M.Sc. Tezi Görüntüleme | |||||||||||||||||||||
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| Summary: Bacillus thuringiensis is a gram-positive, facultative anaerob soil bacterium can be sporulated. During sporulation, it produces different δ-endotoxins that have a parasporal crystal structure because of the B. thuringiensis, an important insect pathogen, is effectively and widely used in combating pests. Because of their potential, B. thuringiensis is the most produced and most marketed commercial microbial control preparate around the world today. B. thuringiensis MnD isolate used in this study was isolated from a naturally dead M. neustria larvae. cry2Ab gene belonging to that isolate was amplified with the PCR method by using degenerate primers. The amplified gene was cloned to pGEM-T Easy Vector and its sequence analysis was performed in order to identify the nucleotide sequence. DNA and aminoacid sequence of cry2Ab gene that underwent a sequence analysis, was compared with the DNA and aminoacid sequences of existent cry2Ab gene in literature.The results of anaysis show that cry2Ab gene belonging to the local B. thuringiensis isolates used in this study has a length of 1902 bp and 633 aminoacid sequence. Besides, it has %99 homology with the cry2Ab gene of B. thuringiensis ly30 bacterium in literature. The sequenced cry2Ab gene was cloned to the pET-28a(+) expression vector and their proteins were expressed in Escherichia coli. The result was exposed to SDS-PAGE analysis and it was found that cry2Ab protein had the size of 70 kDa. The insecticidal activity of the cry2Ab protein produced was tested on Malacosoma neustria L. (Diptera: Lasiocampidae) and Rhagoletis cerasi L. (Diptera: Tephritidae). It was found that cry2Ab protein in 100 μg concentration showed 73% insecticidal effect on M. neustria larvae and 75% insecticidal effect on R. cerasi larvae. Keywords: Bacillus thuringiensis, cry2Ab Gene, Crystal Proteins, Insecticidal Activity | |||||||||||||||||||||