Localization of anionic constituents in mast cell granules of brachymorphic (bm/bm) mice by using avidin-conjugated colloidal gold

Abstract

We used the egg avidin gold complex as a polycationic probe for the localization of negatively charged sites in the secretory granules of mouse mast cells. We compared the binding of this reagent to mast cell granules in wild-type mice and in congenic brachymorphic mice in which mast cell secretory granules contained undersulfated proteoglycans. We localized anionic sites by post-embedding labeling of thin sections of mouse skin and tongue tissues fixed in Karnovsky's fixative and OsO4 and embedded in Araldite. Transmission electron microscopy revealed that the mast cell granules of bm/bm mice had a lower optical density than those of wild-type mice (P<0.001) and a lower adivin gold binding density (by approximately 50%, P<0.001). The latter result provides additional evidence that the contents of mast cell granules in bm/bm mice were less highly sulfated than in those of wild type mice. In both wild type and bm/bm mast cells, the distribution of granule equivalent volumes was multimodal, but the unit granule volume was approximately 19% lower in bm/bm cells than in wild type cells (P < 0.05). Thus, bm/bm mast cells develop secretory granules that differ from those of wild type mice in exhibiting a lower optical density and slightly smaller unit granules, however the processes that contribute to granule maturation and granule-granule fusion in mast cells are operative in the bm/bm cells.

The Use of Texture Analysis in the Morpho-Functional Characterization of Mast Cell Degranulation in Rainbow Trout (Onchorhynchus mykiss)

“…Basing upon the aforementioned consideration, a possible acidic (anionic) nature for the putative pro-contractile basophil agonist can be inferred. Anionic constituents in MC granules, ascribed to sulfated molecules, have been extensively studied by means of various polycationic probes (Skutelsky et al, 1995; Hammel et al, 2010). In human beings, sulphated glycosaminoglycans comprise the major supporting matrix of the MC granule and bind to histamine, proteinases, and acid hydrolases (He, 2004).…”

“…nature for the putative pro-contractile basophil agonist can be inferred. Anionic constituents in MC granules, ascribed to sulfated molecules, have been extensively studied by means of various polycationic probes Skutelsky et al, 1995;Hammel et al, 2010!. In human beings, sulphated glycosaminoglycans comprise the major supporting matrix of the MC granule and bind to histamine, proteinases, and acid hydrolases~He, 2004!. Interestingly, sulphated glycosaminoglycans, in particular heparin, are reported to enhance human uterine strip contractility and a patent application for establishing effective labor in women has been published~Ekman- Ordeberg & Malmström, 2008;Ekman-Ordeberg et al, 2009!.…”