Biology Seminars (2009)

Abstract. The polar bear (Ursus maritimus) has become a highlighted species in the effects of climate change due to its strong dependence on ringed seals (Phoca hispida) and, thus, annual sea ice on which it hunts seals. Polar bears have adapted to living in the Arctic region by hyperphagic feeding during periods of high densities of ringed seals and accumulating fat deposits to support fasting during low food availability. However, this top predator is facing population decline and perhaps is becoming a threatened species due to climate change and pollution.

Abstract. Freshwater Eustigmatophyceae are a group of microalgae that are considered rare and of low diversity, with only a few genera and species in a single order. Some Eustigmatophyceae produce fatty acids that are important nutrients for aquaculture, as well as human food consumption. In addition, some Eustigmatophyceae produce hydrocarbons that may be useful in biofuel production. In our studies of the diversity of coccoid algae from Itasca State Park, Minnesota, we discovered several isolates that we tentatively identified as Eustigmatophyceae. Preliminary molecular characterization indicated that these isolates were highly diverse and probably represented species new to science. In this study, we examined fifteen of the Eustigmatophyceae isolates from Itasca State Park using DNA sequence analysis of the plastid rbcL gene. Phylogenetic analyses of these sequences strongly supported Eustimatophyceae as a monophyletic group and indicated two distinct lineages among our isolates within Eustigmatophyceae. The diversity among these isolates is high relative to diversity within outgroup classes. Our results suggest that many of these isolates represent new genera and species. We can also infer the existence of at least two orders in the Eustigmatophyceae, based on the presence of two distinct lineages in the class. In addition to the taxonomic implications, this study will aid in the selection of isolates for further characterization of fatty acids and hydrocarbons, or as part of a regenerative life support system during extended space missions.

Abstract. MicroRNA is a small species of messengerRNA that has gene silencing properties. Although not all of the mechanisms that power microRNA are understood, it is widely agreed that microRNA plays an important role in biological processes that, when altered, can cause human disorders that involve increased transcription or rapid cell growth. If the mechanisms and target selections of microRNA can be extensively understood, there is great potential for this species to be used in the treatment of the disorders in which they are involved.

Abstract. Caffeine is used as an ergogenic aide in a wide range of sports for its increase in vitality. A nation's pasttime became the outlaw in professional sports. In later years, the stimulating drug was placed on a monitoring list to deter abuse. An exploration into the history, chemical properties, and mechanisms of blocking adenosine receptors to achieve stimulating effects gives us a better understanding of how the drug works. Some physiological responses are not as clearly understood as others, but are determined to be beneficial to habituated users. As the energy drink selection has grown, so has the addiction. Many are unaware of the amount of caffeine they are consuming which could easily desensitize them. Sex, age, and activity level are all factors that should be considered when trying to determine whether caffeine has the benefits it has been demonstrated to possess. Potential abuse of the psychoactive drug in professional sports is a major concern and is continually monitored by the World Anti-Doping Agency (WADA).