RESUMO
Oyster production is an economic activity of great interest worldwide. Recently, oysters have been suffering significant mortalities from OsHV-1infection, which has resulted in substantial economic loses in several countries around the world. Understanding viral pathogenicity mechanisms is of central importance for the establishment of disease control measures. Thus, the present work aimed to identify and characterize miRNAs from OsHV-1 as well as to predict their target transcripts in the virus and the host. OsHV-1 genome was used for the in silico discovery of pre-miRNAs. Subsequently, viral and host target transcripts of the OsHV-1 miRNAs were predicted according to the base pairing interaction between mature miRNAs and mRNA 3' untranslated regions (UTRs). Six unique pre-miRNAs were found in different regions of the viral genome, ranging in length from 85 to 172 nucleotides. A complex network of self-regulation of viral gene expression mediated by the miRNAs was identified. These sequences also seem to have a broad ability to regulate the expression of host immune-related genes, especially those associated with pathogen recognition. Our results suggest that OsHV-1 encodes miRNAs with important functions in the infection process, inducing self-regulation of viral transcripts, as well as affecting the regulation of Pacific oyster transcripts related to immunity. Understanding the molecular basis of host-pathogen interactions can help mitigate the recurrent events of oyster mass mortalities by OsHV-1 observed worldwide.
Assuntos
Crassostrea/virologia , Vírus de DNA/patogenicidade , Interações Hospedeiro-Patógeno/genética , MicroRNAs/metabolismo , RNA Viral/metabolismo , Animais , Aquicultura , Biologia Computacional , Crassostrea/genética , Crassostrea/imunologia , Vírus de DNA/genética , Vírus de DNA/imunologia , Regulação da Expressão Gênica/imunologia , Redes Reguladoras de Genes/genética , Redes Reguladoras de Genes/imunologia , Interações Hospedeiro-Patógeno/imunologia , MicroRNAs/genética , MicroRNAs/isolamento & purificação , RNA Viral/genética , RNA Viral/isolamento & purificaçãoRESUMO
The present study compares 13 physiological and immunological variables between a group of healthy Panulirus argus lobsters and a group of lobsters naturally infected with Panulirus argus Virus 1 (PaV1). Viral infection was determined through histopathology and PCR. Ten of the 13 variables differed significantly between the 2 groups. Using these variables, a principal component analysis yielded 2 separate clusters: one corresponding to the healthy group and the other corresponding to the infected group. In particular, infected lobsters exhibited significantly lower levels of osmotic pressure, total hemocyte counts, plasmatic proteins, and total phenoloxidase (PO) activity in plasma, as well as significantly higher levels of cholesterol and acylglycerides. These features are consistent with metabolic wasting, hyperlipidemia, and presumed immune suppression. Infection with PaV1 appears to increase the susceptibility of lobsters to some other opportunistic pathogens, as 61.1% of infected lobsters presented infestations of ciliate epibionts (Epystilis and Zoothamniun) in the gill chamber compared with 11.5% lobsters in the healthy group. Infected lobsters also showed significantly higher levels of total PO activity in degranulated hemocytes and trypsin inhibitor activity, potentially indicating activation of immune response by the PO system during the systemic infection with PaV1.
Assuntos
Vírus de DNA/isolamento & purificação , Palinuridae/fisiologia , Palinuridae/virologia , Animais , Vírus de DNA/imunologia , Análise Multivariada , Palinuridae/imunologia , Reação em Cadeia da PolimeraseRESUMO
Antibody responses to bacteriophage phichi 174 were studied in 17 institutionalized patients with trisomy 21 and in six mentally retarded control patients with normal karyotype. Primary antibody response was significantly impaired in 11 of the 17 patients. Secondary immune response was normal in one, moderately impaired in seven, and very low in nine patients. Tertiary immunization further differentiated the two groups: those with moderately impaired secondary immune responses developed normal serum titers of predominantly IgG antibody; patients with low secondary immune responses had extemely impaired tertiary immune responses consisting mainly of serum IgM antibody.