Physiology Commons^™

Mapk Survival Signaling In Melanoma, Matthew W. Vanbrocklin

Dissertations

Extracellular signals activate mitogen-activated protein kinase (MAPK) cascades potentiating biological activities such as cell proliferation, differentiation, and survival. Constitutive activation of MAPK signaling pathways is implicated in the development and progression of many human cancers, including melanoma. Mutually exclusive activating mutations in NRAS or BRAF are found in ∼85% of all melanomas resulting in constitutive activation of the MAPK pathway (RAS-BRAF-MEK-ERK-RSK). We have previously demonstrated that inhibition of this pathway with small molecule MEK inhibitors selectively induces apoptosis in human melanoma cells both in vitro and in vivo, but not in normal melanocytes. These results support the notion that the …

Molecular Analysis Of The Effects Of Atrazine On Xenopus Laevis Frogs, Ronald Edward Celestine

Dissertations

Atrazine, the most commonly used herbicide in the U.S., has been implicated as one of the factors that may be causing the worldwide decline of amphibians. First, I examined effects of atrazine on laboratory raised Xenopus laevis tadpoles, treated from 5 days post fertilization to NF stage 65/66 with a concentrationof 25 ppb of atrazine. This study showed no significant difference in body weight, length and metamorphic rate.

Second, I used DNA microarrays to examine mRNA expression levels of genes in atrazine treated and control Xenopus laevis tadpoles. I found significant changes in gene expression levels of 18 genes. These …