Effects of Bacillus thuringiensis kurstaki on the cells of Malpighian tubule of the Thaumetopoea pityocampa (Lepideptera:Thaumetopoeidae) larvae

Ill EFFECTS OF BACILLUS THURINGIENSIS KURSTAKİ ON THE CELLS OF MALPIGHIAN TUBULE OF THE THAUMETOPOEA PITYOCAMPA (LEPDDOPTERA: THAUMETOPOEIDAE) LARVAE M. Sc. Thesis Ayşe Ö?ÜTÇÜ GAZI UNIVERSITY INSTITUTE OF SCIENCE AND TECHNOLOGY June 2002 ABSTRACT In this study, the effects of Bacillus thuringiensis var. kurstaki, a microbial insecticide, on Malpighian tubule cells of Thaumetopoea pityocampa (Lepidoptera: Thaumetopoeidae) larvae was studied under electron microscope. Fourth instar larvae foods are sprayed with 3 x 108 bacteria/ml. 1, 3, 6, 12, 24, 48, 60 hr and 4 days after bacterial treatment, Malpighian tubule cells of T. pityocampa larvae were studied under transmission electron microscope as compared with that of control group. 1, and 3 hr after bacterial treatment, no differences was detected in the structure of Malpighi tubule cells when compared to control group. Swelling in microvilli of Malpighi tubule cells and swelling in mitochondria were noticed at 6 and 12 hr after treatment, respectively. Melting in nucleoplasm and basal membrane infolding, and swelling in mitochondria of Malpighi tubule cells and breakage in their cristae were considerably noticable 24 hr after bacterial treatment. Microvillus of Malpighi tubule cells was found to be shorten and vacuoles in the cytoplasm were found to be formed at 48 and 60 hr after bacterial treatment. Degeneration in mitochondria and an increase in the number of autophagic vacuoles in the Hi-'-'IV mitochondria in microvilli of the cells and formation of numerous vacuoles in the cytoplasm were detected. Approximately 5 days after treatment, most of the larvae were found to be death. Science Code :405. 01. 06 KeyWords iThaumetopoea pityocampa, Malpighian tubules, Microbial insecticides, Bacillus thuringiensis kurstaki, infrastructure, Electron microscope Page Number :59 Adviser :Prof. Dr. Zekiye SULUDERE