Search results for "saccharide"
showing 10 items of 849 documents
A FTIR study on low hydration saccharide amorphous matrices: Thermal behaviour of the Water Association Band
2011
Abstract We report a study on the thermal behaviour of the infrared Water Association Band (WAB) in dry binary saccharide–water systems (containing trehalose, sucrose, maltose, and raffinose). This is a follow-up of preceding studies on analogous carboxymyoglobin-saccharide–water ternary systems, which pointed out a mutual protein-matrix influence (coupling). A comparison between binary and ternary systems, for all the saccharides studied, evidences a reduction in the residual water content in the latter and, except for trehalose, a sizable modification in the thermal behaviour, which is discussed in terms of structure and hydrogen bonding properties of the sugars. The study allowed us also…
Medicago truncatula
2012
In plants, long distance transport of sugars from photosynthetic source leaves to sink organs comprises different crucial steps depending on the species and organ types. Sucrose, the main carbohydrate for long distance transport is synthesized in the mesophyll and then loaded into the phloem. After long distance transport through the phloem vessels, sucrose is finally unloaded towards sink organs. Alternatively, sugar can also be transferred to non‐plant sinks and plant colonization by heterotrophic organisms increases the sink strength and creates an additional sugar demand for the host plant. These sugar fluxes are coordinated by transport systems. Main sugar transporters in plants compri…
Trehalose and trehalose-6-phosphate induce stomatal movements and interfere with ABA-induced stomatal closure in grapevine
2015
Aims: The effects of trehalose and trehalose-6-phosphate (T6P), among other sugars, were assessed on grapevine stomatal movements. Methods and results: Epidermal peels were used to assess the effects of sugars. Low concentrations of trehalose and T6P (1 μM) induced an osmotic-independent reduction of the stomatal aperture in light conditions. Furthermore, ABA-induced stomatal closure was reduced by sugar application in association with lower accumulation of reactive oxygen species in guard cells. Similar effects, although weaker, were observed in response to the disaccharides sucrose and maltose, but not in response to the monosaccharides fructose and glucose. Conclusion: This study clearly…
Isolation of soil lignins by combination of ball-milling and cellulolysis: Evaluation of purity and isolation efficiency with pyrolysis/GC/MS
2009
Abstract CuO oxidation is traditionally used for soil lignin study, although, like other degradation methods it might give access only to a part of the lignin polymers. For structural characterization, lignins are conventionally isolated from plant material by combining ball-milling, cellulolysis and solvent extraction to recover a milled wall enzymatic lignin (MWEL) fraction. This method might isolate condensed lignins, which are not accounted for CuO oxidation. MWELs are still associated with polysaccharides. This study aimed to evaluate if the MWEL method can be used complementary to CuO oxidation for soil lignin studies. We assessed the purity of isolated lignins by pyrolytic characteri…
Influence of solvent-free reticulation treatment on edible film properties based on chitosan and gelatin, containing or not natural antioxidants : ph…
2015
This thesis aims to develop an edible packaging made of a mixture of chitosan and gelatin (beef or fish), to better understand the influence of the electron beam irradiation and of the incorporation of natural antioxidants on the physico-chemical and functional properties of the films. A study of the effect of irradiation on antioxidants release kinetics in a simple liquid medium was studied for validation. A preliminary study first showed that the densification of the film-forming solution and the gel during drying does not depend on the thickness or concentration or time and suggests a Fickian diffusion of water in the matrix. The permeability to water vapor increases linearly with film t…
[Norovirus infections: an overview]
2010
National audience; Noroviruses belong to the Caliciviridae family. They are a major cause of sporadic cases and outbreaks of gastroenteritis in all age groups, and are responsible for a considerable disease burden in industrialized countries. Noroviruses are single-stranded RNA viruses, and show great genetic diversity making their detection difficult. Noroviruses can be divided into 5 genogroups, which themselves are subdivided into genotypes. Besides chance mutations that occur during viral replication, the great heterogeneity observed among noroviruses is also due to intra and inter-genotypic recombination events between strains. Some of these new variants or new recombinants are frequen…
Contribution a l'etude de certains facteurs physiques et chimiques culturaux sur la production et les caracteristiques de la cellulose synthetisee pa…
1993
188 ref. Diplôme : Dr. Ing.
Etude du système de perception des chito--oligosaccharides chez la vigne et rôle dans l'immunité.
2014
Rapport de stage Master II R SPE IPM; Master
Réponses des cellules de Nicotiana tabacum à des molécules microbiennes : évènements de signalisation précoce, influence de la dynamique membranaire …
2018
Responses of Nicotiana tabacum cells to microbial molecule treatments: early signaling events,influence of membrane dynamics, and sugar fluxesIn their natural environment plants are in close interaction with beneficial, neutral, or pathogenicmicrobes, which are highly dependent on carbon resources exuded by plant roots. Sugar transport, which isa key process of plant physiology, is essential to support the fate of plant-microbe interactions. Duringevolution, plants have acquired the ability to perceive microbial molecules, initiating specific signaltransduction cascades and leading to adapted response for microbe lifestyles (avirulent, virulent, or benefic).Plant survival will depend on the…
Recherche de récepteurs de l’immunité des plantes et étude de l’impact de biostimulants sur leur expression et la résistance induite chez des organes…
2021
National audience; La stimulation des défenses immunitaires des plantes représente une stratégie durable deprotection des cultures qui pourrait permettre de réduire l’utilisation de pesticides chimiquesencore trop répandue en viticulture. Son principe réside en l’application, au contact des cellulesvégétales, de molécules élicitrices détectées comme des signaux de danger par la plante. Cessignaux de dangers peuvent être de différente nature et origine comme par exemple la chitine,un chito-oligosaccharide (COS) retrouvé dans les parois fongiques. Leur détection par desrécepteurs de l’immunité entraine une cascade de signalisation complexe, conduisant àl’activation de réactions de défense et …