• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 24
  • 11
  • 7
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 54
  • 12
  • 10
  • 9
  • 6
  • 6
  • 5
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 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.
31

Characterisation of the NADH dehydrogenases associated with isolated plant mitochondria / Kathleen Lydia Soole

Soole, Kathleen Lydia January 1989 (has links)
Typescript (Photocopy) / Bibliography: leaves i-xii. (3rd paging sequence) / x, 157, xii, 13 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Botany, 1990
32

Opines in crown gall and hairy root diseases / by Maarten Harm Ryder

Ryder, Maarten Harm January 1984 (has links)
Bibliography: leaves 125-140 / x, 140, [50] leaves, [3] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agricultural Biochemistry, 1984
33

Inositol phosphate generation in the heart : mechanisms and functional relevance

Matkovich, Scot J. Unknown Date (has links) (PDF)
The studies described in this thesis have used principally the rat neonatal cardiomyocyte (NCM) model to investigate previously unresolved questions regarding inositol phosphate signalling in the heart. Inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) is known to be an arrhythmogenic molecule in the setting of cardiacischaemia and subsequent reperfusion, but the mechanisms responsible for its enhanced generation in pathological circumstances, as well as those suppressing its generation during phospholipase C (PLC)-coupled receptor stimulation under physiological conditions, have not been characterised. [3H]Inositol-labelling in combination with anion-exchange high performance liquid chromatography (HPLC)was used to gain an accurate picture of the changes in various [3H]InsP isomers induced by PLC stimulation.
34

Spatially and temporally resolved delivery of stimuli to single cells using nanocapsules and laser manipulation /

Sun, Bingyun. January 2005 (has links)
Thesis (Ph. D.)-- University of Washington, 2005. / Vita. Includes bibliographical references (leaves 108-114).
35

Hindrance of the Myosin Power Stroke Posed by the Proximity to the Troponin Complex Identified Using a Novel LRET Fluorescent Nanocircuit

Coffee Castro-Zena, Pilar G. 05 1900 (has links)
A novel luminescence resonance energy transfer (LRET) nanocircuit assay involving a donor and two acceptors in tandem was developed to study the dynamic interaction of skeletal muscle contraction proteins. The donor transmits energy relayed to the acceptors distinguishing myosin subfragment-1 (S1) lever arm orientations. The last acceptor allows the detection of S1's bound near or in between troponin complexes on the thin filament. Additionally, calcium related changes between troponin T and myosin were detected. Based on this data, the troponin complex situated every 7 actin monomers, hinders adjacently bound myosins to complete their power stroke; whereas myosins bound in between troponin complexes undergo complete power strokes.
36

Vývoj ultrastrukturálních metod a jejich použití pro studium buěčnénho jádra / Development of ultrastructural methods and their application in studies on the cell nucleus

Filimonenko, Anatoly January 2014 (has links)
Despite the capabilities of molecular-biological methods in deciphering the interplay of different biological molecules and molecular complexes, the understanding of respective functions in living cells requires application of in situ methods. Obviously, these methods should provide maximal resolution and the best possible preservation of the biological object in a native state, as well as correct statistical evaluation of the spatial characteristics of detected molecular players. Transmission electron microscopy provides the highest possible resolution for analysis of biological samples. The simultaneous detection of biological molecules by means of indirect immunolabeling provides valuable information about their localization in cellular compartments and their possible interactions in macromolecular complexes. To analyze this, we have developed a complex stereological method for statistical evaluation of immunogold clustering and colocalization patterns of antigens on ultrathin sections, including a user-friendly interface. Functional microarchitecture of DNA replication and transcription sites has been successfully characterized using the developed stereological tools. Our data demonstrate that DNA replication is compartmentalized within cell nuclei at the level of DNA foci and support the view...
37

Proteoglycans in the inner limiting membrane and their influence on axonal behavior in embryonic chicken retina

Chai, Lin 08 April 1993 (has links)
Graduation date: 1993
38

Espermatogênese de Zaprionus indianus e Zaprionus sepsoides (Diptera: Drosophilidae): caracterização citoquímica, estrutural e ultraestrutural

Rego, Letícia do Nascimento Andrade de Almeida [UNESP] 24 August 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-08-24Bitstream added on 2014-06-13T18:43:22Z : No. of bitstreams: 1 rego_lnaa_dr_sjrp.pdf: 4366458 bytes, checksum: 268d79cfb562ff5fb2f7391289c1b934 (MD5) / Zaprionus indianus é um drosofilídeo nativo da região Afrotropical que colonizou o continente Sul Americano, apresentando uma ampla distribuição geográfica enquanto Z. sepsoides é restrita a algumas regiões africanas. As duas espécies diferem em relação ao tamanho dos testículos e dos espermatozoides que é maior em Z. indianus do que em Z. sepsoides. Com o intuito de conhecer aspectos da biologia e o grau de diferenciação destas espécies, o presente estudo avaliou a espermatogênese de machos de diferentes idades (1, 3, 5 e 8 dias) de ambas as espécies por meio de técnicas de coloração convencional e de ultraestrutura. A espermatogênese e ultraestrutura dos espermatozoides foram semelhantes nas espécies em que foi confirmado o número diploide de cromossomos com 2n = 12. Entretanto, foi observada uma quantidade maior de espermatozoides em machos jovens (1 a 3 dias de idade) em Z. indianus do que em Z. sepsoides, o qual apresentou maior frequência de estágios iniciais da espermatogênese nestas idades. A porção da cabeça dos espermatozoides foi fortemente marcada nas duas espécies pela coloração por prata (AgNOR), orceína lacto-acética e pela reação de Feulgen. Quando submetidos à reação de P.A.S., os testículos de Z. sepsoides e Z. indianus apresentaram grânulos de glicogênio. As espécies possuem a mesma ultraestrutura flagelar, em que o axonema mostra um arranjo de 9+9+2 microtúbulos, com a presença de dois derivados mitocondriais de diferentes tamanhos e o número de 64 espermatozoides por feixe, em ambas as espécies. A grande semelhança observada no padrão do arranjo de microtúbulos do axonema e nos derivados mitocondriais com diferentes tamanhos nas espécies de Zaprionus, comparadas com outras espécies de Drosophila, é indicativa da conservação destas estruturas na família Drosophilidae... / Zaprionus indianus is a drosophilid native to the Afrotropical region that has colonized South America. Z. indianus exhibits a wide geographical distribution, whereas Z. sepsoides is restricted to certain African regions. The two species differ in the size of their testes, which are larger in Z. indianus than in Z. sepsoides. To better understand the biology and the degree of differentiation of these species, the current study evaluated spermatogenesis in males of different ages (1, 3, 5 and 8 days old) from both species by conventional staining techniques and ultrastructural analysis. Spermatogenesis and the ultrastructure of spermatozoa were similar in the two species, for which the diploid number was confirmed to be 2n = 12 chromosomes. However, a greater number of spermatozoa were observed in young Z. indianus males (1-3 days old) than in young Z. sepsoides males, which showed a higher frequency of cells at the early stages of spermatogenesis at this age. A portion of the head of the sperm was strongly marked in both species by silver staining (AgNOR), lacto-acetic orcein and the Feulgen reaction. Additionally, when submitted to P.A.S. reaction, the testes of both Z. sepsoides and Z. indianus exhibited glycogen granules. The two species also presented the same flagellar ultrastructure, in which the axoneme includes a 9+9+2 arrangement of microtubules, two mitochondrial derivatives of different sizes are present and the number of spermatozoa per bundle is 64. The great similarity in the pattern of microtubule arrangement in the axoneme and in the mitochondrial derivatives of the species Zaprionus, as compared with other species of Drosophila, indicates that these structures are preserved in the family Drosophilidae. The differences observed between the young males of Z. indianus and Z. sepsoides, including the number and frequency of sperm... (Complete abstract click electronic access below)
39

Germination and seedling growth of amburana cearensis (AllemÃo) A.C. smith as a function the weight of seeds and abiotic factors / GerminaÃÃo e crescimento de plÃntulas de amburana cearensis (AllemÃo) A.C. smith em funÃÃo do peso de sementes e fatores abiÃticos

JoÃo Paulo Nobre de Almeida 20 February 2014 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Given the needs of reclamation is increasing interest in the propagation of native species, which requires basic information about their germination characteristics and ecophysiological. The Amburana cearensis (AllemÃo) A.C. Smith known as cumaru is a species widely used for restoration of the landscape. The aim of this study was to investigate the germination and seedling growth of cumaru depending on the weight of the seeds under conditions of light, temperature, drought stress, as well as to determine the seed imbibition curve, internal morphology, chemical composition and quantification of the coumarin. Initially seeds were individually weighed and separated into three weight classes (light, medium and heavy), these being submitted to the determination of water content, thousand seeds weight and germination tests in two light conditions (presence and absence ) and six schemes temperatures (20, 25, 30, 35, 40, and 20-30 ÂC). In addition to these tests, it was determined the imbibition curve of each weight class and made assessment of drought stress tolerance under different potentials(-0.2, -0.4, -0.6, -0.8 and -1,0 MPa). The experiments were arranged in a completely randomized design in four replications for each treatment. For the internal morphology of seeds were used in cytochemistry usual techniques for the identification of the main structures and substances reserves. To visualize the coumarin in the seeds by NMR spectroscopy was used. The optimum conditions for seed germination occurred at 30 ÂC, which are insensitive to light and vigor seeds for light and medium. The best conditions for seedling growth occurred with the light and medium seeds at 25 and 30 ÂC and in the presence of light, with temperatures of 35 and 40 ÂC harmful. Light and medium seeds showed the same pattern of water absorption, while not reach the heavy phase III of the curve. The decrease in the water potential of the substrate affect the germination and growth of seedlings from seed medium and heavy compared to the light, and from -0.6 MPa in a condition strictly limiting seedling development. The chemical constituents present in the seeds of A. cearensis are quantitatively different depending on the weight of the seeds, and the heavy characterized by a high content of lipids. The NMR spectroscopy falls greater proportion of coumarin in seed extract heavy and medium, possibly affecting ecophysiological needs of the species A. cearensis. / Diante das necessidades de recuperaÃÃo de Ãreas degradadas à crescente o interesse na propagaÃÃo de espÃcies florestais nativas, o que demanda informaÃÃes bÃsicas sobre as suas caracterÃsticas germinativas e ecofisiolÃgicas. A Amburana cearensis (AllemÃo) A.C. Smith conhecida como cumaru à uma espÃcie bastante utilizada para recomposiÃÃo da paisagem. O objetivo deste trabalho foi estudar a germinaÃÃo e o crescimento de plÃntulas de cumaru em funÃÃo do peso das sementes sob diferentes condiÃÃes de temperatura, luz, estresse hÃdrico, bem como determinar nas sementes a curva de embebiÃÃo, morfologia interna, composiÃÃo quÃmica e identificaÃÃo da cumarina. Inicialmente as sementes foram pesadas individualmente e separadas em trÃs classes de peso (leves, mÃdias e pesadas), sendo estas, submetidas à determinaÃÃo dos teores de Ãgua, peso de mil de sementes e a testes de germinaÃÃo em duas condiÃÃes de luz (presenÃa e ausÃncia) e seis regimes de temperatura (20, 25, 30, 35, 40 e 20-30ÂC). AlÃm destes ensaios, foi determinado a curva de embebiÃÃo de cada classe de peso e avaliaÃÃo da tolerÃncia ao estresse hÃdrico sob diferentes potenciais (-0,2, -0,4, -0,6, -0,8 e -1,0 MPa). Os experimentos foram dispostos em delineamento inteiramente casualizado com quatro repetiÃÃes para cada tratamento. Para a morfologia interna das sementes foram utilizadas tÃcnicas usuais em citoquÃmica para a identificaÃÃo das principais estruturas e substÃncias de reservas. Para a visualizaÃÃo da cumarina nas sementes foi utilizada a espectroscopia por RMN. As condiÃÃes Ãtimas para a germinaÃÃo das sementes ocorreu na temperatura de 30ÂC, sendo estas insensÃveis à luz e um maior vigor para sementes leves e mÃdias. As melhores condiÃÃes para o crescimento das plÃntulas ocorreram com as sementes leves e mÃdias nas temperaturas de 25 e 30ÂC e na presenÃa de luz, sendo as temperaturas de 35 e 40 ÂC prejudiciais. Sementes leves e mÃdias apresentam o mesmo padrÃo de absorÃÃo de Ãgua, enquanto as pesadas nÃo atingem a fase III da curva. O decrÃscimo do potencial hÃdrico do substrato prejudica a germinaÃÃo e o crescimento de plÃntulas oriundas de sementes mÃdias e pesadas em comparaÃÃo Ãs leves, sendo a partir de -0,6 MPa uma condiÃÃo estritamente limitante na formaÃÃo de plÃntulas. Os constituintes quÃmicos presentes nas sementes de A. cearensis sÃo quantitativamente diferenciados em funÃÃo do peso das sementes, sendo as pesadas caracterizadas por um elevado teor de lipÃdios. A espectroscopia por RMN releva uma maior proporÃÃo de cumarina no extrato de sementes pesadas e mÃdias, que possivelmente afetam as necessidades ecofisiolÃgicas da espÃcie A. cearensis.
40

Propriedades do sangue e efeito do mergulho forçado sobre o perfil hematológico de Podocnemis erythrocephala (Spix, 1824) (Testudines, Podocnemididae) do Médio Rio Negro, Amazonas

Santos, Marcio Quara de Carvalho 31 May 2011 (has links)
Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-08-25T14:09:38Z No. of bitstreams: 1 Dissertação - Marcio Quara de Carvalho Santos.pdf: 1229782 bytes, checksum: 8267f9cceff2df674e6c6cc9de3ac713 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-08-26T20:31:16Z (GMT) No. of bitstreams: 1 Dissertação - Marcio Quara de Carvalho Santos.pdf: 1229782 bytes, checksum: 8267f9cceff2df674e6c6cc9de3ac713 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-08-26T20:38:37Z (GMT) No. of bitstreams: 1 Dissertação - Marcio Quara de Carvalho Santos.pdf: 1229782 bytes, checksum: 8267f9cceff2df674e6c6cc9de3ac713 (MD5) / Made available in DSpace on 2015-08-26T20:38:37Z (GMT). No. of bitstreams: 1 Dissertação - Marcio Quara de Carvalho Santos.pdf: 1229782 bytes, checksum: 8267f9cceff2df674e6c6cc9de3ac713 (MD5) Previous issue date: 2011-05-31 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / Irapuca, Podocnemis erythrocephala, is the poorly studied turtle species among the Amazonian Podocnemis and suffers from large predatory pressure by the human population, causing a decline in their natural stocks. This study aimed to determine the hematological parameters, the morphological and cytochemical features of blood cells, as well as the effect of forced diving on the blood profile of P. erythrocephala, generating relevant information to the proposition of management plans and conservation strategies for this species. Analysis revealed that sex exercised little influence on the blood profile of the animals, unlike the growth. It was found that hatchlings showed lower eritrogram than immature and mature animals, unlike the concentrations of glucose and total cholesterol that were higher, confirming the high metabolic rate of hatchlings. Overall, the changes found in blood parameters reflected changes in physiological function of the behavior and natural history of the species. Due the effect of sex and development phase on the blood parameters, reference ranges were established for hatchlings, immature males, mature males, immature females and mature females. From the morphological analysis of blood cells from irapuca erythrocytes, thrombocytes, lymphocytes, azurophilic, heterophils, eosinophils and basophils were identified with morphological characteristics similar to those described for other Podocnemidid species. Cytochemical analysis indicated that heterophils, eosinophils and basophils are the most active cells of the immune system of this species, being primarily responsible for phagocytic activity due the presence of glycogen, lipid and peroxidase. No changes were observed on the eritrogram of animals subjected to 30 and 60 minutes of forced submersion. Increased levels of plasma lactate, calcium and magnesium, according to the dive time, reflected physiological adjustments to maintain the acid-base balance, whereas changes in the levels of total cholesterol and triglycerides indicated that during anoxia, the irapuca activated the ATP production from lipid catabolism, as a complementary way to anaerobic glycolysis. The irapuca proved to be a tolerant species to 60 minutes of forced diving, although higher periods might cause metabolic acidosis and depletion of energy substrates. These values constitute a basis for assessing the health status of wild irapucas. / A irapuca, Podocnemis erythrocephala, é a espécie menos estudada entre os podocnemidídeos amazônicos e vem sofrendo grande pressão antrópica, que tem contribuído para o declínio de seus estoques naturais. Este trabalho teve como objetivo determinar os parâmetros hematológicos, as características morfológicas e citoquímicas das células do sangue, bem como o efeito do mergulho forçado sobre o perfil sanguíneo de P. erythrocephala, gerando informações relevantes para a elaboração de planos de manejo e estratégias de conservação para a espécie. As análises revelaram que o sexo exerceu menor influência sobre o perfil hematológico dos animais, diferentemente do crescimento. Foi verificado que espécimes recém-eclodidos apresentaram valores do eritrograma inferiores em relação aos animais imaturos e maduros, ao contrário das concentrações de glicose e colesterol total, que foram superiores, confirmando a alta demanda metabólica que os recém-eclodidos possuem. De forma geral, as alterações encontradas nos parâmetros sanguíneos refletiram adaptações fisiológicas em função do comportamento e da história natural da espécie. Em função do efeito do sexo e da fase de crescimento sobre os parâmetros sanguíneos, foram estabelecidos intervalos de referência para recém-eclodidos, machos imaturos, machos maduros, fêmeas imaturas e fêmeas maduras. A partir da análise morfológica das células sanguíneas da irapuca, foram identificados eritrócitos, trombócitos, linfócitos, azurófilos, heterófilos, eosinófilos e basófilos com características morfológicas semelhantes às descritas para outros podocnemidídeos. As análises dos constituintes citoquímicos indicaram que os heterófilos, eosinófilos e basófilos são as células mais ativas do sistema imunológico nesta espécie, sendo responsáveis principalmente pela atividade fagocítica, devido a presença de glicogênio, lipídeos e peroxidase. Não foram observadas alterações no eritrograma dos animais submetidos a 30 e 60 minutos de submersão forçada. O aumento nos níveis plasmáticos de lactato, cálcio e magnésio, em função do tempo de mergulho, refletiram ajustes fisiológicos para a manutenção do equilíbrio ácido-base, enquanto que as alterações nos níveis de triglicerídeos e colesterol total indicam que, em situações de anóxia, a irapuca ativa o catabolismo lipídico para a produção de ATP, de forma complementar à glicólise anaeróbica. A irapuca demonstrou ser uma espécie resistente à 60 minutos de mergulho forçado, entretanto períodos superiores podem causar acidose metabólica e exaustão dos substratos energéticos. As informações geradas no presente estudo servirão de base para a avaliação do estado de saúde desta espécie de quelônio amazônico.

Page generated in 0.0575 seconds