Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

M cells in Peyer's patch follicle epithelium endocytose and transport luminal materials to intraepithelial lymphocytes. We examined (1) enzymatic characteristics of the epithelium covering mouse and rat Peyer's patches by using cytochemical techniques, (2) distribution of lectin-binding sites by peroxidase-labeled lectins, and (3) anionic site distribution by using cationized ferritin to develop a profile of M cell surface properties. Alkaline phosphatase activity resulted in deposits of dense reaction product over follicle surfaces but was markedly reduced over M cells, unlike esterase which formed equivalent or greater product over M cells. Concanavalin A, ricinus communis agglutinin, wheat germ agglutinin and peanut agglutinin reacted equally with M cells and with surrounding enterocytes over follicle surfaces. Cationized ferritin distributed in a random fashion along microvillus membranes of both M cells and enterocytes, indicating equivalent anionic site distribution. Staining for alkaline phosphatase activity provides a new approach for distinguishing M cells from enterocytes at the light microscopic level. Identical binding of lectins indicates that M cells and enterocytes share common glycoconjugates even though molecular groupings may differ. Lectin binding and anionic charge similarities of M cells and enterocytes may facilitate antigen sampling by M cells of particles and compounds that adhere to intestinal surfaces in non-Peyer's patch areas.
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PMID:Cytochemical analysis of alkaline phosphatase and esterase activities and of lectin-binding and anionic sites in rat and mouse Peyer's patch M cells. 665 Apr 35

The outer and inner bilayers of the apical membrane complex of Schistosoma mansoni were sequentially stripped from adult worms by two incubations in 0.1% digitonin solutions. Membrane removal was evaluated by electron microscopy of worms and bilayer material, using Con A-ferritin as a marker for the outer bilayer. Amounts of Con A removed by the digests were measured with a tritiated Con A marker. To measure the purity of the fractions membrane markers were characterised and quantitated for both bilayers. In the absence of the usual enzymatic markers for plasma membrane diazotised [125I]-iodosulfanilic acid was used as a marker for the outer bilayer. Alkaline phosphatase and a Na+, Mg2+-ATPase were localised to the inner bilayer. From these results we can deduce that the inner bilayer is analogous to the typical, apical plasma membrane of other animal epithelia. The outer bilayer does not share these enzymatic similarities. The integrity of the syncytium after removal of the outer bilayer and the increased levels of lactate dehydrogenase in the supernatant after removal of the inner bilayer suggests that the outer bilayer is secondary in maintaining the permeability barrier of the apical membrane complex, with respect to soluble proteins. The possible significance of these results in terms of the destructive action of complement on the parasite are discussed.
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PMID:Sequential removal of outer bilayer and apical plasma membrane from the surface epithelial syncytium of Schistosoma mansoni. 685 11

In this study, we show that superoxide production is carried out within intracellular compartments of human neutrophils and not at the plasma membrane following stimulation with phorbol myristate acetate. Oxidant production was not observed in unstimulated cells. Stimulated cells exhibited superoxide production in two distinct types of intracellular organelles. Initially, activity was detected in slender rod-shaped granules and in spherical or elliptical granules. The oxidant-producing granules fused directly with the plasma membrane or fused to form larger intracellular vesicles which then became associated with the plasma membrane. Longer periods of stimulation with PMA resulted in a decrease in the number of vesicles containing oxidant reaction product only, and an increase in structures containing both the oxidant-reaction product and ferritin particles; the latter was used herein as a marker for endocytosis. Thus a complex pattern of intracellular vesicular trafficking occurs in stimulated neutrophils. Alkaline phosphatase activity, a marker enzyme for a type of intracellular neutrophil granule was co-localized in the oxidant reaction-positive intracellular compartments. The time course of up-regulation of alkaline phosphatase activity to the cell surface parallelled the release of superoxide from stimulated cells. Results from this study demonstrate for the first time cytochemical and morphological evidence that superoxide is released from stimulated neutrophils through exocytosis of an oxidant-producing intracellular granule.
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PMID:Identification of intracellular sites of superoxide production in stimulated neutrophils. 939 14