UPRRP College of Natural Sciences

About: UPRRP College of Natural Sciences is a based out in . It is known for research contribution in the topics: Apoptosis & Population. The organization has 9323 authors who have published 11826 publications receiving 284172 citations.

Antioxidant activity of extracts from Alpinia katsumadai seed.

Abstract: Alpinia katsumadai (Zingiberaceae) has been widely used in traditional Chinese medicine to treat a variety of conditions such as emesis and gastric disorders. However, very little is known about the cellular actions by which this plant mediates its therapeutic effects. Various aspects of antioxidant activity were evaluated in a total extract derived from Alpinia katsumadai seed in this study. Relatively high levels of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were detected in the total extract (IC(50) 1.6 microgram/mL). Other known compounds such as (-)-epigallocatechine-3-gallate (EGCG) and resveratrol showed IC(50) values of <0.8 and 4.8 microgram/mL, respectively. The total extract also enhanced the viability of Chinese hamster lung fibroblast (V79-4) cells and inhibited H(2)O(2)-induced apoptosis. The total extract of Alpinia katsumadai also dose-dependently enhanced the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in V79-4 cells, and these effects were comparable to other antioxidant compounds such as EGCG and resveratrol. Taken together, our findings show that Alpinia katsumadai contains significant antioxidant activity.

Characteristics of the cell membrane fluidity, actin fibers, and mitochondrial dysfunctions of frozen-thawed two-cell mouse embryos.

Abstract: Physical and chemical alterations caused by the freezing and thawing and their effects on survivals/developments in vitro were investigated. Of a total of 452 two-cell mouse embryos, the overall survival rate of the frozen-thawed embryos was 76.1% (344/452). The blastocyst formation of the frozen-thawed embryos was 32.6% (44/136) compared to 74.5% (117/157) in the fresh embryos (P < 0.05). The total number of cells in a blastocyst also decreased from 96.0 ± 19.0 (n = 26) in the fresh embryos to 42.0 ± 11.34 (n = 30) in the frozen-thawed embryos (P < 0.05). Fluorescence recovery after photobleaching (FRAP) measurement revealed about 5-fold decrease in the cell membrane fluidity with a characteristic time constant (τ) of 1.46 ± 0.13 sec (n = 5) in the frozen-thawed embryos as opposed to 0.28 ± 0.04 sec (n = 5) in the fresh embryos (P < 0.05). The relative amount of H2O2 in an embryo as quantified by the fluorescence intensity of 2′,7′-dichlorofluorescein (DCF) showed 62.8 ± 23.5 (n = 24) and 34.2 ± 14.5 (n = 20) in the frozen-thawed embryos and in the fresh embryos, respectively (P < 0.05). The distribution of actin filaments in the frozen-thawed embryos revealed an uneven distribution, particularly discontinuities at the “actin band,” which contrasted to an even distribution shown in the fresh embryos. Mitochondrial staining by Rhodamine 123 showed that there was no significant difference between the two treatments in the number and in the distribution of viable mitochondria, but a marked aggregation was seen in the arrested embryos. No Annexin V binding was detected in two-cell or four-cell embryos while the binding was positive in the arrested embryos. The mitochondrial membrane potential measured by a membrane potential-sensitive fluorescent probe 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazol- carbocyanine iodide (JC-1) revealed a marked depolarization in the frozen-thawed embryos. Finally, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end-labeling (TUNEL) was employed to quantify the DNA fragmentation. In 75.0% cells of blastocysts (n = 24) in the frozen-thawed embryos, the DNA fragmentation was detected as opposed to 37.0% in the fresh embryos (n = 20) (P < 0.05). Taken together, it is proposed that during the cryopreservation, two-cell mouse embryos are subjected to physical and chemical alterations, including destruction of the cell membrane integrity, redistribution of actin fibers, mitochondrial depolarizations, and increased reactive oxygen species (ROS) productions, which then may trigger the apoptotic cascade leading to a decrease in the survival rate and in the developmental rate of the embryos. Mol. Reprod. Dev. 61:466–476, 2002. © 2002 Wiley-Liss, Inc.

Rapid evolution of low-pathogenic H9N2 avian influenza viruses following poultry vaccination programmes.

Abstract: To investigate whether currently circulating H9N2 avian influenza viruses (AIVs) in domestic poultry have evolved in Korean poultry since 2007, genetic and serological comparisons were conducted of H9N2 isolates from poultry slaughterhouses from January 2008 to December 2009. The isolation rate was relatively low in 2008 but increased gradually from January 2009 onwards. Genetic and phylogenetic analyses revealed that reassortant viruses had emerged, generating at least five novel genotypes, mostly containing segments of a previously prevalent domestic H9N2 virus lineage (Ck/Korea/04116/04-like). It was noteworthy that the N2 genes of some H9N2 isolates (genotypes D, E and F) were derived from those of H3N2-like viruses commonly isolated among domestic ducks in live-poultry markets. Animal challenge studies demonstrated that the pathogenicity of Ck/Korea/SH0906/09 (genotype B) and Ck/Korea/SH0912/09 (genotype F) in domestic avian species was altered due to reassortment. Furthermore, serological analysis revealed that the isolates were antigenically distinct from previous Korean H9N2 viruses including Ck/Korea/01310/01. Such antigenic diversity was illustrated further in experiments using H9N2-immunized chickens, which could not inhibit the replication and transmission of challenge viruses from each genotype. These results suggest that H9N2 viruses from domestic poultry have undergone substantial evolution since 2007 by immune selection as a result of vaccinal and natural immunity, coupled with reassortment. Taken together, this study demonstrates that periodical updating of vaccine strains, based on continuous surveillance data, is an important issue in order to provide sufficient protectivity against AIV infections.