Search results for "Chitin"

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.…

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…

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…

Studies on zymogenicity and solubilization of chitin synthase from Candida albicans

1985

The zymogenic form of the chitin synthase present in mixed membrane preparations was extracted by digitonin treatment. The residual extracted membranes exclusively retained the basal activity. Trypsin activation of the zymogenic form of the enzyme did not modify the digitonin solubilization characteristics of the original zymogenic form, suggesting significant differences between ‘in vivo’ activation of chitin synthase and that carried out by trypsin ‘in vitro’.

Effect of digitonin on membrane-bound and chitosomal chitin synthetase activity in protoplasts from yeast cells ofCandida albicans

1993

The effect of digitonin on chitin synthetase present in membrane (MMF) and cytoplasmic fractions (chitosomes) (CF) from C. albicans yeast protoplasts has been determined. The zymogen is preferentially, but not exclusively, solubilized by digitonin from MMF. Centrifugation of distinct solubilized preparations, containing either zymogen, in vivo active enzyme and/or trypsin activated enzyme, on linear sucrose gradients suggests that both zymogen and trypsin activated enzyme sediment slightly slower than the active enzyme, pointing out differences between the activation processes in vivo and in vitro or, alternatively, that both enzyme activities (active in vivo and zymogenic) correspond to di…

Inmunidad Innata en Esclerosis Múltiple Progresiva: Papel de la Chitinase 3-like 1

2020

Introducción: La esclerosis múltiple (EM) es una enfermedad heterogénea en la que coexisten dos fenómenos: la inflamación, que se manifiesta en forma de brotes, y la progresión sostenida de la discapacidad. Es necesario identificar biomarcadores que permitan detectar la neurodegeneración subyacente a la progresión desde el inicio, pues se pone de manifiesto de forma tardía. La Chitinase 3-like 1 (CHI3L1) se ha relacionado con la progresión en la EM, pero su papel en la patogenia de la enfermedad es todavía desconocido. Objetivos: En este trabajo, estudiamos los niveles de CHI3L1 y de la Cadena ligera de Neurofilamento (NfL) en el líquido cefalorraquídeo (LCR) de pacientes con EM y analizamo…

Cell wall composition and protoplast regeneration in Candida albicans

1983

The transition of blastospores to the mycelial phase in Candida albicans was induced after the blastospores were kept at 4°C for several hours and then transferred to a fresh medium prewarmed at 37°C. Glucan was the most abundant polymer in the wall in the two morphogenetic forms but the amount of chitin was higher in the mycelial form than in blastospores. Efficient protoplasting required reducing agents and proteases together with β-glucanases (zymolyase). Protein synthesis in regenerating protoplasts was initiated after about 30 min. Chitin synthetase, initially very low, was incorporated in important amounts into cell membranes mainly in a zymogenic state. After a few hours chitin was t…

YKL-40 as a predictor of mortality after acute coronary syndrome

2020

Hydrolytic enzyme activity of Paenibacillus sp. strain B2 and effects of the antagonistic bacterium on cell integrity of two soil-borne pathogenic fu…

2000

Paenibacillus sp. strain B2, isolated from the mycorrhizosphere of Sorghum bicolor and having an antagonistic activity towards soil-borne fungal pathogens, possessed extracellular cellulolytic, proteolytic, chitinolytic and pectinolytic enzyme activities. The eventual role of these lytic enzymes in cellular interactions between Paenibacillus sp. strain B2 and Phytophthora parasitica and Fusariumoxysporum was investigated by electron microscopy and molecular cytology. Electron microscopic observations showed that the presence of Paenibacillus sp. strain B2 resulted in disorganisation of cell walls and/or cell contents of P. parasitica and F. oxysporum. However, when P. parasitica was treated…