scholarly journals Cytochemical localization of alkaline phosphatase and Na+-pump sites in adult rat colon.

1979 ◽  
Vol 27 (9) ◽  
pp. 1231-1235 ◽  
Author(s):  
P B Vengesa ◽  
U Hopfer
Keyword(s):  
Alkaline Phosphatase ◽  
Enzyme Activity ◽  
Electron Microscope ◽  
Colonic Mucosa ◽  
Brush Border Membrane ◽  
Rat Colon ◽  
Adult Rats ◽  
Cytochemical Localization ◽  
Chief Cells ◽  
Adult Rat

The cellular and subcellular locialization of alkaline and K+-dependent phosphatase activities in the colonic mucosa of adult rats and rabbits was studied with the electron microscope. The 1-cysteine-sensitive alkaline phosphatase activity was observed in the brush border membrane of the chief cells. The contraluminal plasma membrane of chief cells was devoid of this enzyme activity. In contrast, the cardiac glycoside-sensitive K+-dependent phosphatase was predominantly localized in this region of the cheif cells.

ELECTRON MICROSCOPY OF ALKALINE PHOSPHATASE OF ESCHERICHIA COLI

1966 ◽  
Vol 12 (4) ◽  
pp. 605-607 ◽  
Author(s):  
V. M. Kushnarev ◽  
T. A. Smirnova
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Alkaline Phosphatase ◽  
Cell Wall ◽  
Enzyme Activity ◽  
Electron Microscope ◽  
Inorganic Phosphate ◽  
E Coli

A method is described for determining the localization of alkaline phosphatase in the cells of E. coli B with the electron microscope. Enzyme activity, determined by deposition of inorganic phosphate, is located in the exterior layer of the cell wall.

Ontogenic regulation of folate transport across rat jejunal brush-border membrane

2003 ◽  
Vol 285 (5) ◽  
pp. G1068-G1073 ◽  
Author(s):  
Krishnaswamy Balamurugan ◽  
Hamid M. Said
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Maximum Velocity ◽  
Initial Step ◽  
Mrna Levels ◽  
Folate Transport ◽  
Adult Rats ◽  
Physiological Concentration ◽  
Adult Rat ◽  
Weanling Rats

Folate is an essential micronutrient that in mammals must be obtained from exogenous sources via intestinal absorption. Previous studies from our laboratory and others have demonstrated that folate absorption from the small intestine is mediated via the reduced-folate carrier (RFC). The goal of this study was to determine whether the initial step of folate uptake by intestinal epithelial cells, i.e., transport across the brush-border membrane (BBM) of the polarized enterocytes, is ontogenically regulated, and if so, to determine the molecular mechanism involved. Purified BBM vesicles (BBMV) isolated from suckling, weanling, and adult rats were used in this study. The initial rate of carrier-mediated uptake of a physiological concentration of folic acid (0.1 μM) by jejunal BBMV was found to be significantly ( P < 0.01) higher in suckling compared with weanling rats, which was, in turn, significantly ( P < 0.01) higher than that in adult rats. This decline in carrier-mediated folate uptake with maturation was found to be mediated via a decrease in the maximum velocity of the folate uptake process (6.55 ± 0.87, 2.16 ± 0.10, 0.90 ± 0.16 pmol·mg protein-1·10 s-1 for suckling, weanling, and adult rats, respectively), with no changes in its apparent Km. Western blot analysis of BBM protein and real-time PCR showed RFC protein and mRNA levels, respectively, to be significantly ( P < 0.01 for both) higher in suckling compared with weanling rats, which were in turn significantly ( P < 0.01 for both) higher than that in adult rats. These changes were found by nuclear run-on assay to be associated with a parallel decline in the RFC transcriptional rate in jejunal epithelia with maturation. In situ hybridization showed a similar pattern of RFC message distribution along crypt/villus axis in suckling and adult rat jejunum. These results demonstrate for the first time that folate transport across the intestinal BBM is under ontogenic regulation during early stages of life and that this regulation involves a transcriptional regulatory mechanism(s).

Differential responses of femoral and vertebral bones to long-term excessive l-thyroxine administration in adult rats

1996 ◽  
Vol 134 (5) ◽  
pp. 655-659 ◽  
Author(s):  
Sompongse Suwanwalaikorn ◽  
Boonsong Ongphiphadhanakul ◽  
Lewis E Braverman ◽  
Daniel T Baran
Keyword(s):  
Gene Expression ◽  
Bone Mineral Density ◽  
Alkaline Phosphatase ◽  
Bone Mineral ◽  
Tartrate Resistant Acid Phosphatase ◽  
Mineral Density ◽  
Adult Rats ◽  
Vertebral Bone ◽  
Adult Rat

Suwanwalaikorn S, Ongphiphadhanakul B, Braverman LE, Baran DT. Differential responses of femoral and vertebral bones to long-term excessive l-thyroxine administration in adult rats. Eur J Endocrinol 1996;134:655–9. ISSN 0804–4643 Recent studies suggest that thyroid-stimulating hormone suppressive doses of thyroid hormone decrease bone mass in humans and growing rats. To determine the long-term effects of excessive l-thyroxine administration on the femur and vertebrae in an adult rat model, 20 male Sprague-Dawley rats (20 weeks old) were randomized into two groups. Group 1 received l-thyroxine (20 μg/100 g body weight ip daily), and group 2 received normal saline ip daily for 20 weeks. Femoral and lumbar vertebral bone mineral density measurements were performed at 0, 6, 15, 18 and 20 weeks of treatment. After 20 weeks of treatment, total RNA was isolated from both femoral and lumbar bones. Northern hybridization was performed with 32P-labeled DNA probes for osteocalcin, osteopontin, alkaline phosphatase and tartrate-resistant acid phosphatase. Significant decreases in bone mineral density in the femur of l-thyroxine-treated rats were observed after 15 weeks (p < 0.03). Lumbar bone mineral density was not affected. Both osteoblast (osteocalcin, osteopontin, alkaline phosphatase) and osteoclast (tartrate-resistant acid phosphatase) gene expression markers were increased significantly in the femoral bone (p < 0.001), but not in the lumbar vertebrae of the l-thyroxine-treated rats. We conclude that long-term administration of excessive doses of l-thyroxine to the adult rat preferentially affects femoral but not vertebral bone. This is manifested by decreased bone mineral density as well as increased gene expression markers for osteoblast and osteoclast activity in the femur. Daniel T Baran, Department of Orthopedics, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA

scholarly journals Inhibition studies of alkaline phosphatase in hard tissue-forming cells.

1975 ◽  
Vol 23 (5) ◽  
pp. 342-347 ◽  
Author(s):  
A Linde ◽  
B C Magnusson
Keyword(s):  
Alkaline Phosphatase ◽  
Enzyme Activity ◽  
Adenosine Triphosphatase ◽  
Ruthenium Red ◽  
Inorganic Pyrophosphatase ◽  
Alkaline Ph ◽  
Hard Tissue ◽  
Assay Condition ◽  
Phosphatase Inhibitors ◽  
Inhibition Studies

The effects of the alkaline phosphatase inhibitors levamisole and R 8231 on p-nitro-phenylphosphatase, inorganic pyrophosphatase and adenosine triphosphatase (ATPase) activities in dentingenically active odontoblasts were studied. The p-nitrophenylphosphatase and inorganic pyrophosphatase activities were inhibited, while 40% of the ATP-splitting enzyme activity remained under the assay condition used. This finding, togeather with earlier studies, indicates that at least two different phosphatase are active at alkaline pH in hard tissue-forming cells; on nonspecific alkaline phosphatase and one specific ATPase. The ATPase activity is uninfluenced by ouabain and ruthenium red and is activated by Ca-2+ ions.

Glycosyltransferases in plant and animal tissues effects of fixation and lead on enzyme activity.

1978 ◽  
Vol 26 (10) ◽  
pp. 772-781 ◽  
Author(s):  
W D Klohs ◽  
C W Goff ◽  
R J Bernacki
Keyword(s):  
Enzyme Activity ◽  
Lead Nitrate ◽  
Initial Step ◽  
Lead Ions ◽  
Fixation Time ◽  
Animal Tissues ◽  
Root Tips ◽  
Cytochemical Localization ◽  
Onion Root ◽  
L1210 Cells

As the initial step toward the cytochemical localization of glycosyl-transferases in situ, biochemical determinations of these enzyme activities from onion root tips and L1210 cells were performed before and after fixation as well as in the presence of lead ions. Glycosyltransferase activity from roots fixed in buffered formaldehyde or glutaraldehyde before homogenization decreased as the concentration of the fixative or fixation time was increased. Formaldehyde fixation was less inhibitory than glutaraldehyde; 35% of the glycosyltransferase activity was retained after 30 min fixation in 2% formaldehyde while 25% of the enzyme activity remained after a similar fixation in glutaraldehyde. Substantially higher levels of L1210 cell glycosyltransferase activity were retained after a 30 min 2% formaldehyde fixation (60% sialyltransferase; 82% galactosyltransferase), but inhibition by glutaraldehyde was similar to that observed for onion root galactosyltransferase. Glycosyltransferase from formaldehyde-fixed roots was inhbited 35% by lead nitrate, but sialytransferase from formaldehyde-fixed L1210 cells was unaffected by lead ions. These findings are encouraging for further studies aimed at the development of cytochemical technique to localize glycosyltransferase in plant and animal tissues.

scholarly journals Increase in alkaline phosphatase activity in calvaria cells cultured with diphosphonates

1979 ◽  
Vol 183 (1) ◽  
pp. 73-81 ◽  
Author(s):  
R Felix ◽  
H Fleisch
Keyword(s):  
Alkaline Phosphatase ◽  
Protein Synthesis ◽  
Enzyme Activity ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Heat Inactivation ◽  
High Concentration ◽  
Control Value ◽  
Km Value ◽  
Inhibitor Of Protein Synthesis

1. Dichloromethanediphosphonate and to a lesser degree 1-hydroxyethane-1,1-diphosphonate, two compounds characterized by a P-C-P bond, increased the alkaline phosphatase activity of cultured rat calvaria cells up to 30 times in a dose-dependent fashion. 2. Both diphosphonates also slightly inhibited the protein synthesis in these cells. 3. Thymidine, an inhibitor of cell division, did not inhibit the induction of the enzyme, indicating that the increase in enzyme activity was not due to the formation of a specific population of cells with high alkaline phosphatase activity. 4. The effect on alkaline phosphatase was suppressed by the addition of cycloheximide, an inhibitor of protein synthesis. 5. After subculturing the stimulated cells in medium without diphosphonates, the enzyme activity fell almost to the control value. 6. Bovine parathyrin diminished the enzyme activity of the control cells and the cells treated with dichloromethanediphosphonate; however, at high concentration the effect of parathyrin was greater on the diphosphonate-treated cells than on the control cells. 7. The electrophoretic behaviour, heat inactivation, inhibition by bromotetramisole or by phenylalanine, and the Km value of the induced enzyme were identical with that of the control enzyme.

scholarly journals Psyllium and fat in diets differentially affect the activities and expressions of colonic sphingomyelinases and caspase in mice

2004 ◽  
Vol 91 (5) ◽  
pp. 715-723 ◽  
Author(s):  
Yajun Cheng ◽  
Lena Ohlsson ◽  
Rui-Dong Duan
Keyword(s):  
Ulcerative Colitis ◽  
Alkaline Phosphatase ◽  
High Fat Diet ◽  
Colonic Mucosa ◽  
Caspase 3 ◽  
High Fat ◽  
Acid And Alkaline Phosphatase ◽  
Alkaline Sphingomyelinase ◽  
Opposite Manner ◽  
Colonic Tumours

Dietary fibre and fat affect colonic tumourigenesis and inflammation. Sphingomyelin metabolism may have implications for the pathogenesis of colonic tumours and ulcerative colitis. The present study examined the effects of psyllium and fat on the enzymes responsible for sphingomyelin metabolism and apoptosis in the colon. Mice were fed control, psyllium-containing (100 g/kg), high-fat (313 g/kg, 53 % energy as fat) or high-fat plus psyllium diets for 4 weeks. The activities of acid, neutral and alkaline sphingomyelinase (SMase), neutral ceramidase, and caspase 3, 8 and 9 in colonic mucosa were determined. The expressions of alkaline SMase and caspase 3 were examined. The psyllium-containing diet was found to increase significantly the activities of alkaline SMase and caspase 3 and decreased those of acid SMase and neutral ceramidase. The high-fat diet had opposite effects on these enzymes and attenuated the effects of psyllium. Western blotting showed that psyllium increased and high-fat decreased the levels of alkaline SMase and caspase 3 in colonic mucosa. The change in caspase 3 activity was positively correlated with that of alkaline SMase and negatively with acid SMase. No similar changes of acid and alkaline phosphatase activities in the colon or acid and neutral SMase activity in the liver were identified. In conclusion, colonic sphingomyelin metabolism and apoptosis were affected by psyllium and fat in an opposite manner. The results may have implications for colorectal tumourigenesis and inflammation.

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