Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of chronic administration of hydrocortisone during pregnancy on growth and maturation of the foetal gut and pancreas was investigated. Groups of 10- to 11-day pregnant rats were injected with saline or hydrocortisone (50 mg/kg) once a day for 10 days. The pancreas, antrum, and small intestine of newborns (8-10 h after birth) were analysed for various determinants of growth and maturation. The small-intestinal weight and DNA, RNA, and protein were significantly higher in newborns from hydrocortisone-treated animals than those of saline-treated controls. Hydrocortisone treatment resulted in an induction of sucrase and significantly stimulated total lactase activity. After the steroid treatment during pregnancy, the weight of the pancreas and its DNA content in newborns were also significantly elevated when compared with those from saline-treated controls. However, neither pancreatic RNA nor protein content differed significantly between the groups. Antral gastrin content in newborns from hydrocortisone-treated mothers was significantly higher than that from saline-treated controls. Pancreatic gastrin content in newborns was slightly but not significantly reduced after the steroid administration to mothers. It is concluded that glucocorticoids induce growth and maturation of foetal gut and pancreas.
 ...
PMID:Influence of glucocorticoids on prenatal development of the gut and pancreas in rats. 258 7

When incubated at a restrictive temperature, Saccharomyces cerevisiae sec59 mutant cells accumulate inactive and incompletely glycosylated forms of secretory proteins. Three different secretory polypeptides (invertase, pro-alpha-factor, and pro-carboxypeptidase Y) accumulated within a membrane-bounded organelle, presumably the endoplasmic reticulum, and resisted proteolytic degradation unless the membrane was permeabilized with detergent. Molecular cloning and DNA sequence analysis of the SEC59 gene predicted an extremely hydrophobic protein product of 59 kilodaltons. This prediction was confirmed by reconstitution of the sec59 defect in vitro. The alpha-factor precursor, which was translated in a soluble fraction from wild-type cells, was translocated into, but inefficiently glycosylated within, membranes from sec59 mutant cells. Residual glycosylation activity of membranes of sec59 cells was thermolabile compared with the activity of wild-type membranes. Partial restoration of glycosylation was obtained in reactions that were supplemented with mannose or GDP-mannose, but not those supplemented with other sugar nucleotides. These results were consistent with a role for the Sec59 protein in the transfer of mannose to dolichol-linked oligosaccharide.
 ...
PMID:Sec59 encodes a membrane protein required for core glycosylation in Saccharomyces cerevisiae. 265 87

Several secretion-defective variants of invertase from Saccharomyces cerevisiae were generated by replacement of the wild-type signal sequence codons with DNA fragments with random sequences. Strains encoding these proteins failed to grow on medium containing sucrose as the sole source of carbon. The invertase that was made in these strains was found to fractionate with soluble, cytoplasmic proteins, and indirect immunofluorescence confirmed that the mutant invertase was located throughout the cytoplasm. To define the defects in the secretion-defective leader sequences, we selected revertants by requiring growth on sucrose. Surprisingly, most of the reversion events consisted of point changes and duplications in the upstream noncoding portion of the gene. Each of these changes introduced several hydrophobic residues into the nonfunctional leader sequences, suggesting that the defective random leader peptides might simply lack adequate hydrophobicity to be effective signal peptides.
 ...
PMID:Intragenic revertants of yeast invertase variants with secretion-defective leader sequences. 265 96

DNA segments encoding signal peptides from mouse alpha-amylase, yeast acid phosphatase, and yeast invertase were fused in frame to a barley (1-3,1-4)-beta-glucanase cDNA gene and expressed in yeast cells under the control of the phosphoglycerate kinase gene promoter. Pure beta-glucanase is obtained by gel filtration of concentrated yeast cell supernatant. It was shown that the glucanase pre-protein was specifically processed and the mature protein efficiently secreted when the yeast invertase signal sequence directed secretion.
 ...
PMID:Processing and secretion of barley (1-3,1-4)-beta-glucanase in yeast. 267 77

Factors for efficient synthesis of mRNA in vitro and its subsequent translation in cell free lysates from reticulocyte and wheat germ were studied using yeast invertase as a probe. Among various transcription systems tested, containing either SP6, T5, T7 or a bacterial synthetic consensus promoter, the T7 system was superior both from a quantitative and qualitative point of view. Transcription with SP6 polymerase, but not with the other enzymes, resulted in premature transcript termination, which is ascribed to a sensitivity of the SP6 polymerase towards a hairpin loop structure in the invertase coding region. In-frame fusion of the critical DNA sequence to a different gene promoted premature transcription termination of the resulting chimeric template, which in its original form is transcribed correctly. Transcripts with additional sequences 5' upstream of the natural translation start revealed a diminished protein synthesis presumably due to the presence of out of frame ATG codons. In contrast, no influence on translation was found when additional sequences at the 3' end were present or when the stop codon was missing. Capping of transcripts was essential for translation in wheat germ lysates, whereas protein synthesis in reticulocytes was only reduced in the absence of a cap. The influence of polyadenylation on translation was studied using transcripts with engineered poly(A) tracts of different size. Increasing poly(A) chain length abolished translation in vitro in both translation systems. Inhibition was poly(A)-specific and is discussed as interference of the poly(A) sequences with a crucial component(s) of the protein synthesis machinery.
 ...
PMID:Requirements for efficient in vitro transcription and translation: a study using yeast invertase as a probe. 267 76

Several hundred new mutations in the gene (HXK2) encoding hexokinase II of Saccharomyces cerevisiae were isolated, and a subset of them was mapped, resulting in a fine-structure genetic map. Among the mutations that were sequenced, 35 were independent missense mutations. The mutations were obtained by mutagenesis of cloned HXK2 DNA carried on a low-copy-number plasmid vector and screened for a number of different phenotypes in yeast strains bearing chromosomal hxk1 and hxk2 null mutations. Some of these mutants were characterized both in vivo and in vitro; they displayed a wide spectrum of residual hexokinase activities, as indicated by three assays: in vitro enzyme activity, ability to grow on glucose and fructose, and ability to repress invertase production when growing on glucose. Of those that failed to support growth on fructose, only a small minority made normal-size, stable, and inactive protein. Analysis of the amino acid changes in these mutants in light of the crystallographically determined three-dimensional structure of hexokinase II suggests important roles in structure or catalysis for six amino acid residues, only two of which are near the active site.
 ...
PMID:Isolation and characterization of mutations in the HXK2 gene of Saccharomyces cerevisiae. 268 71

A plasmid vector, pYZ1, was constructed which lacks most of the beta-lactamase signal-peptide coding region, but has a unique EcoRI site spanning codons 2 and 3 of the resultant cytoplasmic beta-lactamase derivative. Short quasi-random DNA sequences were cloned into the EcoRI site and Escherichia coli transformants in which some translocation of beta-lactamase across the cytoplasmic membrane was restored were selected by their ability to survive and form colonies on plates containing a low level of ampicillin. About 15-20% of all in-frame inserts restored some beta-lactamase translocation and the salient feature of these sequences was their marked hydrophobicity. These results are discussed in the light of a similar study in which sequences able to function as translocators of invertase in yeast were cloned and analysed (Kaiser et al., 1987).
 ...
PMID:Identification of amino acid sequences that can function as translocators of beta-lactamase in Escherichia coli. 269 95

The effects of Gossypol acetic acid (10 mg/kg b. wt. daily for 15 days), an experimental male antifertility agent and its subsequent withdrawal for another 15 days, on the structure and functions of the rat small intestinal tract have been investigated. Gossypol feeding causes a reduction in body weight and intestinal weight, length, protein, and nucleic acid contents. A 27%-50% reduction in the uptake of glucose, alanine, leucine, and calcium is observed after Gossypol feeding which is found to be reversible after 15 days of withdrawal of the drug. Gossypol also causes a significant reduction in the activities of sucrase, lactase, maltase and alkaline phosphatase in the intestinal homogenates as well as in the purified brush border membrane of the microvillus. A decrease in the maximum of apparent enzyme velocity and no change in the substrate affinity constant in these digestive hydrolases are observed on Gossypol treatment. It also causes a shift in the transition temperature in these enzymes and predictably changes the energy of activation both below and above the temperature of transition, although the Arrhenius expression of the temperature dependence still shows proximity, non-linearity, and is parallel to the control group. These changes are reversed on withdrawal of the drug and during the subsequent recovery period. Recovery experiments also show near identical values in kinetic parameters (Kt and Jmax) of 14C-glucose uptake in jejunal segments both in the presence and absence of Na+ ions. Also, no difference is observed between the control and recovery groups with respect to body and intestinal weight, intestinal length, and DNA, RNA, protein, lactate dehydrogenase and glucose-6-phosphate phosphohydrolase values in the intestinal homogenates. Phospholipid, cholesterol and sialic acid levels in both the groups also show nearly identical values. Molecular mechanism of the effects of Gossypol on brush border membrane-bound enzyme/carrier molecules operation is discussed in view of the kinetic and thermodynamic data obtained.
 ...
PMID:Reversibility of the effects of gossypol acetic acid, an antispermatogenic/antifertility agent on the intestinal structure and functions of male albino rats. 274 9

We evaluated the effect of intestinal anastomosis without resection on gut morphometry (muscle thickness, villus height, and crypt depth), growth indices (DNA, protein, and protein:DNA ratio), and disaccharidase activity (maltase, sucrase, and lactase) in the growing animal. A group of 10 weanling Sprague-Dawley rats at 21 days of age was subjected to intestinal transection and anastomosis in the upper jejunum, 10 cm distal to the ligament of Treitz. A second group of 10 similar rats was used as a control group. All rats were fed a regular diet and kept under the same conditions. They were sacrificed 2 weeks later. Body weight, intestinal weight, and intestinal length measurements were obtained. The intestine was divided into two sections: preanastomotic (section A) and postanastomotic (section B) in the surgery group and equivalent sections A and B in the control group. Specimens were subjected to morphometric evaluation and mucosal scrapings for biochemical analysis. Despite significant weight gain in the control group, there were no differences in intestinal length, intestinal weight, and mucosal weight between the two groups. Muscle thickness, villus height, and crypt depth were significantly increased in the preanastomotic segment. Protein and DNA were also higher in the preanastomotic segment, but the protein:DNA ratio was less affected. There was significantly decreased enzymatic activity in the preanastomotic segment. Intestinal anastomosis has a significant effect on gut growth and maturation in the growing animal and may have important implications in the postoperative management of newborns and infants following intestinal surgery.
 ...
PMID:The effect of intestinal anastomosis on gut growth and maturation. 280 56

Six unlinked loci for invertase structural genes are known in the yeast Saccharomyces cerevisiae: SUC1-SUC5 and SUC7. These genes are similar in structure and expression but not identical. Different yeast strains possess none, one or several of these genes. We have isolated the genes SUC1-SUC5, subcloned them into the multicopy vector YEp24 and compared the expression of the five SUC genes in one recipient strain. SUC2 was isolated by transformation of a suc0 strain with a gene pool and complementation to sucrose fermentation. SUC4 was cloned from a minipool of chromosomal fragments which were shown to contain SUC4 by Southern hybridization. SUC1, SUC3 and SUC5 were isolated using the method of plasmid eviction. A plasmid containing regions flanking SUC4 was integrated next to these SUC genes. The plasmid together with the SUC genes were then cut out of the chromosome using an appropriate restriction endonuclease. The length of chromosomal DNA fragments containing the different SUC genes were 4.8 kb for SUC1, 5.2 kb for SUC2, 4.8 kb for SUC3, 12.8 kb for SUC4 and 17.2 kb for SUC5. Fragments containing the complete SUC genes and the sequences controlling their expression were subcloned into YEp24 and transformed into a strain without any active invertase gene. Invertase activity of transformants was measured after growth repressing (8% glucose) and derepressing (2% raffinose) conditions. As expected from results with strains carrying the individual SUC genes in a chromosomal location, the SUC genes were expressed to a different extent.
 ...
PMID:Cloning and expression on a multicopy vector of five invertase genes of Saccharomyces cerevisiae. 283 91


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>