Banca de QUALIFICAÇÃO: MÁRCIA DANIELLE DE ARAÚJO DANTAS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : MÁRCIA DANIELLE DE ARAÚJO DANTAS
DATA : 26/02/2018
HORA: 14:00
LOCAL: Sala Carl Peter von Dietrich - Departamento de Bioquímica
TÍTULO:

Study of the Genomes of the Major Viruses Acquiring the Carcinculture of the State of Rio Grande do Norte

PALAVRAS-CHAVES:

IMNV, WSSV, PstDNV, Phylogeny, Shrimp

PÁGINAS: 106
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

The northeast region is one of the largest shrimp producers in Brazil, with emphasis on the states of Ceará and Rio Grande do Norte. One of the biggest problems that Universidade Federal do Rio Grande do Norte Centro de Biociências Departamento de Bioquímica Programa de Pós-Graduação em Bioquímica the shrimp industry has been facing in recent decades is the increased incidence of infectious diseases. Among these diseases, those caused by White spot syndrome virus (WSSV), Infectious hypodermal and haematopoietic necrosis virus (PstDNV) and Infectious myonecrosis virus (IMNV) cost billions of dollars in shrimp farming and the social and economic impacts have been profound in countries where this activity is a significant industry. The study of these viruses’s genomes is of fundamental importance to understand mechanisms essential to their survival and, thus, to develop effective tools for detection and control. In this context, the general objective of this work was to study the IMNV, WSSV and PstDNV genomes and to contribute with new information on the biology of these pathogens. Chapter 1 describes the study of sequences of the Totiviridae family members. The amino acid alignment of ORF1 indicates that the artiviruses are the only members of the Totiviridae family that have the 2A-like cleavage sites and two proteins previously predicted for the IMNV. A possible site of cleavage upstream to the capsid protein has also been identified in these genomes. Protein models revealed conserved structures for the two proteins, indicating that they are probably involved in the formation of viral protrusions and RNA packaging. Chapter 2 addresses the sequencing and analysis of the first genome of a Brazilian WSSV isolate (WSSVBR). The genome was sequenced using the Ion Torrent platform and assembled using an alternate pipeline in which a WSSV chimera genome was used as the reference sequence. The genome had a size of 292,912 bp, 184 possible ORFs and nine homologous regions (hrs). Identity and phylogenetic analyzes have shown that Brazilian WSSV is closer to isolates from Thailand and Mexico and that probably these three viruses share a common evolutionary origin. In addition, it has been noted that the WSSV evolutionary history may be related to recombination events and that these events, somehow, can be traced by analyzing the homologous regions of WSSV. Chapter 3, which is in progress, discusses about the sequencing and analysis of a possible new Brazilian variant of PstDNV (PstDNV-BR17), which does not cause symptoms in shrimps. The identity comparison and phylogenetic analysis showed that the new isolate was part of the PstDNV infectious lineage, which was unexpected. Secondary and tertiary structure analyzes of viral proteins also did not show differences among Brazilian isolates. It is possible that shrimp are becoming resistant to the PstDNV. All these results together contribute to increase the knowledge about the main viruses that affect the global shrimp farming.

MEMBROS DA BANCA:
Externo ao Programa - 1715230 - JOSELIO MARIA GALVAO DE ARAUJO
Interno - 2275890 - MARCELO DE SOUSA DA SILVA
Presidente - 1199127 - SILVIA REGINA BATISTUZZO DE MEDEIROS