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Malignant melanoma arises from a genetic defect in pigment producing cells known as melanocytes. Melanoma is not the most common type of skin cancer; however, it is the deadliest type. The ability of malignant melanoma cells to metastasize poses a great health risk. Previous studies have shown that highly aggressive human melanoma cells (most likely to metastasize) unlike poorly aggressive melanoma cells (least likely to metastasize), express markers associated with endothelial and epithelial cells and form vascular-like networks, in a process called vasculogenic mimicry (VM). The objective of this study was to determine the expression levels of the tyrosine kinase receptor EphB4 and its ligand ephrin-B2 in highly aggressive human melanoma cells compared to poorly aggressive human melanoma cells. PCR primers targeting the EphB4 and ephrin-B2 gene were designed and PCR was performed. Our results indicate that EphB4 is expressed by both highly and poorly aggressive human melanoma cells whereas ephrin-B2 displays an increased level of expression in highly aggressive human melanoma cells. Future research aims are to understand the functional significance of this receptor/ligand pair and its role in mediating melanoma vasculogenic mimicry.
Constructed wetlands are an economical method to treat wastewater. Wetland plants may assist in removing chemicals and wetland microorganisms decompose organic matter in the water. Furthermore, constructed wetlands may serve as habitat for a variety of species, such as birds, reptiles, and amphibians. However, constructed wetlands many contain potentially pathogenic enteric organisms from the wastewater or from animal fecal waste. Coliforms are traditionally used as indicators of fecal and enteric pollution, and are detected by culture-based techniques. Molecular methods such as Polymerase Chain Reaction (PCR) and quantitative PCR (qPCR) are faster and detect organisms that culturing cannot. In this study, the presence and abundance of fecal coliforms, other coliforms, and enteric bacteria (e.g., Escherichia coli, Salmonella sp., Shigella sp.) were estimated in a constructed urban wetland. Water samples were taken from a wetland pond and an adjacent canal, and used to detect target bacteria using traditional culturing and qPCR of functional genes lacZ, lamB and uidA. Traditional culturing and qPCR assays both detected the three groups of organisms; however, qPCR detected a higher abundance of coliforms and enteric bacteria, especially in the pond, than would be predicted based on culturing experiments. This suggests that a significant number of coliforms and enteric bacteria are present in constructed wetlands that resist culturing. Moreover, qPCR using functional genes was better at detecting groups of enteric organisms rather than just single species. This allows for greater numbers of organisms to be detected. qPCR is therefore considered a better method for monitoring indicator organisms in constructed wetlands compared to culturing methods.
Different biogeographic factors may influence the richness of lichen and tree assemblages found on islands within boreal lakes. To examine the relative importance of island area, insularity and habitat for shaping these richness patterns, we surveyed lichen and tree species on islands of the Boundary Waters Canoe Area Wilderness in northern Minnesota, USA. We hypothesized that dispersal would be a more important limiting factor for trees, whereas lichen richness would be limited primarily by habitat. Thirty islands were sampled during a one-week study in September-October 2009. For each island we measured island area, distance from lakeshore, and counted the number of habitats. A total of 51 lichen and 15 tree species were found. Lichens occurred on every island and ranged between 2 and 28 species per island. Trees were found on just 13 of the 30 islands and their richness ranged from 1-12 species. Regression analysis and structural equation modeling showed that habitat number and island size were the principle factors affecting the richness of both taxa. Insularity had a small effect on lichen richness and no effect on tree richness. When trees and lichens were examined separately, island area influenced tree richness more than did habitat, whereas lichen richness was most strongly influenced by tree richness.
The following chapters have sent in officer slates for 2012-2013. Officers are listed in the order of President, Vice President, Secretary, Treasurer, Historian, and Faculty Advisor unless otherwise noted. The chapters are listed alphabetically by Greek name. Please submit new slates, changes and corrections to Lori.Kelman@montgomerycollege.edu.