Investigating the Role of Hif-1 in Resisting Infection by Staphylococcus aureus in Caenorhabditis elegans
The hypoxia inducible factor (HIF-1) is a transcription factor that during hypoxia sets in motion a genetic cascade that decreases metabolism and ultimately results in increased longevity in the wild type Caenorhabditis elegans. (Lee et al., 2010). HIF-1’s affect on longevity in Caenorhabditis elegans may also affect the nematode’s ability to resist bacterial infection. To test the resistance to infection by Staphylococcus aureus, wild type Caenorhabditis elegans were examined and compared to resistance in the Hif-1 knockout and Ia-7 over-expressor. The Hif-1 mutant strain is not capable of producing HIF-1and therefore does not have the ability to activate the longevity response in low oxygen environments. The Ia-7 mutant over-expresses the HIF-1 by preventing protein degradation.
Measurement of Adenine Nucleotides in Caenorhabditis elegans With and Without Staphylococcus aureus Infection
Organisms use Adenosine Triphosphate, or ATP, as a source of energy from catabolic reactions in order to perform daily activities. ATP levels can be representative of the metabolic response as a whole. This information may be useful when studying the effects of infection. Evidence suggests that infected organisms have marked alterations in metabolic activity. By examining ATP levels in Caenorhabditis elegans nematodes in both non-infected and Staphylococcus aureus-infected nematodes, metabolic responses can be assumed. If the metabolic response of an infected organism differs from a non-infected organism, it can be presumed that metabolism has been altered during infection. We hypothesize that infected nematodes will have a higher reading of adenosine nucleotides, because metabolic levels will be spiked to fight the infection. If true, with this information, future replacement therapies can be developed targeting different metabolic pathways, ultimately resulting in a better outcome from infection or even immunity from a pathogen.
Belmont University
219 • Justin Hughes, Nick Ragsdale
Potentially Protective Effect of Caffeine in Caenorhabditis elegans Treated With 6-Hydroxydopamine
Dopamine nerve loss is understood to be the primary cause of Parkinson’s disease, and the current treatments for Parkinson’s disease have many negative side effects. The model organism Caenorhabditis elegans has long been a model organism to study the disease. When looking at Parkinson’s disease in other mammals such as rats, caffeine has been shown to have a neuroprotective effect on the loss of the dopaminergic nerves. Further, caffeine has been shown to be an antagonist to the adenosine receptor A2A, which is believed to play a key role in the degradation of dopamine nerves. Lastly the following research examined the neuroprotective effects of caffeine on C. elegans treated with neurodegenerative chemical 6-OHDA. The results of the research may lead to a better treatment and possible prevention to the onset of Parkinson’s disease.
Belmont University
220 • Simone M. Dixon, Victoria L. Turgeon
Relative Gene Expression of Protease-Activated Receptor-1 (PAR-1) Mrna in Rat Schwann Cells Following Receptor Activation
Protease Activated Receptor-1 (PAR-1) is a G-protein coupled receptor activated by the serine protease thrombin. In the nervous system, activation of PAR-1 induces apoptosis of avian spinal motor neurons during the period of programmed cell death and reduces outgrowth of neurites. The PAR-1 receptor is also localized on oligodendrocytes and Schwann cells near the node of Ranvier. We localized the PAR-1 receptor to the surface of rat Schwann cells using immunocytochemistry and confirmed gene expression with qRT-PCR (quantitative real-time reverse transcription PCR) studies. To determine if PAR-1 receptor mRNA is regulated by a feedback mechanism after initial activation, Schwann cells were treated with 100 nM of the synthetic peptide SFLLRNP to activate PAR-1, and qRT-PCR was conducted at 0, 4, 8, and 12 hours following PAR-1 activation. There was no up- or down- regulation of PAR-1 receptor mRNA after activation at any of the time points, indicating constitutive expression of PAR-1 mRNA. However, these results do not address the specific localization of the receptor to the surface of the plasma membrane. Given that surface expression of PAR-1 is regulated by feedback mechanisms in other cell types, future investigation of PAR-1 localization is warranted. If PAR-1 surface expression is changed following activation, responsiveness of cells to thrombin may be altered, disrupting the normal balance of PAR-1 signaling in the nervous system and contributing to disease states.
Dept of Biology, Furman University, Greenville, SC
Role of Beta Oxidation in the Immunological Response to Staphylococcus aureus in Caenorhabditis elegans
The rate of obesity in the United States is extremely high and continues to grow. Many studies have been conducted linking obesity to certain diseases, however less is known about obesity’s effect on the immune system. The Caenorhabditis elegans worm will be used in this study to explore the effects of obesity on immune function. The vast amount of identified immune and metabolism pathways of the C. elegans make it an excellent candidate for this exploration of the effect of obesity on immune function. Mutations in the tub-1 gene in the C. elegans have been determined to increase fat deposition and mimic what is seen in obese humans. Both Tub-1 mutant C. elegans worms and wild types will be exposed to the bacterium, Staphylococcus aureus which is known to decrease lifespan. The death rates of these groups will be compared to the death rates of bothTub-1 mutant and wild type C. elegans worms not exposed to the bacterium.
Belmont University
222 • John Taggart
Distribution and Management of Invasive Plant Populations in State Park Properties of the North Carolina Coastal Plain
The North Carolina Division of Parks and Recreation manages 32,063 ha of coastal plain lands divided among 26 properties comprised of state parks, state natural areas, and a state recreation area. Of 35 invasive plant species found at 25 reporting sites, Japanese honeysuckle (Lonicera japonica Thunberg) and privets (Ligustrum spp. L.) occurred most frequently followed by: sericea (Lespedeza cuneata [Dumont-Cours.] G. Don), Japanese stiltgrass (Microstegium vimineum [Trinius] A. Camus), alligatorweed (Alternanthera philoxeroides [Martius] Grisebach), Bermuda grass (Cynodon dactylon [L.] Persoon), common reed (Phragmites australis [Cavanilles] Trinius ex Steudel ssp. australis), silverberries (Elaeagnus spp. L.), mimosa (Albizia julibrissin Durazzini), and wisterias (Wisteria spp. Nuttall). Current management measures for these species and others include herbicide applications, hand pulling to intensively-focused labor with equipment, or use of biological controls. These activities challenge missions, budgets, and staff time of each park unit such that early detection and rapid response are difficult. A dedicated staff position, invasive plant management team, and development of simple control guidelines for vines and herbs are recommended to enhance on-site efforts and provide consistency, while contractual assistance and collaborative efforts will be needed to control difficult or wide-spread populations. Regular monitoring and proactive management at sites with few to no invasive species should be given priority to avoid future problems. In addition to current challenges posed by invasive plant populations found at most sites, species introductions and spread as a function of climate change, sea level rise, and tropical storms are likely.
A comparison of seed longevity of eastern United States tree species for seeds of varying ages
There are now major efforts underway to preserve plant seeds for long periods of time. Though these efforts are expensive and involve technology not readily available to the average person, seed storage should be made more accessible for preservation purposes. This study focused on the longevity of seven tree/shrub species native to the southeastern US: yellow-poplar (Liriodendron tulipifera), sugar maple (Acer saccharum), red maple (Acer rubrum), eastern white pine (Pinus strobus), rosebay rhododendron (Rhododendron maximum), eastern hemlock (Tsuga canadensis) and red spruce (Picea rubens). Fifteen-year-old seeds stored in a household refrigerator at approximately 3˚C since being purchased in 1997 were stratified. New seeds of each of these species were also stratified. After stratification we planted the seeds in the Elon University greenhouse and monitored germination for 2 months. Our results indicate that both sugar maple (80% old seed, 83% new) and yellow-poplar (4% old and 5% new) germinated, suggesting seeds of these species can remain viable for at least 15 years. Results of the other species were equivocal: no older seeds germinated but some younger seeds did. A tetrazolium chloride test indicated survivorship (6.7-60% viability) for all species. We feel that the low germination is attributable to damping-off in the greenhouse after planting. Fungal growth was a problem on seeds during stratification and could have contributed to the poor germination results. The results suggest that individuals can preserve seeds of at least some eastern forest woody species.
Department of Biology, Elon University, Elon, NC P1 • Riley Z. Tunnell1, David A. Johnson2
