National University Biomedical Research Institute (NUBRI)
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Item Green synthesis of silver nanoparticles using Sudanese Candida parapsilosis: a sustainable approach to combat antimicrobial resistance(BMC Microbiology, 2025) Ibrahim, Nesreen A. A.; Saeed, Humodi A.; Saeed, Samar M.; Mohamed, Osama; Suliman, Omnia H.; Ibrahim, Sabah A. E.; Mohamed, Sofia BBackground Antimicrobial resistance (AMR) is a critical global health challenge, particularly in Sudan, where the overuse and misuse of antibiotics have driven the rise of multidrug-resistant (MDR) pathogens. Conventional antimicrobial strategies often fall short due to rapid resistance development and limited efficacy, highlighting the need for novel approaches. Nanotechnology offers promising alternatives, with silver nanoparticles (AgNPs) demonstrating potent broad-spectrum antimicrobial activity. This study aims to develop an eco-friendly synthesis of AgNPs using Candida parapsilosis (C. parapsilosis), an untapped yeast strain isolated from Sudanese soil, to combat AMR. Results Biosynthesis of AgNPs using C. parapsilosis was successfully confirmed through UV-Vis spectroscopy, X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM), revealing well-defined nanoparticles. The biosynthesized AgNPs exhibited strong antibacterial activity against both ATCC reference strains and MDR clinical isolates of Gram-positive and Gram-negative bacteria, with inhibition zones increasing in a concentration-dependent manner. At optimal concentrations, inhibition zones reached 29 mm for Pseudomonas aeruginosa (P.aeruginosa) (ATCC 27853), while clinical isolates of Salmonella typhi (S. typhi) (24.5 ± 0.58 mm) and Escherichia coli (E. coli) (23.8 ± 0.79 mm) exhibited significant susceptibility. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays demonstrated potent bactericidal activity, particularly against E. coli and Klebsiella pneumoniae (K. pneumoniae) at 0.3125 mg/mL. Furthermore, AgNPs synergistically enhanced the efficacy of conventional antibiotics in a species- and antibiotic-dependent manner. The strongest synergy was observed in Enterococcus faecalis (E. faecalis) (up to 9.84-fold with Colistin) and Acinetobacter baumannii (A. baumannii) (up to 5.11-fold with Ceftazidime), suggesting that AgNP-enhanced antibiotic efficacy varies depending on bacterial species, nanoparticle synthesis method, and antibiotic type. Conclusions This study presents a novel and sustainable approach to tackling AMR by leveraging Sudanese yeast strains for the green synthesis of AgNPs. The findings underscore the potential of AgNPs as an effective antibacterial agent, both independently and in combination with conventional antibiotics, to combat MDR pathogens. By integrating microbiology and nanotechnology, this research offers a cost-effective and environmentally friendlyItem The impact of mutations on TP53 protein and MicroRNA expression in HNSCC: Novel insights for diagnostic and therapeutic strategies(PLOS One, 2025) Mahmoud, Ashraf Attia; Raih, Mohd Firdaus; Sage, Edison Eukun; Ali, Qurashi M.; Suliman, Omnia H.; Ibrahim, Sabah A. E.; Mohamed, Osama; Abdelrazeg, Samar; Mohamed, Sofia B.The tumor suppressor protein p53 (TP53) is frequently mutated in various types of human malignancies, including HNSCC, which affects tumor growth, prognosis, and treatment. Gaining insight into the impact of TP53 mutations in HNSCC is crucial for developing new diagnostic and therapeutic methods. In this study, we aimed to investi gate the influence of mutations on the structure and functions of the TP53 protein and miRNA expression using computational analysis. The genomic data of patients with HNSCC were obtained from TCGA, and the impact of mutations on the TP53 gene was investigated using different bioinformatics tools. Results: The findings showed that the TP53 mutations increased TP53 expression levels in HNSCC and were associated with a poor prognosis. Furthermore, hsa-mir-133b expression was reduced in TP53- mutated samples, significantly affecting patient survival in HNSCC. Six mutations, including R273C, G105C, G266E, Q136H/P, and R280G, were identified as delete rious, carcinogenic, driver, highly conserved, and exposed. These mutations were located in the P53 domain, and PTM analysis revealed that R280G and R273C are at a methylation site, and R273C, Q136H/P, and R280G are located in the protein pocket. The docking research indicated that these mutations decreased the binding affinity for DNA, with R273C, R280G, G266E, and G105C displaying the most significant differ ences. The molecular dynamics analysis indicates that R280G, Q136H, and G105C mutations confer a gain of function by stabilizing the TP53-substrate complex. Conclu sions: Based on the research findings, the mutations on TP53 were found to have an impact on protein and miRNA expression, development, survival, and progression of HNSCC patients, and has-mir-133b could be a promising novel biomarker for mon itoring the progression of HNSCC. It was discovered that G105C and Q136H/P, as novel mutations, affect the function and structure of proteins causing HNSCC, which indicates that they could be interesting subjects for further investigation, diagnostics, and therapeutic strategies. Furthermore, the precise positioning of R280G and R273C within the methylation site and Q136H/P in the binding site has been documented for the first time. Moreover, the G105C, Q136H, and R280G mutations that stabi lized TP53 structure and altered its interaction dynamics with substrates may serve as novel potential diagnostic biomarkers in cancer, guiding patient stratification and personalized treatment strategies. The molecular dynamics analysis provides insights into how specific TP53 mutations impact protein structure, stability, and function upon substrate binding, highlighting their role in cancer biology and potential implications for therapeutic interventions. This paper provides a novel understanding of the mecha nisms by which these mutations contribute to the development of cancer.