Cisplatin inactivation of caspases inhibits death ligand-induced cell death in vitro and fulminant liver damage in mice

Cisplatin is a platinum-containing chemotherapeutic drug that has been widely used to treat various human cancers. It acts by forming inter- and intracross-links of DNA, which is believed to be a major cause for its therapeutic efficacy. However, little attention has been paid to the effect of cisplatin on death ligand-induced cell death. Here we demonstrate that cisplatin inhibits death ligand-induced cell death in cell lines in a p53-independent manner. This inhibitory effect of cisplatin on cell death is direct, whereby cisplatin forms a complex with caspases leading to their inactivation. The cisplatin-caspase complex is reversed by the addition of reducing agent dithiothreitol, and caspase activity is regained. In addition, cisplatin shows a death-inhibition effect in in vivo animal models of fulminant liver damage induced by Fas activation and lipopolysaccharide-induced liver shock mediated by tumor necrosis factor-alpha. Together, we demonstrate that cisplatin inhibits cell death induced by death ligands in cell lines and in mice through caspase inactivation.     

Characterization of a putative cis-regulatory element that controls transcriptional activity of the pig uroplakin II gene promoter

Vaspin, an adipocytokine recently identified in a rat model of type 2 diabetes, has been suggested to have an insulin-sensitizing effect. However, the exact mechanism underlying this action has not been fully elucidated. Furthermore, the specific function of vaspin is largely unknown, especially in vascular cells. We examined whether vaspin affects the insulin-signaling pathway in cultured endothelial cells and is capable of preventing free fatty acid (FFA)-induced apoptosis in endothelial cells through its insulin sensitizing effect, specifically, through its stimulatory effect on PI3-kinase/Akt signaling pathways. Vaspin significantly increased Akt phosphorylation and prevented the impairment of Akt phosphorylation by linoleic acid (LA) in insulin-stimulated endothelial cells, which effects were abolished by pretreatment with the PI3-kinase inhibitor, Wortmannin. Moreover, pretreatment with vaspin prevented LA-induced apoptosis in insulin-stimulated endothelial cells; this anti-apoptotic effect of vaspin was also eliminated by pretreatment with Wortmannin. The present study indicates that vaspin protects vascular endothelial cells from FFA-induced apoptosis through upregulation of the PI3-kinase/Akt signaling pathway. Our study is the first to demonstrate that vascular cells can be targets of vaspin. Our results further suggest that vaspin could have beneficial effects on the atherosclerosis.     

Diversity,Distribution, and Host Plant of Endophytic Fungi: A Focus on Korea

Endophytic fungi occupy inner plant tissues, which results in various interactions between the fungus and host. Studies on endophytic fungi have been conducted in Korea for over 30 years. This paper summarizes the published results of those studies. The endophytic fungi of approximately 132 plant species in Korea have been studied since the 1990s, resulting in over 118 publications. The host plants featured in these studies comprised 3 species of mosses, 34 species of woody plants, and 95 species of herbaceous plants. At the family level, the most studied plants were members of the Poaceae family, covering 18 species. Regionally, these studies were conducted throughout Korea, but over half of the studies were conducted in Gyeongsangbuk-do, Gangwon-do, and Chungcheongnam-do. Relatively few studies have been conducted in a metropolis such as Seoul. We confirmed 5 phyla, 16 classes, 49 orders, 135 families, 305 genera, and 855 taxa of endophytic fungi, excluding Incertae sedis, whose relationship with others are unknown. Most of the endophytic fungi belonged to Ascomycota (93.2%), and a few belonged to Basidiomycota (3.6%). Since the diversity of endophytic fungi differs depending on the host plant, plant tissue, and distribution region, future studies should be conducted on multiple host plants and in various regions. Future studies on endophytic fungi are expected to broaden, including genomics and taxonomic and ecological studies of secondary metabolites.     

Cell-specific and temporal aspects of gene expression in the chicken oviduct at different stages of the laying cycle

Egg formation and embryonic development occur as the yolk passes through the magnum, isthmus, and shell gland of the oviduct before oviposition in hens. The present study identified candidate genes associated with secretory function of the chicken oviduct after ovulation and contributing to egg formation and oviposition. Hens (n = 5 per time point) were euthanized to recover the reproductive tract when the egg was in the magnum (3 h after ovulation) and the shell gland (20 h after ovulation). Total RNA was extracted from each segment of the oviducts and subjected to Affymetrix chicken GeneChip analysis. Quantitative PCR and in situ hybridization analyses of selected genes confirmed the validity of the gene expression patterns detected using microarray analysis. In particular, ACP1, CALB1, CYP26A1, PENK, RCAN1 and SPP1 expression increased significantly in the shell gland between 3 h and 20 h postovulation, whereas only RCNA1 expression increased significantly in the magnum between 3 h and 20 h postovulation. Results of the high-throughput analysis revealed cell-specific and temporal changes in gene expression in the oviduct at 3 h and 20 h postovulation in laying hens provide novel insight into changes at the molecular and cellular levels of candidate genes related to formation of the egg and oviposition.     

Formation and isolation of nanocrystal complexes between dextrins and n-butanol

Starch dextrins of different molecular sizes (DP_n 311, 142 and 39) were prepared by hydrolyzing a high amylose maize starch in acidic alcohol solutions. The dextrins were dissolved in an aqueous dimethyl sulfoxide solution (90% DMSO), and then the solution was allowed to migrate down into n-butanol separated by a membrane filter. The complex was gradually formed between the dextrin and butanol, and precipitated in the butanol layer. The dextrin–butanol complex yielded V6-I type crystals with broad reflections (d-spacings 1.123, 0.657 and 0.429 nm) under X-ray diffractograms. Platelets of average length less than 100 nm, interspersed in amorphous matrices, were observed in complexes of DP_n 311 and 142, but that of DP_n 39 showed different morphology, and the formation of complexes was limited. By hydrolyzing the complex of DP_n 311 with α-amylase, amorphous matrices were selectively removed, and crystallites of 23–72 nm showing a V6-I X-ray diffraction pattern were obtained. However, crystallites in complexes of DP_n 142 and 39 were eroded by amylolysis, forming large aggregates.     

Enhanced tolerance to oxidative stress in transgenic tobacco plants expressing three antioxidant enzymes in chloroplasts

The effect of simultaneous expression of genes encoding three antioxidant enzymes, copper zinc superoxide dismutase (CuZnSOD, EC 1.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), and dehydroascorbate (DHA) reductase (DHAR, EC 1.8.5.1), in the chloroplasts of tobacco plants was investigated under oxidative stress conditions. In previous studies, transgenic tobacco plants expressing both CuZnSOD and APX in chloroplast (CA plants), or DHAR in chloroplast showed enhanced tolerance to oxidative stresses, such as paraquat and salt. In this study, in order to develop transgenic plants that were more resistant to oxidative stress, we introduced the gene encoding DHAR into CA transgenic plants. Mature leaves of transgenic plants expressing all three antioxidant genes (CAD plants) had approximately 1.6–2.1 times higher DHAR activity, and higher ratios of reduced ascorbate (AsA) to DHA, and oxidized glutathione (GSSG) to reduced glutathione (GSH) compared to CA plants. CAD plants were more resistant to paraquat-induced stress, exhibiting only 18.1% reduction in membrane damage relative to CA plants. In addition, seedlings of CAD plants had enhanced tolerance to NaCI (100 mM) compared to CA plants. These results indicate that the simultaneous expression of multiple antioxidant enzymes, such as CuZnSOD, APX, and DHAR, in chloroplasts is more effective than single or double expression for developing transgenic plants with enhanced tolerance to multiple environmental stresses.