Undergraduate - Anthropology, College of Liberal Arts and Sciences
Research/Activity: Determining Bone Utility and Effectiveness as Tools: Termite Extraction at Lake Manyara, Tanzania during the Dry Season in Tanzania
Faculty Sponsor: Dr. Charles Musiba – College of Liberal Arts and Sciences
Taphonomic evidence of bone surface modification for tool use by early hominins was recently recognized at Swartkrans in South Africa by Backwell and d’Errico; however, very little taphonomic research of this type has been conducted in East African Pliocene sites.
During the CU Denver Tanzanian field school in anthropology at Laetoli, we conducted experiments to test whether bones recovered from recent death assemblages could be modified and used for termite fishing at mounds near Lake Manyara. Bone tools were modified and used to puncture termite mounds, thus creating a use wear pattern that would be indicative of tool use and compared with fragmented fossil bones found at Laetoli. A scan electron microscope (SEM) was used to examine bone surface modification associated with tool use (polishing and striations) that match those reported from Swartkrans as possible evidence of Australopithecines early bone modification and tool use for termite fishing.
We report that to achieve the greatest number of termites, in terms of calorific intake, with the least amount of energy expended most likely occurred shortly after the rain season or at locations where mounds are in close proximity to water sources.
Undergraduate - Geography-Earth Science, College of Liberal Arts and Sciences
Research/Activity: Isolation and Characterization of Cadmium-Resistant Bacteria
Faculty Sponsor: Dr. Timberley Roane - College of Liberal Arts and Sciences
The bacterium Pseudomonas sp. S8A, initially isolated from a mine tailing-contaminated soil, demonstrates a high degree of resistance to cadmium toxicity, up to 200 ppm soluble cadmium. In characterizing this bacterium’s resistance to cadmium, several mechanisms of metal detoxification were identified. In response to cadmium, Pseudomonas sp. S8A produces a cadmium-binding exopolymer and a cadmium-binding biosurfactant, both known among other metal-resistant bacteria. However, unique to Pseudomonas sp. S8A is a newly identified genetic mechanism possibly partially accounting for the high degree of cadmium resistance. This mechanism, identified as part of the Cpx cell stress response system, has not before been identified in environmental bacteria, such as Pseudomonas sp. S8A.
The specific objectives of this UROP project were two-fold: (1) characterize cadmium-resistant bacteria from the Pennsylvania mine site in Colorado; and (2) use the polymerase chain reaction (PCR), a molecular method used to identify specific genes, to screen for the presence of the Cpx stress response system in the cadmium resistant bacteria. The isolation and characterization of cadmium-resistant bacteria is of great interest due to their potential use in metal detoxification and remediation of contaminated sites.
Graduate Student - Landscape, Architecture & Urban Design, College of Architecture and Planning
Research/Activity: Hybridscape: A Proposal for Wynkoop Street and Denver Union Station
Faculty Sponsor: Mr. Fred Andreas - College of Architecture and Planning
Denver Union Station was once the gateway to the city and remains one of the finest examples of a major 19th century transportation hub. Our objective in this studio project is to provide sustainable urban design guidance for the renaissance of Union Station and the Wynkoop Street corridor between Cherry Creek and Coors Field, creating a major public space in the heart of the city.
HYBRIDscape is a vision that bridges the gap between the street’s historic past and a sustainable future. Our project envisions a sustainable, walkable, and transit-served urban neighborhood that serves as a gateway to Lower Downtown. As the station once again becomes the region’s major transportation hub, the project transforms parking lots and the historic street in front of the station into a pedestrian-friendly plaza.
The design creates a flexible space that handles thousands of daily commuters, special events and sports crowds, and also provides more intimate spaces, manages storm water, generates power for the neighborhood, and highlights native plants, natural processes and local history. The project integrates urbanism with high-performance buildings and high-performance infrastructure as a means to create potential: for architecture, for humanity, and for a sustainable future.
Graduate Student - Cell Biology, Stem Cells, and Development, AMC Graduate School
Research/Activity: Misregulation of Dlx5/6 in Hand2 Mutants Leads to Loss of Tongue
Faculty Sponsor: Dr. David Clouthier - School of Dental Medicine
Lower jaw development is orchestrated by signaling cascades that are regulated temporspatially, and are refined through permissive and inhibitory signals. We have previously shown that endothelin-A receptor signaling is crucial for establishing the identity of cranial neural crest (CNC) cells in the mandibular arch through a mechanism that involves Dlx5 and Dlx6 (Dlx5/6). Dlx5/6 induce expression of Hand2, a basic helix-loop-helix transcription factor.
Little is known about the function of Hand2 in mammalian facial development because Hand2-/- embryos die by embryonic day (E) 10.5 from vascular failure. To circumvent this lethality, we created a conditional targeted Hand2 mouse line using a Cre-loxP approach. Using the Wnt1-Cre mouse line, we deleted Hand2 within all CNC cells.
We find that Hand2 conditional knockout mice exhibit facial defects that include mandibular hypoplasia and loss of tongue (aglossia). Aglossia is preceded by aberrant maintenance of Dlx5/6 expression in the disto-oral mandibular archmesenchyme. In vitro studies show that Hand2 represses the Dlx5/6 pharyngeal arch-specific enhancer. Thus, Hand2 normally ensures normal tongue development by repressing Dlx5/6 expression within the disto-oral mandibular arch. In the absence of Hand2, Dlx5/6 expression is maintained and ectopically activates an osteogenic program at the expense of a tongue development program.