correlate with markers of COPD severity. Purinergic signaling pathways are potential therapeutic targets in COPD, and EBC purines are potential noninvasive biomarkers. PMID:21454402

Hypoxia modulates the purine salvage pathway and decreases red blood cell and supernatant levels of hypoxanthine during refrigerated storage.

PubMed

Nemkov, Travis; Sun, Kaiqi; Reisz, Julie A; Song, Anren; Yoshida, Tatsuro; Dunham, Andrew; Wither, Matthew J; Francis, Richard O; Roach, Robert C; Dzieciatkowska, Monika; Rogers, Stephen C; Doctor, Allan; Kriebardis, Anastasios; Antonelou, Marianna; Papassideri, Issidora; Young, Carolyn T; Thomas, Tiffany A; Hansen, Kirk C; Spitalnik, Steven L; Xia, Yang; Zimring, James C; Hod, Eldad A; D'Alessandro, Angelo

2018-02-01

Hypoxanthine catabolism in vivo is potentially dangerous as it fuels production of urate and, most importantly, hydrogen peroxide. However, it is unclear whether accumulation of intracellular and supernatant hypoxanthine in stored red blood cell units is clinically relevant for transfused recipients. Leukoreduced red blood cells from glucose-6-phosphate dehydrogenase-normal or -deficient human volunteers were stored in AS-3 under normoxic, hyperoxic, or hypoxic conditions (with oxygen saturation ranging from <3% to >95%). Red blood cells from healthy human volunteers were also collected at sea level or after 1-7 days at high altitude (>5000 m). Finally, C57BL/6J mouse red blood cells were incubated in vitro with 13 C 1 -aspartate or 13 C 5 -adenosine under normoxic or hypoxic conditions, with or without deoxycoformycin, a purine deaminase inhibitor. Metabolomics analyses were performed on human and mouse red blood cells stored for up to 42 or 14 days, respectively, and correlated with 24 h post-transfusion red blood cell recovery. Hypoxanthine increased in stored red blood cell units as a function of oxygen levels. Stored red blood cells from human glucose-6-phosphate dehydrogenase-deficient donors had higher levels of deaminated purines. Hypoxia in vitro and in vivo decreased purine oxidation and enhanced purine salvage reactions in human and mouse red blood cells, which was partly explained by decreased adenosine monophosphate deaminase activity. In addition, hypoxanthine levels negatively correlated with post-transfusion red blood cell recovery in mice and - preliminarily albeit significantly - in humans. In conclusion, hypoxanthine is an in vitro metabolic marker of the red blood cell storage lesion that negatively correlates with post-transfusion recovery in vivo Storage-dependent hypoxanthine accumulation is ameliorated by hypoxia-induced decreases in purine deamination reaction rates. Copyright© 2018 Ferrata Storti Foundation.

Purines and Carotid Body: New Roles in Pathological Conditions

PubMed Central

Conde, Silvia V.; Monteiro, Emilia C.; Sacramento, Joana F.

2017-01-01

It is known that adenosine and adenosine-5′-triphosphate (ATP) are excitatory mediators involved in carotid body (CB) hypoxic signaling. The CBs are peripheral chemoreceptors classically defined by O2, CO2, and pH sensors. When hypoxia activates the CB, it induces the release of neurotransmitters from chemoreceptor cells leading to an increase in the action potentials frequency at the carotid sinus nerve (CSN). This increase in the firing frequency of the CSN is integrated in the brainstem to induce cardiorespiratory compensatory responses. In the last decade several pathologies, as, hypertension, diabetes, obstructive sleep apnea and heart failure have been associated with CB overactivation. In the first section of the present manuscript we review in a concise manner fundamental aspects of purine metabolism. The second section is devoted to the role of purines on the hypoxic response of the CB, providing the state-of-the art for the presence of adenosine and ATP receptors in the CB; for the role of purines at presynaptic level in CB chemoreceptor cells, as well as, its metabolism and regulation; at postsynaptic level in the CSN activity; and on the ventilatory responses to hypoxia. Recently, we have showed that adenosine is involved in CB hypersensitization during chronic intermittent hypoxia (CIH), which mimics obstructive sleep apnea, since caffeine, a non-selective adenosine receptor antagonist that inhibits A2A and A2B adenosine receptors, decreased CSN chemosensory activity in animals subjected to CIH. Apart from this involvement of adenosine in CB sensitization in sleep apnea, it was recently found that P2X3 ATP receptor in the CB contributes to increased chemoreflex hypersensitivity and hypertension in spontaneously hypertension rats. Therefore the last section of this manuscript is devoted to review the recent findings on the role of purines in CB-mediated pathologies as hypertension, diabetes and sleep apnea emphasizing the potential clinical importance of modulating purines levels and action to treat pathologies associated with CB dysfunction. PMID:29311923

T.C.G triplet in an antiparallel purine.purine.pyrimidine DNA triplex. Conformational studies by NMR.

PubMed

Dittrich, K; Gu, J; Tinder, R; Hogan, M; Gao, X

1994-04-12

The antiparallel purine.purine.pyrimidine DNA triplex, RRY6, which contains a T.C.G inverted triplet in the center of the sequence, was examined by proton and phosphorous two-dimensional NMR spectroscopy. The local conformation of the T.C.G triplet (T4.C11.G18) and the effect of this triplet on the global helical structure were analyzed in detail. The formation of the T.C.G triplet is confirmed by a set of cross-strand NOEs, including unusual cross-strand NOEs between the third strand and the pyrimidine strand as opposed to the purine strand of the duplex. NMR data suggest that the T.C.G triplet may be present in an equilibrium between a non-hydrogen-bonded form and a T(O4)-C(NH2) hydrogen-bonded form and that there is a distortion of the in-plane alignment of the three bases. The flanking G.G.C base triplets are well-defined on the 5'-side of T4, but somewhat interrupted on the 3'-side of T4. The effect of the third strand binding on the Watson-Crick duplex was probed by an NMR study of the free duplex RY6. NMR parameters are affected mostly around the T.C.G inversion site. The perturbations extend to at least two adjacent base triplets on either side. The binding of the third purine strand and the accommodation of a central T.C.G inversion in RRY6 does not require a readjustment in sugar pucker, which remains in the range of C2'-endo. 31P resonances of RRY6 distribute over a range of 2.2 ppm. The H-P coupling patterns of the third strand differ from those of the duplex. General spectral patterns defined by the marker protons of the RRY and YRY triplexes are compared.

Hypoxia modulates the purine salvage pathway and decreases red blood cell and supernatant levels of hypoxanthine during refrigerated storage

PubMed Central

Nemkov, Travis; Sun, Kaiqi; Reisz, Julie A.; Song, Anren; Yoshida, Tatsuro; Dunham, Andrew; Wither, Matthew J.; Francis, Richard O.; Roach, Robert C.; Dzieciatkowska, Monika; Rogers, Stephen C.; Doctor, Allan; Kriebardis, Anastasios; Antonelou, Marianna; Papassideri, Issidora; Young, Carolyn T.; Thomas, Tiffany A.; Hansen, Kirk C.; Spitalnik, Steven L.; Xia, Yang; Zimring, James C.; Hod, Eldad A.; D’Alessandro, Angelo

2018-01-01

Hypoxanthine catabolism in vivo is potentially dangerous as it fuels production of urate and, most importantly, hydrogen peroxide. However, it is unclear whether accumulation of intracellular and supernatant hypoxanthine in stored red blood cell units is clinically relevant for transfused recipients. Leukoreduced red blood cells from glucose-6-phosphate dehydrogenase-normal or -deficient human volunteers were stored in AS-3 under normoxic, hyperoxic, or hypoxic conditions (with oxygen saturation ranging from <3% to >95%). Red blood cells from healthy human volunteers were also collected at sea level or after 1–7 days at high altitude (>5000 m). Finally, C57BL/6J mouse red blood cells were incubated in vitro with 13C1-aspartate or 13C5-adenosine under normoxic or hypoxic conditions, with or without deoxycoformycin, a purine deaminase inhibitor. Metabolomics analyses were performed on human and mouse red blood cells stored for up to 42 or 14 days, respectively, and correlated with 24 h post-transfusion red blood cell recovery. Hypoxanthine increased in stored red blood cell units as a function of oxygen levels. Stored red blood cells from human glucose-6-phosphate dehydrogenase-deficient donors had higher levels of deaminated purines. Hypoxia in vitro and in vivo decreased purine oxidation and enhanced purine salvage reactions in human and mouse red blood cells, which was partly explained by decreased adenosine monophosphate deaminase activity. In addition, hypoxanthine levels negatively correlated with post-transfusion red blood cell recovery in mice and – preliminarily albeit significantly - in humans. In conclusion, hypoxanthine is an in vitro metabolic marker of the red blood cell storage lesion that negatively correlates with post-transfusion recovery in vivo. Storage-dependent hypoxanthine accumulation is ameliorated by hypoxia-induced decreases in purine deamination reaction rates. PMID:29079593

Therapies in early development for the treatment of urinary tract inflammation.

PubMed

Zacchè, Martino Maria; Giarenis, Ilias

2016-01-01

Urinary tract inflammation is a very common clinical condition. It is caused by several pathogens and antibiotic treatment is the mainstay of therapy. Increasing antimicrobial resistance and high recurrence rates represent a challenge. Consequently, there is an unmet need for new therapeutic options. The authors discuss the rationale of emerging management strategies and current experimentation. Furthermore, they focus on both acute and recurrent urinary tract infections (UTIs) and examine a range of therapeutics, including new antibiotics, vaccines, mannosides, hyaluronic acid, probiotics, immunomodulant agents and novel compounds derived from nanotechnology. Basic science studies have elucidated the pathogenesis of UTIs and built up the ground for the development of new therapies. Evidence is mainly derived from animal studies on murine models of bacterial cystitis. However, clinical trials are scanty and cannot provide us with robust evidence. Hetereogeneity and virulence of uropathogens pose a threat that scientists and clinicians are struggling to overcome.

Oral choline decreases brain purine levels in lithium-treated subjects with rapid-cycling bipolar disorder: a double-blind trial using proton and lithium magnetic resonance spectroscopy.

PubMed

Lyoo, In Kyoon; Demopulos, Christina M; Hirashima, Fuyuki; Ahn, Kyung Heup; Renshaw, Perry F

2003-08-01

Oral choline administration has been reported to increase brain phosphatidylcholine levels. As phospholipid synthesis for maintaining membrane integrity in mammalian brain cells consumes approximately 10-15% of the total adenosine triphosphate (ATP) pool, an increased availability of brain choline may lead to an increase in ATP consumption. Given reports of genetic studies, which suggest mitochondrial dysfunction, and phosphorus (31P) magnetic resonance spectroscopy (MRS) studies, which report dysfunction in high-energy phosphate metabolism in patients with bipolar disorder, the current study is designed to evaluate the role of oral choline supplementation in modifying high-energy phosphate metabolism in subjects with bipolar disorder. Eight lithium-treated patients with DSM-IV bipolar disorder, rapid cycling type were randomly assigned to 50 mg/kg/day of choline bitartrate or placebo for 12 weeks. Brain purine, choline and lithium levels were assessed using 1H- and 7Li-MRS. Patients received four to six MRS scans, at baseline and weeks 2, 3, 5, 8, 10 and 12 of treatment (n = 40 scans). Patients were assessed using the Clinical Global Impression Scale (CGIS), the Young Mania Rating Scale (YRMS) and the Hamilton Depression Rating Scale (HDRS) at each MRS scan. There were no significant differences in change-from-baseline measures of CGIS, YMRS, and HDRS, brain choline/creatine ratios, and brain lithium levels over a 12-week assessment period between the choline and placebo groups or within each group. However, the choline treatment group showed a significant decrease in purine metabolite ratios from baseline (purine/n-acetyl aspartate: coef = -0.08, z = -2.17, df = 22, p = 0.030; purine/choline: coef = -0.12, z = -1.97, df = 22, p = 0.049) compared to the placebo group, controlling for brain lithium level changes. Brain lithium level change was not a significant predictor of purine ratios. The current study reports that oral choline supplementation resulted in a significant decrease in brain purine levels over a 12-week treatment period in lithium-treated patients with DSM-IV bipolar disorder, rapid-cycling type, which may be related to the anti-manic effects of adjuvant choline. This result is consistent with mitochondrial dysfunction in bipolar disorder inadequately meeting the demand for increased ATP production as exogenous oral choline administration increases membrane phospholipid synthesis.

The conserved regulation of mitochondrial uncoupling proteins: From unicellular eukaryotes to mammals.

PubMed

Woyda-Ploszczyca, Andrzej M; Jarmuszkiewicz, Wieslawa

2017-01-01

Uncoupling proteins (UCPs) belong to the mitochondrial anion carrier protein family and mediate regulated proton leak across the inner mitochondrial membrane. Free fatty acids, aldehydes such as hydroxynonenal, and retinoids activate UCPs. However, there are some controversies about the effective action of retinoids and aldehydes alone; thus, only free fatty acids are commonly accepted positive effectors of UCPs. Purine nucleotides such as GTP inhibit UCP-mediated mitochondrial proton leak. In turn, membranous coenzyme Q may play a role as a redox state-dependent metabolic sensor that modulates the complete activation/inhibition of UCPs. Such regulation has been observed for UCPs in microorganisms, plant and animal UCP1 homologues, and UCP1 in mammalian brown adipose tissue. The origin of UCPs is still under debate, but UCP homologues have been identified in all systematic groups of eukaryotes. Despite the differing levels of amino acid/DNA sequence similarities, functional studies in unicellular and multicellular organisms, from amoebae to mammals, suggest that the mechanistic regulation of UCP activity is evolutionarily well conserved. This review focuses on the regulatory feedback loops of UCPs involving free fatty acids, aldehydes, retinoids, purine nucleotides, and coenzyme Q (particularly its reduction level), which may derive from the early stages of evolution as UCP first emerged. Copyright © 2016 Elsevier B.V. All rights reserved.

Degradation-by-design: Surface modification with functional substrates that enhance the enzymatic degradation of carbon nanotubes.

PubMed

Sureshbabu, Adukamparai Rajukrishnan; Kurapati, Rajendra; Russier, Julie; Ménard-Moyon, Cécilia; Bartolini, Isacco; Meneghetti, Moreno; Kostarelos, Kostas; Bianco, Alberto

2015-12-01

Biodegradation of carbon-based nanomaterials has been pursued intensively in the last few years, as one of the most crucial issues for the design of safe, clinically relevant conjugates for biomedical applications. In this paper it is demonstrated that specific functional molecules can enhance the catalytic activity of horseradish peroxidase (HRP) and xanthine oxidase (XO) for the degradation of carbon nanotubes. Two different azido coumarins and one cathecol derivative are linked to multi-walled carbon nanotubes (MWCNTs). These molecules are good reducing substrates and strong redox mediators to enhance the catalytic activity of HRP. XO, known to metabolize various molecules mainly in the mammalian liver, including human, was instead used to test the biodegradability of MWCNTs modified with an azido purine. The products of the biodegradation process are characterized by transmission electron microscopy and Raman spectroscopy. The results indicate that coumarin and catechol moieties have enhanced the biodegradation of MWCNTs compared to oxidized nanotubes, likely due to the capacity of these substrates to better interact with and activate HRP. Although azido purine-MWCNTs are degraded less effectively by XO than oxidized nanotubes, the data uncover the importance of XO in the biodegradation of carbon-nanomaterials leading to their better surface engineering for biomedical applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mg2+ ions: do they bind to nucleobase nitrogens?

PubMed Central

Leonarski, Filip; D'Ascenzo, Luigi; Auffinger, Pascal

2017-01-01

Given the many roles proposed for Mg2+ in nucleic acids, it is essential to accurately determine their binding modes. Here, we surveyed the PDB to classify Mg2+ inner-sphere binding patterns to nucleobase imine N1/N3/N7 atoms. Among those, purine N7 atoms are considered to be the best nucleobase binding sites for divalent metals. Further, Mg2+ coordination to N7 has been implied in several ribozyme catalytic mechanisms. We report that Mg2+ assigned near imine nitrogens derive mostly from poor interpretations of electron density patterns and are most often misidentified Na+, K+, NH4+ ions, water molecules or spurious density peaks. Consequently, apart from few documented exceptions, Mg2+ ions do not bind to N7 atoms. Without much of a surprise, Mn2+, Zn2+ and Cd2+, which have a higher affinity for nitrogens, may contact N7 atoms when present in crystallization buffers. In this respect, we describe for the first time a potential Zn2+ ribosomal binding site involving two purine N7 atoms. Further, we provide a set of guidelines to help in the assignment of Mg2+ in crystallographic, cryo-EM, NMR and model building practices and discuss implications of our findings related to ion substitution experiments. PMID:27923930

Serial Metabolome Changes in a Prospective Cohort of Subjects with Influenza Viral Infection and Comparison with Dengue Fever.

PubMed

Cui, Liang; Fang, Jinling; Ooi, Eng Eong; Lee, Yie Hou

2017-07-07

Influenza virus infection (IVI) and dengue virus infection (DVI) are major public health threats. Between IVI and DVI, clinical symptoms can be overlapping yet infection-specific, but host metabolome changes are not well-described. Untargeted metabolomics and targeted oxylipinomic analyses were performed on sera serially collected at three phases of infection from a prospective cohort study of adult subjects with either H3N2 influenza infection or dengue fever. Untargeted metabolomics identified 26 differential metabolites, and major perturbed pathways included purine metabolism, fatty acid biosynthesis and β-oxidation, tryptophan metabolism, phospholipid catabolism, and steroid hormone pathway. Alterations in eight oxylipins were associated with the early symptomatic phase of H3N2 flu infection, were mostly arachidonic acid-derived, and were enriched in the lipoxygenase pathway. There was significant overlap in metabolome profiles in both infections. However, differences specific to IVI and DVI were observed. DVI specifically attenuated metabolites including serotonin, bile acids and biliverdin. Additionally, metabolome changes were more persistent in IVI in which metabolites such as hypoxanthine, inosine, and xanthine of the purine metabolism pathway remained significantly elevated at 21-27 days after fever onset. This study revealed the dynamic metabolome changes in IVI subjects and provided biochemical insights on host physiological similarities and differences between IVI and DVI.

From Purines to Basic Biochemical Concepts: Experiments for High School Students

ERIC Educational Resources Information Center

Marini, Isabella; Ipata, Piero Luigi

2007-01-01

Many high school biology courses address mainly the molecular and cellular basis of life. The complexity that underlies the most essential processes is often difficult for the students to understand; possibly, in part, because of the inability to see and explore them. Six simple practical experiments on purine catabolism as a part of a…

Catalytic carbene transfer allows the direct customization of cyclic purine dinucleotides.

PubMed

Fei, Na; Häussinger, Daniel; Blümli, Seraina; Laventie, Benoît-Joseph; Bizzini, Lorenzo D; Zimmermann, Kaspar; Jenal, Urs; Gillingham, Dennis

2014-08-11

We describe a simple method for the direct modification of nucleobases in cyclic purine dinucleotides, important signalling molecules in both prokaryotes and eukaryotes. The method tolerates all members of the cyclic dinucleotide family and could be used to modulate their function or introduce useful side-chains such as fluorophores and photo-crosslinking groups.

Chiral symmetry breaking during the self-assembly of monolayers from achiral purine molecules.

PubMed

Sowerby, S J; Heckl, W M; Petersen, G B

1996-11-01

Scanning tunneling microscopy was used to investigate the structure of the two-dimensional adsorbate formed by molecular self-assembly of the purine base, adenine, on the surfaces of the naturally occurring mineral molybdenite and the synthetic crystal highly oriented pyrolytic graphite. Although formed from adenine, which is achiral, the observed adsorbate surface structures were enantiomorphic on molybdenite. This phenomenon suggests a mechanism for the introduction of a localized chiral symmetry break by the spontaneous crystallization of these prebiotically available molecules on inorganic surfaces and may have some role in the origin of biomolecular optical asymmetry. The possibility that purine-pyrimidine arrays assembled on naturally occurring mineral surfaces might act as possible templates for biomolecular assembly is discussed.

The Deoxynucleoside Triphosphate Triphosphohydrolase Activity of SAMHD1 Protein Contributes to the Mitochondrial DNA Depletion Associated with Genetic Deficiency of Deoxyguanosine Kinase*

PubMed Central

Franzolin, Elisa; Salata, Cristiano; Bianchi, Vera; Rampazzo, Chiara

2015-01-01

The dNTP triphosphohydrolase SAMHD1 is a nuclear antiviral host restriction factor limiting HIV-1 infection in macrophages and a major regulator of dNTP concentrations in human cells. In normal human fibroblasts its expression increases during quiescence, contributing to the small dNTP pool sizes of these cells. Down-regulation of SAMHD1 by siRNA expands all four dNTP pools, with dGTP undergoing the largest relative increase. The deoxyguanosine released by SAMHD1 from dGTP can be phosphorylated inside mitochondria by deoxyguanosine kinase (dGK) or degraded in the cytosol by purine nucleoside phosphorylase. Genetic mutations of dGK cause mitochondrial (mt) DNA depletion in noncycling cells and hepato-cerebral mtDNA depletion syndrome in humans. We studied if SAMHD1 and dGK interact in the regulation of the dGTP pool during quiescence employing dGK-mutated skin fibroblasts derived from three unrelated patients. In the presence of SAMHD1 quiescent mutant fibroblasts manifested mt dNTP pool imbalance and mtDNA depletion. When SAMHD1 was silenced by siRNA transfection the composition of the mt dNTP pool approached that of the controls, and mtDNA copy number increased, compensating the depletion to various degrees in the different mutant fibroblasts. Chemical inhibition of purine nucleoside phosphorylase did not improve deoxyguanosine recycling by dGK in WT cells. We conclude that the activity of SAMHD1 contributes to the pathological phenotype of dGK deficiency. Our results prove the importance of SAMHD1 in the regulation of all dNTP pools and suggest that dGK inside mitochondria has the function of recycling the deoxyguanosine derived from endogenous dGTP degraded by SAMHD1 in the nucleus. PMID:26342080

Identification of new aromatic cytokinins in Arabidopsis thaliana and Populus x canadensis leaves by LC-(+)ESI-MS and capillary liquid chromatography/frit-fast atom bombardment mass spectrometry.

PubMed

Tarkowská, Danuse; Dolezal, Karel; Tarkowski, Petr; Astot, Crister; Holub, Jan; Fuksová, Kvetoslava; Schmülling, Thomas; Sandberg, Göran; Strnad, Miroslav

2003-04-01

A search for naturally occurring aromatic cytokinins (ARCKs) in Arabidopsis thaliana plants and Populus x canadensis leaves led to the discovery of four new plant hormone substances: 6-(2-methoxybenzylamino)purine (ortho-methoxytopolin, MeoT), 6-(3-methoxybenzylamino)purine (meta-methoxytopolin, MemT) (Fig. 1) and their 9-beta-D-ribofuranosyl derivatives. These substances were identified by liquid chromatography electrospray ionization mass spectrometry [LC (+)ESI-MS] and capillary-liquid chromatography/frit-fast atom bombardment-mass spectrometry [CapLC/frit-FAB-MS] after pre-column derivatization. The chemical structures were subsequently confirmed by chemical synthesis. Because of lack of heavy labelled internal standards, the endogenous levels of methoxytopolins in A. thaliana plants, Populus x canadensis leaves and samples derived from cultures of Agrobacterium tumefaciens strain GV3101 were determined by enzyme-linked immunosorbent assay (ELISA) of HPLC-fractionated extracts. While the levels of MeoT, MemT and their ribosides in A. thaliana shoots and Populus x canadensis leaves were relatively low (approximately 0.25-10 pmol g-1 FW for MeoT and MemT, respectively), the A. tumefaciens strain produced up to 600 times more of the newly identified substances. Cytokinin activity of methoxytopolines was demonstrated in three bioassays testing their ability to stimulate tobacco callus growth, to delay chlorophyll degradation in excised wheat leaves, and to induce betacyanin synthesis in Amaranthus caudatus var. atropurpurea cotyledons. Notably, their anti-senescing activity in the wheat leaf assay exceeded that of BAP and Z by almost 200%. Methoxytopolins are proposed to be new members of the biologically active aromatic cytokinin family, which might have specific physiological functions.

Allopurinol-mediated lignocellulose-derived microbial inhibitor tolerance by Clostridium beijerinckii during acetone-butanol-ethanol (ABE) fermentation.

PubMed

Ujor, Victor; Agu, Chidozie Victor; Gopalan, Venkat; Ezeji, Thaddeus Chukwuemeka

2015-04-01

In addition to glucans, xylans, and arabinans, lignocellulosic biomass hydrolysates contain significant levels of nonsugar components that are toxic to the microbes that are typically used to convert biomass to biofuels and chemicals. To enhance the tolerance of acetone-butanol-ethanol (ABE)-generating Clostridium beijerinckii NCIMB 8052 to these lignocellulose-derived microbial inhibitory compounds (LDMICs; e.g., furfural), we have been examining different metabolic perturbation strategies to increase the cellular reductant pools and thereby facilitate detoxification of LDMICs. As part of these efforts, we evaluated the effect of allopurinol, an inhibitor of NAD(P)H-generating xanthine dehydrogenase (XDH), on C. beijerinckii grown in furfural-supplemented medium and found that it unexpectedly increased the rate of detoxification of furfural by 1.4-fold and promoted growth, butanol, and ABE production by 1.2-, 2.5-, and 2-fold, respectively. Since NAD(P)H/NAD(P)(+) levels in C. beijerinckii were largely unchanged upon allopurinol treatment, we postulated and validated a possible basis in DNA repair to account for the solventogenic gains with allopurinol. Following the observation that supplementation of allopurinol in the C. beijerinckii growth media mitigates the toxic effects of nalidixic acid, a DNA-damaging antibiotic, we found that allopurinol elicited 2.4- and 6.7-fold increase in the messenger RNA (mRNA) levels of xanthine and hypoxanthine phosphoribosyltransferases, key purine-salvage enzymes. Consistent with this finding, addition of inosine (a precursor of hypoxanthine) and xanthine led to 1.4- and 1.7-fold increase in butanol production in furfural-challenged cultures of C. beijerinckii. Taken together, our results provide a purine salvage-based rationale for the unanticipated effect of allopurinol in improving furfural tolerance of the ABE-fermenting C. beijerinckii.

Measurement of urinary metanephrines to screen for pheochromocytoma in an unselected hospital referral population.

PubMed

Brain, Keith L; Kay, Jonathan; Shine, Brian

2006-11-01

Despite the rarity of pheochromocytoma, diagnosis is important because of the dangers of uncontrolled severe hypertension and the availability of very effective surgical treatment. Urinary or plasma catecholamines or catecholamine derivatives are commonly used to screen for pheochromocytomas before imaging, but data from 24-h urinary metanephrine results, patient age, and sex may better predict tumors in populations with a low pretest probability. We retrospectively studied outcomes of an unselected population (1819 patients) referred to a tertiary hospital laboratory for urinary metanephrine testing and investigated the usefulness of some simple derivative measures for detecting pheochromocytoma. We normalized values for urinary 24-h excretion of metanephrine, normetanephrine, and 3-methoxytyramine by dividing by an age- and sex-specific reference range. We then compared pheochromocytoma prediction by the use of products of these normalized measures with the gold standard of biopsy-confirmed tumor. The product of the excretion of normalized metanephrine (nMAD) and normalized normetanephrine (nNMT) (nMAD.nNMT) was a highly sensitive (100%) and specific (99.1%) measure, yielding a positive predictive value of 82%. ROC curves were not improved by including the normalized 3-methoxytyramine concentrations in the product. The test for nMAD.nNMT gave higher sensitivity and specificity than the tests for either substance alone. The test for nMAD.nNMT is a useful measure for identifying pheochromocytoma in a population with a low pretest probability.

Comprehensive Metaproteomic Analyses of Urine in the Presence and Absence of Neutrophil-Associated Inflammation in the Urinary Tract

PubMed Central

Yu, Yanbao; Sikorski, Patricia; Smith, Madeline; Bowman-Gholston, Cynthia; Cacciabeve, Nicolas; Nelson, Karen E.; Pieper, Rembert

2017-01-01

Inflammation in the urinary tract results in a urinary proteome characterized by a high dynamic range of protein concentrations and high variability in protein content. This proteome encompasses plasma proteins not resorbed by renal tubular uptake, renal secretion products, proteins of immune cells and erythrocytes derived from trans-urothelial migration and vascular leakage, respectively, and exfoliating urothelial and squamous epithelial cells. We examined how such proteins partition into soluble urine (SU) and urinary pellet (UP) fractions by analyzing 33 urine specimens 12 of which were associated with a urinary tract infection (UTI). Using mass spectrometry-based metaproteomic approaches, we identified 5,327 non-redundant human proteins, 2,638 and 4,379 of which were associated with SU and UP fractions, respectively, and 1,206 non-redundant protein orthology groups derived from pathogenic and commensal organisms of the urogenital tract. Differences between the SU and UP proteomes were influenced by local inflammation, supported by respective comparisons with 12 healthy control urine proteomes. Clustering analyses showed that SU and UP fractions had proteomic signatures discerning UTIs, vascular injury, and epithelial cell exfoliation from the control group to varying degrees. Cases of UTI revealed clusters of proteins produced by activated neutrophils. Network analysis supported the central role of neutrophil effector proteins in the defense against invading pathogens associated with subsequent coagulation and wound repair processes. Our study expands the existing knowledge of the urinary proteome under perturbed conditions, and should be useful as reference dataset in the search of biomarkers. PMID:28042331

Meta-analysis for deriving age- and gender-specific dose-response relationships between urinary cadmium concentration and {beta} {sub 2}-microglobulinuria under environmental exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gamo, Masashi; Ono, Kyoko; Nakanishi, Junko

2006-05-15

A meta-analysis was conducted to derive age- and gender-specific dose-response relationships between urinary cadmium (Cd) concentration and {beta} {sub 2}-microglobulinuria ({beta}2MG-uria) under environmental exposure. {beta}2MG-uria was defined by a cutoff point of 1000 {mu}g {beta} {sub 2}-microglobulin/g creatinine. We proposed a model for describing the relationships among the interindividual variabilities in urinary Cd concentration, the ratio of Cd concentrations in the target organ and in urine, and the threshold Cd concentration in the target organ. The parameters in the model were determined so that good agreement might be achieved between the prevalence rates of {beta}2MG-uria reported in the literature andmore » those estimated by the model. In this analysis, only the data from the literature on populations environmentally exposed to Cd were used. Using the model and estimated parameters, the prevalence rate of {beta}2MG-uria can be estimated for an age- and gender-specific subpopulation for which the distribution of urinary Cd concentrations is known. The maximum permissible level of urinary Cd concentration was defined as the maximum geometric mean of the urinary Cd concentration in an age- and gender-specific subpopulation that would not result in a statistically significant increase in the prevalence rate of {beta}2MG-uria. This was estimated to be approximately 3 {mu}g/g creatinine for a population in a small geographical area and approximately 2 {mu}g/g creatinine for a nationwide population.« less

A PHGDH inhibitor reveals coordination of serine synthesis and 1-carbon unit fate

PubMed Central

Pacold, Michael E.; Brimacombe, Kyle R.; Chan, Sze Ham; Rohde, Jason M.; Lewis, Caroline A.; Swier, Lotteke J.Y.M.; Possemato, Richard; Chen, Walter W.; Sullivan, Lucas B.; Fiske, Brian P.; Cho, Sung Won; Freinkman, Elizaveta; Birsoy, Kıvanç; Abu-Remaileh, Monther; Shaul, Yoav D.; Liu, Chieh Min; Zhou, Minerva; Koh, Min Jung; Chung, Haeyoon; Davidson, Shawn M.; Luengo, Alba; Wang, Amy Q.; Xu, Xin; Yasgar, Adam; Liu, Li; Rai, Ganesha; Westover, Kenneth D.; Vander Heiden, Matthew G.; Shen, Min; Gray, Nathanael S.; Boxer, Matthew B.; Sabatini, David M.

2016-01-01

Serine is a both a proteinogenic amino acid and the source of one-carbon units essential for de novo purine and deoxythymidine synthesis. In the canonical glucose-derived serine synthesis pathway, Homo sapiens phosphoglycerate dehydrogenase (PHGDH) catalyzes the first, rate-limiting step. Genetic loss of PHGDH is toxic towards PHGDH-overexpressing breast cancer cell lines even in the presence of exogenous serine. Here, we use a quantitative high-throughput screen to identify small molecule PHGDH inhibitors. These compounds reduce the production of glucose-derived serine in cells and suppress the growth of PHGDH-dependent cancer cells in culture and in orthotopic xenograft tumors. Surprisingly, PHGDH inhibition reduced the incorporation into nucleotides of one-carbon units from glucose-derived and exogenous serine. We conclude that glycolytic serine synthesis coordinates the use of one-carbon units from endogenous and exogenous serine in nucleotide synthesis, and suggest that one-carbon unit wasting may contribute to the efficacy of PHGDH inhibitors in vitro and in vivo. PMID:27110680

Synthesis of 4'-Selenoribonucleosides, the Building Blocks of 4'-SelenoRNA, Using a Hypervalent Iodine.

PubMed

Saito-Tarashima, Noriko; Ota, Masashi; Minakawa, Noriaki

2017-09-18

Herein is described a detailed protocol for the synthesis of 4'-selenoribonucleoside derivatives that involves the use of a hypervalent iodine species. These derivatives are versatile units for the preparation of 4'-selenoRNA. Large-scale synthesis of a 4-selenosugar starting from D-ribose is achieved in eight steps, including a final chromatographic purification. The resulting 4-selenosugar is then subjected to the one-pot Pummerer-like reaction using hypervalent iodine in the presence of silylated nucleobases. The reaction with silylated uracil affords the desired 4'-selenouridine derivatives with excellent β-selectivity and in good yield. Conversely, when purine nucleobases are used in the Pummerer-like reaction, N7 4'-selenoribonucleoside isomers are obtained alongside the desired N9 isomers. However, the undesired N7 isomers can be converted to the desired N9 ones under acidic conditions. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

An in vitro analysis of purine-mediated renal vasoconstriction in rat isolated kidney.

PubMed Central

Kenakin, T. P.; Pike, N. B.

1987-01-01

In the rat isolated perfused kidney, 2-chloroadenosine and L-N6-phenyl-isopropyl adenosine (L-PIA) produced a modest vasodilatation. After kidneys had been pretreated with methoxamine (to elevate vascular tone) and forskolin (to activate adenyl cyclase and reduce vascular tone), both purine agonists produced vasoconstriction at low doses and vasodilatation at higher doses. This was consistent with the working hypothesis that vasoconstriction resulted from activation of A1-purinoceptors mediating adenyl cyclase inhibition and vasodilatation from activation of A2-purinoceptors stimulating adenyl cyclase. These kidney preparations also demonstrated a marked potentiation of purine-mediated vasoconstriction in the presence of various concentrations of 8-p-sulpho-phenyltheophylline (8-SPT), a drug reported in the literature to be a competitive antagonist of A1- and A2-purinoceptors. Maximal renal vasoconstriction to 2-chloroadenosine and L-PIA was observed in the presence of 10 mM 8-SPT; the fact that this vasoconstriction was sensitive to the selective A1-receptor antagonist 8-(2-amino-4-chlorophenyl)-1,3-dipropylxanthine (PACPX) and that the order of potency of agonists for this effect was L-PIA greater than 2-chloroadenosine greater than D-PIA greater than N6-ethylcarboxamide adenosine (NECA) was consistent with activation of vascular A1-purinoceptors. While these data are consistent with the hypothesis that purines activate vascular A1- and A2-receptors in the rat isolated kidney, the nature of the results did not allow definitive classification of the receptors mediating the purine effects. PMID:3828655

Murine lymphoma L5178Y cells resistant to purine antagonists: differences in cross-resistance to thioguanine-platinum(II) and selenoguanine-platinum(II).

PubMed

Kanzawa, F; Maeda, M; Sasaki, T; Hoshi, A; Kuretani, K

1982-02-01

To determine whether the antitumor activities of thioguanine-platinum(II) [TG-Pt(II)] and selenoguanine-platinum(II) [SeG-Pt(II)] are due to direct actions of these compounds or to the actions of their hydrolysis products, studies were made on a purine antagonist-resistant, murine lymphoma L5178Y/MP subline that lacked the anabolic enzyme hypoxanthine-guanine phosphoribosyltransferase necessary for tumor inhibition. The L5178Y/MP subline proved to be highly resistant to both TG-Pt(II) and thioguanine; the resistance ratios to the two compounds were almost identical. The subline showed high resistance to selenoguanine, but the cross-resistance to SeG-Pt(II) was negligible. Whether the compounds exhibit the delayed cytotoxicity characteristic of purine antagonists was also investigated. Delayed cytotoxicity was demonstrated for TG-Pt(II) as well as for thioguanine and other purine antagonists but not for SeG-Pt(II) or cis-dichlorodiammineplatinum(II). Experiments on cross-resistance and delayed cytotoxicity showed differences in the cytotoxicities of TG-Pt(II) and SeG-Pt(II): TG-Pt(II) exerted its activity through its hydrolysis product thioguanine, whereas SeG-Pt(II) compound was cytotoxic itself.

Structures of Substrate-And Inhibitor-Bound Adenosine Deaminase From a Human Malaria Parasite Show a Dramatic Conformational Change And Shed Light on Drug Selectivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larson, E.T.; Deng, W.; Krumm, B.E.

Plasmodium and other apicomplexan parasites are deficient in purine biosynthesis, relying instead on the salvage of purines from their host environment. Therefore, interference with the purine salvage pathway is an attractive therapeutic target. The plasmodial enzyme adenosine deaminase (ADA) plays a central role in purine salvage and, unlike mammalian ADA homologs, has a further secondary role in methylthiopurine recycling. For this reason, plasmodial ADA accepts a wider range of substrates, as it is responsible for deamination of both adenosine and 5{prime}-methylthioadenosine. The latter substrate is not accepted by mammalian ADA homologs. The structural basis for this natural difference in specificitymore » between plasmodial and mammalian ADA has not been well understood. We now report crystal structures of Plasmodium vivax ADA in complex with adenosine, guanosine, and the picomolar inhibitor 2{prime}-deoxycoformycin. These structures highlight a drastic conformational change in plasmodial ADA upon substrate binding that has not been observed for mammalian ADA enzymes. Further, these complexes illuminate the structural basis for the differential substrate specificity and potential drug selectivity between mammalian and parasite enzymes.« less

Altered Mitochondria, Protein Synthesis Machinery, and Purine Metabolism Are Molecular Contributors to the Pathogenesis of Creutzfeldt-Jakob Disease.

PubMed

Ansoleaga, Belén; Garcia-Esparcia, Paula; Llorens, Franc; Hernández-Ortega, Karina; Carmona Tech, Margarita; Antonio Del Rio, José; Zerr, Inga; Ferrer, Isidro

2016-06-12

Neuron loss, synaptic decline, and spongiform change are the hallmarks of sporadic Creutzfeldt-Jakob disease (sCJD), and may be related to deficiencies in mitochondria, energy metabolism, and protein synthesis. To investigate these relationships, we determined the expression levels of genes encoding subunits of the 5 protein complexes of the electron transport chain, proteins involved in energy metabolism, nucleolar and ribosomal proteins, and enzymes of purine metabolism in frontal cortex samples from 15 cases of sCJD MM1 and age-matched controls. We also assessed the protein expression levels of subunits of the respiratory chain, initiation and elongation translation factors of protein synthesis, and localization of selected mitochondrial components. We identified marked, generalized alterations of mRNA and protein expression of most subunits of all 5 mitochondrial respiratory chain complexes in sCJD cases. Expression of molecules involved in protein synthesis and purine metabolism were also altered in sCJD. These findings point to altered mRNA and protein expression of components of mitochondria, protein synthesis machinery, and purine metabolism as components of the pathogenesis of CJD. © 2016 American Association of Neuropathologists, Inc. All rights reserved.

A randomised cross-over pharmacokinetic bioavailability study of synthetic versus kiwifruit-derived vitamin C.

PubMed

Carr, Anitra C; Bozonet, Stephanie M; Vissers, Margreet C M

2013-11-11

Kiwifruit are a rich source of vitamin C and also contain numerous phytochemicals, such as flavonoids, which may influence the bioavailability of kiwifruit-derived vitamin C. The aim of this study was to compare the relative bioavailability of synthetic versus kiwifruit-derived vitamin C using a randomised cross-over pharmacokinetic study design. Nine non-smoking males (aged 18-35 years) received either a chewable tablet (200 mg vitamin C) or the equivalent dose from gold kiwifruit (Actinidia chinensis var. Sungold). Fasting blood and urine were collected half hourly to hourly over the eight hours following intervention. The ascorbate content of the plasma and urine was determined using HPLC with electrochemical detection. Plasma ascorbate levels increased from 0.5 h after the intervention (P = 0.008). No significant differences in the plasma time-concentration curves were observed between the two interventions (P = 0.645). An estimate of the total increase in plasma ascorbate indicated complete uptake of the ingested vitamin C tablet and kiwifruit-derived vitamin C. There was an increase in urinary ascorbate excretion, relative to urinary creatinine, from two hours post intervention (P < 0.001). There was also a significant difference between the two interventions, with enhanced ascorbate excretion observed in the kiwifruit group (P = 0.016). Urinary excretion was calculated as ~40% and ~50% of the ingested dose from the vitamin C tablet and kiwifruit arms, respectively. Overall, our pharmacokinetic study has shown comparable relative bioavailability of kiwifruit-derived vitamin C and synthetic vitamin C.

Uric acid, an important screening tool to detect inborn errors of metabolism: a case series.

PubMed

Jasinge, Eresha; Kularatnam, Grace Angeline Malarnangai; Dilanthi, Hewa Warawitage; Vidanapathirana, Dinesha Maduri; Jayasena, Kandana Liyanage Subhashinie Priyadarshika Kapilani Menike; Chandrasiri, Nambage Dona Priyani Dhammika; Indika, Neluwa Liyanage Ruwan; Ratnayake, Pyara Dilani; Gunasekara, Vindya Nandani; Fairbanks, Lynette Dianne; Stiburkova, Blanka

2017-09-06

Uric acid is the metabolic end product of purine metabolism in humans. Altered serum and urine uric acid level (both above and below the reference ranges) is an indispensable marker in detecting rare inborn errors of metabolism. We describe different case scenarios of 4 Sri Lankan patients related to abnormal uric acid levels in blood and urine. CASE 1: A one-and-half-year-old boy was investigated for haematuria and a calculus in the bladder. Xanthine crystals were seen in microscopic examination of urine sediment. Low uric acid concentrations in serum and low urinary fractional excretion of uric acid associated with high urinary excretion of xanthine and hypoxanthine were compatible with xanthine oxidase deficiency. CASE 2: An 8-month-old boy presented with intractable seizures, feeding difficulties, screaming episodes, microcephaly, facial dysmorphism and severe neuro developmental delay. Low uric acid level in serum, low fractional excretion of uric acid and radiological findings were consistent with possible molybdenum cofactor deficiency. Diagnosis was confirmed by elevated levels of xanthine, hypoxanthine and sulfocysteine levels in urine. CASE 3: A 3-year-10-month-old boy presented with global developmental delay, failure to thrive, dystonia and self-destructive behaviour. High uric acid levels in serum, increased fractional excretion of uric acid and absent hypoxanthine-guanine phosphoribosyltransferase enzyme level confirmed the diagnosis of Lesch-Nyhan syndrome. CASE 4: A 9-year-old boy was investigated for lower abdominal pain, gross haematuria and right renal calculus. Low uric acid level in serum and increased fractional excretion of uric acid pointed towards hereditary renal hypouricaemia which was confirmed by genetic studies. Abnormal uric acid level in blood and urine is a valuable tool in screening for clinical conditions related to derangement of the nucleic acid metabolic pathway.

Stem Cell Therapy in Bladder Dysfunction: Where Are We? And Where Do We Have to Go?

PubMed Central

Lee, Sang-Rae; Song, Yun Seob; Lee, Hong Jun

2013-01-01

To date, stem cell therapy for the bladder has been conducted mainly on an experimental basis in the areas of bladder dysfunction. The therapeutic efficacy of stem cells was originally thought to be derived from their ability to differentiate into various cell types. Studies about stem cell therapy for bladder dysfunction have been limited to an experimental basis and have been less focused than bladder regeneration. Bladder dysfunction was listed in MESH as “urinary bladder neck obstruction”, “urinary bladder, overactive”, and “urinary bladder, neurogenic”. Using those keywords, several articles were searched and studied. The bladder dysfunction model includes bladder outlet obstruction, cryoinjured, diabetes, ischemia, and spinal cord injury. Adipose derived stem cells (ADSCs), bone marrow stem cells (BMSCs), and skeletal muscle derived stem cells (SkMSCs) are used for transplantation to treat bladder dysfunction. The main mechanisms of stem cells to reconstitute or restore bladder dysfunction are migration, differentiation, and paracrine effects. The aim of this study is to review the stem cell therapy for bladder dysfunction and to provide the status of stem cell therapy for bladder dysfunction. PMID:24151627

Synthesis and antitumor activity of seleno- and thio-purines complexed with cis-diamminoplatinum (II).

PubMed

Maeda, M; Abiko, N; Sasaki, T

1982-02-01

cis-Diamminoplatinum (II) complexes with selenoguanine, thioguanine, 6-thioxanthine, or 6-mercaptopurine were synthesized by the reaction of stoichiometric amounts of selenopurine or thiopurine with aquated cis-dichlorodimmineplatinum (II) in slightly acidic medium, and their antitumor activity was studied against L1210 cells in mice. These compounds exhibited a medium antitumor activity with very low toxicity. The antitumor activity was dependent on the nature of the purine ligand. These complexes were very stable in various aqueous solvents at 37 degrees C for 10 d but not in the presence of mouse serum. The mechanism of the action effected by the complex is not clear. However, the slow release of an antitumor active purine from the complex, SeG-Pt (NH3)2, was observed.

Purification, crystallization, and preliminary X-ray diffraction study of purine nucleoside phosphorylase from E. coli

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abramchik, Yu. A., E-mail: inna@ns.crys.ras.ru; Timofeev, V. I., E-mail: espiov@ibch.ru; Zhukhlistova, N. E., E-mail: tostars@mail.ru

2015-07-15

Crystals of E. coli purine nucleoside phosphorylase were grown in microgravity by the capillary counter-diffusion method through a gel layer. The X-ray diffraction data set suitable for the determination of the three-dimensional structure at atomic resolution was collected from one crystal at the Spring-8 synchrotron facility to 0.99 Å resolution. The crystals belong to sp. gr. P2{sub 1} and have the following unit-cell parameters: a = 74.1 Å, b = 110.2 Å, c = 88.2 Å, α = γ = 90°, β = 111.08°. The crystal contains six subunits of the enzyme comprising a hexamer per asymmetric unit. The hexamermore » is the biological active form of E. coli. purine nucleoside phosphorylase.« less

Excited triplet state of N-(9-methylpurin-6-yl)pyridinium cation as an efficient photosensitizer in the oxidation of sulfur-containing amino acids. Laser flash and steady-state photolysis studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marciniak, B.; Hug, G.L.; Bobrowski, K.

1995-01-11

In this paper, we present and discuss the results of a detailed mechanistic study of the photosensitized oxidation of sulfur-containing amino acids by N-(9-methylpurin-6-yl)pyridinium cations in aqueous solution. The results provide data on the photoreactivity of the pyridinium salts (derived from the purine bases) in the presence of the electron donors such as sulfur-containing organic compounds and give new experimental evidence for the general mechanism of the sensitized photooxidation of thioethers proposed previously. 39 refs., 6 figs., 2 tabs.

Antimicrobial Potential of Benzimidazole Derived Molecules.

PubMed

Bansal, Yogita; Kaur, Manjinder; Bansal, Gulshan

2017-10-31

Structural resemblance of benzimidazole nucleus with purine nucleus in nucleotides makes benzimidazole derivatives attractive ligands to interact with biopolymers of a living system. The most prominent benzimidazole compound in nature is N-ribosyldimethylbenzimidazole, which serves as an axial ligand for cobalt in vitamin B12. This structural similarity prompted medicinal chemists across the globe to synthesize a variety of benzimidazole derivatives and to screen those for various biological activities, such as anticancer, hormone antagonist, antiviral, anti-HIV, anthelmintic, antiprotozoal, antimicrobial, antihypertensive, anti-inflammatory, analgesic, anxiolytic, antiallergic, coagulant, anticoagulant, antioxidant and antidiabetic activities. Hence, benzimidazole nucleus is considered as a privileged structure in drug discovery, and it is exploited by many research groups to develop numerous compounds that are purported to be antimicrobial. Despite a large volume of research in this area, no novel benzimidazole derived compound has emerged as clinically effective antimicrobial drug. In the present review, we have compiled various reports on benzimidazole derived antimicrobials, classified as monosubstituted, disubstituted, trisubstituted and tetrasubstituted benzimidazoles, bis-benzimidazoles, fused-benzimidazoles, and benzimidazole derivative-metal complexes. The purpose is to collate these research reports, and to generate a generalised outlay of benzimidazole derived molecules that can assist the medicinal chemists in selecting appropriate combination of substituents around the nucleus for designing potent antimicrobials. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Structural and catalytic effects of an invariant purine substitution in the hammerhead ribozyme: implications for the mechanism of acid–base catalysis

PubMed Central

Schultz, Eric P.; Vasquez, Ernesto E.; Scott, William G.

2014-01-01

The hammerhead ribozyme catalyzes RNA cleavage via acid–base catalysis. Whether it does so by general acid–base catalysis, in which the RNA itself donates and abstracts protons in the transition state, as is typically assumed, or by specific acid–base catalysis, in which the RNA plays a structural role and proton transfer is mediated by active-site water molecules, is unknown. Previous biochemical and crystallographic experiments implicate an invariant purine in the active site, G12, as the general base. However, G12 may play a structural role consistent with specific base catalysis. To better understand the role of G12 in the mechanism of hammerhead catalysis, a 2.2 Å resolution crystal structure of a hammerhead ribozyme from Schistosoma mansoni with a purine substituted for G12 in the active site of the ribozyme was obtained. Comparison of this structure (PDB entry 3zd4), in which A12 is substituted for G, with three previously determined structures that now serve as important experimental controls, allows the identification of structural perturbations that are owing to the purine substitution itself. Kinetic measurements for G12 purine-substituted schistosomal hammerheads confirm a previously observed dependence of rate on the pK a of the substituted purine; in both cases inosine, which is similar to G in pK a and hydrogen-bonding properties, is unexpectedly inactive. Structural comparisons indicate that this may primarily be owing to the lack of the exocyclic 2-amino group in the G12A and G12I substitutions and its structural effect upon both the nucleotide base and phosphate of A9. The latter involves the perturbation of a previously identified and well characterized metal ion-binding site known to be catalytically important in both minimal and full-length hammerhead ribozyme sequences. The results permit it to be suggested that G12 plays an important role in stabilizing the active-site structure. This result, although not inconsistent with the potential role of G12 as a general base, indicates that an alternative hammerhead cleavage mechanism involving specific base catalysis may instead explain the observed rate dependence upon purine substitutions at G12. The crystallographic results, contrary to previous assumptions, therefore cannot be interpreted to favor the general base catalysis mecahnism over the specific base catalysis mechanism. Instead, both of these mutually exclusive mechanistic alternatives must be considered in light of the current structural and biochemical data. PMID:25195740

Structural and catalytic effects of an invariant purine substitution in the hammerhead ribozyme: implications for the mechanism of acid-base catalysis.

PubMed

Schultz, Eric P; Vasquez, Ernesto E; Scott, William G

2014-09-01

The hammerhead ribozyme catalyzes RNA cleavage via acid-base catalysis. Whether it does so by general acid-base catalysis, in which the RNA itself donates and abstracts protons in the transition state, as is typically assumed, or by specific acid-base catalysis, in which the RNA plays a structural role and proton transfer is mediated by active-site water molecules, is unknown. Previous biochemical and crystallographic experiments implicate an invariant purine in the active site, G12, as the general base. However, G12 may play a structural role consistent with specific base catalysis. To better understand the role of G12 in the mechanism of hammerhead catalysis, a 2.2 Å resolution crystal structure of a hammerhead ribozyme from Schistosoma mansoni with a purine substituted for G12 in the active site of the ribozyme was obtained. Comparison of this structure (PDB entry 3zd4), in which A12 is substituted for G, with three previously determined structures that now serve as important experimental controls, allows the identification of structural perturbations that are owing to the purine substitution itself. Kinetic measurements for G12 purine-substituted schistosomal hammerheads confirm a previously observed dependence of rate on the pK(a) of the substituted purine; in both cases inosine, which is similar to G in pK(a) and hydrogen-bonding properties, is unexpectedly inactive. Structural comparisons indicate that this may primarily be owing to the lack of the exocyclic 2-amino group in the G12A and G12I substitutions and its structural effect upon both the nucleotide base and phosphate of A9. The latter involves the perturbation of a previously identified and well characterized metal ion-binding site known to be catalytically important in both minimal and full-length hammerhead ribozyme sequences. The results permit it to be suggested that G12 plays an important role in stabilizing the active-site structure. This result, although not inconsistent with the potential role of G12 as a general base, indicates that an alternative hammerhead cleavage mechanism involving specific base catalysis may instead explain the observed rate dependence upon purine substitutions at G12. The crystallographic results, contrary to previous assumptions, therefore cannot be interpreted to favor the general base catalysis mecahnism over the specific base catalysis mechanism. Instead, both of these mutually exclusive mechanistic alternatives must be considered in light of the current structural and biochemical data.

Body Mass Changes Associated With Hyper-Gravity are Independent of Adrenal Derived Hormones

NASA Technical Reports Server (NTRS)

Wade, Charles E.; Moran, Megan M.; Wang, Tommy J.; Baer, Lisa A.; Yuan, Fang; Fung, Cyra K.; Stein, T. Peter; Dalton, Bonnie P. (Technical Monitor)

2001-01-01

Exposure to hyper-gravity results in a number of metabolic changes associated with increases in catecholamines and corticosterone. These changes result in a loss of body and fat mass. To assess the role of hormones derived from the adrenal gland in the changes we studied sham operated (SO) and adrenalectomized (ADX) male rats exposed to hyper-gravity of 2 G for 14 days. Control groups at 1 G were also studied. Urinary epinephrine (EPI) and corticosterone (CORT) were reduced in ADX animals. In response to 2 G there was an increase in urinary EPI and CORT in SO rats, while levels were unchanged in ADX animals. Both groups of animals had similar increases in urinary norepinephrine levels. The reductions of body mass gain in response to 2 G were the same in both groups. The decrease in relative fat mass was greater in ADX. Energy intake and expenditure were not different between groups. In response of returning to 1 G for 24 hours and reexposure to hyper-gravity there were no differences between SO and ADX in the changes of food and water intake, body mass or activity. The changes in metabolism with exposure to hyper-gravity do not appear to require hormones derived from the adrenal gland. The increase in lypolysis and alterations body and fat mass appear to be modulated by sympathetically derived norepinehrine.

Wobble↔Watson-Crick tautomeric transitions in the homo-purine DNA mismatches: a key to the intimate mechanisms of the spontaneous transversions.

PubMed

Brovarets', Ol'ha O; Hovorun, Dmytro M

2015-01-01

The intrinsic capability of the homo-purine DNA base mispairs to perform wobble↔Watson-Crick/Topal-Fresco tautomeric transitions via the sequential intrapair double proton transfer was discovered for the first time using QM (MP2/DFT) and QTAIM methodologies that are crucial for understanding the microstructural mechanisms of the spontaneous transversions.

Bladder sensory physiology: neuroactive compounds and receptors, sensory transducers, and target-derived growth factors as targets to improve function

PubMed Central

Gonzalez, Eric J.; Merrill, Liana

2014-01-01

Urinary bladder dysfunction presents a major problem in the clinical management of patients suffering from pathological conditions and neurological injuries or disorders. Currently, the etiology underlying altered visceral sensations from the urinary bladder that accompany the chronic pain syndrome, bladder pain syndrome (BPS)/interstitial cystitis (IC), is not known. Bladder irritation and inflammation are histopathological features that may underlie BPS/IC that can change the properties of lower urinary tract sensory pathways (e.g., peripheral and central sensitization, neurochemical plasticity) and contribute to exaggerated responses of peripheral bladder sensory pathways. Among the potential mediators of peripheral nociceptor sensitization and urinary bladder dysfunction are neuroactive compounds (e.g., purinergic and neuropeptide and receptor pathways), sensory transducers (e.g., transient receptor potential channels) and target-derived growth factors (e.g., nerve growth factor). We review studies related to the organization of the afferent limb of the micturition reflex and discuss neuroplasticity in an animal model of urinary bladder inflammation to increase the understanding of functional bladder disorders and to identify potential novel targets for development of therapeutic interventions. Given the heterogeneity of BPS/IC and the lack of consistent treatment benefits, it is unlikely that a single treatment directed at a single target in micturition reflex pathways will have a mass benefit. Thus, the identification of multiple targets is a prudent approach, and use of cocktail treatments directed at multiple targets should be considered. PMID:24760999

Advances in stem cell therapy for the lower urinary tract.

PubMed

Lin, Ching-Shwun

2010-02-26

Lower urinary tract diseases are emotionally and financially burdensome to the individual and society. Current treatments are ineffective or symptomatic. Conversely, stem cells (SCs) are regenerative and may offer long-term solutions. Among the different types of SCs, bone marrow SCs (BMSCs) and skeletal muscle-derived SCs (SkMSCs) have received the most attention in pre-clinical and clinical trial studies concerning the lower urinary tract. In particular, clinical trials with SkMSCs for stress urinary incontinence have demonstrated impressive efficacy. However, both SkMSCs and BMSCs are difficult to obtain in quantity and therefore neither is optimal for the eventual implementation of SC therapy. On the other hand, adipose tissue-derived SCs (ADSCs) can be easily and abundantly obtained from "discarded" adipose tissue. Moreover, in several head-on comparison studies, ADSCs have demonstrated equal or superior therapeutic potential compared to BMSCs. Therefore, across several different medical disciplines, including urology, ADSC research is gaining wide attention. For the regeneration of bladder tissues, possible differentiation of ADSCs into bladder smooth muscle and epithelial cells has been demonstrated. For the treatment of bladder diseases, specifically hyperlipidemia and associated overactive bladder, ADSCs have also demonstrated efficacy. For the treatment of urethral sphincter dysfunction associated with birth trauma and hormonal deficiency, ADSC therapy was also beneficial. Finally, ADSCs were able to restore erectile function in various types of erectile dysfunction (ED), including those associated with diabetes, hyperlipidemia, and nerve injuries. Thus, ADSCs have demonstrated remarkable therapeutic potentials for the lower urinary tract.

Stacking of purines in water: the role of dipolar interactions in caffeine.

PubMed

Tavagnacco, L; Di Fonzo, S; D'Amico, F; Masciovecchio, C; Brady, J W; Cesàro, A

2016-05-11

During the last few decades it has been ascertained that base stacking is one of the major contributions stabilizing nucleic acid conformations. However, the understanding of the nature of the interactions involved in the stacking process remains under debate and it is a subject of theoretical and experimental studies. Structural similarity between purine bases (guanine and adenine) in DNA and the caffeine molecule makes caffeine an excellent model for the purine bases. The present study clearly shows that dipolar interactions play a fundamental role in determining stacking of purine molecules in solution. In order to reach this achievement, polarized ultraviolet Raman resonant scattering experiments have been carried out on caffeine aqueous solutions as a function of concentration and temperature. The investigation pointed out at the aggregation and solvation properties, particularly at elevated temperatures. Kubo-Anderson theory was used as a framework to investigate the non-coincidence effect (NCE) occurring in the totally symmetric breathing modes of the purine rings, and in the bending modes of the methyl groups of caffeine. The NCE concentration dependence shows that caffeine aggregation at 80 °C occurs by planar stacking of the hydrophobic faces. The data clearly indicate that dipolar interactions determine the reorientational motion of the molecules in solution and are the driving force for the stacking of caffeine. In parallel, the observed dephasing times imply a change in caffeine interactions as a function of temperature and concentration. A decrease, at low water content, of the dephasing time for the ring breathing vibration mode indicates that self-association alters the solvation structure that is detectable at low concentration. These results are in agreement with simulation predictions and serve as an important validation of the models used in those calculations.

Theoretical and experimental studies on the corrosion inhibition potentials of some purines for aluminum in 0.1 M HCl

PubMed Central

Eddy, Nnabuk O.; Momoh-Yahaya, H.; Oguzie, Emeka E.

2014-01-01

Experimental aspect of the corrosion inhibition potential of adenine (AD), guanine (GU) and, hypoxanthine (HYP) was carried out using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods while the theoretical aspect of the work was carried out by calculations of semi-empirical parameters (for AM1, MNDO, CNDO, PM3 and RM1 Hamiltonians), Fukui functions and inhibitor–metal interaction energies. Results obtained from the experimental studies were in good agreement and indicated that adenine (AD), guanine (GU) and hypoxanthine (HYP) are good adsorption inhibitors for the corrosion of aluminum in solutions of HCl. Data obtained from electrochemical experiment revealed that the studied purines functioned by adsorption on the aluminum/HCl interface and inhibited the cathodic half reaction to a greater extent and anodic half reaction to a lesser extent. The adsorption of the purines on the metal surface was found to be exothermic and spontaneous. Deviation of the adsorption characteristics of the studied purines from the Langmuir adsorption model was compensated by the fitness of Flory Huggins and El Awardy et al. adsorption models. Quantum chemical studies revealed that the experimental inhibition efficiencies of the studied purines are functions of some quantum chemical parameters including total energy of the molecules (TE), energy gap (EL–H), electronic energy of the molecule (EE), dipole moment and core–core repulsion energy (CCR). Fukui functions analysis through DFT and MP2 theories indicated slight complications and unphysical results. However, results obtained from calculated Huckel charges, molecular orbital and interaction energies, the adsorption of the inhibitors proceeded through the imine nitrogen (N5) in GU, emanine nitrogen (N7) in AD and the pyridine nitrogen (N5) in HPY. PMID:25750754

Theoretical and experimental studies on the corrosion inhibition potentials of some purines for aluminum in 0.1 M HCl.

PubMed

Eddy, Nnabuk O; Momoh-Yahaya, H; Oguzie, Emeka E

2015-03-01

Experimental aspect of the corrosion inhibition potential of adenine (AD), guanine (GU) and, hypoxanthine (HYP) was carried out using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods while the theoretical aspect of the work was carried out by calculations of semi-empirical parameters (for AM1, MNDO, CNDO, PM3 and RM1 Hamiltonians), Fukui functions and inhibitor-metal interaction energies. Results obtained from the experimental studies were in good agreement and indicated that adenine (AD), guanine (GU) and hypoxanthine (HYP) are good adsorption inhibitors for the corrosion of aluminum in solutions of HCl. Data obtained from electrochemical experiment revealed that the studied purines functioned by adsorption on the aluminum/HCl interface and inhibited the cathodic half reaction to a greater extent and anodic half reaction to a lesser extent. The adsorption of the purines on the metal surface was found to be exothermic and spontaneous. Deviation of the adsorption characteristics of the studied purines from the Langmuir adsorption model was compensated by the fitness of Flory Huggins and El Awardy et al. adsorption models. Quantum chemical studies revealed that the experimental inhibition efficiencies of the studied purines are functions of some quantum chemical parameters including total energy of the molecules (TE), energy gap (E L-H), electronic energy of the molecule (EE), dipole moment and core-core repulsion energy (CCR). Fukui functions analysis through DFT and MP2 theories indicated slight complications and unphysical results. However, results obtained from calculated Huckel charges, molecular orbital and interaction energies, the adsorption of the inhibitors proceeded through the imine nitrogen (N5) in GU, emanine nitrogen (N7) in AD and the pyridine nitrogen (N5) in HPY.

Cytotoxicity and Antineoplastic Activities of Alkylamines and Their Borane Derivatives

PubMed Central

Tse, Elaine Y.; Muhammad, Rosallah A.

1996-01-01

The alkylamines and their related boron derivatives demonstrated potent cytotoxicity against the growth of murine and human tissue cultured cells. These agents did not necessarily require the boron atom to possess potent cytotoxic action in certain tumor lines. Their ability to suppress tumor cell growth was based on their inhibition of DNA and protein syntheses. DNA synthesis was reduced because purine synthesis was blocked at the enzyme site of IMP dehydrogenase by the agents. In addition ribonucleotide reductase and nucleoside kinase activities were reduced by the agents which would account for the reduced d[NTP] pools. The DNA template or molecule may be a target of the drugs with regard to binding of the drug to nucleoside bases or intercalaction of the drug between DNA base pairs. Only some Of the agents caused DNA fragmentation with reduced DNA viscosity. These effects would contribute to overall cell death afforded by the agents. PMID:18472803

Synthesis of some purine and pyrimidine nucleosides of 3-amino-2,3,6-trideoxy-L-lyxo-hexopyranose (daunosamine).

PubMed

Lazzari, E; Vigevani, A; Arcamone, F

1977-06-01

The daunosaminyl analogue of the antibiotic puromycin and the nucleoside derivatives of daunosamine with adenine, thymine, and cytosine have been synthesised. The nucleoside derivatives of 6-dimethylaminopurine, thymine, and cytosine were prepared by melting the protected daunosamine with the protected base in vacuo. Daunosaminyladenine was obtained by condensing N-trifluoroacetyl-O-trifluoroacetyl-alpha-daunosaminyl chloride either with N6-benzoyl-9-chloromercuryadenine in boiling xylene or with N6-benzoyladenine in dichloromethane at room temperature in the presence of a molecular sieve. In each reaction, the beta-anomeric nucleoside was obtained, as shown by p.m.r. data. The protecting groups were removed with barium hydroxide or methanolic ammonia to give the free aminonucleosides in good yield. 9-beta-Daunosaminyl-6-dimethylaminopurine was coupled to N-benzylocyxcarbonyl-O-methyltyrosine, giving, after hydrogenolysis, the daunosaminyl analogue of puromycin.

Prevalence of symptomatic urinary calculi in Kerman, Iran.

PubMed

Ketabchi, Ali Asghar; Aziziolahi, Gholam Abbas

2008-01-01

In a cross-sectional study, we evaluated the prevalence of symptomatic urinary calculi in Kerman, Iran. A total of 2431 citizens of Kerman were surveyed from September of 2005 to April 2006. The study population was selected by cluster method from 5 different areas, and 100 houses in each area were randomly approached. Questions on the urinary symptoms consisted of flank pain, urogenital pain, dysuria or any difficulty in urination, and alterations in urine color. Individuals with a suspicion of urinary calculi based on their symptoms were evaluated by physical examination, laboratory investigations, and plain abdominal radiography. Ultrasonography and intravenous urography were done if required to confirm the diagnoses. Of 2431 individuals, 196 (8.1%) had symptoms in favor of urinary calculus diagnosis, of whom 47 (24.0%) had urinary calculi (prevalence of symptomatic urolithiasis was 1.9%). Of the patients, 35 (74.5%) were underweight. Compared to the other participants, the patients with urinary calculus were younger (P = .001) and a larger proportion of them had a positive family history of urinary calculi (14.9% versus 6.5%; P = .02) and were rug weavers and office employees. Dependency on opium and its derivative was significantly more frequent in patients with urinary calculi (25.5% versus 0.2%; P = .001). This study showed that the prevalence of symptomatic urinary calculi in this hot and dry area is relatively high. According to our findings, the other factors including specific occupations, malnutrition, and substance use may also have influence on the rate of urinary calculus formation. Therefore, to prevention and early treatment of urinary calculi, evaluation of potential predisposing conditions should be considered with special attention to regional factors.

Direct Isolation of Purines and Pyrimidines from Nucleic Acids Using Sublimation

NASA Technical Reports Server (NTRS)

Glavin, Daniel P.; Schubert, Michael; Bada, Jeffrey L.

2003-01-01

A sublimation technique was developed to isolate purines and pyrimidines directly from lambda-deoxyribonucleic acid (lambda-DNA) and Escherichia coli cells. The sublimation of adenine, cytosine, guanine, and thymine from lambda-DNA was tested under reduced pressure (approx. 0.5 Torr) at temperatures of >150 C. With the exception of guanine, approximately 60 -75% of each base was sublimed directly from the lambda-DNA and recovered on a coldfinger of the sublimation apparatus after heating to 450 C. Several nucleobases including adenine, cytosine, thymine, and uracil were also recovered from E. coli bacteria after heating the cells to the same temperature, although some thermal decomposition of the bases also occurred. These results demonstrate the feasibility of using sublimation to isolate purines and pyrimidines from native E. coli DNA and RNA without any chemical treatment of the cells.

Amino acid derivatives of 5-ASA as novel prodrugs for intestinal drug delivery.

PubMed

Clerici, C; Gentili, G; Boschetti, E; Santucci, C; Aburbeh, A G; Natalini, B; Pellicciari, R; Morelli, A

1994-12-01

In an attempt to obtain site-specific delivery of 5-ASA in the intestinal tract, we have determined the extent of absorption and metabolism of a number of novel 5-ASA derivatives, namely, (N-L-glutamyl)-amino-2-salicylic acid (1), (N-L-aspartyl)-amino-2-salicylic-acid (2), 5-aminosalicyl-L-proline-L-leucine (3), and 5-(N-L-glutamyl)-aminosalicyl-L-proline-L-leucine (4), which are selectively cleaved by intestinal brush border aminopeptidase A and carboxypeptidases. These novel prodrugs, 5-ASA, and sulfasalazine were administered to adult Fisher rats (N = 30) and to animals that had undergone prior colostomy (N = 30). Urine and feces were collected at timed intervals for 48 hr and the metabolites, 5-ASA, and N-acetyl-5-ASA were measured by high-performance liquid chromatography. The absorption and metabolism of all compounds were essentially identical in colostomized and normal animals. 5-ASA exhibited a rapid proximal intestinal absorption as evidenced by the high cumulative urinary excretion (> 65%) and low fecal excretion. Sulfasalazine, as expected, exhibited a lower urinary recovery (< 35%) and higher fecal excretion of 5-ASA and its metabolite. The novel glutamate and aspartate derivatives (1 and 2) behaved similarly to sulfasalazine, while administration of the proline-leucine derivative (3) resulted in urinary and fecal recovery values intermediate with respect to those observed with 5-ASA and sulfasalazine. 5-(N-L-Glutamyl)-aminosalicyl-L-proline-L-leucine yielded the highest fecal recovery of 5-ASA and its N-acetyl derivative, indicating a more efficient delivery to the distal bowel. Amino acid derivatives of 5-ASA appear to be potentially useful prodrugs for the site-specific delivery of 5-ASA to different regions of the intestinal tract.

Physiology and pathophysiology of the vasopressin-regulated renal water reabsorption

PubMed Central

Boone, Michelle

2008-01-01

To prevent dehydration, terrestrial animals and humans have developed a sensitive and versatile system to maintain their water homeostasis. In states of hypernatremia or hypovolemia, the antidiuretic hormone vasopressin (AVP) is released from the pituitary and binds its type-2 receptor in renal principal cells. This triggers an intracellular cAMP signaling cascade, which phosphorylates aquaporin-2 (AQP2) and targets the channel to the apical plasma membrane. Driven by an osmotic gradient, pro-urinary water then passes the membrane through AQP2 and leaves the cell on the basolateral side via AQP3 and AQP4 water channels. When water homeostasis is restored, AVP levels decline, and AQP2 is internalized from the plasma membrane, leaving the plasma membrane watertight again. The action of AVP is counterbalanced by several hormones like prostaglandin E2, bradykinin, dopamine, endothelin-1, acetylcholine, epidermal growth factor, and purines. Moreover, AQP2 is strongly involved in the pathophysiology of disorders characterized by renal concentrating defects, as well as conditions associated with severe water retention. This review focuses on our recent increase in understanding of the molecular mechanisms underlying AVP-regulated renal water transport in both health and disease. PMID:18431594

Dietary treatment of urinary risk factors for renal stone formation. A review of CLU Working Group.

PubMed

Prezioso, Domenico; Strazzullo, Pasquale; Lotti, Tullio; Bianchi, Giampaolo; Borghi, Loris; Caione, Paolo; Carini, Marco; Caudarella, Renata; Ferraro, Manuel; Gambaro, Giovanni; Gelosa, Marco; Guttilla, Andrea; Illiano, Ester; Martino, Marangella; Meschi, Tiziana; Messa, Piergiorgio; Miano, Roberto; Napodano, Giorgio; Nouvenne, Antonio; Rendina, Domenico; Rocco, Francesco; Rosa, Marco; Sanseverino, Roberto; Salerno, Annamaria; Spatafora, Sebastiano; Tasca, Andrea; Ticinesi, Andrea; Travaglini, Fabrizio; Trinchieri, Alberto; Vespasiani, Giuseppe; Zattoni, Filiberto

2015-07-07

Diet interventions may reduce the risk of urinary stone formation and its recurrence, but there is no conclusive consensus in the literature regarding the effectiveness of dietary interventions and recommendations about specific diets for patients with urinary calculi. The aim of this study was to review the studies reporting the effects of different dietary interventions for the modification of urinary risk factors in patients with urinary stone disease. A systematic search of the Pubmed database literature up to July 1, 2014 for studies on dietary treatment of urinary risk factors for urinary stone formation was conducted according to a methodology developed a priori. Studies were screened by titles and abstracts for eligibility. Data were extracted using a standardized form and the quality of evidence was assessed. Evidence from the selected studies were used to form evidence-based guideline statements. In the absence of sufficient evidence, additional statements were developed as expert opinions. General measures: Each patient with nephrolithiasis should undertake appropriate evaluation according to the knowledge of the calculus composition. Regardless of the underlying cause of the stone disease, a mainstay of conservative management is the forced increase in fluid intake to achieve a daily urine output of 2 liters. HYPERCALCIURIA: Dietary calcium restriction is not recommended for stone formers with nephrolithiasis. Diets with a calcium content ≥ 1 g/day (and low protein-low sodium) could be protective against the risk of stone formation in hypercalciuric stone forming adults. Moderate dietary salt restriction is useful in limiting urinary calcium excretion and thus may be helpful for primary and secondary prevention of nephrolithiasis. A low-normal protein intake decrease calciuria and could be useful in stone prevention and preservation of bone mass. Omega-3 fatty acids and bran of different origin decreases calciuria, but their impact on the urinary stone risk profile is uncertain. Sports beverage do not affect the urinary stone risk profile. HYPEROXALURIA: A diet low in oxalate and/or a calcium intake normal to high (800-1200 mg/day for adults) reduce the urinary excretion of oxalate, conversely a diet rich in oxalates and/or a diet low in calcium increase urinary oxalate. A restriction in protein intake may reduce the urinary excretion of oxalate although a vegetarian diet may lead to an increase in urinary oxalate. Adding bran to a diet low in oxalate cancels its effect of reducing urinary oxalate. Conversely, the addition of supplements of fruit and vegetables to a mixed diet does not involve an increased excretion of oxalate in the urine. The intake of pyridoxine reduces the excretion of oxalate. HYPERURICOSURIA: In patients with renal calcium stones the decrease of the urinary excretion of uric acid after restriction of dietary protein and purine is suggested although not clearly demonstrated. HYPOCITRATURIA: The administration of alkaline-citrates salts is recommended for the medical treatment of renal stone-formers with hypocitraturia, although compliance to this treatment is limited by gastrointestinal side effects and costs. Increased intake of fruit and vegetables (excluding those with high oxalate content) increases citrate excretion and involves a significant protection against the risk of stone formation. Citrus (lemons, oranges, grapefruit, and lime) and non citrus fruits (melon) are natural sources of dietary citrate, and several studies have shown the potential of these fruits and/or their juices in raising urine citrate levels. There are enought basis to advice an adequate fluid intake also in children. Moderate dietary salt restriction and implementation of potassium intake are useful in limiting urinary calcium excretion whereas dietary calcium restriction is not recommended for children with nephrolithiasis. It seems reasonable to advice a balanced consumption of fruit and vegetables and a low consumption of chocolate and cola according to general nutritional guidelines, although no studies have assessed in pediatric stone formers the effect of fruit and vegetables supplementation on urinary citrate and the effects of chocolate and cola restriction on urinary oxalate in pediatric stone formers. Despite the low level of scientific evidence, a low-protein (< 20 g/day) low-salt (< 2 g/day) diet with high hydration (> 3 liters/day) is strongly advised in children with cystinuria. ELDERLY: In older patients dietary counseling for renal stone prevention has to consider some particular aspects of aging. A restriction of sodium intake in association with a higher intake of potassium, magnesium and citrate is advisable in order to reduce urinary risk factors for stone formation but also to prevent the loss of bone mass and the incidence of hypertension, although more hemodynamic sensitivity to sodium intake and decreased renal function of the elderly have to be considered. A diet rich in calcium (1200 mg/day) is useful to maintain skeletal wellness and to prevent kidney stones although an higher supplementation could involve an increase of risk for both the formation of kidney stones and cardiovascular diseases. A lower content of animal protein in association to an higher intake of plant products decrease the acid load and the excretion of uric acid has no particular contraindications in the elderly patients, although overall nutritional status has to be preserved.

Reprogramming One-Carbon Metabolic Pathways To Decouple l-Serine Catabolism from Cell Growth in Corynebacterium glutamicum.

PubMed

Zhang, Yun; Shang, Xiuling; Lai, Shujuan; Zhang, Yu; Hu, Qitiao; Chai, Xin; Wang, Bo; Liu, Shuwen; Wen, Tingyi

2018-02-16

l-Serine, the principal one-carbon source for DNA biosynthesis, is difficult for microorganisms to accumulate due to the coupling of l-serine catabolism and microbial growth. Here, we reprogrammed the one-carbon unit metabolic pathways in Corynebacterium glutamicum to decouple l-serine catabolism from cell growth. In silico model-based simulation showed a negative influence on glyA-encoding serine hydroxymethyltransferase flux with l-serine productivity. Attenuation of glyA transcription resulted in increased l-serine accumulation, and a decrease in purine pools, poor growth and longer cell shapes. The gcvTHP-encoded glycine cleavage (Gcv) system from Escherichia coli was introduced into C. glutamicum, allowing glycine-derived 13 CH 2 to be assimilated into intracellular purine synthesis, which resulted in an increased amount of one-carbon units. Gcv introduction not only restored cell viability and morphology but also increased l-serine accumulation. Moreover, comparative proteomic analysis indicated that abundance changes of the enzymes involved in one-carbon unit cycles might be responsible for maintaining one-carbon unit homeostasis. Reprogramming of the one-carbon metabolic pathways allowed cells to reach a comparable growth rate to accumulate 13.21 g/L l-serine by fed-batch fermentation in minimal medium. This novel strategy provides new insights into the regulation of cellular properties and essential metabolite accumulation by introducing an extrinsic pathway.

Rapid repair of UVA-induced oxidized purines and persistence of UVB-induced dipyrimidine lesions determine the mutagenicity of sunlight in mouse cells

PubMed Central

Besaratinia, Ahmad; Kim, Sang-in; Pfeifer, Gerd P.

2009-01-01

Despite the predominance of UVA relative to UVB in terrestrial sunlight, solar mutagenesis in humans and rodents is characterized by mutations specific for UVB. We have investigated the kinetics of repair of UVA- and UVB-induced DNA lesions in relation to mutagenicity in transgenic mouse fibroblasts irradiated with equilethal doses of UVA and UVB in comparison to SSL. We have also analyzed mutagenesis-derived carcinogenesis in sunlight-associated human skin cancers by compiling the published data on mutation types found in crucial genes in non-melanoma and melanoma skin cancers. Here, we demonstrate a resistance to repair of UVB-induced CPDs together with rapid removal of UVA-induced oxidized purines in the genome overall and in the cII transgene of SSL-irradiated cells. The spectra of mutation induced by both UVB- and SSL-irradiation in this experimental system are characterized by significant increases in relative frequency of C to T transitions at dipyrimidines, which are the established signature mutation of CPDs. This type of mutation is also the predominant mutation found in human non-melanoma and melanoma tumor samples in the TP53, CDKN2, PTCH, and protein kinase genes. The prevailing role of UVB over UVA in solar mutagenesis in our test system can be ascribed to different kinetics of repair for lesions induced by the respective UV-irradiation. PMID:18326785

Characterization of a purine permease family gene OsPUP7 involved in growth and development control in rice.

PubMed

Qi, Zhuyun; Xiong, Lizhong

2013-11-01

In this study, PUP-type cytokinin transporter genes were identified in rice (Oryza sativa L.). The Oryza sativa purine permease (OsPUP) family has 12 members that show similar predicted protein sequences with AtPUPs. To reveal the functions of OsPUP genes, we searched the T-DNA mutant library of rice and found one mutant for the member OsPUP7. The T-DNA insertion caused a new transcript that encodes a protein with 26 amino acids different from the native OsPUP7 at the C-terminus. The mutant showed multiple phenotypic changes including increased plant height, big seeds, and delayed flowering. The mutant also showed increased sensitivity to drought and salt stresses and treatments with kinetin and abscisic acid. OsPUP7 is expressed mainly in the vascular bundle, pistil, and stamens. The measurement of cytokinins (CKs) showed that CK content in the mutant spikelets accumulated higher than that in the wild type. Moreover, uptake experiment in the yeast fcy2 mutant suggested that OsPUP7 has the ability to transport caffeine, a CK derivative. Our results indicate that the PUP transport system also exists in rice, and OsPUP7 has an important role in the transport of CK, thus affecting developmental process and stress responses. © 2013 Institute of Botany, Chinese Academy of Sciences.

DNA mutation motifs in the genes associated with inherited diseases.

PubMed

Růžička, Michal; Kulhánek, Petr; Radová, Lenka; Čechová, Andrea; Špačková, Naďa; Fajkusová, Lenka; Réblová, Kamila

2017-01-01

Mutations in human genes can be responsible for inherited genetic disorders and cancer. Mutations can arise due to environmental factors or spontaneously. It has been shown that certain DNA sequences are more prone to mutate. These sites are termed hotspots and exhibit a higher mutation frequency than expected by chance. In contrast, DNA sequences with lower mutation frequencies than expected by chance are termed coldspots. Mutation hotspots are usually derived from a mutation spectrum, which reflects particular population where an effect of a common ancestor plays a role. To detect coldspots/hotspots unaffected by population bias, we analysed the presence of germline mutations obtained from HGMD database in the 5-nucleotide segments repeatedly occurring in genes associated with common inherited disorders, in particular, the PAH, LDLR, CFTR, F8, and F9 genes. Statistically significant sequences (mutational motifs) rarely associated with mutations (coldspots) and frequently associated with mutations (hotspots) exhibited characteristic sequence patterns, e.g. coldspots contained purine tract while hotspots showed alternating purine-pyrimidine bases, often with the presence of CpG dinucleotide. Using molecular dynamics simulations and free energy calculations, we analysed the global bending properties of two selected coldspots and two hotspots with a G/T mismatch. We observed that the coldspots were inherently more flexible than the hotspots. We assume that this property might be critical for effective mismatch repair as DNA with a mutation recognized by MutSα protein is noticeably bent.

Identification of a novel phosphatase with high affinity for nucleotides monophosphate from common bean (Phaseolus vulgaris).

PubMed

Cabello-Díaz, Juan Miguel; Quiles, Francisco Antonio; Lambert, Rocío; Pineda, Manuel; Piedras, Pedro

2012-04-01

Common bean (Phaseolus vulgaris) seedlings accumulate ureides derived from purines after germination. The first step in the conversion of purines to ureides is the removal of the 5'-phosphate group by a phosphatase that has not been established yet. Two main phosphatase activities were detected in the embryonic axes of common bean using inosine monophosphate as substrate in an in-gel assay. Both activities differed in their sensitive to the common phosphatase inhibitor molybdate, with the molybdate-resistant as the first enzyme induced after radicle protrusion. The molybdate-resistant phosphatase has been purified to electrophoretic homogeneity and this is the first enzyme which shows this resistance purified and characterized from plant tissues. The native enzyme was a monomer of 55 kDa and it showed highest activity with nucleotides as substrates, with the K(m) values in the micromolar range. Among nucleotides, the highest specific constant (V(max)/K(m)) was observed for adenosine monophosphate. Furthermore, the enzyme was inhibited by nucleosides, the products of the enzymatic reaction, with maximum effect for adenosine. Common bean seedlings imbibed in the presence of adenosine monophosphate in vivo showed the highest molybdate-resistant phosphatase activity in the axes in addition to increased ureide content. The data presented suggests that purified phosphatase is involved in nucleotide metabolism in embryonic axes from common bean. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Biochemistry of Trypanosomatidae of Importance in Africa.

DTIC Science & Technology

1982-12-01

product . Compounds which appear as likely candidates include the following: Formycin B Formycin-B-ronophosphate Formycin-A-monophosphate Formycin-A...tetrahydro-2-fur-yl) -purine N6-Dimenthyladenine 2 ,6-bis- Chydroxyamino) -9-B-D-ri-bofuranosy3.- purine 6- Mercaptopurine 6-iodo-9- (tetr-ahydro-2...controlled anti- parasitic vaccines. Membrane antigens differ from one species to another and during the course of infection, making the production of a usqful

Evidence for the binding of the carcinogen 3-methylcholanthrene to both the purine and the pyrimidine bases of hamster fibroblast deoxyribonucleic acid (Short Communication)

PubMed Central

Jones, Peter A.; Gevers, Wieland; Hawtrey, Arthur O.

1973-01-01

The binding of [3H]3-methylcholanthrene to the DNA of hamster fibroblasts was studied by using chemical methods for DNA degradation. DNA depurinated by mild acid hydrolysis released approximately half of the radioactivity at the same rate as the purine bases, but the resulting apurinic acid still contained radioactive carcinogen. PMID:4797167

Current Concepts of Hyperuricemia and Gout

PubMed Central

Klinenberg, James R.

1969-01-01

Recent studies have confirmed that gout is an inborn error of metabolism. It has now become evident that the hyperuricemia associated with gout might occur either due to overproduction of uric acid, underexcretion of uric acid or a combination of these processes. Furthermore, patients with excessive purine synthesis may have a specific enzyme defect resulting in altered feedback inhibition of purine synthesis. A neurological disease manifest by mental retardation, choreo-athetosis, aggressive behavior, lip-biting and self-mutilation and associated with decidedly increased purine biosynthesis serves as a prototype of this kind of disorder. Other defects in regulation of purine biosynthesis have been postulated but their existence not yet confirmed. It has been demonstrated that urate crystals which are deposited from hyperuricemic body fluids set up an acute inflammatory reaction by means of a variety of chemical mediators. Thus, acute gouty arthritis is now recognized as an example of “crystal induced” synovitis. The treatment of gout consists of (1) the control of acute gouty attacks, and (2) the maintenance of normal serum uric acid concentrations. This latter may be achieved either with uricosuric drugs or with xanthine oxidase inhibition. With these principles in mind, it is now possible to avoid many of the severe crippling effects of gout and to restore the vast majority of gouty patients to useful and productive lives. PMID:5773483

Nicotinamide riboside and nicotinic acid riboside salvage in fungi and mammals. Quantitative basis for Urh1 and purine nucleoside phosphorylase function in NAD+ metabolism.

PubMed

Belenky, Peter; Christensen, Kathryn C; Gazzaniga, Francesca; Pletnev, Alexandre A; Brenner, Charles

2009-01-02

NAD+ is a co-enzyme for hydride transfer enzymes and an essential substrate of ADP-ribose transfer enzymes and sirtuins, the type III protein lysine deacetylases related to yeast Sir2. Supplementation of yeast cells with nicotinamide riboside extends replicative lifespan and increases Sir2-dependent gene silencing by virtue of increasing net NAD+ synthesis. Nicotinamide riboside elevates NAD+ levels via the nicotinamide riboside kinase pathway and by a pathway initiated by splitting the nucleoside into a nicotinamide base followed by nicotinamide salvage. Genetic evidence has established that uridine hydrolase, purine nucleoside phosphorylase, and methylthioadenosine phosphorylase are required for Nrk-independent utilization of nicotinamide riboside in yeast. Here we show that mammalian purine nucleoside phosphorylase but not methylthioadenosine phosphorylase is responsible for mammalian nicotinamide riboside kinase-independent nicotinamide riboside utilization. We demonstrate that so-called uridine hydrolase is 100-fold more active as a nicotinamide riboside hydrolase than as a uridine hydrolase and that uridine hydrolase and mammalian purine nucleoside phosphorylase cleave nicotinic acid riboside, whereas the yeast phosphorylase has little activity on nicotinic acid riboside. Finally, we show that yeast nicotinic acid riboside utilization largely depends on uridine hydrolase and nicotinamide riboside kinase and that nicotinic acid riboside bioavailability is increased by ester modification.

Purines: forgotten mediators in traumatic brain injury.

PubMed

Jackson, Edwin K; Boison, Detlev; Schwarzschild, Michael A; Kochanek, Patrick M

2016-04-01

Recently, the topic of traumatic brain injury has gained attention in both the scientific community and lay press. Similarly, there have been exciting developments on multiple fronts in the area of neurochemistry specifically related to purine biology that are relevant to both neuroprotection and neurodegeneration. At the 2105 meeting of the National Neurotrauma Society, a session sponsored by the International Society for Neurochemistry featured three experts in the field of purine biology who discussed new developments that are germane to both the pathomechanisms of secondary injury and development of therapies for traumatic brain injury. This included presentations by Drs. Edwin Jackson on the novel 2',3'-cAMP pathway in neuroprotection, Detlev Boison on adenosine in post-traumatic seizures and epilepsy, and Michael Schwarzschild on the potential of urate to treat central nervous system injury. This mini review summarizes the important findings in these three areas and outlines future directions for the development of new purine-related therapies for traumatic brain injury and other forms of central nervous system injury. In this review, novel therapies based on three emerging areas of adenosine-related pathobiology in traumatic brain injury (TBI) were proposed, namely, therapies targeting 1) the 2',3'-cyclic adenosine monophosphate (cAMP) pathway, 2) adenosine deficiency after TBI, and 3) augmentation of urate after TBI. © 2016 International Society for Neurochemistry.

Effects of pyrimidines on the guinea-pig coronary vasculature.

PubMed Central

Vials, A. J.; Burnstock, G.

1993-01-01

1. The effects of the pyrimidines, uridine 5'-triphosphate (UTP), thymidine 5'-triphosphate (TTP) and cytidine 5'-triphosphate (CTP), were examined in the guinea-pig coronary bed, by use of a Langendorff technique. Comparisons were made with the actions of the purines adenosine 5'-triphosphate (ATP), inosine 5'-triphosphate (ITP) and guanosine 5'-triphosphate (GTP). The effect of, the nitric oxide synthase inhibitor, L-NG-nitroarginine methyl ester (L-NAME) and, the prostaglandin synthesis inhibitor, indomethacin on the vasodilator response to these purines and pyrimidines was examined. The effects of these inhibitors were assessed on their ability to inhibit both the amplitude and the area of the vasodilator response. 2. The relative order of potency of the purines and pyrimidines studied was ATP > UTP > ITP >> GTP, TTP, CTP. 3. The maximum amplitude and area of the vasodilator response to the pyrimidines, UTP (5 x 10(-10)-5 x 10(-7) mol), TTP (5 x 10(-8)-5 x 10(-7) mol) and CTP (5 x 10(-7) mol), and purines, ITP (5 x 10(-9)-5 x 10(-7) mol) and GTP (5 x 10(-8)-5 x 10(-7) mol), were significantly reduced by L-NAME (3 x 10(-5) and 10(-4) M).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8298797

DNA damage in lens epithelium of cataract patients in vivo and ex vivo.

PubMed

Øsnes-Ringen, Oyvind; Azqueta, Amaia O; Moe, Morten C; Zetterström, Charlotta; Røger, Magnus; Nicolaissen, Bjørn; Collins, Andrew R

2013-11-01

DNA damage has been described in the human cataractous lens epithelium, and oxidative stress generated by UV radiation and endogenous metabolic processes has been suggested to play a significant role in the pathogenesis of cataract. In this study, the aim was to explore the quality and relative quantity of DNA damage in lens epithelium of cataract patients in vivo and after incubation in a cell culture system. Capsulotomy specimens were analysed, before and after 1 week of ex vivo cultivation, using the comet assay to measure DNA strand breaks, oxidized purine and pyrimidine bases and UV-induced cyclobutane pyrimidine dimers. DNA strand breaks were barely detectable, oxidized pyrimidines and pyrimidine dimers were present at low levels, whereas there was a relatively high level of oxidized purines, which further increased after cultivation. The observed levels of oxidized purines in cataractous lens epithelium may support a theory consistent with light damage and oxidative stress as mediators of molecular damage to the human lens epithelium. Damage commonly associated with UV-B irradiation was relatively low. The levels of oxidized purines increased further in a commonly used culture system. This is of interest considering the importance and versatility of ex vivo systems in studies exploring the pathogenesis of cataract. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

Generation of a human induced pluripotent stem cell line from urinary cells of a healthy donor using integration free Sendai virus technology.

PubMed

Rossbach, Bella; Hildebrand, Laura; El-Ahmad, Linda; Stachelscheid, Harald; Reinke, Petra; Kurtz, Andreas

2017-05-01

We have generated a human induced pluripotent stem cell (iPSC) line derived from urinary cells of a 28year old healthy female donor. The cells were reprogrammed using a non-integrating viral vector and have shown full differentiation potential. Together with the iPSC line, the donor provided blood cells for the study of immunological effects of the iPSC line and its derivatives in autologous and allogeneic settings. The line is available and registered in the human pluripotent stem cell registry as BCRTi005-A. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Generation of a human induced pluripotent stem cell line from urinary cells of a healthy donor using an integration free vector.

PubMed

Rossbach, Bella; Hildebrand, Laura; El-Ahmad, Linda; Stachelscheid, Harald; Reinke, Petra; Kurtz, Andreas

2016-03-01

We have generated a human induced pluripotent stem cell (iPSC) line derived from urinary cells of a 30 year old healthy female donor. The cells were reprogrammed using a non-integrating viral vector and have shown full differentiation potential. Together with the iPSC-line, the donor provided blood cells for the study of immunological effects of the iPSC line and its derivatives in autologous and allogeneic settings. The line is available and registered in the human pluripotent stem cell registry as BCRTi004-A. Copyright © 2016 University of Texas at Austin Dell Medical School. Published by Elsevier B.V. All rights reserved.

The effects of infusions of ring-A-reduced derivatives of aldosterone on the antinatriuretic and kaliuretic actions of aldosterone.

PubMed

Morris, D J; Souness, G W; Saccoccio, N A; Harnik, M

1989-01-01

Infusion of Ring-A-reduced metabolites of aldosterone in adrenalectomized male rats for 4 days revealed that 5 alpha-Ring-A-reduced derivatives, 5 alpha-dihydroaldosterone (5 alpha-DHAldo; 2.5-5.0 micrograms/day), 3 alpha,5 alpha-tetrahydroaldosterone (3 alpha,5 alpha-THAldo; 5-25 micrograms/day), and 3 beta,5 alpha-THAldo (50-175 micrograms/day) possessed intrinsic Na+-retaining activity. The same infusions of 5 alpha-DHAldo, 3 alpha,5 alpha-THAldo, and 3 beta,5 alpha-THAldo, also lowered the urinary excretion of potassium. The 5 beta-Ring-A-reduced derivative 3 alpha,5 beta-THAldo did not demonstrate either of these biological properties. In another set of experiments, on the fourth day of infusion, aldosterone (0.1 microgram/rat) was administered acutely subcutaneously; none of the Ring-A-reduced derivatives altered the Na+-retaining activity of aldosterone. However, in a dose-dependent manner, both 3 alpha,5 alpha-THAldo and 3 beta,5 alpha-THAldo blunted the urinary K+-secretory effect of aldosterone; low dosages of 5 alpha-DHAldo and larger dosages of 3 alpha,5 beta-THAldo did not. Thus, the 5 alpha-reduced derivatives of aldosterone not only lowered urinary Na+ and K+ excretion in their own right, but two of them blunted the kaliuretic response of the parent mineralocorticoid, aldosterone. Further experiments will be required to determine whether these aldosterone metabolites are further metabolized or interconverted during the expression of the regulatory properties described here and whether these properties are physiologically relevant.

A Randomised Cross-Over Pharmacokinetic Bioavailability Study of Synthetic versus Kiwifruit-Derived Vitamin C

PubMed Central

Carr, Anitra C.; Bozonet, Stephanie M.; Vissers, Margreet C. M.

2013-01-01

Kiwifruit are a rich source of vitamin C and also contain numerous phytochemicals, such as flavonoids, which may influence the bioavailability of kiwifruit-derived vitamin C. The aim of this study was to compare the relative bioavailability of synthetic versus kiwifruit-derived vitamin C using a randomised cross-over pharmacokinetic study design. Nine non-smoking males (aged 18–35 years) received either a chewable tablet (200 mg vitamin C) or the equivalent dose from gold kiwifruit (Actinidia chinensis var. Sungold). Fasting blood and urine were collected half hourly to hourly over the eight hours following intervention. The ascorbate content of the plasma and urine was determined using HPLC with electrochemical detection. Plasma ascorbate levels increased from 0.5 h after the intervention (P = 0.008). No significant differences in the plasma time-concentration curves were observed between the two interventions (P = 0.645). An estimate of the total increase in plasma ascorbate indicated complete uptake of the ingested vitamin C tablet and kiwifruit-derived vitamin C. There was an increase in urinary ascorbate excretion, relative to urinary creatinine, from two hours post intervention (P < 0.001). There was also a significant difference between the two interventions, with enhanced ascorbate excretion observed in the kiwifruit group (P = 0.016). Urinary excretion was calculated as ~40% and ~50% of the ingested dose from the vitamin C tablet and kiwifruit arms, respectively. Overall, our pharmacokinetic study has shown comparable relative bioavailability of kiwifruit-derived vitamin C and synthetic vitamin C. PMID:24284610

Effects of ruminally degradable starch levels on performance, nitrogen balance, and nutrient digestibility in dairy cows fed low corn-based starch diets.

PubMed

Luo, Guobin; Xu, Wenbin; Yang, Jinshan; Li, Yang; Zhang, Liyang; Wang, Yizhen; Lin, Cong; Zhang, Yonggen

2017-05-01

This trial was performed to examine the effects of ruminally degradable starch (RDS) levels in total mixed ration (TMR) with low corn-based starch on the milk production, whole-tract nutrient digestibility and nitrogen balance in dairy cows. Eight multiparous Holstein cows (body weight [BW]: 717±63 kg; days in milk [DIM]: 169±29) were assigned to a crossover design with two dietary treatments: a diet containing 62.3% ruminally degradable starch (% of total starch, low RDS) or 72.1% ruminally degradable starch (% of total starch, high RDS). Changes to the ruminally degradable levels were conducted by using either finely ground corn or steam-flaked corn as the starch component. The results showed that dry matter intake, milk yield and composition in dairy cows were not affected by dietary treatments. The concentration of milk urea nitrogen was lower for cows fed high RDS TMR than low RDS TMR. The whole-tract apparent digestibility of neutral detergent fiber, acid detergent fiber and crude protein decreased, and that of starch increased for cows fed high RDS TMR over those fed low RDS TMR, with no dietary effect on the whole-tract apparent digestibility of dry matter and organic matter. The proportion of urinary N excretion in N intake was lower and that of fecal N excretion in N intake was higher for cows fed high RDS TMR than those fed low RDS TMR. The N secretion in milk and the retention of N were not influenced by the dietary treatments. Total purine derivative was similar in cows fed high RDS TMR and low RDS TMR. Consequently, estimated microbial N flow to the duodenum was similar in cows fed high RDS TMR and low RDS TMR. Results of this study show that ruminally degradable starch levels can influence whole-tract nutrient digestibility and nitrogen balance in dairy cows fed low corn-based starch diets, with no influence on performance.

Bovine papillomavirus type 2 infects the urinary bladder of water buffalo (Bubalus bubalis) and plays a crucial role in bubaline urothelial carcinogenesis.

PubMed

Roperto, Sante; Russo, Valeria; Ozkul, Ayhan; Sepici-Dincel, Aylin; Maiolino, Paola; Borzacchiello, Giuseppe; Marcus, Ioan; Esposito, Iolanda; Riccardi, Marita Georgia; Roperto, Franco

2013-02-01

Bovine papillomavirus type 2 (BPV-2) has been shown to infect and play a role in urinary bladder carcinogenesis of buffaloes grazed on pastures with ferns from the Marmara and Black Sea Regions of Turkey. BPV-2 DNA has been found in both neoplastic and non-neoplastic lesions of the urinary bladder. Furthermore, this virus may be a normal inhabitant of the urinary bladder since BPV-2 DNA has also been detected in clinically normal buffaloes. The viral activation by fern immunosuppressant or carcinogen may trigger the urothelial cell transformation. The E5 oncoprotein was solely detected in urothelial tumours and appeared to be co-localized with the overexpressed and phosphorylated platelet derived growth factor (PDGF) β receptor in a double-colour immunofluorescence assay. Our results indicate that the E5-PDGF β receptor interaction also occurs in spontaneous tumours of the bubaline urinary bladder, revealing an additional role of BPV-2 in bladder carcinogenesis of buffaloes.

Hydrogels Derived from Central Nervous System Extracellular Matrix

PubMed Central

Medberry, Christopher J.; Crapo, Peter M.; Siu, Bernard F.; Carruthers, Christopher A.; Wolf, Matthew T.; Nagarkar, Shailesh P.; Agrawal, Vineet; Jones, Kristen E.; Kelly, Jeremy; Johnson, Scott A.; Velankar, Sachin S.; Watkins, Simon C.; Modo, Michel

2012-01-01

Biologic scaffolds composed of extracellular matrix (ECM) are commonly used repair devices in preclinical and clinical settings; however the use of these scaffolds for peripheral and central nervous system (CNS) repair has been limited. Biologic scaffolds developed from brain and spinal cord tissue have recently been described, yet the conformation of the harvested ECM limits therapeutic utility. An injectable CNS-ECM derived hydrogel capable of in vivo polymerization and conformation to irregular lesion geometries may aid in tissue reconstruction efforts following complex neurologic trauma. The objectives of the present study were to develop hydrogel forms of brain and spinal cord ECM and compare the resulting biochemical composition, mechanical properties, and neurotrophic potential of a brain derived cell line to a non-CNS-ECM hydrogel, urinary bladder matrix. Results showed distinct differences between compositions of brain ECM, spinal cord ECM, and urinary bladder matrix. The rheologic modulus of spinal cord ECM hydrogel was greater than that of brain ECM and urinary bladder matrix. All ECMs increased the number of cells expressing neurites, but only brain ECM increased neurite length, suggesting a possible tissue-specific effect. All hydrogels promoted three-dimensional uni- or bi-polar neurite outgrowth following 7 days in culture. These results suggest that CNS-ECM hydrogels may provide supportive scaffolding to promote in vivo axonal repair. PMID:23158935

Purification and Characterization of the FeII- and α-Ketoglutarate-Dependent Xanthine Hydroxylase from Aspergillus nidulans†

PubMed Central

Montero-Morán, Gabriela M.; Li, Meng; Rendòn-Huerta, Erika; Jourdan, Fabrice; Lowe, David J.; Stumpff-Kane, Andrew W.; Feig, Michael; Scazzocchio, Claudio; Hausinger, Robert P.

2008-01-01

His6-tagged xanthine/α-ketoglutarate (αKG) dioxygenase (XanA) of Aspergillus nidulans was purified from both the fungal mycelium and recombinant Escherichia coli cells, and the properties of the two forms of the protein were compared. Evidence was obtained for both N- and O-linked glycosylation on the fungus-derived XanA, which aggregates into an apparent dodecamer, while bacteria-derived XanA is free of glycosylation and behaves as a monomer. Immunological methods identify phosphothreonine in both forms of XanA, with phosphoserine also detected in the bacteria-derived protein. Mass spectrometric analysis confirms glycosylation and phosphorylation of the fungus-derived sample, which also undergoes extensive truncation at its amino terminus. Despite the major differences in properties of these proteins, their kinetic parameters are similar (kcat 30-70 s-1, Km of αKG 31-50 μM, Km of xanthine ∼45 μM, and pH optima at 7.0 to 7.4). The enzyme exhibits no significant isotope effect when using 8-2H-xanthine; however, it demonstrates a two-fold solvent deuterium isotope effect. CuII and ZnII potently inhibit the FeII-specific enzyme, whereas CoII, MnII, and NiII are weaker inhibitors. NaCl decreases the kcat and increases the Km of both αKG and xanthine. The αKG cosubstrate can be substituted by α-ketoadipate (9-fold decrease in kcat and 5-fold increase in the Km compared to the normal α-keto acid), while the αKG analogue N-oxalylglycine is a competitive inhibitor (Ki 0.12 μM). No alternative purines effectively substitute for xanthine as a substrate, and only one purine analogue (6,8-dihydroxypurine) results in significant inhibition. Quenching of the endogenous fluorescence of the two enzyme forms by xanthine, αKG, and DHP was used to characterize their binding properties. A XanA homology model was generated on the basis of the structure of the related enzyme TauD (PDB code 1OS7) and provided insights into the sites of posttranslational modification and substrate binding. These studies represent the first biochemical characterization of purified xanthine/αKG dioxygenase. PMID:17429948

Carcinogen derived biomarkers: applications in studies of human exposure to secondhand tobacco smoke

PubMed Central

Hecht, S

2004-01-01

Objective: To review the literature on carcinogen derived biomarkers of exposure to secondhand tobacco smoke (SHS). These biomarkers are specifically related to known carcinogens in tobacco smoke and include urinary metabolites, DNA adducts, and blood protein adducts. Method: Published reviews and the current literature were searched for relevant articles. Results: The most consistently elevated biomarker in people exposed to SHS was 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides (NNAL-Gluc), urinary metabolites of the tobacco specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). The tobacco specificity of this biomarker as well as its clear relation to an established lung carcinogen are particularly appropriate for its application in studies of SHS exposure. Conclusion: The results of the available carcinogen derived biomarker studies provide biochemical data which support the conclusion, based on epidemiologic investigations, that SHS causes lung cancer in non-smokers. PMID:14985617

[Significance of 3-methoxytyramine urine measurement in the diagnosis of pheochromocytomas and paragangliomas: about 28 patients].

PubMed

Le Jacques, Aurélien; Abalain, Jean-Hervé; Le Saos, Fabienne; Carré, Jean-Luc

2011-01-01

Measurement of catecholamines derivatives is used to diagnose tumors such as pheochromocytomas and paragangliomas. Despite the low incidence of these diseases, their diagnosis is essential because of potentially lethal episodes of malignant hypertension related to an inappropriate secretion of catecholamines by these tumors. The catecholamines derivatives include 3-methoxytyramine, normetanephrine and metanephrine, assayed in urine or plasma. The significance of the measurement of urinary 3-methoxytyramine was addressed by analysing the records of 28 patients aged 25 to 84 years with isolated elevation of this derivative, with non-pathological urinary rates of metanephrine and normetanephrine, that might help suspect a catecholamine inappropriate secretion. In these situations, no pheochromocytoma or paraganglioma was diagnosed. This study, after discussing possible biases in the clinical care and diagnosis approach of these patients, raises the question of the relevance of this assay in the diagnostic management of these diseases.

Purine uptake in Plasmodium: transport versus metabolism.

PubMed

Kirk, Kiaran; Howitt, Susan M; Bröer, Stefan; Saliba, Kevin J; Downie, Megan J

2009-06-01

In a recent paper, Quashie et al. have proposed that purine uptake into the intraerythrocytic malaria parasite involves four different plasma membrane transporters - two high affinity and two low affinity. They equate one of the two high-affinity transporters with PfNT1, a transporter reported previously to be a low-affinity system. Here, we offer an alternative interpretation of their data, suggesting that the conclusions drawn by Quashie et al. take insufficient account of metabolism.

Chemical Carcinogen (Hydrazine et al.) Induced Carcinogenesis of Human Diploid Fibroblasts in vitro.

DTIC Science & Technology

1985-06-12

compound then is converted to a carbonium ion and the radical interacts /, with the purine bases in DNA. Methylazoxymethanol acetate, ( MAMA ) in the...interacts with the purine bases in DNA. Methylazoxymethanol acetate, ( MAMA ) in the presence of colon, secum and liver homogenates reduced NAD+ to NADH...3. Human foreskin fibroblast populations blocked in G1 , released and treated with methylazoxy methanol acetate ( MAMA ) from the time of

Determination of Caffeine and Other Purine Compounds in Food and Pharmaceuitcals by Micellar Electrokinetic Chrmoatography

NASA Astrophysics Data System (ADS)

Vogt, Carla; Contradi, S.; Rohde, E.

1997-09-01

Capillary elctrophoresis is a modern separation technique, especially the extremely high efficiencies and minimal requirements with regard to buffers, samples and solvents lead to a dramatic increase of applications in the last few years. This paper offers an introduction to the technique of micellar elektrokinetic chromatography as a special kind of capillary electrophoresis. Caffeine and other purine compounds have been determined in foodstuff (tea, coffee, cocoa) as well as in pharmaceutical formulations. Different sample preparation procedures which have been developed with regard to the special properties of the sample matrices are discussed in the paper.This preparation facilitates the separation in many cases. So students have to solve a relatively simple separation problem by variation of buffer pH, buffer components and separation parameters. By doing a calibration for the analyzed purine compounds they will learn about reproducibility in capillary electrophoresis.

Extraction of purine alkaloids from maté (Ilex paraguariensis) using supercritical CO(2).

PubMed

Saldaña, M D; Mohamed, R S; Baer, M G; Mazzafera, P

1999-09-01

Experimental data for the supercritical CO(2) extraction of purine alkaloids (caffeine, theobromine, and theophylline) from ground herbal maté tea (Ilex paraguaryensis) using a high-pressure apparatus are presented. Caffeine, theophylline, and theobromine were identified in the extracted fractions using HPLC. Results indicated a much higher CO(2) selectivity for caffeine in comparison with those for theophylline and theobromine. Solubilities of pure compounds in carbon dioxide were also determined at 313.2, 323.2, 338.2, and 343.2 K, and pressures ranging from 14 to 24 MPa. Caffeine solubility exhibited a retrograde behavior with temperature while theophylline and theobromine manifested a normal behavior at conditions explored in this study. Solubilities in binary CO(2)/purine alkaloid model systems were much higher than those obtained during extraction of maté tea, demonstrating the difficulty of using binary data in predicting complex multicomponent behavior.

Theacrine, a special purine alkaloid with sedative and hypnotic properties from Cammelia assamica var. kucha in mice.

PubMed

Xu, Jie-Kun; Kurihara, Hiroshi; Zhao, Liang; Yao, Xin-Sheng

2007-01-01

The central nervous system activities of theacrine (1,3,7,9-tetramethyluric acid), a purine alkaloid which is abundantly present in Camellia assamica var. kucha, were investigated in ambulatory activity, pentobarbital-induced sleep and forced swimming test in mice, compared with two other purine alkaloids, caffeine and theobromine. Caffeine treatment led to a marked increase in the ambulatory activity accompanied with decreasing of the immobility time in forced swimming test at both 10 and 30 mg/kg. Under the same conditions, neither theacrine nor theobromine showed obvious excited efficacy. Both doses of theacrine could significantly prolong the sleeping time induced by pentobarbital, while caffeine and theobromine exhibited an inverted effect. These results indicated that theacrine possessed potent sedative and hypnotic properties and its central nervous system effects were different from those of caffeine and theobromine.

The immunosuppressives FK 506 and cyclosporin A inhibit the generation of protein factors binding to the two purine boxes of the interleukin 2 enhancer.

PubMed Central

Brabletz, T; Pietrowski, I; Serfling, E

1991-01-01

Like Cyclosporin A (CsA), the macrolide FK 506 is a potent immunosuppressive that inhibits early steps of T cell activation, including the synthesis of Interleukin 2 (II-2) and numerous other lymphokines. The block of II-2 synthesis occurs at the transcriptional level. At concentrations that block T cell activation, FK 506 and CsA inhibit the proto-enhancer activity of Purine boxes of the II-2 promoter and the generation of lymphocyte-specific factors binding to the Purine boxes. Under the same conditions, the DNA binding of other II-2 enhancer factors remains unaffected by both compounds. These results support the view that FK 506 and CsA, which both inhibit the activity of peptidylprolyl cis/trans isomerases, suppress T cell activation by a similar, if not identical mechanism. Images PMID:1707162

The immunosuppressives FK 506 and cyclosporin A inhibit the generation of protein factors binding to the two purine boxes of the interleukin 2 enhancer.

PubMed

Brabletz, T; Pietrowski, I; Serfling, E

1991-01-11

Like Cyclosporin A (CsA), the macrolide FK 506 is a potent immunosuppressive that inhibits early steps of T cell activation, including the synthesis of Interleukin 2 (II-2) and numerous other lymphokines. The block of II-2 synthesis occurs at the transcriptional level. At concentrations that block T cell activation, FK 506 and CsA inhibit the proto-enhancer activity of Purine boxes of the II-2 promoter and the generation of lymphocyte-specific factors binding to the Purine boxes. Under the same conditions, the DNA binding of other II-2 enhancer factors remains unaffected by both compounds. These results support the view that FK 506 and CsA, which both inhibit the activity of peptidylprolyl cis/trans isomerases, suppress T cell activation by a similar, if not identical mechanism.

Association of bladder sensation measures and bladder diary in patients with urinary incontinence.

PubMed

King, Ashley B; Wolters, Jeff P; Klausner, Adam P; Rapp, David E

2012-04-01

Investigation suggests the involvement of afferent actions in the pathophysiology of urinary incontinence. Current diagnostic modalities do not allow for the accurate identification of sensory dysfunction. We previously reported urodynamic derivatives that may be useful in assessing bladder sensation. We sought to further investigate these derivatives by assessing for a relationship with 3-day bladder diary. Subset analysis was performed in patients without stress urinary incontinence (SUI) attempting to isolate patients with urgency symptoms. No association was demonstrated between bladder diary parameters and urodynamic derivatives (r coefficient range (-0.06 to 0.08)(p > 0.05)). However, subset analysis demonstrated an association between detrusor overactivity (DO) and bladder urgency velocity (BUV), with a lower BUV identified in patients without DO. Subset analysis of patients with isolated urgency/urge incontinence identified weak associations between voiding frequency and FSR (r = 0.39) and between daily incontinence episodes and BUV (r = 0.35). However, these associations failed to demonstrate statistical significance. No statistical association was seen between bladder diary and urodynamic derivatives. This is not unexpected, given that bladder diary parameters may reflect numerous pathologies including not only sensory dysfunction but also SUI and DO. However, weak associations were identified in patients without SUI and, further, a statistical relationship between DO and BUV was seen. Additional research is needed to assess the utility of FSR/BUV in characterizing sensory dysfunction, especially in patients without concurrent pathology (e.g. SUI, DO).

Vector Flow Visualization of Urinary Flow Dynamics in a Bladder Outlet Obstruction Model.

PubMed

Ishii, Takuro; Yiu, Billy Y S; Yu, Alfred C H

2017-11-01

Voiding dysfunction that results from bladder outlet (BO) obstruction is known to alter significantly the dynamics of urine passage through the urinary tract. To non-invasively image this phenomenon on a time-resolved basis, we pursued the first application of a recently developed flow visualization technique called vector projectile imaging (VPI) that can track the spatiotemporal dynamics of flow vector fields at a frame rate of 10,000 fps (based on plane wave excitation and least-squares Doppler vector estimation principles). For this investigation, we designed a new anthropomorphic urethral tract phantom to reconstruct urinary flow dynamics under controlled conditions (300 mm H 2 O inlet pressure and atmospheric outlet pressure). Both a normal model and a diseased model with BO obstruction were developed for experimentation. VPI cine loops were derived from these urinary flow phantoms. Results show that VPI is capable of depicting differences in the flow dynamics of normal and diseased urinary tracts. In the case with BO obstruction, VPI depicted the presence of BO flow jet and vortices in the prostatic urethra. The corresponding spatial-maximum flow velocity magnitude was estimated to be 2.43 m/s, and it is significantly faster than that for the normal model (1.52 m/s) and is in line with values derived from computational fluid dynamics simulations. Overall, this investigation demonstrates the feasibility of using vector flow visualization techniques to non-invasively examine internal flow characteristics related to voiding dysfunction in the urethral tract. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Flowering in Vitis: Conversion of tendrils into inflorescences and bunches of grapes.

PubMed

Srinivasan, C; Mullins, M G

1979-01-01

Inflorescences and fruits with viable seeds were produced in place of tendrils in plants of Vitis vinifera L. cv. "Muscat of Alexandria" and in a staminate hybrid grapevine (Vitis vinifera x V. rupestris Scheele) following repeated applications of 10-20 μl of 50-200 μM 6-(benzylamino)-9-(2-tetrahydropyranyl)-9H-purine (PBA) to apices. Young leaves, shoot tips and axillary buds were removed before the PBA treatments were commenced. The number and weight of berries produced by inflorescences derived from tendrils was closely correlated with the number and area of leaves retained. When application of PBA was continued after floral initiation there was formation of fused flowers and cleistogamous pollination.

Exposure to 4,4'-methylenediphenyl diisocyanate (MDI) during moulding of rigid polyurethane foam: determination of airborne MDI and urinary 4,4'-methylenedianiline (MDA).

PubMed

Kääriä, K; Hirvonen, A; Norppa, H; Piirilä, P; Vainio, H; Rosenberg, C

2001-04-01

Occupational exposure to 4,4'-methylenediphenyl diisocyanate (MDI) was measured during moulding of rigid polyurethane foam. The aim of the study was to find out whether an MDI-derived urinary amine metabolite could be detected in the urine of workers exposed to apparently low levels of MDI. Airborne MDI was sampled on 1-(2-methoxyphenyl)-piperazine (2MP)-impregnated glass fibre filters and determined by high-performance liquid chromatography (HPLC) using ultraviolet (UV) and electrochemical (EC) detection. The limit of detection of MDI was 3 ng ml-1 for a 20 microliters injection. The precision of sample preparation, expressed as relative standard deviation (RSD), was 1.3% with UV detection and 2.1% with EC detection at a concentration of 70 ng MDI ml-1 (n = 6). The 2MP-MDI derivative was stable at +4 degrees C up to eight weeks. The accuracy of the method was validated in an international quality control programme. Workers (n = 57) from three different factories participated in the study. Urinary 4,4'-methylenedianiline (MDA) metabolite was determined after acid hydrolysis as heptafluorobutyric anhydride derivatives by gas chromatography-mass spectrometry using chemical ionisation and monitoring negative ions. The limit of detection in urine was 0.2 nmol l-1. The precision of six analyses for a urine sample spiked to a concentration of 1 nmol l-1 was 29% (RSD). The MDI concentrations were below the limit of detection in most (64%) of the air samples collected in the worker's breathing zone. Still, detectable amounts of MDA were found in 97% of the urine samples. Monitoring of urinary MDA appears to be an appropriate method of assessing MDI exposure in work environments with low or undetectable MDI concentrations in the workplace air.

Paraganglioma of the Urinary Bladder: A Rare Cause of Hypertension and Urinary Tract Infections.

PubMed

Chaaya, Gerard; Morales, Jorge; Castiglioni, Analia; Subhani, Noman; Asmar, Abdo

2018-02-01

Pheochromocytoma is a neoplasm, which develops from cells of the chromaffin tissues that are derived from the ectodermic neural system and mostly situated within the adrenal medulla. Approximately 15% of pheochromocytoma cases arise from extra-adrenal chromaffin tissue. Pheochromocytoma of the bladder is rare and accounts for less than 0.06% of all bladder neoplasms and less than 1% of all pheochromocytomas. We report a case of a young woman who presented with uncontrolled hypertension, recurrent urinary tract infections and micturition attacks and was found to have a metastatic bladder paraganglioma. In addition, we provide a summary table of the clinical manifestations of paragangliomas based on anatomic locations. Published by Elsevier Inc.

Carboxymethyl- and carboxyl-catechins from ripe Pu-er tea.

PubMed

Tian, Li-Wen; Tao, Mu-Ke; Xu, Min; Hu, Jing; Zhu, Hong-Tao; Xiong, Wen-Yong; Wang, Dong; Yang, Chong-Ren; Zhang, Ying-Jun

2014-12-17

Ripe Pu-er tea, a special microbial postfermented tea originated from Yunnan Province, China, since ancient times, is made from green Pu-er tea prepared from the leaves of Camellia sinensis var. assamica (Theaceae). Chemical investigation on thearubigin (n-BuOH-soluble) fraction of the commercial ripe Pu-er tea, led to the identification of four new flavan-3-ol derivatives, 8-carboxymethyl-(+)-catechin (1), 8-carboxymethyl-(+)-catechin methyl ester (2), 6-carboxymethyl-(+)-catechin (3), and 6-carboxyl-(-)-gallocatechin (4), together with 18 known compounds, including other three flavan-3-ol derivatives (5-7), 10 flavonoid glycosides (8-17), two hydrolyzable tannins (18 and 19), two quinic acid derivatives (20-21), and a purine alkaloid (22). Flavonoid glycosides 8-11 are reported from tea plants for the first time. The thearubigin fraction of ripe Pu-er tea was qualitatively analyzed by HPLC, and gallic acid was found to be the major component. Compounds 4, 6-17, 21 and 22 were tested for their acute activities on insulin sensitivity in differentiated 3T3-L1 adipocytes, but none of them showed significant bioactivity at a concentration of 10 μM.

Purine-related metabolites and their converting enzymes are altered in frontal, parietal and temporal cortex at early stages of Alzheimer's disease pathology.

PubMed

Alonso-Andrés, Patricia; Albasanz, José Luis; Ferrer, Isidro; Martín, Mairena

2018-01-24

Adenosine, hypoxanthine, xanthine, guanosine and inosine levels were assessed by HPLC, and the activity of related enzymes 5'-nucleotidase (5'-NT), adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) measured in frontal (FC), parietal (PC) and temporal (TC) cortices at different stages of disease progression in Alzheimer's disease (AD) and in age-matched controls. Significantly decreased levels of adenosine, guanosine, hypoxanthine and xanthine, and apparently less inosine, are found in FC from the early stages of AD; PC and TC show an opposing pattern, as adenosine, guanosine and inosine are significantly increased at least at determinate stages of AD whereas hypoxanthine and xanthine levels remain unaltered. 5'-NT is reduced in membranes and cytosol in FC mainly at early stages but not in PC, and only at advanced stages in cytosol in TC. ADA activity is decreased in AD when considered as a whole but increased at early stages in TC. Finally, PNP activity is increased only in TC at early stages. Purine metabolism alterations occur at early stages of AD independently of neurofibrillary tangles and β-amyloid plaques. Alterations are stage dependent and region dependent, the latter showing opposite patterns in FC compared with PC and TC. Adenosine is the most affected of the assessed purines. © 2018 International Society of Neuropathology.

Relative similarity within purine nucleotide and ligand structures operating on nitric oxide synthetase, guanylyl cyclase and potassium (K ATP, BK Ca) channels.

PubMed

Williams, W Robert

2011-01-01

Purine nucleotides play a central role in signal transduction events initiated at the cell membrane. The NO-cGMP-cGK pathway, in particular, mediates events involving NOS and some classes of K(+) ion channel. The aim of this study is to investigate relative molecular similarity within the ligands binding to NOS, K(ATP), BK(Ca) channels and regulatory nucleotides. Minimum energy conformers of the ligand structures were superimposed and fitted to L-arginine and the nucleotides of adenine and guanine using a computational program. Distinctive patterns were evident in the fitting of NOS isoform antagonists to L-arginine. K(ATP) channel openers and antagonists superimposed on the glycosidic linkage and imidazole ring of the purine nucleotides, and guanidinium and ribose groups of GTP in the case of glibenclamide. The fits of BK(Ca) channel openers and antagonists to cGMP were characterized by the linear dimensions of their structures; distances between terminal oxy groups in respect of dexamethasone and aldosterone. The findings provide structural evidence for the functional interaction between K(+) channel openers/antagonists and the regulatory nucleotides. Use of the purine nucleotide template systematizes the considerable heterogeneity evident within the structures of ligands operating on K(+) ion channels. © 2010 The Author. JPP © 2010 Royal Pharmaceutical Society.

Regeneration of Stevia Plant Through Callus Culture

PubMed Central

Patel, R. M.; Shah, R. R.

2009-01-01

Stevia rebaudiana Bertoni that conventionally propagated by seed or by cuttings or clump division which has a limitation of quality and quantity seed material. In present study, callus culture technique was tried to achieve rapid plant multiplication for quality seed material. Callus induction and multiplication medium was standardized from nodal as well as leaf sagments. It is possible to maintain callus on Murashige and Skoog medium supplemented with 6-benzyl amino purine and naphthalene acetic acid. Maximum callus induction was obtained on Murashige and Skoog medium incorporated with 6-benzyl amino purine (2.0-3.0 mg/l) and naphthalene acetic acid (2.0 mg/l) treatments. However, Murashige and Skoog medium containing 2.0 mg/l 6-benzyl amino purine+2.0 mg/l naphthalene acetic acid was found to be the best for callus induction. Higher regeneration frequency was noticed with Murashige and Skoog medium supplemented with 2.0 mg/l 6-benzyl amino purine+0.2 mg/l naphthalene acetic acid. Regenerated plants were rooted better on ¼ Murashige and Skoog strength supplemented with 0.1 mg/l indole-3-butyric acid. The rooted plantlets were hardened successfully in tera care medium with 63 per cent survival rate. The developed protocol can be utilized for mass production of true to type planting material on large scale independent of season, i.e. external environmental conditions. PMID:20177455

Role and regulation of coordinately expressed de novo purine biosynthetic enzymes PPAT and PAICS in lung cancer.

PubMed

Goswami, Moloy T; Chen, Guoan; Chakravarthi, Balabhadrapatruni V S K; Pathi, Satya S; Anand, Sharath K; Carskadon, Shannon L; Giordano, Thomas J; Chinnaiyan, Arul M; Thomas, Dafydd G; Palanisamy, Nallasivam; Beer, David G; Varambally, Sooryanarayana

2015-09-15

Cancer cells exhibit altered metabolism including aerobic glycolysis that channels several glycolytic intermediates into de novo purine biosynthetic pathway. We discovered increased expression of phosphoribosyl amidotransferase (PPAT) and phosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS) enzymes of de novo purine biosynthetic pathway in lung adenocarcinomas. Transcript analyses from next-generation RNA sequencing and gene expression profiling studies suggested that PPAT and PAICS can serve as prognostic biomarkers for aggressive lung adenocarcinoma. Immunohistochemical analysis of PAICS performed on tissue microarrays showed increased expression with disease progression and was significantly associated with poor prognosis. Through gene knockdown and over-expression studies we demonstrate that altering PPAT and PAICS expression modulates pyruvate kinase activity, cell proliferation and invasion. Furthermore we identified genomic amplification and aneuploidy of the divergently transcribed PPAT-PAICS genomic region in a subset of lung cancers. We also present evidence for regulation of both PPAT and PAICS and pyruvate kinase activity by L-glutamine, a co-substrate for PPAT. A glutamine antagonist, 6-Diazo-5-oxo-L-norleucine (DON) blocked glutamine mediated induction of PPAT and PAICS as well as reduced pyruvate kinase activity. In summary, this study reveals the regulatory mechanisms by which purine biosynthetic pathway enzymes PPAT and PAICS, and pyruvate kinase activity is increased and exposes an existing metabolic vulnerability in lung cancer cells that can be explored for pharmacological intervention.

Folate restriction and methylenetetrahydrofolate reductase 677T polymorphism decreases adoMet synthesis via folate-dependent remethylation in human-transformed lymphoblasts.

PubMed

Chiang, E-P; Wang, Y-C; Tang, F-Y

2007-04-01

The homozygous mutation (677TT) in the methylenetetrahydrofolate reductase (MTHFR) gene reduces enzyme activity and alters cellular folate composition. Previous epidemiological studies reported a potential protective effect of MTHFR677C --> T against acute lymphocytic leukemia and malignant lymphoma, but the mechanism remains to be determined. We investigated the biochemical impacts of MTHFR677C --> T on cellular S-adenosyl methionine (adoMet) synthesis, global DNA methylation, and de novo purine synthesis, all of which are potential regulatory pathways involved in tumorigenesis. Metabolic fluxes of homocysteine remethylation and de novo purine synthesis were compared between Epstein-Barr virus-transformed lymphoblasts expressing MTHFR 677C and MTHFR 677T using stable isotopic tracers and GCMS. MTHFR TT genotype significantly reduced folate-dependent remethylation under folate restriction, reflecting limited methylated folates under folate restriction. Data also suggested increased formylated folate pool and increased purine synthesis when folate is adequate. The impacts of MTHFR 677T polymorphism appeared closely related to folate status, and such alterations may modulate metabolic pathways involved in cancer onset/progression. The advantage of de novo purine synthesis found in the MTHFR TT genotype may account for the protective effect of MTHFR in hematological malignancies. These transformed cells are potential models for studying the consequences of human genetic variation and cancer pathogenesis.

Penetration of theophylline and adenosine into excised human skin from binary and ternary vehicles: effect of a nonionic surfactant.

PubMed

Kadir, R; Stempler, D; Liron, Z; Cohen, S

1989-02-01

A nonionic surfactant, diethyleneglycol lauryl ether (PEG-2-L), increases the flux of either theophylline or adenosine by a factor of 2.2-2.7, when these are delivered from propionic acid solutions into human skin samples, with respect to propionic acid alone. At the same time, the flux of propionic acid from the same vehicles is decreased. Significant expansion of the partial molal volumes vi of both purines occurs following incorporation of PEG-2-L into their propionic acid solution. Hence, the enhancing effect of this surfactant arises mainly from an increase in the excess free energy of these solutes in the donor phase ("push" effect). Paraffin oil increases the flux of either drug from propionic acid by an entirely different mechanism. It enhances the flux of propionic acid into the skin, thus promoting the partitioning of the purine solute in the modified skin barrier ("pull" effect). Indeed, the magnitude of vi of either purine in propionic acid:paraffin oil solution gives no indication of a significant interaction between paraffin oil and the purine solute. Finally, the penetration enhancing effects of PEG-2-L and paraffin oil combined together in the same propionic acid vehicle are additive, resulting in a flux which is approximately the sum total of fluxes obtained separately with PEG-2-L or paraffin oil.

Synthesis of conformationally locked L-deoxythreosyl phosphonate nucleosides built on a bicyclo[3.1.0]hexane template.

PubMed

Saneyoshi, Hisao; Deschamps, Jeffrey R; Marquez, Victor E

2010-11-19

Two conformationally locked versions of l-deoxythreosyl phosphonate nucleosides (2 and 3) were synthesized to investigate the preference of HIV reverse transcriptase for a conformation displaying either a fully diaxial or fully diequatorial disposition of substituents. Synthesis of the enantiomeric 4-(6-amino-9H-purin-9-yl)bicyclo[3.1.0]hexan-2-ol carbocyclic nucleoside precursors (diaxially disposed) proceeded straightforwardly from commercially available (1R,4S)-4-hydroxy-2-cyclopent-2-enyl-1-yl acetate employing a hydroxyl-directed Simmons-Smith cyclopropanation that culminated with a Mitsunobu coupling of the purine base. For the more complicated 1-(6-amino-9H-purin-9-yl)bicyclo[3.1.0]hexan-3-ol carbocyclic nucleoside precursors (diequatorially disposed), the obligatory linear approach required the syntheses of key 1-aminobicyclo[3.1.0.]hexan-3-yl benzoate precursors that were assembled via the amide variant of the Kulinkovich reaction involving the intramolecular cyclopropanation of a substituted δ-vinylamide. Completion of the purine ring was achieved by conventional approaches but with much improved yields through the use of a microwave reactor. The syntheses of the phosphonates and the corresponding diphosphates were achieved by conventional means. None of the diphosphates, which were supposed to act as nucleoside triphosphate mimics, could compete with dATP even when present in a 10-fold excess.

Crystal Structure of Schistosoma mansoni Adenosine Phosphorylase/5’-Methylthioadenosine Phosphorylase and Its Importance on Adenosine Salvage Pathway

PubMed Central

Torini, Juliana Roberta; Brandão-Neto, José; DeMarco, Ricardo; Pereira, Humberto D'Muniz

2016-01-01

Schistosoma mansoni do not have de novo purine pathways and rely on purine salvage for their purine supply. It has been demonstrated that, unlike humans, the S. mansoni is able to produce adenine directly from adenosine, although the enzyme responsible for this activity was unknown. In the present work we show that S. mansoni 5´-deoxy-5´-methylthioadenosine phosphorylase (MTAP, E.C. 2.4.2.28) is capable of use adenosine as a substrate to the production of adenine. Through kinetics assays, we show that the Schistosoma mansoni MTAP (SmMTAP), unlike the mammalian MTAP, uses adenosine substrate with the same efficiency as MTA phosphorolysis, which suggests that this enzyme is part of the purine pathway salvage in S. mansoni and could be a promising target for anti-schistosoma therapies. Here, we present 13 SmMTAP structures from the wild type (WT), including three single and one double mutant, and generate a solid structural framework for structure description. These crystal structures of SmMTAP reveal that the active site contains three substitutions within and near the active site when compared to it mammalian counterpart, thus opening up the possibility of developing specific inhibitors to the parasite MTAP. The structural and kinetic data for 5 substrates reveal the structural basis for this interaction, providing substract for inteligent design of new compounds for block this enzyme activity. PMID:27935959

Current state of the art for enhancing urine biomarker discovery

PubMed Central

Harpole, Michael; Davis, Justin; Espina, Virginia

2016-01-01

Urine is a highly desirable biospecimen for biomarker analysis because it can be collected recurrently by non-invasive techniques, in relatively large volumes. Urine contains cellular elements, biochemicals, and proteins derived from glomerular filtration of plasma, renal tubule excretion, and urogenital tract secretions that reflect, at a given time point, an individual's metabolic and pathophysiologic state. High-resolution mass spectrometry, coupled with state of the art fractionation systems are revealing the plethora of diagnostic/prognostic proteomic information existing within urinary exosomes, glycoproteins, and proteins. Affinity capture pre-processing techniques such as combinatorial peptide ligand libraries and biomarker harvesting hydrogel nanoparticles are enabling measurement/identification of previously undetectable urinary proteins. Future challenges in the urinary proteomics field include a) defining either single or multiple, universally applicable data normalization methods for comparing results within and between individual patients/data sets, and b) defining expected urinary protein levels in healthy individuals. PMID:27232439

Urinary Calcium and Oxalate Excretion in Healthy Adult Cats Are Not Affected by Increasing Dietary Levels of Bone Meal in a Canned Diet

PubMed Central

Passlack, Nadine; Zentek, Jürgen

2013-01-01

This study aimed to investigate the impact of dietary calcium (Ca) and phosphorus (P), derived from bone meal, on the feline urine composition and the urinary pH, allowing a risk assessment for the formation of calcium oxalate (CaOx) uroliths in cats. Eight healthy adult cats received 3 canned diets, containing 12.2 (A), 18.5 (B) and 27.0 g Ca/kg dry matter (C) and 16.1 (A), 17.6 (B) and 21.1 g P/kg dry matter (C). Each diet was fed over 17 days. After a 7 dayś adaptation period, urine and faeces were collected over 2×4 days (with a two-day rest between), and blood samples were taken. Urinary and faecal minerals, urinary oxalate (Ox), the urinary pH and the concentrations of serum Ca, phosphate and parathyroid hormone (PTH) were analyzed. Moreover, the urine was microscopically examined for CaOx uroliths. The results demonstrated that increasing levels of dietary Ca led to decreased serum PTH and Ca and increased faecal Ca and P concentrations, but did not affect the urinary Ca or Ox concentrations or the urinary fasting pH. The urinary postprandial pH slightly increased when the diet C was compared to the diet B. No CaOx crystals were detected in the urine of the cats. In conclusion, urinary Ca excretion in cats seems to be widely independent of the dietary Ca levels when Ca is added as bone meal to a typical canned diet, implicating that raw materials with higher contents of bones are of subordinate importance as risk factors for the formation of urinary CaOx crystals. PMID:23940588

Urinary Biomarkers and Obstructive Sleep Apnea in Patients with Down Syndrome

PubMed Central

Elsharkawi, Ibrahim; Gozal, David; Macklin, Eric A.; Voelz, Lauren; Weintraub, Gil; Skotko, Brian G.

2017-01-01

Study Objectives The study aim was to compare urinary biomarkers in individuals with Down syndrome (DS) with and without obstructive sleep apnea (OSA) to those of age- and sex-matched neurotypically developing healthy controls (HC). We further investigated whether we could predict OSA in individuals with DS using these biomarkers. Methods Urine samples were collected from 58 individuals with DS the night before or the morning after their scheduled overnight polysomnogram or both, of whom 47 could be age- and sex-matched to a sample of 43 HC. Concentrations of 12 neurotransmitters were determined by enzyme-linked immunosorbent assay. Log-transformed creatinine-corrected assay levels were normalized. Normalized z-scores were compared between individuals with DS vs. HC, between individuals with DS with vs. without OSA, and to derive composite models to predict OSA. Results Most night-sampled urinary biomarkers were elevated among individuals with DS relative to matched HC. No urinary biomarker levels differed between individuals with DS with vs. without OSA. A combination of four urinary biomarkers predicted AHI > 1 with a positive predictive value of 90% and a negative predictive value of 68%. Conclusions Having DS, even in the absence of concurrent OSA, is associated with a different urinary biomarker profile when compared to HC. Therefore, while urinary biomarkers may be predictive of OSA in the general pediatric population, a different approach is needed in interpreting urinary biomarker assays in individuals with DS. Certain biomarkers also seem promising to be predictive of OSA in individuals with DS. PMID:28522103

Scaffold hopping identifies 6,8-disubstituted purines as novel anaplastic lymphoma kinase inhibitors.

PubMed

Schlütke, Laura; Immer, Markus; Preu, Lutz; Totzke, Frank; Schächtele, Christoph; Kubbutat, Michael H G; Kunick, Conrad

2018-05-01

Rearrangements of anaplastic lymphoma kinase (ALK) are associated with several cancer diseases. Due to resistance development against existing ALK-inhibitors, new, structurally unrelated inhibitors are required. By a scaffold hopping strategy, 6,8-disubstituted purines were designed as analogues of similar ALK-inhibiting thieno[3,2-d]pyrimidines. While the new title compounds indeed inhibited ALK and several ALK mutants in submicromolar concentrations, they retained poor water solubility. Copyright © 2017 Elsevier B.V. All rights reserved.

Polymeric film of 6-arm-poly(ethylene glycol) amine graphene oxide with poly (ε-caprolactone): Adherence and growth of adipose derived mesenchymal stromal cells culture on rat bladder

NASA Astrophysics Data System (ADS)

Durán, Marcela; Durán, Nelson; Luzo, Angela C. M.; Duarte, Adriana S. S.; Volpe, Bruno B.; Ceragioli, Helder J.; Andrade, Patricia F.; De Souza, Joel G.; Fávaro, Wagner J.

2017-06-01

Nanotechnology has been more present in different fields related to health. The need to find a durable material, of easy use, and which does not interfere significantly in the growth and differentiation of stem cells for the construction of a scaffold for use in urologic surgery, with the purpose of reducing infections, regeneration times and even graft rejection during reconstitution in patients with urethral stricture was conducted a broad survey of information about this and came to the consensus of this project: using graphene oxide, a widely studied nanomaterials which has been presenting numerous beneficial results when in contact with the adipose-derived stem cells. Advanced techniques for the growth, differentiation and proliferation of adipose-derived stem cells were used, as well as the characterization of graphene oxide sheets. For this study, it was prepared the graphene oxide/6 ARM-Poly (ethylene glycol) amine films with poly (ε-caprolactone). The graphene suspension in organic solvent was prepared by using an ultrasonicator bath and subsequently, the film was formed by solvent evaporation. Total characterization of graphene oxide/6 ARM-PEG-amine/ poly (ε-caprolactone) film was carried out. It was tested growth and adhesion of adipose-derived stem cells on the film, as well as, were verified the histopathological effects of this scaffold when implanted in the urinary bladder to repair the lesion. Our results demonstrated that this scaffold with adipose-derived stem cells enhanced the repair in rat urinary bladder defect model, resulting in a regular bladder. Improved organized muscle bundles and urothelial layer were observed in animals treated with this scaffold with adipose-derived stem cells compared with those treated only suture thread or scaffold. Thus, our biomaterial could be suitable for tissue engineered urinary tract reconstruction.

Sequencing of adenine in DNA by scanning tunneling microscopy

NASA Astrophysics Data System (ADS)

Tanaka, Hiroyuki; Taniguchi, Masateru

2017-08-01

The development of DNA sequencing technology utilizing the detection of a tunnel current is important for next-generation sequencer technologies based on single-molecule analysis technology. Using a scanning tunneling microscope, we previously reported that dI/dV measurements and dI/dV mapping revealed that the guanine base (purine base) of DNA adsorbed onto the Cu(111) surface has a characteristic peak at V s = -1.6 V. If, in addition to guanine, the other purine base of DNA, namely, adenine, can be distinguished, then by reading all the purine bases of each single strand of a DNA double helix, the entire base sequence of the original double helix can be determined due to the complementarity of the DNA base pair. Therefore, the ability to read adenine is important from the viewpoint of sequencing. Here, we report on the identification of adenine by STM topographic and spectroscopic measurements using a synthetic DNA oligomer and viral DNA.

Chlorambucil for the treatment of patients with chronic lymphocytic leukemia (CLL) - a systematic review and meta-analysis of randomized trials.

PubMed

Vidal, Liat; Gurion, Ronit; Ram, Ron; Raanani, Pia; Bairey, Osnat; Robak, Tadeusz; Gafter-Gvili, Anat; Shpilberg, Ofer

2016-09-01

Randomized clinical trials that compared chlorambucil to different regimens, for patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) do not support an overall survival (OS) benefit. To assess the efficacy and safety of chlorambucil as frontline treatment, we conducted a systematic review and meta-analysis of randomized controlled trials. OS was the primary outcome. Meta-analysis of 18 trials that compared purine analogs, alkylators, alemtuzumab and ibrutinib to chlorambucil demonstrated no OS benefit for therapy without chlorambucil over chlorambucil (pooled HR 0.99, 95% CI 0.91-1.08; 4133 patients). PFS was longer with purine analogs compared with chlorambucil with an increased risk of infection. The risk of secondary malignancies was not increased with chlorambucil. In conclusion, our study showed that chlorambucil is an acceptable chemotherapy backbone for unfit patients with CLL. Purine analogs should be preferred in fit younger patients because of longer PFS. Future trials should focus on unfit patients who are underrepresented in clinical trials.

Structural characterization of purine nucleoside phosphorylase from human pathogen Helicobacter pylori.

PubMed

Štefanić, Zoran; Mikleušević, Goran; Luić, Marija; Bzowska, Agnieszka; Leščić Ašler, Ivana

2017-08-01

Microaerophilic bacterium Helicobacer pylori is a well known human pathogen involved in the development of many diseases. Due to the evergrowing infection rate and increase of H. pylori antibiotic resistence, it is of utmost importance to find a new way to attack and eradicate H. pylori. The purine metabolism in H. pylori is solely dependant on the salvage pathway and one of the key enzymes in this pathway is purine nucleoside phosphorylase (PNP). In this timely context, we report here the basic biochemical and structural characterization of recombinant PNP from the H. pylori clinical isolate expressed in Escherichia coli. Structure of H. pylori PNP is typical for high molecular mass PNPs. However, its activity towards adenosine is very low, thus resembling more that of low molecular mass PNPs. Understanding the molecular mechanism of this key enzyme may lead to the development of new drug strategies and help in the eradication of H. pylori. Copyright © 2017 Elsevier B.V. All rights reserved.

Nucleotide and nucleoside involvement in immunomodulation in experimental Chagas disease.

PubMed

do Carmo, Guilherme M; de Sá, Mariângela F; Baldissera, Matheus D; Grando, Thirssa H; Mendes, Ricardo E; Cardoso, Valesca V; Casali, Emerson A; Moritz, Cesar Eduardo J; Monteiro, Silvia G; Da Silva, Aleksandro S

2018-02-05

The aim of this study was to evaluate whether Trypanosma cruzi infections cause alterations in the levels of seric purines, which could contribute to host immunomodulation. Twelve mice were divided into two groups identified as control (uninfected) and infected (T. cruzi) groups. The influence of the disease on seric purine levels was verified on day 20 post-infection (PI) by HPLC. Infected mice had circulating trypomastigotes during the experiment, as well as amastigote forms in the heart associated with inflammatory infiltrates. Increases on adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine (ADO), inosine (INO), and uric acid (URIC) levels were observed in the infected animals, while the adenosine monophosphate (AMP) and xanthine (XAN) levels were reduced compared with mice of the control group, indicating a possible impairment on the purinergic system, and consequently, on the immune system during the clinical course of the disease. In summary, the T. cruzi infection alters the seric purine levels, and consequently, modulates the immune system.

Current Therapy and New Directions in the Treatment of Hairy Cell Leukemia: A Review.

PubMed

Sarvaria, Aditya; Topp, Zheng; Saven, Alan

2016-01-01

Hairy cell leukemia (HCL) is a chronic B-cell leukemia noted for an indolent course that ultimately results in cytopenias and massive splenomegaly. Whereas treatment with the nucleoside purine analogues cladribine and pentostatin results in lengthy remissions in nearly all patients with HCL, most patients will experience relapse while a small percentage of patients' disease fails to respond to therapy in the first place. Retreatment with a purine nucleoside analogue often leads to an effective but limited response. For decades, few other viable therapeutic options were available to these patients who required retreatment. Recently, new insights into the mechanism of disease of HCL have led to research in new potential treatment agents, either alone or with a purine nucleoside analogue. Clinical trials with rituximab, bendamustine, and conjugate immunotoxins will reveal what role these therapies will have in HCL treatment. A better understanding of the BRAF/MEK/ERK pathway and the B-cell signaling pathway has allowed further exploration into the novel drugs vemurafenib, dabrafenib, trametinib, and ibrutinib.

[The role of urinary markers in the assessment and follow-up of lower urinary tract disorders: a literature review].

PubMed

Peyronnet, B; Bendavid, C; Manunta, A; Damphousse, M; Cheensse, C; Brochard, C; Castel-Lacanal, E; Siproudhis, L; Bensalah, K; Gamé, X

2015-03-01

To conduct a literature review on the role of urinary biomarkers in the initial assessment and follow-up of lower urinary tract symptoms. A literature review was conducted in August 2014 using the Medline/Pubmed database limiting the search to work in English or French. Most studies were of level of evidence 2 or 3 (prospective cohort, controlled or not) and mainly about overactive bladder and bladder pain syndrome. Nerve Growth Factor (NGF) was the most studied and apparently the most promising in the evaluation of overactive bladder (OAB) and neurogenic detrusor overactivity (NDO). Urinary levels of ATP, prostaglandin E2 (PGE2), Brain-Derived Neurotrophic Factor (BDNF) and some cytokines were also significantly higher in most studies in patients with NDO or OAB. Epidermal Growth Factor (EGF), Heparin-Binding EGF (HBEGF) and Antiproliferative Factor (APF) were the most studied urinary markers in bladder pain syndrome, with a significant increase (EGF APF) or decrease (HBEGF) in cases of interstitial cystitis (compared to healthy controls). The urinary N-terminal-telopeptide (NTx) could be predictive of a failed mid-urethral sling. However, few studies reported the diagnostic values of the markers, their association with urodynamic parameters were rarely evaluated and the existence of a publication bias is likely. No randomized controlled study has so far compared the urinary markers to urodynamic evaluation. In the future, urinary markers could complete or replace urodynamic examination. However, to date, there is no high level of evidence study comparing these markers to urodynamics and their use can therefore not be recommended in daily practice. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Regio- and Enantioselective N-Allylations of Imidazole, Benzimidazole, and Purine Heterocycles Catalyzed by Single-Component Metallacyclic Iridium Complexes

PubMed Central

Stanley, Levi M.

2010-01-01

Highly regio- and enantioselective iridium-catalyzed N-allylations of benzimidazoles, imidazoles, and purines have been developed. N-Allylated benzimidazoles and imidazoles were isolated in high yields (up to 97%) with high branched-to-linear selectivity (up to 99:1) and enantioselectivity (up to 98% ee) from the reactions of benzimidazole and imidazole nucleophiles with unsymmetrical allylic carbonates in the presence of single component, ethylene-bound, metallacyclic iridium catalysts. N-Allylated purines were also obtained in high yields (up to 91%) with high N9:N7 selectivity (up to 96:4), high branched-to-linear selectivity (98:2), and high enantioselectivity (up to 98% ee) under similar conditions. The reactions encompass a range of benzimidazole, imidazole, and purine nucleophiles, as well as a variety of unsymmetrical aryl, heteroaryl, and aliphatic allylic carbonates. Competition experiments between common amine nucleophiles and the heterocyclic nitrogen nucleophiles studied in this work illustrate the effect of nucleophile pKa on the rate of iridium-catalyzed N-allylation reactions. Kinetic studies on the allylation of benzimidazole catalyzed by metallacyclic iridium-phosphoramidite complexes, in combination with studies on the deactivation of these catalysts in the presence of heterocyclic nucleophiles, provide insight into the effects of the structure of the phosphoramidite ligands on the stability of the metallacyclic catalysts. The data obtained from these studies has led to the development of N-allylations of benzimidazoles and imidazoles in the absence of an exogenous base. PMID:19480431

Pyrimidine Biosynthesis in Lactobacillus leichmannii

PubMed Central

Hutson, Judith Y.; Downing, Mancourt

1968-01-01

Tracer studies of pyrimidine biosynthesis in Lactobacillus leichmannii (ATCC 7830) indicated that, while aspartate is utilized in the usual manner, the guanido carbon of arginine, rather than carbon dioxide, is utilized as a pyrimidine precursor. The guanido carbon of arginine also contributes, to some extent, to the carbon dioxide pool utilized for purine biosynthesis. The enzyme of the first reaction leading from arginine to pyrimidines, arginine deiminase, was investigated in crude bacterial extracts. It was inhibited by thymidylic acid and purine ribonucleotides, and to a lesser extent by purine deoxynucleotides and deoxycytidylic acid. Under the assay conditions employed, a number of nucleotides had no effect on the enzyme activity of the aspartate transcarbamylase of L. leichmannii. Growth of the cells in media containing uracil, compared to growth in media without uracil, resulted in a four- to fivefold decrease in the concentrations of aspartate transcar-bamylase and dihydroorotase and a twofold increase in the concentration of arginine deiminase, as estimated from specific enzyme activity in crude extracts of the cells. A small increase in specific enzyme activity of ornithine transcarbamylase and carbamate kinase was also observed in extracts obtained from cells grown on uracil. No appreciable change in concentration of any of the five enzymes studied was detected when the cells were grown in media containing thymidine or guanylic acid. A hypothetical scheme which suggests a relationship between the control of purine and pyrimidine biosynthesis in this bacterium and which is consistent with the experimental results obtained is presented. PMID:5686000

Convergence of inhibitory neural inputs regulate motor activity in the murine and monkey stomach

PubMed Central

Shaylor, Lara A.; Hwang, Sung Jin; Sanders, Kenton M.

2016-01-01

Inhibitory motor neurons regulate several gastric motility patterns including receptive relaxation, gastric peristaltic motor patterns, and pyloric sphincter opening. Nitric oxide (NO) and purines have been identified as likely candidates that mediate inhibitory neural responses. However, the contribution from each neurotransmitter has received little attention in the distal stomach. The aims of this study were to identify the roles played by NO and purines in inhibitory motor responses in the antrums of mice and monkeys. By using wild-type mice and mutants with genetically deleted neural nitric oxide synthase (Nos1−/−) and P2Y1 receptors (P2ry1−/−) we examined the roles of NO and purines in postjunctional inhibitory responses in the distal stomach and compared these responses to those in primate stomach. Activation of inhibitory motor nerves using electrical field stimulation (EFS) produced frequency-dependent inhibitory junction potentials (IJPs) that produced muscle relaxations in both species. Stimulation of inhibitory nerves during slow waves terminated pacemaker events and associated contractions. In Nos1−/− mice IJPs and relaxations persisted whereas in P2ry1−/− mice IJPs were absent but relaxations persisted. In the gastric antrum of the non-human primate model Macaca fascicularis, similar NO and purine neural components contributed to inhibition of gastric motor activity. These data support a role of convergent inhibitory neural responses in the regulation of gastric motor activity across diverse species. PMID:27634009

Convergence of inhibitory neural inputs regulate motor activity in the murine and monkey stomach.

PubMed

Shaylor, Lara A; Hwang, Sung Jin; Sanders, Kenton M; Ward, Sean M

2016-11-01

Inhibitory motor neurons regulate several gastric motility patterns including receptive relaxation, gastric peristaltic motor patterns, and pyloric sphincter opening. Nitric oxide (NO) and purines have been identified as likely candidates that mediate inhibitory neural responses. However, the contribution from each neurotransmitter has received little attention in the distal stomach. The aims of this study were to identify the roles played by NO and purines in inhibitory motor responses in the antrums of mice and monkeys. By using wild-type mice and mutants with genetically deleted neural nitric oxide synthase (Nos1 -/- ) and P2Y1 receptors (P2ry1 -/- ) we examined the roles of NO and purines in postjunctional inhibitory responses in the distal stomach and compared these responses to those in primate stomach. Activation of inhibitory motor nerves using electrical field stimulation (EFS) produced frequency-dependent inhibitory junction potentials (IJPs) that produced muscle relaxations in both species. Stimulation of inhibitory nerves during slow waves terminated pacemaker events and associated contractions. In Nos1 -/- mice IJPs and relaxations persisted whereas in P2ry1 -/- mice IJPs were absent but relaxations persisted. In the gastric antrum of the non-human primate model Macaca fascicularis, similar NO and purine neural components contributed to inhibition of gastric motor activity. These data support a role of convergent inhibitory neural responses in the regulation of gastric motor activity across diverse species. Copyright © 2016 the American Physiological Society.

Spectral investigations and DFT studies of 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione (caffeine) interaction and recognition by single amino acid derived self-assembled nanostructures

NASA Astrophysics Data System (ADS)

Govindhan, R.; Karthikeyan, B.

2018-03-01

Recognition of xanthine alkaloid caffeine with 3,5-bis(trifluoromethyl)benzylamine derived peptide nanotubes (BTTPNTs) through chemical interaction have been achieved through the host-guest like interaction. DFT simulation is carried out for caffeine interacted with BTTPNTs system and also experimentally characterized by ultraviolet-visible (UV-vis) absorbance, confocal Raman spectra (CRS) with microscopic imaging (CRM), FT-Raman, surface enhanced Raman scattering (SERS), UV-diffuse reflectance spectra (UV-DRS), high resolution transmission electron microscopy (HR-TEM) and cyclic voltammetry (CV) studies. The results are used to examine the morphologies, size of the nanostructure and study of its interaction with the caffeine molecule. The results show that BTTPNTs is having potential for sensing the caffeine molecules through the binding occurred from the NH2 of tyrosine moiety of the BTTPNTs. This intermolecular association through face-to-face stacking of BTTPNTs is explained by detailed DFT calculations.

Adenosine-Associated Delivery Systems

PubMed Central

Kazemzadeh-Narbat, Mehdi; Annabi, Nasim; Tamayol, Ali; Oklu, Rahmi; Ghanem, Amyl; Khademhosseini, Ali

2016-01-01

Adenosine is a naturally occurring purine nucleoside in every cell. Many critical treatments such as modulating irregular heartbeat (arrhythmias), regulation of central nervous system (CNS) activity, and inhibiting seizural episodes can be carried out using adenosine. Despite the significant potential therapeutic impact of adenosine and its derivatives, the severe side effects caused by their systemic administration have significantly limited their clinical use. In addition, due to adenosine’s extremely short half-life in human blood (less than 10 s), there is an unmet need for sustained delivery systems to enhance efficacy and reduce side effects. In this paper, various adenosine delivery techniques, including encapsulation into biodegradable polymers, cell-based delivery, implantable biomaterials, and mechanical-based delivery systems, are critically reviewed and the existing challenges are highlighted. PMID:26453156

[Effects of bemethyl, ethomersol, and yakton on the liver regeneration after partial hepatectomy].

PubMed

Gaĭvoronskaia, V V; Okovityĭ, S V; Shustov, E B; Smirnov, A V

2000-01-01

It is experimentally demonstrated for the first time that the new drugs bemithyl, etomerzol, and yakton are capable of accelerating the process of liver regeneration following partial hepatectomy. The drugs produce a hasty gain in the mass of liver, increase in the content of nucleic acids and glycogen, and improve the functional state, as manifested by a decrease in the blood bilirubin and a reduction in the hexenal sleep duration. Bemithyl, etomerzol, and yakton produce a positive effect upon the liver morphology and the intracellular regeneration process. The repair activity of the new drugs exceeds that of a combination of the well-known regeneration stimulants riboxin and potassium orotate, representing derivatives of purine and pyrimidine bases.

Copper Is a Host Effector Mobilized to Urine during Urinary Tract Infection To Impair Bacterial Colonization

PubMed Central

Hyre, Amanda N.; Kavanagh, Kylie; Kock, Nancy D.; Donati, George L.

2016-01-01

ABSTRACT Urinary tract infection (UTI) is a major global infectious disease affecting millions of people annually. Human urinary copper (Cu) content is elevated during UTI caused by uropathogenic Escherichia coli (UPEC). UPEC upregulates the expression of Cu efflux genes during clinical UTI in patients as an adaptive response to host-derived Cu. Whether Cu is mobilized to urine as a host response to UTI and its role in protection against UTI remain unresolved. To address these questions, we tested the hypothesis that Cu is a host effector mobilized to urine during UTI to limit bacterial growth. Our results reveal that Cu is mobilized to urine during UTI caused by the major uropathogens Proteus mirabilis and Klebsiella pneumoniae, in addition to UPEC, in humans. Ceruloplasmin, a Cu-containing ferroxidase, is found at higher levels in UTI urine than in healthy control urine and serves as the molecular source of urinary Cu during UTI. Our results demonstrate that ceruloplasmin decreases the bioavailability of iron in urine by a transferrin-dependent mechanism. Experimental UTI with UPEC in nonhuman primates recapitulates the increased urinary Cu content observed during clinical UTI. Furthermore, Cu-deficient mice are highly colonized by UPEC, indicating that Cu is involved in the limiting of bacterial growth within the urinary tract. Collectively, our results indicate that Cu is a host effector that is involved in protection against pathogen colonization of the urinary tract. Because urinary Cu levels are amenable to modulation, augmentation of the Cu-based host defense against UTI represents a novel approach to limiting bacterial colonization during UTI. PMID:28031261

Global metabolomics reveals potential urinary biomarkers of esophageal squamous cell carcinoma for diagnosis and staging

NASA Astrophysics Data System (ADS)

Xu, Jing; Chen, Yanhua; Zhang, Ruiping; He, Jiuming; Song, Yongmei; Wang, Jingbo; Wang, Huiqing; Wang, Luhua; Zhan, Qimin; Abliz, Zeper

2016-10-01

We performed a metabolomics study using liquid chromatography-mass spectrometry (LC-MS) combined with multivariate data analysis (MVDA) to discriminate global urine profiles in urine samples from esophageal squamous cell carcinoma (ESCC) patients and healthy controls (NC). Our work evaluated the feasibility of employing urine metabolomics for the diagnosis and staging of ESCC. The satisfactory classification between the healthy controls and ESCC patients was obtained using the MVDA model, and obvious classification of early-stage and advanced-stage patients was also observed. The results suggest that the combination of LC-MS analysis and MVDA may have potential applications for ESCC diagnosis and staging. We then conducted LC-MS/MS experiments to identify the potential biomarkers with large contributions to the discrimination. A total of 83 potential diagnostic biomarkers for ESCC were screened out, and 19 potential biomarkers were identified; the variations between the differences in staging using these potential biomarkers were further analyzed. These biomarkers may not be unique to ESCCs, but instead result from any malignant disease. To further elucidate the pathophysiology of ESCC, we studied related metabolic pathways and found that ESCC is associated with perturbations of fatty acid β-oxidation and the metabolism of amino acids, purines, and pyrimidines.

Attenuated adenylosuccinate lyase deficiency: a report of one case and a review of the literature.

PubMed

Jurecka, Agnieszka; Zikanova, Marie; Jurkiewicz, Elżbieta; Tylki-Szymańska, Anna

2014-02-01

We present a 9-year follow-up of a patient with an attenuated (type II) adenylosuccinate lyase deficiency with no obvious signs of disease progression and degradation. We also review the literature, focusing on attenuated phenotype, and we report a positive effect of a ketogenic diet on seizure control. The patient presented at the age of 5 months with a history of global developmental delay. Screening of urinary purine metabolites revealed elevation of succinyladenosine and succinylaminoimidazolecarboxamide riboside (a ratio of 2:1). Mutation analysis revealed a compound heterozygosity for missense mutations: p.R426H and p.D268H. She began to walk independently at the age of 3 years. From the age of 4 years, her communication skills improved and she presented fewer autistic features. Due to poor results in seizure control, the ketogenic diet was introduced at the age of 7 years, resulting in reduction of seizure frequency. Currently, at the age of 9 years, the girl is attending a special kindergarten and is functioning very well in her preschool group. She began to make statements that form a logical continuity and make progress in simple manual operations. The patient participates in therapies such as pet therapy, hippotherapy, speech therapy, physiotherapy, hydrotherapy, and music therapy. Georg Thieme Verlag KG Stuttgart · New York.

Chemopreventive effects of Ku-jin tea against AOM-induced precancerous colorectal lesions in rats and metabolomic analysis.

PubMed

Bi, Wu; Liu, Haibo; Shen, Jie; Zhang, Ling-Hua; Li, Pei; Peng, Bing; Cao, Li; Zhang, Pengfei; He, Chunnian; Xiao, Peigen

2017-11-21

Ku-jin tea (KJT) is a health beverage prepared from the leaves of the plant Acer tataricum subsp. ginnala that has been consumed in some regions of China for thousands of years. KJT contains high levels of anti-inflammatory and antioxidative compounds such as ginnalins, but little is known about the chemopreventive effect of KJT on colon cancer. In this study, we investigated the preventive effects of KJT on colon carcinogenesis using the azoxymethane (AOM)-induced precancerous colorectal lesion model in rats. The results showed that the number of aberrant crypts, aberrant crypt foci (ACF) and crypts/focus in rats of the KJT + AOM group were significantly decreased compared with rats of the AOM group (p < 0.01). Further exploration of the prevention mechanism of KJT by UPLC-QTOF/MS-based urinary metabolomics showed that 5 metabolic pathways were modulated, including purine metabolism and amino acid metabolism, in the group with KJT. In addition, the levels of the immunomodulatory cytokines IL-1α and IL-10 were significantly decreased, and the levels of IL-2 in the serum of AOM rats increased after KJT treatment. Our present data suggest that KJT can inhibit AOM-induced colonic ACF formation and might be a useful chemopreventive agent against colorectal carcinogenesis.

Intake of Hydrolyzed Casein is Associated with Reduced Body Fat Accretion and Enhanced Phase II Metabolism in Obesity Prone C57BL/6J Mice

PubMed Central

Clausen, Morten Rahr; Zhang, Xumin; Yde, Christian C.; Ditlev, Ditte B.; Lillefosse, Haldis H.; Madsen, Lise; Kristiansen, Karsten; Liaset, Bjørn; Bertram, Hanne C.

2015-01-01

The amount and form of dietary casein have been shown to affect energy metabolism and lipid accumulation in mice, but the underlying mechanisms are not fully understood. We investigated 48 hrs urinary metabolome, hepatic lipid composition and gene expression in male C57BL/6J mice fed Western diets with 16 or 32 energy% protein in the form of extensively hydrolyzed or intact casein. LC-MS based metabolomics revealed a very strong impact of casein form on the urinary metabolome. Evaluation of the discriminatory metabolites using tandem mass spectrometry indicated that intake of extensively hydrolyzed casein modulated Phase II metabolism associated with an elevated urinary excretion of glucuronic acid- and sulphate conjugated molecules, whereas glycine conjugated molecules were more abundant in urine from mice fed the intact casein diets. Despite the differences in the urinary metabolome, we observed no differences in hepatic expression of genes involved in Phase II metabolism, but it was observed that expression of Abcc3 encoding ATP binding cassette c3 (transporter of glucuronic acid conjugates) was increased in livers of mice fed hydrolyzed casein. As glucuronic acid is derived from glucose and sulphate is derived from cysteine, our metabolomic data provided evidence for changes in carbohydrate and amino acid metabolism and we propose that this modulation of metabolism was associated with the reduced glucose and lipid levels observed in mice fed the extensively hydrolyzed casein diets. PMID:25738501

Production and nitrogen utilization in lactating dairy cows fed ground field peas with or without ruminally protected lysine and methionine.

PubMed

Pereira, A B D; Whitehouse, N L; Aragona, K M; Schwab, C S; Reis, S F; Brito, A F

2017-08-01

Previous research has shown that cows fed ≥24% of the diet dry matter (DM) as field peas decreased milk yield as well as concentration and yield of milk protein, possibly due to reduced DM intake and limited supply of Lys and Met. Twelve multiparous and 4 primiparous lactating Holstein cows were randomly assigned to 1 of 4 diets in a replicated 4 × 4 Latin square design. The diets contained (DM basis) 34.8% corn silage, 15.2% grass-legume silage, 5.9% roasted soybean, 2.4% mineral-vitamin premix, 2.0% alfalfa pellets, and either (1) 36% ground corn, 2.4% soybean meal, and 1.3% urea (UR), (2) 29.7% ground corn, 9.8% soybean meal, 0.13% ruminally protected (RP) Lys, and 0.07% RP-Met (CSBAA), (3) 25% ground field peas, 12.3% ground corn, and 2.4% soybean meal (FP), or (4) FP supplemented with 0.15% RP-Lys and 0.05% RP-Met (FPAA). Our objective was to test the effects of FP versus UR, FPAA versus CSBAA, and FPAA versus FP on milk yield and composition, N utilization, nutrient digestibility, ruminal fermentation profile, and plasma concentration of AA. Milk yield did not differ across diets. Compared with cows fed UR, those fed FP had greater DM intake, concentration and yield of milk true protein, apparent total-tract digestibility of fiber, urinary excretion of purine derivatives, and concentrations of total volatile fatty acids in the rumen and Lys in plasma, and less milk urea N and ruminal NH 3 -N. The concentration of milk urea N, as well as the concentration and yield of milk fat increased in cows fed FPAA versus CSBAA. Moreover, cows fed FPAA had greater ruminal concentration of total volatile fatty acids, increased proportions of acetate and isobutyrate, and decreased proportions of propionate and valerate than those fed CSBAA. The plasma concentrations of His, Leu, and Phe decreased, whereas plasma Met increased and plasma Lys tended to increase in cows fed FPAA versus CSBAA. Concentration of milk true protein, but not yield, was increased in cows fed FPAA versus FP. However, cows fed FPAA showed decreased concentrations of His and Leu in plasma compared with those fed FP. Overall, compared with the CSBAA diet, feeding FPAA did not negatively affect milk yield and milk protein synthesis. Furthermore, RP-Lys and RP-Met supplementation of the FP diet did not improve milk yield or milk protein synthesis, but decreased urinary urea N excretion. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Computer-generated Model of Purine Nucleoside Phosphorylase (PNP)

NASA Technical Reports Server (NTRS)

1987-01-01

Purine Nucleoside Phosphorylase (PNP) is an important target enzyme for the design of anti-cancer and immunosuppressive drugs. Bacterial PNP, which is slightly different from the human enzyme, is used to synthesize chemotherapuautic agents. Knowledge of the three-dimensional structure of the bacterial PNP molecule is useful in efforts to engineer different types of PNP enzymes, that can be used to produce new chemotherapeutic agents. This picture shows a computer model of bacterial PNP, which looks a lot like a display of colorful ribbons. Principal Investigator was Charles Bugg.

Evaluation of Urinary Btex, Nicotine, and Cotinine as Biomarkers of Airborne Pollutants in Nonsmokers and Smokers.

PubMed

Brajenović, Nataša; Karačonji, Irena Brčić; Bulog, Aleksandar

2015-01-01

Benzene, toluene, ethylbenzene, and isomeric xylenes (BTEX) are by-products of tobacco smoke and traffic emissions. The aim of this study was to determine the contribution of cigarette smoking to urinary levels of BTEX present in humans. Nicotine and cotinine, biomarkers of exposure to tobacco smoke, as well as BTEX, were measured in urine of smokers (n = 70) and nonsmokers (n = 65) using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS). In smokers, a significant correlation was found between urinary BTEX levels and nicotine and cotinine. In addition, significant regression models with nicotine and cotinine as predictors showed that BTEX in smokers' urine was predominantly derived from exposure to tobacco smoke. In nonsmokers a weak correlation between BTEX and nicotine and cotinine was found in urine. Further, there was a lack of significant contribution of BTEX to urinary nicotine and cotinine concentrations in nonsmokers. Thus, it was presumed that vehicle exhaust was the main source of exposure to BTEX in nonsmokers.

New anthropometry-based age- and sex-specific reference values for urinary 24-hour creatinine excretion based on the adult Swiss population.

PubMed

Forni Ogna, Valentina; Ogna, Adam; Vuistiner, Philippe; Pruijm, Menno; Ponte, Belen; Ackermann, Daniel; Gabutti, Luca; Vakilzadeh, Nima; Mohaupt, Markus; Martin, Pierre-Yves; Guessous, Idris; Péchère-Bertschi, Antoinette; Paccaud, Fred; Bochud, Murielle; Burnier, Michel

2015-02-27

Urinary creatinine excretion is used as a marker of completeness of timed urine collections, which are a keystone of several metabolic evaluations in clinical investigations and epidemiological surveys. We used data from two independent Swiss cross-sectional population-based studies with standardised 24-hour urinary collection and measured anthropometric variables. Only data from adults of European descent, with estimated glomerular filtration rate (eGFR) ≥60 ml/min/1.73 m2 and reported completeness of the urinary collection were retained. A linear regression model was developed to predict centiles of the 24-hour urinary creatinine excretion in 1,137 participants from the Swiss Survey on Salt and validated in 994 participants from the Swiss Kidney Project on Genes in Hypertension. The mean urinary creatinine excretion was 193 ± 41 μmol/kg/24 hours in men and 151 ± 38 μmol/kg/24 hours in women in the Swiss Survey on Salt. The values were inversely correlated with age and body mass index (BMI). We propose a validated prediction equation for 24-hour urinary creatinine excretion in the general European population, based on readily available variables such as age, sex and BMI, and a few derived normograms to ease its clinical application. This should help healthcare providers to interpret the completeness of a 24-hour urine collection in daily clinical practice and in epidemiological population studies.

Human Metabolome-derived Cofactors Are Required for the Antibacterial Activity of Siderocalin in Urine*

PubMed Central

Shields-Cutler, Robin R.; Crowley, Jan R.; Miller, Connelly D.; Stapleton, Ann E.; Cui, Weidong; Henderson, Jeffrey P.

2016-01-01

In human urinary tract infections, host cells release the antimicrobial protein siderocalin (SCN; also known as lipocalin-2, neutrophil gelatinase-associated lipocalin, or 24p3) into the urinary tract. By binding to ferric catechol complexes, SCN can sequester iron, a growth-limiting nutrient for most bacterial pathogens. Recent evidence links the antibacterial activity of SCN in human urine to iron sequestration and metabolomic variation between individuals. To determine whether these metabolomic associations correspond to functional Fe(III)-binding SCN ligands, we devised a biophysical protein binding screen to identify SCN ligands through direct analysis of human urine. This screen revealed a series of physiologic unconjugated urinary catechols that were able to function as SCN ligands of which pyrogallol in particular was positively associated with high urinary SCN activity. In a purified, defined culture system, these physiologic SCN ligands were sufficient to activate SCN antibacterial activity against Escherichia coli. In the presence of multiple SCN ligands, native mass spectrometry demonstrated that SCN may preferentially combine different ligands to coordinate iron, suggesting that availability of specific ligand combinations affects in vivo SCN antibacterial activity. These results support a mechanistic link between the human urinary metabolome and innate immune function. PMID:27780864

Elemental analysis of urinary calculi by laser induced plasma spectroscopy.

PubMed

Fang, Xiao; Ahmad, S Rafi; Mayo, Mike; Iqbal, Syed

2005-12-01

Laser induced plasma spectroscopy (LIPS) has been applied to analyse and identify elemental constituents of urinary calculi. Measurements on seven different urinary stone samples were conducted and the concentrations of some key elemental species were estimated. The elements detected with the present system were: Calcium, Magnesium, Sodium, Samarium, Potassium and Lead. Absolute concentrations of the species were derived from pre-calibration of the system for each element. Their concentrations were found to be widely different in different samples. It was observed that the samples containing a significant amount of lead have large proportion of calcium. It has been established that LIPS would allow real time clinic measurements of elemental contents and the concentrations in the biomaterials without sample preparation. The technique has the potential for routine clinic applications in urological disorder diagnosis.

Oxalobacter formigenes–Derived Bioactive Factors Stimulate Oxalate Transport by Intestinal Epithelial Cells

PubMed Central

Arvans, Donna; Jung, Yong-Chul; Antonopoulos, Dionysios; Koval, Jason; Granja, Ignacio; Bashir, Mohamed; Karrar, Eltayeb; Roy-Chowdhury, Jayanta; Musch, Mark; Asplin, John; Chang, Eugene

2017-01-01

Hyperoxaluria is a major risk factor for kidney stones and has no specific therapy, although Oxalobacter formigenes colonization is associated with reduced stone risk. O. formigenes interacts with colonic epithelium and induces colonic oxalate secretion, thereby reducing urinary oxalate excretion, via an unknown secretagogue. The difficulties in sustaining O. formigenes colonization underscore the need to identify the derived factors inducing colonic oxalate secretion. We therefore evaluated the effects of O. formigenes culture conditioned medium (CM) on apical 14C-oxalate uptake by human intestinal Caco-2-BBE cells. Compared with control medium, O. formigenes CM significantly stimulated oxalate uptake (>2.4-fold), whereas CM from Lactobacillus acidophilus did not. Treating the O. formigenes CM with heat or pepsin completely abolished this bioactivity, and selective ultrafiltration of the CM revealed that the O. formigenes–derived factors have molecular masses of 10–30 kDa. Treatment with the protein kinase A inhibitor H89 or the anion exchange inhibitor 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid completely blocked the CM-induced oxalate transport. Knockdown of the oxalate transporter SLC26A6 also significantly restricted the induction of oxalate transport by CM. In a mouse model of primary hyperoxaluria type 1, rectal administration of O. formigenes CM significantly reduced (>32.5%) urinary oxalate excretion and stimulated (>42%) distal colonic oxalate secretion. We conclude that O. formigenes–derived bioactive factors stimulate oxalate transport in intestinal cells through mechanisms including PKA activation. The reduction in urinary oxalate excretion in hyperoxaluric mice treated with O. formigenes CM reflects the in vivo retention of biologic activity and the therapeutic potential of these factors. PMID:27738124

Development of biomonitoring equivalents for barium in urine and plasma for interpreting human biomonitoring data.

PubMed

Poddalgoda, Devika; Macey, Kristin; Assad, Henry; Krishnan, Kannan

2017-06-01

The objectives of the present work were: (1) to assemble population-level biomonitoring data to identify the concentrations of urinary and plasma barium across the general population; and (2) to derive biomonitoring equivalents (BEs) for barium in urine and plasma in order to facilitate the interpretation of barium concentrations in the biological matrices. In population level biomonitoring studies, barium has been measured in urine in the U.S. (NHANES study), but no such data on plasma barium levels were identified. The BE values for plasma and urine were derived from U.S. EPA's reference dose (RfD) of 0.2 mg/kg bw/d, based on a lower confidence limit on the benchmark dose (BMDL 05 ) of 63 mg/kg bw/d. The plasma BE (9 μg Ba/L) was derived by regression analysis of the near-steady-state plasma concentrations associated with the administered doses in animals exposed to barium chloride dihydrate in drinking water for 2-years in a NTP study. Using a human urinary excretion fraction of 0.023, a BE for urinary barium (0.19 mg/L or 0.25 mg/g creatinine) was derived for US EPA's RfD. The median and the 95 th percentile barium urine concentrations of the general population in U.S. are below the BE determined in this study, indicating that the population exposure to inorganic barium is expected to be below the exposure guidance value of 0.2 mg/kg bw/d. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Differentiating Medicated Patients Suffering from Major Depressive Disorder from Healthy Controls by Spot Urine Measurement of Monoamines and Steroid Hormones

PubMed Central

Wijaya, Chandra S.; Lee, Jovia J. Z.; Husain, Syeda F.; Ho, Cyrus S. H.; McIntyre, Roger S.; Tam, Wilson W.

2018-01-01

Introduction: Major Depressive Disorder (MDD) is a common psychiatric disorder. Currently, there is no objective, cost-effective and non-invasive method to measure biological markers related to the pathogenesis of MDD. Previous studies primarily focused on urinary metabolite markers which are not proximal to the pathogenesis of MDD. Herein, we compare urinary monoamines, steroid hormones and the derived ratios amongst MDD when compared to healthy controls. Methods: Morning urine samples of medicated patients suffering from MDD (n = 47) and healthy controls (n = 41) were collected. Enzyme-linked immunosorbent assay (ELISA) was performed to measure five biomarkers: cortisol, dopamine, noradrenaline, serotonin and sulphate derivative of dehydroepiandrosterone (DHEAS). The mean urinary levels and derived ratios of monoamines and steroid hormones were compared between patients and controls to identify potential biomarkers. The receiver operative characteristic curve (ROC) analysis was conducted to evaluate the diagnostic performance of potential biomarkers. Results: Medicated patients with MDD showed significantly higher spot urine ratio of DHEAS/serotonin (1.56 vs. 1.19, p = 0.004) and lower ratio of serotonin/dopamine (599.71 vs. 888.60, p = 0.008) than healthy controls. A spot urine serotonin/dopamine ratio cut-off of >667.38 had a sensitivity of 73.2% and specificity of 51.1%. Conclusions: Our results suggest that spot urine serotonin/dopamine ratio can be used as an objective diagnostic method for adults with MDD. PMID:29701669

Distinct Purine Distribution in Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Callahan, Michael P.; Smith, Karen E.; Cleaves, Henderson J.; Ruzicka, Josef; Stern, Jennifer C.; Glavin, Daniel P.; House, Christopher H.; Dworkin, Jason P.

2011-01-01

Carbonaceous chondrite meteorites are known to contain a diverse suite of organic compounds, many of which are essential components of biochemistry. Amino acids, which are the monomers of proteins, have been extensively studied in such meteorites (e.g. Botta and Bada 2002; Pizzarello et aI., 2006). The origin of amino acids in meteorites has been firmly established as extraterrestrial based on their detection typically as racemic mixtures of amino acids, the presence of many non-protein amino acids, and non-terrestrial values for compound-specific deuterium, carbon, and nitrogen isotopic measurements. In contrast to amino acids, nucleobases in meteorites have been far less studied. Nucleobases are substituted one-ring (pyrimidine) or two-ring (purine) nitrogen heterocyclic compounds and serve as the information carriers of nucleic acids and in numerous coenzymes. All of the purines (adenine, guanine, hypoxanthine, and xanthine) and pyrimidines (uracil) previously reported in meteorites are biologically common and could be interpreted as the result of terrestrial contamination (e.g. van del' Velden and Schwartz, 1974.) Unlike other meteoritic organics, there have been no observations of stochastic molecular diversity of purines and pyrimidines in meteorites, which has been a criterion for establishing extraterrestrial origin. Maltins et al. (2008) performed compound-specific stable carbon isotope measurements for uracil and xanthine in the Murchison meteorite. They assigned a non-terrestrial origin for these nucleobases; however, the possibility that interfering indigenous molecules (e.g. carboxylic acids) contributed to the 13C-enriched isotope values for these nucleobases cannot be completely ruled out. Thus, the origin of these meteoritic nucleobases has never been established unequivocally. Here we report on our investigation of extracts of II different carbonaceous chondrites covering various petrographic types (Cl, CM, and CR) and degrees of aqueous alteration (l, 2, and 3) and one ureilite. Analysis via liquid chromatography coupled with electrospray triple-stage mass spectrometry or orbitrap mass spectrometry employed a targeted approach for analysis focused on the five canonical RNA/DNA nucleobases as well as 14 non-canonical pyrimidines and purines, which have bcen observed under plausible prebiotic reactions.

Evaluating the Substrate Selectivity of Alkyladenine DNA Glycosylase: The Synergistic Interplay of Active Site Flexibility and Water Reorganization.

PubMed

Lenz, Stefan A P; Wetmore, Stacey D

2016-02-09

Human alkyladenine DNA glycosylase (AAG) functions as part of the base excision repair (BER) pathway by cleaving the N-glycosidic bond that connects nucleobases to the sugar-phosphate backbone in DNA. AAG targets a range of structurally diverse purine lesions using nonspecific DNA-protein π-π interactions. Nevertheless, the enzyme discriminates against the natural purines and is inhibited by pyrimidine lesions. This study uses molecular dynamics simulations and seven different neutral or charged substrates, inhibitors, or canonical purines to probe how the bound nucleotide affects the conformation of the AAG active site, and the role of active site residues in dictating substrate selectivity. The neutral substrates form a common DNA-protein hydrogen bond, which results in a consistent active site conformation that maximizes π-π interactions between the aromatic residues and the nucleobase required for catalysis. Nevertheless, subtle differences in DNA-enzyme contacts for different neutral substrates explain observed differential catalytic efficiencies. In contrast, the exocyclic amino groups of the natural purines clash with active site residues, which leads to catalytically incompetent DNA-enzyme complexes due to significant reorganization of active site water. Specifically, water resides between the A nucleobase and the active site aromatic amino acids required for catalysis, while a shift in the position of the general base (E125) repositions (potentially nucleophilic) water away from G. Despite sharing common amino groups, the methyl substituents in cationic purine lesions (3MeA and 7MeG) exhibit repulsion with active site residues, which repositions the damaged bases in the active site in a manner that promotes their excision. Overall, we provide a structural explanation for the diverse yet discriminatory substrate selectivity of AAG and rationalize key kinetic data available for the enzyme. Specifically, our results highlight the complex interplay of many different DNA-protein interactions used by AAG to facilitate BER, as well as the crucial role of the general base and water (nucleophile) positioning. The insights gained from our work will aid the understanding of the function of other enzymes that use flexible active sites to exhibit diverse substrate specificity.

Effect of training load structure on purine metabolism in middle-distance runners.

PubMed

Zieliński, Jacek; Kusy, Krzysztof; Rychlewski, Tadeusz

2011-09-01

There are no studies analyzing the effect of training loads on purine metabolism during long training periods. The study's purpose was to evaluate the effect of training load changes and subsequent detraining on purine metabolism in middle-distance runners during a 1-yr cycle. In four characteristic points of the training cycle, loads assigned to five intensity zones, pre- and postexercise plasma hypoxanthine (Hx) and uric acid, and erythrocyte Hx-guanine phosphoribosyltransferase (HGPRT) activity were determined in 11 male middle-distance runners at the national level, practicing competitive sport for 8.1 ± 0.3 yr and with a mean age of 22.3 ± 0.7 yr, body mass of 73.0 ± 3.4 kg, and body height of 180 ± 2.2 cm. In the competition phase (CP), training loads in aerobic compensation and threshold zones decreased by 65.4% and by 20.5%, respectively. At the same time, anaerobic training loads increased by 132.5% in the VO(2max) zone and by 74.6% in the lactic acid tolerance zone. Postexercise Hx decreased significantly in CP by 6.2 μmol·L(-1). and increased in the transition phase (TP) by 17.4 μmol·L(-1). Both pre- and postexercise HGPRT activity increased significantly in CP by 9.3 nmol·mg(-1)·h(-1). and by 4.9 nmol·mg(-1)·h(-1). , respectively, and decreased significantly in TP by 10.6 nmol·mg(-1)·h(-1). and by 12.0 nmol·mg(-1)·h(-1). , respectively. A significant uric acid increase of 54 μmol·L(-1). was revealed merely in TP. The effect of anaerobic training on purine metabolism is significant despite of a very short total duration of anaerobic loads. Elevated preexercise HGPRT activity in CP suggests adaptation changes consisting in a "permanent readiness" for purine salvage. The detraining in TP leads to reverse adaptation changes. Probably, plasma Hx concentration and erythrocyte HGPRT activity may be considered as a useful measure of training status.

Purine 3':5'-cyclic nucleotides with the nucleobase in a syn orientation: cAMP, cGMP and cIMP.

PubMed

Řlepokura, Katarzyna Anna

2016-06-01

Purine 3':5'-cyclic nucleotides are very well known for their role as the secondary messengers in hormone action and cellular signal transduction. Nonetheless, their solid-state conformational details still require investigation. Five crystals containing purine 3':5'-cyclic nucleotides have been obtained and structurally characterized, namely adenosine 3':5'-cyclic phosphate dihydrate, C10H12N5O6P·2H2O or cAMP·2H2O, (I), adenosine 3':5'-cyclic phosphate 0.3-hydrate, C10H12N5O6P·0.3H2O or cAMP·0.3H2O, (II), guanosine 3':5'-cyclic phosphate pentahydrate, C10H12N5O7P·5H2O or cGMP·5H2O, (III), sodium guanosine 3':5'-cyclic phosphate tetrahydrate, Na(+)·C10H11N5O7P(-)·4H2O or Na(cGMP)·4H2O, (IV), and sodium inosine 3':5'-cyclic phosphate tetrahydrate, Na(+)·C10H10N4O7P(-)·4H2O or Na(cIMP)·4H2O, (V). Most of the cyclic nucleotide zwitterions/anions [two from four cAMP present in total in (I) and (II), cGMP in (III), cGMP(-) in (IV) and cIMP(-) in (V)] are syn conformers about the N-glycosidic bond, and this nucleobase arrangement is accompanied by Crib-H...Npur hydrogen bonds (rib = ribose and pur = purine). The base orientation is tuned by the ribose pucker. An analysis of data obtained from the Cambridge Structural Database made in the context of syn-anti conformational preferences has revealed that among the syn conformers of various purine nucleotides, cyclic nucleotides and dinucleotides predominate significantly. The interactions stabilizing the syn conformation have been indicated. The inter-nucleotide contacts in (I)-(V) have been systematized in terms of the chemical groups involved. All five structures display three-dimensional hydrogen-bonded networks.

Asymmetric purine-pyrimidine distribution in cellular small RNA population of papaya

PubMed Central

2012-01-01

Background The small RNAs (sRNA) are a regulatory class of RNA mainly represented by the 21 and 24-nucleotide size classes. The cellular sRNAs are processed by RNase III family enzyme dicer (Dicer like in plant) from a self-complementary hairpin loop or other type of RNA duplexes. The papaya genome has been sequenced, but its microRNAs and other regulatory RNAs are yet to be analyzed. Results We analyzed the genomic features of the papaya sRNA population from three sRNA deep sequencing libraries made from leaves, flowers, and leaves infected with Papaya Ringspot Virus (PRSV). We also used the deep sequencing data to annotate the micro RNA (miRNA) in papaya. We identified 60 miRNAs, 24 of which were conserved in other species, and 36 of which were novel miRNAs specific to papaya. In contrast to the Chargaff’s purine-pyrimidine equilibrium, cellular sRNA was significantly biased towards a purine rich population. Of the two purine bases, higher frequency of adenine was present in 23nt or longer sRNAs, while 22nt or shorter sRNAs were over represented by guanine bases. However, this bias was not observed in the annotated miRNAs in plants. The 21nt species were expressed from fewer loci but expressed at higher levels relative to the 24nt species. The highly expressed 21nt species were clustered in a few isolated locations of the genome. The PRSV infected leaves showed higher accumulation of 21 and 22nt sRNA compared to uninfected leaves. We observed higher accumulation of miRNA* of seven annotated miRNAs in virus-infected tissue, indicating the potential function of miRNA* under stressed conditions. Conclusions We have identified 60 miRNAs in papaya. Our study revealed the asymmetric purine-pyrimidine distribution in cellular sRNA population. The 21nt species of sRNAs have higher expression levels than 24nt sRNA. The miRNA* of some miRNAs shows higher accumulation in PRSV infected tissues, suggesting that these strands are not totally functionally redundant. The findings open a new avenue for further investigation of the sRNA silencing pathway in plants. PMID:23216749

Asymmetric purine-pyrimidine distribution in cellular small RNA population of papaya.

PubMed

Aryal, Rishi; Yang, Xiaozeng; Yu, Qingyi; Sunkar, Ramanjulu; Li, Lei; Ming, Ray

2012-12-05

The small RNAs (sRNA) are a regulatory class of RNA mainly represented by the 21 and 24-nucleotide size classes. The cellular sRNAs are processed by RNase III family enzyme dicer (Dicer like in plant) from a self-complementary hairpin loop or other type of RNA duplexes. The papaya genome has been sequenced, but its microRNAs and other regulatory RNAs are yet to be analyzed. We analyzed the genomic features of the papaya sRNA population from three sRNA deep sequencing libraries made from leaves, flowers, and leaves infected with Papaya Ringspot Virus (PRSV). We also used the deep sequencing data to annotate the micro RNA (miRNA) in papaya. We identified 60 miRNAs, 24 of which were conserved in other species, and 36 of which were novel miRNAs specific to papaya. In contrast to the Chargaff's purine-pyrimidine equilibrium, cellular sRNA was significantly biased towards a purine rich population. Of the two purine bases, higher frequency of adenine was present in 23nt or longer sRNAs, while 22nt or shorter sRNAs were over represented by guanine bases. However, this bias was not observed in the annotated miRNAs in plants. The 21nt species were expressed from fewer loci but expressed at higher levels relative to the 24nt species. The highly expressed 21nt species were clustered in a few isolated locations of the genome. The PRSV infected leaves showed higher accumulation of 21 and 22nt sRNA compared to uninfected leaves. We observed higher accumulation of miRNA* of seven annotated miRNAs in virus-infected tissue, indicating the potential function of miRNA* under stressed conditions. We have identified 60 miRNAs in papaya. Our study revealed the asymmetric purine-pyrimidine distribution in cellular sRNA population. The 21nt species of sRNAs have higher expression levels than 24nt sRNA. The miRNA* of some miRNAs shows higher accumulation in PRSV infected tissues, suggesting that these strands are not totally functionally redundant. The findings open a new avenue for further investigation of the sRNA silencing pathway in plants.

Purines in the eye: recent evidence for the physiological and pathological role of purines in the RPE, retinal neurons, astrocytes, Müller cells, lens, trabecular meshwork, cornea and lacrimal gland

PubMed Central

Sanderson, Julie; Dartt, Darlene A.; Trinkaus-Randall, Vickery; Pintor, Jesus; Civan, Mortimer M.; Delamere, Nicholas A.; Fletcher, Erica L.; Salt, Thomas E.; Grosche, Antje; Mitchell, Claire H.

2014-01-01

This review highlights recent findings that describe how purines modulate the physiological and pathophysiological responses of ocular tissues. For example, in lacrimal glands the cross-talk between P2X7 receptors and both M3 muscarinic receptors and α1D-adrenergic receptors can influence tear secretion. In the cornea, purines lead to post-translational modification of EGFR and structural proteins that participate in wound repair in the epithelium and influence the expression of matrix proteins in the stroma. Purines act at receptors on both the trabecular meshwork and ciliary epithelium to modulate intraocular pressure (IOP); ATP-release pathways of inflow and outflow cells differ, possibly permitting differential modulation of adenosine delivery. Modulators of trabecular meshwork cell ATP release include cell volume, stretch, extracellular Ca2+ concentration, oxidation state, actin remodeling and possibly endogenous cardiotonic steroids. In the lens, osmotic stress leads to ATP release following TRPV4 activation upstream of hemichannel opening. In the anterior eye, diadenosine polyphosphates such as Ap4A act at P2 receptors to modulate the rate and composition of tear secretion, impact corneal wound healing and lower IOP. The Gq11-coupled P2Y1-receptor contributes to volume control in Müller cells and thus the retina. P2X receptors are expressed in neurons in the inner and outer retina and contribute to visual processing as well as the demise of retinal ganglion cells. In RPE cells, the balance between extracellular ATP and adenosine may modulate lysosomal pH and the rate of lipofuscin formation. In optic nerve head astrocytes, mechanosensitive ATP release via pannexin hemichannels, coupled with stretch-dependent upregulation of pannexins, provides a mechanism for ATP signaling in chronic glaucoma. With so many receptors linked to divergent functions throughout the eye, ensuring the transmitters remain local and stimulation is restricted to the intended target may be a key issue in understanding how physiological signaling becomes pathological in ocular disease. PMID:25151301

The gas–liquid chromatography of carboxylic acid esters of the urinary 11-deoxy-17-oxo steroids

PubMed Central

Sadler, Patricia A.; Kellie, A. E.

1967-01-01

1. The gas–liquid-chromatographic separations of the acetate, propionate, n-butyrate, isobutyrate and n-valerate esters of androsterone, aetiocholanolone and dehydroepiandrosterone were studied on a 1% neopentyl glycol sebacate column. The n-butyrate, isobutyrate and n-valerate esters were well resolved. 2. The three steroids derived from hydrolysed urinary 17-oxo steroid conjugate extracts were analysed by gas–liquid chromatography after conversion into their n-butyrate esters. The results were compared with independent determinations involving chromatography on alumina. PMID:4227802

The gas-liquid chromatography of carboxylic acid esters of the urinary 11-deoxy-17-oxo steroids. Determination as n-butyrates.

PubMed

Sadler, P A; Kellie, A E

1967-06-01

1. The gas-liquid-chromatographic separations of the acetate, propionate, n-butyrate, isobutyrate and n-valerate esters of androsterone, aetiocholanolone and dehydroepiandrosterone were studied on a 1% neopentyl glycol sebacate column. The n-butyrate, isobutyrate and n-valerate esters were well resolved. 2. The three steroids derived from hydrolysed urinary 17-oxo steroid conjugate extracts were analysed by gas-liquid chromatography after conversion into their n-butyrate esters. The results were compared with independent determinations involving chromatography on alumina.

Investigation of the microstructure and mineralogical composition of urinary calculi fragments by synchrotron radiation X-ray microtomography: a feasibility study.

PubMed

Kaiser, Jozef; Holá, Markéta; Galiová, Michaela; Novotný, Karel; Kanický, Viktor; Martinec, Petr; Sčučka, Jiří; Brun, Francesco; Sodini, Nicola; Tromba, Giuliana; Mancini, Lucia; Kořistková, Tamara

2011-08-01

The outcomes from the feasibility study on utilization of synchrotron radiation X-ray microtomography (SR-μCT) to investigate the texture and the quantitative mineralogical composition of selected calcium oxalate-based urinary calculi fragments are presented. The comparison of the results obtained by SR-μCT analysis with those derived from current standard analytical approaches is provided. SR-μCT is proved as a potential effective technique for determination of texture, 3D microstructure, and composition of kidney stones.

Metabolomics analysis of rice responses to salinity stress revealed elevation of serotonin, and gentisic acid levels in leaves of tolerant varieties.

PubMed

Gupta, Poulami; De, Bratati

2017-07-03

A GC-MS based analytical approach was undertaken to understand the metabolomic responses of seedlings of 2 salt sensitive (Sujala and MTU 7029) and 2 tolerant varieties (Bhutnath, and Nonabokra) of indica rice (Oryza sativa L.) to NaCl induced stress. The 4 varieties responded differently to NaCl treatment with respect to the conserved primary metabolites (sugars, polyols, amino acids, organic acids and certain purine derivatives) of the leaf of rice seedlings. However, there were significant differences in salt induced production of chorismic acid derivatives. Serotonin level was increased in both the salt tolerant varieties in response to NaCl induced stress. In both the salt tolerant varieties, increased production of the signaling molecule gentisic acid in response to NaCl treatment was noticed. Salt tolerant varieties also produced increased level of ferulic acid and vanillic acid. In the salt sensitive varieties, cinnamic acid derivatives, 4-hydroxycinnamic acid (in Sujala) and 4-hydroxybenzoic acid (in MTU 7029), were elevated in the leaves. So increased production of the 2 signaling molecules serotonin and gentisic acid may be considered as 2 important biomarker compounds produced in tolerant varieties contributing toward NaCl tolerance.

Reaction of. beta. -propiolactone with derivatives of adenine and with DNA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, R.; Mieyal, J.J.; Goldthwait, D.A.

1982-01-01

The reaction of deoxyadenosine with ..beta..-propiolactone produces two derivatives. One is 1-(2-carboxyethyl)-2-deoxyadenosine (CEdA). The proposed structure for the other is 3-(..beta..-D-2-deoxyribosyl)-7,8-dihydropyrimido-(2,l-i)purine-9-one (dDPP). Spectral characteristics of both compounds are presented. These include u.v. spectra of each in acidic, neutral and alkaline solutions, i.r. spectra, fluorescence spectra, and n.m.r. spectra. The dDPP can be converted to CEdA by mild acid hydrolysis, and the CEdA can be converted to dDPP by reaction with a carbodiimide derivative. When poly A was reacted with ..beta..-propiolactone, the yield of dDPP in the polymer was 7-9%. When double-stranded DNA was alkylated by (/sup 3/H)..beta..-propiolactone at relatively highmore » concentrations and then acid hydrolyzed to separate 1-(2-carboxyethyl)adenine (CEA) and 7-(2-carboxyethyl)guanine (CEG), and CEA to CEG ratio of up to 0.62 was obtained. With relatively low concentrations of (/sup 3/H)..beta..-propiolactone, the yield of CEA was low with double-stranded DNA but was 5-6 fold greater with single-stranded DNA.« less

Enantiomeric and Isotopic Analysis of Sugar Derivatives in Carbonaceous Meteorites

NASA Technical Reports Server (NTRS)

Cooper, George; Asiyo, Cynthia; Turk, Kendra; DeVincenzi, Donald (Technical Monitor)

2002-01-01

Several classes of organic compounds are found in carbonaceous meteorites including amino acids, carboxylic acids, hydroxy acids, purines, and pyrimidines. Such compounds are thought to have been delivered to the early Earth in asteroids and comets and may have played a role in the origin of life. Likewise, sugar derivatives are critical to all known lifeforms. Recent analyses of the Murchison and Murray carbonaceous meteorites revealed a diverse suite of such derivatives, i.e., sugar alcohols, and sugar acids. This presentation will focus primarily on the analysis of individual sugar acids - their enantiomeric and isotopic composition. Analysis of these compounds may reveal the nature of past (or present) meteoritic sugars themselves. For example, if parent sugars decomposed (by well-known mechanisms) to give the present acids, were their enantiomeric ratios preserved? Combined with other evidence, the enantiomeric composition of such compounds as glyceric acid and (especially) rare acids may help to answer such questions. C-13 and D isotope analysis of meteoritic sugar alcohols (glycerol, threitol, ribitol, etc.) as a group revealed that they were indigenous to the meteorite. Preliminary C-13 analysis of glyceric acid shows that it is also extraterrestrial.

Fast and automated functional classification with MED-SuMo: an application on purine-binding proteins.

PubMed

Doppelt-Azeroual, Olivia; Delfaud, François; Moriaud, Fabrice; de Brevern, Alexandre G

2010-04-01

Ligand-protein interactions are essential for biological processes, and precise characterization of protein binding sites is crucial to understand protein functions. MED-SuMo is a powerful technology to localize similar local regions on protein surfaces. Its heuristic is based on a 3D representation of macromolecules using specific surface chemical features associating chemical characteristics with geometrical properties. MED-SMA is an automated and fast method to classify binding sites. It is based on MED-SuMo technology, which builds a similarity graph, and it uses the Markov Clustering algorithm. Purine binding sites are well studied as drug targets. Here, purine binding sites of the Protein DataBank (PDB) are classified. Proteins potentially inhibited or activated through the same mechanism are gathered. Results are analyzed according to PROSITE annotations and to carefully refined functional annotations extracted from the PDB. As expected, binding sites associated with related mechanisms are gathered, for example, the Small GTPases. Nevertheless, protein kinases from different Kinome families are also found together, for example, Aurora-A and CDK2 proteins which are inhibited by the same drugs. Representative examples of different clusters are presented. The effectiveness of the MED-SMA approach is demonstrated as it gathers binding sites of proteins with similar structure-activity relationships. Moreover, an efficient new protocol associates structures absent of cocrystallized ligands to the purine clusters enabling those structures to be associated with a specific binding mechanism. Applications of this classification by binding mode similarity include target-based drug design and prediction of cross-reactivity and therefore potential toxic side effects.

Astrocyte dysfunction following molybdenum-associated purine loading could initiate Parkinson's disease with dementia.

PubMed

Bourke, Christopher A

2018-01-01

Sporadic or idiopathic Parkinson's disease is a movement disorder with a worldwide distribution, a long pre-clinical latent period and a frequent association with dementia. The combination of molybdenum deficiency and purine ingestion could explain the movement disorder, the distribution, the latent period and the dementia association. Recent studies in sheep have shown that molybdenum deficiency enables some dietary purines to accumulate in the central nervous system. This causes astrocyte dysfunction, altered neuromodulation and eventually irreversible central nervous system disease. Humans and sheep share the ability to salvage purines and this ability places humans at risk when they ingest xanthosine, inosine, adenosine and guanosine. Adenosine ingestion in molybdenum-deficient humans will lead to adenosine loading and potentially a disturbance to the A2a adenosine receptors in the nigro-striatum. This could result in Parkinson's disease. Guanosine ingestion in molybdenum-deficient humans will lead to guanosine loading and potentially a disturbance to the guanosine receptors in the hippocampus, amygdala and ventral striatum. This could result in dementia. The molybdenum content of the average daily diet in the United States is 0.07 ppm and in the United Kingdom 0.04 ppm. Central nervous system disease occurs in sheep at <0.04 ppm. Consistent with the role proposed for molybdenum deficiency in Parkinson's disease is the observation that affected individuals have elevated sulfur amino acid levels, depressed sulfate levels, and depressed uric acid levels. Likewise the geographical distribution of Parkinson's dementia complex on Guam corresponds with the distribution of molybdenum-deficient soils hence molybdenum-deficient food gardens on that island.

Complex-formation between reduced xanthine oxidase and purine substrates demonstrated by electron paramagnetic resonance

PubMed Central

Pick, Frances M.; Bray, R. C.

1969-01-01

The origin of the Rapid molybdenum electron-paramagnetic-resonance signals, which are obtained on reducing xanthine oxidase with purine or with xanthine, and whose parameters were measured by Bray & Vänngård (1969), was studied. It is concluded that these signals represent complexes of reduced enzyme with substrate molecules. Xanthine forms one complex at high concentrations and a different one at low concentrations. Purine forms a complex indistinguishable from the low-concentration xanthine complex. There are indications that some other substrates also form complexes, but uric acid, a reaction product, does not appear to do so. The possible significance of the complexes in the catalytic cycle of the enzyme is discussed and it is suggested that they represent substrate molecules bound at the reduced active site, waiting their turn to react there, when the enzyme has been reoxidized. Support for this role for the complexes was deduced from experiments in which frozen samples of enzyme–xanthine mixtures, prepared by the rapid-freezing method, were warmed until the signals began to change. Under these conditions an increase in amplitude of the Very Rapid signal took place. Data bearing on the origin of the Slow molybdenum signal are also discussed. This signal disappears only slowly in the presence of oxygen, and its appearance rate is unaffected by change in the concentration of dithionite. It is concluded that, like other signals from the enzyme, it is due to Mov but that a slow change of ligand takes place before it is seen. The Slow species, like the Rapid, seems capable of forming complexes with purines. PMID:4310056

Immunoconjugates in the management of hairy cell leukemia

PubMed Central

Kreitman, Robert J.; Pastan, Ira

2015-01-01

Hairy cell leukemia (HCL) is an indolent B-cell malignancy effectively treated but not often cured by purine analog therapy; after multiple courses of purine analogs, patients can become purine analog resistant and in need of alternative therapies. Complete remission to single-agent purine analog is often accompanied by minimal residual disease (MRD), residual HCL cells detectable by immunologic methods, considered a risk factor for eventual relapse. Several different non-chemotherapy approaches are being used to target relapsed and refractory HCL, including inhibitors of BRAF, but so far only monoclonal antibody (MAb)-based approaches have been reported to eliminate MRD in a high percentage of patients. One of the MAb-based options for HCL currently under clinical investigation involves recombinant immunotoxins, containing a fragment of a MAb and a bacterial toxin. The bacterial toxin, a highly potent fragment from Pseudomonas exotoxin, catalytically ADP-ribosylates elongation factor 2 (EF2), resulting in protein synthesis inhibition and apoptotic cell death. Recombinant immunotoxins tested in HCL patients include LMB-2, targeting CD25, and BL22, targeting CD22. An affinity matured version of BL22, termed moxetumomab pasudotox (formerly HA22 or CAT-8015) achieved high CR rates in phase I, and is currently undergoing multicenter Phase 3 testing. Phase I testing was without dose-limiting toxicity, although 2 patients had grade 2 hemolytic uremic syndrome (HUS) with transient grade 1 abnormalities in platelets and creatinine. Preclinical work is underway to identify residues on moxetumomab pasudotox leading to immunogenicity. Moxetumomab pasudotox is undergoing pivotal testing for relapsed and refractory HCL. PMID:26614902

Pharmacometabolomic Signature of Ataxia SCA1 Mouse Model and Lithium Effects

PubMed Central

Wikoff, William R.; Gatchel, Jennifer R.; Wang, Lu; Barupal, Dinesh K.; Crespo-Barreto, Juan; Fiehn, Oliver

2013-01-01

We have shown that lithium treatment improves motor coordination in a spinocerebellar ataxia type 1 (SCA1) disease mouse model (Sca1154Q/+). To learn more about disease pathogenesis and molecular contributions to the neuroprotective effects of lithium, we investigated metabolomic profiles of cerebellar tissue and plasma from SCA1-model treated and untreated mice. Metabolomic analyses of wild-type and Sca1154Q/+ mice, with and without lithium treatment, were performed using gas chromatography time-of-flight mass spectrometry and BinBase mass spectral annotations. We detected 416 metabolites, of which 130 were identified. We observed specific metabolic perturbations in Sca1154Q/+ mice and major effects of lithium on metabolism, centrally and peripherally. Compared to wild-type, Sca1154Q/+ cerebella metabolic profile revealed changes in glucose, lipids, and metabolites of the tricarboxylic acid cycle and purines. Fewer metabolic differences were noted in Sca1154Q/+ mouse plasma versus wild-type. In both genotypes, the major lithium responses in cerebellum involved energy metabolism, purines, unsaturated free fatty acids, and aromatic and sulphur-containing amino acids. The largest metabolic difference with lithium was a 10-fold increase in ascorbate levels in wild-type cerebella (p<0.002), with lower threonate levels, a major ascorbate catabolite. In contrast, Sca1154Q/+ mice that received lithium showed no elevated cerebellar ascorbate levels. Our data emphasize that lithium regulates a variety of metabolic pathways, including purine, oxidative stress and energy production pathways. The purine metabolite level, reduced in the Sca1154Q/+ mice and restored upon lithium treatment, might relate to lithium neuroprotective properties. PMID:23936457

Rapid noninvasive detection of experimental atherosclerotic lesions with novel 99mTc-labeled diadenosine tetraphosphates

PubMed Central

Elmaleh, David R.; Narula, Jagat; Babich, John W.; Petrov, Artiom; Fischman, Alan J.; Khaw, Ban-An; Rapaport, Eliezer; Zamecnik, Paul C.

1998-01-01

The development of a noninvasive imaging procedure for identifying atherosclerotic lesions is extremely important for the clinical management of patients with coronary artery and peripheral vascular disease. Although numerous radiopharmaceuticals have been proposed for this purpose, none has demonstrated the diagnostic accuracy required to replace invasive angiography. In this report, we used the radiolabeled purine analog, 99mTc diadenosine tetraphosphate (Ap4A; AppppA, P1,P4-di(adenosine-5′)-tetraphosphate) and its analogue 99mTc AppCHClppA for imaging experimental atherosclerotic lesions in New Zealand White rabbits. Serial gamma camera images were obtained after intravenous injection of the radiolabeled dinucleotides. After acquiring the final images, the animals were sacrificed, ex vivo images of the aortas were recorded, and biodistribution was measured. 99mTc-Ap4A and 99mTc AppCHClppA accumulated rapidly in atherosclerotic abdominal aorta, and lesions were clearly visible within 30 min after injection in all animals that were studied. Both radiopharmaceuticals were retained in the lesions for 3 hr, and the peak lesion to normal vessel ratio was 7.4 to 1. Neither of the purine analogs showed significant accumulation in the abdominal aorta of normal (control) rabbits. The excised aortas showed lesion patterns that were highly correlated with the in vivo and ex vivo imaging results. The present study demonstrates that purine receptors are up-regulated in experimental atherosclerotic lesions and 99mTc-labeled purine analogs have potential for rapid noninvasive detection of plaque formation. PMID:9435254

Antinociceptive effects of intracerebroventricular administration of guanine-based purines in mice: evidences for the mechanism of action.

PubMed

Schmidt, André P; Böhmer, Ana Elisa; Leke, Renata; Schallenberger, Cristhine; Antunes, Catiele; Pereira, Mery Stéfani L; Wofchuk, Susana T; Elisabetsky, Elaine; Souza, Diogo O

2008-10-09

It is well known that adenine-based purines exert multiple effects on pain transmission. However, less attention has been given to the potential effects of guanine-based purines (GBPs) on pain transmission. The aim of this study was to investigate the effects of intracerebroventricular (i.c.v.) guanosine and GMP on mice pain models. Mice received an i.c.v. injection of vehicle (saline or 10 muM NaOH), guanosine (5 to 400 nmol), or GMP (240 to 960 nmol). Additional groups were also pre-treated with i.c.v. injection of the A(1)/A(2A) antagonist caffeine (15 nmol), the non-selective opioid antagonist naloxone (12.5 nmol), or the 5'-nucleotidase inhibitor AOPCP (1 nmol). Measurements of CSF purine levels and cortical glutamate uptake were performed after treatments. Guanosine and GMP produced dose-dependent antinociceptive effects. Neither caffeine nor naloxone affected guanosine antinociception. Pre-treatment with AOPCP completely prevented GMP antinociception, indicating that conversion of GMP to guanosine is required for its antinociceptive effects. Intracerebroventricular administration of guanosine and GMP induced, respectively, a 180- and 1800-fold increase on CSF guanosine levels. Guanosine was able to prevent the decrease on cortical glutamate uptake induced by intraplantar capsaicin. This study provides new evidence on the mechanism of action of GBPs, with guanosine and GMP presenting antinociceptive effects in mice. This effect seems to be independent of adenosine and opioid receptors; it is, however, at least partially associated with modulation of the glutamatergic system by guanosine.

Fast and automated functional classification with MED-SuMo: An application on purine-binding proteins

PubMed Central

Doppelt-Azeroual, Olivia; Delfaud, François; Moriaud, Fabrice; de Brevern, Alexandre G

2010-01-01

Ligand–protein interactions are essential for biological processes, and precise characterization of protein binding sites is crucial to understand protein functions. MED-SuMo is a powerful technology to localize similar local regions on protein surfaces. Its heuristic is based on a 3D representation of macromolecules using specific surface chemical features associating chemical characteristics with geometrical properties. MED-SMA is an automated and fast method to classify binding sites. It is based on MED-SuMo technology, which builds a similarity graph, and it uses the Markov Clustering algorithm. Purine binding sites are well studied as drug targets. Here, purine binding sites of the Protein DataBank (PDB) are classified. Proteins potentially inhibited or activated through the same mechanism are gathered. Results are analyzed according to PROSITE annotations and to carefully refined functional annotations extracted from the PDB. As expected, binding sites associated with related mechanisms are gathered, for example, the Small GTPases. Nevertheless, protein kinases from different Kinome families are also found together, for example, Aurora-A and CDK2 proteins which are inhibited by the same drugs. Representative examples of different clusters are presented. The effectiveness of the MED-SMA approach is demonstrated as it gathers binding sites of proteins with similar structure-activity relationships. Moreover, an efficient new protocol associates structures absent of cocrystallized ligands to the purine clusters enabling those structures to be associated with a specific binding mechanism. Applications of this classification by binding mode similarity include target-based drug design and prediction of cross-reactivity and therefore potential toxic side effects. PMID:20162627

The Formation of Nucleobases from the Irradiation of Purine in Astophysical Ices and Comparisons with Meteorites.

NASA Technical Reports Server (NTRS)

Sandford, S. A.; Materese, C. K.; Nuevo, M.

2016-01-01

N-heterocycles have been identified in meteorites and their extraterrestrial origins are suggested by isotopic ratio measurements. Although small N- heterocycles have not been detected in the interstellar medium (ISM), recent experiments in our lab have shown that the irradiation of the aromatic molecules like benzene (C6H6) and naphthalene (C10H8) in mixed molecular ices leads to the formation of O- and N-heterocyclic molecules. Among the class of N-heterocycles are the nucleobases, which are of astrobiological interest because they are the information bearing units of DNA and RNA. Nucleobases have been detected in meteorites [3-5], with isotopic signatures that are also consistent with an extraterrestrial origin. Three of the biologically relevant nucleobases (uracil, cytosine, and guanine) have a pyrimidine core structure while the remaining two (adenine and guanine) possess a purine core. Previous experiments in our lab have demonstrated that all of the bio-logical nucleobases (and numerous other molecules) with a pyrimidine core structure can be produced by irradiating pyrimidine in mixed molecular ices of several compositions [6-8]. In this work, we study the formation of purine-based molecules, including the nucleobases adenine, and guanine, from the ultraviolet (UV) irradiation of purine in ices consisting mixtures of H2O and NH3 at low temperature. The experiments are designed to simulate the astrophysical conditions under which these species may be formed in dense molecular clouds, protoplanetary disks, or on the surfaces of icy bodies in planetary systems.

Metabolomics analysis: Finding out metabolic building blocks

PubMed Central

2017-01-01

In this paper we propose a new methodology for the analysis of metabolic networks. We use the notion of strongly connected components of a graph, called in this context metabolic building blocks. Every strongly connected component is contracted to a single node in such a way that the resulting graph is a directed acyclic graph, called a metabolic DAG, with a considerably reduced number of nodes. The property of being a directed acyclic graph brings out a background graph topology that reveals the connectivity of the metabolic network, as well as bridges, isolated nodes and cut nodes. Altogether, it becomes a key information for the discovery of functional metabolic relations. Our methodology has been applied to the glycolysis and the purine metabolic pathways for all organisms in the KEGG database, although it is general enough to work on any database. As expected, using the metabolic DAGs formalism, a considerable reduction on the size of the metabolic networks has been obtained, specially in the case of the purine pathway due to its relative larger size. As a proof of concept, from the information captured by a metabolic DAG and its corresponding metabolic building blocks, we obtain the core of the glycolysis pathway and the core of the purine metabolism pathway and detect some essential metabolic building blocks that reveal the key reactions in both pathways. Finally, the application of our methodology to the glycolysis pathway and the purine metabolism pathway reproduce the tree of life for the whole set of the organisms represented in the KEGG database which supports the utility of this research. PMID:28493998

Urinary Podocyte Microparticles Identify Prealbuminuric Diabetic Glomerular Injury

PubMed Central

Burger, Dylan; Thibodeau, Jean-Francois; Holterman, Chet E.; Burns, Kevin D.; Touyz, Rhian M.

2014-01-01

Microparticles (MPs) are small (0.1–1.0 µm) vesicles shed from the surface of cells in response to stress. Whether podocytes produce MPs and whether this production reflects glomerular injury are unclear. We examined MP formation in cultured human podocytes (hPODs) and diabetic mice. hPODs were exposed to cyclical stretch, high glucose (HG; 25 mM), angiotensin II, or TGF-β. Urinary podocyte MPs were assessed in three mouse models of diabetic nephropathy: streptozotocin (STZ)-treated, OVE26, and Akita mice. Cyclic stretch and HG increased MP release as assessed by flow cytometry (P<0.01 and P<0.05, respectively, versus controls). Inhibition of Rho-kinase (ROCK) with fasudil blocked HG-induced podocyte MP formation. STZ-treated (8 weeks) mice exhibited increased urinary podocyte MPs compared with age-matched nondiabetic mice. Similarly, 16-week-old OVE26 mice had elevated levels of urinary podocyte MPs compared with wild-type littermates (P<0.01). In 1 week post-STZ–treated and 6- and 12-week-old Akita mice, urinary podocyte MPs increased significantly compared with those MPs in nondiabetic mice, despite normal urinary albumin levels. Our results indicate that podocytes produce MPs that are released into urine. Podocyte-derived MPs are generated by exposure to mechanical stretch and high glucose in vitro and could represent early markers of glomerular injury in diabetic nephropathy. PMID:24676640

Copper Is a Host Effector Mobilized to Urine during Urinary Tract Infection To Impair Bacterial Colonization.

PubMed

Hyre, Amanda N; Kavanagh, Kylie; Kock, Nancy D; Donati, George L; Subashchandrabose, Sargurunathan

2017-03-01

Urinary tract infection (UTI) is a major global infectious disease affecting millions of people annually. Human urinary copper (Cu) content is elevated during UTI caused by uropathogenic Escherichia coli (UPEC). UPEC upregulates the expression of Cu efflux genes during clinical UTI in patients as an adaptive response to host-derived Cu. Whether Cu is mobilized to urine as a host response to UTI and its role in protection against UTI remain unresolved. To address these questions, we tested the hypothesis that Cu is a host effector mobilized to urine during UTI to limit bacterial growth. Our results reveal that Cu is mobilized to urine during UTI caused by the major uropathogens Proteus mirabilis and Klebsiella pneumoniae , in addition to UPEC, in humans. Ceruloplasmin, a Cu-containing ferroxidase, is found at higher levels in UTI urine than in healthy control urine and serves as the molecular source of urinary Cu during UTI. Our results demonstrate that ceruloplasmin decreases the bioavailability of iron in urine by a transferrin-dependent mechanism. Experimental UTI with UPEC in nonhuman primates recapitulates the increased urinary Cu content observed during clinical UTI. Furthermore, Cu-deficient mice are highly colonized by UPEC, indicating that Cu is involved in the limiting of bacterial growth within the urinary tract. Collectively, our results indicate that Cu is a host effector that is involved in protection against pathogen colonization of the urinary tract. Because urinary Cu levels are amenable to modulation, augmentation of the Cu-based host defense against UTI represents a novel approach to limiting bacterial colonization during UTI. Copyright © 2017 American Society for Microbiology.

Neurochemical Measurement of Adenosine in Discrete Brain Regions of Five Strains of Inbred Mice

PubMed Central

Pani, Amar K.; Jiao, Yun; Sample, Kenneth J.; Smeyne, Richard J.

2014-01-01

Adenosine (ADO), a non-classical neurotransmitter and neuromodulator, and its metabolites adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP), have been shown to play an important role in a number of biochemical processes. Although their signaling is well described, it has been difficult to directly, accurately and simultaneously quantitate these purines in tissue or fluids. Here, we describe a novel method for measuring adenosine (ADO) and its metabolites using high performance liquid chromatography with electrochemical detection (HPLC-ECD). Using this chromatographic technique, we examined baseline levels of ADO and ATP, ADP and AMP in 6 different brain regions of the C57BL/6J mouse: stratum, cortex, hippocampus, olfactory bulb, substantia nigra and cerebellum and compared ADO levels in 5 different strains of mice (C57BL/6J, Swiss-Webster, FVB/NJ, 129P/J, and BALB/c). These studies demonstrate that baseline levels of purines vary significantly among the brain regions as well as between different mouse strains. These dissimilarities in purine concentrations may explain the variable phenotypes among background strains described in neurological disease models. PMID:24642754

Binding of nickel /II/ to 5-prime-nucleoside monophosphates and related compounds. [role in origin of life

NASA Technical Reports Server (NTRS)

Orenberg, J. B.; Kjos, K. M.; Winkler, R.; Link, J.; Lawless, J. G.

1982-01-01

The interactions of Ni(II) cation with a representative suite of purine bases and the respective nucleosides and nucleotides have been studied by ultraviolet difference spectroscopy. Apparent association constants were determined for each system at pH 7.0, using computer linear regression coupled with an iteration technique. The specificity of binding of Ni(2+) for the purine nucleotides studied at pH 7.0 was 5-prime-GMP greater than 5-prime-AMP; a similar ordering was also found for the respective nucleosides and bases. In this study binding was not observed for the suite of pyramidines used, although an Ni(2+) -cytidine complex has been observed (Fiskin and Beer, 1965). It was also found that Ni(2+) bound more strongly to the purine 5-prime-nucleotides than to the respective nucleosides and bases. These trends are explained in terms of metal-ligand bonds and available bonding positions on the ligands. A role for metal-ion-nucleotide types of complexes is suggested in the processes that might have given rise to the origin of life.

Ni2+-binding RNA motifs with an asymmetric purine-rich internal loop and a G-A base pair.

PubMed Central

Hofmann, H P; Limmer, S; Hornung, V; Sprinzl, M

1997-01-01

RNA molecules with high affinity for immobilized Ni2+ were isolated from an RNA pool with 50 randomized positions by in vitro selection-amplification. The selected RNAs preferentially bind Ni2+ and Co2+ over other cations from first series transition metals. Conserved structure motifs, comprising about 15 nt, were identified that are likely to represent the Ni2+ binding sites. Two conserved motifs contain an asymmetric purine-rich internal loop and probably a mismatch G-A base pair. The structure of one of these motifs was studied with proton NMR spectroscopy and formation of the G-A pair at the junction of helix and internal loop was demonstrated. Using Ni2+ as a paramagnetic probe, a divalent metal ion binding site near this G-A base pair was identified. Ni2+ ions bound to this motif exert a specific stabilization effect. We propose that small asymmetric purine-rich loops that contain a G-A interaction may represent a divalent metal ion binding site in RNA. PMID:9409620

Pathways of nitrogen assimilation in cowpea nodules studied using /sup 15/N/sub 2/ and allopurinol. [Vigna unguiculata L. Walp. cv Vita

DOE Office of Scientific and Technical Information (OSTI.GOV)

Atkins, C.A.; Storer, P.J.; Pate, J.S.

1988-01-01

In the presence of 0.5 millimolar allopurinol (4-hydroxypyrazolo (3,4-d)pyrimidine), an inhibitor of NAD:xanthine oxidoreductase (EC 1.2.3.2), intact attached nodules of cowpea (vigna unguiculata L. Walp. cv Vita 3) formed (/sup 15/N)xanthine from /sup 15/N/sub 2/ at rates equivalent to those of ureide synthesis, confirming the direct assimilation of fixed nitrogen into purines. Xanthine accumulated in nodules and was exported in increasing amounts in xylem of allopurinol-treated plants. Other intermediates of purine oxidation, de novo purine synthesis, and ammonia assimilation did not increase and, over the time course of experiments (4 hours), allopurinol had no effect on nitrogenase (EC 1.87.99.2) activity.more » Negligible /sup 15/N -labeling of asparagine from /sup 15/N/sub 2/ was observed, suggesting that the significant pool (up to 14 micromoles per gram of nodule fresh weight) of this amide in cowpea nodules was not formed directly from fixation but may have accumulated as a consequence of phloem delivery.« less

The biochemical origins of the surface-enhanced Raman spectra of bacteria: a metabolomics profiling by SERS.

PubMed

Premasiri, W Ranjith; Lee, Jean C; Sauer-Budge, Alexis; Théberge, Roger; Costello, Catherine E; Ziegler, Lawrence D

2016-07-01

The dominant molecular species contributing to the surface-enhanced Raman spectroscopy (SERS) spectra of bacteria excited at 785 nm are the metabolites of purine degradation: adenine, hypoxanthine, xanthine, guanine, uric acid, and adenosine monophosphate. These molecules result from the starvation response of the bacterial cells in pure water washes following enrichment from nutrient-rich environments. Vibrational shifts due to isotopic labeling, bacterial SERS spectral fitting, SERS and mass spectrometry analysis of bacterial supernatant, SERS spectra of defined bacterial mutants, and the enzymatic substrate dependence of SERS spectra are used to identify these molecular components. The absence or presence of different degradation/salvage enzymes in the known purine metabolism pathways of these organisms plays a central role in determining the bacterial specificity of these purine-base SERS signatures. These results provide the biochemical basis for the development of SERS as a rapid bacterial diagnostic and illustrate how SERS can be applied more generally for metabolic profiling as a probe of cellular activity. Graphical Abstract Bacterial typing by metabolites released under stress.

The Formation of Nucleobases from the UV Irradiation of Astrophysical Ice Analogs

NASA Technical Reports Server (NTRS)

Materese, C. K.; Nuevo, M.; Sandford, S. A.

2017-01-01

Nucleobases are the fundamental information bearing components of both RNA and DNA. They are central to all known terrestrial life and they are generally conserved between species. Biological nucleobases can be divided into two groups based on the N-heterocyclic molecules pyrimidine (uracil, cytosine, and thymine) and purine (adenine and guanine) respectively. Do date, no experimental conditions have been determined that could produce both pyrimidines and purines together, abiotically, in a ter-restrial environment or an early terrestrial analog. Organic materials produced in extraterrestrial envi-ronments may have been delivered to the primitive earth by comets and meteorites and may have contrib-uted to the emergence of life. To date, some, but not all nucleobases have been detected in meteorites and their isotopic signatures may be consistent with an extraterrestrial origin. Earlier work in our lab demonstrated that it is possible to produce all of the pyrimidine group nucleobases from the UV-irradiation of pyrimidine in astrophysically relevant ice analogs. Here we report our most recent work, which studied the formation of the purine group nucleobases under similar conditions.

[DNA tandem lesion: 5',8-cyclo-2'-deoxyadenosine. The influence on human health].

PubMed

Merecz, A; Karwowski, B T

2016-01-01

Nucleic acids are the targets for various endogenous and exogenous genotoxic agents, including reactive oxygen species. The appearance of a hydroxyl racial (^(.)OH), the most harmful molecule, next to an oligonucleotide can lead to two types of DNA damage: strand breaks or nucleobase modifications. Since clustered DNA damage is defined as the presence of two or more lesions in one helix turn, purine 5',8-cyclo-2'-deoxynucleosides are recognized as tandem lesions: both sugar moieties and base have been modified within one nucleoside/nucleotide. The hydrogen abstraction from the C5' group of nucleosides/nucleotides by ^(.)OH, with subsequent C8 C5' cyclisation results in purine 5',8-cyclonucleoside formation. Due to its unusual 3D structure and the fact that only one radical hit is needed for purine 5',8-cyclonucleoside formation their influence on genome stability/integrity and DNA repair processes are subjects of medical interest. In the present work the influence of 5',8-cyclo-2'-deoxyadenosine on DNA spatial geometry and DNA repair hinder in connection with human health, such as neurological disorders is discussed.

Quantum chemical study of leaving group activation in T. vivax nucleoside hydrolase

NASA Astrophysics Data System (ADS)

Loverix, Stefan; Versees, Wim; Steyaert, Jan; Geerlings, Paul

General acid catalysis is a powerful and widely used strategy in enzymatic nucleophilic displacement reactions. However, in the nucleoside hydrolase of the parasite Trypanosoma vivax, crystallographic and mutagenesis studies failed to identify a general acid. The only groups in the vicinity of the leaving group that contribute to catalysis are (i) the indole side chain of Trp260, and (ii) the 5'-group of the substrate's ribose moiety. The x-ray structure of the slow Asp10Ala mutant of nucleoside hydrolase with the substrate inosine bound in the active site displays a face-to-face aromatic stacking interaction between Trp260 and the purine base of the substrate, as well as a peculiar C4'-endo ribose pucker that allows the 5'-OH group to accept an intramolecular hydrogen bond from the C8 of the purine. The first interaction (aromatic stacking) has been shown to raise the pKa of the leaving purine. Here, we present a DFT study showing that the 5'-OH group of ribose fulfills a similar role, rather than stabilizing the oxocarbenium-like transition state.

NCI-H295R, a human adrenal cortex-derived cell line, expresses purinergic receptors linked to Ca²⁺-mobilization/influx and cortisol secretion.

PubMed

Nishi, Haruhisa; Arai, Hirokazu; Momiyama, Toshihiko

2013-01-01

Purinergic receptor expression and involvement in steroidogenesis were examined in NCI-H295R (H295R), a human adrenal cortex cell line which expresses all the key enzymes necessary for steroidogenesis. mRNA/protein for multiple P1 (A(2A) and A(2B)), P2X (P2X₅ and P2X₇), and P2Y (P2Y₁, P2Y₂, P2Y₆, P2Y₁₂, P2Y₁₃, and P2Y₁₄) purinergic receptors were detected in H295R. 2MeS-ATP (10-1000 µM), a P2Y₁ agonist, induced glucocorticoid (GC) secretion in a dose-dependent manner, while other extracellular purine/pyrimidine agonists (1-1000 µM) had no distinct effect on GC secretion. Extracellular purines, even non-steroidogenic ones, induced Ca²⁺-mobilization in the cells, independently of the extracellular Ca²⁺ concentration. Increases in intracellular Ca²⁺ concentration induced by extracellular purine agonists were transient, except when induced by ATP or 2MeS-ATP. Angiotensin II (AngII: 100 nM) and dibutyryl-cyclic AMP (db-cAMP: 500 µM) induced both GC secretion and Ca²⁺-mobilization in the presence of extracellular Ca²⁺ (1.2 mM). GC secretion by AngII was reduced by nifedipine (10-100 µM); whereas the Ca²⁺ channel blocker did not inhibit GC secretion by 2MeS-ATP. Thapsigargin followed by extracellular Ca²⁺ exposure induced Ca²⁺-influx in H295R, and the cells expressed mRNA/protein of the component molecules for store-operated calcium entry (SOCE): transient receptor C (TRPC) channels, calcium release-activated calcium channel protein 1 (Orai-1), and the stromal interaction molecule 1 (STIM1). In P2Y₁-knockdown, 2MeS-ATP-induced GC secretion was significantly inhibited. These results suggest that H295R expresses a functional P2Y₁ purinergic receptor for intracellular Ca²⁺-mobilization, and that P2Y₁ is linked to SOCE-activation, leading to Ca²⁺-influx which might be necessary for glucocorticoid secretion.

Effects of dietary crude protein and rumen-degradable protein concentrations on urea recycling, nitrogen balance, omasal nutrient flow, and milk production in dairy cows.

PubMed

Mutsvangwa, T; Davies, K L; McKinnon, J J; Christensen, D A

2016-08-01

The objective of this study was to determine how interactions between dietary crude protein (CP) and rumen-degradable protein (RDP) concentrations alter urea-nitrogen recycling, nitrogen (N) balance, omasal nutrient flow, and milk production in lactating Holstein cows. Eight multiparous Holstein cows (711±21kg of body weight; 91±17d in milk at the start of the experiment) were used in a replicated 4×4 Latin square design with a 2×2 factorial arrangement of dietary treatments and 29-d experimental periods. Four cows in one Latin square were fitted with ruminal cannulas to allow ruminal and omasal sampling. The dietary treatment factors were CP (14.9 vs. 17.5%; dry matter basis) and RDP (63 vs. 69% of CP) contents. Dietary RDP concentration was manipulated by including unprocessed or micronized canola meal. Diet adaptation (d 1-20) was followed by 8d (d 21-29) of sample and data collection. Continuous intrajugular infusions of [(15)N(15)N]-urea (220mg/d) were conducted for 4d (d 25-29) with concurrent total collections of urine and feces to estimate N balance and whole-body urea kinetics. Proportions of [(15)N(15)N]- and [(14)N(15)N]-urea in urinary urea, and (15)N enrichment in feces were used to calculate urea kinetics. For the low-CP diets, cows fed the high-RDP diet had a greater DM intake compared with those fed the low-RDP diet, but the opposite trend was observed for cows fed the high-CP diets. Dietary treatment had no effect on milk yield. Milk composition and milk component yields were largely unaffected by dietary treatment; however, on the low-CP diets, milk fat yield was greater for cows fed the low-RDP diet compared with those fed the high-RDP diet, but it was unaffected by RDP concentration on the high-CP diets. On the high-CP diets, milk urea nitrogen concentration was greater in cows fed the high-RDP diet compared with those fed the low-RDP diet, but it was unaffected by RDP concentration on the low-CP diets. Ruminal NH3-N concentration tended to be greater in cows fed the high-CP diet compared with those fed the low-CP diet, and it was greater in cows fed the high-RDP diet as compared with those fed the low-RDP diet. Nitrogen intake and both total N and urea-N excretion in urine were greater for cows fed the high-CP diet compared with those fed the low-CP diet. However, N balance and urinary excretion of purine derivatives were unaffected by dietary treatment. Urea-N entry rate (UER) was greater in cows fed the high-CP diet compared with those fed the low-CP diet; however, UER was unaffected by dietary RDP concentration. The proportion of urea-N recycled to the gastrointestinal tract (as a percentage of UER) was greater in cows fed the low-CP diet compared with those fed the high-CP diet. In summary, reducing dietary CP concentration decreased urinary N excretion but had no effect on milk yield, thus resulting in an overall improvement in milk N efficiency. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Phenolic Amides Are Potent Inhibitors of De Novo Nucleotide Biosynthesis.

PubMed

Pisithkul, Tippapha; Jacobson, Tyler B; O'Brien, Thomas J; Stevenson, David M; Amador-Noguez, Daniel

2015-09-01

An outstanding challenge toward efficient production of biofuels and value-added chemicals from plant biomass is the impact that lignocellulose-derived inhibitors have on microbial fermentations. Elucidating the mechanisms that underlie their toxicity is critical for developing strategies to overcome them. Here, using Escherichia coli as a model system, we investigated the metabolic effects and toxicity mechanisms of feruloyl amide and coumaroyl amide, the predominant phenolic compounds in ammonia-pretreated biomass hydrolysates. Using metabolomics, isotope tracers, and biochemical assays, we showed that these two phenolic amides act as potent and fast-acting inhibitors of purine and pyrimidine biosynthetic pathways. Feruloyl or coumaroyl amide exposure leads to (i) a rapid buildup of 5-phosphoribosyl-1-pyrophosphate (PRPP), a key precursor in nucleotide biosynthesis, (ii) a rapid decrease in the levels of pyrimidine biosynthetic intermediates, and (iii) a long-term generalized decrease in nucleotide and deoxynucleotide levels. Tracer experiments using (13)C-labeled sugars and [(15)N]ammonia demonstrated that carbon and nitrogen fluxes into nucleotides and deoxynucleotides are inhibited by these phenolic amides. We found that these effects are mediated via direct inhibition of glutamine amidotransferases that participate in nucleotide biosynthetic pathways. In particular, feruloyl amide is a competitive inhibitor of glutamine PRPP amidotransferase (PurF), which catalyzes the first committed step in de novo purine biosynthesis. Finally, external nucleoside supplementation prevents phenolic amide-mediated growth inhibition by allowing nucleotide biosynthesis via salvage pathways. The results presented here will help in the development of strategies to overcome toxicity of phenolic compounds and facilitate engineering of more efficient microbial producers of biofuels and chemicals. Copyright © 2015, Pisithkul et al.

Phenolic Amides Are Potent Inhibitors of De Novo Nucleotide Biosynthesis

PubMed Central

Pisithkul, Tippapha; Jacobson, Tyler B.; O'Brien, Thomas J.; Stevenson, David M.

2015-01-01

An outstanding challenge toward efficient production of biofuels and value-added chemicals from plant biomass is the impact that lignocellulose-derived inhibitors have on microbial fermentations. Elucidating the mechanisms that underlie their toxicity is critical for developing strategies to overcome them. Here, using Escherichia coli as a model system, we investigated the metabolic effects and toxicity mechanisms of feruloyl amide and coumaroyl amide, the predominant phenolic compounds in ammonia-pretreated biomass hydrolysates. Using metabolomics, isotope tracers, and biochemical assays, we showed that these two phenolic amides act as potent and fast-acting inhibitors of purine and pyrimidine biosynthetic pathways. Feruloyl or coumaroyl amide exposure leads to (i) a rapid buildup of 5-phosphoribosyl-1-pyrophosphate (PRPP), a key precursor in nucleotide biosynthesis, (ii) a rapid decrease in the levels of pyrimidine biosynthetic intermediates, and (iii) a long-term generalized decrease in nucleotide and deoxynucleotide levels. Tracer experiments using 13C-labeled sugars and [15N]ammonia demonstrated that carbon and nitrogen fluxes into nucleotides and deoxynucleotides are inhibited by these phenolic amides. We found that these effects are mediated via direct inhibition of glutamine amidotransferases that participate in nucleotide biosynthetic pathways. In particular, feruloyl amide is a competitive inhibitor of glutamine PRPP amidotransferase (PurF), which catalyzes the first committed step in de novo purine biosynthesis. Finally, external nucleoside supplementation prevents phenolic amide-mediated growth inhibition by allowing nucleotide biosynthesis via salvage pathways. The results presented here will help in the development of strategies to overcome toxicity of phenolic compounds and facilitate engineering of more efficient microbial producers of biofuels and chemicals. PMID:26070680

Integrated whole-genome and transcriptome sequence analysis reveals the genetic characteristics of a riboflavin-overproducing Bacillus subtilis.

PubMed

Wang, Guanglu; Shi, Ting; Chen, Tao; Wang, Xiaoyue; Wang, Yongcheng; Liu, Dingyu; Guo, Jiaxin; Fu, Jing; Feng, Lili; Wang, Zhiwen; Zhao, Xueming

2018-06-02

Commercial riboflavin production with Bacillus subtilis has been developed by combining rational and classical strain development for almost two decades, but how an improved riboflavin producer can be created rationally is still not completely understood. In this study, we demonstrate the combined use of integrated genomic and transcriptomic analysis of the genetic basis for riboflavin over-production in B. subtilis. This methodology succeeded in discerning the positive mutations in the mutagenesis derived riboflavin producer B. subtilis 24/pMX45 through whole-genome sequencing and transcriptome sequencing. These included RibC (G199D), ribD + (G+39A), PurA (P242L), CcpN(A44S), YvrH (R222Q) and two nonsense mutations YhcF (R90*) and YwaA (Q68*). Reintroducing these specific mutations into the wild-type strain recovered the riboflavin overproduction phenotype and subsequent metabolic engineering greatly improved riboflavin production, achieving an up to 3.4-fold increase of the riboflavin titer over the sequenced producer. A novel mutation, YvrH (R222Q), involved in a typical two-component regulatory system deregulated the purine de novo synthesis pathway and increased the pool of intracellular purine metabolites, which in turn increased riboflavin production. Taken together, we present a case study of combining genome and transcriptome analysis to elucidate the genetic underpinnings of a complex cellular property, which enabled the transfer of beneficial mutations to engineer a reference strain into an overproducer. Copyright © 2018 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Phenolic amides are potent inhibitors of De Novo nucleotide biosynthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pisithkul, Tippapha; Jacobson, Tyler B.; O'Brien, Thomas J.

An outstanding challenge toward efficient production of biofuels and value-added chemicals from plant biomass is the impact that lignocellulose-derived inhibitors have on microbial fermentations. Elucidating the mechanisms that underlie their toxicity is critical for developing strategies to overcome them. Here, using Escherichia coli as a model system, we investigated the metabolic effects and toxicity mechanisms of feruloyl amide and coumaroyl amide, the predominant phenolic compounds in ammonia-pretreated biomass hydrolysates. Using metabolomics, isotope tracers, and biochemical assays, we showed that these two phenolic amides act as potent and fast-acting inhibitors of purine and pyrimidine biosynthetic pathways. Feruloyl or coumaroyl amide exposuremore » leads to (i) a rapid buildup of 5-phosphoribosyl-1-pyrophosphate (PRPP), a key precursor in nucleotide biosynthesis, (ii) a rapid decrease in the levels of pyrimidine biosynthetic intermediates, and (iii) a long-term generalized decrease in nucleotide and deoxynucleotide levels. Tracer experiments using 13C-labeled sugars and [ 15N]ammonia demonstrated that carbon and nitrogen fluxes into nucleotides and deoxynucleotides are inhibited by these phenolic amides. We found that these effects are mediated via direct inhibition of glutamine amidotransferases that participate in nucleotide biosynthetic pathways. In particular, feruloyl amide is a competitive inhibitor of glutamine PRPP amidotransferase (PurF), which catalyzes the first committed step in de novo purine biosynthesis. Finally, external nucleoside supplementation prevents phenolic amide-mediated growth inhibition by allowing nucleotide biosynthesis via salvage pathways. Furthermore, the results presented here will help in the development of strategies to overcome toxicity of phenolic compounds and facilitate engineering of more efficient microbial producers of biofuels and chemicals.« less

Phenolic amides are potent inhibitors of De Novo nucleotide biosynthesis

DOE PAGES

Pisithkul, Tippapha; Jacobson, Tyler B.; O'Brien, Thomas J.; ...

2015-06-12

An outstanding challenge toward efficient production of biofuels and value-added chemicals from plant biomass is the impact that lignocellulose-derived inhibitors have on microbial fermentations. Elucidating the mechanisms that underlie their toxicity is critical for developing strategies to overcome them. Here, using Escherichia coli as a model system, we investigated the metabolic effects and toxicity mechanisms of feruloyl amide and coumaroyl amide, the predominant phenolic compounds in ammonia-pretreated biomass hydrolysates. Using metabolomics, isotope tracers, and biochemical assays, we showed that these two phenolic amides act as potent and fast-acting inhibitors of purine and pyrimidine biosynthetic pathways. Feruloyl or coumaroyl amide exposuremore » leads to (i) a rapid buildup of 5-phosphoribosyl-1-pyrophosphate (PRPP), a key precursor in nucleotide biosynthesis, (ii) a rapid decrease in the levels of pyrimidine biosynthetic intermediates, and (iii) a long-term generalized decrease in nucleotide and deoxynucleotide levels. Tracer experiments using 13C-labeled sugars and [ 15N]ammonia demonstrated that carbon and nitrogen fluxes into nucleotides and deoxynucleotides are inhibited by these phenolic amides. We found that these effects are mediated via direct inhibition of glutamine amidotransferases that participate in nucleotide biosynthetic pathways. In particular, feruloyl amide is a competitive inhibitor of glutamine PRPP amidotransferase (PurF), which catalyzes the first committed step in de novo purine biosynthesis. Finally, external nucleoside supplementation prevents phenolic amide-mediated growth inhibition by allowing nucleotide biosynthesis via salvage pathways. Furthermore, the results presented here will help in the development of strategies to overcome toxicity of phenolic compounds and facilitate engineering of more efficient microbial producers of biofuels and chemicals.« less

Kinin and Purine Signaling Contributes to Neuroblastoma Metastasis.

PubMed

Ulrich, Henning; Ratajczak, Mariusz Z; Schneider, Gabriela; Adinolfi, Elena; Orioli, Elisa; Ferrazoli, Enéas G; Glaser, Talita; Corrêa-Velloso, Juliana; Martins, Poliana C M; Coutinho, Fernanda; Santos, Ana P J; Pillat, Micheli M; Sack, Ulrich; Lameu, Claudiana

2018-01-01

Bone marrow metastasis occurs in approximately 350,000 patients that annually die in the U.S. alone. In view of the importance of tumor cell migration into the bone marrow, we have here investigated effects of various concentrations of stromal cell-derived factor-1 (SDF-1), bradykinin- and ATP on bone marrow metastasis. We show for first time that bradykinin augmented chemotactic responsiveness of neuroblastoma cells to SDF-1 and ATP concentrations, encountered under physiological conditions. Bradykinin upregulated VEGF expression, increased metalloproteinase activity and induced adhesion of neuroblastoma cells. Bradykinin augmented SDF-1-induced intracellular Ca 2+ mobilization as well as resensitization and expression of ATP-sensing P2X7 receptors. Bradykinin treatment resulted in higher gene expression levels of the truncated P2X7B receptor compared to those of the P2X7A full-length isoform. Bradykinin as pro-metastatic factor induced tumor proliferation that was significantly decreased by P2X7 receptor antagonists; however, the peptide did not enhance cell death nor P2X7A receptor-related pore activity, promoting neuroblastoma growth. Furthermore, immunodeficient nude/nude mice transplanted with bradykinin-pretreated neuroblastoma cells revealed significantly higher metastasis rates compared to animals injected with untreated cells. In contrast, animals receiving Brilliant Blue G, a P2X7 receptor antagonist, did not show any specific dissemination of neuroblastoma cells to the bone marrow and liver, and metastasis rates were drastically reduced. Our data suggests correlated actions of kinins and purines in neuroblastoma dissemination, providing novel avenues for clinic research in preventing metastasis.

Purine Nucleotide Metabolism of Germinating Soybean Embryonic Axes

PubMed Central

Anderson, James D.

1979-01-01

Isolated soybean (Glycine max L. cv. Kent) embyronic axes metabolized [14C]glycine to ATP within the 1 hour of imbibition. Radioactivity was not detected in GTP until the 3rd hour. Throughout most of the first 24 hours of germination about 10 to 26 times as much label from [14C]glycine appears in ATP as GTP. About five times as much [14C]hypoxanthine and [14C]inosine was converted into GTP as into ATP in embryonic axes. Two independent pools of IMP appear to be used in purine nucleotide synthesis of soybean axes. PMID:16660656

HCN - A plausible source of purines, pyrimidines and amino acids on the primitive earth

NASA Technical Reports Server (NTRS)

Ferris, J.-P.; Joshi, P. C.; Edelson, E. H.; Lawless, J. G.

1978-01-01

Dilute (0.1 M) solutions of HCN condense to oligomers at pH 9.2, and hydrolysis of these oligomers yields 4,5-dihydroxypyrimidine, orotic acid, 5-hydroxyuracil, adenine, 4-aminoimidazole-5-carboxamide, and amino acids. It is suggested that the three main classes of nitrogen-containing biomolecules - purines, pyrimidines, and amino acids may have originated from HCN on the primitive earth. It is also suggested that the presence of orotic acid and 4-aminoimidazole-5-carboxamide might indicate that contemporary biosynthetic pathways for nucleotides evolved from the compounds released on hydrolysis of HCN oligomers.

Novel Mps1 kinase inhibitors: from purine to pyrrolopyrimidine and quinazoline leads.

PubMed

Bursavich, Matthew G; Dastrup, David; Shenderovich, Mark; Yager, Kraig M; Cimbora, Daniel M; Williams, Brandi; Kumar, D Vijay

2013-12-15

Mps1, also known as TTK, is a mitotic checkpoint protein kinase that has become a promising new target of cancer research. In an effort to improve the lead-likeness of our recent Mps1 purine lead compounds, a scaffold hopping exercise has been undertaken. Structure-based design, principles of conformational restriction, and subsequent scaffold hopping has led to novel pyrrolopyrimidine and quinazoline Mps1 inhibitors. These new single-digit nanomolar leads provide the basis for developing potent, novel Mps1 inhibitors with improved drug-like properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

Supercomputer analysis of purine and pyrimidine metabolism leading to DNA synthesis.

PubMed

Heinmets, F

1989-06-01

A model-system is established to analyze purine and pyrimidine metabolism leading to DNA synthesis. The principal aim is to explore the flow and regulation of terminal deoxynucleoside triophosphates (dNTPs) in various input and parametric conditions. A series of flow equations are established, which are subsequently converted to differential equations. These are programmed (Fortran) and analyzed on a Cray chi-MP/48 supercomputer. The pool concentrations are presented as a function of time in conditions in which various pertinent parameters of the system are modified. The system is formulated by 100 differential equations.

Assessment of urinary microparticles in normotensive patients with type 1 diabetes.

PubMed

Lytvyn, Yuliya; Xiao, Fengxia; Kennedy, Christopher R J; Perkins, Bruce A; Reich, Heather N; Scholey, James W; Cherney, David Z; Burger, Dylan

2017-03-01

Assessment of urinary extracellular vesicles including exosomes and microparticles (MPs) is an emerging approach for non-invasive detection of renal injury. We have previously reported that podocyte-derived MPs are increased in diabetic mice in advance of albuminuria. Here, we hypothesised that type 1 diabetes and acute hyperglycaemia would increase urinary podocyte MP levels in uncomplicated diabetes. In this post hoc exploratory analysis, we examined archived urine samples from normoalbuminuric patients with uncomplicated type 1 diabetes studied under clamped euglycaemia and hyperglycaemia and compared with healthy controls. Urinary vesicles were assessed by electron microscopy and nanoparticle tracking while podocyte MPs were assessed by flow cytometry. Neither vesicle size nor total number were significantly altered in type 1 diabetes or acute hyperglycaemia. By contrast, urinary podocyte MP levels were higher in type 1 diabetes (0.47 [0.00-3.42] MPs/μmol creatinine [Cr]) compared with healthy controls (0.00 [0.00-0.00] MPs/μmol Cr, p < 0.05) and increased under hyperglycaemic clamp (0.36 [0.00-4.15] MPs/μmol Cr during euglycaemia vs 2.70 [0.00-15.91] MPs/μmol Cr during hyperglycaemia, p < 0.05). Levels of urinary albumin to creatinine ratio and nephrin (surrogates of podocyte injury) were unchanged by type 1 diabetes or acute hyperglycaemia. Taken together, our data show that urinary podocyte MP levels are higher in patients with type 1 diabetes in advance of changes in other biomarkers (albuminuria, nephrin). Examination of podocyte MPs may serve as an early biomarker of glomerular injury in uncomplicated type 1 diabetes.

[Urinary L-type fatty acid binding protein (L-FABP) as a new urinary biomarker promulgated by the Ministry of Health, Labour and Welfare in Japan].

PubMed

Kamijo-Ikemori, Atsuko; Ichikawa, Daisuke; Matsui, Katsuomi; Yokoyama, Takeshi; Sugaya, Takeshi; Kimura, Kenjiro

2013-07-01

Liver-type fatty acid binding protein (L-FABP) is a 14kDa protein found in the cytoplasm of human renal proximal tubules. Fatty acids are bound with L-FABP and transported to the mitochondria or peroxisomes, where fatty acids are beta-oxidized, and this may play a role in fatty acid homeostasis. Moreover, L-FABP has high affinity and capacity to bind long-chain fatty acid oxidation products, and may be an effective endogenous antioxidant. Renal L-FABP is rarely expressed in the kidneys of rodents. In order to evaluate the pathological dynamics of renal L-FABP in kidney disease, human L-FABP chromosomal transgenic mice were generated. Various stress, such as massive proteinuria, hyperglycemia, hypertension, and toxins overloaded in the proximal tubules were revealed to up-regulate the gene expression of renal L-FABP and increase the excretion of L-FABP derived from the proximal tubules into urine. In clinical studies of chronic kidney disease (CKD), urinary L-FABP accurately reflected the degree of tubulointerstitial damage and correlated with the rate of CKD progression. Furthermore, a multicenter trial has shown that urinary L-FABP is more sensitive than urinary protein in predicting the progression of CKD. With respect to diabetic nephropathy and acute kidney disease (AKI), urinary L-FABP is an early diagnostic of kidney disease or a predictive marker for renal prognosis. After many clinical studies, urinary L-FABP was approved as a new tubular biomarker promulgated by the Ministry of Health, Labour and Welfare in Japan.

The effect of aliskiren on urinary cytokine/chemokine responses to clamped hyperglycaemia in type 1 diabetes.

PubMed

Cherney, David Z I; Reich, Heather N; Scholey, James W; Daneman, Denis; Mahmud, Farid H; Har, Ronnie L H; Sochett, Etienne B

2013-10-01

Acute clamped hyperglycaemia activates the renin-angiotensin-aldosterone system (RAAS) and increases the urinary excretion of inflammatory cytokines/chemokines in patients with uncomplicated type 1 diabetes mellitus. Our objective was to determine whether blockade of the RAAS would blunt the effect of acute hyperglycaemia on urinary cytokine/chemokine excretion, thereby giving insights into potentially protective effects of these agents prior to the onset of clinical nephropathy. Blood pressure, renal haemodynamic function (inulin and para-aminohippurate clearances) and urinary cytokines/chemokines were measured after 6 h of clamped euglycaemia (4-6 mmol/l) and hyperglycaemia (9-11 mmol/l) on two consecutive days in patients with type 1 diabetes mellitus (n = 27) without overt nephropathy. Measurements were repeated after treatment with aliskiren (300 mg daily) for 30 days. Before aliskiren, clamped hyperglycaemia increased filtration fraction (from 0.188 ± 0.007 to 0.206 ± 0.007, p = 0.003) and urinary fibroblast growth factor-2 (FGF2), IFN-α2 and macrophage-derived chemokine (MDC) (p < 0.005). After aliskiren, the filtration fraction response to hyperglycaemia was abolished, resulting in a lower filtration fraction after aliskiren under clamped hyperglycaemic conditions (p = 0.004), and none of the biomarkers increased in response to hyperglycaemia. Aliskiren therapy also reduced levels of urinary eotaxin, FGF2, IFN-α2, IL-2 and MDC during clamped hyperglycaemia (p < 0.005). The increased urinary excretion of inflammatory cytokines/chemokines in response to acute hyperglycaemia is blunted by RAAS blockade in humans with uncomplicated type 1 diabetes mellitus.

Molecular lipid species in urinary exosomes as potential prostate cancer biomarkers.

PubMed

Skotland, Tore; Ekroos, Kim; Kauhanen, Dimple; Simolin, Helena; Seierstad, Therese; Berge, Viktor; Sandvig, Kirsten; Llorente, Alicia

2017-01-01

Exosomes have recently appeared as a novel source of noninvasive cancer biomarkers, since these nanovesicles contain molecules from cancer cells and can be detected in biofluids. We have here investigated the potential use of lipids in urinary exosomes as prostate cancer biomarkers. A high-throughput mass spectrometry quantitative lipidomic analysis was performed to reveal the lipid composition of urinary exosomes in prostate cancer patients and healthy controls. Control samples were first analysed to characterise the lipidome of urinary exosomes and test the reproducibility of the method. In total, 107 lipid species were quantified in urinary exosomes. Several differences, for example, in cholesterol and phosphatidylcholine, were found between urinary exosomes and exosomes derived from cell lines, thus showing the importance of in vivo studies for biomarker analysis. The 36 most abundant lipid species in urinary exosomes were then quantified in 15 prostate cancer patients and 13 healthy controls. Interestingly, the levels of nine lipids species were found to be significantly different when the two groups were compared. The highest significance was shown for phosphatidylserine (PS) 18:1/18:1 and lactosylceramide (d18:1/16:0), the latter also showed the highest patient-to-control ratio. Furthermore, combinations of these lipid species and PS 18:0-18:2 distinguished the two groups with 93% sensitivity and 100% specificity. Finally, in agreement with the reported dysregulation of sphingolipid metabolism in cancer cells, alteration in specific sphingolipid lipid classes were observed. This study shows for the first time the potential use of exosomal lipid species in urine as prostate cancer biomarkers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Aryl Hydrocarbon Receptor Antagonists Promote the Expansion of Human Hematopoietic Stem Cells

PubMed Central

Boitano, Anthony E.; Wang, Jian; Romeo, Russell; Bouchez, Laure C.; Parker, Albert E.; Sutton, Sue E.; Walker, John R.; Flaveny, Colin A.; Perdew, Gary H.; Denison, Michael S.; Schultz, Peter G.; Cooke, Michael P.

2011-01-01

Although practiced clinically for over 40 years, the use of hematopoietic stem cell (HSC) transplants remains limited by the ability to expand these cells ex vivo. An unbiased screen with primary human HSC identified a purine derivative, StemRegenin 1 (SR1), that promotes the ex vivo expansion of CD34+ cells. Culture of HSC with SR1 led to a fifty-fold increase in cells expressing CD34, and a 17-fold increase in cells that retain the ability to engraft immunodeficient mice. Mechanistic studies show that SR1 acts by antagonizing the aryl hydrocarbon receptor (AhR). The identification of SR1 and AhR modulation as a means to induce ex vivo HSC expansion should facilitate the clinical use of HSC therapy. PMID:20688981

Energy transfer mechanisms in photobiological reactions. Final report, 1 April 1960--31 March 1979. [Photodynamic processes in selected biomolecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spikes, J.D.

1979-03-31

This project was concerned primarily with studies of the mechanisms of the sensitized photooxidation of selected biomolecules using a variety of phtosensitizers. Such reactions are often termed photodynamic processes. In particular we have carried out steady-state kinetic studies, flash photolysis and spectral studies, and product formation studies of the sensitized photooxidation of the five susceptible amino acids (cycteine, histidine, methonine, tryptophan, and tyrosine) and their derivatives, as well as purines and pyrimidines. A number of studies were also carried out on the mechanisms of the photodynamic inactivation of enzymes (trypsin, ribonuclease, lysozyme). Mechanism of photosensitization were studied using a varietymore » of sensitizers including flavins, porphyrins, and a number of synthetic dyes (substituted fluoresceins, acridines, thyazines).« less

Elevated urinary podocyte-derived extracellular microvesicles in renovascular hypertensive patients

PubMed Central

Kwon, Soon Hyo; Woollard, John R.; Saad, Ahmed; Garovic, Vesna D.; Zand, Ladan; Jordan, Kyra L.; Textor, Stephen C.

2017-01-01

ABSTRACT Background: An increased number of podocyte-derived extracellular vesicles (pEVs) may reflect podocyte injury in renal disease. Elevated glomerular pressure and other insults may injure podocytes, yet it remains unclear whether the numbers of pEVs are altered in hypertensive patients. We tested the hypothesis that urinary pEV levels would be elevated in patients with renovascular hypertension (RVH) compared with essential hypertension (EH) or healthy volunteers (HVs). Methods: We prospectively enrolled patients with EH (n = 30) or RVH (n = 31) to study renal blood flow (RBF) and cortical perfusion using multidetector computed tomography under controlled condition (regulated sodium intake and renin—angiotensin blockade). After isolation from urine samples, pEVs (nephrin and podocalyxin positive) were characterized by flow cytometry. Fourteen RVH patients were studied again 3 months after stenting or continued medical therapy. HVs (n = 15) served as controls. Results: The fraction of pEV among urinary EVs was elevated in RVH compared with HVs and EH (11.4 ± 6.4, 6.8 ± 3.4 and 6.3 ± 3.7%, respectively; P < 0.001) and remained unchanged after 3 additional months of therapy and after controlling for clinical parameters. However, eGFR- and age-adjusted pEV levels did not correlate with any clinical or renal parameters. Conclusions: In hypertensive patients under controlled conditions, urinary pEV levels are elevated in patients with RVH and low eGFR compared with patients with EH and relatively preserved renal function. These pEVs may reflect podocyte injury secondary to kidney damage, and their levels might represent a novel therapeutic target. PMID:27190371

Hormonal changes during 17 days of head-down bed-rest

NASA Technical Reports Server (NTRS)

Custaud, Marc-Antoine; Arnaud, Sara B.; Monk, Timothy H.; Claustrat, Bruno; Gharib, Claude; Gauquelin-Koch, Guillemette

2003-01-01

We investigated in six men the impact of 17 days of head-down bed rest (HDBR) on the daily rhythms of the hormones involved in hydroelectrolytic regulation. This HDBR study was designed to mimic a real space flight. Urine samples were collected at each voiding before, during and after HDBR. Urinary excretion of Growth Hormone (GH), Cortisol, 6 Sulfatoxymelatonin, Normetadrenaline (NMN) and Metadrenaline (NM) was determined. A decrease in urinary cortisol excretion during the night of HDBR was noted. For GH, a rhythm was found before and during HDBR. The rhythm of melatonin, evaluated with the urine excretion of 6 Sulfatoxymelatonin (aMT6S), the main hepatic metabolite, persisted throughout the experiment without any modification to the level of phase. A decrease during the night was noted for normetadrenaline urinary derivates, but only during the HDBR.

Expression and Significance of the HIP/PAP and RegIIIγ Antimicrobial Peptides during Mammalian Urinary Tract Infection.

PubMed

Spencer, John David; Jackson, Ashley R; Li, Birong; Ching, Christina B; Vonau, Martin; Easterling, Robert S; Schwaderer, Andrew L; McHugh, Kirk M; Becknell, Brian

2015-01-01

Recent evidence indicates that antimicrobial peptides (AMPs) serve key roles in defending the urinary tract against invading uropathogens. To date, the individual contribution of AMPs to urinary tract host defense is not well defined. In this study, we identified Regenerating islet-derived 3 gamma (RegIIIγ) as the most transcriptionally up-regulated AMP in murine bladder transcriptomes following uropathogenic Escherichia coli (UPEC) infection. We confirmed induction of RegIIIγ mRNA during cystitis and pyelonephritis by quantitative RT-PCR. Immunoblotting demonstrates increased bladder and urinary RegIIIγ protein levels following UPEC infection. Immunostaining localizes RegIIIγ protein to urothelial cells of infected bladders and kidneys. Human patients with UTI have increased urine concentrations of the orthologous Hepatocarcinoma-Intestine-Pancreas / Pancreatitis Associated Protein (HIP/PAP) compared to healthy controls. Recombinant RegIIIγ protein does not demonstrate bactericidal activity toward UPEC in vitro, but does kill Staphylococcus saprophyticus in a dose-dependent manner. Kidney and bladder tissue from RegIIIγ knockout mice and wild-type mice contain comparable bacterial burden following UPEC and Gram-positive UTI. Our results demonstrate that RegIIIγ and HIP/PAP expression is induced during human and murine UTI. However, their specific function in the urinary tract remains uncertain.

Expression and Significance of the HIP/PAP and RegIIIγ Antimicrobial Peptides during Mammalian Urinary Tract Infection

PubMed Central

Spencer, John David; Jackson, Ashley R.; Li, Birong; Ching, Christina B.; Vonau, Martin; Easterling, Robert S.; Schwaderer, Andrew L.; McHugh, Kirk M.; Becknell, Brian

2015-01-01

Recent evidence indicates that antimicrobial peptides (AMPs) serve key roles in defending the urinary tract against invading uropathogens. To date, the individual contribution of AMPs to urinary tract host defense is not well defined. In this study, we identified Regenerating islet-derived 3 gamma (RegIIIγ) as the most transcriptionally up-regulated AMP in murine bladder transcriptomes following uropathogenic Escherichia coli (UPEC) infection. We confirmed induction of RegIIIγ mRNA during cystitis and pyelonephritis by quantitative RT-PCR. Immunoblotting demonstrates increased bladder and urinary RegIIIγ protein levels following UPEC infection. Immunostaining localizes RegIIIγ protein to urothelial cells of infected bladders and kidneys. Human patients with UTI have increased urine concentrations of the orthologous Hepatocarcinoma-Intestine-Pancreas / Pancreatitis Associated Protein (HIP/PAP) compared to healthy controls. Recombinant RegIIIγ protein does not demonstrate bactericidal activity toward UPEC in vitro, but does kill Staphylococcus saprophyticus in a dose-dependent manner. Kidney and bladder tissue from RegIIIγ knockout mice and wild-type mice contain comparable bacterial burden following UPEC and Gram-positive UTI. Our results demonstrate that RegIIIγ and HIP/PAP expression is induced during human and murine UTI. However, their specific function in the urinary tract remains uncertain. PMID:26658437

Antibiotic Resistance of Bacteria Involved in Urinary Infections in Brazil: A Cross-Sectional and Retrospective Study

PubMed Central

Rodrigues, Wellington Francisco; Miguel, Camila Botelho; Nogueira, Ana Paula Oliveira; Ueira-Vieira, Carlos; Paulino, Tony De Paiva; Soares, Siomar De Castro; De Resende, Elisabete Aparecida Mantovani Rodrigues; Lazo-Chica, Javier Emilio; Araújo, Marcelo Costa; Oliveira, Carlo José

2016-01-01

Empirical and prolonged antimicrobial treatment of urinary tract infections caused by Escherichia coli is associated with the emergence of bacterial resistance, and not all countries have strict policies against the indiscriminate use of drugs in order to prevent resistance. This cross-sectional and retrospective study (2010–2015) aimed to evaluate the sensitivity and resistance of patient-derived E. coli to different drugs broadly used to treat urinary infections in Brazil: ampicillin + sulbactam, cephalothin, ciprofloxacin, norfloxacin, and nitrofurantoin. We obtained 1654 E. coli samples from ambulatory patients with disease symptoms of the urinary tract from a Brazilian public hospital. While all antibiotics were effective in killing E. coli to a large degree, nitrofurantoin was the most effective, with fewer samples exhibiting antibiotic resistance. We assessed the costs of generic and brand name versions of each antibiotic. Nitrofurantoin, the most effective antibiotic, was the cheapest, followed by the fluoroquinolones (ciprofloxacin and norfloxacin), ampicillin + sulbactam and, lastly, cephalothin. Finally, assessment of antibiotic resistance to fluoroquinolones over the study period and extrapolation of the data led to the conclusion that these antibiotics could no longer be effective against E. coli-based urinary infections in approximately 20 years if their indiscriminate use in empirical treatment continues. PMID:27649224

Contribution of condensed tannins and mimosine to the methane mitigation caused by feeding Leucaena leucocephala.

PubMed

Soltan, Yosra A; Morsy, Amr S; Sallam, Sobhy M A; Lucas, Ronaldo C; Louvandini, Helder; Kreuzer, Michael; Abdalla, Adibe L

2013-06-01

Leucaena (Leucaena leucocephala), a leguminous shrub promising to cope with feed scarcity in the tropics, may help in mitigating ruminal methane (CH4) emission in the tropics as well. Two experiments were conducted to evaluate the effect of Leucaena and major secondary compounds of this plant in ruminants. At first, effects of Leucaena tannins and mimosine on ruminal CH4 and nutrient degradability were tested in vitro. Incubations were made with Leucaena without or with polyethylene glycol (PEG) to exclude the tannins effects, as well as with Bermuda grass (Tifton) and lucerne hays, both either untreated or supplemented with mimosine at the same concentration that has been provided by the tested Leucaena (6.52 mg/g DM). Furthermore, in an in vivo experiment a control diet (per kg DM 700 g Tifton hay) and Leucaena diets (per kg DM 350 g Tifton hay and 350 g Leucaena), either with or without 20 g PEG/d per head, were evaluated in six Santa Inês sheep following a double Latin square design. In vitro, Leucaena resulted in the lowest (p < 0.05) gas and CH4 production and the highest (p < 0.05) partitioning factor, a measure for microbial efficiency, whereas the amount of truly degraded organic matter (TDOM) was lowest (p < 0.05) with Tifton among the experimental forage plants. Mimosine addition to lucerne and Tifton as well as PEG addition to Leucaena had no effect on ruminal CH4 and TDOM. In vivo Leucaena, compared to the Tifton diet, enhanced (p < 0.05) intake, faecal nitrogen excretion, body nitrogen retention and the excretion of urinary purine derivatives as an indicator for microbial protein synthesis and availability. This was independent of PEG addition. Leucaena also decreased (p < 0.001) CH4 emission per unit of digested organic matter by 14.1% and 10.8%, without and with PEG, respectively. No significant diet differences were observed in total-tract nutrient digestibility. The study demonstrated efficiency of Leucaena to mitigate in vivo methane emission of sheep, but did not reveal which constituent of Leucaena was primarily responsible for that since no clear efficiency of either tannins or mimosine could be demonstrated.

Effect of feeding complete feed block containing rumen protected protein, non-protein nitrogen and rumen protected fat on improving body condition and carcass traits of cull ewes.

PubMed

Bhatt, R S; Sahoo, A

2017-12-01

Nutrient utilization, body condition and carcass traits of cull ewes were studied in three dietary regimens based on complete feed block (CFB) feeding to control (C) with rumen protected protein (RPP), CU [RPP + urea (6 g/kg)] and CUF [RPP + urea + rumen protected fat (RPF; 40 g/kg)]. The RPP component (g/kg) in C had 1% formaldehyde-treated soy flakes 50, mustard cake 50 and sesame cake 30. The mustard and sesame cakes were replaced with urea on equivalent N basis in CU and CUF. The ewes were offered ad libitum CFB composed (g/kg) of concentrate 650, roughage 300 and molasses 50. The digestibility of OM and EE was higher (p < 0.05) in CUF than in CU and C, while that of NDF and ADF was lower (p < 0.05). The CP digestibility was higher in both CU and CUF. Utilization of N and Ca was higher (p < 0.05) in CUF compared with C and CU. Urinary purine derivatives analysis and microbial N synthesis were similar in all the groups. Blood glucose concentration improved at 90 day compared with 0 day. Ruminal attributes showed a higher (p < 0.05) pH, total N, TCA precipitable N, entodiniomorphs and total ciliate population in CU and CUF than in the control. The CUF had higher (p < 0.01) DM, digestible OM and ME intake, which resulted in higher (p < 0.05) weight gain and better feed efficiency. Ewes in all the groups showed an improvement in carcass traits at 90 day. The pre-slaughter weight was higher (p < 0.05) and dissected and KOH bone content was lower in CUF. Thus, feeding of CFB with urea as a cheaper N source and RPF to enrich with energy supported the improved performance as evidenced from higher nutrient input, 'utilization and efficiency with enhanced carcass traits' for better marketability and returns from cull ewes. Journal of Animal Physiology and Animal Nutrition © 2017 Blackwell Verlag GmbH.

Extracellular guanosine and GTP promote expression of differentiation markers and induce S-phase cell-cycle arrest in human SH-SY5Y neuroblastoma cells.

PubMed

Guarnieri, S; Pilla, R; Morabito, C; Sacchetti, S; Mancinelli, R; Fanò, G; Mariggiò, M A

2009-04-01

SH-SY5Y neuroblastoma cells, a model for studying neuronal differentiation, are able to differentiate into either cholinergic or dopaminergic/adrenergic phenotypes depending on media conditions. Using this system, we asked whether guanosine (Guo) or guanosine-5'-triphosphate (GTP) are able to drive differentiation towards one particular phenotype. Differentiation was determined by evaluating the frequency of cells bearing neurites and assessing neurite length after exposure to different concentrations of Guo or GTP for different durations. After 6 days, 0.3 mM Guo or GTP induced a significant increase in the number of cells bearing neurites and increased neurite length. Western blot analyses confirmed that purines induced differentiation; cells exposed to purines showed increases in the levels of GAP43, MAP2, and tyrosine hydroxylase. Proliferation assays and cytofluorimetric analyses indicated a significant anti-proliferative effect of purines, and a concentration-dependent accumulation of cells in S-phase, starting after 24 h of purine exposure and extending for up to 6 days. A transcriptional profile analysis using gene arrays showed that an up-regulation of cyclin E2/cdk2 evident after 24 h was responsible for S-phase entry, and a concurrent down-regulation of cell-cycle progression-promoting cyclin B1/B2 prevented S-phase exit. In addition, patch-clamp recordings revealed that 0.3 mM Guo or GTP, after 6 day incubation, significantly decreased Na(+) currents. In conclusion, we showed Guo- and GTP-induced cell-cycle arrest in neuroblastoma cells and suggest that this makes these cells more responsive to differentiation processes that favor the dopaminergic/adrenergic phenotype.

Effects of nucleotides adenosine monophosphate and adenosine triphosphate in combination with L-arginine on male rabbit corpus cavernosum tissue.

PubMed

Hupertan, V; Neuzillet, Y; Stücker, O; Pons, C; Leammel, E; Lebret, T

2012-12-01

Purines and more specifically adenosine monophosphate (AMP) and adenosine triphosphate (ATP) have a strong relaxant effect on smooth muscle cells of the dog, rabbit and human corpus cavernosum, to approximately the same degree as nitric oxide (NO). However, purines are considered as modulators of erectile function rather than key mediators. This suggests that the use of purines combined with NO donors could be effective to treat some specific erectile disorders. The relaxation induced by the combination of l-arginine (Arg), a natural substrate for NO synthase, was assessed with a purine-nucleotide (AMP, ATP) on a rabbit corpus cavernosum model, to determine if these substances could potentiate each other's effect. When a pre-contraction was induced by phenylephrine, AMP alone induced a 43% CC relaxation rate and ATP alone a 26% rate. The relaxation rate induced by Arg was lower in comparison (8% at 5.10(-4) m vs. 25% at AMP 5.10(-4) m and 15% at ATP 5.10(-4) m). NO synthase inhibitor n-nitro-l-arginine did not modify the relaxing effect provoked by AMP suggesting that the mechanism of action of this nucleotide does not involve the NO pathway. The combination of Arg at 5.10(-4) m with either AMP or ATP at different doses ranging from 5.10(-4) to 10(-3) m significantly enhanced the relaxing response reaching rates of 62 and 80% respectively, leading to a synergistic effect. The present data indicate that a 'NO donor' combined with an 'adenosine donor' could be an effective therapeutic approach. © 2012 The Authors. International Journal of Andrology © 2012 European Academy of Andrology.

[Separation of purines, pyrimidines, pterins and flavonoids on magnolol-bonded silica gel stationary phase by high performance liquid chromatography].

PubMed

Chen, Hong; Li, Laishen; Zhang, Yang; Zhou, Rendan

2012-10-01

A new magnolol-bonded silica gel stationary phase (MSP) was used to separate the basic drugs including four purines, eight pyrimidines, four pterins and five flavonoids as polar representative samples by high performance liquid chromatography (HPLC). To clarify the separation mechanism, a commercial ODS column was also tested under the same chromatographic conditions. The high selectivities and fast baseline separations of the above drugs were achieved by using simple mobile phases on MSP. Although there is no end-caped treatment, the peak shapes of basic drugs containing nitrogen such as purines, pyrimidines and pterins were rather symmetrical on MSP, which indicated the the magnolol as ligand with multi-sites could shield the side effect of residual silanol groups on the surface of silica gel. Although somewhat different in the separation resolution, it was found that the elution orders of some drugs were generally similar on both MSP and ODS. The hydrophobic interaction should play a significant role in the separations of the above basic drugs, which was attributed to their reversed-phase property in the nature. However, MSP could provide the additional sites for many polar solutes, which was a rational explanation for the high selectivity of MSP. For example, in the separation of purines, pyrimidines and pterins on MSP, hydrogen-bonding and dipole-dipole interactions played leading roles besides hydrophobic interaction. Some solute molecules (such as mercaptopurine, vitexicarpin) and MSP can form the strong pi-pi stacking in the separation process. All enhanced the retention and improved the separation selectivity of MSP, which facilitated the separation of the basic drugs.

Identification of genes containing expanded purine repeats in the human genome and their apparent protective role against cancer.

PubMed

Singh, Himanshu Narayan; Rajeswari, Moganty R

2016-01-01

Purine repeat sequences present in a gene are unique as they have high propensity to form unusual DNA-triple helix structures. Friedreich's ataxia is the only human disease that is well known to be associated with DNA-triplexes formed by purine repeats. The purpose of this study was to recognize the expanded purine repeats (EPRs) in human genome and find their correlation with cancer pathogenesis. We developed "PuRepeatFinder.pl" algorithm to identify non-overlapping EPRs without pyrimidine interruptions in the human genome and customized for searching repeat lengths, n ≥ 200. A total of 1158 EPRs were identified in the genome which followed Wakeby distribution. Two hundred and ninety-six EPRs were found in geneic regions of 282 genes (EPR-genes). Gene clustering of EPR-genes was done based on their cellular function and a large number of EPR-genes were found to be enzymes/enzyme modulators. Meta-analysis of 282 EPR-genes identified only 63 EPR-genes in association with cancer, mostly in breast, lung, and blood cancers. Protein-protein interaction network analysis of all 282 EPR-genes identified proteins including those in cadherins and VEGF. The two observations, that EPRs can induce mutations under malignant conditions and that identification of some EPR-gene products in vital cell signaling-mediated pathways, together suggest the crucial role of EPRs in carcinogenesis. The new link between EPR-genes and their functionally interacting proteins throws a new dimension in the present understanding of cancer pathogenesis and can help in planning therapeutic strategies. Validation of present results using techniques like NGS is required to establish the role of the EPR genes in cancer pathology.

Structural Analysis of DFG-in and DFG-out Dual Src-Abl Inhibitors Sharing a Common Vinyl Purine Template

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Tianjun; Commodore, Lois; Huang, Wei-Sheng

2010-09-30

Bcr-Abl is the oncogenic protein tyrosine kinase responsible for chronic myeloid leukemia (CML). Treatment of the disease with imatinib (Gleevec) often results in drug resistance via kinase mutations at the advanced phases of the disease, which has necessitated the development of new mutation-resistant inhibitors, notably against the T315I gatekeeper mutation. As part of our efforts to discover such mutation resistant Abl inhibitors, we have focused on optimizing purine template kinase inhibitors, leading to the discovery of potent DFG-in and DFG-out series of Abl inhibitors that are also potent Src inhibitors. Here we present crystal structures of Abl bound by twomore » such inhibitors, based on a common N9-arenyl purine, and that represent both DFG-in and -out binding modes. In each structure the purine template is bound deeply in the adenine pocket and the novel vinyl linker forms a non-classical hydrogen bond to the gatekeeper residue, Thr315. Specific template substitutions promote either a DFG-in or -out binding mode, with the kinase binding site adjusting to optimize molecular recognition. Bcr-Abl T315I mutant kinase is resistant to all currently marketed Abl inhibitors, and is the focus of intense drug discovery efforts. Notably, our DFG-out inhibitor, AP24163, exhibits modest activity against this mutant, illustrating that this kinase mutant can be inhibited by DFG-out class inhibitors. Furthermore our DFG-out inhibitor exhibits dual Src-Abl activity, absent from the prototypical DFG-out inhibitor, imatinib as well as its analog, nilotinib. The data presented here provides structural guidance for the further design of novel potent DFG-out class inhibitors against Src, Abl and Abl T315I mutant kinases.« less

Altered erythrocyte nucleotide patterns are characteristic of inherited disorders of purine or pyrimidine metabolism.

PubMed

Simmonds, H A; Fairbanks, L D; Morris, G S; Webster, D R; Harley, E H

1988-02-15

This paper compares erythrocyte nucleotide levels in patients with eight different inherited purine or pyrimidine enzyme defects identified amongst a variety of patients referred predominantly for investigation of severe neurological abnormalities, or immunodeficiency syndromes. Characteristic nucleotide patterns were identified only in the six disorders (four involving purine and two pyrimidine metabolism) where there was clinical evidence of cellular toxicity. They were frequently related to the accumulation of abnormal metabolites in body fluids. These erythrocyte studies have demonstrated the following. 1. ATP depletion is not an invariable feature of adenosine deaminase (ADA) deficiency, but the accumulation of the deoxyribonucleotides dATP, or dGTP, is diagnostic of ADA, or purine nucleoside phosphorylase (PNP) deficiency, respectively. The early accumulation of dATP in foetal blood is a valuable aid to prenatal diagnosis of ADA deficiency. 2. GTP depletion appears to reflect the degree of CNS involvement in hypoxanthine-guanine phosphoribosyltransferase and PNP deficiency, as well as PP-ribose-P synthetase superactivity. Other diagnostic changes involving increased pyrimidine sugars and increased or decreased NAD levels, or ZTP in Lesch Nyhan erythrocytes, show no consistent correlation with the clinical manifestations. 3. These altered nucleotide levels afford a novel means for carrier detection of the X-linked defect associated with aberrant PP-ribose-P synthetase activity, where no other test is yet available. Measurement of erythrocyte nucleotide levels thus provides a simple and rapid aid to diagnosis and may sometimes be essential for determining prognosis, carrier detection, or monitoring therapy. These characteristic 'fingerprints' may give some insight into the mechanism by which the abnormal gene product produces disease. Such grossly altered nucleotide levels could also result in loss of erythrocyte flexibility, increased destruction and hence the anaemia, or other clinical manifestations, observed in some disorders.

Plasma Membrane-Located Purine Nucleotide Transport Proteins Are Key Components for Host Exploitation by Microsporidian Intracellular Parasites

PubMed Central

Heinz, Eva; Hacker, Christian; Dean, Paul; Mifsud, John; Goldberg, Alina V.; Williams, Tom A.; Nakjang, Sirintra; Gregory, Alison; Hirt, Robert P.; Lucocq, John M.; Kunji, Edmund R. S.; Embley, T. Martin

2014-01-01

Microsporidia are obligate intracellular parasites of most animal groups including humans, but despite their significant economic and medical importance there are major gaps in our understanding of how they exploit infected host cells. We have investigated the evolution, cellular locations and substrate specificities of a family of nucleotide transport (NTT) proteins from Trachipleistophora hominis, a microsporidian isolated from an HIV/AIDS patient. Transport proteins are critical to microsporidian success because they compensate for the dramatic loss of metabolic pathways that is a hallmark of the group. Our data demonstrate that the use of plasma membrane-located nucleotide transport proteins (NTT) is a key strategy adopted by microsporidians to exploit host cells. Acquisition of an ancestral transporter gene at the base of the microsporidian radiation was followed by lineage-specific events of gene duplication, which in the case of T. hominis has generated four paralogous NTT transporters. All four T. hominis NTT proteins are located predominantly to the plasma membrane of replicating intracellular cells where they can mediate transport at the host-parasite interface. In contrast to published data for Encephalitozoon cuniculi, we found no evidence for the location for any of the T. hominis NTT transporters to its minimal mitochondria (mitosomes), consistent with lineage-specific differences in transporter and mitosome evolution. All of the T. hominis NTTs transported radiolabelled purine nucleotides (ATP, ADP, GTP and GDP) when expressed in Escherichia coli, but did not transport radiolabelled pyrimidine nucleotides. Genome analysis suggests that imported purine nucleotides could be used by T. hominis to make all of the critical purine-based building-blocks for DNA and RNA biosynthesis during parasite intracellular replication, as well as providing essential energy for parasite cellular metabolism and protein synthesis. PMID:25474405

Fibroblast Growth Factor 23 Levels Associate with AKI and Death in Critical Illness.

PubMed

Leaf, David E; Jacob, Kirolos A; Srivastava, Anand; Chen, Margaret E; Christov, Marta; Jüppner, Harald; Sabbisetti, Venkata S; Martin, Aline; Wolf, Myles; Waikar, Sushrut S

2017-06-01

Elevated plasma levels of the osteocyte-derived hormone fibroblast growth factor 23 (FGF23) have emerged as a powerful biomarker of cardiovascular disease and death in patients with CKD. Whether elevated urinary or plasma FGF23 levels are prospectively associated with AKI and death in critically ill patients is unknown. We therefore conducted a prospective cohort study of 350 critically ill patients admitted to intensive care units at an academic medical center to investigate whether higher urinary FGF23 levels associate with the composite end point of AKI or in-hospital mortality (AKI/death). We measured urinary FGF23 levels within 24 hours of admission to the intensive care unit. In a subcohort ( n =131) we also measured plasma levels of FGF23, calcium, phosphate, parathyroid hormone, and vitamin D metabolites. Urinary and plasma FGF23 levels, but not other mineral metabolites, significantly associated with AKI/death. In multivariate analyses, patients in the highest compared with the lowest quartile of urinary FGF23 had a 3.9 greater odds (95% confidence interval, 1.6 to 9.5) of AKI/death. Higher urinary FGF23 levels also independently associated with greater hospital, 90-day, and 1-year mortality; longer length of stay; and several other important adverse outcomes. In conclusion, elevated FGF23 levels measured in the urine or plasma may be a promising novel biomarker of AKI, death, and other adverse outcomes in critically ill patients. Copyright © 2017 by the American Society of Nephrology.

Biofabricated Structures Reconstruct Functional Urinary Bladders in Radiation-injured Rat Bladders.

PubMed

Imamura, Tetsuya; Shimamura, Mitsuru; Ogawa, Teruyuki; Minagawa, Tomonori; Nagai, Takashi; Silwal Gautam, Sudha; Ishizuka, Osamu

2018-05-08

The ability to repair damaged urinary bladders through the application of bone marrow-derived cells is in the earliest stages of development. We investigated the application of bone marrow-derived cells to repair radiation-injured bladders. We used a three-dimensional (3D) bioprinting robot system to biofabricate bone marrow-derived cell structures. We then determined if the biofabricated structures could restore the tissues and functions of radiation-injured bladders. The bladders of female 10-week-old Sprague-Dawley (SD) rats were irradiated with 2-Gy once a week for 5 weeks. Adherent and proliferating bone marrow-derived cells harvested from the femurs of male 17-week-old green fluorescence protein-transfected Tg-SD rats were cultured in collagen-coated flasks. Bone marrow-derived cell spheroids were formed in 96-well plates. Three layers of spheroids were assembled by the bioprinter onto a 9x9 microneedle array. The assembled spheroids were perfusion cultured for 7 days, and then the microneedle array was removed. Two weeks after the last radiation treatment, the biofabricated structures were transplanted into an incision on the anterior wall of the bladders (n=10). Control rats received the same surgery but without the biofabricated structures (sham-structure, n=12). At 2 and 4 weeks after surgery, the sham-structure control bladder tissues exhibited disorganized smooth muscle layers, decreased nerve cells, and significant fibrosis with increased presence of fibrosis-marker P4HB-positive cells and hypoxia-marker HIF1α-positive cells. The transplanted structures survived within the recipient tissues, and blood vessels extended within them from the recipient tissues. The bone marrow-derived cells in the structures differentiated into smooth muscle cells and formed smooth muscle clusters. The recipient tissues near the transplanted structures had distinct smooth muscle layers and reconstructed nerve cells, and only minimal fibrosis with decreased presence of P4HB- and HIF1α-positive cells. At 4 weeks after surgery, the sham-structure control rats exhibited significant urinary frequency symptoms with irregular and short voiding intervals, and low micturition volumes. In contrast, the structure-transplanted rats had regular micturition with longer voiding intervals and higher micturition volumes compared to the control rats. Further, the residual volume of the structure-transplanted rats was lower than for the controls. Therefore, transplantation of biofabricated bone marrow-derived cell structures reconstructed functional bladders.

Compositions containing nucleosides and manganese and their uses

DOEpatents

Daly, Michael J.; Gaidamakova, Elena K.; Matrosova, Vera Y.; Levine, Rodney L.; Wehr, Nancy B.

2015-11-17

This invention encompasses methods of preserving protein function by contacting a protein with a composition comprising one or more purine or pyrimidine nucleosides (such as e.g., adenosine or uridine) and an antioxidant (such as e.g., manganese). In addition, the invention encompasses methods of treating and/or preventing a side effect of radiation exposure and methods of preventing a side effect of radiotherapy comprising administration of a pharmaceutically effective amount of a composition comprising one or more purine or pyrimidine nucleosides (such as e.g., adenosine or uridine) and an antioxidant (such as e.g., manganese) to a subject in need thereof. The compositions may comprise D. radiodurans extracts.

Factors Which Increase Acid Production in Milk by Lactobacilli

PubMed Central

Huhtanen, C. N.; Williams, W. L.

1963-01-01

The stimulation by yeast extract of acid production in milk by various lactobacilli was studied. It was found that supplementing milk with purine and pyrimidine bases and amino acids allowed nearly maximal acid production by Lactobacillus bulgaricus strain 7994, L. acidophilus 4796, 4356, and 4357, and L. leichmannii 326 and 327. Further supplementation with deoxyribotides allowed maximal acid production by L. acidophilus 204, but L. acidophilus 207 required adenosine or adenylic acid. L. casei strain 7469 showed no appreciable response to the amino acids or purine and pyrimidine bases, and is presumed to require an unidentified factor in corn steep liquor. PMID:13955610

[Regulation of age-dependent phenomena. Influence of C6-substituted purines on cell aggregation and cell migration in primary cultures of lense epithelial cells].

PubMed

Glässer, D; Iwig, M; Weber, E

1975-01-01

The existence of an age dependent latent period of cell emigration has been proved in the primary culture of epithelial cells of bovine lenses. The previously described aggregation phenomenon as well as the latent period of the cell emigration increase with the age of the sponsor animals. Extracellular adenine and other C6-substituted purines, isolated from the cells themselves and added to the medium, act the same way on the lens cells in the primary culture as the increasing age of the sponsor animals. Adenine stimulates cell aggregation and inhibits the adhesion of the cells to the substratum, the cell flattening and the cell migration. The adenine action has been proved down to a concentration of 3 X 10(-6) M. During the primary culture, the lens cells gradually los the adenine sensitivity. The adenine action also occurs on single cells, isolated by trypsination, it differs from the reaction of ouabain and can be removed at low concentration by washing procedures. The results favour the suggestion C6-substituted purines to be involved in cell ageing.

Transport of adenine, hypoxanthine and uracil into Escherichia coli.

PubMed Central

Burton, K

1977-01-01

Uptake of adenine, hypoxanthine and uracil by an uncA strain of Escherichia coli is inhibited by uncouplers or when phosphate in the medium is replaced by less than 1 mM-arsenate, indicating a need for both a protonmotive force and phosphorylated metabolites. The rate of uptake of adenine or hypoxanthine was not markedly affected by a genetic deficiency of purine nucleoside phosphorylase. In two mutants with undetected adenine phosphoribosyltransferase, the rate of adenine uptake was about 30% of that in their parent strain, and evidence was obtained to confirm that adenine had then been utilized via purine nucleoside phosphorylase. In a strain deficient in both enzymes adenine uptake was about 1% of that shown by wild-type strains. Uptake of hypoxanthine was similarly limited in a strain lacking purine nucleoside phosphorylase, hypoxanthine phosphoribosyltransferase and guanine phosphoribosyltransferase. Deficiency of uracil phosphoribosyltransferase severely limits uracil uptake, but the defect can be circumvented by addition of inosine, which presumably provides ribose 1-phosphate for reversal of uridine phosphorylase. The results indicate that there are porter systems for adenine, hypoxanthine and uracil dependent on a protonmotive force and facilitated by intracellular metabolism of the free bases. PMID:413544

Microwave-assisted synthesis of novel purine nucleosides as selective cholinesterase inhibitors.

PubMed

Schwarz, S; Csuk, R; Rauter, A P

2014-04-21

Alzheimer's disease (AD), the most common form of senile dementia, is characterized by high butyrylcholinesterase (BChE) levels in the brain in later AD stages, for which no treatment is available. Pursuing our studies on selective BChE inhibitors, that may contribute to understand the role of this enzyme in disease progression, we present now microwave-assisted synthesis and anticholinesterase activity of a new nucleoside series embodying 6-chloropurine or 2-acetamido-6-chloropurine linked to D-glucosyl, D-galactosyl and D-mannosyl residues. It was designed to assess the contribution of sugar stereochemistry, purine structure and linkage to the sugar for cholinesterase inhibition efficiency and selectivity. Compounds were subjected to Ellman's assay and their inhibition constants determined. The α-anomers were the most active compounds, while selectivity for BChE or acetylcholinesterase (AChE) inhibition could be tuned by the purine base, by the glycosyl moiety and by N(7)-ligation. Some of the nucleosides were far more potent than the drug galantamine, and the most promising competitive and selective BChE inhibitor, the N(7)-linked 2-acetamido-α-D-mannosylpurine, showed a Ki of 50 nM and a selectivity factor of 340 fold for BChE over AChE.

GMP Synthase Is Required for Virulence Factor Production and Infection by Cryptococcus neoformans*

PubMed Central

Chitty, Jessica L.; Tatzenko, Tayla L.; Williams, Simon J.; Koh, Y. Q. Andre E.; Corfield, Elizabeth C.; Butler, Mark S.; Robertson, Avril A. B.; Cooper, Matthew A.; Kappler, Ulrike; Kobe, Bostjan; Fraser, James A.

2017-01-01

Over the last four decades the HIV pandemic and advances in medical treatments that also cause immunosuppression have produced an ever-growing cohort of individuals susceptible to opportunistic pathogens. Of these, AIDS patients are particularly vulnerable to infection by the encapsulated yeast Cryptococcus neoformans. Most commonly found in the environment in purine-rich bird guano, C. neoformans experiences a drastic change in nutrient availability during host infection, ultimately disseminating to colonize the purine-poor central nervous system. Investigating the consequences of this challenge, we have characterized C. neoformans GMP synthase, the second enzyme in the guanylate branch of de novo purine biosynthesis. We show that in the absence of GMP synthase, C. neoformans becomes a guanine auxotroph, the production of key virulence factors is compromised, and the ability to infect nematodes and mice is abolished. Activity assays performed using recombinant protein unveiled differences in substrate binding between the C. neoformans and human enzymes, with structural insights into these kinetic differences acquired via homology modeling. Collectively, these data highlight the potential of GMP synthase to be exploited in the development of new therapeutic agents for the treatment of disseminated, life-threatening fungal infections. PMID:28062578

Purine 5‧,8-cyclo-2‧-deoxynucleoside lesions in irradiated DNA

NASA Astrophysics Data System (ADS)

Chatgilialoglu, Chryssostomos; Krokidis, Marios G.; Papadopoulos, Kyriakos; Terzidis, Michael A.

2016-11-01

Having their position gained among the smallest bulky DNA lesions recognized by the nucleotide excision repair (NER) enzyme, purine 5‧,8-cyclo-2‧-deoxynucleosides (5‧,8-cPu) are increasingly attracting the interest in the field of genome integrity in health and diseases. Exclusively generated by one of the most harmful of the reactive oxygen species, the hydroxyl radical, 5‧,8-cPu can be utilized also for highly valuable information regarding the oxidative status nearby the area where the genetic information is stored. Herein, we have collected the most recently reported biological studies, focusing on the repair mechanism of these lesions and their biological significance particularly in transcription. The LC-MS/MS quantification protocols that appeared in the literature are discussed in details, along with the reported values for the four 5‧,8-cPu produced by in vitro γ-radiolysis experiments with calf thymus DNA. Mechanistic insights in the formation of the purine 5‧,8-cyclo-2‧-deoxynucleosides and their chemical stability are also given in the light of their potential to be utilized as DNA biomarkers of oxidative stress.

Investigations into the origin of the molecular recognition of several adenosine deaminase inhibitors.

PubMed

Gillerman, Irina; Fischer, Bilha

2011-01-13

Inhibitors of adenosine deaminase (ADA, EC 3.5.4.4) are potential therapeutic agents for the treatment of various health disorders. Several highly potent inhibitors were previously identified, yet they exhibit unacceptable toxicities. We performed a SAR study involving a series of C2 or C8 substituted purine-riboside analogues with a view to discover less potent inhibitors with a lesser toxicity. We found that any substitution at C8 position of nebularine resulted in total loss of activity toward calf intestinal ADA. However, several 2-substituted-adenosine, 8-aza-adenosine, and nebularine analogues exhibited inhibitory activity. Specifically, 2-Cl-purine riboside, 8-aza-2-thiohexyl adenosine, 2-thiohexyl adenosine, and 2-MeS-purine riboside were found to be competitive inhibitors of ADA with K(i) values of 25, 22, 6, and 3 μM, respectively. We concluded that electronic parameters are not major recognition determinants of ADA but rather steric parameters. A C2 substituent which fits ADA hydrophobic pocket and improves H-bonding with the enzyme makes a good inhibitor. In addition, a gg rotamer about C4'-C5' bond is apparently an important recognition determinant.

Multiple sclerosis: evaluation of purine nucleotide metabolism in central nervous system in association with serum levels of selected fat-soluble antioxidants.

PubMed

Kuračka, Lubomír; Kalnovičová, Terézia; Kucharská, Jarmila; Turčáni, Peter

2014-01-01

In the pathogenesis of demyelinating diseases including multiple sclerosis (MS) an important role is played by oxidative stress. Increased energy requirements during remyelination of axons and mitochondria failure is one of the causes of axonal degeneration and disability in MS. In this context, we analyzed to what extent the increase in purine catabolism is associated with selected blood lipophilic antioxidants and if there is any association with alterations in serum levels of coenzyme Q10. Blood serum and cerebrospinal fluid (CSF) samples from 42 patients with diagnosed MS and 34 noninflammatory neurologic patients (control group) were analyzed. Compared to control group, MS patients had significantly elevated values of all purine nucleotide metabolites, except adenosine. Serum lipophilic antioxidants γ -tocopherol, β -carotene, and coenzyme Q10 for the vast majority of MS patients were deficient or moved within the border of lower physiological values. Serum levels of TBARS, marker of lipid peroxidation, were increased by 81% in the MS patients. The results indicate that the deficit of lipophilic antioxidants in blood of MS patients may have a negative impact on bioenergetics of reparative remyelinating processes and promote neurodegeneration.

Metabolic Profiles and Free Radical Scavenging Activity of Cordyceps bassiana Fruiting Bodies According to Developmental Stage

PubMed Central

Hyun, Sun-Hee; Lee, Seok-Young; Sung, Gi-Ho; Kim, Seong Hwan; Choi, Hyung-Kyoon

2013-01-01

The metabolic profiles of Cordyceps bassiana according to fruiting body developmental stage were investigated using gas chromatography-mass spectrometry. We were able to detect 62 metabolites, including 48 metabolites from 70% methanol extracts and 14 metabolites from 100% n-hexane extracts. These metabolites were classified as alcohols, amino acids, organic acids, phosphoric acids, purine nucleosides and bases, sugars, saturated fatty acids, unsaturated fatty acids, or fatty amides. Significant changes in metabolite levels were found according to developmental stage. Relative levels of amino acids, purine nucleosides, and sugars were higher in development stage 3 than in the other stages. Among the amino acids, valine, isoleucine, lysine, histidine, glutamine, and aspartic acid, which are associated with ABC transporters and aminoacyl-tRNA biosynthesis, also showed higher levels in stage 3 samples. The free radical scavenging activities, which were significantly higher in stage 3 than in the other stages, showed a positive correlation with purine nucleoside metabolites such as adenosine, guanosine, and inosine. These results not only show metabolic profiles, but also suggest the metabolic pathways associated with fruiting body development stages in cultivated C. bassiana. PMID:24058459

Reduction of the degradation activity of umami-enhancing purinic ribonucleotide supplement in miso by the targeted suppression of acid phosphatases in the Aspergillus oryzae starter culture.

PubMed

Marui, Junichiro; Tada, Sawaki; Fukuoka, Mari; Wagu, Yutaka; Shiraishi, Yohei; Kitamoto, Noriyuki; Sugimoto, Tatsuya; Hattori, Ryota; Suzuki, Satoshi; Kusumoto, Ken-Ichi

2013-09-02

Miso (fermented soybean paste) is a traditional Japanese fermented food, and is now used worldwide. The solid-state culture of filamentous fungus, Aspergillus oryzae, grown on rice is known as rice-koji, and is important as a starter for miso fermentation because of its prominent hydrolytic enzyme activities. Recently, commercial miso products have been supplemented with purinic ribonucleotides, such as inosine monophosphate (IMP) and guanine monophosphate, to enhance the characteristic umami taste of glutamate in miso. Because the purinic ribonucleotides are degraded by enzymes such as acid phosphatases in miso, heat inactivation is required prior to the addition of these flavorings. However, heat treatment is a costly process and reduces the quality of miso. Therefore, an approach to lower acid phosphatase activities in koji culture is necessary. Transcriptional analysis using an A. oryzae KBN8048 rice-koji culture showed that eight of the 13 acid phosphatase (aph) genes were significantly down-regulated by the addition of phosphoric acid in the preparation of the culture in a concentration-dependent manner, while aphC expression was markedly up-regulated under the same conditions. The eight down-regulated genes might be under the control of the functional counterpart of the Saccharomyces cerevisiae transcriptional activator Pho4, which specifically regulates phosphatase genes in response to the ambient phosphate availability. However, the regulatory mechanism of aphC was not clear. The IMP dephosphorylation activities in rice-koji cultures of KBN8048 and the aphC deletion mutant (ΔaphC) were reduced by up to 30% and 70%, respectively, in cultures with phosphoric acid, while protease and amylase activity, which is important for miso fermentation, was minimally affected. The miso products fermented using the rice-koji cultures of KBN8048 and ΔaphC prepared with phosphoric acid had reductions in IMP dephosphorylation activity of 80% and 90%, respectively, without any adverse effects on amylase and protease activities. Thus, preparing the A. oryzae rice-koji culture under phosphate-sufficient conditions preferentially produces a fermentation starter of miso exhibiting low purinic ribonucleotide dephosphorylation activity. Moreover, aphC is a potential breeding target to reduce purinic ribonucleotide degradation activity further in commercial miso products. © 2013 Elsevier B.V. All rights reserved.

PDT for malignant tumors: a clinical analysis of 152 cases

NASA Astrophysics Data System (ADS)

Zhuang, Shi-Zhang; Wang, Yun-Zhen; Li, Xin; Zhang, Changjun; Wang, Jian-Zhao; Zhang, Da-Ren

1993-03-01

Hematoporphyrin derivative (HPD) laser photodynamic therapy (PDT) was applied for the patients of 152 cases of malignant tumors, including tumors of the lip, tongue, esophagus, urinary bladder, skin, larynx, vagina, etc. Since early 1981 good results have been obtained.

mPGES-1-derived PGE2 mediates dehydration natriuresis

PubMed Central

Jia, Zhanjun; Liu, Gang; Sun, Ying; Kakizoe, Yutaka; Guan, Guangju; Zhang, Aihua; Zhou, Shu-Feng

2013-01-01

PGE2 is a natriuretic factor whose production is elevated after water deprivation (WD) but its role in dehydration natriuresis is not well-defined. The goal of the present study was to investigate the role of microsomal prostaglandin E synthase-1 (mPGES-1) in dehydration natriuresis. After 24-h WD, wild-type (WT) mice exhibited a significant increase in 24-h urinary Na+ excretion accompanied with normal plasma Na+ concentration and osmolality. In contrast, WD-induced elevation of urinary Na+ excretion was completely abolished in mPGES-1 knockout (KO) mice in parallel with increased plasma Na+ concentration and a trend increase in plasma osmolality. WD induced a 1.8-fold increase in urinary PGE2 output and a 1.6-fold increase in PGE2 content in the renal medulla of WT mice, both of which were completely abolished by mPGES-1 deletion. Similar patterns of changes were observed for urinary nitrate/nitrite and cGMP. The natriuresis in dehydrated WT mice was associated with a significant downregulation of renal medullary epithelial Na channel-α mRNA and protein, contrasting to unaltered expressions in dehydrated KO mice. By quantitative RT-PCR, WD increased the endothelial nitric oxide synthase (eNOS), inducible NOS, and neuronal NOS expressions in the renal medulla of WT mice by 3.9-, 1.48-, and 2.6-fold, respectively, all of which were significantly blocked in mPGES-1 KO mice. The regulation of eNOS expression was further confirmed by immunoblotting. Taken together, our results suggest that mPGES-1-derived PGE2 contributes to dehydration natriuresis likely via NO/cGMP. PMID:23171554

Detection of fenspiride and identification of in vivo metabolites in horse body fluids by capillary gas chromatography-mass spectrometry: administration, biotransformation and urinary excretion after a single oral dose.

PubMed

Dumasia, M C; Houghton, E; Hyde, W; Greulich, D; Nelson, T; Peterson, Jackie

2002-02-05

Studies related to the in vivo biotransforrmation and urinary excretion of fenspiride hydrochloride in the horse are described. After oral administration, the drug is metabolised by both phase I functionalisation and phase II conjugation pathways. Following enzymatic deconjugation, fenspiride and its phase I metabolites were isolated from post-administration biofluids using bonded co-polymeric mixed mode solid-phase extraction cartridges to isolate the basic compounds. Following trimethylsilylation (TMS), the parent drug and metabolites were identified by capillary gas chromatography-mass spectrometry (GC-MS). Fenspiride (A) and seven metabolites (B-->G) arising from oxidation on both the aromatic and heterocyclic substructures were detected in urine. The positive ion electron ionisation mass spectra of the TMS derivatives of fenspiride and its metabolites provided useful information on its metabolism. Positive ion methane chemical ionisation-GC-MS of the derivatives provided both derivatised molecular mass and structural information. Unchanged fenspiride can be detected in post-administration plasma and urine samples for up to 24 h. Maximum urinary levels of 100-200 ng ml(-1) were observed between 3 and 5 h after administration. After enzymatic deconjugation, the major phenolic metabolite (G) can be detected in urine for up to 72 h. This metabolite is the analyte of choice in the GC-MS screening of post-race equine urine samples for detection of fenspiride use. However, a distinct difference was observed in the urinary excretion of this metabolite between the thoroughbred horses used in UK study and the quarterbred and standardbred horses used for the USA administrations.

The Hedgehog Signal Induced Modulation of Bone Morphogenetic Protein Signaling: An Essential Signaling Relay for Urinary Tract Morphogenesis

PubMed Central

Nakagata, Naomi; Miyagawa, Shinichi; Suzuki, Kentaro; Kitazawa, Sohei; Yamada, Gen

2012-01-01

Background Congenital diseases of the urinary tract are frequently observed in infants. Such diseases present a number of developmental anomalies such as hydroureter and hydronephrosis. Although some genetically-modified mouse models of growth factor signaling genes reproduce urinary phenotypes, the pathogenic mechanisms remain obscure. Previous studies suggest that a portion of the cells in the external genitalia and bladder are derived from peri-cloacal mesenchymal cells that receive Hedgehog (Hh) signaling in the early developmental stages. We hypothesized that defects in such progenitor cells, which give rise to urinary tract tissues, may be a cause of such diseases. Methodology/Principal Findings To elucidate the pathogenic mechanisms of upper urinary tract malformations, we analyzed a series of Sonic hedgehog (Shh) deficient mice. Shh−/− displayed hydroureter and hydronephrosis phenotypes and reduced expression of several developmental markers. In addition, we suggested that Shh modulation at an early embryonic stage is responsible for such phenotypes by analyzing the Shh conditional mutants. Tissue contribution assays of Hh-responsive cells revealed that peri-cloacal mesenchymal cells, which received Hh signal secreted from cloacal epithelium, could contribute to the ureteral mesenchyme. Gain- and loss-of-functional mutants for Hh signaling revealed a correlation between Hh signaling and Bone morphogenetic protein (Bmp) signaling. Finally, a conditional ablation of Bmp receptor type IA (BmprIA) gene was examined in Hh-responsive cell lineages. This system thus made it possible to analyze the primary functions of the growth factor signaling relay. The defective Hh-to-Bmp signaling relay resulted in severe urinary tract phenotypes with a decrease in the number of Hh-responsive cells. Conclusions/Significance This study identified the essential embryonic stages for the pathogenesis of urinary tract phenotypes. These results suggested that Hh-responsive mesenchymal Bmp signaling maintains the population of peri-cloacal mesenchyme cells, which is essential for the development of the ureter and the upper urinary tract. PMID:22860096

Metabolomic Profiling of Extracellular Vesicles and Alternative Normalization Methods Reveal Enriched Metabolites and Strategies to Study Prostate Cancer-Related Changes

PubMed Central

Puhka, Maija; Takatalo, Maarit; Nordberg, Maria-Elisa; Valkonen, Sami; Nandania, Jatin; Aatonen, Maria; Yliperttula, Marjo; Laitinen, Saara; Velagapudi, Vidya; Mirtti, Tuomas; Kallioniemi, Olli; Rannikko, Antti; Siljander, Pia R-M; af Hällström, Taija Maria

2017-01-01

Body fluids are a rich source of extracellular vesicles (EVs), which carry cargo derived from the secreting cells. So far, biomarkers for pathological conditions have been mainly searched from their protein, (mi)RNA, DNA and lipid cargo. Here, we explored the small molecule metabolites from urinary and platelet EVs relative to their matched source samples. As a proof-of-concept study of intra-EV metabolites, we compared alternative normalization methods to profile urinary EVs from prostate cancer patients before and after prostatectomy and from healthy controls. Methods: We employed targeted ultra-performance liquid chromatography-tandem mass spectrometry to profile over 100 metabolites in the isolated EVs, original urine samples and platelets. We determined the enrichment of the metabolites in the EVs and analyzed their subcellular origin, pathways and relevant enzymes or transporters through data base searches. EV- and urine-derived factors and ratios between metabolites were tested for normalization of the metabolomics data. Results: Approximately 1 x 1010 EVs were sufficient for detection of metabolite profiles from EVs. The profiles of the urinary and platelet EVs overlapped with each other and with those of the source materials, but they also contained unique metabolites. The EVs enriched a selection of cytosolic metabolites including members from the nucleotide and spermidine pathways, which linked to a number of EV-resident enzymes or transporters. Analysis of the urinary EVs from the patients indicated that the levels of glucuronate, D-ribose 5-phosphate and isobutyryl-L-carnitine were 2-26-fold lower in all pre-prostatectomy samples compared to the healthy control and post-prostatectomy samples (p < 0.05). These changes were only detected from EVs by normalization to EV-derived factors or with metabolite ratios, and not from the original urine samples. Conclusions: Our results suggest that metabolite analysis of EVs from different samples is feasible using a high-throughput platform and relatively small amount of sample material. With the knowledge about the specific enrichment of metabolites and normalization methods, EV metabolomics could be used to gain novel biomarker data not revealed by the analysis of the original EV source materials. PMID:29109780

Purinergic Signaling in the Cardiovascular System.

PubMed

Burnstock, Geoffrey

2017-01-06

There is nervous control of the heart by ATP as a cotransmitter in sympathetic, parasympathetic, and sensory-motor nerves, as well as in intracardiac neurons. Centers in the brain control heart activities and vagal cardiovascular reflexes involve purines. Adenine nucleotides and nucleosides act on purinoceptors on cardiomyocytes, AV and SA nodes, cardiac fibroblasts, and coronary blood vessels. Vascular tone is controlled by a dual mechanism. ATP, released from perivascular sympathetic nerves, causes vasoconstriction largely via P2X1 receptors. Endothelial cells release ATP in response to changes in blood flow (via shear stress) or hypoxia, to act on P2 receptors on endothelial cells to produce nitric oxide, endothelium-derived hyperpolarizing factor, or prostaglandins to cause vasodilation. ATP is also released from sensory-motor nerves during antidromic reflex activity, to produce relaxation of some blood vessels. Purinergic signaling is involved in the physiology of erythrocytes, platelets, and leukocytes. ATP is released from erythrocytes and platelets, and purinoceptors and ectonucleotidases are expressed by these cells. P1, P2Y 1 , P2Y 12 , and P2X1 receptors are expressed on platelets, which mediate platelet aggregation and shape change. Long-term (trophic) actions of purine and pyrimidine nucleosides and nucleotides promote migration and proliferation of vascular smooth muscle and endothelial cells via P1 and P2Y receptors during angiogenesis, vessel remodeling during restenosis after angioplasty and atherosclerosis. The involvement of purinergic signaling in cardiovascular pathophysiology and its therapeutic potential are discussed, including heart failure, infarction, arrhythmias, syncope, cardiomyopathy, angina, heart transplantation and coronary bypass grafts, coronary artery disease, diabetic cardiomyopathy, hypertension, ischemia, thrombosis, diabetes mellitus, and migraine. © 2017 American Heart Association, Inc.

Prominent Steatosis with Hypermetabolism of the Cell Line Permissive for Years of Infection with Hepatitis C Virus

PubMed Central

Sugiyama, Kazuo; Ebinuma, Hirotoshi; Nakamoto, Nobuhiro; Sakasegawa, Noriko; Murakami, Yuko; Chu, Po-sung; Usui, Shingo; Ishibashi, Yuka; Wakayama, Yuko; Taniki, Nobuhito; Murata, Hiroko; Saito, Yoshimasa; Fukasawa, Masayoshi; Saito, Kyoko; Yamagishi, Yoshiyuki; Wakita, Takaji; Takaku, Hiroshi; Hibi, Toshifumi; Saito, Hidetsugu; Kanai, Takanori

2014-01-01

Most of experiments for HCV infection have been done using lytic infection systems, in which HCV-infected cells inevitably die. Here, to elucidate metabolic alteration in HCV-infected cells in a more stable condition, we established an HCV-persistently-infected cell line, designated as HPI cells. This cell line has displayed prominent steatosis and supported HCV infection for more than 2 years, which is the longest ever reported. It enabled us to analyze metabolism in the HCV-infected cells integrally combining metabolomics and expression arrays. It revealed that rate-limiting enzymes for biosynthesis of cholesterol and fatty acids were up-regulated with actual increase in cholesterol, desmosterol (cholesterol precursor) and pool of fatty acids. Notably, the pentose phosphate pathway was facilitated with marked up-regulation of glucose-6-phosphate dehydrogenase, a rete-limiting enzyme, with actual increase in NADPH. In its downstream, enzymes for purine synthesis were also up-regulated resulting in increase of purine. Contrary to common cancers, the TCA cycle was preferentially facilitated comparing to glycolysis pathway with a marked increase of most of amino acids. Interestingly, some genes controlled by nuclear factor (erythroid-derived 2)-like 2 (Nrf2), a master regulator of antioxidation and metabolism, were constitutively up-regulated in HPI cells. Knockdown of Nrf2 markedly reduced steatosis and HCV infection, indicating that Nrf2 and its target genes play important roles in metabolic alteration and HCV infection. In conclusion, HPI cell is a bona fide HCV-persistently-infected cell line supporting HCV infection for years. This cell line sustained prominent steatosis in a hypermetabolic status producing various metabolites. Therefore, HPI cell is a potent research tool not only for persistent HCV infection but also for liver metabolism, overcoming drawbacks of the lytic infection systems. PMID:24718268

Methodologies for Estimating Cumulative Human Exposures to Current-Use Pyrethroid Pesticides

EPA Science Inventory

We estimated cumulative residential pesticide exposures for a group of nine young children (4–6 years) using three different methodologies developed by the US Environmental Protection Agency and compared the results with estimates derived from measured urinary metabolite concentr...

Dual-energy CT for the characterization of urinary calculi: In vitro and in vivo evaluation of a low-dose scanning protocol.

PubMed

Thomas, C; Patschan, O; Ketelsen, D; Tsiflikas, I; Reimann, A; Brodoefel, H; Buchgeister, M; Nagele, U; Stenzl, A; Claussen, C; Kopp, A; Heuschmid, M; Schlemmer, H-P

2009-06-01

The efficiency and radiation dose of a low-dose dual-energy (DE) CT protocol for the evaluation of urinary calculus disease were evaluated. A low-dose dual-source DE-CT renal calculi protocol (140 kV, 46 mAs; 80 kV, 210 mAs) was derived from the single-energy (SE) CT protocol used in our institution for the detection of renal calculi (120 kV, 75 mAs). An Alderson-Rando phantom was equipped with thermoluminescence dosimeters and examined by CT with both protocols. The effective doses were calculated. Fifty-one patients with suspected or known urinary calculus disease underwent DE-CT. DE analysis was performed if calculi were detected using a dedicated software tool. Results were compared to chemical analysis after invasive calculus extraction. An effective dose of 3.43 mSv (male) and 5.30 mSv (female) was measured in the phantom for the DE protocol (vs. 3.17/4.57 mSv for the SE protocol). Urinary calculi were found in 34 patients; in 28 patients, calculi were removed and analyzed (23 patients with calcified calculi, three with uric acid calculi, one with 2,8-dihyxdroxyadenine-calculi, one patient with a mixed struvite calculus). DE analysis was able to distinguish between calcified and non-calcified calculi in all cases. In conclusion, dual-energy urinary calculus analysis is effective also with a low-dose protocol. The protocol tested in this study reliably identified calcified urinary calculi in vivo.

Insulin resistance and the relationship between urinary Na(+)/K(+) and ambulatory blood pressure in a community of African ancestry.

PubMed

Millen, Aletta M E; Norton, Gavin R; Majane, Olebogeng H I; Maseko, Muzi J; Brooksbank, Richard; Michel, Frederic S; Snyman, Tracy; Sareli, Pinhas; Woodiwiss, Angela J

2013-05-01

Although groups of African descent are particularly sensitive to blood pressure (BP) effects of salt intake, the role of obesity and insulin resistance in mediating this effect is uncertain. We determined whether obesity or insulin resistance is independently associated with urinary Na(+)/K(+)-BP relationships in a community sample of African ancestry. We measured 24-hour urinary Na(+)/K(+), homeostasis model assessment of insulin resistance (HOMA-IR), and nurse-derived conventional and 24-hour ambulatory BP in 331 participants from a South African community sample of black African descent not receiving treatment for hypertension. With adjustments for diabetes mellitus and the individual terms, an interaction between waist circumference and urinary Na(+)/K(+) was associated with day diastolic BP (P < 0.05) and an interaction between log HOMA-IR and urinary Na(+)/K(+) was associated with 24-hour and day systolic (P < 0.05) and 24-hour, day, and night diastolic (P < 0.002; P < 0.001) BP. The multivariable-adjusted relationship between urinary Na(+)/K(+) and night diastolic BP increased across tertiles of HOMA-IR (tertile 1: β-coefficient = -0.79 ± 0.47; tertile 2: β-coefficient = 0.65 ± 0.35; tertile 3: β-coefficient = 1.03 ± 0.46; P < 0.05 tertiles 3 and 2 vs. 1). The partial correlation coefficients for relationships between urinary Na(+)/K(+) and 24-hour (partial r = 0.19; P < 0.02), day (partial r = 0.17; P < 0.05), and night (partial r = 0.18; P < 0.02) diastolic BP in participants with log HOMA-IR greater than or equal to the median were greater than those for relationships between urinary Na(+)/K(+) and 24-hour (partial r = -0.08; P = 0.29), day (partial r = -0.10; P < 0.22), and night (partial r = -0.06; P = 0.40) diastolic BP in participants with log HOMA-IR less than the median (comparisons of r values: P < 0.05). Insulin resistance may modify the relationship between salt intake, indexed by urinary Na(+)/K(+), and ambulatory BP in groups of African descent.

A combined qualitative and quantitative procedure for the chemical analysis of urinary calculi

PubMed Central

Hodgkinson, A.

1971-01-01

A better understanding of the physico-chemical principles underlying the formation of calculus has led to a need for more precise information on the chemical composition of stones. A combined qualitative and quantitative procedure for the chemical analysis of urinary calculi which is suitable for routine use is presented. The procedure involves five simple qualitative tests followed by the quantitative determination of calcium, magnesium, inorganic phosphate, and oxalate. These data are used to calculate the composition of the stone in terms of calcium oxalate, apatite, and magnesium ammonium phosphate. Analytical results and derived values for five representative types of calculi are presented. PMID:5551382

Plasma and Urinary Phenolic Profiles after Acute and Repetitive Intake of Wild Blueberry.

PubMed

Feliciano, Rodrigo P; Istas, Geoffrey; Heiss, Christian; Rodriguez-Mateos, Ana

2016-08-25

Recent studies have shown that blueberries may have cardiovascular and cognitive health benefits. In this work, we investigated the profile of plasma and urine (poly)phenol metabolites after acute and daily consumption of wild blueberries for 30 days in 18 healthy men. The inter-individual variability in plasma and urinary polyphenol levels was also investigated. Blood samples were collected at baseline and 2 h post-consumption on day 1 and day 30. Twenty-four-hour urine was also collected on both days. A total of 61 phenolic metabolites were quantified in plasma at baseline, of which 43 increased after acute or chronic consumption of blueberries over one month. Benzoic and catechol derivatives represented more than 80% of the changes in phenolic profile after 2 h consumption on day 1, whereas hippuric and benzoic derivatives were the major compounds that increased at 0 and 2 h on day 30, respectively. The total (poly)phenol urinary excretion remained unchanged after 30 days of wild blueberry intake. The inter-individual variability ranged between 40%-48% in plasma and 47%-54% in urine. Taken together, our results illustrate that blueberry (poly)phenols are absorbed and extensively metabolized by phase II enzymes and by the gut microbiota, leading to a whole array of metabolites that may be responsible for the beneficial effects observed after blueberry consumption.

A Food Debris-Like Component in the Urine Sediment From a Urostomy Pouch.

PubMed

Yamashita, Michiko; Hotta, Masaki; Yoshino, Kiyoshi; Hidaka, Yoh; Kimura, Tadashi

2017-05-01

Microscopic examination of urine sediment is a basic, common method of detecting diseases of the urinary tract. We experienced a case involving a patient who had developed a fever after undergoing a urinary-diversion operation. Results of the microscopic examination of the urine collected from the urostomy pouch of the patient showed a food debris-like component. Based on this finding, we suspected a fistula between the urinary and intestinal tracts. However, after performing an experiment to verify the results, we determined that no fistula was present. Instead, we discovered that the food debris-like component originated from the urostomy skin barrier. To our knowledge, ours is the first report in the literature to demonstrate that the urostomy skin barrier can dissolve and mimic food debris in urine sediment, leading to incorrect assumptions regarding the presence of fistulas. We believe that it is important to derive a correct diagnosis when an unfamiliar component is observed in urinary sediment. We further believe that the findings from this case are valuable to professionals who administer clinical treatment and perform laboratory testing. © American Society for Clinical Pathology, 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Are purines mediators of the anticonvulsant/neuroprotective effects of ketogenic diets?

PubMed Central

Masino, Susan A.; Geiger, Jonathan D.

2015-01-01

Abnormal neuronal signaling caused by metabolic changes characterizes several neurological disorders, and in some instances metabolic interventions provide therapeutic benefits. Indeed, altering metabolism either by fasting or by maintaining a low-carbohydrate (ketogenic) diet might reduce epileptic seizures and offer neuroprotection in part because the diet increases mitochondrial biogenesis and brain energy levels. Here we focus on a novel hypothesis that a ketogenic diet-induced change in energy metabolism increases levels of ATP and adenosine, purines that are critically involved in neuron–glia interactions, neuromodulation and synaptic plasticity. Enhancing brain bioenergetics (ATP) and increasing levels of adenosine, an endogenous anticonvulsant and neuroprotective molecule, might help with understanding and treating a variety of neurological disorders. PMID:18471903

Caffeine inhibition of aflatoxin production: mode of action.

PubMed Central

Buchanan, R L; Hoover, D G; Jones, S B

1983-01-01

Evaluation of caffeine and a number of related methylxanthines indicated that the ability of the compound to inhibit growth and aflatoxin production by Aspergillus parasiticus is highly specific and does not involve an inhibition of cyclic AMP phosphodiesterase. Supplementation of the culture medium with purine bases, nucleosides, and nucleotides suggested that the inhibition of fungal growth could be partially overcome by adenine or guanine but that the purines had little effect on the inhibition of aflatoxin production. Likewise, increasing the levels of trace minerals did not overcome the inhibition of toxin production. Electron microscopic evaluation of caffeine-treated and -untreated cultures indicated that the compound produced observable changes in the ultrastructure of the fungus. Images PMID:6316853

Cell-Based Therapies in Lower Urinary Tract Disorders.

PubMed

Gopinath, Chaitanya; Ponsaerts, Peter; Wyndaele, Jean Jacques

2015-01-01

Cell-based therapy for the bladder has its beginnings in the 1990s with the successful isolation and culture of bladder smooth muscle cells. Since then, several attempts have been made to artificially implant native cell types and stem cell-derived cells into damaged bladders in the form of single-cell injectables or as grafts seeded onto artificial extracellular matrix. We critically examined in the literature the types of cells and their probable role as an alternative to non-drug-based, non-bowel-based graft replacement therapy in disorders of the urinary bladder. The limitations and plausible improvements to these novel therapies have also been discussed, keeping in mind an ideal therapy that could suit most bladder abnormalities arising out of varied number of disorders. In conclusion, muscle-derived cell types have consistently proven to be a promising therapy to emerge in the coming decade. However, tissue-engineered constructs have yet to prove their success in preclinical and long-term clinical setting.

The relevance of the urinary concentration of ephedrines in anti-doping analysis: determination of pseudoephedrine, cathine, and ephedrine after administration of over-the-counter medicaments.

PubMed

Strano-Rossi, Sabina; Leone, Daniele; de la Torre, Xavier; Botrè, Francesco

2009-08-01

This article describes a method for the detection and quantitation of cathine, pseudoephedrine, ephedrine, and methylephedrine in urine, using their deuterated analogues as internal standards and derivatization to form the corresponding trimethylsilyl derivatives after a simple liquid-liquid extraction. The study was designed to evaluate whether the urinary cutoff values set by the World Anti-Doping Agency for the banned ephedrines (cathine >5 microg/mL, ephedrine and methylephedrine >10 microg/mL) can be exceeded after the normal self-administration of common over-the-counter medicaments containing nonbanned ephedrines. The present method, after validation, has been applied on real urine samples obtained from 9 healthy volunteers taking different doses of over-the-counter preparations containing ephedrines. Results obtained from excretion studies show high interindividual differences in the urinary concentrations of both pseudoephedrine and cathine, not dependent on body weight or sex nor, in some instances, on the administered dose. The same typical therapeutic dose of pseudoephedrine (60 mg) produced a urinary concentration of more than 5 microg/mL for cathine and of more than 100 microg/mL for pseudoephedrine in 2 of 9 subjects only. When a dose of 120 mg was administered, cathine concentration exceeded 5 microg/mL in 4 of 7 subject, and also concentrations of pseudoephedrine above 100 microg/mL. After administration of 5 x 120 mg of pseudoephedrine (120 mg administered every 7 days for 5 weeks) to one of the subjects exceeding the urinary threshold values, the urinary concentration of cathine and pseudoephedrine exceeded 5 microg/mL (peak concentration 14.8 microg/mL) and 100 microg/mL (peak concentration 275 microg/mL), respectively. When the same subject took 180 mg of pseudoephedrine, the urinary concentration values were below 5 microg/mL for ephedrine and 100 microg/mL for pseudoephedrine. In the case of ephedrine administration in a sustained-release formulation containing 12 mg of ephedrine, 2 of 3 subjects exceeded the urinary cutoff value of 10 microg/mL. The high interindividual variability is still significant even if the urinary concentration values are adjusted by specific gravity and/or creatinine. These results confirm a high interindividual variability in the urinary concentration of ephedrines after the administration of the same therapeutic dose of a preparation.

Impact of complications and bladder cancer stage on quality of life in patients with different types of urinary diversions.

PubMed

Prcic, Alden; Aganovic, Damir; Hadziosmanovic, Osman

2013-12-01

Determine correlation between complications and stage of the disease and their impact on quality of life in patients with different types of ileal urinary derivation after radical cystectomy, and upon estimation of acquired results, to suggest the most acceptable type of urinary diversion. In five year period a prospective clinical study was performed on 106 patients, to whom a radical cystectomy was performed due to bladder cancer. Patients were divided into two groups, 66 patients with ileal conduit derivation and 40 patients with orthotopic derivation, whereby in each group a comparison between reflux and anti-reflux technique of orthotopic bladder was made. All patients from both groups filled the Sickness Impact Profile score six months after the operation. All patients had CT urography or Intravenous urography performed, as well as standard laboratory, vitamin B12 blood values, in order to evaluate early (ileus or subileus, wound dehiscence, bladder fistula, rupture of orthotopic bladder, urine extravazation) and late complications (VUR, urethral stricture, ureter stenosis, metabolic acidosis, mineral dis-balance, hypovitaminosis of vitamin B12, increased resorption of bone calcium, urinary infection, kidney damage, relapse of primary disease), so as disease stage and it's impact on quality of life. From gained results we observe that each category of SIP score correlates with different rate of correlation with the type of operation, group, T, N, and R grade, except work category. Average value of SIP score rises depending on the type of operation and T stage. It is notable that there is no difference in T1 stage, no matter the type of operation. So the average value of SIP score in T1 stage for conduit was 20.3, for Abol-Enein and Ghoneim 17.25 and Hautmann 18.75 respectively. Average value of SIP score in T2 stage for conduit was 31, for Abol-Enein and Ghoneim 19.1 and Hautmann 17.8. Average value of SIP score in T3 stage for conduit was 38.03, for Abol-Enein and Ghoneim 18.75 and Hautmann 19.5. SIP score for T4 was present only in patients with conduit performed and average value od SIP score was 40.42. There is a high level of correlation of late complications and psychosocial and physical dimension with their parameters, while for an independent dimension of correlation is not significant. Early complications have insignificant correlation in all categories of SIP score. Upon analyzing quality of life and morbidity, significant advantage is given to orthotopic derivations, especially Hautmann derivation with Chimney modification, unless there are no absolute contraindications for performing this type of operation. Factors which mostly influence quality of life are cancer stage, type of derivation, late complications and patient age. SIP score, as a well validated questionnaire, are applicable in this kind of research.

Purine-benzimidazole hybrids: synthesis, single crystal determination and in vitro evaluation of antitumor activities.

PubMed

Sharma, Alka; Luxami, Vijay; Paul, Kamaldeep

2015-03-26

In an effort to identify novel compounds for the treatment of cancer, a diverse array of potential bioactive hybrid, purine-benzimidazole was synthesized in good yields through nucleophilic substitution at C6 position of purine ring with versatile cyclic amines at C2 position. The structures of newly prepared compounds were confirmed by IR, (1)H, (13)C NMR, mass spectroscopy and, in case of 19, by single crystal X-ray diffraction analysis. The newly synthesized compounds were evaluated against 60 human tumour cell lines at one dose concentration level. Compound 6 exhibited significant growth inhibition and was evaluated as 60 cell panel at five dose concentration levels. Compound 6 proved to be 1.25 fold more active than the positive control 5-FU, with GI50 value of 18.12 μM (MG-MID). Interaction of the compounds with Aurora-A enzyme involved in the process of propagation of cancer, has also been investigated. Compound 6 showed selectivity towards Aurora-A kinase inhibition with IC50 value of 0.0l μM. Molecular docking studies in the active binding site provided theoretical support for the experimental biological data acquired. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

GMP Synthase Is Required for Virulence Factor Production and Infection by Cryptococcus neoformans.

PubMed

Chitty, Jessica L; Tatzenko, Tayla L; Williams, Simon J; Koh, Y Q Andre E; Corfield, Elizabeth C; Butler, Mark S; Robertson, Avril A B; Cooper, Matthew A; Kappler, Ulrike; Kobe, Bostjan; Fraser, James A

2017-02-17

Over the last four decades the HIV pandemic and advances in medical treatments that also cause immunosuppression have produced an ever-growing cohort of individuals susceptible to opportunistic pathogens. Of these, AIDS patients are particularly vulnerable to infection by the encapsulated yeast Cryptococcus neoformans Most commonly found in the environment in purine-rich bird guano, C. neoformans experiences a drastic change in nutrient availability during host infection, ultimately disseminating to colonize the purine-poor central nervous system. Investigating the consequences of this challenge, we have characterized C. neoformans GMP synthase, the second enzyme in the guanylate branch of de novo purine biosynthesis. We show that in the absence of GMP synthase, C. neoformans becomes a guanine auxotroph, the production of key virulence factors is compromised, and the ability to infect nematodes and mice is abolished. Activity assays performed using recombinant protein unveiled differences in substrate binding between the C. neoformans and human enzymes, with structural insights into these kinetic differences acquired via homology modeling. Collectively, these data highlight the potential of GMP synthase to be exploited in the development of new therapeutic agents for the treatment of disseminated, life-threatening fungal infections. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Electrochemical evaluation of DNA methylation level based on the stoichiometric relationship between purine and pyrimidine bases.

PubMed

Wang, Po; Chen, Hanbin; Tian, Jiuying; Dai, Zong; Zou, Xiaoyong

2013-07-15

An efficient electrochemical approach for the evaluation of DNA methylation level was proposed according to the oxidation signal of DNA bases at an overoxidized polypyrrole (PPyox) directed multiwalled carbon nanotubes (MWNTs) film modified glassy carbon electrode (GCE). The PPyox/MWNTs/GCE exhibited remarkable electrocatalytic activities towards the oxidation of DNA bases due to the advantages of wide potential window, large effective surface area, and excellent antifouling property. As a result, all purine and pyrimidine bases of guanine (G), adenine (A), thymine (T), cytosine (C) and 5-methylcytosine (5-mC) exhibited well identified oxidation peaks at the PPyox/MWNTs/GCE. The direct potential resolution between 5-mC and C was obtained to be 180 mV, which was large enough for their signal recognition and accurate detection in mixture. In particular, the signal interference from T, a great challenge in exploring DNA methylation, was successfully eliminated by an innovative strategy, which was developed based on the stoichiometric relationship between purine and pyrimidine bases in DNA molecular structure. The proposed method was effectively applied to the rapid detection of DNA methylation status in real sample within 45 min with satisfactory results. Copyright © 2013 Elsevier B.V. All rights reserved.

Nicotinamide Riboside and Nicotinic Acid Riboside Salvage in Fungi and Mammals

PubMed Central

Belenky, Peter; Christensen, Kathryn C.; Gazzaniga, Francesca; Pletnev, Alexandre A.; Brenner, Charles

2009-01-01

NAD+ is a co-enzyme for hydride transfer enzymes and an essential substrate of ADP-ribose transfer enzymes and sirtuins, the type III protein lysine deacetylases related to yeast Sir2. Supplementation of yeast cells with nicotinamide riboside extends replicative lifespan and increases Sir2-dependent gene silencing by virtue of increasing net NAD+ synthesis. Nicotinamide riboside elevates NAD+ levels via the nicotinamide riboside kinase pathway and by a pathway initiated by splitting the nucleoside into a nicotinamide base followed by nicotinamide salvage. Genetic evidence has established that uridine hydrolase, purine nucleoside phosphorylase, and methylthioadenosine phosphorylase are required for Nrk-independent utilization of nicotinamide riboside in yeast. Here we show that mammalian purine nucleoside phosphorylase but not methylthioadenosine phosphorylase is responsible for mammalian nicotinamide riboside kinase-independent nicotinamide riboside utilization. We demonstrate that so-called uridine hydrolase is 100-fold more active as a nicotinamide riboside hydrolase than as a uridine hydrolase and that uridine hydrolase and mammalian purine nucleoside phosphorylase cleave nicotinic acid riboside, whereas the yeast phosphorylase has little activity on nicotinic acid riboside. Finally, we show that yeast nicotinic acid riboside utilization largely depends on uridine hydrolase and nicotinamide riboside kinase and that nicotinic acid riboside bioavailability is increased by ester modification. PMID:19001417

Investigations with methanobacteria and with evolution of the genetic code

NASA Technical Reports Server (NTRS)

Jukes, T. H.

1986-01-01

Mycoplasma capricolum was found by Osawa et al. to use UGA as the code of tryptophan and to contain 75% A + T in its DNA. This change could have been from evolutionary pressure to replace C + G by A + T. Numerous studies have been reported of evolution of proteins as measured by amino acid replacements that are observed when homologus proteins, such as hemoglobins from various vertebrates, are compared. These replacements result from nucleotide substitutions in amino acid codons in the corresponding genes. Simultaneously, silent nucleotide substitutions take place that can be studied when sequences of the genes are compared. These silent evolutionary changes take place mostly in third positions of codons. Two types of nucleotide substitutions are recognized: pyrimidine-pyrimidine and purine-purine interchanges (transitions) and pyriidine-purine interchanges (transversions). Silent transitions are favored when a corresponding transversion would produce an amino acid replacement. Conversely, silent transversions are favored by probability when transitions and transversions will both be silent. Extensive examples of these situations have been found in protein genes, and it is evident that transversions in silent positions predominate in family boxes in most of the examples studied. In associated research a streptomycete from cow manure was found to produce an extracellular enzyme capable of lysing the pseudomurein-contining methanogen Methanobacterium formicicum.

Cy3 and Cy5 dyes attached to oligonucleotide terminus stabilize DNA duplexes: predictive thermodynamic model.

PubMed

Moreira, Bernardo G; You, Yong; Owczarzy, Richard

2015-03-01

Cyanine dyes are important chemical modifications of oligonucleotides exhibiting intensive and stable fluorescence at visible light wavelengths. When Cy3 or Cy5 dye is attached to 5' end of a DNA duplex, the dye stacks on the terminal base pair and stabilizes the duplex. Using optical melting experiments, we have determined thermodynamic parameters that can predict the effects of the dyes on duplex stability quantitatively (ΔG°, Tm). Both Cy dyes enhance duplex formation by 1.2 kcal/mol on average, however, this Gibbs energy contribution is sequence-dependent. If the Cy5 is attached to a pyrimidine nucleotide of pyrimidine-purine base pair, the stabilization is larger compared to the attachment to a purine nucleotide. This is likely due to increased stacking interactions of the dye to the purine of the complementary strand. Dangling (unpaired) nucleotides at duplex terminus are also known to enhance duplex stability. Stabilization originated from the Cy dyes is significantly larger than the stabilization due to the presence of dangling nucleotides. If both the dangling base and Cy3 are present, their thermodynamic contributions are approximately additive. New thermodynamic parameters improve predictions of duplex folding, which will help design oligonucleotide sequences for biophysical, biological, engineering, and nanotechnology applications. Copyright © 2015. Published by Elsevier B.V.

Radiation-induced hydroxyl addition to purine molecules: EPR and ENDOR study of hypoxanthine hydrochloride monohydrate single crystals.

PubMed

Tokdemir, Sibel; Nelson, William H

2005-06-01

Three radical species were detected in an EPR/ENDOR study of X-irradiated hypoxanthine.HCl.H2O single crystals at room temperature: RI was identified as the product of net H addition to C8, RII was identified as the product of net H addition to C2, and RIII was identified as the product of OH addition to C8. The observed set of radicals was the same for room-temperature irradiation as for irradiation at 10 K followed by warming the crystals to room temperature; however, the C2 H-addition and C8 OH-addition radicals were not detectable after storage of the crystals for about 2 months at room temperature. Use of selectively deuterated crystals permitted unique assignment of the observed hyperfine couplings, and results of density functional theory calculations on each of the radical structures were consistent with the experimental results. Comparison of these experimental results with others from previous crystal-based systems and model system computations provides insight into the mechanisms by which the biologically important purine C8 hydroxyl addition products are formed. The evidence from solid systems supports the mechanism of net water addition to one-electron oxidized purine bases and demonstrates the importance of a facial approach between the reactants.

Expression for caffeine biosynthesis and related enzymes in Camellia sinensis.

PubMed

Kato, Misako; Kitao, Naoko; Ishida, Mariko; Morimoto, Hanayo; Irino, Fumi; Mizuno, Kouichi

2010-01-01

Caffeine (1,3,7-trimethylxanthine) is a purine alkaloid that is present in high concentrations in the tea plant Camellia sinensis. Caffeine synthase (CS, EC 2.1.1.160) catalyzes the S-adenosyl-L-methionine-dependent N-3- and N-1-methylation of the purine base to form caffeine, the last step in the purine alkaloid biosynthetic pathway. We studied the expression profile of the tea caffeine synthase (TCS) gene in developing leaves and flowers by means of northern blot analysis, and compared it with those of phenylalanine ammonia lyase (PAL, EC 4.3.1.5), chalcone synthase (CHS, EC 2.3.1.74), and S-adenosyl-L-methionine synthase (SAMS, EC 2.5.1.6). The amount of TCS transcripts was highest in young leaves and declined markedly during leaf development, whereas it remained constant throughout the development of the flower. Environmental stresses other than heavy metal stress and plant hormone treatments had no effect on the expression of TCS genes, unlike the other three genes. Drought stress suppressed TCS gene expression in leaves, and the expression pattern mirrored that of the dehydrin gene. The amounts of TCS transcripts increased slightly on supply of a nitrogen source. We discuss the regulation of TCS gene expression.

Gene set analysis of purine and pyrimidine antimetabolites cancer therapies.

PubMed

Fridley, Brooke L; Batzler, Anthony; Li, Liang; Li, Fang; Matimba, Alice; Jenkins, Gregory D; Ji, Yuan; Wang, Liewei; Weinshilboum, Richard M

2011-11-01

Responses to therapies, either with regard to toxicities or efficacy, are expected to involve complex relationships of gene products within the same molecular pathway or functional gene set. Therefore, pathways or gene sets, as opposed to single genes, may better reflect the true underlying biology and may be more appropriate units for analysis of pharmacogenomic studies. Application of such methods to pharmacogenomic studies may enable the detection of more subtle effects of multiple genes in the same pathway that may be missed by assessing each gene individually. A gene set analysis of 3821 gene sets is presented assessing the association between basal messenger RNA expression and drug cytotoxicity using ethnically defined human lymphoblastoid cell lines for two classes of drugs: pyrimidines [gemcitabine (dFdC) and arabinoside] and purines [6-thioguanine and 6-mercaptopurine]. The gene set nucleoside-diphosphatase activity was found to be significantly associated with both dFdC and arabinoside, whereas gene set γ-aminobutyric acid catabolic process was associated with dFdC and 6-thioguanine. These gene sets were significantly associated with the phenotype even after adjusting for multiple testing. In addition, five associated gene sets were found in common between the pyrimidines and two gene sets for the purines (3',5'-cyclic-AMP phosphodiesterase activity and γ-aminobutyric acid catabolic process) with a P value of less than 0.0001. Functional validation was attempted with four genes each in gene sets for thiopurine and pyrimidine antimetabolites. All four genes selected from the pyrimidine gene sets (PSME3, CANT1, ENTPD6, ADRM1) were validated, but only one (PDE4D) was validated for the thiopurine gene sets. In summary, results from the gene set analysis of pyrimidine and purine therapies, used often in the treatment of various cancers, provide novel insight into the relationship between genomic variation and drug response.

Poly-l-cysteine/electrospun copper oxide nanofibers-zinc oxide nanoparticles nanocomposite as sensing element of an electrochemical sensor for simultaneous determination of adenine and guanine in biological samples and evaluation of damage to dsDNA and DNA purine bases by UV radiation.

PubMed

Arvand, Majid; Sayyar Ardaki, Masoomeh

2017-09-15

A new nanocomposite film constructed of poly-l-cysteine/zinc oxide nanoparticles-electrospun copper oxide nanofibers (PLC/ZnO-NPs-CuO-NFs) was prepared on the surface of the graphite electrode (GE). The novel electrode was successfully applied for the simultaneous determination of guanine (G) and adenine (A), two of the most important components of DNA and RNA. The PLC/ZnO-NPs-CuO-NFs/GE enhanced the anodic peak currents of the purine bases conspicuously and could determine them sensitively and separately in 0.1 M phosphate buffer solution at the physiological pH (7.0). The synthesized nanofibers, nanoparticles and nanocomposite were characterized by different methods such as Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDS). Under the optimum operating conditions, linear calibration curves were obtained in the range of 0.05-6.78 and 0.01-3.87 μM with a detection limit of 12.48 and 1.25 nM for G and A, respectively. The proposed method was applied to quantify A and G in three different DNA samples with satisfactory results. In addition, damage to human blood double-stranded DNA (dsDNA) and DNA purine bases (liberated in previously hydrolyzed human blood dsDNA) caused by UV-C and UV-B were evaluated. The results demonstrated that the proposed biosensing platform not only provides a novel and sensitive approach to detecting DNA damage, but also can be used for simultaneous determination of purine bases and major products of DNA oxidative damage. Copyright © 2017 Elsevier B.V. All rights reserved.

Heterogeneity and dynamics of the ligand recognition mode in purine-sensing riboswitches.

PubMed

Jain, Niyati; Zhao, Liang; Liu, John D; Xia, Tianbing

2010-05-04

High-resolution crystal structures and biophysical analyses of purine-sensing riboswitches have revealed that a network of hydrogen bonding interactions appear to be largey responsible for discrimination of cognate ligands against structurally related compounds. Here we report that by using femtosecond time-resolved fluorescence spectroscopy to capture the ultrafast decay dynamics of the 2-aminopurine base as the ligand, we have detected the presence of multiple conformations of the ligand within the binding pockets of one guanine-sensing and two adenine-sensing riboswitches. All three riboswitches have similar conformational distributions of the ligand-bound state. The known crystal structures represent the global minimum that accounts for 50-60% of the population, where there is no significant stacking interaction between the ligand and bases of the binding pocket, but the hydrogen-bonding cage collectively provides an electronic environment that promotes an ultrafast ( approximately 1 ps) charge transfer pathway. The ligand also samples multiple conformations in which it significantly stacks with either the adenine or the uracil bases of the A21-U75 and A52-U22 base pairs that form the ceiling and floor of the binding pocket, respectively, but favors the larger adenine bases. These alternative conformations with well-defined base stacking interactions are approximately 1-1.5 kcal/mol higher in DeltaG degrees than the global minimum and have distinct charge transfer dynamics within the picosecond to nanosecond time regime. Inside the pocket, the purine ligand undergoes dynamic motion on the low nanosecond time scale, sampling the multiple conformations based on time-resolved anisotropy decay dynamics. These results allowed a description of the energy landscape of the bound ligand with intricate details and demonstrated the elastic nature of the ligand recognition mode by the purine-sensing riboswitches, where there is a dynamic balance between hydrogen bonding and base stacking interactions, yielding the high affinity and specificity by the aptamer domain.

Clay catalysis of oligonucleotide formation: kinetics of the reaction of the 5'-phosphorimidazolides of nucleotides with the non-basic heterocycles uracil and hypoxanthine

NASA Technical Reports Server (NTRS)

Kawamura, K.; Ferris, J. P.

1999-01-01

The montmorillonite clay catalyzed condensation of activated monocleotides to oligomers of RNA is a possible first step in the formation of the proposed RNA world. The rate constants for the condensation of the phosphorimidazolide of adenosine were measured previously and these studies have been extended to the phosphorimidazolides of inosine and uridine in the present work to determine of substitution of neutral heterocycles for the basic adenine ring changes the reaction rate or regioselectivity. The oligomerization reactions of the 5'-phosphoromidazolides of uridine (ImpU) and inosine (ImpI) on montmorillonite yield oligo(U)s and oligo(I)s as long as heptamers. The rate constants for oligonucleotide formation were determined by measuring the rates of formation of the oligomers by HPLC. Both the apparent rate constants in the reaction mixture and the rate constants on the clay surface were calculated using the partition coefficients of the oligomers between the aqueous and clay phases. The rate constants for trimer formation are much greater than those dimer synthesis but there was little difference in the rate constants for the formation of trimers and higher oligomers. The overall rates of oligomerization of the phosphorimidazolides of purine and pyrimidine nucleosides in the presence of montmorillonite clay are the same suggesting that RNA formed on the primitive Earth could have contained a variety of heterocyclic bases. The rate constants for oligomerization of pyrimidine nucleotides on the clay surface are significantly higher than those of purine nucleotides since the pyrimidine nucleotides bind less strongly to the clay than do the purine nucleotides. The differences in the binding is probably due to Van der Waals interactions between the purine bases and the clay surface. Differences in the basicity of the heterocyclic ring in the nucleotide have little effect on the oligomerization process.

Deubiquitylation of Protein Cargo Is Not an Essential Step in Exosome Formation*

PubMed Central

Huebner, Alyssa R.; Cheng, Lei; Somparn, Poorichaya; Knepper, Mark A.; Fenton, Robert A.; Pisitkun, Trairak

2016-01-01

Exosomes, derived from multivesicular bodies (MVBs), contain proteins and genetic materials from their cell of origin and are secreted from various cells types, including kidney epithelial cells. In general, it is thought that protein cargo is ubiquitylated but that ubiquitin is cleaved by specific deubiquitylases during the process of cargo incorporation into MVBs. Here, we provide direct evidence that, in vivo, deubiquitylation is not essential. Ubiquitin was detected within human MVBs and urinary exosomes by electron microscopy. Of the >6000 proteins identified in human urinary exosomes was mass spectrometry, 15% were ubiquitylated with various topologies (Lys63>Lys48> Lys11>Lys6>Lys29>Lys33>Lys27). A significant preference for basic amino acids upstream of ubiquitylation sites suggests specific ubiquitylation motifs. The current studies demonstrate that, in vivo, deubiquitylation of proteins is not necessary for their incorporation into MVBs and highlight that urinary exosomes are an enriched source for studying ubiquitin modifications in physiological or disease states. PMID:26884507

An Ultrahigh-Performance Liquid Chromatography-Time-of-Flight Mass Spectrometry Metabolomic Approach to Studying the Impact of Moderate Red-Wine Consumption on Urinary Metabolome.

PubMed

Esteban-Fernández, Adelaida; Ibañez, Clara; Simó, Carolina; Bartolomé, Begoña; Moreno-Arribas, M Victoria

2018-04-06

Moderate red-wine consumption has been widely described to exert several benefits in human health. This is mainly due to its unique content of bioactive polyphenols, which suffer several modifications along their pass through the digestive system, including microbial transformation in the colon and phase-II metabolism, until they are finally excreted in urine and feces. To determine the impact of moderate wine consumption in the overall urinary metabolome of healthy volunteers ( n = 41), samples from a red-wine interventional study (250 mL/day, 28 days) were investigated. Urine (24 h) was collected before and after intervention and analyzed by an untargeted ultrahigh-performance liquid chromatography-time-of-flight mass spectrometry metabolomics approach. 94 compounds linked to wine consumption, including specific wine components (tartaric acid), microbial-derived phenolic metabolites (5-(dihydroxyphenyl)-γ-valerolactones and 4-hydroxyl-5-(phenyl)-valeric acids), and endogenous compounds were identified. Also, some relationships between parallel fecal and urinary metabolomes are discussed.

A small and efficient dimerization/packaging signal of rat VL30 RNA and its use in murine leukemia virus-VL30-derived vectors for gene transfer.

PubMed

Torrent, C; Gabus, C; Darlix, J L

1994-02-01

Retroviral genomes consist of two identical RNA molecules associated at their 5' ends by the dimer linkage structure located in the packaging element (Psi or E) necessary for RNA dimerization in vitro and packaging in vivo. In murine leukemia virus (MLV)-derived vectors designed for gene transfer, the Psi + sequence of 600 nucleotides directs the packaging of recombinant RNAs into MLV virions produced by helper cells. By using in vitro RNA dimerization as a screening system, a sequence of rat VL30 RNA located next to the 5' end of the Harvey mouse sarcoma virus genome and as small as 67 nucleotides was found to form stable dimeric RNA. In addition, a purine-rich sequence located at the 5' end of this VL30 RNA seems to be critical for RNA dimerization. When this VL30 element was extended by 107 nucleotides at its 3' end and inserted into an MLV-derived vector lacking MLV Psi +, it directed the efficient encapsidation of recombinant RNAs into MLV virions. Because this VL30 packaging signal is smaller and more efficient in packaging recombinant RNAs than the MLV Psi + and does not contain gag or glyco-gag coding sequences, its use in MLV-derived vectors should render even more unlikely recombinations which could generate replication-competent viruses. Therefore, utilization of the rat VL30 packaging sequence should improve the biological safety of MLV vectors for human gene transfer.

Estimating 24-Hour Urinary Sodium Excretion From Casual Urinary Sodium Concentrations in Western Populations

PubMed Central

Brown, Ian J.; Dyer, Alan R.; Chan, Queenie; Cogswell, Mary E.; Ueshima, Hirotsugu; Stamler, Jeremiah; Elliott, Paul

2013-01-01

High intakes of dietary sodium are associated with elevated blood pressure levels and an increased risk of cardiovascular disease. National and international guidelines recommend reduced sodium intake in the general population, which necessitates population-wide surveillance. We assessed the utility of casual (spot) urine specimens in estimating 24-hour urinary sodium excretion as a marker of sodium intake in the International Cooperative Study on Salt, Other Factors, and Blood Pressure. There were 5,693 participants recruited in 1984–1987 at the ages of 20–59 years from 29 North American and European samples. Participants were randomly assigned to test or validation data sets. Equations derived from casual urinary sodium concentration and other variables in the test data were applied to the validation data set. Correlations between observed and estimated 24-hour sodium excretion were 0.50 for individual men and 0.51 for individual women; the values were 0.79 and 0.71, respectively, for population samples. Bias in mean values (observed minus estimated) was small; for men and women, the values were −1.6 mmol per 24 hours and 2.3 mmol per 24 hours, respectively, at the individual level and −1.8 mmol per 24 hours and 2.2 mmol per 24 hours, respectively, at the population level. Proportions of individuals with urinary 24-hour sodium excretion above the recommended levels were slightly overestimated by the models. Casual urine specimens may be a useful, low-burden, low-cost alternative to 24-hour urine collections for estimation of population sodium intakes; ongoing calibration with study-specific 24-hour urinary collections is recommended to increase validity. PMID:23673246

Metabolism of Primed, Constant Infusions of [1,2-13C2] Glycine and [1-13C1] Phenylalanine to Urinary Oxalate

PubMed Central

Knight, John; Assimos, Dean G.; Callahan, Michael F.; Holmes, Ross P.

2010-01-01

Objective Experiments in humans and rodents using oral doses of glycine and phenylalanine have suggested that the metabolism of these amino acids contributes to urinary oxalate excretion. To better define this contribution we have examined the primed, constant infusion of [1-13C1] phenylalanine and [1,2-13C2] glycine in the post-absorptive state in healthy adults. Materials/Methods Subjects were infused for 5 hours, collected hourly urines and had blood drawn every 30 minutes. Ion chromatography/mass spectrometry was used to measure [13C] enrichment in urinary oxalate, glycolate and hippurate, and the enrichment of 13C-amino acids in plasma samples was measured by gas chromatography/mass spectrometry. Results Following infusion with either 6 µmoles/kg/hr [1-13C1] phenylalanine or 6 µmoles/kg/hr [1,2-13C2] glycine, no isotopic glycolate or oxalate was detected in urine. Based on the limits of detection of our ion chromatography/mass spectroscopy method, these data indicate that < 0.7% of the urinary oxalate could be derived from phenylalanine catabolism and < 5% from glycine catabolism. Infusions with high levels of [1,2-13C2] glycine, 60 µmoles/kg/hr, increased mean plasma glycine by 29% and the whole body flux of glycine by 72%. Under these conditions glycine contributed 16.0 ± 1.6% and 16.6 ± 3.2% to urinary oxalate and glycolate excretion, respectively. Experiments using cultured hepatoma cells demonstrated that only at supra-physiological levels (>1mM) did glycine and phenylalanine metabolism increase oxalate synthesis. Conclusions These data suggest glycine and phenylalanine metabolism make only minor contributions to oxalate synthesis and urinary oxalate excretion. PMID:21036374

Natural Products as New Treatment Options for Trichomoniasis: A Molecular Docking Investigation.

PubMed

Setzer, Mary Snow; Byler, Kendall G; Ogungbe, Ifedayo Victor; Setzer, William N

2017-01-27

Trichomoniasis, caused by the parasitic protozoan Trichomonas vaginalis, is the most common non-viral sexually-transmitted disease, and there can be severe complications from trichomoniasis. Antibiotic resistance in T. vaginalis is increasing, but there are currently no alternatives treatment options. There is a need to discover and develop new chemotherapeutic alternatives. Plant-derived natural products have long served as sources for new medicinal agents, as well as new leads for drug discovery and development. In this work, we have carried out an in silico screening of 952 antiprotozoal phytochemicals with specific protein drug targets of T. vaginalis. A total of 42 compounds showed remarkable docking properties to T. vaginalis methionine gamma-lyase (TvMGL) and to T. vaginalis purine nucleoside phosphorylase (TvPNP). The most promising ligands were polyphenolic compounds, and several of these showed docking properties superior to either co-crystallized ligands or synthetic enzyme inhibitors.

Observing interactions between DNA bases using ion dip spectroscopy.

NASA Astrophysics Data System (ADS)

Vries Mattanjah, De

2002-03-01

We investigate biomolecular building blocks and their clusters with each other and with water on a single molecular level. The motivation is the need to distinguish between intrinsic molecular properties and those that result from the biological environment. This is achieved by a combination of laser desorption and jet cooling, applied to aromatic amino acids, small peptides containing those, purine bases and nucleosides. This approach is coupled with a number of gas phase laser spectroscopic techniques. We will present results for DNA bases guanine, adenine, cytosine, and their derivatives, for which we obtained tautomer selected vibronic spectra. Capitalizing on these results we use these bases as chromophores to study interactions in single base pairs, obtained by formation of clusters of laser desorbed bases in a supersonic beam. For analysis we employ both UV/UV and IR/UV ion-dip spectroscopy, the results of which we compare with ab initio calculations.

Neurotrophin/receptor expression in urinary bladder of mice with overexpression of NGF in urothelium.

PubMed

Girard, Beatrice M; Malley, Susan E; Vizzard, Margaret A

2011-02-01

Urothelium-specific overexpression of nerve growth factor (NGF) in the urinary bladder of transgenic mice stimulates neuronal sprouting in the urinary bladder, produces increased voiding frequency, and results in increased referred somatic hypersensitivity. Additional NGF-mediated pleiotropic changes might contribute to the increased voiding frequency and pelvic hypersensitivity observed in these transgenic mice, such as modulation of other growth factor/receptor systems. Chronic overexpression of NGF in the urothelium was achieved through the use of a highly urothelium-specific uroplakin II promoter. In the present study, we examined NGF, brain-derived neurotrophic factor (BDNF), and associated receptor [p75(NTR), tyrosine kinase (Trk)A, TrkB] transcript and protein expression in urothelium and detrusor smooth muscle of NGF-overexpressing (OE) and littermate wild-type mice, using real-time quantitative reverse transcription-polymerase chain reaction, ELISAs, and semiquantitation of immunohistochemistry. We focused on these growth factor/receptors given the established roles of NGF/TrkA, NGF/p75(NTR), and BDNF/TrkB systems in bladder function. Increased voiding frequency in NGF-OE mice was confirmed by examining urination patterns. BDNF, TrkA, and TrkB protein expression was significantly (P ≤ 0.01) reduced and p75(NTR) protein expression was significantly (P ≤ 0.01) increased in urinary bladder of NGF-OE mice. The NGF-OE-induced changes in neurotrophic factor/receptor expression in urinary bladder may represent compensatory changes to reduce voiding frequency in the NGF-OE mouse.

C–C Cross-Coupling Reactions of O6-Alkyl-2-Haloinosine Derivatives and a One-Pot Cross-Coupling/O6-Deprotection Procedure

PubMed Central

Gurram, Venkateshwarlu; Pottabathini, Narender; Garlapati, Ramesh; Chaudhary, Avinash B.; Patro, Balaram; Lakshman, Mahesh K.

2012-01-01

Reaction conditions for the C–C cross-coupling of O6-alkyl-2-bromo- and 2-chloroinosine derivatives with aryl-, hetaryl-, and alkylboronic acids were studied. Optimization experiments with silyl-protected 2-bromo-O6-methylinosine led to the identification of [PdCl2(dcpf)]/K3PO4 in 1,4-dioxane as the best condition for these reactions (dcpf = 1,1’-bis(dicyclohexylphosphino)ferrocene). Attempted O6-demethylation, as well as the replacement of the C-6 methoxy group by amines, was unsuccessful, which led to the consideration of Pd-cleavable groups such that C–C cross-coupling and O6-deprotection could be accomplished in a single step. Thus, inosine 2-chloro-O6-allylinosine was chosen as the substrate and, after re-evaluation of the cross-coupling conditions with 2-chloro-O6-methylinosine as a model substrate, one-step C–C cross-coupling/deprotection reactions were performed with the O6-allyl analogue. These reactions are the first such examples of a one-pot procedure for the modification and deprotection of purine nucleosides under C–C cross-coupling conditions. PMID:22570232

Major urinary metabolites of 6-keto-prostaglandin F2α in mice[S

PubMed Central

Kuklev, Dmitry V.; Hankin, Joseph A.; Uhlson, Charis L.; Hong, Yu H.; Murphy, Robert C.; Smith, William L.

2013-01-01

Western diets are enriched in omega-6 vs. omega-3 fatty acids, and a shift in this balance toward omega-3 fatty acids may have health benefits. There is limited information about the catabolism of 3-series prostaglandins (PG) formed from eicosapentaenoic acid (EPA), a fish oil omega-3 fatty acid that becomes elevated in tissues following fish oil consumption. Quantification of appropriate urinary 3-series PG metabolites could be used for noninvasive measurement of omega-3 fatty acid tone. Here we describe the preparation of tritium- and deuterium-labeled 6-keto-PGF2α and their use in identifying urinary metabolites in mice using LC-MS/MS. The major 6-keto-PGF2α urinary metabolites included dinor-6-keto-PGF2α (∼10%) and dinor-13,14-dihydro-6,15-diketo-PGF1α (∼10%). These metabolites can arise only from the enzymatic conversion of EPA to the 3-series PGH endoperoxide by cyclooxygenases, then PGI3 by prostacyclin synthase and, finally, nonenzymatic hydrolysis to 6-keto-PGF2α. The 6-keto-PGF derivatives are not formed by free radical mechanisms that generate isoprostanes, and thus, these metabolites provide an unbiased marker for utilization of EPA by cyclooxygenases. PMID:23644380

Stomach cancer in 67 Chinese counties: evidence of interaction between salt consumption and helicobacter pylori infection.

PubMed

Wang, Xiaoqin; Terry, Paul; Yan, Hong

2008-01-01

To examine the interaction between salt-intake and helicobacter pylori (H. pylori) infection in the development of stomach cancer in an ecological study of 67 Chinese rural counties. Stomach cancer mortality data of 67 counties were derived from a national survey conducted in China between 1986 and 1988. Information regarding the prevalence of H. pylori infection and urinary sodium excretion were collected from the same individuals during a subsequent dietary survey in 1989. In these 67 counties, H. pylori prevalence and urinary sodium were correlated with stomach cancer mortality, with r=0.31 (p=0.01) and r=0.28 (p=0.03), respectively. After stratification, the significant correlation between H. pylori prevalence and stomach cancer mortality only existed in counties with high levels (> or =5.0 mg/mg creatinine/12-hour) of urinary sodium (r=0.5; p=0.002). Similarly, the significant correlation between urinary sodium and stomach cancer mortality was only presented in counties with high (> or =71.6%) H. pylori prevalence (r=0.4; p=0.017). Multivariate regression analysis showed results consistent with the correlation analysis. These findings suggest that there may be an interaction between high salt consumption and H .pylori infection in the development of stomach cancer. Corroborating data from epidemiological, clinical, and experimental studies are needed.

Bovine papillomavirus type 2 infection and a series of mesenchymal tumors of the urinary bladder in cattle.

PubMed

Martano, Manuela; Roperto, Franco; Stocco, Rita de Cassia; Russo, Valeria; Borzacchiello, Giuseppe; Paciello, Orlando; Iovane, Valentina; Leonardi, Leonardo; Maiolino, Paola; Restucci, Brunella; Papparella, Serenella; Roperto, Sante

2013-01-01

This report describes the histopathology of two hundred and fifty-three mesenchymal tumors of the urinary bladder in cattle grazing on lands rich in bracken fern. Approximately 80% were hemangiomas and angiosarcomas. Hemangioma (capillary, cavernous, and large vessels) was the most frequent mesenchymal tumor and was more common than angiosarcoma. Although the appearance of endothelial cells can vary remarkably, epithelioid angiosarcomas, often containing multinucleated cells, were the most frequent malignant vascular tumors. Hemangiopericytoma and tumors of muscle and soft connective tissue origin, alone and/or in association with tumor-like lesions, were less frequently seen. Furthermore, forty-five cases of intravascular papillary endothelial hyperplasia (IPEH), a lesion not previously reported in the urinary bladder of cattle, were also described. Bovine papillomavirus type-2 DNA was amplified in tumor samples. Forty vascular tumors were investigated by dual-labeling immunofluorescence, and, for the first time, a coexpression of E5 and platelet-derived growth factor β receptor (PDGF β R) was shown to occur. The results show that the BPV-2 E5 oncoprotein binds to the activated form of the PDGF β receptor thus playing an important role in mesenchymal as well as epithelial carcinogenesis of the urinary bladder. Furthermore, these findings demonstrate that BPV-2 infects both epithelial and mesenchymal cells.

Bovine Papillomavirus Type 2 Infection and a Series of Mesenchymal Tumors of the Urinary Bladder in Cattle

PubMed Central

Martano, Manuela; Roperto, Franco; Russo, Valeria; Borzacchiello, Giuseppe; Paciello, Orlando; Iovane, Valentina; Leonardi, Leonardo; Maiolino, Paola; Restucci, Brunella; Papparella, Serenella; Roperto, Sante

2013-01-01

This report describes the histopathology of two hundred and fifty-three mesenchymal tumors of the urinary bladder in cattle grazing on lands rich in bracken fern. Approximately 80% were hemangiomas and angiosarcomas. Hemangioma (capillary, cavernous, and large vessels) was the most frequent mesenchymal tumor and was more common than angiosarcoma. Although the appearance of endothelial cells can vary remarkably, epithelioid angiosarcomas, often containing multinucleated cells, were the most frequent malignant vascular tumors. Hemangiopericytoma and tumors of muscle and soft connective tissue origin, alone and/or in association with tumor-like lesions, were less frequently seen. Furthermore, forty-five cases of intravascular papillary endothelial hyperplasia (IPEH), a lesion not previously reported in the urinary bladder of cattle, were also described. Bovine papillomavirus type-2 DNA was amplified in tumor samples. Forty vascular tumors were investigated by dual-labeling immunofluorescence, and, for the first time, a coexpression of E5 and platelet-derived growth factor β receptor (PDGFβR) was shown to occur. The results show that the BPV-2 E5 oncoprotein binds to the activated form of the PDGFβ receptor thus playing an important role in mesenchymal as well as epithelial carcinogenesis of the urinary bladder. Furthermore, these findings demonstrate that BPV-2 infects both epithelial and mesenchymal cells. PMID:23862156

Exploratory urinary metabolomics of type 1 leprosy reactions.

PubMed

Mayboroda, Oleg A; van Hooij, Anouk; Derks, Rico; van den Eeden, Susan J F; Dijkman, Karin; Khadge, Saraswoti; Thapa, Pratibha; Kunwar, Chhatra B; Hagge, Deanna A; Geluk, Annemieke

2016-04-01

Leprosy is an infectious disease caused by Mycobacterium leprae that affects the skin and nerves. Although curable with multidrug therapy, leprosy is complicated by acute inflammatory episodes called reactions, which are the major causes of irreversible neuropathy in leprosy that occur before, during, and even after treatment. Early diagnosis and prompt treatment of reactions reduces the risk of permanent disability. This exploratory study investigated whether urinary metabolic profiles could be identified that correlate with early signs of reversal reactions (RR). A prospective cohort of leprosy patients with and without reactions and endemic controls was recruited in Nepal. Urine-derived metabolic profiles were measured longitudinally. Thus, a conventional area of biomarker identification for leprosy was extended to non-invasive urine testing. It was found that the urinary metabolome could be used to discriminate endemic controls from untreated patients with mycobacterial disease. Moreover, metabolic signatures in the urine of patients developing RR were clearly different before RR onset compared to those at RR diagnosis. This study indicates that urinary metabolic profiles are promising host biomarkers for the detection of intra-individual changes during acute inflammation in leprosy and could contribute to early treatment and prevention of tissue damage. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Genetics Home Reference: purine nucleoside phosphorylase deficiency

MedlinePlus

... 70 affected individuals have been identified. This disorder accounts for approximately 4 percent of all SCID cases. Related Information What information about a genetic condition can statistics ...

Diagnosis, treatment, and prevention of gout.

PubMed

Hainer, Barry L; Matheson, Eric; Wilkes, R Travis

2014-12-15

Gout is characterized by painful joint inflammation, most commonly in the first metatarsophalangeal joint, resulting from precipitation of monosodium urate crystals in a joint space. Gout is typically diagnosed using clinical criteria from the American College of Rheumatology. Diagnosis may be confirmed by identification of monosodium urate crystals in synovial fluid of the affected joint. Acute gout may be treated with nonsteroidal anti-inflammatory drugs, corticosteroids, or colchicine. To reduce the likelihood of recurrent flares, patients should limit their consumption of certain purine-rich foods (e.g., organ meats, shellfish) and avoid alcoholic drinks (especially beer) and beverages sweetened with high-fructose corn syrup. Consumption of vegetables and low-fat or nonfat dairy products should be encouraged. The use of loop and thiazide diuretics can increase uric acid levels, whereas the use of the angiotensin receptor blocker losartan increases urinary excretion of uric acid. Reduction of uric acid levels is key to avoiding gout flares. Allopurinol and febuxostat are first-line medications for the prevention of recurrent gout, and colchicine and/or probenecid are reserved for patients who cannot tolerate first-line agents or in whom first-line agents are ineffective. Patients receiving urate-lowering medications should be treated concurrently with nonsteroidal anti-inflammatory drugs, colchicine, or low-dose corticosteroids to prevent flares. Treatment should continue for at least three months after uric acid levels fall below the target goal in those without tophi, and for six months in those with a history of tophi.

Global Metabolomic Identification of Long-Term Dose-Dependent Urinary Biomarkers in Nonhuman Primates Exposed to Ionizing Radiation.

PubMed

Pannkuk, Evan L; Laiakis, Evagelia C; Authier, Simon; Wong, Karen; Fornace, Albert J

2015-08-01

Due to concerns surrounding potential large-scale radiological events, there is a need to determine robust radiation signatures for the rapid identification of exposed individuals, which can then be used to guide the development of compact field deployable instruments to assess individual dose. Metabolomics provides a technology to process easily accessible biofluids and determine rigorous quantitative radiation biomarkers with mass spectrometry (MS) platforms. While multiple studies have utilized murine models to determine radiation biomarkers, limited studies have profiled nonhuman primate (NHP) metabolic radiation signatures. In addition, these studies have concentrated on short-term biomarkers (i.e., <72 h). The current study addresses the need for biomarkers beyond 72 h using a NHP model. Urine samples were collected at 7 days postirradiation (2, 4, 6, 7 and 10 Gy) and processed with ultra-performance liquid chromatography (UPLC) quadrupole time-of-flight (QTOF) MS, acquiring global metabolomic radiation signatures. Multivariate data analysis revealed clear separation between control and irradiated groups. Thirteen biomarkers exhibiting a dose response were validated with tandem MS. There was significantly higher excretion of l-carnitine, l-acetylcarnitine, xanthine and xanthosine in males versus females. Metabolites validated in this study suggest perturbation of several pathways including fatty acid β oxidation, tryptophan metabolism, purine catabolism, taurine metabolism and steroid hormone biosynthesis. In this novel study we detected long-term biomarkers in a NHP model after exposure to radiation and demonstrate differences between sexes using UPLC-QTOF-MS-based metabolomics technology.

Short-term toxicity assessments of an antibiotic metabolite in Wistar rats and its metabonomics analysis by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry.

PubMed

Han, Hongxing; Xiao, Hailong; Lu, Zhenmei

2016-02-15

4-Epi-oxytetracycline (4-EOTC), one of main oxytetracycline (OTC) metabolites, can be commonly detected in food and environment. The toxicity and effects of OTC on animals have been well characterized; however, its metabolites have never been studied systemically. This study aims to investigate 15-day oral dose toxicity and urine metabonomics changes of 4-EOTC after repeated administration in Wistar rats at daily doses of 0.5, 5.0 and 50.0mg/kg bw (bodyweight). Hematology and clinical chemistry parameters, including white blood cell count, red blood cell count, total protein, globulin and albumin/globulin, were obviously altered in rats of 5.0 and 50.0mg/kg bw. Histopathology changes of kidney and liver tissues were also observed in high-dose groups. Urinary metabolites from all groups were analyzed using ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). Seventeen metabolites contributing to the clusters were identified as potential biomarkers from multivariate analysis, including aminoadipic acid, 6-phosphogluconate, sebacic acid, pipecolic acid, etc. The significant changes of these biomarkers demonstrated metabonomic variations in treated rats, especially lysine and purine metabolism. For the first time in this paper, we combined the results of toxicity and metabonomics induced by 4-EOTC for the serious reconsideration of the safety and potential risks of antibiotics and its degradation metabolites. Copyright © 2016 Elsevier Inc. All rights reserved.

Deriving Biomonitoring Equivalents for selected E- and P-series glycol ethers for public health risk assessment.

PubMed

Poet, Torka; Ball, Nicholas; Hays, Sean M

2016-01-01

Glycol ethers are a widely used class of solvents that may lead to both workplace and general population exposures. Biomonitoring studies are available that have quantified glycol ethers or their metabolites in blood and/or urine amongst exposed populations. These biomonitoring levels indicate exposures to the glycol ethers, but do not by themselves indicate a health hazard risk. Biomonitoring Equivalents (BEs) have been created to provide the ability to interpret human biomonitoring data in a public health risk context. The BE is defined as the concentration of a chemical or metabolite in a biological fluid (blood or urine) that is consistent with exposures at a regulatory derived safe exposure limit, such as a tolerable daily intake (TDI). In this exercise, we derived BEs for general population exposures for selected E- and P-series glycol ethers based on their respective derived no effect levels (DNELs). Selected DNELs have been derived as part of respective Registration, Evaluation, Authorisation and Regulation of Chemicals (REACh) regulation dossiers in the EU. The BEs derived here are unique in the sense that they are the first BEs derived for urinary excretion of compounds following inhalation exposures. The urinary mass excretion fractions (Fue) of the acetic acid metabolites for the E-series GEs range from approximately 0.2 to 0.7. The Fues for the excretion of the parent P-series GEs range from approximately 0.1 to 0.2, with the exception of propylene glycol methyl ether and its acetate (Fue = 0.004). Despite the narrow range of Fues, the BEs exhibit a larger range, resulting from the larger range in DNELs across GEs. The BEs derived here can be used to interpret human biomonitoring data for inhalation exposures to GEs amongst the general population. Copyright © 2015 Elsevier GmbH. All rights reserved.

Benchmark Dose for Urinary Cadmium based on a Marker of Renal Dysfunction: A Meta-Analysis

PubMed Central

Woo, Hae Dong; Chiu, Weihsueh A.; Jo, Seongil; Kim, Jeongseon

2015-01-01

Background Low doses of cadmium can cause adverse health effects. Benchmark dose (BMD) and the one-sided 95% lower confidence limit of BMD (BMDL) to derive points of departure for urinary cadmium exposure have been estimated in several previous studies, but the methods to derive BMD and the estimated BMDs differ. Objectives We aimed to find the associated factors that affect BMD calculation in the general population, and to estimate the summary BMD for urinary cadmium using reported BMDs. Methods A meta-regression was performed and the pooled BMD/BMDL was estimated using studies reporting a BMD and BMDL, weighted by sample size, that were calculated from individual data based on markers of renal dysfunction. Results BMDs were highly heterogeneous across studies. Meta-regression analysis showed that a significant predictor of BMD was the cut-off point which denotes an abnormal level. Using the 95th percentile as a cut off, BMD5/BMDL5 estimates for 5% benchmark responses (BMR) of β2-microglobulinuria (β2-MG) estimated was 6.18/4.88 μg/g creatinine in conventional quantal analysis and 3.56/3.13 μg/g creatinine in the hybrid approach, and BMD5/BMDL5 estimates for 5% BMR of N-acetyl-β-d-glucosaminidase (NAG) was 10.31/7.61 μg/g creatinine in quantal analysis and 3.21/2.24 g/g creatinine in the hybrid approach. However, the meta-regression showed that BMD and BMDL were significantly associated with the cut-off point, but BMD calculation method did not significantly affect the results. The urinary cadmium BMDL5 of β2-MG was 1.9 μg/g creatinine in the lowest cut-off point group. Conclusion The BMD was significantly associated with the cut-off point defining the abnormal level of renal dysfunction markers. PMID:25970611

Zinc(II) complexes with potent cyclin-dependent kinase inhibitors derived from 6-benzylaminopurine: synthesis, characterization, X-ray structures and biological activity.

PubMed

Trávnícek, Zdenek; Krystof, Vladimír; Sipl, Michal

2006-02-01

The synthesis, characterization and biological activity of the first zinc(II) complexes with potent inhibitors of cyclin-dependent kinases (CDKs) derived from 6-benzylaminopurine are described. Based on the results following from elemental analyses, infrared, NMR and ES+MS (electrospray mass spectra in the positive ion mode) spectroscopies, conductivity data, thermal analysis and X-ray structures, the tetrahedral Zn(II) complexes of the compositions [Zn(Olo)Cl(2)](n) (1), [Zn(iprOlo)Cl(2)](n) (2), [Zn(BohH(+))Cl(3)] x H(2)O (3) and [Zn(iprOloH(+))Cl(3)] x H(2)O (4) have been prepared, where Olo=2-(2-hydroxyethylamino)-6-benzylamino-9-methylpurine (Olomoucine), iprOlo=2-(2-hydroxyethylamino)-6-benzylamino-9-isopropylpurine (i-propyl-Olomoucine), Boh=2-(3-hydroxypropylamino)-6-benzylamino-9-isopropylpurine (Bohemine). The 1D-polymeric chain structure for [Zn(Olo)Cl(2)](n) (1) as well as the monomeric one for [Zn(BohH(+))Cl(3)] x H(2)O (3) and [Zn(iprOloH(+))Cl(3)] x H(2)O (4) have been revealed unambiguously by single crystal X-ray analyses. The 1D-polymeric chain of 1 consists of Zn(Olo)Cl(2) monomeric units in which the Zn(II) ion is coordinated by two chlorine atoms and one oxygen atom of the 2-hydroxyethylamino group of Olomoucine. The next monomeric unit is bonded to Zn(II) through the N7 atom of a purine ring. Thus, each of Zn(II) ions is tetrahedrally coordinated and a ZnCl(2)NO chromophore occurs in the complex 1. The complexes 3 and 4 are mononuclear species with a distorted tetrahedral arrangement of donor atoms around the Zn(II) ion with a ZnCl(3)N chromophore. The corresponding CDK inhibitor, i.e., both Boh and iprOlo, is coordinated to Zn(II) via the N7 atom of the purine ring in 3 and 4. The cytotoxicity of the zinc(II) complexes against human melanoma, sarcoma, leukaemia and carcinoma cell lines has been determined as well as the inhibition of the CDK2/cyclin E kinase. A relationship between the structure and biological activity of the complexes is also discussed.

Optimization of the Alkyl Linker of TO Base Surrogate in Triplex-Forming PNA for Enhanced Binding to Double-Stranded RNA.

PubMed

Sato, Takaya; Sato, Yusuke; Nishizawa, Seiichi

2017-03-23

A series of triplex-forming peptide nucleic acid (TFP) probes carrying a thiazole orange (TO) base surrogate through an alkyl linker was synthesized, and the interactions between these so-called tFIT probes and purine-rich sequences within double-stranded RNA (dsRNA) were examined. We found that the TO base surrogate linker significantly affected both the binding affinity and the fluorescence response upon triplex formation with the target dsRNA. Among the probes examined, the TO base surrogate connected through the propyl linker in the tFIT probes increased the binding affinity by a factor of ten while maintaining its function as the fluorescent universal base. Isothermal titration calorimetry experiments revealed that the increased binding affinity resulted from the gain in the binding enthalpy, which could be explained by the enhanced π-stacking interaction between the TO base surrogate and the dsRNA part of the triplex. We expect that these results will provide a molecular basis for designing strong binding tFIT probes for fluorescence sensing of various kinds of purine-rich dsRNAs sequences including those carrying a pyrimidine-purine inversion. The obtained data also offers a new insight into further development of the universal bases incorporated in TFP. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xanthine Oxidase Inhibition with Febuxostat Attenuates Systolic Overload-induced Left Ventricular Hypertrophy and Dysfunction in Mice

PubMed Central

Xu, Xin; Hu, Xinli; Lu, Zhongbing; Zhang, Ping; Zhao, Lin; Wessale, Jerry L.; Bache, Robert J.; Chen, Yingjie

2008-01-01

The purine analog xanthine oxidase (XO) inhibitors (XOIs), allopurinol and oxypurinol, have been reported to protect against heart failure secondary to myocardial infarction or rapid ventricular pacing. Since these agents might influence other aspects of purine metabolism that could influence their effect, this study examined the effect of the non-purine XOI, febuxostat, on pressure overload-induced left ventricular (LV) hypertrophy and dysfunction. Transverse aortic constriction (TAC) in mice caused LV hypertrophy and dysfunction as well as increased myocardial nitrotyrosine at 8 days. TAC also caused increased phosphorylated Akt (p-AktSer473), p42/44 extracellular signal-regulated kinase (p-ErkThr202/Tyr204) and mammalian target of rapamycin (mTOR) (p-mTORSer2488). XO inhibition with febuxostat (5mg/kg/day by gavage for 8 days) beginning ~60 minutes after TAC attenuated the TAC-induced LV hypertrophy and dysfunction. Febuxostat blunted the TAC-induced increases in nitrotyrosine (indicating reduced myocardial oxidative stress), p-ErkThr202/Tyr204 and p-mTORSer2488, with no effect on total Erk or total mTOR. Febuxostat had no effect on myocardial p-AktSer473 or total Akt. The results suggest that XO inhibition with febuxostat reduced oxidative stress in the pressure overloaded LV, thereby diminishing the activation of pathways that result in pathologic hypertrophy and contractile dysfunction. PMID:18995179

Involvement of purines and phosphoinositides in spontaneous and progesterone-induced nuclear maturation of Bufo arenarum oocytes.

PubMed

Zelarayán, L; Oterino, J; Sánchez Toranzo, G; Bühler, M I

2000-07-01

Although progesterone is the established maturation inducer in amphibia, it has been demonstrated that Bufo arenarum oocytes resume meiosis with no need of an exogenous hormonal stimulus if deprived of their enveloping follicle cells, a phenomenon called "spontaneous maturation." The present studies were designed to evaluate the participation of purines and phosphoinositides in the spontaneous and progesterone-induced maturation in Bufo arenarum full-grown oocytes. The presented data demonstrate that high intracellular levels of purines such as cAMP or guanosine can inhibit both spontaneous and progesterone-induced maturation in full-grown denuded Bufo arenarum oocytes. Moreover, the fact that the mycophenolic acid was able to induce maturation in denuded oocytes obtained during the nonreproductive period in a manner similar to that of the progesterone and also to increase the percentages of spontaneous maturation suggests that in Bufo arenarum, inosine monophosphate dehydrogenase inhibition is an important step in the resumption of meiosis. Inhibition of the phosphatidylinositol 4,5 bisphosphate hydrolysis by treatment of denuded oocytes with neomycin totally blocks spontaneous and progesterone-induced maturation, suggesting that the products of this hydrolysis (1,2 diacylglycerol and inositol 1,4,5 trisphosphate) may be involved in the maturation process of Bufo. In addition, our results indicate that the activation of protein kinase C is also involved in both types of maturation.

A molecular view of cisplatin's mode of action: interplay with DNA bases and acquired resistance.

PubMed

Marques, M Paula M; Gianolio, Diego; Cibin, Giannantonio; Tomkinson, John; Parker, Stewart F; Valero, Rosendo; Pedro Lopes, R; Batista de Carvalho, Luis A E

2015-02-21

The interaction of the widely used anticancer drug cisplatin with DNA bases was studied by EXAFS and vibrational spectroscopy (FTIR, Raman and INS), coupled with DFT/plane-wave calculations. Detailed information was obtained on the local atomic structure around the Pt(ii) centre, both in the cisplatin-purine (adenine and guanine) and cisplatin-glutathione adducts. Simultaneous neutron and Raman scattering experiments allowed us to obtain a reliable and definite picture of this cisplatin interplay with its main pharmacological target (DNA), at the molecular level. The vibrational experimental spectra were fully assigned in the light of the calculated pattern for the most favoured geometry of each drug-purine adduct, and cisplatin's preference for guanine (G) relative to adenine (A) within the DNA double helix was experimentally verified: a complete N by S substitution in the metal coordination sphere was only observed for [cDDP-A2], reflecting a somewhat weaker Pt-A binding relative to Pt-G. The role of glutathione on the drug's pharmacokinetics, as well as on the stability of platinated DNA adducts, was evaluated as this is the basis for glutathione-mediated intracellular drug scavenging and in vivo resistance to Pt-based anticancer drugs. Spectroscopic evidence of the metal's preference for glutathione's sulfur over purine's nitrogen binding sites was gathered, at least two sulfur atoms being detected in platinum's first coordination sphere.

Functional expression and characterization of a purine nucleobase transporter gene from Leishmania major.

PubMed

Sanchez, Marco A; Tryon, Rob; Pierce, Steven; Vasudevan, Gayatri; Landfear, Scott M

2004-01-01

Leishmania major, like all the other kinetoplastid protozoa, are unable to synthesize purines and rely on purine nucleobase and nucleoside acquisition across the parasite plasma membrane by specific permeases. Although, several genes have been cloned that encode nucleoside transporters in Leishmania and Trypanosoma brucei, much less progress has been made on nucleobase transporters, especially at the molecular level. The studies reported here have cloned and expressed the first gene for a L. major nucleobase transporter, designated LmaNT3. The LmaNT3 permease shows 33% identity to L. donovani nucleoside transporter 1.1 (LdNT1.1) and is, thus, a member of the equilibrative nucleoside transporter (ENT) family. ENT family members identified to date are nucleoside transporters, some of which also transport one or several nucleobases. Functional expression studies in Xenopus laevis oocytes revealed that LmaNT3 mediates high levels of uptake of hypoxanthine, xanthine, adenine and guanine. Moreover, LmaNT3 is an high affinity transporter with K(m) values for hypoxanthine, xanthine, adenine and guanine of 16.5 +/- 1.5, 8.5 +/- 0.6, 8.5 +/- 1.1, and 8.8 +/- 4.0 microM, respectively. LmaNT3 is, thus, the first member of the ENT family identified in any organism that functions as a nucleobase rather than nucleoside or nucleoside/nucleobase transporter.

Roles of the amino group of purine bases in the thermodynamic stability of DNA base pairing.

PubMed

Nakano, Shu-ichi; Sugimoto, Naoki

2014-08-05

The energetic aspects of hydrogen-bonded base-pair interactions are important for the design of functional nucleotide analogs and for practical applications of oligonucleotides. The present study investigated the contribution of the 2-amino group of DNA purine bases to the thermodynamic stability of oligonucleotide duplexes under different salt and solvent conditions, using 2'-deoxyriboinosine (I) and 2'-deoxyribo-2,6-diaminopurine (D) as non-canonical nucleotides. The stability of DNA duplexes was changed by substitution of a single base pair in the following order: G • C > D • T ≈ I • C > A • T > G • T > I • T. The apparent stabilization energy due to the presence of the 2-amino group of G and D varied depending on the salt concentration, and decreased in the water-ethanol mixed solvent. The effects of salt concentration on the thermodynamics of DNA duplexes were found to be partially sequence-dependent, and the 2-amino group of the purine bases might have an influence on the binding of ions to DNA through the formation of a stable base-paired structure. Our results also showed that physiological salt conditions were energetically favorable for complementary base recognition, and conversely, low salt concentration media and ethanol-containing solvents were effective for low stringency oligonucleotide hybridization, in the context of conditions employed in this study.

Urinary isoflavone concentrations are inversely associated with lower cardiometabolic risk markers in pregnant U.S. women

USDA-ARS?s Scientific Manuscript database

Some evidence suggests that phytoestrogens such as soy-derived isoflavones may have beneficial effects on cardiovascular health and glycemic control. These data are mainly limited to postmenopausal women or individuals at elevated cardiometabolic risk. There is a lack of data for pregnant women who ...

Influence of Mesenchymal Stem Cells Conditioned Media on Proliferation of Urinary Tract Cancer Cell Lines and Their Sensitivity to Ciprofloxacin.

PubMed

Maj, Malgorzata; Bajek, Anna; Nalejska, Ewelina; Porowinska, Dorota; Kloskowski, Tomasz; Gackowska, Lidia; Drewa, Tomasz

2017-06-01

Mesenchymal stem cells (MSCs) are known to interact with cancer cells through direct cell-to-cell contact and secretion of paracrine factors, although their exact influence on tumor progression in vivo remains unclear. To better understand how fetal and adult stem cells affect tumors, we analyzed viability of human renal (786-0) and bladder (T24) carcinoma cell lines cultured in conditioned media harvested from amniotic fluid-derived stem cells (AFSCs) and adipose-derived stem cells (ASCs). Both media reduced metabolic activity of 786-0 cells, however, decreased viability of T24 cells was noted only after incubation with conditioned medium from ASCs. To test the hypothesis that MSCs-secreted factors might be involved in chemoresistance acquisition, we further analyzed influence of mesenchymal stem cell conditioned media (MSC-CM) on cancer cells sensitivity to ciprofloxacin, that is considered as potential candidate agent for urinary tract cancers treatment. Significantly increased resistance to tested drug indicates that MSCs may protect cancer cells from chemotherapy. J. Cell. Biochem. 118: 1361-1368, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Inhibition of bacterial adherence by cranberry juice: potential use for the treatment of urinary tract infections.

PubMed

Sobota, A E

1984-05-01

Cranberry juice has been widely used for the treatment and prevention of urinary tract infections and is reputed to give symptomatic relief from these infections. Attempts to account for the potential benefit derived from the juice have focused on urine acidification and bacteriostasis. In this investigation it is demonstrated that cranberry juice is a potent inhibitor of bacterial adherence. A total of 77 clinical isolates of Escherichia coli were tested. Cranberry juice inhibited adherence by 75 per cent or more in over 60 per cent of the clinical isolates. Cranberry cocktail was also given to mice in the place of their normal water supply for a period of 14 days. Urine collected from these mice inhibited adherence of E. coli to uroepithelial cells by approximately 80 per cent. Antiadherence activity could also be detected in human urine. Fifteen of 22 subjects showed significant antiadherence activity in the urine 1 to 3 hours after drinking 15 ounces of cranberry cocktail. It is concluded that the reported benefits derived from the use of cranberry juice may be related to its ability to inhibit bacterial adherence.

Effect of benzyl amino purine and indole-3-acetic acid on propagation of Sterculia foetida in vitro

NASA Astrophysics Data System (ADS)

Yuniastuti, E.; Widodo, C. E.; Samanhudi; Delfianti, M. N. I.

2018-03-01

Sterculia foetida is an oval seed plants that can be used as biofuel, which is one of the environmental friendly fuels. This plant is quite hard to find because not many peoples cultivate the plants. An in vitro propagation is one way to preserve the plant. This research aimed to determine optimum concentration of benzyl amino purine (BAP) and indole-3-acetic acid (IAA) to propagate S. foetida in vitro. The results showed that woody plant medium (WPM) added by 4 mg L BAP-1 and 0.5 mg L IAA-1 was able to produce complete plantlet, whereas those added by 4 mg L BAP-1 and 1 mg L IAA-1 generated the best growth of shoot and leaves.

First Evidence on the Role of Heavy Ion Irradiation of Meteorites and Formamide in the Origin of Biomolecules

NASA Astrophysics Data System (ADS)

Saladino, Raffaele; Carota, Eleonora; Botta, Giorgia; Kapralov, Michail; Timoshenko, Gennady N.; Rozanov, Alexei; Krasavin, Eugene; Di Mauro, Ernesto

2016-11-01

Formamide (NH2CHO) has been irradiated in condensed phase at 273 K by 11B-boron beams in the presence of powdered meteorites of the chondrite and stony-iron types. Relative to the controls (no radiation or no catalysis), a variegate panel of compounds was observed, including purine and pyrimidine nucleobases (uracil, cytosine, adenine, and guanine), nucleobase analogues, heterocycles, and carboxylic acids involved in metabolic pathways. The presence of amino imidazole carbonitrile (AICN), 4,6-diamino purine (4,6-DAP) and 2,4-diamino pyrimidine (2,4-DAPy) among the observed products suggests the occurrence of an unified mechanism based on the generation of radical cyanide species (•CN). These observations contribute to outline plausible prebiotic scenarios involving 11B-boron as energy source.

Ribonucleotides.

PubMed

Sutherland, John D

2010-04-01

It has normally been assumed that ribonucleotides arose on the early Earth through a process in which ribose, the nucleobases, and phosphate became conjoined. However, under plausible prebiotic conditions, condensation of nucleobases with ribose to give beta-ribonucleosides is fraught with difficulties. The reaction with purine nucleobases is low-yielding and the reaction with the canonical pyrimidine nucleobases does not work at all. The reasons for these difficulties are considered and an alternative high-yielding synthesis of pyrimidine nucleotides is discussed. Fitting the new synthesis to a plausible geochemical scenario is a remaining challenge but the prospects appear good. Discovery of an improved method of purine synthesis, and an efficient means of stringing activated nucleotides together, will provide underpinning support to those theories that posit a central role for RNA in the origins of life.

Adenosine Deaminase (ADA)-Deficient Severe Combined Immune Deficiency (SCID): Molecular Pathogenesis and Clinical Manifestations.

PubMed

Bradford, Kathryn L; Moretti, Federico A; Carbonaro-Sarracino, Denise A; Gaspar, Hubert B; Kohn, Donald B

2017-10-01

Deficiency of adenosine deaminase (ADA, EC3.5.4.4), a housekeeping enzyme of purine metabolism encoded by the Ada gene, is a cause of human severe combined immune deficiency (SCID). Numerous deleterious mutations occurring in the ADA gene have been found in patients with profound lymphopenia (T - B - NK - ), thus underscoring the importance of functional purine metabolism for the development of the immune defense. While untreated ADA SCID is a fatal disorder, there are multiple life-saving therapeutic modalities to restore ADA activity and reconstitute protective immunity, including enzyme replacement therapy (ERT), allogeneic hematopoietic stem cell transplantation (HSCT) and gene therapy (GT) with autologous gene-corrected hematopoietic stem cells (HSC). We review the pathogenic mechanisms and clinical manifestations of ADA SCID.

Effect of Purine Co-Transmitters on Automatic Activity Caused by Norepinephrine in Myocardial Sleeves of Pulmonary Veins.

PubMed

Karimova, V M; Pustovit, K B; Abramochkin, D V; Kuz'min, V S

2017-03-01

We studied the effect of extracellular purine nucleotides (NAD + and ATP) on spontaneous arrhythmogenic activity caused by norepinephrine in myocardial sleeves of pulmonary veins. In pulmonary veins, NAD + and ATP reduced the frequency of action potentials and their duration at regular type of spontaneous activity caused by norepinephrine. NAD + and ATP lengthened the intervals between spike bursts at periodic (burst) type of spontaneous activity. In addition, ATP shortened the duration of spike bursts and the number of action potentials in the "bursts" caused by norepinephrine in the pulmonary veins. It was hypothesized that NAD + and ATP attenuate the effects of sympathetic stimulation and when released together with norepinephrine from sympathetic endings in vivo, probably, reduce arrhythmogenic activity in myocardial sleeves of pulmonary veins.

A Canonical Correlation Analysis of AIDS Restriction Genes and Metabolic Pathways Identifies Purine Metabolism as a Key Cooperator.

PubMed

Ye, Hanhui; Yuan, Jinjin; Wang, Zhengwu; Huang, Aiqiong; Liu, Xiaolong; Han, Xiao; Chen, Yahong

2016-01-01

Human immunodeficiency virus causes a severe disease in humans, referred to as immune deficiency syndrome. Studies on the interaction between host genetic factors and the virus have revealed dozens of genes that impact diverse processes in the AIDS disease. To resolve more genetic factors related to AIDS, a canonical correlation analysis was used to determine the correlation between AIDS restriction and metabolic pathway gene expression. The results show that HIV-1 postentry cellular viral cofactors from AIDS restriction genes are coexpressed in human transcriptome microarray datasets. Further, the purine metabolism pathway comprises novel host factors that are coexpressed with AIDS restriction genes. Using a canonical correlation analysis for expression is a reliable approach to exploring the mechanism underlying AIDS.

Impact of pesticide exposure misclassification on estimates of relative risks in the Agricultural Health Study.

PubMed

Blair, Aaron; Thomas, Kent; Coble, Joseph; Sandler, Dale P; Hines, Cynthia J; Lynch, Charles F; Knott, Charles; Purdue, Mark P; Zahm, Shelia Hoar; Alavanja, Michael C R; Dosemeci, Mustafa; Kamel, Freya; Hoppin, Jane A; Freeman, Laura Beane; Lubin, Jay H

2011-07-01

The Agricultural Health Study (AHS) is a prospective study of licensed pesticide applicators and their spouses in Iowa and North Carolina. We evaluate the impact of occupational pesticide exposure misclassification on relative risks using data from the cohort and the AHS Pesticide Exposure Study (AHS/PES). We assessed the impact of exposure misclassification on relative risks using the range of correlation coefficients observed between measured post-application urinary levels of 2,4-dichlorophenoxyacetic acid (2,4-D) and a chlorpyrifos metabolite and exposure estimates based on an algorithm from 83 AHS pesticide applications. Correlations between urinary levels of 2,4-D and a chlorpyrifos metabolite and algorithm estimated intensity scores were about 0.4 for 2,4-D (n=64), 0.8 for liquid chlorpyrifos (n=4) and 0.6 for granular chlorpyrifos (n=12). Correlations of urinary levels with kilograms of active ingredient used, duration of application, or number of acres treated were lower and ranged from -0.36 to 0.19. These findings indicate that a priori expert-derived algorithm scores were more closely related to measured urinary levels than individual exposure determinants evaluated here. Estimates of potential bias in relative risks based on the correlations from the AHS/PES indicate that non-differential misclassification of exposure using the algorithm would bias estimates towards the null, but less than that from individual exposure determinants. Although correlations between algorithm scores and urinary levels were quite good (ie, correlations between 0.4 and 0.8), exposure misclassification would still bias relative risk estimates in the AHS towards the null and diminish study power.

Mutations in SOX17 are associated with congenital anomalies of the kidney and the urinary tract.

PubMed

Gimelli, Stefania; Caridi, Gianluca; Beri, Silvana; McCracken, Kyle; Bocciardi, Renata; Zordan, Paola; Dagnino, Monica; Fiorio, Patrizia; Murer, Luisa; Benetti, Elisa; Zuffardi, Orsetta; Giorda, Roberto; Wells, James M; Gimelli, Giorgio; Ghiggeri, Gian Marco

2010-12-01

Congenital anomalies of the kidney and the urinary tract (CAKUT) represent a major source of morbidity and mortality in children. Several factors (PAX, SOX,WNT, RET, GDFN, and others) play critical roles during the differentiation process that leads to the formation of nephron epithelia. We have identified mutations in SOX17, an HMG-box transcription factor and Wnt signaling antagonist, in eight patients with CAKUT (seven vesico-ureteric reflux, one pelvic obstruction). One mutation, c.775T>A (p.Y259N), recurred in six patients. Four cases derived from two small families; renal scars with urinary infection represented the main symptom at presentation in all but two patients. Transfection studies indicated a 5-10-fold increase in the levels of the mutant protein relative to wild-type SOX17 in transfected kidney cells. Moreover we observed a corresponding increase in the ability of SOX17 p.Y259N to inhibit Wnt/β-catenin transcriptional activity, which is known to regulate multiple stages of kidney and urinary tract development. In conclusion, SOX17 p.Y259N mutation is recurrent in patients with CAKUT. Our data shows that this mutation correlates with an inappropriate accumulation of SOX17-p.Y259N protein and inhibition of the β-catenin/Wnt signaling pathway. These data indicate a role of SOX17 in human kidney and urinary tract development and implicate the SOX17-p.Y259N mutation as a causative factor in CAKUT. © 2010 Wiley-Liss, Inc.

Mutations in SOX17 are Associated with Congenital Anomalies of the Kidney and the Urinary Tract

PubMed Central

Gimelli, Stefania; Caridi, Gianluca; Beri, Silvana; McCracken, Kyle; Bocciardi, Renata; Zordan, Paola; Dagnino, Monica; Fiorio, Patrizia; Murer, Luisa; Benetti, Elisa; Zuffardi, Orsetta; Giorda, Roberto; Wells, James M; Gimelli, Giorgio; Ghiggeri, Gian Marco

2010-01-01

Congenital anomalies of the kidney and the urinary tract (CAKUT) represent a major source of morbidity and mortality in children. Several factors (PAX, SOX,WNT, RET, GDFN, and others) play critical roles during the differentiation process that leads to the formation of nephron epithelia. We have identified mutations in SOX17, an HMG-box transcription factor and Wnt signaling antagonist, in eight patients with CAKUT (seven vesico-ureteric reflux, one pelvic obstruction). One mutation, c.775T>A (p.Y259N), recurred in six patients. Four cases derived from two small families; renal scars with urinary infection represented the main symptom at presentation in all but two patients. Transfection studies indicated a 5–10-fold increase in the levels of the mutant protein relative to wild-type SOX17 in transfected kidney cells. Moreover we observed a corresponding increase in the ability of SOX17 p.Y259N to inhibit Wnt/β-catenin transcriptional activity, which is known to regulate multiple stages of kidney and urinary tract development. In conclusion, SOX17 p.Y259N mutation is recurrent in patients with CAKUT. Our data shows that this mutation correlates with an inappropriate accumulation of SOX17-p.Y259N protein and inhibition of the β-catenin/Wnt signaling pathway. These data indicate a role of SOX17 in human kidney and urinary tract development and implicate the SOX17–p.Y259N mutation as a causative factor in CAKUT. Hum Mutat 31:1352–1359, 2010. © 2010 Wiley-Liss, Inc. PMID:20960469

[Atypical urothelial cells (AUC): A Bethesda-derived wording applicable to urinary cytopathology].

PubMed

Piaton, Eric; Advenier, Anne-Sophie; Benaïm, Gilles; Petrucci, Myriam Decaussin; Lechevallier, Florence Mege; Ruffion, Alain

2011-02-01

To investigate (1) whether sparse nuclear atypias involving deep urothelial cells have a diagnostic or prognostic value in urinary cytology, and (2) whether the terms atypical urothelial cells "of undetermined significance" (AUC-US) or "cannot exclude high grade" (AUC-H) might be used to standardize urinary cytology reports. Atypical urothelial cells (AUC) were defined as deep cells with nuclear abnormalities (increased N/C ratio, eccentric nucleus, hyperchromatism and/or irregular shape) in small number not allowing their categorization as malignant, high grade. We studied 435 urinary samples from 126 patients with AUC at any step of their clinical history, followed up over a 10-year period (1999-2009). Every case was compared with histopathology within 6 months and to long term follow-up including cystoscopy and histopathology combined. A total of 183 AUC was recorded. AUC were associated with negative, benign or low grade histological results in 36 of 106 cases (33.9 %) within 6 months, but a high grade was simultaneously documented in 70 cases (66 %). AUC preceded high-grade lesions in 66 cases (36.1 % of all AUC) in a mean interval of 10.5±12.0 months. Overall, AUC were associated with or predictive of high-grade lesions in 135 cases (73.8 %). AUC have a diagnostic and prognostic value. Applying the terms AUC-US and AUC-H to urinary cytopathology reports would allow, as for the Bethesda system for cervical or vaginal cytologic diagnoses, better appreciation of the risk of progression to high grade tumours in cases with atypias. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Antiadhesive Activity and Metabolomics Analysis of Rat Urine after Cranberry (Vaccinium macrocarpon Aiton) Administration.

PubMed

Peron, Gregorio; Pellizzaro, Anna; Brun, Paola; Schievano, Elisabetta; Mammi, Stefano; Sut, Stefania; Castagliuolo, Ignazio; Dall'Acqua, Stefano

2017-07-19

Cranberry (Vaccinium macrocarpon Aiton) is used to treat noncomplicated urinary tract infections (UTIs). A-type procyanidins (PAC-A) are considered the active constituents able to inhibit bacterial adhesion to the urinary epithelium. However, the role of PAC-A in UTIs is debated, because of their poor bioavailability, extensive metabolism, limited knowledge about urinary excretion, and contradictory clinical trials. The effects of 35-day cranberry supplementation (11 mg/kg PAC-A, 4 mg/kg PAC-B) were studied in healthy rats using a ultra performance liquid chromatography-mass spectrometry (UPLC-MS)-based metabolomics approach. Microbial PAC metabolites, such as valeric acid and valerolactone derivatives, were related to cranberry consumption. An increased urinary excretion of glucuronidated metabolites was also observed. In a further experiment, urine samples were collected at 2, 4, 8, and 24 h after cranberry intake and their antiadhesive properties were tested against uropathogenic Escherichia coli. The 8 h samples showed the highest activity. Changes in urinary composition were studied by ultra performance liquid chromatography-time-of-flight (UPLC-QTOF), observing the presence of PAC metabolites. The PAC-A2 levels were measured in all collected samples, and the highest amounts, on the order of ng/mL, were found in the samples collected after 4 h. Results indicate that the antiadhesive activity against uropathogenic bacteria observed after cranberry consumption is ascribable to PAC-A metabolites rather than to a direct PAC-A effect, as the measured PAC-A levels in urine was lower than those reported as active in the literature.