Development of Sporulating Bacterial Cultures for Incorporation Into Pervious Concrete Before Curing
Observations of pervious concrete in place for more than 10 years often indicate substantial clogging. A pervious study of soil bacteria that might potentially clog this concrete produced three cultures (sporulating, Gram + rods, capsule +) that reduced flow by at most 40%, and in several cases by only 2 to 3%. In this study these cultures were grown in tryptic soy broth (TSB) for five days, and added to pervious concrete mix. Control (sterile saline added) test cores were poured first, followed by the three separate sets of spore-added test cores, all in mid July 2013. After curing, the cores were moved into a storage area in the microbiology lab. They were covered and maintained under ambient conditions (temperature range 19 to 22 oC). The cores were left for approximately six months before control and experimental cores were sampled using an alcohol flamed chisel to cut approximately 2 cm from the outside of the cores at two depths. Then, using flamed forceps, chips from inside the cores were removed and placed in either sterile TSB or onto the surface of TSA plates. These were incubated at room temperature for 72 hours. No growth was observed for any sample from control cores. Growth resembling the culture added to the mix was observed on the TSA plate for samples from an experimental core. Quantification of spore survival in this concrete is ongoing. Potential uses for spore impregnated pervious concrete could include the bioremediation of hydrocarbon wastes typically found on concrete surfaces.
Dept of Biological and Environmental Sciences, University of Tennessee at Chattanooga, Chattanooga, Tennessee
167 • Crystal N. LeBlanc, Jennifer T. Thomas
The Evaluation of Type I Interferon Levels in HPV-Positive Cervical Cancer Cell Lines
Human Papillomavirus (HPV) is the most common sexually transmitted virus in the United States and the leading cause of anogenital and oropharyngeal cancers. Previously, it has been determined that levels of IRF-3, a transcription factor allowing for expression of antiviral type I interferons, are reduced in HPV-positive cervical cancer cell lines. As an extension of this work, we wanted to determine if type I interferon levels themselves are also reduced in the presence of HPV by Western Blot analysis. We confirmed decreased levels of IRF-3 in HeLa cells versus C33A cells. Original analysis of cell lysates revealed faint expression of Interferon-a and Interferon-b for both cell lines, however, the levels were too low to distinguish between the samples. Given that Interferon-a and Interferon-b are secreted proteins and their levels of expression in cell lysates were low, we next examined supernatants for Type I interferons. Analysis of supernatants indicate possible dimer formation of the Type I interferons in C33A and HeLa cells. Future studies can compare levels of the secreted interferons between C33A and HeLa cells. Taken together, these results may indicate that HPV can suppress antiviral activity downstream of IRF-3 and potentially contribute to immune evasion and cancer progression.
168 • Grace L. Chafin1, James W. Brown2, Melanie J. Lee-Brown1
Mutagenesis of the FMN Riboswitch of Photorhabdus Luminescens and an Analysis of Mutagenic Effects on Its Pathogenicity on Caenorhabditis Elegans
Riboswitches are an important aspect of the regulation of some genes in bacteria. The binding of effector molecules to mRNA leader regions specifies their secondary structures, which modulates transcription termination and therefore the expression of downstream genes. This study examines the FMN riboswitch located upstream of the rib operon in Photorahbdus luminescens, and seeks to determine if this region of regulatory RNA is a potential target for novel antimicrobials. The pathogenicity of this bacterium on its host, Caenorhabditis elegans, will be examined via mutagenesis to lock the riboswitch in the on or off conformations using the lambda-Red recombineering system. If the bacterium loses virulence when the FMN riboswitch is locked in the off confirmation, it may mean that the bacteria cannot bypass the rib pathway and can therefore not sequester FMN from its host. This finding would focus attention on the FMN riboswitch as a potential target for novel antimicrobials for use against multi-drug resistant bacteria.
1 Biology Dept, Guilford College, Greensboro, NC; 2Dept of Biological Sciences, North Carolina State University, Raleigh, NC
169 • Jake H. Billmyer, Frank S. Gilliam
Effects of Nitrogen Deposition on Rubus Spp. (Raspberry) Within a Central Appalachian Hardwood Forest
The impact of anthropogenic increases in nitrogen (N) deposition on aquatic and terrestrial ecosystems is topic of on-going ecological concern, with such increases arising primarily from combustion of fossil fuels and use of N-based fertilizers. Rates of N deposition that exceed biotic demand can lead to N saturation, potentially decreasing plant biodiversity. Excess N can also enhance leaching of mobile NO3- from terrestrial ecosystems, accompanied by loss of nutrient cations, such as Ca++, Mg++, and K+. Since 1989, N has been applied aerially to a single watershed (WS3) at the Fernow Experimental Forest (FEF), Tucker County, West Virginia. Preliminary results show Rubus spp. (hereafter, Rubus) shifting from a minor to dominant constituent of the herbaceous layer in response to N treatment. This study is part of long-term research at FEF that examines effects of excess N deposition on a hardwood forest ecosystem. The purpose of the study is to 1) quantify Rubus response to N treatment, 2) relate Rubus cover to herb layer species richness, and 3) test the hypothesis that increased Rubus cover will result in decreased biodiversity. Results show significant decrease in species richness along with a significant increase in relative Rubus cover from 1994--2013. Because Rubus is considered shade intolerant, these represent novel finding of increased Rubus cover under the closed WS3 canopy and demonstrate counter-intuitive impacts of increasing anthropogenic N on the herbaceous layer of hardwood forest ecosystems.
