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
Alpha-hemolysin (HlyA) is an extracellular toxin secreted by Escherichia coli, targeting to plasma membranes of eukaryotic cells. Recently it was found that this toxin is released to external media associated to bacte...Alpha-hemolysin (HlyA) is an extracellular toxin secreted by Escherichia coli, targeting to plasma membranes of eukaryotic cells. Recently it was found that this toxin is released to external media associated to bacterial outer membrane vesicles (OMVs), but the hemolytic mechanism in this way has not been studied yet. Our results report that HlyA is the only protein present in OMVs that is responsible for erythrocyte lysis, and show that no fusion event is involved in the lytic mechanism of OMVs-HlyA. Furthermore, the specific hemolytic activity is approximately 10 fold higher than that of purified free-HlyA, showing the same relative lysis efficiency and specificity for erythrocytes from different species. OMVs could be an important auxiliary way of secretion, acting mainly as a concentration mechanism of HlyA near the target cells. Cell lysis would occur after toxin transfer from OMVs to target membranes, as demonstrated by hemolysis kinetic studies, lipid mixing and western blot assays.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Alpha-hemolysin (HlyA) is an extracellular toxin secreted by Escherichia coli, targeting to plasma membranes of eukaryotic cells. Recently it was found that this toxin is released to external media associated to bacterial outer membrane vesicles (OMVs), but the hemolytic mechanism in this way has not been studied yet. Our results report that HlyA is the only protein present in OMVs that is responsible for erythrocyte lysis, and show that no fusion event is involved in the lytic mechanism of OMVs-HlyA. Furthermore, the specific hemolytic activity is approximately 10 fold higher than that of purified free-HlyA, showing the same relative lysis efficiency and specificity for erythrocytes from different species. OMVs could be an important auxiliary way of secretion, acting mainly as a concentration mechanism of HlyA near the target cells. Cell lysis would occur after toxin transfer from OMVs to target membranes, as demonstrated by hemolysis kinetic studies, lipid mixing and western blot assays.
