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:3.2.1.20 (alpha-glucosidase)
4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

As part of a study of virulence gene regulation in Streptococcus pneumoniae, we have identified a gene encoding a homologue of the staphylococcal catabolite control protein CcpA in the pneumococcal genome sequence. The pneumococcal protein, designated RegM, has significant similarity to members of the LacI/GalR family of bacterial regulatory proteins. S. pneumoniae D39 derivatives with insertion-duplication or deletion mutations in regM were significantly attenuated in virulence with respect to the wild-type strain. In defined media containing either sucrose or lactose as sole carbon sources, the in vitro growth rates of D39 and the regM mutants were essentially the same. However, in the presence of galactose the regM mutants grew significantly faster than the wild-type strain, whereas growth rates were significantly lower in the presence of glucose or maltose. These data are consistent with the involvement of regM in the catabolism of carbohydrates in S. pneumoniae. RegM was a repressor of both alpha-glucosidase and beta-galactosidase activities in S. pneumoniae, but unlike the situation in certain other bacteria, it does not mediate the repression of these enzymes by glucose. The observed attenuation in virulence was not attributable to poorer growth of the regM mutants in mouse blood ex vivo, but nevertheless, the mutants were rapidly cleared from the blood of infected mice in vivo. The regM mutation had no apparent impact on expression of several confirmed pneumococcal virulence proteins, but studies employing a lacZ transcriptional fusion construct indicated that mutation of regM resulted in a significant reduction in transcription of the capsular polysaccharide biosynthesis locus (cps). Thus, regM is the first gene outside of the cps locus to be implicated in regulation of capsular gene expression.
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PMID:Role of RegM, a homologue of the catabolite repressor protein CcpA, in the virulence of Streptococcus pneumoniae. 1222 70

The development of immune-mediated diabetes in BB rats may involve a defect of the gastrointestinal tract (GI), as suggested by increased gut permeability. This study aimed at measuring invertase, maltase, lactase, and peroxidase activities in the duodenum of diabetesprone BioBreeding (BBdp) rats and control BioBreeding rats (BBc) given free access to NIH-07 diet up to the time of killing at 60 66 d of age. After washing the entire small intestine, the duodenal mucosa was scraped off in the first 5-cm segment from the pylorus and frozen in distilled water. Invertase, maltase, and lactase activities were measured by monitoring the conversion of [U-(14)C]sucrose, [U-(14)C]maltose, and [D-[1-(14)C]glucose] lactose to radioactive hexoses, which were phosphorylated in the presence of adenosine triphosphatase and yeast hexokinase and then separated from their precursor by ion-exchange chromatography. Peroxidase activity was measured by a spectrophotometric procedure. In the BBdp rats, the activity of invertase, maltase, and lactase averaged, respectively, 70.2 +/- 4.4, 81.2 +/- 4.3, and 75.7 +/- 4.1% (n = 16 and p < 0.001 in all cases) of the control values found in BBc rats of the same sex. Inversely, after exclusion of two female BBc rats with abnormally high plasma D-glucose concentration, the activity of peroxidase in the BBdp rats averaged 157.4 +/- 20.0% (n = 16; p < 0.02) of the mean control value recorded in BBc rats of the same sex (100.0 +/- 9.3%; n = 14). These findings are compatible with the view that a proinflammatory state of the GI associated with compromise function may precede the occurrence of pancreatic insulitis in BBdp rats and, possibly, human subjects with type 1 diabetes.
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PMID:Invertase, maltase, lactase, and peroxidase activities in duodenum of BB rats. 1262 29

The suitability of various nectar and honeydew sugars as a food source for the polyphagous ant species M. rubra (L.) was studied. The sugars used included monosaccharides (fructose, glucose, galactose, mannose, rhamnose), disaccharides (sucrose, maltose, trehalose, melibiose, lactose) and trisaccharides (melizitose, raffinose, erlose). Single-sugar solutions were tested on ant workers in a long-term laboratory bioassay in which acceptance of the solutions and ant survival were recorded. The acceptance of the sugars was confirmed in a second bioassay in which feeding time was established. Enzymatic hydrolysis of sucrose, maltose and melibiose was investigated through HPLC analyses of workers fed these disaccharides. Sugar acceptance and feeding time were related to ant survival. Considering the monosaccharide units of which the sugars are composed, fructose seems especially suitable as a short-term energy source, while glucose appears to be used both directly and for storage. The presence of a galactose unit appears to reduce sugar suitability. It is suggested that the workers possess invertase and maltase and to a lesser degree also galactosidase. The gustatory perception is correlated with the profitability of sugars in further metabolic processes.
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PMID:Gustatory perception and metabolic utilization of sugars by Myrmica rubra ant workers. 1269 2

Larval and adult Psacothea hilaris feed on mulberry wood and leaves, respectively. High levels of endogenous activity against the major dietary carbohydrates, cellulose, hemicellulose, starch and soluble sugars were secreted in the gut of larvae and adults. Activity against pectin was also high and multiple polygalacturonase (EC 3.2.1.15) components were secreted in the gut of larvae. One glycanase component, beta-EG1, which was primarily an endo-beta-1,4-glucanase (EC 3.2.1.4) and another, beta-EG2, which was mostly an endo-beta-1,4-xylanase (EC 3.2.1.8), were also secreted, while at least four additional components hydrolysed laminarin, lichenin and crystalline cellulose. The beta-glycosidase component beta-GD1 was associated with most of the beta-mannosidase (EC 3.2.1.25) and beta-xylosidase (EC 3.2.1.37) activity secreted in the gut of larvae, while another, beta-GD2, was a beta-glucosidase (EC 3.2.1.21), the activity of which was directed against cellobiose and other beta-linked disaccharides, and a beta-fucosidase (EC 3.2.1.38). A beta-galactosidase (EC 3.2.1.23), which did not hydrolyse lactose, was also secreted, as were distinct beta-N-acetylhexosaminidase (EC 3.2.1.52), trehalase (EC 3.2.1.28), alpha-L-arabinosidase (EC 3.2.1.55), alpha-galactosidase (EC 3.2.1.22) and a minimum of four alpha-glucosidase (EC 3.2.1.20) components, one of which was also likely to be associated with a peak of alpha-mannosidase (EC 3.2.1.24) activity. The alpha-glucosidase components varied in their specificity for alpha-linked disaccharides, but none was active against sucrose, which was hydrolysed by a beta-fructofuranosidase (EC 3.2.1.26) component. Overall average levels of activity in larvae were twice those of adults, but the secretion of individual carbohydrases in both was not regulated in response to the relative abundance of particular carbohydrate components in their respective diets.
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PMID:Diet and carbohydrate digestion in the yellow-spotted longicorn beetle Psacothea hilaris. 1277 Apr 76

A simple method, easy to perform during an endoscopic procedure, fast and inexpensive, that allows detecting deficiencies in lactase, sucrase or maltase activities is presented. Briefly, method consists in placing a duodenal biopsy sample in an adequate vial containing lactose, sucrose or maltose solution during a few minutes, and then, adding a few drops of a glucose reactive from commercial origin. Presence of any enzymatic activity is demonstrated when released glucose from any of the disaccharides chosen reacts with the second reactive, turning solution to a red colour. Its utility is discussed and compared with other diagnostic methods.
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PMID:[A simple method to detect disaccharides deficiency]. 1470 98

We characterized the role of catabolite control protein A (ccpA) in the physiology and virulence of Streptococcus pneumoniae. S. pneumoniae has a large percentage of its genome devoted to sugar uptake and metabolism, and therefore, regulation of these processes is likely to be crucial for fitness in the nasopharynx and may play a role during invasive disease. In many bacteria, carbon catabolite repression (CCR) is central to such regulation, influencing hierarchical sugar utilization and growth rates. CcpA is the major transcriptional regulator in CCR in several gram-positive bacteria. We show that CcpA functions in CCR of lactose-inducible beta-galactosidase activity in S. pneumoniae. CCR of maltose-inducible alpha-glucosidase, raffinose-inducible alpha-galactosidase, and cellobiose-inducible beta-glucosidase is unaffected in the ccpA strain, suggesting that other regulators, possibly redundant with CcpA, control these systems. The ccpA strain is severely attenuated for nasopharyngeal colonization and lung infection in the mouse, establishing its role in fitness on these mucosal surfaces. Comparison of the cell wall fraction of the ccpA and wild-type strains shows that CcpA regulates many proteins in this compartment that are involved in central and intermediary metabolism, a subset of which are required for survival and multiplication in vivo. Both in vitro and in vivo defects were complemented by providing ccpA in trans. Our results demonstrate that CcpA, though not a global regulator of CCR in S. pneumoniae, is required for colonization of the nasopharynx and survival and multiplication in the lung.
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PMID:Catabolite control protein A (CcpA) contributes to virulence and regulation of sugar metabolism in Streptococcus pneumoniae. 1632 38

A new Clostridium strain was isolated on starch at 60 degrees C. Starch, pullulan, maltotriose, and maltose induced the synthesis of alpha-amylase and pullulanase, while glucose, ribose, fructose, and lactose did not. The formation of the amylolytic enzymes was dependent on growth and occurred predominantly in the exponential phase. The enzymes were largely cell bound during growth of the organism with 0.5% starch, but an increase of the starch concentration in the growth medium was accompanied by the excretion of alpha-amylase and pullulanase into the culture broth; but also by a decrease of total activity. alpha-Amylase, pullulanase, and alpha-glucosidase were active in a broad temperature range (40 to 85 degrees C) and displayed temperature optima for activity at 60 to 70 degrees C. During incubation with starch under aerobic conditions at 75 degrees C for 2 h, the activity of both enzymes decreased to only 90 or 80%. The apparent K(m) values of alpha-amylase, pullulanase, and alpha-glucosidase for their corresponding substrates, starch, pullulan, and maltose were 0.35 mg/ml, 0.63 mg/ml, and 25 mM, respectively.
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PMID:Thermostable amylolytic enzymes from a new clostridium isolate. 1634 92

The intestine of newborn pigs develops rapidly during the first days postpartum. We investigated if feeding milk replacer (infant formula) as an alternative to colostrum has compromising effects on nutrient digestive function in the neonatal period. Nineteen piglets born at term were assigned to one of four treatments: (1) newborn controls; (2) natural suckling for 24 h; (3) tube-fed formula for 24 h; (4) tube-fed porcine colostrum for 24 h. All three fed groups showed significant increases in small-intestinal and colonic weights, villous heights and widths, maltase and aminopeptidase A activities, and decreases in dipeptidylpeptidase IV activity, relative to newborn pigs. Following oral boluses of mannitol, lactose or galactose, formula-fed pigs showed significantly reduced plasma levels of mannitol and galactose compared with colostrum-fed pigs. Activity of intestinal inducible NO synthase and plasma levels of cortisol were significantly increased, whereas intestinal constitutive NO synthase and alpha-tocopherol were decreased in formula-fed pigs compared with colostrum-fed pigs. Although formula-fed pigs only showed minor clinical signs of intestinal dysfunction and showed similar intestinal trophic responses just after birth, as those fed colostrum, lactose digestive capacity was markedly reduced. We conclude that formula-feeding may exert detrimental effects on intestinal function in neonates. Formula-induced subclinical malfunction of the gut in pigs born at term was associated with altered NO synthase activity and antioxidative capacity.
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PMID:Formula-feeding reduces lactose digestive capacity in neonatal pigs. 1676 28

We analysed the spatio-temporal sequence of events concerning the morphology, physiology and ecology of the gut of piglets during the 2 weeks following weaning, in order to provide a limited number of variables that could be relevant markers of the gut post-weaning changes. An experiment was conducted on sixty piglets fasted for 2 d, then administered a weaning diet with a moderate or a high content of wheat using controlled gastric feeding, and slaughtered at different time-points post-weaning. Sixty-nine variables were analysed by principal component analysis. The results showed that the temporal changes induced in the gut by weaning can be divided into two periods: an acute period happening immediately after weaning, followed after day 5 by a more progressive adaptative and maturational phase. The main factors of this adaptation were the refeeding process and the time, while the diet per se had little influence. The villus length, lactose activity, macromolecule fluxes across the jejunum and the plasma cholecystokinin were proposed as markers of the acute phase. Ths mass of the jejunum, the weight of the pancrease, the content of stomach, the trypsin activity and the theophyl-line-induced secretion in jejunum were related to the re-feeding. Markers proposed to follow the gut maturation were the maltase activity, the glucose absorption and the basal resistance in the ileum, the lactobacilli and enterococci in the colon, and the pH of colonic and caecal contents. These markers might be helpful to design suitable diets to limit posts-weaning gut disorders in pigs.
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PMID:Main intestinal markers associated with the changes in gut architecture and function in piglets after weaning. 1721 59

A method is described for the measurement of dietary fibre, including resistant starch (RS), non-digestible oligosaccharides (NDO) and available carbohydrates. Basically, the sample is incubated with pancreatic alpha-amylase and amyloglucosidase under conditions very similar to those described in AOAC Official Method 2002.02 (RS). Reaction is terminated and high molecular weight resistant polysaccharides are precipitated from solution with alcohol and recovered by filtration. Recovery of RS (for most RS sources) is in line with published data from ileostomy studies. The aqueous ethanol extract is concentrated, desalted and analysed for NDO by high-performance liquid chromatography by a method similar to that described by Okuma (AOAC Method 2001.03), except that for logistical reasons, D-sorbitol is used as the internal standard in place of glycerol. Available carbohydrates, defined as D-glucose, D-fructose, sucrose, the D-glucose component of lactose, maltodextrins and non-resistant starch, are measured as D-glucose plus D-fructose in the sample after hydrolysis of oligosaccharides with a mixture of sucrase/maltase plus beta-galactosidase.
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PMID:An integrated procedure for the measurement of total dietary fibre (including resistant starch), non-digestible oligosaccharides and available carbohydrates. 1761 81


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