Chitin
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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.
The peritrophic membrane in Acarus siro L. (Acari: Acaridae) is produced by distinct cells located in the ventriculus. In this study, the chitin inside the peritrophic membrane was detected using wheat germ-lectin conjugated with colloidal gold (10 nm). The chitin fibrils of the peritrophic membrane were a target for chitin effectors, including 1) chitinase, which hydrolyzes chitin fibers inside the peritrophic membrane; 2) calcofluor, which binds to chitin and destroys the peritrophic membrane mesh structure; and 3) diflubenzuron, which inhibits chitin synthesis. In addition, soybean trypsin protease inhibitor (STI) and cocktails of chitinase/calcofluor, diflubenzuron/calcofluor and chitinase/STI were tested. These compounds were supplemented in diets and an increase of population initiated from 50 individuals was observed after 21 d of cultivation. Final A. siro densities on experimental and control diets were compared. The chitin in the peritrophic membrane was determined to be a suitable target for novel acaricidal compounds for suppressing the population growth of A. siro. The most effective compounds were calcofluor and diflubenzuron, whereas the suppressive effects of chitinase and STI were low. The failure of chitinase could be due to its degradation by endogenous proteases. The combination of chitinase and STI suppressed A. siro population growth more effectively than when they were tested in oral admission separately. The combinations of calcofluor/chitinase or calcofluor/difluorbenzuron showed no additive effects on final A. siro density. The presence of chitin in peritrophic membrane provides a target for novel acaricidal compounds, which disrupt peritrophic membrane structure. The suitability of chitin effectors and their practical application in the management of stored product mites is discussed.
Acidic chitinase (Chia) has been implicated in asthma, allergic inflammations, and food processing. We have purified Chia enzymes with striking acid stability and protease resistance from chicken and pig stomach tissues using a chitin column and 8 M urea (urea-Chia). Here, we report that acetic acid is a suitable agent for native Chia purification from the stomach tissues using a chitin column (acetic acid-Chia). Chia protein can be eluted from a chitin column using 0.1 M acetic acid (pH 2.8), but not by using Gly-HCl (pH 2.5) or sodium acetate (pH 4.0 or 5.5). The melting temperatures of Chia are not affected substantially in the elution buffers, as assessed by differential scanning fluorimetry. Interestingly, acetic acid appears to be more effective for Chia-chitin dissociation than do other organic acids with similar structures. We propose a novel concept of this dissociation based on competitive interaction between chitin and acetic acid rather than on acid denaturation. Acetic acid-Chia also showed similar chitinolytic activity to urea-Chia, indicating that Chia is extremely stable against acid, proteases, and denaturing agents. Both acetic acid- and urea-Chia seem to have good potential for supplementation or compensatory purposes in agriculture or even biomedicine.
- MeSH
- chitin chemie metabolismus MeSH
- chitinasy chemie metabolismus MeSH
- kur domácí MeSH
- kyselina octová chemie MeSH
- prasata MeSH
- vazba proteinů MeSH
- žaludek enzymologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
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.
