Publications by authors named "Joon-Hyung Ahn"

Genome-wide association study (GWAS) is effective in identifying favorable alleles for traits of interest with high mapping resolution in crop species. In this study, we conducted GWAS to explore quantitative trait loci (QTL) for eight fruit traits using 162 tomato accessions with diverse genetic backgrounds. The eight traits included fruit weight, fruit width, fruit height, fruit shape index, pericarp thickness, locule number, fruit firmness, and brix.

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A new vehicle is designed for the intracellular delivery of antibodies at nanomolar concentrations by combination of domain Z, a small affibody with strong binding affinity to Fc regions of immunoglobulin G (IgG), and the multimers of LK sequences, α-helical cell penetrating peptides (CPP) with powerful cell penetrating activities. Domain Z and multimeric LK are fused together to form LK-domain Z proteins. The LK-domain Z can bind with IgG at a specific ratio at nanomolar concentrations by simple mixing.

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Article Synopsis
  • Developed a pH-activatable cell-penetrating peptide dimer, LH, with histidine residues that penetrates cells under weak acidic conditions at low concentrations.
  • LH effectively delivers the chemotherapy drug paclitaxel (PTX) into triple-negative breast cancer cells through both non-covalent and covalent bonding.
  • In mouse models, both delivery methods demonstrated strong anti-tumor effects against triple-negative breast cancer at very low doses, with LH showing prolonged circulation and enhanced tumor accumulation.
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In this study, we propose a reversible covalent conjugation method for peptides, proteins, and even live cells based on specific recognition between natural amino acid sequences. Two heptad sequences can specifically recognize each other and induce the formation of a disulfide bond between cysteine residues. We show the covalent bond formation and dissociation between peptides and proteins in cell-free conditions and on the surface of live cells.

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The intracellular delivery of transcription factor/cofactor using cell penetrating peptide (CPP) can lead to selective osteogenesis. The present work investigates the cell-penetrating potential of the a cyclic, α-helical cell-penetrating peptide based on leucine and lysine residues (cLK) for intracellular delivery in MC3T3 cells and the osteogenic effects of a C-terminal proline‑serine‑threonine-rich (PST) domain of Runx2 using cLK in rat mesenchymal stem cells (MSCs). We confirmed that the combination of cLK and fluorescein 5-isothiocyanate (FITC)-fragmented-Runx2 (fRunx2) showed an enhanced cell-penetrating activity of FITC-fRunx2 compared with FITC-fRunx2 alone.

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We stapled an amphipathic peptide mainly consisting of leucine (L) and lysine (K) by an azobenzene (Ab) linker for photocontrol of the secondary structure. The cis- trans isomerization of the Ab moieties could stabilize and destabilize the α-helical conformation of the LK peptide along with dramatic change of associated peptide structures in a reversible manner by UV-vis irradiation. The cell-penetrating activities of the LK peptide can be readily regulated by the photocontrol, as the stabilized cis-Ab-LK peptide showed remarkable increase of cell penetration compared to the destabilized trans-Ab-LK peptide.

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Plant growth promoting rhizobacteria Ochrobactrum lupini KUDC1013 and Novosphingobium pentaromativorans KUDC1065 isolated from Dokdo Island, S. Korea are capable of eliciting induced systemic resistance (ISR) in pepper against bacterial spot disease. The present study aimed to determine whether plant growth-promoting rhizobacteria (PGPR) strains including strain KUDC1013, strain KUDC1065, and Paenibacillus polymyxa E681 either singly or in combinations were evaluated to have the capacity for potential biological control and plant growth promotion effect in the field trials.

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