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The development of resistance to insecticides has become a classic exemplar of evolution occurring within human time scales. In this study we demonstrate how resistance to DDT in the major African malaria vector Anopheles gambiae is a result of both target-site resistance mechanisms that have introgressed between incipient species (the M- and S-molecular forms) and allelic variants in a DDT-detoxifying enzyme. Sequencing of the detoxification enzyme, Gste2, from DDT resistant and susceptible strains of An. gambiae, revealed a non-synonymous polymorphism (I114T), proximal to the DDT binding domain, which segregated with strain phenotype. Recombinant protein expression and DDT metabolism analysis revealed that the proteins from the susceptible strain lost activity at higher DDT concentrations, characteristic of substrate inhibition. The effect of I114T on GSTE2 protein structure was explored through X-ray crystallography. The amino acid exchange in the DDT-resistant strain introduced a hydroxyl group nearby the hydrophobic DDT-binding region. The exchange does not result in structural alterations but is predicted to facilitate local dynamics and enzyme activity. Expression of both wild-type and 114T alleles the allele in Drosophila conferred an increase in DDT tolerance. The 114T mutation was significantly associated with DDT resistance in wild caught M-form populations and acts in concert with target-site mutations in the voltage gated sodium channel (Vgsc-1575Y and Vgsc-1014F) to confer extreme levels of DDT resistance in wild caught An. gambiae. [ABSTRACT FROM AUTHOR]

Malaria control relies heavily on pyrethroid insecticides, to which susceptibility is declining in Anopheles mosquitoes. To combat pyrethroid resistance, application of alternative insecticides is advocated for indoor residual spraying (IRS), and carbamates are increasingly important. Emergence of a very strong carbamate resistance phenotype in Anopheles gambiae from Tiassalé, Côte d'Ivoire, West Africa, is therefore a potentially major operational challenge, particularly because these malaria vectors now exhibit resistance to multiple insecticide classes. We investigated the genetic basis of resistance to the most commonly-applied carbamate, bendiocarb, in An. gambiae from Tiassalé. Geographically-replicated whole genome microarray experiments identified elevated P450 enzyme expression as associated with bendiocarb resistance, most notably genes from the CYP6 subfamily. P450s were further implicated in resistance phenotypes by induction of significantly elevated mortality to bendiocarb by the synergist piperonyl butoxide (PBO), which also enhanced the action of pyrethroids and an organophosphate. CYP6P3 and especially CYP6M2 produced bendiocarb resistance via transgenic expression in Drosophila in addition to pyrethroid resistance for both genes, and DDT resistance for CYP6M2 expression. CYP6M2 can thus cause resistance to three distinct classes of insecticide although the biochemical mechanism for carbamates is unclear because, in contrast to CYP6P3, recombinant CYP6M2 did not metabolise bendiocarb in vitro. Strongly bendiocarb resistant mosquitoes also displayed elevated expression of the acetylcholinesterase ACE-1 gene, arising at least in part from gene duplication, which confers a survival advantage to carriers of additional copies of resistant ACE-1 G119S alleles. Our results are alarming for vector-based malaria control. Extreme carbamate resistance in Tiassalé An. gambiae results from coupling of over-expressed target site allelic variants with heightened CYP6 P450 expression, which also provides resistance across contrasting insecticides. Mosquito populations displaying such a diverse basis of extreme and cross-resistance are likely to be unresponsive to standard insecticide resistance management practices. [ABSTRACT FROM AUTHOR]

The resistance of mosquitoes to chemical insecticides is threatening vector control programmes worldwide. Cytochrome P450 monooxygenases (CYPs) are known to play a major role in insecticide resistance, allowing resistant insects to metabolize insecticides at a higher rate. Among them, members of the mosquito CYP6Z subfamily, like Aedes aegypti CYP6Z8 and its Anopheles gambiae orthologue CYP6Z2, have been frequently associated with pyrethroid resistance. However, their role in the pyrethroid degradation pathway remains unclear. In the present study, we created a genetically modified yeast strain overexpressing Ae. aegypti cytochrome P450 reductase and CYP6Z8, thereby producing the first mosquito P450- CPR (NADPH-cytochrome P450-reductase) complex in a yeast recombinant system. The results of the present study show that: (i) CYP6Z8 metabolizes PBAlc (3-phenoxybenzoic alcohol) and PBAld (3-phenoxybenzaldehyde), common pyrethroid metabolites produced by carboxylesterases, producing PBA (3- phenoxybenzoic acid); (ii) CYP6Z8 transcription is induced by PBAlc, PBAld and PBA; (iii) An. gambiae CYP6Z2 metabolizes PBAlc and PBAld in the sameway; (iv) PBAis the majormetabolite produced in vivo and is excreted without further modification; and (v) in silico modelling of substrate-enzyme interactions supports a similar role of other mosquito CYP6Zs in pyrethroid degradation. By playing a pivotal role in the degradation of pyrethroid insecticides, mosquito CYP6Zs thus represent good targets for mosquito-resistance management strategies. [ABSTRACT FROM AUTHOR]

The fight against diseases spread by mosquitoes and other insects has enormous environmental, economic and social consequences. Chemical insecticides remain the first line of defence but the control of diseases, especially malaria and dengue fever, is being increasingly undermined by insecticide resistance. Mosquitoes have a large repertoire of P450s (over 100 genes). By pinpointing the key enzymes associated with insecticide resistance we can begin to develop new tools to aid the implementation of control interventions and reduce their environmental impact on Earth. Recent technological advances are helping us to build a functional profile of the P450 determinants of insecticide metabolic resistance in mosquitoes. Alongside, the cross-responses of mosquito P450s to insecticides and pollutants are also being investigated. Such research will provide the means to produce diagnostic tools for early detection of P450s linked to resistance. It will also enable the design of new insecticides with optimized efficacy in different environments. [ABSTRACT FROM AUTHOR]

Pyrethroid insecticides are critical for malaria control in Africa. However, resistance to this insecticide class in the malaria vector Anopheles funestus is spreading rapidly across Africa, threatening the success of ongoing and future malaria control programs. The underlying resistance mechanisms driving the spread of this resistance in wild populations remain largely unknown. Here, we show that increased expression of two tandemly duplicated P450 genes, CYP6P9a and CYP6P9b, is the main mechanism driving pyrethroid resistance in Malawi and Mozambique, two southern African countries where this insecticide class forms the mainstay of malaria control. Genome-wide transcription analysis using microarray and quantitative RT-PCR consistently revealed that CYP6P9a and CYP6P9b are the two genes most highly overexpressed (>50-fold; q < 0.01) in permethrin-resistant mosquitoes. Transgenic expression of CYP6P9a and CYP6P9b in Drosophila melanogaster demonstrated that elevated expression of either of these genes confers resistance to both type I (permethrin) and type II (deltamethrin) pyrethroids. Functional characterization of recombinant CYP6P9b confirmed that this protein metabolized both type I (permethrin and bifenthrin) and type II (deltamethrin and Lambda-cyhalothrin) pyrethroids but not DDT. Variability analysis identified that a single allele of each of these genes is predominantly associated with pyrethroid resistance in field populations from both countries, which is suggestive of a single origin of this resistance that has since spread across the region. Urgent resistance management strategies should be implemented in this region to limit a further spread of this resistance and minimize its impact on the success of ongoing malaria control programs. [ABSTRACT FROM AUTHOR]

Magnetisation transfer ratio (MTR) can reveal the degree of proton exchange between free water and macromolecules and was suggested to be pathological informative. We aimed to investigate changes in optic nerve MTR over 12 months following acute optic neuritis (ON) and to determine whether MTR measurements can predict clinical and paraclinical outcomes at 6 and 12 months. Thirty-seven patients with acute ON were studied within 2 weeks of presentation and at 1, 3, 6 and 12 months. Assessments included optic nerve MTR, retinal nerve fibre layer (RNFL) thickness, multifocal visual evoked potential (mfVEP) amplitude and latency and high (100%) and low (2.5%) contrast letter acuity. Eleven healthy controls were scanned twice four weeks apart for comparison with patients. Patient unaffected optic nerve MTR did not significantly differ from controls at any time-point. Compared to the unaffected nerve, affected optic nerve MTR was significantly reduced at 3 months (mean percentage interocular difference =29.24%, p = 0.01), 6 months (mean =212.48%, p,0.0001) and 12 months (mean =27.61%, p = 0.003). Greater reduction in MTR at 3 months in patients was associated with subsequent loss of high contrast letter acuity at 6 (r = 0.60, p = 0.0003) and 12 (r = 0.44, p = 0.009) months, low contrast letter acuity at 6 (r = 0.35, p = 0.047) months, and RNFL thinning at 12 (r = 0.35, p = 0.044) months. Stratification of individual patient MTR time courses based on flux over 12 months (stable, putative remyelination and putative degeneration) predicted RNFL thinning at 12 months (F2,32 = 3.59, p = 0.02). In conclusion, these findings indicate that MTR flux after acute ON is predictive of axonal degeneration and visual disability outcomes. [ABSTRACT FROM AUTHOR]

Trans-synaptic degeneration could exacerbate neurodegeneration in multiple sclerosis (MS). We aimed to assess whether anterograde trans-synaptic degeneration could be identified in the primary visual pathway in vivo. Diffusion tensor imaging (DTI) was used to assess the optic radiations in 15 patients with previous optic nerve inflammation and 9 healthy volunteers. A probabilistic atlas of the optic radiations was created from healthy diffusion tractography data. Lengthwise profiles for DTI parameters (axial [λ||], radial [λ⟂] and mean diffusivity [MD], fractional anisotropy [FA] and the angle of deviation of the principal eigenvector [α]) were analyzed for patients and controls. Patients also underwent multifocal visual evoked potential (mfVEP) assessments to characterize the latency and amplitude of cortical potentials. Correlations were performed between mfVEP latency and amplitude in the left and right visual hemi-fields and DTI parameters in the contra-lateral optic radiations. Patients displayed a significant decrease in λ|| within the body of both optic radiations, which significantly correlated with loss of mfVEP amplitude. Abnormal λ⟂ and FA were detected bilaterally throughout the optic radiations in patients but the abnormality was not associated with amplitude reduction or latency prolongation of the mfVEP. An abnormal α value was observed in the left optic radiations of patients, and the α value in the body of the optic radiations also correlated with mfVEP amplitude loss. The assocation between bilateral DTI abnormalities within the optic radiations and loss of afferent electrical activity could indicate anterograde trans-synaptic degeneration occurs following optic neuritis. Hum Brain Mapp 33:2047-2061, 2012. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

In the last decade there have been marked reductions in malaria incidence in sub-Saharan Africa. Sustaining these reductions will rely upon insecticides to control the mosquito malaria vectors. We report that in the primary African malaria vector, Anopheles gambiae sensu stricto, a single enzyme, CYP6M2, confers resistance to two classes of insecticide. This is unique evidence in a disease vector of cross-resistance associated with a single metabolic gene that simultaneously reduces the efficacy of two of the four classes of insecticide routinely used for malaria control. The gene-expression profile of a highly DDT-resistant population of A. gambiae s.s. from Ghana was characterized using a unique whole-genome microarray. A number of genes were significantly overexpressed compared with two susceptible West African colonies, including genes from metabolic families previously linked to insecticide resistance. One of the most significantly overexpressed probe groups (false-discovery rate-adjusted P < 0.0001) belonged to the cytochrome P450 gene CYP6M2. This gene is associated with pyrethroid resistance in wild A. gambiae s.s. populations) and can metabolize both type I and type II pyrethroids in recombinant protein assays. Using in vitro assays we show that recombinant CYP6M2 is also capable of metabolizing the organochlorine insecticide DDT in the presence of solubilizing factor sodium cholate. [ABSTRACT FROM AUTHOR]

NADPH-cytochrome P450 oxidoreductase (CPR) plays a central role in chemical detoxification and insecticide resistance in Anopheles gambiae, the major vector for malaria. Anopheles gambiae CPR (AgCPR) was initially expressed in Eschericia coli but failed to bind 29, 59-ADP Sepharose. To investigate this unusual trait, we expressed and purified a truncated histidinetagged version for side-by-side comparisons with human CPR. Close functional similarities were found with respect to the steady state kinetics of cytochrome c reduction, with rates (kcat) of 105 s-1 and 88 s-1, respectively, for mosquito and human CPR. However, the inhibitory effects of 29,59-ADP on activity were different; the IC50 value of AgCPR for 29, 59 -ADP was significantly higher (6-10 fold) than human CPR (hCPR) in both phosphate and phosphate-free buffer, indicative of a decrease in affinity for 29, 59- ADP. This was confirmed by isothermal titration calorimetry where binding of 29,59-ADP to AgCPR (Kd = 410618 nM) was ,10 fold weaker than human CPR (Kd = 38 nM). Characterisation of the individual AgFMN binding domain revealed much weaker binding of FMN (Kd=8362.0 nM) than the equivalent human domain (Kd=2360.9 nM). Furthermore, AgCPR was an order of magnitude more sensitive than hCPR to the reductase inhibitor diphenyliodonium chloride (IC50=28 mM62 and 361631 μM respectively). Taken together, these results reveal unusual biochemical differences between mosquito CPR and the human form in the binding of small molecules that may aid the development of 'smart' insecticides and synergists that selectively target mosquito CPR. [ABSTRACT FROM AUTHOR]

Over-expression of the cytochrome P450 CYP6CM1 gene has been associated with imidacloprid resistance in a number of Q and B biotype Bemisia tabaci laboratory strains from distinct geographical origins worldwide. We recently demonstrated that the Q biotype version of the CYP6CM1 protein ( CYP6CM1vQ) is capable of metabolizing imidacloprid. Here, we show that the levels of BtCYP6CM1vQ were also elevated in laboratory-resistant strains and field-derived populations, with variable imidacloprid resistance levels, collected in Crete. High levels of CYP6CM1vQ transcripts were also determined in survivors of a heterogeneous field population, after exposure to discriminating imidacloprid dosage. Using peptide antibody-based detection assays, we demonstrated that in line with transcriptional data, the CYP6CM1vQ protein levels were higher in imidacloprid-resistant insects, which further implicates the gene as the causal factor of resistance. Finally, assessment of the cross-metabolism potential of CYP6CM1vQ against additional neonicotinoid molecules used for B. tabaci control revealed that clothianidin and thiacloprid, but not acetamiprid or thiamethoxam, are metabolized by the recombinant enzyme in vitro. [ABSTRACT FROM AUTHOR]

Electrohydrodynamic jet printing (EHJP) technology was demonstrated by fabricating metallic patterns, using a commercialized silver metallo-organic ink. The electrospray was operated in a full voltage-controlled form but without the auxiliary assistance of gas pressure. The freeform deposition of basic structures of patterns was demonstrated, for the first time, by using the unforced electrospray. After heat treatment at 250 °C, an energy-dispersive X-ray spectrum confirmed that the main composition was silver in the patterns. Scanning electron microscope analysis revealed that dense packed silver crystallites were present in the fabricated patterns. An electrical resistivity of 4.34 × 10−8 Ωm, close to the theoretical resistivity of bulk silver, was obtained in the 100 μm-width printed tracks. [ABSTRACT FROM AUTHOR]

Water issues are a feature of public debate in Australia. The increasing privatisation of water and changes to water allocation systems are resulting in change, often referred to as water 'wars' (de Villiers, 1999). The Australian dairy industry uses 25% of the surface irrigation water in Australia. How does a rural industry like dairying negotiate a future? What is the role of broker professions like extension in supporting change in this context? We focus on three critical issues to address these questions: farm-level adaptation; new technologies; and balancing environmental and productive water-use. Two case studies of farm decision-making and advisory practice suggest that managing complexity in water issues requires learning processes at three levels: farmer-advisor; advisors-policy; advisors-other disciplines-policy. We conclude there is a need for a framework to guide an ethical response to water policy, bringing farm adaptation and advisory practice to implement change. [ABSTRACT FROM AUTHOR]

Electrosprays routinely create sub-micron droplets containing functional molecules and show promise as a drop-on-demand dispensing method in the life sciences and materials processing. To precisely eject minute liquid volumes electrosprays must be turned on for milliseconds or less in the cone-jet or high-frequency pulsation mode. This work reports sequential phenomena which occur when electrosprays are triggered by sudden voltage steps. For low voltages the electrospray enters the pulsation mode but the pulsation frequency increases towards an asymptote, which increases with voltage. For higher voltages the asymptotic frequency is above a critical value and the electrospray switches to the cone-jet mode; after this the ejection rate increases until finally reaching a steady state. The total delay involves these phenomena plus the delay in forming a liquid cone; the latter depends strongly on both the initial and final voltage. The final electric field that must be applied is smaller when the electric field the liquid is subjected to initially is small—it is proposed that the inertia of a dynamically forming cone plays a role in lowering the voltage needed. [ABSTRACT FROM AUTHOR]

This study presents the neuro-otological findings of 523 patients attending a tertiary vestibular clinic with migraine- and nonmigraine-related dizziness. Subjects were categorized into one of 4 groups, definite migrainous vertigo, probable migrainous vertigo, vestibular disorder coexisting with migraine and nonmigraine-related dizziness. No notable relationship was found between the numbers of abnormal findings between the groups for the majority of the neuro-otological tests. However, there was a significant trend in emetic response to caloric testing. The definite migrainous vertigo group were at least 4 times more likely to be nauseous to caloric testing than any other migraine category. This difference was independent of the magnitude of caloric responses between the emetic migraine groups. While further investigation is required, this study has potentially identified that nauseous/emetic response to caloric stimulation may be a distinguishing factor between migrainous vertigo and other vestibular disorders including those with a coexisting history of migraine. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

In recent decades we have witnessed a diversification of rural communities, where the agricultural sector has had to increasingly compete with other interests and demands on rural land. Land management agencies have recognised that in order to resolve sustainability dilemmas, it is important to bring the diverse stakeholders together to negotiate the sustainable use of land and natural resources. Such collaborative approaches can only be effective if there is some sense of integration between various stakeholders. This paper explores how integration among diverse stakeholders can be facilitated in a way that accommodates and embraces diversity. It does this through an investigation of a project implemented by the Victorian state government that aimed to involve a diversity of stakeholders in the land management process. [ABSTRACT FROM AUTHOR]

Post-modern theorists have challenged the totalizing and unifying ambitions of change management practices. This paper explores how a narrative action research approach may be used to combine our modernist commitment to facilitate change and collaboration in the land management context with a post-modern sensitivity to complexity and difference. It critically examines the way in which this approach was implemented within a Victorian state government project that attempted to instigate a collaborative approach to land management. The narrative action research approach problematized the project team's representations of the project and brought into view the way in which these erased the space for genuine participation by the broader community. However, while the narrative action research approach highlighted some of the ambiguities that existed within the project, it did very little to change the course of the project. The paper identifies ways in which the approach needs to be modified and concludes that it warrants further research and development. [ABSTRACT FROM AUTHOR]

Managing the competing interests of productivity growth, environmental concerns, landscape change and societal expectations presents challenges for agricultural industries. Innovation projects supporting knowledge development to address these challenges often involve partnerships with commercial farms, a methodology which promises much but has inherent challenges as well. This paper will examine the requirements of learning partnerships between farmers, research and extension (as members of innovation projects) to address conditions of complexity. We review designs for the involvement of commercial farms in innovation projects and explore the conditions for effective learning partnerships using two case studies from the Australian dairy industry. Learning partnerships with commercial farms can contribute to addressing the conditions of complexity faced by agricultural industries. Our analysis suggests that the conditions for effective learning partnerships involve the active negotiation of learning roles between farmers, researchers and advisors. This requires a unique form of facilitation to support the learning environment and use of learning tools, assisting project teams to act on complex issues. As learning partners, commercial farms in innovation projects are an effective response to the challenges of complexity in agricultural innovation. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to examine the role of reductive activation of mitoxantrone (MX) by human liver NADPH cytochrome P450 reductase (CPR) in increasing its ability to inhibit the growth of human promyelocytic sensitive leukaemia HL60 cell line as well as its MDR sublines exhibiting two different phenotypes of MDR related to the overexpression of P-glycoprotein (HL60/VINC) or MRP1 (HL60/DOX). Our assays showed that the reduction of MX by exogenously added CPR in the presence of low NADPH concentration had no effect in increasing its ability to inhibit the growth of sensitive and MDR tumour cells. In contrast, an important increase in antiproliferative activity of MX after its reductive activation by CPR at high NADPH concentration was observed against HL60/VINC as well as HL60/DOX cells. [Copyright &y& Elsevier]

Abstract: Unforced nanoelectrospray can exhibit a number of stable spray modes. These include low frequency pulsations, high frequency pulsations, and a steady cone-jet. Experiments are reported here on such pulsations that have been observed in various salt loaded solutions of ethylene glycol, triethylene glycol and water. The spray current was monitored with 1 μs time resolution to show that spray regime characteristics depend on nozzle diameter and liquid conductivity. The frequency of pulsations was found to increase with both increased liquid conductivity and decreasing nozzle diameter. The charge ejected during a pulse is lower for smaller nozzles spraying higher conductivity liquids. Water solutions were observed undergoing high frequency pulsations, with these pulsations often occurring in lower frequency bursts. The frequencies of water pulsations were as high as 635 kHz but the charge ejected by each pulsation was an order of magnitude lower than that observed in triethylene glycol. An unforced electrospray of water was also identified as being in the steady cone-jet mode with a higher degree of confidence than previously. The values for stable pulsation frequency and charge ejected observed in ethylene glycol lay between those of TEG and water. [Copyright &y& Elsevier]

New modes of nanoelectrospray (nES) have been identified that exhibit stable high-frequency current oscillations in the kilohertz range. In-line flow rate measurements during nES have for the first time allowed the accurate determination of the spray current and volumetric flow rate dependence on applied voltage. High-speed video imaging has revealed that each current pulse corresponds to the periodic formation of a short-lived stable cone-jet structure at the capillary tip. These findings are of particular importance and suggest greater process monitoring and control in nES-MS systems is necessary if efficiency and ion yield are to be optimized. [ABSTRACT FROM AUTHOR]

Previous research has suggested that free-ranging mourning doves (Zenaida macroura) may ingest spent lead pellets, succumb to lead toxicosis, and die in a relatively short time (i.e., an acute lead toxicosis hypothesis). We tested this hypothesis by administering 157 captive mourning doves 2-24 lead pellets, monitoring pellet retention and short-term survival, and measuring related physiological characteristics. During the 19- to 21-day posttreatment period, 104 doves that received lead pellets died (deceased doves) and 53 survived (survivors); all 22 birds in a control group survived. Within 24-hr of treatment, blood lead levels increased almost twice as fast for deceased doves compared to survivors (F1,208 = 55.49; P < 0.001). During the first week, heterophihlymphocyte (H:L) ratios increased twice as fast for deceased doves than with survivors (F1,198 = 23.14, P < 0.001). Posttreatment survival differed (χ² = 37.4, P < 0.001) among the 5 groups of doves that retained different numbers of pellets, and survival ranged from 0.57 (95% CI: 0.44-0. 74) for doves that retained ≤2 lead pellets 2 days posttreatment compared to 0.08 (95% Ch 0.022-0.31) for those doves that retained 13-19 lead pellets on 2 days posttreatment; significant differences existed among the 5 groups. After controlling for dove pretreatment body mass, each additional lead pellet increased the hazard of death by 18.0% (95% CI: 1.132-1.230, P < 0.001) and 25. 7% (95% Ch 1.175-1.345, P < 0.001) for males and females, respectively. For each 1-g increase in pretreatment body mass, the hazard of death decreased 2.5% (P = 0.04) for males and 3.8% (P = 0.02) for females. Deceased doves had the highest lead levels in liver (49.20 ± 3.23 ppm) and kidney (258.16 ± 21.85 ppm) tissues, whereas controls showed the lowest levels (liver, 0.08 ± 0.041 ppm; kidney, 0.17 ± 0.10 ppm). For doves dosed with pellets, we observed simultaneous increases in blood lead levels and H:L ratios, whereas packed-cell volume (PCV) values declined. Our results support an acute lead toxicosis hypothesis. Although further research is necessary to investigate the magnitude of lead shot ingestion and toxicosis in mourning doves, we recommend that management agencies initiate development of a long-term strategic plan aimed at implementing a nontoxic shot regulation for mourning dove hunting. [ABSTRACT FROM AUTHOR]

The public policy process in Australia is changing towards a more interactive, collaborative model, where governments seek to develop partnerships with civil society and private sector organisations to manage complex policy challenges. This article discusses research conducted into a project implemented by a Victorian government department that sought to involve stakeholders in addressing natural resource management issues in the agricultural sector. The research revealed that public administration practices associated with the new public management approach impeded the ability of the project to facilitate participation by diverse stakeholders in the decision-making process. The article challenges the view that the discourse of collaboration and community engagement takes public administration down a constructivist path and suggests that agencies need to become reflexive about the way in which public administration practices are constitutive of the community engagement process if they are to facilitate genuine participation of other stakeholders. [ABSTRACT FROM AUTHOR]

The thermodynamics of coenzyme binding to human cytochrome P450 reductase (CPR) and its isolated FAD-binding domain have been studied by isothermal titration calorimetry. Binding of 2',5'- ADP, NADP+, and H4NADP, an isosteric NADPH analogue, is described in terms of the dissociation binding constant (Kd), the enthalpy (ΔHB) and entropy (TΔSB) of binding, and the heat capacity change (ΔCp). This systematic approach allowed the effect of coenzyme redox state on binding to CPR to be determined. The recognition and stability of the coenzyme-CPR complex are largely determined by interaction with the adenosine moiety (Kd2',5-ADP = 76 nM), regardless of the redox state of the nicotinamide moiety. Similar heat capacity change (ΔCp) values for 2',5'-ADP (-210 cal mol-1 K-1), NADP+ (-230 cal mol-1 K-1), and H4NADP (-220 cal mol-1 K-1) indicate no significant contribution from the nicotinamide moiety to the binding interaction surface. The coenzyme binding stoichiometry to CPR is 1:1. This result validates a recently proposed one-site kinetic model [Daff, S. (2004) Biochemistry 43, 3929-3932] as opposed to a two-site model previously suggested by us [Gutierrez, A., Lian, L.-Y., Wolf, C. R., Scrutton, N. S., and Roberts, C. G. K. (2001) Biochemistry 40, 1964-1975]. Calorimetric studies in which binding of 2',5'-ADP to CPR (TΔSB = -13400 ± 200 cal mol-1, 35 °C) was compared with binding of the same ligand to the isolated FAD-binding domain (TΔSB -11200 ± 300 cal mol-1, 35 °C) indicate that the number of accessible conformational substates of the protein increases upon 2',5'-ADP binding in the presence of the FMN-binding domain. This pattern was consistently observed along the temperature range that was studied (5-35 °C). This contribution of coenzyme binding energy to domain dynamics in CPR agrees with conclusions from previous temperature-jump studies [Gutierrez, A., Paine, M., Wolf, C. R., Scrutton, N. S., and Roberts, G. C. K. (2002) Biochemistry 4], 4626-4637]. A combination of calorimetry and stopped-flow spectrophotometry kinetics experiments showed that this linkage between coenzyme binding energetics and diffusional domain motion impinges directly on the molecular recognition of cytochrome c by CPR. Single-turnover reduction of cytochrome c by CPR (kmax = 15 s-1, Kd = 37 μM) is critically coupled to coenzyme binding through ligand-induced motions that enable the FMN-binding domain to overcome a kinetically unproductive conformation. This is remarkable since the FMN-binding domain is not directly involved in coenzyme binding, the NADP(H) binding site being fully contained in the FAD-binding domain. Sequential rapid mixing measurements indicate that harnessing of coenzyme binding energy to the formation of a kinetically productive CPR-cytochrome c complex is a highly synchronized event. The inferred half-time for the decay of this productive conformation (τ) is 330 ± 70 ms only. Previously proposed structural and kinetic models are discussed in light of these findings. [ABSTRACT FROM AUTHOR]

Abstract: Drilling and pit wall exposures at the southern end of the Bondi Main heavy mineral beach placer deposit provided access to the Loxton–Parilla sands, which are here divided into five lithofacies. The depositional environment of each lithofacies is interpreted as shoaling zone, breaker zone, surf zone, swash zone, and backshore dune. Other units encountered include the Duddo Limestone, Loddon River Group, Bookpurnong Formation, and Shepparton Formation. The interpreted depositional environments for these units are, respectively, shallow marine, fluvial, shallow marine/shelf, and fluvio-lacustrine. A palaeogeographical model is presented, which proposes that the Bondi Main deposit formed at the southern end of a north-trending shoreline. This shoreline was truncated to the south by the Dundas Tableland and is broadly analogous in its geomorphological setting to the modern Geographe Bay in Western Australia. The deposit therefore appears to have formed in association with a heavy mineral “trap” at its southern end. Postdepositional weathering overprints include ferruginous mottling, clay eluviation, and possibly quartz fracturing and disaggregation. The ferruginous mottles formed under spatially and temporally variable redoximorphic conditions, with Fe being derived from the weathering of Fe-bearing primary minerals, particularly ilmenite. Postdepositional clays in the Loxton–Parilla sands are interpreted as being derived from the overlying Shepparton Formation. [Copyright &y& Elsevier]

Human novel reductase 1 (NR1) is an NADPH dependent diflavin oxidoreductase related to cytochrome P450 reductase (CPR). The FAD/NADPH- and FMN-binding domains of NR1 have been expressed and purified and their redox properties studied by stopped-flow and steady-state kinetic methods, and by potentiometry. The midpoint reduction potentials of the oxidized/semiquinone (-315 ± 5 mV) and semiquinone/dihydroquinone (-365 ± 15 mV) couples of the FAD/NADPH domain are similar to those for the FAD/NADPH domain of human CPR, but the rate of hydride transfer from NADPH to the FAD/NADPH domain of NR1 is ≈ 200-fold slower. Hydride transfer is rate-limiting in steady-state reactions of the FAD/NADPH domain with artificial redox acceptors. Stopped-flow studies indicate that hydride transfer from the FAD/NADPH domain of NR1 to NADP+ is faster than hydride transfer in the physiological direction (NADPH to FAD), consistent with the measured reduction potentials of the FAD couples [midpoint potential for FAD redox couples is -340 mV, cf -320 mV for NAD(P)H]. The midpoint reduction potentials for the flavin couples in the FMN domain are -146 ± 5 mV (oxidized/semiquinone) and -305 ± 5 mV (semiquinone/dihydroquinone). The FMN oxidized/semiquinone couple indicates stabilization of the FMN semiquinone, consistent with (a) a need to transfer electrons from the FAD/NADPH domain to the FMN domain, and (b) the thermodynamic properties of the FMN domain in CPR and nitric oxide synthase. Despite overall structural resemblance of NR1 and CPR, our studies reveal thermodynamic similarities but major kinetic differences in the electron transfer reactions catalysed by the flavin-binding domains. [ABSTRACT FROM AUTHOR]

Abstract Ophthalmic artery hypoperfusion is a relatively uncommon clinical entity. This study illustrates the posterior segment findings of ophthalmic artery hypoperfusion in a series of nine patients. Colour photographs and relevant fluorescein angiograms highlighting the findings are shown. The retinal manifestations of ophthalmic artery hypoperfusion in this series of patients include midperipheral haemorrhages, dilated retinal veins, optic disk collaterals, optic disk neo­vascularization, cotton wool spots, grey intraretinal lesions, fundus pallor, optic disk swelling and choroidal infarcts. Recognition of the ophthalmic changes in this condition may lead to detection of carotid artery disease, the surgical and medical treatment of which has important bearing on patient management. [ABSTRACT FROM AUTHOR]

Studies the kinetics of internal electron transfer in human cytochrome P450 reductase (CPR). Reduction of temperature perturbation of CPR; Equilibrium states in chemical relaxation reactions with two-electron-reduced CPR; Data of the absorption spectra of two-electron-reduced CPR.

Purpose: To highlight that internal carotid artery dissection is a common cause of Horner's syndrome and that it is important to diagnose dissection as anticoagulation can prevent carotid thrombosis and embolism. Methods: Five case reports are presented of patients with Horner's syndrome secondary to carotid dissection. One patient had carotid dissection secondary to trauma, two had spontaneous dissections and two had dissections in the settings of other illness. A literature search was performed on carotid dissection as a cause of Horner's syndrome and its diagnosis and management. Results: The case reports and literature highlight that dissection is under-recognized as a cause of Horner's syndrome and can be missed. The investigation of choice is a magnetic resonance imaging and angiography scan of the head and neck.The treatment advocated is anticoagulation for 3-6 months. Conclusion: Carotid dissection should be suspected in patients with Horner's syndrome, particularly if head or neck pain is present. [ABSTRACT FROM AUTHOR]

Examines the role of the conserved phenylalanine 181 of NADHP-cytochrome P450 oxidoreductase in FMN binding and catalytic activity. Involvement of Tyrl140 and Tyrl178 in FMN binding; Reduction and oxidation potentials and binding energies of the FMN complexes; Comparison of the binding energies of the wild-type and mutant enzymes.

Presents a paper which adopts a knowledge systems framework incorporating networking dimensions to explore problems of supply-chain reorganization. How this framework is being applied in New Zealand agri-industries.