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The structures of two Dr adhesin (DraE) complexes with chloramphenicol derivatives, namely chloramphenicol succinate and bromamphenicol, have been solved. The structures reveal important functional groups for small-molecule binding and imply possible modifications to the molecule that would permit a more wide-ranging interaction without the toxic side effects associated with chloramphenicol., Dr adhesins are expressed on the surface of uropathogenic and diffusely adherent strains of Escherichia coli. The major adhesin subunit (DraE/AfaE) of these organelles mediates attachment of the bacterium to the surface of the host cell and possibly intracellular invasion through its recognition of the complement regulator decay-accelerating factor (DAF) and/or members of the carcinoembryonic antigen (CEA) family. The adhesin subunit of the Dr haemagglutinin, a Dr-family member, additionally binds type IV collagen and is inhibited in all its receptor interactions by the antibiotic chloram­phenicol (CLM). In this study, previous structural work is built upon by reporting the X-ray structures of DraE bound to two chloramphenicol derivatives: chloramphenicol succinate (CLS) and bromamphenicol (BRM). The CLS structure demonstrates that acylation of the 3-hydroxyl group of CLM with succinyl does not significantly perturb the mode of binding, while the BRM structure implies that the binding pocket is able to accommodate bulkier substituents on the N-­acyl group. It is concluded that modifications of the 3-­hydroxyl group would generate a potent Dr haemagglutinin inhibitor that would not cause the toxic side effects that are associated with the normal bacteriostatic activity of CLM.

Complement component C8 plays a pivotal role in the formation of the membrane attack complex (MAC), an important antibacterial immune effector. C8 initiates membrane penetration and coordinates MAC pore formation. High-resolution structures of C8 subunits have provided some insight into the function of the C8 heterotrimer; however, there is no structural information describing how the intersubunit organization facilitates MAC assembly. We have determined the structure of C8 by electron microscopy and fitted the C8α-MACPF (membrane attack complex/perforin)-C8γ co-crystal structure and a homology model for C8β-MACPF into the density. Here, we demonstrate that both the C8γ protrusion and the C8α-MACPF region that inserts into the membrane upon activation are accessible., Graphical Abstract Research Highlights ► Complement component C8 initiates membrane penetration of the membrane attack complex, an important innate immune effector. ► The structure of C8 reveals a core domain with a globular protrusion. ► Docking of pseudo-atomic models into the electron microscopy reconstruction indicates that C8γ projects away from the C8αβ core, in which the predicted transmembrane residues of C8α-MACPF and one face of the C8β-MACPF are surface exposed.

MxiG is a single-pass membrane protein that oligomerizes within the inner membrane ring of the Shigella flexneri type III secretion system (T3SS). The MxiG N-terminal domain (MxiG-N) is the predominant cytoplasmic structure; however, its role in T3SS assembly and secretion is largely uncharacterized. We have determined the solution structure of MxiG-N residues 6-112 (MxiG-N(6-112)), representing the first published structure of this T3SS domain. The structure shows strong structural homology to forkhead-associated (FHA) domains. Canonically, these cell-signaling modules bind phosphothreonine (Thr(P)) via highly conserved residues. However, the putative phosphate-binding pocket of MxiG-N(6-112) does not align with other FHA domain structures or interact with Thr(P). Furthermore, mutagenesis of potential phosphate-binding residues has no effect on S. flexneri T3SS assembly and function. Therefore, MxiG-N has a novel function for an FHA domain. Positioning of MxiG-N(6-112) within the EM density of the S. flexneri needle complex gives insight into the ambiguous stoichiometry of the T3SS, supporting models with 24 MxiG subunits in the inner membrane ring. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.

Centrioles are among the most beautiful of biological structures. How their highly conserved nine-fold symmetry is generated is a question that has intrigued cell biologists for decades. Two recent structural studies provide the tantalizing suggestion that the self-organizing properties of the SAS-6 protein hold the answer.

In a field where structure has finally begun to have a real impact, a series of new structures over the last two years have further extended our understanding of some of the critical regulatory events of the complement system. Notably, information has begun to flow from larger assemblies of components which allow insight into the often transient assemblies critical to complement regulation at the cell surface. This review will summarise the key structures determined since the last International Complement Workshop and the insights these have given us, before highlighting some questions that still require molecular frameworks to drive understanding.

Factor I (FI) is a crucial inhibitor controlling all complement pathways due to its ability to degrade activated complement proteins C3b and C4b in the presence of cofactors such as factor H, C4b-binding protein, complement receptor 1 or CD46. Complete deficiency of FI, which is synthesized mainly in the liver is rare and leads to complement consumption resulting in recurrent severe infections, glomerulonephritis or autoimmune diseases. Incomplete FI deficiency is in turn associated with atypical haemolytic uremic syndrome, a severe disease characterized by thrombocytopenia, microangiopathic haemolytic anaemia and acute renal failure. Structurally, FI is a 88kDa heterodimer of a heavy chain consisting of one FI-membrane attack complex (FIMAC) domain, one CD5 domain and two low-density lipoprotein receptor domains (LDLr), and a light chain which is a serine protease domain (SP), linked to the heavy chain by a disulfide bond. FI cleaves its in vivo substrates C3b and C4b only in the presence of cofactors, it shows poor enzymatic activity towards synthetic substrates tested so far and it has no natural inhibitor.

Nearly 50 million people worldwide suffer from age-related macular degeneration (AMD), which causes severe loss of central vision. A single-nucleotide polymorphism in the gene for the complement regulator factor H (FH), which causes a Tyr-to-His substitution at position 402, is linked to ∼50% of attributable risks for AMD. We present the crystal structure of the region of FH containing the polymorphic amino acid His402 in complex with an analogue of the glycosaminoglycans (GAGs) that localize the complement regulator on the cell surface. The structure demonstrates direct coordination of ligand by the disease-associated polymorphic residue, providing a molecular explanation of the genetic observation. This glycan-binding site occupies the center of an extended interaction groove on the regulator's surface, implying multivalent binding of sulfated GAGs. This finding is confirmed by structure-based site-directed mutagenesis, nuclear magnetic resonance–monitored binding experiments performed for both H402 and Y402 variants with this and another model GAG, and analysis of an extended GAG–FH complex.

Background: The site of Jagged/Serrate ligand recognition by Notch is unknown. Results: Two critical residues involved in an intramolecular hydrophobic interaction across the central β-sheet of EGF12 form a ligand-binding platform. Conclusion: The ligand-binding region is adjacent to a Fringe-sensitive residue involved in modulating Notch activity. Significance: The results have implications for understanding receptor/ligand recognition, Notch regulation by O-glycosylation, and the development of paralogue-specific antibodies., We have mapped a Jagged/Serrate-binding site to specific residues within the 12th EGF domain of human and Drosophila Notch. Two critical residues, involved in a hydrophobic interaction, provide a ligand-binding platform and are adjacent to a Fringe-sensitive residue that modulates Notch activity. Our data suggest that small variations within the binding site fine-tune ligand specificity, which may explain the observed sequence heterogeneity in mammalian Notch paralogues, and should allow the development of paralogue-specific ligand-blocking antibodies. As a proof of principle, we have generated a Notch-1-specific monoclonal antibody that blocks binding, thus paving the way for antibody tools for research and therapeutic applications.

Activation of complement C5 generates the potent anaphylatoxin C5a and leads to pathogen lysis, inflammation and cell damage. The therapeutic potential of C5 inhibition has been demonstrated by eculizumab, one of the world's most expensive drugs. However, the mechanism of C5 activation by C5 convertases remains elusive, thus limiting development of therapeutics. Here we identify and characterize a new protein family of tick-derived C5 inhibitors. Structures of C5 in complex with the new inhibitors, the phase I and phase II inhibitor OmCI, or an eculizumab Fab reveal three distinct binding sites on C5 that all prevent activation of C5. The positions of the inhibitor-binding sites and the ability of all three C5-inhibitor complexes to competitively inhibit the C5 convertase conflict with earlier steric-inhibition models, thus suggesting that a priming event is needed for activation.

This study investigated the social construction of domestic abuse by police officers, specifically in the context of arguments presented to the prosecutor for a decision on whether to proceed with or discontinue the case. Nineteen police files were examined with a particular focus on the MG3, the “Report to Crown Prosecutors for Charging Decision.” Access to such sensitive material is usually denied to researchers; therefore, this study offers unusual insights into the treatment of victims and perpetrators of interpersonal violence by the police. Discourse analysis revealed three dominant speech genres: impartiality, credibility, and the “real” victim. These genres separately and in interaction served to construct domestic abuse cases in ways that did not support the victim’s account. The “dialogic reverberations” of these findings are discussed and the implications of the work for research and practice are considered.

A review of published tetartohedrally twinned macromolecular structures is presented, together with details of the recent structure determination of triclinic tetartohedrally twinned crystals of human complement factor I., Tetartohedral crystal twinning is discussed as a particular case of (pseudo)merohedral twinning when the number of twinned domains is four. Tetartohedrally twinned crystals often possess pseudosymmetry, with the rotational part of the pseudo­symmetry operators coinciding with the twinning operators. Tetartohedrally twinned structures from the literature are reviewed and the recent structure determination of tetartohedrally twinned triclinic crystals of human complement factor I is discussed.

Summary Background and objectives Atypical hemolytic uremic syndrome is a disease associated with mutations in the genes encoding the complement regulators factors H and I. In addition, factor H autoantibodies have been reported in ;10% of patients with atypical hemolytic uremic syndrome. This study searched for the presence of factor I autoantibodies in atypical hemolytic uremic syndrome. Design, setting, participants, & measurements This study screened 175 atypical hemolytic uremic syndrome patients for factor I autoantibodies using ELISA with confirmatory Western blotting. Functional studies using purified immunoglobulin from one patient were subsequently undertaken. ResultsFactor Iautoantibodieswere detectedinthree patients.Inone patient withah ightiterofautoantibody, the titer was tracked over time and was found to have no association with disease activity. This study found evidence of animmune complex of antibody and factor Ii nthis patient,but purifiedIgG,isolated from current serum samples, had only a minor effect on fluid phase and cell surface complement regulation. Genetic analysis of the three patients with factor I autoantibodies revealed that they had two copies of the genes encoding factor H–related proteins 1 and 3 and therefore, did no th ave ad eletion commonly associated with factor H autoantibodies in atypical hemolytic uremic syndrome. Two patients, however, had functionally significant mutations in complement factor H. Conclusions These findings reinforce the concept of multiple concurrent risk factors being associated with atypical hemolytic uremic syndrome but question whether autoantibodies per se predispose to atypical hemolytic uremic syndrome. Clin J Am Soc Nephrol 7: 417–426, 2012. doi: 10.2215/CJN.05750611

Nick Lynn* and Susan J. LeaThis paper explores the rhetorical skills or witcraft of police officers as they adjudicate on disputesand crimes reported to them. The first author accompaniedofficers ‘on the beat’ to record these inter-actions with members of the public. A discourse analysis of the data revealed officers regularly usea discursive strategy that we term the that’s civil device. Exploiting an epistemological imbalancethat exists in police/public interactions, the device not only allows officers to externalize their judg-ments as matters of law; it also assists them to manage the conversationally and operationally dif-ficult task of refusing. Moreover, it allows officers to resist claims of disinterestedness or neglect ofduty as they limit or disbar their involvement in potentially insoluble disputes.Keywords: police, crime recording, witcraft, refusals, stake, powerIntroductionUniformed police work has a reputation for being exciting (Holdaway 1977). On a dailybasis, the media present ‘front-line’ policing as both thrilling and risky. But, while thenature of policing means that it is always prone to the unexpected, dramatic events aregenerally the exception rather than the rule (Sykes and Brent 1983; McConville et al.1991; Reiner 2000). The day-to-day reality for uniformed officers is that much of whatthey do is mundane(Chan etal.2003). A substantial amount of time is spent resolving oradjudicating petty ‘disputes’ (Kemp et al. 1992), dealing with ‘nuisance’ children, de-terring ‘anti-social’ behaviour, locating missing persons, checking the welfare of vulner-able individuals, acting on behalf of the Coroner in dealing with so-called ‘sudden’deaths and recording crimes that members of the public report to them (Banton1964; Shapland and Vagg 1988). The banal nature of this work is often overlooked;yet, if we are to increase our understanding of how police officers do policing, it is fromstudyingthecommonplaceandtheapparentlyuninterestingthatwemaygainourgreat-est insights (Billig 1995).In this paper, we concentrate our attention on how officers evaluate and categorizethe disputes they deal with and how it is that some are recorded as crimes and others arenot.Whileonemightassumethatsuchdecisionswould,ingeneral,be relativelystraight-forward, the combination of professional expertise, discretion and a mix of pragmatic,situational and ideological considerations mean that the recording of crime is more ofan art rather than a dry bureaucratic task (Shapland and Vagg 1988). The police, asCicourel found, will account for how they deal with an event, ‘in such a way that theirpresence or interference can be warranted now and later on if further justification isrequired’ (Cicourel 1968: 112).

The structure of rat CrrY1–4 determined in two distinct crystal forms shows a pronounced bend at the interface between domains 3 and 4., Complement receptor 1-related protein Y (CrrY) is an important cell-surface regulator of complement that is unique to rodent species. The structure of rat CrrY domains 1–4 has been determined in two distinct crystal forms and reveals a 70° bend between domains 3 and 4. Comparisons of this structure with those of other complement regulators suggests that rearrangement of this interface may occur on forming the regulatory complex with C3b.

Objective Nurses need to be competent and confident in performing drug calculations to ensure patient safety. The purpose of this study is to compare an interactive e-drug calculations package, developed using Cognitive Load Theory as its theoretical framework, with traditional handout learning support on nursing students' drug calculation ability, self-efficacy and support material satisfaction. Design A cluster randomised controlled trial comparing the e-package with traditional handout learning support was conducted with a September cohort ( n =137) and a February cohort ( n =92) of second year diploma nursing students. Students from each cohort were geographically dispersed over 3 or 4 independent sites. Measurements Students from each cohort were invited to participate, halfway through their second year, before and after a 12 week clinical practice placement. During their placement the intervention group received the e-drug calculations package while the control group received traditional ‘handout' support material. Drug calculation ability and self-efficacy tests were given to the participants pre- and post-intervention. Participants were given the support material satisfaction scale post-intervention. Results Students in both cohorts randomised to e-learning were more able to perform drug calculations than those receiving the handout (September: mean 48.4% versus 34.7%, p =0.027; February: mean 47.6% versus 38.3%, p =0.024). February cohort students using the e-package were more confident in performing drug calculations than those students using handouts (self-efficacy mean 56.7% versus 45.8%, p =0.022). There was no difference in improved self-efficacy between intervention and control for students in the September cohort. Students who used the package were more satisfied with its use than the students who used the handout (mean 29.6 versus 26.5, p =0.001), particularly with regard to the package enhancing their learning ( p =0.023), being an effective way to learn ( p =0.005), providing practice and feedback ( p p =0.027), user friendly ( p =0.02) and providing learning enjoyment ( p =0.022). Conclusion It is essential that nurses are educated and supported to become, and remain, confident and competent in performing drug calculations. This study found the e-drug calculations package, based on Cognitive Load Theory, to be significantly more effective than a handout in improving students' drug calculation ability and self-efficacy, with students who used the package being significantly more satisfied with its use than students who used the handout. This package could particularly be useful for the continuing professional development of any healthcare professional involved in drug calculations.

Background and aims: CD8 T cells are central to the control of hepatitis C virus (HCV) although the key features of a successful CD8 T cell response remain to be defined. In a cohort of Irish women infected by a single source, a strong association between viral clearance and the human lecucocyte (HLA)-A*03 allele has been described, and the aim of this study was to define the protective nature of the associated CD8 T cell response. Methods: A sequence-led approach was used to identify HLA-A*03-restricted epitopes. We examine the CD8 T cell response associated with this gene and address the likely mechanism underpinning this protective effect in this special cohort, using viral sequencing, T cell assays and analysis of fitness of viral mutants. Results: A strong 'HLA footprint' in a novel NS3 epitope (TVYHGAGTK) was observed. A lysine (K) to arginine (R) substitution at position 9 (K1088R) was seen in a significant number of A*03-positive patients (9/12) compared with the control group (1/33, p=0.0003). Threonine (T) was also substituted with alanine (A) at position 8 (T1087A) more frequently in A*03-positive patients (6/12) compared with controls (2/33, p=0.01), and the double substitution of TK to AR was also observed predominantly in HLA-A*03- positive patients (p=0.004). Epitope-specific CD8 T cell responses were observed in 60% of patients three decades after exposure and the mutants selected in vivo impacted on recognition in vitro. Using HCV replicons matched to the viral sequences, viral fitness was found to be markedly reduced by the K1088R substitution but restored by the second substitution T1087A. Conclusions: It is proposed that at least part of the protective effect of HLA-A*03 results from targeting of this key epitope in a functional site: the requirement for two mutations to balance fitness and escape provides an initial host advantage. This study highlights the potential protective impact of common HLA-A alleles against persistent viruses, with important implications for HCV vaccine studies.

In the version of this article initially published, the PDB code associated with the study was given as 6F2E but should have been 6F2D in Table 1 and the data availability statement. The error has been corrected in the HTML and PDF versions of the article.

Title. Patient safety: numerical skills and drug calculation abilities of nursing students and Registered Nurses. Aim. This paper is a report of a correlational study of the relations of age, status, experience and drug calculation ability to numerical ability of nursing students and Registered Nurses. Background. Competent numerical and drug calculation skills are essential for nurses as mistakes can put patients’ lives at risk. Method. A cross-sectional study was carried out in 2006 in one United Kingdom university. Validated numerical and drug calculation tests were given to 229 second year nursing students and 44 Registered Nurses attending a non-medical prescribing programme. Results. The numeracy test was failed by 55% of students and 45% of Registered Nurses, while 92% of students and 89% of nurses failed the drug calculation test. Independent of status or experience, older participants (‡35 years) were statistically significantly more able to perform numerical calculations. There was no statistically significant difference between nursing students and Registered Nurses in their overall drug calculation ability, but nurses were statistically significantly more able than students to perform basic numerical calculations and calculations for solids, oral liquids and injections. Both nursing students and Registered Nurses were statistically significantly more able to perform calculations for solids, liquid oral and injections than calculations for drug percentages, drip and infusion rates. Conclusion. To prevent deskilling, Registered Nurses should continue to practise and refresh all the different types of drug calculations as often as possible with regular (self)-testing of their ability. Time should be set aside in curricula for nursing students to learn how to perform basic numerical and drug calculations. This learning should be reinforced through regular practice and assessment.

Type Three Secretion Systems (T3SSs) are essential virulence determinants of many Gram-negative bacteria. The T3SS is an injection device that can transfer bacterial virulence proteins directly into host cells. The apparatus is made up of a basal body that spans both bacterial membranes and an extracellular needle that possesses a channel that is thought to act as a conduit for protein secretion. Contact with a host-cell membrane triggers the insertion of a pore into the target membrane, and effectors are translocated through this pore into the host cell. To assemble a functional T3SS, specific substrates must be targeted to the apparatus in the correct order. Recently, there have been many developments in our structural and functional understanding of the proteins involved in the regulation of secretion. Here we review the current understanding of protein components of the system thought to be involved in switching between different stages of secretion.

SoxB is an essential component of the bacterial Sox sulfur oxidation pathway. SoxB contains a di-manganese(II) site and is proposed to catalyze the release of sulfate from a protein-bound cysteine S-thiosulfonate. A direct assay for SoxB activity is described. The structure of recombinant Thermus thermophilus SoxB was determined by x-ray crystallography to a resolution of 1.5 A. Structures were also determined for SoxB in complex with the substrate analogue thiosulfate and in complex with the product sulfate. A mechanistic model for SoxB is proposed based on these structures.

Gram-negative bacteria use type III secretion systems (T3SSs) to pass virulence factors into host cells, making them potential therapeutic targets to combat bacterial infection. A new EM study of the needle complex from the Shigella T3SS reveals 12-fold symmetry throughout and suggests interactions important for self-assembly and complex stability. Type III secretion systems (T3SSs) mediate bacterial protein translocation into eukaryotic cells, a process essential for virulence of many Gram-negative pathogens. They are composed of a cytoplasmic secretion machinery and a base that bridges both bacterial membranes, into which a hollow, external needle is embedded. When isolated, the latter two parts are termed the 'needle complex'. An incomplete understanding of the structure of the needle complex has hampered studies of T3SS function. To estimate the stoichiometry of its components, we measured the mass of its subdomains by scanning transmission electron microscopy (STEM). We determined subunit symmetries by analysis of top and side views within negatively stained samples in low-dose transmission electron microscopy (TEM). Application of 12-fold symmetry allowed generation of a 21–25-A resolution, three-dimensional reconstruction of the needle complex base, revealing many new features and permitting tentative docking of the crystal structure of EscJ, an inner membrane component.

Background: Students on health and social care degree programmes spend 50% of their time on practice placements. Because of the diversity of settings and the need to evidence their work, it is vital to understand the information and resource needs of placement students. Objectives: The aim of this investigation was to understand the needs of placement students in terms of accessing resources whilst they are in the field in order to inform a guide to meet these needs. Methods: Focus groups were conducted with students on midwifery, social work and post-registration health professions degree programmes on three different sites across the region. Data were analysed using Thematic Content Analysis. Results: Three themes emerged from the data: inequality, user education needs and students’ solutions and strategies. Conclusions: It is essential to speak to placement students in order to understand their needs in terms of accessing and using library resources. The timing and content of information skills training is key to meeting student needs while on placement.

The Notch receptor and its ligands are key components in a core metazoan signaling pathway that regulates the spatial patterning, timing and outcome of many cell-fate decisions. Ligands contain a disulfide-rich Delta/Serrate/LAG-2 (DSL) domain required for Notch trans-activation or cis-inhibition. Here we report the X-ray structure of a receptor binding region of a Notch ligand, the DSL-EGF3 domains of human Jagged-1 (J-1(DSL-EGF3)). The structure reveals a highly conserved face of the DSL domain, and we show, by functional analysis of Drosophila melanogster ligand mutants, that this surface is required for both cis- and trans-regulatory interactions with Notch. We also identify, using NMR, a surface of Notch-1 involved in J-1(DSL-EGF3) binding. Our data imply that cis- and trans-regulation may occur through the formation of structurally distinct complexes that, unexpectedly, involve the same surfaces on both ligand and receptor.

The purpose of the study was to report on the changing sources of support structures utilised by pre‐service teachers during a series of school experiences (SEs). A sample of pre‐service teachers was interviewed after their final SE. These students were in their last year of a four‐year Bachelor of Education degree at a college in southern England. The interviews were semi‐structured and focused on categories that originated from previous research. Sources of support were both formal (college tutors and teacher tutors) and informal (other pre‐service teachers, host families and other teachers). It appeared that the respondents moved from formal to informal sources of support as they progressed through the series of SEs. They particularly valued immediate professional support and advice from their teacher tutors and also the social support of their pre‐service and teacher colleagues. This supports the view that learning to teach is a constructivist activity where novitiates move from peripheral participati...

The pathogenic bacterium Shigella flexneri uses a type III secretion system to inject virulence factors from the bacterial cytosol directly into host cells. The machinery that identifies secretion substrates and controls the export of extracellular components and effector proteins consists of several inner-membrane and cytoplasmic proteins. One of the inner membrane components, Spa40, belongs to a family of proteins proposed to regulate the switching of substrate specificity of the export apparatus. We show that Spa40 is cleaved within the strictly conserved amino acid sequence NPTH and substitution of the proposed autocatalytic residue abolishes cleavage. Here we also report the crystal structure of the cytoplasmic complex Spa40(C) and compare it with the recent structures of the homologues from Escherichia coli and Salmonella typhimurium. These structures reveal the tight association of the cleaved fragments and show that the conserved NPTH sequence lies on a loop which, when cleaved, swings away from the catalytic N257 residue, resulting in different surface features in this region. This structural rearrangement suggests a mechanism by which non-cleaving forms of these proteins interfere with correct substrate switching of the apparatus.

The concept of victim responsibility has assumed a central place within psychological research into perceptions of rape. Research repeatedly reports that victims may experience secondary victimization and perpetrators may receive light sentences or even be absolved of the crime. Despite new policies and practices in the UK in respect of rape crimes, attrition rates remain extremely high. This article examines victim responsibility in the talk of convicted sex o fenders and those who work with them. Twenty-three interviews were conducted with professionals and paraprofessionals who work with sex o fenders. The taped therapy sessions of a prison treatment group were the source of perpetrator talk. Discourse analysis identified the existence of two discourses; the discourse of desire and the discourse of commonsense. Separately and together, these discourses served to attribute some responsibility to the victim and to conceptualize rape as sex.

CD97, the archetypal member of the EGF-TM7 protein family, is constitutively expressed on granulocytes and monocytes and rapidly up-regulated on T and B cells following activation. The key isoform of CD97 expressed on leukocytes binds the complement regulatory protein CD55 (also termed decay-accelerating factor). CD97 has been shown recently to mediate co-stimulation of T cells via CD55. Here, we demonstrate that blocking the interaction between CD55 on monocytes and CD97 on T cells leads to inhibition of proliferation and interferon-gamma secretion. This implies that bidirectional interactions between CD97 and CD55 are involved in T cell regulation. Structural studies presented here reveal the molecular basis for this activity. We have solved the structure of EMR2, a very close homolog of CD97, using x-ray crystallography. NMR-based chemical shift mapping of the EMR2-CD55 interaction has allowed us to generate a model for the CD97-CD55 complex. The structure of the complex reveals that the T cell and complement regulatory activities of CD55 occur on opposite faces of the molecule. This suggests that CD55 might simultaneously regulate both the innate and adaptive immune responses, and we have shown that CD55 can still regulate complement when bound to CD97.

Bacteria expressing type III secretion systems (T3SS) have been responsible for the deaths of millions worldwide, acting as key virulence elements in diseases ranging from plague to typhoid fever. The T3SS is composed of a basal body, which traverses both bacterial membranes, and an external needle through which effector proteins are secreted. We report multiple crystal structures of two proteins that sit at the tip of the needle and are essential for virulence; IpaD from Shigella flexneri and BipD from Burkholderia pseudomallei. The structures reveal that the N-terminal domains of the molecules are intra-molecular chaperones that prevent premature oligomerization, as well as sharing structural homology with proteins involved in eukaryotic actin rearrangement. Crystal packing has allowed us to construct a model for the tip complex that is supported by mutations designed using the structure.

Background Health profession students develop practical skills whilst integrating theory with practice in a real world environment as an important component of their training. Research in the area of practice placements has identified challenges and barriers to the delivery of effective placement learning. However, there has been little research in podiatry and the question of which factors impact upon clinical educators’ capacity to engage with the role remains an under-researched area. This paper presents the second phase of an action research project designed to determine the factors that impact upon clinical educators’ capacity to engage with the mentorship role. Methods An online survey was developed and podiatry clinical educators recruited through National Health Service (NHS) Trusts. The survey included socio-demographic items, and questions relating to the factors identified as possible variables influencing clinical educator capacity; the latter was assessed using the ‘Clinical Educator Capacity to Engage’ scale (CECE). Descriptive statistics were used to explore demographic data whilst the relationship between the CECE and socio-demographic factors were examined using inferential statistics in relation to academic profile, career profile and organisation of the placement. Results The survey response rate was 42 % (n = 66). Multiple linear regression identified four independent variables which explain a significant proportion of the variability of the dependent variable, ‘capacity to engage with clinical education’, with an adjusted R2 of 0.428. The four variables were: protected mentorship time, clinical educator relationship with university, sign-off responsibility, and volunteer status. Conclusion The identification of factors that impact upon clinical educators’ capacity to engage in mentoring of students has relevance for strategic planning and policy-making with the emphasis upon capacity-building at an individual level, so that the key attitudes and characteristics that are linked with good clinical supervision are preserved.

Highly polymorphic major histocompatibility complex (MHC) molecules are at the heart of adaptive immune responses, playing crucial roles in many kinds of disease and in vaccination. We report that breadth of peptide presentation and level of cell surface expression of class I molecules are inversely correlated in both chickens and humans. This relationship correlates with protective responses against infectious pathogens including Marek's disease virus leading to lethal tumours in chickens and human immunodeficiency virus infection progressing to AIDS in humans. We propose that differences in peptide binding repertoire define two groups of MHC class I molecules strategically evolved as generalists and specialists for different modes of pathogen resistance. We suggest that differences in cell surface expression level ensure the development of optimal peripheral T cell responses. The inverse relationship of peptide repertoire and expression is evidently a fundamental property of MHC molecules, with ramifications extending beyond immunology and medicine to evolutionary biology and conservation. DOI: http://dx.doi.org/10.7554/eLife.05345.001, eLife digest Our immune system has the remarkable ability to recognize and destroy damaged cells or invading microbes while leaving the healthy cells in the body alone. Groups of proteins called ‘MHC class I molecules’ play important roles in defence against invading microbes. If a cell becomes infected with a virus or a bacterium, these molecules can recognize and bind to fragments of foreign or unusual proteins inside the cell, and display them on the surface of the cell. This allows immune cells to identify and kill the infected cells. Cells produce many different MHC class I molecules that are able to bind to different protein fragments. Some MHC molecules can bind to a wider variety of protein fragments than others, and the number of these molecules present on the cell surface can also vary between individuals. Researchers have noticed that individuals with particular MHC molecules tend to be more or less resistant to particular diseases. For instance, individuals with certain MHC molecules tend to take longer to develop AIDS if they become infected with HIV. However, it is not clear how either the variety of protein fragments bound or the numbers of MHC class I molecules on the surface of cells could alter the immune response. Here, Chappell, Meziane et al. studied MHC class I molecules in chickens and humans. The experiments reveal that the MHC class I molecules that can bind to a larger variety of protein fragments (so-called ‘generalists’) are present in lower numbers on the surface of cells than molecules that can bind to a smaller variety of fragments (so-called ‘specialists’). Furthermore, generalist MHC molecules were found to provide resistance to Marek's disease in chickens—which causes paralysis—but some specialists slowed the progression of HIV infections into AIDS in humans. Chappell, Meziane et al. propose that these two types of MHC class I molecules evolved to perform different roles in immune responses. This is a new way of looking at the role of MHC molecules in fighting disease, and the next challenge is to explore the implications for medicine and evolutionary biology. DOI: http://dx.doi.org/10.7554/eLife.05345.002

BackgroundExisting research identified substantial gaps between NHS mental health services and the criminal justice system for individuals with enduring moderate to severe mental health needs (EMHN). A pilot study in Cornwall echoed these findings, identifying deficiencies in provision at the interface of police and mental health services.AimTo explore the interagency management of individuals with EMHN as they come into contact with the police.DesignA mixed-methods approach within a community psychology framework to enhance the implementation of findings. Stage 1: policy review and clinical audit to identify a sample of mental health service users who were in contact with the police. Stage 2: case-linkage study of 80 service user journeys through services at the time of three types of police contact (Section 136 detention; arrest for criminal offence and contact that did not result in detention); and a health economics component including analysis of the actual cost of 55 service user journeys and enhanced service scenarios. Stage 3: local stakeholder consultation to validate and contextualise case-linkage findings, including a national event.SettingThe research site was the county of Cornwall within the organisational contexts of Cornwall Partnership NHS Foundation Trust and Devon & Cornwall Police.SampleProportionate stratified random sampling identified a sample of 80 cases examined in the case-linkage study from the 538 linked cases identified by the clinical audit.Data sourcesCase-linkage and health economics data involved individuals’ police and mental health records; stakeholder consultation data involved focus groups and interviews.ResultsOf the sample of 80 cases examined, 23 individuals had been detained under Section 136 of the Mental Health Act (1983: Great Britain.Mental Health Act 1983.Chapter 20. London: The Stationery Office; 1983) (accounting for 32 detentions), 52 had been detained in custody on suspicion of an offence (accounting for 126 arrests) and 15 had non-detention contact with the police. Findings showed that where police were aware of mental health needs and individuals were on caseload of a Mental Health Team, there was increased interaction and enhanced outcomes for service users and organisations. The health economics scenario modelling suggests that enhancing services has minimal effects on individual level costs compared with current practice.ConclusionsThe research revealed discrepancy in police and mental health professionals’ assessment of risk and interpretation of protocol and highlighted the need for joint interagency protocols and training to improve information sharing between agencies to enhance the management of individuals with enduring moderate to severe mental health needs.FundingThe National Institute for Health Research Health Services and Delivery Research programme.

The attrition of rape cases from the criminal justice system (CJS) remains high and there is a paucity of research in relation to marginalized groups. Sex workers (SWs) are vulnerable to sexual violence due to the nature of their work. They are also unlikely to report such violence to police for a range of reasons. Two stages of research sought to describe the victim, perpetrator, and offense characteristics of SW rape and to examine the attrition of these cases. All rapes and attempted rapes ( N = 1,146) reported to police in a large city in the South West of England over a 21-year period were examined; 67 cases involved SWs. Data were extracted from police files in line with the variables of interest. Secondary analysis of the total number of SW rapes ( n = 67) resulted in a profile of these cases. A matched pairs study revealed significant differences in victim, perpetrator, and assault characteristics between SW ( n = 62) and non-sex-worker (NSW) samples ( n = 62). Although no significant difference was found in terms of attrition from the CJS, SW cases were observed to secure more convictions for rape than NSW cases. The implications of the findings for practice and future research are discussed.

While a vast literature exists on students and their learning, work on lecturers and their teaching continues to lag some way behind. This paper explores the notion that the complexity of Higher Education (HE) today significantly impacts upon what goes on in the classroom through a two-tiered study. Semi-structured interviews were conducted to explore lecturers’ perceptions and experiences of teaching a specific module. Interviewees raised issues pertaining to the wider departmental, institutional and socio-political context. Consequently, focus groups were run with key people in the University to explore their perceptions of teaching and learning within the current HE climate. The findings suggest that lecturers perceive numerous external factors to impinge upon their teaching and attempt to militate against these in various ways in order to achieve ongoing enhancement of learning for students.

A polymorphism in complement factor H has recently been associated with age-related macular degeneration (AMD), the leading cause of blindness in the elderly. A histidine rather than a tyrosine at residue position 384 in the mature protein increases the risk of AMD. Here, using a recombinant construct, we show that amino acid 384 is adjacent to a heparin-binding site in CCP7 of factor H and demonstrate that the allotypic variants differentially recognize heparin. This functional alteration may affect binding of factor H to polyanionic patterns on host surfaces, potentially influencing complement activation, immune complex clearance, and inflammation in the macula of AMD patients.

Many enteroviruses bind to the complement control protein decay-accelerating factor (DAF) to facilitate cell entry. We present here a structure for echovirus (EV) type 12 bound to DAF using cryo-negative stain transmission electron microscopy and three-dimensional image reconstruction to 16-A resolution, which we interpreted using the atomic structures of EV11 and DAF. DAF binds to a hypervariable region of the capsid close to the 2-fold symmetry axes in an interaction that involves mostly the short consensus repeat 3 domain of DAF and the capsid protein VP2. A bulge in the density for the short consensus repeat 3 domain suggests that a loop at residues 174-180 rearranges to prevent steric collision between closely packed molecules at the 2-fold symmetry axes. Detailed analysis of receptor interactions between a variety of echoviruses and DAF using surface plasmon resonance and comparison of this structure (and our previous work; Bhella, D., Goodfellow, I. G., Roversi, P., Pettigrew, D., Chaudhry, Y., Evans, D. J., and Lea, S. M. (2004) J. Biol. Chem. 279, 8325-8332) with reconstructions published for EV7 bound to DAF support major differences in receptor recognition among these viruses. However, comparison of the electron density for the two virus.receptor complexes (rather than comparisons of the pseudo-atomic models derived from fitting the coordinates into these densities) suggests that the dramatic differences in interaction affinities/specificities may arise from relatively subtle structural differences rather than from large-scale repositioning of the receptor with respect to the virus surface.

The research project, upon which this article is based, conceptualizes the act of graffiti in Bakhtinian terms as a ‘heteroglot’ tangible ‘utterance’: one that is uniquely visual, lexical, and time, place and space specific. The project set out to locate and examine ‘racist’ graffiti; specifically graffiti motivated or prompted by the presence of refugees or ‘asylum seekers’. Despite media reports suggesting that such graffiti was widespread, it proved almost impossible to find. Drawing upon a case study carried out in Sighthill Glasgow, the project was re-focused in order to explain the paucity of such graffiti. In so doing, alternate and clandestine forms of ‘racist’ graffiti became apparent. Inextricably linked to a ‘local code’ known and understood by residents, ‘asylum seekers’ and the local authority — who have responsibility for (re)defining and removing ‘racist’ graffiti — the social, ideological and institutional implications raised are particularly disturbing.

This paper addresses epistemological and methodological issues that surfaced for the authors in a visual research project. Engaging with visual discourse necessitated the authors' interrogation of their own take on issues associated with text and context and the role of reflexivity in the research process. This reflection led us to ruminate still further about the insights that visual discourse could have for qualitative data in general. Thus, the paper first considers the validity of visual data before moving on to address issues of text/context and reflexivity through reference to our work with racist graffiti, in particular, that aimed at people seeking asylum in the UK. In conclusion, the paper argues that there is much to learn from engaging with visual discourse, in terms of understanding social phenomena as well as the process of doing research.

The idea of citizenship dates back to classical antiquity. It was originally concerned to address legitimacy of occupancy in the public sphere. Our empirical study contributes to the project of developing a social psychology of the citizen by focusing on the dynamics of such membership, specifically rights and identities. The authors briefly describe a number of existing psychological models of the citizen. Drawing on the main theoretical principles of discursive psychology, rather than asking, 'who is the citizen?' in terms of mental states, we suggest a shift in focus to the more social question, 'how do people claim citizenship and to what ends?'. We present an analysis of private letters of complaint that formed part of a larger mixed data set used in a recent research programme centred on disputes over Britain's newer travellers' rights of settlement. Specifically our analysis demonstrates how some of the letter writers generate a basis for claims-making by making relevant a citizenship/ governance alignment of identities. We also demonstrate how the entitlements associated with the category citizen are built up and action-oriented rather than flowing from the (unproblematic) assumption of citizenship. Finally we discuss how citizenship can be used for the purposes of inclusion and exclusion.

A cellular receptor for the haemagglutinating enteroviruses (HEV), and the protein that mediates haemagglutination, is the membrane complement regulatory protein decay accelerating factor (DAF; CD55). Although primate DAF is highly conserved, significant differences exist to enable cell lines derived from primates to be utilized for the characterization of the DAF binding phenotype of human enteroviruses. Thus, several distinct DAF-binding phenotypes of a selection of HEVs (viz. coxsackievirus A21 and echoviruses 6, 7, 11-13, 29) were identified from binding and infection assays using a panel of primate cells derived from human, orang-utan, African Green monkey and baboon tissues. These studies complement our recent determination of the crystal structure of SCR(34) of human DAF [Williams, P., Chaudhry, Y., Goodfellow, I. G., Billington, J., Powell, R., Spiller, O. B., Evans, D. J. and Lea, S. (2003). J Biol Chem 278, 10691-10696] and have enabled us to better map the regions of DAF with which enteroviruses interact and, in certain cases, predict specific virus-receptor contacts.

The leader RNA sequence of human immunodeficiency virus type 1 (HIV-1) consists of a complex series of stem loop structures that are critical for viral replication. Three-dimensional structural analysis by NMR of one of these structures, the SL1 stem loop of the packaging signal region, revealed a highly conserved purine rich loop with a structure nearly identical to the Rev-binding loop of the Rev response element. Using band-shift assays, surface plasmon resonance, and further NMR analysis, we demonstrate that this loop binds Rev. HIV-1 appears to have a second Rev-binding site close to the major splice donor site that may have an additional role in the viral life cycle.

If education is to be truly student-centred, students should be consulted about the process of learning and teaching. Moreover, within the current higher education climate, it is imperative that institutions move from an 'inside out' approach, where those on the inside 'know' what is best, to an 'outside in' approach where customers' expectations are researched and serviced. The research reported here investigated higher education students' perceptions of and attitudes to student-centred learning. Two studies were conducted, employing the complementary methods of qualitative and quantitative data collection and analysis. The first study involved focus groups while the second involved an Internet questionnaire. Results showed that students generally held very positive views of student-centred learning. However, they were unsure as to whether current resources were adequate to support the effective implementation and maintenance of such an approach. Implications of these findings are discussed with respect ...

A succession of well-publicized incidents in Britain, and elsewhere, has highlighted the dilemma of refugees and seekers of asylum. A number of desperate human tragedies allied to some very dubious institutional practices and decisions have been a cause for concern. Drawing upon that vast corpus of information we call `common knowledge', together with other more exclusive sources of knowledge, British national newspapers and their readers, among others, are involved in the social construction of asylum-seekers. Ideas of citizenship, identity and Nation-hood are employed within a variety of discursive and rhetorical strategies that form part of an `elite' discourse, one that contributes to a `new Apartheid'. This article presents a discursive and rhetorical analysis of letters written to British national newspapers by members of the public. Asylum-seekers find themselves [re]positioned and contrasted with a variety of other social groups in such a way as to justify disregarding some of the central tenets of British democracy. Dissenting voices and a `counter' discourse are evident although very much a minority. It is argued that applied discursive work is necessary to bolster resistance and deconstruct the `new Apartheid'.

This study sought to develop a profile of rape cases within a Constabulary in the South West of England, and identity factors associated with attrition. All cases of rape or attempted rape of a female or male over the age of 16 from 1996 to 2000 were identified. Quantitative and qualitative data on 379 cases was collected using the CIS and questionnaires sent to the relevant Chief Investigating Officer. The profile of attrition differed in several respects from previous research. Analysis of the extensive written comments provided by the officers afforded insight into the police perspective on rape. The findings are discussed with reference to future research and practice.

Theories of sex offending have for several years relied upon the notion of cognitive distortions as an important cause of sexual offending. In this study we critique this notion and suggest that the sort of phenomenon addressed by cognitive distortions is better understood by adopting a discursive psychology approach. In this approach, talk is regarded as occasioned and action oriented. Thus 'cognitive distortions' are conceptualized as something people do rather than something that people have. Sessions from a prison-based sex offender treatment programme were taped and transcribed. A discursive psychology analysis was conducted on those sessions relating to offenders' first accounts of their offences. Our analysis suggests that offenders utilize a particular narrative organization to manage their blame and responsibility for the offence. This organization is based on a first part which is oriented to quotidian precursors to the offence and an immediately following second which is oriented to a sudden shift in the definition of the situation. The implications of this analysis are discussed, in relation to the status of cognitive distortions and treatment.

Gram-negative bacteria commonly interact with animal and plant hosts using type III secretion systems (TTSSs) for translocation of proteins into eukaryotic cells during infection. 10 of the 25 TTSS-encoding genes are homologous to components of the bacterial flagellar basal body, which the TTSS needle complex morphologically resembles. This indicates a common ancestry, although no TTSS sequence homologues for the genes encoding the flagellum are found. We here present an approximately 16-A structure of the central component, the needle, of the TTSS. Although the needle subunit is significantly smaller and shares no sequence homology with the flagellar hook and filament, it shares a common helical architecture ( approximately 5.6 subunits/turn, 24-A helical pitch). This common architecture implies that there will be further mechanistic analogies in the functioning of these two bacterial systems.