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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An investigation of the diel swimming activity of Hyalella azteca (Saussure) in Lake Mendota, Wisconsin

Mullen, Robert Edward. January 1970 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
2

Proteomic-Based Assessment of Estrogenic Endocrine Disruption in Hyalella azteca

Prokai, Marcel Laszlo 12 1900 (has links)
In our studies, we used the environmentally important crustacean Hyalella azteca (H. azteca) as an invertebrate model and 17β-estradiol (E2) as a representative of environmental estrogenic endocrine disrupting compounds (EDCs) for proteomics-based investigations of endocrine disruptions in an aquatic ecosystem. Using liquid chromatography coupled with tandem mass spectrometry, our investigation focused for the first time on the recognition of biological and molecular events affected by E2 exposure with the long-term goal of identifying panels of potential biomarkers for environmental estrogenic endocrine disruption. We analyzed E2-induced changes in protein expressions in female and male H. azteca using label-free quantitative proteomics. With discovery-driven shotgun approach, we identified over 50 proteins that were affected by E2 in a sex-specific manner in our model organism. We selected four E2-regulated proteins (vitellogenin, cuticle protein CPR RR, titin and clumping factor A-like protein) for validation by parallel reaction monitoring-based targeted proteomics. Altogether, our proteomics studies have characterized for the first time E2-triggered endocrine disruption in H. azteca and recognized sex-specific changes in the male and female H. azteca's proteome after aquatic exposure to this estrogen. Through targeted proteomics, we were also able to quantitatively characterize a panel of selected proteins that showed distinctive sex-specific responses to this estrogen. We also mapped differentially expressed proteins to protein interaction networks and biological processes through Ingenuity® Pathway Analysis to indicate the future applicability of a bioinformatics-supported strategy focusing on potential environmental biomarker discovery and development using H. azteca as a model.
3

Benthic Macroinvertebrate Susceptibility to Trout Farm Effluents

Roberts, Lenn Darrell 23 September 2005 (has links)
The direct effects of a Virginia trout farm on benthic macroinvertebrates were examined using multiple approaches. Static laboratory tests with the amphipod, Hyallela azteca, were conducted with exposures to water taken from a spring, effluent above a sedimentation basin, and effluent below a sedimentation basin. On-site mesocosms were constructed to expose previously colonized artificial substrates to the same treatments as the laboratory tests. Flat-headed mayflies were also collected from a nearby stream and transported to the mesocosms for a 10 day exposure. There was no significant difference between treatments in the laboratory tests after 20 days, but after 28 days the control was significantly lower than the above sedimentation basin treatment in one test. In the multispecies field tests, a clear decrease in total invertebrate abundance and EPT abundance was seen in the effluent treatments compared to the spring water treatments, with a slight improvement in survival in the treatment below the sedimentation basin. However, only total invertebrate abundance after 21 days produced statistically significant differences. A significant difference was detected between the effluent and the spring treatments in the flat-headed mayfly field test. We suggest that the effects seen in this study do not explain the lack of taxa richness in the receiving stream. The main cause of mortality from trout effluents appears to be solids accumulating upon the organisms, and sedimentation basins should be effective best management practices for protecting macroinvertebrates. / Master of Science

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