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.

Degradation of fungal cell walls of phytopathogenic fungi by lytic enzyme of Streptomyces griseus.

Abstract: In vitro tests of interactions between Streptomyces griseus strains and some soil-borne plant pathogens (Fusarium oxysporum, Alternaria alternate, Rhizoctonia solani and Fusarium solani) and 2 isolates of Aspergillus flavus were studied on PDA medium. Strains tested produced a metabolite that inhibited growth of plant pathogenic fungi on PDA medium (dual culture test). When grown in liquid medium having fungal cell walls as sole carbon source, S. griseus produced chitinase enzyme in the medium. Higher levels of this enzyme were induced by cell wall ofAspergillus flavus and the crude chitinase enzyme extracted showed zone of inhibition on all pathogens inoculated PDA plates at all tested concentrations. When lytic enzyme produced by S. griseus was incubated with hyphal wall of the test fungi treated with 2 M NaOH and chloropharm: Methanol, the release of glucose and N acetyl glucosamine significantly increased relative to the untreated one. This result suggests that proteins in the cell walls of pathogens may make these walls more resistant to degradation by the extracellular lytic enzymes. Ionic strength of NaOH on lytic activity was tested, where as the enzymes lysed fungal cell wall best at ionic concentration of 2 M treatment. Pretreatment with alkali or proteolytic enzyme increases their susceptibility for lysis. In vitro lytic activity provides an appropriate condition and the effect of biocontrol organism in field level treatment. Key words: Chitinase enzyme, dual culture test, plant pathogenic fungi, NaOH treatment and Ionic strength.

Foliar application of Bacillus subtilis AUBS1 reduces sheath blight and triggers defense mechanisms in rice

Abstract: Foliar application of Bacillus subtilis strain AUBS1 significantly reduced the sheath blight disease of rice (Oryza sativa L.) under greenhouse conditions. Treatment with B. subtilis led to an increase in the activities of phenylalanine ammonia-lyase (PAL) and peroxidase (PO) and an accumulation of pathogenesis-related (PR) proteins in rice leaves. Application of B. subtilis also induced an accumulation of a thaumatin-like protein (17 kDa) and two s-1-3-glucanases (30 kDa and 33 kDa). Western blotting analysis for chitinase revealed the induction of two chitinases with apparent molecular masses of 30 kDa and 35 kDa in the induced plants. The coordinate upregulation of different defense mechanisms in induced plants suggests that these defense responses may be involved in the restriction of Rhizoctonia solani.

Inhibition of Candida albicans morphogenesis by chitinase from Lactobacillus rhamnosus GG

Abstract: Lactobacilli have been evaluated as probiotics against Candida infections in several clinical trials, but with variable results. Predicting and understanding the clinical efficacy of Lactobacillus strains is hampered by an overall lack of insights into their modes of action. In this study, we aimed to unravel molecular mechanisms underlying the inhibitory effects of lactobacilli on hyphal morphogenesis, which is a crucial step in C. albicans virulence. Based on a screening of different Lactobacillus strains, we found that the closely related taxa L. rhamnosus, L. casei and L. paracasei showed stronger activity against Candida hyphae formation compared to other Lactobacillus species tested. By exploring the activity of purified compounds and mutants of the model strain L. rhamnosus GG, the major peptidoglycan hydrolase Msp1, conserved in the three closely related taxa, was identified as a key effector molecule. We could show that this activity of Msp1 was due to its ability to break down chitin, the main polymer in the hyphal cell wall of C. albicans. This identification of a Lactobacillus-specific protein with chitinase activity having anti-hyphal activity will assist in better strain selection and improved application in future clinical trials for Lactobacillus-based Candida-management strategies.

Expression and characterization of endochitinase C from Serratia marcescens BJL200 and its purification by a one-step general chitinase purification method.

Abstract: In this study we cloned, expressed, purified, and charaterized chitinase C1 from Serratia marcescens strain BJL200. As expected, the BJL200-ChiC1 amino acid sequence of this strain was highly similar to sequences of ChiC1 identified in two other strains of S. marcescens. BJL200-ChiC1 was overproduced in E. coli by the T7 expression system, and purified by a one-step hydrophobic interaction chromatography (HIC) with phenyl-sepharose. BJL200-ChiA and BJL200-ChiB had an approximately 30-fold higher k(cat) and 15 fold-lower K(m) than BJL200-ChiC1 for the oligomeric substrate 4-methylumbelliferyl-beta-D-N-N'-N''-triacetylchitotrioside, while BJL200-ChiC1 was 10-15 times faster than BJL200-ChiB and BJL200-ChiA in degrading the polymeric substrate CM-chitin-RBV. BJL200-ChiC1 degradation of beta-chitin resulted in a range of different chito-oligosaccharides (GlcNAc)(2) (main product), GlcNAc, (GlcNAc)(3), (GlcNAc)(4), and (GlcNAc)(5), indicating endo activity. The purification method used for BJL200-ChiC1 in this study is generally applicable to family 18 chitinases and their mutants, including inactive mutants, some of which tend to bind almost irreversibly to chitin columns. The high specificity of the interaction with the (non-chitinous) column material is mediated by aromatic residues that occur in the substrate-binding clefts and surfaces of the enzymes.