Made available in DSpace on 2014-10-09T12:33:07Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:17Z (GMT). No. of bitstreams: 0 / Triclosan é um composto orgânico de baixa solubilidade que vem sendo utilizado em formulações de cremes dentais e faciais, xampu, sabonetes, embalagens de gêneros alimentícios e diversos tipos de materiais, tais como, adesivos, brinquedos, sapatos, selantes, tintas, colchão, roupas, pisos, toldos e rejuntes. O amplo uso deste composto deve-se à grande eficácia contra bactérias Gram negativas e Gram positivas. Por seu extenso uso, evidências da presença de Triclosan têm sido frequentemente relatadas em efluentes urbanos e industriais, águas superficiais e sedimentos de ambientes dulcícolas, estuarinos e marinhos, como também em organismos aquáticos como algas, peixes e mamíferos. Neste contexto, o presente estudo avaliou a toxicidade aguda e crônica de Triclosan para diferentes invertebrados marinhos de águas tropicais. Para tanto, ensaios de toxicidade aguda foram realizados com o copépodo Nitokra sp (mortalidade) e com o ouriço-do-mar Lytechinus variegatus (taxa de fertilização). Para a avaliação do efeito crônico, ensaios de toxicidade de curta duração (desenvolvimento embriolarval) foram realizados com o ouriço-do-mar L. variegatus e Perna perna. Além desses métodos, o ensaio do Tempo de Retenção do Corante Vermelho Neutro foi empregado com a finalidade de se avaliar os efeitos do Triclosan sobre a estabilidade da membrana lisossômica de hemócitos de P. perna. Na avaliação do efeito agudo, o valor médio da CL(I)50;96h encontrada para o copépodo foi de 0,20 mg.L-1 enquanto que o valor médio da CI(I)50;1h para ouriço-do-mar foi de 0,28 mg.L-1. Já na avaliação do efeito crônico, o valor médio da CI(I)50;24h para ouriço-do-mar foi de 0,14 mg.L-1 e para o molusco bivalve a média da CI(I)50;48h, foi de 0,13 mg.L-1. O efeito na estabilidade da membrana lisossômica de hemócitos de P. perna ocorreu em concentrações a partir de 12 ng.L-1. Estes resultados evidenciam o risco ecológico da introdução contínua desse composto em ambientes marinhos, e devem ser considerados para identificação de concentrações seguras e futura regulação do bactericida Triclosan na legislação ambiental nacional e internacional. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Phenotypic variation manifests from either simple (monogenic) or complex (multigenic) traits. Variation due to genetic and environmental influences is important because the ability to produce a range of phenotypes is essential for adaptive evolution. Complex traits are important not only for evolution, but because many diseases are complex traits. The genetic architecture of complex traits can be very multifaceted, with a large number of causal genes each having a small effect on the overall heritability of the trait, and as such our understanding of the genetic architecture and control of complex traits is limited. Complex traits are studied through quantitative trait loci mapping and genome-wide association studies. Since there are a great range of resources available for the nematode Caenorhabditis elegans, this is an appropriate system in which to study the genetic architecture of complex traits. Dauer larvae development represents a suitable complex trait as many of the genes involved and their genetic pathways have been identified. This trait is also important for the clear links between the dauer larvae of free-living species and the infective stages of many parasitic nematodes, and is therefore important as a model complex trait. Dauer larvae are routinely studied under unnatural conditions, with a cohort of aged-matched worms exposed to concentrated pheromone from many worms, conditions that are not obviously ecologically or evolutionally relevant. It is therefore important to understand the dynamics of growing populations in the laboratory both specifically to understand C. elegans, and generally to understand the genetics of complex traits. Methods have been established for the analysis of population growth assays, and experiments to validate this style of assay have been carried out for the analysis of dauer larvae development in a growing population. In this, extensive variation in dauer larvae development between natural wild isolates and the canonical isolate N2 has been shown, variation which has previously not been demonstrated in standard dauer larvae assays. The genetic basis of this variation was also investigated using two Recombinant Inbred Line (RILs) panels made from two distinct parental genotypes of C. elegans, Isogenic Lines (ILs) of C. elegans and also a C. briggsae RIL panel. These analyses revealed that the genetic architecture of dauer larvae development in growing populations is highly complex, with a large number of QTLs affecting this trait. Also, comparison of the results from the different mapping approaches (RILs vs. ILs) revealed variation in their power to detect QTLs, as the ILs were capable of identifying far more QTLs than the RILs. Three candidate genes which have an effect on dauer larvae development in growing populations were identified and analysed. These candidates are npr-1, srg-36 and srg-37, each showing a negative effect on dauer larvae development in a growing population and an allelic effect of variation at npr-1. Together, these results demonstrate that extensive variation in dauer larvae development can be analysed in growing populations, that the underlying genetics can be mapped and that candidate genes can be identified for the underlying regions.

In this study macro-invertebrates were sampled quantitatively in 10 lowland vegetation communities on Marion Island over a one-year period commencing in May 1996 as part of a larger investigation into the distribution, abundance and species energy use of invertebrates across an altitudinal transect on Marion Island. The data collected for this particular study were used to investigate the habitat specificity and seasonality of the macro-invertebrates, as well as the impact of alien species on the local community. As part of the latter study a watching brief for alien species was kept throughout the field year and the alien species list was updated accordingly. The quantitative data were also used to compare changes in the density and biomass of selected macro-invertebrate species between 1976/77 and 1996/97 by reworking the data on macro-invertebrates collected by Alan Burger in 1976/77 during the course of his work on the Lesser Sheathbill. In the current study it was found that the majority of the macro-invertebrate species are not particularly habitat specific. Rather, they generally prefer either moist mire habitats, or the more well-drained non-mire vegetation complexes. In addition, many of the species had pronounced peaks in abundance in a given season (winter, summer, autumn and spring peaks were recorded), although this seasonality varied between species and between habitats for a given species. Although this finding does not support previous generalizations concerning an absence of seasonality in sub-Antarctic invertebrates, it does show that sub-Antarctic invertebrates, like their Antarctic counterparts, may have extremely flexible life history strategies. Limnophyes minimus was found to be one of the most abundant alien species on the island, and reached high densities in most of the plant communities sampled, with the highest density being recorded in the Cotula plumosa biotically influenced community (annual mean of 4365 individuals.m-2 ) and the lowest in the Crassula moschata salt spray community (annual mean of 41 individuals.m-2 ). Estimates of litter ingestion indicated that L. minimus larvae are capable of consuming between 0.07 and 8.54 g(dry mass)·m-2 per year, depending on the community. In some communities this litter consumption amounted to an order of magnitude more than that consumed by Pringleophaga marioni (Lepidoptera, Tineidae). Although the larvae of this moth species are thought to represent the bottleneck to nutrient recycling on the island, this study showed that midge larvae may also contribute substantially to this process. As a consequence, the considerable changes that have been predicted to occur in Marion Island's terrestrial ecosystem as a consequence of enhanced predation by mice on P. marioni larvae, may be retarded or obscured by the contribution of the midge larvae to nutrient cycling. Hence, it is suggested that greater attention be given to the small and inconspicuous elements of the alien sub-Antarctic faunas because such species may have profound consequences for ecosystem functioning on these islands. The likely impact of alien species on the terrestrial macro-invertebrates, and the communities they belong to, was further highlighted by the dramatic decline in the biomasses of the macro-invertebrates between 1976/77 and 1996/97. Significant declines in biomass of between 83-97% were found for Lepidoptera larvae (mostly Pringleophaga marioni) and for weevils, the major prey species of the introduced house mouse between 1976/77 and 1996/97, although non-prey species appear to have shown either no changes (the indigenous snail Notodicus hookeri) or increases in abundance (the introduced slug Deroceras caruanae). However, differences in sampling strategies adopted by these two studies and others investigating macro-invertebrate abundances mean that the current results may well be underestimates of change, while other studies must be interpreted with considerable caution. Nonetheless, the current findings and those of authors suggest that mice may be having pronounced impacts on the terrestrial ecosystem at Marion Island. In sum, the findings of this thesis indicate that considerably more attention must be given to well-planned collaborative work to address critically important management questions, identified by the Prince Edward Island Management Committee, and that considerable care must be taken to prevent the further introduction of alien species to sub-Antarctic islands. Copyright / Dissertation (MSc)--University of Pretoria, 2010. / Zoology and Entomology / unrestricted

The relative sensitivities of four benthic invertebrates (𝘏𝘺𝘢𝘭𝘦𝘭𝘭𝘢 𝘢𝘻𝘵𝘦𝘤𝘢, 𝘊𝘩𝘪𝘳𝘰𝘯𝘰𝘮𝘶𝘴 𝘳𝘪𝘱𝘢𝘳𝘪𝘶𝘴, 𝘏𝘦𝘹𝘢𝘨𝘦𝘯𝘪𝘢 spp., and 𝘛𝘶𝘣𝘪𝘧𝘦𝘹 𝘵𝘶𝘣𝘪𝘧𝘦𝘹) were determined separately for cadmium, copper, and nickel in 96-hour water-only and in spiked sediment exposures. Survival (LC25's and LC5O's), growth and reproduction (IC25's) endpoints were compared amongst the four species. In the water-only tests, 𝘏. 𝘢𝘻𝘵𝘦𝘤𝘢 is the most sensitive species to cadmium and nickel, with mean LC5O's of 0.013 and 3.6 mg/L respectively, and 𝘊. 𝘳𝘪𝘱𝘢𝘳𝘪𝘶𝘴 is the most sensitive species to copper, with a mean LC5O of 0.043 mg/L. In the spiked sediment exposures, 𝘏𝘦𝘹𝘢𝘨𝘦𝘯𝘪𝘢 spp. is most sensitive species to copper with a mean LC5O in sediment of 93 μg/g and a mean IC25 of 38 μg/g, and 𝘏. 𝘢𝘻𝘵𝘦𝘤𝘢 is most sensitive species to cadmium and nickel, with mean LC5O's of 33 and 67 μg/g respectively and mean IC25's of 10 and 40 μg/g respectively. Overall, 𝘛. 𝘵𝘶𝘣𝘪𝘧𝘦𝘹 is the least sensitive species to all metals tested, and the number of young produced/adult is the most sensitive of the reproduction endpoints for 𝘛. 𝘵𝘶𝘣𝘪𝘧𝘦𝘹. The relative sensitivities reveal that two endpoints, 𝘊𝘩𝘪𝘳𝘰𝘯𝘰𝘮𝘶𝘴 and 𝘏𝘦𝘹𝘢𝘨𝘦𝘯𝘪𝘢 survival, can be used to possibly distinguish between cadmium, copper, and nickel metal toxicity. Species test responses in field-collected sediments from areas contaminated primarily by the above mentioned metals were compared to the determined sensitivities in order to establish the causative agent of toxicity. Sediment toxicity was categorized first by comparing species responses to those established for a reference database. Responses in the field sediment support suspected toxicant in some cases, but not others. Multivariate analyses were used to assess sediment toxicity in the field sites based on the species responses, and these analyses reveal that the test endpoints respond to different environmental variables in ordination space. A comparison of test responses in the field sites to those in reference sites in ordination space reveals 13 of the 15 field-collected sites to be toxic or severely toxic. / Thesis / Master of Science (MS)

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2004. / Thesis documentation sheet inserted. Appendix reproduces three papers and manuscripts co-authored with R.K. Johnson and two papers co-authored with R.K. Johnson and L. Sandin. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; online version lacks appendix.

Thesis (Ph. D.)--University of Tartu, 2004. / Includes reprint of 6 previously published articles. Includes bibliographical references.

Riparian buffers along stream margins have been widely adopted as a management strategy to mitigate the adverse effects of plantation forestry on stream ecosystems. However, the efficacy of these riparian buffers can be jeopardised by variations in width, length, and vegetation which can range from native and exotic scrub (including bracken, gorse, broom and blackberry) to remnant beech forest. This thesis investigates the influence of riparian vegetation age and composition, on stream ecosystems within exotic pine plantations. Initially, a survey of 50 streams within pine forests of various ages and riparian composition was conducted at sites from mid-Canterbury to Hanmer Springs over the summer of 2004-2005. Additionally, terrestrial subsidies were compared between young pine, mature pine and indigenous forest streams to ascertain differences or similarities between vegetation types. A range of physico-chemical and biological characteristics were recorded, while vegetative age and composition with catchment, riparian buffer and reach scales were determined using GIS. Forestry activities were found to vary temporarily and tended to adversely impact upon streams where riparian buffers were narrow and lacked indigenous vegetation. Stream instability and sedimentation were consistently higher in catchments lacking indigenous riparian vegetation, and more markedly so in recently harvested catchments compared with more mature forests. Streams dominated by pine forests had finer substrates with higher water temperatures and levels of turbidity, while those dominated by indigenous forest had coarser substrates, higher flows and dissolved oxygen levels, and less in-stream debris. Benthic community composition was similar among sites, although taxonomic richness, EPT diversity, and invertebrate abundances were enhanced by indigenous riparian vegetation.

Invertebrates are suffering the greatest species loss in the current biodiversity crisis. These animals perform essential ecosystem functions upon which humanity depends yet they are largely ignored m conservation efforts. The main challenges facing invertebrate conservationists, in terms of raising public awareness, are to change common negative perceptions regarding invertebrates and to apply some form of value to them. Conservation efforts can be improved by raising public awareness of, and appreciation for, invertebrates in the context of ecotourism. Current levels of inclusion of invertebrates in ecotourism activities were gauged, using qualitative research methods of participant observation and semi-structured interviews. The response of tourists to the concept of the inclusion of both western/scientific and indigenous knowledge regarding invertebrates into current and planned ecotourism activities was determined using the quantitative research method of a structured questionnaire. Canvassing of tourists was done at a popular ecotourism destination (Hluhluwe-Umfolozi Nature Reserve) and 121 questionnaires were completed. In addition to tourists the opinions and attitudes of a range of people working in ecotourism and conservation were examined via semi-structured interviews. The respondents were specifically selected according to the positions they held in the ecotourism and conservation field and a total of eight people in management, ten ecotourism guides and seven ecotourism trainers were interviewed. The findings revealed that there is currently negligible information regarding invertebrates in ecotourism activities. There was an overwhelmingly positive response from tourists, with 95% indicating that they would like to see information regarding invertebrates included in ecotourism activities. Ecotourism service providers, such as tour guides and those in conservation management also indicated a positive attitude toward the concept. There is thus potential to increase levels of information regarding invertebrates in ecotourism and it is recommended that ecotourism include a focus on invertebrates. Recommendations on how to address the lack of invertebrate information in ecotourism are provided and examples of the types of invertebrates to include in specific ecotourism activities are given. Including a focus on invertebrates in ecotourism will serve the multiple purposes of placing value on invertebrates; raising public awareness and hence the conservation status of invertebrates, and finally will increase the scope of ecotourism. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

Flight at high altitude is part of a migration strategy that maximises insect population displacement. This thesis represents the first substantial analysis of insect migration and layering in Europe. Vertical-looking entomological radar has revealed specific characteristics of high-altitude flight: in particular layering (where a large proportion of the migrating insects are concentrated in a narrow altitude band). The meteorological mechanisms underpinning the formation of these layers are the focus of this thesis. Aerial netting samples and radar data revealed four distinct periods of high-altitude insect migration: dawn, daytime, dusk, and night-time. The most frequently observed nocturnal profiles during the summertime were layers. It is hypothesised that nocturnal layers initiate at a critical altitude (200–500 m above ground level) and time (20:00–22:00 hours UTC). Case study analysis, statistical analysis, and a Lagrangian trajectory model showed that nocturnal insect layers probably result from the insects’ response to meteorological conditions. Temperature was the variable most correlated with nocturnal insect layer presence and intensity because insects are poikilothermic, and temperatures experienced during high-altitude migration in temperate climates are expected to be marginal for many insects’ flight. Hierarchical effects were detected such that other variables—specifically wind speed—were only correlated with insect layer presence and intensity once temperatures were warm. The trajectory model developed comprised: (i) insect flight characteristics; (ii) turbulent winds (which cause vertical spread of the layer); and (iii) mean wind speed, which normally leads to horizontal displacements of hundreds of kilometres in a single migratory flight. This thesis has revealed that there is considerable migratory activity over the UK in the summer months, and a range of fascinating phenomena can be observed (including layers). The UK has moved from one of the least studied to perhaps the best studied environments of aerial insect migration and layering in the world.

Aggregation of the abundant neural protein α-synuclein contributes to cellular toxicity in Parkinson‘s disease. We have created transgenic nematodes carrying fusion constructs encoding human α-synuclein (S) tagged with YFP (V) and/or CFP (C) as a fluorescent marker. Using the unc-54 myosin promoter, a synuclein-YFP (unc-54::SV (NI)) fusion construct was abundantly expressed in the body wall muscles of Caenorhabditis elegans. Permanent integrated lines were successfully generated for unc-54::V (NI), unc-54::S+V (I), unc-54::SC+SV (I), unc-54::C+V (I), and unc-54::CV (I) using gamma irradiation. The outcrossed transgenic synuclein strains were radiation sensitive and have shorter life span and lower pharyngeal pumping compared to wild type N2 and unc-54::V (I) worms. Fluorescence Resonance Energy Transfer (FRET) was measured for all the transgenic strains. The unc-54::SC+SV (I) worms showed FRET signals intermediate between the negative (unc-54::C+V (I)) and positive (unc-54::CV (I)) control strains. Confocal images were taken to confirm the presence of FRET. FRET signals increase markedly during early adult life in unc-54::SC+SV (I) worms. RNA interference by feeding was performed in unc-54::SC+SV (I) worms to knock out the Hip-1 co-chaperone function, thereby increasing the FRET signal. unc-54::SC+SV (I) fusion worms were also exposed to pesticides such as chlorpyrifos and rotenone, and we observed an increase in the size and intensity of fluorescent aggregates thereby increasing the FRET signal. Finally we have quantified reactive oxygen species (ROS) for unc-54::SC+SV (I) fusion worms and NL5901 strains by using the H2DCF-DA assay, showing that ROS levels were increased by pesticide exposure.