PTP1B Inhibitory and Anti-Inflammatory Effects of Secondary Metabolites Isolated from the Marine-Derived Fungus Penicillium sp. JF-55

Protein tyrosine phosphatase 1B (PTP1B) plays a major role in the negative regulation of insulin signaling, and is thus considered as an attractive therapeutic target for the treatment of diabetes. Bioassay-guided investigation of the methylethylketone extract of marine-derived fungus Penicillium sp. JF-55 cultures afforded a new PTP1B inhibitory styrylpyrone-type metabolite named penstyrylpyrone (1), and two known metabolites, anhydrofulvic acid (2) and citromycetin (3). Compounds 1 and 2 inhibited PTP1B activity in a dose-dependent manner, and kinetic analyses of PTP1B inhibition suggested that these compounds inhibited PTP1B activity in a competitive manner. In an effort to gain more biological potential of the isolated compounds, the anti-inflammatory effects of compounds 1–3 were also evaluated. Among the tested compounds, only compound 1 inhibited the production of NO and PGE₂, due to the inhibition of the expression of iNOS and COX-2. Penstyrylpyrone (1) also reduced TNF-α and IL-1β production, and these anti-inflammatory effects were shown to be correlated with the suppression of the phosphorylation and degradation of IκB-α, NF-κB nuclear translocation, and NF-κB DNA binding activity. In addition, using inhibitor tin protoporphyrin (SnPP), an inhibitor of HO-1, it was verified that the inhibitory effects of penstyrylpyrone (1) on the pro-inflammatory mediators and NF-κB DNA binding activity were associated with the HO-1 expression. Therefore, these results suggest that penstyrylpyrone (1) suppresses PTP1B activity, as well as the production of pro-inflammatory mediators via NF-κB pathway, through expression of anti-inflammatory HO-1.     

A Study on Thought of Tea of Hanjae Yi-mok＇s Da-bu

The Da-bu of Hanjae Lee mok （1471-1498） is known as an original masterpiece,which is predominantly documented in Korean tea books.He had always spared no effort to put Confucianists＇ theories and thoughts into practice during his 28-year career.Da-bu tea magnificently reflected his concepts of Confucianism in conjunction with tea-drinking activities.The main contents of Da-bu have included written authors,tea species and production,landscape of tea cultivation,tea plants and leaves,ways of tea-drinking and three-grade tea,tea song of seven cups,5 merits and 6 moralities of tea,benefits of tea-drinking,tea comprehension,etc.According to the views of contents,tea of Hanjae Leemok is the only partner with which we can share life and it can also be beneficial to healthy diets.Not only does it have become part of our daily life,but also be a medicine for our physical and mental disease.He composed the tea song of seven cups,which sufficiently expressed a real practice of the pursued ideal state of Confucianism and Taoism.He also promoted a drinking tea for health enrichment of Confucianists.According to the analytical results of Da-bu,Hanjae＇s tea has recognizably become the personally real practice of Confucianism and state.He had reached the enlightenment for the state of birth and death.After consuming tea,his body and mind immediately changed to the state of joys and wonderland,and also he illustrated that this feeling is not a one-off state,it always comes out whenever drinking.Therefore,based on Hanjae Lee mok,tea drinking is not only the regiment for healthy benefits,but also it is a training method,＂ Dado in My Heart＂,for individuals to train their mind,body,and morality.     

Relation between the dynamic modulus of elasticity and the static modulus of elasticity,the modulus of rupture of mandarin peel–sawdust composite board

This study was conducted to determine the relation between the dynamic modulus of elasticity and the static modulus of elasticity, and the relation between the dynamic modulus of elasticity and the modulus of rupture of mandarin peel–sawdust composite boards. The result of this study was as follows: There was highly close linear correlation between the dynamic modulus of elasticity and the static modulus of elasticity, modulus of rupture of the mandarin peel–sawdust composite boards with the density of 0.4, 0.5 and 0.6 g/cm³, and the mandarin peel content of 10, 20, 30 and 40%, thus, the static modulus of elasticity and the modulus of rupture can be predicted from the dynamic modulus of elasticity measured by free vibration test using resonance frequency.     

Development of immunoassays for the detection of kanamycin in veterinary fields

Monoclonal antibody against kanamycin was prepared, and competitive direct ELISA and immunochromatographic assay were developed using the antibody to detect kanamycin in animal plasma and milk. The monoclonal antibody produced was identified to be IgG1, which has a kappa light chain. No cross-reactivity of the antibody was detected with other aminoglycosides, indicating that the monoclonal antibody was highly specific for kanamycin. Based on competitive direct ELISA, the detection limits of kanamycin were determined to be 1.1 ng/ml in PBS, 1.4 ng/ml in plasma, and 1.0 ng/ml in milk. The concentration of intramuscularly injected kanamycin was successfully monitored in rabbit plasma with competitive direct ELISA. Based on the colloidal gold-based immunochromatographic assay, the detection limits of kanamycin were estimated to be about 6-8 ng/ml in PBS, plasma, and milk. The immunochromatographic assay would be suitable for rapid and simple screening of kanamycin residues in veterinary medicine. Screened positives can be confirmed using a more sensitive laboratory method such as competitive direct ELISA. Therefore, the assays developed in this study could be used to complement each other as well as other laboratory findings. Moreover, instead of slaughtering the animals to obtain test samples, these methods could be applied to determine kanamycin concentration in the plasma of live animals.     

The role of rpoS,hmp, and ssrAB in Salmonella enterica Gallinarum and evaluation of a triple-deletion mutant as a live vaccine candidate in Lohmann layer chickens

Salmonella enterica Gallinarum (SG) causes fowl typhoid (FT), a septicemic disease in avian species. We constructed deletion mutants lacking the stress sigma factor RpoS, the nitric oxide (NO)-detoxifying flavohemoglobin Hmp, and the SsrA/SsrB regulator to confirm the functions of these factors in SG. All gene products were fully functional in wild-type (WT) SG whereas mutants harboring single mutations or a combination of rpoS, hmp, and ssrAB mutations showed hypersusceptibility to H₂O₂, loss of NO metabolism, and absence of Salmonella pathogenicity island (SPI)-2 expression, respectively. A triple-deletion mutant, SGΔ3 (SGΔrpoSΔhmpΔssrAB), was evaluated for attenuated virulence and protection efficacy in two-week-old Lohmann layer chickens. The SGΔ3 mutant did not cause any mortality after inoculation with either 1 × 10⁶ or 1 × 10⁸ colony-forming units (CFUs) of bacteria. Significantly lower numbers of salmonellae were recovered from the liver and spleen of chickens inoculated with the SGΔ3 mutant compared to chickens inoculated with WT SG. Vaccination with the SGΔ3 mutant conferred complete protection against challenge with virulent SG on the chickens comparable to the group vaccinated with a conventional vaccine strain, SG9R. Overall, these results indicate that SGΔ3 could be a promising candidate for a live Salmonella vaccine against FT.     

我国数控机床的现状及发展趋势

论述我国数控机床发展的过程与现状,对数控机床的发展趋势进行了探讨,提出了我国数控机床发展的对策。     

The fish fauna of mountain streams in South Korean national parks and its significance to conservation of regional freshwater fish biodiversity

The fish fauna of mountain streams in the Jiri (440 km²) and Seorak (373 km²) National Park areas of South Korea was investigated from September 1998 to May 2001. A total of 5979 fish were collected and classified into 22 families and 60 species from both national parks. At Jiri, 30 species in 12 families of fishes were collected, while at Seorak there were 42 species in 17 families. Zacco temmincki [relative abundance (RA) 47.9%] was dominant at both parks. Subdominant species were Rhynchocypris kumkangensis (RA 10.8%), Zacco platypus (RA 9.4%), and Pungtungia herzi (RA 5.3%). A total of 20 species were found to be Korean endemic species, representing seven families. The relative abundance of Korean endemic species was higher at Seorak (30.5%) than Jiri (18.5%). One exotic species (Oncorhynchus mykiss) and two species translocated outside their native catchments (Hypomesus nipponensis and Coreoperca herzi) were collected. The proportion of Korean endemic freshwater fish species in both parks (33.3%) was higher than the overall proportion on the Korean peninsula (23.6%). Within the 14 South Korean mountain-area national parks as a whole, larger parks tend to have higher fish diversity. We conclude that South Korean national parks are important for conservation of the regional fish fauna, especially for endemic and endangered species. Current threats to conservation of fishes within South Korean national parks are identified and management solutions are suggested.     

Stability of chitosan nanoparticles for L-ascorbic acid during heat treatment in aqueous solution

This study investigated the stability and characteristics of L-ascorbic acid (AA)-loaded chitosan (CS) nanoparticles during heat processing in aqueous solutions. AA-loaded CS nanoparticles were prepared by ionic gelation of CS with tripolyphosphate (TPP) anions. The smallest CS nanoparticles (170 nm) were obtained with a CS concentration of 1.5 mg/mL and a TPP concentration of 0.6 mg/mL. As the concentration of AA increased from 0.1 to 0.3 mg/mL, the particle size increased, while the zeta potential decreased, and the encapsulation efficiency of AA remained within a fixed range (10-12%). During heat processing at various temperatures, the size and zeta potential of the particles decreased rapidly in the first 5 min and then slowly fell to the regular range. At the beginning of the release profiles, the burst release-related stability of the surface increased with the temperature. Then, the release of the internal AA was constantly higher with a longer release time. Consequently, it was confirmed that the stability of AA-loaded CS nanoparticles was affected by temperature but that the internal stability was greater than the surface stability. These results demonstrate the stability of CS nanoparticles for AA during heat processing and suggest the possible use of AA-loaded CS nanoparticles to enhance antioxidant effects because of the continuous release of AA from CS nanoparticles in food processing.     

Effect of Sucrose on Glass Transition,Gelatinization, and Retrogradation of Wheat Starch

Differential scanning calorimetry (DSC) was used to study the effect of sucrose on wheat starch glass transition, gelatinization, and retrogradation. As the ratio of sucrose to starch increased from 0.25:1 to 1:1, the glass transition temperature (T_g, T_g′) and ice melting enthalpy (ΔH_ice) of wheat starch‐sucrose mixtures (with total moistures of 40–60%) were decreased to a range of −7 to −20°C and increased to a range of 29.4 to 413.4 J/g of starch, respectively, in comparison with wheat starch with no sucrose. The T_g′ of the wheat starch‐sucrose mixtures was sensitive to the amount of added sucrose, and detection was possible only under conditions of excess total moisture of >40%. The peak temperature (T_m) and enthalpy value (ΔH_G) for gelatinization of starch‐sucrose systems within the total moisture range of 40–60% were increased with increasing sucrose and were greater at lower total moisture levels. The T_g′ of the starch‐sucrose system increased during storage. In particular, the significant shift in T_g′ ranged between 15 and 18°C for a 1:1 starch‐sucrose system (total moisture 50%) after one week of storage at various temperatures (4, 32, and 40°C). At 40% total moisture, samples with sucrose stored at 4, 32, and 40°C for four weeks had higher retrogradation enthalpy (ΔH) values than a sample with no sucrose. At 50 and 60% total moisture, there were small increases in ΔH values at storage temperature of 4°C, whereas recrystallization of samples with sucrose stored at 32 and 40°C decreased. The peak temperature (T_p), peak width (δT), and enthalpy (ΔH) for the retrogradation endotherm of wheat starch‐sucrose systems (1:0.25, 1:0.5, and 1:1) at the same total moisture and storage temperature showed notable differences with the ratio of added sucrose. In addition, T_p increased at the higher storage temperature, while δT increased at the lower storage temperature. This suggests that the recrystallization of the wheat starch‐sucrose system at various storage temperatures can be interpreted in terms of δT and T_p.     

几种饲料添加剂对产蛋鸡生产性能、生化指标的影响

以基础日粮中添加土霉素和低聚木糖、产酶益生素、中药"绿益康"3种生物制剂为处理.研究各处理组对产蛋鸡生产性能、生化指标的影响.试验表明:3种生物制剂处理组的平均产蛋率和料蛋比均显著优于空白对照组和土霉素处理组(P<0.05);同时3处理组谷丙转氨酶活性、甘油三脂含量、低密度脂蛋白含量、血清尿素氮、血糖含量与空白对照组和土霉素处理组相比都有所降低,总胆固醇含量与空白对照组和土霉素处理组相比显著降低.综合各项指标,以添加0.01%低聚木糖的试验2组效果为最佳.