Summary Mutations in the BANYULS (BAN) gene lead to precocious accumulation of anthocyanins in immature seed coat in Arabidopsis. The ban–1 allele has been isolated from a collection of T‐DNA transformants and found to be tagged by the integrative molecule. The sequencing of wild‐type and two independent mutant alleles confirmed the identity of the gene. Analysis of the full‐length cDNA sequence revealed an open reading frame encoding a 342 amino acid protein which shared strong similarities with DFR and other enzymes of the phenylpropanoid biosynthesis pathway. BAN expression was restricted to the endothelium of immature seeds at the pre‐globular to early globular stages of development as predicted from the maternal inheritance of the phenotype, and therefore represents a marker for early differentiation and development of the seed coat. BAN is probably involved in a metabolic channelling between the production of anthocyanins and pro‐anthocyanidins in the seed coat.

Infection with virulent strains of classical swine fever virus (CSFV) results in an acute haemorrhagic disease of pigs, characterized by disseminated intravascular coagulation, thrombocytopenia and immunosuppression, whereas for less virulent isolates infection can become chronic. In view of the haemorrhagic pathology of the disease, the effects of the virus on vascular endothelial cells was studied by using relative quantitative PCR and ELISA. Following infection, there was an initial and short-lived increase in the transcript levels of the proinflammatory cytokines interleukins 1, 6 and 8 at 3 h followed by a second more sustained increase 24 h post-infection. Transcription levels for the coagulation factor, tissue factor and vascular endothelial cell growth factor involved in endothelial cell permeability were also increased. Increases in these factors correlated with activation of the transcription factor NF-kB. Interestingly, the virus produced a chronic infection of endothelial cells and infected cells were unable to produce type I interferon. Infected cells were also protected from apoptosis induced by synthetic ouble-stranded RNA. These results demonstrate that, in common with the related pestivirus bovine viral diarrhoea virus, CSFV can actively block anti-viral and apoptotic responses and this may contribute to virus persistence. They also point to a central role for infection of vascular endothelial cells during the pathogenesis of the disease, where a proinflammatory and procoagulant endothelium induced by the virus may disrupt the haemostatic balance and lead to the coagulation and thrombosis seen in acute disease.

Classical swine fever virus (CSFV) causes severe disease in pigs associated with leukopenia, haemorrhage and fever. We show that CSFV infection protects endothelial cells from apoptosis induced by the dsRNA mimic, pIpC, but not from other apoptotic stimuli, FasL or staurosporine. CSFV infection inhibits pIpC-induced caspase activation, mitochondrial membrane potential loss and cytochrome c release as well as the pro-apoptotic effects of truncated Bid (tBid) overexpression. The CSFV proteins N pro and E rns both contribute to CSFV inhibition of apoptosis. We conclude that CSFV infection can inhibit apoptotic signalling at multiple levels, including at the caspase-8 and the mitochondrial checkpoints. By supporting viral replication, endothelial cells may promote CSFV pathogenesis. INTRODUCTIONClassical swine fever virus (CSFV), a pestivirus within the family Flaviviridae, is related in terms of its sequence and genome organization to other members of the flavivirus group that give rise to human diseases such as hepatitis C and dengue fever. CSFV is a positive-sense RNA virus, and is the causative agent of classical swine fever (CSF), a notifiable disease of pigs (Le Potier et al., 2006). Disease outbreaks are associated with considerable economic loss and adverse effects on animal welfare (Paton & GreiserWilke, 2003). In its most virulent form, CSFV infection causes severe immunopathological signs, including leukopenia, haemorrhage and fever, accompanied by high morbidity and mortality. However, within an infected population, some animals are found to recover or develop chronic disease (Le Potier et al., 2006). These observations suggest a complex interplay between the virus and the host immune system. CSFV infection is accompanied by depression of cellular immune defences (Ganges et al., 2008) and particularly innate responses mediated by interferon (Bensaude et al., 2004; La Rocca et al., 2005; Ruggli et al., 2005;Seago et al., 2007). In vivo, elevated levels of cell death by apoptosis are thought to account for the characteristic depletion of circulating leukocytes (Sanchez-Cordon et al., 2002;Summerfield et al., 2000Summerfield et al., , 2001. However, it has been found that apoptotic cells rarely contain detectable viral antigen, indicating that apoptotic cells are generally not CSFV-infected (Choi et al., 2004;Sato et al., 2000;Summerfield et al., 2001). This finding, together with the observation that acutely infected animals develop high viral loads, suggest a possible role for cell populations that are resistant to virus-induced apoptosis. These may include endothelial cells.Apoptosis is a controlled cell death programme employed by multicellular organisms to eliminate damaged, aberrant or infected cells (Benedict et al., 2002). A characteristic of apoptotic cell death is the activation of the caspase family of proteases. Caspases that function near the apex of cell death cascades are designated initiators and include caspases-8 and -9, whereas those involved in the terminal stages of cell death, such as ...

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Bovine viral diarrhoea virus (BVDV) infection of cattle causes a diverse range of clinical outcomes from being asymptomatic, or a transient mild disease, to producing severe cases of acute disease leading to death. Four groups of calves were challenged with a type 1 BVDV strain, originating from a severe outbreak of BVDV in England, to study the effect of viral dose and immunosuppression on the viral replication and transmission of BVDV. Three groups received increasing amounts of virus: Group A received 102.55TCID50/ml, group B 105.25TCID50/ml and group C 106.7TCID 50/ml. A fourth group (D) was inoculated with a medium dose (105.25TCID50/ml) and concomitantly treated with dexamethasone (DMS) to assess the effects of chemically induced immunosuppression. Naïve calves were added as sentinel animals to assess virus transmission. The outcome of infection was dose dependent with animals given a higher dose developing severe disease and more pronounced viral replication. Despite virus being shed by the low-dose infection group, BVD was not transmitted to sentinel calves. Administration of dexamethasone (DMS) resulted in more severe clinical signs, prolonged viraemia and virus shedding. Using PCR techniques, viral RNA was detected in blood, several weeks after the limit of infectious virus recovery. Finally, a recently developed strand-specific RT-PCR detected negative strand viral RNA, indicative of actively replicating virus, in blood samples from convalescent animals, as late as 85 days post inoculation. This detection of long term replicating virus may indicate the way in which the virus persists and/or is reintroduced within herds.