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Glycosyltransferase Gene (glycosyltransferase + gene)

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Life Sciences50%

Selected Abstracts

The exopolysaccharide of Rhizobium sp.

ENVIRONMENTAL MICROBIOLOGY, Issue 8 2008
Brassica napus roots but contributes to root colonization, YAS34 is not necessary for biofilm formation on Arabidopsis thaliana
Summary Microbial exopolysaccharides (EPSs) play key roles in plant,microbe interactions, such as biofilm formation on plant roots and legume nodulation by rhizobia. Here, we focused on the function of an EPS produced by Rhizobium sp. YAS34 in the colonization and biofilm formation on non-legume plant roots (Arabidopsis thaliana and Brassica napus). Using random transposon mutagenesis, we isolated an EPS-deficient mutant of strain YAS34 impaired in a glycosyltransferase gene (gta). Wild type and mutant strains were tagged with a plasmid-born GFP and, for the first time, the EPS produced by the wild-type strain was seen in the rhizosphere using selective carbohydrate probing with a fluorescent lectin and confocal laser-scanning microscopy. We show for the fist time that Rhizobium forms biofilms on roots of non-legumes, independently of the EPS synthesis. When produced by strain YAS34 wild type, EPS is targeted at specific parts of the plant root system. Nutrient fluctuations, root exudates and bacterial growth phase can account for such a production pattern. The EPS synthesis in Rhizobium sp. YAS34 is not essential for biofilm formation on roots, but is critical to colonization of the basal part of the root system and increasing the stability of root-adhering soil. Thus, in Rhizobium sp. YAS34 and non-legume interactions, microbial EPS is implicated in root,soil interface, root colonization, but not in biofilm formation. [source]

Role of UGT1A1 mutation in fasting hyperbilirubinemia

JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 6 2001
Tomoaki Ishihara
Abstract Background and Aim: Low-grade fasting hyperbilirubinemia is a common observation in healthy subjects (HS), whereas high-grade fasting hyperbilirubinemia is believed to be a characteristic finding of Gilbert's syndrome. This study was undertaken to assess the role of mutation in bilirubin UDP- glycosyltransferase gene (UGT1A1) on fasting hyperbilirubinemia. Methods: Analysis of UGT1A1 and a caloric restriction test (400 kcal for 24 h) were performed in 56 healthy subjects (25 males, 31 females), and 28 patients with Gilbert's syndrome (18 males, 10 females). There were 29 healthy subjects with no mutation in UGT1A1, and 27 healthy subjects and 26 Gilbert's syndrome patients with mutations in the coding and/or promoter (TATA box) regions of UGT1A1. Results: The mean increment of serum bilirubin (,SB) was 9.6 ,mol/L (males) and 4.1 ,mol/L (females) in subjects with no UGT1A1 mutation. Subjects with mutation in UGT1A1 showed higher levels of ,SB than individuals without mutation. Among healthy subjects, gender difference in ,SB values was observed only in individuals with the wild type of UGT1A1, but not in those with mutations in this gene. Conclusion: The results of the present study suggest that UGT1A1 mutation has a role in the development of high-grade fasting hyperbilirubinemia after caloric restriction. [source]

Genetic engineering approach for the production of rhamnosyl and allosyl flavonoids from Escherichia coli

BIOTECHNOLOGY & BIOENGINEERING, Issue 1 2010
Dinesh Simkhada
Abstract The main functions of glycosylation are stabilization, detoxification and solubilization of substrates and products. To produce glycosylated products, Escherichia coli was engineered by overexpression of TDP- L -rhamnose and TDP-6-deoxy- D -allose biosynthetic gene clusters, and flavonoids were glycosylated by the overexpression of the glycosyltransferase gene from Arabidopsis thaliana. For the glycosylation, these flavonoids (quercetin and kaempferol) were exogenously fed to the host in a biotransformation system. The products were isolated, analyzed and confirmed by HPLC, LC/MS, and ESI-MS/MS analyses. Several conditions (arabinose, IPTG concentration, OD600, substrate concentration, incubation time) were optimized to increase the production level. We successfully isolated approximately 24,mg/L 3- O -rhamnosyl quercetin and 12.9,mg/L 3- O -rhamnosyl kaempferol upon feeding of 0.2,mM of the respective flavonoids and were also able to isolate 3- O -allosyl quercetin. Thus, this study reveals a method that might be useful for the biosynthesis of rhamnosyl and allosyl flavonoids and for the glycosylation of related compounds. Biotechnol. Bioeng. 2010;107: 154,162. © 2010 Wiley Periodicals, Inc. [source]

Cloning and Sequencing of the Biosynthetic Gene Cluster for Saquayamycin Z and Galtamycin B and the Elucidation of the Assembly of Their Saccharide Chains

CHEMBIOCHEM, Issue 8 2009
Annette Erb
Abstract Sweet ways: We have investigated the glycosyltransferase genes of the saquayamycin Z (shown) and galtamycin B biosynthetic gene cluster from Micromonospora sp. Tü6368. The results unambiguously show that both compounds are derived from the same cluster. Furthermore, the function of five glycosyltransferases was elucidated, and the results have shed light on the assembly of the sugar chains. The Gram-positive bacterium, Micromonospora sp. Tü6368 produces the angucyclic antibiotic saquayamycin Z and the tetracenequinone galtamycin B. The structural similarity of both compounds suggests a common biosynthetic pathway. The entire biosynthetic gene cluster (saq gene cluster) was cloned and characterized. DNA sequence analysis of a 36.7 kb region revealed the presence of 31 genes that are probably involved in saquayamycin Z and galtamycin B formation. Heterologous expression experiments and targeted gene inactivations were carried out to specifically manipulate the saquayamycin Z and galtamycin B pathways; this demonstrated unambiguously that both compounds are derived from the same cluster. The inactivation of glycosyltransferase genes led to the production of novel saquayamycin and galtamycin derivatives, provided information on the assembly of the sugar chains, and showed that tetracenequinones are formed from angucyclines. [source]