Digital Commons Network^™

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, …

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 …

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 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.

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. …

Osteopontin (Opn): Structural Analysis Of The Mouse Opn Gene And Functional Analysis Of The Opn Protein In Malignancy, Elke Ingeborg Behrend

Digitized Theses

Osteopontin (OPN) is an integrin-binding cell adhesion protein, that is expressed in many normal cells and tissues, and that is associated with a number of pathological conditions, including cancer. The work presented in this thesis addresses both structural studies of the opn gene, and functional studies of the OPN protein, in an attempt to improve our understanding of OPN.;Two conflicting gene structures of the mouse opn gene had been reported that put into question the location of the promoter, the transcriptional start site, and exon 1 of the mouse opn gene. Analysis of the expressed messages predicted by the two …

Properties And Regulation Of The Calcium Ion Pump In Heart And Skeletal Muscle Sarcoplasmic Reticulum, Cynthia Elaine Hawkins

Digitized Theses

In heart and skeletal muscle, the sarcoplasmic reticulum (SR) plays a critical role in the contraction-relaxation cycle of the myocyte: a Ca{dollar}\sp{lcub}2+{rcub}{dollar} channel releases Ca{dollar}\sp{lcub}2+{rcub}{dollar} from SR into cytoplasm to trigger contraction, and a Ca{dollar}\sp{lcub}2+{rcub}{dollar} pump resequesters Ca{dollar}\sp{lcub}2+{rcub}{dollar} to cause relaxation. A major regulator of this cycle is {dollar}\rm Ca\sp{lcub}2+{rcub}{dollar}/calmodulin-dependent protein kinase (CaM kinase), which is known to phosphorylate and thereby activate the cardiac SR Ca{dollar}\sp{lcub}2+{rcub}{dollar} pump, Ca{dollar}\sp{lcub}2+{rcub}{dollar} channel and endogenous Ca{dollar}\sp{lcub}2+{rcub}{dollar}-pump inhibitor phospholamban. This thesis examines the Ca{dollar}\sp{lcub}2+{rcub}{dollar} pump and its regulation in different tissues (cardiac, slow-twitch and fast-twitch muscle SR: CMSR, SMSR and FMSR) and different stages in …

Human Placental Trophoblast As A Model For Tumor Progression, Nelson K. Khoo

Digitized Theses

The human placenta is comprised of extravillous trophoblast (EVT) cells which invade the uterus and its vasculature establishing maternal-fetal exchange of key molecules. The mechanisms of in vitro EVT cell invasiveness are similar to those of malignant tumor cells but are regulated in situ by locally derived factors. This invasiveness is insufficient for malignancy. The goal of this laboratory is to transform normal EVT cells and induce premalignant, malignant and/or metastatic phenotypes to identify genetic changes relevant to tumor progression.;Two SV40 T antigen (Tag) transformed cell lines (long lived RSVT-2; immortal RSVT2/C) derived from the invasive first trimester EVT cell …

Some Physiological Effects Of Stress In The American Cockroach Periplaneta Americana (L), Shigui Liu

Digitized Theses

The effects of different forms of stress on the American cockroach, Periplaneta americana (L.) have been systematically examined. This study demonstrated that at least two stress-related events occurred in the haemolymph of the American cockroach. First, the data clearly indicated that a large increase in hypertrehalosemic hormones occurred in the haemolymph of stressed cockroaches. Secondly, proteolytic activity in the haemolymph of stressed cockroaches was greatly increased. The increase of both hypertrehalosemic hormones and proteolytic activity in the haemolymph appeared to be a non-specific response to different forms of stress, including chemical poisoning with lindane, immobilization, forced movement, starvation, and elevated …

Limbic Mechanisms Controlling Arterial Pressure, Stefanie Roder

Digitized Theses

Three series of experiments were done to investigate the output pathways from the central nucleus of the amygdala (ACe) involved in the control of arterial pressure. The first series of experiments provided the first demonstration that the arterial pressure responses elicited during stimulation of ACe were mediated via a direct pathway to the bed nucleus of the stria terminalis (BST). Microinjection of retrograde tract tracers into depressor regions of BST resulted in labelled neurons within predominantly the lateral subdivision of ACe. In addition, iontophoresis of the anterograde tract tracer PHA-L into cardiovascular responsive regions of ACe resulted in fiber and …

Testing For Mate Choice And Competition In Convict Cichlids Using Ecologically Relevant Contexts, Diane Kathleen Urban

Digitized Theses

Mate choice and intrasexual competition in convict cichlids, Cichlasoma nigrofasciatum, was investigated in the laboratory, during courtship, nest building, guarding eggs, and guarding fry. During courtship, females were expected to use male body size to indicate quality and to compete for large males. Females and newly introduced males were tested under two conditions: Treatment1--the males were similar in body length; and Treatment 2--one male was larger than the other two. No significant difference was found between treatments in the frequency of female proximity to males or in the frequency of female-female aggressive behaviour. However, the large male of Treatment 2 …

Regulation Of Corticosteroid-Binding Globulin Gene Expression, Xian Feng Zhao

Digitized Theses

Corticosteroid-binding globulin (CBG) is a plasma glycoprotein that transports glucocorticoids and progesterone. Strain specific variations were found in rodent CBG coding sequences. Amino acid substitutions at positions 276 and 285 classify CBG of 8 rat inbred strains into 3 groups, and a {dollar}\rm Val\sp{lcub}285{rcub}\to Met{dollar} substitution seems to compensate the detrimental effect of the {dollar}\rm Met\sp{lcub}276{rcub}\to Ile{dollar} substitution on rat CBG steroid-binding affinity. Characterization of a mouse RIIIS/J CBG cDNA identified a single amino acid substitution (Lys{dollar}\sp{lcub}201{rcub}\to{dollar} Glu) that is responsible for the reduced steroid-binding affinity in RIIIS/J CBG. Exogenous glucocorticoids were shown to promote an increase of mouse CBG …

Expression Of Sodium Pump Subunit Genes During Mouse Preimplantation Development, Daniel James Macphee

Digitized Theses

The Na,K-ATPase or sodium pump is an enzyme that is found in most animal cells. The enzyme pumps sodium and potassium ions against their concentration gradients and is hypothesized to be a mediator of fluid accumulation during mouse preimplantation development. The purpose of the present study was to determine, using reverse transcriptase-polymerase chain reaction (RT-PCR), whether all {dollar}\alpha\ (\alpha1,\ \alpha2,\ \alpha3,\ \alpha4{dollar}) and {dollar}\beta\ (\beta1{dollar} and {dollar}\beta{dollar}2) isoforms of the sodium pump were expressed during preimplantation development. Previous work by Watson and Kidder (1988) had shown that the {dollar}\alpha{dollar} subunit was localized to the basolateral domains of mural trophectoderm surrounding …

The Antioxidant Enzymes (Superoxide Dismutase, Catalase And Glutathione Peroxidase): Their Molecular Evolution And Regulation In Mice, Nicholas Joseph Schisler

Digitized Theses

Reactive, oxygen derived free radicals are detoxified by an enzymatic pathway RA-5 which includes the enzymes superoxide dismutase (CuZn and Mn SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). In an effort to understand the molecular evolution and antiquity of these enzymes, comparative techniques were developed for identification and visualization of protein family relationships. Analysis of amino acid sequence data indicated that these enzymes had expected phylogenetic relationships and that the two SOD enzymes were evolutionarily convergent. Multiple sequence alignments of the SOD, CAT and GSH-Px families of proteins were represented quantitatively and used to probe the Swiss-PROT database for proteins …

Comparative Reproductive Ecology Of Female Buffleheads (Bucephala Albeola) And Barrow's Goldeneyes (Bucephala Islandica) In Central British Columbia, Jonathan Edward Thompson

Digitized Theses

Waterfowl (Anseriformes) generally have high energetic costs for reproduction because they lay large, energy-rich eggs. Consequently, many temperate nesting ducks (Anatinae) occupy seasonally productive environments to meet nutritional requirements for egg production. However, ducks in the genus Bucephala often breed in unproductive boreal and montane regions. This study was conducted to investigate nutritional aspects of reproduction in female Buffleheads (Bucephala albeola) and Barrow's Goldeneyes (Bucephala islandica) breeding in central British Columbia.;Diet composition of breeding female Buffleheads and Barrow's Goldeneyes, which consisted primarily of benthic insects, was similar, providing support for the food defense hypothesis as an explanation for evolution of …

Male Reproductive Success And The Mating System Of Bushy-Tailed Woodrats, Michael Graham Topping

Digitized Theses

Bushy-tailed woodrats are nocturnal cricetid rodents distributed throughout the mountainous regions of western North America. Despite a number of studies on the population ecology of this species, little is known about the behaviour of males during the breeding season.;I investigated the reproductive behaviour of male bushy-tailed woodrats in three ways. First, I examined the spatial distribution of individuals within a breeding population, using radiotelemetry and mark-recapture livetrapping. Both males and females exhibited considerable overlap with animals of both sexes, mean intersexual and intrasexual overlap values for each sex did not differ in two of the three years of study. This …

Identification And Characterization Of Thegmha Gene Used For Inner Core Lipopolysaccharide Synthesis In Escherichia Coli, Joanna Susan Brooke

Digitized Theses

Isolation, characterization and definition of the function of the gmhA locus in Escherichia coli could lead to a better understanding of the contribution of lipopolysaccharide (LPS) to bacterial disease. Such a description of the gmhA locus was the objective of the present studies. LPS mutants of Escherichia coli with defects in the biosynthesis and assembly of the heptose component of the core oligosaccharide display a shorter core that compromises the structural integrity of the outer membrane, resulting in a marked inability of these cells to grow in the presence of detergents, bile salts, and hydrophobic antibiotics. A heptoseless lipopolysaccharide E. …

Population Dynamics, Production And Resource Allocation In The Zebra Mussel, Dreissena Polymorpha, From The Lower Great Lakes, Canada, Margo Elizabeth Chase

Digitized Theses

Five populations of Dreissena polymorpha from three lakes (Lake St. Clair, Lake Erie and Lake Ontario) were examined to determine the population dynamics, reproductive cycle, secondary production and the allocation of resources to somatic tissue and shell, and gamete production.;Variation in life history characteristics, such as lifespan, age at first reproduction, maximum size and fecundity were observed both within and among sites, although the among-site variation was greater. The lifespan of D. polymorpha ranged from 2 to {dollar}>{dollar}4 years depending on the lake. The onset of sexual maturity was related to size, not age. Individuals became sexually mature between …

Neurochemical Changes Following Stroke: Role In Neuroprotection And Cardiac Susceptibility, Raymond Tak Cheung

Digitized Theses

The mechanisms mediating neuronal recovery and cardiovascular complications after ischemic stroke are not completely known. In these investigations, I examined changes in neuropeptides and a catecholamine synthesizing enzyme, tyrosine hydroxylase (TH), following middle cerebral artery occlusion (MCAO) in adult male Wistar rats.;Five days following MCAO, the immunoreactivity for TH and neuropeptide Y (NPY) increased in the insular cortex (IC) within the peri-infarct zone. NPY also increased ipsilaterally in the basolateral nucleus of the amygdala, whereas leucine-enkephalin, dynorphin and neurotensin increased ipsilaterally in the central nucleus of the amygdala. Sham MCAO was ineffective.;Neurochemical changes were assessed 5 days after localized excitotoxic …

Seed Colour Variation, Dormancy, And Seed Banks In The Bull Thistle, Cirsium Vulgare (Savi) Ten, Colleen Doucet

Digitized Theses

The bull thistle, Cirsium vulgare (Savi) Ten. is listed as a noxious weed in Ontario and in Australia. It is widespread and found in many disturbed habitats such as roadsides, quarries, construction sites and pastures. Successful weeds are considered to demonstrate, among others, the following features: the production of a large number of small seeds, long-lived seeds, the presence of an efficient dispersal mechanism, and self-compatibility. Although seed production is substantial and Cirsium vulgare is self-compatible, the species has several characteristics that should constrain its demographic success. Seed dispersal is limited and in past studies, this species had been dismissed …

The Central Serotonergic And Cholinergic Systems As Activators Of The Electrocorticogram And Behavior, Hans Christian Dringenberg

Digitized Theses

Experiments were performed on the role of ascending cholinergic and serotonergic electrocortical activating systems and their role in normal physiology and behavior. In urethane-anesthetized rats, electrocortical activation could be obtained by electrical stimulation of the amygdala, the dorsal raphe, the locus coeruleus area, the superior colliculus, and the orbitofrontal cortex. Activation elicited from the amygdala, the locus coeruleus area, and most orbitofrontal sites was abolished by systemic administration of the cholinergic-muscarinic antagonists scopolamine or atropine. Activation elicited from the dorsal raphe or superior colliculus was largely resistant to anti-muscarinic treatment but was abolished by methiothepin, a serotonergic antagonist. Infusions of …

The Effects Of Cholecystokinin On Taste Reactivity In Rats: Evidence In Support Of A Satiety Effect, Lisa Anne Eckel

Digitized Theses

Cholecystokinin (CCK), a polypeptide gut-brain hormone, reduces food intake in a variety of species and across a number of experimental situations. By application of the taste reactivity test, the present thesis examined whether aversive side effects and/or alterations in palatability contribute to the anorectic effects of CCK in rats. Experiment 1 examined the ability of CCK to alter sucrose-elicited taste reactivity responses. Peripheral administration of CCK produced a dose-dependent reduction in ingestive responses without promoting an increase in aversive responses. Experiment 2 examined the ability of CCK to alter taste reactivity responses during oral water infusions. CCK treatment reduced the …

Cold Acclimation: A Complex Interaction Of Low Temperature, Light And The Redox State Of Photosystem Ii, Gordon R. Gray

Digitized Theses

The process of cold acclimation refers to the physiological processes by which cold-tolerant plants such as cereals, when developed at low temperature, acquire freezing tolerance. Photosynthesis provides the energy required for these complex metabolic changes to take place. However, photosynthetic organisms must maintain a balance between energy input as a result of photochemical reactions and energy consumption through intersystem electron transport and the various biochemical reactions of cellular metabolism. Imbalances may be sensed by changes in the redox state of photosystem II (PSII), as this represents the rate-limiting step of photosynthetic electron transport. The redox state of PSII is sensitive …

Parameters Controlling The Initiation Of Replication Of Coronavirus Jhm In Cells Of The Central Nervous System, Kishna Kumar Kalicharran

Digitized Theses

Parameters controlling the initiation of replication of the neurotropic Coranavirus JHMV were investigated to further elucidate the determinants conferring permissiveness or resistance of cells from the central nervous system. Two fines of enquiry pertaining to the early events of JHMV infection were investigated.;One aspect, the mechanism of JHMV penetration into host cells was examined with the fully permissive L-2 fibroblasts as the host. Several inhibitors including phenylarsine oxide, chlorpromazine, trifluoperazine, hypertonic solution and bafilomycin A1 affecting various stages of the endocytic pathway were used to affect penetration. These experimental approaches revealed that most probably JHMV is internalized through receptor-mediated endocytosis …

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 …

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 …

Formation And Fate Of Methyltin Compounds In The Great Bay Estuary (New Hampshire), Anne M. Falke

Doctoral Dissertations

Methyltin compounds (MeSn), which are not of anthropogenic origin, are common in estuaries, particularly in the marsh grass Spartina alterniflora. During the 1989 growing season, S. alterniflora leaves collected from three locations in the Great Bay Estuary were analyzed for MeSn and inorganic tin by hydride generation/atomic absorption spectrophotometry (HG-AAS). Total MeSn concentrations showed a sharp increase early in the season, reaching a maximum on May 23, then gradually decreased. Statistical calculations verified that date was a significant contributor to the observed variance, while location was not.

Two years later the seasonal study was expanded to include below ground portions …

The Effects Of Primary Olfactory Cortical And Thalamic Lesions On Olfactory Continuous Non-Matching To Sample And Discrimination In The Rat, Yueping Zhang

Doctoral Dissertations

Forty-two male rats were pretrained on the olfactory continuous delayed non-matching to sample (CDNMTS) task. They were then matched for performance and randomly assigned to one of the following six treatment groups: excitotoxic lesions of pyriform cortex, later entorhinal cortex, lateral internal medullary lamina (L-IML), mediodorsal nucleus (MDn), nonspecific nuclei, and sham control. After recovery from surgery, the rats were retrained on the olfactory CDNMTS. Delay effects were examined by manipulating retention intervals (RI), with five RIs (4, 6, 9, 13.5, and 20.25 s) randomly mixed within each session. The number of odor stimuli used in each session varied from …

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 …

Variation In Transposable Element Sequence And Activity In The Nematode Caenorhabditis Elegans, Jeremy David Glasner

Doctoral Dissertations

Eukaryotic genomes are replete with transposable elements. The nematode C. elegans will be the first multicellular organism to have its genome completely sequenced. This sequence will allow identification of all the transposon and transposon-related sequences from a single genome. In anticipation of the complete genome sequence I have initiated a series of analyses of sequences from the C. elegans genome database that share significant similarity to known families of transposons. Several members of known transposon families were observed along with a plethora of sequences related to these known transposons. Cladistic analyses were used to describe the relationships among transposons and …