Expression and characterization of α-Amylases from penicillium citrinum with bread as growth substrate

In an attempt to enhance the industrial production of α-amylases in the tropics, sterile fresh bread was inoculated with spore suspensions of Penicillium citrinum at 25 oC. Extracellular α-amylases were produced and subjected to partial purification by ammonium sulphate precipitation and dialysis. Further purification by gel filtration and ion-exchange chromatography was engaged. The molecular weights of the α-amylase fractions obtained and estimated by gel filtration using Sephadex G-100 were approximately 56,234 Daltons, 53,089 Daltons and 11,885 Daltons. The apparent Michalis-Menten constant (Km) values for the hydrolysis of starch by the purified α-amylase fractions were approximately 8.3 mg/ml, 10 mg/ml and 7.14 mg/ml respectively. Optimum activities were at 30 oC for one of the fractions and 35 oC for the other two fractions and were at pH 5.5 and pH 6.0. The activities of the α-amylase fractions produced by the fungus were stimulated at varying degrees by NaCl, KCl, CaCl2 and MgCl2 but inhibited by Ethylene Diamine Tetraacetic Acid (EDTA), mercuric chloride (HgCl2) and 2,4-dinitrophenol (DNP). The α-amylase fractions were sensitive to heat, losing all their activities within twenty minutes of heating at 80 oC. The industrial production of α-amylases should be encouraged in the tropics using bread as a cheap source of substrate.Keywords: α-Amylase, expression, bread, purification, characterization

Amylase activity in culture filtrate of Aspergillus chevalieri

This study was carried out to determine the growth and production of amylase by Aspergilluschevalieri in a defined medium. A. chevalieri was grown in a synthetic medium containing starch as the sole carbon source. Culture filtrate exhibited amylase activity. Optimum enzyme activity was observed on the tenth day of incubation. The presence of NaCl and MgCl2 stimulated amylase activity while EDTA and HgCl2 in the reaction mixture caused a reduction in the activity of the enzyme. The activity of the enzyme was optimum at 35oC and pH 6.5. The amylase of Aspergillus chevalieri was heat labile, losing its activity completely after twenty minutes of heating at 70 oC. The amylase produced by this fungus is of significance in the brewing industry and pharmaceuticals. The observed properties would aid in preserving the enzyme and knowing optimum conditions for activity to assist in maximizing industrial output.Keywords: Amylase production, Aspergellus chevalieri, enzyme, brewing industry, pharmaceuticals

Antibiotic Resistance Profile of Bacteria isolated from Septicaemia Cases in a Tertiary Health Care in Abeokuta

ABSTRACT: The term septicaemia is often used in describing severe bacteraemic infections or a condition in which the blood serves as a site of bacteria multiplication. A total of 120 blood culture samples were collected during year 2011 to 2012. Bacteria isolated were characterized and the antibiotic sensitivity patterns were determined. The antibiotic sensitivity was carried out using Kirby-Bauer diffusion method. Bacteria isolated include Escherichia coli, Klebsiella sp, Streptococcus pneumoniae and Pseudomonas aeruginosa. The highest number of bacteria was found among patient age 10 years. Escherichia coli accounted for 12(46.2%) of the bacteria isolated while Pseudomonas aeruginosa, Klebsiella sp and Streptococcus pneumoniae accounted for 6(23.1%), 6(23.1%) and 2(7.6%) respectively. The least prevalent isolate Streptococcus pneumoniae was found only in age group 10. Ceftazidime and Levoxin showed high sensitivity rate to most of the bacterial isolates. From this study, the uncontrolled use of antibiotics may have implication for emerging resistance of bacteria to commonly -used antibiotics. [Akingbade OA, Ojo DA, Okerentugba PO, Adejuwon AO, Okonko IO

Adolescents\' Risky Sexual Behaviour and Efficacy of Psycho-Education Intervention Programme amoung Secondary School Students in Oyo State

No Abstract Available African Journal for the Psychological Study of Social Issues Vol.7(2) 2004: 205-21

Psychosocial factors associated with smoking behavior among secondary school adolescents in Ibadan Metropolis

No Abstract.African Journal for the Psychological Study of Social Issues Vol. 8(2) 2005: 264-27

Use of Tropical Strains: Aspergillus vadensis and Aspergillus oryzae as Producers of α-Amylases in Biotechnological Practice

Enzymes especially α-amylases are imported into Nigeria, West Africa in tons from the United States of America, Asia and East Europe, cumulating into annual national debts because of the dwindling exchange rate in foreign funds. There is avenue for the production of this enzyme locally in the tropics and even in the temperate zones of the world since production of this enzyme is advocated. In our study the isolates were obtained from deteriorated barley (Hordeum vulgare L.) plants grown locally in Jos, Plateau State, Nigeria. Tropical strains of Aspergillus vadensis and Aspergillus oryzae were isolated from deteriorated barley seeds placed onto potato dextrose agar slants and plates at 25o C. Sterile barley-seed medium (1% w/v) and a defined growth medium consisting MgSO4 .7H2 0, K2 HPO4 , KH2 PO4 , aspartic acid, biotin, thiamine and FeSO4 .7H2 O with a nitrogen source and a carbon source for fungal growth were inoculated with spore suspensions of approximately 5 x 106 spores per ml of one hundred and twenty-hour-old cultures of each isolate. Incubation was at 25°C. The carbon source was varied and was independently starch, maltose, sucrose, lactose, glucose or galactose when the nitrogen source was potassium nitrate. The nitrogen source was also varied and was independently ammonium chloride, urea, potassium nitrate, ammonium sulphate, glycine, sodium nitrate, tryptone or peptone, when the carbon source in the growth medium was starch. Extracellular proteins produced within a ten day incubation period were extracted and assayed for α-amylase activity using the Pfueller and Elliott (1969) method. Extracellular proteins with expression of α-amylase activities were produced by the tropical fungal strains: Aspergillus vadensis and Aspergillus oryzae grown on the barley-seed medium and the defined growth medium used in this investigation within a period of ten days at 25°C. For the production of the most active α-amylases, the best carbon sources were maltose and glucose while the best nitrogen sources were ammonium chloride and ammonium sulphate when fungal strain Aspergillus vadensis was used as an inoculum. However, the best carbon sources were barley-seed medium, starch and sucrose while the best nitrogen sources were urea, glycine and sodium nitrate when the fungal strain Aspergillus oryzae was used as an inoculum. The exploration of this innovative is an a venue for the industrial production of α-amylases. This is encouraged in tropical Nigeria, West Africa, Ukraine, and East Europe