Existe atividade transcricional durante o fenômeno de persistência nucleolar na meiose dos triatomíneos?
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Data
2017-03-02
Autores
Madeira, Fernanda Fernandez [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os triatomíneos são insetos hematófagos de grande importância para a saúde pública, uma vez que são considerados como a principal forma de transmissão do protozoário Trypanosoma cruzi, agente etiológico da doença de Chagas. Além da importância epidemiológica, esses insetos se destacam em estudos celulares, pois apresentam algumas peculiaridades, como cromossomos holocêntricos, meiose invertida para os cromossomos sexuais e persistência nucleolar durante a meiose. O fenômeno de persistência nucleolar é definido pela presença do nucléolo ou corpúsculos nucleolares durante todas as fases da meiose. Esse fenômeno foi descrito, até o momento, para 24 espécies de triatomíneos, dos gêneros Triatoma, Rhodnius e Panstrongylus. No entanto, somente a presença dessa estrutura nuclear em todas as fases da meiose não garante a sua atividade transcricional. Diante disso, o presente estudo teve como objetivo descrever a nucleologênese em novas espécies de, pelo menos, sete novos gêneros (Cavernicola, Psammolestes, Dipetalogaster, Eratyrus, Meccus, Mepraia, Nesotriatoma), com o intuito de analisar se a persistência nucleolar é uma sinapomorfia da subfamília Triatominae. Além disso, esse trabalho também teve como finalidade avaliar a atividade nucleolar durante a meiose das espécies Triatoma infestans, Rhodnius montenegrensis e Panstrongylus megistus, por meio da técnica citoquímica Acridine Orange, com o objetivo de caracterizar, com base na presença de RNA, se existe atividade transcricional do material nucleolar persistente. Todas as 59 espécies analisadas, distribuídas em sete gêneros, apresentaram persistência nucleolar durante a meiose, corroborando, portanto, que esse fenômeno é uma sinapomorfia da subfamília Triatominae. Por meio do fluorocromo Acridine Orange, foi verificado que o nucléolo persistente apresenta-se transcricionalmente ativo. Dessa forma, evidencia-se, pela primeira vez, que o nucléolo está presente na espermatogênese de todos os triatomíneos e que esse material apresenta-se transcricionalmente ativo, suportando a relação entre a persistência nucleolar durante a meiose desses insetos e a formação da organela corpo cromatóide.
Triatomines are hematophagous insects of great importance for public health, since they are considered as the main form of transmission of the protozoan Trypanosoma cruzi, etiologic agent of Chagas disease. Besides the epidemiological importance, these insects stand out in cellular studies, as they present some peculiarities, such as holocentric chromosomes, inverted meiosis for sex chromosomes and nucleolar persistence during meiosis. The phenomenon of nucleolar persistence is defined by the presence of the nucleolus or nucleolar corpuscles during all phases of meiosis. So far, this phenomenon has been described for 24 triatomine species of the genus Triatoma, Rhodnius and Panstrongylus. However, only the presence of this nuclear structure in all phases of meiosis does not guarantee its transcriptional activity. So, the objective of the present study was to describe the nucleologenesis in new species of at least seven new genera (Cavernicola, Psammolestes, Dipetalogaster, Eratyrus, Meccus, Mepraia, Nesotriatoma), in order to analyze if nucleolar persistence is a synapomorphy of the subfamily Triatominae. Besides that, this work had the purpose to evaluate the nucleolar activity during the meiosis of the species Triatoma infestans, Rhodnius montenegrensis and Panstrongylus megistus, by means of the cytochemical technique Acridine Orange, with the objective of characterizing, based on the presence of RNA, if there is transcriptional activity in the persistent nucleolar material. All 59 species analyzed, distributed in seven genera, presented nucleolar persistence during meiosis, thus corroborating that this phenomenon is a synapomorphy of the subfamily Triatominae. By means of the fluorochrome Acridine Orange, the persistent nucleolus has been found to be transcriptionally active. Thus, it was evident, for the first time, that the nucleolus is present in the spermatogenesis of all triatomines and that this material is transcriptionally active, supporting the relationship between nucleolar persistence during the meiosis of these insects and the formation of the organelle chromatoid body.
Triatomines are hematophagous insects of great importance for public health, since they are considered as the main form of transmission of the protozoan Trypanosoma cruzi, etiologic agent of Chagas disease. Besides the epidemiological importance, these insects stand out in cellular studies, as they present some peculiarities, such as holocentric chromosomes, inverted meiosis for sex chromosomes and nucleolar persistence during meiosis. The phenomenon of nucleolar persistence is defined by the presence of the nucleolus or nucleolar corpuscles during all phases of meiosis. So far, this phenomenon has been described for 24 triatomine species of the genus Triatoma, Rhodnius and Panstrongylus. However, only the presence of this nuclear structure in all phases of meiosis does not guarantee its transcriptional activity. So, the objective of the present study was to describe the nucleologenesis in new species of at least seven new genera (Cavernicola, Psammolestes, Dipetalogaster, Eratyrus, Meccus, Mepraia, Nesotriatoma), in order to analyze if nucleolar persistence is a synapomorphy of the subfamily Triatominae. Besides that, this work had the purpose to evaluate the nucleolar activity during the meiosis of the species Triatoma infestans, Rhodnius montenegrensis and Panstrongylus megistus, by means of the cytochemical technique Acridine Orange, with the objective of characterizing, based on the presence of RNA, if there is transcriptional activity in the persistent nucleolar material. All 59 species analyzed, distributed in seven genera, presented nucleolar persistence during meiosis, thus corroborating that this phenomenon is a synapomorphy of the subfamily Triatominae. By means of the fluorochrome Acridine Orange, the persistent nucleolus has been found to be transcriptionally active. Thus, it was evident, for the first time, that the nucleolus is present in the spermatogenesis of all triatomines and that this material is transcriptionally active, supporting the relationship between nucleolar persistence during the meiosis of these insects and the formation of the organelle chromatoid body.
Descrição
Palavras-chave
Nucléolo, Ciclo nucleolar, Triatomíneos, Citoquímica, Corpo cromatóide, Nucleolus, Nucleolar cycle, Triatomine, Cytochemistry, Chromatoid body