Matching Items (162)
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
Description
Major Depressive Disorder (MDD) is a common mental disorder that can affect individuals at nearly every stage of life. Women are especially vulnerable to MDD in part, from ovarian hormone level fluctuations. In this thesis, I focused on MDD using a rat model in middle-age to explore potential sex differences in response to a corticosterone (CORT) – induced depressive-like state. Estradiol (E2), a naturally occurring steroid sex hormone in humans and rats, is implicated in mood changes, which is especially prominent during the menopause transition. CORT, a stress hormone, was used to create a depressive-like state in middle-aged female (F) and male (M) rats with their gonads surgically removed. This produced the following independent treatment groups: Sex (F, M), CORT (vehicle = V ml/kg, C 40mg/kg), E2 (V 0.1 ml, E 0.3µg/0.1ml). CORT and E2 injections were injected daily, s.c) for 7 days before behavioral testing began and continued throughout the study when behavior was assessed. For my honor’s thesis, I focused on the social interaction test and elevated plus maze to investigate whether CORT enhanced social avoidance and anxiety, and whether E2 mitigated the CORT effects. In the social interaction test, three new behaviors were assessed (interacting, grooming, and immobility) to better understand exploratory and anxiety profiles of the rats, and these behaviors were quantified over two 5-minute periods in the 10-minute trial. These new quantifications showed that for the female rats, C+E and V+V enhanced the interaction with the novel rat significantly more than an inanimate object, which was not observed in the females given CORT only or E2 only. The males in all conditions showed a significant preference for side with the novel rat compared to the object, however no treatment differences were observed. In both sexes, the overall time spent interacting decreased in the second five minutes of quantification compared to the first five minutes. No effects were observed with grooming or immobility, in part from the high variability across rats. For EPM, female rats treated with CORT and E2 exhibited a lower anxiety index than compared to female rats given CORT only, indicating that E2 mitigated the depressive-like effects of CORT. Males showed no CORT or E2 effects. The result in part supported my hypothesis, as the CORT-treated females exhibited reduced socialization and E2 improved socialization in CORT-treated females, as this was seen in the F-C-E group. Interestingly, CORT failed to produce a depressive-like effect in males in both behavioral tests, which was an unexpected outcome. These results suggest that administration of E2 with CORT mitigated the depressive-like state created by CORT in female rats, however failed to produce these outcomes in males. The outcome of this work will give us insight into the potential mechanisms that may contribute to sex differences with MDD.
ContributorsSladkova, Sara (Author) / Conrad, Cheryl (Thesis director) / Amdam, Gro (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / School of Life Sciences (Contributor)
Created2024-05