Frank G. Brooks Award Winners

First Place

Karen Burwinkel

Cytochrome P4501 A1 and arsenic in benzo(a) pyrene-induced carcinogenesis

The environmental pollutants arsenic and bonzo(a)pyrene (BaP) are well-known human carcinogens commonly found together in substances such as cigarette smoke Arsenic is addressed as a non-mutagenic co-carcinogen, with the potential to enhance the effects of mutagens such as BaP, although the mechanisms remain unclear. BaP exerts its carcinogenic effects by leading to the formation of DNA adducts, resulting in DNA replication errors and subsequent mutations. Detoxication of BaP in the liver is a multi-step process requiring several enzymes, notably cytochrome P4501 A1 (CYP1A1). In this study we examined the impact of arsenic on the enzyme CYP1A1 at different cellular levels, utilizing zebrafish (Danio rerio) as a model species. Experimental procedures included the EROD assay to measure enzymatic activity, SDS-PAGE/immunoblotting to quantify existing protein, ad quantitative PCR to determine transcriptional changes. CO-exposure of arsenic and BaP led to significant decreases in CYP1A1 protein levels and CYP1A1 enzyme activity when compared to those of BaP alone. The effect is likely transcriptional, as CYP1A1 mRNA levels decrease as a result of exposure to both arsenic and BaP. Experimental evidence suggests arsenic alters typical CYP1A1 activity in the presence of BaP. However, the outcome may lead to a diminished capacity for BaP-induced carcinogenesis.

Third Place

Andrew Jones

The Impact of influenza and respiratory syncytial virions on human natural killer cells

The purpose of this work was to analyze the interaction between human natural killer cells (NK cells) and virion particles. Direct immuno-modulation of NK cells by virions is a novel idea and will enhance the understanding of host-viral interactions. The interleukin (IL)-2-dependent NK cell line NK-92 was established in cell culture. Expression of immunologically relevant cytokine and cell surface molecules by the NK-92 cells was characterized by real-time polymerase chain reaction (RT-PCR) following one hour exposure to either UV-inactivated influenza A virus or UV-inactivated human respiratory syncytial virus (HRSV). Compared to untreated cells, virion exposure altered the cytokine expression levels of several genes by at least 2-fold. Compared to influenza virus, RS uniquely promoted an allergic inflammatory response by boosting IL-13, IL-1 receptor, IL-5, and IL-6 expression. Both virins altered colony stimulating factor 2 (CSF-2), SPP1 phosphoprotien, and tumor necrosis factor ligant TNFSF4 expression. These results indicate that virion components directly modulate human NK cell activity, which may be an important determinant of the outcome of viral infection. This is especially relevant for RSV, which is linked to the development of allergic inflammatory responses. Ongoing research will focus on identifying the virion components and cell surface receptors responsible for immunomodulation.

Christina Nichols

Human T cell imunomodulation by Cat’s Claw (Unicaria tomentosa) extract

Cat’s Claw (Unicaria tomentosa) extract has been used medicinally by the indigenous people of South and Central America to treat may ailments including arthritis, cancer and viral infections. This wide medicinal application indicates that the active compounds in Cat’s Claw extract have both immunostimulatory and immunosuppressive properties. To explore this duality, human CEM-1 T cells were cultured in 1% Cat’s Claw extract for a long-term period of 2 weeks and a short-term period of 24 hours. The T cells were then treated with either an optimal stimulatory does or a suboptimal non-stimulatory does of mitogen (PHA). The ability of Cat’s Claw extract to boost a sub-optimal T cell response (as would be useful for cancer therapy) and inhibit an inflammatory T cell response (as would be useful for arthritis therapy) will be determined by analyzing cytokine expression levels by real time polymerase chain reaction (RT-PCR) assay. Immunomodulation by Cat’s Claw extract will be determined by comparison of cytokine expression in T cells treated with Cat’s Claw on the human immune system and may lead to novel therapeutic treatments for a wide variety of human diseases.

John C. Johnson Award Winners

First Place

Elizabeth Droessler

Impact of leaves from invasive Amur honeysuckle on the development and fitness of wood frog tadpoles

Changes to pond and stream water chemistry from leaf toxins (tannins and phenolics) of the invasive Amur honeysuckle (Lonicera maackii) shrub can impact the development and fitness of larval amphibians. We examined the digestive efficiency of Wood Frog (Rana sylvatica) tadpoles, and the fitness (performance and energetics) of metamorphs raised under varying concentrations of leaf “teas” from: 1) Amur honeysuckle, 2) natural hardwood leaves, and 3) a pure water control. Our initial results suggest that tadpole digestion and metamorph fitness are reduced in frogs raised in invasive plant leaf teas compared to natural leaf teas or pure water.

Third Place

Brittany Muench

Degradation of urea by cave microorganisms through bioremediation

When humans camp or explore caves, under some circumstances, they cannot remove the urine they excrete due to safety concerns. In dry, desert caves this can have a negative effect on the subterranean environment and its microbial inhabitants. Urea, the major component of urine, can be broken down into other compounds such as ammonia, nitrate, nitrite, and nitrogen gas through various pathways of the nitrogen cycle. This introduces a significant nitrogen source into the starved environment of the cave system. We have isolated cave microorganisms capable of carrying out urine bioremediation in these environments, breaking down urea into nitrous oxide and nitrogen gas which are not usable. Our results demonstrate the breakdown of urea to ammonia, nitrate, and nitrite under aerobic conditions. Under anaerobic conditions, urea must be pretreated with urease. Our results suggest that there are microbial species, present in the cave system, that are capable of doing urine bioremediation as part of a consortium. Therefore, exogenous microorganisms do not have to be introduced to the cave system for bioremediation of urea. As a result, the urine may be disposed of in the caves with pre-treatment, limiting the adverse effects it could have on the environment.