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The obligate stem parasite Cuscuta pentagona is able to take up host plant mRNA through a specialized organ known as the haustorium. Direct cell-to-cell symplastic connections between two different organisms are rare, and the translocation mechanisms and fate of these RNAs in the parasite is not understood. To characterize this phenomenon, mobile Arabidopsis and tomato mRNAs were identified from microarray and transcriptome sequencing projects and quantified in the host-parasite system. Mobile RNAs were quantified using real time (qRT)-PCR and were found to vary substantially in their rate of uptake and distribution in the parasite. Transcripts of tomato Gibberellic Acid Insensitive (SlGAI) and Cathepsin D Protease Inhibitor (SlPI) can be traced over 30-cm of parasite stem. SlPI was abundant in the C. pentagona stem, but the number of copies decreased substantially within the first eight hours post detachment. Additional studies of mobile RNAs from Arabidopsis, Translationally Controlled Tumor Protein (AtTCTP), Auxin Response Factor (AtARF) and a Salt-inducible Zinc Finger Protein (AtSZFP) supported the idea that mRNA molecules differ in their mechanisms of uptake and mobility between host and parasite. Known phloem-mobile RNAs (SlGAI and AtTCTP) have uptake patterns that differ from each other as well as from other RNAs that are not reported to be phloem mobile (SlPI and AtSZF1). The function of RNAs in plants extend beyond protein translation to include post transcriptional gene silencing or long distance signaling, and mobile RNA in C. pentagona systems offers novel insights into this aspect of plant biology. Studies of cell-to-cell trafficking of RNAs and other macromolecules would be facilitated by the ability to manipulate individual cells. To this end, work was initiated to explore alternative approaches to understanding single cell biology using laser-mediated approaches. Optoperforation, or the use of multiphoton processes to form quasi-free electron plasmas to initiate transient pore formation in plasma membranes, has been demonstrated, but not in cells of an intact plant. This work details a protocol for optoperforation of Arabidopsis epidermal cells to allow for uptake of external dye-labeled dextrans and retention for up to 72 hours, and has the potential for transformation and molecular tagging applications. / Ph. D.

Species interact and exploit one another for a number of reasons, including transportation, shelter or nutrition such as in parasitic relationships. Parasitism is an important aspect in life and is common in all taxonomic groups. Parasites are often host-specific and can be endoparasites or ectoparasites. The phylum Platyhelminthes includes the class Monogenea or monogenetic parasitic flukes. Monogeneans are mainly parasitic in fish but the family Polystomatidae, also commonly referred to as polystomes, are found on the skin and gills of the Australian lungfish, tadpole gills, kidneys and urinary bladders of frogs, gills and skin of salamanders, cloaca and phalodeum of caecileans, on the eye, in the nose, mouth or urinary bladder of freshwater turtles and on the eye of the hippopotamus. Polystomes have a cosmopolitan distribution, and are found on all hospitable continents. Polystome species were first discovered in the 1758. Between 1961 and 1980 French researchers focussed on Central and West Africa and described a large number of parasites. Polystome discovery has steadily decreased in the last 30 years, however despite this, new species are still being discovered annually. The list of currently known polystomes is most likely only a small portion of the species that exists. Wherever scientists searched for polystomes, new species were discovered. The current distribution of polystomes is not at all a true reflection of their global distribution but merely an indication of research effort. Monogenean flatworms exhibit many variations in the morphology of the intestinal tract. These parasites display two distinct diets, where one group mainly feeds on blood while the other mainly feeds on mucus and epithelial tissues. Thus the feeding habits and other factors such as the shape of the caeca, the presence/absence and number of medial and lateral diverticula as well as anastomosis may play a role in the morphology of the intestinal tract, which can be used as a classification tool to classify polystome species into specific genera. The three aims of the study were to:  Conduct a literature study to compile a species list and source of information on all valid polystome taxa.  Review the intestine shape of all polystomes and evaluate it as a taxonomic characteristic.  Conduct a species description of a new North American chelonian polystome belonging to the genus Polystomoides. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Species interact and exploit one another for a number of reasons, including transportation, shelter or nutrition such as in parasitic relationships. Parasitism is an important aspect in life and is common in all taxonomic groups. Parasites are often host-specific and can be endoparasites or ectoparasites. The phylum Platyhelminthes includes the class Monogenea or monogenetic parasitic flukes. Monogeneans are mainly parasitic in fish but the family Polystomatidae, also commonly referred to as polystomes, are found on the skin and gills of the Australian lungfish, tadpole gills, kidneys and urinary bladders of frogs, gills and skin of salamanders, cloaca and phalodeum of caecileans, on the eye, in the nose, mouth or urinary bladder of freshwater turtles and on the eye of the hippopotamus. Polystomes have a cosmopolitan distribution, and are found on all hospitable continents. Polystome species were first discovered in the 1758. Between 1961 and 1980 French researchers focussed on Central and West Africa and described a large number of parasites. Polystome discovery has steadily decreased in the last 30 years, however despite this, new species are still being discovered annually. The list of currently known polystomes is most likely only a small portion of the species that exists. Wherever scientists searched for polystomes, new species were discovered. The current distribution of polystomes is not at all a true reflection of their global distribution but merely an indication of research effort. Monogenean flatworms exhibit many variations in the morphology of the intestinal tract. These parasites display two distinct diets, where one group mainly feeds on blood while the other mainly feeds on mucus and epithelial tissues. Thus the feeding habits and other factors such as the shape of the caeca, the presence/absence and number of medial and lateral diverticula as well as anastomosis may play a role in the morphology of the intestinal tract, which can be used as a classification tool to classify polystome species into specific genera. The three aims of the study were to:  Conduct a literature study to compile a species list and source of information on all valid polystome taxa.  Review the intestine shape of all polystomes and evaluate it as a taxonomic characteristic.  Conduct a species description of a new North American chelonian polystome belonging to the genus Polystomoides. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

This thesis focuses on the trajectory of the biomedical concept of virulence from 1880 until the present. Following the concept across disciplinary boundaries, from a longue durée history perspective, it explores how virulence was shaped through two distinct, although sometimes overlapping, “styles of reasoning”. Located at the intersection of several distinct research domains in biology and medicine, the concept of virulence provides, in addition, a window into the complex and changing relations between evolutionary biology and the health sciences (broadly construed) over the past two centuries. Moving back and forth between field experiments and the laboratory, this work examines, through the lens of historical epistemology, the emergence of what I call the molecular and the ecological styles, and their respective conceptual practices. It focuses on the ways in which these styles operationalize the distinction between virulent or avirulent organisms in sometimes opposite sense: Whereas in the molecular (or endogenous) style the expression of virulence is explained by properties of internal structures of the infectious agent (e.g. polysaccharide capsule, virulence gene, or pathogenicity island), the concept of virulence in the ecological (or exogenous) style reflects, in contrast, either a lack of adaptation between two species (avirulence hypothesis) or the existence of one or more ecological compromises between, say, the mode of transmission of a pathogen and its host’s recovery rate (trade-off model). Both styles can be said to originate in the medical bacteriology of the late-nineteenth century, but while the former grew mostly out of the work of Louis Pasteur and Robert Koch in Europe, the latter was primarily shaped by Theobald Smith in the United States. Nearly a century later, the introduction of the category of emerging infectious disease within public health discourses in the mid-1990s facilitated a rapprochement between the two styles that had, so far, remained apart. Employing the 1918–1919 influenza pandemic as an example in which to illustrate the trajectory of the molecular and the ecological approaches, the diversity of explanatory schemes developed to account for the pandemic’s exceptional virulence points toward an unresolved, and yet productive, epistemic tension between the two styles, on the one hand, and the intrinsic polarity of the concept of virulence itself, on the other.

Understanding how floral traits covary with one another and with mating patterns is an important step in understanding how and why mating systems evolve. I examined the evolution of floral and mating system variation in Camissoniopsis cheiranthifolia (Onagraceae), a species that exhibits divergence in key floral traits expected to be associated with variation in the relative importance of outcrossing vs. self-fertilization. I combined geographic surveys of floral variation with genetic estimates of the proportion of seeds outcrossed (t) and confirmed that t covaried with corolla width and herkogamy in a predictable way both within and among populations. I then performed geographic surveys, manipulative experiments and genetic analyses to evaluate the potential role that; inbreeding depression (ID), interactions between flowers, pollinators and florivores, and reproductive assurance (RA) may have played in shaping and/or maintaining the geographic pattern of mating system variation in this species. The main selective factor maintaining outcrossing in large flowered (LF) populations appears to be ID, which was much stronger in LF compared to small flowered (SF) populations. These results are also consistent with purging of ID in SF populations. Increased selfing appeared to alleviate pollen limitation (PL) because it was associated with higher and less variable fruit set and reduced florivory by a microlepidopteran. However, evidence that florivores preferentially attacked larger flowers was equivocal. LF experienced stronger PL than SF populations suggesting that one condition for the evolution of selfing via RA is met in outcrossing populations. Floral emasculation experiments revealed that the timing of selfing also covaried with flower size among and within populations. SF self-pollinate before flowers open but LF do not, suggesting that selfing evolved in response to chronic outcross PL. Negative side effects of emasculation were detected which prevented a clear interpretation of the RA value of selfing. Given that much of what is known about RA comes from emasculation experiments, my results suggest that the assumptions of this approach, which are rarely verified, require more serious consideration. Taken together my results suggest that C. cheiranthifolia has evolved multiple stable mixed mating systems perhaps in response to selection for RA. / Thesis (Ph.D, Biology) -- Queen's University, 2012-12-30 14:13:46.366

Main aim of this master thesis is to map the situation of parasitism teaching in elementary and grammar schools. Thats why it contains analysis of reachable elementary and grammar school textbooks - it informs about various kinds of rating the textbooks, which can help both - current and future teachers of biology - to better know and identify reachable textbooks and choose the right ones for the parasitism teaching. It also contains test results of students parasitism knowledge, which are generally very good. Anyway they should learn much more about parazite's manipulation of their host behavior. Other part of my master thesis shows the results of grammar school teachers-filled questionnaires. All questionnaire results (teachers' and students') show that there can be an improvement in parasitism teaching. In next section you can find the Framework Education Programme analysis, own educational programme draft - workbooks, didactic games and powerpoint presentations. Thanks to the realization of teaching the parazites manipulation of their host behavior I found out that students' interest in the topic is quite big so it would be a shame not to share this newly explored area of parasitism with them. Key words: parasite, host, manipulation hypothesis, questionnaires, parasitism teaching

The effect of parasitism on the individual, and on a population, is one of the least understood and poorly studied areas of fish ecology. Parasites compete for maternal energetic reserves required for the production of viable eggs and offspring; thus parasites can directly influence population dynamics by lowering the number of offspring that survive to produce. The goal of this work was to explore the effect of parasitism on the reproductive potential of fish. Traditional measures of somatic energy reserves and body condition were examined along with newer measures of fatty acids present in eggs to approximate reproductive potential. Eighty female common snook, Centropomus undecimalis, were collected during spawning season (mid April to mid October) from four spawning aggregations along the southeastern coast of Florida and examined for a suite of biological, reproductive, and parasite infection measures. General linear models were used to model somatic indices, body condition, fatty acid composition and the ratios of fatty acids in eggs as a function of parasite infection parameters, host age, capture location, capture month and year. All fish were included in the somatic indices and body condition analysis while a subset of 40 fish were used in the analysis on fatty acid composition and the ratios of fatty acids in eggs. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

O tratamento da doença de Chagas é recomendado em pacientes na fase crônica indeterminada com a finalidade de reduzir a carga parasitária, o desenvolvimento de manifestações clínicas tais como as cardiomiopatias e episódios de reativação. Os métodos sorológicos constituem o padrão ouro para a definição de cura pós tratamento, porém não avaliam a carga parasitária tecidual, podendo demorar muitos anos até a soronegativação, enquanto os métodos parasitológicos apresentam baixa sensibilidade na fase crônica. No presente estudo a hemocultura, microscopia ótica, PCR em tempo real (qPCR) e imunoistoquímica foram usados para monitorar a carga parasitária em sangue e órgãos de camundongos Swiss infectados com 2x103 formas da cepa Y de T. cruzi. Foram analisados animais não tratados (NT), tratados somente na fase aguda (TA), somente na fase crônica (TC) e em ambas as fases da infecção (TAC). O tratamento foi realizado com 100 mg/Kg/dia de benznidazol durante 20 dias consecutivos. Amostras foram coletadas no 13º dpi, 26º dpi e 61º dpi (pico da fase aguda, final da fase aguda e fase crônica). Na fase crônica da infecção a microscopia ótica e a hemocultura encontraram 0 e 25% de amostras positivas, respectivamente, e com a qPCR as cargas parasitárias de todas amostras foram quantificadas ao longo do experimento, independentemente do grupo. No 13º dpi, os animais NT apresentaram 16.630,4 enquanto os TA 6.153,6 parasitos/ml de sangue (p<0,05). Os animais TAC foram os que tiveram a maior redução da carga parasitária em sangue e órgãos, muito embora também tenha havido redução nos animais TA (cérebro e coração) e TC (cérebro, coração, músculo e rim) em relação aos NT. Da fase aguda para a crônica houve redução da carga parasitária tanto em sangue quanto em órgãos (mais acentuada). Nos animais NT no 61º dpi, o sangue apresentou carga parasitária comparável a do coração, tecido adiposo, pulmão, intestino, baço e fígado, enquanto nos animais TAC o sangue foi o material biológico com a maior carga parasitária, confirmando que a parasitemia pode e deve ser utilizada para o diagnóstico e monitoramento da infecção por T. cruzi no organismo, em todas as fases da infecção. Ademais, o tecido adiposo atuaria como reservatório de T. cruzi no organismo, uma vez que a carga parasitária sofreu menor redução neste tecido após tratamento. A técnica de imunoistoquímica, realizada em amostras de tecido adiposo e cardíaco, confirmou os resultados da qPCR, fato importante especialmente no 61º dpi, quando as cargas parasitárias foram muito baixas. Portanto, o tratamento realizado em ambas as fases da infecção chagásica seria o mais eficaz para alcançar a redução da carga parasitária de T. cruzi no organismo, em relação ao tratamento realizado apenas uma vez. A qPCR, técnica extremamente sensível, poderia ser empregada para o monitoramento da parasitemia em pacientes tratados na fase crônica indeterminada, detectando falhas terapêuticas ou confirmando a cura etiológica. / The treatment of Chagas disease has been recommended in patients in the chronic indeterminate phase to reduce the parasite load, the development of clinical manifestations such as cardiomyopathies and episodes of reactivation. Serological methods are the gold standard for the definition of cure after treatment, but they do not evaluate the parasite load in tissues, and may take many years until reversion, while parasitological methods have low sensitivity in the chronic phase. In the present study, blood culture, optical microscopy, real-time PCR (qPCR) and immunohistochemistry were used to monitor the parasite load in blood and organs of Swiss mice infected with 2x103 forms of the T. cruzi Y strain. Untreated (NT) animals, treated only in the acute phase (TA), only in the chronic phase (TC) and in both phases of the infection (TAC) were analyzed. The treatment was performed with 100 mg/kg/day of benznidazole for 20 consecutive days. Samples were collected at the 13th dpi, 26th dpi and 61st dpi (peak of acute phase, end of acute phase and chronic phase). In the chronic phase of the infection, optical microscopy and blood culture found 0 and 25% of positive samples, respectively, and with qPCR the parasite load levels of all samples were quantified throughout the experiment, regardless of the group. At the 13th dpi, the NT animals presented 16,630.4 whereas the TA animals had 6,153.6 parasites/ml (p<0.05). TAC animals were the ones that had the greatest reduction of the parasite load in blood and organs, although there was also reduction in the TA (brain and heart) and TC (brain, heart, muscle and kidney) animals in relation to NT. From the acute phase to the chronic one there was reduction of the parasite load in both, blood and organs (more pronounced). In NT animals at the 61º dpi, blood samples presented parasite load levels comparable to that of the heart, adipose tissue, lung, intestine, spleen and liver, while in the TAC animals blood was the biological sample with the highest parasite load, confirming that parasitemia can and should be used for the diagnosis and monitoring of T. cruzi infection in the body at all stages of infection. In addition, the adipose tissue would act as reservoir of T. cruzi in the organism, since the parasite load suffered a smaller reduction in this tissue after treatment. The immunohistochemical technique, performed on adipose and cardiac tissues, confirmed the results of qPCR, an important fact especially in the 61º dpi, when parasite load levels were very low. Therefore, the treatment performed in both phases of the chagasic infection would be the most effective to achieve the reduction of parasite burden of T. cruzi in the organism, in comparison with the treatment performed only once. The qPCR, an extremely sensitive and timely technique, could be used to monitoring parasitemia in patients treated in the indeterminate chronic phase, detecting therapeutic failures or confirming the etiological cure.