Annales de la nutrition et de l'alimentation最新文献

The results presented in this paper establish relationships between structural, morphological and functional properties of cytoplasmic membrane vesicles isolated from an E. coli unsaturated fatty auxotroph. The membranes were isolated from cells grown in the presence of either oleic, linolenic or elaidic acids. High-angle X-ray diffraction studies show that order-disorder transitions induced by temperature variation sand associated with the hydrocarbon chains of the lipids are a function of the fatty acid composition of the membranes. In some cases, "cocrystallization" of various lipid species takes place within a single type of ordered domains. In other cases, there is a segregation of various lipid species into more than one distinct type of ordered domain. The various order-disorder transitions observed, induce morphological changes in the hydrophobic core of the membranes which can be detected by freeze-fracture electron microscopy. A random distribution of particles on the fracture faces is observed when the hydrocarbon chains of the lipids are disordered. Upon ordering of the hydrocarbon chains, particles are excluded from the ordered domains and as a consequence, smooth areas and areas with dense ly packed particles are observed. Discontinuities in the rate of energy-dependent beta-galactoside uptake as a function of temperature correlate with the order-disorder transitions observed. The increased slope of the Arrhenius representation in the temperature region of the transition is associated with the segregation of the carrier proteins excluded from the ordered membrane domains and their subsequent aggregation in the membrane domains containing the disordered lipids.

Appropriate adjustment of diet and specially reduction of the saturated fatty acids content is the cornerstone of correcting many hyperlipidemias. What we have tried in our study was first to show the evolution of the changes in the serum's fatty acids composition under a rich polyunsaturated fatty acids diet, second to find an index proving that the diet had correctly been taken. Chromatographic analysis were performed after ultracentrifugal separation of the lipoprotein fractions. Seven volunteers, non fat, and normolipemics were selected. Samples were collected every three or five days before and during the diet. The whole test lasted twenty days. What had been shown is that the linoleic acid content increased but the one of the oleic acid decreased in all lipoprotein fractions. Those changes are bestly illustrated by using the (formula: see text) ratio as a kinetic index. The triglycerid fraction modifications are faster than the phospholipid's one. Concerning the other fatty acids, the modifications are less spectacular : the palmitic acid decrease in every lipids fractions and the palmitoleic acid has a significant decrease only in the esterified cholesterol. And the stearic acid has no variation at least significatively.

In the last century, dense, pigmented bodies were observed on nerve cell sections, and the quantity of those pigments in the neurons was correlated to the age of the individual. Light microscopy has shown the presence of the pigments in the cells of most tissues and organs in both vertebrates and invertebrates, and they have also been seen in cultured cells. However, these commonly found cellular components have only have studied in detail since the last 25 years, using electron microscopic, histochemical and biochemical techniques to try to describe their nature, origin, development and possible physiological role. The comparable morphology, composition and physicochemical properties of these various pigments indicate that they are all produced by the same biochemical mechanism, including: 1) the peroxidation of the polyunsaturated fatty acids of cellular membranes by free radicals; 2) the reaction of lipid peroxidation end-products(s) with proteins, giving fluorescent polymerized compounds; 3) the combination of those polymerized elements and the peroxidized lipids. Different names have been used for these pigments, the most common of which in English are: "age pigment", "ceroid" and "lipofuscins". However, due to their common origin and their fluorescence, they are tended to be grouped under the term lipofuscins (in French: lipofuscines). Recent studies have confirmed that cellular lipofuscin concentration is definitely related to the physiological age of the individual. This concentration varies depending on the tissue and the organ; it is controlled by intrinsic regulatory factors, but also by environmental conditions, such as nutrition, physical activity, stress and hygienic conditions.

A quantitative study of feeding in Helix aspersa Müller (Gastropod, Pulmonate) is made in the laboratory with a view to apply the resulted obtained to its rearing in a warmed room. From the birth of the snails to six months old, two methods are applied: one ponderous, the other energetic, allowing us to draw up a nutritional budget. --The parameters are: daily rates of consommation, fecal production and assimilation; monthly production rate, efficiency of assimilation and finally gross and net growth efficiencies. The evolution of these parameters, seems to be dependant on the stage of growth of the snail, and on a physiological phenomenon present in Helix aspersa living in the field.

33 healthy men, 72 years old on average, ingested during five week: 2,4 g of Oenothera Biennis oil rich in PUFA. Before and after ingestion, platelet aggregation was measured according to the Born's photometric method, which divided the original group into two classes: "15" normal subjects (NAG) and "18" hyperagregated (HAG). The fatty acids contained in the serum were analysed by GLC. NAG liquid pattern did not show any difference after oil ingestion, as in HAG group, significant modifications were observed in palmitoleic, linoleic and linolenic fatty acid series. These observations probably correspond to a fundamental behavior difference, which might be related to desaturase activity reduction. Such a phenomenon would appear with ageing in some subjects. If this hypothesis is confirmed, the inclusion of the two methods of investigation described above would constitute a good approach for studying the enzymatic system activity in ageing.

In order to improve the digestibility of the Faba bean flour an hydrothermic enzymic and fermentation treatment has been thought out (US patent 395 8015, Ets Ury, M. Gay). This study aims at stemming out the nutritionnal and structural repercusions of this treatment on the Faba proteins. The nitrogen distribution is deeply changed : total nitrogen increase (47%), water soluble nitrogen decrease (41%), water soluble non-protein nitrogen increase. The treatment can enrich the flour in nitrogen but the proteins supplement is insoluble in water. The treatment changed the electrophoretic behaviour of flour proteins letting disappear precipitable pH 4,5 proteins. Amino acid composition is slightly changed, however there is an increase of lysine and methionine (15 et 25%) and a decrease of cysteine (28%). The chemical score shows sulfur amino acids and tryptophan deficiency. Enzymatic (pepsine and pancreatine mixture) liberation of all amino acids is low and is not improved by the treatment but for the lysine. Cell proteins supplement, which appeared during the treatment (61%), water insoluble, could improve nutritive value of the flour if a more complete destruction of the cell walls permitted their liberation and their solubilization.

The effects of coconut oil intake on fatty acid composition and plasma content of lipids have been investigated in Friesian preruminant male calves (3-weeks-old) 2 h (T2), 3 h (T3), 5 h (T5) and 7 h (T7) after the morning meal. Calves were fed for 21 days a milk replacer containing 21 p. 100 of dry matter which comprised tallow (diet T), or 2/3 tallow +1/3 coconut oil (diet A) or 1/3 tallow + 2/3 coconut oil (diet B). Compared with the data in the case of the conventional diet (diet T), plasma triglycerides (TG) and non esterified fatty acids (NEFA) concentrations were much higher with diet A (10 p. 100 C12 +C14 acids) and much lower with diet B (30 p. 100 C12 + C14 acids). Cholesteryl esters (CE) and phospholipids (PL) concentrations showed, at each sampling time, higher values with diets A or B. C12 and C14 acids were only present in plasma NEFA and TG with diets A and B. Saturation degree of plasma NEFA and TG was very high. It reached the highest value in the TG at T3 with diets T and A, at T5 with diet B. The fatty acids composition of plasma TG was only similar at T7 to that of feed TG (diet T, A or B). The fatty acid composition of plasma PL and especially CE was characterized, for the 3 diets, by the high level of polyunsaturated fatty acid proportions.

The influence of sodium oxalate and calcium oxalate upon calcium digestibility was studied in growing goats. Furthermore, and in the same animals, calcium absorption efficiency was estimated after performing duodenal fistula which allowed us to introduce calcium chloride or calcium oxalate and sodium oxalate, in order to avoid ruminal bacteria action upon the forementioned compounds. Finally, calcium absorption of an isolated intestine loop was studied in conscious goats with a Crocker Markowitz fistula, in the presence or absence of oxalate. The addition of sodium oxalate to the diet did not significantly decrease calcium absorption; but when calcium was given as oxalate, absorption was considerably lower. When calcium was introduced as calcium chloride through duodenal fistula, absorption was the same as when the substance was given in the diet. Calcium absorption drastically decreased when sodium oxalate was introduced directly into the duodenum, this fact is confirmed when calcium absorption is estimated in a jejunal loop, which shows that the differences found in relation to the effect of dietary sodium oxalate or directly introduced in duodenum are due to the substance destruction by ruminal bacteria.