Chitinase production by Streptomyces sp. ANU 6277

Chitinase production by a terrestrial Streptomyces sp. ANU 6277 was studied under sub-merged fermentation. Chitinase production started after 24 h of incubation and reached maximum levels after 60 h of cultivation. A high level of chitinase activity was observed in the culture medium with pH 6 at 35ºC. Culture medium amended with 1 percent chitin was found to be suitable for maximum production of chitinase. An optimum concentration of colloidal chitin for chitinase production was determined. Studies on the influence of additional carbon and nitrogen sources on chitinase production revealed that starch and yeast extract served as good carbon and nitrogen sources to enhance chitinase yield.Chitinase was purified from crude enzyme extract by single step gel filtration by Sephadex G-100. Purified chitinase of the strain exhibited a distinct protein band near 45 kDa by means of SDS-PAGE.

Bemnisia tabaci feeding induces pathogenesis-related proteins in cassava (Manihot esculenta Crantz).

Cassava (Manihot esculenta Cranzts) plants fed upon by whitefly Bemisia tabaci showed increased levels of pathogenesis-related (PR) proteins, such as beta-1, 3-glucanase, peroxidase and chitinase activities, as compared to uninfested plants. The enzymes increased in specific activities from 2 to 7 fold and protein content in leaf extracts decreased in whitefly-infested plants, compared to uninfested plants. Among the three PR proteins, B. tabaci feeding induced significantly higher beta-1, 3-glucanase activities, when compared with other two PR proteins. Study also discussed the possible application of PR proteins in whitefly control program.

Isolation and identification of marine chitinolytic bacteria and their potential in antifungal biocontrol.

Chitinolytic marine bacterial strains (30) were isolated from the sea dumps at Bhavnagar, India. They were screened as chitinase producers on the basis of zone of clearance on chitin agar plates incorporated with calcofluor white M2R for the better resolution. Out of these, three strains namely, Pseudomonas sp., Pantoea dispersa and Enterobacter amnigenus showed high chitinase production. They were also found to produce proteases and therefore have a good potential for use as antifungal biocontrol agents for the control of fungal plant pathogens. These strains could degrade and utilize the mycelia of Macrophomina phaseoliena (Tassi) Goidanich and Fusarium sp. In vitro, these strains could inhibit the growth of Fusarium sp. and M. phaseolina. The culture filtrate inhibiting hyphal elongation was observed microscopically.

Degradation of shrimp-shell waste and production of chitinase by bacillus amyloliquefaciens under some cultural conditions

The study of chitinase production by Bacillus amyloliquefaciens grown on shrimp-shell waste as the sole carbon source showed that chitinase production with maximum enzyme activity was reached when 2% inoculum of 24 h age seed culture was used. The inoculated medium contained [g/I] shrimpshell waste, 80; NH[4]CI, 1.2: KH[2]PO [4]; K[2]HPO[4], 1.6; MgSO[4].7H[2]O, 0.1: ZnSO[4]. 7H[2]O, 0.1; ZnSO[4] .7H[2]O. FeCI[3]. 6H[2]O, 0.01; CaCI[2]2]H[2]O, 0.02 at pH 7 and the culture shaken at 30°C for 36 hours

Some factors influencing chitinase production by bacillus amyloliquefaciens

The effect of several analogues and breakdown products of chitin on the iodsetioa of the chitinase of B. amyloliquefaciens was examined. Glucose. N -acetyl-glucosamine and chitobiose inhibited the enzyme productivity. The effect of the addition of some natural extracts was also investigated and the maximum enzyme activity was produced with 2% sand extract. A simplified medium composed of 8% shrimp-shell waste and 80% sand extract yielded an enzyme of highest activity. Reaction conditions supporting best activity sum achieved using 5-7-5mg swollen chitin in 0.03 M phosphate buffer at pH 5.916.98; enzyme concentration of 11.35mg protein/reaction mixture and incubating the mixture at 45°C for 60 min

Actividad quitinolitica en extractos libres de celulas miceliales de Mucor rouxii / Chitinolytic activity in cell-free extracts from mycelial cells of Mucor rouxii

Se detectó actividad de quitinasa en el citosol, en una fracción mixta de membranas y en la fracción de paredes celulares del micelio de M. rouxii. en todos los casos, la actividad quitinolítica fué mucho más efectiva contra quitina naciente que ccontra quitina preformada. Los resultados mostraron que la pérdida en la síntesis de la quitina cuando una fracción mixta de membranas se incuba a 28-C, no se debe aun aumento en la depolimerización del polímero naciente por quitinasas endogenas. La incubación con digitonina extrajo actividad de quitinasa de las paredes celulares, pero no de la fracción mixta de membranas. No se conocen aún las implicaciones fisiológicas de la distribución de actividad de quitinasa en las diferentes fracciones subcelulares del micelo de M. rouxii