Search results for "Glycoside Hydrolases"
showing 10 items of 33 documents
Differential expression of the invertase-encoding SUC genes in Saccharomyces cerevisiae
1992
Invertase (INV) is encoded in Saccharomyces cerevisiae by a family of genes, comprising SUC1-SUC5 and SUC7. Production of INV is highly variable, dependent on the strain and SUC gene present in the cell. The differences in INV production derive from the structure of the genes or are dependent on the genetic background of the strain. Centromeric plasmids (based on YCp50) carrying one of the SUC genes (except SUC7) were introduced into a strain (SEY2101) lacking SUC genes. The INV produced by the transformants was dependent on the individual SUC genes, and correlated with INV mRNA levels. Plasmids in which SUC2 had been placed under control of promoters from the other SUC genes, were used to …
The mucopolysaccharidoses: Inborn errors of glycosaminoglycan catabolism
1976
The mucopolysaccharidoses are genetic disorders of glycosaminoglycan metabolism. Patients with these diseases accumulate within the lysosomes of most tissues excessive amounts of dermatan and/or heparan sulfates, or of keratan sulfate. The clinical consequences of such glycosaminoglycan storage range from skeletal abnormalities to cardiovascular problems, and to motor and mental retardation. In all mucopolysaccharidoses, except Morquio disease, an excessive accumulation of sulfate-labeled glycosaminoglycans has been demonstrated in fibroblasts cultured from the patient's skin. It was subsequently shown that this was due to the deficiency of specific proteins which were named "corrective fac…
Quantitation of Free and Glycosidically Bound Volatiles in and Effect of Glycosidase Addition on Three Tomato Varieties (Solanum lycopersicumL.)
2007
The volatile fractions of three tomato cultivars (p73, Jorge, and Durinta) were studied in both free and glycosidically bound forms. The possibility of increasing the concentration of free volatile compounds by adding selected glycosidases was also tested. The free volatile fraction (FVF) of tomato juice was directly determined by headspace solid-phase microextraction (SPME). To analyze the glycosidically bound fraction (GBF), tomato juice samples were extracted with C18 cartridges and the resulting glycoside extracts were enzymatically hydrolyzed. The released aglycons were determined by headspace SPME. Of these compounds, six were not previously reported to belong to the tomato GBF. The c…
Microbial and chemical origins of the bactericidal activity of thermally treated yellow mustard powder toward Escherichia coli O157:H7 during dry sau…
2010
Abstract Work examines the origin of bactericidal activity in mustard flour and explores the relative contribution from starter cultures, E. coli O157:H7 itself and other sources. Bacteria can degrade naturally occurring glucosinolates in mustard and form isothiocyanates with antimicrobial activity. In the present work, 24 starter cultures (mostly from commercial mixtures) were screened for their capacity to decompose the glucosinolate, sinalbin. The most active pair, Pediococcus pentosaceus UM 121P and Staphylococcus carnosus UM 123M, were used together for the production of dry fermented sausage contaminated with E. coli O157:H7 (~ 6.5 log CFU/g). They were compared to industrial starters…
Phenotype traits associated with different alleles at the RPS5 locus in Saccharomyces cerevisiae
1992
The RPS5 gene has been characterised through its ability to reduce invertase production by the SUC5 gene. In this paper we show that RPS5 acts by maintaining low levels of SUC5 mRNA. We also show that RPS5 acts on the SUC1 and SUC4 genes but not on SUC2 and SUC3, which are members of the SUC family. RPS5 also shows a pleiotropic effect on the amount of mitochondrial cytochromes.
Molecular events associated with glucose repression of invertase in Saccharomyces cerevisiae.
1986
When S. cerevisiae growing in the presence of glucose (repressive condition) was shifted to higher temperatures, invertase was secreted. This secretion required protein synthesis, but was independent of RNA formation (Mormeneo & Sentandreu 1982). In addition accumulation of invertasespecific messenger RNA occurred in the absence of protein synthesis but was expressed only after synthesis of protein. Invertase mRNA was continuously synthesized under repressive conditions and the levels of this mRNA were regulated by the presence of glucose. The hexose regulated the concentration of this mRNA at the level of transcription and/or by sensitization of this messenger RNA. The expression of the in…
DNase I sensitivity of the chromatin of the yeast SUC2 gene for invertase.
1986
The DNase I sensitivity of chromatin of the yeast SUC2 gene, which encodes two forms of invertase, has been studied both in the genome and in a multicopy plasmid carrying the gene and its flaking sequences. Whereas little if any difference in the DNase I sensitivity of the flanking regions was found between the repressed and the derepressed states, derepression of the gene was accompanied by a large increase in the sensitivity of the transcribed region. A well-defined DNase I hypersensitive site was found centered at approximately 120 bp downstream from the end of the coding region. This site seems to be flanked in the 3' non-coding region by strictly positioned nucleosomes, and the structu…
The shell-forming proteome of Lottia gigantea reveals both deep conservations and lineage-specific novelties
2013
19 pages; International audience; Proteins that are occluded within the molluscan shell, the so-called shell matrix proteins (SMPs), are an assemblage of biomolecules attractive to study for several reasons. They increase the fracture resistance of the shell by several orders of magnitude, determine the polymorph of CaCO(3) deposited, and regulate crystal nucleation, growth initiation and termination. In addition, they are thought to control the shell microstructures. Understanding how these proteins have evolved is also likely to provide deep insight into events that supported the diversification and expansion of metazoan life during the Cambrian radiation 543 million years ago. Here, we p…
Genetic rearrangements in the pathogenicity locus of Clostridium difficile strain 8864 – implications for transcription, expression and enzymatic act…
1998
The pathogenicity locus (PaLoc) of Clostridium difficile isolate 8864 was investigated to locate genetic rearrangements that would explain the exceptional pathogenicity of this particular isolate. Two major changes were defined: an insertion of 1.1 kb between the two genes tcdA and tcdE, coding for the enterotoxin and an accessory protein of unknown function, respectively, and a deletion of 5.9 kb encompassing the 3' ends of tcdA and tcdC. Transcription of the tcdA-E genes is severely affected by both rearrangements, explaining the demonstrated complete lack of TcdA polypeptide. We present a model of coordinate, growth-related transcription of the tcdA-E genes that confirms our previous fin…
The second component of human complement: Use of glycosidases and glucosylation to distinguish the two forms
1988
Abstract The two forms of human plasma C2 that were described in the preceding report (1) were investigated for their functional and biochemical differences. Incubation with the neuraminidase (NAN'dase) of Clostridium perfringens at 37°C resulted in a four- to fivefold increase in the hemolytic activity of both forms. The increase in activity was different than the increase caused by treatment with iodine. The mechanism of increased activity of NAN'dase-treated C2 was the generation of increased molecules of activated C3 (C3b), resulting in more molecules of C5 binding to (C4b, 2a, 3b)n. Removal of N-acetyl-neuraminate from C2 did not alter its binding to a cationic exchanger. Nonenzymatic …