Genetics and Genomics Commons^™

Resistance To Double-Stranded Rna (Dsrna) In Colorado Potato Beetle (Leptinotarsa Decemlineata Say): Genetic And Molecular Insights, Swati Mishra

Doctoral Dissertations

Double-stranded RNA (dsRNA) insecticides delivered through transgenic and non-transgenic means have been approved for commercialization in the US. As with other insecticides development of insect resistance is expected, necessitating the implementation of an Insecticide Resistance Management (IRM) framework for their long-term use. Laboratory-selected insect resistance strains can provide useful insights for an effective IRM plan. The Colorado potato beetle (CPB) is the target pest for the first commercial dsRNA foliar spray, making it an ideal model to study dsRNA resistance. In this dissertation, we studied the previously described CEAS 300 strain of CPB that exhibits >11,100-fold resistance against V-ATPase subunit …

Evolution And Phylogeny Of The Parasitoid Subfamily Phasiinae (Diptera: Tachinidae), Jeremy Daniel Blaschke

Doctoral Dissertations

The first molecular phylogenetic analysis of the agriculturally important parasitoid subfamily Phasiinae (Diptera: Tachinidae) is presented, estimated from 128 worldwide taxa (80 genera) and approximately 7.6 kilobases of nuclear data. Special emphasis is placed on taxa with controversial taxonomic placement. The resultant phylogenetic tree is used to reconstruct ancestral character states, trace the evolution of significant adaptive traits within the Tachinidae, and test hypotheses about the classification of Phasiinae. Subfamily placements of the taxa Eutherini, Epigrimyiini, Litophasia, Strongygastrini, and Parerigonini are confidently resolved, the former three within Dexiinae and the latter two within Phasiinae. Due to sparse molecular evidence, …

Characterization Of The Role Of Alpha-Arylphorin In The Heliothis Virescens Midgut Response To Cry1ac Toxin From Bacillus Thuringiensis, Jerreme Jamael Jackson

Doctoral Dissertations

Homeostasis of the intestinal epithelium in Heliothis virescens is mediated by the proliferation and differentiation of multipotent intestinal stem cells (ISCs) that lie adjacent to the basal lamina. In response to extrinsic and intrinsic signals, ISC proliferation and differentiation promotes epithelial growth and regeneration following the loss of integrity. We tested the in vivo effects of the ISC mitogen, a [alpha]-arylphorin, on ISC proliferation and the morphological changes of the midgut during larval development. Additionally, we examined how these changes affected the intestinal epithelium response to Cry1Ac toxin from Bacillus thuringiensis. Histological and in vitro evidence supported two distinct …

Trends In Borrelia Spp. Prevalence In Ixodes Spp. Ticks From The Southeastern Coastal United States, Lauren Paul Maestas

Masters Theses

The Lyme borreliosis (LB) cycle, involving Ixodes scapularis and Borrelia burgdorferi sensu stricto (Bbss), is well documented in the northeastern US, where LB is becoming increasingly prevalent. In coastal North Carolina, I. affinis has been shown to have a higher incidence of Bbss than I. scapularis. My objectives were, to assess changes in prevalence of Bbss in Ixodes spp. along a transect from Virginia to Florida, and to assess the value of dogs and mesomammals as sentinels for spread of Borrelia burgdorferi sensu lato.

Ixodes spp. were collected at sites from 37.4^o N to 30.0^{o …}

Molecular Systematics Of The Subfamily Phasiinae (Diptera: Tachinidae), Jeremy Daniel Blaschke

Masters Theses

The subfamily Phasiinae (Diptera: Tachinidae) is composed of obligate endoparasitoid flies that attack heteropteran insects, many of which are important agricultural pests. To lay a foundation for future studies in phasiine life history and their potential for use as biological control agents, the phylogenetic relationships within Phasiinae were explored using nucleotide sequences of two genes, CAD and LGL. A total of 63 taxa for CAD and 73 taxa for LGL were included in the analyses, representing 58 genera. Maximum likelihood inference methods were employed to reconstruct phylogenetic relationships in separate analyses of each gene and in a combined dataset. Phylogenetic …