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 expression of chitinase in combination with one or several different antifungal proteins should have a greater effect on reducing disease development, given the complexities of fungal-plant cell interactions and resistance responses in plants.
Abstract: Chitinases are enzymes that hydrolyze the N-acetylglucosamine polymer chitin, and they occur in diverse plant tissues over a broad range of crop and noncrop species. The enzymes may be expressed constitutively at low levels but are dramatically enhanced by numerous abiotic agents (ethylene, salicylic acid, salt solutions, ozone, UV light) and by biotic factors (fungi, bacteria, viruses, viroids, fungal cell wall components, and oligosaccharides). Different classes of plant chitinases are distinguishable by molecular, biochemical, and physicochemical criteria. Thus, plant chitinases may differ in substrate-binding characteristics, localization within the cell, and specific activities. Because chitin is a structural component of the cell wall of many phytopathogenic fungi, extensive research has been conducted to determine whether plant chitinases have a role in defense against fungal diseases. Plant chitinases have different degrees of antifungal activity to several fungi in vitro. In vivo, although rapid accumulation and high levels of chitinases (together with numerous other pathogenesis-related proteins) occur in resistant tissues expressing a hypersensitive reaction, high levels also can occur in susceptible tissues. Expression of cloned chitinase genes in transgenic plants has provided further evidence for their role in plant defense. The level of protection observed in these plants is variable and may be influenced by the specific activity of the enzyme, its localization and concentration within the cell, the characteristics of the fungal pathogen, and the nature of the host-pathogen interaction. The expression of chitinase in combination with one or several different antifungal proteins should have a greater effect on reducing disease development, given the complexities of fungal-plant cell interactions and resistance responses in plants. The effects of plant chitinases on nematode development in vitro and in vivo are worthy of investigation.
244 citations
TL;DR: In this paper, the degree of substitution (DS) is an important parameter when assessing the conversion of chitin into one of its derivates, and FT-IR spectroscopy is a relatively easy but indirect way of determining the DS.
244 citations
TL;DR: The catalytic mechanisms of these enzymes as well as the structural basis of each enzyme's specific role in the chitin degradation process are discussed, and how knowledge of this enzyme system may be extrapolated to other enzyme systems for conversion of insoluble polysaccharides is discussed.
Abstract: The chitinolytic machinery of Serratia marcescens is one of the best known enzyme systems for the conversion of insoluble polysaccharides This machinery includes four chitin-active enzymes: ChiC, an endo-acting non-processive chitinase; ChiA and ChiB, two processive chitinases moving along chitin chains in opposite directions; and CBP21, a surface-active CBM33-type lytic polysaccharide monooxygenase that introduces chain breaks by oxidative cleavage Furthermore, an N-acetylhexosaminidase or chitobiase converts the oligomeric products from the other enzymes to monomeric N-acetylglucosamine Here we discuss the catalytic mechanisms of these enzymes as well as the structural basis of each enzyme's specific role in the chitin degradation process We also discuss how knowledge of this enzyme system may be extrapolated to other enzyme systems for conversion of insoluble polysaccharides, in particular conversion of cellulose by cellulases and GH61-type lytic polysaccharide monooxygenases
243 citations
TL;DR: Common principles and differences will be worked out at the levels of gene organization, enzymatic properties, cellular localization and regulation in chitin synthesis.
242 citations
TL;DR: It is concluded that although a dual mode of action was involved in the control of gray mould by chitosan, the antifungal activity of the compound was an essential factor to suppress the disease.
242 citations