Study of antimicrobial activities of chitinases from a potato prototype cultivated in Bangladesh

Chitinases (designated as SPCs) were isolated from „Shilbilati‟ potatoes, a potato prototype cultivated in Bangladesh by affinity chromatography on a chitin column. SPCs agglutinated rat erythrocytes at the minimum concentration of 7 μg/mL and showed toxicity against brine shrimp nauplii with the LC50 value of 20 μg/mL. The chitinases also agglutinated seven bacterial strains among the twelve as studied. Pseudomonas aeruginosa, Bacillus subtilis and Salmonella typhi were the most sensitive towards the SPCs and were agglutinated at 1.2, 2.5 and 5.0 μg/mL protein concentrations respectively. Antibacterial tests demonstrated that SPCs showed inhibitory activity against the pathogenic bacteria Staphylococcus aureus, Bacillus subtilis and Salmonella typhi. Antifungal activity was investigated by the disc diffusion method. Five fungal species (Candida albicans, Aspergillus niger, Fusarium vasinfectum, Aspergillus fumigatus and Aspergillus flavus) and two fungal genus (Penicillium and Mucor sp.) were examined in the assay. SPCs showed antifungal activity against Candida albicans, Fusarium vasinfectum and Penicillium sp.

Purification and Characterization of Intracellular Cellulase from Aspergillus oryzae ITCC-4857.01

Purification and characterization of intracellular cellulase produced by A. oryzae ITCC-4857.01 are reported. The enzyme was purified by ion-exchange chromatography using DEAE-cellulose followed by Gel filtration. The purification achieved was 41 fold from the crude extract with yield of 27%. The purified enzyme showed single band on poly acrylamide gel. The molecular weight as determined by SDS-PAGE and gel filtration was 38 KDa and 38.6 KDa respectively and contained only one subunit. The enzyme is glycoprotien as nature and contained 0.67% neutral sugar. The apparent Km value of the enzyme against cellulose was 0.83%. The enzyme showed the highest relative ativities on CMC followed by avicel, salicin and filter paper. The optimum pH of activity was 5.5 and very slight activity was observed at or above pH 7.5 as well as bellow pH 3.5. The optimum tempreture of the activity was 45degrees C and the highest activity was exhibited in 35 to 45degrees C. The enzyme lost their activities almost completely (95~100%) at 80 degrees C or above and as well as bellow 25degrees C.

Study of toxicity and haemagglutinating activitiy of a purified intracellular toxin and extracellular crude toxin isolated from pseudomonas aeruginosa

The action of purified intracellular toxin [PIT] from Pseudomonas aeruginosa was examined in brine shrimp lethality bioassay. The LC50 of the PIT was calculated to be 25 microg/ml. The PIT agglutinated both albino rat and rabbit erythrocytes more potently than did extracellular crude toxin [ECT]. Galactose and Dmannose, however inhibited the agglutination property of PIT and ECT respectively. Intradermal injection of PIT caused changes on the tissues of rabbit skin at a lower dose than that of ECT

Characterization of an intracellular protease from pseudomonas aeruginosa

An intracellular protease was extracted and purified from Pseudomonas aeruginosa by ion-exchange chromatography on DEAE-cellulose followed by CM"cellulose and rechromatography on DEAE-cellulose. The purified protease was found to be homogeneous as judged by polyacrylamide disc gel electrophoresis [PAGE]. The molecular mass of the protease as determined by gel filtration on G-150 was about 48,000 and about 49,000 on SDS-PAGE. The enzyme is monomeric in nature. The purified protease is a glycoprotein with neutral sugar content of 0.6%. The Km value of the protease was found to be 0.48% against casein as substrate. The enzyme is stable up to 600C and showed maximum activity around 500C. The enzyme activity was affected with the changes of pH and the maximum proteolytic activity was observed at pH 8.0. The protease activity was inhibited in the presence of EDTA, Cu2+, Mn2+and Hg2+ whereas the presence of Ca2+, K+, Na+ and ascorbic acid enhanced the activity