Search results for "PLASMA"
showing 10 items of 4043 documents
Plasmalogen metabolism in retinal glial cells : interaction between cells during normal or pathological vascular development
2017
Retinal vascular disorders such as retinopathy of prematurity (ROP), diabetic retinopathy or age-related macular degeneration represent the first cause of vision loss at all ages in industrialized countries. Many epidemiological or animal studies have shown the involvement of polyunsaturated fatty acids (PUFA) in the regulation of vascular development and more specifically the beneficial properties of omega 3 PUFA (n-3 PUFA) against pathological vascularization. Those PUFA are esterified on glycerophospholipids (GP). GP are the primary constituents of the lipid bilayer of cell membranes. PUFA can be also esterified on a specific class of GP, called plasmalogens. Plasmalogens are characteriz…
Involvement of the plasma membrane in saccharomyces cerevisiae resistance to hydric perturbations : key role of ergosterol
2011
Preservation of microorganisms of interest (ferments, probiotics) in dry form is widespread in the industry. However, the dehydration processes lead to variable survival rates according to the group, species and strain of microorganism considered, but also according to the type of process used (drying, freeze drying, freezing). The plasma membrane (PM), by its position between the intra-and extracellular environment, is a target of hydric perturbations. Changes in this structure during hydric stresses are described to be directly involved in microorganism death. Understanding of membrane responses occurring during a dehydration/rehydration cycle is essential to maximize the survival of micr…
The syndrome "basses richesses" of sugar beet in France is associated with different pathogen types and insect vectors
2007
International audience; The syndrome “basses richesses” (SBR) of sugar beet in France is associated with two phloem-restricted uncultivable bacteria: a stolbur phytoplasma and a y-3 proteobacteria. The known vector of proteobacteria is a cixiid planthopper, Pentastiridius leporinus (Hemiptera Cixiidae), formerly shown to transmit both the prokaryotes. The role of P. leporinus and of two other planthopper species, Cixius wagneri and Hyalesthes obsoletus, in spreading the two pathogens to sugar beet were compared and quantified. Because of its abundance and high infection rates with proteobacterium, P. leporinus was confirmed to be the economic vector of SBR disease. P. leporinus and C. wagne…
Rôle de la membrane plasmique dans la survie des microorganismes à la déshydratation : Contribution à l’optimisation de procédés de conservation des …
2010
Cette synthèse est consacrée au rôle de la membrane plasmique des microorganismes, à travers ses évolutions structurales et fonctionnelles, dans la survie à la déshydratation. Elle comprend une première partie dans laquelle sont regroupés les principaux résultats portant sur l’influence de la déshydratation sur la survie microbienne, sur le comportement membranaire in situ et sur les mécanismes physiques de la déstabilisation membranaire. La deuxième partie est consacrée à la transposition de cette compréhension aux applications de déshydratation industrielle des microorganismes. Elle porte sur le développement d’un procédé de déshydratation des microorganismes et sur la mise au point d’out…
Influence of phytosterols on the structural and dynamic properties of plant plasma membrane
2008
National audience; The complex mixture of sterols, namely phytosterols, found in the plasma membrane (PM) of plant cells is an intriguing characteristic. In the present work, we characterized the sterol composition of tobacco BY-2 cell PM, and we adapted a sterol manipulation method to this plant material. Methyl-b-cyclodextrin was found to induce a drastic reduction of the PM total free sterol content, with a low specificity for the different phytosterols, and without effect on steryl-conjugates. The consequences of phytosterols depletion were investigated by means of fluorescence spectroscopy and biochemical detergent resistant membrane (DRM) fraction purification methods. Data obtained w…
Plasma membrane microdomains in plants: for which physiological roles?
2007
International audience; A large body of evidence supports the existence, in membrane from animal and yeast cells, of functional microdomains playing important roles in protein sorting, signal transduction, or infection by pathogens (1). We demonstrated the presence, in plants, of detergent resistant fractions isolated from plasma membrane, with a lipidic composition similar to animal microdomains (2). Electrophoresis experiments indicated that these fractions were able to recruit a specific set of plasma membrane proteins and exclude others. We used mass spectrometry to give an extensive description of a tobacco plasma membrane microdomains. This led to the identification of 145 proteins wh…
Characterization of membrane structure modifications induced during plant defense signaling
2017
SPEIPMUBINRADOCT; Plasma membrane was long considered as a simple separation between internal and external cellular environment. But more, it is a dynamic interface, an exchange platform. Now, recent researches highlight its role in plant defense responses to biotic and abiotic stresses. We use the tobaccocryptogein model to study the early steps of plant cell responses to pathogen detection. The signaling cascade includes an oxidative burst triggering an increase of plasma membrane order. The level of membrane order informs us about both packing and arrangement of membrane components, this parameter being evaluated by spectrofluorimetric approaches using a lipidic environment-sensitive pro…
Identification and diagnosis of patients with familial chylomicronaemia syndrome (FCS): Expert panel recommendations and proposal of an "FCS score".
2018
Familial chylomicronaemia syndrome (FCS) is a rare, inherited disorder characterised by impaired clearance of triglyceride (TG)-rich lipoproteins from plasma, leading to severe hypertriglyceridaemia (HTG) and a markedly increased risk of acute pancreatitis. It is due to the lack of lipoprotein lipase (LPL) function, resulting from recessive loss of function mutations in the genes coding LPL or its modulators. A large overlap in the phenotype between FCS and multifactorial chylomicronaemia syndrome (MCS) contributes to the inconsistency in how patients are diagnosed and managed worldwide, whereas the incidence of acute hypertriglyceridaemic pancreatitis is more frequent in FCS. A panel of Eu…
The mKdV equation and multi-parameters rational solutions
2021
Abstract N -order solutions to the modified Korteweg–de Vries (mKdV) equation are given in terms of a quotient of two wronskians of order N depending on 2 N real parameters. When one of these parameters goes to 0, we succeed to get for each positive integer N , rational solutions as a quotient of polynomials in x and t depending on 2 N real parameters. We construct explicit expressions of these rational solutions for orders N = 1 until N = 6 .
Expansion dynamics of the plasma plume formed by the impact of a nanosecond Nd : YAG laser beam on metallic surface under atmospheric conditions : ex…
2010
Laser ablation in the air at atmospheric pressure is nowadays frequently applied in industry, chemical analysis, surgery… For a further development of laser ablation based technologies, it is necessary to better understand the laser – matter interaction. During the impact of a laser pulse on the surface of the treated material, a plasma plume forms above the target surface. This plume contains particles (electrons, ions, atoms) of ablated matter, as well as of ambient gas, if present. During the laser pulse, this plume absorbs a large amount of the laser beam energy, thus reducing the quantity of the laser radiation arriving to the target surface. Dimensions, as well as parameters of this p…