Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 287-338).

Giant cane [Arundinaria gigantea (Walter) Muhl.] is a native bamboo species that was once widely distributed within bottomland forests and as extensive monotypic stands (canebrakes) along waterways of the southeastern United States. Land conversion to agriculture greatly decreased the distribution of canebrakes. Limited to less than two percent of its historic range, canebrakes are now considered an endangered ecosystem. A 0.24 hectare low maintenance experimental nursery of giant cane was established at Southern Illinois University to examine the effect of planting stock type, soil amendments, and four collection sources on cane survival and growth (number of culms, height and diameter of the tallest culm, spread between furthest two culms) after two growing seasons. All treatments, plus interactions of source by soil, and source by stock, were significantly affected by survival. Collection source significantly affected all growth measurements. Stock type affected the number of culms, height, and spread. Soil amendments did not significantly influence any growth measurement but affected soil chemical properties. The interactions between source and stock affected the number of culms, height, and spread. The interaction between stock and soil significantly affected spread, but no other interactions significantly affected any growth measurements. Of all treatment combinations, the Cypress Creek West source, when grown in containers, tended to have the greatest survival and overall growth after two years, regardless of soil amendments. This study highlights factors that are important in establishing a giant cane restoration nursery. This nursery will also generate growing stock for future canebrake restoration and rehabilitation projects.

xii, 148 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / The gumboot chiton Cryptochiton stelleri is the largest intertidal invertebrate herbivore on rocky shores in the Pacific Northwest. This study documented the larval development, metamorphosis, distribution and life history of this species. Growth rings in valves of Cryptochiton stelleri and Katharina tunicata were used to determine age and showed life spans of at least 40 years for C. stelleri and 17 years for K. tunicata. Field surveys in southern Oregon showed that C. stelleri populations are densest in small coves as a result of mortality, food availability, or larval retention. Growth curves based on length, weight and volume were created for several intertidal invertebrates. When incorporated into energy allocation models, length-based curves can underestimate growth and exaggerate an energetic shift from growth to reproduction. Estimates of food intake and reproductive output showed that continuous growth leads to higher food intake and increased fecundity in several organisms with indeterminate growth. / Committee in Charge: Dr. Alan L. Shanks, Chair; Dr. Cynthia D. Trowbridge; Dr. Richard B. Emlet

No description available.

Les bénitiers font partie des espèces protégées, mais l’espèce Tridacna maxima reste encore très présente en Polynésie française. L’étude de sa structure génétique a permis de caractériser pour la première fois une lignée monophylétique de bénitiers en Polynésie Française, composée de deux clades distincts répartis de part et d’autre d’un axe nord-ouest/sud-est séparant majoritairement les populations des Tuamotu (mapiko nord) de celles des autres archipels (mapiko sud). La connectivité entre les populations des différentes îles n’est pas cohérente avec les courants océaniques de surface actuels en Polynésie française. Ces résultats, et ceux obtenus sur des bénitiers provenant de Fidji et de Tonga, ont permis d’émettre des hypothèses sur la colonisation de la Polynésie française par les bénitiers et les facteurs qui ont influencé la connectivité actuelle. Présentant une plus faible diversité génétique que les populations de T. maxima de la région Indo-Pacifique, celles de Polynésie française pourraient être plus vulnérables aux changements environnementaux. La capacité d’adaptation au stress des bénitiers a été étudiée par une étude intégrée des variations de la composition en métabolites et de l’expression génique lors d’expériences de réchauffement. La composition en acides gras des bénitiers a notamment été établie pour la première fois lors de nos travaux, et sa variation évaluée au cours du stress. Les données de transcriptomiques ont pour la première fois mise à jour les voies de réponses au stress thermique chez les bénitiers dont certaines semblent corrélées aux variations observées de la composition en acide gras. L’effet de la proximité des bénitiers avec les coraux dans le milieu et l’impact d’un second type de stress supplémentaire ont également été évalués. L’étude des Symbiodinium des bénitiers a permis de montrer que leur résistance et leur capacité d’adaptation au stress d’une durée de 15 jours seraient indépendantes des communautés symbiotiques. Mots clé : Tridacna maxima, bénitier, Polynésie française, diversité génétique, stress thermique, étude intégrée, transcriptomique, métabolomique, Symbiodinium. / Giant clams are endangered species but Tridacna maxima is still well represented in French Polynesia. Firstly, the genetic structure assessment has led to the discovery of a monophyletic group composed of two new T. maxima clades in French Polynesia which cohabite over a large area with a North-West South-East axis on either side of which, one of each clade is dominant: “North Mapiko” (Tuamotu group) and “South Mapiko” (other archipelagos group). Interconnectivity between different island giant clam populations is not consistent with the present flow of oceanic currents. These results, along with those obtained for Tongian and Fidjian samples, allowed us to suggest hypothesis regarding the giant clam colonization of French Polynesia and the factors which may have influenced the present connectivity. French Polynesian T. maxima was found to have a lower genetic diversity compared to those from Indo-Pacific region, and so considered to be relatively more vulnerable to environmental global changes. Stress adaptation capacity of giant clam was assessed by the follow-up of the metabolite composition and gene expression variations during a thermal time course experiment. Giant clam fatty acid composition was established for the first time and its variation was evaluated along the stress experiment. Impact of the thermal stress on the metabolite composition and gene expression were disclosed. Variation in fatty acids compositions was observed and linked to variation in some specific gene expression. Impact of giant clam proximity with corals and impact of a second supplementary applied stress were also assessed. Study of Symbiodinium symbiosis with giant clam showed that giant clam resistance and adaptation capacity observed for 15 days was independent of symbiotic community behavior. Key words : Tridacna maxima, giant clam, French Polynesia, genetic diversity, thermal stress, integrative approach, transcriptomic, metabolomic, Symbiodinium.

Tesis par optar al grado de Magíster en Ciencias de la Ingeniería, Mención Química / Memoria para optar al título de Ingeniera Civil en Biotecnología / El aumento del consumo energético y la escasez de recursos de origen fósil, han impulsado proyectos de generación de biocombustibles de tercera y cuarta generación como el de producción de etanol a partir del alga chilena M. pyrifera mediante la bacteria E. coli BAL1611. En este estudio, se obtuvo rendimientos de producto y biomasa menores que los reportados con el alga original S. japonica. Hipotéticamente, habría un desbalance redox interno en la bacteria por lo que, para mejorar la producción de etanol, se decide estudiar in silico cómo afectan las fuentes de carbono en la distribución de flujos y concentración de metabolitos, y así proponer circuitos genéticos o metabólicos que regulen el sistema. Además, se decide proponer nuevos productos de interés comercial que se pueden generar desde M. pyrifera mediante E. coli BAL1611. Las simulaciones del modelo cinético construido para E. coli BAL1611 muestran que existe escasez de poder reductor intracelular, aunque la causa de la menor producción de etanol se debe a la saturación de la enzima KDG-6-fosfato aldolasa (EDA) de la ruta de Entner-Doudoroff. Los estudios para optimizar la producción de etanol a partir de M. pyrifera indican que la sobreexpresión de EDA y alcetaldehido deshidrogenasa (ALDH), junto con el knock-out de malato-quinona oxidorreductasa (MQO), es la combinación de mutaciones que genera el mayor rendimiento de producto/sustrato, correspondiente a 0,29, aproximadamente el doble que para el caso de la E. coli BAL1611 sin mutaciones. Por otra parte, analizando otros productos de interés como ácido láctico y succínico queda de manifiesto que, utilizando Macrocystis pyrifera como sustrato, E. coli BAL1611 es una inadecuada alternativa para generar ácido láctico debido a los bajos rendimientos alcanzados. En cuanto a ácido succínico, se propone como combinación de mutaciones la sobreexpresión de la enzima EDA y el transporte de succinato, junto con el knock-out de succinato deshidrogenasa (SDH) y ALDH, obteniendo un rendimiento de 2,37, cinco órdenes de magnitud mayor al caso de la E. coli BAL1611 original. Además, se observa una relación inversa entre el crecimiento y la producción para etanol y ácido succínico. Finalmente, se propone implementar las mutaciones respectivas para cada producto en un circuito genético que regule la producción mediante quorum sensing, disociando el crecimiento de la producción. Además, se sugiere realizar mejoras en el planteamiento de algunas ecuaciones del modelo, para luego construir una plataforma que permita determinar todos los bioproductos de interés comercial que puedan ser generados de forma eficaz a partir de Macrocystis pyrifera mediante la E. coli BAL1611.

Preservation of giant pandas, Ailuropoda melanoleuca, is a worldwide concern. This study was designed to examine dietary and reproductive challenges associated with panda management. Phytoestrogens are natural plant compounds that mimic estrogen and often negatively impact mammalian reproduction. Phytoestrogens in bamboo, the panda’s primary food source, is unknown. Here, estrogen radioimmuno- and receptor-binding assays revealed estrogenic activity in three species of Phyllostachys bamboo. These results present indirect evidence of phytoestrogenic mimics in bamboo, but their relevance is still unknown. Studies were also conducted to observe panda reproductive behaviors in an attempt to augment the use of an artificial vagina (AV) for semen collection. A preliminary study confirmed the panda could differentiate between estrus urine and a water ‘control.’ However, when estrus urine was placed on the AV as an attractant, the subject didn’t approach the AV. Further investigation of dietary challenges and reproductive alternatives are needed to substantiate these findings.

No description available.

A thorough understanding of nucleosynthesis and element formation in stars of all evolutionary phases is of vital importance in stellar astrophysics. It provides information about internal structure, conditions and nuclear processes occurring in the stellar interior. The heavy elements formed in a star throughout its life are returned to the interstellar medium through mass loss processes. New populations of stars are then formed from this previously enriched material. This continues the cycle of element recycling in the Universe and has great consequence for galactic chemical evolution. As both modelling and observing techniques advance, more surveys are required to ensure there is agreement between the two. It is hoped that when a thorough understanding of the internal processes in giant stars is reached, the evolutionary models will reproduce the observed elemental yields. This work provides an internally self-consistent analysis of the element abundances produced via nucleosynthesis and s-process element formation occurring in giant stars in different stellar environments. High resolution spectroscopic observations have been taken of Asymptotic Giant Branch (AGB) and Red Giant Branch (RGB) stars in three different stellar environments. Spectrum synthesis has been used to determine s-process element abundances for RGB stars in the Hyades open cluster, RGB and AGB stars in the globular cluster, 47 Tucanae, and AGB stars in the galactic field. It was found that the two Hyades giant studied showed solar, or near-solar, abundances of s-process elements. Enhancements in the light s-process elements, Y and Zr, of +0.02 to +0.11 were observed, while enhancements in the heavy s-process elements, La, Pr and Nd, ranged from +0.06 to +0.16. These results are consistent with previous findings of enhancements in Y of ~+0.12, and of ~+0.15 for the heavy s-process elements. The results from 47 Tucanae suggest a genuine star-to-star scatter in the s-process element abundances in the giant stars of this globular cluster. This is unexpected due to the fact that stars in a globular cluster are thought to have the same formation and chemical history. However, spreads in s-process element abundances of as much as +-0.7 dex are observed between this study and three other studies of similar stars in the same cluster. A range of field stars along the AGB phase, ranging from M to MS to S to SC, have been analysed for s-process enrichment. The observed element abundances are compared with those predicted by recent modelling of the AGB phase of evolution. Enhancements in s-process element abundances range from [s/Fe]~0.00 for M stars, to ~+0.50 for MS stars, through to ~+0.95 for S stars. The comparison of these enhancements with those predicted by modelling provides an indication of the success of these models and will enable theoreticians to further refine their understanding of the internal nucleosynthetic processes present in giant stars.

No description available.