The localization of alkaline phosphatase in tissues of mice, using the electron microscope

STUDIES ON THE ORGANIZATION OF THE BRUSH BORDER IN INTESTINAL EPITHELIAL CELLS : I. Tris Disruption of Isolated Hamster Brush Borders and Density Gradient Separation of Fractions

Brush borders isolated from the epithelial cells of hamster jejunum have been dissociated by treatment with 1 M Tris(hydroxymethyl)aminomethane into several subfractions which can be separated by means of centrifugation on glycerol density gradients. Investigation of the chemical specificity of disrupting agents suggests that the amino group of Tris, in its positively charged state, is involved. Five individual bands or fractions have been routinely recovered from density gradients. The distribution of alkaline phosphatase and maltase activities among these fractions has been studied and the results indicate that both enzymes are predominantly associated with one fraction which has been identified in a companion paper as being composed of the membranes of the brush border microvilli. A fibrillar material of unidentified origin has also been obtained from Tris-disrupted brush borders.

Ultrastructural and histochemical characterization of special muscle cells in the monkey small intestine

The ultrastructure, three-dimensional arrangement, and histochemical features of special muscle cells in the monkey small intestine were investigated. The cells formed a special layer separated from the main part by a connective tissue space along the submucosal surface of the circular muscle coat. Scanning electron microscopy using alkali maceration demonstrated this inner sublayer to be a continuous thin sheet consisting of irregularly-shaped muscle cells equipped with many cytoplasmic projections and caveolae. Other ultrastructural features included direct contact with interstitial cells, due to their close association with nerve fibers of the deep muscular plexus. Histochemical examination revealed significant alkaline phosphatase activity and immunoreactivity for vascular smooth muscle alpha actin in these muscle cells, whereas the ordinary circular muscle cells were immunopositive for enteric smooth muscle gamma actin. These findings suggest that the special muscle cells play an important role in regulating the radial stretch of the monkey small intestinal wall.

FINE STRUCTURE OF CELL SURFACE SPECIALIZATIONS IN THE MATURING DUODENAL MUCOSA OF THE CHICK

Cell surfaces in the duodenal mucosa have been studied in maturing tissue of the chick from incubation until hatching. Changes in the distribution of mitoses in this tissue give an indication of its rate of maturation. This rate is paralleled in developmental changes in microvilli and junctional complexes. Concentration of mitotic figures towards the base of villous folds is gradual from day 9 to day 16, then rapid to day 19, after which the mature pattern is acquired. By day 11, microvilli appear in a regular pattern which does not alter through hatching. Their height remains the same to day 16 when it increases gradually to day 19, then very sharply. The angle formed between the microvilli and the cell surface increases gradually to day 16, giving evidence of advancing internal structure. Changes in cell adhesion also occur at day 16. Thereafter, following trypsin treatment cells are held together in patches by the tight junctions of the terminal bar, although the desmosomes are separated. The timing of these morphological changes is compared with that of alkaline phosphatase accumulation in this tissue as reported by Moog (13). Increase in the surface area of the microvilli parallels the increase in the activity of the enzyme.

Effect of diazinon on freeze-fracture images of microvilli of intestinal epithelial cells of Tilapia nilotica

The effect of the organophosphate insecticide, diazinon on the intramembranous particles (IMPs) of the microvilli of the intestinal epithelial cells of Tilapia nilotica fish was studied using freeze-fracture technique. Exposing fish to different repeated concentrations of diazinon (1/2LC50) caused a significant decrease in population density of IMPs in P- and E-faces. IMPs of microvilli found in intestinal epithelial cells are thought to represent many kinds of proteins including enzymes. In the present work, it is suggested that diazinon induced a reduction in enzymatic content of the membrane which was accompanied by a decrease in IMPs density of the microvilli.

Fetotoxic alterations in the normal ontogenies of rat microsomal and lysosomal enzymes

The activity patterns during development for acid phosphatase (Ac-P), alkaline phosphatase (A1-P), beta-glucuronidase (beta G), and UDP-glucuronyltransferase (UDPGT) have been determined in various tissues of the rat for corn oil and distilled water controls as well as in animals prenatally exposed to four fetotoxic chemicals. Postnatal assays were performed on both sexes separately. In control animals, tissue-specific differences between male and female activity levels were found for UDPGT. In the liver of mature offspring, enzyme activity was greater in males than in females. Although no sex difference was observed in the intestine, the kidneys of females exhibited higher values than those of males. An original computer-assisted methodology is presented, designed (a) to permit a mathematical description for the complex curves exhibited by these ontogeny profiles, and (b) to assess the statistical significance of chemical-induced alterations in these complex developmental patterns, specifically, to target sensitive periods and subtle changes near the fetotoxic threshold. Oral administration (days 6-18 of gestation) of 3,3',4,4'-tetrachlorobiphenyl (4CB) to pregnant females resulted in an induction of liver UDPGT activity in offspring postnatally, and some alterations in the perinatal pattern of beta G in the same tissue. This treatment also produced differences in the intestinal patterns of Ac-P and male UDPGT. No significant changes were observed in offspring exposed to diethylstilbestrol (DES). Treatment with zeranol (ZN) caused reductions in activity over the entire postnatal period for beta G in liver, brain, intestine, and kidney, for A1-P in brain, and for Ac-P in the intestine. Cadmium-treated dams gave birth to offspring that exhibited slightly altered ontogenies only in intestine for UDPGT and AcP. The alterations in these developmental profiles indicate periods of increased sensitivity, and may be useful in directing more specific studies into the fetotoxic mechanisms of these compounds.

Distribution of activity of alkaline phosphatase and Mg-dependent adenosine triphosphatase in the cranial dura mater-arachnoid interface zone of the rat

The distribution of the activity of alkaline phosphatase and Mg-dependent adenosine triphosphatase was studied in the encephalic dura mater-arachnoid borderline (interface) zone of albino Wistar rats. Intense clustering of electron-dense granules that indicated alkaline phosphatase activity was observed in the inner dural cells, the neurothelial cells, the outermost row of the outer arachnoidal cells and in the intercellular cleft between the latter two (the so-called electron-dense band). The remainder of the outer arachnoidal cells contained almost no reaction product. Mg-adenosine triphosphatase activity was distributed differently; a lack of reaction product was observed not only in the outer arachnoidal cells, but also in the zone occupied by the electron-dense band. The data confirm histochemically the barrier properties of the dura mater-arachnoid interface zone.

Physiological responses of chicken gut tissue to coccidial infection: comparative effects of Eimeria acervulina and Eimeria mitis on mucosal mass, carotenoid content, and brush border enzyme activity

Broiler chicks, 3 to 4 wk of age, were inoculated with either Eimeria acervulina or E. mitis, and mucosal dry weights, brush border enzyme activities, and carotenoid contents as well as plasma carotenoid levels were measured at 3, 5, and 7 days postinoculation (PI). At 5 and 7 days PI mucosal dry weights, brush border enzyme activities, and carotenoid contents were significantly decreased at primary sites of infection (duodenum, E. acervulina; lower small intestine, E. mitis). In contrast, at sites remote from infection, mucosal dry weights and brush border enzyme activities were significantly increased above control values. However, mucosal carotenoid contents were significantly decreased. Between 5 and 7 days PI mucosal renewal as signalled by increases in dry weight was accompanied by increases in brush border enzyme activities. However, mucosal carotenoid contents were further decreased. High correlations were found between plasma carotenoid levels and total mucosal carotenoids in control and coccidia-infected chicks, but not in 48-h-starved chicks. Infection with coccidia increased this correlation, and the increase with E. acervulina infection was significant. These data indicate that hyperplastic and renewing mucosal tissue is defective in absorbing carotenoids, and further, that there is no direct relationship between mucosal carotenoid content and brush border enzyme activities. Apparently carotenoids are not mobilized from body depots during the first week of coccidial infections as they are during 48-h starvation.

Electron-microscopic cytochemistry of alkaline-phosphatase activity in endothelium, pericytes and oligodendrocytes in the rat brain

The fine structural localization of alkaline-phosphatase (ALP) activity was investigated in the endothelial cells and pericytes of blood vessels and in the oligodendrocytes of rat cerebral cortex and corpus callosum by means of electron-microscopic (EM) cytochemistry using the lead-citrate method. ALP activity was associated with both the luminal and abluminal plasma membranes of some endothelial cells, but in other endothelial cells, this activity was found inside the cytoplasm. In some pericytes, ALP activity was associated with the plasma membrane but in others, strong activity was exhibited within both the cytoplasm and nucleus. Light, medium and dark oligodendrocytes showed ALP activity on their plasma membranes; on the other hand, immature oligodendrocytes exhibited activity within the cytoplasm and on the part of their plasma membrane. Within the cytoplasm of these reacted immature cells, the rough endoplasmic reticulum, nuclear membrane and outer membrane of the mitochondria were the main sites of ALP reaction. Endothelial cells, pericytes and oligodendrocytes demonstrated ALP activity along their plasma membrane or within their cytoplasm, and pericytes showed it within their nuclei. In particular, oligodendrocytes retained ALP activity throughout their cell life, and the intracellular distribution of this activity altered as they matured.

Developmental changeover in rat duodenal alkaline phosphatase

The specific activity of alkaline phosphatase in the rat duodenum increased just prior to birth, leveled off and then increased again at about 20 days after birth. During the postnatal rise in activity the electrophoretic pattern of the enzyme on sodium dodecyl sulphate (SDS) polyacrylamide gels changed from a single activity band to three bands. The changed pattern was identical with that of the adult duodenal enzyme. The fetal- and adult-type enzymes had different sensitivities to neuraminidase, suggesting that there is a significant difference in the sialic acid content of these two forms. This molecular conversion may be necessary for adaptation to eating a solid food diet, because it occurs just before the weaning period.

The site of benzyl penicillin accumulation in Penicillium chrysogenum

Benzyl penicillin was localized in cells of Penicillium chrysogenum by means of enzymatical and immunological methods, enabling the determination of minute amounts of penicillin. The reactions were performed on ultrathin sections. They allow to determine the antibiotic inside of the cells. The results indicate that benzyl penicillin is present in the vesicles belonging to the Golgi apparatus. Benzyl penicillin is transported from the cytoplasm outside the cell membrane by the Golgi vesicles.

Effect of prenatal and neonatal pantothenic acid deficiency on rat intestinal phosphatases

Alkaline phosphatase activity was increased in the distal part of the small intestine of pantothenic acid deficient neonatal rats, while acid phosphatase activity was slightly increased and protein concentration was decreased throughout the small intestine. The growth and maturation of the distal part of the small intestine were retarded more severely than in the proximal part.

Histochemical (polysaccharides, proteins, nucleic acids and enzymes) and autoradiographic (incorporation of 35S labelled sodium sulfate) study of the epithelial intestinal cells of Xenodon merremii Wagler, 1824 (Ophidia)

A histochemical and autoradiographic study of the lining intestinal epithelium of the snake Xenodon merremii is reported. The absorptive cells present neutral polysaccharides, arginine, tyrosine, tryptophan, cysteine, alkaline phosphatase, acid phosphatase, ATPase, AMPase, esterase and RNA. There are histochemical differences between the goblet cells of the small and of the large intestine. Whereas in the former predominates the neutral polysaccharides and are found arginine, tyrosine, tryptophan and cysteine, in the latter predominates the sulfated polysaccharides (confirmed by the uptake of radioactive sulfur) and no amino acids were found.

Isolation and characterization of the brush border fraction from newborn rat renal proximal tubule cells

A renal brush border fraction was isolated from newborn Sprague-Dawley rats, and its morphological and enzymatic characteristics were studied in comparison to that from the adult. Definite microvillar structures are seen by electron microscopy, and border preparations from the newborn are enriched in known marker enzymes. Though morphological development is more advanced and enzyme specific activities are greater in the adult, polyacrylamide gel electrophoresis of membrane proteins reveals no significant change in pattern with increasing age. These studies suggest that the brush border of the proximal tubule cell is present at birth as a significantly developed structure.

Fine structural localization of alkaline phosphatase in the granular pneumonocytes of hamster lung

The fine structural localization of nonspecific alkaline phosphatase was studied in the granular pneumonocytes (type II alveolar epithelial cells) of hamster lung by incubating sections of glutaraldehyde-fixed tissues in a medium containing lead ions and sodium beta-glycerophosphate or alpha-naphthyl acid phosphate. The specificity of the reaction was tested by exposing the sections to inhibitors of alkaline phosphatase. The results showed that alkaline phosphatase activity was present in the inclusion bodies of granular pneumonocytes. The enzyme reaction was strong in the membrane lining the inclusion bodies and a weaker reaction was generally detectable in the inclusion contents. Although only a proportion of the inclusion bodies showed enzyme activity, there was no obvious correlation between the reactivity of the inclusions and their intracellular position or size. The other organelles were unreactive. The finding of alkaline phosphatase activity within the inclusion bodies of granular pneumonocytes is an enigma as these organelles are generally considered to be lyosomes.

Alkaline phosphatase from pig kidney. Method of purification and molecular properties

Alkaline phosphatase (EC 3.1.3.1) from pig kidney brush-border membranes was solubilized from membrane precipitates by butan-1-ol at a critical pH of 7.0. The 12000-fold purification procedure included (NH(4))(2)SO(4) precipitation, DEAE-and TEAE-cellulose chromatography, Sephadex G-200 gel filtration and neuraminidase digestion followed by DEAE-cellulose chromatography. The purified protein contained 20% (w/w) carbohydrate and had mol.wt. 150000-156000 as estimated by Sephadex filtration and ultracentrifuge analysis. It was a tetrameric glycoprotein consisting of identical subunits, and it had a molecular activity at 25 degrees C of 2600s(-1) per tetramer. Its concentration in kidney was estimated to be 8.5-8.8mg/kg.

Localization of the action of cholera toxin on adenyl cyclase in mucosal epithelial cells of rabbit intestine

Brush borders and plasma membranes have been purified from mucosal epithelial cells of rabbit ileum under control conditions and after treatment for 3 hr with cholera toxin in vivo. The activity of several enzymes in these preparations was measured. It was concluded that adenyl cyclase, like NaK-ATPase, seems not to be a normal constituent of brush borders. Both these enzymes are present in plasma membrane preparations derived largely from the basal and lateral margins of the epithelial cells, both may be phospholipid dependent enzymes and both are affected by cholera toxin. Adenyl cyclase activity is increased while NaK-ATPase is decreased. The activities of alkaline phosphatase, leucineaminopeptidase, 5'-nucleotidase, glucose-6-phosphatase, and Mg-ATPase were not found to be affected by the toxin. Cholera toxin, which makes contact with the luminal side of the epithelial cells, in the natural disease and in the experimental model, would appear to exert its pathologic effect on adenyl cyclase at the opposite (basal and lateral) side of the cells.

Preparation and characterization of the lateral and basal plasma membranes of the rat intestinal epithelial cell

A technique is described for the isolation of a plasma-membrane fraction from the rat intestinal epithelial cell which is distinct from the microvillus membrane of that cell. The isolated fraction contains only about 0.2% of the sucrase activity in the original homogenate and negligible quantities of nuclear and mitochondrial membrane markers. It contains 12% of the total Na(+),K(+)-dependent adenosine triphosphatase and 7% of the alkaline phosphatase, with significant increments in specific activity of these enzymes. Multiple membrane preparations were highly reproducible with respect to the specific activities of the markers studied. The small intestine of one rat yields material containing about 1.3mg of protein. In addition an assay is described suitable for determining 5'-nucleotidase in the small intestine.