Search results for "cell wall"
showing 10 items of 226 documents
Killer Toxins of Yeasts: Inhibitors of Fermentation and Their Adsorption.
2019
The killer toxin (KT 28), a glycoprotein of Saccharomyces cerevisiae strain 28, was almost completely adsorbed by bentonite, when applied at a concentration of 1 g per liter. No significant differences were found between several types of bentonite. Killer toxin KT 28 is similarly adsorbed by intact yeast cells or by a commercial preparation of yeast cell walls that has been recommended to prevent stuck fermentations. An investigation of the cell wall fractions revealed that the toxin KT 28 was mainly adsorbed by mannan, that removed the toxin completely. The alkali-soluble and the alkali-insoluble β-1,3- and β-1,6-D-glucans lowered the toxin concentration to one tenth of the original amount…
Analysis of the proteins involved in the structure and synthesis of the cell wall of Ustilago maydis
2008
Abstract A study of the proteins involved in the synthesis and structure of the cell wall of Ustilago maydis was made by in silico analysis of the fungal genome, with reference to supporting experimental evidence. The composition of the cell wall of U. maydis shows similarities with the structural composition of the walls of Ascomycetes, but also shows important differential features. Accordingly, the enzymes involved in the synthesis of the U. maydis wall polysaccharides chitin and β-1,6 glucans displayed some differential characteristics. The most salient difference in protein composition was the predicted absence of Pir proteins, an important class of proteins present in the Ascomycetes.…
A xyloglucan from persimmon fruit cell walls
1998
Persimmon (Diospyros kaki L.) fruit cell walls have been shown to contain a high proportion of xyloglucan. This hemicellulosic polysaccharide appears to play a crucial role in the softening process that accompanies fruit ripening. In the present work, xyloglucan from persimmon fruit cell walls was extracted, purified and chemically characterized from alkali-extracted hemicelluloses. Monosaccharide analysis of purified xyloglucan showed a molar ratio of Glc:Xyl:Gal:Fuc of 10.0:6.0:3.4:1.4. Linkage analysis showed a high proportion of terminal residues, indicating a low degree of polymerization of side-chains.
Separation of chitosomal chitin synthetase from cell-free extracts ofNeurospora crassa “Slime” variant agglutinated with concanavalin A
1989
Cell-free extracts of the wall-less slime variant ofNeurospora crassa were treated with concanavalin A (Con A); this treatment caused a massive agglutination of the particulate structures in the cell-free homogenate, although most (73%) of the chitin synthetase initially present in the cell-free extract remained in the supernatant obtained after sedimentation of the lectin-flocculated material. This chitin synthetase showed the sedimentation properties of chitosomes (unique microvesicular structures) and failed to bind [3H]Con A. A significant percentage (42%) of the chitin synthetase activity associated with the Con A-flocculated material probably corresponds to mechanically trapped chitos…
Cell wall xyloglucan incorporation by xyloglucan endotransglucosylase/hydrolase in pine hypocotyls
2004
Abstract In the present study, we have examined the incorporation of labelled xyloglucan oligosaccharides into the cell wall xyloglucan of pine hypocotyl sections, and the effect of plant hormones on the incorporation and on XTH enzyme activity (EC 2.4.1.207). Xyloglucan heptasaccharide [ 3 H ]XXXGol was absorbed, transported and incorporated into the cell wall xyloglucan of de-rooted pine hypocotyls. Incorporation of [ 3 H ]XXXGol into soluble and cell wall xyloglucan was induced by IAA, brassinolides and XXXG in pine hypocotyl segments. A relationship between growth induction, by IAA, brassinolides and XXXG, and both soluble and cell wall-bound XTH was found. We suggest that IAA induced-g…
Chitin: A Structural Biopolysaccharide with Multiple Applications
2014
Chitin is a naturally occurring fibre-forming polymer that plays a protective role in many lower eukaryotes similar to that of cellulose in plants. Chemically it is a long-chain unbranched polysaccharide made of N-acetylglucosamine residues linked through β-1,4 covalent bonds; it is the second most abundant organic compound in nature, after cellulose. Taking into account the role played by chitin in different biological structures (i.e. fungal cell walls, insect peritrophic matrix, insect and crustacean cuticles, eggshells from nematodes, cyst wall of protozoa), its metabolism (biosynthesis and degradation) is essential for different morphogenetic events. Absent in vertebrates and plants, c…
Über die kinetik und den mechanismus der biosynthese der cellulose in den höheren pflanzen (nach versuchen an den samenhaaren der baumwolle)
1966
Abstract The quantity of cellulose synthesized on growing cotton bolls and the corresponding degree of polymerisation have been measured as a function of time. It was found that the biosynthesis proceeds in two distinct stages, beginning with a slow process yielding the “primary” cellulose with a non-uniform degree of polymerisation of about 2000–6000 followed by a more rapid process yielding a large amount of “secondary cellulose” with a high and uniform degree of polymerisation of about 14000 (mol. wt. 2.3·106). During the second stage the degree of polymerisation is independent of time. It is shown that the two kinds of cellulose correspond to the primary and secondary cell wall. In orde…
Neuere untersuchungen über größe und größenverteilung der β-glukosidischen ketten nativer cellulosen
1963
Der Polymerisationsgrad Pw der β-glukosidischen Ketten der Cellulose in unbehandelten Baumwollen verschiedener Herkunft liegt etwa zwischen 8500 und 9500. Die Molekulargewichtsverteilung zeigt 3 ausgepragte Maxima beim Polymerisationsgrad 11 500, 5500 und ca. 1500. Das letztere Maximum gehort wahrscheinlich zum Cellulosematerial der Primarwand, wahrend die beiden anderen Maxima dem Material der Sekundarwand angehoren. Die hohe Einheitlichkeit und der grose Mengenanteil des zum hochsten Maximum (bei P = 11 500) gehorenden Celluloseanteils legt es nahe, fur die biochemische Synthese der Cellulose einen POISSONmechanismus oder einen Matritzenmechanismus anzunehmen. Fasercellulosen aus anderen …
The endopolygalacturonase 1 from botrytis cinerea activates grapevine defense reactions unrelated to its enzyumatic activity
2003
A purified glycoprotein from Botrytis cinerea(strain T4), identified as endopolygalacturonase 1 (T4BcPG1) by mass spectrometry analysis, has been shown to activate defense reactions in grapevine (Vitis vinifera cv. Gamay). These reactions include calcium influx, production of active oxygen species, activation of two mitogen-activated protein kinases, defense gene transcript accumulation, and phytoalexin production. Most of these defense reactions were also activated in grapevine in response to purified oligogalacturonides (OGA) with a degree of polymerization of 9 to 20. In vivo, these active OGA might be a part of the released products resulting from endopolygalacturonase activity on plan…
Potencialidades del consorcio microbiano Curvularia kusanoi -Trichoderma pleuroticola como pretratamiento biológico para la degradación de fuentes fi…
2022
Objective. To evaluate the potentiality of the microbial consortium Curvularia kusanoi L7- Trichoderma pleuroticola as biological pretreatment of high fiber sources destined for animal production. Materials and methods. The Strains used where Curvularia kusanoi L7 and Trichoderma pleuroticola. The degradative potential was evaluated through the production kinetics of cellulolytic (endo-1,4-β-glucanase and exo-1,4-β-glucanase) and ligninolytics enzymes (laccase and peroxidase) in solid submerged fermentation of bran wheat and sugarcane bagasse. The growth of the co culture in plates was analyzed. The effect of the consortium on the carbon mineralization of raw wheat straw was determined and …