Prospecção de vírus gigantes em ostras e água do mar

Abstract

Viruses are ubiquitous organisms found in any environment in which life is present. They are known as ultramicroscopic agents, obligatory intracellular parasites and dependent on the host cellular machinery for their multiplication. However, in recent decades, a monophyletic group of viruses, extremely diverse and complex, with an extraordinary structural and genomic range, came to the scientific forefront, raising questions about the origin and nature of viruses. This group is known as the nucleocytoplasmic large DNA viruses (NCLDV), and comprise the recently proposed order Megavirales. In the 2000s, the characterization of an extremely complex virus put in question everything that was known about viruses. This virus, named Acanthamoeba polyphaga mimivirus, was placed into its viral own family, Mimiviridae, not fitting to any existing family. Furthermore, several additional giant viruses have been isolated from different environments and specimens. In this context, the aim of this study was to evaluate the incidence of isolated mimivirus in samples of oysters and sea water collected in three brazilian coastal regions. We used techniques of samples enrichment for subsequent isolation in cell monolayers species of Acanthamoeba castellanii. For biological characterization of new isolates we used electron microscopy transmission and assays of stress when exposed to ultraviolet light and temperature, and we used molecular techniques to evaluate the molecular profile of each isolate. Four new isolates have been characterized biological and molecularly in which it was possible to observe viral particles similar to viruses belonging to the family Mimiviridae and possible biological and / or structural differences after exposure to the stress tests. The new isolates belong to the group A Mimiviridae family. Our results also suggest that oysters are an excellent source for the isolation of giant viruses.