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Biomedical subjects

C Monnier

Publications and source records attributed to C Monnier.

28 records · Page 2Linked to original sources

[Effect of the extrusion process on the availability of proteins].

The extrusion process has grown rapidly as in the preparation of meat-extenders from vegetal proteins as in the fabrication of cocktail-snacks and food for breakfast. The nutritional modifications induced by the thermic shock during the extrusion affect: -the diminution of the content of nutrient: loss in vitamins, destruction and unavailability of amino-acids; -the structural modification of a few compounds: starch gelatinization; -destruction of antinutritional factors: essentially antitrypsic factor. We studied the effect of extrusion with a model-mixture on the availability of amino-acids and particularly lysin. We effected the systematic study of different factors which can interfer in the intensity of the Maillard reaction in relation to the composition of the mixture (presence and nature of sugar, etc.) and to the technological parameters (screw-section, moisture of the mixture, etc.) The model mixture composed of cereal flours shows a global loss of 32 p. 100 in lysin (destruction 18 p. 100, biological unavailability 16 p. 100) after extrusion. When this mixture is added up with 7,2 p. 100 of saccharose the total loss in lysin reaches 40 p. 100. If saccharose is substituted by a more reducing sugar (fructose) the lysin loss approaches 80 p. 100. The addition of 4 p. 100 water at the mixture containing saccharose (total moisture 14 p. 100) limits the lysin loss to 10 p. 100. The modification of other technological parameters does not improve significatively the level of available lysin. The moisture of the mixture before extrusion appears to be a preponderatting factor in the intensity of the Maillard reaction during extrusion.

Amino Acids↗

Enzyme activities associated with an invertebrate iridovirus: nucleotide phosphohydrolase activity associated with iridescent virus type 6 (CIV).

A nucleoside triphosphate phosphohydrolase activity is firmly associated with a purified invertebrate iridovirus, iridescent virus type 6. The enzyme activity hydrolyzes all the nucleoside triphosphates, but has a high preference for ATP. The products of the reaction are nucleoside diphosphates. Conditions for nucleoside triphosphate phosphohydrolase activity are described.

Adenosine Diphosphate↗

Hypothesis: hyperstructures regulate bacterial structure and the cell cycle.

A myriad different constituents or elements (genes, proteins, lipids, ions, small molecules etc.) participate in numerous physico-chemical processes to create bacteria that can adapt to their environments to survive, grow and, via the cell cycle, reproduce. We explore the possibility that it is too difficult to explain cell cycle progression in terms of these elements and that an intermediate level of explanation is needed. This level is that of hyperstructures. A hyperstructure is large, has usually one particular function, and contains many elements. Non-equilibrium, or even dissipative, hyperstructures that, for example, assemble to transport and metabolize nutrients may comprise membrane domains of transporters plus cytoplasmic metabolons plus the genes that encode the hyperstructure's enzymes. The processes involved in the putative formation of hyperstructures include: metabolite-induced changes to protein affinities that result in metabolon formation, lipid-organizing forces that result in lateral and transverse asymmetries, post-translational modifications, equilibration of water structures that may alter distributions of other molecules, transertion, ion currents, emission of electromagnetic radiation and long range mechanical vibrations. Equilibrium hyperstructures may also exist such as topological arrays of DNA in the form of cholesteric liquid crystals. We present here the beginning of a picture of the bacterial cell in which hyperstructures form to maximize efficiency and in which the properties of hyperstructures drive the cell cycle.

Bacteria↗