Ultrastructural demonstration of alkaline phosphatase (ALP) and K+-p-nitrophenyl phosphatase (K+-p-NPPase) in the epidermal ionocytes of Blennius sanguinolentus

Cytochemical techniques were used for the light and electron microscopical localization of alkaline phosphatase and potassium-dependent nitrophenyl phosphatase in the epidermal ionocytes of the Teleost Blennius sanguinolentus. The heavier deposition of the reaction products obtained with the different media was shown in the cytoplasmic surface of the labyrinth tubules, the apical vesicles and in intimate association with plasmic membranes. Both plasma membranes and intracellular activities are affected by the addition of specific inhibitors L-p-bromotetramisole oxalate and ouabain) to both complete and control media. The significance of the cytoplasmic localization of both the two enzymes is discussed with reference to current models of transepithelial ion transportation.     

Ultrastructural demonstration of alkaline phosphatase (ALP) and K+-p-nitrophenyl phosphatase (K+-p-NPPase) in the epidermal ionocytes of Blennius sanguinolentus

Summary Cytochemical techniques were used for the light and electron microscopical localization of alkaline phosphatase and potassium-dependent nitrophenyl phosphatase in the epidermal ionocytes of the Teleost Blennius sanguinolentus.The heavier deposition of the reaction products obtained with the different media was shown in the cytoplasmic surface of the labyrinth tubules, the apical vesicles and in intimate association with plasmic membranes. Both plasma membranes and intracellular activities are affected by the addition of specific inhibitors l-p-bromotetramisole oxalate and ouabain) to both complete and control media.The significance of the cytoplasmic localization of both the two enzymes is discussed with reference to current models of transepithelial ion transportation.     

Alkaline phosphatase in mitochondria

In electron microscope cytochemical studies alkaline phosphatase activity was present in the mitochondria of all liver cells and associated with the plasma membrane of the cells of bile canaliculi. The mitochondrial activity was partially inhibited by L-phenylalanine and Levamisole but the plasma membrane associated activity was completely inhibited by Levamisole. Biochemical assays have shown that a significant amount of the total mouse liver alkaline phosphatase activity was present in the mitochondrial fraction. Starch gel electrophoresis showed that this mitochondrial alkaline phosphatase had a characteristic isoenzyme pattern, consisting of 3 distinct bands which were not retarded by neuraminidase treatment. The enzyme in the mitochondria-free supernatant showed one wide band which was retarded by neuraminidase.     

Activity and stability of alkaline phosphatase (ALP) immobilized onto magnetic nanoparticles (Fe3O4)

Direct binding of alkaline phosphatase (ALP) on magnetic nanoparticles (Fe(3)O(4)) in the presence of carbodiimide (CDI) using two different methods is described. The activity and stability of immobilized ALP with both shaking and sonication method were compared. The results indicated the ALP binding efficiency to be in the range of 80-100% with both the immobilization techniques. The activities retained were in the range of 20-38% with shaking method and 30-43% with sonication method, respectively. The activities of the immobilized ALP preparations were found to be stable compared to the free (unbound) ALP for at least 16-week storage period. Moreover, ALP immobilized on magnetic nanoparticles was successfully used for dephosphorylation of plasmid DNA before it was used for ligation reaction. The use of immobilized ALP for plasmid dephosphorylation allows easy manipulation, reduces the procedural time, and also avoids exposure of reaction mixture to high temperature.     

Loss of myocardial capillary endothelial-cell alkaline phosphatase (ALP) activity in primary endothelial cell culture

Primary cultures of rat myocardial capillary endothelial cells were established and characterized. A range of typical endothelial cell-specific markers were retained in vitro. Cell kinetic studies in confluent endothelial-cell cultures in vitro revealed a roughly 50-fold increase in the proportion of cells in s-phase, indicating a very considerable shortening of cell turnover time, compared to in vivo conditions. Alkaline phosphatase enzyme activity and encoding mRNA are strongly expressed in myocardial capillary endothelial cells in vivo, but were not detectable in vitro. This was true in cell cultures from two strains of rat, which revealed significantly different enzyme expression levels in vivo. In co-cultures of pericytes and endothelial cells, positive ALP enzyme reaction was detected in pericytes, which in vivo show only very weak enzyme reactivity. Treatment of cell cultures with ≤10 M retinoic acid had no effect in pure endothelial cell cultures, but did increase ALP expression of pericytes in co-cultures. The observation of a loss of endothelial ALP expression in vitro supports other in vitro as well as our own in vivo observations, indicating a negative correlation of ALP expression and proliferative activity of endothelial cells.     

Histochemical Investigations of Tardigrada. IV. Alkaline Phosphatase (ALP), Aminopeptidase (AMP) and Gonad Development in Eutardigrades

In tardigrades of the genus Macrobiotus histochemically localized alkaline phosphatase (ALP) and aminopeptidase (AMP) are taken as markers of absorptive/secretory cells. The enzyme reaction intensity is also related to different metabolic activities of the body tissues and compared with other histochemical and histological features of the cells. ALP and AMP distribution pattern is investigated in the Malpighian tubules, the gut, ovary, testicle and the storage and epidermal cells during female and male gonad development. The results strongly support the hypothesis that the Malpighian tubules are osmoregulatory-excretory organs and may also perform secretory functions. They show morpho-functional variations which are related to sexual maturity and differ in the female and the male: possible physiological roles are discussed. In the female all the tissues here examined undergo changes in size, enzyme activities and other features that show a relationship with phases of both oogenesis and molt: a physiological explanation is suggested that takes into account previously obtained evidence of neuroendocrine regulation. In the male the stages of testicle maturity and molt seem to be independent of each other and the changes of the body tissues found in the female are less or not evident.     

Alkaline phosphatase activity in the human tonsils and its relation to tonsillar diseases.

Alkaline phosphatase activity was examined in the human tonsils in fetal life and after repeated attacks of acute tonsillitis and in quinsy. Gomori's metal precipitate technique was used to demonstrate the phosphatase activity using four different substrates: sodium beta-glycerophosphate and adenosine triphosphate at pH 9, riboflavin 5-phosphate at pH 9.2 and 5-monophosphoric acid at pH 8.3. (2) The phosphatase activity differs somewhat according to the phosphate ester used as a substrate illustrating an example of 'substrate specificity'. (3) Alkaline phosphatase activity was increased in the case of both acute and chronic inflammation. This increase has been discussed in relation to such phenomena as transformation of lymphocytes into macrophages and antibody formation.     

Alkaline phosphatase and peroxidase in neutrophils of the catfish Ictalurus melas (Rafinesque) (Siluriformes Ictaluridae)

Summary Alkaline phosphatase and peroxidase activities were investigated in typical neutrophils and in vacuolated cells, the latter considered to be another type of neutrophil in catfish blood. This study was carried out by light- and electron-microscopy. Two lines of neutrophils were recognized in the peripheral blood of catfish. Alkaline phosphatase activity was present only in the vacuolated neutrophils; peroxidase activity appeared only in the typical neutrophils. The presence of two types of neutrophil in catfish blood suggests that important steps of neutrophil evolution occurred in fish.     

Tissue polypeptide antigen (TPA) in chronic active hepatitis and mild liver diseases.

Tissue polypeptide antigen (TPA) is a non-specific tumor marker with a broad reactivity. Increases in TPA are also observed in benign liver diseases. We conducted this study to evaluate the usefulness of TPA serum level determination in 15 patients with chronic active hepatitis (CAH) and in 30 patients with mild liver diseases (MLD) diagnosed at the time of evaluation. TPA levels were abnormal in 73.3% of CAH patients and in 40% of MLD patients. CAH patients had significantly higher TPA levels than MLD patients (p = 0.006). There was a significant correlation between TPA and ASAT (r = 0.581 p < 0.00001), suggesting that cytolysis plays an important role in the increase in TPA. A TPA value of twice the normal level will unlikely be due to MLD (specificity 90%). TPA can be used in the clinical characterization of these patients and in the selection of patients for biopsy.