Programmed -1 ribosomal frameshifting is a mechanism of gene expression whereby specific signals within messenger RNAs direct a proportion of ribosomes to shift -1 nt and continue translating in the ...new reading frame. Such frameshifting normally depends on an RNA structure stimulator 3'-adjacent to a 'slippery' heptanucleotide shift site sequence. Recently we identified an unusual frameshifting mechanism in encephalomyocarditis virus, where the stimulator involves a trans-acting virus protein. Thus, in contrast to other examples of -1 frameshifting, the efficiency of frameshifting in encephalomyocarditis virus is best studied in the context of virus infection. Here we use metabolic labelling to analyse the frameshifting efficiency of wild-type and mutant viruses. Confirming previous results, frameshifting depends on a G_GUU_UUU shift site sequence and a 3'-adjacent stem-loop structure, but is not appreciably affected by the 'StopGo' sequence present ~30 nt upstream. At late timepoints, frameshifting was estimated to be 46-76 % efficient.
To manage extensive walking track (trail) systems effectively, managers need information about the condition, stability and likely rates of deterioration of tracks. This information may be ...impractical to obtain from ground inspections, particularly if the track systems of interest encompass hundreds or even thousands of kilometres of tracks. Two trials were undertaken in Tasmania, Australia to assess the practicality of using a GIS-based methodology to predict track ‘types’, types being classes of environmental and track-orientation variables that are associated with characteristic rates of widening and erosion as tracks develop. In the first trial, type values previously measured at 500 18 m long monitoring sites located across a wide range of environments were compared with those predicted for 50–75 m long track segments that included or overlapped the sites. In the second trial, the type values of 300 75 m track segments distributed across five tracks were measured in the field and predicted using a refined version of the methodology. The reliability of the methodology was slightly improved in the second trial, in which 50% of the predictions were accurate and 38% were out by one category. Predictions of the statistical distribution of types were prone to bias due to local conditions on individual tracks, but agreed closely with the measured distribution across the entire data set. The methodology was used to assess track types across the 1700 km track system managed by the Tasmanian Parks and Wildlife Service, as a basis for identifying and prioritising management responses including track stabilisation works. It is likely that with further refinement and with better GIS information, the methodology could reliably predict the stability of individual tracks.
► A GIS-based methodology is proposed for predicting walking track stability ‘types’. ► The reliability of the methodology was tested across a wide range of environments. ► The statistical distribution of types is predicted reliably for extensive track systems. ► The methodology is useful in planning management responses such as track ‘hardening’. ► The methodology was used to assess types across a 1700 km track system in Tasmania.
Reviews "Zeugma I : fouilles de l'habitat : la mosaïque de Pasiphae" ("Zeugma I : excavations of the residence : the mosaic of Pasiphae") edited by Catherine Abadie-Reynal, Rifat Ergeç (De Boccard, ...2012).
Reviews "Amphorenträger im Treppenhaus : zur Architektur und Wanddekoration der Gebäude in Insula 39 von Augusta Raurica" ("Amphorae carriers in the stairway : on the architecture and mural ...decoration of the buildings of Insula 39 at Augusta Raurica"), by Thomas Hufschmid and Lucile Tissot-Jordan (2013).
Clostridium botulinum neurotoxin type A is a potently toxic protein of 150 kDa with specific endopeptidase activity for the SNARE protein SNAP-25. Proteolytic cleavage of BoNT/A with trypsin leads to ...removal of the C-terminal domain responsible for neuronal cell binding. Removal of this domain result in a catalytically active, non-cell-binding derivative termed LH
N/A. We have developed a purification scheme to prepare LH
N/A essentially free of contaminating BoNT/A. LH
N/A prepared by this scheme retains full enzymatic activity, is stable in solution, and is of low toxicity as demonstrated in a mouse toxicity assay. In addition, LH
N/A has minimal effect on release of neurotransmitter from a primary cell culture model. Both the mouse bioassay and in vitro release assay suggest BoNT/A is present at less than 1 in 10
6 molecules of LH
N/A. This represents a significant improvement on previously reported figures for LH
N/A, and also the light chain domain, previously purified from BoNT/A. To complement the preparation of LH
N/A from holotoxin, DNA encoding LH
N/A has been introduced into
Escherichia coli to facilitate expression of recombinant product. Expression and purification parameters have been developed to enable isolation of soluble, stable endopeptidase with a toxicity profile enhanced on that of LH
N/A purified from BoNT/A. The recombinant-derived material has been used to prepare antisera that neutralise a BoNT/A challenge. The production of essentially BoNT/A-free LH
N/A by two different methods and the possibilities for exploitation are discussed.
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