IL-1 Family Cytokines Use Distinct Molecular Mechanisms to Signal through Their Shared Co-receptor.

Within the interleukin 1 (IL-1) cytokine family, IL-1 receptor accessory protein (IL-1RAcP) is the co-receptor for eight receptor-cytokine pairs, including those involving cytokines IL-1ß and IL-33. Unlike IL-1ß, IL-33 does not have a signaling complex that includes both its cognate receptor, ST2, and the shared co-receptor IL-1RAcP, which we now present here. Although the IL-1ß and IL-33 complexes shared structural features and engaged identical molecular surfaces of IL-1RAcP, these cytokines had starkly different strategies for co-receptor engagement and signal activation. Our data suggest that IL-1ß binds to IL-1RI to properly present the cytokine to IL-1RAcP, whereas IL-33 binds to ST2 in order to conformationally constrain the cognate receptor in an IL-1RAcP-receptive state. These findings indicate that members of the IL-1 family of cytokines use distinct molecular mechanisms to signal through their shared co-receptor, and they provide the foundation from which to design new therapies to target IL-33 signaling.

SiteMine: Large-scale binding site similarity searching in protein structure databases.

Drug discovery and design challenges, such as drug repurposing, analyzing protein-ligand and protein-protein complexes, ligand promiscuity studies, or function prediction, can be addressed by protein binding site similarity analysis. Although numerous tools exist, they all have individual strengths and drawbacks with regard to run time, provision of structure superpositions, and applicability to diverse application domains. Here, we introduce SiteMine, an all-in-one database-driven, alignment-providing binding site similarity search tool to tackle the most pressing challenges of binding site comparison. The performance of SiteMine is evaluated on the ProSPECCTs benchmark, showing a promising performance on most of the data sets. The method performs convincingly regarding all quality criteria for reliable binding site comparison, offering a novel state-of-the-art approach for structure-based molecular design based on binding site comparisons. In a SiteMine showcase, we discuss the high structural similarity between cathepsin L and calpain 1 binding sites and give an outlook on the impact of this finding on structure-based drug design. SiteMine is available at https://uhh.de/naomi.

In Situ Observation of C-C Coupling and Step Poisoning During the Growth of Hydrocarbon Chains on Ni(111).

The synthesis of high-value fuels and plastics starting from small hydrocarbon molecules plays a central role in the current transition towards renewable energy. However, the detailed mechanisms driving the growth of hydrocarbon chains remain to a large extent unknown. Here we investigated the formation of hydrocarbon chains resulting from acetylene polymerization on a Ni(111) model catalyst surface. Exploiting X-ray photoelectron spectroscopy up to near-ambient pressures, the intermediate species and reaction products have been identified. Complementary in situ scanning tunneling microscopy observations shed light onto the C-C coupling mechanism. While the step edges of the metal catalyst are commonly assumed to be the active sites for the C-C coupling, we showed that the polymerization occurs instead on the flat terraces of the metallic surface.

Exploiting Cooperative Catalysis for the On-Surface Synthesis of Linear Heteroaromatic Polymers via Selective C-H Activation.

Regiospecific C-H activation is a promising approach to achieve extended polymers with tailored structures. While a recent on-surface synthetic approach has enabled regioselective homocoupling of heteroaromatic molecules, only small oligomers have been achieved. Herein, selective C-H activation for dehydrogenative C-C couplings of hexaazatriphenylene by Scholl reaction is reported for the first time. By combining low-temperature scanning tunneling microscopy (STM) and atomic force microscopy (AFM), we revealed the formation of one-dimensional polymers with a double-chain structure. The details of the growth process are rationalized by density functional theory (DFT) calculations, pointing out a cooperative catalytic action of Na and Ag adatoms in steering the C-H selectivity for the polymerization.

Method for the Manual Analysis of Moiré Structures in STM images.

A method is presented to manually determine the lattice parameters of commensurate hexagonal moiré structures resolved by STM. It solves the problem that lattice parameters of moiré structures usually cannot be determined by inspection of an STM image, so that computer-based analyses are required. The lattice vector of a commensurate moiré structure is a sum of integer multiples both of the two basis vectors of the substrate and of the adsorbed layer. The method extracts the two factors with respect to the adsorbed layer from an analysis of the Fourier transform of an STM image. These two factors are related to the two factors with respect to the substrate layer. Using the cell augmentation method, six possible moiré structures are identified by algebra. When the orientation and lattice constant of the substrate are roughly known, this information is usually sufficient to determine a unique moiré structure and its lattice parameters.

[The association between school tobacco policies and the perceived smoking prevalence of adolescents]. / Der Zusammenhang zwischen schulischer Tabakkontrolle und der wahrgenommenen Raucherprävalenz Jugendlicher.

BACKGROUND: In the German context, there is hardly any quantitative data about the implementation of school tobacco polices that include the perspective of both teachers and students. The aim of the study is to investigate the associations between implemented school tobacco policies and the perceived prevalence of smoking at the level of school staff and adolescents. METHODS: The repeated cross-sectional study (2013 and 2017) is based on pooled responses of 13- to 17-year-old adolescents (N = 2393) and school staff (N = 85) from 25 schools located in the West German metropolitan region of Hanover. In linear regression models, average marginal effects (AMEs) with 95% confidence intervals (CI95%) and robust standard errors for perceived tobacco prevalence are reported separately for school tobacco policies assessed by teachers and students (scale 0-6). All models were controlled for sociodemographic, school-, and smoking-specific covariates. RESULTS: On average, adolescents perceive a smoking prevalence of 30% ([Formula: see text]; s: 24.0) for their school. A comprehensive school tobacco policy is consistently associated with lower school smoking prevalence both from the point of view of teachers (AME: -3.54 CI95% -6.49 to -0.58) and students (AME: -1.69 CI95% -2.52 to -0.86). The number of smoking friends (e.g., "most of them are smokers" +14%: AME: 14.13 CI95% 10.46 to 17.80) and the type of school are the most relevant determinants of a high school smoking prevalence. School types with a nonacademic track report a 15% (AME: 15.03 CI95% 10.13 to 19.93) higher prevalence compared to grammar schools. DISCUSSION: Progressive school tobacco control policies should focus more on school types with nonacademic tracks, certain groups at risk, and those schools that do not strictly enforce school tobacco policies.

Culicoidibacter larvae gen. nov., sp. nov., from the gastrointestinal tract of the biting midge (Culicoides sonorensis) larva, belongs to a novel lineage Culicoidibacteraceae fam. nov., Culicoidibacterales ord. nov. and Culicoidibacteria classis nov. of the phylum Firmicutes.

Strain CS-1T, a novel facultative anaerobic bacterium, was isolated from the larval gastrointestinal tract of the biting midge, Culicoides sonorensis, a vector of the epizootic haemorrhagic disease virus and the bluetongue virus. Cells were Gram-stain-positive, non-motile, non-spore-forming, pleomorphic rods. Optimal growth occurred at pH 7.5 and 37 °C. The G+C content of the genomic DNA was 38.3 mol%, estimated by using HPLC. The dominant cellular fatty acids were C14 : 0 (45.9 %) and C16 : 0 (26.6 %). The polar lipid profile comprised glycolipids, diphosphatidylglycerol, phospholipids and phosphoglycolipids. Respiratory quinones were not detected. Strain CS-1T had very low 16S rRNA gene similarity to members of the phylum Firmicutes: Macrococcus canis KM45013T (85 % similarity) and Turicibacter sanguinis MOL361T (88 % similarity). Phylogenetic analysis based on 16S rRNA, rpoB, gyrB genes, and conserved protein sequences of the whole genome revealed that strain CS-1T was related to members of the classes Bacilli and Erysipelotrichia within the phylum Firmicutes. Furthermore, average nucleotide identity and digital DNA-DNA hybridization analyses of the whole genome revealed very low sequence similarity to species of Bacilli and Erysipelotrichaceae (Macrococcus canis KM45013T and Turicibacter sp. H121). These results indicate that strain CS-1T belongs to the phylum Firmicutes and represents a new species of a novel genus, family, order and class. Based on the phenotypic, chemotaxonomic, phylogenetic and genomic characteristics, we propose the novel taxon Culicoidibacter larvae gen. nov., sp. nov. with the type strain CS-1T (=CCUG 71726T=DSM 106607T) within the hereby new proposed novel family Culicoidibacteraceae fam. nov., new order Culicoidibacaterales ord. nov. and new class Culicoidibacteria classis nov. in the phylum Firmicutes.

Social mobility, accumulation of disadvantages and health. An analysis with retrospective data from the GSOEP (2002-14).

BACKGROUND: Socioeconomic position (SEP) in different life stages is related to health-related quality of life (HRQoL). Yet, research on the relevance of life course processes is scarce. This study aims to analyse the association between accumulation of disadvantages, social mobility and HRQoL. METHODS: Analyses were conducted using population-averaged panel-data models and are based on data from the German Socio-Economic Panel 2002-14, including retrospective biographical information, comprising 25 473 observations from 8666 persons. Intergenerational and intragenerational mobility included the occupational positions in childhood (parental position), first job and middle age. Accumulation of disadvantages was measured using an accumulation index. HRQoL was assessed using the Mental and Physical Component Summary Scores of the SF12v2. RESULTS: Accumulation of disadvantages was the main predictor for the Physical Component Summary in mid-age. Men and women in a stable low SEP or with a steep downward mobility showed the least favourable physical HRQoL. This holds for intergenerational and intragenerational mobility. Mental HRQoL did not seem to be associated with accumulation or social mobility. CONCLUSION: The results show that physical HRQoL is related to social mobility and accumulation of (dis-)advantages. Further research is needed thoroughly analysing this association.

Generation and Stabilization of Small Platinum Clusters Pt12±x Inside a Metal-Organic Framework.

The generation and matrix stabilization of ligand-free, small platinum nanoclusters (NCs) Pt12±x is presented. The metal-organic framework-template approach is based on encapsulating CO-ligated, atom-precise Pt9 Chini clusters [{Pt3(CO)6}3]2- into the zeolitic imidazolate framework ZIF-8. The selective formation of the air-stable inclusion compound [NBu4]2[{Pt3(CO)6}4]@ZIF-8 of defined atomicity Pt12 and with Pt loadings of 1-20 wt % was monitored by UV/vis and IR spectroscopy and was confirmed by high-resolution transmission electron microscopy (HR-TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray photoelectron spectroscopy (XPS), and powder X-ray diffraction (PXRD). Thermally induced decarbonylation at 200 °C yields the composite material Ptn@ZIF-8 with a cluster atomicity n close to 12, irrespective of the Pt loading. The PtNCs retain their size even during annealing at 300 °C for 24 h and during catalytic hydrogenation of 1-hexene at 25 °C in the liquid phase. The Ptn@ZIF-8 material can conveniently be used for storing small PtNCs and their further processing. Removal of the protective ZIF-8 matrix under acidic conditions and transfer of the PtNCs to carbon substrates yields defined aggregation to small Pt nanoparticles (1.14 ± 0.35 nm, HR-TEM), which have previously shown exceptional performance in the electrocatalytic oxygen reduction reaction (ORR).

Direct CD137 costimulation of CD8 T cells promotes retention and innate-like function within nascent atherogenic foci.

Effector CD8 T cells infiltrate atherosclerotic lesions and are correlated with cardiovascular events, but the mechanisms regulating their recruitment and retention are not well understood. CD137 (4-1BB) is a costimulatory receptor induced on immune cells and expressed at sites of human atherosclerotic plaque. Genetic variants associated with decreased CD137 expression correlate with carotid-intimal thickness and its deficiency in animal models attenuates atherosclerosis. These effects have been attributed in part to endothelial responses to low and disturbed flow (LDF), but CD137 also generates robust effector CD8 T cells as a costimulatory signal. Thus, we asked whether CD8 T cell-specific CD137 stimulation contributes to their infiltration, retention, and IFNγ production in early atherogenesis. We tested this through adoptive transfer of CD8 T cells into recipient C57BL/6J mice that were then antigen primed and CD137 costimulated. We analyzed atherogenic LDF vessels in normolipidemic and PCSK9-mediated hyperlipidemic models and utilized a digestion protocol that allowed for lesional T-cell characterization via flow cytometry and in vitro stimulation. We found that CD137 activation, specifically of effector CD8 T cells, triggers their intimal infiltration into LDF vessels and promotes a persistent innate-like proinflammatory program. Residence of CD137+ effector CD8 T cells further promoted infiltration of endogenous CD8 T cells with IFNγ-producing potential, whereas CD137-deficient CD8 T cells exhibited impaired vessel infiltration, minimal IFNγ production, and reduced infiltration of endogenous CD8 T cells. Our studies thus provide novel insight into how CD137 costimulation of effector T cells, independent of plaque-antigen recognition, instigates their retention and promotes innate-like responses from immune infiltrates within atherogenic foci. NEW & NOTEWORTHY Our studies identify CD137 costimulation as a stimulus for effector CD8 T-cell infiltration and persistence within atherogenic foci, regardless of atherosclerotic-antigen recognition. These costimulated effector cells, which are generated in pathological states such as viral infection and autoimmunity, have innate-like proinflammatory programs in circulation and within the atherosclerotic microenvironment, providing mechanistic context for clinical correlations of cardiovascular morbidity with increased CD8 T-cell infiltration and markers of activation in the absence of established antigen specificity.

[Intragenerational Mobility and Subjective Health: Findings of the Socio-Economic Panel (GSOEP) 1992-2012]. / Intragenerationale Mobilität und subjektive Gesundheit ­ Ergebnisse des Sozio-oekonomischen Panels (SOEP) von 1992­2012.

AIM OF THE STUDY: International research suggests that mobility plays an important role in determining health in later life. The aim of this study was to analyze the relationship between intragenerational mobility and subjective health on the basis of data from Germany, taking different periods from 1992 to 2012 into account. DATA AND METHODS: Data is derived from the Socio-economic Panel (GSOEP), taking three time periods into account (1992-1995, 2000-2003 and 2008-2012). Intragenerational mobility was measured by comparing first occupational position and current job. Logistic regressions were used in order to analyze the relationship between health and mobility. RESULTS: Men and women who were downwardly mobile in unemployment or stable low reported the worst health. Up- and downwardly mobile people were located between the stable-up and stable-low groups. The relationship was not affected by origin (East/West Germany). Yet, upward mobility was more common in West Germany and downward mobility was more frequent in East Germany. In general, men and women showed similar patterns. The relationship between intragenerational mobility and health remained stable over time. CONCLUSION: Occupational development showed a strong relationship with health in later life. Especially downward mobility into unemployment or staying in lower positions had strong influence on health. Socio-political measures should be taken to prevent a further divergence of health opportunities.

Optimizing the Size of Platinum Nanoparticles for Enhanced Mass Activity in the Electrochemical Oxygen Reduction Reaction.

High oxygen reduction (ORR) activity has been for many years considered as the key to many energy applications. Herein, by combining theory and experiment we prepare Pt nanoparticles with optimal size for the efficient ORR in proton-exchange-membrane fuel cells. Optimal nanoparticle sizes are predicted near 1, 2, and 3 nm by computational screening. To corroborate our computational results, we have addressed the challenge of approximately 1 nm sized Pt nanoparticle synthesis with a metal-organic framework (MOF) template approach. The electrocatalyst was characterized by HR-TEM, XPS, and its ORR activity was measured using a rotating disk electrode setup. The observed mass activities (0.87±0.14 A mgPt -1 ) are close to the computational prediction (0.99 A mgPt -1 ). We report the highest to date mass activity among pure Pt catalysts for the ORR within similar size range. The specific and mass activities are twice as high as the Tanaka commercial Pt/C catalysis.

Imaging the confined surface oxidation of Ni3Al(111) by in situ high temperature scanning tunneling microscopy.

The initial oxidation of Ni3Al(111) was imaged by in situ scanning tunneling microscopy (STM) at 700-750 K. At 740 K ± 10 K a moiré structure is formed as the major surface phase: high resolution STM data atomically resolve a top hexagonal lattice with a lattice constant of 2.93 ± 0.01 Å aligned or slightly rotated with respect to the substrate. Auger electron spectra acquired from the surface phase identify Al atoms in an oxidic environment together with Ni atoms unaffected by the oxidation of the Ni3Al(111) surface. A special mass balance analysis applied to STM images recorded during formation of the moiré structure allowed to extract the metal content of the surface phase. The moiré phase can be attributed to a single O/Al double layer of α-Al2O3 ontop of the Ni3Al(111) crystal. The surface double layer is laterally expanded by ∼7% with respect to α-Al2O3 and, relating to the next nearest neighbor distance of the substrate of 2.52 Å, it contains 0.73 ML oxygen and 0.49 ML aluminium atoms. The building principle of the surface phase is almost identical to the one of the reported Oi/Ali interface layer of the so called surface oxide, except for its rotational alignment with respect to the substrate as shown in a careful moiré analysis. It could be shown that this thinnest possible surface aluminum oxide layer is formed due to kinetic restrictions: the oxide grows within the first layer of the Ni3Al(111) surface ejecting 0.5 ML surface metal atoms, which are then converted into the surface oxide laterally separated at the ascending step edge of the same terrace. While the formation of the surface oxide is kinetically hindered most likely by the availability of Al adatoms, all rearrangement processes required for the surface oxide formation on each terrace are not rate limiting as identified by in situ STM. Instead, the local oxide growth rather follows the kinetics driven by the adsorption probability of the impinging oxygen molecules and provides the possibility to entirely cover whole Ni3Al(111) surface.

Diverse oligomeric states of CEACAM IgV domains.

Carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) comprise a large family of cell surface adhesion molecules that bind to themselves and other family members to carry out numerous cellular functions, including proliferation, signaling, differentiation, tumor suppression, and survival. They also play diverse and significant roles in immunity and infection. The formation of CEACAM oligomers is caused predominantly by interactions between their N-terminal IgV domains. Although X-ray crystal structures of CEACAM IgV domain homodimers have been described, how CEACAMs form heterodimers or remain monomers is poorly understood. To address this key aspect of CEACAM function, we determined the crystal structures of IgV domains that form a homodimeric CEACAM6 complex, monomeric CEACAM8, and a heterodimeric CEACAM6-CEACAM8 complex. To confirm and quantify these interactions in solution, we used analytical ultracentrifugation to measure the dimerization constants of CEACAM homodimers and isothermal titration calorimetry to determine the thermodynamic parameters and binding affinities of CEACAM heterodimers. We found the CEACAM6-CEACAM8 heterodimeric state to be substantially favored energetically relative to the CEACAM6 homodimer. Our data provide a molecular basis for the adoption of the diverse oligomeric states known to exist for CEACAMs and suggest ways in which CEACAM6 and CEACAM8 regulate the biological functions of one another, as well as of additional CEACAMs with which they interact, both in cis and in trans.

[Intergenerational mobility and health inequalities in East and West Germany : A trend analysis from 1992 to 2012]. / Intergenerationale Mobilität und gesundheitliche Ungleichheiten in Ost- und Westdeutschland : Eine Trendanalyse von 1992 bis 2012.

BACKGROUND: Social mobility processes, i. e. the movement of a person from one social position to another, are central mechanisms for explaining health inequalities. Social differences in health status or behaviour may also change with changes in social status. This article examines the importance of intergenerational mobility, i. e. the rise and fall of social status in relation to parental social position, for subjective health in East and West Germany and whether this relationship has changed over 20 years. MATERIAL AND METHODS: The data basis is the socio-economic panel from 1992-2012. Employees aged between 25 and 59 were taken into account. Different mobility paths were determined by comparing their current occupational positions with those of their parents. For these, prevalence and logistic regression of subjective health were calculated. RESULTS: Those in low occupational positions rated their health more often as being worse in all periods. Upwardly mobile individuals had a lower risk of poorer health (OR 0.72) compared to those who remained in their original position. Persons affected by downward mobility had a similarly worse self-rated health (OR 1.55 or OR 1.86). Significant differences in gender or region of origin (East-West Germany) could not be determined. Education and income contribute to explaining the relationship. CONCLUSION: The results suggest that social advancement has a positive effect on health, whereas social decline is negative - regardless of gender, region of origin or time. It is therefore important to reinforce political efforts aimed at increasing the mobility opportunities of all social groups in a positive sense and thus reducing social inequalities.

Structure and Dynamics of FosA-Mediated Fosfomycin Resistance in Klebsiella pneumoniae and Escherichia coli.

Fosfomycin exhibits broad-spectrum antibacterial activity and is being reevaluated for the treatment of extensively drug-resistant pathogens. Its activity in Gram-negative organisms, however, can be compromised by expression of FosA, a metal-dependent transferase that catalyzes the conjugation of glutathione to fosfomycin, rendering the antibiotic inactive. In this study, we solved the crystal structures of two of the most clinically relevant FosA enzymes: plasmid-encoded FosA3 from Escherichia coli and chromosomally encoded FosA from Klebsiella pneumoniae (FosAKP). The structure, molecular dynamics, catalytic activity, and fosfomycin resistance of FosA3 and FosAKP were also compared to those of FosA from Pseudomonas aeruginosa (FosAPA), for which prior crystal structures exist. E. coli TOP10 transformants expressing FosA3 and FosAKP conferred significantly greater fosfomycin resistance (MIC, >1,024 µg/ml) than those expressing FosAPA (MIC, 16 µg/ml), which could be explained in part by the higher catalytic efficiencies of the FosA3 and FosAKP enzymes. Interestingly, these differences in enzyme activity could not be attributed to structural differences at their active sites. Instead, molecular dynamics simulations and hydrogen-deuterium exchange experiments with FosAKP revealed dynamic interconnectivity between its active sites and a loop structure that extends from the active site of each monomer and traverses the dimer interface. This dimer interface loop is longer and more extended in FosAKP and FosA3 than in FosAPA, and kinetic analyses of FosAKP and FosAPA loop-swapped chimeric enzymes highlighted its importance in FosA activity. Collectively, these data yield novel insights into fosfomycin resistance that could be leveraged to develop new strategies to inhibit FosA and potentiate fosfomycin activity.

Crystal structure of Streptococcus pyogenes EndoS, an immunomodulatory endoglycosidase specific for human IgG antibodies.

To evade host immune mechanisms, many bacteria secrete immunomodulatory enzymes. Streptococcus pyogenes, one of the most common human pathogens, secretes a large endoglycosidase, EndoS, which removes carbohydrates in a highly specific manner from IgG antibodies. This modification renders antibodies incapable of eliciting host effector functions through either complement or Fc γ receptors, providing the bacteria with a survival advantage. On account of this antibody-specific modifying activity, EndoS is being developed as a promising injectable therapeutic for autoimmune diseases that rely on autoantibodies. Additionally, EndoS is a key enzyme used in the chemoenzymatic synthesis of homogenously glycosylated antibodies with tailored Fc γ receptor-mediated effector functions. Despite the tremendous utility of this enzyme, the molecular basis of EndoS specificity for, and processing of, IgG antibodies has remained poorly understood. Here, we report the X-ray crystal structure of EndoS and provide a model of its encounter complex with its substrate, the IgG1 Fc domain. We show that EndoS is composed of five distinct protein domains, including glycosidase, leucine-rich repeat, hybrid Ig, carbohydrate binding module, and three-helix bundle domains, arranged in a distinctive V-shaped conformation. Our data suggest that the substrate enters the concave interior of the enzyme structure, is held in place by the carbohydrate binding module, and that concerted conformational changes in both enzyme and substrate are required for subsequent antibody deglycosylation. The EndoS structure presented here provides a framework from which novel endoglycosidases could be engineered for additional clinical and biotechnological applications.

Molecular determinants of agonist and antagonist signaling through the IL-36 receptor.

The IL-1 family consists of 11 cytokines that control a complex network of proinflammatory signals critical for regulating immune responses to infections. They also play a central role in numerous chronic inflammatory disorders. Accordingly, inhibiting the activities of these cytokines is an important therapeutic strategy for treating autoimmune diseases and lymphomas. Agonist cytokines in the IL-1 family activate signaling by binding their cognate receptor and then recruiting a receptor accessory protein. Conversely, antagonist cytokines bind their cognate receptor but prohibit recruitment of receptor accessory protein, which precludes functional signaling complexes. The IL-36 subfamily of cytokines is the most diverse, including three agonists and at least one antagonist, and is the least well-characterized group within this family. Signaling through the IL-36 receptor directly stimulates dendritic cells and primes naive CD4 T cells for Th1 responses. Appropriately balanced IL-36 signaling is a critical determinant of skin and lung health. IL-36 signaling has been presumed to function analogously to IL-1 signaling. In this study, we have defined molecular determinants of agonist and antagonist signaling through the IL-36 receptor. We present the crystal structure of IL-36γ, which, to our knowledge, is the first reported structure of an IL-36 agonist. Using this structure as a guide, we designed a comprehensive series of IL-36 agonist/antagonist chimeric proteins for which we measured binding to the IL-36 receptor/IL-1 receptor accessory protein complex and functional activation and inhibition of signaling. Our data reveal how the fine specificity of IL-36 signaling is distinct from that of IL-1.

Structure of Clostridium difficile PilJ exhibits unprecedented divergence from known type IV pilins.

Type IV pili are produced by many pathogenic Gram-negative bacteria and are important for processes as diverse as twitching motility, cellular adhesion, and colonization. Recently, there has been an increased appreciation of the ability of Gram-positive species, including Clostridium difficile, to produce Type IV pili. Here we report the first three-dimensional structure of a Gram-positive Type IV pilin, PilJ, demonstrate its incorporation into Type IV pili, and offer insights into how the Type IV pili of C. difficile may assemble and function. PilJ has several unique structural features, including a dual-pilin fold and the incorporation of a structural zinc ion. We show that PilJ is incorporated into Type IV pili in C. difficile and present a model in which the incorporation of PilJ into pili exposes the C-terminal domain of PilJ to create a novel interaction surface.

Clonal spread of highly successful ST15-CTX-M-15 Klebsiella pneumoniae in companion animals and horses.

OBJECTIVES: To investigate the clinical relevance and molecular epidemiology of extended-spectrum ß-lactamase (ESBL)-producing Klebsiella species in animals. METHODS: Antimicrobial susceptibilities and presence of ESBLs were examined among Klebsiella spp. (n = 1519) from clinical samples (>1200 senders from Germany and other European countries) mainly from companion animals and horses from October 2008 to March 2010. Multilocus sequence typing (MLST) and PFGE were performed including human isolates for comparative purposes. RESULTS: The overall ESBL rate was 8% for Klebsiella pneumoniae subsp. pneumoniae. Most K. pneumoniae subsp. pneumoniae ESBL producers were isolated from soft tissue infections (29.3%) and urinary tract infections (14.9%). The major ESBL type was CTX-M-15 (85.4%), located on different plasmid scaffolds (HI2, I1, FIA, FIB, FII, A/C, R and N). Other ESBL genes, such as bla(CTX-M-1) (5.6%), bla(CTX-M-3), bla(CTX-M-9), bla(SHV-2) and bla(SHV-12) (1.1% each), were also detected. Additional resistances, e.g. to fluoroquinolones (89.9%), were frequently present. ST15-CTX-M-15, a clonal group that recently emerged in humans, accounted for 75.8% of the strains analysed by MLST and there was evidence for nosocomial events in five veterinary clinics. Human ST15-CTX-M-15 strains shared PFGE clusters with animal isolates, suggesting the dissemination of this clonal group between both populations. CONCLUSIONS: Our data indicate a wide spread of ST15-CTX-M-15 K. pneumoniae subsp. pneumoniae, which should be considered as a zoonotic agent of high clinical relevance for humans and animals. Further research should be undertaken to unravel both microevolutionary and biological aspects probably contributing to this global success.