Universiẗat, Diss., 2000--Kiel.

xv, 178 leaves : ill. ; 28 cm Typescript. (Another copy on microfilm is located in Archives) Thesis (Ph.D.) -- University of Oregon Includes vita and abstract Bibliography: leaves 163-178 University of Oregon theses, Dept. of Biology, Ph.D., 1980

Dissertação (mestrado) - Universidade Federal de Santa Catarina. Centro Tecnológico. Programa de Pós-Graduação em Engenharia Ambiental. / Made available in DSpace on 2012-10-21T02:02:57Z (GMT). No. of bitstreams: 0Bitstream added on 2013-07-16T19:26:04Z : No. of bitstreams: 1 199860.pdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Testes de toxicidade com organismos aquáticos constituem uma ferramenta efetiva para avaliação, predição ou detecção dos efeitos dos poluentes sobre os organismos vivos. Reatores UASB (reator anaeróbio de fluxo ascendente) têm sido utilizados para tratamento de efluentes e de lixiviados provenientes de outros sistemas de tratamento. O objetivo deste trabalho foi avaliar a eficiência de um reator experimental do tipo UASB no tratamento de lixiviado, por meio de testes de toxicidade aguda com Daphnia magna. Foram realizadas 16 coletas de efluente ao longo de 6 meses, antes e após o tratamento no reator. Para um melhor entendimento dos possíveis compostos que estão causando a toxicidade do meio foi utilizado o procedimento de Avaliação para Identificação da Toxicidade (AIT). O acompanhamento da toxicidade dos efluentes antes e após o tratamento no reator UASB permitiu detectar alterações provenientes da própria operação do sistema de tratamento. Os resultados indicam que o tratamento de efluentes neste tipo de reator pode reduzir a toxicidade das amostras em até 80%. Contudo, os baixos valores de CE50 encontrados nos testes demonstram a presença de alta toxicidade para todas as amostras. A fase I do AIT demonstrou que os grupos de contaminantes suspeitos são iguais para o afluente e para o efluente, sendo que os prováveis causadores da toxicidade sejam os compostos orgânicos apolares, metais catiônicos e principalmente os sólidos totais dissolvidos. Esforços devem ser direcionados para aumentar a eficiência deste reator, melhorando ainda mais a qualidade dos efluentes tratados neste sistema.

Ho, Sin Chu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 112-135). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.ii / Acknowledgement --- p.iii / Table of Contents --- p.iv / List of Abbreviations --- p.vii / List of Figures --- p.x / List of Tables --- p.xii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Test Organisms: Daphnia magna and Moina macrocopa --- p.1 / Chapter 1.2 --- Biomarkers --- p.2 / Chapter 1.3 --- Heat shock protein (HSP) --- p.4 / Chapter 1.3.1 --- Regulation of hsp70 gene expression --- p.5 / Chapter 1.3.2 --- Review of studies on hsp70 of various species --- p.6 / Chapter 1.3.3 --- Review of studies using molecular methods in Daphnia and Moina --- p.7 / Chapter 1.4 --- Environmental stress studied --- p.9 / Chapter 1.5 --- Objectives --- p.11 / Chapter Chapter 2 --- Materials and Methods --- p.12 / Chapter 2.1 --- Experimental organisms --- p.12 / Chapter 2.2 --- "The effects of temperature, metals and nutritional stress on cladocerans" --- p.13 / Chapter 2.3 --- Demographic measurement --- p.15 / Chapter 2.4 --- Cloning and sequencing of D. magna and M. macrocopa hsp70 --- p.17 / Chapter 2.4.1 --- Acute heat shock --- p.17 / Chapter 2.4.2 --- Total RNA extraction --- p.17 / Chapter 2.4.3 --- Reverse transcription and polymerase chain reaction (PCR) --- p.18 / Chapter 2.4.4 --- Degenerative PCR --- p.21 / Chapter 2.4.5 --- Cloning and sequencing of hsp70 partial sequence --- p.25 / Chapter 2.4.6 --- Rapid amplification of cDNA ends (RACE) --- p.28 / Chapter 2.4.7 --- Confirmation of D. magna and M. macrocopa hsp70 sequences --- p.30 / Chapter 2.5 --- Molecular measurements - heat shock protein 70 gene expression --- p.31 / Chapter 2.5.1 --- Sample collection --- p.31 / Chapter 2.5.2 --- Quantification of cDNA level by real-time PCR --- p.32 / Chapter 2.5.2.1 --- Primer design --- p.32 / Chapter 2.5.2.2 --- Validation of real-time PCR conditions --- p.32 / Chapter 2.5.2.3 --- Determination of hsp70 gene expression levels --- p.35 / Chapter 2.6 --- Statistical analysis --- p.36 / Chapter Chapter 3 --- Results --- p.37 / Chapter 3.1 --- Demographic measurements --- p.37 / Chapter 3.1.1 --- Effects of temperature on life history parameters of M macrocopa --- p.37 / Chapter 3.1.2 --- Effects of temperature on life history parameters of D. magna --- p.40 / Chapter 3.1.3 --- Effects of Metals on life history parameters of M. macrocopa --- p.42 / Chapter 3.1.4 --- Effects of Anabaena on life history parameters of M. macrocopa --- p.47 / Chapter 3.2 --- Cloning and sequencing of hsp70 --- p.50 / Chapter 3.2.1 --- Partial sequences of D. magna and M. macrocopa hsp70 --- p.50 / Chapter 3.2.2 --- Sequences of 3´ة and 5´ة RACE amplified products --- p.53 / Chapter 3.2.3 --- Full sequences of D. magna and M. macrocopa hsp70 --- p.53 / Chapter 3.2.4 --- Phylogenetic relationships of the hsp70 gene --- p.60 / Chapter 3.3 --- Molecular measurements - heat shock protein 70 gene expression --- p.71 / Chapter 3.3.1 --- Validation of real-time PCR conditions --- p.71 / Chapter 3.3.2 --- Effect of temperature stress on hsp70 gene expression levels --- p.76 / Chapter 3.3.3 --- Effect of metals on hsp70 gene expression levels --- p.78 / Chapter 3.3.4 --- Effect of Anabaena on Hsp70 Gene Expression Levels --- p.83 / Chapter Chapter 4 --- Discussion --- p.85 / Chapter 4.1 --- Demographic responses of M. macrocopa and D. magna by different stress --- p.85 / Chapter 4.1.1 --- Effects of temperature on life history parameters --- p.85 / Chapter 4.1.2 --- Effects of metal stress on life history parameters --- p.87 / Chapter 4.1.3 --- Effects of Anabaena on life history parameters --- p.89 / Chapter 4.2 --- Characterization of hsp70 of M. macrocopa and D. magna --- p.92 / Chapter 4.3 --- Hsp70 gene expression in response to different stress --- p.94 / Chapter 4.3.1 --- Effect of temperature stress on hsp70 gene expression levels --- p.94 / Chapter 4.3.2 --- Effect of metals on Hsp70 gene expression levels --- p.97 / Chapter 4.3.3 --- Effect of Anabaena on hsp70 gene expression levels --- p.101 / Chapter 4.4 --- Comparison of demographic and molecular measurements --- p.102 / Chapter 4.5 --- Performance of hsp70 gene expression as a biomarker of environmental stress --- p.106 / Chapter 4.6 --- Conclusion --- p.111 / References --- p.112 / Appendix --- p.136

Lead is an omnipresent pollutant, and its contamination in natural waters is an issue of current regulatory concern throughout the world including Canada. The free divalent ion of lead (Pb2+) is considered to be the most bioavailable and toxic form of lead. Pb2+ is known to be a calcium antagonist in vertebrates including fish. It is believed that lead causes toxicity to freshwater fish primarily by disrupting ionic homeostasis both during acute and chronic waterborne exposure. Lead can also potentially act as a respiratory toxicant since it is known to impair hemoglobin synthesis in both vertebrates. To date, the mechanistic underpinnings of lead accumulation and toxicity in aquatic invertebrates are not well understood, particularly during acute exposure. Therefore, the main objectives of the present study were in two folds: (i) to investigate the mechanisms of waterborne lead uptake, and (ii) to understand the physiological basis of lead toxicity during acute exposure. I used freshwater crustacean, <i>Daphnia magna</i>, as a model freshwater invertebrate species for my study. <i>Daphnia</i> are known to be quite sensitive to metals and widely used as a model species for toxicity assessments. The results of my study suggest that lead inhibits waterborne Ca2+ uptake in <i>Daphnia</i> in a concentration dependent manner, and this inhibition occurs predominantly through a direct competitive interaction. The entry of waterborne Pb2+ in <i>Daphnia</i> likely occurs via both lanthanum-sensitive and verapamil-sensitive epithelial calcium channels. Moreover, my results also indicate that acute waterborne lead exposure severely disrupts both Ca2+ and Na+ uptake from water, which are concomitant with the increase in the lead body burden in <i>Daphnia</i>. Interestingly however, acute exposure to lead does not affect the rate of oxygen consumption in <i>Daphnia</i>, indicating no acute respiratory toxicity of lead. Overall, it appears that lead acts as an ionoregulatory toxicant to <i>Daphnia</i> during acute waterborne exposure.

Lead is an omnipresent pollutant, and its contamination in natural waters is an issue of current regulatory concern throughout the world including Canada. The free divalent ion of lead (Pb2+) is considered to be the most bioavailable and toxic form of lead. Pb2+ is known to be a calcium antagonist in vertebrates including fish. It is believed that lead causes toxicity to freshwater fish primarily by disrupting ionic homeostasis both during acute and chronic waterborne exposure. Lead can also potentially act as a respiratory toxicant since it is known to impair hemoglobin synthesis in both vertebrates. To date, the mechanistic underpinnings of lead accumulation and toxicity in aquatic invertebrates are not well understood, particularly during acute exposure. Therefore, the main objectives of the present study were in two folds: (i) to investigate the mechanisms of waterborne lead uptake, and (ii) to understand the physiological basis of lead toxicity during acute exposure. I used freshwater crustacean, <i>Daphnia magna</i>, as a model freshwater invertebrate species for my study. <i>Daphnia</i> are known to be quite sensitive to metals and widely used as a model species for toxicity assessments. The results of my study suggest that lead inhibits waterborne Ca2+ uptake in <i>Daphnia</i> in a concentration dependent manner, and this inhibition occurs predominantly through a direct competitive interaction. The entry of waterborne Pb2+ in <i>Daphnia</i> likely occurs via both lanthanum-sensitive and verapamil-sensitive epithelial calcium channels. Moreover, my results also indicate that acute waterborne lead exposure severely disrupts both Ca2+ and Na+ uptake from water, which are concomitant with the increase in the lead body burden in <i>Daphnia</i>. Interestingly however, acute exposure to lead does not affect the rate of oxygen consumption in <i>Daphnia</i>, indicating no acute respiratory toxicity of lead. Overall, it appears that lead acts as an ionoregulatory toxicant to <i>Daphnia</i> during acute waterborne exposure.

Female growth, number of eggs and egg growth of Daphnia pulex were studied at four temperatures, 12, 16, 18 and 20°C. I hypothesized that female growth and number of eggs would be lower and the size of the eggs larger in the presence of a predator (kairomones) than in its absence. This effect was expected to be more evident at lower temperatures. I could not find any effect of kairomones on female growth, number of eggs or egg size, although there was a weak tendency for an effect on number of eggs. There was, however, an effect of temperature, regardless of predator treatment (i. e. presence vs absence of kairomones), on number of eggs, where females produced fewer numbers of eggs with increasing temperature. The effect temperature on the number of eggs was not anticipated. Two of the temperatures, 12 and 18°C, were carried out in darkness due to malfunctioning equipment. In addition, for some unknown reason, a high ratio between the number of ephippia and eggs occurred at at16 and 18°C, regardless of predator treatment. These complicating factors (darkness and ephippia) can have had a negative effect on detecting a response by Daphnia to kairomones. / Honors tillväxt, antal ägg och äggens tillväxt hos Daphnia pulex studerades vid fyra olika temperaturer, 12, 16, 18 och 20°C. Min hypotes var att honorna tillväxer mindre och producerar färre ägg, men med större storlek vid närvaro av predator (kairomoner) än utan. Denna effekt förväntades bli tydligare med lägre temperatur. Jag kunde inte påvisa någon effekt av kairomoner varken på honors tillväxt, antal ägg eller storlek på ägg, men det fanns en svag effekt på antalet ägg. Det fanns dock en effekt av temperaturen på antalet ägg oberoende av predatorbehandling (med respektive utan kairomoner), där honorna bildade färre antal ägg med ökande temperatur. Effekten av temperatur på antalet ägg var inte som väntat. Två av temperaturerna, 12 och 18 oC, kördes i mörker pga icke fungerande utrustning. Dessutom, av okänd anledning, var förhållandet mellan antal ephippier och ägg högt vid 16 och 18 oC. Dessa komplicerande faktorer, mörker och andel viloägg, kan ha påverkat den uteblivna effekten av predatorbehandlingen.

This research examined the suitability of the biotic ligand model (BLM) approach for assessing environmental risk in surface waters consisting substantially of treated sewage effluent, and the implications of its use within a compliance-based regulatory framework aimed at controlling discharges of metals into the aquatic environment. The results from a series of Daphnia magna acute copper toxicity assays conducted in an undiluted sewage effluent medium demonstrated that BLMs could predict an acute copper toxicity endpoint with suitable accuracy. This finding contributes further support for the use of BLMs for assessing risk and compliance, even in effluent impacted waters. Additional studies, however, also demonstrated that effluent derived organic matter contained a greater concentration of metal complexing ligands per milligram of dissolved organic carbon than organic matter derived from natural sources. This indicates that effluent derived organic matter offers greater protection against the potentially adverse effects from metals than the protection offered by organic matter derived from natural sources. These studies also demonstrated that improvements in the accuracy of BLM forecasts were achievable by taking these differences into account which, from a regulatory perspective, is also desirable since this enhances the environmental relevance of compliance criteria. These findings therefore justify that consideration for the influence of site-specific metal complexation characteristics should included as part of the regulatory framework within which BLMs will be applied. The implication of the BLM approach for Severn Trent Water Limited is that, as currently proposed, the approach will require a reduction in the concentration of copper in the effluent discharges for a small number of wastewater treatment works (9), whereas for zinc, concentration reductions may be required for numerous treatment works (126).

Increasing temperatures are expected to cause secondary salinisation in freshwater systems, such as the zooplankton community of Churchill, Manitoba. Salinity is a key environmental factor structuring these communities, thus, increasing salinity should cause these communities to change; however, previous research has shown that they are resilient. In order to ascertain how changing salinity will affect these communities I conducted toxicity tests for five crustacean species, individually and in a community setting. I sampled several pools throughout the season to ascertain the salinity level at which those same species were most abundant in the field. While the species had significantly different field distributions along the salinity gradient, the salinity levels associated with maximum densities did not correlate with the lab tolerances. However, lab tolerances were outside the field salinity range, thus providing an unexpected result. Local interactions appear to be very important in determining final community composition along this salinity gradient. / Northern Scientific Training Program, Northern Research Fund

There are two full length variants of the Pokey DNA transposon, PokeyA and PokeyB, and two MITEs, mPok1 and mPok2. Pokey inserts into ribosomal DNA (rDNA) and other genomic locations within the genomes of Daphnia species. I used qPCR to estimate haploid rDNA and Pokey copy number in five Daphnia pulex complex species. In general, rDNA number ranges from ~100 to 500. In four species, low numbers of PokeyA and PokeyB in rDNA and the rest of the genome suggest these elements have low transposition rates, high deletion rates, and/or strong purifying selection against them at the host level. Further, PokeyA may have a higher transposition rate than PokeyB. In these species, mPok1 was not found, and mPok2 is likely inactive. In comparison, the fifth species, D. arenata, which may be a hybrid, has higher Pokey numbers. Higher Pokey numbers could be due to release from epigenetic repression following hybridization. / Ontario Graduate Scholarship in Science and Technology to Shannon H. C. Eagle, Natural Sciences and Engineering Research Council of Canada Discovery Grant to Dr. Teresa J. Crease