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Flynn, J. M.

Publications and source records attributed to Flynn, J. M..

20 records · Page 2Linked to original sources

Resource-Driven Encounters and the Induction of Disease Among Consumers

Submitted Manuscript 2016. Territorial animals share a variety of common resources, which can be a major driver of conspecific encounter rates. We examine how changes in resource availability influence the rate of encounters among individuals in a consumer population by implementing a spatially explicit model for resource visitation behavior by consumers. Using data from 2009 and 2010 in Etosha National Park, we verify our model's prediction that there is a saturation effect in the expected number of jackals that visit a given carcass site as carcasses become abundant. However, this does not directly imply that the overall resource-driven encounter rate among jackals decreases. This is because the increase in available carcasses is accompanied by an increase in the number of jackals that detect and potentially visit carcasses. Using simulations and mathematical analysis of our consumer-resource interaction model, we characterize key features of the relationship between resource-driven encounter rate and model parameters. These results are used to investigate a standing hypothesis that the outbreak of a fatal disease among zebras can potentially lead to an outbreak of an entirely different disease in the jackal population, a process we refer to as indirect induction of disease.

ecology↗

Genome-wide survey of Pseudomonas aeruginosa PA14 reveals a role for the glyoxylate pathway and extracellular proteases in the limited utilization of mucin

Chronic airway infections by the opportunistic pathogen Pseudomonas aeruginosa are major cause of mortality in cystic fibrosis (CF) patients. While this bacterium has been extensively studied for its virulence mechanisms, biofilm growth and immune evasion within the CF airways, comparatively little is known about the nutrient sources that sustain its growth in vivo. Respiratory mucins represent a potentially abundant bioavailable nutrient source, though we have recently shown that canonical pathogens inefficiently use these host glycoproteins as a growth substrate. Yet, given that P. aeruginosa, particularly in its biofilm mode of growth is thought to grow slowly in vivo, the inefficient use of mucin glycoproteins may have relevance to its persistence within the CF airways. To this end, here we use whole genome fitness analysis combining transposon mutagenesis with high throughput sequencing (TnSeq) to identify genetic determinants required for P. aeruginosa growth using intact purified mucins as a sole carbon source. Our analysis reveals a biphasic growth phenotype, during which the glyoxylate pathway and amino acid biosynthetic machinery are required for mucin utilization. Secondary analyses confirmed the simultaneous liberation and consumption of acetate during mucin degradation and revealed a central role for the extracellular proteases LasB and AprA. Together, these studies identified the P. aeruginosa genes required for mucin-based nutrient acquisition and reveal a host-pathogen dynamic that may contribute to its persistence within the CF airways.

microbiology↗