scispace - formally typeset
Search or ask a question
Topic

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.


Papers
More filters
Journal ArticleDOI
TL;DR: Results indicate that the chitin-binding domain helps determine the movement of chit inase along N-acetylglucosamine strands and within environments containing chitIn.
Abstract: To examine the ecology and evolution of microbial chitinases, especially the chitin-binding domain, one of the chitinase genes (chiA) from the marine bacterium Vibrio harveyi was analysed. The deduced amino acid sequence of ChiA is not very similar overall to other proteins, except for two regions, the putative catalytic and chitin-binding domains. Among all bacterial chitinases sequenced to date, there is no relationship between percentage similarity of catalytic domains and chitin-binding domains in pairwise comparisons, suggesting that these two domains have evolved separately. The chitin-binding domain appears to be evolutionarily conserved among many bacterial chitinases and is also somewhat similar to cellulose-binding domains found in microbial cellulases and xylanases. To investigate the role of the chitin-binding domain, clones producing versions of ChiA with or without this domain were examined. One version with the domain (ChiA1) bound to and hydrolysed chitin, whereas a truncated ChiA without the putative chitin-binding domain (ChiA2) did not bind to chitin but it could hydrolyse chitin, although not as well. ChiA1 diffused more slowly in agarose containing colloidal chitin than ChiA2, but diffusion of the Two proteins in agarose without colloidal chitin was similar. These results indicate that the chitin-binding domain helps determine the movement of chitinase along N-acetylglucosamine strands and within environments containing chitin.

103 citations

Journal ArticleDOI
TL;DR: The high levels of chitinase activity in habitual smokers result from upregulation of CHIT1 gene expression, especially in macrophages, which is not increased in subjects with asthma and in fact tends to be decreased.
Abstract: Background Chitinolytic enzymes play important roles in the pathophysiology of allergic airway responses in mouse models of asthma. Acidic mammalian chitinase (AMCase) and chitotriosidase (CHIT1) have chitinolytic activity, but relatively little is known about their expression in human asthma. Objective We sought to determine the expression and activity of AMCase and CHIT1 in healthy subjects, subjects with asthma, and habitual smokers, taking account of the null 24-bp duplication in the CHIT1 gene. Methods We measured chitinase activity in bronchoalveolar lavage (BAL) fluid at multiple pHs by using a synthetic chitin substrate. We also determined AMCase and CHIT1 gene expression in epithelial brushings and BAL fluid macrophages by means of real time RT-PCR. Paired DNA samples were genotyped for the CHIT1 duplication. Results In all subgroups the pH profile of chitinase activity in BAL fluid matched that of CHIT1, but not AMCase, and chitinase activity was absent in subjects genetically deficient in active CHIT1. Although AMCase protein was detectable in lavage fluid, AMCase transcripts in macrophages were consistent with an isoform lacking enzymatic activity. Median chitinase activity in BAL fluid tended to be lower than normal in asthmatic subjects but was increased 7-fold in habitual smokers, where CHIT1 gene expression in macrophages was increased. Conclusions Chitinase activity in the lung is the result of CHIT1 activity. Although AMCase protein is detectable in the lung, our data indicate that it is inactive. Chitinase activity is not increased in subjects with asthma and in fact tends to be decreased. The high levels of chitinase activity in habitual smokers result from upregulation of CHIT1 gene expression, especially in macrophages.

103 citations

Journal ArticleDOI
TL;DR: Clone libraries of chitinase gene fragments amplified from coastal Pacific Ocean and estuarine Delaware Bay bacterioplankton revealed similarities and differences between cultured and uncultured bacteria, suggesting that a closer examination of Chitin degradation by α-proteobacteria will lead to a better understanding of ch itin degradation in the ocean.
Abstract: PCR primers were patterned after chitinase genes in four γ-proteobacteria in the families Alteromonadaceae and Enterobacteriaceae (group I chitinases) and used to explore the occurrence and diversity of these chitinase genes in cultured and uncultured marine bacteria. The PCR results from 104 bacterial strains indicated that this type of chitinase gene occurs in two major groups of marine bacteria, α- and γ-proteobacteria, but not the Cytophaga-Flavobacter group. Group I chitinase genes also occur in some viruses infecting arthropods. Phylogenetic analysis indicated that similar group I chitinase genes occur in taxonomically related bacteria. However, the overall phylogeny of chitinase genes did not correspond to the phylogeny of 16S rRNA genes, possibly due to lateral transfer of chitinase genes between groups of bacteria, but other mechanisms, such as gene duplication, cannot be ruled out. Clone libraries of chitinase gene fragments amplified from coastal Pacific Ocean and estuarine Delaware Bay bacterioplankton revealed similarities and differences between cultured and uncultured bacteria. We had hypothesized that cultured and uncultured chitin-degrading bacteria would be very different, but in fact, clones having nucleotide sequences identical to those of chitinase genes of cultured α-proteobacteria dominated both libraries. The other clones were similar but not identical to genes in cultured γ-proteobacteria, including vibrios and alteromonads. Our results suggest that a closer examination of chitin degradation by α-proteobacteria will lead to a better understanding of chitin degradation in the ocean.

102 citations

Journal ArticleDOI
TL;DR: Results from the present study demonstrated the significant potential of the purified compound from isolate C9 for use as a biocontrol agent as well as a plant growth promoter with the ability to trigger induced systemic resistance of plants.
Abstract: Antagonistic microorganisms against Rhizoctonia solani were isolated and their antifungal activities were investigated. Two hundred sixteen bacterial isolates were isolated from various soil samples and 19 isolates were found to antagonize the selected plant pathogenic fungi with varying degrees. Among them, isolate C9 was selected as an antagonistic microorganism with potential for use in further studies. Treatment with the selected isolate C9 resulted in significantly reduced incidence of stem-segment colonization by R. solani AG2-2(IV) in Zoysia grass and enhanced growth of grass. Through its biochemical, physiological, and 16S rDNA characteristics, the selected bacterium was identified as Bacillus subtilis subsp. subtilis. Mannitol (1%) and soytone (1%) were found to be the best carbon and nitrogen sources, respectively, for use in antibiotic production. An antibiotic compound, designated as DG4, was separated and purified from ethyl acetate extract of the culture broth of isolate C9. On the basis of spectral data, including proton nuclear magneric resonance (1H NMR), carbon nuclear magneric resonance (13C NMR), and mass analyses, its chemical structure was established as a stereoisomer of acetylbutanediol. Application of the ethyl acetate extract of isolate C9 to several plant pathogens resulted in dose-dependent inhibition. Treatment with the purified compound (an isomer of acetylbuanediol) resulted in significantly inhibited growth of tested pathogens. The cell free culture supernatant of isolate C9 showed a chitinase effect on chitin medium. Results from the present study demonstrated the significant potential of the purified compound from isolate C9 for use as a biocontrol agent as well as a plant growth promoter with the ability to trigger induced systemic resistance of plants.

102 citations

Journal ArticleDOI
TL;DR: The results demonstrate that these two enzymes have antifungal activity against U. necator, and are consistent with these pathogenesis‐related proteins having a role in defence of grapevines against powdery mildew.
Abstract: Leaves were collected from 21 different grapevine (Vitis ssp.) genotypes with varying resistance to powdery mildew disease caused by Uncinula necator. For leaves collected from field‐grown vines in spring there was a correlation between resistance rating and activity of chitinase and β‐1,3‐glucanase. The correlation was greater with the sum of the two enzyme activities. In contrast, no correlation was obtained for leaves collected during summer. With leaves from glasshouse grown vines, wounding or infection with powdery mildew increased both chitinase and β‐1,3‐glucanase activity. Light microscope examination of detached leaves inoculated with U. necator conidia showed that germination appeared to occur at the same rate on leaves of a susceptible (Sultana) and a resistant (Seyval) genotype. Subsequent development of mycelia was severely restricted on the resistant genotype but it was prolific on the sensitive genotype. A bioassay was developed based on germination and extension of the germ tube of U. necator conidia on agar plates. Agar preparations containing desalted crude extracts of grapevine leaves inhibited growth and caused the tips of the hyphae to rupture. The effect was not observed with boiled extracts and was greater with extracts from resistant genotypes. Chitinase and β‐1,3‐glucanase were purified 760‐fold and 46‐fold respectively from leaves of Seyval grapevines. The purified enzyme preparations inhibited germ tube growth, with the effect being more prominent in the presence of both enzymes. The results demonstrate that these two enzymes have antifungal activity against U. necator, and are consistent with these pathogenesis‐related proteins having a role in defence of grapevines against powdery mildew.

102 citations


Network Information
Related Topics (5)
Enzyme
32.8K papers, 1.1M citations
85% related
Protease
28.9K papers, 945.8K citations
84% related
Germination
51.9K papers, 877.9K citations
84% related
Gel electrophoresis
26K papers, 1.1M citations
83% related
cDNA library
17.3K papers, 930.2K citations
83% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023186
2022337
2021148
2020172
2019154
2018152