الفهرس 
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Abstract
This study aimed to isolate and characterize the induced antibacterial gene from the bacterial-challenged adult worker of western honey bee, Apis mellifera using differential display technique. The workers were injected with gram (+ve) bacteria, Streptococcus sanguinis; gram (-ve) bacteria, Klebsiella pneumoniae and mix of both. Haemolymph challenged workers were collected for 72 hrs period post injection at 4 hrs intervals (h.p.i) as the challenged insects died after 72 h postinfection. Then protein banding patterns (Native and SDS PAGE) and antibacterial assay were investigated. The differential display technique was employed to screen the genetic variation (at RNA level) between bacterial-challenged and control Apis mellifera adult workers. Three reproducible bands were eluted and sequenced to characterize the full length cDNA of the induced gene. In addition, sequence and phylogenetic analyses of resultant gene were studied.
1-Native and SDS PAGE:
The results of native-PAGE demonstrated that there were differences in the overall protein banding pattern in the infected workers as compared to control. The results of the SDS-PAGE clarified that the molecular weight of the separated proteins ranged from 14 to 140 KDa and bacterial infection had led to the induction of different proteins as compared to control.
2- Antibacterial assay:
The bactericidal activity of haemolymph of Apis mellifera adult workers (control and treated) using agar disk-diffusion technique was estimated. The bacterial-challenged workers was tested for their antibacterial activity against gram (+ve) bacteria, S. sanguinis and gram (-ve) bacteria, K. pneumoniae based on the microbial growth inhibition zone (in mm). In control insects, the antibacterial activity of adult workers showed no inhibition effect against any of the tested bacteria after 24 and 48 hours. Meanwhile, significant antibacterial activities of the immunized haemolymph were observed against the tested gram (+ve) and gram (-ve) bacteria. Notably the antibacterial activity of the challenged samples 24 h postinfection was more than 48 h postinfection for the tested bacteria.
3- Differential display results:
Midgut samples were differentially displayed using 6 arbitrary primers at 4, 8 and 12 h postinfection with S. sanguinis, K. pneumoniae and combination of both strains. The results indicated the presence of differentially displayed bands in the bacterial-challenged workers and not observed in controls. Three reproducible bands were eluted and sequenced. The resulting sequences were blasted to lysozyme