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The Mode Of Action Of Intersex In Terminal Sexual Differentiation In Drosophila., Robert Russel Risley

Student Work

The intersex gene (2-60.5) lies at the terminus of the regulatory pathway that determines sex-type in Drosophila. Its product functions with the female-specific product of doublesex, another gene in the self-determination regulatory pathway, to regulate female-specific differentiation. However, the mechanism of this regulation has not been clearly demonstrated. Using a temperature-sensitive allele at intersex to eliminate its function at time points both during development and in the adult stage, the mode by which intersex regulates female determination was addressed. When chromosomal females bearing a temperature-sensitive intersex allele are raised at a permissive temperature, they develop as phenotypic females. Animals raised …

Plant Species Distribution Along Topographic Gradients In Tallgrass Prairies Of Eastern Nebraska., Ghanim A. S. Abbadi

Student Work

Plant species composition was evaluated along a slope gradient in two native tallgrass prairies of eastern Nebraska. Forb cover differed significantly (P<0.05) along the topographic gradient at both sites, however, grass covered differed only at one site (P<0.05). A site-by-site comparison by topographic location indicates significant differences between lower slopes for grass and between upper slopes for forbs. Big bluestem (Andropogon gerardii Vitman) dominated all topographic locations at both sites (average cover = 64%) with no significant differences in the topographic distribution. Kentucky bluegrass (Poa pratensis L.), little bluestem (Andropogon scoparius Michx.), false boneset Kuhnia eupatorioides L.) prairie wild rose (Rosa arkansana Porter), prairie violet (Viola pedatifida G. Don), and sedge (Carex L. spp.) also show the no significant topographic preference at either site. Mid-slope locations contained the greatest number of species that differed significantly along the topographic gradient. Leadplant (Amorpha canescens Pursh) and indiangrass (Sorghastrum nutans (L.) Nash) were the two most common species showing high canopy cover values in mid-slope locations at both sites. Significant topographic distributions were also noted for scoring rush (Equisetum lawvigatum A. Br.) at both sites and for finger coreopsis (Coreopsis palmata Nutt.) found only at one site. Flowering spurge (Euphobia corollate L.) and sideoats grama (Bouteloua curtipendula (Michx.) Torr.) were significantly higher on the hilltop locations of one site.

Identification And Characterization Of Tdd-1 And Related Retrotransposons In Dictyostelium., Gail A. Henderson

Student Work

Previous studies in Dictyostelium discoideum on the transposable element Tdd-1, have identified two transcription units of opposite polarity. One is a major, developmentally regulated 4.5 kb transcript believed to encode proteins involved in the retrotransposition of this element, and the other, 1.4 kb in size, is a heat-shock inducible RNA. Based on the sequence of the 4.5 kb transcript and the encoded amino acid sequence, it has been proposed that Tdd-1 is a retrotransposon. This implies that the 4.5 kb mRNA is copied by reverse transcriptase, resulting in DNA copies that insert into new sites. The purpose of this study …

Genetic And Molecular Analyses Of Host Symbiotic Genes And An In Vitro Regeneration System For Cicer Arietinum L, Vijayashri Ganapathy Paruvangada

Doctoral Dissertations

Ineffectively nodulating plant mutants PM405B, PM638A, and PM796B were used in molecular/genetic analyses of root nodule formation in chickpea. To establish the mode of inheritance of the mutant nodule phenotype in chickpea mutant PM638A, reciprocal crosses were made between PM638A and wild-type ICC640. The F$\sb2$ segregation data fit a 3 mutants: 1 wild-type monohybrid phenotypic ratio, indicating that ineffective nodulation is due to a monogenic dominant, nuclear mutation, tentatively designated as "Rn$\sb7$". Segregation analysis of F$\sb3$ progeny confirmed this model.

Early (ENod2) and late (Lb) nodulin cDNAs were used as heterologous probes to identify and study the expression of corresponding …

Studies On Hepatitis A Virus: I. Expression Of Viral Capsid Peptides In Escherichia Coli And Their Application For An Immunoassay. Ii. Development Of An Assay For Viral Detection By Anti-Hav Antibodies., Luis Antonio Baez

LSU Historical Dissertations and Theses

A panel of eleven monoclonal antibodies of the IgG and IgM class were developed against the HM 175 strain of the Hepatitis A virus. Immunoglobulin specificity for the Hepatitis A virus was determined and the antibodies were applied toward the development of an antigen capture assay linked to a nucleic acid amplification step (RT-PCR), for detection of the Hepatitis A virus. The neutralizing mouse monoclonal antibody and a rabbit polyvalent serum were assessed as capture antibodies for the immunoaffinity stage of the assay. Fifty microliter microfuge tubes were coated with the capture antibody. Formalin inactivated HAV was diluted to concentrations …

Comparisons Of Spontaneous Mutation Rates And Estimates Of Numbers Of Cell Divisions In The Germlines Of Three Metazoans., Joni Boncille Drost

LSU Historical Dissertations and Theses

Germline mutation rates measured per generation per locus in three species of Metazoa are used to address questions of the constancy of mutation rates per generation, per year and per germcell division. Null mutation rates per generation are: 3.6 $\times$ 10$\sp{-6}$ for human X-linked disease, 8.9 $\times$ 10$\sp{-6}$ for Specific Locus Test (SLT) in male mice, 3.2 $\times$ 10$\sp{-6}$ for SLT in female mice, 8.0 $\times$ 10$\sp{-6}$ for SLT in male Drosophila melanogaster (D.m.), 1.6 $\times$ 10$\sp{-6}$ for SLRL test in male D.m. and 2.0 $\times$ 10$\sp{-6}$ for SLRL test in female D.m. They were found to be very similar …

The Role Of Flagellar Proteins In Adhesion Of Vibrio Parahaemolyticus, And Isolation Of The Corresponding Gene(S)., Ratchanee Hongprayoon

LSU Historical Dissertations and Theses

Polar flagellar core protein was purified from Vibrio parahaemolyticus by differential centrifugation and cesium chloride isopycnic centrifugation. Twelve hybridomas secreting monoclonal antibodies against flagellar core protein (MAb-flc) were obtained from fusions. By chance, one purified flagellar core preparation retained flagellar sheath and as a consequence, two hybridomas were detected which secreted anti-sheath antibodies (MAb-fls). MAb-flc and MAb-fls reacted specifically with their corresponding antigens as demonstrated by immunogold labelling. Coagglutination reagents prepared with MAb-flc and MAb-fls were tested against 34 strains of V. parahaemolyticus and 34 heterologous Vibrio species. The coagglutination results revealed that the flagellar core was species-specific while the …

Contributions Of Monoclonal Antibodies With Anti-Neural Cell Adhesion Molecule Like Activity To Peripheral Nerve Regeneration., Laura G. Remsen

LSU Historical Dissertations and Theses

Tubes containing monoclonal antibodies with anti-neural cell adhesion molecule (N-CAM)-like activity were applied to transected sciatic nerves to attempt to perturb the recovery of muscle function. Physiological recordings were used to estimate the return of function. The decline of implanted antibody over 28 days was estimated. No significant immune responses were detected in response to the implanted material. Electron microscopic and immunohistological analyses evaluated particular cellular disruptions in nerves due to the presence of these antibodies with anti-N-CAM like activity. Histological sections of fixed experimental nerves consistently revealed abnormal gaps between Schwann cells of regenerating nerves. This specific Schwann cell …

Genetic Population Structure Of A Species Complex Of Blue Mussels (Mytilus Spp.)., Shane Kevin Sarver

LSU Historical Dissertations and Theses

Mussels representing two species (Mytilus trossulus and M. galloprovincialis) were collected from 28 littoral locations on the Pacific coast of the USA, and examined for genetic variation at 15 allozyme loci. Eleven samples from a region of suspected hybridization between the two species were also analyzed for variation in seven shell characters. Analysis of allozyme data by principal components analysis revealed three groups based on first principal component scores, and were identified as M. trossulus, M. galloprovincialis and hybrids. Canonical discriminate analysis of seven shell characters was less successful in separating mussels based on morphological criteria alone. To explore the …

Interaction Between Hydrodynamics And Sediment Topography On Meiofaunal Abundance And Distribution., Bin Sun

LSU Historical Dissertations and Theses

The objective of this dissertation was to investigate the small-scale spatial and abundance patterns of meiofauna and their relationship with sediment microtopography and hydrodynamics. Meiofauna are known to be aggregated at small spatial scales. A study was first undertaken to determine, how patchiness differed over seasons and habitats. Significant small-scale aggregations were remarkably consistent across different seasons and habitats for all abundant copepods of an intertidal mudflat. Spatial autocorrelation analysis showed that the abundance of copepods was autocorrelated at short distances (cm scale) on all sample collecting dates, indicating a consistent spatial pattern. Small-scale variation contributed heavily to the components …

Studies On The Energy Mobilizing Hormones In Insects., Subrata Das

LSU Historical Dissertations and Theses

Chemical factors controlling the energy mobilization in three species of insects were identified, partially characterized and their role in the process of energy mobilization were studied. High performance liquid chromatographic fractions were isolated from methanolic extracts of the corpora cardiaca (CC) from the honeybee Apis mellifera, the paper wasp Polistes exclamans and the house cricket Acheta domesticus. Each species had a single active fraction that was able to elevate the lipid titer in Acheta. Pyroglutamate aminopeptidase digestion of isolated active fractions indicated that these molecules are all peptides with a terminal pyroglutamate. Methanolic extracts of CC from Apis, Polistes and …

Physiological And Biochemical Responses To Hypoxia In The Blue Crab, Callinectes Sapidus Rathbun, The Lesser Blue Crab, Callinectes Similis Williams, And The Southern Oyster Drill, Stramonita Haemastoma Linnaeus., Tapash Das

LSU Historical Dissertations and Theses

This study measured the physiological and biochemical changes associated with exposure of the juvenile blue crab, Callinectes sapidus Rathbun and the lesser blue crab. C. similis Williams, to long term (28 d) hypoxia, short term (10 d) transfer from hypoxia to normoxia and a diurnally fluctuating oxygen regime for 28 days. The southern oyster drill, Stramonita haemastoma Linnaeus, was also exposed to 28 days of constant hypoxia to compare the responses of a tolerant species with the two species of Callinectes. The 28 day LC$\sb{50}$ estimates for C. sapidus, C. similis and S. haemastoma were respectively 106, 43 and 11.5 …

Structural Analysis And Methionine Ehancement Of The Bean Seed Storage Protein Phaseolin., John M. Dyer

LSU Historical Dissertations and Theses

Common beans are widely utilized as a food source, yet are limited as a complete source of protein due to low levels of methionine, an essential amino acid for humans. A protein engineering strategy was developed to increase the methionine content of phaseolin, the primary seed storage protein in common beans. The engineering strategy consists of three major parts. In the first part, a set of biophysical probes was developed to characterize the stability of wild-type and modified phaseolin proteins. I used absorbance, fluorescence emission, circular dichroism, and fluorescence polarization anisotropy to monitor phaseolin denaturation induced by urea, guanidinium chloride, …

Functional Morphology Of The Lingual Apparatus Of Sandgrouse (Aves: Pteroclidae)., Werner Muller

LSU Historical Dissertations and Theses

The morphology of the lingual apparatus of three species of sandgrouse (Aves; Pteroclidae) has been described. All biomechanically important parts were included in the description, i.e., all muscles potentially involved in the functioning of the lingual apparatus, all skeletal parts, the salivary glands associated with the lingual apparatus, and the surface morphology of the oropharyngeal cavity. For each muscle its potential functions have been described. In a comparison with data from the literature of three other groups of birds it was found that the functional organization of the lingual apparatus of the sandgrouse is strikingly similar to the one found …

Analysis Of Chromosomal Involvement In Yersinia Pestis Virulence Plasmid Expression, Teresa Sandelin Birrer

Doctoral Dissertations

Virulence plasmid expression in the Yersinia has been shown to vary depending upon which species harbors the virulence plasmid suggesting that chromosomal regulation may in some way be involved. In this study, fertility plasmid expression in Y. pestis was investigated as a means of evaluating mechanisms of virulence plasmid regulation in this bacterium. The F plasmid was found to be minimally expressed in Y. pestis transferring at a rate of 8.8 $\times$ 10$\sp{-5\%}.$ In addition, Y. pestis failed to express F pili as determined by infection with the male specific phage MS2. When F plasmids containing at least 2 E. …

Regulation Of The Yeast Transcriptional Activator Adr1, W James Cook

Doctoral Dissertations

Glucose repression of the ADH2 gene from Saccharomyces cerevisiae is mediated by the abundance and activity of the transcriptional activator ADR1. The focus of this dissertation is to characterize the mechanisms by which glucose controls the ability of ADR1 to activate ADH2 transcription.

Glucose results in a two-fold decrease in the steady state levels of ADR1 mRNA. This glucose-dependent reduction in steady state ADR1 mRNA was shown to be due to an increased rate of ADR1 mRNA degradation. The unusually long, 510 nucleotide 5$\sp\prime$ untranslated region of the ADR1 mRNA appeared to mediate this glucose-dependent ADR1 mRNA decay.

To better …

Light Detection System In Higher Plant Chloroplasts: Pigment Mediated Or Overall Photon Flux Density Related, Soumitra Ghoshroy

Doctoral Dissertations

Plants adapt to short term changes in irradiance and quality of the light environment by modulating the structure of the thylakoid membranes to make the best use of the available light energy. Shade-acclimated chloroplasts develop more thylakoid surface area as compared to those growing in full sunlight. Conversion of sun-type chloroplasts to shade-types and vice versa on the basis of total thylakoid membrane surface area can occur quickly. However, the response mechanism of chloroplasts to changes in light levels is yet to be understood. This short term light detection mechanism may be mediated by a pigment system other than photosynthetic …

Strawberry Malformation And The Tarnished Plant Bug, David Thomas Handley

Doctoral Dissertations

Experiments were designed to study the malformation of strawberries, Fragaria x ananassa (Duchesne) caused by the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois). In greenhouse experiments, duration of blossom exposure to tarnished plant bug affected the type of malformation observed. Exposure at anthesis for 48 hours was most likely to cause apical seediness, the malformation associated with tarnished plant bug. The number of nonviable achenes per fruit increased with longer feeding durations. Malformation was also affected by blossom stage. Prebloom feeding caused blossom death. Feeding at petal fall or achene separation resulted in malformations, including apical seediness. Feeding at …

A Multi-Scale Analysis Of The Population Ecology Of A Temperate Reef Fish, Phillip S. Levin

Doctoral Dissertations

Using field experiments and descriptive analyses this study investigated the significance of larval settlement and post-settlement processes to populations of cunner, Tautogolabrus adspersus. At small spatial scales there was no relationship between the density of new recruits and the percent cover of kelp, foliose algae and branching algae. Crustaceans and mussels were preferred found items of juvenile cunner, and significantly greater numbers of isopods, amphipods and newly settled mussels were present in patches where fish were present than in randomly selected patches.

Experimental and correlative analyses demonstrated that variation in recruitment could not be explained by the presence of conspecifics. …

Effects Of Hematopoietic Neoplasia On Physiological Processes In The Soft-Shell Clam, Mya Arenaria (Linne), Mary-Susan Potts

Doctoral Dissertations

Mya arenaria (L.) is susceptible to the disease, hematopoietic neoplasia (Hn), in which atypical cells invade the blood and connective tissue of the clam's organs. In this study impacts of Hn on the reproductive and excretory systems were examined in clams collected from New Bedford Harbor and Little Buttermilk Bay, Buzzards Bay, MA.

The relationships between Hn seasonality and reproduction were evaluated from fresh blood samples and histological analysis of gonads. Both clam populations had biannual reproductive cycles with spawnings in the spring and fall. Hn prevalence exhibited some seasonality with maxima in the fall and late winter-early spring. Reproductive …

Insertion Sequence Elements In Yersinia: Nucleotide Sequence Of Is100 Of Yersinia Pestis, Stephen Dale Torosian

Doctoral Dissertations

The World Health Organization classified (Williams, 1983) Y. pestis as Y. pseudotuberculosis subsp. pestis on the basis of DNA homology, yet the two organisms cause markedly different disease. Portnoy and Falkow (1981) reported IS100 to influence the virulence of Y. pestis. IS100 was shown to be found in Y. pestis but not Y. pseudotuberculosis.

IS100 from Y. pestis was sequenced and shown by sequence analysis to fulfill the requirements of being an IS element. pIS1C, an 821 bp fragment of IS100 was transferred to Y. pseudotuberculosis Trp-Ca-, resulting in the ability of the cells to ferment rhamnose and delayed production …

The Characterization Of The Orb Web Of Argiope Aurantia (Araneae: Araneidae) With Emphasis On The Major Ampullate Silk, Cathy Rose Tugmon

Doctoral Dissertations

The orb web of Argiope aurantia was partitioned into a water-soluble and insoluble fraction. The water-soluble fraction was composed of low molecular weight (LMW) molecules ($<$5 kDa) and middle molecular weight (MMW) molecules (14.3 kDa-29 kDa). Choline was one of the principal components of the LMW molecules. This study demonstrated that spiders, like many insects, are unable to synthesize choline from glucose. Attempts to sequence one of the purified MMW proteins were unsuccessful due to the blockage of the N-terminus.

The major emphasis of this research centered on the major ampullate silk of Argiope aurantia. Attempts were made to characterize this silk, both by direct amino acid sequencing and inference from the sequence of a cDNA library clone for one of the major ampullate silk proteins.

To isolate the progenitive silk from the lumen of the major ampullate gland, it was first necessary to inhibit the spider proteases which are known to cleave silk. …

Characterization And Inheritance Of The Fused Vein Trait In Squash (Cucurbita Pepo L), Robert Bruce Carle

Doctoral Dissertations

This investigation characterized and determined the inheritance of the fused vein trait in Cucurbita pepo L. with the purpose of evaluating its use as a rouging marker for hull-less seeded cultivars.

The trait is characterized by the partial fusion of the primary leaf veins. There is a reduction in the intraveinal leaf blade and the dorsal leaf surface appears wrinkled. Depending on genetic background, fusion begins with the fourth to tenth leaf stage and continues throughout vegetative growth. The extent of fusion also varies from slight (1-5 cm) to pronounced (15-20 cm). Anatomically, fusion results from an interruption of vein …

Silk Use During Proecdysis In The Spider Araneus Cavaticus (Araneae: Araneidae), Mark Anthony Townley

Doctoral Dissertations

Major ampullate (MaA) and minor ampullate (MiA) silk glands of juvenile Araneus cavaticus were examined by dissection at various times relative to ecdysis. Several days before ecdysis the single, larger pairs of MaA and MiA glands (termed 'primary' MaA and MiA glands) become non-functional and remain so until ecdysis. Nevertheless, proecdysial spiders are able to draw ampullate fibers due to the presence of smaller pairs of MaA and MiA glands (termed 'open secondary' MaA and MiA glands) which are functional at this time. It appears that these open secondary MaA and MiA glands are intended for use only during proecdysis. …

Characterization Of Activation And Inhibitory Regions In The Adr1 Transcriptional Regulator, Dan Chase

Doctoral Dissertations

The regulation of the ADH2 gene from the yeast Saccharomyces cerevisiae is carbon source-dependent. Expression of ADH2 requires the activity of the transcriptional activator ADR1. This dissertation addresses three separate aspects of the regulation of ADR1 activity.

We have identified eleven additional ADR1$\sp{c}$ mutations which allow ADH2 to partially escape glucose repression. These eleven new mutations cluster to one region of the ADR1 peptide between amino acids 227 and 239, previously identified by four other ADR1$\sp{c}$ mutations. These are the only mutations in ADR1 which have been isolated by virtue of their ability to activate ADH2 transcription under repressed conditions. …

Strongylus Vulgaris: Protection, Pathology And Humoral Immune Responses In The Immunized Pony., Clifton Michael Monahan

LSU Historical Dissertations and Theses

Protective resistance to Strongylus vulgaris infection was examined by immunization of ponies with radiation-attenuated larvae or soluble parasite homogenates. Twelve yearling ponies raised and maintained under parasite-free conditions were divided into four groups which received either radiation-attenuated L$\sb3$; aqueous-soluble adult somatic antigens plus adjuvant; aqueous-soluble larval somatic antigens with excretory/secretory products and adjuvant; or media with adjuvant. Ponies were immunized twice; radiation-attenuated L$\sb3$ were administered orally and soluble antigens or control injections were given intramuscularly. Six weeks following the second immunization, ponies were challenged per os with virulent S. vulgaris L$\sb3.$ Ponies were monitored twice daily for rectal temperatures and …

Photosynthetic Response To Elevated Carbon Dioxide Concentrations In The Aerenchyma Of Typha Latifolia L. Leaves., John Van Horne Constable

LSU Historical Dissertations and Theses

This study examined the importance of the leaf aerenchyma gas space as a CO$\sb2$ source for photosynthesis in Typha latifolia L. (broadleaf cattail). In the field there was a distinct diurnal pattern of CO$\sb2$ concentration ( (CO$\sb2$)) in the aerenchyma gas space. At dawn the aerenchyma (CO$\sb2$) was 4 to 18 times above atmospheric levels. By midday the aerenchyma (CO$\sb2$) declined to near atmospheric levels and increased again in the late afternoon. It is hypothesized that this diurnal pattern may be controlled by photosynthetic demand for CO$\sb2$. Aerenchyma gas space was estimated as $>$50% of leaf volume, and the …

Circadian Neuroendocrine Regulation Of Scale Allograft Reactions In Gulf Killifish, Fundulus Grandis., Nicholas John Nevid

LSU Historical Dissertations and Theses

Reactions against scale allografts in gulf killifish were studied to examine circadian variation and neuroendocrine regulation of immune function. Although melanophores in autografts remain viable indefinitely, melanophores in scale allografts were broken down predominantly at night (12-h scotophases) regardless of the time of transplantation. Daily treatment with hormones or antagonists of neuroendocrine receptors altered the rhythm of melanophore breakdown when administered at light onset or light offset. Daily rhythms of immune activity may be a direct reflection of growth hormone levels and are entrained by exogenous cortisol treatment. Daily nonphotoperiodic environmental stimuli overrode photoperiodic entrainment of immune activity. Peak melanophore …

Resolution Of Genotypic And Phenotypic Properties Of Herpes Simplex Virus Type 1 Temperature-Sensitive Mutanttsz47: Evidence For Allelic Complementation In The Unique Long Gene Ul28., James Daniel Cavalcoli

LSU Historical Dissertations and Theses

This research focuses on the phenotypic and genotypic characteristics of a temperature sensitive mutant of herpes simplex virus type 1, HSV-1 (tsZ47). This virus was previously reported to carry two different mutations, which caused it to be temperature sensitive for viral replication and transport of glycoproteins to the infected cell surface. However, altered glycoprotein transport to the cell surface was not observed in this study. In addition, cells transformed with unique long gene 28 (UL28), but not glycoprotein B (gB), complemented tsZ47 at the nonpermissive temperature indicating that a single mutation could restore the wild type phenotype to the mutant …

The Phylogeny Of The Prasinophyceae And Pleurastrophyceae (Chlorophyta) Inferred From Ribosomal Rna Genes And Morphology., Thomas Sinclair Kantz

LSU Historical Dissertations and Theses

The phylogeny of the problematic green algal classes Prasinophyceae and Pleurastrophyceae (Chlorophyta) sensu Mattox and Stewart (1984) was inferred from ultrastructural and biochemical data, and from ribosomal RNA gene sequence data. Analysis of a data set of ultrastructural and biochemical characters (with a predominance of flagellar and cell covering features) revealed a monophyletic Pleurastrophyceae and a monophyletic Prasinophyceae. Rerooting experiments indicated that the ancestral flagellate was likely Pedinomonas-like or Mamiellales-like. The cladograms generated from the ribosomal RNA gene sequence data show that the Pleurastrophyceae is not monophyletic; however, pleurastrophycean taxa are more closely related to the Chlorophyceae than to any …