Food proteins and maturation of small intestinal microvillus membranes (MVM). III. Food protein binding and MVM proteins in rats from newborn to young adult age.

To investigate postnatal maturational profiles of functional and biochemical properties of rat small intestinal microvillus membranes (MVM), we did a longitudinal study in rats from birth to the age of 12 weeks. In parallel, we studied binding of cow's milk proteins and of the wheat gliadin peptide B 3142, as well as MVM proteins (SDS-PAGE). Changes in MVM fluidity and lipid composition exhibited early (0-4 weeks) and intermediate and late (6-12 weeks) patterns, as has been published earlier.

Neonatal and adult patterns of lectin binding to rat small intestinal microvillus membranes.

To investigate postnatal developmental changes of rat small intestinal microvillus membrane (MVM) sugar components, binding studies were done using peanut agglutinin (PNA) and soybean agglutinin (SBA). MVM were prepared from rats of different ages (new-borns to 12 weeks). The Airfuge method was used for separation of unbound material.

Handling of gliadin peptides B1-B4 and of cow's milk proteins by rat jejunum gut sacs.

The rat everted gut sac was used as a model of intestinal protein and peptide handling to study small intestinal binding and uptake of different gliadin peptide fractions (B1, B2, B3, B4) in comparison with bovine serum albumin (BSA), alpha-lactalbumin (alpha-LA), and a BSA peptide fraction (BSA-P). Not only binding curves, but also uptake curves of BSA, alpha-LA, and BSA-P were run in parallel between 1 and 30 min. Binding and uptake obviously depended on molecular weight.

Food proteins and maturation of small intestinal microvillus membranes (MVM). II. Binding of gliadin hydrolysate fractions and of the gliadin peptide B3142.

To investigate in vitro interactions between gliadin peptide fractions that have been shown to be toxic to celiac small intestinal mucosa in humans and small intestinal microvillus membranes (MVM) from rats during postnatal maturation, MVM were prepared from newborn, 18-day-old preweanling, and adult rats. Partially hydrolyzed gliadin peptide fractions B1-B4, and the pure gliadin peptide B3142 were radioiodinated and used for binding assays. Miniature ultracentrifugation was used for separation of unbound material.

Food proteins and maturation of small intestinal microvillus membranes (MVM). I. Binding characteristics of cow's milk proteins and concanavalin A to MVM from newborn and adult rats.

To study maturational changes of food protein and lectin binding to rat small intestinal microvillus membranes (MVM), MVM were prepared from newborn and adult animals by a modified CaCl2 precipitation technique. Radiolabeled cow's milk proteins [alpha-lactalbumin, alpha-casein, beta-lactoglobulin, bovine serum albumin (BSA)] and the lectin concanavalin A (Con A) were used for incubations. Binding assays were done using miniature ultracentrifugation for separation of unbound material.