Life Sciences Commons^™

Diverse Community Of Arsenic Resistant Bacteria Display Arsenate Reducing Capabilities, Stephanie Maeda

Undergraduate Honors Theses

Naturally found in soil and water environments arsenic is toxic to many organisms, carcinogenic to humans, and poses a significant public health risk. Yet communities of bacteria found thriving in arsenic ridden environments have evolved mechanisms to tolerate and exploit both oxidation states of this heavy metal (arsenite and arsenate). As the site of an old arsenic mine, Black Mountain Open Space Park in San Diego, California has yielded concentrations of arsenic in the soil between 111-14,800 ppm. Exceeding average arsenic soil concentrations and levels considered safe in the environment by the World Health Organization, we sought to characterize the …

Bubble Stream Production By Belugas (Delphinapterus Leucas), Megan Slack

Theses

Bubble stream production in belugas has been poorly characterized and its function is not well understood. I examined behavioral states when producing bubble streams (“bubbling”), and when bubbling calls, to determine whether bubbling was significantly associated with a particular call category or behavioral state. Using 19 hours of video and audio recordings collected over a two-day period, I quantified bubble streams of a 4-month old calf and an unrelated adult female housed together. Based on the overall activity budgets and pool of vocalizations for both animals, I calculated the expected counts of bubble streams with and without vocalizations, assuming that …

The Physiological Effects Of Exercise On California Yellowtail (Seriola Dorsalis) White Muscle, Julie Giannini

Undergraduate Honors Theses

California yellowtail (Seriola dorsalis) is a species of ray-finned fish that demonstrates a significant increase in muscle mass in response to sustained exercise at optimal swimming speed. In this study, three groups of yellowtail have been analyzed for a 6-month period to determine if the length of exercise affects white muscle fiber development and if these changes persist when the exercised fish have been returned to a normal “resting” condition. Gene analysis was performed to test if MyoD, a myogenic regulatory factor, was upregulated in response to exercise. To test these questions, the groups compared included a control …

Effect Of Adult Chemical Cues On Molting Of Fiddler Crab Megalopae In Low Salinity Seawater, Sydney Rilum

Undergraduate Honors Theses

Three species of fiddler crabs, Uca minax, U. pugnax, and U. pugilator, are commonly found in estuaries along the Atlantic coast, each with distinct adult habitats differing in salinity and sediment grain size. Prior research has found evidence for larvae exhibiting selective settlement; however, the degree to which and the method by which they choose their species-appropriate habitat to settle in is still unknown. Additionally, a recent study determined that chemical cues from adult crabs stimulate molting in field-caught fiddler crab megalopae, as previously determined in lab-reared megalopae; however, in 35 ppt seawater, few U. minax molted. …

Daphnia: A Possible Way To Combat A Deadly Amphibian Pathogen, Taylor Thomas

Undergraduate Honors Theses

Globally there is a biodiversity crisis, with many groups of species threatened with extinction due to changes in the environment and human impacts. Amphibians are one such group and according to the IUCN, over 30% of amphibians are threatened by extinction. There are many factors have that can explain the decline of amphibians including pollution, habitat loss, climate change and disease. One factor is chytridiomycosis, an emerging infectious disease caused by the chytrid Batrachochytrium dendrobatidis. The chytrid enters the keratinized skin of the amphibian and asexually reproduces, where it disrupts host functions, often leading to host death.

Due to …

Investigation Into The Mechanism Of Ion Transport In Rio Negro Characiformes, Vineza D. Reduta

Undergraduate Honors Theses

Four fish species within the Characiform Order [(Rosy tetras (Hyphessobrycon rosaceus), Serpae tetras (Hyphessobrycon eques), Emperor tetras (Nematobrycon palmeri) and Penguin tetras (Thayeria obliqua)] are native to the ion-poor, acidic waters of the Rio Negro. In this paper, we focus on Wood’s revised Na⁺/NH₄⁺ exchange model to gain better insight into the mechanisms of ion transport within the Characids. We exposed each species to two experimental treatments: (i) 1mM ammonia (high external ammonia [HEA]), to test coupling of Na⁺ uptake and ammonia excretion, and (ii) 100μM Acetazolamide …

The Effects Of Sustained, High-Velocity Exercise On Gene Expression In California Yellowtail (Seriola Lalandi), Kelli Hatter

Undergraduate Honors Theses

California Yellowtail muscle fibers have been observed to exhibit two drastically different development patterns resulting from the speeds at which they are exercised. When fish are exercised at a moderate rate their epaxial fast-twitch muscle fibers grow in diameter—hypertrophy; when they are exercised at a fast speed, more new epaxial fast-twitch muscle fibers are produced—hyperplasia. To determine the underlying reason for this difference in muscle development, my summer research project and honors thesis exercised fish at: fast, moderate, and control speeds for a sustained amount of time to determine what is happening on a cellular level to cause the observed …