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Chitinolytic Activities (chitinolytic + activity)
Selected AbstractsChitinolytic activities in Bacillus thuringiensis and their synergistic effects on larvicidal activityJOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2002M. Liu 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. Thirty-eight strains produced different levels of chitinase at pH 7·0, and so did 17 strains at pH 10·0. 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 2·35-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. [source] Chitinolytic activity of endophytic Streptomyces and potential for biocontrolLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2008M.C. Quecine Abstract Aims:, Biological sources for the control of plant pathogenic fungi remain an important objective for sustainable agricultural practices. Actinomycetes are used extensively in the pharmaceutical industry and agriculture owing to their great diversity in enzyme production. In the present study, therefore, we evaluated chitinase production by endophytic actinomycetes and the potential of this for control of phytopathogenic fungi. Methods and Results:, Endophytic Streptomyces were grown on minimum medium supplemented with chitin, and chitinase production was quantified. The strains were screened for any activity towards phytopathogenic fungi and oomycetes by a dual-culture in vitro assay. The correlation between chitinase production and pathogen inhibition was calculated and further confirmed on Colletotrichum sublineolum cell walls by scanning electron microscopy. Conclusions:, This paper reports a genetic correlation between chitinase production and the biocontrol potential of endophytic actinomycetes in an antagonistic interaction with different phytopathogens, suggesting that this control could occur inside the host plant. Significance and Impact of the Study:, A genetic correlation between chitinase production and pathogen inhibition was demonstrated. Our results provide an enhanced understanding of endophytic Streptomyces and its potential as a biocontrol agent. The implications and applications of these data for biocontrol are discussed. [source] Cloning and comparison of phylogenetically related chitinases from Listeria monocytogenes EGD and Enterococcus faecalis V583JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2009J.J. Leisner Abstract Aims:, To compare enzymatic activities of two related chitinases, ChiA and EF0361, encoded by Listeria monocytogenes and Enterococcus faecalis, respectively. Methods and Results:, The chiA and EF0361 genes were amplified by PCR, cloned and expressed with histidine tags, allowing easy purification of the gene products. ChiA had a molecular weight as predicted from the amino acid sequence, whereas EF0361 was 1840 Da lower than expected because of C-terminal truncation. The ChiA and EF0361 enzymes showed activity towards 4-nitrophenyl N,N,-diacetyl-,- d -chitobioside with Km values of 1·6 and 2·1 mmol l,1, respectively, and kcat values of 21·6 and 6·5 s,1. The enzymes also showed activity towards 4-nitrophenyl ,- d - N, N,, N,-triacetylchitotriose and carboxy-methyl-chitin-Remazol Brilliant Violet but not towards 4-nitrophenyl N- acetyl-,- d -glucosaminide. Chitinolytic specificities of the enzymes were supported by their inactivity towards the substrates 4-nitrophenyl ,- d -cellobioside and peptidoglycan. The pH and temperature profiles for catalytic activities were relatively similar for both the enzymes. Conclusion:, The ChiA and EF0361 enzymes show a high degree of similarity in their catalytic activities although their hosts share environmental preferences only to some extent. Significance and Impact of the Study:, This study contributes to an understanding of the chitinolytic activities by L. monocytogenes and Ent. faecalis. Detailed information on their chitinolytic systems will help define potential reservoirs in the natural environment and possible transmission routes into food-manufacturing plants. [source] Emergence of a subfamily of xylanase inhibitors within glycoside hydrolase family 18FEBS JOURNAL, Issue 7 2005Anne Durand The xylanase inhibitor protein I (XIP-I), recently identified in wheat, inhibits xylanases belonging to glycoside hydrolase families 10 (GH10) and 11 (GH11). Sequence and structural similarities indicate that XIP-I is related to chitinases of family GH18, despite its lack of enzymatic activity. Here we report the identification and biochemical characterization of a XIP-type inhibitor from rice. Despite its initial classification as a chitinase, the rice inhibitor does not exhibit chitinolytic activity but shows specificities towards fungal GH11 xylanases similar to that of its wheat counterpart. This, together, with an analysis of approximately 150 plant members of glycosidase family GH18 provides compelling evidence that xylanase inhibitors are largely represented in this family, and that this novel function has recently emerged based on a common scaffold. The plurifunctionality of GH18 members has major implications for genomic annotations and predicted gene function. This study provides new information which will lead to a better understanding of the biological significance of a number of GH18 ,inactivated' chitinases. [source] | ||||||||||