March 21, 2014

Hannah Holicky "14Abstract:

Temperature of an environment has a major impact on the organisms that live within the environment; this is especially notable in ecototherms. Cricket song is greatly affected by temperature; particularly an increase in temperature increases the speed and frequency of song components. Females receiving a male’s song could potentially receive a different message depending on the temperature at which the male is singing. Males were recorded singing at a hot (28o C) and cold (22o C) temperature. A choice test was conducted using a glass terrarium sectioned in to preference zones to evaluate females’ preference towards male songs. Females were able to move freely throughout the terrarium while recordings of a male’s hot and cold songs were played. Time females spent in each preference zone was recorded and evaluated. However, there seemed to be no clear female preference for male songs of different temperatures. Other factors such as mating experience of the female, and maintenance of a truthful signal by the male may be cause for this result.

Effect of Teplizumab Treatment on C-Peptide Response in Patients with New-onset Type1 Diabetes

Rachel Henrickson '14Abstract:

Type 1 diabetes occurs when a person’s own immune system destroys the insulin-producing cells of the pancreas (beta cells). Without sufficient levels of insulin, the body cannot move glucose into the cells of the body, and blood glucose levels will drastically increase. Herold et al hypothesized that teplizumab could slow disease progression of type 1 diabetes. The drug would preserve beta cell function and help stabilize blood glucose levels. New-onset type 1 diabetes patients were treated with teplizumab, an Fc receptor non-binding anti-CD3 monoclonal antibody. 58 participants diagnosed within 4-12 months before the study began were randomized in a placebo-controlled double-blind study at four academic centers in the USA. They received a 14-day course of either intravenous teplizumab or saline. Insulin production was measured by testing C-peptide levels in the blood. C-peptides are a byproduct of insulin and offer a way of determining insulin produced without the confusion of artificial insulin present in the bloodstream. Herold’s hypothesis was supported. C-peptide levels were 17.7% higher in the teplizumab-treated group 12 months after treatment. Also, the teplizumab group required less exogenous insulin, and treatment benefits were larger for younger individuals. The study suggests that deterioration in insulin secretion may be affected by immune therapy with teplizumab after the new-onset period.

Response of Daphnia Heart Rate to Predator Kairomones

Lance Hentges '14Abstract:

The purpose of this study was to examine the short-term effects of predator kairomones and alarm cues on Daphnia pulicaria, as measured by change in heart rate. Additionally, differences between primary and secondary exposure to the kairomone-alarm cue solution were measured to determine if there was a learned behavior change after the initial incident. Samples of Daphnia were obtained from Square Lake. These organisms were cultured such that only clone progeny formed from a single isofemale. They were also maintained for a length of time great enough to allow any kairomones that may have been present from the initial sample to completely break down. Clones of a specific size (1.3mm to 2.2mm) were selected and their heart rate was monitored before and after treatment; once 48 hours had passed the secondary exposure treatments were carried out. In order to mimic a common threat to Daphnia, the kairomone-alarm cue solution was made from live Pimephales promelas, a species of minnow also found in Square Lake. Heart rates were recorded using a high-resolution video camera, and counted by scrubbing through frames of the video recording. A paired t-test was used to measure the significance between the individual groups. The data suggest that there is no significant change in heart rate due to the kairomone-alarm cue solution. Percent change in heart rate was also calculate, and using an additional paired t-test, change between primary and secondary exposure was assessed. These results were also did not show statistical significance either, indicating that a learned response to kairomones-alarm cues was not evident in this experiment.