Browsing by Author "Mohiuddin, Sayed G."
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Item Evolution of Resistant Mutants in Antibiotic Treated Bacterial Cultures(2019) Figueroa, Diego A.; Mohiuddin, Sayed G.Bacterial Persisters are cells who undergo a phenotypic shift and enter a dormant state in order to tolerate new levels of stress. Persisters are present in every colony of bacteria and can cause chronic infections. Even when treatment is successful in killing bacteria and removing the patient’s symptoms, the persisters will eventually resuscitate and proliferate a new colony. Preliminary experiments done by my mentor suggested that Ofloxacin, a quinolone that affects cell replication and induces the cells DNA repair mechanisms, can cause random mutations in the genomic DNA of bacteria. My goal of this investigation was to enrich Escherichia coli cultures with antibiotic resistant mutants, for cross analysis with a parental strain and a Green Fluorescent Protein (GFP) producing strain. The purpose of this is to figure out if persisters are more important than resistant mutants. Our data demonstrates that persister cells do function as a reservoir for resistant mutants because of the increased survivors. This poses as a threat because some of the mutants were even able to withstand antibiotic treatment of ampicillin and gentamicin. In conclusion, these results suggest that novel anti-persister treatment will help with the battle against antibiotic resistance.Item Targeting DNA Repair Mechanisms in Bacterial Persisters(2019) Oviedo, Cristian; Bolanos, Maria; Mohiuddin, Sayed G.; Saba, AdesolaBacterial persisters, cells able to survive high concentrations of antimicrobial agents, are problematic in the medical field due to being responsible for recurring infections, and in industrial settings due to causing contamination in pipes. Furthermore, bacterial biofilms add complexity due to being more enduring than stand alone planktonic bacteria. The inability to successfully eradicate persisters present in patients with recurring bacterial infections and from industrial pipes has prompted interest in targeting persisters through metabolomics. Moreover, interest has expressed in determining the distribution of persisters in biofilms, if any, and why persisters would be more localized in one area than in another. Targeting the DNA repair mechanisms of bacteria, and mapping persister distribution in biofilms are of much interest. The expression of RecA, a protein essential for catalyzing the SOS response for damaged DNA, was targeted in wild type E.coli in order to create RecA lacking E.coli mutants. The mutants were then treated with ofloxacin, a fluroquinolone that causes DNA damage, in order to examine the effects of inhibiting the SOS response. Separately, wild type E.coli biofilms were grown and subsequently sectioned into different categories, with the determining factor being color, to then be treated with antibiotics in order to determine the distribution of persisters. The implications of this study show that targeting DNA repair mechanisms in bacteria can lead to a significant reduction of persisters, as well as that persisters in biofilms are not localized in some areas more than others despite differences in color.