The Carbon Monoxide Releasing Molecule CORM-2 Attenuates Pseudomonas aeruginosa Biofilm Formation

Chronic infections resulting from biofilm formation are difficult to eradicate with current antimicrobial agents and consequently new therapies are needed. This work demonstrates that the carbon monoxide-releasing molecule CORM-2, previously shown to kill planktonic bacteria, also attenuates surface-associated growth of the Gram-negative pathogen Pseudomonas aeruginosa by both preventing biofilm maturation and killing bacteria within the established biofilm. CORM-2 treatment has an additive effect when combined with tobramycin, a drug commonly used to treat P. aeruginosa lung infections. CORM-2 inhibited biofilm formation and planktonic growth of the majority of clinical P. aeruginosa isolates tested, for both mucoid and non-mucoid strains. While CORM-2 treatment increased the production of reactive oxygen species by P. aeruginosa biofilms, this increase did not correlate with bacterial death. These data demonstrate that CO-RMs possess potential novel therapeutic properties against a subset of P. aeruginosa biofilm related infections

Candida albicans Ethanol Stimulates Pseudomonas aeruginosa WspR-Controlled Biofilm Formation as Part of a Cyclic Relationship Involving Phenazines

In chronic infections, pathogens are often in the presence of other microbial species. For example, Pseudomonas aeruginosa is a common and detrimental lung pathogen in individuals with cystic fibrosis (CF) and co-infections with Candida albicans are common. Here, we show that P. aeruginosa biofilm formation and phenazine production were strongly influenced by ethanol produced by the fungus C. albicans. Ethanol stimulated phenotypes that are indicative of increased levels of cyclic- di-GMP (c-di-GMP), and levels of c-di-GMP were 2-fold higher in the presence of ethanol. Through a genetic screen, we found that the diguanylate cyclase WspR was required for ethanol stimulation of c-di-GMP. Multiple lines of evidence indicate that ethanol stimulates WspR signaling through its cognate sensor WspA, and promotes WspR-dependent activation of Pel exopolysaccharide production, which contributes to biofilm maturation. We also found that ethanol stimulation of WspR promoted P. aeruginosa colonization of CF airway epithelial cells. P. aeruginosa production of phenazines occurs both in the CF lung and in culture, and phenazines enhance ethanol production by C. albicans. Using a C.albicans adh1/adh1 mutant with decreased ethanol production, we found that fungal ethanol strongly altered the spectrum of P. aeruginosa phenazines in favor of those that are most effective against fungi. Thus, a feedback cycle comprised of ethanol and phenazines drives this polymicrobial interaction, and these relationships may provide insight into why co-infection with both P. aeruginosa and C. albicans has been associated with worse outcomes in cystic fibrosis

Nε−Lysine Acetylation of a Bacterial Transcription Factor Inhibits Its DNA-Binding Activity

Evidence suggesting that eukaryotes and archaea use reversible Nε-lysine (Nε-Lys) acetylation to modulate gene expression has been reported, but evidence for bacterial use of Nε-Lys acetylation for this purpose is lacking. Here, we report data in support of the notion that bacteria can control gene expression by modulating the acetylation state of transcription factors (TFs). We screened the E. coli proteome for substrates of the bacterial Gcn5-like protein acetyltransferase (Pat). Pat acetylated four TFs, including the RcsB global regulatory protein, which controls cell division, and capsule and flagellum biosynthesis in many bacteria. Pat acetylated residue Lys180 of RcsB, and the NAD+-dependent Sir2 (sirtuin)-like protein deacetylase (CobB) deacetylated acetylated RcsB (RcsBAc), demonstrating that Nε-Lys acetylation of RcsB is reversible. Analysis of RcsBAc and variant RcsB proteins carrying substitutions at Lys180 provided biochemical and physiological evidence implicating Lys180 as a critical residue for RcsB DNA-binding activity. These findings further the likelihood that reversible Nε-Lys acetylation of transcription factors is a mode of regulation of gene expression used by all cells

Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications

This work was supported by a restricted research grant of Bayer AG

Yosemite Valley : a Cultural, Historical, and Botanical Experience

Color poster with text, images, and photographs.During the fall of 2013 a group of University of Wisconsin--Eau Claire students and professors conducted research in Yosemite National Park. The purpose of the study was to understand the cultural history of the park in order to understand the significance of our scientific findings and to provide an overall backdrop for the trip.University of Wisconsin--Eau Claire Office of Research and Sponsored Programs

Becoming Locals : Place-Making and the Hmong in Eau Claire, Wisconsin

Color poster with text, maps, and photographs.Since they first began arriving in the United States in the late 1970s, Hmong refugees have established numerous communities across Wisconsin and Minnesota. Though immigration from Southeast Asia continues, the Hmong community is well-established as first- and second-generation Hmong-Americans participate in community and local place-making. This study examines the incorporation of immigrants into the non-immigrant host community in Eau Claire County.University of Wisconsin--Eau Claire Office of Research and Sponsored Program

<i>Candida albicans</i> Ethanol Stimulates <i>Pseudomonas aeruginosa</i> WspR-Controlled Biofilm Formation as Part of a Cyclic Relationship Involving Phenazines

<div><p>In chronic infections, pathogens are often in the presence of other microbial species. For example, <i>Pseudomonas aeruginosa</i> is a common and detrimental lung pathogen in individuals with cystic fibrosis (CF) and co-infections with <i>Candida albicans</i> are common. Here, we show that <i>P. aeruginosa</i> biofilm formation and phenazine production were strongly influenced by ethanol produced by the fungus <i>C. albicans</i>. Ethanol stimulated phenotypes that are indicative of increased levels of cyclic-di-GMP (c-di-GMP), and levels of c-di-GMP were 2-fold higher in the presence of ethanol. Through a genetic screen, we found that the diguanylate cyclase WspR was required for ethanol stimulation of c-di-GMP. Multiple lines of evidence indicate that ethanol stimulates WspR signaling through its cognate sensor WspA, and promotes WspR-dependent activation of Pel exopolysaccharide production, which contributes to biofilm maturation. We also found that ethanol stimulation of WspR promoted <i>P. aeruginosa</i> colonization of CF airway epithelial cells. <i>P. aeruginosa</i> production of phenazines occurs both in the CF lung and in culture, and phenazines enhance ethanol production by <i>C. albicans</i>. Using a <i>C. albicans adh1</i>/<i>adh1</i> mutant with decreased ethanol production, we found that fungal ethanol strongly altered the spectrum of <i>P. aeruginosa</i> phenazines in favor of those that are most effective against fungi. Thus, a feedback cycle comprised of ethanol and phenazines drives this polymicrobial interaction, and these relationships may provide insight into why co-infection with both <i>P. aeruginosa</i> and <i>C. albicans</i> has been associated with worse outcomes in cystic fibrosis.</p></div