Distributed Electronic Commerce cluster for small enterprise

The Electronic Commerce System should provide prompt responses for user requests and continuous services despite partial failures of its sub systems. In addition, scalability and flexibility should be supported as the number of customers increases. Because Electronic Commerce is beyond the national border, the system should be implemented across different subnets for its efficiency and business needs. This paper proposes the design and implementation of a distributed system infrastructure across different subnets for Electronic Commerce. When the Electronic Commerce system is owned and managed by a small enterprise, the cost should be considered as well as fault tolerance, high availability and scalability. The proposed infrastructure was evaluated and discussed in the aspect of economics such as implementation and management cost, performance and overhead.     

Mycorrhizal symbioses found in roots of fern and its relatives in Korea

Mycorrhizal symbioses were found in the roots of 45 out of 59 species of pteridophytes collected in Korea. The mycorrhizal fungi were colonized in the root cortical cells, primarily in terrestrial species, but rarely in epiphytic or aquatic pteridophytes. Mycorrhizae that are typically found in orchid colonized the roots of the epiphytic pteridophytes, but not in other species. These were the first observations of orchid mycorrhizae in pteridophytes. Arbuscular mycorrhizal fungi were examined after staining, then confirmed with PCR, using a specific primer. This is the first report of arbuscular mycorrhizal colonization in the roots of pteridophyte species in Asia.     

Crystal structure of <Emphasis Type="Italic">Rattus norvegicus</Emphasis> Visfatin/PBEF/Nampt in complex with an FK866-based inhibitor

Visfatin (Nampt/PBEF) plays a pivotal role in the salvage pathway for NAD⁺ biosynthesis. Its potent inhibitor, FK866, causes cellular NAD⁺ levels to decline, thereby inducing apoptosis in tumor cells. In an effort to improve the solubility and binding interactions of FK866, we designed and synthesized IS001, in which a ribose group is attached to the FK866 pyridyl ring. Here, we report the crystal structure of rat visfatin in complex with IS001. Like FK866, IS001 is positioned at the dimer interface, and all of the residues that interact with IS001 are involved in hydrophobic or π-π-stacking interactions. However, we were unable to detect any strong interactions between the added ribose ring of IS001 and visfatin, which implies that a bulkier modifying group is necessary for a tight interaction. This study provides additional structure-based information needed to optimize the design of visfatin inhibitors. These authors contributed equally to this work.     

Lipase-catalyzed hydrolysis of fish oil in an optimum emulsion system

In this study, fish oil was hydrolyzed by lipase in a fish oil-in-water emulsion system in an effort to improve the functional properties of fish oil. Lipase activity was found to depend on the quality of the water/fish oil interface area. We selected several suitable emulsifiers, and their emulsifying activities were evaluated under a variety of conditions, including concentration, water-oil ratios, pH values, and temperature. Among the selected emulsifiers, the emulsifying activity of gelatin was higher than those of carboxymethyl chitin (CM-chitin), bovine serum albumin, and Tween-20, all of which are commercial emulsificers Moreover, the emulsifying activity of the gelatin solution was the highest at 0.5%, and was reduced with increasing concentrations of above 1%. The optimal water-oil ratio, pH, and temperature conditions were 40% (w/v), pH 8.0 and 40°C, respectively. Under these conditions, the emulsifying activity of gelatin solution was 86%. The emulsion structure of the gelatin solution was characterized by high density and small particle size. The degree of sardine oil hydrolysis in the emulsion system was 50% higher than that of the non-emulsion system. The lipid species of the lipase-prepared sardine oil hydrolysates were identified as triacylglycerol, 1,3- and 1,2-diacylglycerol, monoacylglycerol, and fatty acid.     

Efficient Itaconic acid production via protein–protein scaffold introduction between GltA,AcnA, and CadA in recombinant Escherichia coli

Itaconic acid, which is a promising organic acid in synthetic polymers and some base-material production, has been produced by Aspergillus terreus fermentation at a high cost. The recombinant Escherichia coli that contained the cadA gene from A. terreus can produce itaconic acid but with low yield. By introducing the protein–protein scaffold between citrate synthesis, aconitase, and cis-aconitase decarboxylase, 5.7 g/L of itaconic acid was produced, which is 3.8-fold higher than that obtained with the strain without scaffold. The optimum pH and temperature for itaconic acid production were 8.5 and 30°C, respectively. When the competing metabolic network was inactivated by knock-out mutation, the itaconic acid concentration further increased, to 6.57 g/L.