Partial Purification ofPolygalacturonase from Tomato Fruits Infected by Rhizopus arrhizus Fisher

The production of polygalacturonase during the deterioration of tomato (Lycopersicon esculentum Mill.) by Rhizopus arrhizus Fisher was investigated. The enzyme was partially purified by a combination of ammonium sulphate precipitation, gel filtration and ion-exchange chromatography. Two peaks of absorption, with molecular weight estimates of approximately 166 000 Daltons and 60 260 Daltons were obtained

Antibiotics resistance of a strain of Escherichia coli isolated from bore hole in Ile Ife, Osun state, Nigeria

Abstract:Escherichia coli were isolated from water from two boreholes in Ile Ife, Osun state, Nigeria. This was an indication of faecal contamination. These strains of Escherichia coli were Gram negative short rods, Catalase positive, Methyl red positive, Voges Proskaeur negative. The strains could ferment glucose galactose, sucrose, lactose, mannitol and maltose with the production of acid and gas but could not hydrolyze starch. A particular strain was resistant to sulfamethoxazole, ampicillin, cotrimoxazole, cephaloridine, streptomycin, carbenicillin, sulfafurazole and tetracycline but sensitive to gentamicin, colistin, nalidixic acid, nitrofurantoin and colistin sulphat

Cellulase activity in tomato fruits infected with Penicillium funiculosum Thom.

Within eight days of incubation at room temperature (27°C), tomato (Lycopersicon esculentum Mill.) fruits infected with Penicillium funiculosum Thom. had deteriorated. Extracts from the infected fruits exhibited cellulase activity. Uninfected fruits lacked cellulase activity. The enzyme was partially purified by a combination of gel filtration and ion-exchange chromatography. On separation by molecular exclusion chromatography, two peaks of absorption with molecular weight estimates of 223,800 Daltons and 89,100 Daltons were obtained. Only the components of the peak with the lighter weight exhibited cellulase activity. The enzyme showed optimum activity at pH 4.5 and 40°C. Na+ and Ca++ ions stimulated enzyme activity while EDTA and Hg++ were inhibitory. The apparent km for the hydrolysis of carboxymethylcellulose was approximately 0.53 mgml-1. The occurrence of cellulase in tomato fruits infected with P. funiculosum Thom. and its absence in uninfected fruits suggests a role of this enzyme in pathogenicity of the fungus. Cellulolytic components of the fruits are degraded, the fruits are deteriorated and lost to this post harvest pathogen. Knowledge of the conditions of growth of this fungus and properties of this enzyme will assist the farmer in optimizing production of these fruits and engaging the best conditions for preservation

Purification of Cellulase obtained from Tomato fruits (Lycopersicon lycopersicum (L.) Karst) deteriorated by Aspergillus Flavus Linn.

Tomato fruits infected by Aspergillus flavus Linn produced proteins with cellulolytic activity. The enzyme was partially purified by Ammonium Sulphate Precipitation, Gel filtration and ionexchange chromatography. Three peaks of absorption A, B and C were obtained. Peak B had Cellulase activity with molecular weight of approximately 30,200 Daltons while Peaks A and C lacked Cellulase activity. Elution of components of Peak B on CM Sephadex C-25 produced four peaks of absorption designated Ba, Bb, Bc and Bd. Only components of Peaks Bb and Bc possessed Cellulase activity. Purification folds of approximately 80 and 81 were obtained for components of Peaks Bb and Bc respectively for Cellulase of A. flavus. The apparent Km values for the hydrolysis of carboxymethylcellulose by A.flavus Cellulase fractions, Bb and Bc were approximately 16.7 and 15.4mg/ml respectively. The partially purified enzyme preparations obtained from A.flavus during the deterioration of tomato fruits caused tissue maceration and cellular death. This result can be very useful in splitting and solubilization of pectic substances and pathogenicity