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(1 - 3 of 3)
- Title
- PRECISION DIAGNOSTICS AND INNOVATIONS FOR PLANT BREEDING RESEARCH
- Creator
- Hugghis, Eli
- Date
- 2021
- Collection
- Electronic Theses & Dissertations
- Description
-
Major technological advances are necessary to reach the goal of feeding our world’s growing population. To do this, there is an increasing demand within the agricultural field for rapid diagnostic tools to improve the efficiency of current methods in plant disease and DNA identification. The use of gold nanoparticles has emerged as a promising technology for a range of applications from smart agrochemical delivery systems to pathogen detection. In addition to this, advances in image...
Show moreMajor technological advances are necessary to reach the goal of feeding our world’s growing population. To do this, there is an increasing demand within the agricultural field for rapid diagnostic tools to improve the efficiency of current methods in plant disease and DNA identification. The use of gold nanoparticles has emerged as a promising technology for a range of applications from smart agrochemical delivery systems to pathogen detection. In addition to this, advances in image classification analyses have allowed machine learning approaches to become more accessible to the agricultural field. Here we present the use of gold nanoparticles (AuNPs) for the detection of transgenic gene sequences in maize and the use of machine learning algorithms for the identification and classification of Fusarium spp. infected wheat seed. AuNPs show promise in their ability to diagnose the presence of transgenic insertions in DNA samples within 10 minutes through colorimetric response. Image-based analysis with the utilization of logistic regression, support vector machines, and k-nearest neighbors were able to accurately identify and differentiate healthy and diseased wheat kernels within the testing set at an accuracy of 95-98.8%. These technologies act as rapid tools to be used by plant breeders and pathologists to improve their ability to make selection decisions efficiently and objectively.
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- Title
- Genetic And Genetic By Environment Effects On Tar Spot Resistance And Hybrid Yield In Maize
- Creator
- Trygestad, Blake
- Date
- 2021
- Collection
- Electronic Theses & Dissertations
- Description
-
The phenotype of any plant can be broken down into the three primary sources of variation, genetic (G), environment (E), and genetic by environmental interaction (GxE). Producers and researchers alike will harness repeatable G and GxE effects to maximize their resource efficiency. This study studied the G and GxE effects in the biotic stress of the fungi Phyllachora maydis and the environment patterns in advanced yield trial data. In rating 800 genotypes over two seasons, we genetically...
Show moreThe phenotype of any plant can be broken down into the three primary sources of variation, genetic (G), environment (E), and genetic by environmental interaction (GxE). Producers and researchers alike will harness repeatable G and GxE effects to maximize their resource efficiency. This study studied the G and GxE effects in the biotic stress of the fungi Phyllachora maydis and the environment patterns in advanced yield trial data. In rating 800 genotypes over two seasons, we genetically mapped and identified over 100 significant Single Nucleotide Polymorphisms (SNPs) associated with tar spot resistance using a genome-wide association study. We then conducted genomic prediction, which was 81.5% accurate for predicting tar spot severity within the location and 48% accurate in predicting disease resistance in a new environment. Also, using Genetic and Genotype x Environment (GGE) biplots, we investigated environmental patterns of nine locations in three maturity Zones in the advanced yield trials in the Michigan Yield Performance Trials. First, we identified two locations, one in the late and one in the mid maturity zone, with equal G and GxE effects and should be removed. Then, using a sliding window of year combinations, we analyzed the optimal number of replications needed across the three maturity zones. We determined that an average of three replications are needed to achieve 75% of the maximum repeatability across the zones.
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- Title
- Pathology at the neuromuscular junction in mouse models of spinal bulbar muscular atrophy
- Creator
- Poort, Jessica Erin
- Date
- 2014
- Collection
- Electronic Theses & Dissertations
- Description
-
Spinal bulbar muscular atrophy (SBMA) is a progressive, late onset neuromuscular disease that results in muscle weakness and atrophy, as well as motoneuron death in men. While pathology at the neuromuscular junction (NMJ) is noted in numerous neurodegenerative diseases, disease-related changes at the NMJ in SBMA have not been explored. Characterizing such changes is not only important for determining whether the NMJ has any role in the functional changes underlying motor dysfunction, but also...
Show moreSpinal bulbar muscular atrophy (SBMA) is a progressive, late onset neuromuscular disease that results in muscle weakness and atrophy, as well as motoneuron death in men. While pathology at the neuromuscular junction (NMJ) is noted in numerous neurodegenerative diseases, disease-related changes at the NMJ in SBMA have not been explored. Characterizing such changes is not only important for determining whether the NMJ has any role in the functional changes underlying motor dysfunction, but also in determining how such potential pathology at the NMJ develops as disease progresses. If for example, pathology emerges first at the NMJ followed by motoneuron death, then the NMJ offers future promise as a therapeutic target for preventing or reversing symptoms of SBMA before motoneurons are lost. We evaluated three different mouse models of SBMA, one overexpressing a wildtype androgen receptor (AR) exclusively in muscle fibers (so called "myogenic" model), a second which expressed the endogenous AR gene with the first exon of the human mutant AR gene "knocked in" (the so called "knock-in" model), and a final model that broadly expresses a full length human AR transgene harboring the SBMA mutation (the so called "97Q" model). Using both confocal microscopy and electron microscopy, I found that all three mouse models show a pathological fragmentation of the NMJ suggestive of functionally weakened synapses. Other changes at the neuromuscular synapse suggesting decreases in synaptic strength that were found in some but not all models include a decline in the number of docked vesicles ready for release in nerve terminals, a widening of synaptic clefts, simplified postsynaptic folds, and an abnormal accumulation of synaptic vesicle and neurofilament proteins. Retrograde axonal transport of endosomes was also characterized in the 97Q model using live imaging confocal microscopy. Despite previously published data, I found no evidence for a disease-related defect in retrograde transport in the 97Q model. The strikingly abnormal morphology of NMJs in all three models raises the possibility that synaptic function is impaired. Such synaptic dysfunction may contribute to or underlie the impairments in motor function associated with SBMA.
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