Subcellular redistribution and sequential recruitment of macromolecular components during SGIV assembly

Virus infection consists of entry, synthesis of macromolecular components, virus assembly and release. Understanding of the mechanisms underlying each event is necessary for the intervention of virus infection in human healthcare and agriculture. Here we report the visualization of Singapore grouper iridovirus (SGIV) assembly in the medaka haploid embryonic stem (ES) cell line HX1. SGIV is a highly infectious DNA virus that causes a massive loss in marine aquaculture. Ectopic expression of VP88GFP, a fusion between green fluorescent protein and the envelope protein VP088, did not compromise the ES cell properties and susceptibility to SGIV infection. Although VP88GFP disperses evenly in the cytoplasm of non-infected cells, it undergoes aggregation and redistribution in SGIV-infected cells. Real-time visualization revealed multiple key stages of VP88GFP redistribution and the dynamics of viral assembly site (VAS). Specifically, VP88GFP entry into and condensation in the VAS occurred within a 6-h duration, a similar duration was observed also for the release of VP88GFP-containing SGIV out of the cell. Taken together, VP088 is an excellent marker for visualizing the SGIV infection process. Our results provide new insight into macromolecular component recruitment and SGIV assembly.

Inverse PCR amplification of the complete major capsid protein gene of lymphocystis disease virus isolated from Rachycentron canadum and the phylogenetic analysis of the virus / 病毒学报

The major capsid protein of lymphocystis disease virus isolated from Rachycentron canadum (LCDV-rc) was amplified and analysed. The 457bp DNA core fragment was amplified with the degenerate primers designed according to the conserved sequences of MCP gene of iridoviruses, then the flaking sequences adjacent to the core region were amplified by inverse PCR, and the complete sequence was obtained by combining all of them. The open reading frame of the gene is 1380bp in length, encoding a putative protein of 459 aa with molecular weight 51.12 kD and pI 6.87. Constructing the phylogenetic tree for comparing the MCP amino acid of iridoviruses, the results indicated that LCDV-rc is most homologous to the other Lymphocystis viruses and all of them constitute a branch. Accordingly LCDV-rc is identified as Lymphocystivirus.

Controle microbiano natural de populaçoës de paquinhas (Orthoptera: Gryllotalpidae: Scapteriscus borellii): regulaçäo de populaçoës agregadas no tempo e no espaço / Natural microbial control of crickets populations (Orthoptera: Gryllotalpidae: Scapteriscus borellii): regulations aggregated in time and space

Durante levantamentos realizados de 1983 a 1988, um total de 1.762 coletas, totalizando 3.312 indivíduos da paquinha, Scapteriscus borellii, foram feitas, principalmente no Estado de Säo Paulo, Brasil. As coletas ajustavam-se bem na totalidade, a uma distribuiçäo binomial negativa e também quando decomposta a coletas mensais. Das coletas, um iridovirus, um nematóide entomogênico, e os fungos Metarhizium anisopliae, Beauveria bassiana, Paecilomyces sp., Aspergillus sp., Sorsporella sp., e Entomophtora sp., foram encontrados como agentes de mortalidade natural, ainda que como endozoóticos e relativamente rara como epizoóticos ou panzoóticos. Como um conjunto, as doenças também foram distribuídas em forma binomial negativa. Estes dados implicam que as agregaçöes temporais e espaciais das paquinhas, determinadas por taxas elevadas de migraçäo entre habitats apropriados, säo respostas para enfrentar os surtos de doenças que também servem como reguladoras dos níveis populacionais da paquinha. Essas idéias säo desenvolvidas e derivadas de modelos matemáticos simples de mudanças de populaçöes