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Biology: What One Needs To Know, Ursula Goodenough Dec 1996

Biology: What One Needs To Know, Ursula Goodenough

Biology Faculty Publications & Presentations

Biology on this planet represents an astonishing experiment in carbon-based chemistry which, over billions of years, has generated billions of species adapted to countless major and minor fluctuations in ecological circumstances. In one sense there is no way to generalize about biology. While biological activities can all be ultimately explained by physical laws (like everything else in the universe), it is the emergent intensely particular properties of organisms that most interest us. This essay represents an attempt to describe some of the more prominent patterns that emerge from the sea of biological particularities, patterns that present many opportunities for religious …


An Analysis Of Two Tests For Diesel Contamination In The Environment When Considering The Impact On Hydrocarbon Degrading Bacteria, Chris Wedding Dec 1996

An Analysis Of Two Tests For Diesel Contamination In The Environment When Considering The Impact On Hydrocarbon Degrading Bacteria, Chris Wedding

Mahurin Honors College Capstone Experience/Thesis Projects

No abstract provided.


Modeling Interactions Of Browsing Predation, Infaunal Activity And Recruitment In Marine Soft-Sediment Habitats, Sara M. Lindsay, David S. Wethey, Sarah A. Woodin Oct 1996

Modeling Interactions Of Browsing Predation, Infaunal Activity And Recruitment In Marine Soft-Sediment Habitats, Sara M. Lindsay, David S. Wethey, Sarah A. Woodin

Faculty Publications

In marine soft-sediment habitats, the sediment surface is altered by activities of sediment dwellers (infauna). Such biogenic disturbance can influence recruitment success if settling larvae and juveniles avoid disturbed sites or if juveniles die as a result of disturbance after settling. Because infauna commonly lose exposed body parts to browsing predators and disturb less sediment as a result, we developed a simulation model to examine the interactions between browsing predation, infaunal adult activity, and recruitment. Sediment disturbance in the model was based on data for the polychaete Abarenicola pacifica. We simulated the activity of two general types of predators: prey …


The Spatial Distribution Of A Transcript Of A Drosophila Octopamine/Tyramine Receptor., Laura M. Mckay Aug 1996

The Spatial Distribution Of A Transcript Of A Drosophila Octopamine/Tyramine Receptor., Laura M. Mckay

Student Work

Two specific receptor subtypes for octopamine, a biogenic amine found in both vertebrates and invertebrates, have been pharmacologically defined in insects. These receptors mediate responses involved in the regulation of movement, feeding and mating behaviors by inducing a rise in intracellular cAMP levels via adenylate cyclase stimulation or by increasing intracellular calcium levels via an undetermined mechanism. Recent studies on a putative octopamine/tyramine Drosophila receptor cDNA permanently expressed in mammalian cells have suggested the existence of an additional novel octopamine receptor subtype. This receptor binds multiple agonists (i.e. octopamine and tyramine) and can differentially couple to two different secondary messenger …


Characterization Of An Octopamine Receptor Gene In Drosophila Melanogaster., Kelley Lynn Colvin Aug 1996

Characterization Of An Octopamine Receptor Gene In Drosophila Melanogaster., Kelley Lynn Colvin

Student Work

The biogenic amine octopamine is a versatile signaling molecule that acts in essential physiological functions in invertebrates. Its roles in neurotransmission, neurohormone regulation and neuromodulation are achieved through interaction with G-protein coupled receptors. Such invertebrate receptors are structurally and functionally analogous to vertebrate adrenergic receptors. A human brain β2-adrenergic receptor cDNA clone was used as a hybridization probe to identify a Drosophila gene encoding an octopamine/tyramine receptor. This 367 base pair fragment of Drosophila genomic DNA, homologous to the putative sixth and seventh transmembrane regions of adrenergic receptors, was used to isolate an octopamine/tyramine receptor 3.3 Kb cDNA clone from …


A Comparison Of Vegetation In Restored And Natural Wetlands In The Nebraska Sandhills., Warren Thomas Weaver Jul 1996

A Comparison Of Vegetation In Restored And Natural Wetlands In The Nebraska Sandhills., Warren Thomas Weaver

Student Work

Plant composition was compared between 3 restored and 3 natural Nebraska sandhill wetlands using plot data collected from each wetland in July and August of 1995 along five randomly placed, 25m transects. A total of 126 species were identified, of which 72 were found only in the natural area and 23 only in the restored area; the natural wetlands average 58 species and their restored 31. Cluster analysis of mean cover values, at a Euclidean Distance of 1000, identified five vegetative associations in the natural and three in the restored wetlands. In addition, cluster analysis of combined data indicated a …


The Effects Of Selected Lichen Extracts And Purified Compounds On The Rat Heart., Richard C. Witt Jul 1996

The Effects Of Selected Lichen Extracts And Purified Compounds On The Rat Heart., Richard C. Witt

Student Work

Extracts from Letharia vulpina, Umbilicaria americana, Cladina subtenuis, Xanthoparmelia cumberlandia, Rimelia reticulata, and Parmotrema austrosinense were used to study their electrophysiological effects on rat heart ventricular tissue. Additionally, solutions of four purified lichen metabolites ---- vulpinic acid, usnic acid, stictic acid, and atranorin ---- were studied in the same manner. The action potential duration at 50% and 90% of repolarization was significantly reduced by two of the extracts and metabolites, those containing vulpinic acid and usnic acid and the purified forms of those compounds. A positive relationship between the effects of extracts and purified compounds was exhibited. These data suggest …


1: "To Know Ourselves", The U.S. Department Of Energy, The Human Genome Project Jul 1996

1: "To Know Ourselves", The U.S. Department Of Energy, The Human Genome Project

Genomics: Past & Future

AT THE END OF THE ROAD in Little Cottonwood Canyon, near Salt Lake City, Alta is a place of near-mythic renown among skiers. In time it may well assume similar status among molecular geneticists. In December 1984, a conference there, co-sponsored by the U.S. Department of Energy, pondered a single question: Does modern DNA research offer a way of detecting tiny genetic mutations—and, in particular, of observing any increase in the mutation rate among the survivors of the Hiroshima and Nagasaki bombings and their descendants? In short the answer was, Not yet. But in an atmosphere of rare intellectual fertility, …


Abundant Protein-Containing Particles In The Sea, Richard A. Long, Farooq Azam Jun 1996

Abundant Protein-Containing Particles In The Sea, Richard A. Long, Farooq Azam

Faculty Publications

The interaction of bacteria with particulate organic matter has implications for organic matter cycling and bacterial ecology in the ocean. Until recently, the focus has been on 'classical' particles visible by unaided eye (marine snow) or light microscopy. Recent discoveries of several new types of abundant particles, from sub-micrometer to sub-marine snow, are changing our ideas of the physical and chemical nature of the particle field with which pelagic bacteria interact. Previous workers have discovered polysaccharide-containing (Alcian Blue stainable) transparent exopolymer particles (TEP) ranging from 3 to 100s of micrometers. Looking for additional components of the sub-marine snow particle field, …


Settlement And Early Post-Settlement Survival Of Sessile Marine Invertebrates On Topographically Complex Surfaces: The Importance Of Refuge Dimensions And Adult Morphology, Linda J. Walters, David S. Wethey Jun 1996

Settlement And Early Post-Settlement Survival Of Sessile Marine Invertebrates On Topographically Complex Surfaces: The Importance Of Refuge Dimensions And Adult Morphology, Linda J. Walters, David S. Wethey

Faculty Publications

We predicted that both refuge dimension and growth form would influence settlement and short-term post-settlement success (≤7 d) of sessile marine invertebrates that live attached to hard substrata in low energy environments. Individuals with unlimited attachment to the substrata should rapidly be protected by their growth form, thus decreasing their need to settle in refuges and limiting the length of time any locations on heterogeneous substrata act as refuges. Alternatively, organisms with limited attachment to the substrata should remain susceptible to the causes of mortality for a longer time, and as a result should settle in high quality refuges (sites …


The Effects Of Hypoxic Conditions On Dictyostelium Mucoroides., Mary E. Kosinski May 1996

The Effects Of Hypoxic Conditions On Dictyostelium Mucoroides., Mary E. Kosinski

Student Work

Previously a transcript corresponding to a gene in Dictyostelium mucoroides designated A-11 was found in amoebae during vegetative growth and macrocyst formation. The derived amino acid sequence of A-11 was used to search Genbank to find homologous proteins. The highest degree of homology was found with a hemoglobin from the bacterium Vitreoscilla. The Vitreoscilla hemoglobin protein showed greater than 65% similarity and 50% identity with the A-11 amino acid sequence. It was reported that hypoxic conditions could stimulate the expression of the gene corresponding to the Vitreoscilla hemoglobin when cloned in E. coli cells.


A Molecular Analysis Of An Octopamine Receptor Gene In Drosophila Melanogaster., Pramodini Purushottam Rode May 1996

A Molecular Analysis Of An Octopamine Receptor Gene In Drosophila Melanogaster., Pramodini Purushottam Rode

Student Work

Octopamine is a biogenic amine. It plays an important role as neurohormone neuromodulator and neurotransmitter in Drosophila melanogaster. These physiological functions of octopamine are essential in feeding, mating and fight-or-flight behavior. Octopamine receptors are structurally and fundamentally similar to the vertebrate adrenergic receptors. A Drosophila gene encoding an octopamine/tyramine receptor was previously identified by probing a Drosophila genomic library with a human brain β2 adrenergic receptor cDNA clone. After identifying a 367-bp fragment of a Drosophila genomic DNA, a cDNA library prepared from head mRNA was screened and a 3.3 kb cDNA, containing the inferred protein coding region of the …


The Cloning And Characterization Of Toad-64: A Gene Expressed Transiently During Neuronal Differentiation In The Mammalian Nervous System, Jane Elizabeth Minturn May 1996

The Cloning And Characterization Of Toad-64: A Gene Expressed Transiently During Neuronal Differentiation In The Mammalian Nervous System, Jane Elizabeth Minturn

Yale Medicine Thesis Digital Library

During the development of the mammalian central nervous system, a pool of morphologically homogeneous, mitotically active progenitor cells in the neural tube gives rise to the enormously diverse population of postmitotic cells that assume the properties of neurons or glia. Postmitotic neurons elaborate processes that are involved in the migration of neurons to their adult positions as well as the elaboration of axonal and dendritic arbors that will ultimately form specific synaptic contacts. The generation of postmitotic neurons from precursor cells is a central differentiative event in development, but molecular markers of this event are few.Using 2D gel electrophoresis, proteins …


Effects Of High-Molecular-Weight Dissolved Organic Matter On Nitrogen Dynamics In The Mississippi River Plume, Wayne S. Gardner, Ronald Benner, Rainer M.W. Amon, James B. Cotner Jr., Joann F. Cavaletto, Jeffrey R. Johnson Mar 1996

Effects Of High-Molecular-Weight Dissolved Organic Matter On Nitrogen Dynamics In The Mississippi River Plume, Wayne S. Gardner, Ronald Benner, Rainer M.W. Amon, James B. Cotner Jr., Joann F. Cavaletto, Jeffrey R. Johnson

Faculty Publications

The dynamics of N and its interactions with labile dissolved organic C (DOC), bacteria, and phytoplankton were studied to determine potential effects of dissolved organic matter (DOM) and light on N dynamics in surface waters of the Mississippi River (USA) plume in the Gulf of Mexico. Bacterial uptake of added labeled N compounds ( 15NH4+ or 15N-labeled dissolved free amino acids. DFAA) was stimulated more by high-molecular-weight (HMW, >l kDa) DOM than by low-molecular-weight (LMW, < l kDa) DOM. An index that inversely indicated the presence of labile DOC was defined as the fraction of assimilated Amino acid-15N that was Recovered as 15N -Ammonium (ANRA), following the additions of high-levels (4 µM) of 15N -DFAA. …


Targeted Gene Replacement To Mimic Familial Hypertrophic Cardiomyopathy In Caenorhabditis Elegans, Craig Alan Almeida Jan 1996

Targeted Gene Replacement To Mimic Familial Hypertrophic Cardiomyopathy In Caenorhabditis Elegans, Craig Alan Almeida

Doctoral Dissertations

The identification in invertebrates of genes homologous to human disease genes provides the possibility to broaden the spectrum of model organisms to include experimental invertebrates. The goal of this study is to test the possibility of using Caenorhabditis elegans as an animal model for the inherited human heart disorder familial hypertrophic cardiomyopathy. In 10-30% of the affected families that have been studied, this disease is caused by mutations in the $\beta$-cardiac myosin heavy chain (MHC) gene. The most common of these mutations results in the replacement of an evolutionarily conserved arginine residue (R403) with glutamine (R403Q). While this information has …


The Biology And Ecology Of The Yellowmargined Leaf Beetle, Microtheca Ochroloma Stal, (Coleoptera: Chrysomelidae) On Crucifers., Abdullahi Olod Ameen Jan 1996

The Biology And Ecology Of The Yellowmargined Leaf Beetle, Microtheca Ochroloma Stal, (Coleoptera: Chrysomelidae) On Crucifers., Abdullahi Olod Ameen

LSU Historical Dissertations and Theses

The biology and ecology of the yellowmargined leaf beetle, Microtheca ochroloma Stal, were studied on cabbage, Brassica oleracea var capitata L., collard, B. oleracea var acephala L., mustard, B. juncea Cosson, turnip, B. rapa L., and radish, Raphanus sativus L. The life cycle of the beetle consists of an egg stage, four larval instars, prepupal, pupal and adult stages. There were no significant differences in the effect of host plant on duration of development of immature beetles (p = 0.3353). The mean duration of development from oviposition to adult emergence ranged from 26.6 d on turnip to 27.5 d on …


Community Structure And Habitat Preferences Of Intertidal Fishes Of The Eastern Canary Islands: Fuerteventura, Gran Canaria, And Lanzarote, With A Behavioral Description Of Mauligobius Maderensis (Osteichthyes: Gobiidae)., Richard Patrick Cody Jan 1996

Community Structure And Habitat Preferences Of Intertidal Fishes Of The Eastern Canary Islands: Fuerteventura, Gran Canaria, And Lanzarote, With A Behavioral Description Of Mauligobius Maderensis (Osteichthyes: Gobiidae)., Richard Patrick Cody

LSU Historical Dissertations and Theses

Community structure and relative habitat preferences of intertidal fishes from the eastern Canary Islands of Fuerteventura, Gran Canaria, and Lanzarote were examined in a study of 354 tidepools at 33 localities. Habitat use and behavior of the most abundant fish Mauligobius maderensis were examined on Gran Canaria and Lanzarote. Of the 27 species encountered, 11 were common to each of the islands. The most abundant species were: M. maderensis, Parablennius parvicornis, Gobius paganellus, Coryphoblennius galerita, and Chelon labrosus. In a Two-way indicator species analysis Fuerteventura and Lanzarote localities clustered together. The same analysis differentiated between species that inhabited the upper …


Importance Of A Siderophore In The Pathogenesis And Virulence Of Photobacterium Damsela Subsp. Piscicida In Hybrid Striped Bass (Morone Saxatili X Morone Chrysops)., John Phillip Hawke Jan 1996

Importance Of A Siderophore In The Pathogenesis And Virulence Of Photobacterium Damsela Subsp. Piscicida In Hybrid Striped Bass (Morone Saxatili X Morone Chrysops)., John Phillip Hawke

LSU Historical Dissertations and Theses

Photobacterium damsela subsp. piscicida, formerly Pasteurella piscicida, is an important new pathogen of hybrid striped bass cultured in brackish water on Louisiana mariculture farms. Louisiana isolates compared with strains of P. damsela subsp. piscicida from Greece, Japan, Israel and Chesapeake Bay, USA and were found to be identical in biochemical phenotype and enzymic activity. Small plasmids of 8 and 5 kb were unique to Louisiana strains. Sequential daily bacteriology and histopathology on hybrid striped bass experimentally infected by immersion revealed that following high doses (13,000 CFU/ml) the gills and spleen are colonized first as early as 24 hours PI, followed …


Cloning, Sequencing And Regulation Of The Rhodobacter Capsulatusheme Gene., Georgia Ineichen Jan 1996

Cloning, Sequencing And Regulation Of The Rhodobacter Capsulatusheme Gene., Georgia Ineichen

LSU Historical Dissertations and Theses

In Rhodobacter capsulatus, a purple nonsulfur bacterium, the tetrapyrrole pathway yields four end products: siroheme, vitamin B12, heme and bacteriochlorophyll. Growth of R. capsulatus under low oxygen tension increases carbon flow through the tetrapyrrole pathway up to 100 fold. The mechanism(s) for this regulation is currently unknown. One regulatory mechanism could be transcriptional control of one or more of the genes in the common portion of the tetrapyrrole pathway. The fifth gene in the pathway, hemE, has been cloned by complementation of an Escherichia coli hemE::miniTn10 mutant. Sequence data of hemE revealed the presence of an upstream palindrome that is …


The Role Of Seed Banks, Disturbance, And Sea Level Rise In Determining The Plant Community Structure Of Oligohaline Coastal Marshes., Andrew Hamilton Baldwin Jan 1996

The Role Of Seed Banks, Disturbance, And Sea Level Rise In Determining The Plant Community Structure Of Oligohaline Coastal Marshes., Andrew Hamilton Baldwin

LSU Historical Dissertations and Theses

Coastal wetlands worldwide are threatened by sea level rise, which is expected to affect the growth and survival of wetland vegetation by increasing water level and salinity. While the effects of salinity and inundation on adult vegetation of oligohaline marshes have been widely studied, the species composition of the seed bank and its response to elevated salinity and water level have not been examined. Additionally, the role of disturbances of different intensities in structuring marsh plant communities and possible interactions between disturbance and rising sea level have received little attention. Disturbances in coastal marshes include nonlethal disturbances such as fire …


Impacts Of Fire And Vertebrate Herbivores On Plant Community Characteristics And Soil Processes In A Coastal Marsh Of Eastern Louisiana, United States Of America., Mark Alan Ford Jan 1996

Impacts Of Fire And Vertebrate Herbivores On Plant Community Characteristics And Soil Processes In A Coastal Marsh Of Eastern Louisiana, United States Of America., Mark Alan Ford

LSU Historical Dissertations and Theses

Both vertebrate herbivores and fire have long been known to have dramatic and important effects on wetlands. In the first part of this study, conducted in the Pearl River Basin coastal marshes of Louisiana, the interaction between the effects of mammalian herbivores, especially nutria and wild boar, and fire was examined in three marsh community types: those dominated by Sagittaria lancifolia, Panicum virgatum, or Spartina patens/Scirpus americanus. Overall, above-ground biomass was reduced by burning but increased by fencing. Richness only increased in plots that were both burned and fenced. In the three communities, only Scirpus americanus cover was enhanced by …


Regulation Of Interrenal Steroidogenesis In Elasmobranchs., Brian Scott Nunez Jan 1996

Regulation Of Interrenal Steroidogenesis In Elasmobranchs., Brian Scott Nunez

LSU Historical Dissertations and Theses

This study investigated the steroidogenic enzymes of the elasmobranch interrenal. First, biochemical characteristics of cytochrome P450c21 hydroxylase (P450c21) and 3$\beta$-hydroxysteroid dehydrogenase (3$\beta$-HSD) were determined with incubations of the microsomal fraction of Carcharhinus limbatus (blacktip shark) interrenal tissue. Second, molecular reagents were obtained by isolating and sequencing partial cDNA clones encoding the elasmobranch steroidogenic enzymes cytochrome P450 side chain cleavage (P450scc) and 3$\beta$-HSD from blacktip shark and Daysatis americana (southern stingray) interrenal. Finally, the regulation of Daysatis sabina (Atlantic stingray) interrenal steroidogenesis by peptide hormones such as corticotropin (ACTH) and angiotensin II was investigated by in vitro incubations of interrenal tissue. …


Postexercise Hypotension (Peh) In The Dog: Possible Role Of Immune System Cytokines., Gerald Dwayne Thompson Jan 1996

Postexercise Hypotension (Peh) In The Dog: Possible Role Of Immune System Cytokines., Gerald Dwayne Thompson

LSU Historical Dissertations and Theses

This study investigated postexercise hypotension (PEH) in five normotensive dogs testing these hypotheses: (1) PEH is present in the dog model; (2) high intensity exercise of 85% HR$\rm\sb{max}$ as compared to moderate intensity exercise of 60% HR$\rm\sb{max}$ induces a greater PEH; and (3) IL-1 and its activation of PGE$\sb2$ are associated with PEH. In experiment I, it was found that 85% HR$\rm\sb{max}$ exercise decreased systolic blood pressure (SBP) and mean arterial blood pressure (MABP) at 30 and 60 minutes postexercise (p $<$ 0.05). Both IL-1 and PGE$\sb2$ increased immediately following intense exercise, although temporal patterns were dissimilar. During non-exercise infusion of ibuprofen or dexamethasone (experiment II), blood pressure was not affected, but ibuprofen led to an overall inhibition of PGE$\sb2$. However, dexamethasone infusion led to a significant increase in PGE$\sb2$ at 180 and 210 minutes postinfusion. In experiment IIIA, after intense exercise following ibuprofen or saline infusion, PGE$\sb2$ increased at 120 to 180 minutes postexercise. Similar results were noted after exercise during dexamethasone treatment (experiment IIIB). In experiment IIIA & B, neither ibuprofen nor dexamethasone significantly affected PEH, although non-significant reductions in PEH was observed in dexamethasone treated animals. However, PGE$\sb2$ significantly increased after exercise at time points when PEH was not observed. These data indicate that (1) the intensity of exercise may have an effect on PEH, (2) there is partial support for the involvement of IL-1 and PGE$\sb2$ in PEH due to their immediate increase after exercise although a direct relationship was not observed, and (3) IL-1 still remains a possible mechanism responsible for PEH because of trends for attenuated PEH and PGE$\sb2$ responses following dexamethasone treatment.


Ion Transport In The Freshwater Bivalve, Corbicula Fluminea (Muller)., Huiyuan Zheng Jan 1996

Ion Transport In The Freshwater Bivalve, Corbicula Fluminea (Muller)., Huiyuan Zheng

LSU Historical Dissertations and Theses

Corbicula fluminea (Muller) maintains hydromineral balance in dilute media by active transepithelial transport of Na and Cl. Cl uptake depended on external (Cl) and displayed saturable kinetics. The transport capacity in pondwater(PW)-acclimated animals was 7.00 $\pm$ 0.51 $\mu$eq(g dry tissue $\cdot$ h)$\sp{-1}$ and the transport affinity 0.21 $\pm$ 0.08 mM. Prolonged salt depletion increased Cl transport capacity without changing the affinity. In PW-acclimated C. fluminea, Na and Cl transport were independent, and were stimulated by serotonin. In salt depleted (SD)animals, Na transport was partially Cl-dependent but Cl transport was Na-independent. Acetazolamide increased Na and Cl efflux. Both serotonin and acetazolamide …


Role Of Hurricane Disturbance In The Dynamics Of The Southern Mixed Hardwood Forest: A Case Study In Northern Florida., William Bennett Batista Jan 1996

Role Of Hurricane Disturbance In The Dynamics Of The Southern Mixed Hardwood Forest: A Case Study In Northern Florida., William Bennett Batista

LSU Historical Dissertations and Theses

The objective of this dissertation was to characterize the role of hurricanes in the dynamics of old-growth Southern Mixed Hardwood Forests from the coastal plain of the northern Gulf of Mexico. First, we used data from five stands to describe the structure, composition, and disturbance regime of these forests. All five stands have Magnolia grandiflora and Fagus grandifolia among the dominant species, and have been affected by frequent but relatively mild hurricanes (4-6 per century, windspeed $<$200 km/h). Second, we examined the changes in tree recruitment, growth, and mortality occurred in Woodyard Hammock, northern Florida, after this forest was affected by Hurricane Kate in 1985. The analysis was based on data from biennial censuses of a 4.5 ha plot conducted between 1978 and 1992. Hurricane Kate produced extensive canopy disruption but limited tree mortality. This disturbance prompted a phase of increased recruitment, growth, and survival of understory trees, and decreased growth and survival of overstory trees. Release of small understory individuals appeared to be critical for the persistence of three short-lived dominant species, Pinus glabra, Ostrya virginiana and Carpinus caroliniana. However, persistence of the longer-lived dominants Magnolia grandiflora, Fagus grandifolia, Liguidambar styraciflua, Nyssa sylvatica, and Ilex opaca, appeared to depend primarily on resistance to hurricane damage. Third, we used matrix population models to test specific hypotheses about mechanisms of persistence of F. grandifolia in Woodyard Hammock. These models showed that, both before and after Hurricane Kate, this population was close to equilibrium. This result supported the hypothesis that persistence of F. grandifolia has resulted from hurricane resistance. Sensitivity analyses of the models suggested that the key for hurricane resistance has been the high survival of medium-size trees. Life-history strategies involving resistance and survival to hurricane disturbance, rather than release and rapid growth, appear to have been prevalent in these forests. However, the hurricane regime would have resulted in coexistence of species with the two types of strategy. Hurricanes would have been frequent enough to secure the persistence of species dependent on release, and mild enough not to compromise that of species dependent on resistance.


Molecular Systematics Of Red Algae., Jeffrey Craig Bailey Jan 1996

Molecular Systematics Of Red Algae., Jeffrey Craig Bailey

LSU Historical Dissertations and Theses

Phylogenetic analyses of nucleotide sequences for the nuclear-encoded small subunit ribosomal RNA (SSU) gene were used to test current hypotheses of relationships within the Corallinales and among the florideophycidaean orders of red algae. Analyses of SSU gene sequences indicate that the order Corallinales includes four major lineages. The Sporolithaceae is resolved as the earliest-diverging lineage within the order and forms the sister group to a monophyletic Corallinaceae. The molecular data also support the monophyly of the subfamilies Melobesioideae and Corallinoideae. The latter subfamily is inferred as sister to a fourth lineage including non-geniculate and geniculate species classified in the subfamilies …


Low Carbon Dioxide-Inducible Genes And Proteins In Chlamydomonas Reinhardtii., Zhi-Yuan Chen Jan 1996

Low Carbon Dioxide-Inducible Genes And Proteins In Chlamydomonas Reinhardtii., Zhi-Yuan Chen

LSU Historical Dissertations and Theses

At low CO$\sb2$ conditions, C. reinhardtii, like many other green algae, induces a CO$\sb2$ Concentrating Mechanism (CCM) to raise the internal Ci concentration. During the induction, at least five new polypeptides and six different genes are upregulated and some of the corresponding mRNAs or proteins are absent in high CO$\sb2$ requiring mutants. However the identities and functions of these genes are unknown. In this dissertation, I partially characterized four low CO$\sb2$ inducible genes and one low CO$\sb2$ inducible protein LIP-36. The complete cDNA sequences of clones 11I3 and 2I5 are 1311 bp and 985 bp, respectively. Neither of these two …


Physical And Functional Characterization Of Long Terminal Repeat Of Equine Infectious Anemia Virus., Soo Ho Kim Jan 1996

Physical And Functional Characterization Of Long Terminal Repeat Of Equine Infectious Anemia Virus., Soo Ho Kim

LSU Historical Dissertations and Theses

The U3 region of long terminal repeat (LTR) of equine infectious anemia virus (EIAV) contains transcriptional regulatory elements. To identify the elements in prototype (P), fetal donkey dermal cell-adapted (A), and two variant (V) EIAV LTRs, DNase I footprinting, gel shift, and transient gene expression assays were performed. The assays used U937 monocytic cells which can be induced into macrophages by 12-O-tetradecanoylphorbol-13-acetate (TPA). For study of AP1 sites, c-Jun/AP1 was also used. Footprinting with nuclear extracts from TPA-induced and uninduced U937 cells localized methylated DNA-binding protein (MDBP), PEA2, AP1, PU.1, and CCAAT enhancer-binding protein (C/EBP) sites as common elements in …


Relationship Of Critical Photoperiod Of Short-Day Parents To Frequency Of Day-Neutral Progeny In Short-Day X Day-Neutral Crosses Of Fragaria X Ananassa, Christina Marie Cundari Jan 1996

Relationship Of Critical Photoperiod Of Short-Day Parents To Frequency Of Day-Neutral Progeny In Short-Day X Day-Neutral Crosses Of Fragaria X Ananassa, Christina Marie Cundari

Doctoral Dissertations

Critical photoperiod for flowering was determined for short-day (SD) and day-neutral (DN) genotypes of strawberry used in SD x DN crosses to investigate whether variation in critical photoperiod contributes to variation in frequency of DN progeny and, hence, may be an effective selection criterion for screening SD genotypes for use as parents in breeding regionally-adapted DN cultivars. Twelve SD and four DN genotypes were grown in controlled environments under eight photothermal regimes (four photoperiods (9, 11, 13, 15 hr) x two day/night temperatures (19/14 and 24/19$\sp\circ$C)). Among the SD genotypes, critical photoperiod varied more under cool than warm regimes. Under …


The Purification And Characterization Of An Extrapallial Fluid Protein From The Mollusc, Mytilus Edulis, Stephen Joseph Hattan Jan 1996

The Purification And Characterization Of An Extrapallial Fluid Protein From The Mollusc, Mytilus Edulis, Stephen Joseph Hattan

Doctoral Dissertations

Shell deposition within the bivalve mollusc Mytilus edulis is regulated by the macromolecules of the extrapallial fluid (EP fluid). These mineralization regulating macromolecules are thought to be responsible for the nucleation, growth regulation and growth cessation of the CaCO$\sb3$ mineral crystals that will inevitable constitute $\geq$95% of the mature shell.

This dissertation presents the results of the purification and characterization of the major EP fluid protein of the bivalve Mytilus edulis. The major EP fluid protein was determined to comprise 56% of the total fluid protein and to consist of 7.25% by weight carbohydrate. The protein was purified though a …