Seong-Won Song

Bio: Seong-Won Song is an academic researcher. The author has contributed to research in topics: Esterase & Immobilized enzyme. The author has an hindex of 2, co-authored 3 publications receiving 18 citations.

Enantioselective production of levofloxacin by immobilized porcine liver esterase

Abstract: Porcine liver esterase, which cleaves ofloxacin butyl ester enantioselectively to levofloxacin, was successfully immobilized in calcium alginate and polyacrylamide gel. Immobilized esterase in 5% (w/v) calcium alginate exhibited 58% immobilization efficiency and could be reused five times without severe loss of enzyme activity. On the other hand, entrapped esterase in polyacrylamide gel, composed of 20% of total monomer and 8.3% of cross-linking agent, could be reused 10 times, and 51% of enzyme activity remained after the 10th batch without decrease of enantioselectivity. Compared with entrapped methods, significant reduction of enzyme activity was found in the case of physical adsorption on to QAE-Sephadex.

Polyacrylamide Gel Immobilization of Porcine Liver Esterase for the Enantioselective Production of Levofloxacin

Abstract: Porcine liver esterase was immobilized in polyacrylamide gel for the enantioselective production of levofloxacin from ofloxacin butyl ester. The initial activity of immobilized esterase was found to be significantly affected by the polyacrylamide gel composition. The optimum concentrations of monomer and crosslinker were determined to be 20% and 8.3%, respectively. The activity of immobilized esterase was 55.4% compared to a free enzyme. Enantiomeric excess was maintained at 60%, almost the same level as that of free enzyme. In addition, the immobilized esterase could be used repeatedly up to 10 times without experiencing any severe loss of activity and enantioselectivity.

Comparison between of the attenuated BR-Oka and the wild type strain of Varicella Zoster Virus (VZV) on the DNA level.

Abstract: Oka strain VR-795 (Varicella Zoster Virus, VZV) of American Type Culture Collection (ATCC) has been used for chickenpox vaccine production. In order to use this strain for vaccine production, the strain must be identified and its stability must be confirmed. The identification of the Oka strain has been confirmed using Restriction Fragment Length Polymorphism (RFLP) and DNA sequence analysis of glycoprotein-II (gp-II). The amino acid sequences of Oka deduced from the DNA sequence of gp-II have changed at three amino acids against Ellen and at one amino acid against Webster. To prove the stability of the Oka strain during the passage, RFLP and DNA sequence analyses were also used with 11, 15 and 23 times of virus passage. We found that the Oka strain was stable at passages of up to 23 times, based on the RFLP and DNA sequence analyses. The confirmed Oka strain was renamed as BR-Oka for the purposes of chickenpox vaccine production.

Production and applications of esterases

Abstract: Esterase plays a major role in the degradation of natural materials and industrial pollutants, viz, cereal wastes, plastics, and other toxic chemicals It is useful in the synthesis of optically pure compounds, perfumes, and antioxidants The potential applications of esterase with reference to agriculture, food, and pharmaceutical industries, are discussed in this review Promising applications in this avenue can be supported by appropriate production strategies

Microarray Analysis of Host Cell Gene Transcription in Response to Varicella-Zoster Virus Infection of Human T Cells and Fibroblasts In Vitro and SCIDhu Skin Xenografts In Vivo

Abstract: During primary infection, varicella-zoster virus (VZV) is spread via lymphocytes to skin, where it induces a rash and establishes latency in sensory ganglia. A live, attenuated varicella vaccine (vOka) was generated by using the VZV Oka strain (pOka), but the molecular basis for vOka attenuation remains unknown. Little is known concerning the effects of wild-type or attenuated VZV on cellular gene regulation in the host cells that are critical for pathogenesis. In this study, transcriptional profiles of primary human T cells and fibroblasts infected with VZV in cell culture were determined by using 40,000-spot human cDNA microarrays. Cellular gene transcription in human skin xenografts in SCID mice that were infected with VZV in vivo was also evaluated. The profiles of cellular gene transcripts that were induced or inhibited in infected human foreskin fibroblasts (HFFs), T cells, and skin in response to pOka and vOka infection were similar. However, significant alterations in cellular gene regulation were observed among the three differentiated human cell types that were examined, suggesting specific differences in the biological consequences of VZV infection related to the target cell. Changes in cellular gene transcription detected by microarray analysis were confirmed for selected genes by quantitative real-time reverse transcription-PCR analysis of VZV-infected cells. Interestingly, the transcription of caspase 8 was found to be decreased in infected T cells but not in HFFs or skin, which may signify a tissue-specific antiapoptosis mechanism. The use of microarrays to demonstrate differences in effects on host cell genes in primary, biologically relevant cell types provides background information for experiments to link these various response phenotypes with mechanisms of VZV pathogenesis that are important for the natural course of human infection.

Varicella-Zoster Virus

Abstract: Varicella-zoster virus (VZV) is one of the eight herpesviruseso that infects humans The virus causes two diseases, varicella (chickenpox) and zoster (shingles) (1) Varicella is primarily an illness of children, although as many as 5% of adults in the United States may be susceptible Zoster is caused by reactivation of latent VZV infection in sensory ganglia, which resulted during the attack of varicella, usually years to decades previously VZV is able to cause a persistent infection in sensory ganglia without harm, expressing only 5 of its 70 gene products (2) In the setting of a low cell-mediated immune response to VZV, however, full gene expression can occur, and infectious virus may be formed within ganglia and transferred down the axon to the skin (1) Zoster occurs in about 15% of people over their lifetime It characteristically occurs despite the presence of high titers of antibodies to VZV Little more is understood about reactivation of VZV; it occurs most commonly in elderly and immunocompromised populations Reasons for its development in otherwise healthy young persons are not fully understood, but fortunately it is a rather uncommon occurrence