Digital Commons Network^™

The Genetics Of Speciation By Reinforcement, Daniel Ortiz-Barrientos

LSU Doctoral Dissertations

Reinforcement occurs when natural selection strengthens behavioral discrimination to prevent costly interpopulation matings, such as when matings produce sterile hybrids. This evolutionary process can complete speciation, thereby providing a direct link between Darwin’s theory of natural selection and the origin of new species. My dissertation presents the first study on the genetics of reinforcement. This study is framed in a conceptual body that explains how genomic architecture, selection and recombination, interact to facilitate divergence in the presence of gene flow. In addition, in my dissertation I produced a dense recombination map for D. pseudoobscura, which together with the genome sequence …

Health And Lifestyle Profiles Across The Lifespan: Results From The Louisiana Healthy Aging Study, Madlyn Irene Frisard

LSU Doctoral Dissertations

Aging and age related disease affects individuals differently. One possible explanation could be free radical production varies among individuals and this variation determines the aging process and the progression of disease. The purpose of this study was to test whether nonagenarians have a relatively low metabolic rate when compared to younger individuals and whether this low metabolic rate is associated with lower levels of oxidative stress and less incidence of disease. Resting metabolic rate (RMR), markers of oxidative stress to lipids, proteins, and DNA, components of the metabolic syndrome, and physical activity level were measured in 3 groups of individuals …

Alu Retrotransposition-Mediated Genomic Variation Within The Primate Order, Pauline Ann Callinan

LSU Doctoral Dissertations

Retrotransposons are an active family of mobile elements within primate genomes and the Short INterspersed Element (SINE) Alu is the most abundant member. These non-autonomous elements are responsible for introducing genomic diversity on an intra- and inter- species level that is useful in studies of forensic identity, population genetics, and evolutionary biology. In a computational survey of the human sex chromosomes, 344 recently integrated Alu elements were detected and subjected to empirical testing by polymerase chain reaction to determine presence/absence polymorphism. Sixteen elements were found to be polymorphic on the X chromosome, and only one polymorphic element on the Y …

Amino Acid Requirements And Low Crude Protein, Amino Acid Supplemented Diets For Swine And Poultry, Dustin Wade Dean

LSU Doctoral Dissertations

The purpose of this research was to determine requirements for amino acids that limit the use of crystalline amino acids, to determine the effects of reducing crude protein, and to evaluate the problems associated with low crude protein diets for swine and poultry. Four experiments were conducted to determine the Lys and sulfur amino acid requirements for 5- to 10-kg pigs. The results of these experiments suggest pigs in this weight range require a diet containing 1.40% true digestible (TD) Lys and the ratio of sulfur amino acids to Lys is not greater than 0.54. Two experiments were conducted to …

The Role Of Urease In The Pathogenesis Of Edwardsiella Ictaluri, Natha Joy Booth

LSU Doctoral Dissertations

An Edwardsiella ictaluri strain with disruption of ureG was identified through the use of signature tagged insertion mutagenesis as being attenuated for virulence in the channel catfish host. Sequencing of the flanking regions surrounding the insert showed that the gene was part of a urease gene complex that included ureE, ureF, ureG, ureD, ureI, and an ammonium transporter homologue. The ureG gene encodes a GTP-binding accessory protein which is thought to function in energy-dependent urease assembly. The ureG mutant strain was found to be attenuated for mortality, persistence, and for the ability to establish infection in a competition challenge during …

This Corner Of Canaan: Curriculum Studies Of Place And The Reconstruction Of The South, Reta Ugena Whitlock

LSU Doctoral Dissertations

If place is crucial to understanding the self and society, then it is central to curriculum studies that relate the individual and the social. This theoretical autobiographical research seeks to encourage progressive conversation and social political movement in the South by attending to the anomalous forms of Southernness that emerge in the interrogation of feeling Southern. Toward that end, in this dissertation I explore and foreground a marginalized Southern curriculum of nostalgia, homeplace, grace, and queerness. I investigate aspects of Southern place and feeling Southern that are submerged in conventional white patriarchal notions of Southern identity. My narrative allows some …

Macroinvertebrate Community Of Ecology Of Lowland, Subtropical Streams In Louisiana, Michael Douglas Kaller

LSU Doctoral Dissertations

Freshwater ecosystems, particularly streams and rivers, have been the subject of prodigious research. Unfortunately, in comparison to neighboring regions, the Gulf of Mexico coastal plain has not received as much attention. Therefore, I collected data on the macroinvertebrates of these streams to begin the understanding of the relationships between community structure and environmental characteristics. In contrast to the hypothesized ancestral streams of these macroinvertebrates, coastal plain streams are commonly devoid of rocks leaving only woody debris as usable hard substrates and are typically lower in dissolved oxygen. I examined habitat selection by colonization of woody debris with large and small …

The Language And Politics Of Place: Autobiographical Curriculum In The American South, Michael Brian Casemore

LSU Doctoral Dissertations

Place is central to the study of the American South. The question of the meaning and power of place underpinned the earliest efforts to define and understand the region, and place remains a crucial concept in an ongoing process of regional identification and inquiry. This study explores southern place autobiographically, historically, and theoretically in order to illuminate the subjective and social dimensions of place and to promote progressive conversation in the region. My inquiry is interdisciplinary. It draws on psychoanalysis, Southern studies, and the philosophy of place-as well as on theories of curriculum, literature, and art. If places can inspire …

The Psychosocial Vulnerability Model Of Hostility As A Predictor Of Coronary Heart Disease, Karen Grothe

LSU Doctoral Dissertations

Coronary heart disease (CHD) is the number one killer for both men and women in the United States today. African Americans are particularly at risk, due to higher prevalence rates and mortality related to CHD (American Heart Association, 2003). Less than half of the new cases of CHD can be predicted with known risk factors (tobacco use, obesity, hypertension), which suggests the possible influence of personality or additional behavioral factors. Hostility is a psychological variable that has been consistently related to health outcomes, particularly to CHD. While the exact mechanism linking hostility to health is currently unknown, a psychosocial vulnerability …

Effects Of Body Size On Goose Behavior: Lesser Snow Goose And Ross's Goose, Jon Einar Jonsson

LSU Doctoral Dissertations

Body size is highly variable among geese, both at intra- and interspecific levels. Interspecific variation in several behaviors has been attributed to differences in body size in geese: incubation constancy, tendency to maintain family units, and time spent foraging. Body size has important physiological implications for birds, mostly because mass-specific metabolic rate is greater for birds of smaller mass. The Body-size Hypothesis predicts that smaller species deplete their energy reserves at relatively faster rates than do larger species. Hypotheses and conclusions concerning effects of body size on waterfowl behavior often are based on comparisons of species that confront different climates, …

Development And Characterization Of Antimicrobial Edible Films From Crawfish Chitosan, Kandasamy Nadarajah

LSU Doctoral Dissertations

Inherent antibacterial/antifungal properties and film-forming ability of chitosan make it ideal for use as a biodegradable antimicrobial packaging material. This study was attempted to develop antimicrobial films from crawfish chitosan. Traditional chitosan production involves: deproteinization (DP), demineralization (DM), decolorization (DC), and deacetylation (DA). Modification of chitosan production affects film properties. Effects of chitosan production protocols, film-casting solvents, and plasticizer contents on physicochemical, mechanical and antibacterial properties were investigated. Four chitosans were prepared from traditional (DPMCA) and modified processes [excluding either DP, DC or both DP and DC]. Chitosan (1%w/v) was dissolved in 1% acetic, ascorbic, citric, formic, lactic and/or malic …

Host-Parasite Cophylogeny And Rates Of Evolution In Two Rodent-Louse Assemblages, Jessica E. Light

LSU Doctoral Dissertations

Studies of cophylogeny greatly increase understanding of associations between hosts and their parasites. This study uses molecular data to test the hypothesis that members of two rodent families (Geomyidae and Heteromyidae) and their associated lice (Geomydoecus and Fahrenholzia, respectively) show a statistically significant pattern of cophylogeny. Both host groups are generally solitary organisms and both louse groups are obligate ectoparasites, often exhibiting extreme degrees of host specificity. This intimate and potentially long-term association likely has resulted in coevolutionary adaptations and counter adaptations on the part of both symbiotic partners. Phylogenetic analysis of chewing lice (Geomydoecus) reveals two major clades corresponding …

Feature Essay, James D. Hardy

Civil War Book Review

Trials and Tribulations

Two Books offers insight into court cases

Fragile Fiber3, An Arabidopsis Gene Encoding A Type Ii Inositol Polyphosphate 5-Phosphatase, Is Required For Secondary Wall Synthesis And Actin Organization In Fiber Cells, Ruiqin Zhong, David H. Burk, W. Herbert Morrison, Zheng Hua Ye

Faculty Publications

Type II inositol polyphosphate 5-phosphatases (5PTases) in yeast and animals have been known to regulate the level of phosphoinositides and thereby influence various cellular activities, such as vesicle trafficking and actin organization. In plants, little is known about the phosphatases involved in hydrolysis of phosphoinositides, and roles of type II 5PTases in plant cellular functions have not yet been characterized. In this study, we demonstrate that the FRAGILE FIBER3 (FRA3) gene of Arabidopsis thaliana, which encodes a type II 5PTase, plays an essential role in the secondary wall synthesis in fiber cells and xylem vessels. The fra3 mutations caused a …

Three Distinct Suppressors Of Rna Silencing Encoded By A 20-Kb Viral Rna Genome, Rui Lu, Alexey Folimonov, Michael Shintaku, Wan Xiang Li, Bryce W. Falk, William O. Dawson, Shou Wei Ding

Faculty Publications

Viral infection in both plant and invertebrate hosts requires a virus-encoded function to block the RNA silencing antiviral defense. Here, we report the identification and characterization of three distinct suppressors of RNA silencing encoded by the ≈20-kb plus-strand RNA genome of citrus tristeza virus (CTV). When introduced by genetic crosses into plants carrying a silencing transgene, both p20 and p23, but not coat protein (CP), restored expression of the transgene. Although none of the CTV proteins prevented DNA methylation of the transgene, export of the silencing signal (capable of mediating intercellular silencing spread) was detected only from the F 1 …

High-Threshold, Kv3-Like Potassium Currents In Magnocellular Neurosecretory Neurons And Their Role In Spike Repolarization, Talent Shevchenko, Ryoichi Teruyama, William E. Armstrong

Faculty Publications

We identified Kv3-like high-threshold K+ currents in hypothalamic supraoptic neurons using whole cell recordings in hypothalamic slices and in acutely dissociated neurons. Tetraethylammonium (TEA)-sensitive currents (TEA) evoked from -50 I/V were characterized by a large component that inactivated in 10-30 ms, and a smaller, persistent component that inactivated in 1-2 s. UV relations in dissociated neurons revealed TEA-subtracted currents with a slope and voltage dependency consistent with the presence of Kv3-like channels. In slices, tests with 0.01-0.7 mM TEA produced an IC50 of 200-300 nM for both fast and persistent currents. The fast transient current was similar to currents associated …

Membrane Lipid Biosynthesis In Chlamydomonas Reinhardtii: Ethanolaminephosphotransferase Is Capable Of Synthesizing Both Phosphatidylcholine And Phosphatidylethanolamine, Wenyu Yang, James V. Moroney, Thomas S. Moore

Faculty Publications

Phosphatidylethanolamine, but not phosphatidylcholine, is found in Chlamydomonas reinhardtii. A cDNA coding for diacylglycerol: CDP-ethanolamine ethanolaminephosphotransferase (EPT) was cloned from C. reinhardtii. The C. reinhardtii EPT appears phylogenetically more similar to mammalian aminoalcoholphosphotransferases than to those of yeast and the least close to those of plants. Similar membrane topography was found between the C. reinhardtii EPT and the aminoalcoholphosphotransferases from mammals, yeast, and plants. A yeast mutant deficient in both cholinephosphotransferase and ethanolaminephosphotransferase was complemented by the C. reinhardtii EPT gene. Enzymatic assays of C. reinhardtii EPT from the complemented yeast microsomes demonstrated that the C. reinhardtii EPT synthesized both …

Tropospheric Ozone In Louisiana And Synoptic Circulation, Robert Rohli

Faculty Publications

Abstract Tropospheric ozone (O3) is a pollutant of increasing concern in many urban areas in the United States. There is an increasing need to understand the geographical and meteorological properties associated with O3, particularly because of the changing criteria that are being implemented by the U.S. Environmental Protection Agency to monitor O3. This research examines the relationship between O3 mixing ratios in Louisiana and surface and low-tropospheric synoptic circulation patterns. Results suggest that local conditions and synoptic influences are both important in determining the behavior of observed O3 in Louisiana during this period in which “exceedance” frequencies decreased until 2000–01, …

Louisiana Agriculture Fall, 2004, Lsu Agcenter

Louisiana Agriculture

No abstract provided.

Defining A Link With Asthma In Mice Congenitally Deficient In Eosinophils, James J. Lee, Dawn Dimina, Mi Mi P. Macias, Sergei I. Ochkur, Michael P. Mcgarry, Katie R. O'Neill, Cheryl Protheroe, Ralph Pero, Thanh Nguyen, Stephania A. Cormier, Elizabeth Lenkiewicz, Dana Colbert, Lisa Rinaldi, Steven J. Ackerman, Charles G. Irvin, Nancy A. Lee

Faculty Publications

Eosinophils are often dominant inflammatory cells present in the lungs of asthma patients. Nonetheless, the role of these leukocytes remains poorly understood. We have created a transgenic line of mice (PHIL) that are specifically devoid of eosinophils, but otherwise have a full complement of hematopoietically derived cells. Allergen challenge of PHIL mice demonstrated that eosinophils were required for pulmonary mucus accumulation and the airway hyperresponsiveness associated with asthma. The development of an eosinophi-less mouse now permits an unambiguous assessment of a number of human diseases that have been linked to this granulocyte, including allergic diseases, parasite infections, and tumorigenesis.

Sperm Cryopreservation Of A Live-Bearing Fish, The Platyfish Xiphophorus Couchianus, Changjiang Huang, Qiaoxiang Dong, Terrence R. Tiersch

Faculty Publications

The objectives of this study were to evaluate the effects of cryoprotectant, osmotic pressure, cooling rate, equilibration time, and sperm-to-extender ratio, as well as somatic relationships of body length, body weight, and testis weight to sperm density in the platyfish Xiphophorus couchianus. Sperm motility and survival duration after thawing were significantly different between cryopreservation with dimethyl sulfoxide (DMSO) and glycerol, with the highest motility at 10 min after thawing obtained with 14% glycerol. With subsequent use of 14% glycerol as cryoprotectant, the highest motility after thawing was observed with Hanks' balanced salt solution (HBSS) across a range of 240-300 mOsm/kg. …

Test Of The Mechanotactile Hypothesis: Neuromast Morphology And Response Dynamics Of Mechanosensory Lateral Line Primary Afferents In The Stingray, Karen P. Maruska, Timothy C. Tricas

Faculty Publications

The mechanotactile hypothesis proposes that ventral non-pored lateral line canals in the stingray function to facilitate localization of prey that contact the skin during benthic feeding. This study used comparative neurophysiological and morphological techniques to test whether ventral non-pored canals encode the velocity of skin movements, and show other adaptations that may enhance detection of tactile stimuli from their prey. Resting discharge rate of lateral line primary afferent neurons was lower among units from ventral than dorsal canal groups. The ventral non-pored canals had a higher proportion of silent units (31%) than either ventral (3%) or dorsal (13%) pored canals, …

The Chlamydomonas Reinhardtii Proteins Ccp1 And Ccp2 Are Required For Long-Term Growth, But Are Not Necessary For Efficient Photosynthesis, In A Low-Co2 Environment, Steve V. Pollock, Davey L. Prout, Ashley C. Godfrey, Stephane D. Lemaire, James V. Moroney

Faculty Publications

The unicellular green alga Chlamydomonas reinhardtii acclimates to a low-CO2 environment by modifying the expression of a number of messages. Many of the genes that increase in abundance during acclimation to low-CO2 are under the control of the putative transcription factor Cia5. C. reinhardtii mutants null for cia5 do not express several of the known low-CO2 inducible genes and do not grow in a low-CO2 environment. Two of the genes under the control of Cia5, Ccp1 and Ccp2, encode polypeptides that are localized to the chloroplast envelope and have a high degree of similarity to members of the mitochondrial carrier …

Feature Essay, David Madden

Civil War Book Review

Warring egos

Laughter and applause indicated

The Slave Power: Its Character, Career, And Probable Designs: Being An Attempt To Explain The Real Issues Involved In The American Contest, James L. Huston

Civil War Book Review

The dismal science and American slavery

19th century analysis of King Cotton

Membrane Lipid Biosynthesis In Chlamydomonas Reinhardtii: Expression And Characterization Of Ctp:Phosphoethanolamine Cytidylyltransferase, Wenyu Yang, Catherine B. Mason, Steve V. Pollock, Tracey Lavezzi, James V. Moroney, Thomas S. Moore

Faculty Publications

CTP:phosphoethanolamine cytidylyltransferase (ECT) is considered to be the regulatory enzyme in the CDP-ethanolamine pathway of phosphatidylethanolamine (PE) biosynthesis. The ECT cDNA of Chlamydomonas reinhardtii encodes a protein of 443 amino acid residues, which is longer than the same protein in yeast, rat or human. The translated product of cloned cDNA was expressed as a fusion protein in Escherichia coli, and was shown to have ECT activity. The deduced amino acid sequence has 41% identity with that of human or rat, and 30% with yeast. The ECT protein has a repetitive internal sequence in its N-and C-terminal halves and a signature …

Low Levels Of Nucleotide Diversity In Crocodylus Moreletii And Evidence Of Hybridization With C. Acutus, David A. Ray, Jennifer A. Dever, Steven G. Platt, Thomas R. Rainwater, Adam G. Finger, Scott T. Mcmurry, Mark A. Batzer, Brady Barr, Peter J. Stafford, Jenna Mcknight, Llewellyn D. Densmore

Faculty Publications

Examinations of both population genetic structure and the processes that lead to such structure in crocodilians have been initiated in several species in response to a call by the IUCN Crocodile Specialist Group. A recent study used microsatellite markers to characterize Morelet's crocodile (Crocodylus moreletii) populations in north-central Belize and presented evidence for isolation by distance. To further investigate this hypothesis, we sequenced a portion of the mitochondrial control region for representative animals after including samples from additional locales in Belize, Guatemala and Mexico. While there is limited evidence of subdivision involving other locales, we found that most of the …

Visualizing Chromosome Structure/Organization, Eric Lam, Naohiro Kato, Koichi Watanabe

Faculty Publications

With the rapid development of sequencing technologies in the past decade, many eukaryotic genomes have been resolved at the primary sequence level. However, organization of the genome within nuclei and the principles that govern such properties remain largely unclear. Optimization of fluorescence probe-based hybridization technologies combined with new advances in the instrumentation for microscopy has steadily yielded more structural information on chromosome organization in eukaryote model systems. These studies provide static snapshots of the detailed organization of chromatin. More recently, the successful application of a chromatin tagging strategy utilizing auto fluorescent fusion proteins opened a new era of chromatin studies …

Genetic Analysis Of The Herpes Simplex Virus Type 1 Ul20 Protein Domains Involved In Cytoplasmic Virion Envelopment And Virus-Induced Cell Fusion, Jeffrey M. Melancon, Timothy P. Foster, Konstantin G. Kousoulas

Faculty Publications

The herpes simplex virus type 1 UL20 protein (UL20p) is an important determinant for cytoplasmic virion morphogenesis and virus-induced cell fusion. To delineate the functional domains of the UL20 protein, we generated a panel of single and multiple (cluster) alanine substitutions as well as UL20p carboxyl-terminal truncations. The UL20 mutant genes could be broadly categorized into four main groups: Group I UL20 mutant genes complemented for both virus production and virus-induced cell fusion; Group II UL20 mutant genes did not complement for either virus-induced cell fusion or infectious virus production; Group II UL20 mutant genes complemented for virus-induced cell fusion …

Louisiana Agriculture Summer, 2004, Lsu Agcenter

Louisiana Agriculture

No abstract provided.