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G. Trejo - One of the best experts on this subject based on the ideXlab platform.
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zn electrodeposition from an acidic chloride bath containing polyethyleneglycol mw 200 and Benzylideneacetone as additives
Journal of The Electrochemical Society, 2011Co-Authors: L E Moron, Y. Meas, Alia Mendez, J C Ballesteros, R Antanolopez, G Orozco, Raul Ortegaborges, G. TrejoAbstract:The influence of Polyethylene Glycol 200 (PEG200) or a PEG200/Benzylideneacetone (BDA) mixture on the mechanism of Zn deposition and nucleation kinetics was studied by voltammetry, chronoamperometry and atomic force microscopy (AFM). The addition of PEG200 or PEG200/BDA to the solution partially inhibited the reduction of Zn(II) at E ¼� 1.135 V vs. SCE. In the presence of PEG200/BDA, an additional reduction process was observed at E ¼� 1.24 V vs. SCE. Analysis of the nucleation processes indicated that, in all systems studied, the initial stage of Zn deposition was dominated by 3D diffusion-controlled nucleation. At E ¼� 1.132 V vs. SCE, the addition of PEG200 caused a reduction in the nucleation rate constant (A) and the number density of active sites (N0) with respect to the values obtained without additives. AFM analysis of coatings obtained at E ¼� 1.132 V vs. SCE, showed the formation of Zn clusters with different sizes distributed randomly on the surface. At E ¼� 1.243 V vs. SCE, both A and N0were higher for the solution containing the PEG200/BDA mixture than for the systems with PEG200 alone or without additives. AFM analysis revealed the formation of similarly sized Zn clusters uniformly distributed on the surface.
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effect of cl ions and Benzylideneacetone ethanol on the underpotential deposition of zinc in acidic media cyclic voltammetry and eqcm studies
Electrochimica Acta, 2005Co-Authors: P F Mendez, R. Ortega, Y. Meas, J R Lopez, Leonardo Salgado, G. TrejoAbstract:Abstract The influence of chloride ions and a Benzylideneacetone (BDA)/ethanol (EtOH) mixture on the underpotential deposition (UPD) of Zn2+ ions on Pt electrodes in acidic media was investigated by cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). In the potential region of the UPD of H and Zn, the surface coverage of Zn adatoms on Pt was evaluated based on the correspondence between charge and mass for several different solutions. In the absence of Cl− ions and BDA/EtOH, the maximum surface coverage of the Zn deposited by UPD was 0.29. In addition, in the presence of Cl− ions, the UPD of Zn2+ ions occurred simultaneously with the adsorption of Cl−, and the presence of Cl− did not modify the quantity of Zn deposited by UPD. In the presence of Cl− ions and BDA/EtOH, the maximum surface coverage of the Zn deposited by UPD was 0.16. The partial inhibition of the UPD of Zn2+ ions is associated with the adsorption of BDA/EtOH or products of the decomposition of BDA/EtOH during the UPD process.
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Electrochemical and AFM study of Zn electrodeposition in the presence of Benzylideneacetone in a chloride-based acidic bath
Journal of Applied Electrochemistry, 2005Co-Authors: P. Díaz-arista, R. Ortega, Y. Meas, G. TrejoAbstract:The influence of Benzylideneacetone (BDA) on the mechanism of zinc deposition and nucleation was studied by voltammetry, chronoamperometry and atomic force microscopy (AFM). The addition of BDA to the electrolyte solution partially inhibited (97%) the reduction of zinc at the potential E = −1.15 vs SCE/V, giving rise to an increase in the overpotential for the discharge of the metal ion. This leads to the existence of two reduction processes with different energies that involve the same species, ZnCl _4 ^2- . Analysis of chronoamperograms obtained in the absence and presence of BDA indicates that distinct nucleation mechanisms are involved during the initial stages of Zn deposition. In the absence of BDA, the transients are consistent with the model of 3D diffusion-controlled nucleation. In the presence of BDA, the transients exhibit a more complex form involving two growth processes. The first process, which occurs at short times, is explained in terms of a combination of three simultaneous nucleation processes: 2D progressive, 2D instantaneous, and 3D progressive nucleation, each limited by the incorporation of adatoms. The second process, which occurs at longer times, involves the three processes that occur at short times in conjunction with a principal contribution from a diffusion-controlled 3D nucleation mechanism. AFM imaging shows that the morphology of the deposited zinc depends on the applied electrode potential.
Yonggyun Kim - One of the best experts on this subject based on the ideXlab platform.
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Benzylideneacetone and other phenylethylamide bacterial metabolites induce apoptosis to kill insects
Journal of Asia-Pacific Entomology, 2020Co-Authors: Mahi Imam Mollah, Fatema Yeasmin, Yonggyun KimAbstract:Abstract Xenorhabdus and Photorhabdus are entomopathogenic bacteria that can induce immunosuppression against target insects by suppressing eicosanoid biosynthesis, leading to fatal septicemia. These bacteria can synthesize and release secondary metabolites such as Benzylideneacetone (BZA) and other phenylethylamide compounds that can inhibit phospholipase A2 (PLA2) and shut down eicosanoid biosynthesis. However, insecticidal activities of these bacterial metabolites remain unclear. Thus, the objective of this study was to assess cytotoxicities of BZA and seven other bacterial metabolites to insect cells. These eight bacterial metabolites exhibited significant cytotoxicities against an insect cell line Sf9 at micromolar range. Especially, BZA and cPY were highly potent at low micromolar range. When these eight bacterial metabolites were injected to hemocoels of Spodoptera exigua larvae, they significantly decreased total count of hemocytes. In Sf9 cell line and hemocytes, these bacterial metabolites induced cell membrane blebbings, apoptotic vesicles, and genomic DNA fragmentation. Terminal deoxyribonucleotidyl transferase nick end translation assay showed that these bacterial metabolites caused significant DNA breakages in cells in a dose-dependent manner. However, a pan caspase inhibitor treatment significantly rescued the cell death induced by these bacterial metabolites. Cytotoxicities of these bacterial metabolites were highly correlated with their insecticidal activities. These results indicate that the insecticidal activities of the bacterial metabolites may be induced by their apoptotic activities against hemocytes and other insect cells. Taken together, these results suggest that phenylethylamide compounds might have potential as novel insecticides.
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comparative analysis of Benzylideneacetone derived compounds on insect immunosuppressive and antimicrobial activities
Korean Journal of Applied Entomology, 2012Co-Authors: Samyeol Seo, Yong Pyo Hong, Wonsu Chun, Yonggyun KimAbstract:Benzylinedeneacetone (BZA) is a bacterial metabolite which is synthesized by at least two entomopathogenic bacteria, namely Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata. It has been shown to possess inhibitory effects on insect cellular and humoral immune responses as well as antimicrobial activities against various species of bacteria and fungi. However, its relatively high phytotoxicity, and nonsystematic effect have thus far prevented its development into an optimal pesticide. This study screened five different BZA derivatives in order to select an optimal compound, which would have relatively high solubility and low phytotoxicity while retaining sufficient degrees of the immunosuppressive and antimicrobial activities associated with BZA. Hydroxylation of the benzene ring of BZA was found to significantly suppress its immunosuppressive and antimicrobial activities. Transformation of the ketone of BZA by carboxylation also suppressed the inhibitory activities. However, a shortening of the aliphatic chain of BZA into acetate form (4-hydroxyphenylacetic acid: HPA) did not decrease the inhibitory activity. HPA also showed much less phytotoxicity against the hot pepper plant Capsicum annuum, when compared to BZA. This study identified an optimal BZA derivative, which exhibited relatively little phytotoxicity, but retained a high degree of inhibitory activity to suppress insect immune responses and antimicrobial activities against plant pathogens.
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Benzylideneacetone suppresses both cellular and humoral immune responses of spodoptera exigua and enhances fungal pathogenicity
Journal of Asia-pacific Entomology, 2011Co-Authors: Junga Park, Yonggyun KimAbstract:An entomopathogenic fungus, Beauveria bassiana, had significant insecticidal activity against the beet armyworm, Spodoptera exigua. However, it took almost one week to cause significant mortality. This study used a mixture treatment with an immunosuppressant to enhance the fungal pathogenicity. A bacterial metabolite, Benzylideneacetone (BZA), had a significant synergistic effect on the fungal pathogenicity against S. exigua, although it had little insecticidal activity by itself. The mixture treatment shortened median lethal time of B. bassiana by approximately 2 days. The synergistic activity of BZA on the pathogenicity of B. bassiana was induced by its immunosuppressive effects on both cellular and humoral antifungal responses of S. exigua. In response to B. bassiana, S. exigua larvae can form hemocytic nodules. Nodules were significantly suppressed by BZA treatment. Moreover, BZA inhibited expression of some antimicrobial peptide genes of S. exigua in response to fungal challenge. The immunosuppressive condition induced by BZA allowed B. bassiana to easily colonize and multiply in the hemocoel of treated larvae, which resulted in significant enhancement of the pathogenicity of B. bassiana.
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structure activity analysis of Benzylideneacetone for effective control of plant pests
Korean Journal of Applied Entomology, 2011Co-Authors: Samyeol Seo, Yong Pyo Hong, Mihyun Jun, Wonsu Chun, Sunghong Lee, Jiae Seo, Yonggyun KimAbstract:Benzylideneacetone (BZA) is a compound derived from culture broth of an entomopathogenic bacterium, Xenorhabdus nematophila (Xn). Its immunosuppressive activity is caused by its inhibitory activity against eicosanoid biosynthesis. This BZA is being developed as an additive to enhance control efficacy of other commercial microbial insecticides. This study was focused on the enhancement of the immunosuppressive activity of BZA by generating its chemical derivatives toward decrease of its hydrophobicity. Two hydroxylated BZA and one sugar-conjugated BZA were chemically synthesized. All derivatives had the inhibitory activities of BZA against phospholipase () and phenoloxidase (PO) of the diamondback moth, Plutella xylostella, but BZA was the most potent. Mixtures of any BZA derivative with Bacillus thuringiensis (Bt) significantly increased pathogenicity of Bt. BZA also inhibited colony growth of four plant pathogenic fungi. However, BZA derivatives (especially the sugar-conjugated BZA) lost the antifungal activity. These results indicated that BZA and its derivatives inhibited catalytic activities of two immune-associated enzymes ( and PO) of P. xylostella and enhanced Bt pathogenicity. We suggest its use to control plant pathogenic fungi.
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Benzylideneacetone an eicosanoid biosynthesis inhibitor enhances baculovirus pathogenicity in the diamondback moth plutella xylostella
Journal of Invertebrate Pathology, 2011Co-Authors: Jiwan Kim, Yonggyun KimAbstract:Benzylideneacetone (BZA) is a monoterpenoid compound produced by an entomopathogenic bacterium, Xenorhabdus nematophila. BZA inhibits phospholipase A(2) to suppress biosynthesis of eicosanoids that mediate immune responses in insects. In response to per os infection of Autographa californica multiple nucleopolyhedrosis virus (AcMNPV), the diamondback moth, Plutella xylostella, developed red spots on the midgut epithelium. The midgut exhibiting red spot formation suffered abnormal cell integrity, such as genomic DNA fragmentation and condensed spots in the nucleoplasm. The number of red spots increased with viral dose and incubation time after the viral treatment. BZA inhibited the formation of the midgut red spots in a dose-dependent manner. However, the inhibitory effect of BZA on the red spot formation was reversed by addition of arachidonic acid, suggesting that the red spot response may be mediated by eicosanoids. BZA treatment resulted in significant enhancement of AcMNPV occlusion body (OB) pathogenicity to P. xylostella.
Francesco Vizza - One of the best experts on this subject based on the ideXlab platform.
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synthesis of polymer supported rhodium i 1 3 bis diphenylphosphino propane moieties and their use in the heterogeneous hydrogenation of quinoline and Benzylideneacetone
Organometallics, 2001Co-Authors: Claudio Bianchini, Marco Frediani, Giuseppe Mantovani, Francesco VizzaAbstract:A p-styrenyl substituent attached to the ligand framework allows the diphosphine moiety −(C6H4)CH2OCH2C(CH3)(CH2PPh2)2 to be introduced as a pendant group in cross-linked styrene/divinylbenzene matrixes via free-radical copolymerization. In conjunction with rhodium(I), the POLYDIPHOS material forms an effective heterogeneous catalyst for the hydrogenation of Benzylideneacetone to benzylacetone and of quinoline to a mixture of 1,2,3,4-tetrahydroquinoline, 5,6,7,8-tetrahydroquinoline, and decahydroquinoline. The homogeneous behavior of related 1,3-bis(diphenylphosphino)propane rhodium complexes is different in both activity and selectivity.
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preparation characterization and performance of the supported hydrogen bonded ruthenium catalyst sulphos ru ncme 3 oso2cf3 sio2 comparisons with analogous homogeneous and aqueous biphase catalytic systems in the hydrogenation of Benzylideneacetone an
Organometallics, 2000Co-Authors: Claudio Bianchini, Vladimiro Dal Santo, Andrea Meli, Werner Oberhauser, Rinaldo Psaro And, Francesco VizzaAbstract:The Ru(II) complex [(sulphos)Ru(NCMe)3](OSO2CF3) (1) has been immobilized on partially dehydroxylated high-surface-area silica via hydrogen-bonding interactions between the silanol groups of the support and the SO3- groups from both the sulphos ligand and the triflate counteranion (sulphos = -O3S(C6H4)CH2C(CH2PPh2)3). Compound 1 has been authenticated in the solid state by a single-crystal X-ray analysis and in solution by NMR spectroscopy, while its silica-grafted form [(sulphos)Ru(NCMe)3](OSO2CF3)/SiO2 (1/SiO2) has been characterized by DRIFT and CP MAS 31P NMR studies. The supported hydrogen-bonded (SHB) complex 1/SiO2 is an effective and selective catalyst for the hydrogenation of Benzylideneacetone to benzylacetone and of benzonitrile to benzylidenebenzylamine in n-octane. No appreciable ruthenium leaching into the hydrocarbon phase was observed in either case. Analogous hydrogenation reactions catalyzed by either the aqueous-biphase catalyst 1 in water/n-octane or the homogeneous analogue [(triphos)...
Yong Pyo Hong - One of the best experts on this subject based on the ideXlab platform.
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comparative analysis of Benzylideneacetone derived compounds on insect immunosuppressive and antimicrobial activities
Korean Journal of Applied Entomology, 2012Co-Authors: Samyeol Seo, Yong Pyo Hong, Wonsu Chun, Yonggyun KimAbstract:Benzylinedeneacetone (BZA) is a bacterial metabolite which is synthesized by at least two entomopathogenic bacteria, namely Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata. It has been shown to possess inhibitory effects on insect cellular and humoral immune responses as well as antimicrobial activities against various species of bacteria and fungi. However, its relatively high phytotoxicity, and nonsystematic effect have thus far prevented its development into an optimal pesticide. This study screened five different BZA derivatives in order to select an optimal compound, which would have relatively high solubility and low phytotoxicity while retaining sufficient degrees of the immunosuppressive and antimicrobial activities associated with BZA. Hydroxylation of the benzene ring of BZA was found to significantly suppress its immunosuppressive and antimicrobial activities. Transformation of the ketone of BZA by carboxylation also suppressed the inhibitory activities. However, a shortening of the aliphatic chain of BZA into acetate form (4-hydroxyphenylacetic acid: HPA) did not decrease the inhibitory activity. HPA also showed much less phytotoxicity against the hot pepper plant Capsicum annuum, when compared to BZA. This study identified an optimal BZA derivative, which exhibited relatively little phytotoxicity, but retained a high degree of inhibitory activity to suppress insect immune responses and antimicrobial activities against plant pathogens.
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phospholipase a2 inhibitors synthesized by two entomopathogenic bacteria xenorhabdus nematophila and photorhabdus temperata subsp temperata
Applied and Environmental Microbiology, 2012Co-Authors: Yong Pyo HongAbstract:The entomopathogenic bacteria Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata suppress insect immune responses by inhibiting the catalytic activity of phospholipase A2 (PLA2), which results in preventing biosynthesis of immune-mediating eicosanoids. This study identified PLA2 inhibitors derived from culture broths of these two bacteria. Both X. nematophila and P. temperata subsp. temperata culture broths possessed significant PLA2-inhibitory activities. Fractionation of these bacterial metabolites in the culture broths using organic solvent and subsequent chromatography purified seven potent PLA2 inhibitors, three of which (Benzylideneacetone [BZA], proline-tyrosine [PY], and acetylated phenylalanine-glycine-valine [FGV]) were reported in a previous study. Four other compounds (indole, oxindole, cis-cyclo-PY, and p-hydroxyphenyl propionic acid) were identified and shown to significantly inhibit PLA2. X. nematophila culture broth contained these seven compounds, while P. temperata subsp. temperata culture broth contained three compounds (BZA, acetylated FGV, and cis-cyclo-PY). BZA was detected in the largest amount among these PLA2 compounds in both bacterial culture broths. All seven bacterial metabolites also showed significant inhibitory activities against immune responses, such as phenoloxidase activity and hemocytic nodulation; BZA was the most potent. Finally, this study characterized these seven compounds for their insecticidal activities against the diamondback moth, Plutella xylostella. Even though these compounds showed relatively low toxicities to larvae, they significantly enhanced the pathogenicity of Bacillus thuringiensis. This study reports bacterial-origin PLA2 inhibitors, which would be applicable for developing novel insecticides.
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structure activity analysis of Benzylideneacetone for effective control of plant pests
Korean Journal of Applied Entomology, 2011Co-Authors: Samyeol Seo, Yong Pyo Hong, Mihyun Jun, Wonsu Chun, Sunghong Lee, Jiae Seo, Yonggyun KimAbstract:Benzylideneacetone (BZA) is a compound derived from culture broth of an entomopathogenic bacterium, Xenorhabdus nematophila (Xn). Its immunosuppressive activity is caused by its inhibitory activity against eicosanoid biosynthesis. This BZA is being developed as an additive to enhance control efficacy of other commercial microbial insecticides. This study was focused on the enhancement of the immunosuppressive activity of BZA by generating its chemical derivatives toward decrease of its hydrophobicity. Two hydroxylated BZA and one sugar-conjugated BZA were chemically synthesized. All derivatives had the inhibitory activities of BZA against phospholipase () and phenoloxidase (PO) of the diamondback moth, Plutella xylostella, but BZA was the most potent. Mixtures of any BZA derivative with Bacillus thuringiensis (Bt) significantly increased pathogenicity of Bt. BZA also inhibited colony growth of four plant pathogenic fungi. However, BZA derivatives (especially the sugar-conjugated BZA) lost the antifungal activity. These results indicated that BZA and its derivatives inhibited catalytic activities of two immune-associated enzymes ( and PO) of P. xylostella and enhanced Bt pathogenicity. We suggest its use to control plant pathogenic fungi.
Sony Shrestha - One of the best experts on this subject based on the ideXlab platform.
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bacterial metabolites of an entomopathogenic bacterium xenorhabdus nematophila inhibit a catalytic activity of phenoloxidase of the diamondback moth plutella xylostella
Journal of Microbiology and Biotechnology, 2011Co-Authors: Chrisitine Jisso Song, Sony ShresthaAbstract:: A monoterpenoid compound, Benzylideneacetone (BZA), is identified from bacterial metabolites synthesized by an entomopathogenic bacterium, Xenorhabdus nematophila. It inhibits phospholipase A2 of target insects to shut down biosynthesis of various eicosanoids, which play significant roles in insect immunity. This study discovered another novel activity of BZA that directly inhibited phenoloxidase (PO) activity required for immune-associated melanization. When it was injected into larvae of Plutella xylostella, it suppressed PO activity in the plasma by inhibiting its activation from inactive proPO. However, BZA did not influence on gene expression of PO, which was analyzed by RT-PCR using gene-specific primers designed from a partial cDNA sequence of PO of the P. xylostella identified in this study. To test a direct inhibitory activity of BZA against PO, the activated PO of P. xylostella was prepared from the hemolymph collected from the larvae challenged by bacteria. When the activated PO was incubated in vitro with BZA, it was inhibited in a dose-dependent manner. The inhibition of PO by BZA was recovered by addition of increasing amounts of substrate, L-3,4-dihydroxyphenylalanine. Three other known bacterial metabolites containing a benzene propane core structure synthesized by X. nematophila also inhibited the PO enzyme activity. However, modification of the core structure by hydroxylation of BZA lost its strong inhibitory activity against the activated PO.
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an entomopathogenic bacterium xenorhabdus nematophila inhibits hemocyte phagocytosis of spodoptera exigua by inhibiting phospholipase a2
Journal of Invertebrate Pathology, 2007Co-Authors: Sony ShresthaAbstract:Abstract Phagocytosis is a hemocytic behavior against bacterial infection. An entomopathogenic bacterium, Xenorhabdus nematophila, inhibits immune responses of target insects and causes hemolymph septicemia. This study analyzed how X. nematophila could inhibit phagocytosis to increase its pathogenicity. Granular cells and plasmatocytes were the main phagocytic hemocytes of Spodoptera exigua determined by observing fluorescence-labeled bacteria in the cytosol. X. nematophila significantly inhibited phagocytosis of both hemocytes, while heat-killed X. nematophila lost its inhibitory potency. However, co-injection of X. nematophila with arachidonic acid did not show any significant inhibition of hemocyte phagocytosis. In fact, hemocytes of S. exigua infected with X. nematophila showed significant reduction in phospholipase A2 (PLA2) activity. Dexamethasone, a specific PLA2 inhibitor, significantly inhibited phagocytosis of both cell types. However, the inhibitory effect of dexamethasone was recovered by addition of arachidonic acid. Incubation of hemocytes with Benzylideneacetone, a metabolite of X. nematophila, inhibited phagocytosis in a dose-dependent manner. These results suggest that X. nematophila produces and secretes PLA2 inhibitor(s), which in turn inhibit the phagocytic response of hemocytes.