Yoo Kyeong Kim

Neurotoxic Effects of Bisphenol AF on Calcium-Induced ROS and MAPKs

Bisphenol AF (BPAF), a newly introduced chemical structurally related to bisphenol A, is used extensively in fluoroelastomers and polyesters, and has been known to induce estrogen-dependent responses. However, the toxicity of BPAF is largely unknown except for its endocrine-related effects. In this study, we investigated the neurotoxicity of BPAF and underlying mechanisms of action using hippocampal cell line (HT-22) and mouse primary neuronal cells. We found that BPAF induced apoptosis in both HT-22 and primary neuronal cells. In order to clarify the underlying mechanisms of BPAF-induced apoptosis, various signaling molecules were evaluated. BPAF increased the level of intracellular calcium, followed by the generation of reactive oxygen species (ROS). BPAF upregulated the phosphorylation of mitogen-activated protein kinase: extracellular signal-regulated kinase, p38 and c-Jun N-terminal kinase (JNK), and nuclear translocation of nuclear factor-κB. Using specific inhibitors, we confirmed that calcium, ROS, p38, and JNK mediated the BPAF-induced apoptosis. In addition, BPAF inhibited microglial activation in a microglia/neuroblastoma coculture model by the reduction of nitric oxide production. We found that BPAF interrupted the normal physiologic functions of microglia at non-toxic levels. Taken together, our results suggest that BPAF, the substitute of BPA, also have neurotoxic properties.

Purification, characterization, and properties of an alkaline protease produced by Serratia marcescens S3‐R1 inhabiting Korean ginseng rhizosphere

BACKGROUND An alkaline protease produced by the Serratia marcescens S3-R1 which inhabits in the Korean ginseng rhizosphere was investigated. The purposes of this study were to characterize and purify the bacterial enzyme by four different purification steps: precipitation of enzyme fraction by ammonium sulfate, loading the enzyme pellets on a DEAE-Sepharose anion-exchange chromatograph, separation of the fraction containing enzyme activity by fast protein liquid Mono Q chromatography and identification of the single-band fraction by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and then quantification of the single-band fraction by reverse-phase high-performance liquid chromatography. RESULTS The molecular weight of the purified protease was estimated as 50 308 Da by matrix-assisted laser desorption ionization time-of-flight analysis. The N-terminal amino acid sequence of the protease was identified as Ala-Val-Thr-Ile-Glu-Asp-Ala-Val-Asp-Asp, and the enzyme belongs to the metalloprotease family. The optimal activities of the protease occurred at pH 7-9 and a temperature 40 °C. The ranges of pH and thermal stability of the enzyme were at 7-10 and 30-40 °C, respectively. CONCLUSION The alkaline protease was successfully purified and characterized from the bacterium Serratia marcescens S3-R1, which has potential for industrial application, including milk protein hydrolysates.

Moderating Effect of Health Motivation, Health Concern and Food Involvement on the Relationship between Consumption Value and Purchasing Intentions of Healthy Functional Food

Dept. of Home Economics Education, Kyungpook National University, Daegu 702-701, KoreaAbstractThe purpose of this study was to identify the influence of consumption value on healthy functional food choice. Also, this study explored the role of health motivation, health concern, and food involvement as a moderating variable in the relationship between consumption value and healthy functional food choice. A total of 281 responses were collected using on-site survey (response rate 96.0%) from college students in Daegu, Gyeoungbuk Province. The questionnaire contained questions on consumption value, health motivation, health concern, food involvement, and purchasing intention of healthy functional food. The respondents rated the items using a 5-point scale from 1 (strongly disagree) to 5 (strongly agree). According to the confirmatory factor analysis, item evaluating using factor loading resulted in the retention of 25 consumption value items loading on seven factors, four health motivation items loading one factor, six health concern items loading on one factor, and four food involvement items loading on one factor with an internal consistency. Results of stepwise regression found that social value-I, emotional, functional, epistemic, and conditional values among consumption value determined the purchasing intention of healthy functional food. Results of hierarchical regression showed that health concern had a positive effect on the relationship between social value-I and purchasing intention of healthy functional food.Key words: healthy functional food choice, purchasing intention, moderating effect

Pepper Seed Extract Suppresses Invasion and Migration of Human Breast Cancer Cells

This study was performed to determine the antimetastatic activities of chili pepper seed on human breast cancer cells. The water extract of chili pepper seeds was prepared and it contained a substantial amount of phenols (131.12 mg%) and no capsaicinoids. Pepper seed extract (PSE) suppressed the proliferation of MDA-MB-231 and MCF-7 cells at the concentration of 10, 25, and 50 μg/ml (MDA-MB-231: IC50 = 20.1 μg/ml, MCF-7: IC50 = 14.7 μg/ml). PSE increased the expression level of E-cadherin up to 1.2-fold of the control in MCF-7 cells. PSE also decreased the secretion of matrix metalloproteinase (MMP)-2 and MMP-9 in MDA-MB-231 and MCF-7 cells at the concentration of 25 and 50 μg/ml. PSE treatment significantly suppressed the invasion of MDA-MB-231 and MCF-7 cells in a dose-dependent manner. The motility of cancer cells was apparently retarded in the wound healing assay by the PSE treatment. Although our data collectively demonstrate that PSE inhibits invasion and migration of breast cancer cells, further study is needed to identify specific mechanisms and bioactive components contributing to antimetastatic effects of chili pepper seed.

Alcohol-induced bone degradation and its early detection in the alcohol-fed castrated rats

The objective of this study was to examine alcohol-induced changes of bone in hormone-deficient males using the developed method. In the process of bone resorption, type I collagen crosslinking molecules, pyridinoline (PYD), are released into the circulation and cleared by the kidneys. 2H2O as a tracer has been applied to measure the synthesis rates of slow-turnover proteins and successfully applied to bone collagen synthesis in our hormone deficiency rats. This study demonstrated for the first time, the early changes of the femur bone degradation in hormone-deficient male individuals, more influenced by alcohol through histopathological study, serum PYD assay, and 2H2O labeling. We also observed that serum PYD was a sensitive pathological marker of bone degradation in castrated osteoporosis males and the unique features of 2H2O labeling to measure the bone turnover collagen synthesis rates were excellent markers of bone degradation and aging.