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

The induction of sexual development in the planarian Dugesia tigrina (Girard).

Vowinckel, Christa. January 1968 (has links)
No description available.
2

The induction of sexual development in the planarian Dugesia tigrina (Girard).

Vowinckel, Christa. January 1968 (has links)
No description available.
3

Desenvolvimento de mudas de bromélias em resíduos orgânicos e industriais / Development of seedlings of bromeliads in organic and industrial waste

Rocha, Ariane Borges de Figueiredo 04 June 2012 (has links)
Made available in DSpace on 2016-05-02T13:55:35Z (GMT). No. of bitstreams: 1 Ariane BorgesdeFigueiredoRocha-dissertacao.pdf: 220565 bytes, checksum: c0a3d2c9d3654e8b2e547557ee3aa684 (MD5) Previous issue date: 2012-06-04 / Bromeliads are commonly used for ornamental and landscaping purposes, and there is a lack of knowledge about farming techniques and ideal substrate, leading to extractive exploitation of these species in their natural habitat. Thus, proposals for reuse of these wastes can solve problems of contamination of the environment and simultaneously serve as soil conditioner. The objective of this study was to evaluate the development of seedlings of the bromeliad Neoregelia tigrina (Ruschi) in organic and industrial waste. The treatments were: 100% solid organic waste; 100% pine bark; 100% coconut fiber; 75% coir and 25% waste; 50% coir and 50% waste; 25% coconut fiber and 75% waste; 75% pine bark and 25% waste; 50% pine bark and 50% waste; 25% pine bark and 75% residue. The statistical design was completely randomized (CRD) with three replications and three plants per plot. Statistical analyzes show significance by the Scott Knott test (p <0.05). As alternative substrates the pine bark and coconut fiber substrates stood out statistically for having low cost and easy accessibility for ornamental producers. Pure waste should not be used to produce bromeliads. Bromeliad seedlings of Neogerelia tigrina (Ruschi), when grown in substrates containing 100% pine bark, showed the best results on the number of leaves, shoot growth, fresh shoot weight, root length and root dry mass. / As bromélias são comumente utilizadas para uso paisagístico e ornamentação e há um desconhecimento de técnicas de cultivo e substrato ideal, levando à exploração extrativista dessas espécies no seu habitat natural. Com isso, propostas de reutilização desses resíduos podem resolver problemas de contaminação do meio ambiente e ao mesmo tempo servir como condicionadores de solo. Objetivou-se com este trabalho avaliar o desenvolvimento de mudas de bromélias da espécie Neoregelia tigrina (Ruschi) em resíduos orgânicos e industriais. Os tratamentos utilizados foram: 100% de resíduo orgânico sólido; 100% de casca de pinus; 100% de fibra de coco; 75% de fibra de coco e 25% resíduo; 50% fibra de coco e 50% resíduo; 25% fibra de coco e 75% resíduo; 75% de casca de pinus e 25% resíduo; 50% casca de pinus e 50% resíduo; 25% casca de pinus e 75% resíduo. O delineamento estatístico foi inteiramente casualizado (DIC), com 3 repetições e 3 plantas por parcela. As análises estatísticas apresentam significância pelo teste de Scott Knott (p< 0,05). Como substratos alternativos sobressaíram-se estatisticamente a casca de pinus e a fibra de coco, substratos que apresentam baixo custo financeiro e fácil acessibilidade pelos produtores ornamentais. Não se deve utilizar resíduo puro para produção de bromélias e as mudas de bromélias Neogerelia tigrina (Ruschi) quando desenvolvidas em substratos contendo 100% casca de pinus apresentaram os melhores resultados quanto ao número de folhas, crescimento da parte aérea, massa fresca da parte aérea, comprimento do sistema radicular e massa seca do sistema radicular.
4

Caracterização da biologia de populações de planárias do gênero Giradia nativas do Rio Grande do Sul

Knakievicz, Tanise January 2007 (has links)
As planárias são organismos de escolha para a realização de uma ampla gama de estudos básicos, abrangendo desde aspectos ecotoxicológicos até abordagens de biologia celular e molecular. Isso se deve, especialmente, à capacidade extraordinária de regeneração desses organismos e à presença de células-tronco somáticas (neoblastos) no adulto. Portanto, a disponibilização de espécies e linhagens de planárias com características fisiológicas bem definidas é fundamental. As espécies Girardia tigrina e Girardia schubarti, nativas do Rio Grande do Sul, foram estudadas quanto ao modo de reprodução, ciclo de vida, capacidade de regeneração e à suscetibilidade a agentes tóxicos e mutagênicos. Em ambas as espécies, o modo de reprodução correlaciona-se com a ploidia; indivíduos diplóides são geralmente sexuados, e os indivíduos triplóides e mixoplóides são exclusivamente fissiparitários. Planárias fissiparitárias geram um número menor de descentes e são mais longevas do que as sexuadas. A freqüência de reprodução sexuada e a longevidade em ambas as espécies sofrem influência das condições ambientais, mas alterações no ambiente não levam a trocas entre os modos de reprodução sexuada e assexuada. G. tigrina e G. schubarti apresentam capacidades similares de regeneração e suscetibilidades a agentes clastogênicos. Assim, ambas as espécies permitem avaliações da toxicidade aguda e/ou crônica de amostras de interesse através de bioensaios de mortalidade/mobilidade, de regeneração, de micronúcleos e de reprodução. Tais ensaios foram padronizados para a avaliação dos efeitos da exposição de G. tigrina a soluções de sulfato de cobre. Portanto, este trabalho disponibilizou um sistema padronizado de bioensaios rápidos, sensíveis e baratos para biomonitoramento ambiental dos ecossistemas de água doce. Além disso, os resultados obtidos forneceram subsídios para estudos dos mecanismos de manutenção de neoblastos, os quais são diretamente responsáveis pela regeneração, pela homeostase dos tecidos e pela reprodução. / Planarians are choice organisms used in a wide series of basic studies including both ecotoxicology aspects and cellular and molecular approach. It is especially due to its extraordinary regeneration capacity and to the presence of somatic stem cell (neoblasts) in adult organisms. Therefore, the availability of species and lineage with well known physiological characteristics is fundamental. The species Girardia tigrina e Girardia schubarti, native from Rio Grande do Sul State, Brazil, were studied as to the reproductive modes, life cycle, regenerative capacity and toxicity, and susceptibility to teratogenic and mutagenic agents. In both species, there was inter-relation between reproductive mode and ploidy. Diploid individuals were usually sexual and triploid, and mixoploid individuals were exclusively fissiparous. Fissiparous planarians produce smaller number of descendents, and show longer lifespan than sexual planarians. In both species the reproduction sexual frequency and the longevity undergo influence of the environmental conditions; nevertheless, environmental changes do not lead to the switching from sexual to asexual reproduction. G. tigrina and G. schubarti species show similar regeneration capacity and clastogenic agent susceptibility. Thus, both species allow assessment of acute and/or chronic toxicity of choice samples by lethality/mobility, regeneration, micronuclei, and reproduction bioassays. Such assays were standardized for assessment of effects of G. tigrina exposure to copper sulfate solutions. In addition, this work provided a rapid, sensitive and expensive standardized bioassay system for environmental biomonitoring of freshwater ecosystems, based on native organisms from Rio Grande do Sul State. Besides, the obtained results provide bases for further studies on the neoblast maintenance mechanisms, which are directly responsible for regeneration, homeostasis of all tissue and reproduction.
5

Caracterização da biologia de populações de planárias do gênero Giradia nativas do Rio Grande do Sul

Knakievicz, Tanise January 2007 (has links)
As planárias são organismos de escolha para a realização de uma ampla gama de estudos básicos, abrangendo desde aspectos ecotoxicológicos até abordagens de biologia celular e molecular. Isso se deve, especialmente, à capacidade extraordinária de regeneração desses organismos e à presença de células-tronco somáticas (neoblastos) no adulto. Portanto, a disponibilização de espécies e linhagens de planárias com características fisiológicas bem definidas é fundamental. As espécies Girardia tigrina e Girardia schubarti, nativas do Rio Grande do Sul, foram estudadas quanto ao modo de reprodução, ciclo de vida, capacidade de regeneração e à suscetibilidade a agentes tóxicos e mutagênicos. Em ambas as espécies, o modo de reprodução correlaciona-se com a ploidia; indivíduos diplóides são geralmente sexuados, e os indivíduos triplóides e mixoplóides são exclusivamente fissiparitários. Planárias fissiparitárias geram um número menor de descentes e são mais longevas do que as sexuadas. A freqüência de reprodução sexuada e a longevidade em ambas as espécies sofrem influência das condições ambientais, mas alterações no ambiente não levam a trocas entre os modos de reprodução sexuada e assexuada. G. tigrina e G. schubarti apresentam capacidades similares de regeneração e suscetibilidades a agentes clastogênicos. Assim, ambas as espécies permitem avaliações da toxicidade aguda e/ou crônica de amostras de interesse através de bioensaios de mortalidade/mobilidade, de regeneração, de micronúcleos e de reprodução. Tais ensaios foram padronizados para a avaliação dos efeitos da exposição de G. tigrina a soluções de sulfato de cobre. Portanto, este trabalho disponibilizou um sistema padronizado de bioensaios rápidos, sensíveis e baratos para biomonitoramento ambiental dos ecossistemas de água doce. Além disso, os resultados obtidos forneceram subsídios para estudos dos mecanismos de manutenção de neoblastos, os quais são diretamente responsáveis pela regeneração, pela homeostase dos tecidos e pela reprodução. / Planarians are choice organisms used in a wide series of basic studies including both ecotoxicology aspects and cellular and molecular approach. It is especially due to its extraordinary regeneration capacity and to the presence of somatic stem cell (neoblasts) in adult organisms. Therefore, the availability of species and lineage with well known physiological characteristics is fundamental. The species Girardia tigrina e Girardia schubarti, native from Rio Grande do Sul State, Brazil, were studied as to the reproductive modes, life cycle, regenerative capacity and toxicity, and susceptibility to teratogenic and mutagenic agents. In both species, there was inter-relation between reproductive mode and ploidy. Diploid individuals were usually sexual and triploid, and mixoploid individuals were exclusively fissiparous. Fissiparous planarians produce smaller number of descendents, and show longer lifespan than sexual planarians. In both species the reproduction sexual frequency and the longevity undergo influence of the environmental conditions; nevertheless, environmental changes do not lead to the switching from sexual to asexual reproduction. G. tigrina and G. schubarti species show similar regeneration capacity and clastogenic agent susceptibility. Thus, both species allow assessment of acute and/or chronic toxicity of choice samples by lethality/mobility, regeneration, micronuclei, and reproduction bioassays. Such assays were standardized for assessment of effects of G. tigrina exposure to copper sulfate solutions. In addition, this work provided a rapid, sensitive and expensive standardized bioassay system for environmental biomonitoring of freshwater ecosystems, based on native organisms from Rio Grande do Sul State. Besides, the obtained results provide bases for further studies on the neoblast maintenance mechanisms, which are directly responsible for regeneration, homeostasis of all tissue and reproduction.
6

Caracterização da biologia de populações de planárias do gênero Giradia nativas do Rio Grande do Sul

Knakievicz, Tanise January 2007 (has links)
As planárias são organismos de escolha para a realização de uma ampla gama de estudos básicos, abrangendo desde aspectos ecotoxicológicos até abordagens de biologia celular e molecular. Isso se deve, especialmente, à capacidade extraordinária de regeneração desses organismos e à presença de células-tronco somáticas (neoblastos) no adulto. Portanto, a disponibilização de espécies e linhagens de planárias com características fisiológicas bem definidas é fundamental. As espécies Girardia tigrina e Girardia schubarti, nativas do Rio Grande do Sul, foram estudadas quanto ao modo de reprodução, ciclo de vida, capacidade de regeneração e à suscetibilidade a agentes tóxicos e mutagênicos. Em ambas as espécies, o modo de reprodução correlaciona-se com a ploidia; indivíduos diplóides são geralmente sexuados, e os indivíduos triplóides e mixoplóides são exclusivamente fissiparitários. Planárias fissiparitárias geram um número menor de descentes e são mais longevas do que as sexuadas. A freqüência de reprodução sexuada e a longevidade em ambas as espécies sofrem influência das condições ambientais, mas alterações no ambiente não levam a trocas entre os modos de reprodução sexuada e assexuada. G. tigrina e G. schubarti apresentam capacidades similares de regeneração e suscetibilidades a agentes clastogênicos. Assim, ambas as espécies permitem avaliações da toxicidade aguda e/ou crônica de amostras de interesse através de bioensaios de mortalidade/mobilidade, de regeneração, de micronúcleos e de reprodução. Tais ensaios foram padronizados para a avaliação dos efeitos da exposição de G. tigrina a soluções de sulfato de cobre. Portanto, este trabalho disponibilizou um sistema padronizado de bioensaios rápidos, sensíveis e baratos para biomonitoramento ambiental dos ecossistemas de água doce. Além disso, os resultados obtidos forneceram subsídios para estudos dos mecanismos de manutenção de neoblastos, os quais são diretamente responsáveis pela regeneração, pela homeostase dos tecidos e pela reprodução. / Planarians are choice organisms used in a wide series of basic studies including both ecotoxicology aspects and cellular and molecular approach. It is especially due to its extraordinary regeneration capacity and to the presence of somatic stem cell (neoblasts) in adult organisms. Therefore, the availability of species and lineage with well known physiological characteristics is fundamental. The species Girardia tigrina e Girardia schubarti, native from Rio Grande do Sul State, Brazil, were studied as to the reproductive modes, life cycle, regenerative capacity and toxicity, and susceptibility to teratogenic and mutagenic agents. In both species, there was inter-relation between reproductive mode and ploidy. Diploid individuals were usually sexual and triploid, and mixoploid individuals were exclusively fissiparous. Fissiparous planarians produce smaller number of descendents, and show longer lifespan than sexual planarians. In both species the reproduction sexual frequency and the longevity undergo influence of the environmental conditions; nevertheless, environmental changes do not lead to the switching from sexual to asexual reproduction. G. tigrina and G. schubarti species show similar regeneration capacity and clastogenic agent susceptibility. Thus, both species allow assessment of acute and/or chronic toxicity of choice samples by lethality/mobility, regeneration, micronuclei, and reproduction bioassays. Such assays were standardized for assessment of effects of G. tigrina exposure to copper sulfate solutions. In addition, this work provided a rapid, sensitive and expensive standardized bioassay system for environmental biomonitoring of freshwater ecosystems, based on native organisms from Rio Grande do Sul State. Besides, the obtained results provide bases for further studies on the neoblast maintenance mechanisms, which are directly responsible for regeneration, homeostasis of all tissue and reproduction.
7

Výskyt a ekologie ploštěnky americké (Dugesia tigrina) ve Vltavě a vybraných pražských potocích a její interakce s původními druhy ploštěnek / Distribution and ecology of the turbellarian Dugesia tigrina in the Vltava river and selected Prague brooks and its interactions with native turbellarian species

Sevruková, Natálie January 2011 (has links)
Key words: (Dugesia tigrina), ecology, bioindication, predation, Vltava, Prague The main goal of my thesis was the research of occurrence and ecology of planarians of the group Ttricladida in the Vltava River and some brooks flowing through the territory of Prague. The emphasis was given on the non-native North American species - Dugesia tigrina. The research can be divided into field surveys of population size and ecological requirements of planarians and a laboratory experiment, in which I have investigated the predation behavior of planarians. During my fieldwork, which took place from August 22th to November 11th 2009, I have found out that the Dugesia tigrina occurs only in the Vltava river, in six of the nine studied localities. During the research it was not found in the studied brooks. It chooses localities with a natural shoreline, deeper ground, rapid water and it lives in company of mainly Dugesia polychroa. It appeared at moderately polluted places. During the predation experiment, which ran from December 17th 2009 to October 20th 2010 at a temperature of 14 řC and triple repetitions in all mutual combinations of five planarian species, intraspecific cannibalism and frequent asexual reproduction of Dugesia tigrina was comfirmed. The experiment showed mainly preying of indigenous...
8

Resource partitioning in a viverrid assemblage.

Maddock, Anthony Hamilton. 03 July 2014 (has links)
Viverrids are small carnivores that achieve high species richness throughout their range. This study investigated the ecology and resource partitioning of five members of this family (Genetta tigrina, Herpestes ichneumon, Galerella sanguinea, Atilax paludinosus and Mungos mungo) that coexist in Vernon Crookes Nature Reserve on the south coast of Natal, South Africa. Emphasis was placed on differences and similarities within this assemblage. Diets of the viverrids were determined by scat analysis and prey abundance was revealed by means of a monthly trapping programme. The spatial ecology of the assemblage was assessed using radio-tracking and habitat utilisation was compared with habitat availability. The activity regimens of viverrids were also determined from radio-tracking. Consideration of all three major niche dimensions (food, habitat and time) revealed important differences within this assemblage. Each species used different resources, along at least one niche axis, from other members in the assemblage. Consequently, the three niche dimensions segregated all five species. These differences may reduce interactions and facilitate coexistence. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1988.
9

The Effect of Caffeine and Ethanol on Flatworm Regeneration.

Collins, Erica Leighanne 14 August 2007 (has links) (PDF)
Flatworms, or planarian, have a high potential for regeneration and have been used as a model to investigate regeneration and stem cell biology for over a century. Chemicals, temperature, and seasonal factors can influence planarian regeneration. Caffeine and ethanol are two widely used drugs and their effect on flatworm regeneration was evaluated in this experiment. Non-toxic levels of caffeine, a stimulant, and ethanol, a depressant, were determined. The tails of the flatworms were removed and the regeneration stage was analyzed every 3 days for 15 days to see the effect of these drugs alone and in combination on regeneration. For day 3 and day 6, there was a significant difference between the ethanol treatment and the other treatments (positive control, caffeine treatment, and combined treatment). The ethanol treatment showed a delay in the initiation of regeneration but caught up to the other treatments by day 15.
10

The Effects of Cannabinoids on Regeneration Rates and Potential Matrix Metalloproteinase and Collagenase Levels in Planaria (Dugesia tigrina)

Blasiman, Julia L. 23 December 2013 (has links)
No description available.

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