Organismal Biological Physiology Commons^™

Steroid Receptor Isoform Expression In Drosophila Nociceptor Neurons Is Required For Normal Dendritic Arbor And Sensitivity, Aidan L. Mcparland, Taylor L. Follansbee, Gwendolyn D. Vesenka, Alexandra E. Panaitiu, Geoffrey K. Ganter

Biology Student Publications

Steroid hormones organize many aspects of development, including that of the nervous system. Steroids also play neuromodulatory and other activational roles, including regulation of sensitivity to painful stimuli in mammals. In Drosophila, ecdysteroids are the only steroid hormones, and therefore the fly represents a simplified model system in which to explore mechanisms of steroid neuromodulation of nociception. In this report, we present evidence that ecdysteroids, acting through two isoforms of their nuclear ecdysone receptor (EcR), modulate sensitivity to noxious thermal and mechanical stimuli in the fly larva. We show that EcRA and EcRB1 are expressed by third instar larvae in …

A Tail Of Two Phages: Genomic And Functional Analysis Of Listeria Monocytogenes Phages Vb_Lmos_188 And Vb_Lmos_293 Reveal The Receptor-Binding Proteins Involved In Host Specificity, Aidan Casey, Kieran Jordan, Horst Neve, Aidan Coffey, Olivia Mcauliffe

Department of Biological Sciences Publications

The physical characteristics of bacteriophages establish them as viable candidates for downstream development of pathogen detection assays and biocontrol measures. To utilize phages for such purposes, a detailed knowledge of their host interaction mechanisms is a prerequisite. There is currently a wealth of knowledge available concerning Gram-negative phage-host interaction, but little by comparison for Gram-positive phages and Listeria phages in particular. In this research, the lytic spectrum of two recently isolated Listeria monocytogenes phages (vB_LmoS_188 and vB_LmoS_293) was determined, and the genomic basis for their observed serotype 4b/4e host-specificity was investigated using comparative genomics. The late tail genes of these …

Generation And Assessment Of Muscular Mutations In Caenorhabditis Elegans, Katie N. Reget

DePaul Discoveries

A study of egg laying muscular mutations in C. elegans was conducted over a span of ten weeks. Parent (EGL-19) and wild type (N2) were exposed to mutagenesis and integration mutation techniques to generate genetic and physical different mutants. Overall, four genetic, physical and phenotypically unique worms were generated for the process of mutagenesis. The worms used in the process of integration were found to have shortened life spans, reduced size and decrease numbers of progeny.

Evolution Of Sperm Activation In Nematodes, Qing Wei

Graduate School of Biomedical Sciences Theses and Dissertations

Three hermaphroditic species in the nematode genus Caenorhabditis - C. elegans, C. briggsae and C. tropicalis evolved independently from a male/female ancestor. Thus, the hermaphroditic reproductive system provides an ideal subject for studying the origin of new complex traits. Previous studies implied that this transition required two steps: a mutation that caused XY animals to make sperm, and a mutation that allowed XX spermatids to activate and fertilize oocytes. In this dissertation, I show how sperm activation is regulated in different hermaphroditic species.

First, I used TALENs to create genetic tools for C. briggsae and C. tropicalis. These tools were …

Characterization And Investigation Of Fungi Inhabiting The Gastrointestinal Tract Of Healthy And Diseased Humans, Mallory J. Suhr

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Gastrointestinal microbiome studies have failed to include fungi in total community analyses. As a result, their diversity and function in the gut is poorly understood. Recent work has begun to uncover the role intestinal fungi play in diet, immune system development, interactions with other microorganisms in the gut, and pathogenesis of diseases. Advances in sequencing technologies allow for the ability to profile the fungal gut microbiome (“mycobiome”) in healthy and diseased states. This thesis explores the mycobiome in 1) healthy humans with a vegetarian diet and 2) pediatric small bowel transplant recipients that develop fungal bloodstream infections.

The gut mycobiome …

A Phylogenetic Analysis Of Dictyostelium Purpureum Based On Nuclear Rdna Sequences, Mahmoud Suliman

Graduate Theses and Dissertations

Dictyostelids (cellular slime molds) are eukaryotic microorganisms that have both unicellular and multicellular stages during their life cycle. In this study, a molecular phylogenetic analysis was conducted for isolates of one species (Dictyostelium purpureum) based DNA sequences of the ITS, 5.8S and SSU regions of nuclear rDNA. Moreover, a detailed morphological study was carried out using images obtained with both dissecting and compound microscopes. Mating experiments were carried out to assess macrocysts formation between each pair of isolates. The constructed molecular phylogenetic trees indicate that (1) D. purpureum isolates are more closely related to each other than to other species …

Functional Screening Of The Cronobacter Sakazakii Baa-894 Genome Reveals A Role For Prop (Esa_02131) In Carnitine Uptake, Audrey Feeney, Roy D. Sleator

Department of Biological Sciences Publications

Cronobacter sakazakii is a neonatal pathogen responsible for up to 80% of fatalities in infected infants. Low birth weight infants and neonates infected with C. sakazakii suffer necrotizing enterocolitis, bacteraemia and meningitis. The mode of transmission most often associated with infection is powdered infant formula (PIF) which, with an aw of ∼0.2, is too low to allow most microorganisms to persist. Survival of C. sakazakii in environments subject to extreme hyperosmotic stress has previously been attributed to the uptake of compatible solutes including proline and betaine. Herein, we report the construction and screening of a C. sakazakii genome bank and …

Exploring The Physiological Role Of Vibrio Fischeri Pepn, Sally L. Cello

Master's Theses

The primary contributor to Vibrio fischeri aminopeptidase activity is aminopeptidase N, PepN. Colonization assays revealed the pepN mutant strain to be deficient at forming dense aggregates and populating the host’s light organ compared to wildtype within the first 12 hours of colonization; however the mutant competed normally at 24 hours. To address the role of PepN in colonization initiation and establish additional phenotypes for the pepN mutant strain, stress response and other physiological assays were employed. Marked differences were found between pepN mutant and wildtype strain in response to salinity, acidity, and antibiotic tolerance. This study has provided a foundation …

Promises And Prospects Of Microbiome Studies, Maria C. Rivera, Jacques Izard

Department of Food Science and Technology: Faculty Publications

Since Anthony van Leeuwenhoek, first microscopic observations of the unseen microbiota and the more recent realization that little of the microbes in the biosphere are known, humans have developed a deep curiosity to fully understand the inner workings of the microbial realm. Our ability to characterize the complexity of microbial communities in their natural habitats has dramatically improved over the past decade thanks to advances in high-throughput methodologies. By eliminating the need to isolate and culture individual species, metagenomics approaches have removed many of the obstacles that hindered research in the ecology of mixed microbial consortia, providing valuable information about …

Characterization Of The Ecological Role Of Genes Mediating Acid Resistance In Lactobacillus Reuteri During Colonization Of The Gastrointestinal Tract, Janina A. Krumbeck, Nathan L Marsteller, Steven Frese, Daniel A. Peterson, Amanda Ramer-Tait, Robert W. Hutkins, Jens Walter

Department of Food Science and Technology: Faculty Publications

Rodent-derived strains of Lactobacillus reuteri densely colonize the forestomach of mice and possess several genes whose predicted functions constitute adaptations towards an acidic environment. The objective of this study was to systematically determine which genes of L. reuteri 100-23 contribute to tolerance towards host gastric acid secretion. Genes predicted to be involved in acid resistance were inactivated, and their contribution to survival under acidic conditions was confirmed in model gastric juice. Fitness of five mutants that showed impaired in vitro acid resistance were then compared through competition experiments in ex-germ-free mice that were either treated with omeprazole, a proton-pump inhibitor …