Franca V. Sacchi

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A net absorption of sodium ions and ofl-phenylalanine, in the absence of chemical gradients, occurs across the isolated midgut of the cockroachBlabera gigantea. Both sodium and amino acid net fluxes were abolished by the haemolymphatic addition of the Na−K ATPase inhibitor ouabain, at a concentration 1 mM. A purified fraction of brush border membranes,(More)
Total extracellular space values have been determined in the midguts of 2 lepidopteran larvae, Philosamia cynthia and Bombyx mori. The values found are 42% and 45% tissue water respectively. Intracellular concentrations of Na+, Ca++ and Mg++ are very low, while K+ concentration is 197.2 mEq/l cell water in Philosamia and 180.9 mEq/l cell water in Bombyx.
A potassiumor sodium-activated cotransport of leucine occurs in brush-border membrane vesicles prepared from the midgut of larvae of Philosamia cynthia (Drury). The potassium chemical gradient can drive a twofold accumulation of leucine, which is greatly increased under experimental conditions that presumably provide an electrical potential difference(More)
Intermittent contact mode atomic force microscopy (AFM) was used to visualize the native plasma membrane of Xenopus laevis oocytes. Oocyte membranes were purified via ultracentrifugation on a sucrose gradient and adsorbed on mica leaves. AFM topographs and the corresponding phase images allowed for visualization and identification of both oocyte plasma(More)
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