Altemaria alternata were isolated from wheat seeds collected from villages in Tianshui area of Gansu Province where Kaschin-Beck disease is prevalent. TLC, IR and UV analyses of metabolic extract of A. alternata show ...Altemaria alternata were isolated from wheat seeds collected from villages in Tianshui area of Gansu Province where Kaschin-Beck disease is prevalent. TLC, IR and UV analyses of metabolic extract of A. alternata show that A. alternata produce main secondary metabolites, including alternariol, alternariol methyl ether, and tenuazonic acid.There was a significant decrease in Se-GSH-Px and SOD activities, and an acceleration in lipid peroxidation in rats fed with a diet containing metabolites produced by A. alternata.展开更多
[Objective] This study aimed to uncover the biological characteristics of a parasitical fungus in Chrysosp/enium absconditicapsu/um J. T. Pan leaves. [Method] PDA medium was used to isolate the fungus from C. abscondi...[Objective] This study aimed to uncover the biological characteristics of a parasitical fungus in Chrysosp/enium absconditicapsu/um J. T. Pan leaves. [Method] PDA medium was used to isolate the fungus from C. absconditicapsulum leaves; PDA medium, modified KB medium and Czapek medium were adopted to cultivate the isolated strain. [Result] Colonies of the strain were stretched, white, fedora- shaped with smooth and wavy edges, and showed diameter growth on PDA medi- um, modified KB medium and Czapek medium. At the late stage of culture, the colonies turned into cyanish brown on the above media. Spores were black and born on the surface of colonies on PDA medium with blackened medium. While on modified KB medium and Czapek medium, they were born at the edge of colonies with blackened medium. The spores varied in a wide range of shapes, mostly ob- clavate, sometimes spherical or ellipsoidal. The conidia were muriformly septate with transverse or longitudinal or oblique septations. The pseudo-beaks were short and cylindrical. [Conclusion] According to relevant literatures, the isolated strain is a fungus in Alternaria, Dematiaceae, Hylohomycetales, Hyphomycetes, Deuteromycotina.展开更多
The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high lev...The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high levels of antagonistic properties, They significantly reduced brown spot in detached tobacco leaves when artificially inoculated with Alternaria alternata. Culture filtrate of the most effective bacterial isolate which designated as Tpb88 was shown to be very efficient in inhibiting mycelial growth of A alternata in dual cultures. Culture filtrate of Tpb88 inhibited germination and germ tube elongation of A alternata. The results showed that the culture filtrate directly inhibited spore germination of A alternata, especially during the first hours of the paired cultivation. The rate of antagonistic activity of culture filtrate of Tpb88 depended on its concentration in the mixture. The greatest inhibition of spore germination was ob served at the highest concentration of filtrate （filtrate to fungal spores inocula mixed in proportion 1 ： 50）. These suggest that the hypothetic mechanism of Tpb88 against tobacco brown spot is to produce antagonistic substances.展开更多
文摘Altemaria alternata were isolated from wheat seeds collected from villages in Tianshui area of Gansu Province where Kaschin-Beck disease is prevalent. TLC, IR and UV analyses of metabolic extract of A. alternata show that A. alternata produce main secondary metabolites, including alternariol, alternariol methyl ether, and tenuazonic acid.There was a significant decrease in Se-GSH-Px and SOD activities, and an acceleration in lipid peroxidation in rats fed with a diet containing metabolites produced by A. alternata.
文摘[Objective] This study aimed to uncover the biological characteristics of a parasitical fungus in Chrysosp/enium absconditicapsu/um J. T. Pan leaves. [Method] PDA medium was used to isolate the fungus from C. absconditicapsulum leaves; PDA medium, modified KB medium and Czapek medium were adopted to cultivate the isolated strain. [Result] Colonies of the strain were stretched, white, fedora- shaped with smooth and wavy edges, and showed diameter growth on PDA medi- um, modified KB medium and Czapek medium. At the late stage of culture, the colonies turned into cyanish brown on the above media. Spores were black and born on the surface of colonies on PDA medium with blackened medium. While on modified KB medium and Czapek medium, they were born at the edge of colonies with blackened medium. The spores varied in a wide range of shapes, mostly ob- clavate, sometimes spherical or ellipsoidal. The conidia were muriformly septate with transverse or longitudinal or oblique septations. The pseudo-beaks were short and cylindrical. [Conclusion] According to relevant literatures, the isolated strain is a fungus in Alternaria, Dematiaceae, Hylohomycetales, Hyphomycetes, Deuteromycotina.
基金State Tobacco Monopoly Administration of China (110200201008)
文摘The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high levels of antagonistic properties, They significantly reduced brown spot in detached tobacco leaves when artificially inoculated with Alternaria alternata. Culture filtrate of the most effective bacterial isolate which designated as Tpb88 was shown to be very efficient in inhibiting mycelial growth of A alternata in dual cultures. Culture filtrate of Tpb88 inhibited germination and germ tube elongation of A alternata. The results showed that the culture filtrate directly inhibited spore germination of A alternata, especially during the first hours of the paired cultivation. The rate of antagonistic activity of culture filtrate of Tpb88 depended on its concentration in the mixture. The greatest inhibition of spore germination was ob served at the highest concentration of filtrate （filtrate to fungal spores inocula mixed in proportion 1 ： 50）. These suggest that the hypothetic mechanism of Tpb88 against tobacco brown spot is to produce antagonistic substances.
