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Готові списки джерел за темами / Enzyme de modification des pectines

Добірка наукової літератури з теми "Enzyme de modification des pectines"

Автор: Grafiati

Опубліковано: 18 жовтня 2022

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Статті в журналах з теми "Enzyme de modification des pectines":

1

Kim, Yu-Jin, Ho Young Jeong, Seung-Yeon Kang, Jeniffer Silva, Eui-Jung Kim, Soon Ki Park, Ki-Hong Jung, and Chanhui Lee. "Physiological Importance of Pectin Modifying Genes During Rice Pollen Development." International Journal of Molecular Sciences 21, no. 14 (July 8, 2020): 4840. http://dx.doi.org/10.3390/ijms21144840.

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Although cell wall dynamics, particularly modification of homogalacturonan (HGA, a major component of pectin) during pollen tube growth, have been extensively studied in dicot plants, little is known about how modification of the pollen tube cell wall regulates growth in monocot plants. In this study, we assessed the role of HGA modification during elongation of the rice pollen tube by adding a pectin methylesterase (PME) enzyme or a PME-inhibiting catechin extract (Polyphenon 60) to in vitro germination medium. Both treatments led to a severe decrease in the pollen germination rate and elongation. Furthermore, using monoclonal antibodies toward methyl-esterified and de-esterified HGA epitopes, it was found that exogenous treatment of PME and Polyphenon 60 resulted in the disruption of the distribution patterns of low- and high-methylesterified pectins upon pollen germination and during pollen tube elongation. Eleven PMEs and 13 PME inhibitors (PMEIs) were identified by publicly available transcriptome datasets and their specific expression was validated by qRT-PCR. Enzyme activity assays and subcellular localization using a heterologous expression system in tobacco leaves demonstrated that some of the pollen-specific PMEs and PMEIs possessed distinct enzymatic activities and targeted either the cell wall or other compartments. Taken together, our findings are the first line of evidence showing the essentiality of HGA methyl-esterification status during the germination and elongation of pollen tubes in rice, which is primarily governed by the fine-tuning of PME and PMEI activities.

2

Seghini, Maria Carolina, Jacopo Tirillò, Maria Paola Bracciale, Fabienne Touchard, Laurence Chocinski-Arnault, Antonio Zuorro, Roberto Lavecchia, and Fabrizio Sarasini. "Surface Modification of Flax Yarns by Enzymatic Treatment and Their Interfacial Adhesion with Thermoset Matrices." Applied Sciences 10, no. 8 (April 23, 2020): 2910. http://dx.doi.org/10.3390/app10082910.

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The aim of this study was to assess the effects of commercially available and relatively inexpensive enzyme preparations based on endo 1,4-β-xylanase, pectinase and xyloglucanase on the thermal (TGA), morphological (SEM), chemical (FT-IR) and mechanical (single yarn tensile tests) properties of flax yarns. The preparation based on pectinase and xyloglucanase provided the best results, resulting in the effective removal of hydrophilic components such as hemicellulose and pectin, the individualization of yarns and increased thermal stability at the expense of a reduction in mechanical properties, depending on the treatment parameters. Single yarn fragmentation tests pointed out an improved interfacial adhesion after enzymatic treatment, with reduced debonding length values of 18% for an epoxy matrix and up to 36% for a vinylester resin compared to untreated flax yarns.

3

Muñoz-Blandón, Oscar, Margarita Ramírez-Carmona, Beatriz Cuartas-Uribe, and José Antonio Mendoza-Roca. "Evaluation of Original and Enzyme-Modified Fique Fibers as an Azo Dye Biosorbent Material." Water 14, no. 7 (March 25, 2022): 1035. http://dx.doi.org/10.3390/w14071035.

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As natural fibers, low-cost biosorbents have proven to be an effective and clean tool to remove textile dyes from wastewater. In this research, the Reactive Black 5 removal ability of original and enzyme-modified natural fibers were assessed. A fiber extracted from a Colombian fique plant (Furcraea sp.) was employed. The effects of fique fiber protonation with different solvents and dye solution pH on RB5 removal were evaluated. The biosorbent chemical composition was modified using the commercial enzymes pectinase, ligninase, and xylanase. The point of zero charge (PZC) of the original and modified material was measured, and the dye removal capacity of the three enzyme-modified fibers was determined. Fiber protonation with 0.1 M HCl and a dye solution with pH of 2.4 increased the RB5 elimination to 49.1%. The change in the fiber chemical composition led to a reduction in the PZC from 5.5 to a 4.7–4.9 range. Pectinase-pretreated fique fibers presented the highest dye removal of 66.29%, representing a 36% increase in RB5 dye removal. Although the original fique fiber showed RB5 dye removal ability, its enzymatic modification changed the charge distribution on the fiber surface, improving the capture of dye molecules. Enzyme modification can be applied to obtain new functionalities for plant fibers as biosorbent materials.

4

Morais, Patrícia Lígia Dantas de, Luiz Carlos de Oliveira Lima, Maria Raquel Alcântara de Miranda, José Donizete Alves, Ricardo Elesbão Alves, and José Daniel Silva. "Enzyme activities and pectin breakdown of sapodilla submitted to 1-methylcyclopropene." Pesquisa Agropecuária Brasileira 43, no. 1 (January 2008): 15–20. http://dx.doi.org/10.1590/s0100-204x2008000100003.

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The objective of this work was to investigate the influence of 1-methylcyclopropene (1-MCP) at 300 nL L-1 on activities of cell wall hidrolytic enzymes and pectin breakdown changes which Sapodilla (Manilkara zapota cv. Itapirema 31) cell wall undergoes during ripening. Sapodilla were treated with ethylene antagonist 1-MCP at 300 nL L-1 for 12 hours and then, stored under a modified atmosphere at 25º C for 23 days. Firmness, total and soluble pectin and cell wall enzymes were monitored during storage. 1-MCP at 300 nL L-1 for 12 hours delayed significantly softening of sapodilla for 11 days at 25º C. 1-MCP postharvest treatment affected the activities of cell wall degrading enzymes pectinmethylesterase and polygalacturonase and completely suppressed increases in beta-galactosidase for 8 days, resulting in less pectin solubilization. Beta-galactosidase seems relevant to softening of sapodilla and is probably responsible for modification of both pectin and xyloglucan-cellulose microfibril network.

5

Shin, Yesol, Andrea Chane, Minjung Jung, and Yuree Lee. "Recent Advances in Understanding the Roles of Pectin as an Active Participant in Plant Signaling Networks." Plants 10, no. 8 (August 19, 2021): 1712. http://dx.doi.org/10.3390/plants10081712.

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Pectin is an abundant cell wall polysaccharide with essential roles in various biological processes. The structural diversity of pectins, along with the numerous combinations of the enzymes responsible for pectin biosynthesis and modification, plays key roles in ensuring the specificity and plasticity of cell wall remodeling in different cell types and under different environmental conditions. This review focuses on recent progress in understanding various aspects of pectin, from its biosynthetic and modification processes to its biological roles in different cell types. In particular, we describe recent findings that cell wall modifications serve not only as final outputs of internally determined pathways, but also as key components of intercellular communication, with pectin as a major contributor to this process. The comprehensive view of the diverse roles of pectin presented here provides an important basis for understanding how cell wall-enclosed plant cells develop, differentiate, and interact.

6

Werchefani, Mouna, Catherine Lacoste, Hafedh Belguith, Ali Gargouri, and Chedly Bradai. "Effect of chemical and enzymatic treatments of alfa fibers on polylactic acid bio-composites properties." Journal of Composite Materials 54, no. 30 (July 13, 2020): 4959–67. http://dx.doi.org/10.1177/0021998320941579.

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Poor interfacial adhesion between vegetable fibers and bio-based thermoplastics is recognized as a serious drawback for biocomposite materials. To be applicable for a large-scale production, one should consider appropriate methods of natural fiber handling. This study presented poly(lactic acid) (PLA) reinforced with Alfa short fibers and four types of fiber treatment were selected. The effect of these treatments on the tensile properties and the morphology of biocomposites was studied. Composite samples were produced using a twin-screw extruder and an injection molding machine with a fiber percentage of 20 wt %. Prior to composite manufacture, Alfa fibers were subjected to mechanical, chemical and enzymatic modifications. The comparison of enzyme treated fibers and NaOH treated fibers was investigated by means of biochemical and morphological analyses. It was observed that enzymes decompose lignin, pectin and hemicelluloses from the fiber bundles interface leading to the reduction of technical fiber diameter and length. The elimination of these hydrophilic components resulted also in an increase of the water resistance of treated fibers. A bigger fiber-matrix interface area was thus created, which facilitated fiber-matrix adhesion and enhanced mechanical characteristics of the composites. SEM micrographs showed homogeneous distribution of treated fibers in the polymer matrix. Tensile strength of PLA biocomposites filled with pectinase treated fibers was increased by 27% over untreated samples. The data proved that enzymatic treatment can be used as an effective and ecofriendly strategy of fiber modification for natural fiber-reinforced composite production. These materials can be used in several domains such as construction, automotive applications and packaging industries.

7

Volchok, Anastasia, Alexandra Rozhkova, Ivan Zorov, Sergey Shcherbakov, and Arkady Sinitsyn. "Production of fruit wines using novel enzyme preparations." OENO One 49, no. 3 (September 30, 2015): 205. http://dx.doi.org/10.20870/oeno-one.2015.49.3.80.

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<p style="text-align: justify;"><strong>Aim</strong>: This work describes the activities of new-generation enzymatic preparations in fruit-berry substrates engineered for use in the fruit-wine industry. The enzymes were produced after genetic modification and selection of fungi <em>Penicillium verruculosum</em>, which produce efficient cellulase and pectinase enzymatic complexes. </p><p style="text-align: justify;"><strong>Methods and results</strong>: This paper covers the main characteristics of novel multi-enzyme complexes and the results of in-lab fruit-wine production with addition of enzymatic preparations, which could be used on an industrial scale. The juice yield and the content of suspended materials in the enzymatically treated samples were compared. Experiments included the sensory analysis of produced juices and fruit wines.</p><p style="text-align: justify;"><strong>Conclusion</strong>: Results show a significant increase in juice yield from the fruit pulp processed with the enzymatic preparations, without any negative effect on the quality and organoleptic attributes of the final product.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The obtained data clearly show that the use of the new-generation enzymatic preparations in the fruit-wine industry is effective.</p>

8

Western, Tamara L. "Changing spaces: the Arabidopsis mucilage secretory cells as a novel system to dissect cell wall production in differentiating cellsThis review is one of a selection of papers published in the Special Issue on Plant Cell Biology." Canadian Journal of Botany 84, no. 4 (April 2006): 622–30. http://dx.doi.org/10.1139/b06-008.

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As the outer boundary of plant cells, the cell wall is integral to all aspects of plant growth, development, and interactions with the environment. Dicot primary cell walls are composed of a network of cellulose, hemicellulose and proteins embedded in a matrix of acidic pectins. Pectins are synthesized in the Golgi apparatus by the sequential addition of nucleotide sugars by glycosyltransferases, following which they are secreted to the apoplast. During their differentiation, the mucilage secretory cells (MSCs) of the Arabidopsis seed coat undergo sequential biosynthesis and secretion of a primarily pectinaceous mucilage followed by secondary cell wall production. Several genes affecting MSC differentiation have been identified with roles ranging from the production of nucleotide sugar substrates for pectin synthesis to putative cell wall modification enzymes to transcription factors required to control MSC differentiation. These preliminary studies of the MSCs demonstrate that they will play a valuable role in gene discovery related to cell wall production and modification. Furthermore, they have the potential to become an important system in which to study the interaction and regulation of pectin biosynthetic factors in differentiating cells. These results will contribute to answering the important question of how cell wall production and modification occur throughout a growing plant living in a complex environment.

9

MATTHEW, J., S. HOWSON, M. KEENAN, and P. BELTON. "Improvement of the gelation properties of sugarbeet pectin following treatment with an enzyme preparation derived from Aspergillus niger — Comparison with a chemical modification." Carbohydrate Polymers 12, no. 3 (1990): 295–306. http://dx.doi.org/10.1016/0144-8617(90)90070-9.

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10

Kim, Yang, Martin A. K. Williams, Ashley L. Galant, Gary A. Luzio, Brett J. Savary, Prasanna Vasu, and Randall G. Cameron. "Nanostructural modification of a model homogalacturonan with a novel pectin methylesterase: Effects of pH on nanostructure, enzyme mode of action and substrate functionality." Food Hydrocolloids 33, no. 1 (August 2013): 132–41. http://dx.doi.org/10.1016/j.foodhyd.2013.02.015.

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Більше джерел

Дисертації з теми "Enzyme de modification des pectines":

1

Leschevin, Maïté. "Implication de la paroi végétale et plus particulièrement des enzymes de modification des pectines dans la tolérance au stress salin chez Arabidopsis." Thesis, Amiens, 2021. http://www.theses.fr/2021AMIE0027.

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La salinisation des sols est une situation préoccupante rencontrée dans plusieurs régions du monde où la pression sur l'eau devient de plus en plus forte, notamment en raison des changements climatiques et de la nécessité d'augmenter le rendement des cultures face à une population mondiale croissante. La présence d'un excès de sels dans le sol affecte les mécanismes physiologiques de la plante réduisant ainsi la production végétale. Une meilleure connaissance des mécanismes de défense des plantes en réponse au stress salin s'avère indispensable pour fournir des stratégies efficaces dans l'amélioration des cultures. La paroi végétale, première barrière physique entre le compartiment cellulaire végétal et l'environnement, a un rôle essentiel dans les mécanismes de croissance et de différentiation cellulaire et aussi en réponse à différents stress, dont le stress salin. La paroi végétale est une structure complexe et dynamique constituée principalement de polysaccharides (cellulose, hémicelluloses et pectines). Les pectines peuvent être méthylestérifiées et acétylées, les degrés de méthylestérification (DM) et d'acétylation (DA) sont contrôlés in muro par des enzymes spécifiques, les pectine méthylestérases (PME, EC 3.1.1.11) et acétylestérases (PAE, EC 3.1.1.6). Quelques données de la littérature montrent l'implication des pectines et du degré de méthylestérification de ces dernières, dans la tolérance au stress salin. Ces travaux avaient pour objectif d'incrémenter les données parcellaires actuelles sur le rôle de la paroi en réponse au stress salin. Trois stratégies d'étude distinctes ont été mises en place en choisissant comme modèle d'étude la plante glycophyte Arabidopsis thaliana. D'une part, la variabilité naturelle entre deux écotypes communs d'Arabidopsis thaliana (Wassilewskija, Ws et Columbia, Col-0) en réponse au stress salin a été caractérisée par une approche intégrative établissant une corrélation entre les résultats obtenus via des analyses physiologiques, biochimiques, métabolomiques et protéomiques. Les résultats ont montré une meilleure tolérance du stress salin associée au fond génétique Ws, avec un stade de développement plus avancé, une meilleure détoxification des espèces réactives à l'oxygène et une paroi plus riche en hémicelluloses et lignines. D'autre part, une approche de génétique inverse a été développée afin de déterminer les rôles fonctionnels des enzymes de modification des pectines AtPME3 et AtPAE7 dans la réponse au stress salin. Les résultats ont mis en évidence une perturbation du remodelage de la paroi par le stress salin. En effet, le stress salin induit une modulation des activités des enzymes de modification des pectines associée à une altération du patron de méthylestérification des pectines mais également à une réduction plus importante des homogalacturonanes et une augmentation des arabinanes par rapport aux plantes témoins. Enfin, une approche plus informative associant le métabolisme pariétal, la voie de détoxification des ions sodium, et l'impact des ions calcium sur la paroi a été menée afin de caractériser le remodelage pariétal induit par le stress salin chez le mutant hypersensible Atsos1 dont le gène SOS1 code un antiport Na+/H+ responsable de l'exclusion du Na+ à l'extérieur de la cellule. Les résultats préliminaires montrent une activité PME et PAE plus faibles que chez les plantes témoins en réponse au stress salin. Cela s'accompagne d'une réduction des acides galacturoniques et des résidus mannose. Ces résultats montrent que le remodelage des pectines et le mannose, semblent jouer un rôle prépondérant dans la tolérance au stress salin. L'ensemble des données confirme le rôle essentiel de la paroi et l'implication du calcium dans la tolérance au stress salin chez ce mutant
Soil salinization is a alarming situation encountered in several regions of the world where the pressure on water is becoming increasingly strong, especially due to climate change and the need to increase crop yields to face a global growing population. Excess of salt in soil affects plant physiological mechanism thus reducing plant production. A better knowledge of plant defense mechanism in response to salt stress is crucial to provide efficient strategies in crop yield. The plant cell wall is the first physical barrier between the plant cell compartment and the environment and plays an essential role in cell growth and development but also in response to various stresses, including salt stress. The cell wall is a highly complex and dynamic structure, mainly composed of polysaccharides (cellulose, hemicelluloses and pectins). Pectins can be methylesterified and acetylated, and their degree of methylesterification (DM) and acetylation (DA) can be modulated in muro by specific enzymes, pectin methylesterases (PMEs, EC 3.1.1.11) and acetylesterases (PAEs, EC 3.1. 1.6). Some parcelar data from the literature showed the role of pectins and their degree of methylesterification in tolerance to salt stress. The aim of this work was to provide new insights on the role of the cell wall in response to salt stress in the glycophyte Arabidopsis thaliana. Three distinct strategies were developed. Firstly, the natural variation between two common accessions of Arabidopsis thaliana (Wassilewskija, Ws and Columbia, Col-0) in response to salt stress has been characterized using an integrative approach establishing a correlation between physiological, biochemical, metabolomics and proteomics analyses. The results showed a better tolerance to salt stress associated with the genetic background Ws with an older developmental stage, a more efficient detoxification of reactive oxygen species and a higher content of xylan, mannan and lignin within the wall. Secondly, a reverse genetics approach has been developed to determine the contribution of two pectin remodeling enzymes, AtPME3 and AtPAE7 in salt tolerance. The results showed changes in the cell wall sugar composition as a reduction in homogalacturonan and an increase in arabinan in both atpme3 and atpae7 mutants after a long exposure to salt. Additionaly, salt stress induces a modulation of the PRE activities with an alteration of the pectin methylesterification pattern indicating a role of PME and PAE in cell wall integrity under salinity. Finally, a more informative approach combining cell wall metabolism, pectin remodeling enzymes, sodium ion detoxification pathway, and impact of calcium ions on cell wall integrity was carried out to characterize the role of the cell wall in the sodium hypersensitive mutant Atsos1. The SOS1 gene encodes a Na+/H+ antiporter which is involved in Na + exclusion. Preliminary results revealed that PME and PAE activities remained unchanged in atsos1 unlike the wild-type where the activites increased. That was associated with a reduction in pectin and mannan in atsos1, which was recovered by Ca2+ supply. All these data suggest the key role of atsos1 to maintain cell wall integrity under salt stress

2

Turbant, Amélie. "Modification des pectines et développement de la graine d'Arabidopsis thaliana." Amiens, 2014. http://www.theses.fr/2014AMIE0115.

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La paroi primaire des cellules végétales est composée majoritairement de polysaccharides, notamment de microfibrilles de cellulose et d'hémicelluloses maintenues dans une matrice de pectines (Cosgrove, 2001). Parmi ces dernières, les homogalacturonanes (HG) qui sont les plus abondants peuvent être modifiés par des enzymes pariétales à l'origine de changements de structure de la paroi (Yadav et al. , 2009). Les gènes codant certaines de ces enzymes sont exprimés dans la graine d'Arabidopsis thaliana, suggérant un rôle de celles-ci dans le développement de la graine. L'étude de mutants d'insertion obtenus pour certains de ces gènes a mis en évidence un rôle de la pectine méthylestérase 58 (PME58) dans la structuration du mucilage. Le mucilage est une matrice riche en pectines produite par les cellules épidermiques du tégument de la graine et libérée lors de leur imbibition. Notre étude a montré que la PME58 est impliquée dans la déméthylestérification des HG présents dans le mucilage, dont la majorité provient probablement de la fragmentation des parois primaires des cellules épidermiques lors de l'extrusion du mucilage. L'étude des mutants pme58 par des approches analytiques et par immunodétection a montré que la PME58 est impliquée dans la régulation de la structuration et de la cohésion du mucilage, via la modulation des interactions entre les composants pectiques et cellulosiques

3

L'Enfant, Mélanie. "Inhibition spécifique d'enzymes de modification et de dégradation des pectines." Amiens, 2014. http://www.theses.fr/2014AMIE0108.

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Les pectines méthylestérases (PME, EC. 3. 1. 1. 11) et les polygalacturonases (PG, EC. 3. 2. 1. 15) sont des enzymes qui catalysent respectivement la déméthylestérification et la dépolymérisation des homogalacturonanes, constituant majoritaire de la paroi primaire. Ceci conduit à des modifications structurales de la paroi végétale, et a des conséquences sur le développement et la réponse aux stress. Ces enzymes sont présentes chez les plantes mais sont également sécrétées par des phytopathogènes comme Botrytis cinerea, favorisant la colonisation de l'hôte. Afin de mieux comprendre les spécificités des enzymes de plantes vis-à-vis de celles de phytopathogènes, et d'identifier des inhibiteurs chimiques potentiels de ces enzymes, différentes approches ont été mises en œuvre. Des enzymes (PME/PG) d'Arabidopsis thaliana et de Botrytis ont été produites en système hétérologue afin de tester leur spécificité de substrat et de pH. Les substrats pectiques utilisés diffèrent par leurs degrés et patrons de méthylestérification. Dans le but d'identifier des inhibiteurs de ces enzymes, des molécules naturelles, des oligosaccharides bioisostères modifiés chimiquement au niveau du méthyle en C6 par différents groupements ainsi que des molécules chimiques issues d’une chimiothèque ont été testés. Les résultats obtenus montrent que, les enzymes de Botrytis cinerea (BcPME 1, BcPG 2 et BcPG 3) n'ont pas les mêmes spécificités de substrat et dépendance de pH que celles d'Arabidopsis (AtPME3, AtPME31 et AtPG80). En particulier, BcPME 1 montre une spécificité pour des HG de degrés de méthylestérification élevés à pH 4, alors que PME 3 et PME 31 sont plus actives à des pH de 6 et 7,5. Par ailleurs, PME 3 et PME 31 diffèrent dans leurs préférences de substrats, permettant de dégager des hypothèses quant à leurs rôles in planta. Ce travail a par ailleurs permis de montrer que les enzymes de plantes sont facilement inhibées par des molécules naturelles et chimiques, au contraire des enzymes de Botrytis. Enfin, le screen d'un chimiothèque a permis d'identifier de nouveaux inhibiteurs de l'activité PME

4

Overton, Nigel. "Enzyme catalysed modification of polymers." Thesis, Aston University, 1998. http://publications.aston.ac.uk/9608/.

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The aim of this project was to investigate the enzyme catalysed modification of synthetic polymers. It was found that an immobilised lipase from Candida antartica (Novozyme 435) catalysed the selective epoxidation of poly(butadiene) in the presence of hydrogen peroxide and catalytic quantities of acetic acid. The cis and trans double bonds of the backbone were epoxidised in yields of up to 60 % whilst the pendent vinyl groups were untouched. The effect of varying a number of reaction parameters was investigated. These studies suggested that higher yields of epoxide could not be obtained because of the conformational properties of the partially epoxidised polymer. Application of this process to the Baeyer-Villiger reaction of poly(vinyl phenyl ketone) and poly(vinyl methyl ketone) were unsuccessful. The lack of reactivity was found to be a property of the polymer rather than the enzymatic system employed. Attempts to modify hydroxyl containing polymers and polymers bearing active esters close to the polymer backbone were unsuccessful. Steric factors appear to be the most important influence on the outcome of the reactions.

5

Windle, Claire Louise. "Altering enzyme activities using chemical modification." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/11808/.

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In Nature there are twenty proteogenic amino acid ‘building blocks’, from which proteins and enzymes are constructed. These proteogenic amino acids confer activity to enzymes; however there are many instances where the chemistries provided by these ‘building blocks’ are expanded upon. Nature recruits an array of cofactors, post translational modifications and post translationally generated cofactors, all which help to provide function or activity. Until recently the protein engineer was restricted to the use of the twenty proteogenic amino acids, and so access to this increased chemical diversity was highly challenging. In this thesis, chemical modification has been used to insert a variety of non canonical amino acids (ncAAs) throughout the active site of the enzyme N acetylneuraminic acid lyase (NAL). This modification method incorporates ncAAs site specifically into a protein, via a dehydroalanine intermediate and conjugate addition with a thiol compound. Initial work using this method replaced the catalytic lysine at position 165 with the non canonical analogue γ thialysine. It was possible to obtain homogenously modified protein in high yields for detailed kinetic and X ray crystallographic studies, and therefore possible to elucidate the catalytic and structural consequences of this modification. The work to replace Lys165 with a non canonical analogue provided a starting point to expand the incorporation of ncAAs into NAL. A total of thirteen different non canonical side chains were incorporated, individually, at thirteen different positions within the active site of NAL. These modified enzymes were then screened for activity with ten different substrates to determine the effects of ncAA incorporation. It was seen that the ncAAs were well tolerated by the enzyme, as active modified enzymes were produced. By incorporating ncAAs it was possible to alter the substrate specificity of the enzyme. The modified enzyme F190Dpc, containing a dihydroxypropyl cysteine side chain, was found to have an increased activity with an altered substrate, erythrose. This activity was higher than the wild type enzyme with both the altered substrate and the wild type substrate, and the non canonical Dpc side chain outperformed any of the proteogenic amino acids when inserted at the same position in the protein, for the substrate erythrose. This research begins to explore the possibilities of what may be achieved by use of ncAAs. Facile incorporation of ncAAs will allow protein engineers to take inspiration from Nature and expand the chemistries provided by the proteogenic amino acids, hopefully to engineer novel activities or catalysis.

6

O'Neil, Crystal L. "Enzyme Exploitation: Manipulating Enzyme Function for Therapy, Synthesis and Natural Product Modification." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1293722936.

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7

Pirinccioglu, Necmettin. "Modification of reactivity by supramolecular complex formation." Thesis, University of Kent, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309749.

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8

Hernandez, Diana Raquel. "Regulation of Expression of a Neisseria Gonorrhoeae tRNA-Modification Enzyme (Gcp)." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/242381.

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Neisseria gonorrhoeae (Ng) encounters different microenvironments during its life-cycle. Some of these niches have different concentrations of oxygen, which influences the rate of Ng growth; as well as iron, an element essential for Ng survival. Differential expression of several proteins allows the bacteria to adapt to the diverse conditions it comes encounters. One protein affected by environmental changes during Ng growth is Gcp, a tRNA-modification enzyme essential for protein synthesis. To study the regulation of expression of Gcp, we first analyzed the sequence of its ORF, gcp. Orthologs of this gene are found in all kingdoms of life. In silico analysis shows that among Neisseria species, gcp ranges in homology from 76% to 99%, at the nucleotide level. Reverse transcription PCR indicates that gcp is expressed as part of an operon, together with three cytochrome-associated genes cyc4, resB and resC. Rapid amplification of complementary DNA ends determined the start of transcription of cyc4 (and possibly of the cyc4-gcp operon) at 95 nucleotides from the gene start codon. Transcriptional fusions determined that the promoter region upstream of cyc4 is the strongest promoter in the operon. However, the region directly upstream of gcp also has low level of promoter activity, suggesting that the gene may be expressed from two different promoters. Semi-quantitative determination of the concentration of gcp mRNA indicates that the transcription of the gene is significantly repressed when Ng is grown under low iron or low oxygen conditions. Analysis of an fnr mutant, grown under the same conditions as its parental wild type, indicates that the FNR transcriptional regulator is involved in the repression of gcp in low iron or low oxygen conditions. Contrary to expectation, the cyc4 promoter is upregulated when Ng is grown under low oxygen or low iron conditions. However, these results cannot be compared to the original promoter strength. Determination of which was performed on bacteria grown in liquid medium. Coregulation of gcp with cytochrome genes can guarantee low levels of protein synthesis when Ng encounters adverse microenvironments and needs its energy redirected to the expression of genes that would allow it to survive.

9

Olsen, Greta A. "Characterization and modification of fluorogenic substrate coated particles for use as enzyme probes." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/27553.

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10

Aydemir, Adnan [Verfasser]. "Modeling of enzyme catalyzed racemic reactions and modification of enantioselectivity / Adnan Aydemir." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover, 2010. http://d-nb.info/1009543792/34.

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Більше джерел

Книги з теми "Enzyme de modification des pectines":

1

Bearne, Stephen Lewis *. Enzyme inhibition by phosphonates and protein modification by dicarboxylic acid bis (methyl phosphates). 1991.

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2

Mortimer, Pamela. Development of an enzyme linked immunosorbent assay for the detection of hepatitis A IgG and modification of a commercial hepatitis A screening kit for avidity studies. 1995.

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3

Puntis, John. Carbohydrate intolerance. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198759928.003.0020.

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Symptoms such as watery diarrhoea, wind, and abdominal cramps should raise the possibility of carbohydrate intolerance. Lactose maldigestion is the most common cause and can be transient, after gastroenteritis, or in some populations is genetically determined with increasing age. Congenital sucrase–isomaltase deficiency (CSID) is underdiagnosed but amenable to treatment with dietary modification and oral enzyme replacement. Glucose–galactose malabsorption presents with watery diarrhoea from the time of first feeds. Investigations include sugar chromatography (when available), breath hydrogen testing, mucosal enzyme assay, and gene testing for CSID.

4

The Enzymes, Third Edition (The Enzymes). 3rd ed. Academic Press, 2001.

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5

Cooper, Bruce Andrew. Normal physiology of the renal system. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0208.

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Patients with critical illness often have renal dysfunction, either primary or secondary, that can both complicate and prolong their medical management. Therefore, an understanding of normal renal physiology can help recognize the process or processes that caused the renal dysfunction, and determine the most appropriate corrective and supportive care. The kidney has many important roles other than just urine production. The impact of kidney disease is often predictable. The kidney plays a critical role in fluid and electrolyte balance via many specialized transmembrane pathways. The kidney is also involved in the production and modification of two key hormones and one enzyme. Understanding normal renal physiology can help determine clinical management.This chapter summarizes the important aspects of renal physiology relevant to those who work in a critical care environment.

Частини книг з теми "Enzyme de modification des pectines":

1

Liu, Wei, and C. L. Tsou. "Kinetics of Irreversible Modification of Enzyme Activity." In Enzyme Dynamics and Regulation, 289–300. New York, NY: Springer New York, 1988. http://dx.doi.org/10.1007/978-1-4612-3744-0_34.

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2

Baici, Antonio. "Dichotomous Keys to Enzyme-Modification Mechanisms." In Kinetics of Enzyme-Modifier Interactions, 463–76. Vienna: Springer Vienna, 2015. http://dx.doi.org/10.1007/978-3-7091-1402-5_10.

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3

Ellis, Andrew. "Protein Modification to Meet the Demands of the Food Industry." In Industrial Enzyme Applications, 125–41. Chichester, UK: John Wiley & Sons, Ltd, 2019. http://dx.doi.org/10.1002/9783527813780.ch2_2.

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4

Ara, Kazi Zubaida Gulshan, Samiullah Khan, Tejas S. Kulkarni, Tania Pozzo, and Eva Nordberg Karlsson. "Glycoside Hydrolases for Extraction and Modification of Polyphenolic Antioxidants." In Advances in Enzyme Biotechnology, 9–21. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1094-8_2.

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5

Schoonen, Lise, and Jan C. M. van Hest. "Modification of CCMV Nanocages for Enzyme Encapsulation." In Methods in Molecular Biology, 69–83. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4939-7893-9_6.

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6

Chakraborty, Soma, Bishwabhusan Sahoo, Iwao Teraoka, Lisa M. Miller, and Richard A. Gross. "Enzyme-Catalyzed Regioselective Modification of Starch Nanoparticles." In ACS Symposium Series, 246–65. Washington, DC: American Chemical Society, 2005. http://dx.doi.org/10.1021/bk-2005-0900.ch017.

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7

Shi, J. P., S. X. Lin, S. T. Huang, F. Miao, and Y. L. Wang. "Modification of Leucyl-tRNA Synthetase by Affinity Labeling and Limited Proteolysis." In Enzyme Dynamics and Regulation, 367–76. New York, NY: Springer New York, 1988. http://dx.doi.org/10.1007/978-1-4612-3744-0_42.

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8

Kruus, Kristiina, Marja-Leena Niku-Paavola, and Liisa Viikari. "Laccase — a Useful Enzyme for Modification of Biopolymers." In Biorelated Polymers, 255–61. Boston, MA: Springer US, 2001. http://dx.doi.org/10.1007/978-1-4757-3374-7_23.

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9

Veronese, Francesco M., Paolo Caliceti, and Oddone Schiavon. "New Synthetic Polymers for Enzyme and Liposome Modification." In ACS Symposium Series, 182–92. Washington, DC: American Chemical Society, 1997. http://dx.doi.org/10.1021/bk-1997-0680.ch013.

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10

Holzer, H. "Regulation of Enzymes by Enzyme-Catalyzed Chemical Modification." In Advances in Enzymology - and Related Areas of Molecular Biology, 297–326. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2006. http://dx.doi.org/10.1002/9780470122778.ch7.

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Тези доповідей конференцій з теми "Enzyme de modification des pectines":

1

Xue, Yong, Shu-Bai Li, Hai-Tao Zhang, Hua-Li Nie, Li-Min Zhu, and C. Branford-White. "Enzyme Design by Chemical Modification of Papain Lysine." In 2009 3rd International Conference on Bioinformatics and Biomedical Engineering (iCBBE). IEEE, 2009. http://dx.doi.org/10.1109/icbbe.2009.5162789.

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2

Djebbi, M. A., K. Charradi, A. Ben Haj Amara, and H. Ben Rhaiem. "Immobilization of LDh enzyme on Layered Double Hydroxides: Structural and morphological modification." In 2014 International Conference on Composite Materials & Renewable Energy Applications (ICCMREA). IEEE, 2014. http://dx.doi.org/10.1109/iccmrea.2014.6843803.

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3

Ochi, Anna, and Hiroyuki Hori. "Complex Formations between Artificial RNA-DNA Chimera Nucleic Acids and RNA Modification Enzyme." In 2007 International Symposium on Micro-NanoMechatronics and Human Science. IEEE, 2007. http://dx.doi.org/10.1109/mhs.2007.4420836.

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4

Kurimoto, Ryota, Hiroki Tsutsumi, Saki Ikeuchi, and Hiroshi Asahara. "Abstract 2370: Tumor suppression potential of tRNA modification enzyme TruBs via let-7." In Proceedings: AACR Annual Meeting 2021; April 10-15, 2021 and May 17-21, 2021; Philadelphia, PA. American Association for Cancer Research, 2021. http://dx.doi.org/10.1158/1538-7445.am2021-2370.

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5

Matsumoto, Keisuke, Masato Abe, Yoshitaka Takano, Naoyuki Takayanagi, Yaeta Endo, and Hiroyuki Hori. "Hetero Subunits Assembly Study of RNA Modification Enzyme by Wheat Germ Cell-Free Translation System." In 2006 IEEE International Symposium on MicroNanoMechanical and Human Science. IEEE, 2006. http://dx.doi.org/10.1109/mhs.2006.320252.

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6

"Carbon Electrode based Urea Sensor - Modification of Graphite and New Polymeric Carriers for Enzyme Immobilization." In International Conference on Biomedical Electronics and Devices. SciTePress - Science and and Technology Publications, 2013. http://dx.doi.org/10.5220/0004326901970201.

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7

Mazlan, Siti Zulaikha, and Sharina Abu Hanifah. "Synthesis and effect of modification on methacylate - acrylate microspheres for Trametes versicolor laccase enzyme immobilization." In THE 2014 UKM FST POSTGRADUATE COLLOQUIUM: Proceedings of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology 2014 Postgraduate Colloquium. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4895206.

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8

Benimetskaya, L. Z., I. I. Gitelzon, Andrew L. Kozionov, S. Y. Novozhilov, V. N. Petushkov, N. S. Rodionova, and Mark I. Stockman. "Localization of the active site of an enzyme, bacterial luciferase, using two-quantum affinity modification." In Berlin - DL tentative, edited by Lars O. Svaasand. SPIE, 1991. http://dx.doi.org/10.1117/12.48227.

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9

Yao, Eric, Shenshen Lai, and Jun Yan. "Abstract 3862: Empowering research on ubiquitin and ubiquitin-like protein modification cascade using recombinant enzyme systems." In Proceedings: AACR Annual Meeting 2018; April 14-18, 2018; Chicago, IL. American Association for Cancer Research, 2018. http://dx.doi.org/10.1158/1538-7445.am2018-3862.

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10

Intarasit, Sitthisak, Kamolchanok Umnajkitikorn, and Kobkiat Saengnil. "Nitric oxide level modification on antioxidant enzyme activity, antioxidant capacity and pericarp browning of postharvest longan fruit." In ICBBB '22: 2022 12th International Conference on Bioscience, Biochemistry and Bioinformatics. New York, NY, USA: ACM, 2022. http://dx.doi.org/10.1145/3510427.3510444.

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Звіти організацій з теми "Enzyme de modification des pectines":

1

Delmer, Deborah, Nicholas Carpita, and Abraham Marcus. Induced Plant Cell Wall Modifications: Use of Plant Cells with Altered Walls to Study Wall Structure, Growth and Potential for Genetic Modification. United States Department of Agriculture, May 1995. http://dx.doi.org/10.32747/1995.7613021.bard.

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Our previous work indicated that suspension-cultured plant cells show remarkable flexibility in altering cell wall structure in response either to growth on saline medium or in the presence of the cellulose synthesis inhibitor 2,-6-dichlorobenzonitrile (DCB). We have continued to analyze the structure of these modified cell walls to understand how the changes modify wall strength, porosity, and ability to expand. The major load-bearing network in the walls of DCB-adapted dicot cells that lack a substantial cellulose-xyloglucan network is comprised of Ca2+-bridged pectates; these cells also have an unusual and abundant soluble pectic fraction. By contrast, DCB-adapted barley, a graminaceous monocot achieves extra wall strength by enhanced cross-linking of its non-cellulosic polysaccharide network via phenolic residues. Our results have also shed new light on normal wall stucture: 1) the cellulose-xyloglucan network may be independent of other wall networks in dicot primary walls and accounts for about 70% of the total wall strength; 2) the pectic network in dicot walls is the primary determinant of wall porosity; 3) both wall strength and porosity in graminaceous monocot primary walls is greatly influenced by the degree of phenolic cross-linking between non-cellulosic polysaccharides; and 4) the fact that the monocot cells do not secrete excess glucuronoarabinoxylan and mixed-linked glucan in response to growth on DCB, suggests that these two non-cellulosic polymers do not normally interact with cellulose in a manner similar to xyloglucan. We also attempted to understand the factors which limit cell expansion during growth of cells in saline medium. Analyses of hydrolytic enzyme activities suggest that xyloglucan metabolism is not repressed during growth on NaCl. Unlike non-adapted cells, salt-adapted cells were found to lack pectin methyl esterase, but it is not clear how this difference could relate to alterations in wall expansibility. Salt-adaped cell walls contain reduced hyp and secrete two unique PRPP-related proteins suggesting that high NaCl inhibits the cross-linking of these proteins into the walls, a finding that might relate to their altered expansibility.

2

Doichev, Kostadin, Veselina Georgieva, Elitsa Boteva, and Rumiana Mironova. Modification of DNA with Glucose 6-Phosphate to Examine the Glycolytic Enzyme Phosphoglucose Isomerase for DNA-amadoriase Activity. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, June 2021. http://dx.doi.org/10.7546/crabs.2021.06.06.

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3

Schaffer, Arthur, Jack Preiss, Marina Petreikov, and Ilan Levin. Increasing Starch Accumulation via Genetic Modification of the ADP-glucose Pyrophosphorylase. United States Department of Agriculture, October 2009. http://dx.doi.org/10.32747/2009.7591740.bard.

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The overall objective of the research project was to utilize biochemical insights together with both classical and molecular genetic strategies to improve tomato starch accumulation. The proposal was based on the observation that the transient starch accumulation in the immature fruit serves as a reservoir for carbohydrate and soluble sugar content in the mature fruit, thereby impacting on fruit quality. The general objectives were to optimize AGPase function and activity in developing fruit in order to increase its transient starch levels. The specific research objectives were to: a) perform directed molecular evolution of the limiting enzyme of starch synthesis, AGPase, focussing on the interaction of its regulatory and catalytic subunits; b) determine the mode of action of the recently identified allelic variant for the regulatory subunit in tomato fruit that leads to increased AGPase activity and hence starch content. During the course of the research project major advances were made in understanding the interaction of the small and large subunits of AGPase, in particular the regulatory roles of the different large subunits, in determining starch synthesis. The research was performed using various experimental systems, including bacteria and Arabidopsis, potato and tomato, allowing for broad and meaningful conclusions to be drawn. A novel discovery was that one of the large subunits of tomato AGPase is functional as a monomer. A dozen publications describing the research were published in leading biochemical and horticultural journals. The research results clearly indicated that increasing AGPase activity temporally in the developing fruit increase the starch reservoir and, subsequently, the fruit sugar content. This was shown by a comparison of the carbohydrate balance in near-isogenic tomato lines differing in a gene encoding for the fruit-specific large subunit (LS1). The research also revealed that the increase in AGPase activity is due to a temporal extension of LS1 gene expression in the developing fruit which in turn stabilizes the limiting heterotetrameric enzyme, leading to sustained starch synthesis. This genetic variation can successfully be utilized in the breeding of high quality tomatoes.

4

Library, Spring. Where Does Current Quorum Sensing Research Stand. Spring Library, December 2020. http://dx.doi.org/10.47496/sl.blog.16.

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Quorum quenching is achieved by inactivating signalling enzymes, by introducing molecules that mimic signalling molecules and block their receptors, by degrading signalling molecules themselves, or by a modification of the quorum sensing signals due to an enzyme activity.

5

Cohen, Jerry D., and Ephraim Epstein. Metabolism of Auxins during Fruit Development and Ripening. United States Department of Agriculture, August 1995. http://dx.doi.org/10.32747/1995.7573064.bard.

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We had proposed to look at several aspects of auxin metabolism in fruit tissues: 1) IAA biosynthesis from tryptophan and IAA biosynthesis via the non-tryptophan pathway; 2) changes in the capacity to form conjugates and catabolites of auxin at different times during fruit development and; 3) the effects of modifying auxin metabolism in fruit tissues. The latter work focused primarily on the maize iaglu gene, with initial studies also using a bacterial gene for hydrolysis of IAA-aspartate. These metabolic and molecular studies were necessary to define potential benefits of auxin metabolism modification and will direct future efforts for crop improvement by genetic methods. An in vitro system was developed for the production of tomato fruit in culture starting from immature flowers in order to ascertain the effect of auxin modification on fruit ripening. IAA supplied to the fruit culture media prior to breaker stage resulted in an increase in the time period between breaker and red-ripe stages from 7 days without additional IAA to 12 days when 10-5 M IAA was added. These results suggest that significant changes in the ripening period could be obtained by alteration of auxin relationships in tomato fruit. We generated transgenic tomato plants that express either the maize iaglu gene or reduced levels of the gene that encodes the enzyme IAA-glucose synthetase. A modified shuttle vector pBI 121 expressing the maize iaglu gene in both sense and antisense orientations under a 35S promoter was used for the study. The sense plants showed total lack of root initiation and development. The antisense transgenic plants, on the other hand, had unusually well developed root systems at early stages in development. Analysis showed that the amount and activity of the endogenous 75 kDa IAGLU protein was reduced in these plants and consequently these plants had reduced levels of IAA-glucose and lower overall esterified IAA.

6

Rahimipour, Shai, and David Donovan. Renewable, long-term, antimicrobial surface treatments through dopamine-mediated binding of peptidoglycan hydrolases. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597930.bard.

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There is a need for renewable antimicrobial surface treatments that are semi- permanent, can eradicate both biofilms and planktonic pathogens over long periods of time and that do not select for resistant strains. This proposal describes a dopamine binding technology that is inexpensive, bio-friendly, non-toxic, and uses straight-forward commercially available products. The antimicrobial agents are peptidoglycanhydrolase enzymes that are non-toxic and highly refractory to resistance development. The goal of this project is to create a treatment that will be applicable to a wide variety of surfaces and will convey long-lasting antimicrobial activity. Although the immediate goal is to create staphylolytic surfaces, the technology should be applicable to any pathogen and will thus contribute to no less than 3 BARD priorities: 1) increased animal production by protecting animals from invasive and emerging diseases, 2) Antimicrobial food packaging will improve food safety and security and 3) sustainable bio- energy systems will be supported by coating fermentation vats with antimicrobials that could protect ethanolic fermentations from Lactobacillus contamination that reduces ethanol yields. The dopamine-based modification of surfaces is inspired by the strong adhesion of mussel adhesion proteins to virtually all types of surfaces, including metals, polymers, and inorganic materials. Peptidoglycanhydrolases (PGHs) meet the criteria of a surface bound antimicrobial with their site of action being extracellular peptidoglycan (the structural basis of the bacterial cell wall) that when breached causes osmotic lysis. As a proof of principle, we will develop technology using peptidoglycanhydrolase enzymes that target Staphylococcus aureus, a notoriously contagious and antimicrobial-resistant pathogen. We will test for susceptibility of the coating to a variety of environmental stresses including UV light, abrasive cleaning and dessication. In order to avoid resistance development, we intend to use three unique, synergistic, simultaneous staphylococcal enzyme activities. The hydrolases are modular such that we have created fusion proteins with three lytic activities that are highly refractory to resistance development. It is essential to use multiple simultaneous activities to avoid selecting for antimicrobial resistant strains. This strategy is applicable to both Gram positive and negative pathogens. We anticipate that upon completion of this award the technology will be available for commercialization within the time required to achieve a suitable high volume production scheme for the required enzymes (~1-2 years). We expect the modified surface will remain antimicrobial for several days, and when necessary, the protocol for renewal of the surface will be easily applied in a diverse array of environments, from food processing plants to barnyards.

7

Meiri, Noam, Michael D. Denbow, and Cynthia J. Denbow. Epigenetic Adaptation: The Regulatory Mechanisms of Hypothalamic Plasticity that Determine Stress-Response Set Point. United States Department of Agriculture, November 2013. http://dx.doi.org/10.32747/2013.7593396.bard.

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Our hypothesis was that postnatal stress exposure or sensory input alters brain activity, which induces acetylation and/or methylation on lysine residues of histone 3 and alters methylation levels in the promoter regions of stress-related genes, ultimately resulting in long-lasting changes in the stress-response set point. Therefore, the objectives of the proposal were: 1. To identify the levels of total histone 3 acetylation and different levels of methylation on lysine 9 and/or 14 during both heat and feed stress and challenge. 2. To evaluate the methylation and acetylation levels of histone 3 lysine 9 and/or 14 at the Bdnfpromoter during both heat and feed stress and challenge. 3. To evaluate the levels of the relevant methyltransferases and transmethylases during infliction of stress. 4. To identify the specific localization of the cells which respond to both specific histone modification and the enzyme involved by applying each of the stressors in the hypothalamus. 5. To evaluate the physiological effects of antisense knockdown of Ezh2 on the stress responses. 6. To measure the level of CpG methylation in the promoter region of BDNF in thermal treatments and free-fed, 12-hour fasted, and re-fed chicks during post-natal day 3, which is the critical period for feed-control establishment, and 10 days later to evaluate longterm effects. 7. The phenotypic effect of antisense “knock down” of the transmethylaseDNMT 3a. Background: The growing demand for improvements in poultry production requires an understanding of the mechanisms governing stress responses. Two of the major stressors affecting animal welfare and hence, the poultry industry in both the U.S. and Israel, are feed intake and thermal responses. Recently, it has been shown that the regulation of energy intake and expenditure, including feed intake and thermal regulation, resides in the hypothalamus and develops during a critical post-hatch period. However, little is known about the regulatory steps involved. The hypothesis to be tested in this proposal is that epigenetic changes in the hypothalamus during post-hatch early development determine the stress-response set point for both feed and thermal stressors. The ambitious goals that were set for this proposal were met. It was established that both stressors i.e. feed and thermal stress, can be manipulated during the critical period of development at day 3 to induce resilience to stress later in life. Specifically it was established that unfavorable nutritional conditions during early developmental periods or heat exposure influences subsequent adaptability to those same stressful conditions. Furthermore it was demonstrated that epigenetic marks on the promoter of genes involved in stress memory are altered both during stress, and as a result, later in life. Specifically it was demonstrated that fasting and heat had an effect on methylation and acetylation of histone 3 at various lysine residues in the hypothalamus during exposure to stress on day 3 and during stress challenge on day 10. Furthermore, the enzymes that perform these modifications are altered both during stress conditioning and challenge. Finally, these modifications are both necessary and sufficient, since antisense "knockdown" of these enzymes affects histone modifications, and as a consequence stress resilience. DNA methylation was also demonstrated at the promoters of genes involved in heat stress regulation and long-term resilience. It should be noted that the only goal that we did not meet because of technical reasons was No. 7. In conclusion: The outcome of this research may provide information for the improvement of stress responses in high yield poultry breeds using epigenetic adaptation approaches during critical periods in the course of early development in order to improve animal welfare even under suboptimum environmental conditions.