Hong Sun Yook

Conformational changes of myosin by gamma irradiation

Abstract Conformational and decompositional changes of bovine skeletal muscle myosin caused by gamma irradiation were studied for understanding the effects of irradiation treatment on myofibrillar proteins. Myosin solution and beef cuts were irradiated 0, 1, 3, 5 and 10 kGy. Competitive indirect enzyme linked immunosorbent assay (Ci-ELISA) showed that subunits of myosin were structurally modified with different patterns. Binding abilities of anti-myosin whole molecule and anti heavy meromyosin S-1 IgG, which were produced from rabbits, with irradiated myosin decreased in the same tendency depending upon the dose. Anti-light meromyosin IgG appeared to have the highest binding ability at 3 kGy. Irradiated beef cuts (≥5 kGy) could be identified by Ci-ELISA. Myosin solution became increasingly turbid with increasing dose. Hydrophobicity of myosin solution also increased by irradiation. Electrophoretic patterns showed that the myosin heavy chain disappeared and new bands were generated at higher molecular weight ranges.

Anti-Inflammatory Effect of Mangostenone F in Lipopolysaccharide-Stimulated RAW264.7 Macrophages by Suppressing NF-κB and MAPK Activation

Mangostenone F (MF) is a natural xanthone isolated from Garcinia mangostana. However, little is known about the biological activities of MF. This study was designed to investigate the anti-inflammatory effect and underlying molecular mechanisms of MF in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. MF dose-dependently inhibited the production of NO, iNOS, and pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) in LPS-stimulated RAW264.7 macrophages. Moreover, MF decreased the NF-κB luciferase activity and NF-κB DNA binding capacity in LPS-stimulated RAW264.7 macrophages. Furthermore, MF suppressed the NF-κB activation by inhibiting the degradation of IκBα and nuclear translocation of p65 subunit of NF-κB. In addition, MF attenuated the AP-1 luciferase activity and phosphorylation of ERK, JNK, and p38 MAP kinases. Taken together, these results suggest that the anti-inflammatory effect of MF is associated with the suppression of NO production and iNOS expression through the down-regulation of NF-κB activation and MAPK signaling pathway in LPS-stimulated RAW264.7 macrophages.

Effect of ionizing radiation on the physiological activities of ethanol extract from hizikia fusiformis cooking drips

Although the byproduct from Hizikia fusiformis industry had many nutrients, it is being wasted. In this study, the physiological activities of cooking drip extracts from H. fusiformis (CDHF) were determined to investigate the effect of a gamma and an electron beam irradiations. DPPH radical scavenging activity and tyrosinase and ACE inhibition effects of the gamma and electron beam irradiated CDHF extracts were increased with increasing irradiation dose. These were reasoned by the increase in the content of the total polyphenolic compound of CDHF by the gamma and electron beam irradiation. There were no differences for the radiation types. These results show that ionizing radiation could be used for enhancing the functional activity of CDHF which is a major by-product in Hizikia fusiformis processing, in various applications.

Effect of gamma irradiation on the microstructure and post-mortem anaerobic metabolism of bovine muscle

Abstract Experiments were performed to study the effect of gamma irradiation on morphological properties and post-mortem metabolism in bovine M . sternomandibularis with special reference to ultrastructure, shear force, pH and ATP breakdown. The shortening of sarcomere was not observed in gamma-irradiated muscle, however, the disappearance of M-line and of A- and I-bands was perceptible. During cold storage, the destruction of muscle bundles was faster in the gamma-irradiated muscle than in the non-irradiated with a dose-dependent manner. The same is true for the post mortem pH drop and ATP breakdown. So, experimental results confirmed that the anaerobic metabolism and morphological properties are noticeably affected by gamma irradiation in beef.

Microbiological Contamination of Ice Cream Commercially Available in Korea and its Irradiation Effect

아이스크림의 미생물학적 안전성, 보존성 및 위생성 향상을 위한 연구의 일환으로 시판 중인 아이스크림 제품류 및 다른 향을 가진 아이스크림의 미생물 분포도 및 감마선 조사효과를 알아보았다. 또한 시판 아이스크림에서 Listeria spp., E. coli 및 Salmonella spp.의 오염 여부를 알아보았다. 시판 중인 아이스크림 제...

Cyanidin-3-glucoside ameliorates CCl4-induced liver injury in mice

The protective effect of cyanidin-3-glucoside (C3G) against carbon tetrachloride (CCl4)-induced liver injury in mice was investigated. Administration of C3G attenuated the levels of serum aspartate aminotransferase, alanine aminotransferase, and liver lipid peroxidation in CCl4-treated mice. Histopathological examination of mouse livers showed that C3G reduced the incidence of liver lesions induced by CCl4. Moreover, C3G prevented DNA damage and decreased the protein levels of γ-H2AX in CCl4-treated mouse livers. C3G also increased the activity of the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase, which were decreased due to CCl4 administration in CCl4-treated mouse livers. C3G inhibited the expression levels of IL-6 and iNOS in CCl4-treated mice. C3G apparently protects the liver from CCl4-induced hepatic damage through antioxidant and anti-inflammatory mechanisms.