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Full-Text Articles in Biology

Canonical Notch Signaling Positively Regulates Mir-155 Transcription In A Nfκb-Dependent Manner, Joe Torres Jul 2018

Canonical Notch Signaling Positively Regulates Mir-155 Transcription In A Nfκb-Dependent Manner, Joe Torres

Doctoral Dissertations

MicroRNA-155 (miR-155) is an important pro-inflammatory molecule that controls immune responses in both physiological and pathological settings. Although miR-155 is well studied, little is known about its transcriptional regulation in T cells. We sought to further understand the mechanisms by which miR-155 transcription is induced following T cell activation. We found that miR-155 transcription is dependent on the activity of the Notch and NFkB signaling pathways. It was determined that the canonical Notch signaling pathway was involved in this regulation and that it was dependent upon the activation of NFkB. Additional work confirmed that both NFkB and Notch1 directly bind …


Effects Of Floral Phytochemicals On Growth And Evolution Of A Parasite Of Bumble Bees, Evan Palmer-Young Mar 2018

Effects Of Floral Phytochemicals On Growth And Evolution Of A Parasite Of Bumble Bees, Evan Palmer-Young

Doctoral Dissertations

Background: Nectar and pollen are rich in phytochemicals, some of which can reduce disease in pollinators, including agriculturally important honey and bumble bees. Floral phytochemicals could influence the ecological and evolutionary relationships between plants, their pollinators, and parasites that cause pollinator disease. Antiparasitic effects of phytochemicals could be exploited to ameliorate pollinator disease and decline, and thereby sustain pollinator-dependent agricultural production. However, prior studies showed variable effects of phytochemicals on infection in live bees, where differences in bee genotype, abiotic conditions, and parasite strain could influence results. Approach: I used cell cultures of the intestinal trypanosome parasite of bumble bees, …


A Novel Population Of Natural Killer Cells Plays A Critical Role In The Depletion Of Splenic B2 B Cells During Experimental African Trypanosomiasis, Deborah Frenkel Mar 2015

A Novel Population Of Natural Killer Cells Plays A Critical Role In The Depletion Of Splenic B2 B Cells During Experimental African Trypanosomiasis, Deborah Frenkel

Doctoral Dissertations

Loss of humoral immune competence in T. brucei-infected mice is associated with the apoptotic depletion of splenic transitional, marginal zone and follicular B cells as well as a depletion of CD8+ T cells. This occurs rapidly after infection and impairs responses to vaccine antigens in addition to responses to newly arising VSG antigenic variants, leading to uncontrolled parasite growth and death of the infected mice. Infection-induced B2 B cell and CD8+ T cell loss requires the presence of a novel population of natural killer (NK) cells and is mediated by a perforin-dependent process consistent with perforin- and …


Mechanisms Contributing To The Emergence Of Ranavirus In Ectothermic Vertebrate Communities, Roberto M. Brenes Aug 2013

Mechanisms Contributing To The Emergence Of Ranavirus In Ectothermic Vertebrate Communities, Roberto M. Brenes

Doctoral Dissertations

Ranaviruses have been linked to amphibian die-off events in ectothermic vertebrates worldwide. Differences in susceptibility and capacity of transmission among and within classes are poorly understood. My goal was to determine possible mechanisms influencing susceptibility to ranavirus infection in amphibian species and other aquatic vertebrate taxa, as well as the capacity of transmission between classes and the effects of amphibian community composition on ranavirus transmission. I tested 16 amphibian species from USA, Europe, and the pet trade, expanding an existing database developed by the Center for Wildlife Health to 35 amphibian species from 9 families. I also tested the susceptibility …