Search results for "granules"
showing 10 items of 45 documents
An Ovalbumin Peptide-Specific Cytotoxic T Cell Clone with Antigen Self-Presentation Capacity Uses Two Distinct Mechanisms to Kill Target Cells
1993
Abstract Cloned 10BK.1 T cells with specificity for the ovalbumin peptide OVA257-264 are representative of a novel cell type within the CD8 + subset of T cells. In the presence and in the absence of added antigen presenting cells these T cells react toward antigen (Ag) by proliferation and lymphokine production. These data suggest self-presentation of the Ag by 10BK.1 cells. Here we present evidence that 10BK.1 cells exhibit cytotoxic activity that involves two different cytotoxic effector mechanisms. (i) One mechanism is fast killing activity, apparent within 4 hr. Constitutive mouse T cell-specific proteinase-1 (MTSP-1) activity, constitutive expression of MTSP-1 RNA, increased by Ag chal…
Quantitative electron microscopic observations on Paneth cells of germfree and ex-germfree Wistar rats.
1986
Ultrastructural changes of Paneth cells of germfree (Gf) rats which had been inoculated with bacteria-containing feces from conventionally-reared (SPF) rats were quantitatively examined. 12 and 24 h after inoculation, the Paneth cells showed a striking decrease in the number of secretory granules and the occurrence of large vacuoles. Phagosomes containing bacteria were not seen. After 4 days, the secretory granules reaccumulated and smooth-surfaced apical vesicles increased in number. It is discussed that the large vacuoles may be related to membrane-retrieval events following the massive extrusion of secretory granules whereas the apical vesicles appear to serve this function when exocytos…
Encapsulation Response ofCiona intestinalis(Ascidiacea) to Intratunical Erythrocyte Injection
1997
Abstract Electron microscopic studies on the encapsulation induced by erythrocyte injection into the tunic of the ascidian Ciona intestinalis were carried out. The observations reported in the present paper complete the description previously given of capsule architecture and contribute to the characterization of the cells involved in the inflammatory reaction. The inflamed area is surrounded by an ample and peculiar “three-layered coat” respectively composed of flattened and packed extratunical hemocytes, the monolayered epithelium, and a layer of intratunical electron-dense particles. The latter are also clustered, variously arranged, and distributed in the tunic ground substance. The epi…
Activation of oligodendroglial Fyn kinase enhances translation of mRNAs transported in hnRNP A2-dependent RNA granules.
2008
Central nervous system myelination requires the synthesis of large amounts of myelin basic protein (MBP) at the axon–glia contact site. MBP messenger RNA (mRNA) is transported in RNA granules to oligodendroglial processes in a translationally silenced state. This process is regulated by the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 binding to the cis-acting A2 response element (A2RE). Release of this repression of MBP mRNA translation is thus essential for myelination. Mice deficient in the Src family tyrosine kinase Fyn are hypomyelinated and contain reduced levels of MBP. Here, we identify hnRNP A2 as a target of activated Fyn in oligodendrocytes. We show that…
Heterogeneous nuclear ribonucleoprotein (hnRNP) F is a novel component of oligodendroglial RNA transport granules contributing to regulation of myeli…
2011
Myelin basic protein (MBP) is a major component of central nervous system (CNS) myelin. The absence of MBP results in the loss of almost all compact myelin in the CNS. MBP mRNA is sorted into RNA granules that are transported to the periphery of oligodendrocytes in a translationally inactive state. A central mediator of this transport process is the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 that binds to the cis-acting A2-response element in the 3′UTR of MBP mRNA. Recently, we found that activation of the Src family nonreceptor tyrosine kinase Fyn in oligodendrocytes leads to phosphorylation of hnRNP A2 and to increased translation of MBP mRNA. Here, we identify…
Differential staining of mucin granules from epoxy resin sections by a phosphotungstic acid-methyl green procedure.
1991
After treatment of epoxy resin semithin sections from glutaraldehyde fixed rat large intestine with 5% aqueous phosphotungstic acid (PTA), staining with unpurified 0.2% solutions of methyl green at 60 C for 5 min produces a color differentiation between mucin granules of goblet cells. Some mucin granules and the glycocalyx appear deep green while the remaining granules, luminal mucin and collagen fibers are pink. The known contamination of unpurified methyl green with crystal violet seems to be responsible for the pink staining reaction of the latter structures, which also present an orange-red fluorescence under green exciting light. Electron microscopic observations show selective contras…
Isolation and expression of a novel MBL-like collectin cDNA enhanced by LPS injection in the body wall of the ascidian Ciona intestinalis
2009
Collectins are a family of calcium-dependent lectins that are characterized by their collagen-like domains. Considerable interest has been focused on this class of proteins because of their ability to interact with components of the complement system activating a cascade of events responsible for the activation of the innate immune system. A differential screening between LPS-challenged and naïve Ciona intestinalis has been performed allowing the isolation of a full length cDNA encoding for a 221 AA protein. In silico analysis has shown that this polypeptide displays protein domains with similarities to mannose-binding lectins. A phylogenetic analysis suggested that C. intestinalis MBL has …
Metachromatic staining and electron dense reaction of glycosaminoglycans by means of Cuprolinic Blue
1987
The cationic phthalocyanin-like dye Cuprolinic Blue, unlike phthalocyanin dyes such as Alcian Blue or Astra Blue, can definitely exhibit a clear metachromatic reaction with appropriate substrates. The application of Cuprolinic Blue to epoxy-embedded semithin sections revealed that mast cell cytoplasmic granules, goblet cell mucin and cartilage matrix stained in violet shades (metachromatic), whereas nuclear chromatin presented a bright blue coloration (orthochromatic). The metachromatic structures showed a high degree of contrast when ultrathin sections treated with Cuprolinic Blue were examined by electron microscopy. Cytophotometric measurements of stained components from the large intest…
A barium method for the cytochemical detection of sulfated glycosaminoglycans in mast cells and basophilic leukocytes.
1999
Barium ions precipitate inorganic as well as organic sulfate compounds and they can be detected by a reaction with sodium rhodizonate. In this work, we describe the use of a barium method for the selective demonstration of sulfated glycosaminoglycans in cytoplasmic granules of mast cells and basophilic leukocytes. Methanol-fixed smears of mouse peritoneal mast cells and rat bone marrow basophils were treated with 5% BaCl2 for 10 min, followed by staining with either 0.2% sodium rhodizonate in 50% ethanol for 2 h at 60 degrees C, or 0.01% brilliant green in distilled water for 1 min. Light microscopic observation revealed a strong staining reaction of the cytoplasmic granules of these cell t…
Esthesioneuroblastoma: Ultrastructural, immunohistological and biochemical investigation of one case
1984
A case of esthesioneuroblastoma, the pathological diagnosis of which almost always causes great difficulties, was investigated ultrastructurally, biochemically, and immunohistologically, using antibodies against the five known types of intermediate filaments [keratin, vimentin, desmin, glial fibrillary acidic protein (GFAP) and neurofilaments]. The tumour cells did not react with antibodies against any of the five intermediate filament proteins. Ultrastructural investigations showed dense cored secretory granules in the cytoplasm and cell processes. Thus, immunohistology offers by "exclusion" a differential diagnosis to avoid often misdiagnosed tumours (undifferentiated carcinomas, embryona…