Investigating the effects of chronic low-dose radiation exposure in the liver of a hypothermic zebrafish model

Mankind's quest for a manned mission to Mars is placing increased emphasis on the development of innovative radio-protective countermeasures for long-term space travel. Hibernation confers radio-protective effects in hibernating animals, and this has led to the investigation of synthetic torpor to mitigate the deleterious effects of chronic low-dose-rate radiation exposure. Here we describe an induced torpor model we developed using the zebrafish. We explored the effects of radiation exposure on this model with a focus on the liver. Transcriptomic and behavioural analyses were performed. Radiation exposure resulted in transcriptomic perturbations in lipid metabolism and absorption, wound healing, immune response, and fibrogenic pathways. Induced torpor reduced metabolism and increased pro-survival, anti-apoptotic, and DNA repair pathways. Coupled with radiation exposure, induced torpor led to a stress response but also revealed maintenance of DNA repair mechanisms, pro-survival and anti-apoptotic signals. To further characterise our model of induced torpor, the zebrafish model was compared with hepatic transcriptomic data from hibernating grizzly bears (Ursus arctos horribilis) and active controls revealing conserved responses in gene expression associated with anti-apoptotic processes, DNA damage repair, cell survival, proliferation, and antioxidant response. Similarly, the radiation group was compared with space-flown mice revealing shared changes in lipid metabolism

Investigating the effects of chronic low-dose radiation exposure in the liver of a hypothermic zebrafish model

Abstract Mankind’s quest for a manned mission to Mars is placing increased emphasis on the development of innovative radio-protective countermeasures for long-term space travel. Hibernation confers radio-protective effects in hibernating animals, and this has led to the investigation of synthetic torpor to mitigate the deleterious effects of chronic low-dose-rate radiation exposure. Here we describe an induced torpor model we developed using the zebrafish. We explored the effects of radiation exposure on this model with a focus on the liver. Transcriptomic and behavioural analyses were performed. Radiation exposure resulted in transcriptomic perturbations in lipid metabolism and absorption, wound healing, immune response, and fibrogenic pathways. Induced torpor reduced metabolism and increased pro-survival, anti-apoptotic, and DNA repair pathways. Coupled with radiation exposure, induced torpor led to a stress response but also revealed maintenance of DNA repair mechanisms, pro-survival and anti-apoptotic signals. To further characterise our model of induced torpor, the zebrafish model was compared with hepatic transcriptomic data from hibernating grizzly bears (Ursus arctos horribilis) and active controls revealing conserved responses in gene expression associated with anti-apoptotic processes, DNA damage repair, cell survival, proliferation, and antioxidant response. Similarly, the radiation group was compared with space-flown mice revealing shared changes in lipid metabolism

Ciência e racismo: uma leitura crítica de Raça e assimilação em Oliveira Vianna Science and racism: a critical look on Raça e assimilação in Oliveira Vianna

Este artigo analisa o texto Raça e assimilação de Oliveira Vianna, no qual o autor tentou construir um discurso científico acerca das diferenças raciais e de seu impacto na assimilação de imigrantes. Argumento que, tendo produzido textos que conferiam um papel fundamental à raça como princípio explicador dos fenômenos sociais num momento em que as abordagens racistas perdiam terreno na antropologia em favor de interpretações de tipo culturalista, Vianna desenvolveu, de forma reativa, uma argumentação cujo cerne era a defesa da cientificidade do conceito de raça como chave interpretativa da vida social. Concluo com uma leitura exploratória do diálogo que o autor estabeleceu com dois de seus contemporâneos, Arthur Ramos e Roquette-Pinto, em torno da abordagem científica exigida pelos estudos raciais e das funções político-administrativas que Vianna atribuía à ciência.<br>The present article analyzes Oliveira Vianna's text Race and assimilation, in which the author tried to build a scientific discourse on racial differences and their impact on the assimilation of immigrants. This discourse produced several texts that attributed a fundamental role to race as the cause for social phenomena at a time when anthropological racist views were falling behind due to cultural-oriented approaches. Vianna's reactive arguments were based on the defense of a scientific concept of race as the key to the interpretation of society. At the end of the article, the author analyzes the correspondence Vianna kept with Arthur Ramos and Roquette-Pinto on the scientific approaches demanded by racial studies, as well as on the political and administrative functions he attributed to science