Saffold Virus, a Human Theiler's-Like Cardiovirus, Is Ubiquitous and Causes Infection Early in Life

The family Picornaviridae contains well-known human pathogens (e.g., poliovirus, coxsackievirus, rhinovirus, and parechovirus). In addition, this family contains a number of viruses that infect animals, including members of the genus Cardiovirus such as Encephalomyocarditis virus (EMCV) and Theiler's murine encephalomyelits virus (TMEV). The latter are important murine pathogens that cause myocarditis, type 1 diabetes and chronic inflammation in the brains, mimicking multiple sclerosis. Recently, a new picornavirus was isolated from humans, named Saffold virus (SAFV). The virus is genetically related to Theiler's virus and classified as a new species in the genus Cardiovirus, which until the discovery of SAFV did not contain human viruses. By analogy with the rodent cardioviruses, SAFV may be a relevant new human pathogen. Thus far, SAFVs have sporadically been detected by molecular techniques in respiratory and fecal specimens, but the epidemiology and clinical significance remained unclear. Here we describe the first cultivated SAFV type 3 (SAFV-3) isolate, its growth characteristics, full-length sequence, and epidemiology. Unlike the previously isolated SAFV-1 and -2 viruses, SAFV-3 showed efficient growth in several cell lines with a clear cytopathic effect. The latter allowed us to conduct a large-scale serological survey by a virus-neutralization assay. This survey showed that infection by SAFV-3 occurs early in life (>75% positive at 24 months) and that the seroprevalence reaches >90% in older children and adults. Neutralizing antibodies were found in serum samples collected in several countries in Europe, Africa, and Asia. In conclusion, this study describes the first cultivated SAFV-3 isolate, its full-length sequence, and epidemiology. SAFV-3 is a highly common and widespread human virus causing infection in early childhood. This finding has important implications for understanding the impact of these ubiquitous viruses and their possible role in acute and/or chronic disease

Sensitive DNA electrical detection based on interdigitated Al/Al2O3 microelectrodes

The detection of DNA by electrical based methods still faces the challenge of the low amounts of genetic material to be analyzed in order to make the assay useful for biological applications. In this work we present the possibility of detecting DNA strands by measuring a change of capacitance between interdigitated electrodes, of 1, 2 and 3 mum widths and spacing, made of aluminum fingers, coated with a thin alumina layer and constructed over an oxidized silicon wafer, reducing the non-specific precipitation of silver that occurs when using noble metal electrodes like gold. Labeling of DNA was performed by incorporation of biotinylated nucleotides and reaction with anti-biotin antibodies coupled to gold nanoparticles, whose size was increased by silver crystal precipitation. We observed a change in capacitance by a factor of at least two, using DNA solutions down to 0.2 nM, spotted on the electrodes. This method of detection thus appears compatible with the requirements of microarray technology and paves the way for further use in biological applications. (C) 2003 Elsevier B.V. All rights reserved

Immobilization of DNA on CMOS compatible materials

The main interface and interconnection materials normally used in complementary metal-oxide semiconductor (CMOS) integrated circuit processing, i.e. silicon oxides and aluminum, were evaluated with regards to deoxyribonucleic acid (DNA) attachment. We investigated and quantified the influence of various techniques of fabrication of the silicon oxide on DNA binding obtained by four different biochemical processes. Regarding aluminum, we found that it only binds DNA in the presence of its natural oxide and that it is severely degraded by one of the three typical biochemical processes. Optimal process conditions for DNA binding on silicon oxides with aluminum compatibility are finally derived. (C) 2003 Elsevier Science B.V. All rights reserved

Phylogenetics, population structure and genetic diversity of the endangered southern brown bandicoot (Isoodon obesulus) in south-eastern Australia

The southern brown bandicoot (Isoodon obesulus) has undergone significant range contractions since European settlement, and it is now considered "Endangered" throughout south-eastern mainland Australia. This species currently has a highly fragmented distribution inhabiting a mosaic of habitats. This project uses mitochondrial DNA (mtDNA) and microsatellite data to determine levels of genetic diversity, population structure and evolutionary history, which can aid wildlife managers in setting priorities and determining management strategies. Analyses of genetic diversity revealed low levels of mtDNA variability (mean h=50.42%, π=0.76%) and divergence (mean dA=0.29%) across all regions investigated, and was among the lowest recorded for marsupials. These data indicate a relatively small female effective population size, which is most likely a consequence of a large-scale population contraction and subsequent expansion occurring in pre-history (mismatch distribution analysis, SSD P-value=0.12). Individuals from the Sydney region experienced significant reductions in microsatellite diversity (A=3.8, HE=0.565), with the Garigal National Park (NP) population exhibiting "genetic reduction signatures" indicating a recent population bottleneck. Population differentiation analysis revealed significant genetic division amongst I. obesulus individuals from Sydney, East Gippsland and Mt Gambier regions (theta=0.176–0.271), but could not separate the two Sydney populations (Ku-ring-gai NP and Garigal NP). Based on these data and habitat type, translocations could readily be made between the two Sydney populations, but not between the others. Phylogenetic comparisons between I. obesulus and I. auratus show little support for current Isoodon taxonomy, consistent with the findings of Pope et al. 2001. We therefore recommend the recognition of only three I. obesulus sub-species and suggest that these comprise a single morphologically diverse species that once was widespread across Australia

Delivery of mengovirus-derived RNA replicons into tumoural liver enhances the anti-tumour efficacy of a peripheral peptide-based vaccine.

International audienceHepatocellular carcinoma is a deadly cancer with growing incidence for which immunotherapy is one of the most promising therapeutic approach. Peptide-based vaccines designed to induce strong, sustained CD8+ T cell responses are effective in animal models and cancer patients. We demonstrated the efficacy of curative peptide-based immunisation against a unique epitope of SV40 tumour antigen, through the induction of a strong CD8+ T cell-specific response, in our liver tumour model. However, as in human clinical trials, most tumour antigen epitopes did not induce a therapeutic effect, despite inducing strong CD8+ T cell responses. We therefore modified the tumour environment to enhance peptide-based vaccine efficacy by delivering mengovirus (MV)-derived RNA autoreplicating sequences (MV-RNA replicons) into the liver. The injection of replication-competent RNA replicons into the liver converted partial tumour regression into tumour eradication, whereas non-replicating RNA had no such effect. Replicating RNA replicon injection induced local recruitment of innate immunity effectors (NK and NKT) to the tumour and did not affect specific CD8+ T cell populations or other myelolymphoid subsets. The local delivery of such RNA replicons into tumour stroma is therefore a promising strategy complementary to the use of peripheral peptide-based vaccines for treating liver tumours