Spontaneous mutagenesis of a plant potyvirus genome after insertion of a foreign gene.

The RNA genome of tobacco etch potyvirus (TEV) was engineered to express bacterial 13-glucuronidase (GUS) fused to the virus helper component proteinase (HC-Pro). It was shown previously that prolonged periods (-1 month) of TEV-GUS propagation in plants resulted in the appearance of spontaneous deletion variants. Nine deletion mutants were identified by nucleotide sequence analysis of 40 cDNA clones obtained after polymerase chain reaction amplification. The mutants were missing between 1,741 and 2,074 nucleotides from TEV-GUS, including the sequences coding for most of GUS and the N-terminal region of HC-Pro. This region of HC-Pro contains determinants involved in helper component activity during aphid transmission, as well as a highly conserved series of cysteine residues. The deletion variants were shown to replicate and move systemically without the aid of a helper virus. Infectious viruses harboring the two largest HC-Pro deletions (termed TEV-2del and TEV-7del) were reconstructed by subcloning the corresponding mutated regions into full-length DNA copies of the TEV genome. Characterization of these and additional variants derived by site-directed mutagenesis demonstrated that deletion of sequences coding for the HC-Pro N-terminal domain had a negative effect on accumulation of viral RNA and coat protein. The TEV-2del variant possessed an aphid-nontransmissible phenotype that could be rescued partially by prefeeding of aphids on active HC-Pro from another potyvirus. These data suggest that the N-terminal domain of HC-Pro or its coding sequenc

Patient safety and sociotechnical considerations for electronic handover tools in an Australian ehealth landscape

The Australian Commission for Safety and Quality in Health Care (ACSQHC) coordinates national improvements in a range of complex health system problems including clinical handover, and has funded a range of handover improvement projects in Australia. One of these, the SafeTECH project in South Australia has developed guidelines for safe use of electronic handover tools. These guidelines were developed using evidence from three hospital case studies into theuse of an electronic tool to support different types of shift-to-shift handover. This paper provides an overview of the project, and highlights challenges for patient safety in the design and use of electronic tools to support clinical handover in a busy clinical environment. The paper then considers these challenges within the broader context of the Australian ehealth landscape. Australia’s National eHealth Transition Authority (NEHTA) is actively developing ehealth standards and infrastructure requirements for the electronic collection and secure exchange of health information. The paper argues for flexible standardisation in the design and implementation of electronic handover tools to ensure that all key dimensions of the challenges faced in ensuring patient safety are addressed