The extracellular enzyme activities of sclerotia-forming and nonsclerotia- forming single spore strains of Morchella conica and M. crasspies were determined and compared. The non sclerotia-forming strains of M. conica...The extracellular enzyme activities of sclerotia-forming and nonsclerotia- forming single spore strains of Morchella conica and M. crasspies were determined and compared. The non sclerotia-forming strains of M. conica exhibited higher aver- age activities of protease, catalase and xylanase but lower laccase activity than those of sclerotia-forming strains. However, the differences did not reach significance level. The soluble amylases activity of M. crasspies was significantly higher than that of M. conica, while the mean activity of other enzymes had differences between them, but the differences did not reach significance level.展开更多
The companion fungus ( Grifola sp.) related to sclerotial formation from hyphae of Grifola umbellata (Pers.) Pilat was isolated from the cavity associated with sclerotia of G. umbellata in natural condition. Experimen...The companion fungus ( Grifola sp.) related to sclerotial formation from hyphae of Grifola umbellata (Pers.) Pilat was isolated from the cavity associated with sclerotia of G. umbellata in natural condition. Experimental results showed that the pure culture of G. umbellata was unable to form sclerotia, whereas sclerotia produced easily in flasks or on trunks when the companion fungus was inoculated together with strain of G. umbellata. The companion fungus is critical for sclerotium formation from hyphae of G. umbellata. Morphological differences were found in cultures of the two fungi. The companion fungus possesses thin-walled narrow hyphae, while G. umbellata is of wider hyphae which are either thick- or thin-walled.展开更多
We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ...We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ability to form sclerotia on different growth media. PCR analysis was done on the isolates to detect 2 structural genes, aflD and aflQ, involved in aflatoxin biosynthesis pathway. Positive A. flavus isolates for one or both genes were grown on Yeast Extract Sucrose Agar medium and aflatoxins quantified using LCMSMS. All the isolates formed large sclerotia and their formation was influenced by media type but could not be related to amount of aflatoxins produced both in vivo and in vitro. Though sclerotia are perennating structures and so contribute to survival index of a fungus, their initiation is regulated by external factors though ability to form is genetic. This brings ambiguity of their presence or abundance as a measure of toxicity.展开更多
基金Supported by China Agriculture Research System(CARS24)National High Technology Research and Development Program of China(863 Program,2007AA021506)~~
文摘The extracellular enzyme activities of sclerotia-forming and nonsclerotia- forming single spore strains of Morchella conica and M. crasspies were determined and compared. The non sclerotia-forming strains of M. conica exhibited higher aver- age activities of protease, catalase and xylanase but lower laccase activity than those of sclerotia-forming strains. However, the differences did not reach significance level. The soluble amylases activity of M. crasspies was significantly higher than that of M. conica, while the mean activity of other enzymes had differences between them, but the differences did not reach significance level.
文摘The companion fungus ( Grifola sp.) related to sclerotial formation from hyphae of Grifola umbellata (Pers.) Pilat was isolated from the cavity associated with sclerotia of G. umbellata in natural condition. Experimental results showed that the pure culture of G. umbellata was unable to form sclerotia, whereas sclerotia produced easily in flasks or on trunks when the companion fungus was inoculated together with strain of G. umbellata. The companion fungus is critical for sclerotium formation from hyphae of G. umbellata. Morphological differences were found in cultures of the two fungi. The companion fungus possesses thin-walled narrow hyphae, while G. umbellata is of wider hyphae which are either thick- or thin-walled.
文摘We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ability to form sclerotia on different growth media. PCR analysis was done on the isolates to detect 2 structural genes, aflD and aflQ, involved in aflatoxin biosynthesis pathway. Positive A. flavus isolates for one or both genes were grown on Yeast Extract Sucrose Agar medium and aflatoxins quantified using LCMSMS. All the isolates formed large sclerotia and their formation was influenced by media type but could not be related to amount of aflatoxins produced both in vivo and in vitro. Though sclerotia are perennating structures and so contribute to survival index of a fungus, their initiation is regulated by external factors though ability to form is genetic. This brings ambiguity of their presence or abundance as a measure of toxicity.
