Biology Commons^™

Bone Mineral Density Of The Common Bottlenose Dolphin, Tursiops Truncatus: A Proposed Model For Monitoring Osteological And Ecosystem Health, James Wright Burrus Powell

Dissertations and Theses

Bone mineral density (BMD) in the pectoral flipper of the common bottlenose dolphin, Tursiops truncatus, was examined to address the need to define a comprehensive target site for clinical osteodensitometric assessment and to establish ranges of observed bone density values for this species. Radii were analyzed using dual energy X-ray absorptiometry (DXA), the accepted standard in human medical studies. Multiple loci within the radius were identified and assessed for their correlation to BMD of the entire bone. Radii BMD were also examined for differences based on sex, age, total body length, handedness, geographical affinity, and nutritional status at time …

Fungal Endophytes In A Seed-Free Host: New Species That Demonstrate Unique Community Dynamics, Brett Steven Younginger

Dissertations and Theses

Fungal endophytes are highly diverse, cryptic plant endosymbionts that form asymptomatic infections within host tissue. They represent a large fraction of the millions of undescribed fungal taxa on our planet with some demonstrating mutualistic benefits to their hosts including herbivore and pathogen defense and abiotic stress tolerance. Other endophytes are latent saprotrophs or pathogens, awaiting host plant senescence to begin alternative stages of their life cycles. Most, however, are likely plant commensals with no observable benefits to their hosts while under study. Yet, when considering the context-dependence that may determine plant resistance to pathogen attack, the consortium of endophytes present …

Water Transport In The Lateral Line Canal Of The Intertidal Fish Xiphister Mucosus (Girard 1858) And Its Significance To Evaporative Water With Preliminary Observations Of The Metabolic Consequences Of Water Loss, Whitney Anne Gayer

Dissertations and Theses

The lateral line canal system is a sensory organ found in all teleost fish that has a wide range of morphological variation. Variation in morphology may often be the result of evolutionary necessity where the need for function dictates form. Xiphister mucosus is an amphibious Stichaeid fish that inhabits the rocky intertidal zone of the northeastern Pacific Ocean. The rocky intertidal is considered an extreme environment where crashing waves and ebbing tides may require the specialization of adaptations for surviving the many abiotic stressors encountered there.

The lateral line trunk canal of Xiphister is regarded as unique among teleosts with …

Surviving Catastrophe: Resource Allocation And Plant Interactions Among The Mosses Of Mount St. Helens Volcano, Trevor David Williams

Dissertations and Theses

Mosses are some of the first colonizers to disturbed sites, yet their roles in early plant community structuring are not well understood. The primary succession zones of volcanoes provide opportunities to conduct natural experiments into how mosses contribute to early plant community formation, as well as how the unique environments found in such zones affect plant traits, particularly those associated with stress tolerance. Though plant community changes have been well-documented since Mount St. Helens (MSH) volcano erupted in 1980, the volcano's moss assemblages, their influence on other plants, and their potential roles in chemical-mediated competition and biogeochemical cycling have garnered …

Investigating The Origin And Functions Of A Novel Small Rna In Escherichia Coli, Fenil Rashmin Kacharia

Dissertations and Theses

Non-coding small RNAs (sRNAs) regulate various cellular processes in bacteria. They bind to a chaperone protein Hfq for stability and regulate gene expression by base-pairing with target mRNAs. Although the importance of sRNAs in bacteria has been well established, the mode of origination of novel sRNA genes is still elusive, mainly because the rapid rate of evolution of sRNAs obscures their original sources. To overcome this impediment, we identified a recently formed sRNA (EcsR2) in E. coli, and show that it evolved from a degraded bacteriophage gene. Our analyses also revealed that young sRNAs such as EcsR2 are expressed …

Sex-Specific Fungal Communities Of The Dioicous Moss Ceratodon Purpureus, Mehmet Ali Balkan

Dissertations and Theses

Mosses display a number of hallmark life history traits that influence their ecology at the population and community level. The long lived separation of sexes observed in the haploid gametophyte (dioicy) is one such feature of particular importance, as it is observed in the majority of bryophytes and creates intraspecific specialization of male and female individuals.

The prevalence of sexually dimorphic mosses raises the possibility of sex-specific interactions with fungi as observed in some vascular plants. Here I investigated how moss sex shapes fungal communities associated with gametophytic tissues of the ubiquitous moss, Ceratodon purpureus. Using greenhouse populations of …

Preliminary Characterization Of Mitochondrial Atp-Sensitive Potassium Channel (Mitokatp) Activity In Mouse Heart Mitochondria, Venkat Raghav Aachi

Dissertations and Theses

Myocardial ischemia, infarction, heart failure and arrhythmias are the manifestations of coronary artery disease. Reduction of ischemic damage is a major concern of cardiovascular biology research. As per recent studies, the mitochondrial ATP-sensitive potassium channel (mitoK_ATP) opening is believed to play key role in the physiology of cardioprotection, protection against ischemia-reperfusion injury or apoptosis. However, the structural information of mitoK_ATP is not precisely known. Elucidating the structural integrity and functioning of the mitoK_ATP is therefore a major goal of cardiovascular biology research. The known structure and function of the cell ATP-sensitive potassium channel (cellK_ATP) …

Methionine Metabolism In Fasciola Hepatica, Carol Theresa Ayer

Dissertations and Theses

5'-Deoxy-5'-methylthioadenosine (MTA) is derived from s-adenosylmethionine (AdoMet) during the synthesis of the polyamines spermidine and spermine. Methionine can be regenerated from MTA by one of two mechanisms. In mammalian cells and some microorganisms, MTA is degraded to adenine and 5-methylthioribose-1-phosphate (MTR-1-P) via MTA phosphorylase. In certain other microbes, however, MTA is catabolized in two steps; first to adenine and 5-methylthioribose (MTR) via MTA nucleosidase followed by conversion of MTR to MTR-1-P via MTR kinase.

This study was to demonstrate the presence of MTA nucleosidase or MTA phosphorylase in both redia containing cercariae and adult Fasciola hepatica Linnaeus, 1758. If MTA …

Determination Of Homology Between The Arsenic Resistance Plasmids R45 And R773 In Escherichia Coli, Joshua T. Clark

Dissertations and Theses

The resistance transfer factor R45 from Escherichia coli confers inducible arsenate and arsenite resistance in that bacterium. The genes for these resistances were cloned into the EcoR1 - Sph1 multiple cloning site of PGEM3 Blue vector (Promega) to produce a 4.9 kilobase plasmid, pJC1. This recombinant plasmid, pJC1, conferred IPTG induced resistance to arsenite and arsenate. In addition, pJCl was tested for homology with the E. coli plasmid R773, which encodes for arsenic resistance in that bacterium as well.

Through DNA-DNA hybridization the arsenic resistance determinants of R45 and R773 were compared. Under stringent hybridization conditions, R45 demonstrated DNA sequence …

Aspects Of Cardiovascular Oxygen Transport In Vertebrates, Michael Scott Hedrick

Dissertations and Theses

The hematological and rheological characteristics of blood from a number of vertebrates was compared to assess possible species differences in blood viscosity that may influence cardiovascular oxygen transport. Nucleated red blood cells (RBCs) were more viscous (measured by cone-plate viscometry) in comparison with enucleate (mammalian) RBCs at hematocrits greater than 40% when measured at equivalent temperatures. The lower viscosity of enucleate RBCs is attributed to an enhanced deformability of enucleate cells in comparison to nucleated cells.

Partial Purification And Characterization Of F₄₂₀-Dependent Nadp Reductase From Methanobrevibacter Smithii Strain De1, Scott D. Sheridan

Dissertations and Theses

The F₄₂₀-dependent NADP reductase of Methanobrevibacter smithii has been partially purified employing a combination of affinity chromatography with Blue Sepharose (Cl-6B) and molecular sieve chromatography with Sephacryl S-200, The enzyme, which requires reduced F₄₂₀ as an electron donor, has been purified over 145 fold with a recovery of 6%. A molecular weight of 120,00 for the native enzyme was determined by Sephacryl S-200 chromatography. A subunit molecular weight of 28,200 was determined by SDS-PAGE, indicating that the native enzyme is a tetramer. The optimal temperature for enzymatic activity was found to be 45°C, with a pH optimum …

Serial Cardiovascular Adaptations During Pregnancy, Mark Vincent Hart

Dissertations and Theses

Maternal cardiovascular adaptations appear to be essential in order to supply extra circulation to both the developing fetus and maternal system during a successful pregnancy. Since inadequate cardiovascular adjustments may produce abortions or maternal morbidity, the characterization of maternal cardiovascular changes during pregnancy and the elaboration of the underlying mechanism for these changes are essential to the understanding of how the heart enlarges during pregnancy and what significance this enlargement might have. To provide needed information regarding this time course and extent of maternal cardiac enlargement and the hormonal and hemodynamic changes which may be responsible for these changes, the …

The Absence Of Extrachromosomal Dna In Methanogenic Bacteria, Nancy Ann Kurkinen

Dissertations and Theses

Five species of methanogenic bacteria were analyzed for the presence of plasmid DNA. Several procedures for the detection and isolation of covalently closed circular plasmid DNA were modified for use with the methanogens.

Androgen-Induced Immunosuppression, Debra Ann Weyant

Dissertations and Theses

It is well established that females are more immunocompetent than males as evidenced by higher humoral antibody titers, lowered susceptibility to infection, and more efficient graft rejection.

Furthermore, females also exhibit a much higher incidence of autoimmune disease. These observations have led investigators to believe that the male hormonal environment may play a key role in the regulation of immune response. For this reason, this study is concerned with the expression of autoimmunity and of immune function in the mouse.

This study included the New Zealand Black (NZB) mouse strain, as an animal model for human SLE, as well as …