chitin Dotaz Zobrazit nápovědu
Chitin-glucan complex is a fungal origin copolymer that finds application in medicine and cosmetics. Traditionally, the mycelium of Micromycetes is considered as an industrial chitin-glucan complex source. Basidiomycete Schizophyllum commune submerged cultivation for chitin-glucan complex production was studied. In different S. commune strains chitin-glucan complex composed 15.2 +/- 0.4 to 30.2 +/- 0.2% of mycelium dry weight. Optimized conditions for chitin-glucan complex production (nutrient medium composition in g/l: sucrose - 35, yeast extract - 4, Na2HPO4*12H2O - 2.5, MgSO4*7 H2O - 0.5; medium initial pH 6.5; aeration intensity 21 of air per 11 of medium; 144 hours of cultivation) resulted in 3.5 +/- 0.3 g/l complex yield. Redirection of fungal metabolism from exopolysaccharide synthesis to chitin-glucan complex accumulation was achieved most efficiently by aeration intensity increase. Chitin-glucan complex from S. commune had the structure of microfibers with diameter 1-2 microm, had water-swelling capacity of 18 g/g, and was composed of 16.63% chitin and 83.37% glucan with a degree of chitin deacetylation of 26.9%. S. commune submerged cultivation is a potent alternative to Micromycetes for industrial-scale chitin-glucan complex production.
Methods in enzymology ; Vol. 161
574 s. : il.
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- biochemie
Současný rozvoj v péči o rány spočívá hlavně ve fyziologické podpoře hojení rány. Poté, co infekce rány způsobuje zpoždění hojení rány a zhoršuje tvorbu jizvy, je snaha o to dosáhnout co nejdříve uzávěru rány. Mezi hlavní principy v péči o ránu patří prevence infekce, zajištění vlhkého prostředí, klidu rány a dosažení minimálního jizvení. V této studii jsme sledovali na klinickém mo-delu efekt nového gelu na bázi chitinových nanovláken co se týče kvality a rychlosti hojení. Chitin má některé neobvyklé vlastnosti, které urychlují hojení ran u lidského organismu. Hlavní biochemická působení chitinu a na chitosanu založených materiálů jsou: polymorfonukleární aktivace buněk, aktivace fibroblastů, tvorba cytokinu, obrovskobuněčná migrace a stimulace tvorby kolagenu IV. typu. Výsledky této klinické studie potvrzují, že gel založený na bázi chitinových nanovláken podporuje rychlé a fyziolo-gické hojení různých druhů ran. Navíc se zdá, že působí jako prevence vzniku hypertrofických a keloidních jizev.
Recent progress in wound management is mainly in terms of physiological support for healing. Since infections delay healing and worsen scar formation, there is a desire to achieve closure as soon as possible. The main goals of wound care are prevention of infection, maintenance of a moist environment, protection of the wound and achievement of minimum scar formation. In this study were investigated in a clinical model the effects of a new chitin nanofibrils-based gel on the rate and quality of wound healing. Chitin has some unusual properties which accelerate the healing of wounds in humans. The main biochemical activities of chitin and chitosan-based materials are: polymorphonuclear cell activation, fibroblast activation, cytokine production, giant cell migration and stimulation of type IV collagen synthesis. The results of this clinical study confirm that chitin nanofibrils-based gel promotes rapid and physiological healing of different types of wounds. Moreover, it seems to prevent hypertrophic scarring and keloid scarring.
Chitin exists in yeast cells both as free and bound in a complex with β-1,3/β-1,6-glucan. The formation of covalent links between chitin and β-glucans is catalyzed by the enzymes Crh1 and Crh2, acting as transglycosylases. We found that N-acetyl-chito-oligosaccharides, as well as laminarioligosaccharides, the respective products of partial hydrolysis of chitin, and β-1,3-glucan, interfered with reactions catalyzed by Crh1p and Crh2p in vitro. However, the N-acetyl-chito-oligosaccharides did not influence the growth rate of the yeast, neither did they affect the yeast phenotype, but they prolonged the lag phase. Inhibition of Crh1 and Crh2 in vivo with oligosaccharides derived from chitin leads to an increase of alkali-soluble chitin and a decrease in the amount of chitin linked to β-glucans. In addition, yeast cells growing in the presence of N-acetyl-D-chito-oligosaccharides accumulated more chitin than control cells.
