Section I: Biological sciences.
** Denotes student "in progress" research
8:15 THE CONSTITUTIVE NATURE OF LYSOZYME IN HOUSEFLIES **, Christopher Evett *, Dana Nayduch and Ashika Patel *, Georgia Southern University, Statesboro, GA 30460. Because they live and breed in extremely septic environments and are often associated with humans, houseflies (Musca domestica) are important vectors of many diseases. To get an idea of the immune system component of the interaction between bacteria and houseflies, housefly lysozyme expression was examined by RT-PCR throughout the life-cycle of the organism from undeveloped egg in utero to old-age adult. Bacteria-fed adult flies will be examined for a change in lysozyme expression, and fly mortality will be measured after a combination of bacteria and lysozyme-inhibitor are introduced. By expression analysis and chemical inhibition of lysozyme, the aim of this study is to prove the central role that lysozyme plays in housefly immunity.
8:30 A PRELIMINARY ASSESSMENT OF THE PRIMARY LARVAL MORPHOLOGY OF MATUS OVATUS LEECH (DYTISCIDAE: COLEOPTERA), Brandi Dent * (1), J.W. Amnions * (1), E.H. Barman (1), T.A. Shepley-James (2) and B.P. White (2), (1) Georgia College & State University, Milledgeville, GA 31061 and (2) Georgia Military College, Warner Robins, GA 31093. The Matinae van den Branden, hypothesized as the sister-group to the remaining Dytiscidae, has relatively few species that are restricted to Nearctic and Australian regions. The genus Matus Aube is represented in Georgia by two species, M. bicarinatus (Say) and M. ovatus Leech, easily distinguished from other dytiscid larvae by the presence of pseudochelate modifications of tibiae and tarsi. Primary larval (first instar) morphology has been shown to be important in dytiscid systematics. However, although descriptive information for mature larvae of M. ovatus is available, the morphology of first instars of M. ovatus is unknown. The analysis of the primary chaetotaxy of legs, head, and last abdominal segment of M. ovatus revealed no significant differences between this species and M. bicarinatus. Undescribed matine primary anatomical features presented herein include: i) anterior tentorial pits and fragments of the anterior tentorial arms; ii) pronotal anterior modifications and chaetotaxy; and iii) complete sclerotization of the seventh abdominal segment. Differences in mandibular morphology permit identification of first instars of Georgia species of Matus. This project was supported in part by a Faculty Research Grant, Office of Research Services, Georgia College & State University. Aquatic Coleoptera Laboratory Contribution No.79.
8:45 THE EFFECTS OF PRESCRIBED BURNING AND POPULATION FRAGMENTATION ON THE DEMOGRAPHY OF THE FEDERALLY ENDANGERED HERB. TRILLIUM PERSISTENS, AND ITS COMMUNITY **, Cassandra M. Plank * and Lissa M. Leege, Georgia Southern University, Statesboro, GA 30458. Trillium persistens is a federally endangered perennial herb that is restricted to three counties in Georgia and one in South Carolina where it exists in fragmented populations. At Tallulah Gorge State Park, T. persistens co-occurs with the threatened Table Mountain pine ecosystem, which requires fire. The effects of fire are unknown for T. persistens. The objectives of this study were to analyze the effect of fire on demography of T. persistens, compare population structure among sites to evaluate demography across the range of T. persistens, and to analyze community composition and structure. Four study sites were established in spring 2009. A prescribed burn was conducted in one site in February 2009 to test the effect of fire on T. persistens populations. A census of T. persistens populations was conducted in spring and summer of 2009 for each site; each plant was marked with a numbered metal tag and life stages recorded. Stage structure differed among sites ([X.sup.2] = 35.337, P = 0.0001) with subadults representing the largest group (55.09%) while seedlings represented the smallest (2.3%). Stage structure did not differ between the burned and unburned sites at Tallulah Gorge following the burn ([X.sup.2] = 3.238, NS). Results are pending for community composition and structure analyses. The Department of Natural Resources and Georgia Power provided assistance for this research.
9:15 A PHYLOGENETIC COMPARISON OF UNICELLULAR SUBAERIAL GREEN ALGAE FROM SOUTH GEORGIA **, J. D. Griner * and J. A. Nienow, Valdosta State University, Valdosta GA 31698. Subaerial algae are a diverse group of photosynthetic microorganisms defined by their ability to grow on surfaces exposed directly to air. While some groups of subaerial algae, most notably the Trentepohliales, form complex structures, most are morphologically simple, making assessments of genetic diversity and phylogenetic relationships difficult. In this study, we examine the genetic diversity of 20 strains of unicellular green algae isolated from subaerial sites in southern Georgia. All of the strains are morphologically similar. To differentiate the isolates, we will use universal eukaryotic 18s ribosomal primers (SSU1 and SSU2) in PCR assays. Genomic DNA will be extracted via a modified CTAB method. The small subunit 18s region will be amplified by PCR using SSU primers and PCR products will be subjected to gel electrophoresis. Properly amplified and purified PCR products will be sequenced. Sequence comparison and phylogenetic tree construction will be performed using Geneious software. These sequences will be compared to previously published green algal sequences to better understand the phylogenetic relationships of green algae and to assist in the identification of potentially cryptic species.
9:30 CYANOBACTERIA ASSOCIATED WITH MICROBIALITES FROM PAVILION LAKE, CANADA **, J. Trull * and J. A. Nienow, Valdosta State University, Valdosta, GA 31698. Microbialites are rock formations that develop at least partially through the activity of photosynthetic microorganisms. Well-known examples include formations in Shark's Bay, Australia, and Exuma Cay, Bahamas. The work reported here is part of a long-term study of microbialite formations in Pavilion Lake, British Columbia. Pavilion Lake is a circumneutral (pH 8.4), highly oligotrophic freshwater lake with a maximum recorded depth of 65m. Microbialites of varying morphologies develop all along the walls of the lake. Our role in the project is to inventory the photosynthetic microorganisms associated with the microbialites and to assess potential relationships between photosynthetic associations and the morphology of the microbialites. Cyanobacteria, in particular, are thought to play an important role in microbialite formation. Samples of living microbialites were collected in September, 2009, and shipped to Valdosta State University. Aliquots of each sample were preserved in glutaraldehyde for investigation later. Live material is being examined using light microscopy after decalcification with 5%o EDTA. In addition, attempts are being made to develop unialgal cultures using the algal media BG11, BBM, and a version of BBM modified to maintain pH near 8. Our preliminary investigations indicate that members of at least nine genera of cyanobacteria are present, several of which are thought to precipitate calcium carbonate in other aquatic systems.
9:45 CHARACTERIZATION OF WATER QUALITY PARAMETERS ALONG A NORTH TO SOUTH TRANSECT IN FRENCHMAN BAY, ME **, Demi Brett Rabeneck * and James B. Claiborne, Georgia Southern University, Statesboro, GA 30458. Interest in maintaining marine biodiversity creates awareness of ocean acidity and its impact on fish physiology. We characterized the pH and associated water quality parameters, including temperature, salinity, dissolved inorganic carbon (DIC), and total alkalinity (TA), of a small transect in Frenchman's Bay, ME. Twenty-one water samples from depth and surface were collected on three separate days by lowering a niskin bottle on a line at three coordinates along a South to North transect. The coordinates stretched from the Mount Dessert Island Biological Laboratory (N44[degrees]26'02.3", W068[degrees]17'25.5"), through open pelagic waters (N44[degrees]26'21.8", W068[degrees]17'21.8") to Lamoine Beach (N44[degrees]27'00.4", W068[degrees]17'10.2"). The Ocean Process Analysis Lab of the University of New Hampshire in Durham measured the DIC, TA, and pH, with salinity and temperature measurements provided in replicates of three or four. A Mann-Whitney-U test showed a significant difference between pH at depth and at surface (U=1109, df =1, P < 0.0001), with a mean pH of 7.75 [+ or -] 0.08 and 7.91 [+ or -] 0.41, respectively. This difference in pH coincided with a significant difference in TA at depth (2086 [+ or -] 32.5 [micro]mol/kg) and at surface (2035 [+ or -] 79.3 [micro]mol/kg) (U=1035, df = 1, P < 0.0001), Larger amounts of TA give the ocean a greater buffering capacity for [H.sup.+] ions, a product of CO2 absorption. In future experiments pH values may be used to see if sodium hydrogen exchangers (NHEs) of Marine Longhorn Sculpin, Myoxocephalus octodecemspinosus, acclimate to maintain homeostasis. Our results are based on a subset of the final data, but should support the prediction that sculpin NHEs acclimate to increased acidity levels since this demersal species has to cope with lower pH than species living in shallower waters.
10:00 Section business meeting
MOVEMENTS OF SOUTHERN FLYING SQUIRRELS (GLAUCOMYS VOLANS) IN A FRAGMENTED FOREST **, Jamie Adams *, Lindsay Brotherton *, Paul Smith * and Thomas Nelson, North Georgia College and State University, Dahlonega, GA 30533. Southern flying squirrels are found in forested habitats throughout the eastern U.S., inhabiting deciduous and mixed forests in the Appalachian region. Because the species moves primarily by leaping and gliding among trees, forest fragmentation may impact movements, home range, and dispersal. Yet few studies have addressed the spatial ecology of this species. We initiated a long-term study to investigate: (1) home range size, (2) habitat use, and (3) impacts of road development on the movements of squirrels in a hardwood forest on the NGCSU campus. Squirrels were live-trapped, radio-collared, and tracked regularly from May-September 2009. We live-trapped a total of 13 squirrels, including 7 males and 6 females. The mean fixed kernel home range size for all squirrels was 8.3 ha (4.4 SE), whereas the core areas averaged 2.1 ha (1.2 SE). These home ranges are generally comparable to those reported by other researchers in the SE U.S, an indication that our study area provides high quality habitat. Of 16 den trees, 81% were either white oaks or poplars. Den trees tended to be living trees (not snags) with large diameters (mean = 136 cm; SD = 37.3). Midway through the study, the university built a 30-m wide road bisecting the study area. During road-building, squirrels shifted their home ranges away from the disturbance. Subsequently, the road proved to be no barrier to movements as individuals were sometimes located on both sides in a single activity period. Research is continuing to better quantify seasonal movements and microhabitat use.
INFLUENCE OF WATERSHED LAND-USE ON STREAM FISH COMMUNITIES IN NORTH GEORGIA **, Michael Damron *, Kyle Stowe *, Wade Holcomb *, Lindsay Brotherton * and Thomas Nelson, North Georgia College and State University, Dahlonega, GA 30533. Aquatic biodiversity is high in the streams of north Georgia, but this region is experiencing unprecedented exurban growth and urban development. To investigate the relationship between local land use and fish communities in headwater streams, we analyzed the relationship between sub-watershed land use and two measures of stream quality, the Index of Biotic Integrity (IBI) and the Index of Well-Being (IWB) at 10 sites along 5 first- and second-order streams in the Chestatee River watershed. Sites were classified as urban, agricultural, or forested based on the predominant land-use in each sub-watershed. We hypothesized that both indices would decline from forested to urban sites. A total of 906 fishes of 25 species was processed during the study. Based on a composite of both indices, forested sites were usually good to excellent, agricultural sites were highly variable, and urban sites were fair to poor. Although sample sizes were small, our data suggest that increased intensity of local land use alters the composition of stream fish communities, lowering biotic integrity.
SURVIVABILITY OF GFP-EXPRESSING ESCHERICHIA COLI IN THE DIGESTIVE TRACT OF HOUSE FLIES (MUSCA DOMESTICA) **, Naveen Kumar H.V * and Dr. Dana Nayduch, Georgia Southern University, Statesboro, GA 30460. House flies are cosmopolitan and have indiscriminate feeding habits, and are involved in the propagation of many bacterial diseases that affect humans. Ingested bacteria are first harbored in the fly's crop, from which they are either regurgitated or diverted into the midgut for digestion. Although house flies have been shown to lyse bacteria within their alimentary canal, some species of bacteria persist within the fly for various periods of time. Since surviving bacteria may be disseminated and/or excreted from infected flies, persistence directly affects the potential of the fly to be a vector or reservoir for these organisms. This study investigated the location, survival and persistence of bacteria in house flies. Adult house flies were fed a known amount of GFP-expressing Escherichia coli, and both quantitative (bacterial enumeration by culture-recovery) and qualitative (flourescent microscopy of dissected fly digestive tracts) assessments were performed. Preliminary results demonstrated that E. coli persisted in whole-fly homogenates for up to 48 hours post-ingestion (hpi). Viable E. coli cells, as determined by cellular integrity along with GFP expression, were viewed using microscopy, and their location in the alimentary canal was determined. These observations were compared to bacterial enumeration tests at different times post ingestion, to determine the actual location of surviving bacteria within the flies. Initially, bacteria were present in the crop, but then many entered the alimentary canal where they were progressively lysed, as soon as 6 hpi. The role of house flies as significant reservoirs or vectors of E. coli will be discussed.
REPRODUCTIVE BIOLOGY OF THE ENDANGERED HERB TRILLIUM PERSISTENS IN NATURAL CONDITIONS, Chase H. Patrick * and Dr. Lissa M. Leege, Georgia Southern University, Statesboro, GA 30460. Fragmentation can adversely affect species, potentially pushing them towards collapse. Trillium persistens is an endangered herb that occupies a narrow range in NE Georgia and SW South Carolina, recently fragmented by a dam. This experiment examined the reproductive biology of T. persistens in two sites in Georgia. In Spring 2009, we studied the pollination biology of T. persistens by administering three treatments: open and supplemental pollination and simulated florivory We harvested ripe fruit in July 2009. Persistence of plants through fruit harvest did not differ by treatment, and because persistence indicates successful fruit set, we infer that fruit production did not differ by treatment. Eighty-six percent of the marked plants persisted until the time of fruit harvest, and therefore likely produced fruit though fruits were not present on all plants. Fruits contained 4.97 [+ or -] 0.33 seeds, though treatment did not affect seed production. Fruit diameter and seed number were strongly correlated ([R.sup.2] =0.5864, P =0.0001). We conclude that the small population size of T. persistens is not limited by pollinators, suggesting resource limitation. The correlation between fruit diameter and seed number can also be used to better estimate seed production non-destructively. Further research is needed to better understand resource limitation in T. persistens to improve conservation practices. We would like to thank the Chandler Research Fellowship, the Department of Natural Resources and Georgia Power for supporting for this research.
DIATOM ASSEMBLAGES ASSOCIATED WITH MICROBIALITES FROM PAVILION LAKE, CANADA **, A. J. Williams * and J. A. Nienow, Valdosta State University, Valdosta, GA 31698. Microbialites are rock formations that develop at least partially through the activity of photosynthetic microorganisms. The work reported here is part of a long-term study of microbialite formations found in Pavilion Lake, a circumneutral (pH 8.4), ultra-oligotrophic freshwater lake in south-central British Columbia. Because individual microbialites in the lake have estimated ages between 1,000 and 10,000 years, it is possible that environmental conditions have changed during their period of development. We are investigating this possibility by examining the diatom assemblages both living on the surface and buried within microbialites. The specimens used were collected during the 2004 field season, fixed with formaldehyde, and stored at 4[degrees]C. Samples cut from the surface or cored from the interior of larger specimens were subdivided into 3 parts. One subsample was critical-point dried in the natural state. A second subsample was partially decalcified with 5% EDTA, then critical-point dried. A third sample was treated with concentrated nitric acid to remove all carbonate and organic material. Each subsample was then sputter-coated and observed using scanning electron microscopy. More than 35 diatom taxa have been identified from surface assemblages, including three species of Mastogloia. Fewer taxa were found in the interior. We are continuing to examine the samples to determine if the differences are the result of differential preservation or changes in the environment.
Cunningham Center, Room 310
Shane Webb, Presiding
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|Title Annotation:||SATURDAY PAPER PRESENTATIONS|
|Publication:||Georgia Journal of Science|
|Date:||Mar 22, 2010|
|Previous Article:||Section VII: science education.|
|Next Article:||Section II: Chemistry.|