Matching Items (212)
Description
Agrobacterium tumefaciens has the ability to transfer its tumor inducing (Ti) plasmid into plant cells. In the last decade, agroinfiltration of Nicotiana benthamiana plants has shown promising results for recombinant protein production. However, A. tumefaciens produce endotoxins in the form of lipopolysaccharides (LPS), a component of their outer membrane that can induce organ failure and septic shock. Therefore, we aimed to detoxify A. tumefaciens by modifying their Lipid A structure, the toxic region of LPS, via mutating the genes for lipid A biosynthesis. Two mutant strains of A. tumefaciens were infiltrated into N. benthamiana stems to test for tumor formation to ensure that the detoxifying process did not compromise the ability of gene transfer. Our results demonstrated that A. tumefaciens with both single and double mutations retained the ability to form tumors. Thus, these mutants can be utilized to generate engineered A. tumefaciens strains for the production of plant-based pharmaceuticals with low endotoxicity.
ContributorsHaseefa, Fathima (Author) / Chen, Qiang (Thesis director) / Mason, Hugh (Committee member) / Hurtado, Jonathan (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Fumonisins are fungal metabolites found in corn and cereals. Fumonisins pose health risks, including suspected carcinogenicity, yet their mechanism of toxicity remains unclear. While modifications in the human gut microbiome can impact host health, the effects of fumonisins on the microbiome are not well understood. Thus, our study aimed to assess a possible dose-response relationship between fumonisin B1 (FB1) and the gut microbiome. We utilized in vitro anaerobic bioreactors with media simulating most of the nutrients in the human large intestine, inoculated them with fecal samples from 19 healthy adults and treated them with FB1 at concentrations of 0, 10, 100, and 1000 ppb. Analyses of bioreactor headspace revealed declining methane production over time, possibly influenced by the addition of dimethyl sulfoxide (DMSO). Significant differences in acetic acid production were observed in 10 ppb reactor (Day 2) and 100 ppb reactor (Day 8) when compared to 0 ppb control. Microbiome analysis showed minimal shifts in microbial relative abundances during FB1 treatment, except for Desulfovibrio desulfuricans C at Day 8 when compared between 0 ppb and 10 ppb as well as 10 ppb and 1000 ppb at Day 16. Alpha diversity analyses indicated significant differences in observed features within bioreactors of different treatments, with some variation in Faith’s Phylogenetic Diversity between the 0 ppb and 10 ppb bioreactors. Beta diversity analyses, however, revealed no significant differences between bioreactors. Overall, our findings suggest no clear dose-response relationship between FB1 treatment and gut microbiome composition/functions. The presence of DMSO may have obscured potential effects. This research will help contribute to our understanding of mycotoxicity influence on the human gut microbiome.
ContributorsSanchez Carreon, Aurely (Author) / Krajmalnik-Brown, Rosa (Thesis director) / Cheng, Qiwen (Committee member) / Barrett, The Honors College (Contributor) / School of Molecular Sciences (Contributor)
Created2024-05