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In this 9th contribution to the Fungal Systematics and Evolution series published by Sydowia, the authors formally describe 12 species: Bipolaris chusqueae from Chile (Pleosporales); Cortinarius anomalosimilis and C. brunneoviscidus from Canada and the USA, Inocybe nigroumbonata from Pakistan, Mycena amoena from the Netherlands, Tricholoma imbricatoides and T. pseudoterreum from Canada, T. mcneilii and T. robustipes from Canada and the USA, T. pallens from Canada, the USA, and China (Agaricales); Diversispora alba from Peru (Diversisporales); and Phaeotremella dejopia from the USA (Tremellales). The following new country records are reported: Camptomyces africanus (Laboulbeniales) on Astenus sp. (Coleoptera, Staphylinidae) from Tanzania and Tricholoma fulvimarginatum (Agaricales) from Canada.

The design and evaluation of control programs for soil-transmitted helminths (STHs) is based on surveillance data recording measurements of egg counts in the stool of infected individuals, which underpin estimates of the prevalence and average intensity of infection. There is considerable uncertainty around these measurements and their interpretation. The uncertainty is composed of several sources of measurement error and the limit of detection of fecal smear tests on the one hand, and key assumptions on STH biology on the other hand, including assumptions on the aggregation of worms within hosts and on the impact of density-dependent influences on worm reprod

Because negotiating academic identity is an integral part of tertiary students’ learning process our purpose in this paper is to look at both ‘institutional possibilities for selfhood’, which offer participants opportunities to enrich their academic identities within the context-sensitive, instructional environment, as well as ‘institutional constraints on selfhood’, which draw attention to the ways in which possibilities for selfhood are institutionally limited. To achieve this objective we build on Clark and Ivanič’s conceptualization of writer’s voice seen as both ‘voice as form’ and ‘voice as content’ (Clark and Ivanič’s, 1997). These conceptualizations are represented by the concepts of ‘the discoursal self’, which refers to the social notion of voice and is constructed by a “writer’s affiliation to or unique selection among existing discourse conventions” (ibid.) and ‘the self as author’, which refers to “writers’ expression of their own ideas and beliefs” and reveals an individualistic, expressive and assertive voice (ibid.). Since cultural context is both reflected in and constituted by discourse we call for the development of ‘multivoiced classrooms’ (Dysthe, 1996) which overcome the constraints of a homogeneous, institutionalised discourse. Such an approach to culture in pedagogical contexts will foster the formation of a third space (Kramsch, 1998), a place in which the intercultural speaker (ibid.) is competent in negotiating and mediating discourse, but not necessarily with a native speaker’s competence.

Mathematical models of Redox Flow Batteries (RFBs) can be used to analyze cell performance, optimize battery operation, and control the energy storage system efficiently. Among many other models, physics-based electrochemical models are capable of predicting internal states of the battery, such as temperature, state-of-charge, and state-of-health. In the models, estimating parameters is an important step that can study, analyze, and validate the models using experimental data. A common practice is to determine these parameters either through conducting experiments or based on the information available in the literature. However, it is not easy to investigate all proper parameters for the models through this way, and there are occasions when important information, such as diffusion coefficients and rate constants of ions, has not been studied. Also, the parameters needed for modeling charge-discharge are not always available. In this paper, an efficient way to estimate parameters of physics-based redox battery models will be proposed. Furthermore, this paper also demonstrates that the proposed approach can study and analyze aspects of capacity loss/fade, kinetics, and transport phenomena of the RFB system

Mathematical models of Redox Flow Batteries (RFBs) can be used to analyze cell performance, optimize battery operation, and control the energy storage system efficiently. Among many other models, physics-based electrochemical models are capable of predicting internal states of the battery, such as temperature, state-of-charge, and state-of-health. In the models, estimating parameters is an important step that can study, analyze, and validate the models using experimental data. A common practice is to determine these parameters either through conducting experiments or based on the information available in the literature. However, it is not easy to investigate all proper parameters for the models through this way, and there are occasions when important information, such as diffusion coefficients and rate constants of ions, has not been studied. Also, the parameters needed for modeling charge-discharge are not always available. In this paper, an efficient way to estimate parameters of physics-based redox battery models will be proposed. Furthermore, this paper also demonstrates that the proposed approach can study and analyze aspects of capacity loss/fade, kinetics, and transport phenomena of the RFB system

Mathematical models of Redox Flow Batteries (RFBs) can be used to analyze cell performance, optimize battery operation, and control the energy storage system efficiently. Among many other models, physics-based electrochemical models are capable of predicting internal states of the battery, such as temperature, state-of-charge, and state-of-health. In the models, estimating parameters is an important step that can study, analyze, and validate the models using experimental data. A common practice is to determine these parameters either through conducting experiments or based on the information available in the literature. However, it is not easy to investigate all proper parameters for the models through this way, and there are occasions when important information, such as diffusion coefficients and rate constants of ions, has not been studied. Also, the parameters needed for modeling charge-discharge are not always available. In this paper, an efficient way to estimate parameters of physics-based redox battery models will be proposed. Furthermore, this paper also demonstrates that the proposed approach can study and analyze aspects of capacity loss/fade, kinetics, and transport phenomena of the RFB system

Because negotiating academic identity is an integral part of tertiary students’ learning process our purpose in this paper is to look at both ‘institutional possibilities for selfhood’, which offer participants opportunities to enrich their academic identities within the context-sensitive, instructional environment, as well as ‘institutional constraints on selfhood’, which draw attention to the ways in which possibilities for selfhood are institutionally limited. To achieve this objective we build on Clark and Ivanič’s conceptualization of writer’s voice seen as both ‘voice as form’ and ‘voice as content’ (Clark and Ivanič’s, 1997). These conceptualizations are represented by the concepts of ‘the discoursal self’, which refers to the social notion of voice and is constructed by a “writer’s affiliation to or unique selection among existing discourse conventions” (ibid.) and ‘the self as author’, which refers to “writers’ expression of their own ideas and beliefs” and reveals an individualistic, expressive and assertive voice (ibid.). Since cultural context is both reflected in and constituted by discourse we call for the development of ‘multivoiced classrooms’ (Dysthe, 1996) which overcome the constraints of a homogeneous, institutionalised discourse. Such an approach to culture in pedagogical contexts will foster the formation of a third space (Kramsch, 1998), a place in which the intercultural speaker (ibid.) is competent in negotiating and mediating discourse, but not necessarily with a native speaker’s competence.

Thesis: Ph. D., Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Biology; and the Woods Hole Oceanographic Institution), 2016., Cataloged from PDF version of thesis., Includes bibliographical references (pages 124-131)., Dinoflagellates are a diverse group of single-celled eukaryotic phytoplankton that are important for their unique genetics and molecular biology, the multitude of ecological roles they play, and the ability of multiple species to produce toxins that affect human and ecosystems health. Two dinoflagellate genera, Alexandrium and Gambierdiscus each contain species that can cause human poisoning syndromes, although the methods of toxin transfer, accumulation, and exposure are very different. Gambierdiscus is a benthic organism that produces lipophilic ciguatoxins that can bioaccumulate in coral reef fish and cause ciguatera fish poisoning (CFP) in human consumers. Alexandrium is a planktonic species that produces saxitoxins that can directly accumulate in shellfish and cause paralytic shellfish poisoning (PSP) in humans. Both genera contain multiple species that vary dramatically in toxicity and physiology. Through transcriptomic analysis, this thesis describes the genetic diversity present across dinoflagellates that produce saxitoxin, elaborating on differences in their complement of genes within the saxitoxin biosynthesis pathway. This study demonstrated retention and expression of some of these saxitoxin genes by non-toxic species within Alexandrium, as well as in Gambierdiscus, which does not produce saxitoxins. Furthermore it confirmed the presence of certain transcripts only in toxin-producing species. This thesis then developed novel fluorescence in situ hybridization (FISH) probes that can be used to identify and enumerate six Gambierdiscus species, thereby enabling the community composition of Gambierdiscus to be examined in a quantifiable manner. The probes were tested in the laboratory on cultures, and then successfully applied to field samples from Florida Keys and Hawai'i. Gambierdiscus species are diverse in both their toxicity and optimal temperature ranges for growth. Analysis of Gambierdiscus community composition in an area of variable temperature all, by Kathleen Johnson Pitz., Ph. D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biology, 2017., Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Biology; and the Woods Hole Oceanographic Institution), 2017., Cataloged from PDF version of thesis., Includes bibliographical references., Blooms of the dinoflagellate Alexandrium catenella cause paralytic shellfish poisoning syndrome and present an expanding public health threat. They are inoculated through the germination of benthic cysts, a process regulated by internal and environmental factors, most importantly temperature. Less understood is the effect of temperature conditioning on cyst dormancy cycling, which inhibits germination for long periods. This thesis characterizes the temperature-dependence of both dormancy and germination in natural A. catenella cyst populations from Nauset Marsh (Cape Cod, MA, USA), a small estuarine embayment, and relates these processes to the phenology of blooms there. Through laboratory germination assays, it is shown that dormant A. catenella cysts require a quantifiable amount of chilling to exit dormancy and attain quiescence (i.e. become germinable). A series of experiments compares germination rates of quiescent cysts across a range of temperatures through laboratory experiments and field incubations of raw sediment using plankton emergence traps (PETs). Emergence rates of A. catenella germlings measured by PETs increased linearly with temperature and were comparable to germination under constant laboratory conditions. Total emergence fluxes were much lower than expected, suggesting that germination occurs in a much shallower layer of sediments than typically assumed. The results are synthesized to develop a temperature-dependent model to examine the sensitivity of A. catenella bloom phenology to dormancy-breaking by winter chilling. Notably, the chilling-alleviated dormancy model accurately predicted the timing of quiescence (January) and the variable bloom phenology from multiple blooms in Nauset. Once cysts became quiescent and began to germinate, however, temperatures were typically too cold for growth to exceed losses so there was a several-week lag until bloom development. Years with warmer winters and springs had shorter lag periods and thus significa, by Alexis Dal Fischer., Ph. D.

This is the supplemental PowerPoint for the presentation given at the IIFET Conference in Dar es Salaam, Tanzania. Provides bulleted points regarding the progress, lessons learned, policy recommendations based on Fishery Performance Indicators under evaluation in both developed and developing countries.

This is the supplemental PowerPoint for the presentation given at the IIFET Conference in Dar es Salaam, Tanzania. Provides bulleted points regarding the progress, lessons learned, policy recommendations based on Fishery Performance Indicators under evaluation in both developed and developing countries.

This is the supplemental PowerPoint for the presentation given at the IIFET Conference in Dar es Salaam, Tanzania. Provides bulleted points regarding the progress, lessons learned, policy recommendations based on Fishery Performance Indicators under evaluation in both developed and developing countries.

This is the supplemental PowerPoint for the presentation given at the IIFET Conference in Dar es Salaam, Tanzania. Provides bulleted points regarding the progress, lessons learned, policy recommendations based on Fishery Performance Indicators under evaluation in both developed and developing countries.

Offers an overview of the U.S. legal services industry and research questions about innovations, including in unbundling and outsourcing services, multidisciplinary partnerships, and alternative litigation finance, as well as the role of regulation.

Offers an overview of the U.S. legal services industry and research questions about innovations, including in unbundling and outsourcing services, multidisciplinary partnerships, and alternative litigation finance, as well as the role of regulation.

Offers an overview of the U.S. legal services industry and research questions about innovations, including in unbundling and outsourcing services, multidisciplinary partnerships, and alternative litigation finance, as well as the role of regulation.

Offers an overview of the U.S. legal services industry and research questions about innovations, including in unbundling and outsourcing services, multidisciplinary partnerships, and alternative litigation finance, as well as the role of regulation.

Strong principals are central to improving schools—indeed, leadership is second only to teaching among school-related factors that influence student achievement. Districts struggle, however, to develop a sufficient pool of highly capable principals. While research has identified strategies that are effective in preparing and supporting school leaders, few districts have pulled together a coherent set of strategies to form a pipeline to the principalship.Recognizing the need to improve the supply of high-quality principals, The Wallace Foundation launched the Principal Pipeline Initiative (PPI) in 2011. The goal was to test the proposition that districts could produce a large cadre of strong novice principals by making a concerted effort to implement a set of interrelated policies and practices, and that doing so would positively affect school outcomes. Participating districts focused on implementing four key components:? Adopting standards of practice and performance to guide principal preparation, hiring, evaluation, and support? Improving the quality of preservice preparation for principals? Using selective hiring and placement practices to match principal candidates with schools? Implementing on-the-job evaluation and support for novice principals (those in their first three years on the job)Six large districts received multi-year grants of $8.5 million to $13.25 million from the foundation to cover a portion of the start-up costs of developing a principal pipeline. The districts were selected partly because they had already adopted some policies and practices consistent with the PPI components. The foundation also provided technical assistance. The PPI sought not only to institute, grow, and sustain the key components within each participating district, but also to generate examples that other districts might follow.

PR, IFPRI5; PBS, EPTD, Genetically engineered (GE) crops were first introduced commercially in the 1990s. After two decades of production, some groups and individuals remain critical of the technology based on their concerns about possible adverse effects on human health, the environment, and ethical considerations. At the same time, others are concerned that the technology is not reaching its potential to improve human health and the environment because of stringent regulations and reduced public funding to develop products offering more benefits to society. While the debate about these and other questions related to the genetic engineering techniques of the first 20 years goes on, emerging genetic-engineering technologies are adding new complexities to the conversation.

PR, IFPRI4; CRP2; A Ensuring Sustainable food production; D Transforming Agriculture; E Building Resilience; Land Resource Management for Poverty Reduction, EPTD; PIM, CGIAR Research Program on Policies, Institutions, and Markets (PIM)

ERDC TR-15-1 ERDC Center-Directed Research Program Field Biogeochemical Measurements in Support of Remote Sensing Signatures and Characterization of Permafrost Terrain Integrated Technologies for Delineating Permafrost and Ground-State Conditions Engineer Research and Development Center Robyn A. Barbato, John E. Anderson, Jarrod D. Edwards, Karen L. Foley, Charles M. Reynolds, and Thomas A. Douglas March 2015 Approved for public release; distribution is unlimited. The U.S. Army Engineer Research and Development Center (ERDC) solves the nation’s toughest engineering and environmental challenges. ERDC develops innovative solutions in civil and military engineering, geospatial sciences, water resources, and environmental sciences for the Army, the Department of Defense, civilian agencies, and our nation’s public good. Find out more at www.erdc.usace.army.mil. To search for other technical reports published by ERDC, visit the ERDC online library at http://acwc.sdp.sirsi.net/client/default.ERDC Center-Directed Research Program ERDC TR-15-1 March 2015 Field Biogeochemical Measurements in Support of Remote Sensing Signatures and Characterization of Permafrost Terrain Integrated Technologies for Delineating Permafrost and Ground-State Conditions Robyn A. Barbato, Karen L. Foley, and Charles M. Reynolds Cold Regions Research and Engineering Laboratory (CRREL) U.S. Army Engineer Research and Development Center (ERDC) 72 Lyme Road Hanover, NH 03755-1290 John E. Anderson and Jarrod D. Edwards Geospatial Research Laboratory (GRL) U.S. Army Engineer Research and Development Center (ERDC) 7701 Telegraph Road Alexandria, VA 22315-3864 Thomas A. Douglas Cold Regions Research and Engineering Laboratory (CRREL) U.S. Army Engineer Research and Development Center (ERDC) Building 4070, Second Avenue Fort Wainwright, AK 99703 Final Report Approved for public release; distribution is unlimited. Prepared for Headquarters, U.S. Army Corps of Engineers Washington, DC 20314-1000 Under ERDC Cen

PR, IFPRI3; ISI; A Ensuring Sustainable food production; CRP2, EPTD; PIM, CGIAR Research Program on Policies, Institutions, and Markets (PIM)

PR, IFPRI3; ISI; CRP2; Land Resource Management for Poverty Reduction, EPTD; PIM, CGIAR Research Program on Policies, Institutions, and Markets (PIM)

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Ocean Engineering; and the Woods Hole Oceanographic Institution), February 2001., Includes bibliographical references., by Nicole Jane Poulton., Ph.D.

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Ocean Engineering; and the Woods Hole Oceanographic Institution), February 2001., Includes bibliographical references., by Nicole Jane Poulton., Ph.D.

International Computer Music Conference Proceedings: vol. 1992, (dlps) bbp2372.1992.095, http://hdl.handle.net/2027/spo.bbp2372.1992.095, This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. Please contact mpub-help@umich.edu to use this work in a way not covered by the license.

This first report of an ongoing evaluation of The Wallace Foundation's Principal Pipeline Initiative describes the six participating school districts' plans and activities during the first year of their grants. The evaluation, conducted by Policy Studies Associates and the RAND Corporation, isintended to inform policy makers and practitioners about the process of carrying out new policies and practices for school leadership and about the results of investments in the Principal Pipeline Initiative. This report is based on collection and analysis of qualitative data, including the districts' proposals, work plans, and progress reports and semi-structured interviews in spring 2012 with 91 administrators employed by districts and their partner institutions. Leaders in all districts report wanting to enlarge their pools of strong applicants for principal positions and to identify and cultivate leadership talent as early as possible in educators' careers.Districts are actively working on allrequired pipeline components: (1) with stakeholder participation, they have developed standards and identified competencies for principals, which they plan to use to guide principal training, hiring, evaluation, and support; (2) they are initiating or strengthening partnerships with university training programs; (3) for hiring, they have standard performance tasks and are developing systems to capture data on candidates' experience; (4) they have diagnostic evaluation tools and are working to build the capacity of principals' supervisors and mentors to support principals' skill development. In addition, all are also bolstering district-run training programs for graduates of university training programs who aspire to become principals.

This first report of an ongoing evaluation of The Wallace Foundation's Principal Pipeline Initiative describes the six participating school districts' plans and activities during the first year of their grants. The evaluation, conducted by Policy Studies Associates and the RAND Corporation, isintended to inform policy makers and practitioners about the process of carrying out new policies and practices for school leadership and about the results of investments in the Principal Pipeline Initiative. This report is based on collection and analysis of qualitative data, including the districts' proposals, work plans, and progress reports and semi-structured interviews in spring 2012 with 91 administrators employed by districts and their partner institutions. Leaders in all districts report wanting to enlarge their pools of strong applicants for principal positions and to identify and cultivate leadership talent as early as possible in educators' careers.Districts are actively working on allrequired pipeline components: (1) with stakeholder participation, they have developed standards and identified competencies for principals, which they plan to use to guide principal training, hiring, evaluation, and support; (2) they are initiating or strengthening partnerships with university training programs; (3) for hiring, they have standard performance tasks and are developing systems to capture data on candidates' experience; (4) they have diagnostic evaluation tools and are working to build the capacity of principals' supervisors and mentors to support principals' skill development. In addition, all are also bolstering district-run training programs for graduates of university training programs who aspire to become principals.

Non-PR, IFPRI2, EPTD, This study employs IFPRI’s IMPACT model to generate projections of global fi sh supply and demand. IMPACT covers the world in 115 model regions for a range of agricultural commodities, to which fi sh and fi sh products are added for this study. As is the case with most global modeling work, an important value that IMPACT brings to this study is an internally consistent framework for analyzing and organizing the underlying data. However, there are known data and methodology issues that arise from choices made by the key researchers for the purposes of maintaining computational tractability, internal analytical consistency, and overall simplicity.

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2005., Page 296 blank., Includes bibliographical references., Marine thecate heterotrophic dinoflagellates likely play an important role in the consumption of primary productivity and in the trophic structure of the plankton, yet we know little about these species. This thesis expanded our understanding of the autecology and evolutionary history of the Protoperidinium and diplopsalids. The distributions of Protoperidinium species off the southwestern coast of Ireland were influenced by physical oceanographic conditions coupled with the availability of preferred prey. The distributions of individual Protoperidinium species varied widely from the distribution of total Protoperidinium, indicating differences in ecologies among species. Certain species of Protoperidinium co-occurred with known preferred phytoplankton prey species. Concentrations of other Protoperidinium species were not related to those of any particular phytoplankton species, indicating that these Protoperidinium may rely on phytoplankton or other food sources beyond those already known, may not be species specific selective feeders, or may have become uncoupled from their preferred prey. The description of the sexual and asexual life history of Protoperidinium steidingerae provided the first account of the life history of any Protoperidinium species., (cont.) Asexual division occurred by eleutheroschisis within a temporary, immotile cyst, yielding two daughter cells. Daughter cells were initially round and half to two-thirds the size of parent cells, then rapidly increased in size, forming horns before separating. Sexual reproduction was constitutive in clonal cultures, indicating that the species may be homothallic. Fusing gametes were isogamous, and resulted in a planozygote with two longitudinal flagella. Hypnozygotes had a mandatory dormancy period of ca. 70 days. Germination resulted in planomeiocytes with two longitudinal flagella. Nuclear cyclosis may occur in the planomeiocyte stage. A high level of morphological diversity among life history stages of P. steidingerae has led to mis-classification and taxonomic inaccuracy of Protoperidinium species identified from field samples. The large subunit ribosomal DNA (LSU rDNA) molecular phylogeny of the heterotrophic dinoflagellates revealed that the genus Protoperidinium appeared to be recently diverged within the dinoflagellates. In maximum parsimony and neighbor joining analysis, Protoperidinium formed a monophyletic group, evolving from diplopsalid dinoflagellates., (cont.) In maximum likelihood and Bayesian analyses, however, Protoperidinium was polyphyletic, as the lenticular, diplopsalid heterotroph, Diplopsalis lenticula Bergh, was inserted within the Protoperidinium clade basal to Protoperidinium excentricum (Paulsen) Balech, and Preperidinium meunieri (Pavillard) Elbrichter fell within a separate clade as a sister to the Oceanica section and Protoperidinium steidingerae Balech. In all analyses, the Protoperidinium were divided into two major clades, with members in the Oceanica group and subgenus Testeria in one clade, and the Excentrica, Conica, Pellucida, Pyriforme, and Divergens sections in another clade. The LSU rDNA molecular phylogeny supported the historical morphologically determined sections, but not a simple morphology-based model of evolution based on thecal plate shape. LSU rDNA gene sequences are frequently used to infer the phylogeny of organisms. The many copies of the LSU rDNA found in the genome are thought to be kept homogenous by concerted evolution. In Protoperidinium species, however, there was high intragenomic diversity in the D1-D6 region of the LSU rDNA. For each species, the clone library was usually comprised of one highly represented copy and many unique sequences., (cont.) Sequence differences were primarily characterized by single base pair substitutions, single base pair insertion/deletions (indels), and/or large indels. Phylogenetic analysis of all clones gave strong support for monophyly of the polymorphic copies of each species, and recovered the same species tree as an analysis using just one sequence per species. Analysis of LSU rDNA gene expression in three species by RT-PCR indicated that copies with fewer substitutions and fewer and smaller indels are expressed, and that 50% or more of the copies are pseudogenes. High intraspecific and intraindividual LSU rDNA sequence variability could lead to inaccurate species phylogenies and over-estimation of species diversity in environmental sequencing studies. This thesis has explored the ecology, life history, molecular phylogeny, and intraspecific DNA sequence variability of marine thecate heterotrohic dinoflagellates using a wide range of methodologies, including field sampling, culturing, microscopy, morphological analyses, histological staining, and molecular biology. The work here has broadened our understanding of the Protoperidinium and diplopsalids, providing new insights into the ecological and evolutionary relationships of these heterotrophs with other plankton species., by Kristin Elizabeth Gribble., Ph.D.

Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2007., Includes bibliographical references., Paralytic shellfish poisoning (PSP) is a human intoxication associated with the consumption of shellfish contaminated with a family of neurotoxins called saxitoxins. Many species in the dinoflagellate genus Alexandrium have been shown to produce these toxins. Here I report the first case of a culture of Alexandrium that has completely lost the ability to produce saxitoxins. The loss of toxicity was accompanied by a reduction in growth capability. A subculture of this isolate maintains the ability to produce toxins and to grow at rates and to cell abundances that were characteristic of the original Alexandrium culture. The growth and toxicity differences in the two isolates were demonstrated to be a property of the dinoflagellate itself and were not dependent on the different bacterial symbionts associated with each culture. The pair of subcultures is a novel experimental system to study gene expression related to toxin production and growth in dinoflagellates. The products of gene expression were analyzed in the two subcultures of Alexandrium grown under the same conditions, but where toxicity and growth differ. At the metabolome level, compounds were identified that were unique to the non-toxic isolate; their emergence may be correlated to a disruption of the biosynthetic pathway for PSP toxins., (cont.) These compounds share some characteristics and potential structural similarities with saxitoxins, though they are not any of the known toxin derivatives. Difference gel electrophoresis (DIGE) identified proteins differentially expressed between the two subcultures. Identification of some of these proteins was possible by searching the expressed sequence tag (EST) database for dinoflagellates. Proteins shown to be down-regulated in the non-toxic, slower growing subculture are all enzymes from the Calvin cycle, which may explain the limited growth of the non-toxic isolate. Other unknown, differentially expressed proteins may relate to the loss of toxicity, but their identity and function remain unresolved., by Claudia A. Martins., Ph.D.

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2005., Page 296 blank., Includes bibliographical references., Marine thecate heterotrophic dinoflagellates likely play an important role in the consumption of primary productivity and in the trophic structure of the plankton, yet we know little about these species. This thesis expanded our understanding of the autecology and evolutionary history of the Protoperidinium and diplopsalids. The distributions of Protoperidinium species off the southwestern coast of Ireland were influenced by physical oceanographic conditions coupled with the availability of preferred prey. The distributions of individual Protoperidinium species varied widely from the distribution of total Protoperidinium, indicating differences in ecologies among species. Certain species of Protoperidinium co-occurred with known preferred phytoplankton prey species. Concentrations of other Protoperidinium species were not related to those of any particular phytoplankton species, indicating that these Protoperidinium may rely on phytoplankton or other food sources beyond those already known, may not be species specific selective feeders, or may have become uncoupled from their preferred prey. The description of the sexual and asexual life history of Protoperidinium steidingerae provided the first account of the life history of any Protoperidinium species., (cont.) Asexual division occurred by eleutheroschisis within a temporary, immotile cyst, yielding two daughter cells. Daughter cells were initially round and half to two-thirds the size of parent cells, then rapidly increased in size, forming horns before separating. Sexual reproduction was constitutive in clonal cultures, indicating that the species may be homothallic. Fusing gametes were isogamous, and resulted in a planozygote with two longitudinal flagella. Hypnozygotes had a mandatory dormancy period of ca. 70 days. Germination resulted in planomeiocytes with two longitudinal flagella. Nuclear cyclosis may occur in the planomeiocyte stage. A high level of morphological diversity among life history stages of P. steidingerae has led to mis-classification and taxonomic inaccuracy of Protoperidinium species identified from field samples. The large subunit ribosomal DNA (LSU rDNA) molecular phylogeny of the heterotrophic dinoflagellates revealed that the genus Protoperidinium appeared to be recently diverged within the dinoflagellates. In maximum parsimony and neighbor joining analysis, Protoperidinium formed a monophyletic group, evolving from diplopsalid dinoflagellates., (cont.) In maximum likelihood and Bayesian analyses, however, Protoperidinium was polyphyletic, as the lenticular, diplopsalid heterotroph, Diplopsalis lenticula Bergh, was inserted within the Protoperidinium clade basal to Protoperidinium excentricum (Paulsen) Balech, and Preperidinium meunieri (Pavillard) Elbrichter fell within a separate clade as a sister to the Oceanica section and Protoperidinium steidingerae Balech. In all analyses, the Protoperidinium were divided into two major clades, with members in the Oceanica group and subgenus Testeria in one clade, and the Excentrica, Conica, Pellucida, Pyriforme, and Divergens sections in another clade. The LSU rDNA molecular phylogeny supported the historical morphologically determined sections, but not a simple morphology-based model of evolution based on thecal plate shape. LSU rDNA gene sequences are frequently used to infer the phylogeny of organisms. The many copies of the LSU rDNA found in the genome are thought to be kept homogenous by concerted evolution. In Protoperidinium species, however, there was high intragenomic diversity in the D1-D6 region of the LSU rDNA. For each species, the clone library was usually comprised of one highly represented copy and many unique sequences., (cont.) Sequence differences were primarily characterized by single base pair substitutions, single base pair insertion/deletions (indels), and/or large indels. Phylogenetic analysis of all clones gave strong support for monophyly of the polymorphic copies of each species, and recovered the same species tree as an analysis using just one sequence per species. Analysis of LSU rDNA gene expression in three species by RT-PCR indicated that copies with fewer substitutions and fewer and smaller indels are expressed, and that 50% or more of the copies are pseudogenes. High intraspecific and intraindividual LSU rDNA sequence variability could lead to inaccurate species phylogenies and over-estimation of species diversity in environmental sequencing studies. This thesis has explored the ecology, life history, molecular phylogeny, and intraspecific DNA sequence variability of marine thecate heterotrohic dinoflagellates using a wide range of methodologies, including field sampling, culturing, microscopy, morphological analyses, histological staining, and molecular biology. The work here has broadened our understanding of the Protoperidinium and diplopsalids, providing new insights into the ecological and evolutionary relationships of these heterotrophs with other plankton species., by Kristin Elizabeth Gribble., Ph.D.