XSophe-Sophe-XeprView (R). A computer simulation software suite (v. 1.1.3) for the analysis of continuous wave EPR spectra

The XSophe-Sophe-XeprView((R)) computer simulation software suite enables scientists to easily determine spin Hamiltonian parameters from isotropic, randomly oriented and single crystal continuous wave electron paramagnetic resonance (CW EPR) spectra from radicals and isolated paramagnetic metal ion centers or clusters found in metalloproteins, chemical systems and materials science. XSophe provides an X-windows graphical user interface to the Sophe programme and allows: creation of multiple input files, local and remote execution of Sophe, the display of sophelog (output from Sophe) and input parameters/files. Sophe is a sophisticated computer simulation software programme employing a number of innovative technologies including; the Sydney OPera HousE (SOPHE) partition and interpolation schemes, a field segmentation algorithm, the mosaic misorientation linewidth model, parallelization and spectral optimisation. In conjunction with the SOPHE partition scheme and the field segmentation algorithm, the SOPHE interpolation scheme and the mosaic misorientation linewidth model greatly increase the speed of simulations for most spin systems. Employing brute force matrix diagonalization in the simulation of an EPR spectrum from a high spin Cr(III) complex with the spin Hamiltonian parameters g(e) = 2.00, D = 0.10 cm(-1), E/D = 0.25, A(x) = 120.0, A(y) = 120.0, A(z) = 240.0 x 10(-4) cm(-1) requires a SOPHE grid size of N = 400 (to produce a good signal to noise ratio) and takes 229.47 s. In contrast the use of either the SOPHE interpolation scheme or the mosaic misorientation linewidth model requires a SOPHE grid size of only N = 18 and takes 44.08 and 0.79 s, respectively. Results from Sophe are transferred via the Common Object Request Broker Architecture (CORBA) to XSophe and subsequently to XeprView((R)) where the simulated CW EPR spectra (1D and 2D) can be compared to the experimental spectra. Energy level diagrams, transition roadmaps and transition surfaces aid the interpretation of complicated randomly oriented CW EPR spectra and can be viewed with a web browser and an OpenInventor scene graph viewer.

Solution structure of robustoxin, the lethal neurotoxin from the funnel-web spider Atrax robustus

The solution structure of robustoxin, the lethal neurotoxin from the Sydney funnel-web spider Atrax robustus, has been determined from 2D H-1 NMR data, Robustoxin is a polypeptide of 42 residues cross-linked by four disulphide bonds, the connectivities of which were determined from NMR data and trial structure calculations to be 1-15, 8-20, 14-31 and 16-42 (a 1-4/2-6/3-7/5-8 pattern), The structure consists of a small three-stranded, anti-parallel beta-sheet and a series of interlocking gamma-turns at the C-terminus. It also contains a cystine knot, thus placing it in the inhibitor cystine knot motif family of structures, which includes the omega-conotoxins and a number of plant and animal toxins and protease inhibitors. Robustoxin contains three distinct charged patches on its surface, and an extended loop that includes several aromatic and non-polar residues, Both of these structural features may play a role in its binding to the voltage-gated sodium channel. (C) 1997 Federation of European Biochemical Societies.

The structure of a novel insecticidal neurotoxin, omega-atracotoxin-HV1, from the venom of an Australian funnel web spider

A family of potent insecticidal toxins has recently been isolated from the venom of Australian funnel web spiders. Among these is the 37-residue peptide omega-atracotoxin-HV1 (omega-ACTX-HV1) from Hadronyche versuta. We have chemically synthesized and folded omega-ACTX-HV1, shown that it is neurotoxic, ascertained its disulphide bonding pattern, and determined its three-dimensional solution structure using NMR spectroscopy. The structure consists of a solvent-accessible beta-hairpin protruding from a disulphide-bonded globular core comprising four beta-turns. The three intramolecular disulphide bonds form a cystine knot motif similar to that seen in several other neurotoxic peptides. Despite limited sequence identity, omega-ACTX-HV1 displays significant structural homology with the omega-agatoxins and omega-conotoxins, both of which are vertebrate calcium channel antagonists; however, in contrast with these toxins, we show that omega-ACTX-HV1 inhibits insect, but not mammalian, voltage-gated calcium channel currents.

The structure of versutoxin (delta-atracotoxin-Hv1) provides insights into the binding of site 3 neurotoxins to the voltage-gated sodium channel

Background: Versutoxin (delta-ACTX-Hv1) is the major component of the venom of the Australian Blue Mountains funnel web spider, Hadronyche versuta. delta-ACTX-Hv1 produces potentially fatal neurotoxic symptoms in primates by slowing the inactivation of voltage-gated sodium channels; delta-ACTX-Hv1 is therefore a useful tool for studying sodium channel function. We have determined the three-dimensional structure of delta ACTX-Hv1 as the first step towards understanding the molecular basis of its interaction with these channels. Results: The solution structure of delta-ACTX-Hv1, determined using NMR spectroscopy, comprises a core beta region containing a triple-stranded antiparallel beta sheet, a thumb-like extension protruding from the beta region and a C-terminal 3(10) helix that is appended to the beta domain by virtue of a disulphide bond. The beta region contains a cystine knot motif similar to that seen in other neurotoxic polypeptides. The structure shows homology with mu-agatoxin-l, a spider toxin that also modifies the inactivation kinetics of vertebrate voltage-gated sodium channels. More surprisingly, delta-ACTX-Hv1 shows both sequence and structural homology with gurmarin, a plant polypeptide. This similarity leads us to suggest that the sweet-taste suppression elicited by gurmarin may result from an interaction with one of the downstream ion channels involved in sweet-taste transduction. Conclusions: delta-ACTX-Hv1 shows no structural homology with either sea anemone or alpha-scorpion toxins, both of which also modify the inactivation kinetics of voltage-gated sodium channels by interacting with channel recognition site 3. However, we have shown that delta-ACTX-Hv1 contains charged residues that are topologically related to those implicated in the binding of sea anemone and alpha-scorpion toxins to mammalian voltage-gated sodium channels, suggesting similarities in their mode of interaction with these channels.

Synthesis and characterization of delta-atracotoxin-ar1a, the lethal neurotoxin from venom of the Sydney funnel-web spider (Atrax robustus)

delta-Atracotoxin-Ar1a (delta-ACTX-Ar1a) is the major polypeptide neurotoxin isolated from the venom of the male Sydney funnel-web spider, Atrax robustus. This neurotoxin targets both insect and mammalian voltage-gated sodium channels, where it competes with scorpion alpha-toxins for neurotoxin receptor site-3 to slow sodium-channel inactivation. Progress in characterizing the structure and mechanism of action of this toxin has been hampered by the limited supply of pure toxin from natural sources. In this paper, we describe the first successful chemical synthesis and oxidative refolding of the four-disulfide bond containing delta-ACTX-Ar1a. This synthesis involved solid-phase Boc chemistry using double coupling, followed by oxidative folding of purified peptide using a buffer of 2 M GdnHCl and glutathione/glutathiol in a 1:1 mixture of 2-propanol (pH 8.5). Successful oxidation and refolding was confirmed using both chemical and pharmacological characterization. Ion spray mass spectrometry was employed to confirm the molecular weight. H-1 NMR analysis showed identical chemical shifts for native and synthetic toxins, indicating that the synthetic toxin adopts the native fold. Pharmacological studies employing whole-cell patch clamp recordings from rat dorsal root ganglion neurons confirmed that synthetic delta-ACTX-Ar1a produced a slowing of the sodium current inactivation and hyperpolarizing shifts in the voltage-dependence of activation and inactivation similar to native toxin. Under current clamp conditions, we show for the first time that delta-ACTX-Ar1a produces spontaneous repetitive plateau potentials underlying the clinical symptoms seen during envenomation. This successful oxidative refolding of synthetic delta-ACTX-Ar1a paves the way for future structure-activity studies to determine the toxin pharmacophore.

Web-based screening and brief intervention for hazardous drinking: a double-blind randomized controlled trial

Background Strong evidence exists for the efficacy of screening and brief intervention for reducing hazardous drinking. However, problems have been highlighted with respect to its implementation in health-care systems, not least of which is a reluctance of some doctors to discuss alcohol proactively with their patients. Aims To determine the efficacy of a novel web-based screening and brief intervention (e-SBI) to reduce hazardous drinking. Design A double-blind randomized controlled trial. Setting A university student health service. Participants A total of 16 7 students (17-26 years) were recruited in the reception area and completed a 3-minute web-based screen including the Alcohol Use Disorder Identifiation Test (AUDIT) questionnaire. Of these, 112 tested positive, and 104 (52 females) who consented to follow-up were included in the trial. Measurements Drinking frequency, typical occasion quantity, total volume, heavy episode frequency (females > 80 g ethanol, males > 120 g ethanol), number of personal problems, an academic problems score. Intervention Participants were randomized to 10-15 minutes of web-based assessment and personalized feedback on their drinking (intervention, n = 5 1) or to a leaflet-only control group (n = 5 3). Findings Mean baseline AUDIT scores for control and intervention groups were 16.6 (SD = 6.0) and 16.6 (SD = 5.7). At 6 weeks, participants receiving e-SBI reported significantly lower total consumption (geometric mean ratio = 0.74; 9 5 % confidence interval: 0.56-0.96), lower heavy episode frequency (0.63; 0.42-0.92) and fewer personal problems (0.70; 0.54-0.91). At 6 months personal problems remained lower (0.76; 0.60-0.97), although consumption did not differ significantly. At 6 months, academic problems were lower in the intervention group relative to controls (0.72; 0.51-1.02). Conclusions e-SBI reduced hazardous drinking among university students, to an extent similar to that found for practitioner-delivered brief interventions in the general population. e-SBI offers promise as a strategy to reduce alcohol-related harm in a way that is non-intrusive, appealing to the target group, and capable of being incorporated into primary care. Research is required to replicate the findings, to determine the duration of intervention effects, and to investigate the mechanisms by which the intervention operates.

3-Homogeneous latin trades

Let T be a partial latin square and L be a latin square with T subset of L. We say that T is a latin trade if there exists a partial latin square T' with T' boolean AND T = theta such that (LT) U T' is a latin square. A k-homogeneous latin trade is one which intersects each row, each column and each entry either 0 or k times. In this paper, we construct 3-homogeneous latin trades from hexagonal packings of the plane with circles. We show that 3-homogeneous latin trades of size 3 m exist for each m >= 3. This paper discusses existence results for latin trades and provides a glueing construction which is subsequently used to construct all latin trades of finite order greater than three. Crown Copyright (c) 2005 Published by Elsevier B.V. All rights reserved.

Web services based state of the environment reporting

The Environmental Sciences Division within Queensland Environmental Protection Agency works to monitor, assess and model the condition of the environment. The Division has as a legislative responsibility to produce a whole-of-government report every four years dealing environmental conditions and trends in a ”State of the Environment report” (SoE)[1][2][3]. State of Environment Web Service Reporting System is a supplementary web service based SoE reporting tool, which aims to deliver accurate, timely and accessible information on the condition of the environment through web services via Internet [4][5]. This prototype provides a scientific assessment of environmental conditions for a set of environmental indicators. It contains text descriptions and tables, charts and maps with spatiotemporal dimensions to show the impact of certain environmental indicators on our environment. This prototype is a template based indicator system, to which the administrator may add new sql queries for new indicator services without changing the architecture and codes of this template. The benefits are brought through a service-oriented architecture which provides an online query service with seamless integration. In addition, since it uses web service architecture, each individual component within the application can be implemented by using different programming languages and in different operating systems. Although the services showed in this demo are built upon two datasets of regional ecosystem and protection area of Queensland, it will be possible to report on the condition of water, air, land, coastal zones, energy resources, biodiversity, human settlements and natural culture heritage on the fly as well. Figure 1 shows the architecture of the prototype. In the next section, I will discuss the research tasks in the prototype.