[show abstract][hide abstract] ABSTRACT: The characteristics of a lectin from the marine bivalve Ruditapes philippinarum (Manila clam) were investigated in this study. A method was developed for the isolation of the Manila clam lectin (MCL). Affinity chromatography using mucin-Sepharose, ion-exchange chromatography with DEAE-Toyoperl, and gel filtration with Superose 6 were used for MCL isolation. SDS-PAGE showed that the MCL protein had a molecular mass of 138 kDa, and consisted of 74-, 34-, and 30-kDa subunits. The native lectin in solution behaved as a 274-kDa protein in gel filtration chromatography. The lectin activity of MCL was Ca2+ -dependent, and the optimal Ca2+ concentration for MCL activity was 20 mM. MCL activity was stable between pH 6 and pH 9, and was temperature-dependent; incubation of MCL at 90 degrees C led to irreversible denaturation. The activity of MCL was not inhibited by the presence of monosaccharides, such as Man, Fuc, Gal, Glc, GlcNAc, and NeuNAc. In contrast, the lectin activity of MCL was strongly inhibited by the presence of porcine mucins. MCL activity was also inhibited by N-acetyl-d-galactosamine, human embryonic alpha-1-acid glycoprotein, and highly branched mannans from marine halophilic bacteria. It appears that MCLs have unusual carbohydrate specificities for N-acetyl-d-galactosamine, which contains both mucin-type carbohydrate chains and highly branched mannans. Immunofluorescence staining revealed that MCL was bound to the surfaces of purified hypnospores from Perkinsus sp., which is a protozoan parasite of Manila clams.
Fish & Shellfish Immunology 05/2004; 16(4):487-99. · 2.96 Impact Factor
[show abstract][hide abstract] ABSTRACT: The cytotoxic activity of oxysterols, 7 beta-hydroxycholesterol (7 beta-OHC) and 25-hydroxycholesterol (25-OHC), has been evaluated using various leukemia cell lines. Among the tested cell lines, both oxysterols showed the highest cytotoxicity to THP-1, human monocytic leukemia cell line. These oxysterols induced apoptosis through down-regulation of Bcl-2 expression and activation of caspases. Also, the oxysterols showed the accumulation at G(2)/M phase of cell cycle through down-regulation of cyclin B1 expression. Taken together, these results indicated that both 7 beta-OHC and 25-OHC inhibited the proliferation of THP-1 cells through apoptosis and cell cycle accumulation at G(2)/M phase.
Life Sciences 03/2003; 72(12):1389-99. · 2.56 Impact Factor
[show abstract][hide abstract] ABSTRACT: Artemisia capillaris is a perennial herb that belongs to the family Campositae spp, and has been utilized in Korea for the treatment of abdominal pain, hepatitis, chronic liver disease, and coughing. The anti-inflammatory activity of the ethanol extract of A. capillaris (EtEAC) was investigated in this study. EtEAC did not affect the viability of various cells in a concentration range of 0-200 μg/mL. The DPPH radical scavenging ability of 10 μg/mL of EtEAC was comparable to that of 10 μg/mL of catechin. EtEAC exerted an anti-inflammatory effect on the mRNA expression levels of typical inflammatory cytokines (IL-6, IL1β) and cyclooxygenase-2 in LPS-stimulated RAW 264.7 cells. Additionally, EtEAC reduced nitric oxide (NO) production via the downregulation of inducible nitric oxide synthase transcription, rather than by scavenging NO. EtEAC exerted its anti-inflammatory effects by suppressing the activation of p38 and ERK at 200 μg/mL in LPS-stimulated RAW 264.7 cells.
Journal of the Korean Society for Applied Biological Chemistry 53(3). · 0.43 Impact Factor