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Showing papers on "Chitinase published in 2002"


Journal ArticleDOI
TL;DR: Surface modification of the fungal cell walls by chitin de- N -acetylation is discussed as a fungal strategy to protect cell walls of pathogenic hyphae from enzymatic hydrolysis by host chit inases, and to avoid generation of an auto-catalytic defense response system in the invaded host tissue.
Abstract: Summary • Conversion of surface-exposed chitin to chitosan in cell walls of in vitro - and in vivo -differentiated infection structures of two rust fungi, the wheat stem rust fungus Puccinia graminis f. sp. tritici and the broad bean rust fungus Uromyces fabae , and of the causal agent of maize anthracnose, Colletotrichum graminicola , were studied. • Epi-fluorescence microscopy with the fluorescence-labeled lectin wheat germ agglutinin (WGA) revealed that surfaces of infection structures formed on the plant cuticle expose chitin, whereas surfaces of structures formed after invading the host do not. • To identify chitin modification by de- N -acetylation, we raised polyclonal antibodies specifically recognizing de- N -acetylated chitosan. These antibodies labeled only those infection structures that differentiate inside the plant, indicating that chitosan is exposed on cell wall surfaces post penetration. • Surface modification of the fungal cell walls by chitin de- N -acetylation is discussed as a fungal strategy to protect cell walls of pathogenic hyphae from enzymatic hydrolysis by host chitinases, and to avoid generation of an auto-catalytic defense response system in the invaded host tissue.

227 citations


Journal ArticleDOI
TL;DR: A chitin‐degrading Bacillus strain, designated as NCTU2, was screened from soil and an extracellular chitInase was purified to >90% homogeneity from the culture filtrate, indicating that the purified chit inase is an exo‐chitinase.
Abstract: A chitin-degrading Bacillus strain, designated as NCTU2, was screened from soil and identified. An extracellular chitinase was purified to >90% homogeneity from the culture filtrate. The purification involved hydrophobic-interaction and gel-filtration chromatographic separations with a yield of 58%. The purified enzyme (ChiNCTU2) is a monomeric protein with an estimated molecular mass of 36.5 kDa and a pI of 6.3. It is thermally stable at 60 degrees C and pH 6-8 for more than 3 h. The optimal activity is in the range of 50-60 degrees C at pH 7.0. Chitobiose is the predominant product throughout the enzymic hydrolysis of the colloidal chitin, indicating that the purified chitinase is an exo-chitinase. Chito-oligosaccharides [with degree of polymerization (DP) values of 4-6] are good substrates of the purified enzyme, whereas a DP3 oligomer was slowly hydrolysed to form DP1 and DP2 sugars. The first 15 N-terminal amino acids of the enzyme were determined to be ANNLGSKLLVGYWHN, which is highly homologous to that of ChiA from Bacillus cereus. A PCR cloning technique was employed to obtain the corresponding gene from Bacillus NCTU2. The gene sequence was determined to be 1080 bp, encoding a polypeptide of 360 amino acids with the first 27 amino acids as the signal peptide.

212 citations


Journal ArticleDOI
TL;DR: The crystal structure of the human chitotriosidase and complexes with a chitooligosaccharide and allosamidin reveal an elongated active site cleft, compatible with the binding of long chitin polymers, and explain the inactivation of the enzyme through an inherited genetic deficiency.

199 citations


Journal ArticleDOI
TL;DR: B. mycoides isolate Bac J, a non-pathogenic, phyllosphere-inhabiting bacterium, reduces Cercospora leaf spot ( CercOSpora beticola Sacc.) of sugar beet by 38–91% in both glasshouse and field experiments.

194 citations


Journal ArticleDOI
TL;DR: In this article, the individual roles of the chitinases from Serratia marcescens 2170 were studied and a broad pH optimum was found for chitinolytic activity between pH 4 and 10, and the sites attacked by ChiA on the substrate were different from those by either ChiB or ChiC1.
Abstract: To discover the individual roles of the chitinases from Serratia marcescens 2170, chitinases A, B, and C1 (ChiA, ChiB, and ChiC1) were produced by Escherichia coli and their enzymatic properties as well as synergistic effect on chitin degradation were studied. All three chitinases showed a broad pH optimum and maintained significant chitinolytic activity between pH 4 and 10. ChiA was the most active enzyme toward insoluble chitins, but ChiC1 was the most active toward soluble chitin derivatives among the three chitinases. Although all three chitinases released (GlcNAc)2 almost exclusively from colloidal chitin, ChiB and ChiC1 split (GlcNAc)6 to (GlcNAc)3, while ChiA exclusively generated (GlcNAc)2 and (GlcNAc)4. Clear synergism on the hydrolysis of powdered chitin was observed in the combination between ChiA and either ChiB or ChiC, and the sites attacked by ChiA on the substrate are suggested to be different from those by either ChiB or ChiC1.

175 citations


Journal ArticleDOI
TL;DR: Pairwise comparisons of each domain to the most closely related sequences found in database searches clearly demonstrated variation in gene sources and the species from which related sequences originated.
Abstract: A chitinase gene was cloned on a 2.8-kb DNA fragment from Stenotrophomonas maltophilia strain 34S1 by heterologous expression in Burkholderia cepacia. Sequence analysis of this fragment identified an open reading frame encoding a deduced protein of 700 amino acids. Removal of the signal peptide sequence resulted in a predicted protein that was 68 kDa in size. Analysis of the sequence indicated that the chitinase contained a catalytic domain belonging to family 18 of glycosyl hydrolases. Three putative binding domains, a chitin binding domain, a novel polycystic kidney disease (PKD) domain, and a fibronectin type III domain, were also identified within the sequence. Pairwise comparisons of each domain to the most closely related sequences found in database searches clearly demonstrated variation in gene sources and the species from which related sequences originated. A 51-kDa protein with chitinolytic activity was purified from culture filtrates of S. maltophilia strain 34S1 by hydrophobic interaction chromatography. Although the protein was significantly smaller than the size predicted from the sequence, the N-terminal sequence verified that the first 15 amino acids were identical to the deduced sequence of the mature protein encoded by chiA. Marker exchange mutagenesis of chiA resulted in mutant strain C5, which was devoid of chitinolytic activity and lacked the 51-kDa protein in culture filtrates. Strain C5 was also reduced in the ability to suppress summer patch disease on Kentucky bluegrass, supporting a role for the enzyme in the biocontrol activity of S. maltophilia.

159 citations


Journal ArticleDOI
TL;DR: The results show that rat bacterial enzymes had the ability to degrade chitosan with extracellular enzymes exhibiting a more profound effect than did cell-associated enzymes, which indicates that almond emulsin beta-glucosidase might be able to be used as an in vitro enzyme system to predict the large intestinal degradation of chitOSan.

140 citations


Journal ArticleDOI
TL;DR: This is the first report of the isolation of chitinases from B. amyloliquefaciens that are active against fungi, and the unique characteristics of V656 chit inases include extremely low molecular weights and nearly neutral optimum pH.
Abstract: A Gram-positive bacterium with antagonistic activity was isolated from the soil. It has been identified as Bacillus amyloliquefaciens strain V656 on the basis of 16S ribosomal DNA analysis and standard bacteriological tests. B. amyloliquefaciens V656 produced antifungal enzymes when it was grown in a medium containing shrimp and crab shell powder (SCSP) of marine waste. The antifungal enzymes displayed chitinase activities. Two extracellular antifungal chitinases (FI and FII) were purified and characterized, and their molecular weights, isoelectric points, pH and thermal stabilities, and antifungal activities were determined. The characteristics of V656 chitinases are similar to those of the known bacterial chitinases in terms of their isoelectric points, thermal instabilities, and lack of lysozyme activity. In contrast to other known bacterial chitinases, the unique characteristics of V656 chitinases include extremely low molecular weights and nearly neutral optimum pH. Furthermore, this is the first report of the isolation of chitinases from B. amyloliquefaciens that are active against fungi.

135 citations


Journal ArticleDOI
TL;DR: The characterization of a diverse set of chitinase and glucanase genes from T. virens suggest interdependent regulation of this important gene family in this widely distributed soil fungus.
Abstract: Trichoderma virens is a widely distributed soil fungus that is parasitic on other soil fungi. The mycoparasitic activity of T. virens is correlated with the production of numerous antifungal activities, including the secretion of a considerable repertoire of fungal cell wall-degrading enzymes. Here, we report the characterization of a diverse set of chitinase and glucanase genes from T. virens. In each case, full-length genomic clones were isolated and characterized, while sequencing of the corresponding cDNA clones and manual annotation provided a basis for establishing gene structure. Based on homology of the deduced amino acid sequences, we have identified three members of the 42Kd endochitinase gene family, two 33Kd exochitinases, two exochitinases with homology to N-acetylglucosaminidases, and three glucanase genes predicted to encode β-1,3- and β-1,6-proteins. The majority of these genes appear to encode signal peptides, suggesting an extracellular location for the corresponding proteins. Despite their overall similarity, the 42Kd class of chitinases can be subdivided, based on the presence of distinct N-terminal domains, suggesting that the proteins may have distinct cellular roles, while Northern blot analysis confirms that these genes possess distinct patterns of gene regulation. Similarly, one of the 33Kd chitinase genes is unique, because it is predicted to encode a protein C-terminus with high homology to the conserved family I cellulose-binding domain. The expression patterns of the chitinase genes were analyzed in both a wild-type strain and a strain disrupted for the major 42Kd chitinase gene of T. virens. The results of these transcript analyses, together with enzymatic assay of the extracellular proteins, suggest interdependent regulation of this important gene family in T. virens.

127 citations


Journal ArticleDOI
TL;DR: Results show that multiple chitinase homologs are induced after challenge by a necrotrophic pathogen and by potential signaling molecules identified in angiosperms, suggesting the potential importance of de novo pathogenesis-related (PR) gene expression in pathogen defense responses of pine trees.
Abstract: To better understand the molecular regulation of defense responses in members of the genus Pinus, we tested the expression of various chitinase homologs in response to pathogen-associated signals. PSCHI4, a putative extracellular class II chitinase, was secreted into liquid medium by pine cells and was also secreted by transgenic tobacco cells that ectopically expressed pschi4. Extracellular proteins of pine were separated by isoelectric focusing; PSCHI4 was not associated with fractions containing detectable β-N-acetylglucosaminidase or lysozyme activities. However, other fractions contained enzyme activities that increased markedly after elicitor treatment. The pschi4 transcript and protein accumulated in pine seedlings challenged with the necrotrophic pathogen Fusarium subglutinans f. sp. pini, with the protein reaching detectable levels in susceptible seedlings concomitant with the onset of visible disease symptoms. Additional chitinase transcripts, assigned to classes I and IV based on primary sequen...

117 citations


Journal ArticleDOI
TL;DR: Aim: Purification and characterization of a chitinase from Microbispora sp.
Abstract: Aim: Purification and characterization of a chitinase from Microbispora sp. V2. Methods and Results: The chitinase from Microbispora sp. V2 was purified to homogeneity by gel filtration chromatography with 4·6% recovery. It had a molecular weight of 35 kDa and showed maximum activity towards p-nitrophenyl-β-d-N,N′-diacetylchitobiose, indicating a chitobiosidase activity. The enzyme had a pH optimum of 3·0 and temperature optimum of 60 °C. It was stable in a wide pH range from 3·0 to 11·0, retaining 61% activity at pH 3·0 and 52% activity at pH 11·0. It retained 71% activity at 30 °C and 45% activity at 50 °C, up to 24 h. The enzyme activity was not inhibited by any of the metal ions tested except Hg2+, in the presence of which only 10% activity was retained. Conclusions: The 35 kDa chitinase from Microbispora sp. V2 has an acidic pH optimum and a high temperature optimum. It is fairly stable and active, and degrades chitin efficiently, although the growth of the culture and enzyme production is slow. Significance and Impact of the Study: This report is the first detailed study of a chitinase from Microbispora sp. V2, isolated from hot springs. The chitinase from Microbispora sp. V2 may have potential applications in the recycling of chitinous wastes, particularly due to its thermophilic and acidophilic character. Studies at molecular level may provide further insight on the chitinolytic system of Microbispora spp. with respect to the number and types of chitinases and their regulation.

Journal Article
TL;DR: A soil bacterium, Bacillus sp.
Abstract: A soil bacterium, Bacillus sp. strain BC121, isolated from the rhizosphere of sorghum, showed high antagonistic activity against Curvularia lunata. A clear inhibition zone of 0.5-1 cm was observed in dual plate assay. After 10 days of incubation, the bacterial strain grew over the fungal mycelial surface and multiplied extensively on it. Scanning electron microscopic observations showed a clear hyphal lysis and degradation of fungal cell wall. In dual cultures, the Bacillus strain BC121 inhibited the C. lunata up to 60% in terms of dry weight. This strain also produced a clear halo region on chitin agar medium plates containing 0.5% colloidal chitin, indicating that it excretes chitinase. The role of the Bacillus strain BC121 in suppressing the fungal growth in vitro was studied in comparison with a mutant of that strain, which lacks both antagonistic activity and chitinolytic activity. The extra-cellular protein precipitate from Bacillus strain BC121 culture filtrate had significant growth-retarding effect and mycolytic activity on C. lunata. The protein extract from the wild strain, when tested on SDS-PAGE gel showed a unique band corresponding to the molecular mass of 25 kDa, which could be the probable chitinase protein.

Journal ArticleDOI
TL;DR: High-resolution crystal structures are described that reveal the details of the interactions of these cyclopeptides with a family 18 chitinase and provide a basis for structure-based design of potent chit inase inhibitors, accessible by standard peptide chemistry.
Abstract: Over the past years, family 18 chitinases have been validated as potential targets for the design of drugs against human pathogens that contain or interact with chitin during their normal life cycles. Thus far, only one potent chitinase inhibitor has been described in detail, the pseudotrisaccharide allosamidin. Recently, however, two potent natural-product cyclopentapeptide chitinase inhibitors, argifin and argadin, were reported. Here, we describe high-resolution crystal structures that reveal the details of the interactions of these cyclopeptides with a family 18 chitinase. The structures are examples of complexes of a carbohydrate-processing enzyme with high-affinity peptide-based inhibitors and show in detail how the peptide backbone and side chains mimic the interactions of the enzyme with chitooligosaccharides. Together with enzymological characterization, the structures explain why argadin shows an order of magnitude stronger inhibition than allosamidin, whereas argifin shows weaker inhibition. The peptides bind to the chitinase in remarkably different ways, which may explain the differences in inhibition constants. The two complexes provide a basis for structure-based design of potent chitinase inhibitors, accessible by standard peptide chemistry.

Journal ArticleDOI
TL;DR: The data indicate that, in V. vinifera, induction of chitinase genes depends on the infecting pathogen, and accumulation of class III transcripts was observed in response to P. syringae but not to B. cinerea infection.

Journal ArticleDOI
TL;DR: It was demonstrated that chitinase was widely produced in B. thuringiensis strains and some of the strains could enhance the toxicity of active B.Thuringienis strain against Spodoptera exigua larvae, and the bioassay results indicated that the chit inase‐producing B. Thuringiens is might play a role in the activity of the biopesticide.
Abstract: M . L I U , Q . X . C A I , H . Z . L I U , B . H . Z H A N G , J . P . Y A N A N D Z . M . Y U A N . 2002. Aims: To investigate the distribution of chitinase in Bacillus thuringiensis strains, and the enhancing effects of the chitinase-producing B. thuringiensis strains on insecticidal toxicity of active B. thuringiensis strain against Spodoptera exigua larvae. Methods and Results: The chitinolytic activities of B.thuringiensis strains representing the 70 serotypes were investigated by the whitish opaque halo and the colorimetric method. Thirtyeight strains produced different levels of chitinase at pH 7AE0, and so did 17 strains at pH 10AE0. The strain T04A001 exhibited the highest production, reaching a specific activity of 355 U ml )1 in liquid medium. SDS-PAGE and Western blotting showed that the chitinase produced by some B. thuringiensis strains had a molecular weight of about 61 kDa. The bioassay results indicated that the chitinase-producing B. thuringiensis strains could enhance the insecticidal activity of B. thuringiensis strain DL5789 against S. exigua larvae, with an enhancing ratio of 2AE35-fold. Conclusion: This study demonstrated that chitinase was widely produced in B. thuringiensis strains and some of the strains could enhance the toxicity of active B. thuringiensis strain. Significance and Impact of the Study: This is the first investigation devoted exclusively to analyse the distribution of chitinase in B. thuringiensis. It infers that the chitinase produced by B. thuringiensis might play a role in the activity of the biopesticide.

Journal ArticleDOI
TL;DR: It is speculated that high expression and intracellular localization of rice chitinase may be involved in enhancing the resistance of transgenic plants to gray mold.

Journal ArticleDOI
TL;DR: In this paper, the chitinase activity in Aedes aegypti guts was analyzed using SDS-PAGE gel analysis, and the results showed that both chITinase and beta-N-acetylglucosaminidase are present and physiologically active.

Journal ArticleDOI
TL;DR: Because during the ripening of prematurely harvested bananas, similar changes take place as in the in situ ripening bananas, CRP present in immature fruits is a sufficient source of amino acids for a quasi-normal synthesis of ripening-associated proteins.
Abstract: Analyses of the protein content and composition revealed dramatic changes in gene expression during in situ banana (Musa spp.) fruit formation/ripening. The total banana protein content rapidly increases during the first 60 to 70 d, but remains constant for the rest of fruit formation/ripening. During the phase of rapid protein accumulation, an inactive homolog of class III chitinases accounts for up to 40% (w/v) of the total protein. Concomitant with the arrest of net protein accumulation, the chitinase-related protein (CRP) progressively decreases and several novel proteins appear in the electropherograms. Hence, CRP behaves as a fruit-specific vegetative storage protein that accumulates during early fruit formation and serves as a source of amino acids for the synthesis of ripening-associated proteins. Analyses of individual proteins revealed that a thaumatin-like protein, a β-1,3-glucanase, a class I chitinase, and a mannose-binding lectin are the most abundant ripening-associated proteins. Because during the ripening of prematurely harvested bananas, similar changes take place as in the in situ ripening bananas, CRP present in immature fruits is a sufficient source of amino acids for a quasi-normal synthesis of ripening-associated proteins. However, it is evident that the conversion of CRP in ripening-associated proteins takes place at an accelerated rate, especially when climacteric ripening is induced by ethylene. The present report also includes a discussion of the accumulation of the major banana allergens and the identification of suitable promoters for the production of vaccines in transgenic bananas.

Journal ArticleDOI
TL;DR: Results indicate that E146 probably functions as an acid/base catalyst in the hydrolytic mechanism, as do homologous residues in other glycosyl hydrolases, which includes Manduca sexta chitinase as a member.

Journal ArticleDOI
TL;DR: The unique characteristics of the purified chitinase include high molecular weight, nearly neutral optimum pH, protease activity, and antimicrobial activity with bacteria and fungal phytopathogens.
Abstract: Monascus purpureus CCRC31499 produced an antimicrobial chitinase when it was grown in a medium containing shrimp and crab shell powder (SCSP) of marine wastes. An extracellular antimicrobial chitinase was purified from the culture supernatant to homology. The chitinase had a molecular weight of approximately 81,000 and a pI of 5.4. The optimal pH, optimum temperature, and pH stability of the chitinase were pH 7, 40 degrees C, and pH 6-8, respectively. The activity of the chitinase was activated by Fe(2+) and strongly inhibited by Hg(2+). The unique characteristics of the purified chitinase include high molecular weight, nearly neutral optimum pH, protease activity, and antimicrobial activity with bacteria and fungal phytopathogens. This is also the first report of isolation of a chitinase from a Monascus species.

Journal ArticleDOI
TL;DR: Finely powdered alpha- andbeta-chitin can be completely hydrolyzed with chitinase (EC 3.2.1.14) and beta-N-acetylhexosaminidase ( EC 3.1-2.52) for the production of 2-acetamido-2-deoxy-D-glucose (GlcNAc).

Journal ArticleDOI
TL;DR: The secretion of hydrolytic enzymes by yeasts was studied in batch cultures amended with different carbon sources (glucose, laminarin, and Botrytis cinerea cell wall preparation) and it was observed that the enzymes may constitute a relatively small part of the total protein secreted.

Journal ArticleDOI
TL;DR: This in situ hybridization study first revealed cellular localization of the gut-type chitinase in the mouse and chicken, suggesting its role in digestion of chitIn-containing foods as well as defense against chit in-coated microorganisms and parasites.
Abstract: Recently, the second mammalian chitinase, designated acidic mammalian chitinase (AMCase), has been identified in human, mouse, and cow. In contrast to the earlier identified macrophage-derived chitinase (chitotriosidase), this chitinase is richly expressed in the gastrointestinal (GI) tract, suggesting its role in digestion of chitin-containing foods as well as defense against chitin-coated microorganisms and parasites. This in situ hybridization study first revealed cellular localization of the gut-type chitinase in the mouse and chicken. In adult mice, the parotid gland, von Ebner's gland, and gastric chief cells, all of which are exocrine cells of the serous type, expressed the gut chitinase mRNA. In the chicken, oxyntico-peptic cells in glandular stomach (proventriculus) and hepatocytes expressed the chitinase mRNA. Because cattle produce the gut chitinase (chitin-binding protein b04) only in the liver, the gut chitinases in mammals and birds have three major sources of production, i.e., the salivary ...

Journal ArticleDOI
TL;DR: The antifungal activities of rye seed chitinase-a and -c were studied in detail using two different bioassays with Trichoderma sp.
Abstract: The antifungal activities of rye seed chitinase-a (RSC-a, class I) and -c (RSC-c, class II) were studied in detail using two different bioassays with Trichoderma sp. as well as binding and degradation experiments with the cell walls prepared from its mycelia. RSC-a inhibited more strongly the re-extension of the hyphae, containing mainly mature cells, than RSC-c did. Upon incubation of the fungus with fluorescent chitinases, FITC-labeled RSC-a was found to be located in the hyphal tips, lateral walls, and septa, while FITC-labeled RSC-c was only in the hyphal tip. RSC-a had a greater affinity for the cell walls than RSC-c. RSC-a liberated a larger amount of reducing sugar from the cell walls than RSC-c did. These results inferred that RSC-a first binds to the lateral walls and septa, consisting of the mature cell walls, and degrades mature chitin fiber, while RSC-c binds only to the hyphal tip followed by degradation of only nascent chitin. As a result, RSC-a inhibited fungal growth more effectively than RSC-c. Furthermore, it was suggested that the chitin-binding domain in RSC-a assists the antifungal action of RSC-a by binding to the fungal hypha.

Journal ArticleDOI
TL;DR: Binding experiments and isothermal titration calorimetry assays demonstrated that ChBDChiC binds to insoluble chit in, soluble chitin, cellulose, and N-acetylchitohexaose (roughly in that order) and appears to contribute more importantly to antifungal properties than to catalytic activities.
Abstract: Chitinase C (ChiC) is the first bacterial family 19 chitinase discovered in Streptomyces griseus HUT6037. While it shares significant similarity with the plant family 19 chitinases in the catalytic domain, its N-terminal chitin-binding domain (ChBD(ChiC)) differs from those of the plant enzymes. ChBD(ChiC) and the catalytic domain (CatD(ChiC)), as well as intact ChiC, were separately produced in E. coli and purified to homogeneity. Binding experiments and isothermal titration calorimetry assays demonstrated that ChBD(ChiC) binds to insoluble chitin, soluble chitin, cellulose, and N-acetylchitohexaose (roughly in that order). A deletion of ChBD(ChiC) resulted in moderate (about 50%) reduction of the hydrolyzing activity toward insoluble chitin substrates, but most (about 90%) of the antifungal activity against Trichoderma reesei was abolished by this deletion. Thus, this domain appears to contribute more importantly to antifungal properties than to catalytic activities. ChBD(ChiC) itself did not have antifungal activity or a synergistic effect on the antifungal activity of CatD(ChiC) in trans.

Journal ArticleDOI
TL;DR: A molecular mechanism for cuticle digestion during the moulting process is proposed, using differential display to identify genes that are regulated by juvenile hormone in the epidermis of the beetle Tenebrio molitor and indirectly induced TmChit5 mRNA expression.
Abstract: We have used differential display to identify genes that are regulated by juvenile hormone in the epidermis of the beetle Tenebrio molitor One of the genes encodes T molitor chitinase 5 (TmChit5), a chitinase possessing an unusual structure Sequence analysis of TmChit5 identified five 'chitinase units' of approx 480 amino acids with similarity to chitinase family 18 These units are separated by less conserved regions containing putative PEST (rich in proline, glutamic acid, serine and threonine) sequences, putative chitin-binding domains and mucin domains Northern-blot analysis identified a single transcript of approx 9 kb, whose abundance correlated with that of 20-hydroxyecdysone during metamorphosis Injection of pupae with 20-hydroxyecdysone alone, or in combination with cycloheximide, indicated that TmChit5 expression is directly induced by the hormone Further experiments indicated that methoprene (a juvenile hormone analogue) indirectly induced TmChit5 mRNA expression On the basis of the present results and previous studies, we propose a molecular mechanism for cuticle digestion during the moulting process

Journal Article
TL;DR: Chitinase produced by P. illinoisensis KJA-424 caused the lysis of M. incognita eggshell and resulted in the inhibition of egg hatching in vitro, and chitinolytic activity significantly increased for the first 2 days of incubation.
Abstract: A bacterium having strong chitinolytic activity on 02% colloidal chitin-containing agar medium was isolated from coastal soil in Korea Based on the nucleotide sequence of a conserved segment of a 16S rRNA gene, the bacterium was identified as Paenibacillus illinoisensis KJA-424 The population of P illinoisensis KJA-424 and chitinase activity significantly increased for the first 2 days of incubation On SDS-PAGE analysis with 001% glycol chitin, three protein bands (63, 54, and 38 kDa) with chitinolytic activity were detected The effect of P illinoisensis KJA-424 on the egg hatch of root-knot nematode (Meloidogyne incognita) was investigated After 7 days of incubation with the chitinase- producing P illinoisensis KJA-424, none of the eggs hatched, whereas a 398% egg hatching rate was observed in the water control Inverted and scanning electron microscopic observations demonstrated that P illinoisensis KJA-424 deformed and destroyed the eggshell of M incognita In conclusion, chitinase produced by P illinoisensis KJA-424 caused the lysis of M incognita eggshell and resulted in the inhibition of egg hatching in vitro

OtherDOI
TL;DR: This chapter discusses the chemical structure of chitin and chitosan, the phytochemical properties of polyphenolic Pigments, and some of the mechanisms used to derive polyphenols.
Abstract: Introduction Chemical Structure Chitin Chitosan Polyphenolic Pigments Occurrence Physiological Function Chemical Analysis and Detection Biosynthesis of Chitin and Chitosan Chitin Synthases (CS) Glucan Transferase Chitin Deacetylase (CDA) Biodegradation Chitinase Chitosanases Exo-β-d-glucosaminidases Biotechnological Production Screening for Chitosan Producer Strains Isolation of Chitin and Chitosan from Fungal Biomass Production of CDA Applications Adsorption of Coloring Matters Metal Ion Adsorption Healthcare Outlook Patents Acknowledgements Keywords: N-acetylglucosaminidase; antifungals; chitin; chitinases; chitin deacetylase; chitobiase; chitobiosidase; chitosan; chitosanase; fungal biomass; glucosaminidase; hexosaminidase; fungi; FT-IR spectroscopy; glucans; lysozyme; melanin; polyphenols

Journal ArticleDOI
TL;DR: Results suggest involvement of the chitinase gene in protection of pepper plants against the pathogen, but also document cross talk with stress signals mediated by ABA, high salinity and drought.
Abstract: Northern blot and in situ hybridization analyses revealed that a pepper basic class II chitinase gene (CAChi2) is constitutively expressed in floral organs and root endodermis, but not in leaf, stem and fruit of pepper. Resistance of pepper leaves to Colletotrichum coccodes infection at a late growth stage was correlated with induction of beta-1,3-glucanase and PR-1 mRNA, but not of chitinase (CAChi2) mRNA. Transcriptional activation of the CAChi2 gene in pepper leaves occurred during anthracnose development. The CAChi2 transcripts were mainly localized in phloem cells of vascular tissues of pepper leaves infected with C. coccodes. The CAChi2 gene was also differentially induced in leaf and stem tissue by treatment with abscisic acid (ABA), sodium chloride or drought. Strong accumulation of the CAChi2 transcripts occurred in pepper stem tissues due to high salt and drought, and also due to treatment with ABA. These results suggest involvement of the chitinase gene in protection of pepper plants against the pathogen, but also document cross talk with stress signals mediated by ABA, high salinity and drought.

Journal ArticleDOI
TL;DR: Hydrolytic mechanisms of family 18 chitinases from rice and Bacillus circulans WL-12 were comparatively studied by a combination of HPLC analysis of the reaction products and theoretical calculation of reaction time-courses, showing that minor structural differences between plant and microbial enzymes appear to result in such functional variations.
Abstract: Hydrolytic mechanisms of family 18 chitinases from rice (Oryza sativa L.) and Bacillus circulans WL-12 were comparatively studied by a combination of HPLC analysis of the reaction products and theoretical calculation of reaction time-courses. All of the enzymes tested produced beta-anomers from chitin hexasaccharide [(GlcNAc)(6)], indicating that they catalyze the hydrolysis through a retaining mechanism. The rice chitinases hydrolyzed predominantly the fourth and fifth glycosidic linkages from the nonreducing end of (GlcNAc)(6), whereas B. circulans chitinase A1 hydrolyzed the second linkage from the nonreducing end. In addition, the Bacillus enzyme efficiently catalyzed transglycosylation, producing significant amounts of chitin oligomers larger than the initial substrate, but the rice chitinases did not. The time-courses of (GlcNAc)(6) degradation obtained by HPLC were analyzed by theoretical calculation, and the subsite structures of the rice chitinases were identified to be (-4)(-3)(-2)(-1)(+1)(+2). From the HPLC profile of the reaction products previously reported [Terwisscha van Scheltinga et al. (1995) Biochemistry 34, 15619-15623], family 18 chitinase from rubber tree (Hevea brasiliensis) was estimated to have the same type of subsite structure. Theoretical analysis of the reaction time-course for the Bacillus enzyme revealed that the enzyme has (-2)(-1) (+1)(+2)(+3)(+4)-type subsite structure, which is identical to that of fungal chitinase from Coccidioides immitis [Fukamizo et al. (2001) Biochemistry 40, 2448-2454]. The Bacillus enzyme also resembled the fungal chitinase in its transglycosylation activity. Minor structural differences between plant and microbial enzymes appear to result in such functional variations, even though all of these chitinases are classified into the identical family of glycosyl hydrolases.