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- All Subjects: Bexarotene
- All Subjects: Yeast
- All Subjects: Contaminant exposure sampling
- Creators: Marshall, Pamela
- Status: Published
The purpose of this work is to study aspects of calcium homeostasis in the model organism Saccharomyces cerevisiae, common yeast. Using luminometric techniques, the response of the yeast was monitored against a set of changes in the environment calcium abundance. The results indicate a complex response as both increase and decreases of external calcium induce elevations in cytosolic calcium concentrations.
Calcium is transferred across compartments by means of channels. In Saccharomyces cerevisiae, many of them have been identified; Cch1p-Mid1p, Vcx1p, Pmc1p, Pmr1p, and Yvc1p. Their participation in calcium homeostasis is well established. Observations of cytosolic calcium increase after a hypertonic shock are mainly associated with influx of ions from the environment though the Cch1p-Mid1p. This process is generally considered as driven by calcium concentration gradients. However, recent studies have suggested that the plasma membrane channel, Cch1p-Mid1p, may possess more sophisticated regulation and sensory mechanisms. The results of our experiments support these ideas.
We carried out experiments that subjected yeast to multiple shocks: a hypertonic shock followed by either a second hypertonic shock, a hypotonic shock, or a yeast dilution pulse where the solution volume increases by the calcium concentration has only a small change. The cytosolic calcium concentration of a yeast population was monitored via luminometry.
The main result of this study is the observation of an unexpected response to the combination of hypertonic and hypotonic shocks. In this case it was observed that the cytosolic calcium concentration increased after both shocks. This indicates that cytosolic calcium increases are not solely driven by the presence of concentration gradients. The response after the hypotonic pulse arises from more complex mechanisms that may include sensor activity at the membrane channels and the release of calcium from internal storages.
The purpose of this work is to study aspects of calcium homeostasis in the model organism Saccharomyces cerevisiae, common yeast. Using luminometric techniques, the response of the yeast was monitored against a set of changes in the environment calcium abundance. The results indicate a complex response as both increase and decreases of external calcium induce elevations in cytosolic calcium concentrations.
Calcium is transferred across compartments by means of channels. In Saccharomyces cerevisiae, many of them have been identified; Cch1p-Mid1p, Vcx1p, Pmc1p, Pmr1p, and Yvc1p. Their participation in calcium homeostasis is well established. Observations of cytosolic calcium increase after a hypertonic shock are mainly associated with influx of ions from the environment though the Cch1p-Mid1p. This process is generally considered as driven by calcium concentration gradients. However, recent studies have suggested that the plasma membrane channel, Cch1p-Mid1p, may possess more sophisticated regulation and sensory mechanisms. The results of our experiments support these ideas.
We carried out experiments that subjected yeast to multiple shocks: a hypertonic shock followed by either a second hypertonic shock, a hypotonic shock, or a yeast dilution pulse where the solution volume increases by the calcium concentration has only a small change. The cytosolic calcium concentration of a yeast population was monitored via luminometry.
The main result of this study is the observation of an unexpected response to the combination of hypertonic and hypotonic shocks. In this case it was observed that the cytosolic calcium concentration increased after both shocks. This indicates that cytosolic calcium increases are not solely driven by the presence of concentration gradients. The response after the hypotonic pulse arises from more complex mechanisms that may include sensor activity at the membrane channels and the release of calcium from internal storages.
Silicone wristbands consist of a porous surface with the potential to sequester organic contaminants in the environment. Their properties allow for them to be used as a novel sampling approach to assessing personal human exposure to environmental contaminants. The purpose of the study was to understand the effectiveness of silicone wristbands as sampling devices. This was addressed by identifying and quantifying pesticide recovery from exposed wristbands. Triplicate groups of wristbands were dosed with 37 persistent organochlorine or organophosphate pesticides and then extracted to estimate human exposure through recovery. Results suggest that silicone wristbands have the potential to absorb a number of pesticides and organic contaminants, although at varying rates and quantities. As more uptake and sequestration rates can be established, wristbands have the potential to serve as indicators of human exposure to a variety of pesticides and other chemical groups at trace amounts.
The ever-increasing importance of cancer and neurodegenerative diseases continues to grow as populations across the world are affected by death and aging. The vitamin A (RXR) and vitamin D (VDR) receptor pathways offer promising potential to aid in treatment of cancer and Alzheimer’s disease. This thesis discusses the potential application of novel analogs of Bexarotene (RXR agonist), MeTC7 (a new potent VDR antagonist), and vitamin D as possible therapeutics for cancer and Alzheimer’s disease.
To test this, Saccharomyces cerevisiae was utilized. This is a primary model used in most medicinal studies due to the resemblance to human cells. This study evaluates the effect of ferulic acid, concentrations on ultraviolet radiated Rad 1 (mutant) and HB0 (wild type) yeast cells. The yeast strains were grown in two different concentrations for ferulic acid and treated with long-wave UV light under 30 seconds, 45 seconds, and 60 seconds. It is observed that, Rad 1 had heavier growth in the presence of high concentration of ferulic acid after UV treatment than HB0. But, HB0 yeast had heavier growth in the presence of lower concentrations of ferulic acid after UV treatment. Ferulic acid concentrations of 1 mM can influence cell repair after UV application by mRNA expression during nucleotide excision repair and higher absorption of UV.