Eun-Suk Son

Taxonomy of Ganoderma lucidum from Korea Based on rDNA and Partial β-Tubulin Gene Sequence Analysis

In the present study, a phylogenetic analysis was undertaken based on the internal transcribed spacer (ITS) rDNA and partial β -tubulin gene sequence of the Ganoderma species. The size of the ITS rDNA regions from different Ganoderma species varied from 625 to 673 bp, and those of the partial β-tubulin gene sequence were 419 bp. Based on the results, a phylogenetic tree was prepared which revealed that Korean Ganoderma lucidum strains belong in a single group along with a G. lucidum strain from Bangladesh.

Effects of Ganodermanondiol, a New Melanogenesis Inhibitor from the Medicinal Mushroom Ganoderma lucidum

Ganoderma lucidum, a species of the Basidiomycetes class, has been attracting international attention owing to its wide variety of biological activities and great potential as an ingredient in skin care cosmetics including “skin-whitening” products. However, there is little information available on its inhibitory effect against tyrosinase activity. Therefore, the objectives of this study were to investigate the chemical composition of G. lucidum and its inhibitory effects on melanogenesis. We isolated the active compound from G. lucidum using ethanol extraction and ethyl acetate fractionation. In addition, we assayed its inhibitory effects on tyrosinase activity and melanin biosynthesis in B16F10 melanoma cells. In this study, we identified a bioactive compound, ganodermanondiol, which inhibits the activity and expression of cellular tyrosinase and the expression of tyrosinase-related protein-1 (TRP-1), TRP-2, and microphthalmia-associated transcription factor (MITF), thereby decreasing melanin production. Furthermore, ganodermanondiol also affected the mitogen-activated protein kinase (MAPK) cascade and cyclic adenosine monophosphate (cAMP)-dependent signaling pathway, which are involved in the melanogenesis of B16F10 melanoma cells. The finding that ganodermanondiol from G. lucidum exerts an inhibitory effect on tyrosinase will contribute to the use of this mushroom in the preparation of skin care products in the future.

Next-generation sequencing-based genome-wide mutation analysis of l-lysine-producing Corynebacterium glutamicum ATCC 21300 strain

In order to identify single nucleotide polymorphism and insertion/deletion mutations, we performed whole-genome re-sequencing of the enhanced l-lysine-producing Corynebacteriumglutamicum ATCC 21300 strain. In total, 142 single nucleotide polymorphisms and 477 insertion/deletion mutations were identified in the ATCC 21300 strain when compared to 3,434 predicted genes of the wild-type C. glutamicum ATCC 13032 strain. Among them, 110 transitions and 29 transversions of single nucleotide polymorphisms were found from genes of the ATCC 21300 strain. In addition, 11 genes, involved in the L-lysine biosynthetic pathway and central carbohydrate metabolism, contained mutations including single nucleotide polymorphisms and insertions/deletions. Interestingly, RT-PCR analysis of these 11 genes indicated that they were normally expressed in the ATCC 21300 strain. This information of genome-wide gene-associated variations will be useful for genome breeding of C. glutamicum in order to develop an industrial amino acid-producing strain with minimal mutation.

Apple pomace increases mycelial growth of Pleurotus ostreatus

Apple pomace is a by-product from the apple processing industry and has the potential to support the growth of microorganisms. In this study, the effect of apple pomace on the growth rate of Pleurotus ostreatus mycelium was investigated. The mycelial growth dramatically increased by 34.5, 20 and 26% in solid culture, liquid culture, and solid-state fermentation, respectively, by adding 2.5% apple pomace. However, the growth of P. ostreatus mycelia was slightly inhibited by adding 5 or 10% compared to 2.5% apple pomace. Our findings reveal that apple pomace utilization can become a model for the valuable addition of similar wastes, and for the development of a solid-state fermenter.

Effect of cultured medium of human umbilical cord blood-derived mesenchymal stem cells on melanogenic enzyme activity in mouse B16 melanoma cells

The cultured medium of mesenchymal stem cell is a valuable resource for a variety of stem cell-derived cytokines and growth factors with a potential therapeutic effect on skin diseases. Here, we investigated the effect of the cultured medium of human umbilical cord blood-derived mesenchymal stem cell (CM-hCBSC) on melanogenesis in mouse B16 melanoma cells stimulated by α-melanocyte stimulating hormone (α-MSH). Our results show that CM-hCBSC inhibits melanin synthesis due to the decrease in cellular tyrosinase activity in B16 melanoma cells without cytotoxicity. The activity of melanogenic enzymes such as tyrosinase, tyrosinase-related protein-1 (TRP-1), and TRP-2 were evaluated by western blot and semi-quantitative RT-PCR. The CM-hCBSC down-regulated the protein and mRNA expression levels of tyrosinase and TRP-1 in a dose-dependent manner. In addition, TRP-2 protein and mRNA expression levels were found to be down-regulated to a lesser extent. We also measured the level of cytokines in CM-hCBSC using the Luminex total system. It was found that the top enriched cytokine in the CMhCBSC was interukine-6 (IL-6), known as a potent regulator of melanin synthesis together with IL-1α and tumor necrosis factor α (TNF- α). These results indicate that secretary factors including IL-6 in the CM-hCBSC may inhibit melanin synthesis by down-regulating the expression of tyrosinase and TRP1. This study suggests that CMhCBSC has a therapeutic effect as an anti-melanogenic agent and may be effective against hyperpigmentation disorders.