15 research outputs found
Erlang-based Software Update Platform for Mobile Devices
Growing computational power of mobile devices modifies existing approachesto data processing in large-scale sensor networks. Since sensors are no lon-ger limited to simple data acquisition tasks, such networks can be consideredcomplex geo-distributed data processing systems. Features and requirements ofsuch systems justify use of Erlang language and technology for programmingmobile devices. The technology provides several crucial features, including fault-tolerance, message-passing concurrency or hot-code loading. In this paper theproblem of software management in Erlang-based distributed systems is di-scussed. A mechanism for installing and upgrading Erlang applications usingoperating system package manager is described. A platform for updating so-ftware in large scale systems is presented
Large-Scale Synthesis of Globotriose Derivatives Through Recombinant E. coli.
The carbohydrate chains decorating cell membranes and secreted proteins participate in a range of important biological processes. However, their ultimate significance and possible therapeutic potential have not been fully explored due to the lack of economical methods for their production. This study is an example of the use of a genetically engineered bacterial strain in the preparation of diverse oligosaccharides. Based on an ex vivo biosynthetic pathway, an artificial gene cluster was constructed by linking the genes of five associated enzymes on a plasmid vector. This plasmid was inserted into the E. coli NM522 strain to form globotriose-producing cells ('superbug' pLDR20-CKTUF). The specific strain was conveniently applied to the synthesis of globotriose trisaccharide and its derivatives, as potential neutralizers for Shiga toxin. This work demonstrates a novel and economical method for generating ligand diversity for carbohydrate drug development
Correction to: Passive blood anaphylaxis: subcutaneous immunoglobulins are a cause of ongoing passive anaphylactic reaction
Upon publication of the original article [1], the authors reported the following funding information was omitted: Publication supported by Wroclaw Centre of Biotechnology, programme The Leading National Research Centre (KNOW) for years 2014–2018
Donor Substrate Regeneration for Efficient Synthesis of Globotetraose and Isoglobotetraose
Here we describe the efficient synthesis of two oligosaccharide moieties of human glycosphingolipids, globotetraose (GalNAcβ1→3Galα1→4Galβ1→4Glc) and isoglobotetraose (GalNAcβ1→3Galα1→3Galβ1→4Glc), with in situ enzymatic regeneration of UDP-N-acetylgalactosamine (UDP-GalNAc). We demonstrate that the recombinant β-1,3-N-acetylgalactosaminyltransferase from Haemophilus influenzae strain Rd can transfer N-acetylgalactosamine to a wide range of acceptor substrates with a terminal galactose residue. The donor substrate UDP-GalNAc can be regenerated by a six-enzyme reaction cycle consisting of phosphoglucosamine mutase, UDP-N-acetylglucosamine pyrophosphorylase, phosphate acetyltransferase, pyruvate kinase, and inorganic pyrophosphatase from Escherichia coli, as well as UDP-N-acetylglucosamine C4 epimerase from Plesiomonas shigelloides. All these enzymes were overexpressed in E. coli with six-histidine tags and were purified by one-step nickel-nitrilotriacetic acid affinity chromatography. Multiple-enzyme synthesis of globotetraose or isoglobotetraose with the purified enzymes was achieved with relatively high yields
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Cloning, expression and characterization of a UDP-galactose 4-epimerase from Escherichia coli
The gene galE encoding UDP-galactose 4-epimerase was cloned into E. coli BL21(DE3) from the chromosomal DNA of E. coli strain K-12. High expression of the soluble recombinant epimerase was achieved in the cell lysate. In order to evaluate the use of this epimerase in enzymatic synthesis of important α-Gal epitopes (oligosaccharides with a terminal Galα1,3Gal sequence), a new radioactivity assay (α1,3-galactosyltransferase coupled assay) was established to characterize its activity in producing UDP-galactose from UDP-glucose. Approximately 2700 units (100 mg) enzyme with a specific activity of 27 U mg−1 protein could be obtained from one liter of bacterial culture. The epimerase was active in a wide pH range with an optimum at pH 7.0. This expression system established a viable route to the enzymatic production of α-Gal oligosaccharides to support xenotransplantation research
Evaluation of Partial Nitritation/Anammox (PN/A) Process Performance and Microorganisms Community Composition under Different C/N Ratio
A one-stage partial nitritation/anammox (PN/A) process with intermittent aeration is possible under sidestream conditions, but implementation in a mainstream is a challenge due to increased Carbon/Nitrogen (C/N) ratios in domestic wastewater. This study investigated the effect of C/N ratios on process efficiency and the effect of narrowing non-aeration time on process improvement at high chemical oxygen demand (COD) load. An increase in TN removal efficiency was achieved in both series with gradual change of C/N ratio from 1 to 3, from 65.1% to 83.4% and 63.5% to 78% in 1st and 2nd series, respectively. However, at the same time, the ammonium utilization rate (AUR) value decreased with the increase in C/N ratio. At a high COD (C/N = 3) concentration, the process broke down and regained productivity after narrowing the non-aeration time in both series. Shifts in the system performance were also connected to adaptive changes in microbial community revealed by data obtained from 16S rRNA NGS (next-generation sequencing), which showed intensive growth of the bacteria with dominant heterotrophic metabolism and the decreasing ratio of autotrophic bacteria. The study shows that deammonification is applicable to the mainstream provided that the C/N ratio and the aeration/non-aeration time are optimized
Correction to: Passive blood anaphylaxis: subcutaneous immunoglobulins are a cause of ongoing passive anaphylactic reaction
Evaluation of Partial Nitritation/Anammox (PN/A) Process Performance and Microorganisms Community Composition under Different C/N Ratio
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Reassembled Biosynthetic Pathway for Large-Scale Carbohydrate Synthesis: α-Gal Epitope Producing "Superbug"
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Synthesis of Galactose-Containing Oligosaccharides through Superbeads and Superbug Approaches: Substrate Recognition along Different Biosynthetic Pathways
Galactosides as carbohydrate receptors play critical roles in biological recognition events. α-galactosyl (α-gal) epitopes and globotriose are two representative galactosyloligosaccharides with therapeutic significance. Neutralization of anti-gal with free α-gal and its derivatives is a promising treatment to overcome hyper-acute rejection (HAR). It is clear that further studies on preventing HAR and protecting humans from pathogen attack require easy access to substantial amounts of α-gal and globotriose, as well as their analogs. The superbeads and superbug are versatile tools that have shown utility in synthesis of galactoside analogs. At present, other sugar–nucleotide regeneration systems are being constructed to synthesize diverse glycoconjugates and unnatural derivatives. The success of superbeads and the superbug technology offers the promise of easily synthesizing diversified oligosaccharides and glycoconjugates with uncommon or even unnatural sugar residues to meet increasing biochemical demands. On the other hand, the substrate recognition between substrates and enzymes has a dual function. With the superbeads and superbug approaches, it holds promise for the screening of possible inhibitors in the biosynthetic pathway, if the substrates cannot be adopted as suitable donor or acceptors