John T. Albright

The ultrastructure of the swimbladder of the toadfish, Opsanus tau L.

SummaryThe anterior chamber of the swimbladder of the toadfish Opsanus tau L. is lined by a single layer of columnar gas gland cells, cuboidal cells that resemble gas gland cells but are located outside of the gas gland region, and squamous cells. Multilamellar bodies are numerous in the gas gland cells and the cuboidal cells and are present in smaller numbers in the squamous cells. Capillaries lie in the lamina propria directly below the epithelial lining. A thick continuous muscularis mucosae and a submucosa consisting of tightly packed cells, cell processes, and connective tissue may contribute to the impermeability to gases of the wall of the anterior chamber.The posterior chamber of the swimbladder is lined by a single type of squamous epithelial cell. Multilamellar bodies were occasionally observed in these cells also. Other types of cells frequently form a partial second layer between the epithelial lining and the basement lamina. A thin muscularis mucosae lies directly below the basement lamina and the capillaries of the posterior chamber are located in the submucosa. The tunica externa is a layer of dense connective tissue that surrounds both the anterior and posterior chambers. Collagen fibrils in the form of tactoids are present in this layer.

Superoxide dismutase, catalase, and glutathione peroxidase in the swim bladder of the physoclistous fish, Opsanus tau L

SummaryThe antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase were measured in the rete mirabile and gas gland epithelium area of the swim bladder of the toadfish Opsanus tau. When the concentration of enzyme in the swim bladder was compared with the concentration in other organs (kidney, heart, gills) of the same fish, the swim bladder was found to have the highest concentration of superoxide dismutase but relatively low levels of glutathione peroxidase and catalase.Cytochemical assay for the peroxidatic activity of catalase confirmed that virtually no catalase is present in epithelial cells of the gas gland. A similar assay for peroxidase revealed a cyanide-sensitive peroxidase in the multilamellar bodies of these cells. Most of the catalase and peroxidase in the rete mirabile appears to be confined to the granules of neutrophils and the cytoplasm of erythrocytes. Enzyme activity in the neutrophils is not inhibited by 10-1 M KCN. Cyanide does appear to inhibit the peroxidase activity in erythrocytes but has little effect on catalase in these cells.

The effects of acetic acid and pepsin on the crosslinkages and ultrastructure of corneal collagen

Abstract Corneal collagen is shown to contain several of the well known lysine-derived crosslinks. NaBH4 reduction of acid-soluble corneal collagen revealed the reduced aldol-condensation product of two residues of allysine and an unknown component referred to as the pre-hydroxylysine component. The reconstituted fibrils contain hydroxylysinonorleucine and histidinohydroxymerodesmosine. Pepsin treatment of insoluble corneal tissue at 4 °C in 0.5 M acetic acid results in 60–70% solubilization of collagen; however, data obtained suggest the solubilized collagen has been altered in the non-helical terminal regions. Abnormal ribbon-like segment long spacing monomers are formed rather than normal segment long spacing fibrils and chemical reduction reveals complete loss of the pre-hydroxylysine component and hydroxylysinonorleucine. Significant losses of aldol-condensation product and histidinohydroxymerodesmosine occur with increasing duration of pepsin treatment. As demonstrated by electron microscopy the insoluble corneal collagen remaining after acetic acid extraction has no fibrous structure. In addition lysine-derived crosslinks are not detected by NaBH4 reduction. After dialysis of the insoluble residue against 0.15 M NaCl (pH 7.5) normal collagen fibers together with intermolecular crosslinks appear.

Ultrastructure of the swim bladder of the goldfish, Carassius auratus.

SummaryThe swim bladder of the cyprinid Carassius auratus (goldfish) is a two-chambered organ connected to the esophagus by a pneumatic duct. The anterior chamber is lined by a single type of squamous epithelial cell. Two types of epithelial cells are present in the posterior chamber. Flattened cells with differences in the electron density of the cytoplasm line most of the chamber. Darker cells generally contain large amounts of glycogen. Cuboidal epithelial cells also occur in the posterior chamber. A glandular layer external to the muscularis in the posterior chamber is composed of large cells containing little glycogen, an extensive Golgi apparatus, and numerous mitochondria with single large granules. Capillaries and nerves are present in large numbers in this layer. Blood vessels form micro-retia mirabilia in the submuscular layer external to the glandular layer. Vessels are of two distinct types with wide lumina and flattened endothelium characterizing the venous vessels. Arterial vessels have smaller lumina, thick endothelial cells with prominent pinocytotic vesicles, and surrounding pericytes. Collagen is present in three forms in this swim bladder — large tactoids in the tunica externa of the anterior chamber, smaller tactoids in the lamina propria of the posterior chamber, and small fibrils in all other areas.

Continued study of the ultrastructure of the gingiva in the diabetic mouse

Abstract A continued study of gingival biopsies from the Jackson strain diabetic mouse revealed not only an amorphous thickening of the basement membranes of the blood vessels, but also a lamellar thickening. The normal control blood vessels had basement membrane widths in the 2000-A range, whereas the diabetic animals exhibited an average width of 8000 A. These changes were significant at the 0.1% level. Other changes seen in our studies were: (1) an alteration in the endothelial lining of the blood vessels which appeared as an increase in pseudopod or flap formation on the luminal side, and (2) the appearance of large dense bodies within the epithelial cell mitochondria in the mouse which to our knowledge has not been previously described.

The ultrastructure of the gingiva in the diabetic mouse.

Abstract In order to further clarify the morphologic changes which occur in the gingiva and the nature of the transendothelial passage of nutrients across the vessel walls, gingival biopsies from the incisor area of Jackson strain mice were examined. Our initial investigations revealed the following changes in the diabetic animals: (1) a marked increase in keratohyalin granules in the stratum granulosum and (2) an apparent thickening of the basement membrane of the gingival blood vessels which ranged from 2000–6000 A. Statistical evaluation of these changes is currently underway.

Ultrastructure of a new cell in the gills of the air-breathing fish Helostoma temmincki

A cell which has not been previously described was observed in the gills of Helostoma temmincki . This cell contains long mitochondria, over 3 μ , in parallel array, surrounded by an extensive system of coated channels. There is a 200 A space between the membranes of the mitochondria and the channels. The particles coating the channels are seen in the center of this space. These particles are about 80 A in diameter with 60 A spaces between them. A connection is sometimes seen between the membranes of the channels and the particles. The close association between mitochondria and the coated channels is a characteristic of cells thought to be functioning in the active transport of ions and water. This morphological similarity to other transport cells, and additional experiments in which the specimens were subjected to gradients of hypertonic and hypotonic water, suggest that this cell also functions in the active transport of a substance.

Ultrastructure of the gingiva of rabbits

Abstract The gingival sulcus wall of Dutch Belted rabbits was used to study vascular transudation and exudation with Pelikan ink as a tracer for light microscopy and saccharated iron oxide as an electron microscopic tracer. The marker was apparently transported by numerous plasmalemmal vesicles, and also passed through the interendothelial junctions. The sulcular fluid was an inflammatory exudate rather than a transudate. Ultrastructural alterations of the gingiva following inflammation were studied. The interepithelial space increased more on the sulcular than the attached gingival side. The wider interepithelial space in the sulcular area and the non-keratinizing nature of this tissue may have contributed to the ease of passage of the gingival fluid in that region.