Estudos de prospecção, caracterização e ensaios sorológicos de vírus gigantes: analisando amostras ambientais brasileiras, soros de humanos e outros vertebrados

• Ano de defesa: 2016
• Autor(a) principal: Fábio Pio Dornas
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ICB - DEPARTAMENTO DE MICROBIOLOGIA; Programa de Pós-Graduação em Microbiologia; UFMG
• Palavras-chave em Português: Mimivírus; Marseillevírus; Pandoravírus; Isolamento viral; Ensaios sorológicos; Vertebrados; Microbiologia; Mimiviridae; Vírus/isolamento & purificação; Testes Sorológicos
• Link de acesso: http://hdl.handle.net/1843/42542; https://orcid.org/0000-0001-7926-5551

The giant viruses have been grouped into the proposed order Megavirales due to particulars biological and phylogenetic characteristics. Exclusive characteristics have been described, supporting new studies about the biology and circulation of giant viruses. The objective of this work was to analyze the distribution and circulation of giant viruses by approaches involving the prospection in environmental samples and characterization of new isolates and by analyzing the presence of neutralizing antibodies and viral DNA in vertebrates sera samples (humans, bovines and non-human primates). These studies were divided in two sections. The first involving analysis of environmental samples collected from lake around Belo Horizonte city, Minas Gerais state. The amoebas’ species Acanthamoeba spp. and Vermamoeba vermiformis were used as cellular systems for viral isolation assays. Viral characterization, was done by biological and molecular assays. For the second section, sera samples were analyzed by viral neutralizing assays and by PCR and sequencing of mimiviral genes. We report the isolation of 70 new giant viruses in this studyMimivirus lineages B and C were first reported in Brazilian environmental samples, as well as news isolates of marseillevirus and pandoravirus. One new mimivirus lineage A, named Kroon virus, was characterized. Regarding serological analysis, and considering the different sera collections, we observed positivity ranging from 4.7% to 31.6% in neutralizing assays and 8.5% to 42.1% for mimiviral DNA detection. A number of polymorphisms were observed in mimivirus sequences amplified from sera samples, even considering conserved viral genes. However, the biological mean of the detection of antibodies-against mimivirus and mimivirus DNA in vertebrates remains to be investigated. Taken together, the dataset presented in this work demonstrate the active circulation of giant viruses in Brazilian territory and suggest that the analyzed vertebrate’s species are under explosion to those viruses.