Publications by authors named "Insun Yu"

Expensive fetal bovine serum (FBS) is a major obstacle to the production of cultivated meat. However, because FBS substitutes do not sufficiently induce cell proliferation, a good alternative is to reduce the amount of FBS and use ingestible additives to promote cell proliferation. In this study, Grifola frondosa extract (GFE) was used to investigate its potential as an additive to promote myogenesis of bovine muscle satellite cells from Hanwoo cattle under low serum conditions (10 % FBS).

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The principles of myogenesis play crucial roles in the production of cultured meat, and identifying protein stimulators associated with myogenesis holds great potential to enhance the efficiency of this process. In this study, we used surface plasmon resonance (SPR)-based screening of a natural product library to discover ligands for Pax7 and MyoD, key regulators of satellite cells (SCs), and performed cell-based assays on Hanwoo SCs (HWSCs) to identify substances that promote cell proliferation and/or differentiation. Through an SPR analysis, we found that six chemicals, including one Pax7+/MyoD- chemical, four Pax7+/MyoD+ chemicals, and one Pax7-/MyoD+ chemical, bound to Pax7 and/or MyoD proteins.

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Fetal bovine serum (FBS), which contains various nutrients, comprises 20% of the growth medium for cell-cultivated meat. However, ethical, cost, and scientific issues, necesitates identification of alternatives. In this study, we investigated commercially manufactured serum-free media capable of culturing Hanwoo satellite cells (HWSCs) to identify constituent proliferation enhancing factors.

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Aging is a complex series of multi-organ processes that occur in various organisms. As such, an in vivo study using an animal model of aging is necessary to define its exact mechanisms and identify anti-aging substances. Using as an in vivo model system, we identified extract (CPE) as a novel anti-aging substance.

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In age-related macular degeneration, N-retinylidene-N-retinylethanolamine (A2E) accumulates in retinal pigment epithelium (RPE) cells and generates oxidative stress, which further induces cell death. Polyphenols are well known for their antioxidant and beneficial effects on vision. Chrysanthemum boreale Makino (CB) flowers, which contain flavonoids, have antioxidant activity.

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The electronic effects of nitrogen donors in zinc catalysts for ring-opening polymerization of cyclic esters were investigated. Alkyl and benzyloxy zinc complexes supported by tridentate diamino- and aminoimino phenolate ligands were synthesized, and their solid-state and solution structures characterized. The solution-state structures showed that the alkyl complexes are mononuclear, while the alkoxy complexes are dimeric with the ligands coordinated with different denticities depending on the nature of the ligand donors.

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The synthesis of the first alkoxide-bridged indium complex supported by a chiral dinucleating ligand platform (1), along with its zinc analogue (2), is reported. Both complexes are synthesized in a one-pot reaction starting from a chiral dinucleating bis(diamino)phenolate ligand platform, sodium ethoxide, and respective metal salts. The dinucleating indium analogue (7) based on an achiral ligand backbone is also reported.

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The activity of several group 4 metal alkoxide complexes supported by ferrocene-based ligands was controlled using redox reagents during the ring-opening polymerization of l-lactide and ε-caprolactone. Switching in situ between the oxidized and reduced forms of a metal complex resulted in a change in the corresponding rate of polymerization. Opposite behavior was observed for each monomer used.

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A family of racemic and enantiopure indium complexes 1-11 bearing bulky chiral diaminoaryloxy ligands, H(NNO(R)), were synthesized and fully characterized. Investigation of both the mono- and the bis-alkoxy-bridged complexes [(NNO(R))InX](2)[μ-Y][μ-OEt] (5, R = (t)Bu, X = Y = Cl; 8, R = Me, X = I, Y = OEt) by variable temperature, 2D NOESY, and PGSE NMR spectroscopy confirmed dinuclear structures in solution analogous to those obtained by single-crystal X-ray crystallography. The dinuclear complexes in the family were highly active catalysts for the ring-opening polymerization (ROP) of lactide (LA) to form poly(lactic acid) (PLA) at room temperature.

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An ethoxy-bridged dinuclear indium catalyst was used for the ring opening polymerization of the cyclic ester β-butyrolactone to form the biodegradable polyester poly(hydroxybutyrate) (PHB). The catalyst shows remarkable activity and control during polymerization, allowing for formation of diblock polymers. Addition of high ratios of alcohols to the catalyst leads to fast chain transfer and immortal polymerization.

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Functionalized diaminophenols, H(N(R1R2)N(R3)O), were investigated as ligands for indium catalysts in the ring-opening polymerization of racemic lactide. Precursor complexes (N(Me2)N(Me)O)InCl(2) (1), (N(Pr2)NO)InCl(2) (2), and (N(Mes)NO)InCl(2) (3) were synthesized and fully characterized by (1)H and (13)C NMR spectroscopy, elemental analysis, and single-crystal X-ray crystallography. Complexes 1 and 2 were used to synthesize alkoxy-bridged complexes [(N(Me2)N(Me)O)InCl](2)(μ-Cl)(μ-OEt) (4) and [(N(Pr2)NO)InCl](2)(μ-Cl)(μ-OEt) (5).

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Indium(III) dimethyl, dihalide, and alkoxy-bridged complexes bearing a chiral diaminophenoxy tridentate ligand [NN(H)O](-) were synthesized. The dimethyl complex (NN(H)O)InMe(2) (1) was unreactive toward ethanol and 2-propanol and only partially reactive toward the more acidic phenol. The dihalide complexes (NN(H)O)InX(2) (X = Cl (3), Br (4), I (5)) reacted with NaOEt to form robust alkoxy-bridged complexes with the formula {[(NN(H)O)InX](2)(mu-X)(mu-OEt)} (X = Cl (6), Br (7), I (8)).

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A novel strategy for the synthesis of a substituted polyaniline that can be switched between a self-doped and non-self-doped state is presented. The approach uses the complexation between boronic acid-substituted aniline, a diol (d-fructose), and fluoride to generate an anionic monomer. Under these conditions, chemical polymerization results in a self-doped, water-soluble, conducting polyaniline under neutral aqueous conditions.

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