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Document Type |
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Article In Journal |
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Document Title |
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Chitinase formation by Trichoderma harzianum isolates. كيتيناز تشكيل بواسطة harzianum الترايكوديرما المعزولة. |
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Subject |
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Chitinase formation by Trichoderma harzianum isolates. |
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Document Language |
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English |
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Abstract |
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Isolates of Trichoderma harzianum, a powerful biocontrol agent against plant pathogenic fungi, whose activity lysed Fusarium oxyspourum were found to liberate chitinase (E.C. 3.2.1.14, ,chitin glucanohydrolase),an enzyme essential for the hydrolysis of chitin, which is a major component of hyphal walls of fungi. Out of twelve isolates, only four showed high chitinolytic activity when grown on chitin containing medium. Factors involved in the production of chitinase were investigated. The enzyme was not produced in the presence of carbohydrates other than chitin, suggesting that chitinase is inducible and that chitin breakdown is regulated by a repressor-inducer mechanism. Maximum enzyme production was obtained upon using 1% chitin (w/v) in the growth medium. The chitinoytic activity was produced optimally in the medium at pH 6.5 for the four T. harzianum isolates and gradually declined as pH shifting toward acidic or alkaline side. Different nitrogen sources were tasted including pure inorgic salts, organic sources as well as some slow release nitrogen fertilizers in chitin containing media. The enzyme levels produced by the isolates T2,T3 and T5 of T. harzianum were stimulated upon using slow release nitrogen fertilizers as nitrogen sources such as ammonium thiosulfate, urea granule coated and urea + rock phosphate (NP) yielding the highest chitinase activity production . partial purification was preformed on chitinase from Trichoderma harzianum isolates by (NH4)2 SO4 precipitation achieving 1.7 , 1.6 , 1.1 and 1.24 fold from T2,T3,T5 and T9 respectively. Studies on partially purified enzyme preparations have shown that optimal activities were achieved at pH 6.6 for 60 min at 50 Celsius incubation temperature. |
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ISSN |
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1012-1319 |
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Journal Name |
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Science Journal |
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Volume |
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26 |
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Issue Number |
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1 |
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Publishing Year |
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1421 AH
2001 AD |
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Article Type |
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Article |
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Added Date |
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Wednesday, February 23, 2011 |
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Researchers
| لبنى نوار | nwara, lubna | Researcher | Doctorate | |
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