Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 77-78). Also available on the World Wide Web.

A comparative study was conducted on the growth of Dunaliella tertiolecta using defined inorganic medium and swine waste-seawater medium as sources of nutrients. The nitrogen concentration was maintained at ca 1200 ± 5° ug~at N 1⁻¹ for both media. There were no significant differences in the daily measurements of cell densities and dry weights of D. tertiolecta grown in defined inorganic medium and swine waste-seawater medium in either hatch or continuous culture systems. The algal biomass produced from continuous culture system was used as food for the brine shrimp, Artemia salina L. The brine shrimp fed with D. tertiolecta grown in swine waste-seawater medium and those fed with _D. tertiolecta cultured in defined inorganic medium showed no significant differences in their daily total length and percentage survival measurements. A 57-58% Artemia biomass conversion efficiency was calculated. Statistical analysis for biomass conversion efficiency showed no significant differences for Artemia fed with D. tertiolecta grown in swine waste-seawater medium and that fed with D. tertiolecta cultured in defined inorganic medium. / Land and Food Systems, Faculty of / Graduate

El valor de Artemia como insumo alimenticio de diferentes especies marinas, se ha incrementado exponencialmente y en la actualidad constituye no solo el mejor sino el único alimento vivo válido para muchas especies acuáticas en sus primeros estadios larvarios, debido a su composición de ácidos grasos poliinsaturados (HUFA w3). El objetivo del presente trabajo fue determinar la factibilidad del uso de insumos alimenticios disponibles en el mercado local, que sean económicamente rentables para la obtención de biomasa de Artemia franciscana, cepa Virrilá,Perú. / --- The value of Artemia as nutritious input for different marine species has been increased exponentially and at the present time it constitutes not just the best but the only living food valid for many aquatic species in their first larval stages, due to its long chain fatty acid composition, specially HUFA w3. The objective of the present study was to determine the feasibility of using nutritious inputs available in the local market that are economically profitable for obtaining biomass of Artemia franciscana from Virrilá, Perú. For that reason a semiintensive culture was carried out in the Marine Culture Laboratory , Peruvian Marine Research Institute of Peru, Callao, since may 1998 to jun 1999, using different diets based on “flours” and marine microalgae.

No description available.

Graduation date: 1994

El presente trabajo se centra en el estudio comparativo de distintos aspectos de la respuesta frente a la exposición tóxica de cadmio de diferentes poblaciones de Artemia pertenecientes a las especies Artemia parthenogenetica, Artemia salina, Artemia franciscana y Artemia persimilis. La primera parte de este estudio, pone de manifiesto la variabilidad fenotípica de la respuesta letal a la exposición a cadmio que presentan los nauplios. En este sentido, la utilización de Modelos Lineales Generalizados ha sido de gran utilidad ya que ha permitido poner de manifiesto, a través de los parámetros que definen cada curva de mortalidad, diferencias en sensibilidad al tóxico y en la uniformidad de respuesta entre las distintas poblaciones de Artemia estudiadas. Además ha permitido conocer la influencia de factores genéticos (especie, nivel de ploidía), ambientales (población) así como el modo de reproducción (bisexual y partenogenética) en la sensibilidad al cadmio, destacando entre las demás poblaciones la alta tolerancia de las poblaciones pertenecientes a A. persimilis (A) y A. parthenogenetica (de la laguna de Pétrola) (P). La segunda parte, aborda el estudio comparado del proceso de acumulación de cadmio en individuos adultos de las diferentes poblaciones. Estos procesos han sido cuantificados aplicando un modelo toxicocinético con cinética de primer orden basado en un sistema de dos compartimentos, con el que se han conseguido ajustes relativamente buenos, teniendo en cuenta la complejidad de los procesos implicados. Hemos encontrado un comportamiento cadmio-regulador en Artemia, una eliminación relativamente rápida del metal, y un patrón de acumulación de cadmio bastante conservado en el género, siendo A. persimilis la única población que presenta un modelo diferente a las demás, caracterizado por una menor constante de acumulación y factor de bioconcentración (BCF). Por último en la tercera parte se analizó la presencia de metalotioneína (MT) en individuos adultos de Artemia y su incremento ante la exposición a cadmio, estudiando la influencia de la población y el sexo. Los mayores niveles de MT basal se encontraron en hembras de A. persimilis, que junto con las hembras de A. franciscana procedentes de San Francisco (SF) alcanzaron los mayores niveles de MT tras la exposición al metal. Las hembras de la población de A. salina procedentes de la laguna de La Mata (LMT(B)) fueron las que presentaron una mayor relación molar MT/Cd. La influencia del sexo fue muy coherente en todas las poblaciones estudiadas, siendo las hembras las que mayores contenido de cadmio y niveles de MT alcanzaron tras el tratamiento con metal. Estos resultado considerados en su conjunto demuestran una alta variabilidad fenotípica inter. e intraespecífica y de ahí la importancia de conservar la biodiversidad dentro del género que se ha visto disminuida en los últimos años por la inoculación artificial de especies alóctonas en lagunas que poseen poblaciones naturales y por el cambio climático que ha modificado la dinámica poblacional en salinas de interés comercial. / The aims of this work are to compare the response of the different species and populations in terms of cadmium sensitivity of nauplii, cadmium accumulation and elimination in adults and the basal content of metallothionein (MT) and the induction after cadmium exposure. The statistical procedure (Generalized Linear Models) used to assess the differences in cadmium tolerance of nauplii among populations has shown to be especially useful for this purpose. The results reveal besides a genetic basis for the different susceptibility to cadmium, that there are other factors such as reproductive mode, ploidy and habitat particularities that may account for the response of each of the populations. A first order bicompartimental toxicocinetic model was used in order to assess cadmium accumulation. We have found Artemia to be a cadmium-regulator organism. The consistency in the kinetic accumulation model indicates a well-conserved cadmium accumulation mechanism among studied species and populations. Artemia persimilis was the only one to show a statistically different model, which presents a lower cadmium accumulation rate and bioconcentration factor. Finally, the metallothionein content in adult individuals of Artemia showed a significant effect of cadmium exposure, sex and population origin. For all the studied populations females presented higher molar MT/Cd ratio. The conservation of all existing species and populations of Artemia will help maintain variability in the genus, which includes a broad spectrum of cadmium tolerance responses.

Diapause embryos of the animal extremophile Artemia franciscana, a crustacean, are metabolically dormant and exceptionally tolerant to stressors such as heat and anoxia, characteristics thought to depend on the protective activity of molecular chaperones. RNAi methodology was developed and used to knock down individual molecular chaperones which are normally up-regulated during Artemia diapause. DsRNA and siRNAs injected into females were effective in knocking down proteins in embryos into the fifth release. Five proteins were knocked down including the ?-crystallin related small heat shock proteins (sHsps) p26, ArHsp21 and ArHsp22, artemin, a species-specific chaperone as well as p8 a transcription co-factor. The individual sHsps, artemin and p8 exhibited different roles during cyst development and diapause with only some of these proteins contributing to stress tolerance. p26, for example, enhances stress resistance in Artemia embryos, facilitates embryo development and prevents diapause termination indicated by spontaneous hatching. ArHsp21, another ?-crystallin type small heat shock protein contributes only slightly to freezing and desiccation stress and is not protective during heat stress. DsRNA specific to ArHsp22 is lethal to both male and female adults. Artemin contributes to stress tolerance but to a lesser extent than p26. Artemin also extended the period of time over which cysts were released. Cysts that did not contain p8 were also less stress resistant than those that did contain p8 and hatched upon release 10% for the time, suggesting an important role in diapause. By revealing separate and novel roles for molecular chaperones this work contributes substantially to our understanding of diapause, an important, phylogenetically widespread developmental process.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 39-44). Also available on the World Wide Web.

The effects of water movement or agitation on the biological performance of planktonic organisms under intensive culture have been rarely studied quantitatively. Stagnation or minimum values are considered important in the problem of scale-up based on optimum conditions. Near stagnation, inadequate water movement brings about undesirable effects, e.g. accumulation of metabolites, uneven distribution of feed and low dissolved oxygen concentration. An important mechanism associated with water movement at these conditions is the oxygenation process which defines the oxygen transfer rate from the gas to the water. Experiments were conducted using potable water to determine the overall oxygen mass transfer coefficient in two types of container geometries; a) cylindri-conical tank and b) oblong-shaped center- partitioned raceway. For each type of container, three geometrically similar sizes were investigated with scale ratio of approximately 1:2:3.5. Agitation was induced by the introduction of air into the system. General correlations for both tank geometries were obtained from experimental data and were expressed in terms of the operating and geometric parameters. The correlations are in the form of dimensionless groups (Froude and Reynolds numbers) making them appropriate for scale-up estimates. The general correlations for the overall oxygen mass transfer coefficient were subsequently used to provide the scaling equations to define the operating parameters in different sizes of containers for the culture of brine shrimp in sea water fed with rice bran. The high correlation coefficient obtained for the relationship between total brine shrimp biomass production and the overall mass transfer coefficient applicable to different sizes of both the cylindri-conical tank and the raceway indicates that the overall oxygen mass transfer coefficient is an effective scale-up criterion in brine shrimp culture. / Graduate and Postdoctoral Studies / Graduate