Soon-Yong Choi

Antimicrobial and Anti-Inflammatory Effects of Cecropin A(1-8)–Magainin2(1-12) Hybrid Peptide Analog P5 against Malassezia furfur Infection in Human Keratinocytes

The lipophilic fungus Malassezia furfur (M. furfur) is a commensal microbe associated with several chronic diseases such as pityriasis versicolor, folliculitis, and seborrheic dermatitis. Because M. furfur-related diseases are difficult to treat and require prolonged use of medications, the treatment for M. furfur-related skin diseases is supposed to gain control over M. furfur growth and the inflammation associated with it, as well as to prevent secondary infections. In this study, we investigated the antifungal and anti-inflammatory effects of cecropin A(1-8)-magainin 2(1-12) hybrid peptide analog P5 on M. furfur. The minimal inhibitory concentration of P5 against M. furfur was 0.39 μM, making it 3-4 times more potent than commonly used antifungal agents such as ketoconazole (1.5 μM) or itraconazole (1.14 μM). P5 efficiently inhibited the expression of IL-8 and Toll-like receptor 2 in M. furfur-infected human keratinocytes without eukaryotic cytotoxicity at its fungicidal concentration. Moreover, P5 significantly downregulated NF-κB activation and intracellular calcium fluctuation, which are closely related with enhanced responses of keratinocyte inflammation induced by M. furfur infection. Taken together, these observations suggest P5 may be a potential therapeutic agent for M. furfur-associated human skin diseases because of its distinct antifungal and anti-inflammatory action.

Molecular cloning and expression of the hot pepper ERabp1 gene encoding auxin-binding protein

The 22 kDa auxin-binding proteins in higher plants have received considerable attention as candidates for an auxin receptor. A cDNA clone Ca-ERabp1 of hot pepper (Capsicum annum) was isolated using the oligonucleotides as PCR primers. The cDNA codes for a polypeptide related to the major 22 kDa auxin-binding protein from maize and Arabidopsis ERabp1. The deduced amino acid sequence contains an endoplasmic reticulum retention signal, the KDEL sequence located at the C-terminal end, and has two possible auxin-binding sites, HRHSCE and YDDWSVPHTA conserved sequences. Northern hybridization analysis revealed that the Ca-ERabp1 gene is differentially expressed in total RNA isolated from different organs of a pepper plant, showing the highest level of expression in fruits but barely detectable in leaves and roots.

The conformation and CETP inhibitory activity of [10]-dehydrogingerdione isolated from Zingiber officinale

In the course of searching for cholesteryl ester transfer protein (CETP) inhibitors from natural sources, a new type of CETP inhibitor, [10]-dehydrogingerdione (1), was isolated from the extract of rhizomes of Zingiber officinale Roscoe. By NMR spectroscopic analysis of its 1HNMR, 13C-NMR, and 1H-1H COSY, HMBC, HMQC and NOESY, more precise structure, compared with its originally proposed structures, of [10]-dehydrogingerdione has been elucidated. This active compound inhibited human plasma CETP with IC50 values of 35 μM.

Insect ornithine decarboxylase (ODC) complements SPE1 knock-out of yeast Saccharomyces cerevisiae

Ornithine decarboxylase (ODC) is a rate-limiting enzyme in the biosynthesis of polyamines, which are essential for cell growth, differentiation, and proliferation. This report presents the characterization of an ODC-encoding cDNA (SlitODC) isolated from a moth species, the tobacco cutworm, Spodoptera litura (Lepidoptera); its expression in a polyamine-deficient strain of yeast, S. cerevisiae; and the recovery in polyamine levels and proliferation rate with the introduction of the insect enzyme. SlitODC encodes 448 amino acid residues, 4 amino acids longer than B. Mori ODC that has 71% identity, and has a longer C-terminus, consistent with B. mori ODC, than the reported dipteran enzymes. The null mutant yeast strain in the ODC gene, SPE1, showed remarkably depleted polyamine levels; in putrescine, spermidine, and spermine, the levels were > 7, > 1, and > 4%, respectively, of the levels in the wild-type strain. This consequently caused a significant arrest in cell proliferation of > 4% of the wild-type strain in polyaminefree media. The transformed strain, with the substituted SlitODC for the deleted endogenous ODC, grew and proliferated rapidly at even a higher rate than the wild-type strain. Furthermore, its polyamine content was significantly higher than even that in the wild-type strain as well as the spe1-null mutant, particularly with a very continuously enhanced putrescine level, reflecting no inhibition mechanism operating in the putrescine synthesis step by any corresponding insect ODC antizymes to SlitODC in this yeast system.