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Full-Text Articles in Molecular Biology

Engineering Cry4aa For Toxicity Against The Soybean Aphid, Aphis Glycines Matsumura, Benjamin Robert Deist Jan 2015

Engineering Cry4aa For Toxicity Against The Soybean Aphid, Aphis Glycines Matsumura, Benjamin Robert Deist

Graduate Theses and Dissertations

Soybean aphid poses a significant threat to soybean agriculture in North America. Current management strategies are heavily dependent on chemical insecticides, which while presently effective, may have negative side effects. Bt toxins have been successfully used in various transgenic crops for almost 20 years to manage lepidopteran and coleopteran pests. However, this strategy has not been used in the management of aphids and other hemipterans due to their low susceptibility to Bt toxins, potentially arising from a lack of binding to the hemipteran gut. To circumvent this limitation in soybean aphids, a phage display library was screened in vivo against ...


Modification Of The Bt Toxin Cry4aa For Improved Toxin Processing In The Gut Of The Pea Aphid (Acyrthosiphon Pisum), Michael Allen Rausch Jan 2014

Modification Of The Bt Toxin Cry4aa For Improved Toxin Processing In The Gut Of The Pea Aphid (Acyrthosiphon Pisum), Michael Allen Rausch

Graduate Theses and Dissertations

Aphids are sap-sucking insects (order: Hemiptera) that cause extensive damage to a wide range of agricultural crops. Our goal is to produce a "designer" toxin based on naturally occurring insecticidal crystalline (Cry) toxins produced by the soil-dwelling bacterium Bacillus thuringiensis for use against the pea aphid, Acyrthosiphon pisum. On the basis that activation of the Cry4Aa protoxin could be a rate-limiting factor contributing to the relatively low aphicidal activity of this toxin, we introduced cathepsin L and cathepsin B cleavage sites into Cry4Aa for rapid activation and generation of the active toxin in the aphid gut environment. Incubation of modified ...


Investigation Into The Mechanism Of Salicylate-Associated Genotypic Antibiotic Resistance In Staphylococcus Aureus, Nada Salah Helal Jan 2012

Investigation Into The Mechanism Of Salicylate-Associated Genotypic Antibiotic Resistance In Staphylococcus Aureus, Nada Salah Helal

Graduate Theses and Dissertations

Growth of Staphylococcus aureus with the NSAID salicylate increases phenotypic resistance (SAPAR), and the frequency at which heritable resistance occurs to various antibiotics (SAGAR). This study describes the effect of salicylate on heritable and phenotypic resistance to a set of antibiotics for laboratory and multi-drug resistant strains of S. aureus and investigates the link between resistance and SAGAR. Drug gradient plates were used to determine phenotypic resistance to antibiotics targeting DNA replication, transcription, translation and the cell wall in the presence or absence of salicylate. To measure heritable resistance, mutation frequencies were determined for each antibiotic in the presence and ...