Bacterial Forensics: Revolutionizing Biochemical Analysis

Eva Childrey is a junior forensic science and chemistry double major working in Dr. Eh- rhardt’s research laboratory at VCU. The main goal of the research conducted in this laboratory is to explore the lipid profiles of different bacterial species

Investigations into Aldefluor as a Novel Method for Identifying Leukemia in Soft-Shell Clams

The clam species Mya arenaria is a common model organism in leukemia research. The current method for classifying the degree of cancer progression is by examining cell morphology with light microscopy. This approach is highly qualitative, which makes differentiation of pre-leukemic and semi-leukemic individuals difficult. One quantitative approach that may differentiate individuals is based on levels of aldehyde dehydrogenase (ALDH) expression. The enzyme assay ALDEFLUOR® can actively measure ALDH expression in viable cells, but the effectiveness of certain protocol conditions is dependent upon the cell type

Salt Marsh Values in a Changing World: Examining Sea Level Rise on Tidal Marshes with a Surface Elevation Table

Rising seas are threatening coastal communities and putting added pressures on the natural environment. Sea level rise rates are increasing on a global scale (from 1.7 to 3.2 mm/yr). Salt marshes are not only intertidal habitats acutely influenced by sea levels, but they also provide key ecosystem services such as: buffers against storm surges, habitat for wildlife, carbon dioxide storage, and pollutant filtration. In New England, salt marshes have built at a rate of 1 to 2 mm annually over the past 4,000 years, which has kept pace with sea level rise. However, we do not know if salt marshes can keep building if sea levels rise at a more rapid rate of 4 mm/yr or greater. To monitor how salt marshes are responding to faster sea level rise, we measured salt marsh accretion and elevation change along the coast of New Hampshire at three different marshes (a total of 11 stations) using marker horizons and a Surface Elevation Table (SET). The SET sites were established in two marshes over a decade ago and more recently at a third marsh in 2011. Data were collected in 2013 and the new rates are compared to previous elevation changes. The major findings included an unprecedented marsh elevation growth rate of 4.3 mm/yr, which shows that our marshes are building at rates fast enough to keep up with the current sea level rise. Furthermore, the rate of salt marsh building appears to be greater than the global sea level rate of 3.2 mm/yr, suggesting our local rate of sea level rise may be greater than 3.2mm/year. Salt marshes could provide a valuable indirect measure of local sea level rise

From Observers to Participants: Joining the Scientific Community

In this essay, we have integrated the voices of our mentors and students to explore 45 years of undergraduate research experiences and their role in shaping our scientific community. In considering our collective experiences, we see undergraduate involvement in research as a rich source of community development, one that has both touched our lives and influenced our teaching

Filtering efficiency and feeding mechanisms of Daphnia pulex on Microcystis aeruginosa and Nannochloropsis

The filtering and feeding rate of Daphnia pulex from the Old Durham Reservoir, Durham, NH, were measured to determine the feeding efficiency on different concentrations of non-toxic Nannochloropsis (Class Eustigmatophyceae) and toxigenic cyanobacteria Microcystis aeruginosa. Direct observations of thoracic appendage beats and post-abdominal rejections were also measured at 5*105 and 106 cells mL-1 concentrations of Nannochloropsis and M. aeruginosa to examine the feeding mechanisms of the D. pulex. In the presence of increasing Nannochloropsis concentrations, the filtering rates decreased and the feeding rates increased. When exposed to M. aeruginosa, both the filtering and feeding rates decreased. The thoracic beats decreased and the post-abdominal rejections increased from 5*105 and 106 cells mL-1 of both food types. Similarly, the thoracic beats decreased and post-abdominal rejections increased from food suspensions of Nannochloropsis to M. aeruginosa. These results indicate that when compared to Nannochloropsis, M. aeruginosa had a negative effect on the feeding rates over a wide range of food concentrations of the Daphnia. The lowered feeding rates are in part due to a reduction in collection rates (i.e. lower thoracic appendage beats) and an increase in the food rejection as evidenced by the higher post abdominal rejection rate

A Preliminary Investigation of Acculturative Stress and Diurnal Cortisol Among Latina Women

The interplay between biological and cultural factors has remained understudied among ethnic minority groups, including Latinos. To the best of our knowledge, minimal to no research has examined the relationship between acculturative stressors and diurnal cortisol among Latina women. This initial exploratory study sought to examine the relationship between cortisol and acculturative stress. Among a small sample of adult Latina women, salivary cortisol was collected at 3 time points (waking, 30 min postwaking, and bedtime) to assess the cortisol awakening response (CAR) and diurnal cortisol response. Information regarding acculturative stress and acculturation was also collected. The major results showed that high levels of acculturative stress were associated with a blunted CAR and a flatter diurnal cortisol response when compared to low levels of acculturative stress. These preliminary findings highlight the potential role of cultural stressors in contributing to the biological stress response

PO2 dependence of oxygen consumption in skeletal muscle of hypertensive and normotensive rats

Human essential hypertension affects over 75 million people in the United States, and can lead to death due to its several serious health complications such as hypertension-related cardiovascular disease. The purpose of this research was to understand how hypertension could cause physiological changes to the microcirculation, specifically the PO2 dependence of oxygen consumption (VO2) in skeletal muscle of normotensive and hypertensive rats. The Spontaneously Hypertensive Rat (SHR) strain was used as the diseased model, and Wistar-Kyoto (WKY) rats were used as controls to conduct this study. The SHR strain develops hypertension between 5-6 weeks after birth with an average systolic blood pressure of 150 mmHg. By arresting blood flow using an objective-mounted inflatable airbag, PO2 measurements were obtained along with an oxygen disappearance curve (ODC), which was used to calculate VO2 over various ranges of physiological PO2 values. PO2 and VO2 curves were analyzed based on Hill’s equation to fit the data and describe the PO2 dependence of VO2. When compared to the healthy Wistar-Kyoto rats, the SHRs exhibited a higher Vmax, or maximum rate of oxygen consumption. The average maximal rate of consumption by the hypertensive animal models could be a consequence of a “mitochondrial uncoupling” or some disconnect in the mitochondrial oxygen consumption and the normal corresponding ATP production. In conclusion, this project demonstrated that in situ muscle tissue from hypertensive and normotensive rats had a PO2 dependence of oxygen consumption over a wide range of physiological PO2 values and the hypertensive rats consumed oxygen at a higher maximal rate