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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

Efeitos de microcistinas em Piaractus brachypomus (Actinopterygii, Characidae) e o perfil do consumo de peixes pela comunidade da UFG / Effects of microcystins on Piaractus brachypomus (Actinopterygii, Characidae) and the profile of fish consumption by the UFG community

Bezerra, Roberto Araujo 08 June 2017 (has links)
Submitted by JÚLIO HEBER SILVA (julioheber@yahoo.com.br) on 2018-06-19T19:39:34Z No. of bitstreams: 2 Tese - Roberto Araujo Bezerra - 2017.pdf: 6402541 bytes, checksum: ed090dd91775b5a16e6798f3fdfa191e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-06-27T10:33:26Z (GMT) No. of bitstreams: 2 Tese - Roberto Araujo Bezerra - 2017.pdf: 6402541 bytes, checksum: ed090dd91775b5a16e6798f3fdfa191e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-06-27T10:33:26Z (GMT). No. of bitstreams: 2 Tese - Roberto Araujo Bezerra - 2017.pdf: 6402541 bytes, checksum: ed090dd91775b5a16e6798f3fdfa191e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-06-08 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The world's fishery production is constantly growing, with expansion of aquaculture parks, fish farms and fish-pay, however, these activities can trigger damages to aquatic systems. The process of eutrophication is characterized by the excess of nutrients available in the water, which when associated with high temperatures and luminosity, provide cyanobacteria blooms, some of which are toxic. Microcystins pose risks to human and other animal health due to the consumption of contaminated fish and can cause serious problems for the aquatic community. The present study had as main objective to evaluate the mutagenic damages that toxic blooms of Microcystis aeruginosa and Microcystis panniformis in different densities of cells can cause when exposed to the Piaractus brachypomus (pirapitinga), native species of the Amazon basin and commercialized in fish farms and fish-pays of the Goiânia metropolitan region, and to evaluate the profile of fish consumption by the community of the Federal University of Goiás. The results showed that even at low densities, the effect of microcystins generated different genomic damages in fish. Juveniles presented erythrocytic nuclear alterations exposed to M. aeruginosa - reniformes: 33%; binucleate: 28.6%; micronucleus: 28.1% and exposed to M. panniformis reniformes: 6.43%; binucleate: 75.5%; micronucleus: 2.4%. There was a higher concentration of microcystins produced by M. panniformis cells. As for the profile of the academic community, more than 80% consume fish, since tilapia is the most preferred species among respondents (22.4%). Of these, only 49.6% go to fish-pay and the main reason for going is leisure with family or friends (46.7%), however, only 21.7% take into account the hygiene of the place, but are unaware of the quality of the waters of these places, as well as that of fish. It was concluded in this study that the group most threatened by the action of cyanotoxins are the fish consumers themselves due to the low concentration found in the muscular tissues and that when investigated, some do not reach the peak of detection, passing unnoticed by the human population. / A produção pesqueira mundial está em constante crescimento, com expansão de parques aquícolas, pisciculturas e pesque-pague, no entanto, essas atividades podem desencadear danos aos sistemas aquáticos. O processo de eutrofização é caracterizado pelo excesso de nutrientes disponibilizados na água, que quando associados a elevadas temperaturas e luminosidade, proporcionam florações de cianobactérias, sendo algumas tóxicas. As microcistinas oferecem riscos à saúde humana e de outros animais devido ao consumo de peixe contaminado, podendo causar sérios problemas à comunidade aquática. O presente estudo teve como objetivo principal avaliar os danos mutagênicos que florações tóxicas de Microcystis aeruginosa e Microcystis panniformis em diferentes densidades de células podem ocasionar quando expostas à Piaractus brachypomus (pirapitinga), espécie nativa da bacia Amazônica e comercializada em pisciculturas e pesque-pague da região metropolitana de Goiânia/GO, e avaliar o perfil do consumo de peixes pela comunidade da Universidade Federal de Goiás. Os resultados demonstraram que mesmo em baixas densidades, o efeito das microcistinas geraram diferentes danos genômicos nos peixes. Os juvenis apresentaram alterações nucleares eritrocíticas expostos à M. aeruginosa - reniformes: 33%; binucleadas: 28,6%; micronúcleo: 28,1% e expostos à M. panniformis – reniformes: 6,43%; binucleadas: 75,5%; micronúcleo: 2,4%. Verificou-se maior concentração de microcistinas produzidas por células de M. panniformis. Quanto ao perfil da comunidade acadêmica, mais de 80% consomem peixes, posto que a tilápia é a espécie de maior preferência pelos entrevistados (22,4%). Destes, apenas 49,6% frequentam pesque-pague e o principal motivo pela ida é o lazer em família ou com amigos (46,7%), todavia, apenas 21,7% levam em consideração a higiene do local, mas desconhecem a qualidade das águas desses locais, bem como a dos peixes. Concluiu-se neste estudo, que o grupo mais ameaçado pela ação das cianotoxinas são os próprios consumidores de peixe, devido à baixa concentração encontrada nos tecidos musculares e que quando investigadas, algumas não atingem o pico de detecção, passando despercebido pala população humana.
2

L'activador del CDK2 relacionat amb l'apoptosi: clonatge i estudi bioquímic del seu paper regulador de la mort cel·lular programada

Brunet Roig, Maurici 14 July 2006 (has links)
L´apoptosi, o mort cel.lular programada, és un procés actiu que mobilitza els recursos cel.lulars amb l´objectiu de mantenir l´homeostasi de l´organisme a expenses del suïcidi de cèl.lules individuals. Diferents estudis han mostrat un increment de l´activiat d´algunes cdk, especialment Cdk1 i Cdk2, en correlació amb la progressió dels primers estadis apoptòtics. En el nostre laboratori l´estudi de l´apoptosi en timòcits, els quals no tenen una activitat cdk significativa degut a l´aturada del cicle cel.lular en G1, demostren que la inducció de l´activitat de Cdk2 després del tractament amb radiació gamma o amb glucocorticoides és necessària per l´inici de l´apoptosi. Mentre cap de les ciclines conegudes sembla ser la proteïna activadora de Cdk2 en apoptosi, en el nostre laboratori hem identificat un nou membre de la família de les ciclines, denominada Ciclina O, capaç d´activar aquesta kinasa in vivo en línies cel.lulars. L´expressió d´aquesta nova ciclina en el timus, i altres teixits, s´indueix ràpidament després del tractament amb radiació gamma i coincideix amb l´aparició de l´apoptosi. Aquests resultats posicionen la Ciclina O com a millor candidat a ser l´activador de Cdk2 necessari per induïr la mort cel.lular programada en el timus, i probablement també en altres òrgans. / The apoptosis, also called programmed cell death, is an active process able to use the cellular mechanisms to kill individual cells in order to keep the functional homeostasis of the whole organism. Different studies had shown a correlation between the first apoptotic events and the induction of some cdk proteins, particularly Cdk1 and Cdk2. The studies of thymocytes in our laboratory, wich lacks the most amount of cdk activity related to the cell cycle because of its arrest in G1, had shown that the induction of Cdk2 activity after the treatment with gamma radiation or glucocorticoids is a necessary step for the apoptosis induction. While any of the cyclins described at the moment seems to be the Cdk2 activator for apoptosis a new member of the cyclin family able to activate the kinase Cdk2 in vivo in cell lines has been identified in our laboratory. The expresion of this cyclin, known as Cyclin O, is quickly induced in the thymus after the treatment with gamma radiation and correlates with the induction of apoptosis. These results position Cyclin O as the best candidate to activate Cdk2 and inuce the programmed cell death in the thymus, and probably other tissues.

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