Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante
Autor(a) principal: | |
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Data de Publicação: | 2023 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFS |
Texto Completo: | https://ri.ufs.br/jspui/handle/riufs/19216 |
Resumo: | It is a consensus within the scientific community the need to broaden the understanding of the biophysics involved in the processes of induction of biological damage caused by low and moderate doses of radiation, both for protection against their undesirable effects and for modulating them for multifaceted applications. The use of higher plants in bioassays is a widely employed tool for the detection and screening of potentially genotoxic agents. Among plant species, onion (Allium cepa) is one of the most used models for determining the genotoxic potential of various chemicals, with effects that were comparable in up to 82% between tests to determine genetic abnormalities carried out with animal models. However, its use for investigating radio-induced toxicity remains insufficiently explored. In this work, Allium cepa roots were irradiated with 241Am and 90Sr/90Y sources, emitting a and B particles, respectively, aiming to quantify the frequencies of major radioinduced cytogenetic endpoints and select the most suitable one for plotting cytogenetic dose-response curves. Computational simulations of the experimental scenarios were performed using Monte Carlo codes to determine the absorbed dose rates by Allium cepa roots. Additionally, for the B irradiations, a TL dose-response curve was plotted for comparison purposes using TLD-100 irradiations with the same experimental setup used for the Allium cepa root irradiations. Parameters such as differences in LET, dose rates, absorbed doses, as well as the influence of different time intervals after irradiation, were considered. The main results include a linear dependence of micronucleus frequency on dose for a particle irradiation, from 0.02 to 0.08 Gy, with cytotoxic activity starting at 0.1 Gy. On the other hand, for B particle irradiations, within the range of 0.04 to 1.44 Gy, the dependence of micronucleus frequencies on doses was nonlinear. Cytotoxic activity was not detected, but an aggravation of genotoxic damage was observed from 0.72 Gy, detected as cells with two and three micronuclei. Analyses of temporal evolution after three cell cycles following irradiations indicated potential for chromosomal instability through micronucleus frequencies. Data on the influences of different absorbed dose rates of B particles (D 1 = 1.4 ± 0.1 mGy/s, D 2 = 5.3 ± 2.3 mGy/s, D 3 = 12.2 ± 3.4 mGy/s e D 4 = 13.9 ± 3.2 mGy/s) while keeping the absorbed dose fixed (0.72 Gy) revealed distinct behaviors in radio-induced micronucleus frequencies, but all influenced by changes in the mitotic index. Following these analyses, a mathematical model was proposed that incorporated a correction factor that approximates the estimated absorbed beta radiation dose detected via micronucleus frequency to the absorbed dose detected via conventional TL dosimetry. This correction factor allowed for subtracting the influence of the quadratic coefficient from the linear coefficient of the dose, based on radiobiological fundamentals. This, in turn, showed that as the dose was increased, the quadratic coefficient exerted greater influence on the dose estimate, mainly due to the possible increase in mutagenic activity. In conclusion, the frequency of micronuclei in Allium cepa cells showed potential for use as a cytogenetic biodosimeter, provided appropriate radiobiological considerations and mathematical adjustments are made. |
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Xavier, Magno NogueiraLalic, Susana de Souza2024-03-05T20:05:43Z2024-03-05T20:05:43Z2023-07-28XAVIER, Magno Nogueira. Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante. 2023. 117 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2023.https://ri.ufs.br/jspui/handle/riufs/19216It is a consensus within the scientific community the need to broaden the understanding of the biophysics involved in the processes of induction of biological damage caused by low and moderate doses of radiation, both for protection against their undesirable effects and for modulating them for multifaceted applications. The use of higher plants in bioassays is a widely employed tool for the detection and screening of potentially genotoxic agents. Among plant species, onion (Allium cepa) is one of the most used models for determining the genotoxic potential of various chemicals, with effects that were comparable in up to 82% between tests to determine genetic abnormalities carried out with animal models. However, its use for investigating radio-induced toxicity remains insufficiently explored. In this work, Allium cepa roots were irradiated with 241Am and 90Sr/90Y sources, emitting a and B particles, respectively, aiming to quantify the frequencies of major radioinduced cytogenetic endpoints and select the most suitable one for plotting cytogenetic dose-response curves. Computational simulations of the experimental scenarios were performed using Monte Carlo codes to determine the absorbed dose rates by Allium cepa roots. Additionally, for the B irradiations, a TL dose-response curve was plotted for comparison purposes using TLD-100 irradiations with the same experimental setup used for the Allium cepa root irradiations. Parameters such as differences in LET, dose rates, absorbed doses, as well as the influence of different time intervals after irradiation, were considered. The main results include a linear dependence of micronucleus frequency on dose for a particle irradiation, from 0.02 to 0.08 Gy, with cytotoxic activity starting at 0.1 Gy. On the other hand, for B particle irradiations, within the range of 0.04 to 1.44 Gy, the dependence of micronucleus frequencies on doses was nonlinear. Cytotoxic activity was not detected, but an aggravation of genotoxic damage was observed from 0.72 Gy, detected as cells with two and three micronuclei. Analyses of temporal evolution after three cell cycles following irradiations indicated potential for chromosomal instability through micronucleus frequencies. Data on the influences of different absorbed dose rates of B particles (D 1 = 1.4 ± 0.1 mGy/s, D 2 = 5.3 ± 2.3 mGy/s, D 3 = 12.2 ± 3.4 mGy/s e D 4 = 13.9 ± 3.2 mGy/s) while keeping the absorbed dose fixed (0.72 Gy) revealed distinct behaviors in radio-induced micronucleus frequencies, but all influenced by changes in the mitotic index. Following these analyses, a mathematical model was proposed that incorporated a correction factor that approximates the estimated absorbed beta radiation dose detected via micronucleus frequency to the absorbed dose detected via conventional TL dosimetry. This correction factor allowed for subtracting the influence of the quadratic coefficient from the linear coefficient of the dose, based on radiobiological fundamentals. This, in turn, showed that as the dose was increased, the quadratic coefficient exerted greater influence on the dose estimate, mainly due to the possible increase in mutagenic activity. In conclusion, the frequency of micronuclei in Allium cepa cells showed potential for use as a cytogenetic biodosimeter, provided appropriate radiobiological considerations and mathematical adjustments are made.É consensual na comunidade científica a necessidade de ampliar a compreensão sobre a biofísica envolvida nos processos de indução de danos biológicos causados por doses baixas e moderadas de radiação, tanto para proteção contra os seus efeitos indesejáveis, quanto para modulá-los para aplicações multifacetadas. O uso de plantas superiores em bioensaios é uma ferramenta amplamente utilizada para detecção e triagem de agentes potencialmente genotóxicos. Entre as espécies vegetais, a cebola (Allium cepa) é um dos modelos mais utilizados para determinação de potencial genotóxico de diversos químicos, com efeitos que se mostraram comparáveis em até 82% entre testes de determinação de anormalidades genéticas realizados com modelos animais. Em contrapartida, seu uso para investigação de toxicidade radioinduzida permanece insuficientemente explorado. Neste trabalho, raízes de Allium cepa foram irradiadas com fontes de 241Am e 90Sr/90Y, emissoras de partículas a e B, respectivamente, objetivando quantificar as frequências dos principais endpoints citogenéticos radioinduzidos e selecionar o mais indicado para a plotagem de curvas de dose-resposta. Simulações computacionais dos cenários experimentais foram realizadas usando códigos de Monte Carlo, a fim de determinar as taxas de doses absorvidas pelas raízes de Allium cepa. Adicionalmente, para as irradiações B, uma curva de dose-resposta TL foi plotada para fins de comparação usando irradiações de TLD-100 com a mesma configuração experimental utilizada para as irradiações das raízes de Allium cepa. Parâmetros como diferenças na LET, taxas de doses e doses absorvidas, bem como a influência de diferentes intervalos após as irradiações foram considerados. Os principais resultados incluem uma dependência linear da frequência de micronúcleos com a dose para a irradiação com partículas a, de 0,02 a 0,08 Gy, com início de atividade citotóxica a partir de 0,1 Gy. Por outro lado, para as irradiações com partículas B, dentro do intervalo de 0,04 a 1,44 Gy, a dependência das frequências de micronúcleos com as doses foi não-linear. Não foi detectada a presença de atividade citotóxica, mas houve agravamento do dano genotóxico a partir de 0,72 Gy, detectado como células com dois e três micronúcleos. As análises da evolução temporal após três ciclos celulares de cessadas às irradiações, indicaram por meio das frequências de micronúcleos, potencial para instabilidade cromossômica. Os dados sobre as influências de diferentes taxas de doses absorvidas de partículas B (D1 = 1,4 ± 0,1 mGy/s, D 2 = 5,3 ± 2,3 mGy/s, D 3 = 12,2 ± 3,4 mGy/s e D 4 = 13,9 ± 3,2 mGy/s) mantendo-se fixa a dose absorvida (0,72 Gy), revelaram comportamentos distintos nas frequências de micronúcleos radioinduzidas, porém, todas influenciadas por alterações do índice mitótico. Após essas análises, foi proposto um modelo matemático que incorporou um fator de correção que aproxima a estimativa da dose de radiação beta absorvida detectada via frequência de micronúcleos da dose absorvida detectada via dosimetria TL convencional. Este fator de correção permitiu subtrair a influência do coeficiente quadrático no coeficiente linear da dose, com base em fundamentos radiobiológicos. Isso, por sua vez, mostrou que conforme a dose foi aumentada, o coeficiente quadrático exerceu maior influência na estimativa da dose, principalmente devido ao possível aumento da atividade de mutagenicidade. Como conclusão, a frequência de MN em células de Allium cepa mostrou potencial para ser usada como um biodosímetro citogenético, desde que sejam feitas considerações radiobiológicas e ajustes matemáticos apropriados.Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPqSão CristóvãoporAllium cepaBiofísica das radiaçõesBioindicadoresMicronúcleoProteção radiológicaRadioatividadeRadiation biophysicsBioindicatorsMicronucleusRadiological protectionRadioactivityCIENCIAS EXATAS E DA TERRA::FISICAViabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizanteinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisPós-Graduação em FísicaUniversidade Federal de Sergipe (UFS)reponame:Repositório Institucional da UFSinstname:Universidade Federal de Sergipe (UFS)instacron:UFSinfo:eu-repo/semantics/openAccessLICENSElicense.txtlicense.txttext/plain; charset=utf-81475https://ri.ufs.br/jspui/bitstream/riufs/19216/1/license.txt098cbbf65c2c15e1fb2e49c5d306a44cMD51ORIGINALMAGNO_NOGUEIRA_XAVIER.pdfMAGNO_NOGUEIRA_XAVIER.pdfapplication/pdf2725118https://ri.ufs.br/jspui/bitstream/riufs/19216/2/MAGNO_NOGUEIRA_XAVIER.pdf75401a7eb6a5d4a70e92d0ec0244f86fMD52riufs/192162024-03-05 17:05:49.023oai:ufs.br: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Repositório InstitucionalPUBhttps://ri.ufs.br/oai/requestrepositorio@academico.ufs.bropendoar:2024-03-05T20:05:49Repositório Institucional da UFS - Universidade Federal de Sergipe (UFS)false |
dc.title.pt_BR.fl_str_mv |
Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante |
title |
Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante |
spellingShingle |
Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante Xavier, Magno Nogueira Allium cepa Biofísica das radiações Bioindicadores Micronúcleo Proteção radiológica Radioatividade Radiation biophysics Bioindicators Micronucleus Radiological protection Radioactivity CIENCIAS EXATAS E DA TERRA::FISICA |
title_short |
Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante |
title_full |
Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante |
title_fullStr |
Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante |
title_full_unstemmed |
Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante |
title_sort |
Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante |
author |
Xavier, Magno Nogueira |
author_facet |
Xavier, Magno Nogueira |
author_role |
author |
dc.contributor.author.fl_str_mv |
Xavier, Magno Nogueira |
dc.contributor.advisor1.fl_str_mv |
Lalic, Susana de Souza |
contributor_str_mv |
Lalic, Susana de Souza |
dc.subject.por.fl_str_mv |
Allium cepa Biofísica das radiações Bioindicadores Micronúcleo Proteção radiológica Radioatividade |
topic |
Allium cepa Biofísica das radiações Bioindicadores Micronúcleo Proteção radiológica Radioatividade Radiation biophysics Bioindicators Micronucleus Radiological protection Radioactivity CIENCIAS EXATAS E DA TERRA::FISICA |
dc.subject.eng.fl_str_mv |
Radiation biophysics Bioindicators Micronucleus Radiological protection Radioactivity |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::FISICA |
description |
It is a consensus within the scientific community the need to broaden the understanding of the biophysics involved in the processes of induction of biological damage caused by low and moderate doses of radiation, both for protection against their undesirable effects and for modulating them for multifaceted applications. The use of higher plants in bioassays is a widely employed tool for the detection and screening of potentially genotoxic agents. Among plant species, onion (Allium cepa) is one of the most used models for determining the genotoxic potential of various chemicals, with effects that were comparable in up to 82% between tests to determine genetic abnormalities carried out with animal models. However, its use for investigating radio-induced toxicity remains insufficiently explored. In this work, Allium cepa roots were irradiated with 241Am and 90Sr/90Y sources, emitting a and B particles, respectively, aiming to quantify the frequencies of major radioinduced cytogenetic endpoints and select the most suitable one for plotting cytogenetic dose-response curves. Computational simulations of the experimental scenarios were performed using Monte Carlo codes to determine the absorbed dose rates by Allium cepa roots. Additionally, for the B irradiations, a TL dose-response curve was plotted for comparison purposes using TLD-100 irradiations with the same experimental setup used for the Allium cepa root irradiations. Parameters such as differences in LET, dose rates, absorbed doses, as well as the influence of different time intervals after irradiation, were considered. The main results include a linear dependence of micronucleus frequency on dose for a particle irradiation, from 0.02 to 0.08 Gy, with cytotoxic activity starting at 0.1 Gy. On the other hand, for B particle irradiations, within the range of 0.04 to 1.44 Gy, the dependence of micronucleus frequencies on doses was nonlinear. Cytotoxic activity was not detected, but an aggravation of genotoxic damage was observed from 0.72 Gy, detected as cells with two and three micronuclei. Analyses of temporal evolution after three cell cycles following irradiations indicated potential for chromosomal instability through micronucleus frequencies. Data on the influences of different absorbed dose rates of B particles (D 1 = 1.4 ± 0.1 mGy/s, D 2 = 5.3 ± 2.3 mGy/s, D 3 = 12.2 ± 3.4 mGy/s e D 4 = 13.9 ± 3.2 mGy/s) while keeping the absorbed dose fixed (0.72 Gy) revealed distinct behaviors in radio-induced micronucleus frequencies, but all influenced by changes in the mitotic index. Following these analyses, a mathematical model was proposed that incorporated a correction factor that approximates the estimated absorbed beta radiation dose detected via micronucleus frequency to the absorbed dose detected via conventional TL dosimetry. This correction factor allowed for subtracting the influence of the quadratic coefficient from the linear coefficient of the dose, based on radiobiological fundamentals. This, in turn, showed that as the dose was increased, the quadratic coefficient exerted greater influence on the dose estimate, mainly due to the possible increase in mutagenic activity. In conclusion, the frequency of micronuclei in Allium cepa cells showed potential for use as a cytogenetic biodosimeter, provided appropriate radiobiological considerations and mathematical adjustments are made. |
publishDate |
2023 |
dc.date.issued.fl_str_mv |
2023-07-28 |
dc.date.accessioned.fl_str_mv |
2024-03-05T20:05:43Z |
dc.date.available.fl_str_mv |
2024-03-05T20:05:43Z |
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info:eu-repo/semantics/publishedVersion |
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info:eu-repo/semantics/doctoralThesis |
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doctoralThesis |
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dc.identifier.citation.fl_str_mv |
XAVIER, Magno Nogueira. Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante. 2023. 117 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2023. |
dc.identifier.uri.fl_str_mv |
https://ri.ufs.br/jspui/handle/riufs/19216 |
identifier_str_mv |
XAVIER, Magno Nogueira. Viabilidade do uso de biota vegetal para caracterização biofísica e análise dosimétrica de danos citogenéticos induzidos por radiação ionizante. 2023. 117 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2023. |
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https://ri.ufs.br/jspui/handle/riufs/19216 |
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