High Purine Content Research Articles

Unraveling genetic underpinnings of purine content in pork

The significance of purine base content as an important nutrition indicator in foods arises from its potential to trigger hyperuricemia or gout via high-purine diet. Livestock meats, including pork, generally contain moderate to high total purine content (TP). Recent research revealed substantial variations within and across pig breeds, implying genetic factors influencing this trait. Thus, this study aimed to unravel the genetic underpinnings governing purine base content in pork. The heritability estimates (h2) for the four purine traits ranged from 0.14 to 0.35. A total of 14, 36, 19 and 25 quantitative trait loci (QTLs) were identified for guanine, adenine, hypoxanthine, and TP, respectively. Our comprehensive gene set enrichment analysis and gene network analysis revealed 15 promising candidate genes intricately interwoven within diverse purine metabolism pathways, such as purine ribonucleotide metabolic process, purine nucleotide metabolism and transport, and purine salvage pathways, all contributing to TP. Strikingly, most genetic variants significantly associated with TP displayed analogous effects on multiple purine bases. Two distinct and highly significant QTLs (P < 10-12) emerged on Sus Scrofa chromosome (SSC) 12: one impacting guanine content and the other concurrently influencing adenine and hypoxanthine levels. The peak of the guanine QTL on SSC12 resided 1.1 kb downstream of the transmembrane protein 238 like (TMEM238L) gene and is encapsulated within a genomic segment characterized by the histone modification H3K27me3. Focused fine-mapping for the SSC12 QTL associated with adenine and hypoxanthine levels narrowed its scope to around 172 kb, encompassing the growth arrest specific 7 (GAS7) and myosin heavy chain 13 (MYH13) genes. However, the observed QTL effect was not attributed to any missense mutations within the two genes. This pioneering study unveils the genetic variations and candidate genes associated with purine content in livestock, laying a robust foundation for the selective breeding of pig lines with reduced purine base content.

Exploring the anti-gout potential of sunflower receptacles alkaloids: A computational and pharmacological analysis

Gout, a painful condition marked by elevated uric acid levels often linked to the diet's high purine and alcohol content, finds a potential treatment target in xanthine oxidase (XO), a crucial enzyme for uric acid production. This study explores the therapeutic properties of alkaloids extracted from sunflower (Helianthus annuus L.) receptacles against gout. By leveraging computational chemistry and introducing a novel R-based clustering algorithm, “TriDimensional Hierarchical Fingerprint Clustering with Tanimoto Representative Selection (3DHFC-TRS)," we assessed 231 alkaloid molecules from sunflower receptacles. Our clustering analysis pinpointed six alkaloids with significant gout-targeting potential, particularly emphasizing the fifth cluster's XO inhibition capabilities. Through molecular docking and the BatchDTA prediction model, we identified three top compounds—2-naphthylalanine, medroxalol, and fenspiride—with the highest XO affinity. Further molecular dynamics simulations assessed their enzyme active site interactions and binding free energies, employing MM-PBSA calculations. This investigation not only highlights the discovery of promising compounds within sunflower receptacle alkaloids via LC-MS but also introduces medroxalol as a novel gout treatment candidate, showcasing the synergy of computational techniques and LC-MS in drug discovery.

Removal of substrate inhibition of Acinetobacter baumannii xanthine oxidase by point mutation at Gln-201 enables efficient reduction of purine content in fish sauce

Xanthine oxidase is an oxidase that has a molybdopterin structure with substrate inhibition. Here, we show that a single point mutation (Q201) in the Acinetobacter baumannii xanthine oxidase (AbXOD) obtained mutant Q201E (kcat =799.44 s−1, no inhibition) with high enzyme activity and decrease of substrate inhibition in 5 mmol/L high substrate model, and which cause two loops structure change at active center, characterized by complete loss of substrate inhibition without reduction of enzymatic activity. Molecular docking results showed that the change of flexible loop increased the affinity between substrate and enzyme, and the formation of a π-π bond and two hydrogen bonds made the substrate more stable in the active center. Ultimately, Q201E can still maintain better enzyme activity under high purine content (an approximately 7-fold improvement over the wild-type), indicating a broader application prospect in the manufacture of low-purine food.

In Silico Analyses of the Role of Codon Usage at the Hemagglutinin Cleavage Site in Highly Pathogenic Avian Influenza Genesis.

A vast diversity of 16 influenza hemagglutinin (HA) subtypes are found in birds. Interestingly, viruses from only two subtypes, H5 and H7, have so far evolved into highly pathogenic avian influenza viruses (HPAIVs) following insertions or substitutions at the HA cleavage site by the viral polymerase. The mechanisms underlying this striking subtype specificity are still unknown. Here, we compiled a comprehensive dataset of 20,488 avian influenza virus HA sequences to investigate differences in nucleotide and amino acid usage at the HA cleavage site between subtypes and how these might impact the genesis of HPAIVs by polymerase stuttering and realignment. We found that sequences of the H5 and H7 subtypes stand out by their high purine content at the HA cleavage site. In addition, fewer substitutions were necessary in H5 and H7 HAs than in HAs from other subtypes to acquire an insertion-prone HA cleavage site sequence, as defined based on in vitro and in vivo data from the literature. Codon usage was more favorable for HPAIV genesis in sequences of viruses isolated from species or geographical regions in which HPAIV genesis is more frequently observed in nature. The results of the present analyses suggest that the subtype restriction of HPAIV genesis to H5 and H7 influenza viruses might be due to the particular codon usage at the HA cleavage site in these subtypes.

Distribution Pattern of Serum Uric Acid Level Before and After National Festival Dashain among Patients Visiting Tertiary Hospital, Kathmandu, Nepal

Introduction: Dashain, one of the national festivals in Nepal, celebrated with excessive consumption of high purine content foods, alcoholic and soft beverages. These foods have been associated with higher Serum Uric Acid (SUA) levels leading to hyperuricemia. This study was intended to evaluate the distribution pattern of SUA level a month before and after this festival for two consecutive years.&#x0D; &#x0D; Methods and Materials: The data of 5818 patients visiting Clinical Biochemistry Laboratory, Tribhuvan University Teaching Hospital for SUA test (a month before and after Dashain festival for two consecutive years; 2017 - 2018 A.D.) were collected and analyzed. The statistical analysis was done using SPSS version 21. Continuous variables were expressed as mean ± SD taking 95% confidence interval and p values of &lt;0.05 was considered to be statistically significant. Mann-Whitney U test was used to compare the variables.&#x0D; &#x0D; Results: The mean SUA levels before and after Dashain in two consecutive years were 333.5 ± 112.1 μmol/L and 334.2±114.7 μmol/L in 2017 A.D. and 322.6 ± 103.9μmol/L and 343.2± 111.4 μmol/L in 2018 A.D. There was a significantly elevated level of the mean SUA level after Dashain festival in 2018 among both sexes (p-value &lt;0.05). The age-wise distribution of mean SUA after the Dashain festival was consistent with increasing age among the study population.&#x0D; &#x0D; Conclusion: The study concluded that the Dashain festival has an impact on increasing the SUA level.&#x0D;

Reduksi Purin pada Emping Melinjo Melalui Pre-treatment Perendaman Emping Mentah

Melinjo chips (emping as local name) has high purine content which can be related to the high uric acid level in blood that lead to joint inflamation due to the sendimentation of uric acid. The objective of this research is to prove that soaking process can reduce purine content in emping and to know the effect of the soaking process length in purine reduction. Soaking time (2, 5, and 12 hours) and emping brand (Sriti, A1 and Koki) were used as the treatments. Purine compounds such as adenine and hypoxanthine were analyzed by using High Performance Liquid Chromatography (HPLC) method with C18 column and UV detector. The three emping samples were also analyzed by using sensory evaluation to know the consumer preference toward the treated fried emping. Results obtained from this research were that soaking process can reduce both adenine and hypoxanthin content in emping. Soaking for 2 hours in water could reduce adenine content 13 – 39% and hypoxanthine content 4 – 60%. Soaking process for 2 hours on emping could reduce up to 50% of total purine base content in A1 brand, however, soaking time was not directly proportional to the decrease in purine levels. Purine content after 5 and 12 hours soaking tend to be fluctuative. Emping samples that were soaked in the water have a decrease in preference by the panelists either in color, aroma, taste, texture or in overall, but still accepted by panelists.

Thermostability Trends of TNA:DNA Duplexes Reveal Strong Purine Dependence.

The development of high fidelity polymerases and streamlined synthesis of threose nucleic acid (TNA) triphosphates and phosphoramidites has made TNA accessible as a motif for generating nuclease-resistant high-affinity aptamers, antisense oligos, and synthetic genetic biopolymers. Little is known, however, about the thermostability trends of TNA:DNA duplexes. Here we investigate the thermostability of 14 TNA:DNA duplexes with the goal of elucidating the fundamental factors governing TNA:DNA duplex stability. We find that purine content in TNA significantly influences the stability and conformation of TNA:DNA duplexes. Low TNA purine content destabilizes duplexes, with Tm values often 5 °C lower than analogous DNA:DNA and RNA:DNA duplexes. By contrast, TNA:DNA duplexes having high TNA purine content display greater stability than DNA:DNA or RNA:DNA duplexes having the same sequences. High TNA purine content leads TNA:DNA duplexes to adopt conformations similar to RNA:RNA (A-form) configuration, whereas duplexes with low TNA purine content have conformations more similar to DNA:DNA (B-form) configuration. These insights provide a basis for understanding and predicting TNA:DNA duplex stability, which is anticipated to guide the practical use of TNA in biotechnology applications.

Influence of d-Amino Acids in Beer on Formation of Uric Acid.

SUMMARYExcessive intake of beer could increase serum uric acid levels, leading to high risk of gout, which was previously attributed to high purine content in beer. Recent reports that purine-rich vegetables and bean products do not cause higher uric acid levels do not support this theory. Why excessive intake of beer could increase a high risk of gout has been unclear. Other factors affecting the accumulation of uric acid in the blood have been explored. Beer contains relatively high levels of d-amino acids due to the racemization of l-amino acids induced by food processing. d-amino acid was catalyzed by d-amino acid oxidase to produce H2O2, which is further oxidized in the presence of Fe2+ to produce hydroxyl radicals, resulting in DNA damage and formation of a large amount of purine bases, which are oxidized to uric acid by a series of enzymes. Some food ingredients, such as vitamins and I–, prompt d-amino acids to form uric acid. d-amino acids in beer are one of the key factors responsible for the increase in uric acid levels. The biological response of d-amino acids could explain gout occurrence in beer drinkers.

EATING PATTERN CONTAINS EXCESSIVE PURIN SUBSTANCE IMPROVING GOUT ARTHRITIS PREVALENCE IN COMMUNITIES IN KOTABUNAN VILLAGE

Background: Gout Arthritis is an inflammatory disease in the joints that causes extreme pain, swelling, sometimes redness and is difficult to move and if it lasts for a long time it can cause deformity in the affected joint. Objective: To determine the relationship between diet and gout arthritis. The design used is correlation. Method: This type of research is analytic descriptive research with cross-sectional approach. the location of the study was in Kotabunan Village, Kotabunan Subdistrict, Bolaang Mongondow Timur Regency from July 21 to July 23, 2018. The sampling technique used a total sample with 49 respondents. The instrument uses a food recall questionnaire 2 x 24 hours. Results: Statistical test with chi-square with significance level (α) 0.05. Correlation test results obtained ρ = 0.002. The conclusion : This study is that there is a relationship between diet and the incidence of gout arthritis, where the more often the consumption of high purine content, the higher the value of uric acid levels. Suggestion: People can maintain their diet well considering there are still many people who do not maintain their diet so that it results in increased levels of uric acid in the blood.

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

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.

The influence of purine content in diet on serum uric acid of old males

Eleven old male patients with hyperuricemia were collected ( hyperuricemia group,65-90 years old ).10 healthy middle-aged males ( middle-aged group,30-40 years old) and 10 healthy old males ( older group 60-70 years old ) with normal blood uric acid level were used as controls.All of the subjects were given low purine content diet ( 250 mg/d ) for 3 days followed by high purine content diet ( 800 mg/d ) consecutively for another three days.The samples of fasting blood and 24 h urine were collected for assay.The results showed that there were no significant changes of serum uric acid ( UA ) concentration in three groups after low purine content diet.But the levels of serum UA in three groups all increased significantly after high purine content diet,and the change was higher in hyperuricemia group than middle-aged group [ ( 507.7 ± 108.1 vs 378.9 ± 80.1 ) μmol/L,P＜0.05 ].24 h urine uric acid excretion in three groups was all significantly decreased after low purine content diet and increased after high purine content diet.After high purine content diet,24 h urine uric acid was lower in hyperuricemia group than middle-aged group [ ( 2.99 ± 1.21 vs 3.62 ± 1.02 ) mmol/24 h,P＜0.05 ].Blood urea nitrogen levels in all subjects decreased after low purine content diet and increased after high purine content diet ( P＜0.05 or P＜0.01 ).Creatinine clearance rate in hyperuricemia group was decreased after high purine content diet compared with baseline [ (75.3 ± 20.3 vs 80.7 ±20.0) ml/min ],and there were no significant changes in other groups after low and high purine content diet.24 h urine protein in hyperuricemia group was higher than middle-aged group ( P＜0.05 ),and increased after high purine content diet with significant difference ( P＜0.05 ).These results suggest that high purine content diet and decreased by renal uric acid clearance mainly contribute to hyperuricemia in old people. Key words: Hyperuricemia; Purine load diet; Old male; Uric acid clearance

Effects of feeding fat‐coated butyrate on mucosal morphology and function in the small intestine of the pig

As shown earlier, pig rations with high starch and purine content initiate mucosal hypertrophy by stimulating mitotic activity and DNA formation in the small intestine, whereas in the colon butyrate inhibits apoptosis and thus increases crypt depth. It was the aim of this study to combine these effects by targeting fat-coated butyrate into the small intestine where it usually does not occur, and to investigate effects on mucosal development and function. Three groups of five pigs were fed 3.6 kg/day of either a low-energy ration [deficit group, 6.6 MJ metabolizable energy (ME)/kg] or a high-energy ration (13.7 MJ ME/kg) that was supplemented with brewing yeast as a source of purines. The third ration was of high energy and contained purines and was additionally supplemented with coated butyrate (13.5 MJ ME/kg; 29 g calcium butyrate/kg). Rations were fed for 5 days. After killing, tissue samples were obtained from the proximal, medial and distal parts of jejunum for histology. Chyme samples were obtained from the ileum of all animals and used for sucrase determination. Villus size was not changed by feeding, but butyrate had an effect on plica height and area mainly in the medial jejunum. Plica area in the butyrate group (4.2 mm(2)) was significantly higher (p <or= 0.01) compared with that of the deficit group (2.3 mm(2)) and high-energy group (2.7 mm(2); p <or= 0.01). For the butyrate group, sucrase activity in the ileum was 119.1 U/ml and thus significantly higher (0.05) compared with the high-energy group (61.7 U/ml) and the deficit group (28.0 U/ml; p <or= 0.001). Targeting butyrate into the small intestine thus improves digestive and absorptive capacities. The mechanism probably is a specific effect on enterocyte mitosis which in turn leads to an increased plica size by crypt fission.

Changes in purine content of tilapia surimi products during processing

Changes in purine-related compounds of tilapia surimi product during processing were investigated. The washing step could, result in about 60% decrease of total purine content in tilapia mince during processing. The main released purine substance was inosine monophosphate. The major reducing effect was conducted in the first 10 min during washing. No significant changes were observed after washing for 20 and 30 min. The lowest total purine content of tilapia surimi product was obtained with repeating the washing step twice. Thus, this procedure could reduce the purine content of tilapia mince from a high purine content level to a middle level. The gel strength of tilapia surimi product increased with increasing washing duration within 30 min. However, tilapia surimi product with a middle purine content and acceptable gel strength might be produced by washing twice in 10 min during processing.

A mRNA determinant of gRNA-directed kinetoplastid editing.

Several mitochondrial mRNAs of the kinetoplastid protozoa do not encode a functional open reading frame until they have been edited through the addition or deletion of U nucleotides at specific sites. Genetic information specifying the location and extent of editing is present on guide RNAs (gRNAs). The sequence adjacent to most mRNA editing sites has a high purine content which previously has been proposed to facilitate the editing reaction through base-pairing to a poly(U) tail at the 3' end of the gRNA. We demonstrate here that gRNA binding alone is insufficient to create an editing site and that the mRNA sequence near an editing site is an additional determinant affecting the efficiency of the reaction.

Hypermutation generating the sheep immunoglobulin repertoire is an antigen-independent process

Somatic hypermutation of light chain V genes during development of B cells in sheep ileal Peyer's patches was studied i n three experimental conditions: in sterile fragments of the ileum surgically isolated from the gut during fetal life, in germ-free sheep, and in animals thymectomized during early fetal life. The somatic mutation pattern was found identical to control tissues in all three experiments. The same age-dependent amount of mutations, a higher than theoretical R/S ratio in complementarity-determining regions (CDRs), and a similar clustering of mutations in CDRs were observed. The mechanism, as estimated from the silent mutation pattern, appears to target mutations to CDRs; moreover, the major Vλ genes have a specific codon usage with a high purine content at the first two bases of the codons and a low content at the third position, which, together with a specific targeting of mutations to purines, favors replacement mutations in CDRs.

Three stages in the evolution of the genetic code

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.

Two cellular proteins bind specifically to a purine-rich sequence necessary for the destabilization function of a c-fos protein-coding region determinant of mRNA instability.

The c-fos proto-oncogene mRNA is rapidly degraded within minutes after its appearance in the cytoplasm of growth factor-stimulated mammalian fibroblasts. At least two functionally independent sequence elements are responsible for the lability of c-fos mRNA. One of these determinants is located within a 0.32-kb sequence present in the protein-coding region. We demonstrate by gel mobility shift experiments and UV cross-linking that at least two protein factors specifically interact with a 56-nucleotide purine-rich sequence located at the 5' end of the 0.32-kb coding region determinant of mRNA instability (CRDI). One protein is predominantly associated with the polysomes, while the other is detected in the post-ribosomal supernatant. Sequence comparison of members of the fos gene family revealed that the high purine content of the protein-binding region is conserved through evolution. Deletion of this region from the 0.32-kb CRDI severely impedes its function as an RNA-destabilizing element. Our results suggest that binding of the two proteins to the purine-rich sequence may participate in the rapid mRNA decay mediated by this 0.32-kb c-fos CRDI.

Two cellular proteins bind specifically to a purine-rich sequence necessary for the destabilization function of a c-fos protein-coding region determinant of mRNA instability.

The c-fos proto-oncogene mRNA is rapidly degraded within minutes after its appearance in the cytoplasm of growth factor-stimulated mammalian fibroblasts. At least two functionally independent sequence elements are responsible for the lability of c-fos mRNA. One of these determinants is located within a 0.32-kb sequence present in the protein-coding region. We demonstrate by gel mobility shift experiments and UV cross-linking that at least two protein factors specifically interact with a 56-nucleotide purine-rich sequence located at the 5' end of the 0.32-kb coding region determinant of mRNA instability (CRDI). One protein is predominantly associated with the polysomes, while the other is detected in the post-ribosomal supernatant. Sequence comparison of members of the fos gene family revealed that the high purine content of the protein-binding region is conserved through evolution. Deletion of this region from the 0.32-kb CRDI severely impedes its function as an RNA-destabilizing element. Our results suggest that binding of the two proteins to the purine-rich sequence may participate in the rapid mRNA decay mediated by this 0.32-kb c-fos CRDI.

Trehalase Deficiency

Perspectives in nutrition suggest a greater use of single-cell proteins in the future. The problems of a high purine content and of potential allergens have been solved by technology. The single-cell proteins may contain trehalose, the absorption of which by the human intestine necessitates prior hydrolysis by trehalase, a specific brush-border disaccharidase. The enzymatic analysis of 100 intestinal biopsies discovered 2 cases of very low trehalase level, with an expected clinical intolerance to even small doses of trehalose. It is concluded that tolerance to high doses of trehalose should be excellent in about 98% of healthy people.