Enzyme-catalysed synthesis and reactions of benzene oxide/oxepine derivatives of methyl benzoates

A series of twelve benzoate esters was metabolised, by species of the Phellinus genus of wood-rotting fungi, to yield the corresponding benzyl alcohol derivatives and eight salicylates. The isolation of a stable oxepine metabolite, from methyl benzoate, allied to evidence of the migration and retention of a carbomethoxy group ( the NIH Shift), during enzyme-catalysed ortho-hydroxylation of alkyl benzoates to form salicylates, is consistent with a mechanism involving an initial arene epoxidation step. This mechanism was confirmed by the isolation of a remarkably stable, optically active, substituted benzene oxide metabolite of methyl 2-( trifluoromethyl) benzoate, which slowly converted into the racemic form. The arene oxide was found to undergo a cycloaddition reaction with 4-phenyl-1,2,4-triazoline-3,5-dione to yield a crystalline cycloadduct whose structure and racemic nature was established by X-ray crystallography. The metabolite was also found to undergo some novel benzene oxide reactions, including epoxidation to give an anti-diepoxide, base-catalysed hydrolysis to form a trans-dihydrodiol and acid-catalysed aromatisation to yield a salicylate derivative via the NIH Shift of a carbomethoxy group.

Activity against Mycobacterium smegmatis and M. tuberculosis by extract of South African medicinal plants

Seven ethnobotanically selected medicinal plants were screened for their antimycobacterial activity. The mininium inhibitory concentration (MIC) of four plants namely Artemisia afra, Dodonea angustifolia, Drosera capensis and Galenia africana ranged from 0.781 to 6.25 mg/mL against Mycobacterium smegmatis. G. africana showed the best activity exhibiting an MIC of 0.78 mg/mL and a minimum bactericidal concentration (MBC) of 1.56 mg/mL. The MICs of ethanol extracts of A angustifolia and G. africana against M. tuberculosis were found to be 5.0 and 1.2 mg/mL respectively. The mammalian cytotoxicity IC50 value of the most active antimycobacterial extract, from G. africana, was found to be 101.3 mu g/mL against monkey kidney Vero cells. Since the ethanol G. africana displayed the best antimycobacterial activity, it was subjected to fractionation which led to the isolation of a flavone, 5,7,2'-trihydroxyflavone. The MIC of this compound was found to be 0.031 mg/mL against M. smegmatis and 0.10 mg/mL against M. tuberculosis. This study gives some scientific basis to the 14 traditional use of these plants for TB-related symptoms. Copyright (C) 2008 John Wiley & Sons, Ltd.

A tip-high, Ca2+-interdependent, reactive oxygen species gradient is associated with polarized growth in Fucus serratus zygotes

We report the existence of a tip-high reactive oxygen species (ROS) gradient in growing Fucus serratus zygotes, using both 5-(and 6-) chloromethyl-2',7'-dichlorodihydrofluorescein and nitroblue tetrazolium staining to report ROS generation. Suppression of the ROS gradient inhibits polarized zygotic growth; conversely, exogenous ROS generation can redirect zygotic polarization following inhibition of endogenous ROS. Confocal imaging of fluo-4 dextran distributions suggests that the ROS gradient is interdependent on the tip-high [Ca2+](cyt) gradient which is known to be associated with polarized growth. Our data support a model in which localized production of ROS at the rhizoid tip stimulates formation of a localized tip-high [Ca2+](cyt) gradient. Such modulation of intracellular [Ca2+](cyt) signals by ROS is a common motif in many plant and algal systems and this study extends this mechanism to embryogenesis.

Upper and lower bounds of 180 degrees unit element of a ridge waveguide: Calculations and measurements

The upper and lower bounds on the actual solution of any microwave structure is of general interest. The purpose of this letter is to compare some calculations using the mode-matching and finite-element methods, with some measurements on a 180 degrees ridge waveguide insert between standard WR62 rectangular waveguides. The work suggests that the MMM produces an upper bound, while the FEM places a lower bound on the measurement. (C) 2001 John Wiley & Sons, Inc.

Raman spectroscopy of advanced glycation end products (AGEs), possible markers for progressive retinal dysfunction

Raman microscopy is used to investigate the spectral features of selected compounds known to be involved in the development of the eye disease age-related macular degeneration (AMD). Diagnostic features were identified in synthetic samples of these compounds and in a biological matrix. The study demonstrates the potential of Raman microscopy for the development of diagnostic markers of the onset of AMD. Copyright (C) 2008 John Wiley & Sons, Ltd.

Room-temperature ionic liquids as replacements for organic solvents in multiphase bioprocess operations

Organic solvents are widely used in a range of multiphase bioprocess operations including the liquid-liquid extraction of antibiotics and two-phase biotransformation reactions. There are, however, considerable problems associated with the safe handling of these solvents which relate to their toxic and flammable nature. In this work we have shown for the first time that room-temperature ionic liquids, such as 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6], can be successfully used in place of conventional solvents for the liquid-liquid extraction of erythromycin-A and for the Rhodococcus R312 catalyzed biotransformation of 1,3-dicyanobenzene (1,3-DCB) in a liquid-liquid, two-phase system. Extraction of erythromycin with either butyl acetate or [bmim][PF6] showed that values of the equilibrium partition coefficient, K, up to 20-25 could be obtained for both extractants. The variation of K with the extraction pH was also similar in the pH range 5-9 though differed significantly at higher pH values. Biotransformation of 1,3-DCB in both water-toluene and water-[bmim][PF6] systems showed similar profiles for the conversion of 1,3-DCB initially to 3-cyanobenzamide and then 3-cyanobenzoic acid. The initial rate of 3-cyanobenzamide production in the water-[bmim][PF6] system was somewhat lower, however, due to the reduced rate of 1,3-DCB mass transfer from the more viscous [bmim] [PF,] phase. it was also shown that the specific activity of the biocatalyst in the water-[bmim][PF6] system was almost an order of magnitude greater than in the water-toluene system which suggests that the rate of 3-cyanobenzamide production was limited by substrate mass transfer rather than the activity of the biocatalyst. (C) 2000 John Wiley & Sons, Inc.

Extraction of cesium ions from aqueous solutions using calix[4]arene-bis(tert-octylbenzo-crown-6) in ionic liquids

Solvent extraction of cesium ions from aqueous solution to hydrophobic ionic liquids without the introduction of an organophilic anion in the aqueous phase was demonstrated using calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) as an extractant. The selectivity of this extraction process toward cesium ions and the use of a sacrificial cation exchanger (NaBPh4) to control loss of imidazolium cation to the aqueous solutions by ion exchange have been investigated.

Mixed-dimensional coupling in finite element models

In many finite element analysis models it would be desirable to combine reduced- or lower-dimensional element types with higher-dimensional element types in a single model. In order to achieve compatibility of displacements and stress equilibrium at the junction or interface between the differing element types, it is important in such cases to integrate into the analysis some scheme for coupling the element types. A novel and effective scheme for establishing compatibility and equilibrium at the dimensional interface is described and its merits and capabilities are demonstrated. Copyright (C) 2000 John Wiley & Sons, Ltd.

Inter- and intrapersonal processes underlying authoritarianism: The role of social conformity and personal need for structure

Several personality constructs have been theorised to underlie right-wing authoritarianism (RWA). In samples from New Zealand and Germany (Ns = 218, 259), we tested whether these constructs can account for specific variance in RWA. In both samples, social conformity and personal need for structure were independent predictors of RWA. In Sample 2, where also openness to experience was measured, social conformity and personal need for structure fully mediated the impact of the higher-order factor of openness on RWA. Our results contribute to the integration of current approaches to the personality basis of authoritarianism. and suggest that two distinct personality processes contribute to RWA: An interpersonal process related to social conformity and an intrapersonal process related to rigid cognitive style. Copyright (C) 2009 John Wiley & Sons, Ltd.

Right-wing authoritarianism, social dominance orientation and prejudice against threatening and competitive ethnic groups

This research rests on the assumption that individual differences approaches to prejudice benefit from all integration of intergroup factors. Following Duckitt (2001), we assumed that two prominent individual differences variables, right-wing authoritarianism (RWA) and social dominance orientation (SDO), would differentially predict majority members' levels of ethnic prejudice depending on specific factors of the intergroup context: RWA as all index of motivational concerns about social cohesion, stability and security should drive prejudice against outgroups perceived as socially threatening, and SDO as an index of concerns about ingroup superiority and dominance should predict prejudice against outgroups perceived as potential competitors for power-status. Across two studies (Ns = 82, 176), using between-participants and within-participants experimental designs, the effects of RWA on prejudice were particularly powerful when the outgroup was manipulated to be socially threatening, but the effects of SDO on prejudice appeared not to increase when the outgroup was manipulated to be competitive. In Study 2, presenting the outgroup as having low status also increased the effect of RWA, but not the effect of SDO. These results support the differential prediction assumption for RWA, but not for SDO. Implications for the conceptualisation of RWA and SDO are discussed. Copyright (C) 2008 John Wiley & Sons, Ltd.

The police officer's terrorist dilemma: Trust resilience following fatal errors

Suicide attacks have raised the stakes for officers deciding whether or not to shoot a suspect ('Police Officer's Terrorist Dilemma'). Despite high-profile errors we know little about how trust in the police is affected by their response to the terrorist threat. Building on a conceptualisation of lay observers as intuitive signal detection theorists, a general population sample (N= 1153) were presented with scenarios manipulated in terms of suspect status (Armed/Unarmed), officer decision (Shoot/Not Shoot) and outcome severity (e.g. suspect armed with Bomb/Knife; police shoot suspect/ suspect plus child bystander). Supporting predictions, people showed higher trust in officers who made correct decisions. reflecting good discrimination ability and who decided to shoot, reflecting an 'appropriate' response bias given the relative costs and benefits. This latter effect was moderated by (a) outcome severity, suggesting it did not simply reflect a preference for a particular type of action, and (b) preferences for a tough stance towards terrorism indexed by Right-Wing Authoritarianism (RWA). Despite loss of civilian life, failure to prevent minor terror attacks resulted in no loss of trust amongst people low in RWA. whereas among people high in RWA trust was positive when police erroneously shot all unarmed suspect. Relations to alternative definitions of trust and procedural justice research are discussed. Copyright (C),. 2007 John Wiley & Sons, Ltd.

Is regret for inaction relatively self-enhancing?

Previous accounts of regret suggest that people report greater regret for inaction than for action because the former is longer lasting and more painful than the latter. We suggest instead that the tendency for people's greatest regrets to concern inaction more than action may be due to the relatively self-enhancing nature of regrets for inaction. In Study I we asked people to think about their greatest recent regret and to code it as being due to action or inaction. In Study 2 participants described their greatest regret from across their entire life. In both studies we observed an inaction effect only amongst individuals high in self-esteem (HSE). In Study 2 we found that the inaction effect was confined to HSE people whose greatest regret was personal in nature. These results support the claim that regret for inaction is relatively self-enhancing and suggest that the inaction effect found in real-life regrets may be due, in part at least, to the self-enhancement goals of HSE individuals. Copyright (c) 2005 John Wiley & Sons, Ltd.

The replacement of a native freshwater amphipod by an invader: roles for environmental degradation and intraguild predation

We assessed the extent to which an invader, Gammarus pulex (Crustacea: Amphipoda), has replaced a native, Gammarus duebeni celticus, over a 13-year period in a European river system and some of the abiotic and biotic factors that could account for this. Between 1988 and 2001, 56% of mixed-species sites had become invader-only sites, whereas no mixed sites had become native only again. The native dominated areas of higher dissolved oxygen and water quality, with the reciprocal true for the invader. Field transplant experiments revealed that native survivorship was lower in areas where it had been replaced than in areas where the invader does not yet occur. In invader-only areas, native survivorship was lower than that of the invader when kept separately and lowest when both species were kept together. We also observed predation of the native by the invader. Laboratory oxygen manipulation experiments revealed that at 30% saturation, the native's survivorship was two thirds that of the invader. We conclude that decreasing water quality favours replacement of the native by the invader.