Browsing by Subject "Oak wilt"

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    Applications Of Nanotechnology For Microbial Diagnostics To Combat Infectious Diseases
    (2024-03) Novi Thekkudan, Vinni
    Various pathogens cause disease outbreaks in plants, animals and humans that have led to fatalities and economic losses. To effectively prevent these outbreaks, disease surveillance and early diagnosis is crucial. While there are some standard detection methods used currently, they are expensive and suffer from long turnaround times that delay treatment and disease control actions. Since nucleic acid detection techniques are preferred as they offer target gene specific diagnosis, significant research has been directed to simplifying them for faster and more accurate identification. Several isothermal amplification methods have been explored for this purpose, among which loop mediated isothermal amplification (LAMP) offers a simple, cost-effective, and reliable approach for rapid onsite pathogen detection. This study discusses the design and optimization of a LAMP assay for the detection of the oak wilt fungus, Bretziella fagacearum, as the model organism. Oak wilt disease is a significant threat to oak (Quercus spp.) tree health in the United States and eastern Canada. Without management the disease may cause dramatic changes to natural and urban ecosystems. Early and accurate diagnosis is necessary for timely treatment. The LAMP assay developed for oak wilt takes 30 min to complete and shows 100% sensitivity and specificity. Recent studies have investigated colorimetric visualization of LAMP products for their adaptability to onsite microbial detection, but they suffer from reproducibility and varied perceptions of color change. Therefore, this study also discusses the development of a novel LAMP visualization method by exploiting the optical properties of gold nanoparticles (AuNPs) to overcome those challenges. Oligonucleotide-coated AuNPs (AuNP-oligos) hierarchically assemble on DNA networks in positive samples to form globular nanostructures, that settle into a visible red pellet upon inducing precipitation whereas, the negative samples do not show this. This LAMP assay coupled with AuNP-oligos visualization is a promising method for accurate and rapid molecular-based diagnosis in field settings.Additionally, other applications of nanomaterials in combating infectious diseases are also discussed. This includes the study of zinc oxide nanoparticle coated textiles for their antimicrobial activity against human bacterial and fungal pathogens, Pseudomonas aeruginosa, methicillin resistant Staphylococcus aureus, Klebsiella pneumoniae and Candida albicans.
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    Characterization of Injection Wound Damage Associated with Propiconazole Treatments of Northern Pin Oaks
    (2020-08) Feltmeyer , Alexandra
    Oak wilt, caused by Bretziella fagacearum, is one of the most destructive diseases affecting urban and rural oak trees in the Midwest USA. The disease is difficult to control due to the systemic movement of the pathogen through the vascular system of oak trees. Primary approaches used to control oak wilt include disrupting underground spread through root cutting and the prevention of wounding during the high-risk period that the insect vectors of the oak wilt fungus are active. Preventative or therapeutic treatment of oaks using systemic injection techniques are a more recently developed control approach used by arborists and urban foresters. Systemic injection into xylem vascular elements of woody plants, however, involves physical wounding to the lower stem or root crown. The ability of a tree to compartmentalize such damage may affect tree vigor or even a tree’s ability to survive after repeated treatments. This thesis summarizes results of research on compartmentalization of damage associated with systemic injection of propiconazole fungicides in northern pin oak in Anoka County, Minnesota.