Search results for "MESH : Spectroscopy"
showing 3 items of 3 documents
Mechanisms underlying the toxicity of lactone aroma compounds towards the producing yeast cells
2003
M. A G U E D O , L. B E N E Y , Y. W A C H EA N D J. - M. B E L I N. 2003. Aims: To study the fundamental mechanisms of toxicity of the fruity aroma compound c-decalactone, that lead to alterations in cell viability during its biotechnological production by yeast cells; Yarrowia lipolytica that is able to produce high amounts of this metabolite was used here as a model. Methods and Results: Lactone concentrations above 150 mg l )1 inhibited cell growth, depolarized the living cells and increased membrane fluidity. Infrared spectroscopic measurements revealed that the introduction of the lactone into model phospholipid bilayers, decreased the phase transition temperature. Moreover, the H + -…
Interaction of an odorant lactone with model phospholipid bilayers and its strong fluidizing action in yeast membrane
2003
International audience; Some odorant lactones are naturally present in fruits or in fermented products; they can also be used as food additives and can be produced by microorganisms at the industrial scale by biotechnological processes. Gamma-decalactone was previously shown to have antimicrobial properties. We determined by infrared spectroscopy measurements that this compound rapidly diffused into model phospholipid bilayers (within 2 min), modifying the general physical state of a dimyristoyl-L-alpha-phosphatidylcholine (DMPC) film. In vivo, the lactone strongly increased membrane fluidity in the model yeast Yarrowia lipolytica, as evaluated by fluorescence anisotropy measurements. This …
The shell matrix of the freshwater mussel Unio pictorum (Paleoheterodonta, Unionoida). Involvement of acidic polysaccharides from glycoproteins in na…
2007
13 pages; International audience; Among molluscs, the shell biomineralization process is controlled by a set of extracellular macromolecular components secreted by the calcifying mantle. In spite of several studies, these components are mainly known in bivalves from only few members of pteriomorph groups. In the present case, we investigated the biochemical properties of the aragonitic shell of the freshwater bivalve Unio pictorum (Paleoheterodonta, Unionoida). Analysis of the amino acid composition reveals a high amount of glycine, aspartate and alanine in the acid-soluble extract, whereas the acid-insoluble one is rich in alanine and glycine. Monosaccharidic analysis indicates that the in…