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EFFECT OF METABOLIC INHIBITION ON THE GROWTH AND BIOFILM PRODUCTION OF VIBRIO CHOLERAE AND PSEUDOMONAS AERUGINOSA
Title
EFFECT OF METABOLIC INHIBITION ON THE GROWTH AND BIOFILM PRODUCTION OF VIBRIO CHOLERAE AND PSEUDOMONAS AERUGINOSA
Creator
Bunn, Dakota C.
Date
2017, 2017-05
Description
V. cholerae is a gastrointestinal pathogen which causes extreme watery diarrhea and results in over 120,000 deaths per year worldwide. It is...
Show moreV. cholerae is a gastrointestinal pathogen which causes extreme watery diarrhea and results in over 120,000 deaths per year worldwide. It is especially prevalent in developing countries that lack proper water treatment and in areas struck by natural disasters such as hurricanes. P. aeruginosa is an opportunistic pathogen that is ubiquitous in nature, and increasingly found in hospitals burn wards, sinks, catheters and other surgical equipment. Both bacteria are developing increased antibiotic resistance through several mechanisms, with one of the most common ones being the formation of a complex exopolysaccharide matrix known as a biofilm. In this study, using metabolic inhibition, we determined that Na+-NQR is essential for the growth of V. cholerae and P. aeruginosa in both nutrient rich and physiological conditions. We were also able to confirm that inhibition of this enzyme, in both growth conditions, resulted in decreased biofilm production, subsequently eliminating one of the main mechanisms for antibiotic resistance of these bacteria.
M.S. in Biology, May 2017
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ROLES OF RESPIRATORY CHAIN ENZYMES IN BIOFILM FORMATION OF PSEUDOMONAS AERUGINOSA
Title
ROLES OF RESPIRATORY CHAIN ENZYMES IN BIOFILM FORMATION OF PSEUDOMONAS AERUGINOSA
Creator
DING, JIE
Date
2019
Description
Pseudomonas aeruginosa is a Gram-negative, rod-shaped bacterium, resistant to many antibiotics. It can cause several chronic infections such...
Show morePseudomonas aeruginosa is a Gram-negative, rod-shaped bacterium, resistant to many antibiotics. It can cause several chronic infections such as lung, bloodstream, urinary tract, and surgical wound infections. This bacterium produces biofilms which confer resistance to hazardous environments. P. aeruginosa contains five stages of colony development, which are planktonic attachment, cell to cell adhesion, proliferation, maturation, and dispersion. After five stages, biofilms of P. aeruginosa are matured. The biofilm structure produced by P. aeruginosa is important for cell survival, providing protection and resistance to harsh environment and antibiotics. In this research, the biofilms formed by wildtype strain PA01 and mutated strains of PA14, including NDH-2, NQR F, and NUO I, were developed in LB medium and Artificial Urine Medium separately for 96 hours. After washing, collecting, and staining the biofilms, the analyses of measurement of OD562 showed that in LB medium, PA01 formed more biofilms than mutants while NUO I and NDH2 had less biofilms, although not significantly. In AUM the situation was different. PA01 formed least biofilms while NQR F formed largest biofilms than any other strains. Also, the NDH-2 formed more biofilms than NUO I in AUM. The deficiencies of enzymes loss in those strains result in growing biofilm concentrations. Because the difference was not significant, we can only say that the NQR and NADH dehydrogenases have important roles in biofilm formation.
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Role of Respiratory Enzymes on Growth of Pseudomonas aeruginosa in Luria-Bertani and Artificial Urine Media
Title
Role of Respiratory Enzymes on Growth of Pseudomonas aeruginosa in Luria-Bertani and Artificial Urine Media
Creator
Hu, Yuyao
Date
2018
Description
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes many hospital-acquired infections. The treatment of P. aeruginosa...
Show morePseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes many hospital-acquired infections. The treatment of P. aeruginosa infections is difficult due its multiple defense and adaptive mechanisms. One of these mechanisms is the flexibility of its respiratory chain. The human cell respiratory chain is composed of four respiratory enzymes with low mechanistic flexibility. On the other hand, the respiratory chain of P. aeruginosa contains 23 respiratory enzymes that ensure survival under harsh conditions. To elucidate the physiologic role of these respiratory enzymes, our research compared the growth parameters of wild type P. aeruginosa and nine separate respiratory enzyme mutants, in both LB and artificial urine media (AUM). The deletion mutants include the sodium-translocating NADH: quinone oxidoreductase, complex I, succinate dehydrogenase, cytochrome bc1 complex, cytochrome c oxidase and cyanide insensitive terminal oxidase. Our data indicate that the growth curve of the cytochrome bc1 complex knockout mutant showed a significantly lower yield and lower growth rate compared with the wild type in both LB and AUM media. Additionally, the cyanide insensitive terminal oxidase mutant showed a significant lower yield compared with the wild type in LB media growth. These results indicate the important roles of these enzymes in the cell biology of P. aeruginosa.
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