Molecular Biology Commons^™

Understanding The Molecular Mechanisms Of Photoferrotrophy And Phototrophic Extracellular Electron Uptake, Dinesh Gupta

Arts & Sciences Electronic Theses and Dissertations

Several anoxygenic phototrophs grow by utilizing soluble iron or insoluble mixed-valence iron minerals (such as rust) as electron donors to fix carbon dioxide using light energy, a process called photoferrotrophy. Photoferrotrophs can also use electron donors such as poised electrodes that serve as proxies for rust via phototrophic extracellular electron uptake (EEU). Despite the recognition that these two related microbial processes contribute to various biogeochemical cycles such as iron and carbon, the electron uptake mechanisms underlying photoferrotrophy and phototrophic EEU are poorly understood. To address the key knowledge gaps in our understanding of these microbial metabolisms, here we characterized Rhodopseudomonas …

Engineering Natural Competence Into The Fast-Growing Cyanobacterium Synechococcus Elongatus Utex 2973, Kristen Elizabeth Wendt

Arts & Sciences Electronic Theses and Dissertations

Synechococcus elongatus UTEX 2973 is the fastest growing cyanobacterium discovered to date. Using water, carbon dioxide, and light alone, this organism can double in 1.5 hours under optimal conditions. The accelerated doubling exhibited by Synechococcus 2973 makes it a prime candidate to serve as a model photoautotrophic system. However, Synechococcus 2973 lacks one highly desirable feature: it cannot undergo natural transformation. This thesis seeks to engineer this capacity into this fast-growing system in order to create an organism that is both fast growing and naturally competent. Synechococcus 2973 is a unique platform because it is >99% genetically identical to another …

Mitochondrial Morphology, Oxidative Stress Resistance, And Pathogenesis In Cryptococcus Neoformans, Andrew Lee Chang

Arts & Sciences Electronic Theses and Dissertations

Cryptococcus neoformans is an important pathogen that annually kills 200,000 people worldwide. It survives in the environment as a yeast or spore and can also proliferate within host macrophages after being inhaled into the lungs. In conditions of immunocompromise, cryptococcal cells can escape from the lungs to the brain, where they cause a deadly meningoencephalitis that is both difficult and expensive to treat. Cryptococcal adaptation to the harsh lung environment is a critical first step in its pathogenesis, and consequently a compelling topic of study. This adaptation is mediated by a complex transcriptional program that integrates cellular responses to environmental …

Development Of An In Vitro Culture System For Cryptosporidium Parvum, Georgia Wilke

Arts & Sciences Electronic Theses and Dissertations

Cryptosporidium is a genus of protozoan parasites that causes diarrheal disease in humans and other animals. There are two major species that cause disease in humans: C. parvum, which infects both humans and animals, and C. hominis, which primarily infects humans. A recent study investigating the etiologies of pediatric diarrheal illness in Africa and South Asia found that Cryptosporidium is the 2nd most prevalent cause of diarrhea in infants and may be a contributing factor to chronic malnutrition. This discovery has led to renewed interest in studying this parasite and a reexamination of the barriers to studying Cryptosporidium. The main …

Exploring Host-Virus Interactions In Caenorhabditis Nematodes, Kevin Chen

Arts & Sciences Electronic Theses and Dissertations

Caenorhabditis elegans is a powerful model organism that has elucidated many biological questions in the fields of genetics, development, and neurobiology. In addition, C. elegans has been used in the past decade to investigate host-pathogen interactions with bacteria and fungi. The recent identification of nematode viruses that naturally infect C. elegans and Caenorhabditis briggsae provides a unique opportunity to define host-virus interactions in these model hosts.

This dissertation first explored the transcriptional response of C. elegans and C. briggsae to virus infection by RNA-seq. I identified a total of 320 differentially expressed genes (DEGs) in C. elegans following Orsay virus …

The Role Of Rna Interference In The Control Of Leishmania Rna Virus 1 Infection, Erin Acino Brettmann

Arts & Sciences Electronic Theses and Dissertations

The presence of Leishmania RNA virus 1 (LRV1) in parasites of the Leishmania (Viannia) subgenus increases the virulence of the parasite in mouse models of leishmaniasis and is correlated with treatment failure, relapse, and the development of mucocutaneous disease in humans. LRV1 is not shed or infectious; rather, the infection is persistent, and as yet it is unknown how the parasite controls virus levels. Many eukaryotic organisms use RNA interference (RNAi) to limit virus replication, and Leishmania (Viannia) parasites have an active RNAi pathway. To determine whether Leishmania are capable of using RNAi to control LRV1, we sequenced sRNAs from …