Digital Commons Network^™

Habitat Ecology Of The Native Subtidal Snail, Lacuna Vincta, In The Gulf Of Maine And The Impact Of Two Introduced Species, Suchana Chavanich

Doctoral Dissertations

Lacuna vincta (Montagu) is a small native herbivorous gastropod that feeds and lives on algae within the rocky subtidal zone of New England. In this study, a combination of field samplings and laboratory experiments were conducted in order to examine the seasonal abundance, feeding preference, and growth of snails on nine different algal species. The results showed that there were differences in the seasonal abundance patterns of L. vincta populations on different algal species. However, the snail populations in all size classes were found year round on Laminaria saccharina (L.) Lamour. Feeding preference experiments showed that L. vincta preferred Antithamnionella …

The Enzymatic Function Of The Ccr4 Protein, Junji Chen

Doctoral Dissertations

The CCR4-NOT complex from Saccharomyces cerevisiae, which exists in two forms in vivo: 1.9 and 1.0 x 10 6 MDa in size, is a general transcriptional regulatory complex. It regulates mRNA transcription in initiation, elongation and degradation.

The 1.0 MDa complex was purified to near homogeneity, and mass spectrometric analysis was used to identify all the components of the complex. The 1.0 MDa complex contains CCR4, CAF1, NOT1--5, and two new proteins, CAF40 and CAF130. CAF130 and CAF40 are two unique yeast proteins, with CAF40 displaying extensive homology to proteins from other eukaryotes. Immunoprecipitation and gel filtration experiments confirm that …

Identification Of Suppressors Of Spt10 That Affect Adh2 Expression In The Yeast Saccharomyces Cerevisiae, Bradley David Anderson

Doctoral Dissertations

Suppression of the effects of an spt10 mutation on ADH2 expression is a phenotype shared by a small number of genes involved in the regulation of gene expression. All six known suppressors of spt10 are either components of the CCR4-NOT Complex (CCR4, CAF1, NOT4), or have been shown to interact with the complex ( DBF2, SRB9, SRB10). This indicated that spt10 suppression may be characteristic of CCR4-like gene regulation. In this work, I conducted a screen for additional suppressors of spt10 at ADH2. The screen identified no less than ten complementation groups, including ADH2 and two known suppressors of spt10, …

Using Satellite Remote Sensing To Model And Map The Distribution Of Bicknell's Thrush (Catharus Bicknelli) In The White Mountains Of New Hampshire, Stephen Roy Hale

Doctoral Dissertations

Landsat-7 Enhanced Thematic Mapper satellite imagery was used to model Bicknell's Thrush (Catharus bicknelli) distribution in the White Mountains of New Hampshire. The proof-of-concept was established for using satellite imagery in species-habitat modeling, where for the first time imagery spectral features were used to estimate a species-habitat model variable. The model predicted rising probabilities of thrush presence with decreasing dominant vegetation height, increasing elevation, and decreasing distance to nearest Fir Sapling cover type. To solve the model at all locations required regressor estimates at every pixel, which were not available for the dominant vegetation height and elevation variables. Topographically normalized …

Ecological Impacts Of Shrimp Trawling On Juveniles Of Selected Benthic Fish Species In The Southwestern Gulf Of Maine, Augustine Japieni Mungkaje

Doctoral Dissertations

The ecological impacts of shrimp trawling on juveniles of selected benthic fish were studied in the southwestern Gulf of Maine. The fish community and selected environmental variables were sampled at two sites in summer and winter during 1998 and 1999. The community was composed of 24 species in 12 families. Site 1 was dominated by longhorn sculpin, Myoxocephalus octodecemspinosus , while American plaice, Hippoglossoides platessoides, was the dominant species in Site 2. Red hake, Urophycis chuss was abundant at both sites. There were also seasonal differences in the flux of fish at the two sites.

Correlation analysis showed the abundance …

The Effect Of Freeze /Thaw Temperature Fluctuations On Microbial Metabolism Of Petroleum Hydrocarbon Contaminated Antarctic Soil, Conrad George Leszkiewicz

Doctoral Dissertations

Petroleum contaminated soil exists at McMurdo Station in Antarctica. These soils were contaminated with historic releases of JP-8 jet fuel. Over time, there does not appear to have been significant reduction in the petroleum concentrations in these soils. This lack of reduction has been attributed to the extremely cold Antarctic environment and the lack of available moisture.

Cold temperatures and/or lack of moisture may not be the factors inhibiting biodegradation. Soil temperatures can exceed 20 degrees centigrade (°C) during the austral summer and melt water becomes available. However, the soil temperatures have also been reported to fluctuate rapidly. Swings of …

The Ecological, Behavioral, And Genetic Factors Influencing The Diversification Of Lake Malawi's Rock -Dwelling Cichlids, Patrick D. Danley

Doctoral Dissertations

Rapid evolutionary radiations provide insight into the fundamental processes involved in species formation. Here I examine the diversification of one such group, the rock-dwelling cichlid fishes of Lake Malawi (mbuna), which have radiated from a single ancestor into more than 200 species over the past 700,000 years. Through the examination of several molecular phylogenies, a phylogenetic history of the mbuna is proposed. The diversification of this group has proceeded in three major bursts of cladogenesis each of which has been dominated by a single selective force (selection on habitat preferences, trophic morphology, and male nuptial coloration, respectively). A divergence with …

The Physiological Role And Characterization Of Melanin Produced By Shewanella Algae Bry, Charles Edwin Turick

Doctoral Dissertations

Shewanella algae BrY is a Gram negative, facultative anaerobe isolated from the Great Bay Estuary of New Hampshire. This member of the gamma Proteobacteria demonstrates extensive versatility in the variety of terminal electron acceptors it uses for anaerobic respiration. Since the natural habitat of this non-fermenting organism is the oxiclanoxic interface of sediments, the ability to utilize various terminal electron acceptors contributes to its survival and growth. Among the terminal electron acceptors used by S. algae BrY are insoluble iron minerals. The transfer of electrons from a bacterial cell to an insoluble compound presents a strategic challenge for this organism. …

Relational Learning For A Sustainable Future: An Eco -Spiritual Model, Mary Elizabeth Westfall

Doctoral Dissertations

We are facing unprecedented environmental challenges as we enter the new millennium as human choices and practices have repeatedly led to environmental degradation. Increasingly there are individuals and groups seeking to address this environmental crisis and move toward more sustainable patterns of living. But in order to make alternative choices it will be essential to draw upon the wealth and variety of human capabilities.

For nearly 350 years Western culture has looked to reason and rationality to provide truth and direction. The affective side of being human, feelings, intuition, love, care, wonder, mystery and hope have largely been devalued. In …

Detection Of Giardia Lamblia And Cryptosporidium Parvum In The Eastern Oyster (Crassostrea Virginica) Harvested From The Great Bay Estuary, Kim Marie Stowell

Doctoral Dissertations

The Great Bay Estuarine system is being impacted by point source and nonpoint source pollution that affect shellfish quality. Many outbreaks of human gastroenteritis are potentially caused by the consumption of raw or undercooked oysters in which the protozoan pathogens, Giardia lamblia and Cryptosporidium parvum are present. The development of a rapid and sensitive technique to detect infectious protozoa in oysters is a necessity.

Immunofluorescence has been employed as a technique for the detection of these organisms in drinking water. Cross reactivity with algae and the production of false positive results limits the usefulness of this technique in environmental studies. …

The Relationship Between Fruit Color Traits And Anthocyanin Genes In Diploid Fragaria, Chaoyang Deng

Doctoral Dissertations

A candidate gene approach was used to determine the likely molecular identity of the c locus (yellow fruit color) in Fragaria vesca, a diploid (2n = 2x = 14) strawberry. Using PCR with degenerate primer pairs, intron-containing segments of structural genes coding for the enzymes: chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanindin synthase (ANS), and one Del-like regulatory gene (RAN) in the anthocyanin biosynthetic pathway were amplified, cloned and sequenced. Intron length polymorphisms for each of these genes were detected among three diploid varieties: F. vesca Alpine variety 'Yellow Wonder' (YW) (Europe); DNIC, an …

Regulation Of Mammalian Photoreceptor Phosphodiesterase (Pde) By Its Noncatalytic Gaf Domains And Its Two Small Subunits, Gamma And Delta, Hongmei Mou

Doctoral Dissertations

cGMP phosphodiesterase (PDE) is the central effector of visual transduction in retinal rod photoreceptors. The overall goal of this work was to investigate the possible regulatory mechanisms of PDE in mammalian rod photoreceptors by its noncatalytic cGMP binding sites on the PDE catalytic dimer (Palphabeta), and by the interactions between the inhibitory Pgamma subunit and Palphabeta in their phosphorylated and non-phosphorylated states.

First, the binding of cGMP to the noncatalytic sites on membrane-associated PDE (PDE-M) and soluble PDE (PDE-S) was characterized. We found that PDE-M holoenzyme contains 2 non-identical high-affinity cGMP binding sites; one of the cGMP binding sites is …