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.

Cloning and Expression of Two Chitin Deacetylase Genes of Saccharomyces cerevisiae

Abstract: Chitin deacetylase (EC 3.5.1.41), which hydrolyses the N-acetamido groups of N-acetyl-D-glucosamine residues in chitin, has been demonstrated in crude extracts from sporulating Saccharomyces cerevisiae. Two S. cerevisiae open reading frames (ORFs), identified by the Yeast Genome Project, have protein sequence homology to a chitin deacetylase from Mucor rouxii. Northern blot hybridizations show each ORF was transcribed in diploid cells after transfer to sporulation medium and prior to formation of asci. Each ORF was cloned in a vector under transcriptional control of the GAL 1, 10 promoter and introduced back into haploid strains of S. cerevisiae. Chitin deacetylase activity was detected by in vitro assays from vegetative cells grown in galactose. Chemical analysis of these cells also demonstrated the synthesis of chitosam in vivo. Both recombinant chitin deacetylases showed similar qualitative and quantitative activities toward chitooligosaccharides in vitro. A diploid strain deleted to both ORFs, when sporulated, did not show deacetylase activity. The mutant spores were hypersensitive to lytic enzymes (Glusulase or Zymolyase).

An acidic, thermostable exochitinase with β-N-acetylglucosaminidase activity from Paenibacillus barengoltzii converting chitin to N-acetyl glucosamine.

Abstract: Background N-acetyl-β-D-glucosamine (GlcNAc) is widely used as a valuable pharmacological agent and a functional food additive. The traditional chemical process for GlcNAc production has some problems such as high production cost, low yield, and acidic pollution. Hence, to identify a novel chitinase that is suitable for bioconversion of chitin to GlcNAc is of great value.

Antagonism of Trichoderma spp. against Macrophomina phaseolina: Evaluation of Coiling and Cell Wall Degrading Enzymatic Activities

Abstract: In vitro potentialities of seven species of Trichoderma were evaluated against phytopathogen Macrophomina phaseolina by dual culture techniques. The maximum growth inhibition of test pathogen was observed by antagonist T. koningi MTCC 796 (T4) (74.3%) followed by T. harzianum NABII Th 1 (T1) (61.4%) at 7 days after inoculation (DAI). Further, mycoparasitism of antagonists were observed upto 14 DAI. Pattern of growth inhibition of test fungus was continued with maximum 14.7% increases in T4 (85.2%) followed by 6.8% elevation in T1 (65.6%) antagonists during 7 to 14 DAI. Microscopic study showed that these two antagonists were capable of overgrowing and degrading M. phaseolina mycelia, coiling around the hyphae with apressoria and hook-like structures. At 14 DAI, T. koningi MTCC 796 completely destroyed the host and sporulated. The specific activities of cell wall degrading enzymes- chitinase, β-1, 3 glucanase, protease and cellulase were tested during different incubation period (24, 48, 72 and 96 h) when Trichoderma spp. grew in presence of pathogen cell wall in synthetic media. The antagonist T. koningi MTCC 796 induced higher chitinase and protease activity at 24 h incubation while β-1, 3 glucanase activities was elevated 1.18 fold during 72 to 96 h. Total phenol was produced significantly higher in culture supernatant of T. koningi MTCC 796 antagonist followed by T. hamatum NBAII Tha 1 and T. harzianum NBAII Th 1 at 48 h incubation. The growth inhibitions of pathogen during antagonism was positively correlated with coiling pattern of antagonists at 14 DAI, and induction of chitinase, β-1, 3 glucanase and total phenol content.

Biocontrol of wood-rotting fungi with Streptomyces violaceusniger XL-2.

Abstract: During the previous decade, chitinases have received increased attention because of their wide range of applications. Chito-oligomers produced by enzymatic hydrolysis of chitin have been of interest in recent years because of their broad applications in medical, agricultural, and industrial applications, such as antibacterial, antifungal, hypo cholesterolemic, and antihypertensive activity, and as food quality enhancer. Fungal cell walls being rich in chitin also enable the use of chitinases in biocontrol of fungal pathogens, as bio-fungicides. An actinomycete was isolated from the bark of trees of Dehradun in India and was later identified as Streptomyces violaceusniger. This strain exhibits strong antagonism towards various wood-rotting fungi, such as Phanerochaete chrysosporium, Postia placenta, Coriolus versicolor, and Gloeophyllum trabeum. Further, studies showed an extracellular bioactive compound was responsible for the antagonism. The conditions for the production of this biocontrol agent were optimized, and the effects of various stress factors (like nitrogen-deficient media, carbon-deficient media, etc.) were studied. The presence of chitin in the growth media was found to be an essential factor for the active production of the biocontrol agent. The pH and temperature optima for the biocontrol agent were determined. Purification and characterization of this specific biocontrol agent was performed through anion exchange chromatography using a DEAE-cellulose column, and a single protein band was obtained on a 10% sodium dodecyl sulfate-polyacrylamide gel. The protein was later identified as a 28 kDa endo chitinase by MALDI-TOF (matrix-assisted laser desorption ionization-time of flight) and by a chitobiose activity assay.