The Experts below are selected from a list of 723 Experts worldwide ranked by ideXlab platform
Sheau Farn Yeh - One of the best experts on this subject based on the ideXlab platform.
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Suppressive effects of Destruxin B on hepatitis B virus surface antigen gene expression in human hepatoma cells
Antiviral research, 1997Co-Authors: Hua-chien Chen, Chen-kung Chou, Chang-ming Sun, Sheau Farn YehAbstract:Destruxin B, a cyclodepsipeptide was originally identified as a plant pathogen from the fungus, Alternaria brassicae. We examined the antiviral activity of Destruxin B and found that it suppresses the expression of the hepatitis B viral surface antigen (HBsAg) gene in human hepatoma Hep3B cells which carry an integrated viral gene in its chromosome. In contrast, Destruxin B shows no cytotoxic effect on the viability of the cells. Furthermore, it can be shown that Destruxin B can reversibly suppress HBsAg production by Hep3B cells in a concentration-dependent manner with EC50 of 0.5 microM. Northern blot analysis indicates that the suppression of HBsAg gene expression by Destruxin B is mainly at the mRNA level. Destruxin B not only suppresses the endogenously expressed HBsAg in the Hep3B cells but also suppresses the HBsAg produced either from the stable transfected HBV DNA in another human hepatoma HuH-7 cell line which carry no endogenous HBV genome. These results suggest that Destruxin B may have future potential for development as a specific anti-HBV drug.
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Study of Structure–Activity Correlation in Destruxins, a Class of Cyclodepsipeptides Possessing Suppressive Effect on the Generation of Hepatitis B Virus Surface Antigen in Human Hepatoma Cells
Biochemical and biophysical research communications, 1996Co-Authors: Sheau Farn Yeh, Wei Pan, Geok-toh Ong, Aih-jing Chiou, Chyh-chong Chuang, Shyh-horng ChiouAbstract:A new Destruxin [Destruxin E2 chlorohydrin] was isolated from the culture medium of Metarrhizium anisopliae and its structure was determined by NMR spectroscopy and mass spectrometry. As compared with other Destruxins, the new Destruxin showed a lower suppressive activity on the production of hepatitis B virus surface antigen in human hepatoma Hep3B cells. NMR study coupled with molecular modeling by computer graphics has revealed that the hydrophobicity nature of the convex surface characteristic of all Destruxin molecules plays an important role in their biological activity.
Hermann Stuppner - One of the best experts on this subject based on the ideXlab platform.
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Quantitative Assessment of Destruxins from Strawberry and Maize in the Lower Parts per Billion Range: Combination of a QuEChERS-Based Extraction Protocol with a Fast and Selective UHPLC-QTOF-MS Assay.
Journal of agricultural and food chemistry, 2015Co-Authors: Judith Taibon, Sonja Sturm, Christoph Seger, Hermann Strasser, Hermann StuppnerAbstract:The entomopathogenic fungus Metarhizium brunneum is widely applied as a biological pest control agent. Consequently, its use has to be accompanied by a risk management approach, which includes the need to monitor the fate of its bioactive metabolites in the environment, for example, in treated crops. A fast and selective UHPLC-QTOF-MS method was developed to monitor the presence of secreted Destruxins in two model food plants for the application of this fungal biocontrol agent, namely, strawberry and maize. The liquid chromatography-mass spectrometric assay for Destruxin trace analysis is combined with a novel QuEChERS-based extraction protocol. The whole assay was optimized for the application in these crops, and it allows quantitative analysis of the major M. brunneum metabolites Destruxin A, 1, Destruxin B, 2, and Destruxin E, 3, down to the parts per billion range. In strawberry, limits of quantitation (LOQs) were found to be
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Quantitative Assessment of Destruxins from Strawberry and Maize in the Lower Parts per Billion Range: Combination of a QuEChERS-Based Extraction Protocol with a Fast and Selective UHPLC-QTOF-MS Assay
2015Co-Authors: Judith Taibon, Sonja Sturm, Christoph Seger, Hermann Strasser, Hermann StuppnerAbstract:The entomopathogenic fungus Metarhizium brunneum is widely applied as a biological pest control agent. Consequently, its use has to be accompanied by a risk management approach, which includes the need to monitor the fate of its bioactive metabolites in the environment, for example, in treated crops. A fast and selective UHPLC-QTOF-MS method was developed to monitor the presence of secreted Destruxins in two model food plants for the application of this fungal biocontrol agent, namely, strawberry and maize. The liquid chromatography–mass spectrometric assay for Destruxin trace analysis is combined with a novel QuEChERS-based extraction protocol. The whole assay was optimized for the application in these crops, and it allows quantitative analysis of the major M. brunneum metabolites Destruxin A, 1, Destruxin B, 2, and Destruxin E, 3, down to the parts per billion range. In strawberry, limits of quantitation (LOQs) were found to be
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Development of a fast and selective UHPLC-DAD-QTOF-MS/MS method for the qualitative and quantitative assessment of Destruxin profiles
Analytical and Bioanalytical Chemistry, 2014Co-Authors: Judith Taibon, Sonja Sturm, Christoph Seger, Hermann Strasser, Martin Parth, Hermann StuppnerAbstract:A fast and selective ultrahigh-performance liquid chromatography diode array detector (UHPLC-DAD) method combined with an off-line solid phase extraction (SPE) protocol was established to monitor Destruxins (dtxs), a secondary metabolite class of highly bioactive cyclic depsipeptides. Sample purification via SPE was tailored to remove both more polar and apolar matrix constituents by applying analyte class-selective washing and elution conditions. To separate and detect Destruxin congeners an UHPLC-DAD system hyphenated to a quadrupole–time-of-flight (Q-TOF) hybrid mass spectrometer was utilized. Analyses were performed on a sub-2-μm-particle-size RP-18 column with an acidified (0.02 % acetic acid) 12 min water/acetonitrile solvent gradient. In the dtx congener elution zone 22 chromatographic peaks were separated. Four of these were identified by comparison with reference materials as dtx A, dtx B, dtx E, and dtx E-diol; 16 were tentatively assigned as known or novel dtx congeners by the analysis of high resolution UHPLC-DAD-QTOF-MS/MS data recorded in the positive electrospray ionization (ESI) mode. The applicability of the UHPLC-DAD assay to investigate biological materials in a qualitative and quantitative manner was proven by the application of the platform to monitor the dtx production profile of three Metarhizium brunneum strain fungal culture broths.
Yellajyohula L. N. Murthy - One of the best experts on this subject based on the ideXlab platform.
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insecticidal activity of Destruxin a mycotoxin from metarhizium anisopliae hypocreales against spodoptera litura lepidoptera noctuidae larval stages
Pest Management Science, 2008Co-Authors: Sowjanya K Sree, Vadlamani Padmaja, Yellajyohula L. N. MurthyAbstract:BACKGROUND: The cyclodepsipeptide Destruxin produced by the entomopathogen Metarhizium anisopliae (Metch.) was administered by different methods, topical application, ingestion and a combination of the two, in an attempt to minimize the mycotoxin dose for efficient management of the insect pest Spodoptera litura (Fab.). RESULTS: The insecticidal activity of Destruxin on the larval stages of S. litura showed an ascending trend in LD50 values with increasing age. The value for 12-day-old larvae in the combined application assay was as low as 0.045 µg g−1 body weight of crude Destruxin from M-19 strain when compared with the corresponding values of 0.17 µg g−1 body weight in the ingestion assay and 0.237 µg g−1 body weight in the topical application assay. On the other hand, values were higher in the treatments with crude Destruxin from the low-virulence M-10 strain of M. anisopliae showing the least quantities of A and E components of Destruxin. CONCLUSION: Laboratory bioevaluation showed the combination assay of ingestion and topical application of crude Destruxin to be efficient in enhancing its insecticidal properties. The adopted combination assay apparently simulates application of the insecticide at field level. Quantitative differences between Destruxins from low- and high-virulence strains of M. anisopliae are in accordance with its presumed role in virulence. Copyright © 2007 Society of Chemical Industry
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Insecticidal activity of Destruxin, a mycotoxin from Metarhizium anisopliae (Hypocreales), against Spodoptera litura (Lepidoptera: Noctuidae) larval stages.
Pest management science, 2008Co-Authors: K. Sowjanya Sree, Vadlamani Padmaja, Yellajyohula L. N. MurthyAbstract:The cyclodepsipeptide Destruxin produced by the entomopathogen Metarhizium anisopliae (Metch.) was administered by different methods, topical application, ingestion and a combination of the two, in an attempt to minimize the mycotoxin dose for efficient management of the insect pest Spodoptera litura (Fab.). The insecticidal activity of Destruxin on the larval stages of S. litura showed an ascending trend in LD(50) values with increasing age. The value for 12-day-old larvae in the combined application assay was as low as 0.045 microg g(-1) body weight of crude Destruxin from M-19 strain when compared with the corresponding values of 0.17 microg g(-1) body weight in the ingestion assay and 0.237 microg g(-1) body weight in the topical application assay. On the other hand, values were higher in the treatments with crude Destruxin from the low-virulence M-10 strain of M. anisopliae showing the least quantities of A and E components of Destruxin. Laboratory bioevaluation showed the combination assay of ingestion and topical application of crude Destruxin to be efficient in enhancing its insecticidal properties. The adopted combination assay apparently simulates application of the insecticide at field level. Quantitative differences between Destruxins from low- and high-virulence strains of M. anisopliae are in accordance with its presumed role in virulence.
Shyh-horng Chiou - One of the best experts on this subject based on the ideXlab platform.
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Study of Structure–Activity Correlation in Destruxins, a Class of Cyclodepsipeptides Possessing Suppressive Effect on the Generation of Hepatitis B Virus Surface Antigen in Human Hepatoma Cells
Biochemical and biophysical research communications, 1996Co-Authors: Sheau Farn Yeh, Wei Pan, Geok-toh Ong, Aih-jing Chiou, Chyh-chong Chuang, Shyh-horng ChiouAbstract:A new Destruxin [Destruxin E2 chlorohydrin] was isolated from the culture medium of Metarrhizium anisopliae and its structure was determined by NMR spectroscopy and mass spectrometry. As compared with other Destruxins, the new Destruxin showed a lower suppressive activity on the production of hepatitis B virus surface antigen in human hepatoma Hep3B cells. NMR study coupled with molecular modeling by computer graphics has revealed that the hydrophobicity nature of the convex surface characteristic of all Destruxin molecules plays an important role in their biological activity.
Judith Taibon - One of the best experts on this subject based on the ideXlab platform.
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Quantitative Assessment of Destruxins from Strawberry and Maize in the Lower Parts per Billion Range: Combination of a QuEChERS-Based Extraction Protocol with a Fast and Selective UHPLC-QTOF-MS Assay.
Journal of agricultural and food chemistry, 2015Co-Authors: Judith Taibon, Sonja Sturm, Christoph Seger, Hermann Strasser, Hermann StuppnerAbstract:The entomopathogenic fungus Metarhizium brunneum is widely applied as a biological pest control agent. Consequently, its use has to be accompanied by a risk management approach, which includes the need to monitor the fate of its bioactive metabolites in the environment, for example, in treated crops. A fast and selective UHPLC-QTOF-MS method was developed to monitor the presence of secreted Destruxins in two model food plants for the application of this fungal biocontrol agent, namely, strawberry and maize. The liquid chromatography-mass spectrometric assay for Destruxin trace analysis is combined with a novel QuEChERS-based extraction protocol. The whole assay was optimized for the application in these crops, and it allows quantitative analysis of the major M. brunneum metabolites Destruxin A, 1, Destruxin B, 2, and Destruxin E, 3, down to the parts per billion range. In strawberry, limits of quantitation (LOQs) were found to be
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Quantitative Assessment of Destruxins from Strawberry and Maize in the Lower Parts per Billion Range: Combination of a QuEChERS-Based Extraction Protocol with a Fast and Selective UHPLC-QTOF-MS Assay
2015Co-Authors: Judith Taibon, Sonja Sturm, Christoph Seger, Hermann Strasser, Hermann StuppnerAbstract:The entomopathogenic fungus Metarhizium brunneum is widely applied as a biological pest control agent. Consequently, its use has to be accompanied by a risk management approach, which includes the need to monitor the fate of its bioactive metabolites in the environment, for example, in treated crops. A fast and selective UHPLC-QTOF-MS method was developed to monitor the presence of secreted Destruxins in two model food plants for the application of this fungal biocontrol agent, namely, strawberry and maize. The liquid chromatography–mass spectrometric assay for Destruxin trace analysis is combined with a novel QuEChERS-based extraction protocol. The whole assay was optimized for the application in these crops, and it allows quantitative analysis of the major M. brunneum metabolites Destruxin A, 1, Destruxin B, 2, and Destruxin E, 3, down to the parts per billion range. In strawberry, limits of quantitation (LOQs) were found to be
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Development of a fast and selective UHPLC-DAD-QTOF-MS/MS method for the qualitative and quantitative assessment of Destruxin profiles
Analytical and Bioanalytical Chemistry, 2014Co-Authors: Judith Taibon, Sonja Sturm, Christoph Seger, Hermann Strasser, Martin Parth, Hermann StuppnerAbstract:A fast and selective ultrahigh-performance liquid chromatography diode array detector (UHPLC-DAD) method combined with an off-line solid phase extraction (SPE) protocol was established to monitor Destruxins (dtxs), a secondary metabolite class of highly bioactive cyclic depsipeptides. Sample purification via SPE was tailored to remove both more polar and apolar matrix constituents by applying analyte class-selective washing and elution conditions. To separate and detect Destruxin congeners an UHPLC-DAD system hyphenated to a quadrupole–time-of-flight (Q-TOF) hybrid mass spectrometer was utilized. Analyses were performed on a sub-2-μm-particle-size RP-18 column with an acidified (0.02 % acetic acid) 12 min water/acetonitrile solvent gradient. In the dtx congener elution zone 22 chromatographic peaks were separated. Four of these were identified by comparison with reference materials as dtx A, dtx B, dtx E, and dtx E-diol; 16 were tentatively assigned as known or novel dtx congeners by the analysis of high resolution UHPLC-DAD-QTOF-MS/MS data recorded in the positive electrospray ionization (ESI) mode. The applicability of the UHPLC-DAD assay to investigate biological materials in a qualitative and quantitative manner was proven by the application of the platform to monitor the dtx production profile of three Metarhizium brunneum strain fungal culture broths.