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: In this paper, the chitin nanocrystal surface coating significantly impacted the surface properties of the membranes, producing a super-hydrophilic membrane (contact angle 0°) from the original hydrophobic CA mats.
176 citations
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TL;DR: Using a novel screen, it is identified three mutations, designated csd2, csd3, and csd4, that reduce levels of chitin in vivo by as much as 10-fold without causing any obvious perturbation of cell division.
Abstract: In Saccharomyces cerevisiae, chitin forms the primary division septum and the bud scar in the walls of vegetative cells. Three chitin synthetic activities have been detected. Two of them, chitin synthase I and chitin synthase II, are not required for synthesis of most of the chitin present in vivo. Using a novel screen, I have identified three mutations, designated csd2, csd3, and csd4, that reduce levels of chitin in vivo by as much as 10-fold without causing any obvious perturbation of cell division. The csd2 and csd4 mutants lack chitin synthase III activity in vitro, while csd3 mutants have wild-type levels of this enzyme. In certain genetic backgrounds, these mutations cause temperature-sensitive growth on rich medium; inclusion of salts or sorbitol bypasses this phenotype. Gene disruption experiments show that CSD2 is nonessential; a small amount of chitin, about 5% of the wild-type level, is detected in the disruptants. DNA sequencing indicates that the CSD2 protein has limited, but statistically significant, similarity to chitin synthase I and chitin synthase II. Other significant similarities are to two developmental proteins: the nodC protein from Rhizobium species and the DG42 protein of Xenopus laevis. The relationship between the nodC and CSD2 proteins suggests that nodC may encode an N-acetylglucosaminyltransferase that synthesizes the oligosaccharide backbone of the nodulation factor NodRm-1.
176 citations
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TL;DR: Phylogenetic analysis showed that bacterial family 18 chitinases can be clustered in three subfamilies which have diverged at an early stage of bacterial chit inase evolution.
Abstract: The third chitinase gene (chiC) of Serratia marcescens 2170, specifying chitinases C1 and C2, was identified. Chitinase C1 lacks a signal sequence and consists of a catalytic domain belonging to glycoside hydrolase family 18, a fibronectin type III-like domain (Fn3 domain) and a C-terminal chitin-binding domain (ChBD). Chitinase C2 corresponds to the catalytic domain of C1 and is probably generated by proteolytic removal of the Fn3 and ChBDs. The loss of the C-terminal portion reduced the hydrolytic activity towards powdered chitin and regenerated chitin, but not towards colloidal chitin and glycol chitin, illustrating the importance of the ChBD for the efficient hydrolysis of crystalline chitin. Phylogenetic analysis showed that bacterial family 18 chitinases can be clustered in three subfamilies which have diverged at an early stage of bacterial chitinase evolution. Ser. marcescens chitinase C1 is found in one subfamily, whereas chitinases A and B of the same bacterium belong to another subfamily. Chitinase C1 is the only Ser. marcescens chitinase that has an Fn3 domain. The presence of multiple, divergent, chitinases in a single chitinolytic bacterium is perhaps necessary for efficient synergistic degradation of chitin.
176 citations
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TL;DR: D dye/chitosan interaction showed favorable enthalpic and entropic processes, reflecting thermodynamic stability of the formed complex, while dye/ chitin interaction showed an exothermicEnthalpic value and a highly nonfavorable entropics effect, resulting in a nonspontaneous thermodynamic system.
176 citations
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TL;DR: The results indicate that the chitosan heptamer-plus fraction readily recovered from these plant-fungal interactions is able to function as a major biological signal in pea/-Fusarium interactions while the ch itosan pentamer which preferentially accumulates in f.
175 citations