Chitinase

About: Chitinase is a research topic. Over the lifetime, 4690 publications have been published within this topic receiving 161786 citations. The topic is also known as: 1,4-beta-poly-N-acetylglucosaminidase & poly-beta-glucosaminidase.

Chitinase production by an Arthrobacter sp. lysing cells of Fusarium roseum

Abstract: An Arthrobacter sp. which actively lysed Fusarium roseum was found to liberate chitinase (E.C. 3.2-1.14, chitin glycanohydrolase), an enzyme essential for the hydrolysis of chitin, a major component of fusarial hyphal walls. Factors involved in the production of chitinase were investigated by modifying culture conditions and assaying for enzyme activity. Production occurred on colloidal chitin as well as on native chitin supplemented with yeast extract or peptone. Enzyme production paralleled growth; liberation of enzyme took place during the log phase with the maximum yield being obtained at the stationary phase. Addition of the non-ionic surfactant, polyoxyethylene sorbitan monooleate (Tween 80) increased enzyme yield. An inverse relationship was found between the amount of enzyme produced and the quantity of n-acetyl-glucosamine liberated. The enzyme was generally not produced when grown on various other carbohydrates. These findings suggest that chitinase is inducible and that chitin breakdown is regulated by a repressor-inducer mechanism. Initial hydrolysis rates of colloidal chitin were proportional to the concentration of chitinase used. Optimal pH and temperature for enzyme activity were 4.9 and 50°C, respectively. Purification of the chitinase was obtained by (NH4)2SO4 precipitation followed by DEAE-cellulose and Sephadex chromatography, achieving a 12-fold increase in specific activity.

Chitinase and peroxidase activities are induced in eucalyptus roots according to aggressiveness of Australian ectomycorrhizal strains of Pisolithus sp.

Abstract: Peroxidase and chitinase activities were measured in roots of Eucalyptus globulus spp bicostata Kirkp. during colonization by Pisolithus sp. isolated from under Eucalyptus. Ten fungal isolates, ranging from poor to good root colonizers, were selected to represent a range of ectomycorrhizal aggressivity. The induction of chitinases and peroxidases was strongly related to the aggressiveness of the fungal strain. Only good colonizers, that is strains which rapidly form differentiated ectomycorrhizas, induced a strong response in the plant. Therefore, it can be concluded that these enzymes are not responsible for poor root colonization by the less aggressive strains. The chitinase response of Eucalyptus roots to contact with fungal extracts differed only slightly between weakly and strongly aggressive strains. This suggests that a major component of differential induction observed in vivo is the consequence of root colonization, tissue penetration and the ability to deliver elicitors to the plain print to and during rant colonization

A possible role of chitin in the pathogenesis of asthma and allergy

Abstract: Chitin is the second most abundant polysaccharide in the world; it is found in insects, parasites and fungi. Chitinases break down chitin, and are a part of the defence mechanism against chitin-containing parasites in lower life forms. This review is based on the results of PubMed-searches using the search-terms: chitin, chitinase, allergy and asthma. Research in murine models has proved that chitin is a size-dependent microbial- associated molecular pattern, with the ability to induce an immunological response via pattern recognition receptors. Medium-sized chitin micro-particles (CMPs) have been shown to induce infl ammation, while small-sized CMPs reduce infl ammation. The amount of acidic mammalian chitinase correlates with asthma, and the enzyme has been shown to induce chemokine secretion in murine lungs. The high prevalence of asthma among people working with chitinous substances, such as crabs and fungi, supports the hypothesis that chitin might be an allergen playing a role of signifi cance in the develop- ment of asthma. This new knowledge about chitin and chitinases, combined with the hygiene-hypothesis, may contribute to a model for the pathogenesis of allergic conditions where chitin and chitinases are potential therapeutic targets.