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Congenital disorders of glycosylation (CDG) are a group of more than 100 rare genetic disorders characterized by impaired glycosylation of proteins and lipids. The clinical presentation of CDG varies tremendously, from single-organ to multi-organ involvement and from prenatal death to a normal adult phenotype. In this case study, we report a large consanguineous family with multiple children suffering from cerebral palsy, seizure, developmental and epileptic encephalopathy, and global developmental delay. Whole-exome sequencing (WES) analysis revealed a homozygous variant in the UDP-glucose dehydrogenase (UGDH) gene (c.950G>A; p.R317Q) which segregates with the familial phenotype with a plausible autosomal recessive mode of inheritance, indicating a potential disease-causing association. The UGDH gene encodes the UDP-glucose dehydrogenase, a key enzyme in the synthesis of specific extracellular matrix constituents (proteoglycans and glycolipids) involved in neural migration and connectivity during early brain development. Many pathogenic mutations of UGDH have been reported in recent literature works. However, the variant identified in this study has been observed only in the Saudi population (13 families) and not in any other ethnic background, suggesting that it may be an ancient founder mutation. [ABSTRACT FROM AUTHOR]

Congenital disorders of glycosylation (CDG) are a group of more than 100 rare genetic disorders characterized by impaired glycosylation of proteins and lipids. The clinical presentation of CDG varies tremendously, from single-organ to multi-organ involvement and from prenatal death to a normal adult phenotype. In this case study, we report a large consanguineous family with multiple children suffering from cerebral palsy, seizure, developmental and epileptic encephalopathy, and global developmental delay. Whole-exome sequencing (WES) analysis revealed a homozygous variant in the UDP-glucose dehydrogenase (UGDH) gene (c.950G>A; p.R317Q) which segregates with the familial phenotype with a plausible autosomal recessive mode of inheritance, indicating a potential disease-causing association. The UGDH gene encodes the UDP-glucose dehydrogenase, a key enzyme in the synthesis of specific extracellular matrix constituents (proteoglycans and glycolipids) involved in neural migration and connectivity during early brain development. Many pathogenic mutations of UGDH have been reported in recent literature works. However, the variant identified in this study has been observed only in the Saudi population (13 families) and not in any other ethnic background, suggesting that it may be an ancient founder mutation.

Abstract Background The importance of uridine 5′-diphosphate glucose (UDP-G) synthesis and degradation on carbon (C) partitioning has been indicated in several studies of plant systems, whereby the kinetic properties and abundance of involved enzymes had a significant effect upon the volume of C moving into the hemicellulose, cellulose and sucrose pools. In this study, the expression of 136 genes belonging to 32 gene families related to UDP-G metabolism was studied in 3 major sugarcane organs (including leaf, internode and root) at 6 different developmental stages in 2 commercial genotypes. Results Analysis of the genes associated with UDP-G metabolism in leaves indicated low expression of sucrose synthase, but relatively high expression of invertase genes, specifically cell-wall invertase 4 and neutral acid invertase 1–1 and 3 genes. Further, organs that are primarily responsible for sucrose synthesis or bioaccumulation, i.e., in source organs (mature leaves) and storage sink organs (mature internodes), had very low expression of sucrose, cellulose and hemicellulose synthesis genes, specifically sucrose synthase 1 and 2, UDP-G dehydrogenase 5 and several cellulose synthase subunit genes. Gene expression was mostly very low in both leaf and mature internode samples; however, leaves did have a comparatively heightened invertase and sucrose phosphate synthase expression. Major differences were observed in the transcription of several genes between immature sink organs (roots and immature internodes). Gene transcription favoured utilisation of UDP-G toward insoluble and respiratory pools in roots. Whereas, there was comparatively higher expression of sucrose synthetic genes, sucrose phosphate synthase 1 and 4, and comparatively lower expression of many genes associated with C flow to insoluble and respiratory pools including myo-Inositol oxygenase, UDP-G dehydrogenase 4, vacuolar invertase 1, and several cell-wall invertases in immature internodes. Conclusion This study represents the first effort to quantify the expression of gene families associated with UDP-G metabolism in sugarcane. Transcriptional analysis displayed the likelihood that C partitioning in sugarcane is closely related to the transcription of genes associated with the UDP-G metabolism. The data presented may provide an accurate genetic reference for future efforts in altering UDP-G metabolism and in turn C partitioning in sugarcane.

ABSTRACT Polymyxins are the last-line antibiotics used to treat Gram-negative pathogens. Thus, the discovery and biochemical characterization of the resistance genes against polymyxins are urgently needed for diagnosis, treatment, and novel antibiotic design. Herein, we report novel polymyxin-resistance genes identified from sediment and seawater microbiome. Despite their low sequence identity against the known pmrE and pmrF, they show in vitro activities in UDP-glucose oxidation and l-Ara4N transfer to undecaprenyl phosphate, respectively, which occur as the part of lipid A modification that leads to polymyxin resistance. The expression of pmrE and pmrF also showed substantially high MICs in the presence of vanadate ions, indicating that they constitute polymyxin resistomes. IMPORTANCE Polymyxins are one of the last-resort antibiotics. Polymyxin resistance is a severe threat to combat multidrug-resistant pathogens. Thus, up-to-date identification and understanding of the related genes are crucial. Herein, we performed structure-guided sequence and activity analysis of five putative polymyxin-resistant metagenomes. Despite relatively low sequence identity to the previously reported polymyxin-resistance genes, at least four out of five discovered genes show reactivity essential for lipid A modification and polymyxin resistance, constituting antibiotic resistomes.

[Display omitted] • Metabolic bottlenecks were identified using Kinetic and stoichiometric models. • Gene target selection was successfully guided by in silico analysis. • Genetic modification in Xanthomonas produced a higher xanthan gum yield. • Overexpression of the UDPG-deH enzyme was proven to enhance xanthan gum production. • Recombinant strain increased about 50% volumetric productivity of xanthan gum. Current efforts to improve xanthan gum (XG) production by Xanthomonas have focused on the growth medium, operating parameters, and downstream steps. However, a key aspect is the development of optimal strains. The present work aimed to investigate the formation of XG monomers, using kinetic and stoichiometric models to identify possible bottlenecks, and to engineer a recombinant strain to overcome such limitations. The galU and ugd genes involved in the biosynthesis of the UDP-glucose and UDP-glucuronic acid monomers were overexpressed in Xanthomonas campestris pv. campestris. The strains were cultivated in shake flasks and bioreactor. As predicted by in silico analysis, overexpression of the ugd gene resulted in a significant increase in gum synthesis, up to 50% higher volumetric productivity in the bioreactor. To a lesser extent, galU overexpression was also shown to improve product formation. These findings validated the hypothesis that metabolic engineering of the monomer biosynthesis can enhance XG production. [ABSTRACT FROM AUTHOR]

UDP-glucose dehydrogenase (UGD; EC1.1.1.22) is a NAD+-dependent enzyme that catalyzes the two-fold oxidation of UDP-glucose (UDP-Glc) to produce UDP-glucuronic acid and plays an important role in plant cell wall synthesis. A total of 42 UGD genes from four Gossypium genomes including G. hirsutum, G. arboretum, G. barbadense, and G. raimondii were identified and found that the UGD gene family has conservative evolution patterns in gene structure and protein domain. The growth of fibers can be effectively promoted after adding the UDP-Glc to the medium, and the GhUGD gene expression enhanced. In addition, the transgenic Arabidopsis lines over-expressing GH_D12G1806 had longer root lengths and higher gene expression level than the wild-type plants of Columbia-0. These results indicated that UGD may play important roles in cotton fiber development and has a guiding significance for dissecting fiber development mechanism.

UDP-glucose dehydrogenase (UGD; EC1.1.1.22) is a NAD+-dependent enzyme that catalyzes the two-fold oxidation of UDP-glucose (UDP-Glc) to produce UDP-glucuronic acid and plays an important role in plant cell wall synthesis. A total of 42 UGD genes from four Gossypium genomes including G. hirsutum , G. arboretum , G. barbadense , and G. raimondii were identified and found that the UGD gene family has conservative evolution patterns in gene structure and protein domain. The growth of fibers can be effectively promoted after adding the UDP-Glc to the medium, and the GhUGD gene expression enhanced. In addition, the transgenic Arabidopsis lines over-expressing GH_D12G1806 had longer root lengths and higher gene expression level than the wild-type plants of Columbia-0. These results indicated that UGD may play important roles in cotton fiber development and has a guiding significance for dissecting fiber development mechanism. [ABSTRACT FROM AUTHOR]

In order to increase content of glucuronic acid in the exopolysaccharide (EPS) and its flocculating activity, an UDP-glucose dehydrogenase gene was overexpressed in Lipomyces starkeyi V19. The obtained U9 strain could produce 62.1 ± 1.2 g/l EPS while the V19 strain only produced 53.5 ± 1.3 g/l EPS. The compositions of monosaccharides (mannose, glucuronic acid and galactose) in the purified EPS (U9-EPS) from the U9 strain contained 3.79:1:5.52 while those in the purified EPS (V19-EPS) were 3.94:1:6.29. The flocculation rate of the U9-EPS on kaolin clay reached 87.9%, which was significantly higher than that (74.7%) of the V19-EPS while the decolorization rate of Congo Red (CR) by the U9-EPS reached 94.3%, which was significantly higher than that of CR by the V19-EPS (86.23%). The results showed that the purified bioflocculant U9-EPS had effective flocculation of kaolin clay. The U9-EPS also had high ability to flocculate the polluted river water and decolorize Congo red. • Expression of a UDP-glucose dehydrogenase gene increased content of glucuronic acid in the EPS and its flocculating activity. • The obtained U9 strain could produce 62.1 ± 1.2 g/l EPS. • The U9-EPS also had high ability to flocculate the polluted river water and decolorize Congo red. [ABSTRACT FROM AUTHOR]

Maternal dexamethasone decreases the body length of the newborn. However, whether dexamethasone inhibits the development of the growth plate of the fetal long bone is still unknown. Here, we found that lengths of fetal femur and growth plate were both shorter in the fetuses with maternal dexamethasone (0.2 mg/kg.d from gestation day 9 to 20), with a decreased proteoglycan content of the growth plate in the fetal rat. Notable decreases in both the gene expression and H3K9 acetylation of UDP‐glucose dehydrogenase (Ugdh) gene, which codes a key enzyme in the proteoglycan biosynthesis in the chondrocyte, were also observed. Meanwhile, up‐regulation of glucocorticoid receptor (GR), specific protein 3 (Sp3), and histone deacetylase 1 (Hdac1) gene expression were detected in the fetal growth plate. Similar changes were also observed in the chondrogenic rat bone marrow stromal cells (BMSCs) with excessive exogenous dexamethasone. However, antagonizing GR with RU486 and silencing Hdac1 or Sp3 with specific siRNAs could all stimulate the H3K9 acetylation and gene expression of Ugdh previously inhibited by dexamethasone. Meanwhile, dexamethasone also induced the nuclear translocation of GR, which further directly bound to the Ugdh promoter and interacted with HDAC1 and Sp3, respectively. Collectively, our study revealed that maternal dexamethasone induced the direct binding of GR to the Ugdh promoter of the chondrocyte in the rat fetal growth plate, which recruited HDAC1 and Sp3, induced deacetylation of the H3K9, and subsequently inhibited Ugdh gene expression. Such changes further led to attenuated proteoglycan synthesis in the developing chondrocyte and therefore disrupted the development of growth plate and fetal long bone. [ABSTRACT FROM AUTHOR]

Maternal dexamethasone decreases the body length of the newborn. However, whether dexamethasone inhibits the development of the growth plate of the fetal long bone is still unknown. Here, we found that lengths of fetal femur and growth plate were both shorter in the fetuses with maternal dexamethasone (0.2 mg/kg.d from gestation day 9 to 20), with a decreased proteoglycan content of the growth plate in the fetal rat. Notable decreases in both the gene expression and H3K9 acetylation of UDP-glucose dehydrogenase (Ugdh) gene, which codes a key enzyme in the proteoglycan biosynthesis in the chondrocyte, were also observed. Meanwhile, up-regulation of glucocorticoid receptor (GR), specific protein 3 (Sp3), and histone deacetylase 1 (Hdac1) gene expression were detected in the fetal growth plate. Similar changes were also observed in the chondrogenic rat bone marrow stromal cells (BMSCs) with excessive exogenous dexamethasone. However, antagonizing GR with RU486 and silencing Hdac1 or Sp3 with specific siRNAs could all stimulate the H3K9 acetylation and gene expression of Ugdh previously inhibited by dexamethasone. Meanwhile, dexamethasone also induced the nuclear translocation of GR, which further directly bound to the Ugdh promoter and interacted with HDAC1 and Sp3, respectively. Collectively, our study revealed that maternal dexamethasone induced the direct binding of GR to the Ugdh promoter of the chondrocyte in the rat fetal growth plate, which recruited HDAC1 and Sp3, induced deacetylation of the H3K9, and subsequently inhibited Ugdh gene expression. Such changes further led to attenuated proteoglycan synthesis in the developing chondrocyte and therefore disrupted the development of growth plate and fetal long bone. [ABSTRACT FROM AUTHOR]

Autophagy is an essential degradation and recycling process that maintains cellular homeostasis during stress or nutrient deprivation. However, certain types of tumors such as pancreatic cancers can circumvent autophagy inhibition to sustain growth. The mechanism that autophagy-deficient pancreatic ductal adenocarcinoma (PDAC) uses to grow under nutrient deprivation is poorly understood. Our data show that nutrient deprivation in PDAC results in UDP-glucose dehydrogenase (UGDH) degradation, which is dependent on autophagic cargo receptor sequestosome 1 (p62). Moreover, we demonstrate that accumulated UGDH is indispensable for autophagy-deficient PDAC cells proliferation by promoting hyaluronic acid (HA) synthesis upon energy deprivation. Using an orthotopic mouse model of PDAC, we find that inhibition of HA synthesis by targeting UGDH in PDAC reduces tumor weight. Thus, the combined inhibition of HA and autophagy might be an attractive strategy for PDAC treatment. [Display omitted] • UGDH is degraded by autophagic process dependent on p62 • Autophagy-deficient PDAC upregulates UGDH to promote hyaluronic acid synthesis • Hyaluronic acid maintains autophagy-deficient PDAC proliferation under nutrient starvation Fan et al. report that UGDH is degraded by p62-mediated autophagy, and it accumulates in autophagy-deficient PDAC. UGDH increases hyaluronic acid (HA) synthesis to sustain proliferation of autophagy-deficient PDAC. The combined inhibition of UGDH/HA with autophagy results in reduction of PDAC growth. [ABSTRACT FROM AUTHOR]

Uridine diphosphate-glucose dehydrogenase (UGD) is an enzyme that produces uridine diphosphate-glucuronic acid (UDP-GlcA), which is an intermediate in glycosaminoglycans (GAGs) production pathways. GAGs are generally extracted from animal tissues. Efforts to produce GAGs in a safer way have been conducted by constructing artificial biosynthetic pathways in heterologous microbial hosts. This work characterizes novel enzymes with potential for UDP-GlcA biotechnological production. The UGD enzymes from Zymomonas mobilis (ZmUGD) and from Lactobacillus johnsonii (LbjUGD) were expressed in Escherichia coli. These two enzymes and an additional eukaryotic one from Capra hircus (ChUGD) were also expressed in Saccharomyces cerevisiae strains. The three enzymes herein studied represent different UGD phylogenetic groups. The UGD activity was evaluated through UDP-GlcA quantification in vivo and after in vitro reactions. Engineered E. coli strains expressing ZmUGD and LbjUGD were able to produce in vivo 28.4 µM and 14.9 µM UDP-GlcA, respectively. Using S. cerevisiae as the expression host, the highest in vivo UDP-GlcA production was obtained for the strain CEN.PK2-1C expressing ZmUGD (17.9 µM) or ChUGD (14.6 µM). Regarding the in vitro assays, under the optimal conditions, E. coli cell extract containing LbjUGD was able to produce about 1800 µM, while ZmUGD produced 407 µM UDP-GlcA, after 1 h of reaction. Using engineered yeasts, the in vitro production of UDP-GlcA reached a maximum of 533 µM using S. cerevisiae CEN.PK2-1C_pSP-GM_LbjUGD cell extract. The UGD enzymes were active in both prokaryotic and eukaryotic hosts, therefore the genes and expression chassis herein used can be valuable alternatives for further industrial applications.

The tumor microenvironment is becoming a crucial factor in determining the aggressiveness of neoplastic cells. The glycosaminoglycan hyaluronan is one of the principal constituents of both the tumor stroma and the cancer cell surfaces, and its accumulation can dramatically influence patient survival. Hyaluronan functions are dictated by its ability to interact with several signaling receptors that often activate pro‐angiogenic and pro‐tumorigenic intracellular pathways. Although hyaluronan is a linear, non‐sulfated polysaccharide, and thus lacks the ability of the other sulfated glycosaminoglycans to bind and modulate growth factors, it compensates for this by the ability to form hyaluronan fragments characterized by a remarkable variability in length. Here, we will focus on the role of both high and low molecular weight hyaluronan in controlling the hallmarks of cancer cells, including cell proliferation, migration, metabolism, inflammation, and angiogenesis. We will critically assess the multilayered regulation of HAS2, the most critical hyaluronan synthase, and its role in cancer growth, metabolism, and therapy. [ABSTRACT FROM AUTHOR]

Polysaccharide peptides (or protein-bound polysaccharides, PSPs) are commonly found in mushrooms and plants and possess important nutritional properties and health benefits. The pathogenic bacterium Streptococcus zooepidemicus does not inherently produce PSPs but secretes the capsular polysaccharide hyaluronan. However, in a previous investigation of the catalytic mechanism of UDP-glucose dehydrogenase (UGDH), a PSP of peptide-bound hyaluronan was found to be produced by S. zooepidemicus through the in vivo expression of a mutant of the gene encoding UGDH. In the present study, this hyaluronan-derived PSP was structurally characterized by FT-IR, NMR, and high-performance liquid chromatography-mass spectrometry (HPLC-MS), and the data confirmed that the polysaccharide backbone, hyaluronan, is covalently bound to the side-chain peptides via an amide linkage. More importantly, the bacterial production of a PSP via this genetic modification method should inspire further research on the in vitro enzymatic synthesis of PSPs or even naturally occurring polysaccharide derivatives and may provide a theoretical foundation for investigating the in vivo synthetic mechanism of PSPs. Image 1 • Streptococcus zooepidemicus inherently secretes the polysaccharide hyaluronan. • A mutant strain of S. zooepidemicus produces a polysaccharide peptide (PSP). • This artificial PSP is verified to be a hyaluronan-based derivative. • Production of PSP via this genetic modification is novel and illuminating. [ABSTRACT FROM AUTHOR]

Highlights • UHPLC-DAD-LTQ-Orbitrap-MS method for metabolite characterization of idelalisib. • 14 metabolites were identified. • Metabolic pathways was proposed. • Species-specific metabolic difference was disclosed between animals and human. Abstract Idelalisib acts as a phosphoinositide 3 kinase inhibitor, which has been approved by the US FDA for the treatment of certain hematological malignancies. The aim of this study is to profile the metabolites of idelalisib in the liver microsomes of mouse, rat, rabbit, dog, monkey and human. Idelalisib at the concentration of 20 μM was incubated with the liver microsomes in the presence of NADPH, GSH and UDPGA. The incubation samples were analyzed by ultra-high performance liquid chromatography coupled with diode array detector and linear ion trap-orbitrap tandem mass spectrometer (UHPLC-DAD-LTQ-Orbitrap-MS), and the post-acquisition data was processed by Metworks software. Under the current experimental conditions, a total of 14 metabolites were detected. The structures of the metabolites were characterized based on their accurate masses, fragmental ions and retention times. Our results suggested the following: 1) idelalisib was prone to oxidative defluorination to give rise to desfluoroidelalisib (M13). This metabolite was reactive in nature as its corresponding GSH conjugate was detected (M4). Except GSH conjugation, this metabolite can further undergo oxygenation (M7 and M14), and glucuronidation (M3); 2) oxygenation was the major metabolic pathway in liver microsomes, leading to the metabolite M10 in all test species; 3) idelalisib can be directly conjugated with glucuronide to form N +-glucuronide (M1). Species-specific metabolic difference was observed between animals and human and rat and dog have closer metabolic profiles to human compared with other animal species. [ABSTRACT FROM AUTHOR]

UDP-glucose-dehydrogenase (UGDH) synthesizes UDP-glucuronic acid. It is involved in epirubicin detoxification and hyaluronan synthesis. This work aimed to evaluate the effect of UGDH knockdown on epirubicin response and hyaluronan metabolism in MDA-MB-231 breast cancer cells. Additionally, the aim was to determine UGDH as a possible prognosis marker in breast cancer. We studied UGDH expression in tumors and adjacent tissue from breast cancer patients. The prognostic value of UGDH was studied using a public Kaplan–Meier plotter. MDA-MB-231 cells were knocked-down for UGDH and treated with epirubicin. Epirubicin-accumulation and apoptosis were analyzed by flow cytometry. Hyaluronan-coated matrix and metabolism were determined. Autophagic-LC3-II was studied by Western blot and confocal microscopy. Epirubicin accumulation increased and apoptosis decreased during UGDH knockdown. Hyaluronan-coated matrix increased and a positive modulation of autophagy was detected. Higher levels of UGDH were correlated with worse prognosis in triple-negative breast cancer patients that received chemotherapy. High expression of UGDH was found in tumoral tissue from HER2--patients. However, UGDH knockdown contributes to epirubicin resistance, which might be associated with increases in the expression, deposition and catabolism of hyaluronan. The results obtained allowed us to propose UGDH as a new prognostic marker in breast cancer, positively associated with development of epirubicin resistance and modulation of extracellular matrix.

In vitro experiments suggest that glycosaminoglycans (GAGs) and the proteins to which they are attached (proteoglycans) are important for modulating growth factor signaling. However, in vivo evidence to support this view has been lacking, in part because mutations that disrupt the production of GAG polymers and the core proteins have not been available. Here we describe the identification and characterization of Drosophila mutants in the suppenkasper (ska) gene. The ska gene encodes UDP-glucose dehydrogenase which produces glucuronic acid, an essential component for the synthesis of heparan and chondroitin sulfate. ska mutants fail to put heparan side chains on proteoglycans such as Syndecan. Surprisingly, mutant embryos produced by germ-line clones of this general metabolic gene exhibit embryonic cuticle phenotypes strikingly similar to those that result from loss-of-function mutations in genes of the Wingless (Wg) signaling pathway. Zygotic loss of ska leads to reduced growth of imaginal discs and pattern defects similar to wg mutants. In addition, genetic interactions of ska with wg and dishevelled mutants are observed. These data demonstrate the importance of proteoglycans and GAGs in Wg signaling in vivo and suggest that Wnt-like growth factors may be particularly sensitive to perturbations of GAG biosynthesis.

Plant uridine diphosphate (UDP)-glucosyltransferases (UGT) catalyze the glucosylation of xenobiotic, endogenous substrates and phytotoxic agents produced by pathogens such as mycotoxins. The Bradi5g03300 UGT-encoding gene from the model plant Brachypodium distachyon was previously shown to confer tolerance to the mycotoxin deoxynivalenol (DON) through glucosylation into DON 3- O -glucose (D3G). This gene was shown to be involved in early establishment of quantitative resistance to Fusarium Head Blight, a major disease of small-grain cereals. In the present work, using a translational biology approach, we identified and characterized a wheat candidate gene, Traes_2BS_14CA35D5D , orthologous to Bradi5g03300 on the short arm of chromosome 2B of bread wheat (Triticum aestivum L.). We showed that this UGT-encoding gene was highly inducible upon infection by a DON-producing Fusarium graminearum strain while not induced upon infection by a strain unable to produce DON. Transformation of this wheat UGT-encoding gene into B. distachyon revealed its ability to confer FHB resistance and root tolerance to DON as well as to potentially conjugate DON into D3G in planta and its impact on total DON reduction. In conclusion, we provide a UGT-encoding candidate gene to include in selection process for FHB resistance. [ABSTRACT FROM AUTHOR]

The enzyme UDP-glucose dehydrogenase (UGD) competes with sucrose-phosphate synthase for the common photosynthesis product UDP-glucose. Sucrose-phosphate synthase is part of a pathway for the export of sucrose from source leaves to neighboring cells or the phloem. UGD is a central enzyme in a pathway for many nucleotide sugars used in local cell wall biosynthesis. Here, we identify a highly conserved phosphorylation site in UGD which is readily phosphorylated by MAP-kinase 3 in Arabidopsis. Phosphorylation occurs at a surface-exposed extra loop in all plant UGDs that is absent in UGDs from bacteria or animals. Phosphorylated sucrose-phosphate synthase is shifted to an inactive form which we did not measure for phosphorylated UGD. Plant UGDs have an extra loop which is phosphorylated by AtMPK3. Phosphorylation is not causing a reduction of UGD activity as found for the competitor enzymes and thus sets a preference for maintaining UDP-sugars at a constant level to prioritize cell wall biosynthesis. [ABSTRACT FROM AUTHOR]

The effect of sodium chloride (NaCl) on pullulan production by batch culture of Aureobasidium pullulans CCTCC M 2012259 was investigated. NaCl at 3 g/L improved the pullulan titer by 26.7% but reduced the molecular weight of pullulan to only 46.8% of that obtained in the control without NaCl. In order to elucidate the physiological mechanism underlying the effect of NaCl on pullulan production, assays of key enzyme activity, gene expression, energy metabolism, and intracellular uridine diphosphate glucose (UDP-glucose) content were performed. Results indicated that NaCl increased the activities of α-phosphoglucose mutase and glucosyltransferase involved in pullulan biosynthesis, increased the activities of α-amylase being responsible for pullulan degradation, upregulated the transcriptional levels of pgm1, fks, and amy2 genes, enhanced the driving force for ATP supply, and helped to maintain intracellular UDP-glucose at a high level in A. pullulans CCTCC M 2012259. All these results illuminate the reason by which NaCl increases pullulan titer but reduces the molecular weight of pullulan. [ABSTRACT FROM AUTHOR]

6-Thiopurine (6TP) is an actively prescribed drug in the treatment of various diseases ranging from Crohn’s disease and other inflammatory diseases to acute lymphocytic leukemia and non-Hodgkin’s leukemia. While 6TP has beneficial therapeutic uses, severe toxicities are also reported with its use, such as jaundice and liver toxicity. While numerous investigations into the mode in which toxicity originates has been undertaken. None have investigated the effects of inhibition towards UDP-Glucose Dehydrogenase (UDPGDH), an oxidative enzyme responsible for UDP-glucuronic acid (UDPGA) formation or UDP-Glucuronosyl transferase (UGT1A1), which is responsible for the conjugation of bilirubin with UDPGA for excretion. Failure to excrete bilirubin leads to jaundice and liver toxicity. We proposed that either 6TP or its primary oxidative excretion metabolites inhibit one or both of these enzymes, resulting in the observed toxicity from 6TP administration. Inhibition analysis of these purines revealed that 6-thiopurine has weak to no inhibition towards UDPGDH with a K i of 288 μM with regard to varying UDP-glucose, but 6-thiouric (primary end metabolite, fully oxidized at carbon 2 and 8, and highly retained by the body) has a near six-fold increased inhibition towards UDPGDH with a K i of 7 μM. Inhibition was also observed by 6-thioxanthine (oxidized at carbon 2) and 8-OH-6TP with K i values of 54 and 14 μM, respectively. Neither 6-thiopurine or its excretion metabolites were shown to inhibit UGT1A1. Our results show that the C2 and C8 positions of 6TP are pivotal in said inhibition towards UDPGDH and have no effect upon UGT1A1, and that blocking C8 could lead to new analogs with reduced, if not eliminated jaundice and liver toxicities. [ABSTRACT FROM AUTHOR]

This perspective paper focuses on the most recent results suggesting a potential role for UDP-Glucose as a signaling molecule in plants. In animals, UDP-Glucose is wellestablished as an extracellular signaling molecule that is sensed by G-protein coupled receptors, activating several downstream defense mechanisms. Recent studies have shown that abnormal growth occurred in both vegetative and reproductive tissue of plants with reduced UDP-Glucose levels, and this could be rescued by exogenous UDP-Glucose. In plants with increased biomass accumulation, the genes involved in UDP-Glucose production were up-regulated. However, excessive endogenous accumulation of UDP-Glucose induced programmed cell death (PCD), and this could also be obtained by exogenous UDP-Glucose application. Plants with decreased UDPglucose were insensitive to pathogen induced PCD. We speculate that UDP-Glucose acts as an extracellular signaling molecule in plants, and that it may be perceived as a damage-associated molecular pattern. [ABSTRACT FROM AUTHOR]

The hepatic activities of uridine diphosphate glucuronosyltransferase ( UGT) and sulfotransferase ( SULT) of male Ross 708 broiler chickens at the age of 1, 7, 14, 28, and 56 days and male Camborough-29 pigs at the age of 1 day and 2, 5, 10, and 20 weeks were investigated. Glucuronidation and sulfation of 4-nitrophenol were used to evaluate the activities. Porcine hepatic UGT and SULT activities were low at birth, peaked at around 5-10 weeks, and then declined. Both hepatic UGT and SULT activities of chickens were high at hatch and declined. Chicken hepatic UGT activity had a peak at the age of 28 days. Affinity of hepatic SULT to 4-nitrophenol is similar in chickens and pigs, but the affinity of hepatic UGT in pigs was about 10 times higher than that in chickens. 4-nitrophenol was predominantly conjugated by SULT instead of UGT in chicken livers from hatch to day 56. Conversely, hepatic UGT contributed predominantly in 4-nitrophenol conjugation than the SULT in pigs from birth to 20 weeks. Therefore, age has significant impact on hepatic activities of UGT and SULT, and the importance of UGT and SULT on conjugation is different in chickens and pigs. [ABSTRACT FROM AUTHOR]

Uridine diphosphate glucose dehydrogenase (UGDH) plays an important role in biosynthesis of hemicellulose by catalyzing oxidation of UDP-glucose (UDP-Glc) to UDP-glucuronate (UDP-GlcA), a key sugar nucleotide involved in biosynthesis of the plant cell wall. In this study, a UGDH ortholog referred to as LgUGDH was isolated from Larix gmelinii using PCR and rapid amplification of cDNA ends techniques. Real-time PCR shows that the LgUGDH gene was expressed primarily in larch stems in addition to its roots and leaves, and Southern blot analysis indicates that UGDH is encoded by two paralogous genes in L. gmelinii. Overexpression of LgUGDH increased the content of soluble sugars and hemicelluloses and enhanced vegetative growth and cold tolerance in transgenic Arabidopsis thaliana. These results reveal that L. gmelinii UGDH participates in sucrose/polysaccharide metabolism and cell wall biosynthesis and may be a good candidate gene for enhancing plant growth, cold tolerance, and hemicellulose content. [ABSTRACT FROM AUTHOR]

Haloferax volcanii AglM and Halobacterium salinarum VNG1048G are UDP-glucose dehydrogenases involved in N-glycosylation in each species. Despite sharing >60% sequence identity and the ability of VNG1048G to functionally replace AglM in vivo, these proteins behaved differently as salinity changed. Whereas AglM was active in 2-4 M NaCl, VNG1048G lost much of its activity when salinity dropped below 3 M NaCl. To understand the molecular basis of this phenomenon, each protein was examined by size exclusion chromatrography in 2MNaCl. Whereas AglM appeared as a dodecamer, VNG1048G was essentially detected as a dodecamer and a dimer. The specific activity of the VNG1048G dodecamer was only a sixth of that of AglM, while the dimer was inactive. As such, not only was the oligomeric status of VNG1048G affected by lowered salinity, so was the behavior of the individual dodecamer subunits. Analyzing surface-exposed residues in homology models of the two UDP-glucose dehydrogenases revealed the more acidic and less basic VNG1048G surface, further explaining the greater salt-dependence of the Hbt. salinarum enzyme. [ABSTRACT FROM AUTHOR]

Hyaluronic acid (HA), a vital acid mucopolysaccharide, has immense applied value in foodstuffs, medicaments, and cosmetics among others. UDP-glucose dehydrogenase (UGDH, EC 1.1.1.22) is an essential enzyme for HA synthesis. In this study, a UGDH ( Pmu HasB, 45.9 kDa) from Pasteurella multocida CVCC 408 was expressed in Escherichia coli BL21 (DE3). It was purified by two chromatographic columns with a specific activity of 6.58 IU/mg. The optimum pH and temperature were determined to be 10.0 and 37 °C, respectively. The activity was stable across the pH range 6–10, and had a half-life of about 3 h at 45 °C. The estimated apparent K m values for UDP-glucose and NAD + were 0.11 and 0.069 mM, respectively. The results indicated that Pmu HasB was an alkaline and mesophilic UGDH. Pmu HasB and Pmu HasA (HA synthase, HAS) were co-expressed in E . coli BW25113 to obtain a HA high-producing strain pBPAB/BW25113. It produced about 2.39 g/L HA in shake flask by using the method of whole-cell catalysis. Investigation of the different UGDHs on HA synthesis revealed that intracellular UGDH activity and HA total yield of pBPAB/BW25113 (0.15 IU/mg and 5.4 g/L) were higher than from pBPASB/BW25113 (0.013 IU/mg and 2.8 g/L) and pBPAEB/BW25113 (0.010 IU/mg and 2.22 g/L). These results indicated that the activity and stability of UGDH plays a significant role in HA production, and should prove useful for further genetic engineering research with a view to construct other glucuronic acid polysaccharide synthesis pathways. [ABSTRACT FROM AUTHOR]

Objectives: To use permeabilized cells of the fission yeast, Schizosaccharomyces pombe, that expresses human UDP-glucose 6-dehydrogenase (UGDH, EC 1.1.1.22), for the production of UDP-glucuronic acid from UDP-glucose. Results: In cell extracts no activity was detected. Therefore, cells were permeabilized with 0.3 % (v/v) Triton X-100. After washing away all low molecular weight metabolites, the permeabilized cells were directly used as whole cell biocatalyst. Substrates were 5 mM UDP-glucose and 10 mM NAD. Divalent cations were not added to the reaction medium as they promoted UDP-glucose hydrolysis. With this reaction system 5 mM UDP-glucose were converted into 5 mM UDP-glucuronic acid within 3 h. Conclusions: Recombinant permeabilized cells of S. pombe can be used to synthesize UDP-glucuronic acid with 100 % yield and selectivity. [ABSTRACT FROM AUTHOR]

In the Crigler-Najjar type I syndrome, the genetic absence of efficient hepatic glucuronidation of unconjugated bilirubin (UCB) by the uridine 5′-diphospho-glucuronosyltransferase1A1 (UGT1A1) enzyme produces the rise of UCB level in blood. Its entry to central nervous system could generate toxicity and neurological damage, and even death. In the past years, a compensatory mechanism to liver glucuronidation has been indicated in the hepatic cytochromes P450 enzymes (Cyps) which are able to oxidize bilirubin. Cyps are expressed also in the central nervous system, the target of bilirubin toxicity, thus making them theoretically important to confer a protective activity toward bilirubin accumulation and neurotoxicity. We therefore investigated the functional induction (mRNA, EROD/MROD) and the ability to oxidize bilirubin of Cyp1A1, 1A2, and 2A3 in primary astrocytes cultures obtained from two rat brain region (cortex: Cx and cerebellum: Cll). We observed that Cyp1A1 was the Cyp isoform more easily induced by beta-naphtoflavone (βNF) in both Cx and Cll astrocytes, but oxidized bilirubin only after uncoupling by 3, 4,3′,4′-tetrachlorobiphenyl (TCB). On the contrary, Cyp1A2 was the most active Cyp in bilirubin clearance without uncoupling, but its induction was confined only in Cx cells. Brain Cyp2A3 was not inducible. In conclusion, the exposure of astrocytes to βNF plus TCB significantly enhanced Cyp1A1 mediating bilirubin clearance, improving cell viability in both regions. These results may be a relevant groundwork for the manipulation of brain Cyps as a therapeutic approach in reducing bilirubin-induced neurological damage. [ABSTRACT FROM AUTHOR]

Uridine diphosphate-glucose dehydrogenase (UGD, EC1.1.1.22 oxidizes UDP-Glc (UDP-D-glucose) to UDP-GlcA (UDP-Dglucuronate), a critical precursor of cell wall polysaccharides. GbUGD6 from Gossypium barbadense is more highly expressed late in the elongation of cotton fibers (15 d post-anthesis (DPA)) and during the stage of secondary cell wall thickening (30 DPA). Subcellular localization analysis in onion epidermis revealed that fluorescently labeled GbUGD6 protein was distributed throughout the cell membrane, as well as the nucleus and vacuoles. Examination of UGD function in Arabidopsis revealed that the antisense GbUGD6 lines had shorter roots, deferred blossoming, compared to wild-type plants. Activities of associated enzymes were also affected by UGD reduction, and biochemical analysis of cell wall samples showed an increase in cellulose levels and a decrease in UGP-GlcA contents. The results of the present study as well as previous studies on UGD support the conclusion that UGD plays a major role in synthesizing polysaccharides synthesis in the cell wall. [ABSTRACT FROM AUTHOR]

UDP-glucose dehydrogenase ( UDPGDH), UDP- N-acetyl-mannosamine dehydrogenase ( UDPNAMDH) and GDP-mannose dehydrogenase ( GDPMDH) belong to a family of NAD+-linked 4-electron-transfering oxidoreductases called nucleotide diphosphate sugar dehydrogenases ( NDP- SDHs). UDPGDH is an enzyme responsible for converting UDP- d-glucose to UDP- d-glucuronic acid, a product that has different roles depending on the organism in which it is found. UDPNAMDH and GDPMDH convert UDP- N-acetyl-mannosamine to UDP- N-acetyl-mannosaminuronic acid and GDP-mannose to GDP-mannuronic acid, respectively, by a similar mechanism to UDPGDH. Their products are used as essential building blocks for the exopolysaccharides found in organisms like Pseudomonas aeruginosa and Staphylococcus aureus. Few studies have investigated the relationships between these enzymes. This study reveals the relationships between the three enzymes by analysing 229 amino acid sequences. Eighteen invariant and several other highly conserved residues were identified, each serving critical roles in maintaining enzyme structure, coenzyme binding or catalytic function. Also, 10 conserved motifs that included most of the conserved residues were identified and their roles proposed. A phylogenetic tree demonstrated relationships between each group and verified group assignment. Finally, group entropy analysis identified novel conservations unique to each NDP- SDH group, including residue positions critical to NDP-sugar substrate interaction, enzyme structure and intersubunit contact. These positions may serve as targets for future research. Enzymes UDP-glucose dehydrogenase (UDPGDH, ). [ABSTRACT FROM AUTHOR]

• Functional characterization of five different UGDH isoforms in G. uralensis. • Enzyme kinetics study of the isoforms. • Substrate promiscuity exploration of the isoforms. • Molecular docking, MD-Simulation, and binding free energy calculation. Uridine diphosphate glucose dehydrogenase (UGDH) has a crucial role in the synthesis of UDP-glucuronic acid (UDPGA), which is the important sugar donor in the glucuronosylation of bioactive triterpene saponins in the traditional Chinese medicine Glycyrrhiza uralensis Fisch. UGDHs usually exist as isoforms in plants, but knowledge of their unique binding sites and patterns remains largely incomplete. Here, we mined five UGDH isoforms in G. uralensis transcriptome that catalyze the oxidation of UDP-glucose (UDPG) to UDPGA and had different catalytic efficiencies. Molecular modeling and molecular dynamics simulation revealed the potential catalytic residues for the catalytic efficiencies of the isoforms. Moreover, the UGDH isoforms exhibited substrate promiscuity by catalyzing two structurally diverse UDPG derivatives, which was further demonstrated by docking studies. This work gives new insights into the UGDH isoforms involved in the biosynthesis of glucuronides in G. uralensis , and extends the understanding of the versatility of UGDHs. [ABSTRACT FROM AUTHOR]

Polymyxins are the last-line antibiotics used to treat Gram-negative pathogens. Thus, the discovery and biochemical characterization of the resistance genes against polymyxins are urgently needed for diagnosis, treatment, and novel antibiotic design. Herein, we report novel polymyxin-resistance genes identified from sediment and seawater microbiome. Despite their low sequence identity against the known pmrE and pmrF , they show in vitro activities in UDP-glucose oxidation and l-Ara4N transfer to undecaprenyl phosphate, respectively, which occur as the part of lipid A modification that leads to polymyxin resistance. The expression of pmrE and pmrF also showed substantially high MICs in the presence of vanadate ions, indicating that they constitute polymyxin resistomes. IMPORTANCE Polymyxins are one of the last-resort antibiotics. Polymyxin resistance is a severe threat to combat multidrug-resistant pathogens. Thus, up-to-date identification and understanding of the related genes are crucial. Herein, we performed structure-guided sequence and activity analysis of five putative polymyxin-resistant metagenomes. Despite relatively low sequence identity to the previously reported polymyxin-resistance genes, at least four out of five discovered genes show reactivity essential for lipid A modification and polymyxin resistance, constituting antibiotic resistomes.

UDP-glucuronic acid dehydrogenase (UGD) and UDP-xylose synthase (UXS) are the two enzymes responsible for the biosynthesis of UDP-xylose from UDP-glucose. Several UGDs from bacterial sources, which oxidize UDP-glucose to glucuronic acid, have been found and functionally characterized whereas only few reports on bacterial UXS isoforms exist. Rhodothermus marinus, a halothermophilic bacterium commonly found in hot springs, proved to be a valuable source of carbohydrate active enzymes of biotechnological interest, such as xylanases, mannanases, and epimerases. However, no enzymes of R. marinus involved in the biosynthesis or modification of nucleotide sugars have been reported yet. Herein, we describe the cloning and characterization of two putative UGD (RmUGD1 and RmUGD2) and one UXS (RmUXS) isoform from this organism. All three enzymes could be expressed in recombinant form and purified to near homogeneity. UPLC- and NMR-based activity tests showed that RmUGD1 and RmUXS are indeed active enzymes, whereas no enzymatic activity could be detected by RmUGD2. Both RmUGD1 and RmUXS showed a temperature optimum of 60 °C, with almost no loss of activity after 1 h exposure at 70 °C. No metal ions were required for enzymatic activities. Zn ions strongly inhibited both enzymes. RmUGD1 showed higher salt tolerance and had a higher pH optimum than RmUXS. Furthermore, RmUGD1 was inhibited by UDP-xylose at higher concentrations. By coupling recombinant RmUXS and RmUGD1, UDP-xylose could be successfully synthesized directly from UDP-glucose. The high activity of the herein described enzymes make RmUGD1 and RmUXS the first thermo-tolerant biocatalysts for the synthesis of UDP-glucuronic acid and UDP-xylose. [ABSTRACT FROM AUTHOR]

Irinotecan is a major drug in the treatment of advanced colorectal cancer. Its active form is the SN38 metabolite, which is cleared by the biliary route after glucuronidation by uridine diphosphate-glucuronosyltransferase 1A1 ( UGT1A1). UGT1A1 activity exhibits a wide intersubject variability, in part related to UGT1A1 gene polymorphisms. The present review on the impact of the deficient UGT1A1*28 variant on irinotecan efficacy and toxicity was produced by a French joint workgroup comprising the Group of Clinical Onco-pharmacology ( GPCO-Unicancer) and the National Pharmacogenetics Network ( RNPGx). It clearly emerges that for irinotecan doses at least equal to 180 mg/m2, patients homozygous for the UGT1A1*28 allele are at increased risk of developing hematological and/or digestive toxicities. Irinotecan dose reduction is thus recommended in homozygous *28/*28 patients. In addition, this personalized medicine strategy aims to secure high-dose irinotecan administration (≥240 mg/m2) that have proven to be safe in homozygous *1/*1 patients only. The clinical relevance of this test is discussed in terms of treatment efficacy improvement, as increasing the irinotecan dose appears to be safe in patients not bearing a deficient allele. Best execution practices, cost-effectiveness, and result interpretation are discussed with the aim of facilitating the implementation of this analysis in clinical practice. The existence of networks of laboratories performing this test in routine hospital treatment, as in France, offers the prospect of widespread screening, thus guaranteeing equal access to safe treatment and optimized therapy for patients receiving irinotecan-based therapy in advanced colorectal cancer. [ABSTRACT FROM AUTHOR]

Biopolymer Ss of Sphingomonas sanxanigenens strain NX02 is an sphingan that can be extracted using a small quantity of acid, which is a low cost extraction process. A UDP-glucose dehydrogenase gene ( ugdG), related to Ss biosynthesis, was cloned from S. sanxanigenens NX02 and expressed in Escherichia coli. It encoded a 454-residue protein of 48.2 kDa. The deduced amino acid sequence had 77% identity with UDP-glucose dehydrogenase (UgdG) from Sphingomonas sp. KC8, and 73% identity with UgdG from Sphingomonas elodea ATCC31461. Purified recombinant UgdG had maximum activity at 35°C and pH 8.0, with K values of 0.47 and 0.38 mM for UDP-glucose and NAD, respectively. Overexpression of the ugdG gene in S. sanxanigenens resulted in increased (14.9 ± 0.5)% Ss production and higher fermentation broth viscosity. Furthermore, the weight-average molecular weight of polymer Ss from the recombinant strain was (5.3 ± 0.16)% higher and the viscosity was (74 ± 0.15)% higher than those from the WT strain at a shear rate of 1 rev/min. [ABSTRACT FROM AUTHOR]

Haloferax volcanii AglM and Halobacterium salinarum VNG1048G are UDP-glucose dehydrogenases involved in N-glycosylation in each species. Despite sharing >60% sequence identity and the ability of VNG1048G to functionally replace AglM in vivo, these proteins behaved differently as salinity changed. Whereas AglM was active in 2–4 M NaCl, VNG1048G lost much of its activity when salinity dropped below 3 M NaCl. To understand the molecular basis of this phenomenon, each protein was examined by size exclusion chromatrography in 2 M NaCl. Whereas AglM appeared as a dodecamer, VNG1048G was essentially detected as a dodecamer and a dimer. The specific activity of the VNG1048G dodecamer was only a sixth of that of AglM, while the dimer was inactive. As such, not only was the oligomeric status of VNG1048G affected by lowered salinity, so was the behavior of the individual dodecamer subunits. Analyzing surface-exposed residues in homology models of the two UDP-glucose dehydrogenases revealed the more acidic and less basic VNG1048G surface, further explaining the greater salt-dependence of the Hbt. salinarum enzyme.

Background & Aims Bilirubin has potent antioxidant properties in vitro and raised serum levels have been associated with lower rates of respiratory disease. The enzyme uridine diphosphate glucuronosyltransferase polypeptide 1A1 (UGT1A1) is solely responsible for clearing bilirubin from the blood and homozygosity for seven thymine-adenine (TA) repeats in the TATA box regulatory element of the UGT1A1 gene underlies a mild hereditary unconjugated hyperbilirubinaemia (Gilbert’s syndrome). Our aim was to investigate whether this genetic variation is associated with differences in respiratory health. Methods The relationship between the promoter genotype underlying Gilbert’s syndrome ( UGT1A1 rs8175347 [TA]7/7) and respiratory outcomes assessed at ages 43, 53, and 60–64 were examined in 2190 members of the 1946 British birth cohort. Results The (TA)7/7 genotype, present in 9% of the cohort, was associated with higher forced expiratory volume (FEV1) and forced vital capacity (FVC). The relationship was strongest for heavy smokers (⩾20 cigarettes per day) at age 53 with mean FEV1 409 ml higher (191 to 627; p <0.001) and mean FVC 530 ml higher (95% CI 262–798; p <0.001) for UGT1A1 (TA)7/7 Gilbert’s syndrome participants than for all others, indicating a protection from the pulmonary consequences of heavy smoking. The odds of respiratory disease (chronic obstructive pulmonary disease, self-reported asthma, or prescription of respiratory drugs) were half in those with Gilbert’s syndrome genotype (odds ratio 0.49 [95% CI 0.39–0.74]; p <0.001) compared to those without this genotype. Conclusions Genetically raised unconjugated serum bilirubin is associated with higher adult respiratory function and protection from respiratory disease. [ABSTRACT FROM AUTHOR]

Synthetic ways towards uridine 5′-diphosphate (UDP)-xylose are scarce and not well established, although this compound plays an important role in the glycobiology of various organisms and cell types. We show here how UDP-glucose 6-dehydrogenase (hUGDH) and UDP-xylose synthase 1 (hUXS) from Homo sapiens can be used for the efficient production of pure UDP-α-xylose from UDP-glucose. In a mimic of the natural biosynthetic route, UDP-glucose is converted to UDP-glucuronic acid by hUGDH, followed by subsequent formation of UDP-xylose by hUXS. The nicotinamide adenine dinucleotide (NAD+) required in the hUGDH reaction is continuously regenerated in a three-step chemo-enzymatic cascade. In the first step, reduced NAD+ (NADH) is recycled by xylose reductase from Candida tenuis via reduction of 9,10-phenanthrenequinone (PQ). Radical chemical re-oxidation of this mediator in the second step reduces molecular oxygen to hydrogen peroxide (H2O2) that is cleaved by bovine liver catalase in the last step. A comprehensive analysis of the coupled chemo-enzymatic reactions revealed pronounced inhibition of hUGDH by NADH and UDP-xylose as well as an adequate oxygen supply for PQ re-oxidation as major bottlenecks of effective performance of the overall multi-step reaction system. Net oxidation of UDP-glucose to UDP-xylose by hydrogen peroxide (H2O2) could thus be achieved when using an in situ oxygen supply through periodic external feed of H2O2 during the reaction. Engineering of the interrelated reaction parameters finally enabled production of 19.5 mM (10.5 g L−1) UDP-α-xylose. After two-step chromatographic purification the compound was obtained in high purity (>98%) and good overall yield (46%). The results provide a strong case for application of multi-step redox cascades in the synthesis of nucleotide sugar products. [ABSTRACT FROM AUTHOR]

Hyperbilirubinaemia with or without jaundice is one of the side effects of atazanavir boosted with low-dose ritonavir (ATV/rit) related to the drug plasma levels, as a result of its metabolism by UGT1A1 – uridine diphosphate-glucuronosyl transferase. Genotyping for UGT1A1*28 before initiation of antiretroviral therapy containing atazanavir may aid in identifying individuals at risk of hyperbilirubinaemia. Our objective was to estimate the prevalence of the UGTA1A1*28 polymorphism in HIV-infected individuals in Greece and to determine its potential association with hyperbilirubinaemia in patients receiving ATV/rit. The prevalence of the UGTA1A1*28 variant was estimated in 79 HIV-infected patients prior to the administration of the first-line treatment. The UGTA1A1*28 variant was detected in 46 out of 79 individuals (58.2%). Antiretroviral therapy was administered to 64/79 patients (81%). Among them, 26/64 (40.6%) received ATV/rit. Of the ATV/rit-treated patients, 14 were found to be carriers of the UGT1A1*28 variant (54%), and maximum serum bilirubin levels were significantly higher in the carrier population (4.71 vs. 2.69 mg/dL, p = 0.026). In 50% of the population, maximum levels were recorded in the first month of follow-up. Although carriage of UGT1A1 is linked with the development of hyperbilirubinaemia, the implementation of a pharmacogenomic approach in clinical practice cannot yet be recommended as a standard of care. [ABSTRACT FROM AUTHOR]

The article discusses research on bilirubin as a biomarker and therapeutics for diabetic nephropathy (DN). Topics discussed include noninsulin-dependent diabetes mellitus (NIDDM), the role of heme oxygenase (HO) in bilirubin generation, and uridine diphosphate-glucuronosyl transferase (UDP-GT). Also mentioned are serum bilirubin levels, Irbesartan Diabetic Nephropathy Trial (IDNT), and the Angiotensin II Antagonist Losartan (RENAAL) trial.

O-linked glucosylation of thymine in DNA (base J) is an important regulatory epigenetic mark in trypanosomatids. β-d-glucopyranosyloxymethyluracil (base J) synthesis is initiated by the JBP1/2 enzymes that hydroxylate thymine, forming 5-hydroxymethyluracil (hmU). hmU is then glucosylated by a previously unknown glucosyltransferase. A recent computational screen identified a possible candidate for the base J-associated glucosyltransferase (JGT) in trypanosomatid genomes. We demonstrate that recombinant JGT utilizes uridine diphosphoglucose to transfer glucose to hmU in the context of dsDNA. Mutation of conserved residues typically involved in glucosyltransferase catalysis impairs DNA glucosylation in vitro. The deletion of both alleles of JGT from the genome of Trypanosoma brucei generates a cell line that completely lacks base J. Reintroduction of JGT in the JGT KO restores J synthesis. Ablation of JGT mRNA levels by RNAi leads to the sequential reduction in base J and increased levels of hmU that dissipate rapidly. The analysis of JGT function confirms the two-step J synthesis model and demonstrates that JGT is the only glucosyltransferase enzyme required for the second step of the pathway. Similar to the activity of the related Ten-Eleven Translocation (TET) family of dioxygenases on 5mC, our studies also suggest the ability of the base J-binding protein enzymes to catalyze iterative oxidation of thymine in trypanosome DNA. Here we discuss the regulation of hmU and base J formation in the trypanosome genome by JGT and base J-binding protein. [ABSTRACT FROM AUTHOR]

Purpose: Neutropenia is a life-threatening side effect of irinotecan, and uridine diphosphate glucuronosyltransferases (UGTs) gene polymorphisms are considered to be one of the predictive markers of irinotecan-related toxicities. Many studies have demonstrated that patients bearing UGT1A1*28 have a higher risk of severe neutropenia on toxicity of irinotecan. However, UGT1A1 (TA7/TA7) was very rare in Asian populations. Some researches reported that UGT1A1*28 and/or UGT1A1*6 could predict irinotecan-induced toxicities in Asian populations, but controversial conclusions still remained. This study aims to investigate the association between UGT1A1 gene polymorphisms *6, *6/*28 and irinotecan-related neutropenia in Asian cancer patients receiving irinotecan regimen chemotherapy. Experimental design: Meta-analyses were done to assess the relationship between UGT1A1*6 or UGT1A1*6/*28 and irinotecan-induced neutropenia. Results: The risk of neutropenia was significantly higher among patients with a UGT1A1*6 genotype than among those carrying the UGT1A1*1 allele(s) [odds ratio (OR) 3.276; 95 % confidence interval (CI) 1.887-5.688; P = 0.000 (*6/*6 vs. *1/*6 or *1/*1)], [OR 1.542; 95 % CI 1.180-2.041; P = 0.001 (*6/*6 or *1/*6 vs. *1/*1)]. Also, the risk was significantly higher among patients with a UGT1A1*6/*28 than among those carrying the UGT1A1*1 allele(s) [OR 3.275; 95 % CI 2.152-4.983; P = 0.000 (*6/*6 or *28/*28 or *6/*28 vs. *1/*6 or *1/*28 or *1/*1)]. Conclusions: In conclusion, the UGT1A1*6 and UGT1A1*6/*28 genotypes were associated with an increased risk of irinotecan-induced neutropenia in Asian cancer patients. [ABSTRACT FROM AUTHOR]

Association studies have emerged as a powerful tool for identification of markers associated with quantitative traits in forest trees. The cytosolic enzyme uridine 5′ diphosphate-glucose dehydrogenase (UGDH) converts UDP-glucose to UDP-glucuronate and affects cell wall formation in higher plants. Here, we used association genetics to identify UDP- glucose dehydrogenase ( PtUGDH) allelic variation that associates with wood quality traits in Populus tomentosa. We isolated a 1,828 bp PtUGDH cDNA encoding a polypeptide of 481 amino acids. Expression analysis revealed that PtUGDH was expressed predominantly in young root, developing xylem from vascular tissues, and young leaves, suggesting that UGDH functions in cell wall formation. We identified 59 single-nucleotide polymorphisms (SNPs; π = 0.00475) by resequencing the PtUGDH locus of 40 individuals and genotyped the 22 most common SNPs (minor allele frequency >10 %) in a discovery population ( n = 426). Linkage disequilibrium (LD) analysis showed that LD did not extend over the entire gene ( r < 0.1, within 300 bp). Association studies indicated that three SNPs (false discovery rate, Q < 0.05) and 12 haplotypes ( Q < 0.05) were significantly associated with wood properties. The three significant SNPs are all in the 5′ untranslated regions of PtUGDH, and the phenotypic variance explained by each SNP ranged from 5.37 to 11.97 %. We validated one association in a validation population ( n = 1,200) and validated another association by examining its effect on gene expression. The present study provided molecular markers associated with fiber length and holocellulose content, markers that have potential applications in marker-assisted breeding. [ABSTRACT FROM AUTHOR]