Digital Commons Network^™

Community And Ecosystem Analysis Of Forests Recovering From Landslide Disturbance: White Mountain National Forest, New Hampshire, David M. Bryant

Doctoral Dissertations

Sites recovering from landslide disturbance offer many opportunities to study ecosystem processes under extreme conditions. Landslides reset the topographic, microclimatic, parent material and vegetation state factors of ecosystem development. Water, and nutrient resources following landslides are more heterogenously distributed. Soil structure and development is disrupted. Solar insolation and diurnal temperature fluctuation exceed that of the surrounding forest. Consequently, plant colonization and community succession differ from less severely disturbed sites such as timber harvest or agricultural afforestation.

Two chapters of this dissertation address the unique conditions of landslide ecosystem development. Chapter 2 compares historical data collected in 1956 on a chronosequence …

Photoprotective Role Of Beta -Carotene And Antioxidant Enzymes: A Shield Against Ultraviolet Damage In Dunaliella Bardawil, Andrea Lynn Grossman-White

Doctoral Dissertations

Photosynthetic and antioxidant responses following exposure to an array of irradiances and frequencies were examined and contrasted in two species of the unicellular green alga Dunaliella. Species selection was based on the ability of Dunaliella bardawil (UTEX 2538) to accumulate massive quantities of inter-thylakoid beta-carotene during exposure to stress or high irradiances of photosynthetically active radiation (PAR: 400-700 nm) while Dunaliella salina (UTEX 200) lacks this ability. Cells were cultured in two irradiances (150 and 35 mumol photons ·m-2·s -1), and then exposed to high red (wavelengths > 590 nm) or blue light (390-540 nm; 150 mumol photons·m -2·s--1), ultraviolet-A (320-400 …

A Test Of The Ideal Free Distribution In Panhandling Humans, Leann Louise Milinder

Doctoral Dissertations

The Ideal Free Distribution (Fretwell and Lucas, 1970), an optimization model from behavioral ecology, predicts that a group of animals will distribute themselves across habitats with unequal resources such that all animals have equal success rates. The six experiments of this dissertation demonstrated that humans conform to the IFD with about the same sensitivity as animals and respond similarly when assumptions of the model are violated. The present study also revealed that cooperation, and its effect on the functional size of the foraging unit, may be an important factor in understanding the distribution of social foragers.

Experiments 1 and 2 …

Influences Of Social And Habitat Features On Selection And Use Of Breeding Habitat And Pup Survival In South American Fur Seals, Monica Anne Stevens

Doctoral Dissertations

Quantitative information is lacking about how fur seals use habitat and how this use influences fitness. Such information is important for understanding the prospects for recovery of declining populations like those of South American fur seals (Arctocephalus australis) in Peru. In this study I examined the influences of habitat features and human disturbance on selection of breeding habitat by female fur seals in Peru; and I examined how mortality of pups was influenced by habitat features, female behavior, and the social environment on the beach.

Arctocephalus australis in Peru have declined gradually over the past decade, and declined dramatically (72%) …

Birth, Death And Taxis: North Atlantic Right Whales In The Twenty-First Century, Scott Douglas Kraus

Doctoral Dissertations

Twenty two years of North Atlantic right whale data were analyzed. Several measures indicate reproduction in North Atlantic right whales is in a decline. Calving intervals have increased from about 3.3 years in the 1980's to over 5 years, and the age of first parturition is estimated to be 11 years. Females may lose calves before they are detected, artificially increasing the apparent age of first parturition and possibly affecting estimates of calving interval. Northern feeding habitat use patterns do not appear to affect reproduction.

Right whale mortality data was analyzed by age, sex, and habitat use patterns. A total …

Expression, Activation, And Regulation Of Matrix Metalloproteinase 2 (Mmp-2) In The Bovine Corpus Luteum, Bo Zhang

Doctoral Dissertations

Matrix metalloproteinases (MMPs) have been postulated to be important for angiogenesis and for tissue remodeling events associated with corpus luteum (CL) development. The MMPs are mainly regulated at three levels, transcription, activation, and inhibition by endogenous tissue inhibitors of metalloproteinases (TIMPs). Unlike most MMPs, pro-MMP-2 activation is accomplished on the cell surface rather than extracellularly. The objectives of the present study were to clone bovine cDNAs for MMP-2 and its activator, membrane type 1- (MT 1-)MMP, to investigate the expression and localization of MMP-2, MT1-MMP, TIMP-1, and TIMP-2 in three ages of CL, and to explore the regulation of MMP-2 …

Regulation Of Ethylene Receptor Expression In Arabidopsis, Xue-Chu Zhao

Doctoral Dissertations

The ethylene receptor family of Arabidopsis consists of five members, ETR1, ETR2, ERS1, ERS2, and EIN4. Regulation of ethylene receptor expression in Arabidopsis was studied using three different approaches. First, the effect of ethylene-pathway mutations upon expression of ETR1 was examined. Ethylene-insensitive mutations in ETR1 resulted in a post-transcriptional increase in levels of the mutant receptor. Treatment of seedlings with silver, which leads to ethylene insensitivity, also resulted in an increase in levels of ETR1. Mutations in other components of the ethylene pathway had little effect upon expression of ETR1. Second, microarray analysis was performed using reciprocal mutants to examine …

Genetic Basis Of Adaptive Radiation In East African Cichlids, Richard Craig Albertson

Doctoral Dissertations

East African cichlids are a paramount example of adaptive morphological radiation. The most dramatic difference among species occurs in oral jaw design and correlates with ecological niche partitioning. Convergent evolution of trophic forms between lakes suggests a common mechanism. What combination of intrinsic and extrinsic factors constitute this mechanism still remains to be seen. The goal of this dissertation was to examine the genetic basis of shape differences between two closely related cichlid species that employ alternate modes of feeding. This was achieved through a number of independent experiments. First, I used field data to characterize the way in which …

The Effects Of Erythrocyte Alloantigen L On The Avian Immune Response, Zdravka Ognyanova Medarova

Doctoral Dissertations

Experiment 1 examined the alloantigen system L effects on Rous sarcomas in three B complex genotypes. The parental stock were 50% Modified Wisconsin Line 3 and 50% inbred Line 6.15- 5. B2B5 L1L2 x B2B5 L 1L2 matings produced experimental chicks. Chicks were inoculated with 20 pock-forming units (pfu) Rous sarcoma virus (RSV) at 6 weeks-of-age. Tumors were scored six times over 10 weeks postinoculation. Tumor scores were used to assign a tumor profile index (TPI) to each chicken. Results were evaluated by ANOVA. The B complex affected the responses. Separate analyses revealed L system effects ( P < 0.05) only in B5B 5 chickens.

Experiment 2 …

Evolution Of Gender Associated Mitochondrial Dna In Bivalves, Jason Paul Curole

Doctoral Dissertations

Bivalves of the families Unionidae and Mytilidae possess a unique mode of mitochondrial DNA inheritance dubbed sex-limited mitochondrial DNA (mtDNA) inheritance or doubly-uniparental inheritance (DUI). In contrast to the matrilineally restricted inheritance of mtDNA in other metazoans, these bivalves have both matrilineally and patrilineally inherited mtDNA lineages. Although the matrilineally inherited mtDNA (or F type) is present in the somatic tissues of both sexes and the female gonad, the patrilineally inherited mtDNA (or M type) is limited to the male gonad. In Mytilus several observations have been made concerning the evolution of DUI. Firstly, the fidelity of DUI is not …

Life History Dynamics Of Nudibranch Sibling Species In The Genus Dendronotus In The Gulf Of Maine, Chad Gordon Sisson

Doctoral Dissertations

Two different larval types have been described for the nudibranch Dendronotus frondosus (Ascanius, 1774) in the Gulf of Maine. A taxonomic review of adults with planktrophic larvae and those with lecithotrophic larvae revealed regular differences in radula morphology, and no predictable differences in the reproductive system. These data and previous data on a behavioral reproductive isolation mechanism suggest a new species designation for populations of Dendronotus with lecithotrophic larvae. Laboratory studies were used to compare the larval dispersal potential of the two types of Dendronotus. D. frondosus planktotrophic larvae had a potential planktonic period of approximately 11 weeks at 10°C …

Impacts Of The Introduced Crabs, Carcinus Maenas And Hemigrapsus Sanguineus, In Northern New England, Megan Conlon Tyrrell

Doctoral Dissertations

Two introduced crab species are presently found in northern New England, Carcinus maenas, which has been in this region for over 100 years, and Hemigrapsus sanguineus which was first reported in New Hampshire in 1998. Carcinus maenas is a generalized predator and its introduction has had negative effects on several native mollusc species but the community wide impacts of its introduction have been relatively neglected. Hemigrapsus sanguineus is just beginning to establish populations in this region, and its effects on the resident community are unknown. Both monitoring and experimental approaches were used to retroactively infer the impacts of C. maenas …

Assessing Ice Storm Damage To Hardwood Forest Canopies Using The Advanced Solid-State Array Spectroradiometer (Asas) And Landsat Tm Imagery, James Stuart Burnett

Doctoral Dissertations

A major ice storm in January 1998 damaged 17 million acres of forestland in the Northeastern United States and Quebec Province. In July 1998 the airborne multiangle hyperspectral sensor, Advanced Solid-State Array Spectroradiometer (ASAS), acquired imagery for nine ice damaged target areas in the White Mountain National Forest (WMNF). Ice damage was also measured in situ at 288 sample plots. Radiance values for nadir ASAS images were normalized and the blue shift of the red edge was represented as the radiance value at 714 nm (714nr). The 714nr for 210 sites in 3 damage classes differentiated severely damaged sites from …

Ompd But Not Ompc Is Involved In Adherence Of Salmonella Enterica Serovar Typhimurium To Human Cells, Bochiwe Hlezipi Hara-Kaonga

Doctoral Dissertations

Salmonella enterica serovar Typhimurium expresses three major outer membrane proteins: OmpC, OmpF, and OmpD. Conflicting reports exist regarding the role of OmpC and OmpD in the pathogenesis of this organism. This study investigated the role of OmpC and OmpD in adherence to human U937 macrophages and T84 intestinal epithelial cells. OmpC and ompD mutant strains were created by transposon mutagenesis utilizing P22-mediated transduction of Tn10 and Tn 5 insertions into wild-type strain 14028. Fluorescein-labeled wild-type and mutant bacteria were incubated with PKH26-labeled T84 cells at various bacteria-to-cell ratios for 1 h at 37 C. Single and dual fluorescence of samples …

Comparative Anatomy And Evolution Of The Gastrotrich Muscular System, Richard Hochberg

Doctoral Dissertations

Gastrotrichs figure prominently in metazoan phylogeny because they share a suite of complex morphological characteristics with several other members of the Bilateria. But their microscopic size, cryptic interstitial habitat, and lack of fossil record have exacerbated the usual barriers to phylogenetic analysis. To arrive at a better understanding of gastrotrich systematics and evolution, cladistic analyses and detailed studies of the muscular system were performed.

A fluorescent F-actin stain was applied to whole mounts of 26 species of Gastrotricha to characterize the musculature. Muscle patterns were mapped, their functions inferred, and the direction of evolution hypothesized for several families. The musculature …

Transgenic Manipulation Of Polyamine Metabolism In Poplar, Pratiksha Bhatnagar

Doctoral Dissertations

Polyamines are low molecular weight polycations found in all living organisms. They are involved in plant stress response and development. The study was aimed at analyzing the effects of altered polyamine metabolism on the polyamine and related pathways in transformed poplar cells overexpressing a mouse odc cDNA under the control of 2X 35S CaMV promoter. The transgenic cells (line 2E) showed elevated levels of mouse ornithine decarboxylase enzyme activity, several fold higher amounts of putrescine, a small increase in spermidine, and a small reduction in spermine as compared with non-transgenic (NT) cells. The conversion of labeled ornithine into putrescine was …