Browsing by Author "Hashem, Yomna A"

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Comparative Metabolite Profiling of Four Polyphenol Rich Morus Leaves extracts in Relation to their Antibiofilm Activity against Enterococcus faecalis
(Hindawi, 2022-07-22) Salem, Mohamed A; Salama, Maha M; Ezzat, Shahira M; Hashem, Yomna A
Enterococci are a common cause of urinary tract infections. The severity of enterococcal infections is associated with their ability to form biofilm. Morus leaves are known as a natural antibacterial, however, their antibiofilm activity against enterococcus remains unveiled. This study aimed to evaluate the ability of four polyphenol-rich Morus leaves extracts (Morus nigra, M. rubra, M. macroura, and M. alba) to inhibit biofilm formed by enterococcal clinical isolates in relation to their metabolic profiling. Results revealed that 48% of the isolates formed strong biofilm, 28% formed moderate biofilm, 20% formed weak biofilm and only 4% did not form a biofilm, the strong biofilm-forming isolates were E. faecalis and hence were chosen for this study. The antibiofilm activity of the four polyphenol-rich Morus leaves extracts revealed that the M. nigra extract exhibited the highest percentage of biofilm inhibition followed by M. rubra then M. macroura and the least inhibition was detected in M. alba, results are in accordance with the phenolic and flavonoid content of each extract. UPLC-ESI-MS/MS identified 61 polyphenolic compounds in the four extracts. Further, multivariate analysis confirmed clear segregation of M. nigra from the other species suggesting disparity in its metabolome, with accumulation of flavonoids, anthocyanidins, phenolic acids and coumarin derivatives. Quercetin and kaempferol glycosides were found to be positively and significantly correlated. In conclusion, M. nigra ethanolic extracts showed the highest phenolic content and antibiofilm activity and they could be developed as a complementary treatment for the development of antimicrobial agents.
In Silico and In Vitro Investigation of the Distribution and Expression of Key Genes in the Fucose Operon of Escherichia coli
(MDPI AG, 2023-05) Saif, Nehal A; Hashem, Yomna A; Amin, Heba M; Aziz, Ramy K
Many gut bacteria degrade polysaccharides, providing nutritional advantages to their hosts. Fucose, a mucin degradation product, was suggested as a communication molecule between the resident microbiota and external pathogens. However, the precise role and variants of the fucose utilization pathway remain to be elucidated. Here, we computationally and experimentally investigated the fucose utilization operon of E. coli. While the operon is conserved among E. coli genomes, a variant pathway, in which an ABC transporter system replaces the fucose permease gene (fucP), was computationally identified in 50 out of 1058 genomes. Comparative genomics and subsystems analysis results were confirmed by polymerase chain reaction-based screening of 40 human E. coli isolates, which indicated the conservation of fucP in 92.5% of the isolates (vs. 7.5% of its suggested alternative, yjfF). The in silico predictions were confirmed by in vitro experiments comparing the growth of E. coli strains K12, BL21, and isogenic fucose-utilization K12 mutants. Additionally, fucP and fucI transcripts were quantified in E. coli K12 and BL21, after in silico analysis of their expression in 483 public transcriptomes. In conclusion, E. coli utilizes fucose by two pathway variants, with measurable transcriptional differences. Future studies will explore this variation’s impact on signaling and virulence.