Magdi El-Sayed | Aswan University (original) (raw)

Papers by Magdi El-Sayed

Journal of General Plant Pathology, 2009

Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (... more Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (Egyptian henbane) grown in a greenhouse at Yamaguchi city, Japan, in the summer of 2008. Nucleotide sequence analysis of rDNA-ITS and 28S rDNA supported the morphological identification of the isolate, which caused the same disease symptoms after reinoculation of the host. This new disease was named “Cladosporium leaf spot of Egyptian henbane”.

Journal of General Plant Pathology, 2010

The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the dese... more The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the desert plant Hyoscyamus muticus, against two rice pathogens, Magnaporthe oryzae and Rhizoctonia solani, were studied. The minimum inhibitory concentration of hyoscyamine that resulted in distinctive inhibition (MIC50) was 1 μg/ml for both fungi. Exposure to hyoscyamine caused the leakage of electrolytes from the mycelia of both fungi. Hyoscyamine (>1 μg/ml) irreversibly delayed or inhibited conidial germination and appressorium formation in M. oryzae grown on polystyrene plates. Hyoscyamine effectively inhibited the attachment of conidia to the surface of rice (Oryza sativa) leaves and inhibited appressorium formation on the leaves. A high concentration of scopolamine (1000 μg/ml) also delayed or inhibited conidial germination in M. oryzae, but conidial germination was restored after washing the conidia with water. Antifungal activity of hyoscyamine was reduced by scopolamine. Magnaporthe oryzae infection was significantly suppressed (by >95%) in leaves of intact rice plants treated with hyoscyamine (10 μg/ml). Moreover, 10 μg hyoscyamine/ml significantly reduced the disease severity index for sheath blight to ≤0.2, when compared with the disease index of control plants (>7.0). Hyoscyamine (>20 μg/ml) completely inhibited sclerotial germination and development of R. solani by delaying the initiation, maturation, and melanization of the sclerotia. These results suggest that tropane alkaloids may be useful for controlling blast and sheath blight diseases of rice and for studying the mechanisms that regulate conidial germination in M. oryzae and sclerotial germination and development in R. solani.

Febs Letters, 2007

The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membra... more The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membranes followed by leakage of cell components. However, details of the modes of action of the compound on fungal cells are poorly understood. In the present study, mechanisms involved in a-tomatine-induced cell death of fungi were examined using a filamentous pathogenic fungus Fusarium oxysporum. a-Tomatine-induced cell death of F. oxysporum (TICDF) occurred only under aerobic conditions and was blocked by the mitochondrial F 0 F 1 -ATPase inhibitor oligomycin, the caspase inhibitor D-VAD-fmk, and protein synthesis inhibitor cycloheximide. Fungal cells exposed to a-tomatine showed TUNEL-positive nuclei, depolarization of transmembrane potential of mitochondria, and reactive oxygen species (ROS) accumulation. These results suggest that TICDF occurs through a programmed cell death process in which mitochondria play a pivotal role. Pharmacological studies using inhibitors suggest that a-tomatine activates phosphotyrosine kinase and monomeric G-protein signaling pathways leading to Ca 2+ elevation and ROS burst in F. oxysporum cells.

Folia Microbiologica, 2009

Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautograp... more Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautography against fungi associated with H. muticus grown in Egypt, and those isolated from other plants grown in Japan. All 40 fungal strains were tolerant to Sco and sensitive to Hcy, exhibiting a growth inhibition zone around the Hcy spot on the bioautography plate. The strains were grouped into three types based on the appearance of the inhibition zone: (i) 17 strains exhibiting a clear inhibition zone, which remained clear at 8 d after incubation (type I); (ii) 22 strains exhibiting the inhibition zone with a brown circle surrounding the zone and regrowth within the inhibition zone (type II); (iii) 1 strain exhibiting the inhibition zone with no brown circle and regrowth within the inhibition zone (type III). In the type II and III strains, Hcy disappeared, and other alkaloids were found in the inhibition zones in its place. Hcy feeding experiments using Penicillium purpurogenum (type II) and Cunninghamella elegans (type III) revealed that these fungi may convert Hcy to a new alkaloid compound.

Asian Journal of Plant Sciences, 2009

Journal of General Plant Pathology, 2009

Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (... more Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (Egyptian henbane) grown in a greenhouse at Yamaguchi city, Japan, in the summer of 2008. Nucleotide sequence analysis of rDNA-ITS and 28S rDNA supported the morphological identification of the isolate, which caused the same disease symptoms after reinoculation of the host. This new disease was named “Cladosporium leaf spot of Egyptian henbane”.

Journal of General Plant Pathology, 2010

The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the dese... more The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the desert plant Hyoscyamus muticus, against two rice pathogens, Magnaporthe oryzae and Rhizoctonia solani, were studied. The minimum inhibitory concentration of hyoscyamine that resulted in distinctive inhibition (MIC50) was 1 μg/ml for both fungi. Exposure to hyoscyamine caused the leakage of electrolytes from the mycelia of both fungi. Hyoscyamine (>1 μg/ml) irreversibly delayed or inhibited conidial germination and appressorium formation in M. oryzae grown on polystyrene plates. Hyoscyamine effectively inhibited the attachment of conidia to the surface of rice (Oryza sativa) leaves and inhibited appressorium formation on the leaves. A high concentration of scopolamine (1000 μg/ml) also delayed or inhibited conidial germination in M. oryzae, but conidial germination was restored after washing the conidia with water. Antifungal activity of hyoscyamine was reduced by scopolamine. Magnaporthe oryzae infection was significantly suppressed (by >95%) in leaves of intact rice plants treated with hyoscyamine (10 μg/ml). Moreover, 10 μg hyoscyamine/ml significantly reduced the disease severity index for sheath blight to ≤0.2, when compared with the disease index of control plants (>7.0). Hyoscyamine (>20 μg/ml) completely inhibited sclerotial germination and development of R. solani by delaying the initiation, maturation, and melanization of the sclerotia. These results suggest that tropane alkaloids may be useful for controlling blast and sheath blight diseases of rice and for studying the mechanisms that regulate conidial germination in M. oryzae and sclerotial germination and development in R. solani.

Journal of General Plant Pathology, 2010

Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse... more Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse in Yamaguchi city, Japan, in the late summer of 2008 and 2009. The symptoms were identical to those of rots caused by Choanephora species. The pathogen was isolated and identified as C. cucurbitarum (Berkeley and Ravenel) Thaxter. This new disease was named Choanephora rot (Kougai-kabi-byo) of Egyptian henbane.

Febs Letters, 2007

The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membra... more The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membranes followed by leakage of cell components. However, details of the modes of action of the compound on fungal cells are poorly understood. In the present study, mechanisms involved in a-tomatine-induced cell death of fungi were examined using a filamentous pathogenic fungus Fusarium oxysporum. a-Tomatine-induced cell death of F. oxysporum (TICDF) occurred only under aerobic conditions and was blocked by the mitochondrial F 0 F 1 -ATPase inhibitor oligomycin, the caspase inhibitor D-VAD-fmk, and protein synthesis inhibitor cycloheximide. Fungal cells exposed to a-tomatine showed TUNEL-positive nuclei, depolarization of transmembrane potential of mitochondria, and reactive oxygen species (ROS) accumulation. These results suggest that TICDF occurs through a programmed cell death process in which mitochondria play a pivotal role. Pharmacological studies using inhibitors suggest that a-tomatine activates phosphotyrosine kinase and monomeric G-protein signaling pathways leading to Ca 2+ elevation and ROS burst in F. oxysporum cells.

Journal of General Plant Pathology, 2009

Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (... more Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (Egyptian henbane) grown in a greenhouse at Yamaguchi city, Japan, in the summer of 2008. Nucleotide sequence analysis of rDNA-ITS and 28S rDNA supported the morphological identification of the isolate, which caused the same disease symptoms after reinoculation of the host. This new disease was named “Cladosporium leaf spot of Egyptian henbane”.

Folia Microbiologica, 2009

Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautograp... more Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautography against fungi associated with H. muticus grown in Egypt, and those isolated from other plants grown in Japan. All 40 fungal strains were tolerant to Sco and sensitive to Hcy, exhibiting a growth inhibition zone around the Hcy spot on the bioautography plate. The strains were grouped into three types based on the appearance of the inhibition zone: (i) 17 strains exhibiting a clear inhibition zone, which remained clear at 8 d after incubation (type I); (ii) 22 strains exhibiting the inhibition zone with a brown circle surrounding the zone and regrowth within the inhibition zone (type II); (iii) 1 strain exhibiting the inhibition zone with no brown circle and regrowth within the inhibition zone (type III). In the type II and III strains, Hcy disappeared, and other alkaloids were found in the inhibition zones in its place. Hcy feeding experiments using Penicillium purpurogenum (type II) and Cunninghamella elegans (type III) revealed that these fungi may convert Hcy to a new alkaloid compound.

Journal of General Plant Pathology, 2010

The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the dese... more The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the desert plant Hyoscyamus muticus, against two rice pathogens, Magnaporthe oryzae and Rhizoctonia solani, were studied. The minimum inhibitory concentration of hyoscyamine that resulted in distinctive inhibition (MIC50) was 1 μg/ml for both fungi. Exposure to hyoscyamine caused the leakage of electrolytes from the mycelia of both fungi. Hyoscyamine (>1 μg/ml) irreversibly delayed or inhibited conidial germination and appressorium formation in M. oryzae grown on polystyrene plates. Hyoscyamine effectively inhibited the attachment of conidia to the surface of rice (Oryza sativa) leaves and inhibited appressorium formation on the leaves. A high concentration of scopolamine (1000 μg/ml) also delayed or inhibited conidial germination in M. oryzae, but conidial germination was restored after washing the conidia with water. Antifungal activity of hyoscyamine was reduced by scopolamine. Magnaporthe oryzae infection was significantly suppressed (by >95%) in leaves of intact rice plants treated with hyoscyamine (10 μg/ml). Moreover, 10 μg hyoscyamine/ml significantly reduced the disease severity index for sheath blight to ≤0.2, when compared with the disease index of control plants (>7.0). Hyoscyamine (>20 μg/ml) completely inhibited sclerotial germination and development of R. solani by delaying the initiation, maturation, and melanization of the sclerotia. These results suggest that tropane alkaloids may be useful for controlling blast and sheath blight diseases of rice and for studying the mechanisms that regulate conidial germination in M. oryzae and sclerotial germination and development in R. solani.

Asian Journal of Plant Sciences, 2009

Febs Letters, 2007

The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membra... more The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membranes followed by leakage of cell components. However, details of the modes of action of the compound on fungal cells are poorly understood. In the present study, mechanisms involved in a-tomatine-induced cell death of fungi were examined using a filamentous pathogenic fungus Fusarium oxysporum. a-Tomatine-induced cell death of F. oxysporum (TICDF) occurred only under aerobic conditions and was blocked by the mitochondrial F 0 F 1 -ATPase inhibitor oligomycin, the caspase inhibitor D-VAD-fmk, and protein synthesis inhibitor cycloheximide. Fungal cells exposed to a-tomatine showed TUNEL-positive nuclei, depolarization of transmembrane potential of mitochondria, and reactive oxygen species (ROS) accumulation. These results suggest that TICDF occurs through a programmed cell death process in which mitochondria play a pivotal role. Pharmacological studies using inhibitors suggest that a-tomatine activates phosphotyrosine kinase and monomeric G-protein signaling pathways leading to Ca 2+ elevation and ROS burst in F. oxysporum cells.

Folia Microbiologica, 2009

Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautograp... more Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautography against fungi associated with H. muticus grown in Egypt, and those isolated from other plants grown in Japan. All 40 fungal strains were tolerant to Sco and sensitive to Hcy, exhibiting a growth inhibition zone around the Hcy spot on the bioautography plate. The strains were grouped into three types based on the appearance of the inhibition zone: (i) 17 strains exhibiting a clear inhibition zone, which remained clear at 8 d after incubation (type I); (ii) 22 strains exhibiting the inhibition zone with a brown circle surrounding the zone and regrowth within the inhibition zone (type II); (iii) 1 strain exhibiting the inhibition zone with no brown circle and regrowth within the inhibition zone (type III). In the type II and III strains, Hcy disappeared, and other alkaloids were found in the inhibition zones in its place. Hcy feeding experiments using Penicillium purpurogenum (type II) and Cunninghamella elegans (type III) revealed that these fungi may convert Hcy to a new alkaloid compound.

Journal of General Plant Pathology, 2010

Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse... more Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse in Yamaguchi city, Japan, in the late summer of 2008 and 2009. The symptoms were identical to those of rots caused by Choanephora species. The pathogen was isolated and identified as C. cucurbitarum (Berkeley and Ravenel) Thaxter. This new disease was named Choanephora rot (Kougai-kabi-byo) of Egyptian henbane.

Asian Journal of Plant Sciences, 2009

Journal of General Plant Pathology, 2010

Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse... more Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse in Yamaguchi city, Japan, in the late summer of 2008 and 2009. The symptoms were identical to those of rots caused by Choanephora species. The pathogen was isolated and identified as C. cucurbitarum (Berkeley and Ravenel) Thaxter. This new disease was named Choanephora rot (Kougai-kabi-byo) of Egyptian henbane.

European Journal of Chemistry, 2010

KEYWORDS Ageratum conyzoides L., is an annual herb with a long history of traditional medicinal u... more KEYWORDS Ageratum conyzoides L., is an annual herb with a long history of traditional medicinal uses in many countries in the world, especially in the tropical and subtropical regions. A wide range of chemical compounds including alkaloids, flavonoids, chromenes, benzofurans and terpenoids have been isolated from this species. Extracts and metabolites from this plant have been found to possess pharmacological and insecticidal activities. In continuation of our interest in the Egyptian medicinal plants, the reinvestigation of the methylenechloride extract of the air-dried aerial parts of Ageratum conyzoides afforded a new natural compound 1, pyrrolone, 5-ethoxy-1H-pyrrol-2(5H)-one, together with a known flavonoid. The structures of the compounds were determined by comprehensive NMR studies, including DEPT, COSY, HMQC, HMBC, and MS.

Biotechnology Letters, 2004

Feeding stemmadenine to Catharanthus roseuscell suspension culture resulted in the accumulation o... more Feeding stemmadenine to Catharanthus roseuscell suspension culture resulted in the accumulation of catharanthine, tabersonine and condylocarpine. Condylocarpine is not an intermediate in the pathway to catharanthine or tabersonine when it is fed to the cultures. The results support the hypothesis that stemmadenine is an intermediate in the pathway to catharanthine and tabersonine.

Journal of General Plant Pathology, 2009

Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (... more Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (Egyptian henbane) grown in a greenhouse at Yamaguchi city, Japan, in the summer of 2008. Nucleotide sequence analysis of rDNA-ITS and 28S rDNA supported the morphological identification of the isolate, which caused the same disease symptoms after reinoculation of the host. This new disease was named “Cladosporium leaf spot of Egyptian henbane”.

Journal of General Plant Pathology, 2010

The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the dese... more The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the desert plant Hyoscyamus muticus, against two rice pathogens, Magnaporthe oryzae and Rhizoctonia solani, were studied. The minimum inhibitory concentration of hyoscyamine that resulted in distinctive inhibition (MIC50) was 1 μg/ml for both fungi. Exposure to hyoscyamine caused the leakage of electrolytes from the mycelia of both fungi. Hyoscyamine (>1 μg/ml) irreversibly delayed or inhibited conidial germination and appressorium formation in M. oryzae grown on polystyrene plates. Hyoscyamine effectively inhibited the attachment of conidia to the surface of rice (Oryza sativa) leaves and inhibited appressorium formation on the leaves. A high concentration of scopolamine (1000 μg/ml) also delayed or inhibited conidial germination in M. oryzae, but conidial germination was restored after washing the conidia with water. Antifungal activity of hyoscyamine was reduced by scopolamine. Magnaporthe oryzae infection was significantly suppressed (by >95%) in leaves of intact rice plants treated with hyoscyamine (10 μg/ml). Moreover, 10 μg hyoscyamine/ml significantly reduced the disease severity index for sheath blight to ≤0.2, when compared with the disease index of control plants (>7.0). Hyoscyamine (>20 μg/ml) completely inhibited sclerotial germination and development of R. solani by delaying the initiation, maturation, and melanization of the sclerotia. These results suggest that tropane alkaloids may be useful for controlling blast and sheath blight diseases of rice and for studying the mechanisms that regulate conidial germination in M. oryzae and sclerotial germination and development in R. solani.

Febs Letters, 2007

The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membra... more The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membranes followed by leakage of cell components. However, details of the modes of action of the compound on fungal cells are poorly understood. In the present study, mechanisms involved in a-tomatine-induced cell death of fungi were examined using a filamentous pathogenic fungus Fusarium oxysporum. a-Tomatine-induced cell death of F. oxysporum (TICDF) occurred only under aerobic conditions and was blocked by the mitochondrial F 0 F 1 -ATPase inhibitor oligomycin, the caspase inhibitor D-VAD-fmk, and protein synthesis inhibitor cycloheximide. Fungal cells exposed to a-tomatine showed TUNEL-positive nuclei, depolarization of transmembrane potential of mitochondria, and reactive oxygen species (ROS) accumulation. These results suggest that TICDF occurs through a programmed cell death process in which mitochondria play a pivotal role. Pharmacological studies using inhibitors suggest that a-tomatine activates phosphotyrosine kinase and monomeric G-protein signaling pathways leading to Ca 2+ elevation and ROS burst in F. oxysporum cells.

Folia Microbiologica, 2009

Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautograp... more Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautography against fungi associated with H. muticus grown in Egypt, and those isolated from other plants grown in Japan. All 40 fungal strains were tolerant to Sco and sensitive to Hcy, exhibiting a growth inhibition zone around the Hcy spot on the bioautography plate. The strains were grouped into three types based on the appearance of the inhibition zone: (i) 17 strains exhibiting a clear inhibition zone, which remained clear at 8 d after incubation (type I); (ii) 22 strains exhibiting the inhibition zone with a brown circle surrounding the zone and regrowth within the inhibition zone (type II); (iii) 1 strain exhibiting the inhibition zone with no brown circle and regrowth within the inhibition zone (type III). In the type II and III strains, Hcy disappeared, and other alkaloids were found in the inhibition zones in its place. Hcy feeding experiments using Penicillium purpurogenum (type II) and Cunninghamella elegans (type III) revealed that these fungi may convert Hcy to a new alkaloid compound.

Asian Journal of Plant Sciences, 2009

Journal of General Plant Pathology, 2009

Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (... more Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (Egyptian henbane) grown in a greenhouse at Yamaguchi city, Japan, in the summer of 2008. Nucleotide sequence analysis of rDNA-ITS and 28S rDNA supported the morphological identification of the isolate, which caused the same disease symptoms after reinoculation of the host. This new disease was named “Cladosporium leaf spot of Egyptian henbane”.

Journal of General Plant Pathology, 2010

The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the dese... more The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the desert plant Hyoscyamus muticus, against two rice pathogens, Magnaporthe oryzae and Rhizoctonia solani, were studied. The minimum inhibitory concentration of hyoscyamine that resulted in distinctive inhibition (MIC50) was 1 μg/ml for both fungi. Exposure to hyoscyamine caused the leakage of electrolytes from the mycelia of both fungi. Hyoscyamine (>1 μg/ml) irreversibly delayed or inhibited conidial germination and appressorium formation in M. oryzae grown on polystyrene plates. Hyoscyamine effectively inhibited the attachment of conidia to the surface of rice (Oryza sativa) leaves and inhibited appressorium formation on the leaves. A high concentration of scopolamine (1000 μg/ml) also delayed or inhibited conidial germination in M. oryzae, but conidial germination was restored after washing the conidia with water. Antifungal activity of hyoscyamine was reduced by scopolamine. Magnaporthe oryzae infection was significantly suppressed (by >95%) in leaves of intact rice plants treated with hyoscyamine (10 μg/ml). Moreover, 10 μg hyoscyamine/ml significantly reduced the disease severity index for sheath blight to ≤0.2, when compared with the disease index of control plants (>7.0). Hyoscyamine (>20 μg/ml) completely inhibited sclerotial germination and development of R. solani by delaying the initiation, maturation, and melanization of the sclerotia. These results suggest that tropane alkaloids may be useful for controlling blast and sheath blight diseases of rice and for studying the mechanisms that regulate conidial germination in M. oryzae and sclerotial germination and development in R. solani.

Journal of General Plant Pathology, 2010

Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse... more Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse in Yamaguchi city, Japan, in the late summer of 2008 and 2009. The symptoms were identical to those of rots caused by Choanephora species. The pathogen was isolated and identified as C. cucurbitarum (Berkeley and Ravenel) Thaxter. This new disease was named Choanephora rot (Kougai-kabi-byo) of Egyptian henbane.

Febs Letters, 2007

The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membra... more The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membranes followed by leakage of cell components. However, details of the modes of action of the compound on fungal cells are poorly understood. In the present study, mechanisms involved in a-tomatine-induced cell death of fungi were examined using a filamentous pathogenic fungus Fusarium oxysporum. a-Tomatine-induced cell death of F. oxysporum (TICDF) occurred only under aerobic conditions and was blocked by the mitochondrial F 0 F 1 -ATPase inhibitor oligomycin, the caspase inhibitor D-VAD-fmk, and protein synthesis inhibitor cycloheximide. Fungal cells exposed to a-tomatine showed TUNEL-positive nuclei, depolarization of transmembrane potential of mitochondria, and reactive oxygen species (ROS) accumulation. These results suggest that TICDF occurs through a programmed cell death process in which mitochondria play a pivotal role. Pharmacological studies using inhibitors suggest that a-tomatine activates phosphotyrosine kinase and monomeric G-protein signaling pathways leading to Ca 2+ elevation and ROS burst in F. oxysporum cells.

Journal of General Plant Pathology, 2009

Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (... more Severe brown spots caused by Cladosporium herbarum appeared on the leaves of Hyoscyamus muticus (Egyptian henbane) grown in a greenhouse at Yamaguchi city, Japan, in the summer of 2008. Nucleotide sequence analysis of rDNA-ITS and 28S rDNA supported the morphological identification of the isolate, which caused the same disease symptoms after reinoculation of the host. This new disease was named “Cladosporium leaf spot of Egyptian henbane”.

Folia Microbiologica, 2009

Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautograp... more Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautography against fungi associated with H. muticus grown in Egypt, and those isolated from other plants grown in Japan. All 40 fungal strains were tolerant to Sco and sensitive to Hcy, exhibiting a growth inhibition zone around the Hcy spot on the bioautography plate. The strains were grouped into three types based on the appearance of the inhibition zone: (i) 17 strains exhibiting a clear inhibition zone, which remained clear at 8 d after incubation (type I); (ii) 22 strains exhibiting the inhibition zone with a brown circle surrounding the zone and regrowth within the inhibition zone (type II); (iii) 1 strain exhibiting the inhibition zone with no brown circle and regrowth within the inhibition zone (type III). In the type II and III strains, Hcy disappeared, and other alkaloids were found in the inhibition zones in its place. Hcy feeding experiments using Penicillium purpurogenum (type II) and Cunninghamella elegans (type III) revealed that these fungi may convert Hcy to a new alkaloid compound.

Journal of General Plant Pathology, 2010

The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the dese... more The antifungal activities of hyoscyamine and scopolamine, major alkaloids extracted from the desert plant Hyoscyamus muticus, against two rice pathogens, Magnaporthe oryzae and Rhizoctonia solani, were studied. The minimum inhibitory concentration of hyoscyamine that resulted in distinctive inhibition (MIC50) was 1 μg/ml for both fungi. Exposure to hyoscyamine caused the leakage of electrolytes from the mycelia of both fungi. Hyoscyamine (>1 μg/ml) irreversibly delayed or inhibited conidial germination and appressorium formation in M. oryzae grown on polystyrene plates. Hyoscyamine effectively inhibited the attachment of conidia to the surface of rice (Oryza sativa) leaves and inhibited appressorium formation on the leaves. A high concentration of scopolamine (1000 μg/ml) also delayed or inhibited conidial germination in M. oryzae, but conidial germination was restored after washing the conidia with water. Antifungal activity of hyoscyamine was reduced by scopolamine. Magnaporthe oryzae infection was significantly suppressed (by >95%) in leaves of intact rice plants treated with hyoscyamine (10 μg/ml). Moreover, 10 μg hyoscyamine/ml significantly reduced the disease severity index for sheath blight to ≤0.2, when compared with the disease index of control plants (>7.0). Hyoscyamine (>20 μg/ml) completely inhibited sclerotial germination and development of R. solani by delaying the initiation, maturation, and melanization of the sclerotia. These results suggest that tropane alkaloids may be useful for controlling blast and sheath blight diseases of rice and for studying the mechanisms that regulate conidial germination in M. oryzae and sclerotial germination and development in R. solani.

Asian Journal of Plant Sciences, 2009

Febs Letters, 2007

The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membra... more The tomato saponin a-tomatine has been proposed to kill sensitive cells by binding to cell membranes followed by leakage of cell components. However, details of the modes of action of the compound on fungal cells are poorly understood. In the present study, mechanisms involved in a-tomatine-induced cell death of fungi were examined using a filamentous pathogenic fungus Fusarium oxysporum. a-Tomatine-induced cell death of F. oxysporum (TICDF) occurred only under aerobic conditions and was blocked by the mitochondrial F 0 F 1 -ATPase inhibitor oligomycin, the caspase inhibitor D-VAD-fmk, and protein synthesis inhibitor cycloheximide. Fungal cells exposed to a-tomatine showed TUNEL-positive nuclei, depolarization of transmembrane potential of mitochondria, and reactive oxygen species (ROS) accumulation. These results suggest that TICDF occurs through a programmed cell death process in which mitochondria play a pivotal role. Pharmacological studies using inhibitors suggest that a-tomatine activates phosphotyrosine kinase and monomeric G-protein signaling pathways leading to Ca 2+ elevation and ROS burst in F. oxysporum cells.

Folia Microbiologica, 2009

Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautograp... more Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautography against fungi associated with H. muticus grown in Egypt, and those isolated from other plants grown in Japan. All 40 fungal strains were tolerant to Sco and sensitive to Hcy, exhibiting a growth inhibition zone around the Hcy spot on the bioautography plate. The strains were grouped into three types based on the appearance of the inhibition zone: (i) 17 strains exhibiting a clear inhibition zone, which remained clear at 8 d after incubation (type I); (ii) 22 strains exhibiting the inhibition zone with a brown circle surrounding the zone and regrowth within the inhibition zone (type II); (iii) 1 strain exhibiting the inhibition zone with no brown circle and regrowth within the inhibition zone (type III). In the type II and III strains, Hcy disappeared, and other alkaloids were found in the inhibition zones in its place. Hcy feeding experiments using Penicillium purpurogenum (type II) and Cunninghamella elegans (type III) revealed that these fungi may convert Hcy to a new alkaloid compound.

Journal of General Plant Pathology, 2010

Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse... more Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse in Yamaguchi city, Japan, in the late summer of 2008 and 2009. The symptoms were identical to those of rots caused by Choanephora species. The pathogen was isolated and identified as C. cucurbitarum (Berkeley and Ravenel) Thaxter. This new disease was named Choanephora rot (Kougai-kabi-byo) of Egyptian henbane.

Asian Journal of Plant Sciences, 2009

Journal of General Plant Pathology, 2010

Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse... more Floral rot of Egyptian henbane (Hyoscyamus muticus L.) was found on potted plants in a greenhouse in Yamaguchi city, Japan, in the late summer of 2008 and 2009. The symptoms were identical to those of rots caused by Choanephora species. The pathogen was isolated and identified as C. cucurbitarum (Berkeley and Ravenel) Thaxter. This new disease was named Choanephora rot (Kougai-kabi-byo) of Egyptian henbane.

European Journal of Chemistry, 2010

KEYWORDS Ageratum conyzoides L., is an annual herb with a long history of traditional medicinal u... more KEYWORDS Ageratum conyzoides L., is an annual herb with a long history of traditional medicinal uses in many countries in the world, especially in the tropical and subtropical regions. A wide range of chemical compounds including alkaloids, flavonoids, chromenes, benzofurans and terpenoids have been isolated from this species. Extracts and metabolites from this plant have been found to possess pharmacological and insecticidal activities. In continuation of our interest in the Egyptian medicinal plants, the reinvestigation of the methylenechloride extract of the air-dried aerial parts of Ageratum conyzoides afforded a new natural compound 1, pyrrolone, 5-ethoxy-1H-pyrrol-2(5H)-one, together with a known flavonoid. The structures of the compounds were determined by comprehensive NMR studies, including DEPT, COSY, HMQC, HMBC, and MS.

Biotechnology Letters, 2004

Feeding stemmadenine to Catharanthus roseuscell suspension culture resulted in the accumulation o... more Feeding stemmadenine to Catharanthus roseuscell suspension culture resulted in the accumulation of catharanthine, tabersonine and condylocarpine. Condylocarpine is not an intermediate in the pathway to catharanthine or tabersonine when it is fed to the cultures. The results support the hypothesis that stemmadenine is an intermediate in the pathway to catharanthine and tabersonine.