O isolamento e a caracterização de um novo isolado brasileiro de mimivírus da linhagem C suscita questões acerca da estrutura das fibrilas das linhagens A, B e C de mimivírus

Abstract

The description of the first giant amoeba virus in 2003, Acanthamoeba polyphaga mimivirus (APMV), spurred researchers around the world to not only search for other giant viruses, but also to deepen their studies on the APMV. Thus, the group of Large Nucleocytoplasmic DNA Viruses (NCLDV), to which these viruses currently belong, has become increasingly diversified. Although mimiviruses were the first to be described, and consequently the most studied so far, many gaps in knowledge about the biology, phylogenetic relationships and taxonomy of these viruses still need to be filled and elucidated. In addition to gene-based phylogenetic inferences, in this work we propose that fibril morphology may be evidence of the division of mimiviruses into three different lineages. Using methodologies such as prospecting and in silico analysis to assess electron microscopy images using computer tools and to construct phylogenetic analysis, we describe a new Brazilian isolate of mimivirus belonging to the C lineage, as well as study further, seeking evidence to support the division of mimiviruses within lineages A, B and C. We observed that there are not only genomic differences among the lineage A, B and C mimiviruses, but also morphological differences between the fibrils present in the viral particles. These discoveries help both in classification and taxonomy, as well as in the construction of knowledge about the biology of mimivirus particles, which can even improve their identification already during isolation and also allow the understanding of their ecology and relationship with the host, since fibrils are important elements for mimiviruses to be able to adhere to the host amoeba and initiate the infection.