Specific Activity Of Chitinase Research Articles

Reprogramming the chiA expression profile of Autographa californica multiple nucleopolyhedrovirus

Expression of chiA and v-cath RNA and enzyme activity in wild-type Autographa californica multiple nucleopolyhedrovirus (AcMNPV) was compared with that of recombinant AcMNPV viruses reprogrammed for expression of the endogenous chiA. To establish a baseline for our recombinant AcMNPV studies, we compared, for the first time, the temporal expression profiles of both AcMNPV chiA transcription and translation simultaneously. The rate of intracellular chitinase accumulation during AcMNPV infection followed the same pattern observed for chiA transcription but was delayed by about 6 h. Replacement of 21 nucleotides containing the native late chiA and v-cath promoters with a selectable polh-EGFP cassette was sufficient to eliminate expression of both chiA and v-cath. Viruses were generated that express chiA from either the late p6.9 or very late polh promoters of AcMNPV, replacing the native chiA promoter. There was a marked difference in the temporal chiA transcription profiles from the native, p6.9 and polh promoters, resulting in respective specific activities of chitinase at 48 h p.i. of 62, 160 and 219 mU (mg lysate total protein)(-1). Based on temporal analysis of v-cath transcription by Northern blot, AcMNPV v-cath was transcribed from 9 h p.i. in Sf21 cells. However, expression of v-cath RNA or enzyme from a reconstructed v-cath promoter in the chiA-reprogrammed viruses was not detected at 48 h of virus replication. Reprogramming for increased chitinase (and putatively cathepsin) expression with native baculovirus promoters might provide a means for designing environmentally benign biological insecticides.

Agrobacterium -mediated transformation of cotton (Gossypium hirsutum) using a heterologous bean chitinase gene

Cotton (Gossypium hirsutum L., var. Coker 312) hypocotyl explants were transformed with three strains of Agrobacterium tumefaciens, LBA4404, EHA101 and C58, each harboring the recombinant binary vector pBI121 containing the chi gene insert and neomycin phosphotransferase (nptII) gene, as selectable marker. Inoculated tissue sections were placed onto cotton co-cultivation medium. Transformed calli were selected on MS medium containing 50 mg l−1 kanamycin and 200 mg l−1 cepotaxime. Putative calli were subsequently regenerated into cotton plantlets expressing both the kanamycin resistance gene and βglucuronidase (gus) as a reporter gene. Polymerase chain reaction was used to confirm the integration of chi and nptII transgenes in the T1 plants genome. Integration of chi gene into the genome of putative transgenic was further confirmed by Southern blot analysis. ‘Western’ immunoblot analysis of leaves isolated from T0 transformants and progeny plants (T1) revealed the presence of an immunoreactive band with MW of approximately 31 kDa in transgenic cotton lines using anti-chitinase-I polyclonal anti-serum. Untransformed control and one transgenic line did not show such an immunoreactive band. Chitinase specific activity in leaf tissues of transgenic lines was several folds greater than that of untransformed cotton. Crude leaf extracts from transgenic lines showed in vitro inhibitory activity against Verticillium dahliae.Transgenic plants currently growing in a greenhouse and will be bioassayed for improved resistance against V. dahlia the causal against of verticilliosis in cotton.

Increased antifungal and chitinase specific activities of Trichoderma harzianum CECT 2413 by addition of a cellulose binding domain.

Trichoderma harzianum is a widely distributed soil fungus that antagonizes numerous fungal phytopathogens. The antagonism of T. harzianum usually correlates with the production of antifungal activities including the secretion of fungal cell walls that degrade enzymes such as chitinases. Chitinases Chit42 and Chit33 from T. harzianum CECT 2413, which lack a chitin-binding domain, are considered to play an important role in the biocontrol activity of this strain against plant pathogens. By adding a cellulose-binding domain (CBD) from cellobiohydrolase II of Trichoderma reesei to these enzymes, hybrid chitinases Chit33-CBD and Chit42-CBD with stronger chitin-binding capacity than the native chitinases have been engineered. Transformants that overexpressed the native chitinases displayed higher levels of chitinase specific activity and were more effective at inhibiting the growth of Rhizoctonia solani, Botrytis cinerea and Phytophthora citrophthora than the wild type. Transformants that overexpressed the chimeric chitinases possessed the highest specific chitinase and antifungal activities. The results confirm the importance of these endochitinases in the antagonistic activity of T. harzianum strains, and demonstrate the effectiveness of adding a CBD to increase hydrolytic activity towards insoluble substrates such as chitin-rich fungal cell walls.

Oxidative burst elicited by Bacillus mycoides isolate Bac J, a biological control agent, occurs independently of hypersensitive cell death in sugar beet.

Response of sugar beet cultivars C40 and USH11 to syringe infiltration of live and dead Bacillus mycoides isolate Bac J, a biological control agent, and virulent and avirulent isolates of Erwinia carotovora pv. betavasculorum was measured by monitoring systemic acquired resistance control of Cercospora beticola, specific activity of chitinase and beta-glucanase, the oxidative burst, and hypersensitive cell death at the infiltration site. Priming sugar beet with B. mycoides Bac J (1 x 10(8) cells/ml) and avirulent isolates of E. carotovora pv. betavasculorum (1 x 10(6) cells/ml) reduced C. beticola symptoms by nearly 70% on distal, untreated leaves. Systemic resistance responses elicited by live B. mycoides Bac J and avirulent E. carotovora pv. betavasculorum isolates, measured by assays for chitinase and beta-glucanase, were statistically equivalent, and biphasic hydrogen peroxide production was observed. Although similar in timing, the second hydrogen peroxide burst was twofold lower for B. mycoides Bac J than for avirulent E. carotovora pv. betavasculorum. Hypersensitive cell death was elicited by avirulent E. carotovora pv. betavasculorum but not B. mycoides Bac J. An oxidative burst was elicited by spray-applied B. mycoides Bac J under both light and green light conditions, indicating that the signal produced by B. mycoides Bac J was not reliant on the stomata for entry into sugar beet. A working model for signal delivery and systemic resistance induction by B. mycoides Bac J in sugar beet is proposed.

Heterologous expression and characterization of class III chitinases from rice ( Oryza sativa L.)

Acidic (OsChib1a) and basic (OsChib1b) class III chitinases from rice ( Oryza sativa L.), sharing 70% of the identical amino acid residues each other, were expressed from the corresponding cDNAs in Pichia pastoris and purified homogenously. Both OsChib1a and OsChib1b degraded actively glycol chitin over colloidal chitin at the optimum pH of 4.3 and 8.3, respectively. OsChib1b had lower specific chitinase activity than OsChib1a, but it showed a strong lytic activity and significant antifungal activity: no lytic and antifungal activity was observed for OsChib1a. Experiments with N-acetyl chitooligosaccharides showed that OsChib1a hydrolyzed (GlcNAc) 6 efficiently to yield (GlcNAc) 2 as the major product, while OsChib1b hydrolyzed (GlcNAc) 6 to yield both (GlcNAc) 2 and (GlcNAc) 4. Possible structures responsible for their distinct catalytic properties are discussed.

Induced chitinase activity in resistant wheat leaves inoculated with an incompatible race of Puccinia striiformis f. sp. tritici, the causal agent of yellow rust disease.

Chitinase specific activity was measured spectrophotometrically in wheat leaf tissues during the compatible and incompatible interactions with Puccinia striiformis f. sp. tritici, the causal agent of yellow rust disease. The wheat cultivar, Federation* 4/Kavkaz, was inoculated with virulent (134E134A+) or avirulent (4EOA+) races of P. striiformis f. sp. tritici in the first leaf stage. The results showed that chitinase activity pattern was similar in both compatible and incompatible interactions up to 72 hrs after inoculation. However, the specific activity increased rapidly in the incompatible reaction thereafter. In susceptible reaction, chitinase activity gradually declined after 72 hrs post-inoculation reaching a level similar to that in the control plants two weeks after inoculation. Chitinase specific activity in resistance response was at least three times greater than that in the susceptible reaction two weeks following the inoculation. Electrophoresis of native polyacrylamide gel impregnated with 0.1% (w/v) glycol chitin as the substrate revealed the presence of eight chitinase isoforms with relative electrophoretic mobility (Rm) values ranging from 0.11 to 0.64 in the resolving gel.

Lytic enzyme complex of an antagonistic Bacillus sp. X-b: isolation and purification of components

Bacillus sp. X-b, a biocontrol agent against certain plant pathogenic fungi, secretes a complex of hydrolytic enzymes, composed of chitinase, chitosanase, laminarinase, lipase and protease. Homogenized mycelium of basidiomycete Macrolepiota procera induced activities of these enzymes more effectively than colloidal chitin or partially purified cell walls of another basidiomycete Polyporus squamosus. Subjected to a multi-step purification, the specific activity of chitinase increased 36-fold, chitosanase 69-fold, lipase 44-fold and laminarinase 15-fold. Partially purified chitinase showed two major bands with molecular masses of 46 000 and 35 000 on sodium dodecyl sulfate–polyacrylamide gel electrophoresis while chitosanase and lipase appeared as single bands with molecular masses of 27 000 and 62 000, respectively.

Effect of chitin sources on production of chitinase and chitosanase byStreptomyces griseus HUT 6037

The advantage of usingStreptomyces griseus HUT 6037 in the production of chitinase or chitosanase is that the organism is capable of hydrolyzing amorphous or crystal-line chitin and chitosan according to the type of the substrate used. We investigated the effects of the enzyme induction time and chitin sources, CM-chitosan and deacetylated chitosan (degree of deacetylation 75–99%), on production of chitosanase. We found that this strain accumulated chitosanase when cells were grown in the culture medium containing chitosanaceous substrates instead of chitinaceous substrates. The highest chitosanase activity was obtained at 4 days of cultivation with 99% deacetylated chitosan. Soluble chitosan (53% deacetylated chitosan) was found to induce chitinase as well as chitosanase. The specific activities of chitinase and chitosanase were 0.91 and 1.33 U/mg protein at 3 and 5 days, respectively. From the study of the enzymatic digestibility of various degrees of deacetylated chitosan, it was found that (GlcN)3, (GlcN)4 and (GlcN)5 were produced during the enzymatic hydrolysis reaction. The results of this study suggested that the sugar composition of (GlcN)3 was homogeneous and those of (GlcN)4 and (GlcN)5 were heterogeneous.

Chitinases from the Plant Disease Biocontrol Agent, Stenotrophomonas maltophilia C3

ABSTRACT Stenotrophomonas maltophilia strain C3, a biocontrol agent of Bipolaris sorokiniana in turfgrass, produced chitinases in broth media containing chitin. Chitinases were partially purified from culture fluid by ammonium sulfate precipitation and chitin affinity chromatography. The chromatography fraction with the highest specific chitinase activity was inhibitory to conidial germination and germ-tube elongation of B. sorokiniana, but it was less inhibitory than the protein fraction or the raw culture filtrate. The fraction exhibited strong exochitinase and weak endo-chitinase activity. Optimum temperature and pH for chitinase activity were 45 to 50 degrees C and 4.5 to 5.0, respectively. Chitinase activity was inhibited by Hg(2+) and Fe(3+), but not by other metal ions or enzyme inhibitors. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the chromatography fraction revealed the presence of five protein bands of 25, 32, 48, 65, and 75 kDa. Partial amino acid sequences of the 32-, 65-, and 75-kDa proteins indicated that they are homologous to known bacterial chitinases. There was no homology found in the partial amino acid sequences of the 25- and 48-kDa proteins to any known chitinases. Five chitinase-active proteins were detected in the protein and chromatography fractions by activity gels, but when each protein was extracted and re-electrophoresed separately under denaturing conditions, only 32- or 48-kDa proteins were revealed. It was concluded that strain C3 produces at least two chitinases that are antifungal.

Chitinase Activity in Tall Fescue Seedlings as Affected by Cultivar, Seedling Development, and Ethephon

Recent reports indicate that tall fescue (Festuca arundinacea Schreb.) may be selected for increased disease resistance with the use of a marker such as chitinase, a defense protein associated with disease resistance in tall fescue. The objective of this study was to determine if chitinase activity in tall fescue cultivars differs consistently across seedling stage, and to determine if chitinase activity could be increased with ethephon ([2-chloroethyl]phosphonic acid), a growth regulator used as a chemical elicitor. Ten cultivars of tall fescue were planted in a greenhouse, and seedlings were harvested at 14, 28, and 42 d after germination. Seedlings were treated with and without ethephon 3 d prior to each harvest. Foliage was analyzed for total and specific chitinase activity. Both total and specific chitinase activity differed (P < 0.01) among cultivars and seedling stages. Highest ranking cultivars expressed at least 16% more total chitinase activity and 18% more specific activity than the lowest ranking cultivars. Though chitinase activity changed drastically over seedling development, there were no cultivar × seedling stage interactions (P < 0.01) for total or specific activity. Ethephon increased total and specific activity only at the 0.06 and 0.07 probability level and was far less effective than biological elicitors used to increase chitinase in previous studies. We concluded that chitinase could serve as a consistent marker among tall fescue cultivars across seedling stages, but a more effective chemical elicitor would be desirable to increase chitinase activity.

Effective production of chitinase and chitosanase byStreptomyces griseus HUT 6037 using colloidal chitin and various degrees of deacetylation of chitosan

The advantages of the organismStreptomyces griseus HUT 6037 is that the chitinase and chitosanase using chitinaceouse substrate are capable of hydrolyzing both amorphous and crystalline chitin and chitosan. We attempted to investigate the optimization of induction protocol for high-level production and secretion of chitosanase and the influence of chitin and partially deacetylated chitosan sources (75–99% deactylation). The maximum specific activity of chitinase has been found at 5 days cultivation with the 48 hours induction time using colloidal chitin as a carbon source. To investigate characteristic of chitosan activity according to substrate, we used chitosan with various degree of deacetylation as a carbon source and found that this strain accumulates chitosanase in the culture medium using chitosanaceous substrates rather than chitinaceous substrates. The highest chitosanase activity was also presented on 4 days with 99% deacetylated chitosan. The partially 53% deacetylated chitosan can secrete both chitinase and chitosanase which was defined as a soluble chitosan. The specific activities of chitinase and chitosanase were 0.89 at 3 days and 1.33 U/mg protein at 5 days, respectively. It indicate that chitosanase obtained fromS. griseus HUT 6037 can hydrolyze GlcNAc-GlcN and GlcN-GlcN linkages by exo-splitting manner. This activity increased with increasing degree of deacetylation of chitosan. It is the first attempt to investigate the effects of chitosanase on various degrees of deacetylations of chitosan byS. griseus HUT 6037. The highest specific activity of chitosanase was obtained with 99% deacetylated chitosan.

Expression inEscherichia coliof a Gene Encoding a Thermostable Chitinase fromStreptomyces thermoviolaceusOPC-520

An expression plasmid for a thermostable chitinase gene from S. thermoviolaceus OPC-520 in E. coli was constructed. A cloned chitinase (Chi40) was purified from the periplasmic space of E. coli harboring the expression plasmid. The N-terminal sequence of Chi40 was 11 amino acids longer than that of chitinase from S. thermovilaceus OPC-520 (ST chitinase), however, a loss or addition of the amino acid residues did not affect the enzymatic properties. The mutations of Asp-145 and Glu-147 drastically decreased the specific activity of chitinase from the wild type, indicating that both amino acid residues are the best candidates for the essential catalytic residues of Chi40.

Determination of Chitinase Activity in Tall Fescue by Near Infrared Reflectance Spectroscopy

New cultivars of pasture‐type tall fescue (Festuca arundinacea Schreber) lack the fungal endophyte, Acremonium coenophialum Morgan‐Jones &amp; W. Gams. Although Acremonium‐free cultivars are less toxic to livestock than Acremonium‐infected cultivars, they are less disease tolerant. Acremonium‐free cultivars may be improved for disease tolerance using a biochemical marker such as chitinase, a defense hydrolase associated with disease resistance in many crops. The objective of this research was to measure chitinase activity in tall fescue seedlings by near infrared reflectance Spectroscopy (NIRS). Ninety‐nine seedling samples were freeze‐dried, ground, and analyzed for total and specific chitinase activity using tritiated chitin as a substrate. Near infrared spectra were recorded for each sample, and an NIRS equation was developed by regressing radiochemical data against spectral data; regression procedures included forward stepwise multiple regression and modified partial least squares (MPLS). In optimum equations, standard errors of calibration and validation were near or below 10% of the mean, similar to errors observed in routine chemical analysis of chitinase. The optimum equation used MPLS to predict specific activity, resulting in a coefficient of determination of 0.90 and a mean and standard error of 88.8 ± 7.2 disintegrations min−1 mg−1 protein. The NIRS‐chitinase procedure is accurate and efficient. Once a spectrophotometer is calibrated, the NIRS procedure is at least 10 tunes faster than chemical procedures, permitting analysis in 60 s per sample.

Carbon source control on β-glucanases, chitobiase and chitinase from Trichoderma harzianum

The cell-wall degrading enzymes β-glucanase and chitinase have been suggested to be essential for the mycoparasitic action of Trichoderma species against plant fungal pathogens. For this reason, the production in different carbon sources of extracellular β-1,3-glucanase, β-1,6-glucanase, chitobiase and chitinase was studied in a mycoparasitic strain of Trichoderma harzianum. Maximal β-glucanase specific activities were detected in media supplemented with either pustulan (β-1,6-glucan), nigeran (α-1,3-glucan alternating with α-1,4-glucan), chitin or Saccharomyces cerevisiae or Botrytis cinerea purified cell walls, whereas the highest chitinase specific activity was obtained in medium supplemented with chitin. Furthermore, β-glucanase, chitobiase and chitinase activities showed an increase parallel to increasing concentrations of either pustulan or chitin added to the cultures, although the extent of this increase varied with the different enzymes. The culture filtrates of T. harzianum grown in these carbon sources also showed lytic activity on purified cell walls of S. cerevisiae and B. cinerea. The enzyme synthesis seemed to be repressed by glucose, 8-hydroxyquinoline, which inhibits transcription, or cycloheximide, an inhibitor of protein synthesis.

Biological Control Activity of Three Trichoderma Isolates Against Fusarium Wilts of Cotton and Muskmelon and Lack of Correlation with their Lytic Enzymes

The enzymatic activity and the biocontrol ability of two new isolates of Trichoderma spp. (T-68 and Gh-2) were compared in laboratory and glasshouse experiments with a previously studied T. harzianum strain (T-35). In dual culture tests with Fusarium oxysporum f. sp. melonis and F. oxysporum f. sp. vasinfectum , isolates T-68 and Gh-2 overgrew the colonies of Fusarium , whereas T-35 failed to parasitize both wilt pathogens. Under glasshouse conditions, the three isolates of Trichoderma were effective in controlling Fusarium wilt of cotton but only T-35 was effective against F. oxysporum f. sp. melonis on muskmelon. When the three Trichoderma isolates were grown on liquid media containing laminarin, colloidal chitin or F. oxysporum f. sp. melonis cell walls as sole carbon sources, maximum β-1,3-glucanase and chitinase specific activity in the culture filtrates of all fungi was reached after 72h of incubation. When culture filtrates of the three Trichoderma isolates were incubated with freeze-dried mycelium of F. oxysporum f. sp. melonis or F. oxysporum f. sp. vasinfectum , different concentrations of glucose and N-acetyl-D-glucosamine were released. Overall no correlation was found between enzymatic activity and the biocontrol capability against Fusarium wilt on muskmelon and cotton.

Chitinase activity and VA-mycorrhiza development

Chitinase activity was measured in roots of leek during development of VA-mycorrhizal symbiosis with Glomus versiforme. During the early stages of infection the specific activity of chitinase was higher in mycorrhizal roots than in the uninfected controls. However, when the symbiosis was established, the mycorrhizal roots contained less chitinase than control roots. Immunochemical and immunocytochemical methods were used to investigate the localization of the chitinase which was found in the vacuoles and in the extracellular spaces but not on the fungal cell walls.

Chitinase in roots of mycorrhizal Allium porrum: regulation and localization

Chitinase (EC 3.2.1.14) activity was measured in roots of Allium prorrum L. (leek) during development of a vesicular-arbuscular mycorrhizal symbiosis with Glomus versiforme (Karst.) Berch. During the early stages of infection, between 10 and 20 d after inoculation, the specific activity of chitinase was higher in mycorrhizal roots than in the uninfected controls. However, 60-90 d after inoculation, when the symbiosis was fully established, the mycorrhizal roots contained much less chitinase than control roots. Chitinase was purified from A. porrum roots. An antiserum against beanleaf chitinase was found to cross-react specifically with chitinase in the extracts from non-mycorrhizal and mycorrhizal A. porrum roots. This antiserum was used for the immunocytochemical localization of the enzyme with fluorescent and gold-labelled probes. Chitinase was localized in the vacuoles and in the extracellular spaces of non-mycorrhizal and mycorrhizal roots. There was no immunolabelling on the fungal cell walls in the intercellular or the intracellular phases. It is concluded that the chitin in the fungal walls is inaccessible to plant chitinase. This casts doubts on the possible involvement of this hydrolase in the development of the mycorrhizal fungus. However, fungal penetration does appear to cause a typical defense response in the first stages that is later depressed.

Extracellular localization of chitinase in cucumber

The localization of systemically induced chitinase activity was examined in the second leaves of cucumber plants that had been infected on the first leaf with tobacco necrosis virus. Leaf pieces were infiltrated with a buffered sodium chloride solution, and the intercellular fluid was subsequently extracted by centrifugation. Chitinase had a much higher specific activity in extracts of the intercellular fluid than in leaf homogenates. The specific activity of chitinase in protoplasts obtained from the leaves was only 5% of that in tissue homogenates. These data indicate that most of the chitinase activity is located in the extracellular space.

Vacuolar Localization of Ethylene-Induced Chitinase in Bean Leaves

The localization of ethylene-induced endochitinase was studied in bean (Phaseolus vulgaris L. cv Saxa) leaves. The specific activity of chitinase in mesophyll protoplasts isolated from the leaves was as high as in tissue homogenates, indicating that most of the enzyme was located intracellularly. Vacuoles isolated and purified from the protoplasts were found to contain most of the intracellular chitinase activity.

Chitinase activity in the crystalline style of the american oyster Crassostrea virginica

1. 1. Presence of chitinase in Crassostrea virginica crystalline styles was established. 2. 2. Specific activity of chitinase tended to increase towards the anterior portion of the style. 3. 3. Chitinase activity was not stimulated by chitin additions to 1 μm filtered sea water. 4. 4. Kaolin additions to the diet resulted in doubling chitinase specific activity.