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.

Identification of chitin as a structural component of Giardia cysts.

Abstract: The intestinal parasite Giardia lamblia is a significant cause of diarrheal disease, which is perpetuated by the infective cyst form of the parasite. Although a rational approach to the control of giardiasis would be to inhibit cyst formation, nothing is known of the chemical composition of the cyst wall or of its biosynthesis. In these studies, we have shown that chitin is a major structural component of G. lamblia and G. muris cyst walls. This conclusion is based on the finding that chitinase specifically destroys the cyst wall, as revealed by electron microscopy. The presence of chitin was also shown directly by lectin binding studies. Of 12 lectins with diverse carbohydrate recognition specificity, only the N-acetylglucosamine-specific lectins wheat germ agglutinin, succinylated wheat germ agglutinin, and tomato lectin bound to cyst walls, as shown by fluorescence microscopy and cytochemistry. Wheat germ agglutinin binding was completely abolished by treatment of the cysts with purified chitinase. This effect was specific since it could be prevented by incubating the enzyme with chitin before treatment of the cysts. Treatment of cysts with N-acetyl-beta-glucosaminidase partially inhibited wheat germ agglutinin binding, whereas other glycosidases and proteases had no effect. These findings indicate that chitin is a major structural component of Giardia cyst walls and raise the possibility that inhibitors of chitin synthesis may be of use in preventing encystation and thus controlling spread of the disease. Images

Detection of pathogenesis-related proteins-chitinase and β-1,3-glucanase in induced chickpea

Abstract: Pathogenesis-related (PR) proteins, chitinase and β-1,3-glucanase were extracted from induced chickpea plant and purified by gel filtration. Time-course accumulation of these PR-proteins in induced chickpea plants was significantly (P = 0.05) higher than the control. Maximum activities of these PR-proteins were recorded after three days of inoculation in all induced plants. Thereafter, the activity decreased progressively. Two chitinases and three β-1,3-glucanases were detected in induced chickpea plants. The molecular mass of the purified chitinases was 31 and 62 kDa and β-1,3-glucanases was 23, 27 and 39 kDa. Purified chitinases and β-1,3-glucanases also inhibited growth of Fusarium oxysporum f. sp. ciceri and other phytopathogenic fungi.

Chitinolytic enzymes from endophytic fungi

Abstract: Fungal endophytes isolated from leaves of tree species of the forests of Western Ghats, southern India were screened for chitin modifying enzyme production. Thirty-one of the one hundred and sixty two isolates were positive for chitinase, while different isolates produced isoforms of the enzyme. Many isolates produced chitosanase that acted on chitosan with different degrees of acetylation. Modified chitin and different types of chitosans are used in biomedical applications including wound healing, drug delivery, gene delivery, tissue engineering, in the food industry as preservatives and emulsifying agents, and in biocatalysis. Horizontally transmitted endophytes appear to be a good source for a variety of chitin modifying enzymes with the potential to be used in biotechnology. The possibility of chitin modifying enzymes of endophytes in regulating plant defense against pathogens and pests in vivo should also be addressed.

Regulation, expression and function of a new basic chitinase gene in rice (Oryza sativa L.)

Abstract: A new basic chitinase gene, designated RC24, was isolated from a rice genomic library. The predicted RC24 protein contains 322 amino acid residues and exhibits 68% to 95% amino acid identity with known class I rice chitinases. RC24 protein expressed in Escherichia coli exhibited chitinase activity and strongly inhibited bacterial growth. Two transcription start sites of the RC24 gene were mapped by primer extension analysis of both rice native RNA and in vitro transcribed RNA using a RC24 promoter/GUS (β-glucuronidase) gene fusion as a template. The 5′-franking region of RC24 contained several putative stress-responsive cis-acting elements. A basal level of RC24 transcripts was detected in rice root and stem tissues, but not in leaf tissues. RC24 transcripts rapidly accumulated within 1 h after fungal elicitor treatment of suspension-cultured cells, and the levels continued to increase for at least 9 h. RC24 transcript accumulation was also observed in intact leaf tissues upon wounding. Transgenic rice plants containing the RC24/GUS gene fusion further confirmed that the RC24 gene showed a tissue-specific expression pattern and that transcription of the RC24 promoter was sensitively and rapidly activated by wounding.