Identification and evaluation of potential bio-control fungal endophytes against <Emphasis Type="Italic">Ustilagonoidea virens</Emphasis> on rice plants

False smut disease of rice is posing an increasing concern for production, not only because of the hiking epidemic occurrence in rice production, but also because of the challenging specific pathogenesis of the disease. The aim of this work was to evaluate the potential of five fungal endophytes to reduce negative effects of rice false smut fungus (Ustilagonoidea virens) on rice plants, in both the laboratory and greenhouse. Though all the fungal isolates showed the ability to inhibit the growth of U. virens with varying degrees, isolate E337 showed significant antagonistic activity against the pathogenic fungi. The isolate E337 was identified as Antennariella placitae by molecular and morphological data analysis including 18S rDNA sequence analysis. This isolate showed a significant in vitro inhibition of mycelial growth of U. virens by dual culture method and it was subsequently tested for its in vivo biocontrol potential on false smut disease on rice plants. Greenhouse experiments confirmed that applications of conidia of A. placitae protected rice plants by improving rice yield and by decreasing the severity of false smut disease on susceptible rice plants. This is the first report where A. placitae has been identified as a biocontrol organism.     

G(1)-phase specific apoptosis in liver carcinoma cell line induced by copper-1,10-phenanthroline

Reactive oxygen species play an important role in the mediation of cell killing. But the mechanistic links between reactive oxygen species (ROS) and cell death remains unclear. There was a speculation that ROS, especially hydroxyl radicals can induce necrosis but not apoptosis in cells treated with copper-1,10-phenanthroline, IICu(OP)(2). In this paper, liver carcinoma cell line (Bel-7402) was treated with IICu(OP)(2) and its effect was examined by several means. Cells were found to undergo changes characteristic of apoptosis. Hoechst staining showed apoptotic body appeared in the cells induced by IICu(OP)(2). When DNA extracted from the cells treated with IICu(OP)(2) was analyzed by agarose gel electrophoresis it generated 'ladder' pattern of discontinuous DNA fragments. Sub-G(1) peak was detected in treated cells. Furthermore, two different flow cytometric methods were used, each allowing us to relate the apoptotic cells to the position the cell-cycle position. Apoptosis induced by IICu(OP)(2) was limited to G(1)-phase cells. Using cyclin analysis, the expression of cyclin E in G(1) was blocked. Thus, it was concluded that IICu(OP)(2) can induce G(1)-phase specific apoptosis in Bel-7402.