This article discusses how methanol (MeOH) affects ascorbate (AsA) levels and related gene expression in Oncidium orchids. The study found that a low concentration of MeOH (50 mM) triggered hydrogen peroxide (H2O2) production and increased expression of AsA biosynthesis genes. However, a high MeOH concentration was toxic and depleted AsA levels. The increased gene expression from low MeOH levels was blocked by inhibitors of alcohol oxidase and NADPH oxidase, suggesting H2O2 is a signaling molecule regulating AsA gene expression in response to MeOH. The results help explain the mechanism by which MeOH stimulates AsA production in Oncidium at the molecular level.
The study aimed to detect and analyze novel diterpenoid dioxygenase genes (ditA1) involved in the degradation of resin acids, which are naturally produced by trees and released during wood pulping processes. Using newly designed PCR primers, ditA1 homolog genes were amplified from various Pseudomonas, Burkholderia, and Cupriavidus strains. All isolates containing a ditA1 homolog could grow on dehydroabietic acid and expressed ditA1 constitutively or in response to dehydroabietic acid, demonstrating their role in degradation. Evolutionary analyses indicate ditA1 and gyrB genes have coevolved from ancestral variants in Pseudomonas, Burkholderia, and Cupriavid
Nitrate Reductases: Structure, Functions, and Effect of Stress FactorsIPN
Nitrogen is essential for life and its biogeochemical cycle involves many processes. There are four main types of nitrate reductases - eukaryotic assimilatory, bacterial cytoplasmic assimilatory, membrane-bound respiratory, and periplasmic dissimilatory. They contain molybdenum and molybdenum cofactor in their active sites and catalyze the reduction of nitrate to nitrite. Bacterial nitrate reductases are further classified based on their electron donors as either ferredoxin-dependent or NADH-dependent. Genes encoding the enzymes for nitrate assimilation are often organized in operons along with those for nitrate and nitrite transporters.
An Engineered Monolignol 4-O-Methyltransferase Depresses Lignin Biosynthesis ...Wadud Bhuiya
- An artificial monolignol 4-O-methyltransferase was created using iterative saturation mutagenesis to modify the structure and function of an isoeugenol O-methyltransferase (IEMT).
- Expressing this engineered enzyme in plants etherified the para-hydroxyls of lignin monomers, preventing them from participating in lignin polymerization and reducing lignin content. Transgenic plants also accumulated novel 4-O-methylated phenolic compounds.
- Lower lignin levels resulted in higher saccharification yields from transgenic plant biomass, demonstrating this protein engineering approach can modulate phenylpropanoid biosynthesis and improve cell wall digestibility.
Meulepas, 2010, Trace Methane Oxidation And The Methane Dependency Of Sulfate...roelmeulepas
This research article investigates trace methane oxidation and the methane dependency of sulfate reduction in three types of anaerobic granular sludge. The researchers found that all sludge samples anaerobically oxidized 13C-labeled methane to 13C-labeled carbon dioxide, while also producing endogenous methane. Labeled methane oxidation rates followed methane production rates. The presence of sulfate inhibited both labeled methane oxidation and methanogenesis. Labeled methane oxidation was linked to methanogenesis, referred to as trace methane oxidation. The ratio of labeled methane oxidation to methanogenesis increased with higher methane partial pressures. Higher methane partial pressures also increased sulfate reduction and inhibited methanogenesis, giving sulfate reducers a competitive advantage over methanogens for common substrates.
The document discusses methods to enhance the biodegradation of polylactic acid (PLA). It analyzes modifications to PLA's physical properties and amending the environment with various factors like stimulants. It summarizes that biodegradation of PLA mainly occurs through hydrolysis of ester bonds and is induced by microorganisms like certain actinomycetes, bacteria, and fungi. Key factors like temperature, pH, humidity, and oxygen levels also affect the degradation rate. While PLA is biodegradable, the process is often slow under natural conditions.
2010 engineering tocopherol biosynthetic pathway in arabidopsis leavesAgrin Life
This study genetically engineered the tocopherol biosynthetic pathway in Arabidopsis thaliana by overexpressing five genes (HPPD, VTE2, VTE3, VTE1, and VTE4) involved in tocopherol production, both individually and in combinations. The results showed that elevated expression of these biosynthetic genes affected total tocopherol content and composition. Additionally, engineering the tocopherol pathway also impacted endogenous ascorbate and glutathione pools in the leaves. Further analysis found that genes in the Halliwell-Asada antioxidant cycle were upregulated. These findings provide insight into the relationship between lipid-soluble vitamin E and water-soluble antioxidants vitamin C and
The study aimed to detect and analyze novel diterpenoid dioxygenase genes (ditA1) involved in the degradation of resin acids, which are naturally produced by trees and released during wood pulping processes. Using newly designed PCR primers, ditA1 homolog genes were amplified from various Pseudomonas, Burkholderia, and Cupriavidus strains. All isolates containing a ditA1 homolog could grow on dehydroabietic acid and expressed ditA1 constitutively or in response to dehydroabietic acid, demonstrating their role in degradation. Evolutionary analyses indicate ditA1 and gyrB genes have coevolved from ancestral variants in Pseudomonas, Burkholderia, and Cupriavid
Nitrate Reductases: Structure, Functions, and Effect of Stress FactorsIPN
Nitrogen is essential for life and its biogeochemical cycle involves many processes. There are four main types of nitrate reductases - eukaryotic assimilatory, bacterial cytoplasmic assimilatory, membrane-bound respiratory, and periplasmic dissimilatory. They contain molybdenum and molybdenum cofactor in their active sites and catalyze the reduction of nitrate to nitrite. Bacterial nitrate reductases are further classified based on their electron donors as either ferredoxin-dependent or NADH-dependent. Genes encoding the enzymes for nitrate assimilation are often organized in operons along with those for nitrate and nitrite transporters.
An Engineered Monolignol 4-O-Methyltransferase Depresses Lignin Biosynthesis ...Wadud Bhuiya
- An artificial monolignol 4-O-methyltransferase was created using iterative saturation mutagenesis to modify the structure and function of an isoeugenol O-methyltransferase (IEMT).
- Expressing this engineered enzyme in plants etherified the para-hydroxyls of lignin monomers, preventing them from participating in lignin polymerization and reducing lignin content. Transgenic plants also accumulated novel 4-O-methylated phenolic compounds.
- Lower lignin levels resulted in higher saccharification yields from transgenic plant biomass, demonstrating this protein engineering approach can modulate phenylpropanoid biosynthesis and improve cell wall digestibility.
Meulepas, 2010, Trace Methane Oxidation And The Methane Dependency Of Sulfate...roelmeulepas
This research article investigates trace methane oxidation and the methane dependency of sulfate reduction in three types of anaerobic granular sludge. The researchers found that all sludge samples anaerobically oxidized 13C-labeled methane to 13C-labeled carbon dioxide, while also producing endogenous methane. Labeled methane oxidation rates followed methane production rates. The presence of sulfate inhibited both labeled methane oxidation and methanogenesis. Labeled methane oxidation was linked to methanogenesis, referred to as trace methane oxidation. The ratio of labeled methane oxidation to methanogenesis increased with higher methane partial pressures. Higher methane partial pressures also increased sulfate reduction and inhibited methanogenesis, giving sulfate reducers a competitive advantage over methanogens for common substrates.
The document discusses methods to enhance the biodegradation of polylactic acid (PLA). It analyzes modifications to PLA's physical properties and amending the environment with various factors like stimulants. It summarizes that biodegradation of PLA mainly occurs through hydrolysis of ester bonds and is induced by microorganisms like certain actinomycetes, bacteria, and fungi. Key factors like temperature, pH, humidity, and oxygen levels also affect the degradation rate. While PLA is biodegradable, the process is often slow under natural conditions.
2010 engineering tocopherol biosynthetic pathway in arabidopsis leavesAgrin Life
This study genetically engineered the tocopherol biosynthetic pathway in Arabidopsis thaliana by overexpressing five genes (HPPD, VTE2, VTE3, VTE1, and VTE4) involved in tocopherol production, both individually and in combinations. The results showed that elevated expression of these biosynthetic genes affected total tocopherol content and composition. Additionally, engineering the tocopherol pathway also impacted endogenous ascorbate and glutathione pools in the leaves. Further analysis found that genes in the Halliwell-Asada antioxidant cycle were upregulated. These findings provide insight into the relationship between lipid-soluble vitamin E and water-soluble antioxidants vitamin C and
Enzymes are biological catalysts that lower the activation energy of reactions. They consist of proteins or glycoproteins and have active sites that facilitate reactions. There are six main classes of enzymes based on the type of reaction catalyzed: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. Enzymes play important roles in bioremediation by facilitating the breakdown of environmental pollutants like phenols, azo dyes, chlorinated compounds, and petroleum hydrocarbons through reactions like oxidation, reduction, hydrolysis, and cleavage. Key enzyme groups involved in bioremediation include oxygenases, laccases, peroxidases, and hydroly
1) The document describes the total synthesis of the natural product 10-hydroxyasimicin, which contains a bis-THF motif in its central core.
2) A key step was the development of a template approach to link two alkenol building blocks and induce stereocontrol during ring-closing metathesis to generate the bis-THF framework.
3) The synthesis involved coupling the building blocks, ring-closing metathesis, asymmetric dihydroxylation, macrocycle opening and elaboration to install side chains, and final coupling and deprotection to yield the target natural product.
Biosynthesis of deuterium labeled phenylalanine. facultativeAlexander Decker
This document describes a study that used the facultative methylotrophic bacterium Brevibacterium methylicum to biosynthesize deuterium-labeled phenylalanine. The bacterium was adapted to grow in increasingly concentrated deuterated water and deuterated methanol media. This allowed the biosynthesis of phenylalanine with varying levels of deuterium enrichment, from 17% to 75% deuterium content. Mass spectrometry analysis confirmed the incorporation of deuterium into the benzyl group of the phenylalanine molecule. The method provides a cost-effective way to produce specifically deuterated amino acids for biomedical applications using bacterial growth on deuterated substrates.
2008 molecular mechanism of enzymatic allene oxide cyclization in plantsAgrin Life
This document summarizes the molecular mechanism of enzymatic allene oxide cyclization in plants. It discusses allene oxide cyclase (AOC), an enzyme that catalyzes the cyclization of 12,13-epoxy-9(Z),11,15(Z)-octadecatrienoic acid (12,13-EOT) to produce the oxylipin 12-oxo-phytodienoic acid (OPDA) in the jasmonic acid biosynthesis pathway. The review focuses on the crystal structure of AOC2 from Arabidopsis thaliana and putative binding sites for its unstable substrate 12,13-EOT. It also discusses possible intermolecular rearrangements during the cyclization reaction
Microbial Biotransformation of xenobiotic compoundsPrashant Singam
This document discusses microbial biotransformation of xenobiotic compounds. It defines xenobiotics as man-made chemicals not naturally produced by living organisms. While microbes can degrade many xenobiotics, some compounds called recalcitrant xenobiotics remain non-degradable. The document outlines types of recalcitrant compounds and how their properties make them resistant to degradation. It also describes various pathways microbes use to transform and degrade xenobiotics through aerobic and anaerobic processes.
solid phase synthesis Presentation by komalKomal Rajgire
The document summarizes solid phase synthesis. It begins with an introduction describing how solid phase synthesis involves coupling reagents to a solid support to perform multi-step reactions leading to a target molecule. It then discusses various aspects of planning solid phase synthesis such as suitable resin supports, linkers, protective groups, and monitoring reactions. Examples of resin types, linkers, and protective groups are provided. The document concludes by outlining advantages such as simplified purification and green chemistry principles, as well as disadvantages such as potential low reaction rates. Applications mentioned include combinatorial synthesis, peptide synthesis, and DNA synthesis.
Este es uno de los estudios científicos, recientemente publicados, que se ha enfocado en registrar la cantidad del compuesto 4-Metilidimazol que se encuentra en las bebidas de Cola y en la cerveza oscura. El compuesto 4-Metilidimazol es un subproducto cancerígeno que se encuentra en el colorante Caramelo IV utilizado en estas bebidas. El estudio reconoce que la mayor ingesta que se da de este compuesto es a través de las bebidas de Cola. Estima que en los Estados Unidos el consumo promedio diario de bebidas de Cola puede representar una ingesta de 342 microgramos diarios de 4-Metilidimazol. Esta cantidad significa varias veces el nivel máximo recomendado como seguro de ingesta de este compuesto sugerido por la autoridad de California, para todo un día que es de 16 microgramos al día. El estudio reporta que una sola lata de bebida de Cola puede contener entre 12.95 y 214.55 microgramos de 4-Metilidimazol.
comprehensive presentation on Detoxification of xenobiotics in human body.This presentation is designed for undergraduate medical ,dental ,biotechnology & pharmacology students for self study.Presentation has Definition of detoxification , classification of toxic substances .Detoxification of endogenous & exogenous toxic substances along with molecular mechanism involved is presented here.Metabolism of xenobiotic (detoxification)
by oxidation. reduction , hydrolysis& conjugation is illustrated with suitable examples.Characteristics of cytochrome P450& its mode of action are described.Google images are used to support the text for better understanding.
1) Novel compounds called O,O-diethyl 1-benzamido-2,2-biscarbamoylethanephosphonates were synthesized as substrates for HIV-1 protease (PR) to exploit activation of the phosphonate group.
2) One compound, O,O-diethyl 1-benzamido-2,2-bis[(1S)-N-(1-benzyl-2-hydroxyethyl)carbamoyl]ethanephosphonate, showed moderate anti-HIV activity in vitro. Its depsipeptide analogue inhibited HIV-1 PR with an IC50 of 31 μM.
3) The phosphonate group of these compounds was designed
Chemical conversion of a substance mediated by living organisms or enzymes
Can result in DETOXIFICATION and BIOACTIVATION
Vital to survive
Key in defense mechanism
Understanding the adsorption mechanisms in nanostructured polymer films has become crucial for their use in technological applications, since film properties vary considerably with the experimental conditions utilized for film fabrication. In this paper, we employ small-angle X-ray
scattering (SAXS) to investigate solutions of polyanilines and correlate the chain conformations with morphological features of the nanostructured films obtained with atomic force microscopy (AFM). It is shown that aggregates formed already in solution affect the film morphology; in
particular, at early stages of adsorption film morphology appears entirely governed by the chain conformation in solution and adsorption of aggregates. We also use SAXS data for modeling poly(o-ethoxyaniline) (POEA) particle shape through an ab initio procedure based on simulated
annealing using the dummy atom model (DAM), which is then compared to the morphological features of POEA films fabricated with distinct pHs and doping acids. Interestingly, when the derivative POEA is doped with p-toluene sulfonic acid (TSA), the resulting films exhibit a fibrillar morphology—seen with atomic force microscopy and transmission electron microscopy—that is consistent with the cylindrical shape inferred from the SAXS data. This is in contrast with the globular morphology observed for POEA films doped with other acids.
The document summarizes the rational design of microbial chemical factories to produce useful compounds. It discusses using metabolic engineering techniques to improve natural producers of compounds like antibiotics and organic acids. Novel pathway design is described using retro-biosynthetic approaches and enzyme selection. Glucaric acid is presented as a model compound produced via a novel 3 step pathway from cloned enzymes. Further optimization using scaffolding to co-localize enzymes increased titer. 3-Hydroxybutyrolactone is also discussed as a target compound currently produced chemically that could potentially be made through a biological pathway.
SiO2@FeSO4 nano composite: A recoverable nano-catalyst for eco-friendly synth...Iranian Chemical Society
Various aldoximes and ketoximes synthesis of corresponding aldehydes and ketones in the presence of SiO2@FeSO4 nano composite as recoverable nano catalyst and NH2OH·HCl. The SiO2@FeSO4 nano composite system was carried out between 10 to 15 min in oil bath (70-80 °C) under solvent-free condition in excellent yields in addition this protocol can be used for industrial scales. This method offers some advantages in term of clean reaction conditions, easy work-up procedure, short reaction time, applied to convert α-diketones to α-diketoximes (as longer than other carbonyl compounds), α,β-unsaturated aldehydes and ketones to corresponding oximes and suppression of any side product. So we think that NH2OH•HCl/SiO2@FeSO4 nano composite system could be considered a new and useful addition to the present methodologies in this area. Structure of products and nano composite elucidation was carried out by 1H NMR, 13C NMR, FT-IR, scanning electron microscopy (SEM).
A Novel Statistical Method for Thermostable Proteins Discrimination IJORCS
This document summarizes a novel statistical method for discriminating between thermostable proteins. The method uses amino acid frequency, dipeptide frequency, and physical-chemical features extracted from protein sequences to classify proteins as mesophilic, thermophilic, or hyper-thermophilic. The researchers tested the effect of each set of features individually and combined on classification accuracy. Their results show the proposed method using all feature types together achieved the best performance, correctly classifying over 90% of proteins on average.
This document reviews drug discovery efforts to develop new antimicrobials by targeting the diaminopimelic acid (DAP) biosynthesis pathway in bacteria. It discusses how DAP is an essential component of bacterial cell walls but not mammalian cells, making enzymes in the DAP pathway potential drug targets. The review focuses on substrate-based inhibitors of DAP pathway enzymes and how understanding the enzymology could aid inhibitor design. Developing inhibitors that selectively block DAP biosynthesis in resistant bacteria could lead to new, less toxic antimicrobial therapies.
This document discusses xenobiotics, or foreign chemicals, and their metabolism in the body. Xenobiotics metabolism mainly occurs in the liver and involves two phases - phase I and phase II reactions. Phase I reactions use enzymes like cytochrome P450 to increase a chemical's water solubility, while phase II reactions further process chemicals through conjugation, such as by adding glucuronic acid or glutathione. Understanding xenobiotic metabolism is important for pharmacology, toxicology, and drug interactions.
This document summarizes the synthesis and characterization of the oxomolybdenum mono-ene-1,2-dithiolate complex (Tp*)MoO(bdtCl2) (3). X-ray crystallography showed compound 3 crystallizes in the monoclinic space group P21/c, with a distorted octahedral coordination geometry around the Mo atom. IR, EPR, and electronic absorption spectroscopy indicate the chlorine substituents do not significantly perturb the electronic structure of the Mo(V) center, but solution redox potentials and gas-phase ionization energies are sensitive to remote substituent effects. The coordination environment of 3 is similar to the related complex (Tp*)MoO(
More detalis abot vitamins and for buying visit at leonutra.com
vitamin cofactors - 5
are vitamins coenzymes - 16
coenzyme vitamins - 7
are vitamins cofactors - 7
what function do many b vitamins serve in the production of energy - 22
which vitamins are coenzymes - 6
coenzymes and vitamins - 7
cofactor vitamin - 5
coenzyme a vitamin - 14
coenzyme a is derived from which of the following vitamins - 8
what vitamin forms a part of coenzyme a - 10
the coenzyme fad is formed from what vitamin - 12
the vitamin that is part of the coenzyme nad is - 11
vitamins and coenzymes - 9
vitamin d coenzyme - 7
does water function as a coenzyme - 15
acetyl coa vitamin - 23
flavin adenine dinucleotide is a coenzyme form of the vitamin - 24
folate coenzymes are needed for the - 18
a cofactor that contains carbon is known as a - 19
how do vitamins help enzymes - 23
which vitamin does not act as a coenzyme - 11
b vitamins act as parts of coenzymes - 12
vitamin c cofactor - 22
vitamins and coenzymes in biochemistry - 15
cofactors for b12 absorption - 17
coenzyme form of vitamin c - 6
coenzymes and vitamins relationship - 5
coenzyme vitamin - 14
coenzyme of vitamin b1 - 13
b12 cofactors - 24
the coenzyme form of riboflavin is - 19
the signs and symptoms of riboflavin deficiency are known collectively as - 24
thiamine cofactor - 17
the vitamin that functions as part of coenzyme a is - 17
vitamins as coenzymes - 14
vitamin k coenzyme - 15
vitamin cofactor - 5
vitamin c coenzyme - 13
vitamins work with enzymes to initiate - 16
vitamins and cofactors - 5
vitamin a coenzyme - 12
mineral cofactors - 14
minerals and vitamins share which characteristic - 26
are b vitamins coenzymes
This document summarizes a study that investigated the degradation of halogenated organic compounds (haloorganics) by iron porphyrin complexes as biomimetic models of marine microbial pathways. The study reacted various iodinated substrates with different iron porphyrin complexes and monitored the reactions using UV-Vis spectroscopy and gas chromatography-mass spectrometry. The results showed that the iodo substrates reacted fastest, followed by chloro and bromo substrates. Products identified included methane, ethylene, and the corresponding dehalogenated alkene. Reaction rates correlated with the redox potential of the iron complex, with higher redox potentials corresponding to faster rates. The study provides insights into abiotic marine degradation of haloorgan
The document describes research on peroxidase enzymes extracted from miswak, a chewing stick made from Salvadora persica roots and stems. Key findings:
- Peroxidase activity was highest in the peel of the stem and root without peel, which is commonly used.
- Three peroxidases (POI, POII, POIII) were separated from root without peel extracts via ion exchange chromatography. POII had the highest activity.
- POII was further purified via gel filtration, found to have a molecular weight of 70 kDa and optimal pH/temperature of 5.5/40°C. It was stable at 10-40°C.
Meulepas, 2010, Effect Of Methanogenic Substrates On Anaerobic Oxidation Of M...roelmeulepas
This document describes a study that tested six methanogenic substrates (acetate, formate, methanol, carbon monoxide, hydrogen, and methanethiol) as potential interspecies electron carriers (IECs) in anaerobic oxidation of methane (AOM) coupled to sulfate reduction. The substrates were added to an enrichment culture containing archaea and bacteria involved in AOM and sulfate reduction. The presence of acetate, formate, hydrogen, and carbon monoxide enhanced sulfate reduction but did not inhibit AOM or trigger methanogenesis. Methanol did not enhance sulfate reduction or inhibit AOM. Methanethiol completely inhibited both AOM and sulfate reduction. Based on these results, the tested substrates could not solely support the electron
This study analyzed changes in the microbial community at different stages of an air sparging bioremediation treatment of soil highly contaminated with jet fuel and BTEX compounds. Microbial community composition and biomass were monitored using phospholipid fatty acid profiling and 16S rRNA gene analysis. Initially, the community was dominated by Pseudomonads under high contamination. As treatment progressed and contaminant levels decreased, biomass and diversity increased. The community shifted to a more complex composition with diverse bacterial taxa, indicating selection pressure from contaminants was reduced as bioremediation succeeded.
Enzymes are biological catalysts that lower the activation energy of reactions. They consist of proteins or glycoproteins and have active sites that facilitate reactions. There are six main classes of enzymes based on the type of reaction catalyzed: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. Enzymes play important roles in bioremediation by facilitating the breakdown of environmental pollutants like phenols, azo dyes, chlorinated compounds, and petroleum hydrocarbons through reactions like oxidation, reduction, hydrolysis, and cleavage. Key enzyme groups involved in bioremediation include oxygenases, laccases, peroxidases, and hydroly
1) The document describes the total synthesis of the natural product 10-hydroxyasimicin, which contains a bis-THF motif in its central core.
2) A key step was the development of a template approach to link two alkenol building blocks and induce stereocontrol during ring-closing metathesis to generate the bis-THF framework.
3) The synthesis involved coupling the building blocks, ring-closing metathesis, asymmetric dihydroxylation, macrocycle opening and elaboration to install side chains, and final coupling and deprotection to yield the target natural product.
Biosynthesis of deuterium labeled phenylalanine. facultativeAlexander Decker
This document describes a study that used the facultative methylotrophic bacterium Brevibacterium methylicum to biosynthesize deuterium-labeled phenylalanine. The bacterium was adapted to grow in increasingly concentrated deuterated water and deuterated methanol media. This allowed the biosynthesis of phenylalanine with varying levels of deuterium enrichment, from 17% to 75% deuterium content. Mass spectrometry analysis confirmed the incorporation of deuterium into the benzyl group of the phenylalanine molecule. The method provides a cost-effective way to produce specifically deuterated amino acids for biomedical applications using bacterial growth on deuterated substrates.
2008 molecular mechanism of enzymatic allene oxide cyclization in plantsAgrin Life
This document summarizes the molecular mechanism of enzymatic allene oxide cyclization in plants. It discusses allene oxide cyclase (AOC), an enzyme that catalyzes the cyclization of 12,13-epoxy-9(Z),11,15(Z)-octadecatrienoic acid (12,13-EOT) to produce the oxylipin 12-oxo-phytodienoic acid (OPDA) in the jasmonic acid biosynthesis pathway. The review focuses on the crystal structure of AOC2 from Arabidopsis thaliana and putative binding sites for its unstable substrate 12,13-EOT. It also discusses possible intermolecular rearrangements during the cyclization reaction
Microbial Biotransformation of xenobiotic compoundsPrashant Singam
This document discusses microbial biotransformation of xenobiotic compounds. It defines xenobiotics as man-made chemicals not naturally produced by living organisms. While microbes can degrade many xenobiotics, some compounds called recalcitrant xenobiotics remain non-degradable. The document outlines types of recalcitrant compounds and how their properties make them resistant to degradation. It also describes various pathways microbes use to transform and degrade xenobiotics through aerobic and anaerobic processes.
solid phase synthesis Presentation by komalKomal Rajgire
The document summarizes solid phase synthesis. It begins with an introduction describing how solid phase synthesis involves coupling reagents to a solid support to perform multi-step reactions leading to a target molecule. It then discusses various aspects of planning solid phase synthesis such as suitable resin supports, linkers, protective groups, and monitoring reactions. Examples of resin types, linkers, and protective groups are provided. The document concludes by outlining advantages such as simplified purification and green chemistry principles, as well as disadvantages such as potential low reaction rates. Applications mentioned include combinatorial synthesis, peptide synthesis, and DNA synthesis.
Este es uno de los estudios científicos, recientemente publicados, que se ha enfocado en registrar la cantidad del compuesto 4-Metilidimazol que se encuentra en las bebidas de Cola y en la cerveza oscura. El compuesto 4-Metilidimazol es un subproducto cancerígeno que se encuentra en el colorante Caramelo IV utilizado en estas bebidas. El estudio reconoce que la mayor ingesta que se da de este compuesto es a través de las bebidas de Cola. Estima que en los Estados Unidos el consumo promedio diario de bebidas de Cola puede representar una ingesta de 342 microgramos diarios de 4-Metilidimazol. Esta cantidad significa varias veces el nivel máximo recomendado como seguro de ingesta de este compuesto sugerido por la autoridad de California, para todo un día que es de 16 microgramos al día. El estudio reporta que una sola lata de bebida de Cola puede contener entre 12.95 y 214.55 microgramos de 4-Metilidimazol.
comprehensive presentation on Detoxification of xenobiotics in human body.This presentation is designed for undergraduate medical ,dental ,biotechnology & pharmacology students for self study.Presentation has Definition of detoxification , classification of toxic substances .Detoxification of endogenous & exogenous toxic substances along with molecular mechanism involved is presented here.Metabolism of xenobiotic (detoxification)
by oxidation. reduction , hydrolysis& conjugation is illustrated with suitable examples.Characteristics of cytochrome P450& its mode of action are described.Google images are used to support the text for better understanding.
1) Novel compounds called O,O-diethyl 1-benzamido-2,2-biscarbamoylethanephosphonates were synthesized as substrates for HIV-1 protease (PR) to exploit activation of the phosphonate group.
2) One compound, O,O-diethyl 1-benzamido-2,2-bis[(1S)-N-(1-benzyl-2-hydroxyethyl)carbamoyl]ethanephosphonate, showed moderate anti-HIV activity in vitro. Its depsipeptide analogue inhibited HIV-1 PR with an IC50 of 31 μM.
3) The phosphonate group of these compounds was designed
Chemical conversion of a substance mediated by living organisms or enzymes
Can result in DETOXIFICATION and BIOACTIVATION
Vital to survive
Key in defense mechanism
Understanding the adsorption mechanisms in nanostructured polymer films has become crucial for their use in technological applications, since film properties vary considerably with the experimental conditions utilized for film fabrication. In this paper, we employ small-angle X-ray
scattering (SAXS) to investigate solutions of polyanilines and correlate the chain conformations with morphological features of the nanostructured films obtained with atomic force microscopy (AFM). It is shown that aggregates formed already in solution affect the film morphology; in
particular, at early stages of adsorption film morphology appears entirely governed by the chain conformation in solution and adsorption of aggregates. We also use SAXS data for modeling poly(o-ethoxyaniline) (POEA) particle shape through an ab initio procedure based on simulated
annealing using the dummy atom model (DAM), which is then compared to the morphological features of POEA films fabricated with distinct pHs and doping acids. Interestingly, when the derivative POEA is doped with p-toluene sulfonic acid (TSA), the resulting films exhibit a fibrillar morphology—seen with atomic force microscopy and transmission electron microscopy—that is consistent with the cylindrical shape inferred from the SAXS data. This is in contrast with the globular morphology observed for POEA films doped with other acids.
The document summarizes the rational design of microbial chemical factories to produce useful compounds. It discusses using metabolic engineering techniques to improve natural producers of compounds like antibiotics and organic acids. Novel pathway design is described using retro-biosynthetic approaches and enzyme selection. Glucaric acid is presented as a model compound produced via a novel 3 step pathway from cloned enzymes. Further optimization using scaffolding to co-localize enzymes increased titer. 3-Hydroxybutyrolactone is also discussed as a target compound currently produced chemically that could potentially be made through a biological pathway.
SiO2@FeSO4 nano composite: A recoverable nano-catalyst for eco-friendly synth...Iranian Chemical Society
Various aldoximes and ketoximes synthesis of corresponding aldehydes and ketones in the presence of SiO2@FeSO4 nano composite as recoverable nano catalyst and NH2OH·HCl. The SiO2@FeSO4 nano composite system was carried out between 10 to 15 min in oil bath (70-80 °C) under solvent-free condition in excellent yields in addition this protocol can be used for industrial scales. This method offers some advantages in term of clean reaction conditions, easy work-up procedure, short reaction time, applied to convert α-diketones to α-diketoximes (as longer than other carbonyl compounds), α,β-unsaturated aldehydes and ketones to corresponding oximes and suppression of any side product. So we think that NH2OH•HCl/SiO2@FeSO4 nano composite system could be considered a new and useful addition to the present methodologies in this area. Structure of products and nano composite elucidation was carried out by 1H NMR, 13C NMR, FT-IR, scanning electron microscopy (SEM).
A Novel Statistical Method for Thermostable Proteins Discrimination IJORCS
This document summarizes a novel statistical method for discriminating between thermostable proteins. The method uses amino acid frequency, dipeptide frequency, and physical-chemical features extracted from protein sequences to classify proteins as mesophilic, thermophilic, or hyper-thermophilic. The researchers tested the effect of each set of features individually and combined on classification accuracy. Their results show the proposed method using all feature types together achieved the best performance, correctly classifying over 90% of proteins on average.
This document reviews drug discovery efforts to develop new antimicrobials by targeting the diaminopimelic acid (DAP) biosynthesis pathway in bacteria. It discusses how DAP is an essential component of bacterial cell walls but not mammalian cells, making enzymes in the DAP pathway potential drug targets. The review focuses on substrate-based inhibitors of DAP pathway enzymes and how understanding the enzymology could aid inhibitor design. Developing inhibitors that selectively block DAP biosynthesis in resistant bacteria could lead to new, less toxic antimicrobial therapies.
This document discusses xenobiotics, or foreign chemicals, and their metabolism in the body. Xenobiotics metabolism mainly occurs in the liver and involves two phases - phase I and phase II reactions. Phase I reactions use enzymes like cytochrome P450 to increase a chemical's water solubility, while phase II reactions further process chemicals through conjugation, such as by adding glucuronic acid or glutathione. Understanding xenobiotic metabolism is important for pharmacology, toxicology, and drug interactions.
This document summarizes the synthesis and characterization of the oxomolybdenum mono-ene-1,2-dithiolate complex (Tp*)MoO(bdtCl2) (3). X-ray crystallography showed compound 3 crystallizes in the monoclinic space group P21/c, with a distorted octahedral coordination geometry around the Mo atom. IR, EPR, and electronic absorption spectroscopy indicate the chlorine substituents do not significantly perturb the electronic structure of the Mo(V) center, but solution redox potentials and gas-phase ionization energies are sensitive to remote substituent effects. The coordination environment of 3 is similar to the related complex (Tp*)MoO(
More detalis abot vitamins and for buying visit at leonutra.com
vitamin cofactors - 5
are vitamins coenzymes - 16
coenzyme vitamins - 7
are vitamins cofactors - 7
what function do many b vitamins serve in the production of energy - 22
which vitamins are coenzymes - 6
coenzymes and vitamins - 7
cofactor vitamin - 5
coenzyme a vitamin - 14
coenzyme a is derived from which of the following vitamins - 8
what vitamin forms a part of coenzyme a - 10
the coenzyme fad is formed from what vitamin - 12
the vitamin that is part of the coenzyme nad is - 11
vitamins and coenzymes - 9
vitamin d coenzyme - 7
does water function as a coenzyme - 15
acetyl coa vitamin - 23
flavin adenine dinucleotide is a coenzyme form of the vitamin - 24
folate coenzymes are needed for the - 18
a cofactor that contains carbon is known as a - 19
how do vitamins help enzymes - 23
which vitamin does not act as a coenzyme - 11
b vitamins act as parts of coenzymes - 12
vitamin c cofactor - 22
vitamins and coenzymes in biochemistry - 15
cofactors for b12 absorption - 17
coenzyme form of vitamin c - 6
coenzymes and vitamins relationship - 5
coenzyme vitamin - 14
coenzyme of vitamin b1 - 13
b12 cofactors - 24
the coenzyme form of riboflavin is - 19
the signs and symptoms of riboflavin deficiency are known collectively as - 24
thiamine cofactor - 17
the vitamin that functions as part of coenzyme a is - 17
vitamins as coenzymes - 14
vitamin k coenzyme - 15
vitamin cofactor - 5
vitamin c coenzyme - 13
vitamins work with enzymes to initiate - 16
vitamins and cofactors - 5
vitamin a coenzyme - 12
mineral cofactors - 14
minerals and vitamins share which characteristic - 26
are b vitamins coenzymes
This document summarizes a study that investigated the degradation of halogenated organic compounds (haloorganics) by iron porphyrin complexes as biomimetic models of marine microbial pathways. The study reacted various iodinated substrates with different iron porphyrin complexes and monitored the reactions using UV-Vis spectroscopy and gas chromatography-mass spectrometry. The results showed that the iodo substrates reacted fastest, followed by chloro and bromo substrates. Products identified included methane, ethylene, and the corresponding dehalogenated alkene. Reaction rates correlated with the redox potential of the iron complex, with higher redox potentials corresponding to faster rates. The study provides insights into abiotic marine degradation of haloorgan
The document describes research on peroxidase enzymes extracted from miswak, a chewing stick made from Salvadora persica roots and stems. Key findings:
- Peroxidase activity was highest in the peel of the stem and root without peel, which is commonly used.
- Three peroxidases (POI, POII, POIII) were separated from root without peel extracts via ion exchange chromatography. POII had the highest activity.
- POII was further purified via gel filtration, found to have a molecular weight of 70 kDa and optimal pH/temperature of 5.5/40°C. It was stable at 10-40°C.
Meulepas, 2010, Effect Of Methanogenic Substrates On Anaerobic Oxidation Of M...roelmeulepas
This document describes a study that tested six methanogenic substrates (acetate, formate, methanol, carbon monoxide, hydrogen, and methanethiol) as potential interspecies electron carriers (IECs) in anaerobic oxidation of methane (AOM) coupled to sulfate reduction. The substrates were added to an enrichment culture containing archaea and bacteria involved in AOM and sulfate reduction. The presence of acetate, formate, hydrogen, and carbon monoxide enhanced sulfate reduction but did not inhibit AOM or trigger methanogenesis. Methanol did not enhance sulfate reduction or inhibit AOM. Methanethiol completely inhibited both AOM and sulfate reduction. Based on these results, the tested substrates could not solely support the electron
This study analyzed changes in the microbial community at different stages of an air sparging bioremediation treatment of soil highly contaminated with jet fuel and BTEX compounds. Microbial community composition and biomass were monitored using phospholipid fatty acid profiling and 16S rRNA gene analysis. Initially, the community was dominated by Pseudomonads under high contamination. As treatment progressed and contaminant levels decreased, biomass and diversity increased. The community shifted to a more complex composition with diverse bacterial taxa, indicating selection pressure from contaminants was reduced as bioremediation succeeded.
Role of ascorbate peroxidase in the antioxidant protectionBilal051
When plants are exposed to stressful environmental conditions, the production of Reactive Oxygen Species (ROS) increases and can cause significant damage to the cells. Antioxidant defenses, which can detoxify ROS, are present in plants. A major hydrogen peroxide detoxifying system in plant cells is the ascorbate-glutathione cycle, in which, ascorbate peroxidase (APX) enzymes play a key role catalyzing the conversion of H2O2 into H2O, using ascorbate as a specific electron donor.
The expression of APX genes is regulated in response to biotic and abiotic stresses as well as during plant development. The APX responses are directly involved in the protection of plant cells against adverse environmental conditions.
Furthermore, mutant plants APX genes showed alterations in growth, physiology and antioxidant metabolism revealing those enzymes involvement in the normal plant development.
This document is a research project report submitted by Rebecca Holmes in partial fulfillment of a BSc in Biochemistry. The report investigates the alkene monooxygenase enzyme from Rhodococcus rhodochrous B-276 which is able to catalyze the stereoselective epoxidation of terminal and subterminal alkenes. Genomic DNA extraction and sequencing was conducted to identify the bacterial strain. SDS-PAGE analysis was unable to detect proteins, suggesting extraction methods need improvement. Propene oxidation assays using different preparation techniques were analyzed by gas chromatography, detecting propene but not epoxypropane. Further research into oxidizing other alkenes using freshly cultured cells could provide valuable chiral epox
COD reduction of aromatic polluted waste water by Advanced Oxidation Process ...Wade Bitaraf
In most petrochemical complexes and oil refineries the wastewater contains the aromatic compounds among which Benzene, Toluene, Ethyl Benzene and Xylene (BTEX) have harmful effects on environment and human health. The present work mainly deals with the UV-based advanced oxidation processes (AOPs), UV/H2O2 were tested in batch reactor systems to evaluate the removal efficiencies and optimal conditions for the photodegradation of BTEX in order to wastewater treatment. The efficiency of this method was analyzed by evaluating the Chemical Oxygen Demand (COD) as a pollution criterion through the COD reactor. The influence of the basic operational parameters such as initial concentration of H2O2, pH, Temperature, irradiation time and UV amount on the photo degradation of BTEX were also studied. The oxidation rate of BTEX and respectively the reduction rate of COD were low when the oxidation was carried out in the absence of H2O2 or UV light. The addition of proper amount of hydrogen peroxide improved the degradation, while the excess hydrogen peroxide could quench the formation of hydroxyl radicals (•OH). The optimal conditions of suspended slurry with 1.11(g/l) initial concentration of H2O2 and pH value of 3.1 were obtained under three UV lights illumination (6 W). Under the optimal conditions, COD reduction during the initial period of 180 min in UV/H2O2 systems reached about 90%.
This document describes research on engineering the methylotroph Methylorubrum extorquens AM1 to produce polyhydroxyalkanoate (PHA) terpolymers with higher compositions of 3-hydroxyvalerate (3HV) and 3-hydroxyhexanoate (3HHx) monomers from methanol. The researchers introduced genes involved in the reverse β-oxidation pathway and ethylmalonyl-CoA decarboxylase to increase precursors for 3HV and 3HHx production. This severely impaired growth on methanol but growth was restored by addition of lanthanum, resulting in a strain that produced PHA terpolymer with 5.4% 3HV and 0.9% 3HHx
1) The document examines the effects of antimycin A and monofluoroacetate treatments on reactive oxygen species (ROS) production and citrate levels in Arabidopsis thaliana leaves.
2) The treatments were found to increase ROS production, as measured by dichloroflourscein diacetate and 3,3-diaminobenzidine. Citrate levels decreased over time with the treatments.
3) Antimycin A treatment led to the highest increase in ROS production and greatest decrease in citrate levels, while monofluoroacetate treatment resulted in lower ROS production and higher citrate levels compared to the control.
This document discusses tropospheric ozone and its ability to trigger similar plant responses as fungal pathogens. It begins by introducing tropospheric ozone and some of the damages it causes plants. It then describes the typical responses plants have to biotic stresses like fungal attacks, such as the hypersensitive response and production of phytoalexins and pathogenesis-related proteins. The document analyzes the biochemistry of ozone stress on plants, noting similarities to responses to pathogens. It concludes by arguing that ozone can act as a fungal elicitor by triggering these same defense responses, and discusses potential applications of this phenomenon in agriculture and plant pathology.
Polyhydroxyalkanoates as an example of natural biodegredable polymers .
PHAs are biodegredable biopolyesters produced by a variety of gram negative and gram positive bacteria.
They have a variety of applications in the industrial and medical fields .
This document discusses an article published in an Elsevier journal about the effects of fruiting body maturity on the antioxidant activity and production of antioxidants in the wild mushroom Lactarius piperatus. Several biochemical assays were used to measure antioxidant properties at different maturity stages: immature, mature with immature spores, mature with mature spores, and degraded. The highest antioxidant contents and lowest values for antioxidant activity assays were found in the mature stage with immature spores. Phenolic, flavonoid, ascorbic acid, beta-carotene and lycopene contents were also determined and correlated with antioxidant activity.
Microorganisms produce two types of biopolymers to survive in extreme conditions: extracellular polysaccharides (EPSs) and endocellular polyhydroxyalkanoates (PHAs). EPSs are high molecular weight polymers biosynthesized by many microorganisms. They can be classified as homopolysaccharides or heteropolysaccharides depending on sugar composition. Microbes secrete EPSs for protective and adaptive functions. Commercial production involves optimizing fermentation conditions to improve yields for applications in pharmaceutical, food, and other industries.
1. Plants are exposed to various stresses from both human activities and natural causes that can increase the production of reactive oxygen species (ROS) in plant tissues.
2. ROS are generated during normal plant metabolic processes and photosynthesis, but stress situations increase their toxic production.
3. Plants have developed complex antioxidant defense systems using enzymatic and non-enzymatic components like ascorbate, glutathione, phenolics and antioxidant enzymes to scavenge ROS and protect against oxidative damage.
Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the environment as a result of incomplete combustion of organic matter. Many PAHs and their epoxides are highly toxic, mutagenic and/or carcinogenic. While various physicochemical methods have been used to remove PAHs, they have limitations. Microorganisms have potential for bioremediation through degradation of PAHs, but their efficiency needs improvement. Research is exploring ways to enhance PAH degradation through metabolic engineering of microorganisms and optimizing factors like bioavailability and chemotaxis.
2006 a novel lipoxygenase in pea roots. its functionAgrin Life
This document summarizes research on a novel lipoxygenase enzyme found in pea roots called LOXN2. Key findings include:
1) LOXN2 was cloned from pea and shown to encode a 93.7 kD protein with two deletions compared to other plant lipoxygenases.
2) When expressed in yeast, LOXN2 exhibited lipoxygenase enzyme activity, preferentially oxygenating linoleic acid to produce both 9- and 13- hydroperoxy octadecadienoic acids in a 3:1 ratio.
3) LOXN2 transcription was found to be downregulated in pea roots infected with the cyst nematode Heterodera goet
2006 a novel lipoxygenase in pea roots. its functionAgrin Life
This document summarizes research on a novel lipoxygenase enzyme found in pea roots called LOXN2. Key findings include:
1) LOXN2 was cloned from pea and shown to encode a 93.7 kD protein with two deletions compared to other plant lipoxygenases.
2) When expressed in yeast, LOXN2 exhibited lipoxygenase enzyme activity, preferentially oxygenating linoleic acid to produce both 9- and 13- hydroperoxy octadecadienoic acids in a 3:1 ratio.
3) LOXN2 transcription was found to be downregulated in pea roots infected with the cyst nematode Heterodera goet
This document summarizes research characterizing the intact 14-subunit respiratory membrane bound [NiFe]-hydrogenase complex (MBH) from the hyperthermophilic archaeon Pyrococcus furiosus. The researchers expressed a His-tagged version of MBH in P. furiosus and purified the intact detergent-solubilized complex using affinity chromatography. The purified MBH complex contained all 14 subunits and exhibited catalytic hydrogen production with physiological electron donors, similar to the membrane-bound form. Small angle X-ray scattering was used to generate a structural model of the purified MBH complex, providing insights into its Z-shaped structure and relationship to other respiratory complexes like Complex I.
This document discusses several topics related to environmental biotechnology, including organic pollution, biodegradation of halogenated hydrocarbons, polycyclic aromatic hydrocarbons, pesticides, and detergents. It provides details on the sources and impacts of persistent organic pollutants. It also describes various microbial and enzymatic pathways used to biodegrade recalcitrant compounds like PAHs, TCE, DDT, and detergents. Microorganisms like Pseudomonas, Nocardia, and fungi play an important role in the aerobic and anaerobic breakdown of these pollutants.
This document summarizes a study that evaluated the effects of nitrogen levels, methanol spraying, and sugar beet varieties on sugar beet yield, yield components, and catalase enzyme activity in two regions of Iran (Karaj and Moghan). The study found that:
1) In Karaj, the highest yield was achieved with the Razor variety without methanol spraying, while in Moghan the highest yield was achieved with the Pars variety and 20% methanol spraying.
2) Nitrogen levels, varieties, methanol spraying, and their interactions significantly affected catalase enzyme activity levels.
3) Proper variety selection and optimizing nitrogen fertilizer and methanol spraying can improve sugar beet yields in both regions.
This document summarizes a study that evaluated the effects of nitrogen levels, methanol spraying, and sugar beet varieties on sugar beet yield, yield components, and catalase enzyme activity in two regions of Iran (Karaj and Moghan). The study found that:
1) In Karaj, the highest yield was achieved with the Razor variety without methanol spraying, while in Moghan the highest yield was achieved with the Pars variety and 20% methanol spraying.
2) Nitrogen levels, varieties, methanol spraying, and their interactions significantly affected catalase enzyme activity levels.
3) Proper variety selection and optimizing nitrogen fertilizer and methanol spraying can improve sugar beet yields in both regions.
Ikan karang merupakan komoditi perikanan dan akuarium yang penting, sehingga diperlukan monitoring berkelanjutan untuk menjaga stoknya. Monitoring dilakukan dengan mengamati perubahan ikan karang setiap tahun karena karakteristiknya yang sedenter, berukuran kecil, mudah diamati, dan hidup di perairan tropis.
Asisten fisiologi tumbuhan 1 asistensi fistum 1Raden Angga
Dokumen tersebut memberikan informasi tentang asistensi Fisiologi Tumbuhan 1, termasuk jadwal, kontak asisten, susunan panitia asistensi, tata tertib praktikum, materi, dan format laporan praktikum.
Alat berat dan alat ringan digunakan dalam berbagai proyek konstruksi. Alat berat meliputi mesin berat seperti buldoser, ekskavator, dan truk tangki, sedangkan alat ringan meliputi peralatan seperti bor, gergaji, dan perkakas tangan lainnya. Gambar dalam dokumen ini menunjukkan berbagai contoh alat berat dan ringan yang digunakan dalam proyek konstruksi.
Dokumen tersebut memberikan informasi tentang filum Echinodermata. Dokumen tersebut menjelaskan ciri khas Echinodermata seperti tubuh lima atau kelipatannya, sistem ambulakral, dan perubahan bentuk tubuh dari simetri bilateral menjadi radial setelah dewasa. Dokumen tersebut juga menjelaskan sistem tubuh, perkembangan, reproduksi, pencernaan, pernafasan, peredaran darah, saraf, dan kelas-kelas utama Echinodermata
Maruthi Prithivirajan, Head of ASEAN & IN Solution Architecture, Neo4j
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Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
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GraphSummit Singapore | The Art of the Possible with Graph - Q2 2024Neo4j
Neha Bajwa, Vice President of Product Marketing, Neo4j
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Driving Business Innovation: Latest Generative AI Advancements & Success StorySafe Software
Are you ready to revolutionize how you handle data? Join us for a webinar where we’ll bring you up to speed with the latest advancements in Generative AI technology and discover how leveraging FME with tools from giants like Google Gemini, Amazon, and Microsoft OpenAI can supercharge your workflow efficiency.
During the hour, we’ll take you through:
Guest Speaker Segment with Hannah Barrington: Dive into the world of dynamic real estate marketing with Hannah, the Marketing Manager at Workspace Group. Hear firsthand how their team generates engaging descriptions for thousands of office units by integrating diverse data sources—from PDF floorplans to web pages—using FME transformers, like OpenAIVisionConnector and AnthropicVisionConnector. This use case will show you how GenAI can streamline content creation for marketing across the board.
Ollama Use Case: Learn how Scenario Specialist Dmitri Bagh has utilized Ollama within FME to input data, create custom models, and enhance security protocols. This segment will include demos to illustrate the full capabilities of FME in AI-driven processes.
Custom AI Models: Discover how to leverage FME to build personalized AI models using your data. Whether it’s populating a model with local data for added security or integrating public AI tools, find out how FME facilitates a versatile and secure approach to AI.
We’ll wrap up with a live Q&A session where you can engage with our experts on your specific use cases, and learn more about optimizing your data workflows with AI.
This webinar is ideal for professionals seeking to harness the power of AI within their data management systems while ensuring high levels of customization and security. Whether you're a novice or an expert, gain actionable insights and strategies to elevate your data processes. Join us to see how FME and AI can revolutionize how you work with data!
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We’ll kick things off by showcasing the most commonly used event-based triggers, introducing you to various automation workflows like manual triggers, schedules, directory watchers, and more. Plus, see how these elements play out in real scenarios.
Whether you’re tweaking your current setup or building from the ground up, this session will arm you with the tools and insights needed to transform your FME usage into a powerhouse of productivity. Join us to discover effective strategies that simplify complex processes, enhancing your productivity and transforming your data management practices with FME. Let’s turn complexity into clarity and make your workspaces work wonders!
Sudheer Mechineni, Head of Application Frameworks, Standard Chartered Bank
Discover how Standard Chartered Bank harnessed the power of Neo4j to transform complex data access challenges into a dynamic, scalable graph database solution. This keynote will cover their journey from initial adoption to deploying a fully automated, enterprise-grade causal cluster, highlighting key strategies for modelling organisational changes and ensuring robust disaster recovery. Learn how these innovations have not only enhanced Standard Chartered Bank’s data infrastructure but also positioned them as pioneers in the banking sector’s adoption of graph technology.
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...Neo4j
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HCL Notes and Domino License Cost Reduction in the World of DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-and-domino-license-cost-reduction-in-the-world-of-dlau/
The introduction of DLAU and the CCB & CCX licensing model caused quite a stir in the HCL community. As a Notes and Domino customer, you may have faced challenges with unexpected user counts and license costs. You probably have questions on how this new licensing approach works and how to benefit from it. Most importantly, you likely have budget constraints and want to save money where possible. Don’t worry, we can help with all of this!
We’ll show you how to fix common misconfigurations that cause higher-than-expected user counts, and how to identify accounts which you can deactivate to save money. There are also frequent patterns that can cause unnecessary cost, like using a person document instead of a mail-in for shared mailboxes. We’ll provide examples and solutions for those as well. And naturally we’ll explain the new licensing model.
Join HCL Ambassador Marc Thomas in this webinar with a special guest appearance from Franz Walder. It will give you the tools and know-how to stay on top of what is going on with Domino licensing. You will be able lower your cost through an optimized configuration and keep it low going forward.
These topics will be covered
- Reducing license cost by finding and fixing misconfigurations and superfluous accounts
- How do CCB and CCX licenses really work?
- Understanding the DLAU tool and how to best utilize it
- Tips for common problem areas, like team mailboxes, functional/test users, etc
- Practical examples and best practices to implement right away
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Spark is the widely used ETL tool for processing, indexing and ingesting data to serving stack for search. Milvus is the production-ready open-source vector database. In this talk we will show how to use Spark to process unstructured data to extract vector representations, and push the vectors to Milvus vector database for search serving.
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Mike Del Balso, CEO & Co-Founder at Tecton, presents "Full RAG," a novel approach to AI recommendation systems, aiming to push beyond the limitations of traditional models through a deep integration of contextual insights and real-time data, leveraging the Retrieval-Augmented Generation architecture. This talk will outline Full RAG's potential to significantly enhance personalization, address engineering challenges such as data management and model training, and introduce data enrichment with reranking as a key solution. Attendees will gain crucial insights into the importance of hyperpersonalization in AI, the capabilities of Full RAG for advanced personalization, and strategies for managing complex data integrations for deploying cutting-edge AI solutions.
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Best 20 SEO Techniques To Improve Website Visibility In SERPPixlogix Infotech
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In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
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In the rapidly evolving landscape of technologies, XML continues to play a vital role in structuring, storing, and transporting data across diverse systems. The recent advancements in artificial intelligence (AI) present new methodologies for enhancing XML development workflows, introducing efficiency, automation, and intelligent capabilities. This presentation will outline the scope and perspective of utilizing AI in XML development. The potential benefits and the possible pitfalls will be highlighted, providing a balanced view of the subject.
We will explore the capabilities of AI in understanding XML markup languages and autonomously creating structured XML content. Additionally, we will examine the capacity of AI to enrich plain text with appropriate XML markup. Practical examples and methodological guidelines will be provided to elucidate how AI can be effectively prompted to interpret and generate accurate XML markup.
Further emphasis will be placed on the role of AI in developing XSLT, or schemas such as XSD and Schematron. We will address the techniques and strategies adopted to create prompts for generating code, explaining code, or refactoring the code, and the results achieved.
The discussion will extend to how AI can be used to transform XML content. In particular, the focus will be on the use of AI XPath extension functions in XSLT, Schematron, Schematron Quick Fixes, or for XML content refactoring.
The presentation aims to deliver a comprehensive overview of AI usage in XML development, providing attendees with the necessary knowledge to make informed decisions. Whether you’re at the early stages of adopting AI or considering integrating it in advanced XML development, this presentation will cover all levels of expertise.
By highlighting the potential advantages and challenges of integrating AI with XML development tools and languages, the presentation seeks to inspire thoughtful conversation around the future of XML development. We’ll not only delve into the technical aspects of AI-powered XML development but also discuss practical implications and possible future directions.
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ARTICLE IN PRESS
Journal of Plant Physiology 167 (2010) 400–407
Contents lists available at ScienceDirect
Journal of Plant Physiology
journal homepage: www.elsevier.de/jplph
Hydrogen peroxide mediates the expression of ascorbate-related genes
in response to methanol stimulation in Oncidium
Chin-Hui Shen, Kai-Wun Yeh n
Institute of Plant Biology, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
a r t i c l e in f o a b s t r a c t
Article history: We investigated the signaling role of hydrogen peroxide (H2O2) in regulating the ascorbate (AsA) level
Received 18 July 2009 after exogenous methanol (MeOH) application. The endogenous H2O2 and AsA levels as well as the
Received in revised form expression of related genes were monitored after MeOH treatment of cultures of Oncidium protocorm-
21 October 2009
like bodies (PLB). A high MeOH concentration was deleterious and caused irreversible consumption of
Accepted 21 October 2009
endogenous AsA. However, a low MeOH concentration (50 mM) triggered the synthesis of H2O2 and
was effective in enhancing the expression of AsA-biosynthetic genes of the Smirnoff–Wheeler and
Keywords: galacturonate (GalUA) pathways. The increased expression of these genes could be blocked by the
Ascorbate addition of hydroxylamine, an inhibitor of alcohol oxidase (EC: 1.1.3.13), and diphenyleneiodonium
Hydrogen peroxide
chloride (DPI), an inhibitor of NADPH oxidase (EC: 1.6.3.1). Thus, the H2O2 generated by MeOH
Methanol
application is a product of MeOH detoxification through alcohol oxidase and NADPH oxidase activation.
In this chain, H2O2 acts as a secondary messenger for the activation of AsA-related genes. Our results
reveal the signaling function of H2O2 and cellular AsA homeostasis in Oncidium orchids in response to
MeOH stimulation. A mechanism for the MeOH effect on AsA production is suggested.
& 2009 Elsevier GmbH. All rights reserved.
Introduction formic acid and CO2 to prevent damage by alcohol oxidase (Gout
et al., 2000). Although the metabolism of MeOH is not completely
Methanol (MeOH) is a volatile organic product, originating understood in plants, its contribution to plant physiology is
from the demethylation of pectin by pectin methylesterase (PME; highlighted by its use in C3 plants for photosynthetic productivity
EC: 3.1.1.11) for tightening of the cell wall, especially throughout (Nonomura and Benson, 1992). Methanol influences C3 plant
the early stage of leaf expansion (Fall and Benson, 1996). Some ´
growth under foliar spray or irrigation (Ramırez et al., 2006), but
MeOH emissions have also been observed during changes in has no effect on C4 plants. Foliar application of MeOH causes an
cell wall construction during the development of roots and fruits increase of fresh and dry weight in Arabidopsis and tobacco,
(Fall and Benson, 1996). Additionally, MeOH might be produced whereas MeOH irrigation significantly delays the growth of
and emitted in large quantities by mechanical wounding or under ´
Arabidopsis, tobacco and tomato (Ramırez et al., 2006). The
˜
various stresses (Fukui and Doskey, 1998; Penuelas et al., 2005; growth promotion by foliar application was ascribed to the
von Dahl et al., 2006; Pelloux et al., 2007). Methanol accumulates increased carbon fixation due to detoxification from photore-
in the intercellular air space or in the liquid pool at night, when spiration. Radiotracer 14C and 13C NMR studies revealed that
the stomata close, and is rapidly converted to formaldehyde, MeOH is metabolized by alcohol oxidase to formaldehyde and
formic acid, which are further converted to serine, methionine,
purine and thymidylate (Gout et al., 2000). The CO2 produced
Abbreviations: AIR, alcohol-insoluble residue; APX, ascorbate peroxidase; AsA, from the oxidization of MeOH is utilized within the Calvin–
ascorbate; D-GalUA, D-galacturonate; DPI, diphenyleneiodonium chloride; GalDH, Benson cycle for glucose metabolism (Hanson and Roje, 2001).
L-galactose dehydrogenase; GalLDH, L-galactono-1,4-lactone dehydrogenase;
Recently, a global gene expression profile resulting from 10%
GalUAR, D-galacturonate reductase; GMP, GDP-D-mannose pyrophosphorylase;
H2DCF-DA, 2,7-dichlorofluorescein diacetate; H2O2, hydrogen peroxide; L-Gal,
MeOH stimulation in Arabidopsis leaves was reported (Downie
L-galactose; L-GalL, L-galactono-1,4-lactone; MDHAR, monodehydroascorbate et al., 2004). Most of the genes induced by MeOH function in
reductase; MeGalUA, methyl-galacturonate; MeOH, methanol; OGA, oligogalac- detoxification and stress responses. After 1 h of MeOH treatment,
turonic acid; PG, polygalacturonase; PLB, protocorm-like body; PME, Pectin the genes with the highest up-regulation are associated with
methylesterase; ROS, reactive oxygen species; SOD, superoxide dismutase
n metabolism, cell communication/signal transduction processes,
Corresponding author. Tel.: + 886 2 33662536; fax: + 886 2 23622703.
E-mail addresses: f92b42021@ntu.edu.tw (C.-H. Shen), ykwbppp@ntu.edu.tw defense, and RNA processing, but none are involved in
(K.-W. Yeh). photosynthesis. At 24- and 72-h MeOH treatment, the genes with
0176-1617/$ - see front matter & 2009 Elsevier GmbH. All rights reserved.
doi:10.1016/j.jplph.2009.10.008
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C.-H. Shen, K.-W. Yeh / Journal of Plant Physiology 167 (2010) 400–407 401
the highest up-regulation are related to anthocyanin and and incubated at 37 1C for 1 h. The amounts of total and reduced
flavonoid metabolism. Additionally, genes encoding detoxification AsA were determined by monitoring the absorbance at 525 nm
proteins, including cytochrome P450s (EC: 1.14.15.6), glucosyl (A525), and the amount of oxidized AsA was calculated from the
transferase (EC: 2.4.1.-) and ascorbate peroxidase (EC: 1.11.1.11), difference between the total pool and the reduced pool.
were induced by MeOH. Altogether, these data revealed that The extraction and measurement of pectin content were
detoxification and signaling pathways are predominantly acti- performed as described (Wang et al., 2008). In brief, Oncidium
vated in plants exposed to methanol. PLB cultures under different treatments were ground in 80%
The modulation of gene expression by chemically inducible ethanol (5 mL/g tissue) and then boiled for 40 min. After being
systems has attracted interest recently for its potential impact on filtered, the residue was washed with 80% ethanol and dried to
both fundamental and applied plant science (Caddick et al., 1998; obtain alcohol-insoluble residues (AIRs). Starch was removed
von Dahl et al., 2006). Although many reports have described from the AIRs by suspension in 90% dimethylsulfoxide for 16 h at
effects of MeOH on metabolism and biochemistry, information on 20 1C and centrifugation at 20,000g for 20 min. The pectic
the regulatory mechanisms of gene expression and MeOH- polysaccharide was extracted from the starch-free AIRs by stirring
induced signal transduction is still limited. in 0.5% ammonium oxalate solution (25 mL/g AIRs) at 80 1C for
Oncidium ‘‘Gower Ramsey’’ is an important orchid in the Asian 1 h, followed by centrifugation at 20,000g for 20 min. The
floral industry. The plant requires more than one year of a supernatant was collected, and ethanol was added at five times
vegetative growth stage to develop a mature pseudobulb to start a the volume of the extract to precipitate pectic polysaccharides.
phase transition. Promotion of the growth rate is a useful strategy The fibrous precipitate was collected by filtration through four
for reducing the cultivation cost. In a survey of chemical layers of miracloth, vacuum dried, and weighed.
stimulants, MeOH was found to be effective in growth promotion The H2O2 level of Oncidium PLB cultures under different
for Oncidium. However, the ambiguity in physiological function treatments was measured as described (Maxwell et al., 1999)
and molecular mechanism is intriguing. The present study of the with some modifications. All experimental steps were performed
ascorbate (AsA) metabolism of the Oncidium orchid revealed that at 4 1C. Oncidium PLB cultures were powdered in liquid nitrogen
the expression of genes involved in the AsA-biosynthetic path- and further homogenized with 100% MeOH. The supernatant was
ways and AsA recycling was affected by MeOH application in PLB obtained from 20 min of centrifugation at 5000g and 4 1C, and
tissues. We determined the optimal concentration of MeOH immediately frozen in liquid nitrogen until further analysis.
effective in activating AsA-related genes and regulating the AsA The samples were thawed to 4 1C, and 2,7-dichlorofluorescein
reduction or oxidation. Our results suggest that H2O2, a byproduct diacetate (H2DCF-DA) was added to the extract at a final
of MeOH oxidation, is a secondary signal in regulating associated concentration of 5 mM. Fluorescence was measured by the use
gene expression in the MeOH-induced network. of a Hitachi F2000 fluorescence spectrophotometer (Tokyo, Japan)
with excitation and emission wavelengths set at 488 nm and
525 nm, respectively.
Materials and methods
Plant materials and chemicals
RT-PCR analysis
Oncidium hybrid ‘‘Gower Ramsey’’ (Oncidium Goldiana x
Oncidium Guinea Gold) was obtained from the Shih–Dong orchid Total RNA for one-step RT-PCR analysis was extracted from
nursery in Taiwan. Oncidium protocorm-like bodies (PLBs) were the Oncidium PLB cultures. One microgram of total RNA was used
cultured in ½ Murashige and Skoog medium (Murashige and as the template in RT-PCR with the following forward and reverse
Skoog, 1962) under long-day conditions (16-h light/8-h dark primers for OgPME (ACJ02103), PME-F-50 -GCTCAAGCTT TGTTCTAT
cycles) at 2372 1C (Liau et al., 2003). L-Galactose (L-Gal), GGT-30 /PME-R-50 -AAAGAAAAAACAAGATAAAATATAGC-30 ; OgPG
D-galacturonate (D-GalUA), methanol (MeOH), diphenyleneiodo-
(A BV24998; EC: 3.2.1.15), PG-F-50 -ACGGCGGTGGCGGCAGAGGA-
nium chloride (DPI) and hydroxylamine were purchased from 30 /PG-R-50 -ACACTG CCCCTGCCCTCTATAGTGCC-30 ; OgGalUAR
Sigma Co. (St. Louis, MO). (ACJ38540; EC: 1.1.-), GalUAR-F-50 -TCC CTGCTTTACAGAAGT
CCCT-30 /GalUAR-R-50 -CCTGGTTTACAAATGGAGGCA-30 ; OgGMP
(FJ618566; EC: 2.7.7.-), GMP-F-50 -TTCGAGCGGCTGCCCGTCCA-30 /
Methanol treatment of PLB cultures and measurement of AsA, H2O2 GMP-R-50 -GGCTGCCCGATGTCCATCCA-30 ; OgGalDH (ACJ38539; EC:
and pectin 1.1.1.122), GalDH-F-50 -TACTCGGAAATTGCCTCCATG-30 /GalDH-R-50 -
CCACACGATCCAAAACATATCTG-30 ; OgGalLDH (ACJ38538; EC:
Treatments of MeOH and L-Gal and D-GalUA were applied to 1.3.2.3), GalLDH-F-50 -TCAAAGAGCACGGGCTTACG-30 /GalLDH-R-50 -
Oncidium PLB cultures, two weeks after subculture from stock AGGGGAAACCTCCATTGTTCC-30 ; OgAPX (FJ237035), APX-F-50 - TG
culture. The extraction and measurement of AsA were performed GCACTCGGCTGGGACTTACGATGT-30 /APX-R-50 -GTGGTCGGAACCTTTG
as described (Gillespie and Ainsworth, 2007) with slight mod- GTAGCATCAGG-30 ; and OgMDHAR (FJ237040), MDHAR-F-50 -AGCA-
ification. Oncidium PLB cultures with different treatments were GACGATGGATCGCT ATCGCCGAA-30 /MDHAR-R-50 -CGAGTTGAGGCGA
homogenized in liquid nitrogen and then mixed well with 1 mL of GTAGAGCACGTTGA-30 . A one-step RT-PCR kit was used for processing
6% trichloroacetic acid. After centrifugation at 4 1C and 6000g for of all the samples (Takara, Japan). The template was reverse-
15 min, the resultant supernatant acted as a reactant for assays of transcribed at 50 1C for 30 min and denatured at 94 1C for 2 min,
total, reduced and oxidized AsA levels. For the total AsA assay, the followed by 12 cycles for OgPG, OgGalDH, OgGalLDH, OgAPX,
reactant was mixed with 10 mM dithiothreitol to reduce the pool OgMDHAR and 18S rRNA amplification; 15 cycles for OgPME and
of oxidized AsA. After being incubated at room temperature for OgGalUAR amplification; and 20 cycles for OgGMP for amplification
10 min, the mixture was supplemented with 0.5% N-ethylmalei- (one cycle consisted of 94 1C for 30 s for denaturation, 47–66 1C for
mide to remove the excess dithiothreitol. By contrast, to assay 30 s for annealing depending on the genes, and 72 1C for 30 s for
reduced AsA, only deionized water was added to the reactant. elongation) and extension at 72 1C for 10 min. As a control, the RT-
All mixtures were supplemented with reaction buffer (10% PCR reaction was performed for 18S rRNA with specific primers as
trichloroacetic acid, 43% H3PO4, 4% a–a0 -bipyridyl and 3% FeCl3) described above.
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Enzyme assays was determined from the decrease in A290 by the oxidation of AsA.
One unit of APX was defined as the activity that consumed 1 mmol
The activities of PG, PME, GalUAR, GMP, GalDH, GalLDH and AsA min À 1 mg À 1 total protein. For SOD activity, the crude protein
APX were assayed following the method described by Shen et al. was mixed with reaction buffer (100 mM triethanolamine–
(2009). The activities of MDHAR and superoxide dismutase (SOD; diethanolamine, 7.5 mM NADH, 100 mM EDTA, 50 mM MnCl2,
EC: 1.15.1.1) were measured following modified methods of pH 7.4). The SOD activity was determined from the decrease in
Eltayeb et al. (2007) and Paoletti et al. (1986), respectively. A340 by the oxidation of NADH. One unit of SOD was defined as the
Oncidium PLB cultures for the PME activity assay were ground in activity that consumed 1 mmol NADH min À 1 mg À 1 total protein.
extraction buffer (0.1 M citrate, 0.1 M sodium citrate, 1 M
Na2HPO4 and 1 M NaCl, pH 5.0), those for PG activity assay were
ground in extraction buffer (1 M NaCl, and 0.2 M Na2HPO4 in 1 M Results
citrate buffer, pH 4.0) and those for the APX activity assays were
ground in extraction buffer (2.5 mL of 25 mM potassium phos- Exogenous application of methanol stimulates AsA biosynthesis in
phate buffer, pH 7.8) containing 2% polyvinylpolypyrrolidone, Oncidium PLB cultures
0.4 mM EDTA and 1 mM AsA. For the other activity assays, the
pseudobulbs were ground in extraction buffer (50 mM sodium To study the effect of the MeOH dosage on AsA biosynthesis
phosphate buffer, pH 7.2, 2 mM EDTA, 2 mM dithiothreitol, 20% in Oncidium, 10–500 mM MeOH was applied exogenously to
glycerol and 2% polyvinylpolypyrrolidone. After centrifugation for Oncidium PLB culture. The endogenous AsA level in tissues was
30 min at 4 1C at 6000g, the resultant supernatant was used as the measured at 6, 12, 24 and 30 h after MeOH application. As shown
crude enzyme. For the PME assay, the crude protein was mixed in Fig. 1A, application of MeOH resulted in varied AsA levels in the
with reaction buffer (0.1% esterified pectin in 0.2 M Na2HPO4 PLB cultures. In general, the AsA level preferentially decreased
buffer, pH 6.3). After overnight incubation at 37 1C, 0.05% during the first 6 h of incubation, then showed an irreversible
ruthenium red was added and mixed before incubation for response to various concentrations of MeOH. Notably, the PLB
10 min. Next, 0.6 M CaCl2 was added to precipitate the demethy- culture was lethally affected by 500 mM MeOH (Fig. 1B), and the
lated pectin. The mixture was centrifuged at 14,000g for 15 min to AsA level was markedly decreased. Upon treatment with 50 mM
remove the precipitate. The absorbances at 534 nm (A534) of the MeOH, the AsA level of the Oncidium PLB culture increased
supernatants of the samples were measured. For the PG assay, the following 24 h of inoculation. Thus, a 50 mM MeOH concentration
crude protein was mixed with reaction buffer (1% cyanoacetamide was concluded to be appropriate for signaling AsA biosynthesis in
in 0.1 M borate buffer, pH 7.0) for 5 min. The PG activity was Oncidium.
determined from the increase in A276 of 2-cyanoacetamide by the
production of galacturonic acid. One unit of PG was defined as the
Characterization of AsA induction by MeOH stimulation
activity that produced 1 mmol of galacturonic acid min À 1 g À 1 FW.
For the GalUAR assay, the crude protein was mixed with reaction
To unravel the mechanism of AsA induction after 50 mM
buffer (0.1 mM NADPH and 0.1 mM galacturonic acid in 50 mM
MeOH stimulation, several AsA-inducing compounds (Davey
sodium phosphate buffer, pH 7.2) for 1 min. The GalUAR activity
et al., 1999), such as D-galacturonate (D-GalUA) and L-galactose
was determined from the increase in A254 by the production of
(L-Gal), were applied to the PLB culture and their effects were
NADP + . One unit of GalUA reductase was defined as the activity
compared (Fig. 2A and B). The AsA levels in the PLB culture
that oxidized 1 mM NADPH min À 1 mg À 1 total protein. For the
increased by MeOH (50 mM), D-GalUA (50 mM), and L-Gal
GMP assay, the crude protein was mixed with reaction buffer
(50 mM) treatment (Fig. 2A); however, treatment of MeOH
(1 mM MgCl2, 0.4 mM glucose, 0.1 mM ADP, 0.1 mM GDP-
alone significantly decreased the AsA level during the first 6 h of
mannose in 50 mM Tris–HCl buffer, pH 7.0). The reaction was
inoculation. Interestingly, assays of the AsA redox state (reduced
started by serially adding 12 U of hexokinase, 3 U of glucose-
form AsA/oxidized form AsA) in the PLB culture showed a similar
6-phosphate dehydrogenase and 1 mM sodium pyrophosphate.
pattern to that of AsA level (Fig. 2B). The distinct variation of the
The GMP activity was monitored by measuring the A340 to
AsA profile with MeOH application suggests that MeOH is
monitor the formation of NADH. One unit of GMP was defined as
deleterious to Oncidium cells. The level of H2O2 significantly
that which reduced 1 mM NAD + min À 1 mg À 1 total protein. For the
increased from 27.8 to 39.1 mM with MeOH application during the
GalDH assay, the crude protein was mixed with reaction buffer
first 6 h of treatment (Table 1), whereas no significant effects
(0.1 mM NAD + and 0.15 mM L-galactose in 50 mM sodium
were observed by the other chemicals, such as L-Gal and D-GalUA.
phosphate buffer, pH 7.2). The GalDH activity was determined
Detoxification of MeOH during the first 6 h of treatment is
from the increase in A340 by the formation of NADH. One unit of
important for the up-regulation of AsA-related genes. Moreover,
GalDH was defined as the activity that reduced 1 nM NAD +
MeOH has a distinct effect of H2O2 generation when applying to
min À 1 mg À 1 total protein. For the GalLDH assay, the crude
Oncidium culture.
protein was mixed with reaction buffer (0.2% cytochrome c and
4.2 mM L-galactono-1,4-lactone in 0.01 M potassium phosphate
buffer, pH 7.8). The GalLDH activity was determined from the Methanol enhances AsA levels by up-regulating AsA-biosynthesis and
increase in A550 by the reduction of cytochrome c. One unit of defense genes
GalLDH was defined as the activity that oxidized 1 mmol of L-
galactono-1,4-lactone min À 1 mg À 1 total protein. For MDHAR Since the application of 50 mM MeOH to Oncidium PLB culture
activity, the crude protein was mixed with reaction buffer was effective in elevating the AsA level (Fig. 2A), we investigated
(0.1 M Tris–HCl pH 7.2, 0.2 mM NADH, 2 mM AsA, 1 U AsA the effect of 50 mM MeOH on the expression level of AsA-
oxidase). The MDHAR activity was determined from the decrease biosynthetic genes in the GalUA pathway, such as polygalactur-
in A340 by the oxidization of NADH. One unit of MDHAR was onase (OgPG), pectin methylesterase (OgPME) and galacturonate
defined as the activity that oxidized 1 nmol NADH min À 1 mg À 1 reductase (OgGalUAR), as well as those in the Smirnoff–Wheeler
total protein. For APX activity, the crude protein was mixed with pathway, such as GDP-D-mannose pyrophosphorylase (OgGMP)
reaction buffer (25 mM potassium phosphate buffer, pH 7.0, and galactose dehydrogenase (OgGalDH). The RT-PCR data showed
0.25 mM AsA, 0.4 mM EDTA and 0.1 mM H2O2). The APX activity that OgPG and OgPME, which are involved in pectin degradation,
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0.5 50 mM
½ MS
MeOH
50 mM MeOH
0.4 ½MS
10 mM MeOH
µmole AsA /g F.W.
100 mM MeOH
0.3
500 mM
0.2 MeOH
500 mM MeOH
0.1
2mm
0
0 10 20 30
Time (hours)
Fig. 1. (A) Effect of methanol (MeOH) doses on ascorbate (AsA) level in Oncidium protocorm-like body (PLB) cultures. Oncidium PLB cultures were incubated with 500 mM
(m), 100 mM (B), 50 mM (J), and 10 mM (&) MeOH and 1/2 MS medium as a control (W) for 30 h. Vertical bars represent standard deviation of the mean obtained from
three independent experiments. (B) The PLB culture markedly varied with MeOH dosage, with 500 mM MeOH being lethal to Oncidium PLB culture, and 50 mM having no
effects. All Oncidium PLB cultures were photographed after 12 h treatment.
0.55 12.00
50 mM L-Gal
50 mM D-GalUA +
0.50 50 mM D-GalUA + 10.00 50 mM MeOH
50 mM MeOH 50 mM L-Gal
0.45
µmole AsA/g F.W.
AsA Redox ratio
50 mM D-GalUA
50 mM MeOH
8.00 50 mM D-GalUA
50 mM MeOH
0.40 CK (½ MS)
CK (½ MS)
6.00
0.35
4.00
0.30
2.00
0.25
0.20 0.00
0 6 12 18 24 30 0 6 12 18 24 30
Time (hours) Time (hours)
Fig. 2. The AsA level and redox state in Oncidium PLB cultures incubated with various compounds for 30 h. (A) AsA level, (B) AsA redox ratio. Vertical bars represent
standard deviations of the means obtained from three independent experiments. 50 mM MeOH (&), 50 mM D-galacturonate (D-GalUA) (B), 50 mM MeOH and 50 mM
D-GalUA (W), 50 mM L-galactose (L-Gal) (J) and 1/2 MS (m).
were both up-regulated after 6 h of MeOH treatment. However, To further understand the proteins associated with the AsA-
the expression of OgPME was decreased at 24 h. In contrast, related genes under 50 mM MeOH stimulation, their enzymatic
no further changes in the expression level of OgGalUAR by MeOH activities were assayed. As shown in Fig. 4, the activities of OgPG,
treatment were observed (Fig. 3). On the other hand, both OgGMP OgMDHAR, OgAPX and OgSOD were specifically enhanced from 6
and OgGalDH of the Smirnoff–Wheeler pathway were up- to 12 h upon MeOH treatment, whereas other enzymes, such as
regulated during the first 6 h of MeOH treatment, effects OgGalUAR, OgGMP, OgGalDH, OgGalLDH, were not significantly
lasting for 30 h (Fig. 3). This is similar to the effect by L-Gal enhanced by MeOH stimulation, even though they were enhanced
stimulation, which acts as a carbon source, similar to D-GalUA in RNA levels. These results indicated that mRNA levels of many of
in AsA-biosynthetic routes (Fig. 3; Davey et al., 1999). Finally, these genes are not correlated with enzymatic activities, which
the expression of galactono-1,4-lactone dehydrogenase may be related to post-translational modifications.
(OgGalLDH), an integrator of the AsA biosynthetic pathway, The pectin content of the Oncidium PLB culture was decreased
displayed an enhanced level upon MeOH treatment (Fig. 3). In in 50 mM MeOH treatment, but not in L-Gal or D-GalUA treatment
addition, the levels of defense genes, including ascorbate (Table 1). The degradation appeared to result mainly from the
peroxidase (OgAPX) and monodehydroascorbate reductase elevated activity of OgPG under MeOH stimulation (Fig. 4). In
(OgMDHAR), were also increased at 6–24 h after MeOH conclusion, the AsA level was elevated in Oncidium PLB culture by
treatment (Fig. 3). Taken together, a 50 mM MeOH treatment MeOH stimulation, primarily because of the enhanced expression
was effective to enhance the expression level of most AsA-related level and enzymatic activity of OgPG. Although the mRNA levels
genes in the GalUA pathway, Smirnoff–Wheeler pathway and of a number of AsA-biosynthetic genes were certainly induced
defense system. and enhanced, their functional contribution in AsA biosynthesis is
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404 C.-H. Shen, K.-W. Yeh / Journal of Plant Physiology 167 (2010) 400–407
unclear due to the absence of increased enzymatic activity with elevated from 27.8 to 39.1 mM in Oncidium PLB cultures in
MeOH treatment. response to exogenous application of MeOH, but not D-GalUA and
L-Gal, during the first 6 h of treatment (Table 1). To unravel the
source of H2O2 production, we applied hydroxylamine (1 mM)
Hydrogen peroxide production in Oncidium PLB cultures through the and DPI (5 mM), inhibitors of alcohol oxidase and NADPH oxidase,
activation of alcohol oxidase and NADPH oxidase under MeOH respectively, with MeOH in PLB cultures, and monitored the H2O2
stimulation levels. In Oncidium PLB cultures incubated with 50 mM MeOH, an
early H2O2 burst ( $45 mM) was detected during the first 30 min,
Plant cells are able to convert MeOH to formaldehyde and followed by a subsequent decrease in accumulation ( $40 mM)
H2O2 by alcohol oxidase (Gout et al., 2000). The H2O2 level was that lasted for another 6 h (Fig. 5). However, this H2O2 burst
was attenuated by incubation with 50 mM MeOH combined
Table 1 with 1 mM hydroxylamine or 5 mM DPI. The DPI inhibitor was
H2O2 amount and pectin concentration of PLBs incubated with various treatments. more effective in blocking H2O2 generation than the alcohol
oxidase inhibitor. NADPH oxidase could play a more significant
Treatments (h) H2O2 (mM) Pectin (mg/g F.W.)
role in the systemic production of H2O2 than alcohol oxidase does.
CK (1/2 MS) Therefore, the stimulation of the H2O2 level by MeOH in the
0 28.2972.83 31.46 7 0.64 Oncidium culture occurs directly, through MeOH metabolism (or
6 28.5771.98 32.20 7 0.93 detoxification) by alcohol oxidase activity, and indirectly, through
12 28.92 71.73 30.85 7 1.13 the subsequent induction of NADPH oxidase activity to amplify
24 26.50 71.24 31.65 7 1.67
30 28.68 72.32 30.45 7 1.01
H2O2 production. Moreover, the early oxidative peak of the H2O2
50 mM L-Gal level in the Oncidium culture could be largely due to the
0 28.1272.44 31.21 7 1.03 conversion of MeOH by alcohol oxidase, and the later H2O2
6 28.39 72.58 30.70 7 0.55 burst could result primarily from NADPH oxidase activation
12 28.35 71.33 29.98 7 0.51
(Fig. 5).
24 30.007 1.42 30.13 7 0.57
30 28.38 72.32 30.88 7 0.58
50 mM D-GalUA
0 26.8672.81 30.09 7 0.56
The up-regulation of AsA-related genes stimulated by MeOH is
6 28.75 71.85 30.07 7 0.56
12 28.85 72.15 30.56 7 0.93
through H2O2 signal transduction
24 27.47 72.72 31.43 7 1.16
30 27.73 71.89 30.95 7 0.16 To confirm the potential signaling effects of H2O2 on the
50 mM MeOH
expression of AsA-related genes, we investigated the expression
0 27.75 71.72 30.92 7 0.58
6 39.14 71.28 26.42 7 0.96
of AsA-related genes under the application of the inhibitors alone
12 33.14 71.52 25.65 7 0.58 or with MeOH. As shown in Fig. 6, the expression of AsA-related
24 31.43 71.30 26.02 7 1.45 genes did not change after 6 h with 1 mM hydroxylamine
30 30.74 71.61 27.57 7 1.00 or 5 mM DPI treatment. However, the expressional levels of
50 mM D-GalUA+ 50 mM MeOH
AsA-related genes were lower with MeOH combined with
0 29.03 72.09 30.86 7 0.16
6 40.11 71.28 26.84 7 0.99 hydroxylamine or DPI than with MeOH alone. Hydroxylamine
12 34.6171.05 25.48 7 1.14 and DPI inhibited H2O2 production (Fig. 5), consequently reducing
24 32.46 72.89 26.94 7 1.58 the MeOH effect on the expression of AsA-related genes in
30 28.82 70.98 27.35 7 0.43 Oncidium PLB cultures (Fig. 6). The results suggest that H2O2
PLBs= protocorm-like bodies; F.W.= fresh weight. Mean values7 S.E. were
signaling is critical in up-regulating the expression of AsA-related
obtained from three independent experiments. genes.
50 mM
D-GalUA
50 mM 50 mM +
GalUA pathway CK D-GalUA 50 mM MeOH 50 mM MeOH
L-Gal
Pectin 0 6 12 24 30 0 6 12 24 30 0 6 12 24 30 0 6 12 24 30 0 6 12 24 30h
OgPG
MeGalUA OgPME
OgGalUAR
D-GalUA
OgGMP
Smirnoff-Wheeler
pathway
OgGalDH
D-Glc-6-P
L-GalA
OgGalLDH
D-Man-1-P OgMDHAR
GDP- D-Man
OgAPX
L-Gal
L-GalL 18S rRNA
Ascorbate MDHA
H2O2
H 2O
AsA recycling
Fig. 3. Expression of AsA-related genes on treatment of Oncidium PLB cultures with various compounds. The relative amount of transcripts of OgPME, OgPG and OgGalUAR
in the GalUA pathway; OgGMP, OgGalDH and OgGalLDH in the Smirnoff–Wheeler pathway and OgAPX and OgMDHAR in the defense system were determined by RT-PCR.
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60 1 OgPG
7
2 OgPME
1 8
3 OgGalUAR 1
50 4 OgGMP
7
5 OgGalDH 8
6 OgGalLDH
40 7 OgMDHAR
Activity Unit
8 OgAPX
9 OgSOD
30
8 9 9
1 5 5
20 4
2 5 4
2
7 3 4
3
2 6 9 6 6
3
10
0
0 6 12
Time (hours)
Fig. 4. Activity assays of AsA-related enzymes under 50 mM MeOH treatments. Activity units of AsA-related enzymes were defined in Materials and methods, and vertical
bars represent standard deviations of the means obtained from three independent experiments.
50.00
45.00
40.00
50 mM MeOH
µM H2O2
50 mM MeOH + 1 mM hydroxylamine
35.00
30.00
50 mM MeOH + 5 mM DPI
½ MS + 1 mM hydroxylamine
25.00 ½ MS + 5 mM DPI
CK (½ MS)
20.00
0 1 2 3 4 5 6
Time (hours)
Fig. 5. The effects of hydroxylamine (inhibitor of alcohol oxidase) and diphenyleneiodonium chloride (DPI; inhibitor of NADPH oxidase) on H2O2 production in Oncidium
PLB cultures for 6 h. Vertical bars represent standard deviations of the means obtained from three independent experiments.
Discussion (Fig. 3). Moreover, the H2O2 level was elevated after 30 min
treatment and maintained for at least 6 h (Fig. 5). By adding
Methanol (MeOH) is known as a deleterious by-product hydroxylamine or DPI compounds with MeOH into the Oncidium
derived from pectin demethylation during the cell wall recon- PLB cultures, the activities of alcohol oxidase and NADPH oxidase
struction process in plants. Its effects on plant growth in Vigna were inhibited. Accordingly, H2O2 production was markedly
radiata were reported 20 years ago (Bhattacharya et al., 1985). decreased in PLB cultures by 8 to 20% (Fig. 5). In addition, NADPH
Although the effects of MeOH on plant physiology and gene oxidase was more effective than alcohol oxidase in producing
expression have been investigated (Gout et al., 2000; Galbally and H2O2, because the inhibition of NADPH oxidase activity by DPI had
Kirstine, 2002; Downie et al., 2004), its mechanism of signal a greater effect on the H2O2 level ( À20%) than inhibition of
transduction mechanism has not been elucidated. As previously alcohol oxidase activity ( À 8%) (Fig. 5). Thus, the H2O2 level was
reported in Arabidopsis, AsA-biosynthetic genes in the Smirnoff– enhanced by MeOH stimulation through two steps: MeOH
Wheeler pathway and AsA-recycling and pectin degradation oxidation by alcohol oxidase and systemic amplification by
genes were all stimulated by an appropriate concentration of NADPH oxidase. In addition, the diminished H2O2 level with
´
MeOH (Downie et al., 2004; Ramırez et al., 2006), but genes inhibition of alcohol oxidase and NADPH oxidase caused a reduced
related to photosynthesis were not responsive to MeOH expression of AsA-related genes (Fig. 6). In conclusion, the results
application (Downie et al., 2004). strongly suggest that H2O2 acts as a signaling messenger to
In the present study, exogenous application of MeOH (50 mM) regulate AsA-related gene expression under MeOH stimulation.
to Oncidium PLB cultures increased the AsA level by 30% (Figs. 1 Hydrogen peroxide is a reactive oxygen species (ROS)
and 2) and AsA-related genes were markedly up-regulated produced by plants under stress conditions (Mittler et al., 2004).
8. Author's personal copy
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406 C.-H. Shen, K.-W. Yeh / Journal of Plant Physiology 167 (2010) 400–407
50 mM MeOH 50 mM MeOH
+ +
1 mM 5 mM 50 mM 1 mM 5 mM
GalUA pathway CK hydroxylamine DPI MeOH hydroxylamine DPI
Pectin 0 2 6 0 2 6 0 2 6 0 2 6 0 2 6 0 2 6 h
OgPG
MeGalUA OgPME
OgGalUAR
D-GalUA
Smirnoff-Wheeler OgGMP
pathway
OgGalDH
L-GalA D-Glc-6-P
OgGalLDH
D-Man-1-P OgMDHAR
GDP- D-Man
OgAPX
L-Gal
L-GalL 18S rRNA
Ascorbate MDHA
H2O2
H2O
AsA recycling
Fig. 6. Expression of AsA-related genes on treatment with H2O2-producing inhibitors. Total RNA was isolated from PLBs incubated with hydroxylamine or DPI. The relative
amount of transcripts for OgPME, OgPG and OgGalUAR in the GalUA pathway; OgGMP, OgGalDH and OgGalLDH in the Smirnoff–Wheeler pathway; and OgAPX and OgMDHAR
in the defense system were determined by RT-PCR.
Pectin
PG
PME
MeOH + OGA + D-GalUA
alcohol
formaldehyde oxidase
formate H2O2
GalUA pathway
PM NADPH Oxidase
Calvin-Benson cycle
H2O2
Defense genes (APX,MDHAR, etc)
Smirnoff-Wheeler pathway
AsA
GalUA pathway (pectin degrad. -PG,PME)
Fig. 7. The proposed model of the H2O2-signaling network under MeOH stimulation in Oncidium PLB cultures. Methanol is produced along with oligogalacturonic acid
(OGA) and D-GalUA during the degradation of pectin in the plant cell wall. Methanol is preferentially oxidized (detoxified) by alcohol oxidase to H2O2 and formaldehyde.
Subsequently, H2O2 activates NADPH oxidase to create more H2O2, which acts as secondary messenger to induce the expression of AsA-related biosynthetic genes.
In addition, OGA also enhances H2O2 production (Ridley et al., 2001). D-GalUA might be a precursor for AsA synthesis in the GalUA pathway. The products of pectin
degradation involved in H2O2 signal transduction could function in elevating AsA levels in cells. A high AsA level could scavenge reactive oxygen species and protect the cell
from stresses. APX =ascorbate peroxidase; MDHAR= monodehydroascorbate reductase.
Induced H2O2 can act as a local signal for hypersensitive cell death 2009). The enzymatic activities (but not the mRNA levels)
and as a diffusible signal for the induction of defense genes in of some AsA-biosynthetic genes, such as OgGMP, OgGalDH,
adjacent cells (Alvarez et al., 1998). The functional roles are OgGalLDH and OgGalUAR, were not enhanced by MeOH stimula-
complicated and diversified. Therefore, the induction of the plant tion, indicating regulation based on post-translational modifica-
defense system is tightly controlled for its production and tions. However, the AsA level is eventually increased in response
scavenging. In several model systems of plants, the oxidative to MeOH. These enzymatic activities are not critical for AsA
burst and accumulation of H2O2 appear to be mediated by the synthesis in AsA-biosynthetic pathway experiencing the effects of
activation of a membrane-bound NADPH oxidase complex (Zhang MeOH. On the other hand, the increased activity of OgPG is
¨
et al., 2007; Konigshofer et al., 2008; Wen et al., 2008). In the necessary for AsA production as well as the oligogalacturonic acid
Oncidium system, H2O2 induction has been identified as a signal to (OGA) product, a ligand to induce H2O2 generation after MeOH
induce AsA-related genes during vegetative growth (Shen et al., treatment. In addition, AsA-recycling enzymes, OgAPX and
9. Author's personal copy
ARTICLE IN PRESS
C.-H. Shen, K.-W. Yeh / Journal of Plant Physiology 167 (2010) 400–407 407
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The authors are grateful to the National Science Council, lacturonide-related signaling. Phytochemistry 2001;57:929–967.
Shen CH, Krishnamurthy R, Yeh KW. Decreased L-ascorbate content mediating
Taiwan, for financial support granted to Dr. Kai-Wun Yeh under bolting is mainly regulated by the galacturonate pathway in Oncidium. Plant
the project NSC-95-2317-B-002-005. The authors also thank Dr. Cell Physiol 2009;50:935–946.
Ching-Huei Kao, Department of Agronomy, National Taiwan Smirnoff N. Vitamin C booster. Nat Biotechnol 2003;21:134–136.
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and Dr. Chao-Ying Chen, Department of Plant Pathology and 948–960.
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