Proton pumping by complex I (NADH : ubiquinone oxidoreductase) from Yarrowia lipolytica reconstituted into proteoliposomes

The mechanism of energy converting NADH:ubiquinone oxidoreductase (complex 1) is Still unknown. A current controversy centers around the question whether electron transport of complex I is always linked to vectorial proton translocation or whether in some organisms the enzyme pumps sodium ions instead. To develop better experimental tools to elucidate its mechanism, we have reconstituted the affinity purified enzyme into proteoliposomes and monitored the generation of Delta pH and Delta psi. We tested several detergents to solubilize the asolectin used for liposome formation. Tightly coupled proteoliposomes containing highly active complex I were obtained by detergent removal with BioBeads after total solubilization or the phospholipids with n-octyl-beta-D-glucopyranoside. We have used dyes to monitor the formation of the two components of the proton motive force, Delta pH and Delta psi, across the liposomal membrane, and analyzed the effects of inhibitors, uncouplers and ionophores on this process. We show that electron transfer of complex I of the lower eukaryote Y. lipolytica is clearly linked to proton translocation. While this study was not specifically designed to demonstrate possible additional sodium translocating properties of complex 1, we did not find indications for primary or secondary Na+ translocation by Y lipolytica complex I. (c) 2005 Elsevier B.V. All rights reserved.

Managing i-branding to create brand equity

Purpose: Given the emergent nature of i-branding as an academic field of study and a lack of applied research output, the aim of this paper is to explain how businesses manage i-branding to create brand equity.

Design/methodology/approach: Within a case-study approach, seven cases were developed from an initial sample of 20 food businesses. Additionally, utilising secondary data, the analysis of findings introduces relevant case examples from other industrial sectors.

Findings: Specific internet tools and their application are discussed within opportunities to create brand equity for products classified by experience, credence and search characteristics. An understanding of target customers will be critical in underpinning the selection and deployment of relevant i-branding tools. Tools facilitating interactivity – machine and personal – are particularly significant.

Research limitations/implications: Future research positioned within classification of goods constructs could provide further contributions that recognise potential moderating effects of product/service characteristics on the development of brand equity online. Future studies could also employ the i-branding conceptual framework to test its validity and develop it further as a means of explaining how i-branding can be managed to create brand equity.

Originality/value: While previous research has focused on specific aspects of i-branding, this paper utilises a conceptual framework to explain how diverse i-branding tools combine to create brand equity. The literature review integrates fragmented literature around a conceptual framework to produce a more coherent understanding of extant thinking. The location of this study within a classification of goods context proved critical to explaining how i-branding can be managed.

WASP-3b: a strongly irradiated transiting gas-giant planet

We report the discovery of WASP-3b, the third transiting exoplanet to be discovered by the WASP and SOPHIE collaboration. WASP-3b transits its host star USNO-B1.01256-0285133 every 1.846834 +/- 0.000002 d. Our high-precision radial velocity measurements present a variation with amplitude characteristic of a planetary-mass companion and in phase with the light curve. Adaptive optics imaging shows no evidence for nearby stellar companions, and line-bisector analysis excludes faint, unresolved binarity and stellar activity as the cause of the radial velocity variations. We make a preliminary spectroscopic analysis of the host star and find it to have Teff = 6400 +/- 100K and log g = 4.25 +/- 0.05 which suggests it is most likely an unevolved main-sequence star of spectral type F7-8V. Our simultaneous modelling of the transit photometry and reflex motion of the host leads us to derive a mass of 1.76+0.08-0.14 MJ and radius 1.31+0.07-0.14 RJ for WASP-3b. The proximity and relative temperature of the host star suggests that WASP-3b is one of the hottest exoplanets known, and thus has the potential to place stringent constraints on exoplanet atmospheric models.

Antibacterial activities of naturally occurring compounds against Mycobacterium avium subsp. paratuberculosis.

The antibacterial activities of 18 naturally occurring compounds (including essential oils and some of their isolated constituents, apple and green tea polyphenols, and other plant extracts) against three strains of Mycobacterium avium subsp. paratuberculosis (a bovine isolate [NCTC 8578], a raw-milk isolate [806R], and a human isolate [ATCC 43015]) were evaluated using a macrobroth susceptibility testing method. M. avium subsp. paratuberculosis was grown in 4 ml Middlebrook 7H9 broth containing 10% oleic acid-albumin-dextrose-catalase, 0.05% Tween 80 (or 0.2% glycerol), and 2 µg/ml mycobactin J supplemented with five concentrations of each test compound. The changes in the optical densities of the cultures at 600 nm as a measure of CFU were recorded at intervals over an incubation period of 42 days at 37°C. Six of the compounds were found to inhibit the growth of M. avium subsp. paratuberculosis. The most effective compound was trans-cinnamaldehyde, with a MIC of 25.9 µg/ml, followed by cinnamon oil (26.2 µg/ml), oregano oil (68.2 µg/ml), carvacrol (72.2 µg/ml), 2,5-dihydroxybenzaldehyde (74 µg/ml), and 2-hydroxy-5-methoxybenzaldehyde (90.4 µg/ml). With the exception of carvacrol, a phenolic compound, three of the four most active compounds are aldehydes, suggesting that the structure of the phenolic group or the aldehyde group may be important to the antibacterial activity. No difference in compound activity was observed between the three M. avium subsp. paratuberculosis strains studied. Possible mechanisms of the antimicrobial effects are discussed.

A Transit Timing Analysis of Mine RISE Light Curves of the Exoplanet System TrES-3

We present nine newly observed transits of TrES-3, taken as part of a transit timing program using the RISE instrument on the Liverpool Telescope. A Markov-Chain Monte Carlo analysis was used to determine the planet star radius ratio and inclination of the system, which were found to be R-p/R-star = 0.1664(-0.0018)(+0.0011) and i = 81.73(-0.04)(+0.13), respectively, consistent with previous results. The central transit times and uncertainties were also calculated, using a residual-permutation algorithm as an independent check on the errors. A re-analysis of eight previously published TrES-3 light curves was conducted to determine the transit times and uncertainties using consistent techniques. Whilst the transit times were not found to be in agreement with a linear ephemeris, giving chi(2) = 35.07 for 15 degrees of freedom, we interpret this to be the result of systematics in the light curves rather than a real transit timing variation. This is because the light curves that show the largest deviation from a constant period either have relatively little out-of-transit coverage or have clear systematics. A new ephemeris was calculated using the transit times and was found to be T-c(0) = 2454632.62610 +/- 0.00006 HJD and P = 1.3061864 +/- 0.0000005 days. The transit times were then used to place upper mass limits as a function of the period ratio of a potential perturbing planet, showing that our data are sufficiently sensitive to have probed sub-Earth mass planets in both interior and exterior 2:1 resonances, assuming that the additional planet is in an initially circular orbit.

Dual-task interference: Attentional and neurophysiological influences

Performing two tasks simultaneously often degrades performance of one or both tasks. While this dual-task interference is classically interpreted in terms of shared attentional resources, where two motor tasks are performed simultaneously interactions within primary motor cortex (i.e., activity-dependent coupling) may also be a contributing factor. In the present study TMS (transcranial magnetic stimulation) was used to examine the contribution of activity-dependent coupling to dual-task interference during concurrent performance of a bimanual coordination task and a discrete probe reaction time (RT) task involving the foot. Experiments 1 and 2 revealed that activity-dependent coupling within the leg corticomotor pathway was greater during dual-task performance than single-task performance, and this was associated with interference on the probe RT task (i.e., increased RT). Experiment 3 revealed that dual-task interference occurred regardless of whether the dual-task involved two motor tasks or a motor and cognitive task, however activity-dependent coupling was present only when a dual motor task was performed. This suggests that activity-dependent coupling is less detrimental to performance than attentional processes operating upstream of the corticomotor system. Finally, while prioritising the RT task reduced, but did not eliminate, dual-task interference the contribution of activity-dependent coupling to dual-task interference was not affected by task prioritisation. This suggests that although activity-dependent coupling may contribute to dual motor-task interference, attentional processes appear to be more important. It also suggests that activity-dependent coupling may not be subject to modulation by attentional processes. (C) 2009 Elsevier B.V. All rights reserved.

Effective suppression of bystander effects by DMSO treatment of irradiated CHO cells

Evidence is accumulating that irradiated cells produce some signals which interact with non-exposed cells in the same population via a bystander effect. Here, we examined whether DMSO is effective in suppressing radiation induced bystander effects in CHO and repair deficient xrs5 cells. When 1 Gy-irradiated CHO cells were treated with 0.5% DMSO for 1 hr before irradiation, the induction of micronuclei in irradiated cells was suppressed to 80% of that in non-treated irradiated cells. The suppressive effect of DMSO on the formation of bystander signals was examined and the results demonstrated that 0.5% DMSO treatment of irradiated cells completely suppressed the induction of micronuclei by the bystander effect in non-irradiated cells. It is suggested that irradiated cells ceased signal formation for bystander effects by the action of DMSO. To determine the involvement of reactive oxygen species on the formation of bystander signals, we examined oxidative stress levels using the DCFH staining method in irradiated populations. The results showed that the treatment of irradiated cells with 0.5% DMSO did not suppress oxidative stress levels. These results suggest that the prevention of oxidative stress is independent of the suppressive effect of DMSO on the formation of the bystander signal in irradiated cells. It is suggested that increased ROS in irradiated cells is not a substantial trigger of a bystander signal.

Nanohole array as a lens

We demonstrate that a quasi-crystal array of nanoholes in a metal screen can mimic a function of the lens: one-to-one imaging of a point source located a few tens of wavelengths away from the array to a point on the other side of the array. A displacement of the point source leads to a linear displacement of the image point. Complex structures composed of multiple point sources can be faithfully imaged with resolutions comparable to those of high numerical aperture lenses.

The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts

Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project - and avert - future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups - including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems - http://www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.

Interleukin-8 and its receptor CXCR2 in the tumour microenvironment promote colon cancer growth, progression and metastasis

BACKGROUND: Colorectal cancer (CRC) is a leading cause of death in the United States. Increased level of interleukin-8 (IL-8) and CXCR2 on tumours and in the tumour microenvironment has been associated with CRC growth, progression and recurrence in patients. Here, we aimed to evaluate the effects of tissue microenvironment-encoded IL-8 and CXCR2 on colon cancer progression and metastasis.

METHODS: A novel immunodeficient, skin-specific IL-8-expressing transgenic model was generated to evaluate colon cancer growth and metastasis. Syngeneic mouse colon cancer cells were grafted in CXCR2 knockout (KO) mice to study the contribution of CXCR2 in the microenvironment to cancer growth.

RESULTS: Elevated levels of IL-8 in the serum and tumour microenvironment profoundly enhanced the growth of human and mouse colon cancer cells with increased peri-tumoural angiogenesis, and also promoted the extravasation of the cancer cells into the lung and liver. The tumour growth was inhibited in CXCR2 KO mice with significantly reduced tumour angiogenesis and increased tumour necrosis.

CONCLUSION: Increased expression of IL-8 in the tumour microenvironment enhanced colon cancer growth and metastasis. Moreover, the absence of its receptor CXCR2 in the tumour microenvironment prevented colon cancer cell growth. Together, our study demonstrates the critical roles of the tumour microenvironment-encoded IL-8/CXCR2 in colon cancer pathogenesis, validating the pathway as an important therapeutic target.

A coactivator role of CARM1 in the dysregulation of β-catenin activity in colorectal cancer cell growth and gene expression

Aberrant activation of Wnt/β-catenin signaling, resulting in the expression of Wnt-regulated oncogenes, is recognized as a critical factor in the etiology of colorectal cancer. Occupancy of β-catenin at promoters of Wnt target genes drives transcription, but the mechanism of β-catenin action remains poorly understood. Here, we show that CARM1 (coactivator-associated arginine methyltransferase 1) interacts with β-catenin and positively modulates β-catenin-mediated gene expression. In colorectal cancer cells with constitutively high Wnt/β-catenin activity, depletion of CARM1 inhibits expression of endogenous Wnt/β-catenin target genes and suppresses clonal survival and anchorage-independent growth. We also identified a colorectal cancer cell line (RKO) with a low basal level of β-catenin, which is dramatically elevated by treatment with Wnt3a. Wnt3a also increased the expression of a subset of endogenous Wnt target genes, and CARM1 was required for the Wnt-induced expression of these target genes and the accompanying dimethylation of arginine 17 of histone H3. Depletion of β-catenin from RKO cells diminished the Wnt-induced occupancy of CARM1 on a Wnt target gene, indicating that CARM1 is recruited to Wnt target genes through its interaction with β-catenin and contributes to transcriptional activation by mediating events (including histone H3 methylation) that are downstream from the actions of β-catenin. Therefore, CARM1 is an important positive modulator of Wnt/β-catenin transcription and neoplastic transformation, and may thereby represent a novel target for therapeutic intervention in cancers involving aberrantly activated Wnt/β-catenin signaling.