Effect of chloramphenicol on the activity of alkaline phosphatase (EC 3.1.3.1.) and the structure of microvilli of the epithelial cells of the small intestine of the hen

Effect of a therapeutic dose of chloramphenicol (detreomycin) on the intensity of reaction of alkaline phosphatase and on the structure of microvilli of the epithelial cells of the small intestine of the hen was investigated. It was observed that this antibiotic given orally weakened the intensity of the reaction of alkaline phosphatase and changes also the shape of microvilli of intestinal epithelium. 4 weeks after chloramphenicol administration the activity of the enzyme appeared to be normal and the morphology restored. We concluded from the experiments performed, that chloraphenicol may inhibit the process of protein glycosylation in the enterocytes of the small intestine and also weakened reversible the process of absorption.     

Effect of weaning terms and protein deficit in the rat pup nutrition on activities of digestive enzymes

Restriction of protein in nutrition of rat pups weaned at different terms has been found to produce changes in activities of digestive enzymes (maltase, alkaline phosphatase, aminopeptidase M, and glycyl-L-leucine dipeptidase) in the small and large intestine both at once after cessation of nutrition with low-protein diet for 10 days and 4 months later. In adult animals after the earlier or later weaning there are observed not only a decrease or increase of the enzyme activities, but also a different type of distribution of the alkaline phosphatase activity along the small intestine, which is more pronounced in the lately weaned rats. Thus, disturbance of metabolic programming of enzyme systems of the small and large intestine due to a change of quality of nutrition in early ontogenesis depends on terms of weaning of animals.     

Short-term effects of spermine ingestion on the small intestine: a comparison of suckling and weaned rats

We have previously shown that spermine, shortly after its ingestion, can induce the alteration of the morphology of the small intestine of suckling rats. It was proposed that this alteration is due to polyamine accumulation inside the epithelial cells. This could also be related to the fact that the intestine of the suckling rat is in an immature state. To shed light on this issue, disaccharidase and alkaline phosphatase activity assays, protein, DNA and RNA content measurements and polyamine concentration analysis were performed on the small intestine of suckling and weaned Wistar rats treated with spermine. Spermine did not induce the same intestinal alterations in weaned rats compared to suckling animals. Indeed, in sucklings, spermine administration induced a decrease of the protein, DNA, putrescine and spermidine intestinal content, suggesting a cell loss. The cell loss impaired the activity of intestinal enzymes: lactase, maltase and alkaline phosphatase. In weaned rats, the same treatment did not alter these parameters. Exogenous spermine by itself is not sufficient to induce the alterations described here and previously. The maturity degree of the small intestine could be the basis of this process.     

Effect of weaning terms and protein deficit in rat pup nutrition on activities of digestive enzymes

Restriction of protein in nutrition of rat pups weaned at different terms has been found to produce changes in activities of digestive enzymes (maltase, alkaline phosphatase, aminopeptidase M, and glycyl-L-leucine dipeptidase) in the small and large intestine both at once after cessation of nutrition with low-protein diet for 10 days and 4 months later. In adult animals after the earlier or later weaning there are observed not only a decrease or increase of the enzyme activities, but also a different type of distribution of the alkaline phosphatase activity along the small intestine, which is more pronounced in the lately weaned rats. Thus, disturbance of metabolic programming of enzyme systems of the small and large intestine due to a change of quality of nutrition in early ontogenesis depends on terms of weaning of animals.     

Morphological effects of high dose neomycin sulphate on the small and large intestine

The morphology of the intestinal wall and the activity of certain mucosal enzyme systems in the course of neomycin treatment were evaluated. Conventional and, to study the role of the bacterial flora, germ-free rats received 500 mg neomycin daily by stomach tube. Rats were sacrificed after seven days and small intestine (proximal and distal part) together with segments of the colon were removed and prepared for histochemistry. The colon and proximal small intestine of untreated conventional and germ-free animals did not show appreciable differences in staining activity after treatment with neomycin. Neomycin diminished both in normal and germ-free rats the activity of NAD tetrazolium reductase, succinate dehydrogenase, esterase, alkaline phosphatase and acid phosphatase in the distal small intestine. The findings of this study indicate that explanations for the beneficial effects of neomycin on hyperammonemia in liver disease should not only include the bactericidal action of neomycin but also its influence on absorption and metabolic functions of the mucosal cells.     

Subcellular localization of enterokinase (Enteropeptidase EC 3.4.21.9) in rat small intestine

The subcellular localization of enterokinase is controversial. In this study, enterokinase was extracted from a soluble fraction and a brush border fraction of rat small intestine by differential centrifugation. The soluble fraction contained 41% of the initial enterokinase activity while the brush border fraction contained only 4.6% of the initial activity. In contrast, alkaline phosphatase monitored as a brush border marker, yielded 26.3 in the brush border fraction and only 6% in the soluble fraction. Further separation of the soluble fraction on a Sepharose 4B column revealed three peaks of enterokinase activity. One small peak (3%) of a bound enzyme (M_r, 2·10^?6) and two larger peaks of free enzyme (M_r, 3·10⁵ and 9·10⁵). In contrast, alkaline phosphatase major fraction was in a high molecular weight peak of bound enzyme. When the brush border fraction was chromatographed only a single peak of bound enterokinase and alkaline phosphatase were found. In the lower part of the small intestine, no brush border-bound enterokinase was found, while the peak of alkaline phosphatase was the same as in the upper intestine. These data suggest that enterokinase activity in the rat intestine is mainly in a free form localized in the mucin and soluble fraction and to a negligible extent in the brush border.     

The influence of protein starvation on hydrolytic and transport characteristics of the rat small intestine in chronic experiments

Time dynamics of maltose, glycylglycine, glucose, and glycine hydrolysis and absorption in isolated loop of the small intestine was studied in chronic experiments on Wistar rats (group 1) after their transition from the standard diet to the protein-free one with enhanced content of carbohydrates. During protein starvation, there were different changes in the rates of glucose and glycine absorption, and glycylglycine hydrolysis and absorption in isolated intestinal loop, but to the end of the 2nd week they returned to the initial levels (for glucose and glycylglycine) or increased (for glycine). The rates of maltose hydrolysis and derived glucose absorption remained at the initial levels for the first days of protein starvation, decreased on the 5th day, and did not change afterwards. Maltase, alkaline phosphatase, and amino peptidase M activities, determined in homogenates of the small intestinal mucosa (per g of the tissue) after 2 weeks of protein starvation, were lower in the rats of group 1 in comparison with the rats of group 2, kept on the standard diet. Thus, under protein deficiency the hydrolytic and absorptive capacities of the small intestine correspond to both ingested food composition, and body requirements.     

Histophysiologic aspects of the remnant intestine of rats subjected to partial resection of the small intestine

The effect of small bowel resection on the morphology, mucous secretion and alkaline phosphatase activity of the remnant intestine was studied five months after surgical operation. Distal small bowel resection produced hyperplasia and infiltration of lymphocytes. The intestinal neutral and acid mucosubstances, and the alkaline phosphatase activity were increased in resected animals, whilst the sulphomucins content of goblet cells was unaltered. The serum alkaline phosphatase activity two and five months after resection was also increased.     

Effect of fasting on Na-K-ATPase activity in rat small intestinal mucosa

The effect of fasting on mucosal Na-K-ATPase activity in various regions of rat small intestine was investigated. Fasting (17--48 h) was associated with a consistent decrease in specific and total activity of Na-K-ATPase in the jejunum, the levels tending to rise more distally. No effect on the specific activities of Mg-ATPase or alkaline phosphatase was found. Fasting was also associated with incresed adrenocortical activity and with decreases in mucosal mass, protein content, and histological dimensions of the jejunum, no similar changes being found in the distal small intestine. Glucose ingestion prevented the decrease in jejunal enzyme activity associated with fasting and elevated levels in the mid and terminal small intestine of fed animals. These effects suggest that Na-K-ATPase activity in small intestinal mucosa may be, in part, inducible.     

Effect of fluorine on enzyme activity in the small intestine mucosa during absorption of sodium, potassium, monosaccharides and amino acids

Effect of NaF on ATP-ase, creatine kinase, acid and basic phosphatases activity of small intestine mucosa in white rats during enteral administration of NaCl, KCl solutions has been studied under conditions of acute experiment. Inhibition of the Mg2+-ATP-ase activity by 13%, general ATP-ase activity by 25%, creatine kinase by 22% and a 2.2-3 fold inhibition of Na, K+-ATP-ase activity is observed. Acid and basic phosphatase activity does not change, swelling of mucosa is observed. The acid phosphatase activity in the intestinal contents increases 1.5 times, basic phosphatase activity--1.7 times, creatine amount--1.7 times, Pi amount 1.8 times. In experiments in vitro F- produces 20% activation of the basic phosphatase of mucosa and a 2.6-fold inhibition of the acid phosphatase. Rate of fructose absorption falls by 34%, that of methionine--by 29%, glucose--by 24%, glutaminic acid--by 10%. Activity of general ATP-ase in this case decreases by 22, 15, 27, 20% respectively. It is supposed that the F- effect results in destabilization of the membrane structures of the intestine mucosa.     

Influence of Mg2+ ions on the activity measurement of isoenzymes of alkaline phosphatase

The activity of alkaline phosphatase isoenzymes from liver, bone and small intestine is differently influenced by Mg2+. The stimulation of isoenzymes from liver and bone is higher by Mg2+ ions than in the case of isoenzymes from small intestine. An obligatory preincubation of the serum sample in a buffer-Mg2+ mixture is necessary to avoid difficulties which may arise in the kinetic determination of alkaline phosphatase activity under extreme conditions, i.e. low Mg2+ concentration in serum, the necessity of dilution of the sample or the high isoenzyme content from liver or bone in the serum.     

Diet and histophysiology of the alimentary canal of Lumbricillus lineatus (Oligochaeta,Enchytraeidae)

Lumbricillus lineatus selectively ingests masses of organic and inorganic interstitial particles from a sand-clay substratum in the upper littoral zone. Particle-masses are ingested, passed along the esophagus and into the anterior intestine where the pH becomes acid. A- and C-esterases, acid -galactosidase, acid phosphatase and -N-acetylglucosaminidase are present in the epithelium, while the rotating food masses are surrounded by a membrane of sulphated, acid glycoprotein. These enzymes, with the exception of acid phosphatase and the addition of aminopeptidase M, are also present in the epithelia of the mid and posterior intestinal regions where the pH is alkaline. The cells in the ventral wall of the mid intestinal region contain high concentrations of alkaline phosphatase, acid -galactosidase and -N-acetylglucosaminidase. The food consists of absorbed organics and bacteria with absorption and intracellular digestion occurring along the intestine, particularly in the mid ventral region.     

Effect of aflatoxin B1 on CD3 T cells andalkaline phosphatase in the intestine of mice

The aim of the study was to determine the effect of repeated applications of aflatoxin B₁ (AFB₁) on immunocompetent cells (CD3 T cells) and alkaline phosphatase in the intestinal mucosa. Mice were orally treated with AFB₁ for 24 days. The mucosa of the intestine showed a significant decrease in the number of CD3 T cells and a significantly lower level activity of alkaline phosphatase on day 24 in AFB₁ treated mice. Similarly, with changes in the small intestine, qualitative haematological parameters were modified in systemic immunity as lymphopenia, and neutropenia, monocytopenia. AFB₁ treated animals showed reduction in body weight gain and increased liver weight. We supposed that changes found in the small intestine are secondary to primary systemic haematological lesions. The decrease in CD3 T cells suggests a connection with the decrease in the host's resistance to infectious diseases. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effect of phloretin and phloridzin on properties of digestion and absorption in the rat small intestine

Experiments in vitro on everted sacs of rat small intestine have shown that phloretin (an inhibitor of basolatheral glucose GLUT2 transporter) added from mucosal side of the sacs decreases release of glucose from enterocytes into serosal fluid without changing glucose accumulation in tissue of the preparations. Addition of phloridzin (an inhibitor of Na⁺ and glucose co-transporter SGLT1) from mucosal side inhibited both glucose accumulation in the tissue and its release into serosal fluid. Unspecific effects of phloretin and phloridzin on activities of several digestive enzymes (in particular, alkaline phosphatase, amino peptidase, and glycyl-L-leucine dipeptidase) has been revealed in homogenates of the rat small intestine mucosa. In chronic experiments on rats, absorption of glycine from the isolated small intestinal loop was inhibited in the presence of phloretin in perfusate. The obtained results indicate that the experimental approach of inhibition of glucose absorption by phloretin used from mucosal side in vitro appears to give a significant overestimation of contribution of facilitated diffusion (with participation of the GLUT2 transporter inserted in the apical enterocyte membrane) to glucose transport across this membrane. Thus, the role of the GLUT2 transporter in the mechanism of glucose absorption in the small intestine under its physiological conditions does not seem to be as great as it is thought by the authors of the recently proposed hypothesis.     

Effect of pentagastrin, secretin and cholecystokinin on growth and differentiation in organ cultured rabbit small intestine

The effect of pentagastrin, secretin and cholecystokinin on biochemical parameters of mucosal growth and differentiation was studied in organ cultured rabbit jejunum and ileum. Pentagastrin at 0.05-5.0 microgram/ml did not affect DNA content of the biopsy, but led to a significant decrease of sucrase and alkaline phosphatase activity in the ileum. Secretin prompted a significant decrease of DNA and protein in the ileum at a level of 10(-7) and 10(-5) M, but had no effect in the jejunum. Of the brush border enzymes, sucrase and alkaline phosphatase were suppressed in both parts of the intestine both with respect to specific activity and total biopsy content. Cholecystokinin, like pentagastrin, did not influence DNA or protein content, but reduced sucrase, maltase and alkaline phosphatase activity. HMG-CoA reductase, the key enzyme of cholesterol synthesis, was not significantly affected by any of the three hormones tested. When brush border enzymes or DNA from desquamated cells were measured in the post-culture medium, no consistent effect of any gastrointestinal hormone was apparent. The present study demonstrates a direct "antitrophic" effect of secretin in cultured mucosa. Pentagastrin and cholecystokinin did not influence mucosal DNA content in vitro but apparently inhibited villus cell differentiation.     

Biochemical Localization of Alkaline Phosphatase in the Cell Wall of a Marine Pseudomonad

The various layers of the cell envelope of marine pseudomonad B-16 (ATCC 19855) have been separated from the cells and assayed directly for alkaline phosphatase activity under conditions established previously to be optimum for maintenance of the activity of the enzyme. Under conditions known to lead to the release of the contents of the periplasmic space from the cells, over 90% of the alkaline phosphatase was released into the medium. Neither the loosely bound outer layer nor the outer double-track layer (cell wall membrane) showed significant activity. A small amount of the alkaline phosphatase activity of the cells remained associated with the mureinoplasts when the outer layers of the cell wall were removed. Upon treatment of the mureinoplasts with lysozyme, some alkaline phosphatase was released into the medium and some remained with the protoplasts formed. Cells washed and suspended in 0.5 M NaCl were lysed by treatment with 2% toluene, and 95% of the alkaline phosphatase in the cells was released into the medium. Cells washed and suspended in complete salts solution (0.3 M NaCl, 0.05 M MgSO(4), and 0.01 M KCl) or 0.05 M MgSO(4) appeared intact after treatment with toluene but lost 50 and 10%, respectively, of their alkaline phosphatase. The results suggest that the presence of Mg(2+) in the cell wall is necessary to prevent disruption of the cells by toluene and may also be required to prevent the release of alkaline phosphatase by toluene when disruption of the cells by toluene does not take place.     

Age related effects of organochlorine insecticide lindane on intestinal brush border membrane in rats.

The effect of oral administration of lindane (gamma-HCH) has been studied on the intestine in 10-day, 20-day and 100-day old rats. In 10 day-old suckling pups exposed to lindane, there was a significant decrease in the activities of sucrase (29%), lactase (20%) and that of alkaline phosphatase (24%) compared to control. Sialic acid content of the brush borders was significantly decreased (29%) in 10-day old as well as in 20- and 100-day old rats (20 and 25% respectively), while fucose content of the membranes was significantly enhanced in all the age groups upon pesticide treatment. Among the brush border lipids, cholesterol content was significantly increased in all the age groups studied, the maximum increase of 35% being observed in 10-day-old rats. Membrane phospholipids were also increased in 20- and 100-day old animals (22% each) on lindane exposure. The present studies indicated that brush border membranes of suckling rat intestine were more susceptible to pesticide induced changes compared to older animals.     

Histochemical changes in the fowl small intestine associated with enhanced absorption after feed restriction

Summary The morphology and histochemical enzyme pattern of the small intestine were investigated in chicks undergoing feed restriction. Corresponding intestinal sites were compared in both restricted birds and in control birds under normal feeding. Intestines from the restricted birds showed some atrophy, the villi being slightly shorter and thinner than normal after eight days restriction, and there was an increase in the activity of alkaline phosphatase, leucine naphthylamidase, acid phosphatase, -glucuronidase, non-specific esterase and succinic dehydrogenase in the absorptive cells.The significance of these findings has been discussed in relation to the enhanced absorptive capacity of the intestine during feed restriction and its similarity to other dietary stress factors that produce enhanced absorption. Possible mechanisms for the production of such mucosal changes have been considered. It was concluded that the enhanced absorption of nutrients in semi-starved animals is correlated with increased mucosal enzyme activities.     

Translation of rat intestinal RNA yields two alkaline phosphatases.

After translation of total rat intestinal RNA, immunoprecipitation using monospecific antiserum against rat intestinal alkaline phosphatase yielded two polypeptides in the adult duodenum and jejunum (molecular masses 62 and 65 kDa). Immunoprecipitation of both bands was blocked by a single purified alkaline phosphatase. In the adult ileum and in the entire small intestine of suckling pups, only the 62 kDa translation product was found. After fat feeding, translated alkaline phosphatase increased by an amount proportionate to the increase in enzyme activity previously seen in the serum. A small fraction of nascent alkaline phosphatase was translocated into microsomal vesicles, producing peptides of 65 and 69 kDa. Tunicamycin-treated membranes demonstrated a different signal peptide for each translation product. N-Terminal sequencing of the translation products showed leucine residues at similar positions, but overlap with the mature protein sequence was not demonstrated. On the basis of these data, we propose the presence of two mRNAs encoding alkaline phosphatase in the rat intestine.