Discovery of a novel and conserved Plasmodium falciparum exported protein that is important for adhesion of PfEMP1 at the surface of infected erythrocytes

Plasmodium falciparum virulence is linked to its ability to sequester in post‐capillary venules in the human host. Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is the main variant surface antigen implicated in this process. Complete loss of parasite adhesion is linked to a large subtelomeric deletion on chromosome 9 in a number of laboratory strains such as D10 and T9‐96. Similar to the cytoadherent reference line FCR3, D10 strain expresses PfEMP1 on the surface of parasitized erythrocytes, however without any detectable cytoadhesion. To investigate which of the deleted subtelomeric genes may be implicated in parasite adhesion, we selected 12 genes for D10 complementation studies that are predicted to code for proteins exported to the red blood cell. We identified a novel single copy gene (PF3D7_0936500) restricted to P. falciparum that restores adhesion to CD36, termed here virulence‐associated protein 1 (Pfvap1). Protein knockdown and gene knockout experiments confirmed a role of PfVAP1 in the adhesion process in FCR3 parasites. PfVAP1 is co‐exported with PfEMP1 into the host cell via vesicle‐like structures called Maurer's clefts. This study identifies a novel highly conserved parasite molecule that contributes to parasite virulence possibly by assisting PfEMP1 to establish functional adhesion at the host cell surface.     

Stepwise reduction of functional spinal structures increase range of motion and change lordosis angle

Many investigators have performed studies on specific defect situations or determined the contribution on isolated structures. Investigating the contribution of functional structures requires obtaining the kinematic response directly on spinal segments. The purpose of this study was to quantify the function of anatomical components on lumbar segments for different loading magnitudes. Eight spinal segments (L4-5) with a median age of 52 years (ranging from 38 to 59 years) and a low degree of disc degeneration were utilized for the in vitro testing. Specimens were mounted in a custom-built spine tester and loaded with pure moments (1-10 N m) to move within three anatomical planes at a loading rate of 1.0 degrees /s. Anatomy was successively reduced by: ligaments, facet capsules, joints and nucleus. Data were evaluated for range of motion, neutral zone and lordosis angle. Transection of posterior ligaments predominantly increased specimen flexion for all bending moments applied. Supraspinous ligament also indicated to resist in extension slightly, whereas the facet capsules did not. Facet joints contributed to axial rotation, but not in lateral bending. The anterior longitudinal ligament was found to slightly resist in axial rotation, but strongly in extension. Nucleotomy caused largest increase of all movements. The unloaded posture of the specimens changed after ligament dissection, indicating ligament pretension. The region of lumbar spine is interesting for finite element (FE) simulation due to the high evidence of disc degeneration and injuries. This study may help to understand the function of specific anatomical structures and assists in FE model calibration. We suggest to start a calibration procedure for such models with the smallest functional structure (annulus) and to cumulatively add further structures.     

Genetic and biochemical characterization of the cell wall hydrolase activity of the major secreted protein of Lactobacillus rhamnosus GG

Lactobacillus rhamnosus GG (LGG) produces two major secreted proteins, designated here Msp1 (LGG_00324 or p75) and Msp2 (LGG_00031 or p40), which have been reported to promote the survival and growth of intestinal epithelial cells. Intriguingly, although each of these proteins shares homology with cell wall hydrolases, a physiological function that correlates with such an enzymatic activity remained to be substantiated in LGG. To investigate the bacterial function, we constructed knock-out mutants in the corresponding genes aiming to establish a genotype to phenotype relation. Microscopic examination of the msp1 mutant showed the presence of rather long and overly extended cell chains, which suggests that normal daughter cell separation is hampered. Subsequent observation of the LGG wild-type cells by immunofluorescence microscopy revealed that the Msp1 protein accumulates at the septum of exponential-phase cells. The cell wall hydrolyzing activity of the Msp1 protein was confirmed by zymogram analysis. Subsequent analysis by RP-HPLC and mass spectrometry of the digestion products of LGG peptidoglycan (PG) by Msp1 indicated that the Msp1 protein has D-glutamyl-L-lysyl endopeptidase activity. Immunofluorescence microscopy and the failure to construct a knock-out mutant suggest an indispensable role for Msp2 in priming septum formation in LGG.     

Polymorphisms in base-excision repair and nucleotide-excision repair genes in relation to lung cancer risk

Polymorphisms in DNA repair genes may be associated with differences in DNA repair capacity, thereby influencing the individual susceptibility to smoking-related cancer. We investigated the association of 10 base-excision and nucleotide-excision repair gene polymorphisms (XRCC1 -77 T/C, Arg194Trp, Arg280His and Arg399Gln; APE1 Asp148Glu; OGG1 Ser326Cys; XPA -4 G/A; XPC PAT; XPD Asp312Asn and Lys751Gln) with lung cancer risk in Caucasians. Genotypes were determined by PCR-RFLP and PCR-single base extension assays in 110 lung cancer patients and 110 age- and sex-matched controls, and the results were analyzed using logistic regression adjusted for relevant covariates. A significant association between the APE1 Asp148Glu polymorphism and lung cancer risk was found, with adjusted odds ratios (OR) of 3.38 (p=0.001) for the Asp/Glu genotype and 2.39 (p=0.038) for the Glu/Glu genotype. Gene-smoking interaction analyses revealed a statistically significant interaction between cumulative cigarette smoking and the XRCC1 Arg399Gln and XPD Lys751Gln polymorphisms: these polymorphisms were significantly associated with lung cancer in nonsmokers and light smokers (<25 PY; OR=4.92, p=0.021 for XRCC1 399 Gln/Gln; OR=3.62, p=0.049 for XPD 751 Gln/Gln), but not in heavy smokers (> or =25 PY; OR=0.68, p=0.566 for XRCC1 399 Gln/Gln; OR=0.46, p=0.295 for XPD 751 Gln/Gln). Both the XRCC1 Arg194Trp and Arg280His as well as the OGG1 Ser326Cys heterozygous genotypes were associated with a significantly reduced risk for lung cancer (OR=0.32, p=0.024; OR=0.25, p=0.028; OR=0.51, p=0.033, respectively). No associations with lung cancer risk were found for the XRCC1 -77 T/C, the XPA -4 G/A and the XPC PAT polymorphisms. In conclusion, the APE1 Asp148Glu polymorphism is highly predictive for lung cancer, and cumulative cigarette smoking modifies the associations between the XRCC1 Arg399Gln and the XPD Lys751Gln polymorphisms and lung cancer risk.     

Synthesis and characterization of 5,6,7,8-tetrahydroquinoline C5a receptor antagonists

A novel series of substituted 2-aryl-5-amino-5,6,7,8-tetrahydroquinoline C5a receptor antagonists is reported. Synthetic routes were developed that allow the substituents on the tetrahydroquinoline core to be efficiently varied, facilitating determination of structure-activity relationships. Members of the series display high binding affinity for the C5a receptor and are potent functional antagonists.     

On the Nature of the Heat Resistance of Thermophilic Bacteria

The importance of inorganic ions for the heat stability of thermophilic bacteria was investigated. Cells of Bacillus stearothermophilus, strain 1503, were incubated at elevated temperatures in various media and the number of surviving organisms was determined at suitable intervals. The bacteria rapidly died at temperatures ordinarily employed for their cultivation if the surrounding medium lacked calcium ions. Besides calcium ions, potassium and phosphate ions and glucose, or some other energy source, seemed to be required for the heat stability of the cells. A chemically defined stabilizing medium with these components was developed for the above-mentioned strain. When any component of this medium was excluded, the heat resistance of this organism was lost. This medium had a stabilizing effect also on the cells of three other strains of B. stearothermophilus. These requirements suggest that the heat stability of thermophilic bacteria is attributable to an active transport of calcium ions from the environment into the cells.     

Design of a medical record review study on the incidence and preventability of adverse events requiring a higher level of care in Belgian hospitals

ABSTRACT: BACKGROUND: Adverse events are unintended patient injuries that arise from healthcare management resulting in disability, prolonged hospital stay or death. Adverse events that require intensive care admission imply a considerable financial burden to the healthcare system. The epidemiology of adverse events in Belgian hospitals has never been assessed systematically. FINDINGS: A multistage retrospective review study of patients requiring a transfer to a higher level of care will be conducted in six hospitals in the province of Limburg. Patient records are reviewed starting from January 2012 by a clinical team consisting of a research nurse, a physician and a clinical pharmacist. Besides the incidence and the level of causation and preventability, also the type of adverse events and their consequences (patient harm, mortality and length of stay) will be assessed. Moreover, the adequacy of the patient records and quality/usefulness of the method of medical record review will be evaluated. DISCUSSION: This paper describes the rationale for a retrospective review study of adverse events that necessitate a higher level of care. More specifically, we are particularly interested in increasing our understanding in the preventability and root causes of these events in order to implement improvement strategies. Attention is paid to the strengths and limitations of the study design.     

Synthesis and SAR of selective small molecule neuropeptide Y Y2 receptor antagonists

Highly potent and selective small molecule neuropeptide Y Y2 receptor antagonists are reported. The systematic SAR exploration of a hit molecule N-(4-ethoxyphenyl)-4-[hydroxy(diphenyl)methyl]piperidine-1-carbothioamide, identified from HTS, led to the discovery of highly potent NPY Y2 antagonists 16 (CYM 9484) and 54 (CYM 9552) with IC(50) values of 19 nM and 12 nM respectively.     

Specific regulation of lipocalin-type prostaglandin D synthase in mouse heart by estrogen receptor beta

Estrogens have important physiological roles in the cardiovascular system. We use DNA microarray technology to study the molecular mechanism of estrogen action in the heart and to identify novel estrogen-regulated genes. In this investigation we identify genes that are regulated by chronic estrogen treatment of mouse heart. We present our detailed characterization of one of these genes, lipocalin-type prostaglandin D synthase (L-PGDS). Northern and Western blot analysis revealed that L-PGDS was induced both by acute and chronic estrogen treatment. Northern blot analysis, using estrogen receptor (ER)-disrupted mice, suggests that L-PGDS is specifically induced by ERbeta in vivo. In further support of ERbeta-selective regulation, we identify a functional estrogen-responsive element in the L-PGDS promoter, the activity of which is up-regulated by ERbeta, but not by ERalpha. We demonstrate that a one-nucleotide change (A to C) in the L-PGDS estrogen-responsive element affects receptor selectivity.     

Autolyse der zellwand bei den gameten von Chlamydomonas reinhardii

Zusammenfassung An der Gametenverschmelzung bei der heterothallischen, isogamen Grünalge Chlamydomonas reinhardii ist, wie an der Befruchtung bei höheren Organismen, ein lytischer Faktor beteiligt. Während des Kontaktes von und Gameten oder während einer, Isoagglutination von Gameten des einen Paarungstyps mit den isolierten Geißeln vom entgegengesetzten Paarungstyp wurde ein hitzelabiler, lytischer Faktor ins Nährmedium abgegeben. Auch Extrakte aus vegetativen und generativen Zellen von C. reinhardii enthielten lytische Aktivität. Unter der Einwirkung des extrahierten oder des sekretierten Autolysins fand eine partielle Lyse der Zellwände von Gameten und Zoosporen statt, die mit der Freisetzung von Protoplasten verbunden war. Die Präparate mit lytischer Aktivität lösten außerdem die Wände der Zoosporangien von C. reinhardii vollständig auf und setzten dabei Zoosporen frei.

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Autolysis of the cell wall from the gametes of Chlamydomonas reinhardii

Summary As in fertilization of higher organisms a lytic factor is involved in the mating reaction of the heterothallic isogamous green alga Chlamydomonas reinhardii. Lytic activity was found in the medium after copulation of and gametes, after isoaggllutination of gametes with isolated flagella, and of gametes with isolated flagella. A lytic factor could also be extracted from vegetative and generative cells of C. reinhardii. Partial lysis of cell walls from vegetative or generative cells accompanied by the release of protoplasts, and complete lysis of the walls from zoosporangia followed by the release of zoospores, were observed in the presence of the autolysin secreted by gametes under the above mentioned conditions or extracted from vegetative and generative cells.