Expression and localization of two-pore domain K(+) channels in bovine germ cells

Two-pore domain K(+) (K(2P)) channels that help set the resting membrane potential of excitable and nonexcitable cells are expressed in many kinds of cells and tissues. However, the expression of K(2P) channels has not yet been reported in bovine germ cells. In this study, we demonstrate for the first time that K(2P) channels are expressed in the reproductive organs and germ cells of Korean cattle. RT-PCR data showed that members of the K(2P) channel family, specifically KCNK3, KCNK9, KCNK2, KCNK10, and KCNK4, were expressed in the ovary, testis, oocytes, embryo, and sperm. Out of these channels, KCNK2 and KCNK4 mRNAs were abundantly expressed in the mature oocytes, eight-cell stage embryos, and blastocysts compared with immature oocytes. KCNK4 and KCNK3 were significantly increased in eight-cell stage embryos. Immunocytochemical data showed that KCNK2, KCNK10, KCNK4, KCNK3, and KCNK9 channel proteins were expressed at the membrane of oocytes and blastocysts. KCNK10 and KCNK4 were strongly expressed and distributed in oocyte membranes. These channel proteins were also localized to the acrosome sperm cap. In particular, KCNK3 and KCNK4 were strongly localized to the post-acrosomal region of the sperm head and the equatorial band within the sperm head respectively. These results suggest that K(2P) channels might contribute to the background K(+) conductance of germ cells and regulate various physiological processes, such as maturation, fertilization, and development.     

Relationship of Carcass Weight to Muscle Fiber Characteristics and Pork Quality of Crossbred (Korean Native Black Pig × Landrace) F2 Pigs

A total of 168 carcasses of crossbred (Korean native black pig × Landrace) F₂ pigs were divided into four carcass weight groups (A, 70–79 kg; B, 80–89 kg; C, 90–99 kg; D, 100–109 kg). The influence of carcass weight on muscle fiber characteristics and meat quality traits of pork, from the longissimus dorsi, were investigated. Carcass traits such as loin-eye area and back-fat thickness were found to increase with increasing carcass weight. Fat content, sarcomere length, drip loss, and meat color values (L*, a*, and b*) also increased with increasing carcass weight. However, moisture content and Warner–Bratzler shear force decreased with increasing carcass weight. A decrease in the compositions of type I and IIA fibers and an increase in the composition of type IIB fibers were observed with increasing carcass weight. The heavier carcasses showed type I and IIB fibers of bigger size and a smaller size of type IIA fibers. Fiber number percentage and the diameter of type IIB showed a significant positive correlation with carcass weight, fat content, and lightness (p?<?0.05). Fiber diameter of type IIB was positively correlated with loin-eye area, but was negatively correlated with moisture content. However, muscle fiber characteristics had no correlation with back-fat thickness, ultimate pH, Warner–Bratzler shear force, and b* value. In conclusion, crossbred pig which has of high composition and size of type IIB has high lightness (L* value) and water-holding capacity (drip loss). Therefore, excessively high weight of carcass has influence on pale and exudative properties in pig because of muscle fiber characteristics, especially type IIB fiber.     

Antioxidant activity and hepatoprotective effect of Schizandra chinensis Baill. Extracts containing active components in alcohol-induced HepG2 cells

The antioxidant activities and hepatoprotective effects of Schizandra chinensis Baill. extracts (SCE) were evaluated. The contents of the active components schisandrin, schisandrin C, gomisin A, and gomisin N in SCE were 8.802±1.390, 1.011±0.203, 0.954±0.191, and 3.351±0.829 mg/g, respectively. The antioxidant activity of SCE was measured based on the DPPH free radical scavenging activity and the superoxide dismutase (SOD)-like activity. The IC₅₀ values for the DPPH radical scavenging activity and SOD-like activity were 18.1 and 44.2mg/mL, respectively. The protective effect of SCE against alcohol-induced oxidative injury in HepG2 cells was investigated. Cells pretreated with SCE (100–400 μg/mL) showed an increased resistance to oxidative stress in a dose-dependent manner. Expressions of Bcl-2 and pro-caspase-3 proteins were induced by SCE in HepG2 cells. SCE can be useful for management of antioxidant and hepatoprotective effects.     

Soil Microvariation as a Source of Variability in the Wild: The Case of Secondary Metabolism in <Emphasis Type="Italic">Origanum dayi</Emphasis> Post

The volatile components of Origanum dayi Post were analyzed in 10 wild populations grown in a limited area. ANOVA tests showed no significant differences among the compositions of plants that grew in different locations, which suggests that differences in composition are of genetic origin and do not spring from environmental variation. However, the use of new statistical methods (such as use of the correlation coefficient, r, as a parametric value) revealed that, despite their reduced range of variation, most of the 22 soil properties (SPs) measured correlated with the composition of the volatile components. This analysis also indicated that the main volatile components were modified in parallel in response to SP variations. It is concluded that variations in soil properties affected the composition of volatile components in O. dayi, and that the main influencing factors were soil microelement contents and texture. This study highlights the need for highly sensitive statistical tools to determine the actual influence of environmental factors in natural environments, especially when their range of variation is small.     

Effect of induction heating on fatigue life of drive plate for dual mass flywheel

A dual mass flywheel has positive effects on noise and vibration problems, but there are still difficulties securing sufficient component durability during the development process to increase the output. In this study, the fatigue life of a drive plate, a component in the power transmission path that is often fractured by cyclic loading, is evaluated in relation to heat treatment, and the effect of heat treatment on the fatigue life is studied. For this purpose, a fatigue test and rig test are conducted on both the raw material and heat-treated material of the drive plate. Based on the fatigue material properties obtained from the fatigue tests and the boundary conditions of the rig test, a fatigue analysis is conducted to predict the fatigue life. The heat-treated material has a fatigue life five times longer than the raw material in both the rig test and fatigue analysis. The fatigue life evaluation method is validated through a comparison of the life predicted by the fatigue analysis and the test results of the rig test.     

Cross-specialty linkage and extrapolation of resource-based relative value scales

We used the fluorescent labelled dopamine D1-receptor antagonist Bodipy-SCH 23390 for the cellular localization of D1-ligand binding sites in the retinae of different vertebrates (teleosts, Xenopus, turtle, rat and rabbit). Competition experiments with unfixed cryosections of fish retina were performed to characterize the binding conditions of Bodipy-labelled SCH 23390. Tissue bound [3H]SCH 23390 was displaceable with increased amounts of bodipy-SCH 23390. The pharmacological specificity of the D1 fluorescent antagonist was determined by competition experiments with an excess of unlabelled SCH 23390. This treatment significantly reduced the level of fluorescence of the retina confirming the specificity of the binding. We observed a homogeneously distributed fluorescence signal in both plexiform layers in unfixed cryosections of fish, frog, turtle, rat and rabbit. Similar staining intensities of both plexiform layers were found in frog, turtle, rat and rabbit retina. In teleosts, the label of the outer plexiform layer was markedly more intense. Non-specific label was associated with photoreceptor outer and inner segments. The specific labelling of both plexiform layers indicates a mismatch of dopamine releasing and D1-binding sites, and suggests a possible extrasynaptic localization of the D1-receptor. The physiological significance of the observed distribution of D1-ligand binding sites is discussed with respect to the role of dopamine in controlling adaptational processes in the retina.     

Flow analysis of engine cooling system for a passenger vehicle

A numerical simulation is carried out to analyze the flow field of cooling air through the radiator and engine compartment. In order to consider the strong effect of the suction-type flow by the cooling fan at engine idling condition, a potential flow analysis is attempted by the assumption of a line sink located at the position of the cooling fan. The governing equations for steady two-dimensional, incompressible, turbulent flow are solved with the two-equationk-ε model for turbulence. The velocity profiles in the underhood engine compartment and around the front-end of a real vehicle are measured to compare with the numerical results. The agreement between the numerical and experimental results is fairly good. It is concluded that a two-dimensional computation is a fast and efficient tool for predicting the effect of front-end design on the cooling air flow through the radiator.