Uptake of exogenous protein tracer in cells of the rat renal papilla

In order to study the phagocytic potential of different cell types of the rat renal papilla with special emphasis on interstitial cells, horseradish peroxidase (HRP) (8 mg/100 g body weight) was injected intravenously into adult rats. The distribution of peroxidase was studied in animals perfusion-fixed 60 and 180 min after injection and was found to be similar after both time intervals. The epithelial cells of the collecting ducts took up the largest amounts of the tracer. HRP was mainly located in large lysosome-like bodies in the basal part of the cytoplasm, suggesting peritubular uptake from the interstitial space. However, small amounts of the tracer were also seen in apical vesicles close to the luminal plasma membrane. The interstitial cells of peroxidase-injected animals were ultrastructurally altered and had large irregular invaginations of the cell membrane. The cells had taken up only small amounts of the tracer which were located in small round lysosome-like bodies. Thus, the interstitial cells displays no macrophage characteristics, either in the native state or when challenged with an extracellular protein.     

Ultrastructure of the interstitial cells of the renal papilla in the white rat

Interstitial cells of the renal papilla have the phenotypic appearance, being more of a fibroblast than of a histiocyte character. Interstitial cells differ from the "typical fibroblasts" in the number of lipid droplets, in the development of cisternae of the Golgi complex and rough endoplasmic reticulum, and in the number of lysosome-like bodies and mitochondria.     

Uptake and metabolism of exogenous glycosphingolipids by cultured cells

Exogenous glycosphingolipids, especially gangliosides, are used to study transport and metabolism of their endogenous counterparts as well as their role in cell adhesion, cell recognition and signal transduction. Unlike monodispersed solutes, in aqueous media ganglioside molecules aggregate into micelles (or bilayer structures) with a very low critical micellar concentration. Upon addition to cells in culture, exogenous gangliosides bind to the cell surface in three operationally defined modes: loosely associated micelles removable by serum; tightly attached micelles removable by proteases such as trypsin; and ganglioside molecules inserted into the outer leaflet of the plasma membrane. As shown by a biotin-labeled derivative of the ganglioside GM1 these inserted molecules are endocytosed and transported to intralysosomal membranes for catabolism. The benefit from using (partially) nondegradable as well as semi-truncated glycosphingolipids in transport studies is discussed.     

Uptake of l-Dopa by cells in the taste buds of the vallate papilla of the mouse

Summary Several precursor substances and biogenic amines were admistered intraperitoneally to mice and were examined by the histochemical formaldehyde induced fluorescence method. It was found that after treatment with l-Dopa a number of cells inside the taste buds showed fluorescence.     

Uptake of exogenous DNA by pea seedlings and tobacco cells

1.

(1) The uptake of Pseudomonas aeruginosa DNA by pea seedlings, and uptake of tobacco DNA or P. aeruginosa DNA by tobacco cells in shake cultures has been investigated. The fate of the DNA has been followed by CsCl density gradient equilibrium centrifugation, using radiolabeled donor DNA of high density.     

The volume and ionic composition of cells in incubated slices of rat renal cortex, medulla and papilla

The apparent extracellular space in incubated slices of rat renal cortex, medulla and papilla has been measured using three differently sized marker molecules, mannitol, sucrose and inulin. Cellular volumes have been estimated by following the efflux of from equilibrated slices. Sucrose appears to be the most accurate extracellular marker in each of the regions examined, in that the sum of its volume of distribution plus cellular volume approximates most closely to the total slice fluid volume. Inulin has the same volume of distribution as sucrose in cortical slices, but under-penetrates medullary and papillary tissue. Mannitol overestimates the extracellular space in all three regions, although its larger volume of distribution, relative to that of sucrose, was not statistically significant in papillary slices. When cell volume and composition are estimated (a) using sucrose as extracellular marker and (b) making appropriate allowance for the presence of bound tissue electrolytes, it is found that cells in each region have low Na⁺ and high K⁺ concentrations and contents. When papillary slices are incubated in medium of very high osmolality (NaCl plus urea, 2000 mosmol/kg H₂O) there is a moderate (approx. 23%) decrease in cell volume and an increase in cell fluid Na⁺ and Cl⁻ concentrations equal to approx. 50% of the increase in the extracellular concentrations. Cell K⁺ concentrations remain unchanged. The results show that cells in renal slices are able to maintain high K⁺-to-Na⁺ ratios when incubated in isosmotic (cortex) or moderately hyperosmotic media (medulla and papilla), and suggest that regulation of papillary cell volume following hyperosmotic shock can only partly be ascribed to uptake of extracellular electrolytes.     

The volume and ionic composition of cells in incubated slices of rat renal cortex, medulla and papilla

The apparent extracellular space in incubated slices of rat renal cortex, medulla and papilla has been measured using three differently sized marker molecules, mannitol, sucrose and inulin. Cellular volumes have been estimated by following the efflux of 3-O-methyl-D-glucose from equilibrated slices. Sucrose appears to be the most accurate extracellular marker in each of the regions examined, in that the sum of its volume of distribution plus cellular volume approximates most closely to the total slice fluid volume. Inulin has the same volume of distribution as sucrose in cortical slices, but under-penetrates medullary and papillary tissue. Mannitol overestimates the extracellular space in all three regions, although its larger volume of distribution, relative to that of sucrose, was not statistically significant in papillary slices. When cell volume and composition are estimated (a) using sucrose as extracellular marker and (b) making appropriate allowance for the presence of bound tissue electrolytes, it is found that cells in each region have low Na+ and high K+ concentrations and contents. When papillary slices are incubated in medium of very high osmolality (NaCl plus urea, 2000 mosmol/kg H2O) there is a moderate (approx. 23%) decrease in cell volume and an increase in cell fluid Na+ and Cl- concentrations equal to approx. 50% of the increase in the extracellular concentrations. Cell K+ concentrations remain unchanged. The results show that cells in renal slices are able to maintain high K+-to-Na+ ratios when incubated in isosmotic (cortex) or moderately hyperosmotic media (medulla and papilla), and suggest that regulation of papillary cell volume following hyperosmotic shock can only partly be ascribed to uptake of extracellular electrolytes.     

Immunohistochemical localization of a protein fraction derived from rabbit renal papilla

Studies were carried out to define antigenic characteristics of the rabbit renal collecting duct. Renal papillae of adult rabbits were homogenized, centrifuged, and the 600 X g pellet was extracted with 0.5% Triton X-100 in the presence of 1 M NaCl. The crude extract was fractionated on an anion exchange column (DEAE cellulose). A fraction enriched in acidic proteins that co-purified with a radioactive 150 kd glycoprotein from cultured collecting duct cells (Minuth 1982), was used for immunization of guinea pigs. The antiserum shows the following characteristics as revealed by indirect immunofluorescence on the rabbit kidney: 1) Among all tubular epithelial cells only principal cells of the collecting duct and the connecting tubule cell show immunoreactivity. 2) The antiserum decorates the epithelial-interstitial interface of the whole collecting duct as well as of connecting tubule and thick ascending limb of Henle's loop. 3) There is immunoreactivity of interstitial fibers throughout the kidney. 4) Epithelial cells in a variety of other organs in rabbit did not react with the antiserum. Our data demonstrate an antigenic distinction of both, the connecting tubule cell and the principal cell, discriminating these cells from other tubular epithelial cells including the intercalated cells of the collecting duct system. Furthermore, our findings point to a heterogeneity along the distal nephron with respect to the constituents of the epithelial-interstitial interface.     

Differential and morphogenetic potential of rat dermal papilla cells

Dermal papilla (DP) cells were isolated from rat vibrissae and put into a culture. The homogeneity of the obtained culture was confirmed using immunohistochemical staining with antibodies specific for this type of cell extracellular matrix protein (versican) and staining for alkaline phosphatase. It was demonstrated that the rat vibrissae DP cell culture participates in the development of hair follicles de novo. The ability of the DP culture cells to differentiate in neurons and glia was proved.     

Immunohistochemical localization of a protein fraction derived from rabbit renal papilla

Summary Studies were carried out to define antigenic characteristics of the rabbit renal collecting duct. Renal papillae of adult rabbits were homogenized, centrifuged, and the 600×g pellet was extracted with 0.5% Triton X-100 in the presence of 1 M NaCl. The crude extract was fractionated on an anion exchange column (DEAE cellulose). A fraction enriched in acidic proteins that co-purified with a radioactive 150 kd glycoprotein from cultured collecting duct cells (Minuth 1982), was used for immunization of guinea pigs. The antiserum shows the following characteristics as revealed by indirect immunofluorescence on the rabbit kidney: 1) Among all tubular epithelial cells only principal cells of the collecting duct and the connecting tubule cell show immunoreactivity. 2) The antiserum decorates the epithelial-interstitial interface of the whole collecting duct as well as of connecting tubule and thick ascending limb of Henle's loop. 3) There is immunoreactivity of interstitial fibers throughout the kidney. 4) Epithelial cells in a variety of other organs in rabbit did not react with the antiserum.Our data demonstrate an antigenic distinction of both, the connecting tubule cell and the principal cell, discriminating these cells from other tubular epithelial cells including the intercalated cells of the collecting duct system. Furthermore, our findings point to a heterogeneity along the distal nephron with respect to the constituents of the epithelial-interstitial interface.     

Alpha-gustducin-immunoreactive solitary chemosensory cells in the developing chemoreceptorial epithelium of the rat vallate papilla

The presence of solitary chemosensory cells was studied in rat vallate papillae during the first week of post-natal life by alpha-gustducin immunocytochemistry. In 1- to 3-day-old rats, isolated alpha-gustducin-immunoreactive cells were found within the epithelium of the vallate papilla. These cells, mainly located in the basal layer, were scattered among keratocytes and wrapped in alpha-gustducin-negative epithelial cells in a glia-like fashion. The alpha-gustducin-immunoreactive cells were usually round and some of them gave rise to short, large processes directed towards the lumen of the oral cavity or the basal lamina. Rarely, some cells showed an evident bipolar shape. Small taste buds containing either alpha-gustducin-immunoreactive or alpha-gustducin-negative cells appeared in the vallate papillae of 4-day-old rats in which isolated, bipolar-shaped alpha-gustducin-immunoreactive cells were also found. After the first week of post-natal life, the taste buds appeared basically similar to those of adult animals. In conclusion, the present study demonstrates that the presence of epithelial cells with characteristics of solitary chemosensory cells precedes the development of the taste buds.     

Gene expression in rat dermal papilla cells: analysis of 2529 ESTs

Dermal papilla (DEPA) cells are resident at the base of hair follicles and are fundamental to hair growth and development. Cultured DEPA cells, in contrast to normal fibroblast cells, are capable of inducing de novo hair follicle growth in vivo. By differential screening of a DEPA cDNA library, we have demonstrated that dermal papilla cells are different from fibroblasts at the molecular level. We further studied these cells by random sequencing of 5130 clones from the DEPA cDNA library. Fifty percent had a BLASTX E value < or =1 x 10(-25). Twenty-one percent had similarity to proteins involved in cell structure/motility with 4 of the top 10 most abundant clones encoding extracellular matrix proteins. Clones encoding growth factor molecules were also abundant. The remaining 50.7% of clones had low similarity scores, demonstrating many novel molecules. For example, we identified a new CTGF family member, the rat homologue of Elm1.     

Observations on the ultrastructure of ganglion cells in the circumvallate papilla of rat and mouse

Ganglion cells in the circumvallate papilla of adult rodents are described as typical autonomic neurons. Some neurons are aggregated to form a discrete structure in the base of the papilla; others are scattered through the core, along the nerve bundles, and particularly near the dome. The term "circumvallate ganglion" is applied to the entire population. Satellite cells completely ensheathe each neuron. Preganglionic fibers, containing clear vesicles, synapse on the soma and stumpy dendrites of the neurons. Axons, containing dense-cored vesicles, are observed in close proximity to the neurons. However, these fibers do not establish true morphological synaptic contacts with the neurons. We have not observed serial or reciprocal synapses on or in the vicinity of the ganglion cells. The hypothesis that the axons of the circumvallate ganglion neurons act as parasympathetic vasodilators is indicated by the proximity of the two structures and by nerve terminations on the arteriole muscle cells. Direct modulation of taste transduction by these neurons is ruled out.