Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

Electronic Theses and Dissertations

Discipline
Institution
Keyword
Publication Year

Articles 2731 - 2760 of 3160

Full-Text Articles in Life Sciences

Cloning And Sequencing Of Glucosyltransferase (Gt) Genes From Grapefruit (Citrus Paradisi) Seedlings, Searching For 7-O-Gt., Mebrahtu Berhane Sibhatu Aug 2003

Cloning And Sequencing Of Glucosyltransferase (Gt) Genes From Grapefruit (Citrus Paradisi) Seedlings, Searching For 7-O-Gt., Mebrahtu Berhane Sibhatu

Electronic Theses and Dissertations

Flavonoids play crucial roles in plant life cycles and in human welfare. Grapefruit plants produce several glycosylated flavonoids and the glycosylation reactions are catalyzed by UDP-glucose: glucosyltransferases (GTs). Our objective was to use the SMART RACE RT-PCR strategy to obtain cDNA sequences of putative grapefruit flavonoid GTs. Gene specific primers were designed from the plant secondary product glucosyltransferase (PSPG) box and used to amplify 5’GT clones. Clone-specific primers were designed from 5’clones to amplify 3’ GT clones. We obtained 5 5’ clones and 1 3’ clone as candidate GTs. We used 3 of these clones to predict 2 compiled GT …


Host Defense Mechanisms In The Crayfish: The Effect Of Injection With Live Or Killed Bacteria., Kimberly R. Goins May 2003

Host Defense Mechanisms In The Crayfish: The Effect Of Injection With Live Or Killed Bacteria., Kimberly R. Goins

Electronic Theses and Dissertations

An increase in attachment of SRBCs to Procambarus clarkii hemocytes has been shown after the crayfish were injected with a live or killed Pseudomonas strain RS2b. The increase in attachment occurred at 8 hours post injection and peaked at 24 hours for both experimental groups. The population of hemocytes with receptors for LPS and mannose also increased at 8 hours post injection and peaked at 24 hours for both experimental groups. At 96 hours post injection the number of receptor bearing hemocytes and hemocytes bound to SRBCs began to decrease to the level of the control for both groups. The …


Increasing Diabetes Awareness In Adolescents Through Educational Programs., Sandra J. Reese May 2003

Increasing Diabetes Awareness In Adolescents Through Educational Programs., Sandra J. Reese

Electronic Theses and Dissertations

The purpose of this study was to increase knowledge of diabetes and promote healthy lifestyle behaviors to reduce diabetes onset in a community with a relatively high incidence of type 2 diabetes. Three hundred eighty seven students grades 7 – 12 participated in the program and taste test. Changes in knowledge before and after an educational program focusing on diabetes prevention were measured by comparison of identical pre, post, and retention tests. Students were also asked to name specific behaviors they could use to decrease the risk of diabetes. Responses were analyzed using Chi square analysis and content analysis. Overall, …


Fire, Soil, Native Species And Control Of Phalaris Arundinacea In A Wetland Recovery Project., Richard Douglas Foster May 2003

Fire, Soil, Native Species And Control Of Phalaris Arundinacea In A Wetland Recovery Project., Richard Douglas Foster

Electronic Theses and Dissertations

Southern Appalachian Phalaris arundinacea control was investigated by: 1) correlating cover and species richness with soil characteristics across transects; 2) burning and herbicide use to determine conditions facilitating native plant establishment; and 3) hemi-parasitic Pedicularis lanceolata tested as a biological control.

Phalaris cover was correlated with subsoil consolidation; areas without Phalaris had consolidated subsoil while Phalaris at >50% cover established on loose soil. Phalaris cover inhibited species richness (r2=0.78). No soil characteristic predicted species richness.

Herbicide reduced Phalaris cover and aerial biomass by 23% and 63% respectively, compared to controls. Burning was ineffective. Two summers after herbicide Phalaris …


The Effects Of Prescribed Fire On Millipede And Salamander Populations In A Southern Appalachian Deciduous Forest., Alison Baird Gagan Dec 2002

The Effects Of Prescribed Fire On Millipede And Salamander Populations In A Southern Appalachian Deciduous Forest., Alison Baird Gagan

Electronic Theses and Dissertations

Prescribed fire has increased as a forest management practice in southern Appalachia, but investigations into the effects of this silvicultural treatment on non-game wildlife inhabiting the region is limited. This study investigated the effects of prescribed fire on millipede and salamander populations. Seventeen sites within the Cherokee National Forest in east Tennessee that were treated once with prescribed fire between 1998 and 2002 were examined in the spring of 2002. Each burned plot was paired with an adjacent unburned plot.

The number of individual millipedes and salamanders collected from burned plots was compared to the corresponding control plot. Millipedes declined …


A Comparison Of Strength And Resistance Curves For The Internal And External Rotators Of The Shoulder., Daniel Cason Hannah Aug 2002

A Comparison Of Strength And Resistance Curves For The Internal And External Rotators Of The Shoulder., Daniel Cason Hannah

Electronic Theses and Dissertations

Progressive overload through the range of motion (ROM) is important for proper rehabilitation of muscle strength, yet varies across types of resistance for a given exercise. The purpose of this study was to compare strength curves (SC) for shoulder internal (IR) and external rotation (ER) with resistance curves (RC) for two application angles (A and B) of Thera-Band® resistance to determine which application angle best overloads IR and ER through the ROM. Thirty volunteer subjects participated in this study. SCs were obtained experimentally by measuring maximal isometric torque for IR and ER from 30° to 135°. RCs were calculated using …


An Experimental Approach To Teaching The Concept Of Functional Diversity., Cory Mckelvey Stanley May 2002

An Experimental Approach To Teaching The Concept Of Functional Diversity., Cory Mckelvey Stanley

Electronic Theses and Dissertations

This study tested an experimental approach to use in teaching the concept of functional diversity. The project culminated in a laboratory exercise for use in high schools.

Experimental design consisted of representatives of three functional groups of plants, (legumes, grasses, and forbs), planted singly, and in two, or three species combinations. Legumes were represented by Trifolium repens and Medicago lupulina, grasses were represented by Cynodon dactylon and Festuca rubra, and forbs were represented by Helianthus annus and Raphanus sativa.

Plants were grown inside a controlled growth chamber. During the growth phase, measurements were taken to highlight temporal …


Mannose And Lipopolysaccharide Receptors On The Surface Of Granular Hemocytes From The Crayfish Procambarus Clarkii., Gelu Dobrescu May 2002

Mannose And Lipopolysaccharide Receptors On The Surface Of Granular Hemocytes From The Crayfish Procambarus Clarkii., Gelu Dobrescu

Electronic Theses and Dissertations

Procambarus clarkii hemocytes have been shown to bind to both LPS and a mannose containing neoglycoprotein conjugated to fluorescent probes. A decrease in the observed number of fluorescent hemocytes indirectly indicated that the binding of FITC-LPS to these cells is impaired by initial incubation with LPS. Prior treatment of hemocytes with horseradish peroxidase, a mannose rich glycoprotein, decreased their capacity to bind mannose. Mannan had no inhibitory effect on the binding of either ligand. Mixed hemocytes and hemocyte subpopulations separated by buoyant density were incubated with both ligands and revealed that a subpopulation of granular hemocytes bound both LPS and …


A Prospective Design Identifying Etiological Risk Factors Associated With Mtss And Stress Fractures In Female Intercollegiate Athletes., Michael H. Blackburn May 2002

A Prospective Design Identifying Etiological Risk Factors Associated With Mtss And Stress Fractures In Female Intercollegiate Athletes., Michael H. Blackburn

Electronic Theses and Dissertations

The identification of risk factors associated with overuse injuries, specifically Medial Tibial Stress Syndrome (MTSS) and Tibial Stress Fractures (TSF), may help professionals with management and prevention of these injuries. The purpose of this study was to identify risk factors associated with MTSS and TSF in female intercollegiate athletes. This study used a mulitifactorial, prospective design for 13-26 weeks. Thirty-nine Division I intercollegiate female student-athletes in volleyball, soccer, and track were examined. Anatomical, physiological (eating disorder and menstrual history), and training (duration and recovery time) characteristics were examined as possible risk factors. Only two injuries were reported during the study; …


Marine Interstitial Tardigrades And Other Meiofauna Of Huntington Beach, South Carolina., Michael Scott Gaugler May 2002

Marine Interstitial Tardigrades And Other Meiofauna Of Huntington Beach, South Carolina., Michael Scott Gaugler

Electronic Theses and Dissertations

At Huntington Beach, SC meiofauna distribution was investigated. The purpose of the study was to determine tardigrade species present and any significant differences in the distribution pattern. Meiofauna were analyzed to determine if there were significant differences in their distribution patterns in relation to abiotic variables.

Cores were taken in the intertidal zone along three elevations. Each core was divided into depth samples and was processed to remove meiofauna. Each taxon (>1500 specimens) and tardigrades was statistically analyzed using three-way ANOVA to compare distribution patterns.

There were eighteen taxa identified and an estimated 330,338 specimens. The seven dominant taxa …


Breaking Seed Dormancy In Three Poaceae Species, Heidi Jo Larson Jan 2002

Breaking Seed Dormancy In Three Poaceae Species, Heidi Jo Larson

Electronic Theses and Dissertations

Seed dormancy is a major impediment to germination testing in seed testing laboratories. Dormant seeds are alive but do not germinate under conditions favorable for germination of non-dormant seeds of the same species. Dormancy in many p􀊆ant species can be broken using a single ·treatment or a combination of treatments. Treatments commonly used are light or dark, various temperature regimes, prolonged exposure to cold treatments (pre-chilling), and the use of growth hormones or other chemicals. Three Poaceae species, winter wheat (Triticum aestiivum), prairie drop seed V (Sporobolus heterolepis), and prairie cordgrass (Spartina pectinata), were the subject …


Use Of High Pressure Liquid Chromatography To Detect And Quantify Oxytetracycline Marks In Walleye Otoliths And Dorsal Spines, Michael J. Hawkins Jan 2002

Use Of High Pressure Liquid Chromatography To Detect And Quantify Oxytetracycline Marks In Walleye Otoliths And Dorsal Spines, Michael J. Hawkins

Electronic Theses and Dissertations

Oxytetracycline (OTC) is used to chemically mark calcified structures in walleye Stizostedion vitreum fry and fingerlings. Current visual methods for detection of these marks are subjective, and biologists are unable to quantify the amount of OTC in a sample. The goal of this study was to determine if high pressure liquid chromatography (HPLC) is a feasible and superior alternative for detecting and quantifying OTC in otoliths of fry-marked and spines of fingerlingmarked walleyes. Study objectives were to validate methodology of extraction of OTC from calcified tissue, detect and quantify extracted OTC using HPLC, and determine a cost comparison of current …


The Influence Of Stand Density On Rate Of Carbon Sequestration In Loblolly Pine Plantations On Mined Lands In East Texas, Jason Morton Jan 2002

The Influence Of Stand Density On Rate Of Carbon Sequestration In Loblolly Pine Plantations On Mined Lands In East Texas, Jason Morton

Electronic Theses and Dissertations

The State of Texas emits more carbon dioxide (C02) into the atmosphere than any other state in the United States. With environmental concerns escalating, the U.S. may be forced to reduce its emissions of greenhouse gases. The first target of these reductions will likely be utility companies that utilize coalfired power plants. In order to mitigate CO2 emissions, utility companies may want to either purchase carbon credits which can be obtained through carbon sequestration on NIPF lands or manage reclaimed mined lands for maximum carbon sequestration. This study determined the financially optimal planting density and management regimes for loblolly pine …


Comparison Of Black And White Elderly Women On Muscle Mass Bone Mineral Density And Balance., Tyanez Jones Dec 2001

Comparison Of Black And White Elderly Women On Muscle Mass Bone Mineral Density And Balance., Tyanez Jones

Electronic Theses and Dissertations

Few studies have compared balance between aging black (BW) and white women (WW) and examined its relationship to muscle mass and bone mineral density (BMD). Nineteen BW and 56 WW between 60-91 years participated. Upper and lower body strength, body composition, BMD, volitional and non-volitional control of dynamic balance, and physical activity ratings were assessed. There were no differences in strength between the groups. A trend was reported for total body BMD (p=0.07). WW exhibited better control of rapid volitional movements, in the limits of stability and rhythmic weight shift tests. The relationships of strength and muscle mass to BMD …


Examining The Effects Of Deer Antler Velvet Supplementation On Muscular Strength, Performance, And Markers Of Delayed Onset Muscle Soreness., Robyn Suzanne Percival Dec 2001

Examining The Effects Of Deer Antler Velvet Supplementation On Muscular Strength, Performance, And Markers Of Delayed Onset Muscle Soreness., Robyn Suzanne Percival

Electronic Theses and Dissertations

Purpose: To examine the effects of deer antler velvet on muscular strength, performance, and markers of delayed onset muscle soreness following a 10-week resistance training period.

Participants: 16 resistance-trained males (18-35) volunteered.

Measures: DEXA, 1-RM, a power test, and a 70% performance trial were measured. Creatine kinase and self-reported soreness levels were measured following an eccentric trial.

Results: No pre-experimental significant differences existed between the groups for any of the variables measured. There were no significant differences between the groups regarding body composition, strength, muscular performance, or improvements in creatine kinase and soreness levels from pre to post-intervention. Both groups …


Iron Acquisition In Rhodococcus Erythrolpolis: The Isolation Of Mutant(S) That Do Not Produce A Siderophore., Jaishree M. Vellore Dec 2001

Iron Acquisition In Rhodococcus Erythrolpolis: The Isolation Of Mutant(S) That Do Not Produce A Siderophore., Jaishree M. Vellore

Electronic Theses and Dissertations

Rhodococcus, a soil bacterium, displays a diverse range of metabolic capabilities with a number of potential practical applications. To exploit the metabolic potential of Rhodococcus, their basic physiology, genetics, and especially the acquisition of essential nutrients like iron, must be understood.

R. erythropolis strain IGTS8 releases a small compound called a siderophore, that scavenges ferric iron from the environment. To learn more about the genetic control of iron acquisition, mutant(s) defective in siderophore production were isolated. Mutants were generated, by inserting a mutagenic plasmid, pJCS506, into the bacterial cell using electroporation. The plasmid, which cannot replicate in these …


Antibiotic Resistance: Multi-Drug Profiles And Genetic Determinants., Lashan Denise Taylor Dec 2001

Antibiotic Resistance: Multi-Drug Profiles And Genetic Determinants., Lashan Denise Taylor

Electronic Theses and Dissertations

Antimicrobial susceptibility profiles were assembled for isolates of Moraxella catarrhalis collected from the Mountain Home Veteran's Affairs Medical Center (VAMC) clinical laboratory in Johnson City, Tennessee. The goal of the study was to identify isolates for genetic characterization using comparisons of susceptibility profiles. Isolates of Moraxella catarrhalis collected from July 1984 through 1994 were analyzed for β-lactamase production using a Cefinase disk assay.

A multi-drug profile consisting of 11 β-lactam antibiotics was performed on the 41 M. catarrhalis isolates. Kirby Bauer disk assays were performed for 7 cephalosporin and 4 non-cephalosporin antibiotics.

In summary, 2 observations implicate more complex resistance …


The Detection Of Morphological Variation Across Time In Two Roan Mountain Endemics: Geum Radiatum And Houstonia Montana., Dalenia Medford Aug 2001

The Detection Of Morphological Variation Across Time In Two Roan Mountain Endemics: Geum Radiatum And Houstonia Montana., Dalenia Medford

Electronic Theses and Dissertations

Morphological variation between geographically distant populations has long been recognized. The primary objective of this study was to test whether nonrandom shifts in morphology have occurred across a 150-year time span in two rare, endangered plant species Geum radiatum and Houstonia montana. During the last century the vegetation on Roan Mountain has undergone numerous environmental pressures that may have produced morphological shifts.

A diverse suite of morphological characters was measured from both species. Characters included vegetative and reproductive structures. Herbarium specimens and direct field measurements were the sources of material used. Results indicated a significant increase in size across …


Survey And Comparison Of Amphibian Assemblages In Two Physiographic Regions Of Northeast Tennessee., Marquette Elaine Crockett Aug 2001

Survey And Comparison Of Amphibian Assemblages In Two Physiographic Regions Of Northeast Tennessee., Marquette Elaine Crockett

Electronic Theses and Dissertations

Declines in amphibian populations have prompted study of their ecology and distribution. The purpose of this study was to survey two sites located within different physiographic and one herpetofaunal region of Northeast Tennessee, comparing species composition and activity. The first, Henderson Wetland, is in the Appalachian Ridge and Valley physiographic region. The second, John's Bog, is in the Blue Ridge. Survey methods included random walks, aural surveys, and point source collections during a 16-month period (February 1999 to May 2000).

Nine caudate (Plethodontidae) and one anuran species (Ranidae) were found in John's Bog. Seven caudate (Ambystomatidae, Plethodontidae, Salamandridae) and five …


The Impact Of Logging On Aquatic Salamander Communities., Heather Noel Mcdonald Aug 2001

The Impact Of Logging On Aquatic Salamander Communities., Heather Noel Mcdonald

Electronic Theses and Dissertations

For this study, the abundance of the salamander fauna in two streams was compared to determine the impact of logging activities. After five months of study, the area around one stream was logged by the National Forest Service. Following logging, the abundance of salamanders in the stream was greatly reduced, while the population in the undisturbed stream remained relatively unchanged. Six abundant species were used as indicators; two of these species (Desmognathus quadramaculatus and Desmognathus ochrophaeus) were negatively affected by the logging, while four species (Demognathus fuscus, Desmognathus monticola, Eurycea wilderae, and Gyrinophilus porphyriticus …


Genetic Diversity And Camptothecin Variation In Camptotheca Decaisne, Yuiie Wang Jul 2001

Genetic Diversity And Camptothecin Variation In Camptotheca Decaisne, Yuiie Wang

Electronic Theses and Dissertations

Camptotheca Decaisne is the major source of the promising anti-cancer alkaloids camptothecins. The main objectives of this study are (1) to reveal the genetic diversity of Camptotheca and to identify taxa with RAPD markers; (2) to determine the camptothecin (CPT) variations within and among different populations and taxa, with tissues, season, and age; and (3) to determine the effects of environmental stress on the camptothecin production in Camptotheca. RAPD markers provide a powerful tool for the identification of some populations (particularly cultivars) and the detection of genetic variation within Camptotheca. Three primers (OPA02, OPA03, and OPA04), generating 44 polymorphic bands …


A Comparison Of The Effects Of Interval Training Vs. Continuous Training On Weight Loss And Body Composition In Obese Pre-Menopausal Women., Jeffrey Warren King May 2001

A Comparison Of The Effects Of Interval Training Vs. Continuous Training On Weight Loss And Body Composition In Obese Pre-Menopausal Women., Jeffrey Warren King

Electronic Theses and Dissertations

The purpose of this study was to investigate the role exercise intensity plays in reducing body weight and percent body fat in overweight women. Subjects were randomized to either a high intensity interval training group (IT) or a lower intensity steady state training group (ST). Each group exercised 3 times per week for 8 weeks and expended 300 kcal per exercise session. VO2max, body composition, and resting metabolic rate (RMR) were measured pre and post training. RMR was measured after exercise at week 2 to see if intensity levels affected RMR. VO2max and body composition improved …


The Effects Of Parental Age And Housing Type On The Reproductive Success Of The Purple Martin (Progne Subis Subis), Jessica A. Eads May 2001

The Effects Of Parental Age And Housing Type On The Reproductive Success Of The Purple Martin (Progne Subis Subis), Jessica A. Eads

Electronic Theses and Dissertations

The reproductive success of the Purple Martin is dependent upon many factors. This study measured reproductive success of the Purple Martin (Progne subis subis) based on parental age and type of housing used. Reproductive parental ages consist of adults (experienced breeders) and subadults (first time breeders). Housing types included in this study were aluminum housing, wooden housing, plastic gourds, natural gourds, SuperGourds, and mailbox housing. The reproductive success was defined as the percentage of the original clutch that fledged. Study sites were located in Alabama, Indiana, North Carolina, Oklahoma, Tennessee, and Virginia. Pairs mating nonassortatively by age group …


The Cardiovascular Effects Of Resistance Exercise Training On Orthostatic Intolerance In Elderly Individuals., Lynn P. Rhea May 2001

The Cardiovascular Effects Of Resistance Exercise Training On Orthostatic Intolerance In Elderly Individuals., Lynn P. Rhea

Electronic Theses and Dissertations

One of the age-related changes associated with normal aging is the inability to maintain normal blood pressure homeostasis, a common clinical condition known as orthostatic intolerance. There are little data on the effects of strength training in healthy adults and orthostatic intolerance, and only one study on strength training and elderly adults diagnosed with orthostatic intolerance. Therefore, the purpose of the present study was to evaluate the effects of resistance training on the cardiovascular respones of elderly individuals during an orthostatic challenge.

Thirteen subjects were assigned to either a resistance (RES; n=7; 66±5 yrs.) or a control (CON; n=6; 71±6 …


The Status And Distribution Of The Topeka Shiner Notropis Topeka In Eastern South Dakota, Carmen M. Blausey Jan 2001

The Status And Distribution Of The Topeka Shiner Notropis Topeka In Eastern South Dakota, Carmen M. Blausey

Electronic Theses and Dissertations

The Topeka shiner Notropis topeka is a small (< 75 mm) minnow that inhabits prairie streams in several north central plains states. Once widespread and abundant throughout its historic range, the Topeka shiner is now found only in isolated populations. Because of an 80% reduction in occurrence throughout their range, the U.S. Fish and Wildlife Service listed the Topeka shiner as endangered in January 1999. At the time, limited information on habitat preferences and dist1ibution existed for this species in South Dakota. The objectives of this study were to measure local habitat features and water quality conditions at the reach scale at Topeka shiner study sites, create a model using these data to determine favorable habitat conditions, and identify fish species commonly associated with Topeka shiners. Fish and habitat data were collected at 61 tributary sites of the James, Vermillion, and Big Sioux rivers from June through September in 1999 and 2000. Sample sites in 1999 were based on historic Topeka shiner records in the South Dakota Natural Heritage Database. Sample sites in 2000 were based on a draft GIS model identifying potential Topeka shiner streams. Fish were collected with seines between block nets and standard procedures were used to measure physical and hydrological features of stream reaches. Cyprinids dominated the fish community for each river basin during both sample years. Insectivores and omnivores were the dominant trophic classes for each river basin for both sample years. Fish community associations for Topeka shiners were based on two stepwise logistic regression models: abundance of individual species at each site and presence or absence of individual species at each site. The abundance model indicated that Topeka shiners were most commonly associated with orangespotted sunfish Lepomis lutrenis and tadpole madtoms Noturns gyrinus. The presence/absence model showed that Topeka shiners were typically associated with red shiners Notropis lutrenis, tadpole madtoms Noturns gyrinus, black bullheads Ameiurus melas, and bigmouth shiners Notropis dorsalis. Habitat preferences were based on three stepwise logistic regression models: physical habitat water quality, and substrate composition at the reach scale. The physical habitat model indicated that Topeka shiners are associated with stream reaches that had low animal use, overhanging vegetation, stream bank vegetation comprised of sedges/rushes, low depositional zones, and run macrohabitat. The water quality model did not indicate any favorable or preferred conditions. The substrate model indicated that Topeka shiners are associated with stream reaches that had fine gravel or cobble substrates. The results of my study will lead to a better understanding of Topeka shiner distribution and habitat, and aid federal and state agencies in making management decisions that provide for protection and preservation of this species.


Measures Of Denitrification In Selected South Dakota Semi-Permanent Prairie Pothole Wetlands, Beverly S. Klein Jan 2001

Measures Of Denitrification In Selected South Dakota Semi-Permanent Prairie Pothole Wetlands, Beverly S. Klein

Electronic Theses and Dissertations

Wetlands are an integral part of agricultural systems in the prairie pothole regions of the North Central United States and Canadian Provinces. Little research has been done on denitrification in prairie potholes, and a better understanding of their denitrifying capability could aide in optimizing management practices near pothole areas. Most probable number (MPN) and denitrifying enzyme activity (DEA or Phase I) assays were conducted. Most probable number (MPN) measures were used to give an estimate of dissimilatory nitrate reduction to ammonia (DNRA) and denitrifying populations present in the wetlands. This study involved 3 selected semi-permanent prairie pothole wetlands near Madison, …


Invertebrate Egg And Plant Seed Banks In Natural, Restored, And Drained Wetlands In The Prairie Pothole Region (Usa) And Potential Effects Of Sedimentation On Recolonization Of Hydrophytes And Aquatic Invertebrates, Robert Andrew Gleason Jan 2001

Invertebrate Egg And Plant Seed Banks In Natural, Restored, And Drained Wetlands In The Prairie Pothole Region (Usa) And Potential Effects Of Sedimentation On Recolonization Of Hydrophytes And Aquatic Invertebrates, Robert Andrew Gleason

Electronic Theses and Dissertations

Sediment is the major pollutant of wetlands, lakes, rivers, and estuaries in the United States and it poses unique threats to wetlands of the Prairie Pothole Region (PPR). Sediment may impact the success of wetland restorations because burial of invertebrate and plant propagules may impact hatching and germination success, and hence, may hamper successional changes throughout interannual climate cycles. Sedimentation also reduces the pool depth and volume, further exacerbating the recovery of hydrophyte communities in restored wetlands. I evaluated the potential impacts of sedimentation on prairie wetlands from several perspectives. First, I evaluated the effects of sedimentation on loss of …


Early Instar Growth And Survivorship In The Common Baskettail Dragonfly Epitheca Cynosura (Anisoptera: Corduliidae)., Bryan Arthur Reece Aug 2000

Early Instar Growth And Survivorship In The Common Baskettail Dragonfly Epitheca Cynosura (Anisoptera: Corduliidae)., Bryan Arthur Reece

Electronic Theses and Dissertations

Egg masses of Epitheca cynosura were collected from Bays Mountain Park, Tennessee, USA, in June, 1999. Newly hatched individuals were placed into enclosures and sampled at scheduled time intervals throughout the summer. Enclosures were exposed to combinations of high and low densities and presence/absence of a second-year class E. cynosura predator. Survivorship, mean head widths, and mean dry masses were compared across treatments. Due to poor recovery of early-instar larvae, survivorship showed no significant differences in mortality among treatments. The predator present treatment caused significantly smaller head widths and dry masses only on days 42 and 55. The density treatment …


Characterization Of 50s Ribosomal Subunit Assembly Inhibition In Erythromycin Treated Escherichia Coli Cells., Jerry Edward Usary Aug 2000

Characterization Of 50s Ribosomal Subunit Assembly Inhibition In Erythromycin Treated Escherichia Coli Cells., Jerry Edward Usary

Electronic Theses and Dissertations

Erythromycin has long been recognized for its ability to inhibit protein synthesis by interfering with mRNA translation on the bacterial ribosome. We have recently shown that erythromycin also inhibits the assembly of the 50S ribosomal subunit in growing bacterial cells. The nature of this assembly inhibition has been investigated using 3H-uridine pulse-chase labeling of control and erythromycin treated E. coli cells.

Subunit assembly was examined by sucrose gradient centrifugation of labeled cell lysates. Normal assembly kinetics of subunit assembly were observed in control cells at 37°C. Formation of the 30S subunit was completed by 7.5 minutes and assembly of …


Signaling Mechanisms For Muscarinic Receptor-Mediated Coronary Vasoconstriction In Isolated Rat Hearts, Yi Zhang Aug 1999

Signaling Mechanisms For Muscarinic Receptor-Mediated Coronary Vasoconstriction In Isolated Rat Hearts, Yi Zhang

Electronic Theses and Dissertations

The signaling mechanisms for muscarinic receptor-mediated vasoconstriction in coronary resistance arteries were studied in KCl-arrested isolated rat hearts perfused at a constant flow rate. The cholinergic agonists acetylcholine and bethanechol were given by bolus injection or constant infusion. The coronary vascular resistance was monitored by measuring the changes in perfusion pressure. The selective muscarinic agonist bethanechol caused a similar vasoconstrictor response as ACh, but with less potency and efficacy. Bolus injection of bethanechol evoked a phasic vasoconstriction in a dose-dependent manner, while infusion of bethanechol evoked a tonic vasoconstriction without producing tachyphylaxis. Coronary vascular responses to bethanechol were further examined …