5141
Shimaa Mahmoud Abdel-HamidSalem Ghazal
Genetic Improvement of Insect- Pathogenic Photorhabdus Bacteria
fosmid cloncs,photorha bclus, transposable elements. 4v- trridrahon. droft, genone seguance
The bacterium Photorhabdus luminescens is mutualistically associated with entomopathogenic nematodes. These nematodes invade insect larvae and release the bacteria from their intestine, which kills the insects through the action of toxin complexes and other extracellular enzymes. In this study, a draft genome sequence for the local isolate BA1 has been achieved along with an identification of some virulence genes. From nine P. luminescens strains, four locally isolated in Egypt and five strains adapted in the Egyptian environment, were tested for exoenzymes and antimicrobial. Two P. luminescens strains (BA1, a local isolate, and Hb, an adapted strain) were treated with UV irradiation and resulting 170 and 120 mutants from Hb and BA1, respectively, were screened for overproduction of exoenzymes (lipases, proteases, chitinase and lecithinase) and antimicrobial activity. Strain BA1 subjected to intensive studies on the bioinformatics and the molecular levels. On the bioinformatics level; draft genome sequence for BA1 followed by detailed genomic analysis and comparative studies among BA1 genome and other Photorhabdus strains from species luminescence and temperata. On the molecular level a transposon mutant library were built composed of more than 2000 mutants of BA1, were studied for their lipases and proteases production, antimicrobial activity and their motilityas well, with the effect of each selected mutant on the pathogenesis and infection of Galleria mellonella. Also, a fosmid library of over 560 clones was screened for hemolysin genes and its effect on the pathogenesis and infection of Galleria mellonella
2016
Ph.d
Ain Shams
Science