Optimizing the Protection of Cattle against Escherichia coli O157:H7 Colonization through Immunization with Different Combinations of H7 Flagellin,Tir, Intimin-531 or EspA

Enterohemorrhagic Escherichia coli (EHEC) are important human pathogens, causing hemorrhagic colitis and hemolytic uraemic syndrome in humans. E. coli O157:H7 is the most common serotype associated with EHEC infections worldwide, although other non-O157 serotypes cause life-threatening infections. Cattle are a main reservoir of EHEC and intervention strategies aimed at limiting EHEC excretion from cattle are predicted to lower the risk of human infection. We have previously shown that immunization of calves with recombinant versions of the type III secretion system (T3SS)-associated proteins EspA, intimin and Tir from EHEC O157:H7 significantly reduced shedding of EHEC O157 from experimentally-colonized calves, and that protection could be augmented by the addition of H7 flagellin to the vaccine formulation. The main aim of the present study was to optimize our current EHEC O157 subunit vaccine formulations by identifying the key combinations of these antigens required for protection. A secondary aim was to determine if vaccine-induced antibody responses exhibited cross-reactive potential with antigens from other EHEC serotypes. Immunization with EspA, intimin and Tir resulted in a reduction in mean EHEC O157 shedding following challenge, but not the mean proportion of calves colonized. Removal of Tir resulted in more prolonged shedding compared with all other groups, whereas replacement of Tir with H7 flagellin resulted in the highest levels of protection, both in terms of reducing both mean EHEC O157 shedding and the proportion of colonized calves. Immunization of calves with recombinant EHEC O157 EspA, intimin and Tir resulted in the generation of antibodies capable of cross-reacting with antigens from non-O157 EHEC serotypes, suggesting that immunization with these antigens may provide a degree of cross-protection against other EHEC serotypes. Further studies are now required to test the efficacy of these vaccines in the field, and to formally test the cross-protective potential of the vaccines against other non-O157 EHEC.     

Cytokines in the host response to Candida vaginitis: Identifying a role for non-classical immune mediators, S100 alarmins

Vulvovaginal candidiasis (VVC), caused by Candida albicans, affects a significant number of women during their reproductive years. More than two decades of research have been focused on the mechanisms associated with susceptibility or resistance to symptomatic infection. Adaptive immunity by Th1-type CD4(+) T cells and downstream cytokine responses are considered the predominant host defense mechanisms against mucosal Candida infections. However, numerous clinical and animal studies have indicated no or limited protective role of cells and cytokines of the Th1 or Th2 lineage against vaginal infection. The role for Th17 is only now begun to be investigated in-depth for VVC with results already showing significant controversy. On the other hand, a clinical live-challenge study and an established animal model have shown that a symptomatic condition is intimately associated with the vaginal infiltration of polymorphonuclear leukocytes (PMNs) but with no effect on vaginal fungal burden. Subsequent studies identified S100A8 and S100A9 alarmins as key chemotactic mediators of the acute PMN response. These chemotactic danger signals appear to be secreted by vaginal epithelial cells upon interaction and early adherence of Candida. Thus, instead of a putative immunodeficiency against Candida involving classical immune cells and cytokines of the adaptive response, the pathological inflammation in VVC is now considered a consequence of a non-productive innate response initiated by non-classical immune mediators.     

Flexible tethering of primase and DNA Pol α in the eukaryotic primosome

The Pol α/primase complex or primosome is the primase/polymerase complex that initiates nucleic acid synthesis during eukaryotic replication. Within the primosome, the primase synthesizes short RNA primers that undergo limited extension by Pol α. The resulting RNA–DNA primers are utilized by Pol δ and Pol ε for processive elongation on the lagging and leading strands, respectively. Despite its importance, the mechanism of RNA–DNA primer synthesis remains poorly understood. Here, we describe a structural model of the yeast primosome based on electron microscopy and functional studies. The 3D architecture of the primosome reveals an asymmetric, dumbbell-shaped particle. The catalytic centers of primase and Pol α reside in separate lobes of high relative mobility. The flexible tethering of the primosome lobes increases the efficiency of primer transfer between primase and Pol α. The physical organization of the primosome suggests that a concerted mechanism of primer hand-off between primase and Pol α would involve coordinated movements of the primosome lobes. The first three-dimensional map of the eukaryotic primosome at 25 Å resolution provides an essential structural template for understanding initiation of eukaryotic replication.     

“It could just be an additional test couldn't it?” 1 Genetic testing for susceptibility to aggression and violence

Much of the current genetic research into aggressive and violent behavior focuses on young people and might appear to offer the hope of targeted prediction and intervention. In the UK data are collected on children from various agencies and collated to produce “at risk of offending” identities used to justify intervention. Information from behavioral genetic tests could conceivably be included. Regulatory frameworks for collecting, storing and using information from DNA samples differ between the health service and the police particularly in the need for consent and the treatment of children. This paper draws on discussions with professionals involved with “problem” young people to consider their views on the utility of genetic research for tackling violent/aggressive behavior and the impact an identification of genetic susceptibility might have on their clients.     

ERG2 and ERG24 Are Required for Normal Vacuolar Physiology as Well as Candida albicans Pathogenicity in a Murine Model of Disseminated but Not Vaginal Candidiasis

Several important classes of antifungal agents, including the azoles, act by blocking ergosterol biosynthesis. It was recently reported that the azoles cause massive disruption of the fungal vacuole in the prevalent human pathogen Candida albicans. This is significant because normal vacuolar function is required to support C. albicans pathogenicity. This study examined the impact of the morpholine antifungals, which inhibit later steps of ergosterol biosynthesis, on C. albicans vacuolar integrity. It was found that overexpression of either the ERG2 or ERG24 gene, encoding C-8 sterol isomerase or C-14 sterol reductase, respectively, suppressed C. albicans sensitivity to the morpholines. In addition, both erg2Δ/Δ and erg24Δ/Δ mutants were hypersensitive to the morpholines. These data are consistent with the antifungal activity of the morpholines depending upon the simultaneous inhibition of both Erg2p and Erg24p. The vacuoles within both erg2Δ/Δ and erg24Δ/Δ C. albicans strains exhibited an aberrant morphology and accumulated large quantities of the weak base quinacrine, indicating enhanced vacuolar acidification compared with that of control strains. Both erg mutants exhibited significant defects in polarized hyphal growth and were avirulent in a mouse model of disseminated candidiasis. Surprisingly, in a mouse model of vaginal candidiasis, both mutants colonized mice at high levels and induced a pathogenic response similar to that with the controls. Thus, while targeting Erg2p or Erg24p alone could provide a potentially efficacious therapy for disseminated candidiasis, it may not be an effective strategy to treat vaginal infections. The potential value of drugs targeting these enzymes as adjunctive therapies is discussed.     

Synthesis and structural characterisation of a novel polynuclear copper ribbon-like network. A study of its magnetic properties between 4 and 300 K

A new route to {Cu₂(κ¹-pyNH₂)₂(μ-OMe)₂Cl₂}_n (pyNH₂ = 2-aminopyridine) (3) is reported. Structural characterisation reveals the presence of methoxide and chloride bridging units within the complex which support close copper-copper bonding interactions resulting in interesting magnetic properties. The variable-temperature (4-300 K) magnetic susceptibility data of the complex were interpreted with the dimer law using the molecular field approximation. The results obtained indicate a weak antiferromagnetic (zJ′ = −15 cm⁻¹) inter-chain interaction through the chloro-bridge. A relatively strong antiferromagnetic interaction, transmitted through the oxygen-bridge, with an exchange coupling of 2J = −305 cm⁻¹, which dominates the magnetic properties of the title complex.     

How to evaluate and improve the quality and credibility of an outcomes database: validation and feedback study on the UK Cardiac Surgery Experience

ObjectivesTo assess the quality and completeness of a database of clinical outcomes after cardiac surgery and to determine whether a process of validation, monitoring, and feedback could improve the quality of the database.DesignStratified sampling of retrospective data followed by prospective re-sampling of database after intervention of monitoring, validation, and feedback.SettingTen tertiary care cardiac surgery centres in the United Kingdom.InterventionValidation of data derived from a stratified sample of case notes (recording of deaths cross checked with mortuary records), monitoring of completeness and accuracy of data entry, feedback to local data managers and lead surgeons.ResultsThe database was incomplete, with a mean (SE) of 24.96% (0.09%) of essential data elements missing, whereas only 1.18% (0.06%) were missing in the patient records (P<0.0001). Intervention was associated with (a) significantly less missing data (9.33% (0.08%) P<0.0001); (b) marginal improvement in reliability of data and mean (SE) overall centre reliability score (0.53 (0.15) v 0.44 (0.17)); and (c) improved accuracy of assigned Parsonnet risk scores (κ 0.84 v 0.70). Mortality scores (actual minus risk adjusted mortality) for all participating centres fell within two standard deviations of the mean score.ConclusionA short period of independent validation, monitoring, and feedback improved the quality of an outcomes database and improved the process of risk adjustment, but with substantial room for further improvement. Wider application of this approach should increase the credibility of similar databases before their public release.

What is already know in this topic

Release of healthcare outcomes into the public domain has altered referral patterns and has led to improvement in some centres and elimination of othersThe tacit assumption is that such outcomes data are accurate and can be relied on by the public and by healthcare providers to guide improvements

What this study adds

Sampling of a published national cardiac surgery database in England revealed it to be both incomplete and unreliable in its ability to yield accurate, risk adjusted outcomes dataAn independent short process of monitoring, validation, and feedback improved the quality of the databaseSuch databases probably require an ongoing process of monitoring in order to allow data of adequate quality to be generated for the purpose of improving healthcare outcomes     

Risky individuals and the politics of genetic research into aggressiveness and violence

New genetic technologies promise to generate valuable insights into the aetiology of several psychiatric conditions, as well as a wider range of human and animal behaviours. Advances in the neurosciences and the application of new brain imaging techniques offer a way of integrating DNA analysis with studies that are looking at other biological markers of behaviour. While candidate 'genes for' certain conditions, including schizophrenia and bipolar disorders, are said to be 'un-discovered' at a faster rate than they are discovered, many studies are being conducted on personality traits such as aggressiveness and anti-social traits. The clinical applicability and implications of these studies are often discussed within the scientific community. However, little attention has so far been paid to their possible policy implications in relation to criminality management and to Criminal Law itself. Similarly, the related ethical issues arising in the field of crime control, and the tensions between enhancing security for society and protecting civil liberties, are currently under-explored. This paper investigates these ethical issues by focusing on the views of those professionals - including judges, lawyers, probation officers and social workers - who work with individuals 'deemed at risk' of violent and aggressive behaviours. It also discusses and problematizes mainstream rhetoric and arguments around the notion of 'risky individuals'.     

c-Src regulation of fibroblast growth factor-induced proliferation in murine embryonic fibroblasts

Activated fibroblast growth factor receptor 1 (FGFR1) propagates FGF signals through multiple intracellular pathways via intermediates FRS2, PLCgamma, and Ras. Conflicting reports exist concerning the interaction between FGFR1 and Src family kinases. To address the role of c-Src in FGFR1 signaling, we compared proliferative responses of murine embryonic fibroblasts (MEF) deficient in c-Src, Yes, and Fyn to MEF expressing either endogenous levels or overexpressing c-Src. MEF with endogenous c-Src had significantly greater FGF-induced DNA synthesis and proliferation than cells lacking or overexpressing c-Src. This was related directly to c-Src expression by analysis of c-Src-deficient cells transfected with and sorted for varying levels of a c-Src expression vector. This suggests an "optimal" quantity of c-Src expression for FGF-induced proliferation. To determine if this was a general phenomenon for growth factor signaling pathways utilizing c-Src, responses to epidermal growth factor (EGF), platelet-derived growth factor (PDGF), and lysophosphatidic acid (LPA) were examined. As for FGF, responses to EGF were clearly inhibited when c-Src was absent or overexpressed. In contrast, varying levels of c-Src had little effect on responses to PDGF or LPA. The data show that mitogenic pathways activated by FGF-1 and EGF are regulated by c-Src protein levels and appear to differ significantly from those activated by PDGF and LPA.     

The protein tyrosine phosphatase SHP-2 regulates interleukin-1-induced ERK activation in fibroblasts

Focal adhesion complexes are actin-rich, cytoskeletal structures that mediate cell adhesion to the substratum and also selectively regulate signal transduction pathways required for interleukin (IL)-1beta signaling to the MAP kinase, ERK. IL-1-induced ERK activation is markedly diminished in fibroblasts deprived of focal adhesions whereas activation of p38 and JNK is unaffected. While IL-1 signaling is known to involve the activity of protein and lipid kinases including MAP kinases, FAK, and PI3K, little is known about the role of phosphatases in the regulation of IL-1 signal generation and attenuation. Here we demonstrate that SHP-2, a protein tyrosine phosphatase present in focal adhesions, modulates IL-1-induced ERK activation and the transient actin stress fiber disorganization that occurs following IL-1 treatment in human gingival fibroblasts. Using a combination of immunoblotting, immunoprecipitation, and immunostaining we show that SHP-2 is present in nascent focal adhesions and undergoes phosphorylation on tyrosine 542 in response to IL-1 stimulation. Blocking anti-SHP-2 antibodies, electoporated into the cytosol of fibroblasts, inhibited IL-1-induced ERK activation, actin filament assembly, and cell contraction, indicating a role for SHP-2 in these processes. In summary, our data indicate that SHP-2, a focal adhesion-associated protein, participates in IL-1-induced ERK activation likely via an adaptor function.