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Full-Text Articles in Microbiology

Fluid Dynamic Factors As A Cause And Effect Of Biofilm Formation Of Staphylococcus Aureus Biofilms, Erica Sherman Oct 2016

Fluid Dynamic Factors As A Cause And Effect Of Biofilm Formation Of Staphylococcus Aureus Biofilms, Erica Sherman

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Staphylococcus aureus bacteria are able to form biofilms and distinctive tower structures that facilitate their ability to tolerate treatment and to spread within the human body. The formation of towers, which break off, get carried downstream and serve to initiate biofilms in other parts of the body are of particular interest here. It is known that flow conditions play a role in the development, dispersion and propagation of biofilms. The influence of flow on tower formation and what factors lead to tower formation is not at all understood The hypothesis being examined is that tower structures form within a specific …


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 Jun 2016

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 …


Biosynthesis And Roles Of Virulence Conferring Cell Wall Associated Dimycocerosate Esters In Mycobacterium Marinum, Poornima Mohandas Jun 2016

Biosynthesis And Roles Of Virulence Conferring Cell Wall Associated Dimycocerosate Esters In Mycobacterium Marinum, Poornima Mohandas

Dissertations, Theses, and Capstone Projects

Mycobacterial species include a variety of obligate and opportunistic pathogens that cause several important diseases affecting mankind such as tuberculosis and leprosy. The most unique feature of these bacteria is their intricate cell wall that poses a permeability barrier to antibiotics and contributes to their pathogenicity and persistence within the host. The cell wall hosts several complex lipids such as dimycocerosate esters (DIMs), which are found in many clinically relevant pathogenic species of mycobacteria. DIMs have been implicated in the virulence of mycobacteria and play a major role in helping the bacteria evade host immune responses. It is therefore crucial …


Flood Events Can Reduce Key Fatty Acid Content Of Early-Stage Benthic Algal Assemblages In An Urban Stream, Sarah Whorley, John Wehr Jun 2016

Flood Events Can Reduce Key Fatty Acid Content Of Early-Stage Benthic Algal Assemblages In An Urban Stream, Sarah Whorley, John Wehr

Articles & Book Chapters

Effects of urbanization on stream chemistry and biota have been widely examined. However, few studies quantify the effect of urban stream characteristics on the biochemical properties of basal food resources, such as benthic algae, which can affect aquatic consumers and food webs. A common feature of urban streams is the high frequency of short floods, which may disrupt aquatic communities and their biotic controls. These disturbances can create algal assemblages low in biomass and which remain in early successional stages. This study examined the effects of frequent flood events and macroinvertebrate grazing on biomass, elemental stoichiometry, and essential fatty acid …


Controlling Microbial Safety Challenges Of Meat Using High Voltage Atmospheric Cold Plasma, Lu Han, Dana Ziuzina, Caitlin Marie Heslin, Daniela Boehm, Apurva Patange, David Millan-Sango, Vasilis Valdramidis, Patrick Cullen, Paula Bourke Jan 2016

Controlling Microbial Safety Challenges Of Meat Using High Voltage Atmospheric Cold Plasma, Lu Han, Dana Ziuzina, Caitlin Marie Heslin, Daniela Boehm, Apurva Patange, David Millan-Sango, Vasilis Valdramidis, Patrick Cullen, Paula Bourke

Articles

Atmospheric cold plasma (ACP) is a non-thermal technology, effective against a wide range of pathogenic microorganisms. Inactivation efficacy results from plasma generated reactive species. These may interact with any organic components in a test matrix including the target microorganism, thus food components may exert a protective effect against the antimicrobial mode of action. The effect of an in-package high voltage ACP process applied in conjunction with common meat processing MAP gas compositions as well as bacteria type and meat model media composition have been investigated to determine the applicability of this technology for decontamination of safety challenges associated with meat …