Joo-hong Park

Mycothiol (MSH) is a small thiol molecule with a cysteine-ligated disaccharide structure found in actinomycetes that include streptomycetes and mycobacteria. In Streptomyces coelicolor, a model organism for antibiotic production and differentiation, the amount of MSH is under the control of a sigma factor sigma(R), which is regulated by an antisigma factor RsrA with a thiol-disulphide redox switch. We found that the first gene (mshA) in the biosynthetic pathway for MSH and the gene for amidase (

Mycothiol is a low molecular weight thiol compound produced by a number of actinomycetes, and has been suggested to serve both anti-oxidative and detoxifying roles. To investigate the metabolism and the role of mycothiol in Streptomyces coelicolor, the biosynthetic genes (mshA, B, C, and D) were predicted based on sequence homology with the mycobacterial genes and confirmed experimentally. Disruption of the mshA, C, and D genes by PCR targeting mutagenesis resulted in no synthesis of mycothiol,

The mammalian gastrointestinal tract accommodates trillions of bacteria, many of which provide beneficial effects to the host, including protection from pathogenic microorganisms and essential metabolites. However, the intestinal immune system needs to adapt to the constantly fluctuating microbial environment at mucosal surfaces in order to maintain homeostasis. In particular, the gut microbiota induces the differentiation of effector Th17 cells and regulatory T cells (Tregs) that express RORγt,

IL-21, a pleiotropic cytokine strongly linked with autoimmunity and inflammation, regulates diverse immune responses. IL-21 can be potently induced in CD4(+) T cells by IL-6; however, very little is known about the mechanisms underlying the transcriptional regulation of the Il21 gene at the chromatin level. In this study, we demonstrated that a conserved noncoding sequence located 49 kb upstream of the Il21 gene contains an enhancer element that can upregulate Il21 gene expression in a STAT3- an

Summary Signal‐specific activation of alternative sigma factors redirects RNA polymerase to induce transcription of distinct sets of genes conferring protection against the damage the signal and the related stresses incur. In Streptomyces coelicolor, σ R (SigR), a member of ECF12 subfamily of Group IV sigma factors, responds to thiol‐perturbing signals such as oxidants and electrophiles, as well as to translation‐blocking antibiotics. Oxidants and electrophiles interact with and inactivate the z

After conducting comparative research into the process of forming the Theory of Constitution in Ancient Western Medicine and that of Four Trigrams Constitution(Sasang Constitution, 四象體質) in Korean Medicine and contents of two Theories of Constitution in terms of medical history, both theories were found to be formed by an interaction between philosophy and medicine, followed by a combination of the two, on a philosophical basis. The Theory of Constitution in Ancient Western Medicine began with t

After conducting comparative research into the process of forming the Theory of Constitution in Ancient Western Medicine and that of Four Trigrams Constitution(Sasang Constitution) in Korean Medicine and contents of two Theories of Constitution in terms of medical history, both theories were found to be formed by an interaction between philosophy and medicine, followed by a combination of the two, on a philosophical basis. The Theory of Constitution in Ancient Western Medicine began with the The

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In this study, we analyzed the innovation pattern of product and process between Korean, Japanese and German chemical firms. To do this study, a mail survey was chosen as the data collection method. For the empirical study, 36 Korean, 35 Japanese and 50 German chemical firms were analyzed. The major results are indicated as follows: (1) The Korean and Japanese firms have focused more on the process innovation, while the German firm have focused more on the product innovation. (2) The Korean and

This paper proposes the application of a sliding mode controller (SMC), known for its robustness to nonlinearity, uncertainty, and external disturbances, to an axial magnetic bearing system that requires continuous support under high axial loads. Force and current coefficients are derived from magnetic circuit analysis and incorporated into the control parameters. The control input is designed based on Lyapunov stability theory. In addition, a full-state observer is developed to estimate the rot