Functional heterogeneity of the UpaH autotransporter protein from Uropathogenic Escherichia coli

Uropathogenic Escherichia coli (UPEC) is responsible for the majority of urinary tract infections (UTI). To cause a UTI, UPEC must adhere to the epithelial cells of the urinary tract and overcome the shear flow forces of urine. This function is mediated primarily by fimbrial adhesins, which mediate specific attachment to host cell receptors. Another group of adhesins that contributes to UPEC-mediated UTI is autotransporter (AT) proteins. AT proteins possess a range of virulence properties, such as adherence, aggregation, invasion, and biofilm formation. One recently characterized AT protein of UPEC is UpaH, a large adhesin-involved-in-diffuse-adherence (AIDA-I)-type AT protein that contributes to biofilm formation and bladder colonization. In this study we characterized a series of naturally occurring variants of UpaH. We demonstrate that extensive sequence variation exists within the passenger-encoding domain of UpaH variants from different UPEC strains. This sequence variation is associated with functional heterogeneity with respect to the ability of UpaH to mediate biofilm formation. In contrast, all of the UpaH variants examined retained a conserved ability to mediate binding to extracellular matrix (ECM) proteins. Bioinformatic analysis of the UpaH passenger domain identified a conserved region (UpaHCR) and a hydrophobic region (UpaHHR). Deletion of these domains reduced biofilm formation but not the binding to ECM proteins. Despite variation in the upaH sequence, the transcription of upaH was repressed by a conserved mechanism involving the global regulator H-NS, and mutation of the hns gene relieved this repression. Overall, our findings shed new light on the regulation and functions of the UpaH AT protein.

Molecular characterization of the EhaG and UpaG trimeric autotransporter proteins from pathogenic Escherichia coli

Trimeric autotransporter proteins (TAAs) are important virulence factors of many Gram-negative bacterial pathogens. A common feature of most TAAs is the ability to mediate adherence to eukaryotic cells or extracellular matrix (ECM) proteins via a cell surface-exposed passenger domain. Here we describe the characterization of EhaG, a TAA identified from enterohemorrhagic Escherichia coli (EHEC) O157:H7. EhaG is a positional orthologue of the recently characterized UpaG TAA from uropathogenic E. coli (UPEC). Similarly to UpaG, EhaG localized at the bacterial cell surface and promoted cell aggregation, biofilm formation, and adherence to a range of ECM proteins. However, the two orthologues display differential cellular binding: EhaG mediates specific adhesion to colorectal epithelial cells while UpaG promotes specific binding to bladder epithelial cells. The EhaG and UpaG TAAs contain extensive sequence divergence in their respective passenger domains that could account for these differences. Indeed, sequence analyses of UpaG and EhaG homologues from several E. coli genomes revealed grouping of the proteins in clades almost exclusively represented by distinct E. coli pathotypes. The expression of EhaG (in EHEC) and UpaG (in UPEC) was also investigated and shown to be significantly enhanced in an hns isogenic mutant, suggesting that H-NS acts as a negative regulator of both TAAs. Thus, while the EhaG and UpaG TAAs contain some conserved binding and regulatory features, they also possess important differences that correlate with the distinct pathogenic lifestyles of EHEC and UPEC.

Innate transcriptional networks activated in bladder in response to uropathogenic Escherichia coli drive diverse biological pathways and rapid synthesis of IL-10 for defense against bacterial urinary tract infection

Early transcriptional activation events that occur in bladder immediately following bacterial urinary tract infection (UTI) are not well defined. In this study, we describe the whole bladder transcriptome of uropathogenic Escherichia coli (UPEC) cystitis in mice using genome-wide expression profiling to define the transcriptome of innate immune activation stemming from UPEC colonization of the bladder. Bladder RNA from female C57BL/6 mice, analyzed using 1.0 ST-Affymetrix microarrays, revealed extensive activation of diverse sets of innate immune response genes, including those that encode multiple IL-family members, receptors, metabolic regulators, MAPK activators, and lymphocyte signaling molecules. These were among 1564 genes differentially regulated at 2 h postinfection, highlighting a rapid and broad innate immune response to bladder colonization. Integrative systems-level analyses using InnateDB (http://www.innatedb.com) bioinformatics and ingenuity pathway analysis identified multiple distinct biological pathways in the bladder transcriptome with extensive involvement of lymphocyte signaling, cell cycle alterations, cytoskeletal, and metabolic changes. A key regulator of IL activity identified in the transcriptome was IL-10, which was analyzed functionally to reveal marked exacerbation of cystitis in IL-10–deficient mice. Studies of clinical UTI revealed significantly elevated urinary IL-10 in patients with UPEC cystitis, indicating a role for IL-10 in the innate response to human UTI. The whole bladder transcriptome presented in this work provides new insight into the diversity of innate factors that determine UTI on a genome-wide scale and will be valuable for further data mining. Identification of protective roles for other elements in the transcriptome will provide critical new insight into the complex cascade of events that underpin UTI.

Comparative analysis of FimB and FimE recombinase activity

FimB and FimE are site-specific recombinases, part of the λ integrase family, and invert a 314 bp DNA switch that controls the expression of type 1 fimbriae in Escherichia coli. FimB and FimE differ in their activity towards the fim switch, with FimB catalysing inversion in both directions in comparison to the higher-frequency but unidirectional on-to-off recombination catalysed by FimE. Previous work has demonstrated that FimB, but not FimE, recombination is completely inhibited in vitro and in vivo by a regulator, PapB, expressed from a distinct fimbrial locus. The aim of this work was to investigate differences between FimB and FimE activity by exploiting the differential inhibition demonstrated by PapB. The research focused on genetic changes to the fim switch that alter recombinase binding and its structural context. FimB and FimE still recombined a switch in which the majority of fimS DNA was replaced with a larger region of non-fim DNA. This demonstrated a minimal requirement for FimB and FimE recombination of the Fim binding sites and associated inverted repeats. With the original leucine-responsive regulatory protein (Lrp) and integration host factor (IHF)-dependent structure removed, PapB was now able to inhibit both recombinases. The relative affinities of FimB and FimE were determined for the four ‘half sites’. This analysis, along with the effect of extensive swaps and duplications of the half sites on recombination frequency, demonstrated that FimB recruitment and therefore subsequent activity was dependent on a single half site and its context, whereas FimE recombination was less stringent, being able to interact initially with two half sites with equally high affinity. While increasing FimB recombination frequencies failed to overcome PapB repression, mutations made in recombinase binding sites resulted in inhibition of FimE recombination by PapB. Overall, the data support a model in which the recombinases differ in loading order and co-operative interactions. PapB exploits this difference and FimE becomes susceptible when its normal loading is restricted or changed.

Deviant consumer behaviour : a qualitative exploration

Deviant behaviour is an ongoing problem in the consumer marketplace (Daunt and Harris, 2012). To investigate this issue, a number of authors have focused on empirically assessing consumer perceptions of right and wrong behaviours, such as the Muncy-Vitell (1992) consumer ethics scale. While studies like this have provided extensive empirical insights, qualitative insight into why consumers make these behaviour classifications remains underexplored. The aim of this paper is to extend on that literature by exploring the reasoning behind behavioural classifications. Using interviews, seven factors were identified in consumer definitions of acceptable, questionable, and unacceptable consumer behaviours including; official classification, prevalence, ease of justification, perceived fairness, consequences, risk, and values. These results also provide actionable insights for marketers in that multi-level deterrence strategies must be employed to more effectively deter consumer deviance, as opposed to traditional deterrence strategies based on cost-benefit analyses.

Dapsone-induced agranulocytosis. The role of xenobiotic-metabolizing enzymes demonstrated by a case report [Dapson-induzierte Agranulozytose]

A 34-year-old female patient with a three year history of generalized granuloma annulare was treated systemically with dapsone (DADPS). Six weeks after the onset of treatment, the patient developed an extensive tonsillitis of the base of the tongue with fever and malaise. Routine laboratory work showed a leukocytopenia with agranulocytosis. Further investigation revealed a marked decrease of the enzyme activity of N-acetyltransferase 2, which plays an important role in dapsone metabolism. Treatment included the cessation of dapsone, antibiotic coverage, and G-CSF leading to the rapid improvement of symptoms and normalization of leukocyte counts. Dapsone-induced angina agranulocytotica is a rare event and is interpreted as an idiosyncratic reaction. Depending on genetic polymorphisms of various enzymes, dapsone can be metabolized to immunologically or toxicologically relevant intermediates. Because of the risk of severe hematologic reactions, dapsone should only be employed for solid indications and with appropriate monitoring. [Article in German]

Ecionines A and B, two new cytotoxic pyridoacridine alkaloids from the Australian marine sponge, Ecionemia geodides

Chemical investigations of the Australian marine sponge Ecionemia geodides resulted in the isolation of two new pyridoacridine alkaloids, ecionines A (1) and B (2), along with the previously isolated marine natural products, biemnadin (3) and meridine (4). Compounds 1 and 2 both contain an imine moiety, which is rare for the pyridoacridine structure class. The chemical structures of 1 and 2 were determined by extensive 1D and 2D NMR and MS data analyses. All compounds were tested against a panel of human bladder cancer cell lines, the increasingly metastatic TSU-Pr1 series (TSU-Pr1, TSU-Pr1-B1 and TSU-Pr1- B2) and the superficial bladder cancer cell line 5637. Ecionine A (1) displayed cytotoxicity against all cell lines, with IC50 values ranging from 3 to 7 mM. This is the first report of chemistry from the sponge genus Ecionemia.

Evaluation of the potential impact of the global economic crisis on HIV epidemics in Southeast Asia

Economic conditions around the world are likely to deteriorate in the short to medium term. The potential impact of this crisis on the spread of HIV is not clear. Government revenues and aid flows from international donors may face constraints, possibly leading to reductions in funding for HIV programs. Economic conditions (leading to increases in unemployment, for example) may also have an indirect impact on HIV epidemics by affecting the behaviour of individual people. Some behavioural changes may influence the rate of HIV transmission. This report presents findings from a study that investigates the potential impact of the economic crisis on HIV epidemics through the use of mathematical modelling. The potential epidemiological impacts of changes in the economy are explored for two distinctly characterised HIV epidemics: (i) a well-defined, established, and generalised HIV epidemic (specifically Cambodia, where incidence is declining); (ii) an HIV epidemic in its early expansion phase (specifically Papua New Guinea, where incidence has not yet peaked). Country-specific data are used for both settings and the models calibrated to accurately reflect the unique HIV epidemics in each population in terms of both incidence and prevalence. Models calibrated to describe the past and present epidemics are then used to forecast epidemic trajectories over the next few years under assumptions that behavioural or program conditions may change due to economic conditions. It should be noted that there are very limited solid data on how HIV/AIDS program funds may decrease or how social determinants related to HIV risk may change due to the economic crisis. Potential changes in key relevant factors were explored, along with sensitivity ranges around these assumptions, based on extensive discussions with in-country and international experts and stakeholders. As with all mathematical models, assumptions should be reviewed critically and results interpreted cautiously.

Co-branding strategies for luxury fashion brands : Missoni for Target

Missoni is a luxury Italian knitwear brand that partnered with Target in September 2011 releasing a large, one off, mass-market collection that ranged from apparel to home wares. The collaboration received extensive media coverage and was consequently extremely sought after. The online sales site crashed within hours of opening while shelves were cleared in stores minutes after trading began. Within hours more than 40000 items from the collection were posted for sale online at greatly inflated prices. Evaluation of the case study revealed that sales of the Missoni collection increased following the collaboration and the value of the publicity generated at estimated US$100 million. The lack of available stock, despite the enormous hype created, reinforced Missoni’s luxury image. Missoni was able to gain massive awareness of the brand despite not employing any of its own communication channels in the promotion of the collaboration. However the co-branded collaboration was distinctively Missoni, potentially inciting comparison and confusion with the signature line. Nevertheless, this study shows that co-branding strategies can offer a viable opportunity for luxury brands to increase their market share, while they maintain their market position.

Empirical vehicle-to-vehicle pathloss modeling in highway, suburban and urban environments at 5.8GHz

In this paper, we present a pathloss characterization for vehicle-to-vehicle (V2V) communications based on empirical data collected from extensive measurement campaign performed under line-of-sight (LOS), non-line-of-sight (NLOS) and varying traffic densities. The experiment was conducted in three different V2V propagation environments: highway, suburban and urban at 5.8GHz. We developed pathloss models for each of the three different V2V environments considered. Based on a log-distance power law model, the values for the pathloss exponent and the standard deviation of shadowing were reported. The average pathloss exponent ranges from 1.77 for highway, 1.68 for the urban to 1.53 for the suburban environment. The reported results can contribute to vehicular network (VANET) simulators and can be used by system designers to develop, evaluate and validate new protocols and system designs under realistic propagation conditions.

Three essays on banks trading activities

With a fair share of the blame for the subprime crisis pointing to banks' extensive involvement in trading, this thesis examines three closely related issues. The first essay shows that regulatory capital arbitrage, insolvency risk, and non-interest income are all important motivations for banks to become involved in trading. The second essay support the widely held perception that trading activities such as off-balance sheet derivatives, securitization, and assets sales all are making banks more opaque. With banks' business model changing from ''originate and hold'' to ''originate, repackage, and sell'', the last essay show that trading channel exist and it has weakened the effectiveness of monetary policy transmission through banks' capital and lending channel.

Australian health and safety inspectors’ perceptions and actions in relation to changed work arrangements

Extensive international research points to an association between changed work arrangements, especially those commonly labelled as contingent work, with adverse occupational health and safety (OHS) outcomes. Research also indicates these work arrangements have weakened or bypassed existing OHS and workers’ compensation regulatory regimes. However, there has been little if any research into how OHS inspectors perceive these issues and how they address them during workplace visits or investigations. Between 2003 and 2007 research was undertaken that entailed detailed documentary and statistical analysis, extended interviews with 170 regulatory managers and inspectors, and observational data collected while accompanying inspectors on 118 ‘typical’ workplace visits. Key findings are that inspectors responsible for a range of industries see altered work arrangements as a serious challenge, especially labour hire (agency work) and subcontracting. Though the law imposes clear obligations, inspectors identified misunderstanding/blameshifting and poor compliance amongst parties to these arrangements. The complexity of these work arrangements also posed logistical challenges to inspectorates.

Qld flood inquest : ‘I could see his arms moving, he was trying to swim’

"Despite the 10 months of grieving for those lost in Queensland’s January floods, new evidence produced during the coronial inquest into the 22 deaths and three disappearances has revealed new shocks for the bereaved families. Brisbane Coroner’s Court yesterday was introduced to a series of high-tech Google Earth animations backed by funereal music, explaining the scope of the unfolding tragedy, which swept away husbands, wives, children and grandparents in less than three hours on the afternoon of January 10 this year. The court was also told of the extensive search for human remains, of 131 kilometres of creeks and rivers from Spring Bluff to Brisbane and hundreds of dams that were searched three times by police divers, 250 army personnel and 200 police."

Foundations for the future : A long-term plan for Australian ecosystem science

Abstract: Australia’s ecosystems are the basis of our current and future prosperity, and our national well-being.A strong and sustainable Australian ecosystem science enterprise is vital for understanding and securing these ecosystems in the face of current and future challenges. This Plan defines the vision and key directions for a national ecosystem science capability that will enable Australia to understand and effectively manage its ecosystems for decades to come.The Plan’s underlying theme is that excellent science supports a range of activities, including public engagement, that enable us to understand and maintain healthy ecosystems.Those healthy ecosystems are the cornerstone of our social and economic well-being.The vision guiding the development of this Plan is that in 20 years’ time the status of Australian ecosystems and how they change will be widely reported and understood, and the prosperity and well-being they provide will be secure. To enable this, Australia’s national ecosystem science capability will be coordinated, collaborative and connected.The Plan is based on an extensive set of collaboratively generated proposals from national town hall meetings that also formthe basis for its implementation. Some directions within the Plan are for the Australian ecosystem science community itself to implement, others will involve the users of ecosystem science and the groups that fund ecosystem science.We identify six equal priority areas for action to achieve our vision: (i) delivering maximum impact for Australia: enhancing relationships between scientists and end-users; (ii) supporting long-termresearch; (iii) enabling ecosystem surveillance; (iv) making the most of data resources; (v) inspiring a generation: empowering the public with knowledge and opportunities; (vi) facilitating coordination, collaboration and leadership. This shared vision will enable us to consolidate our current successes, overcome remaining barriers and establish the foundations to ensure Australian ecosystem science delivers for the future needs of Australia..

Power and paradigms : the Dutch response to pressures for shareholder value

In recent years, research aimed at identifying and relating the antecedents and consequences of diffusing organizational practices/ideas has turned its attention to debating the international adoption and implementation of the Anglo-American model of corporate governance, i.e., a shareholder-value-orientation (SVO). While financial economists characterize the adoption of an SVO as necessary and performance-enhancing, behavioral scientists have disputed such claims, invoking institutional contingencies in the appropriateness of an SVO. Our study seeks to provide some resolution to the debate by developing an overarching socio-political perspective that links the antecedents and consequences of the adoption of the contested practice of SVO. We test our framework using extensive longitudinal data from 1992-2006 from the largest listed corporations in the Netherlands, and we find a negative relationship between SVO adoption and subsequent firm performance, although this effect is attenuated when accompanied by greater SVO-alignment among major owners and a firm’s visible commitment to an SVO. This study extends prior research on the diffusion of contested organizational practices that has taken a socio-political perspective by offering an original contingency perspective that addresses how and why the misaligned preferences of corporate owners will affect (i) a company’s inclination to espouse an SVO, and (ii) the performance consequences of such misalignment.This study suggests when board members are considering the adoption of new ideas/practices (e.g., SVO), they should consider the contextual fitness of the idea/practice with the firm’s owners and their interests.