Life Sciences Commons^™

The Pseudomonas Aeruginosa Efflux Pump Mexghi-Opmd Transports A Natural Phenazine That Controls Gene Expression And Biofilm Development, Hassan Sakhtah, Leslie Koyama, Yihan Zhang, Diana K. Morales, Blanche Fields, Alexa Price-Whelan, Deborah Hogan

Dartmouth Scholarship

Redox-cycling compounds, including endogenously produced phenazine antibiotics, induce expression of the efflux pump MexGHI-OpmD in the opportunistic pathogen Pseudomonas aeruginosa Previous studies of P. aeruginosa virulence, physiology, and biofilm development have focused on the blue phenazine pyocyanin and the yellow phenazine-1-carboxylic acid (PCA). In P. aeruginosa phenazine biosynthesis, conversion of PCA to pyocyanin is presumed to proceed through the intermediate 5-methylphenazine-1-carboxylate (5-Me-PCA), a reactive compound that has eluded detection in most laboratory samples. Here, we apply electrochemical methods to directly detect 5-Me-PCA and find that it is transported by MexGHI-OpmD in P. aeruginosa strain PA14 planktonic and biofilm cells. We …

Spatiotemporal Control Of Staphylococcus Aureus Biofilm Development, Derek E. Moormeier

Theses & Dissertations

Chronic biofilm-related infections caused by the human pathogen Staphylococcus aureus often lead to significant increases in morbidity and mortality in both hospital- and community-associated settings. Typically, S. aureus biofilm development occurs in three stages: 1) attachment, 2) tower maturation, and 3) dispersal. Here, utilizing BioFlux1000 time-lapse microscopy we have expanded upon these fundamental stages of biofilm development and also unveiled and characterized two additional stages (multiplication and exodus).

The attachment and multiplication stages were shown to be protease sensitive but independent of most cell surface-associated proteins. Following multiplication, an exodus of the biofilm population that followed the transition of the …

Identification Of Novel Cyclic Lipopeptides From A Positional Scanning Combinatorial Library With Enhanced Antibacterial And Antibiofilm Activities, Nina Bionda, Renee M. Fleeman, César De La Fuente-Núñez, Maria C. Rodriguez, Fany Reffuveille, Lindsey N. Shaw, Irena Pastar, Stephen C Davis, Robert E W Hancock, Predrag Cudic

Molecular Biosciences Faculty Publications

Treating bacterial infections can be difficult due to innate or acquired resistance mechanisms, and the formation of biofilms. Cyclic lipopeptides derived from fusaricidin/LI-F natural products represent particularly attractive candidates for the development of new antibacterial and antibiofilm agents, with the potential to meet the challenge of bacterial resistance to antibiotics. A positional-scanning combinatorial approach was used to identify the amino acid residues responsible for driving antibacterial activity, and increase the potency of these cyclic lipopeptides. Screening against the antibiotic resistant ESKAPE pathogens revealed the importance of hydrophobic as well as positively charged amino acid residues for activity of this class …

Investigating The Regulatory Mechanisms By Which Arabinose And Sypa Control Biofilm Formation In Vibrio Fischeri, Sheila Paris

Master's Theses

Biofilms are surface-associated microbial communities surrounded by an extracellular matrix. Through biofilm formation, many pathogens and symbionts are able to colonize, survive, and persist in their host. A model system used to study biofilm formation is the symbiotic bacterium Vibrio fischeri, which colonizes its host, the squid Euprymna scolopes. Complex signaling between the squid and the bacteria is essential for the proper regulation of biofilm formation as well as for persistent colonization.

The signal(s) that promote host-relevant biofilm formation are as-yet unknown, but recently it was discovered that the sugar, L-arabinose, serves as a unique signal to promote biofilm formation …