|
Article Excerpt
BOTANY SECTION
JEFF LEBKUECHER, CHAIR
MANAGING TABLE MOUNTAIN PINE (PINUS PUNGENS) FORESTS WITH PRESCRIBED FIRE. Nicole Turrill Welch, Middle Tennessee State University, Murfreesboro, Tennessee. Table Mountain pine (Pinus pungens Lamb.) is a fire-dependent species endemic to the southern Appalachian Mountains. Cones of P. pungens are serotinous and stand regeneration requires medium to high-intensity fires that release seed, expose mineral soil, and open the forest canopy. Historically, P. pungens forests have been maintained by lightning- and human-caused fires. Following more than 65 years of fire suppression, most stands have increased densities of chestnut oak (Quercus prinus L.) and scarlet oak (Q. coccinea Muench.) as well as fire-intolerant species such as red maple (Acer rubrum L.). Regeneration of P. pungens is more successful by wildfire than by prescribed fire, as current prescribed burning guidelines limit our ability to achieve medium to high-intensity burns. Furthermore, something seems to be inhibiting P. pungens regeneration in some stands, even following medium- or high-intensity prescribed fires. Future studies will assess the effects of soil chemistry on P. pungens seed germination and oak competition on seedling survival.
NOTES ON THE DISTRIBUTION OF RARE PLANT SPECIES ON CEDARS OF LEBANON STATE FOREST, WILSON COUNTY, TENNESSEE. Claude J. Bailey Jr., Tennessee Department of Environment and Conservation, Division of Natural Heritage, Nashville, Tennessee. Cedars of Lebanon State Forest is a 7,986-acre state forest and natural area located within the central basin of southwestern Wilson County, Tennessee. A biological assessment of the various habitats within the forest was conducted by the Division of Natural Heritage to aid Tennessee Division of Forestry in its land management responsibilities. The focus of this presentation is to report the distributions and occurrences of rare plant species both relocated and discovered in our work. The Division of Natural Heritage currently tracks 192 occurrences of 16 rare plant species within Cedars of Lebanon State Forest. Thirteen of these 16 are indicative of the limestone cedar glade habitats found in abundance within the forest boundaries. The abundance of rare cedar glade flora such as Astragalus tennesseensis, Phlox bifida ssp. stellaria, and Talinum calcaricum emphasizes the value of the Cedars of Lebanon State Forest as a globally significant nature preserve.
THE STATUS OF CASTANEA DENTATA AT LAND BETWEEN THE LAKES, STEWART COUNTY, TENNESSEE AND TRIGG COUNTY, KENTUCKY. Joe Schibig and Michael Hill*. Volunteer State Community College and Austin Peay State University, Clarksville, Tennessee. A study of native Castanea dentata specimens was conducted in Land Between the Lakes (Trigg County, Kentucky and Stewart County, Tennessee) from May 2002 to October 2003. For each specimen, GPS coordinates, size, flowering status, presence of blight, elevation, soil series, geological formation, openness of canopy, associated tree species, and other notations were recorded in an Excel spreadsheet. A total of 230 live specimens were located, all on the western edge of Land Between the Lakes. Eight had diameters at breast height (dbh) [greater than or equal to] 10.2 cm; the largest was 28 cm (dbh) and 14 m tall. Twenty-six specimens (11.3%) showed signs of blight. The elevation range for chestnuts was 110-189 m (average elevation, 140 m). All specimens were found on well-drained, gravelly, acidic soils (28.3% on Baxter-Hammock; 23.5% on Bodine Cherty Silt Loam; 18.3% on Brandon-Saffel; 13.9% on Saffel; 8.3% on Brandon Silt Loam; 5.2% on Guin gravelly loam; 1.7% on Nixa Cherty silt loam and 0.9% on Hammack-Baxter). These soils were derived primarily from the cherty Mississippian limestones of the Fort Payne Formation or from Cretaceous gravels. Most (75%) chestnuts were found on very xeric sites (ridges and south to west-facing slopes) and 86 percent of the specimens were in woods with a somewhat open canopy. The species most often associated with C. dentata were Quercus prinus. Q. velutina, Q. coccinea, Acer rubrum, Oxydendrum arboreum, and Vaccinium spp.
FOUR DECADES OF FLORISTIC STUDIES IN LAND BETWEEN THE LAKES, KENTUCKY AND TENNESSEE. Edward W. Chester, Austin Peay State University, Clarksville, Tennessee. Land Between the Lakes (LBL), a National Recreation Area in southwestern Kentucky and northwestern Middle Tennessee, is managed by the United States Department of Agriculture Forest Service (formerly by the Tennessee Valley Authority). The 69,000-ha area is surrounded on three sides by water; the impounded Tennessee River is on the west side, the impounded Cumberland River is on the east, and a canal connecting the two rivers forms the northern boundary. The southern boundary approximates Highway 79. The area is more than 80 percent forested and has been botanically studied for 40 years. This report provides descriptive information as well as floristic analyses that include a numerical summary of the major taxonomic categories, a list of reported but excluded taxa, rare taxa, the woody and introduced components, and floristic affinities. The botanical literature of the area is referenced.
THE VASCULAR FLORA OF FORT DONELSON NATIONAL BATTLEFIELD AND CEMETERY, STEWART COUNTY, TENNESSEE. Edward W. Chester, Austin Peay State University, Clarksville, Tennessee. Fort Donelson National Battlefield and Cemetery is a 250-ha (600-acre) historic site in Stewart County, northwestern Middle Tennessee that preserves the site of a major Civil War battle. The impounded Cumberland River (Lake Barkley) forms the northern boundary. The northwestern boundary is Hickman Creek; other boundaries are without natural demarcations. Indian Creek bisects the Park, generally running south to north. The river, and lower sections of both creeks, are subjected to fluctuating water levels of about five feet between winter (low levels) and summer pools. The topography is mostly dissected uplands with ridges, slopes of various aspects, and ravines. Habitat types range from older hardwood forests, successional fields, limestone outcrops, cultural sites, and mudflats as waters decline in autumn. This paper reports the results of floristic studies from 1982-1985 and from 2000-2002, with occasional visits between. As now known, the vascular flora consists of 718 taxa representing 110 families and 395 genera. Nearly 23 percent (163 species) of the flora is not indigenous. The largest families are the Asteraceae, Fabaceae, and Poaceae. The largest genera are Carex, Eupatorium, Polygonum, and Quercus II (12 each). Six taxa are state-listed; one of these is federal-listed.
FLORISTIC STUDIES WITHIN THE DUCK RIVER UNIT OF THE TENNESSEE NATIONAL WILDLIFE REFUGE, HUMPHREYS COUNTY, TENNESSEE. Stephanie M. Gunn* and Edward W. Chester, Austin Peay State University, Clarksville, Tennessee. The Duck River Unit of the Tennessee National Wildlife Refuge includes 10,817 ha in Humphreys County, Tennessee. It is managed by the United States Fish and Wildlife Service, primarily to provide food, water, and cover for resident, migratory, and over-wintering waterfowl. Most of the unit is bottomlands of the impounded Tennessee and lower Duck Rivers (Kentucky Reservoir) that were agricultural prior to 1945. Management practices include wildlife plantings, agricultural production, and pools where dams and watergates allow water-level manipulations. Wetland habitat and community types include swamps, sloughs, marshes, wet meadows, dewatered zones, permanent deep water, variable shorelines, and bottomland forests. Although limited in area, uplands with secondary forests, successional fields, bluffs and outcrops, home sites, and cemeteries add to habitat diversity. Forty-nine collecting trips in 2001-2003 documented the vascular flora that is known to include 95 families, 408 genera, and 718 species. Over one-half of the species encountered were county records and one [Echinochloa walteri (Pursh) Heller] was a state record. Introduced taxa (121) constitute almost 17 percent of the flora; 145 taxa (20.2 percent) are woody. Large families are the Asteraceae, Cyperaceae, Fabaceae, Fagaceae, Lamiaceae, Poaceae, Rosaceae, and Scrophulariaceae. Large genera are Carex, Cyperus, Desmodium, Eupatorium, Polygonum, Quercus and Solidago. Six taxa are on the Tennessee elements of concern list.
DEVELOPMENT OF A COMPUTERIZED HERBARIUM CATALOGUE FOR THE HENNING MUSEUM, BRYAN COLLEGE. Colin Plank* and Todd C. Wood, Bryan College, Dayton, Tennessee. The herbarium of the Willard Henning Museum contains 2,400 dry-pressed and other specimens collected primarily from the eastern United States. In an attempt to organize the catalogue after a spring, 2000 fire many of the museum exhibits and remaining specimens were catalogued electronically using Microsoft Access. To make these records more accessible, they were moved to MySQL, reducing data redundancy and improving their potential usefulness. Records can now be searched on the Internet by common name, genus, species, and specimen identification number. An advanced search option allows more specific searching of other specimen attributes. The database and all related programs operate on public license software including Linux and Apache, with custom CGI scripts written in Perl. Search results display information and images of specimens as well as integrated search options for GenBank's Taxonomy database, Tree of Life, and the Integrated Taxonomic Information System. The catalogue may be searched at http://www.bryancore.org/museum/.
CHARACTERIZATION OF A NOVEL REPETITIVE ELEMENT BOUNDED BY DIRECT TANDEM REPEATS IN THE RICE (ORYZA SATIVA L.) GENOME. Matthew Croxton* and Todd C. Wood, Bryan College, Dayton, Tennessee. Two drafts of the rice (Oryza sativa) genome provide opportunity for repetitive and transposable element discovery. We compared the genome of rice subspecies japonica to the draft sequence of ssp. indica to detect novel repeat sequences. Our results revealed a 1030-nucleotide repetitive element bounded by short, direct repeats in indica Contig 462. Based on FASTA searches of the japonica and indica genome drafts, we discovered that the repeat is almost 14 times more frequent in japonica (748) than in indica (54). Even when correcting for the unsequenced fraction of indica, the discrepancy is still about 10 fold; implying expansion of the element in japonica since diverging from its common ancestor with indica. BLAST searching of GenBank revealed that the novel repeat shares homology with a 3622-nucleotide LTR of retrotransposon dagul. Although derived from the dagul LTR, the length discrepancy implies that the novel repeat is probably not a solo LTR.
THE EVOLUTION OF TERMINAL INVERTED REPEATS OF RICE (ORYZA SATIVA SSP. INDICA) MINIATURE INVERTED-REPEAT TRANSPOSABLE ELEMENTS (MITES). Leah Lavoie* and Todd C. Wood, Bryan College, Dayton, Tennessee. Miniature Inverted-repeat Transposable Elements (MITEs) are a recently discovered class of transposable elements characterized by small size and short Terminal Inverted Repeats (TIRs). Although the mechanism of MITE transposition is poorly known. the TIRs of MITEs are thought to be important for transposition. If so, the sequences of active MITE TIRs should be highly conserved in the rice genome. We studied MITE TIRs by surveying the rice (Oryza sativa ssp. indica) genome draft using FASTA. Our results revealed discrete size variations in MITEs Crackle and Castaway. In Castaway MITEs, two independent sets of TIRs mark the boundary of the two size classes. In Crackle MITEs, a palindromic sequence that occurs 8-12 times within the MITE accounts for discrete size classes. We discovered one position in the indica genome where an internal segment of Crackle bounded by palindromic sequences had been excised. This evidence confirms the importance of TIRs for MITE transposition.
SEQUENCE ALIGNMENTS REVEAL TWO CLASSES OF TOURIST MINIATURE INVERTED-REPEAT TRANSPOSABLE ELEMENTS ON RICE (ORYZA SATIVA L.) CHROMOSOME 10. Todd C. Wood, Bryan College, Dayton, Tennessee. Because Miniature Inverted-repeat Transposable Elements (MITEs) transpose by an enzyme not encoded by the MITE. MITE size variation occur frequently. I surveyed the complete sequence of rice (Oryza sativa japonica cv. Nipponbare) for the common MITE Tourist using FASTA. Although the Tourist sequence used as a query for FASTA searching was 165 nucleotides long, a size variant of 150 nucleotides was encountered 101 times, constituting 29% of the 348 Tourist elements detected on chromosome 10. Using flanking sequences of one of these truncated Tourist elements as a FASTA query, a novel 350-nucleotide repetitive element was discovered. This novel element completely contains the truncated Tourist element, but the additional sequence does not correspond to any previously identified transposable elements. Multiple sequence alignments of these longer Tourist sequences reveal imperfect 14-nucleotide terminal inverted repeats with a target site duplication of TTA or TAA. I conclude that this longer Tourist-containing element is a MITE.
THE RIPARIAN FLORA OF ROCK CREEK IN THE PICKETT STATE FOREST, TENNESSEE. Bethany Alley and S. K. Ballal. Tennessee Technological University, Cookeville, Tennessee. A floristic analysis was conduced at the Pickett Fate Forest, Tennessee for late spring and summer flora of 2003. Emphasis was placed on the riparian flora of Rock Creek, which flows through the state forest. Riparian areas are the interfaces between terrestrial and aquatic ecosystems. The Pickett State Forest is located on the Cumberland Plateau of Tennessee with an average elevation of 2,000 feet above sea level. The Cumberland Plateau is bound on the west of the Highland Rim and overlooking the Great Valley of East Tennessee to the east. In our analysis, six distinct habitats were observed, including: aquatic, alluvial woods, cobble bars, sandy alluvial woods, ruderal, and riparian periphery. The mouth of Rock Creek begins a half-mile off Backhouse Road, crosses under Highway 154, and eventually enters the Big South Pork National River and Recreational Area. The River finally empties into the Cumberland River in Kentucky. In this investigation, fifty-four species from twenty-five families were documented within a twelve-mile study area. It has been suggested by earlier researchers that many rare species are found in the riparian habitats in Tennessee; in the present investigation only one rare species, Sanicula canadens, was found.
THE PHYSIOLOGICAL SIGNIFICANCE OF NONPHOTOCHEMICAL DISSIPATION OF EXCESS LIGHT ENERGY BY THE PHOTOSYSTEM-II CORE DURING THE DEVELOPMENT OF PHOTOCHEMISTRY. Jefferson G. Lebkuecher, Mandi M. Coleman*, Stephanie M. Gunn*, James O. Harmon*, Rebecca A. Houtman*, Rhonda P. Johnston*, Tanya M. North*, and April S. Warren*, Austin Peay State University, Clarksville, Tennessee. Nonphotochemical dissipation of excess absorbed light energy is essential to prevent prolonged reduction of quinones which will damage photosystem (PS)-II. Dissipation of excess light energy by the PS-II core is not physiologically significant in mature leaves relative to the dissipation of excess light energy as heat associated with xanthophyll pigment conversions. We tested the hypothesis that prior to the development of maximum capacities for dissipation of light energy by photosynthesis and as heat, the magnitude of nonphotochemical dissipation by the PS-II core is sufficient to limit prolonged reduction of quinone[.sub.A]. Etiolated Helianthus annuus L. cotyledons were exposed to 200-[micro]mol photons.[m.sup.-2][s.sup.-1] for 6 h to initiate chloroplast development. One-half of the cotyledons were treated with DCMU to inhibit linear electron transport and xanthophyll-associated dissipation of excess light energy as heat. The concentration of oxidized [Q.sub.A] and the magnitudes of light energy-transduction mechanisms of untreated and DCMU-treated cotyledons were evaluated using modulated chlorophyll a fluorescence. The results demonstrate the potential for dissipation of excess light energy by the PS-II core is sufficient to maintain an optimal fraction of oxidized [Q.sub.A] prior to the development of maximum capacities for photosynthetic electron transport and dissipation of excess light energy as heat.
COMPARATIVE ECOPHYSIOLOGY OF ASTRAGALUS BIBULLATUS AND ASTRAGALUS CRASSICARPUS (FABACEAE). Carol J. Baskauf and Dustine Reppuhn, Austin Peay State University, Clarksville, Tennessee and Alexandria, Virginia. In a comparative greenhouse growth experiment, the endangered cedar glade endemic Astragalus bibullatus grew best under medium to high light and moisture conditions. Very low soil moisture and dense shade strongly inhibited growth. Its widespread prairie congener, A. crassicarpus, grew best with medium light levels and high soil moisture. After two months of growth, A. bibullatus averaged almost twice as many leaves as A. crassicarpus and 2.5 times as much dry biomass. Leaf number and biomass production were uniformly low for both species under conditions of low light and/or low moisture, but the gap between the species widened as light and/or moisture levels increased. Photosynthetic light response curves indicate that A. crassicarpus has higher rates of photosynthesis than A. bibullatus. Maximum rates for both species are in the range typical for heliophytes. Water potential decreased as soil dried, but A. crassicarpus averaged lower water potentials than did A. bibullatus.
THE EFFECTS OF ACID RAIN ON SUNFLOWER PLANT GROWTH. J. L. McElhiney*, S. J. Ramos*, and D. S. Burton, Austin Peay State University, Clarksville, Tennessee. Abstract not available
CELL AND MOLECULAR BIOLOGY
MATT ELROD-ERICKSON, CHAIR
INITIAL PROTOCOL FOR ISOLATING CHICKEN LIVER PHOSPHATASE INVOLVING A PROTOTYPE GRADIENT MAKER. Marcia M. Schilling* and Robin B. Reed, Austin Peay State University, Clarksville, Tennessee. Kinases and phosphatases work to add or remove phosphate groups from molecules in the cell, respectively. In liver cells, phosphatase transfers play vital roles in activating or inhibiting the enzymes of gluconeogenesis and glycolysis that regulate blood sugar in the organism. Isolation of distinct phosphatases from liver tissues might lead to further detailing of these processes. Past protocol revealed that a gradient system was commonly used during column chromatography when isolating phosphatases. A prototype was constructed using lab equipment and tested for its reliability. Chicken liver tissues were then homogenized, applied to a DEAE cellulose column for chromatography, and resulting fractions were tested spectrophotometrically for phosphatase activity using pnitrophenylphosphate as a substrate. One active fraction was concentrated and subjected to SDS-polyacrylamide gel electrophoresis. The resulting gel displayed a prominent band whose molecular weight was around 33,000 Da.
PROTEIN SORTING INTO TRANSPORT VESICLES AT THE ENDOPLASMIC RETICULUM. Matthew J. Elrod-Erickson, Middle Tennessee State University, Murfreesboro, Tennessee. Eukaryotic cells are comprised of a number of organelles that each perform a unique function. To maintain this organization, organellar proteins must be faithfully targeted and transported from the cytosol to their final destination. Secretory proteins pass through a series of organelles during their transport, carried in vesicles that bud from one compartment and fuse to the next. A key question is how the appropriate proteins are sorted into these vesicles so that proteins destined for later compartments are moved forward while residents of an organelle are retained. The bst1 gene of Saccharomyces cerevisiae plays an important role in this process at the endoplasmic reticulum (ER). Mutations in this gene cause a variety of non-lethal sorting defects. A subset of proteins leave the ER more slowly in bst1 mutants, while resident ER proteins are secreted aberrantly. Bst1p may influence the membrane in the vicinity of budding vesicles and thereby affect sorting.
PROTEIN MODELING OF RIBOSE-1,5-BISPHOSPHATE CARBOXYLASE OXYGENASE USING RAZMOL. T. Justin Durham*, S. K. Ballal, and Scott H. Northrup, Tennessee Technological University, Cookeville, Tennessee.
Abstract not available
CLONING AND CHARACTERIZATION OF YEAST LEUKOTRIENE A4 HYDROLASE. Carrie Romer*, Daniel Dorset*, Christopher Meyer*, Michael Thompson, and Rebecca Seipelt, Middle Tennessee State University, Murfreesboro, Tennessee (CR, DD, CM, RS) and Vanderbilt University, Nashville, Tennessee (MT). Human leukotriene A4 hydrolase is a bifunctional enzyme that converts the eicosanoid intermediate leukotriene A4 into leukotriene B4, a molecule that recruits leukocytes to endothelium. It also possesses an aminopeptidase activity, hydrolyzing one amino acid at a time from the amino terminus of its peptide substrates. Budding yeast possess a gene which encodes a protein that is highly similar to leukotriene A4 hydrolase. To characterize the yeast protein and its substrates more fully, we used polymerase chain reaction (PCR) to amplify the gene from yeast genomic DNA and to add an affinity tag for protein purification. The DNA fragment was ligated into a yeast expression vector and colonies were screened by PCR for the presence and orientation of the DNA insert. Four clones with the correct orientation were identified and transformed into yeast. Further studies will involve protein expression and purification, analysis of substrate specificity, and characterization through mutational analysis.
CHEMISTRY
MARTIN V. STEWART, CHAIR
EVALUATING THE INFORMATION CONTENT OF A NEWLY DEVELOPED MOLECULAR DESCRIPTOR. Donald P. Visco Jr., Tennessee Technological University, Cookeville, Tennessee. The recently introduced Signature molecular descriptor is based on an extended valence sequence and belongs...
|
