| Publications |
| Journal of Egyptian Academic Society for Environmental Development (A entomology). 2(1): 95-115. Egypt. 2002. Changes in the haemolymph of the desert locust, Schistocerca gregaria after injection with Bacillus thuringiensis Emad M. S. Barakat 1; Wesam S. Meshrif 2 and Magdi G. Shehata 1 Department of Entomology, Faculty of Science, Ain Shams Univ., Abassia, Cairo, Egypt Department of Zoology, Faculty of Science, Tanta Univ., Tanta, Egypt ABSTRACT Variable changes in the haemolymph volume, density and pH of the desert locust, Schistocerca gregaria (Forskal) were recorded at different time intervals post-injection with the bacterium, Bacillus thuringensis kurstaki Berliner into the haemocoel. At the same time changes in the total and differential haemocyte counts were investigated. Also, several pathological consequences were observed in the haemocytes (plasmatocytes, coagulocytes and granulocytes)including variation in the cell volume, vacuolization in the cytoplasm, distortion of the cell membrane and pycnosis in the nuclei. Key words: Schistocerca gregaria, Bacillus thuringensis, haemolymph and haemocytes. J. Egypt. Acad. Soc. Environ. Develop. (A entomol.). 2(1): 117-130. Egypt. 2002. Cell-mediated immunity in the desert locust, Schistocerca gregaria against the bacterium, Bacillus thuringiensis Wesam S. Meshrif 2 and Emad M. S. Barakat 1 Department of Entomology, Faculty of Science, Ain Shams Univ., Abassia, Cairo, Egypt Department of Zoology, Faculty of Science, Tanta Univ., Tanta, Egypt ABSTRACT Cellular defense mechanisms, phagocytosis and nodule formation of the fifth nymphal instar and adult Schistocerca gregaria (Forskal) were studied following injection with the bacterium, Bacillus thuringensis kurstaki Berliner into the haemocoel. Phagocytosis was shown to be composed of four phases: attachment; signal trasnduction, pseudopodial activation and actual engulfment. Plasmatocytes were the essential phagocytic cell type. The peak of the phagocytic activity was at 6 hr post-injection in both insect stages, but it was higher in adults than in the fifth nymphal instar. Nodule formation involves the proliferation, aggregation and adhesion of numerous haemocytes around parasites, which are not phagocytosed. A significant increase in nodule counts at all time intervals post-injection was observed above controls. The peak of nodule formation was 12 hr post-injection in both stages. However, the nodule count was higher in the fifth instar than in adults. Key words: Schistocerca gregaria, Bacillus thuringensis, cellular immunity, phagocytosis and nodule formation. J. Egypt. Acad. Soc. Environ. Develop. (A entomol.). 2(1): 131-149. Egypt. 2002. Antibacterial activity and analysis of haemolymph proteins of the desert locust, Schistocerca gregaria following injection with Bacillus thuringiensis Emad M. S. Barakat 1; Wesam S. Meshrif 2 ; Magdi G. Shehata 1 and Amal I. Seif 2 Department of Entomology, Faculty of Science, Ain Shams Univ., Abassia, Cairo, Egypt Department of Zoology, Faculty of Science, Tanta Univ., Tanta, Egypt ABSTRACT Fifith nympal instar and adult of the desert locust, Schistocerca gregaria (Forskal) were studied in order to detect the induction of antibacterial activity in the haemolymph following injection with the bacterium, Bacillus thuringensis kurstaki Berliner. A slight activity was demonstrated in normal locust plasma, while a significant increase of this activity appeared in both control and immune plasma, when tested by the agar-well diffusion method. The maximum activity attained 24 hr post-injection in both insect stages. Analysis of the plasma proteins by SDS-polyacrylamide gel electrophoresis showed the disappearance of some proteins and appearance of other new immune proteins in the injected fifth nymphal instar and adult stages due to the induction of injected bactreria. Some of these new proteins may function in the immune response. Key words: Schistocerca gregaria, Bacillus thuringensis, antibacterial activity, haemolymph proteins and electrophoresis. |
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