Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.26 (invertase)
4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To evaluate whether the small bowel can be distracted by mechanical stress in analogy to limb lengthening by osteodistraction, a gut-lengthening apparatus was designed. This distractor was placed at the antimesenterical side of a defined jejunum segment in rabbits. Distraction was performed by 1 mm lengthening of the distractor once daily using extracorporal screws. An effective gut lengthening was achieved of 9.9 +/- 0.5 mm (approximately 100%) within 3 weeks. Treated animals gained weight and remained in good general condition. Fasting plasma levels of cholecystokinin, neurotensin, glucagon-like peptide-1, gastric inhibitory polypeptide, and insulin remained unaffected. Postoperative factor XIII levels were significantly diminished and gastrin was elevated during gut distraction. DNA and protein concentrations in the mucosa of the distracted gut segments corresponded to controls. Mucosal lactase and saccharase activities were reduced. In the distracted bowel segments total tunica muscularis thickness was more than doubled due to muscle cell hypertrophy. In distracted segments villous width was increased. Detection of proliferating mucosal crypt cells utilizing BrdUrd labeling revealed no effects. In conclusion, small gut lengthening by mechanical distraction is possible without major changes in gut morphology. This technique may hint a novel experimental approach for the treatment of short bowel syndrome.
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PMID:Small bowel lengthening by mechanical distraction. 924 19

Non-physiological amounts of oral polyamines have been reported to induce precocious gut maturation in rat pups. The aim of the present study was to investigate organ distribution and metabolic fate of orally administered stable-isotopically labelled polyamines in rat pups. Pups received tetradeuterium-labelled putrescine (Pu-d4; 3 mumol), spermidine (Sd-d4; 5 mumol), spermine (Sp-d4; 3 mumol), or physiological saline twice daily on postnatal days 7-10 or 12-15. They were killed on days 10 and 15. We determined activities of ileal lactase (EC 3.2.1.23), maltase (EC 3.2.1.20), sucrase (EC 3.2.1.48) and diamine oxidase (EC 1.4.3.6) and established villus and crypt lengths. Polyamines and their labelling percentages in organs were determined by GC and mass fragmentography. Treatments did not affect growth rate, but caused lower weights of liver, kidneys and heart. Maltase activity increased, lactase decreased, whereas sucrase and diamine oxidase did not change. Villus and crypt lengths increased. Organ polyamine pools were labelled to different extents. Irrespective of the orally administered polyamine, all organs contained Pu-d4, SD-d4 and Sp-d4. Administered Pu-d4 and Sd-d4 were recovered mainly as Sd-d4, whereas Sp-d4 was recovered as Sp-d4 and Sd-d4. Total polyamines in a caecum, colon and erythrocytes increased, but increases were only to a minor extent with regard to labelled polyamines. Our data confirm precocious gut maturation by exogenous polyamines. Putrescine appears to be limiting factor. The exogenous polyamines were distributed among all investigated organs. They are not only used for the synthesis of higher polyamines, but also retroconverted to their precursors. Changes in erythrocyte polyamine contents suggest precocious stimulation of erythropoiesis.
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PMID:Oral administration of deuterium-labelled polyamines to sucking rat pups: luminal uptake, metabolic fate and effects on gastrointestinal maturation. 938 89

Differences in feeding rates and digestive efficiency of alternative experimental diets differing in cellulose or fiber and a secondary metabolite (the hydrolyzable tannin, tannic acid [TA]) were assessed with the herbivorous burrowing caviomorph rodent Octodon degus (degu). Degus live in open scrub subjected to summer droughts. The in vitro activity of the digestive enzyme sucrase was not significantly different between treatments with high and low TA. Analysis of the whole organism allowed us to conclude that in vitro analyses of enzymatic digestive activity and plant defenses cannot be used to explain and fully understand the physiological and behavioral effects of plant defenses on mammalian herbivores. We observed no body mass reduction due to effects of dietary treatments. O. degus seemed to compensate for nutritionally poor food by increasing gut content volume. We conclude that fiber and secondary compounds may influence feeding and digestive strategies and vice versa.
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PMID:Feeding and digesting fiber and tannins by an herbivorous rodent, Octodon degus (Rodentia:Caviomorpha). 940 39

The adaptive modulation hypothesis posits that the expression of digestive proteins should be modulated in response to intake of their respective substrates. A corollary of this hypothesis suggests that dietary flexibility and digestive plasticity should be correlated. We examined these two hypotheses in two granivorous Chilean birds (Zonotrichia capensis and Diuca diuca) that differ in dietary breadth. D. diuca is a strict granivore, whereas Z. capensis also eats insects. In field-caught birds, the activity of the intestinal dipeptidase aminopeptidase-N was positively correlated with intake of insects in Z. capensis but not in D. diuca. This is the first field documentation of modulation of intestinal enzymes by diet in birds. Intestinal maltase and sucrase activities were not correlated with seed (vs. insect) intake in either species. In the laboratory, captive birds of both species exhibited similar modulation of membrane-bound intestinal hydrolases when fed on synthetic diets of contrasting carbohydrate and protein composition. Maltase, sucrase, and aminopeptidase-N activities were significantly higher in birds fed on the carbohydrate-free than those on the carbohydrate-containing diet. Activities of the three enzymes were positively correlated. Therefore, this increase probably resulted from nonspecific increases of all enzymes resulting from intake of the carbohydrate-free diet. Principal components analysis separating the effect of diet on specific and on nonspecific modulation revealed that diet had a strong effect on nonspecific activity of intestinal enzymes in both Z. capensis and D. diuca. Diet also significantly affected aminopeptidase-N activities when the effect of diet on nonspecific modulation was removed. Birds fed on the carbohydrate-free, high-protein diet had significantly higher specific aminopeptidase-N activities than those fed on the carbohydrate-containing diet. Our results cast doubts on the notion that dietary flexibility and the plasticity of the gut's enzymes are necessarily correlated and on the general validity of the adaptive modulation hypothesis.
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PMID:Dietary flexibility and intestinal plasticity in birds: a field and laboratory study. 954 55

The effects of the energy and purine content in the diet on mucosal cell mitosis, function, and apoptosis in the small intestine of pigs were investigated in two experiments. In experiment I, three groups of five pigs were first fed a commercial diet that contained 9.1 MJ metabolizable energy (ME) per kilogram dry matter (DM) and 16.4% crude protein. It was followed by the experimental diets for 5 days each starting with an energy deficit (5.8 MJ ME/kg DM; 7% crude protein) followed by a high-energy diet with low purine content (14.1 MJ ME/kg DM; 13.6% crude protein; 460 mg purines/kg), or alternatively an isocaloric high-purine diet (2,160 mg purines/kg). During experimental periods, blood samples were drawn daily through catheters for insulin-like growth factor-I (IGF-I) determination. The animals were killed at the end of the corresponding feeding period and gut tissue samples were collected. In tissue samples, IGF-I and parameters for the characterization of mitosis (thymidine kinase [TK], proliferating-cell nuclear antigen [PCNA]) and differentiation (RNA content, alkaline phosphatase, sucrase) were measured. The degree of apoptosis was determined histologically. In experiment II, five pigs were fitted with simple T-cannula at the distal jejunum. They were fed the three experimental diets consecutively for 7 days each and sucrase and alkaline phosphatase were measured in digesta (four samples daily). IGF-I in blood but not in tissue clearly responded to the energy content of the diet with a decrease during the deficit and an increase in the two high-energy groups. However, purines had no additional effect on IGF-I. TK, PCNA, and gut weight showed an energy effect on mitosis, which was paralleled by increased peripheral IGF-I. Purines led to a further increase of mitosis, but IGF-I and gut weight were not increased. The degree of mitosis was correlated with higher activities of sucrase and alkaline phosphatase and also with the number of apoptotic cells. The enzyme activity increased from the deficit to the high-energy group and was further elevated due to purines. The results from experiment II also confirm these effects of energy and purines, because the activities of the enzymes in digesta decreased during energy deficit, but increased due to energy and in addition to purines.
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PMID:Effects of energy and purines in the diet on proliferation, differentiation, and apoptosis in the small intestine of the pig. 975 Dec 40

We report the characterization of N-linked oligosaccharides on six foreign glycoproteins secreted from the methylotrophic yeast Pichia pastoris. These proteins included: a bacterial enzyme, Bacillus licheniformis alpha-amylase; three fungal enzymes, Saccharomyces cerevisiae invertase, Penicillium minioluteum dextranase, and Mucor pusillus aspartic protease; and two higher eukaryotic proteins, Boophilus microplus (tick) gut antigen and bovine enterokinase catalytic subunit. The carbohydrates on these proteins were observed to vary in size, with Man8GlcNAc2 and Man9GlcNAc2 structures being the most frequently observed species. Substantial amounts of shorter oligomannoside structures were present only on invertase, and longer structures (up to Man18GlcNAc2) were common on aspartic protease and enterokinase. Phosphorylated oligosaccharides were observed on one protein, aspartic protease. Unlike oligosaccharides on glycoproteins secreted from S. cerevisiae, no terminal alpha1,3-linked mannosylation was observed on any of the six P. pastoris-secreted proteins. Changing the growth and induction medium from a minimal salt-based medium to a molasses-based medium had little effect on the size of the oligomannosides. From these results, it is apparent that most foreign proteins secreted from P. pastoris are not subjected to the extensive mannosylation (hyperglycosylation) that commonly occurs in proteins secreted from S. cerevisiae.
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PMID:Variation in N-linked oligosaccharide structures on heterologous proteins secreted by the methylotrophic yeast Pichia pastoris. 979 Aug 82

Epidermal growth factor and related substances mediate their effects on epithelial cells through binding to high-affinity receptors (EGF-R) at their basolateral surface and it is hypothesized that this growth factor system play a major role in gut morphogenesis and maintenance. The current review emphasizes on analyzing the expression and the biochemical characteristics of EGF-R in human fetal gut segments and correlating the biological actions of EGF-R ligands. They appear to be primarily involved in the local regulation of epithelial cell proliferation in which EGF-R are abundant. Alternatively, EGF-R ligands exert some precocious maturative effects by increasing intestinal lactase activity and decreasing brush border hydrolases in colon while they down modulate the expression of segment-specific markers of terminal differentiation such as sucrase, trehalase and glucoamylase in the intestine and chief cell lipase in the stomach. Such effects are consistent with the identification of receptors at the surface of all epithelial cell types, illustrating the modulatory role of EGF on differentiated gut epithelial cells. Comparison with animal models illustrates similar biochemical properties of receptors and underlines physiological aspects specific to human gut development. The relevance for ligand heterogeneity is also discussed and tentatively associated with different delivery pathways or physiological responses.
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PMID:Ontogeny of EGF receptors in the human gut. 988 80

In this study we aimed to elucidate the physiological role of gammadelta intraepithelial lymphocytes (IEL) in the mouse intestine. For this purpose, we used T-cell receptor (TCR) Vgamma4/Vdelta5 transgenic mice (KN 6 Tg: BALB/c background, H-2d), and compared the immunological and physiological characteristics of the intestinal tracts of KN 6 Tg and non-transgenic (non-Tg) littermates. In KN 6 Tg littermates, 95% of small intestinal (SI) and large intestinal (LI) IEL expressed gammadelta TCR, and their TCR was replaced by Tg gammadelta TCR. In these mice, class II major histocompatibility complex (MHC) expression was up-regulated in the SI epithelium, compared with the non-Tg littermates, under specific pathogen-free (SPF) conditions. Competitive reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that the mRNAs of the I-Ealpha chain on the SI epithelial cells was higher in KN 6 Tg than in non-Tg littermates. However, in the LI, class II MHC molecules were not expressed in either KN 6 Tg or non-Tg littermates. The epithelial cell mitotic index in the SI, but not in the LI, was higher in KN 6 Tg than in non-Tg littermates under SPF conditions. However, differentiation markers for SI epithelial cells, such as alkaline phosphatase and disaccharidase (lactase, maltase and sucrase) activities, were similar in KN 6 Tg and non-Tg littermates. MHC class II molecule expression on the SI epithelium was absent in germ-free (GF) Tg mice, but was induced under SPF conditions, coinciding with the increase of interferon-gamma (IFN-gamma) mRNA in gammadelta TCR SI-IEL. These findings suggest that gammadelta TCR IEL regulate epithelial cell regeneration and class II MHC expression, but not cell differentiation in the SI. However, these functions were not observed in the gammadelta TCR IEL in the LI. In addition, the activation step in the gammadelta TCR SI-IEL is dependent on the presence of gut microflora.
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PMID:Physiological roles of gammadelta T-cell receptor intraepithelial lymphocytes in cytoproliferation and differentiation of mouse intestinal epithelial cells. 1044 10

Modulation of gut function is important in an ecological and evolutionary context because it likely determines what food items an animal can and cannot eat. We examined how diet affects activity of digestive enzymes in an omnivorous bird, the pine warbler (Dendroica pinus). Pine warblers were fed insect-based, fruit-based, and seed-based diets for approximately 54 d. We then measured activity of amylase, maltase, sucrase, aminopeptidase-N, trypsin, chymotrypsin, carboxypeptidase A, carboxypeptidase B, pancreatic lipase, and carboxyl ester lipase. We predicted that carbohydrase activities would be highest in birds fed the diet highest in carbohydrates (fruit based), protease activities would be highest in those fed the diet highest in protein (insect based), and lipase activities would be highest in those fed the diets highest in lipid (insect based and seed based). Also, we predicted that pine warblers would exhibit greater dietary modulation of enzyme activity than reported for a less omnivorous congener, the yellow-rumped warbler (Dendroica coronata). All predictions were upheld, supporting the hypothesis that pine warblers modulate the activity of digestive enzymes in proportion to demand from substrates in the diet.
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PMID:An experimental test of dietary enzyme modulation in pine warblers Dendroica pinus. 1052 25

This study investigates the effects of ileal autotransplantation on morphology, crypt cell proliferation, and brush border disaccharidases of the remaining jejunoileum and colon in growing pigs with 75% proximal small bowel resection. Resection was performed on 30 pigs, of which 15 underwent an autotransplantation of the remaining ileum. The autotransplanted pigs showed reduced weight gain and remnant ileal length when compared to the resected controls. In the autotransplanted pigs, small bowel diameter and weight, mucosal weight and protein content, villus height and surface area, crypt depth, and the number of proliferating crypt cells were reduced similarly both in the intact jejunum and in the autotransplanted ileal remnant. Autotransplantation also decreased the number of proliferative crypt cells of the colon. Specific activities of maltase and sucrase tended to increase in the autotransplanted ileal remnant, whereas the total enzyme activities decreased. These results suggest that ileal autotransplantation disturbs postresectional adaptation of the remaining gut.
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PMID:Synchronous ileal autotransplantation impairs adaptation of remaining gut in pigs with proximal small bowel resection. 1057 61


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