الفهرس 
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Abstract
ABSTRACT
The present work aims to identify molecular events involved in immune responses of honey bee, Apis mellifera to natural and induced infections. To achieve this task, three groups of larvae infested with Varroa destructor and two fungal species were collected as natural field infections by observing symptoms. Firstly, these two fungal infections were identified as Aspergillus niger and Aspergillus flavus both morphologically and only Aspergillus flavus via molecular identification. On the other hand, laboratory A. mellifera larvae were challenged with the Gram-positive bacteria, Streptococcus sanguinis and the Gram-negative bacteria, Klebsiella pneumoniae using micro-syringe. PCR was performed using the hemolymph and midgut samples from challenged larvae and the non-infected group using four specific primers. The results indicated the presence of bands in the challenged larvae and not observed in the control. Four reproducible bands were eluted and sequenced. The resulting sequences were blasted to Apis mellifera peptidoglycan recognition protein-LC, relish, defensin, and prophenoloxidase genes. The expression levels of each gene were estimated from the control group and infected larvae either laboratory or field infections using qPCR analysis. The results indicated the different up-regulation of these immune-related genes in the hemolymph samples of field infections, but down-regulated at Varroa infestation in the midgut samples. On the other hand, after bacterial challenge at 6, 12, and 24 hrs post injection, the levels of all tested genes in the hemolymph and midgut altered dramatically. Finally, the midgut microbiome of uninfested and infested honey bee larval (last instar) and adults of workers with V. destructor were investigated using a culture-dependent isolation along with 1