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Pseudomonas Aeruginosa-Candida Albicans Interactions: Localization And Fungal Toxicity Of A Phenazine Derivative, Jane Gibson, Arpanah Sood, Deborah A. Hogan Nov 2008

Pseudomonas Aeruginosa-Candida Albicans Interactions: Localization And Fungal Toxicity Of A Phenazine Derivative, Jane Gibson, Arpanah Sood, Deborah A. Hogan

Dartmouth Scholarship

Phenazines are redox-active small molecules that play significant roles in the interactions between pseudomonads and diverse eukaryotes, including fungi. When Pseudomonas aeruginosa and Candida albicans were cocultured on solid medium, a red pigmentation developed that was dependent on P. aeruginosa phenazine biosynthetic genes. Through a genetic screen in combination with biochemical experiments, it was found that a P. aeruginosa-produced precursor to pyocyanin, proposed to be 5-methyl-phenazinium-1-carboxylate (5MPCA), was necessary for the formation of the red pigmentation. The 5MPCA-derived pigment was found to accumulate exclusively within fungal cells, where it retained the ability to be reversibly oxidized and reduced, and its …


Spatial And Temporal Patterns In The Microbial Diversity Of A Meromictic Soda Lake In Washington State, Pedro A. Dimitriu, Holly C. Pinkart, Brent M. Peyton, Melanie R. Mormile Jul 2008

Spatial And Temporal Patterns In The Microbial Diversity Of A Meromictic Soda Lake In Washington State, Pedro A. Dimitriu, Holly C. Pinkart, Brent M. Peyton, Melanie R. Mormile

All Faculty Scholarship for the College of the Sciences

The microbial community diversity and composition of meromictic Soap Lake were studied using culture-dependent and culture-independent approaches. The water column and sediments were sampled monthly for a year. Denaturing gradient gel electrophoresis of bacterial and archaeal 16S rRNA genes showed an increase in diversity with depth for both groups. Late-summer samples harbored the highest prokaryotic diversity, and the bacteria exhibited less seasonal variability than the archaea. Most-probable-number assays targeting anaerobic microbial guilds were performed to compare summer and fall samples. In both seasons, the anoxic samples appeared to be dominated by lactate-oxidizing sulfate-reducing prokaryotes. High numbers of lactate- and acetate-oxidizing …


Candida Albicans Tup1 Is Involved In Farnesol-Mediated Inhibition Of Filamentous-Growth Induction, Bessie W. Kebaara, Melanie L. Langford, Dhammika H. M. L. P. Navarathna, Raluca Dumitru, Kenneth W. Nickerson, Audrey L. Atkin Jun 2008

Candida Albicans Tup1 Is Involved In Farnesol-Mediated Inhibition Of Filamentous-Growth Induction, Bessie W. Kebaara, Melanie L. Langford, Dhammika H. M. L. P. Navarathna, Raluca Dumitru, Kenneth W. Nickerson, Audrey L. Atkin

Kenneth Nickerson Papers

Candida albicans is a dimorphic fungus that can interconvert between yeast and filamentous forms. Its ability to regulate morphogenesis is strongly correlated with virulence. Tup1, a transcriptional repressor, and the signaling molecule farnesol are both capable of negatively regulating the yeast to filamentous conversion. Based on this overlap in function, we tested the hypothesis that the cellular response to farnesol involves, in part, the activation of Tup1. Tup1 functions with the DNA binding proteins Nrg1 and Rfg1 as a transcription regulator to repress the expression of hypha-specific genes. The tup1/tup1 and nrg1/nrg1 mutants, but not the rfg1/rfg1 mutant, failed to …


Old Acetogens, New Light, Steven L. Daniel, Harold L. Drake, Anita S. Gößner Jan 2008

Old Acetogens, New Light, Steven L. Daniel, Harold L. Drake, Anita S. Gößner

Faculty Research & Creative Activity

Acetogens utilize the acetyl-CoA Wood-Ljungdahl pathway as a terminal electron-accepting, energy-conserving, CO2-fixing process. The decades of research to resolve the enzymology of this pathway (1) preceded studies demonstrating that acetogens not only harbor a novel CO2-fixing pathway, but are also ecologically important, and (2) overshadowed the novel microbiological discoveries of acetogens and acetogenesis. The first acetogen to be isolated, Clostridium aceticum, was reported by Klaas Tammo Wieringa in 1936, but was subsequently lost. The second acetogen to be isolated, Clostridium thermoaceticum, was isolated by Francis Ephraim Fontaine and co-workers in 1942. C. thermoaceticum became the most extensively studied acetogen and …


Old Acetogens, New Light, Steven Daniel, Harold Drake, Anita Gößner Jan 2008

Old Acetogens, New Light, Steven Daniel, Harold Drake, Anita Gößner

Faculty Research & Creative Activity

Acetogens utilize the acetyl-CoA Wood-Ljungdahl pathway as a terminal electron-accepting, energy-conserving, CO2-fixing process. The decades of research to resolve the enzymology of this pathway (1) preceded studies demonstrating that acetogens not only harbor a novel CO2-fixing pathway, but are also ecologically important, and (2) overshadowed the novel microbiological discoveries of acetogens and acetogenesis. The first acetogen to be isolated, Clostridium aceticum, was reported by Klaas Tammo Wieringa in 1936, but was subsequently lost. The second acetogen to be isolated, Clostridium thermoaceticum, was isolated by Francis Ephraim Fontaine and co-workers in 1942. C. thermoaceticum became the most extensively studied acetogen and …


Ship Ballast Tanks: How Microbes Travel The World, Fred C. Dobbs Jan 2008

Ship Ballast Tanks: How Microbes Travel The World, Fred C. Dobbs

OES Faculty Publications

As the international shipping fleet travels the oceans, it carries with it hidden cargoes of microbes. Fred C. Dobbs explores the hazards posed and what can be done to counteract them.