The properties and behavior of a “microsomal” (100,000 X g particles) chitin synthetase of Mucor rouxii were investigated. The enzyme utilizes uridine diphosphate N-acetylD-glucosamine (UDP-GlcNAc) as glycosyl donor and is strongly and specifically activated by free N-acetyl-o-glucosamine (GlcNAc). A variety of GlcNAc analogues were tested as activators but were found ineffective. A small propo...

Levels of the anaphylatoxin C3a are increased in patients with asthma compared with those in nonasthmatics and increase further still during asthma exacerbations. However, the role of C3a during sensitization to allergen is poorly understood. Sensitization to fungal allergens, such as Aspergillus fumigatus, is a strong risk factor for the development of asthma. Exposure to chitin, a structural ...

The distribution of chitin in Saccharomyces cervisiae primary septa and cell walls was studied with three methods: electron microscopy of colloidal gold particles coated either with wheat germ agglutinin or with one of two different chitinases, fluorescence microscopy with fluorescein isothiocyanate derivatives of the same markers, and enzymatic treatments of [14C]glucosamine-labeled cells. The...

Chitinases are hydrolases that degrade chitin, a polymer of N-acetylglucosamine linked β(1-4) present in the exoskeleton of crustaceans, insects, nematodes and fungal cell walls. A metagenome fosmid library from a wastewater-contaminated soil was functionally screened for chitinase activity leading to the isolation and identification of a chitinase gene named metachi18A. The metachi18A gene was...

Background: Chitin is an important natural resource. The annual worldwide production is estimated in approximately 10 10 -10 12 ton. It is produced by arthropods (insects and crustaceans), molluscs and fungi. Its main biological function is structural. Crustacean shells are the most important chitin source for commercial use due to its high content and ready availability. Chitin and its derivat...

In Saccharomyces cerevisiae most chitin is synthesized by Chs3p, which deposits chitin in the lateral cell wall and in the bud-neck region during cell division. We have recently found that addition of glucosamine (GlcN) to the growth medium leads to a three- to fourfold increase in cell wall chitin levels. We compared this result to the increases in cellular chitin levels associated with cell w...

The marine bacterium Microbulbifer degradans strain 2-40 produces at least 10 enzyme systems for degrading insoluble complex polysaccharides (ICP). The draft sequence of the 2-40 genome allowed a genome-wide analysis of the chitinolytic system of strain 2-40. The chitinolytic system includes three secreted chitin depolymerases (ChiA, ChiB, and ChiC), a secreted chitin-binding protein (CbpA), pe...

The purpose of this study was to investigate chitin and chitosan as potential materials for biodegradable nerve guides. Transparent chitin hydrogel tubes were synthesized, for the first time, from chitosan solutions using acylation chemistry and mold casting techniques. Alkaline hydrolysis of chitin tubes resulted in chitosan tubes, with the extent of hydrolysis controlling the resulting amine ...

Treatment of Aspergillus fumigatus with echinocandins such as caspofungin inhibits the synthesis of cell wall β-1,3-glucan, which triggers a compensatory stimulation of chitin synthesis. Activation of chitin synthesis can occur in response to sub-MICs of caspofungin and to CaCl2 and calcofluor white (CFW), agonists of the protein kinase C (PKC), and Ca(2+)-calcineurin signaling pathways. A. fum...