Mechanisms of protein S-thiolation and dethiolation

Mechanisms of S-thiolation and dethiolation of creatine kinase and glycogen phosphorylase b were studied. S-thiolation of the two proteins was initiated by oxyradicals generated by xanthine oxidase in reaction mixtures containing reduced glutathione (GSH). Both proteins were extensively modified under the conditions in which the oxidation of glutathione was inadequate to cause S-thiolation by thiol-disulfide exchange. Creatine kinase was both S-thiolated and non-reducibly oxidized at low GSH concentration, but with adequate GSH, oxidation was prevented while S-thiolation was still active. S-thiolation of glycogen phosphorylase b was not significantly affected by GSH concentration and non-reducible oxidation was not observed. The results suggested that protein sulfhydryls could react more actively than GSH with superoxide anion. Thus, oxyradicals may react with protein sulfhydryls resulting in S-thiolation by a mechanism that involves the reaction of an activated protein thiol with reduced glutathione. Dethiolation of phosphorylase b was actively catalyzed by a cardiac extract by both an NADPH-dependent and a GSH-dependent process. In contrast, creatine kinase was actively dethiolated only by GSH nonenzymatically. Thus, two proteins were dethiolated by different mechanisms. Cells seem to have very high capacity for dethiolation by these three mechanisms. The NADPH-dependent dethiolase had both a high molecular weight component and a low molecular weight component. These two components were sensitive to inhibition by phenylarsine oxide and the inhibition was reversed by addition of a dithiol. Therefore, the properties of these components were similar to thioredoxin and thioredoxin reductase. Dethiolation of phosphorylase b was also demonstrated by Escherichia coli thioredoxin with either dithiothreitol or cardiac extract and NADPH as a reducing power, while creatine kinase was not dethiolated by this process. In contrast, GSH-dependent dethiolation required a single component of low molecular weight, and it was less sensitive to phenylarsine oxide inhibition;Therefore, protein S-thiolation and dethiolation play an important role in preventing oxidative damage to cellular system during oxidative stress

Identification of keratinolytic function in Chryseobacterium camelliae Dolsongi-HT1 isolated from Green Tea

Keratin forms a major component of the epidermis, hair, feathers, nails, scales and etc. However, old keratins on the skin are not preferred for the beauty purpose. Therefore, in the highly efficient and low irritative method to remove old keratin on the skin is highly desired. For this purpose, one of the appropriate methods is the enzymatic lysis of keratin. To screen a novel keratinase, a novel microorganism having keratinolytic activity was isolated by enrichment culture. Newly screened microorganism was isolated from green tea in dolsong-i tea garden, Jeju and identified as Chryseobacterium camelliae Dolsongi-HT1. The keratinase activity of C. camelliae Dolsongi-HT1 was confirmed in the culture media. The effect of pH and temperature were studied using cell culture media. Crude keratinase showed high activity over a wide range of temperature (37 to 60°C) and showed the highest activity at 50°C. Optimum pH of keratinase activity of crude keratinase was pH 8. Interestingly, this enzyme activity was maintained over 50% at pH 6. This feature is promising for the application to cosmetics. The effect of nitrogen source for cell culture was also investigated. Among the various nitrogen sources, the highest keratinase activity (relative activity of 366.4%) was detected when cells were cultured using tryptone extract. To study the keratinolytic activity effect of keratin on the skin, the keratin of skin was obtained using tape stripping. It was found that the structure of keratin was degraded by crude keratinase. To identify the keratinase, the complete genome of C. camelliae Dolsongi-HT1 was sequenced. Because keratinases are regarded as serine or metalloprotease group, we searched for those proteases in the C. camelliae Dolsongi-HT1 genome sequence. As s result, over twenty putative keratinases could be identified. Further research to identify desired keratinases should be performed

Sargassum fulvellum

Ultraviolet (UV) radiation has been reported to induce cutaneous inflammation such as erythema and edema via induction of proinflammatory enzymes and mediators. Sargassum fulvellum is a brown alga of Sargassaceae family which has been demonstrated to exhibit antipyretic, analgesic, antiedema, antioxidant, antitumor, fibrinolytic, and hepatoprotective activities. The purpose of this study is to investigate anti-inflammatory effects of ethylacetate fraction of ethanol extract of Sargassum fulvellum (SFE-EtOAc) in HaCaT keratinocytes and BALB/c mice. In HaCaT cells, SFE-EtOAc effectively inhibited UVB-induced cytotoxicity (60 mJ/cm2) and the expression of proinflammatory proteins such as cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), and inducible nitric oxide synthase (iNOS). Furthermore, SFE-EtOAc significantly reduced UVB-induced production of proinflammatory mediators including prostaglandin E2 (PGE2) and nitric oxide (NO). In BALB/c mice, topical application of SFE-EtOAc prior to UVB irradiation (200 mJ/cm2) effectively suppressed the UVB-induced protein expression of COX-2, iNOS, and TNF-α and subsequently attenuated generation of PGE2 and NO as well. In another experiment, SFE-EtOAc pretreatment suppressed UVB-induced reactive oxygen species production and exhibited an antioxidant potential by upregulation of antioxidant enzymes such as catalase and Cu/Zn-superoxide dismutase in HaCaT cells. These results suggest that SFE-EtOAc could be an effective anti-inflammatory agent protecting against UVB irradiation-induced skin damages

Autonomous control of terminal erythropoiesis via physical interactions among erythroid cells

AbstractIn vitro erythropoiesis has been studied extensively for its application in the manufacture of transfusable erythrocytes. Unfortunately, culture conditions have not been as effective as in vivo growth conditions, where bone marrow macrophages are known to be a key regulator of erythropoiesis. This study focused on the fact that some erythroblasts are detached from macrophages and only contact other erythroblasts. We hypothesized that additional factors regulate erythroblasts, likely through either physical contact or secreted factors. To further elucidate these critical factors, human erythroblasts derived from cord blood were cultured at high density to mimic marrow conditions. This growth condition resulted in a significantly increased erythroid enucleation rate and viability. We found several novel contact-related signals in erythroblasts: intercellular adhesion molecule-4 (ICAM-4) and deleted in liver cancer-1 (DLC-1). DLC-1, a Rho-GTPase-activating protein, has not previously been reported in erythroid cells, but its interaction with ICAM-4 was demonstrated here. We further confirmed the presence of a secreted form of human ICAM-4 for the first time. When soluble ICAM-4 was added to media, cell viability and enucleation increased with decreased nuclear dysplasia, suggesting that ICAM-4 is a key factor in contact between cells. These results highlight potential new mechanisms for autonomous control of erythropoiesis. The application of these procedures to erythrocyte manufacturing could enhance in vitro erythrocyte production for clinical use

Relationship between Work Hours and Smoking Behaviors in Korean Male Wage Workers

OBJECTIVES: The purposes of this study are 1) to measure the prevalence of smoking according to weekly work hours by using data from the Korean Labor and Income Panel Study (KLIPS), and 2) to explain the cause of high smoking prevalence among those with short or long work hours by relative explanatory fraction. METHODS: Data from a total of 2,044 male subjects who responded to the questionnaire in the 10th year (2007) and 11th year (2008) of the Korean Labor and Income Panel Study were used for analysis. Current smoking, smoking cessation, continuous smoking, start of smoking, weekly work hours, occupational characteristics, sociodemographic and work-related factors, and health behavior-related variables were analyzed. Log-binomial regression analysis was used to study the relationship between weekly work hours and smoking behaviors in terms of the prevalence ratio. RESULTS: The 2008 age-adjusted smoking prevalence was 64.9% in the short work hours group, 54.7% in the reference work hours group, and 60.6% in the long work hours group. The smoking prevalence of the short work hours group was 1.39 times higher than that of the reference work hours group (95% confidence interval of 1.17-1.65), and this was explained by demographic variables and occupational characteristics. The smoking prevalence of the long work hours group was 1.11 times higher than that of the reference work hours group when the age was standardized (95% confidence interval of 1.03-1.19). This was explained by demographic variables. No independent effects of short or long work hours were found when the variables were adjusted. CONCLUSION: Any intervention program to decrease the smoking prevalence in the short work hours group must take into account employment type, job satisfaction, and work-related factors

Eco-Innovation Indices as Tools for Measuring Eco-Innovation

Measuring eco-innovation helps us understand the overall trends and raises awareness in society. Measuring eco-innovation at the national level and making comparisons across countries may allow us to benchmark performance and foster policy learning. This paper assesses two indices developed in two different regions: The ASEM Eco-Innovation Index (ASEI) by the ASEM SMEs Eco-Innovation Center, based in Republic of Korea; and the Eco-Innovation Scoreboard (Eco-IS) developed by the Eco-Innovation Observatory, based in the European Union. This paper aims to examine and compare the features of both and attempts to obtain insights on their strengths and weaknesses. Towards this aim, our paper assesses those scoreboards against four criteria stemming from innovation analysis: (1) relevance of areas and stakeholders covered; (2) ability to indicate changes; (3) directions towards common goals; and (4) ability to facilitate further changes. We conclude both are promising, despite data shortages, and have great potential to contribute towards the sustainable development goals (SDGs), particularly with regard to the SDGs on sustainable industrialization and sustainable consumption and production. In comparison, the ASEI covers more countries than the Eco-IS. However, the ASEI has limitations on measuring indicators due to limited data availability in Asian countries. The Eco-IS is closely linked with the regional and national policies for eco-innovation in Europe, while the ASEI’s impact appears more limited, as of now. In conclusion, the research results give insights into key areas, goals and applications of eco-innovation indices, and can help upgrading eco-innovation indices. This research helps interpret the scores of two indices better and facilitate application of the scores in the multiple ways. It is expected that this research contributes to developing and modifying a global eco-innovation index and enhancing the ability of these indices to facilitate eco-innovation strategies at national levels and across relevant actors

HOW CAN WE TEACH STUDENT TO ESTIMATE VERTICAL JUMP HEIGHTS USING GROUND REACTION FORCE DATA

The purpose of this study was to estimate vertical jump heights using ground reaction force (GRF) data and to suggest one practical example of biomechanical theory application to a real human motion. Vertical jump heights of impulse and flight time method were statistically smaller than three-dimensional video method. The causes of height differences seemed mainly from the fact that impulse was used to move jumper into the horizontal direction as well as into the vertical direction. Other important factors for accurate height calculation are jumper's mass and threshold value of GRF data collection. Vertical jump height calculation with GRF data showed an example of practical application of biomechanical theory to human motion and demonstrated a way of GRF equipment use for effective biomechanical theory education