Topic
Chitin
About: Chitin is a research topic. Over the lifetime, 6590 publications have been published within this topic receiving 253993 citations.
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TL;DR: The preparation, physicochemical properties, chemical and physical modification methods of chitosan, which could help to understand its biological activities and applications, and some insights into its future potential are provided.
188 citations
TL;DR: Shiitake and crab chitosan were strong antimicrobial agents and moderate antitumor agents and showed slightly better antimicrobial and antitumors activities than crab ch itosan.
188 citations
TL;DR: The mechanism of in vivo synthesis of chitin has been clarified by cloning the structural gene for the newly found chitIn synthase 2, a relatively minor activity in yeast, establishing that the gene product is essential for both septum formation and cell division.
Abstract: Previous work led to the puzzling conclusion that chitin synthase 1, the major chitin synthase activity in Saccharomyces cerevisiae, is not required for synthesis of the chitinous primary septum. The mechanism of in vivo synthesis of chitin has now been clarified by cloning the structural gene for the newly found chitin synthase 2, a relatively minor activity in yeast. Disruption of the chitin synthase 2 gene results in the loss of well-defined septa and in growth arrest, establishing that the gene product is essential for both septum formation and cell division.
187 citations
TL;DR: Chitin synthesis was studied in both yeast and hyphae of the dimorphic fungus Candida albicans, and enzyme activity was found to be located on the inner side of the plasma membrane.
Abstract: Chitin synthesis was studied in both yeast and hyphae of the dimorphic fungus Candida albicans. Incorporation of N-acetyl-d-[1-(3)H]glucosamine ([(3)H]GluNAc) into an acid-alkali-insoluble fraction was 10 times greater in hyphal-phase cells. A crude preparation of chitin synthetase was obtained from sonically treated protoplasts of both forms of Candida. Enzyme activity, which was determined by using [(14)C]UDP-GLuNAc as a substrate, was exclusively associated with the 80,000 x g pellet from sonically treated protoplasts of both forms. It was determined that enzyme activity (nanomoles of [(14)C]UDP-GluNAc incorporated per milligram of protein) was approximately 2 times greater in hyphae versus yeast cells. Enzyme activity in both yeast and hyphae increased six- to sevenfold when the enzyme preparations were preincubated with trypsin. A vacuolar fraction, obtained from yeast cells but not from hyphae, stimulated enzyme activity when incubated with either yeast or hyphal enzyme preparations. Membrane fractions from protoplasts coated with [(3)H]concanavalin A before disruption were isolated by Renografin density gradient centrifugation. Chitin synthetase activity was preferentially associated with the concanavalin A-labeled fraction, suggesting that the enzyme was located on the plasma membrane. In addition, enzyme activity in protoplasts treated with cold glutaraldehyde before disruption was significantly greater than in protoplasts that were sonically disrupted and then treated with cold glutaraldehyde, indicating that the enzyme resides on the inner side of the plasma membrane.
187 citations
187 citations