Glycoconjugates on the Surface of the Pulmonary Epithelial Cells in Surfactant Free Rat Lungs

Glycoconjugates on the cell surface of type I and type II pulmonary epithelial cells were examined after airway irrigation by means of colloidal iron (CI), high iron diamine (HID) and ferritin-conjugated lectin stainings, in combination with digestion with carbohydrate-degrading enzymes, methylation or extraction with acid ethanol. The acid saccharide on the surface of type I cells was sialic acid, but the surface of type II cells contained a mixture of a large amount of sialic acid and a small amount of sulfated saccharide. As to the sensitivity on acid ethanol extraction, the sialo-oligosaccharide on type I cells differed from that on type II cells, although the terminal trisaccharides of sialo-oligosaccharides on the both type I and II cells were sialic acid → galactose → N-acetylgalactosamine. Sulfated saccharide, being mainly composed of glucuronic acid and N-acetylgalactosamine, distributed on the surface of the microvilli of type II cells. As to the constituents of glycoconjugates, large amounts of N-acetylglucosamine, galactose, mannose and glucose were found on type I cells, but type II cells had only small amounts of N-acetylglucosamine, mannose and glucose, and a minute amount of galactose

Seven Kinds of Intermediate Filament Networks in the Cytoplasm of Polarized Cells: Structure and Function

Intermediate filaments (IFs) are involved in many important physiological functions, such as the distribution of organelles, signal transduction, cell polarity and gene regulation. However, little information exists on the structure of the IF networks performing these functions. We have clarified the existence of seven kinds of IF networks in the cytoplasm of diverse polarized cells: an apex network just under the terminal web, a peripheral network lying just beneath the cell membrane, a granule-associated network surrounding a mass of secretory granules, a Golgi-associated network surrounding the Golgi apparatus, a radial network locating from the perinuclear region to the specific area of the cell membrane, a juxtanuclear network surrounding the nucleus, and an entire cytoplasmic network. In this review, we describe these seven kinds of IF networks and discuss their biological roles

Ganglion Cell Differentiation and Intermediate Filaments in the Cervical Dorsal Root Ganglion of the Chick Embryo

To examine the differentiation processes of cervical dorsal root ganglionic cells, vimentin, nestin and neurofilament-H protein were immunohistochemically detected in chick embryos from stages 15 through 43. During stages 15-17, migrating neural crest cells exclusively expressed vimentin. At stage 20, there was a marked decrease in vimentin, and appearance of nestin in most cells of the ganglionic primordia. However, a few Schwann precursor cells containing only vimentin were also observed. During stages 24-26, spindle-shaped precursors of pseudounipolar neurons containing neurofilament-H protein increased in number in the primordia of the ganglia. During stages 28-30, large round immature neurons containing neurofilament-H protein in both their perikaryon and neurites were recognized. At stage 36, the neurons contained neurofilament-H protein and transiently vimentin. In addition, the precursors of satellite cells, containing neither vimentin, nestin, nor neurofilament-H protein, could be observed around the neurons. At stage 43, three mature cell types could be distinguished; pseudounipolar neurons containing neurofilament-H protein, Schwann cells containing vimentin, and satellite cells containing neither vimentin, nestin, nor neurofilament-H protein. These results clearly demonstrate that differentiation of neural crest cells into neurons, Schwann cells and satellite cells, is reflected by the intermediate filament composition