bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of the Biomechanical Properties of T4 Pili Expressed by Streptococcus pneumoniae—A Comparison between Helix‐like and Open Coil‐like Pili
Authors: Castelain Mickaël , Koutris Efstratios , Andersson Magnus , Wiklund Krister , Björnham Oscar , Schedin Staffan , Axner Ove 
Published: June 2009

AbstractAdhesion strategies: Open coil‐like T4 pili use different adhesion strategies in the presence of external forces (see figure) compared to the helix‐like P pili. When exposed to significant forces, bacteria expressing helix‐like pili remain attached by distributing the external force among a multitude of pili, whereas bacteria expressing open coil‐like pili sustain large forces primarily by their multitude of binding adhesins.magnified imageBacterial adhesion organelles, known as fimbria or pili, are expressed by Gram‐positive as well as Gram‐negative bacteria families. These appendages play a key role in the first steps of the invasion and infection processes, and they therefore provide bacteria with pathogenic abilities. To improve the knowledge of pili‐mediated bacterial adhesion to host cells and how these pili behave under the presence of an external force, we first characterize, using force measuring optical tweezers, open coil‐like T4 pili expressed by Gram‐positive Streptococcus pneumoniae with respect to their biomechanical properties. It is shown that their elongation behavior can be well described by the worm‐like chain model and that they possess a large degree of flexibility. Their properties are then compared with those of helix‐like pili expressed by Gram‐negative uropathogenic Escherichia coli (UPEC), which have different pili architecture. The differences suggest that these two types of pili have distinctly dissimilar mechanisms to adhere and sustain external forces. Helix‐like pili expressed by UPEC bacteria adhere to host cells by single adhesins located at the distal end of the pili while their helix‐like structures act as shock absorbers to dampen the irregularly shear forces induced by urine flow and to increase the cooperativity of the pili ensemble, whereas open coil‐like pili expressed by S. pneumoniae adhere to cells by a multitude of adhesins distributed along the pili. It is hypothesized that these two types of pili represent different strategies of adhering to host cells in the presence of external forces. When exposed to significant forces, bacteria expressing helix‐like pili remain attached by distributing the external force among a multitude of pili, whereas bacteria expressing open coil‐like pili sustain large forces primarily by their multitude of binding adhesins which presumably detach sequentially.
A Novel Heavy‐Atom Label for Side‐Specific Peptide Iodination: Synthesis, Membrane Incorporation and X‐ray Reflectivity
Authors: Schneggenburger Philipp E. , Beerlink André , Worbs Brigitte , Salditt Tim , Diederichsen Ulf 
Published: June 2009

AbstractA novel iodine peptide label for X‐ray analysis of membrane‐active peptide structures is applied to solid‐phase peptide synthesis. The resulting pore‐structured labeled peptide as well as a non‐labeled reference were reconstituted in lipid bilayer stacks (see scheme). The results indicate the exhibition of a membrane‐spanning β5.6‐double helical peptide structure and illustrate the quality of the new label.magnified imageStructural parameters, such as conformation, orientation and penetration depth of membrane‐bound peptides and proteins that may function as channels, pores or biocatalysts, are of persistent interest and have to be probed in the native fluid state of a membrane. X‐ray scattering in combination with heavy‐atom labeling is a powerful and highly appropriate method to reveal the position of a certain amino acid residue within a lipid bilayer with respect to the membrane normal axis up to a resolution of several Ångstrøm. Herein, we report the synthesis of a new iodine‐labeled amino acid building block. This building block is intended for peptide incorporation to provide high intensities for electron density difference analysis of X‐ray reflectivity data and improve the labeling potential for the lipid bilayer head‐group and water region. The novel building block as well as the commercially available non‐iodinated analogue, required for X‐ray scattering, was implemented in a transmembrane peptide motif via manual solid‐phase peptide synthesis (SPPS) following the fluorenylmethyloxycarbonyl (Fmoc)‐strategy. The derived peptides were reconstituted in lipid vesicles as well as in highly aligned multilamellar lipid stacks and investigated via circular dichroism (CD) and X‐ray reflectivity. Thereby, it has been revealed that the bulky iodine probe neither causes conformational change of the peptide structure nor lamellar disordering of the membrane complexes.
Microscopic and Spectroscopic Observations in the Bio‐Nanoworld
Authors: Hinterdorfer Peter , Pohl Peter , Schütz Gerhard 
Published: June 2009

AbstractBiophysics in Linz: In February biophysicists from across the world converged on Linz for two biophysical conferences. The city which is the Cultural Capital of Europe 2009, provided the perfect environment for fruitful discussions on single‐molecule techniques in biophysics, bio‐nanotechnology, cell biology, and drug discovery.magnified image
Platelet‐activating factor‐stimulated production of reactive oxygen species in ovarian granulosa cells from periovulatory follicles
Authors: Xu Jinxian , Krüger Burkhard , Vernunft Andreas , Löhrke Berthold , Viergutz Torsten 
Published: June 2009

AbstractThe platelet‐activating factor (PAF) is a proinflammatory lipid present in the fluid of ovarian Graafian follicle. Ovarian blockage of the PAF receptor (PAFr) reduces ovulations in the rat whereas underlying mechanism is poorly understood. Mural granulosa cells (MGC) were mechanically isolated from the theca interna of bovine periovulatory follicle. The mRNA abundance for PAFr, progesterone receptor and cyclooxygenase‐2 were measured by real‐time PCR. Cytosolic calcium (Ca2+) concentration was assayed by microscopy using Fura‐2 AM as indicator, 8‐isoprostaglandin F2α(8‐isoPGF2α) by an ELISA kit. Fluorescent products arising from intracellular oxidation of hydroethidine (HE) and dihydrorhodamine (DHR) were quantified by flow cytometry. The cells expressed PAFr mRNA and PAFr protein and responded to cPAF (nonhydrolyzable form of PAF) with a pulsating increase in Ca2+, demonstrating functional PAFr. Elevation of Ca2+was reversed by WEB‐2086, an inverse PAFr agonist. cPAF elevated the level of 8‐isoPGF2αin the medium of MGC cultured with luteinizing hormone (LH). cPAF alone had no significant influence on the oxidation of HE and DHR, or 8‐isoPGF2αlevel. In MGC from vital periovulatory follicle, PAF and LH signaling plays an important role in regulating the production of excessive oxidants. Blockage of PAFr seems to interfere with these regulatory processes essential for ovulation. © 2009 International Society for Advancement of Cytometry
Simultaneous flow cytometric quantification of plant nuclear DNA contents over the full range of described angiosperm 2C values
Authors: Galbraith David W. 
Published: June 2009

AbstractFlow cytometry provides a rapid, accurate, and simple means to determine nuclear DNA contents (C‐value) within plant homogenates. This parameter is extremely useful in a number of applications in basic and applied plant biology; for example, it provides an important starting point for projects involving whole genome sequencing, it facilitates characterization of plant species within natural and agricultural settings, it allows facile identification of engineered plants that are euploid or that represent desired ploidy classes, it points toward studies concerning the role of C‐value in plant growth and development and in response to the environment and in terms of evolutionary fitness, and, in uncovering new and unexpected phenomena (for example endoreduplication), it uncovers new avenues of scientific enquiry. Despite the ease of the method, C‐values have been determined for only around 2% of the described angiosperm (flowering plant) species. Within this small subset, one of the most remarkable observations is the range of 2C values, which spans at least two orders of magnitude. In determining C‐values for new species, technical issues are encountered which relate both to requirement for a method that can provide accurate measurements across this extended dynamic range, and that can accommodate the large amounts of debris which accompanies flow measurements of plant homogenates. In this study, the use of the Accuri C6 flow cytometer for the analysis of plant C‐values is described. This work indicates that the unusually large dynamic range of the C6, a design feature, coupled to the linearity of fluorescence emission conferred by staining of nuclei using propidium iodide, allows simultaneous analysis of species whose C‐values span that of almost the entire described angiosperms. © 2009 International Society for Advancement of Cytometry
Disease‐specific biomarker discovery by aptamers
Authors: Ulrich Henning , Wrenger Carsten 
Published: June 2009

AbstractRNA and DNA aptamers developed by an in vitro selection process, Systematic Evolution of Ligands by EXponential enrichment (SELEX), comprise a novel class of high‐affinity and specific capture agents, which can be easily modified for cytometry and in vivo applications. A novel application of this technique (Cell SELEX) explores the expression of cell surface epitopes that differ between two given cell types or between healthy and diseased cells. Using whole cells as targets, aptamer libraries can be identified that bind to biomarkers expressed by target cells and not by any other cells. Aptamers have been developed that specifically interact with cell surface epitopes of trypanosomes or distinguish between the differences in molecular signature of somatic and cancer cells. Aside from its use for target cell identification by image and flow cytometry and laser‐scanning microscopy, aptamers can be used for ligand‐mediated purification and identification of their binding proteins in target cell membranes. In this review, we discuss an approach for the development of aptamers targeting parasite‐derived surface proteins of Trypanosoma and Plasmodium. © 2009 International Society for Advancement of Cytometry
Mauerwerkstrockenlegung: Analyse – Methoden – Überprüfung
Authors: Balak Michael 
Published: June 2009

AbstractAufgrund des äußerst komplexen Fachgebietes der Mauerwerkstrockenlegung und den damit verbundenen häufigen Fehlschlägen in der Praxis sind vor Durchführung von Trockenlegungsmaßnahmen eine umfangreiche Bauwerksdiagnose und die Erstellung eines Sanierungskonzeptes sowie in weiterer Folge einer Sanierungsdetailplanung erforderlich. Die Besonderheiten und Anwendungsgrenzen der verschiedenen Horizontalabdichtungsmethoden und der flankierenden Maßnahmen zur Mauerwerkstrockenlegung werden aufgezeigt. Weiterhin wird auf die Überprüfungsmöglichkeiten von Trockenlegungsmaßnahmen hingewiesen.
Massive Bestandsdecken gründerzeitlicher Bausubstanz
Authors: Kolbitsch Andreas 
Published: June 2009

AbstractZahlreiche Zustandsbewertungen an Objekten der Gründerzeit, also der Bauphase von ca. 1850 bis 1918, zeigten, dass ab etwa 1870 neuere Typen von Massivdecken unterschiedlichster Ausführung verwendet wurden, wobei unter den sogenannten “Patentdecken” Systeme mit keramischen Füllkörpern vorherrschen. Diese Deckensysteme sind in der älteren und neueren Literatur nur teilweise erfasst, die konstruktive Bewertung setzt daher in vielen Fällen eine genaue Bestandsanalyse voraus.Der vorliegende Beitrag soll die anhand bisheriger Untersuchungen gewonnenen Erfahrungen aufzeigen und exemplarische Bewertungsansätze vorstellen.
Mauerwerksdruckfestigkeit – Bestimmung bei Bestandsobjekten
Authors: Pech Anton , Zach Franz 
Published: June 2009

AbstractZum Nachweis der vertikalen, aber natürlich auch der horizontalen Tragsicherheit von Mauerwerksgebäuden des Bestandes ist es unerlässlich, entsprechende und für das Gesamtobjekt relevante Festigkeitskennwerte zu ermitteln. Diese können entweder direkt in der Bestimmung der charakteristischen Druckfestigkeit und der Scherfestigkeit liegen, werden üblicher Weise jedoch über die Komponentenfestigkeiten und durch Normen gesicherte Beziehungen definiert. Für die Praxis wurden dafür einfache Prüfverfahren entwickelt, die durch zahlreiche Anwendungen erprobt und ständige Kontrollüberprüfungen abgesichert sind.
Mauerwerksverfestigung mittels Kunstharzen
Authors: Pohlplatz Klaus 
Published: June 2009

AbstractIm Rahmen eines Forschungsprojektes wurden umfangreiche Untersuchungen an Kellerwänden (Bestandmauerwerk) und an Prüfkörpern durchgeführt. Es hat sich gezeigt, dass eine verfestigende Wirkung bei allen Harzen und Bohrlochrastern eintritt. Eine Abdichtungswirkung von organischen Injektionsmitteln gegen kapillar aufsteigende Feuchtigkeit ist bei einem engen Bohrlochraster ebenfalls gegeben. Die Ergebnisse der Untersuchungen zeigen allerdings für die einzelnen Harze und Injektionsraster ein sehr unterschiedliches Bild, so dass eine pauschale Beurteilung der Produkte nicht möglich ist und die Hersteller gefordert sind, genaue Angaben hinsichtlich Bohrlochraster, Injektionsmittelverbrauch und maximalen Durchfeuchtungsgrad zu liefern.
Der Meier Öko‐Kalkstein® als Beispiel einer Produktneuentwicklung im Bereich der Mauersteine aus Beton nach DIN EN 771‐3
Authors: Schrenk Johannes , Maier Martin 
Published: June 2009

AbstractMauersteine aus Beton werden seit vielen Jahrzehnten auf dem Markt angeboten und sind sowohl den Planern und Architekten als auch den Verarbeitern und Bauherrn bekannt. Normalerweise bestehen sie aus verschiedenen Gesteinskörnungen und ‐mehlen und werden durch das Bindemittel Zement zusammengehalten, darüber hinaus enthalten sie oft Flugasche oder Recyclingprodukte. Da sich ihre Eigenschaften über die Jahre hinweg nicht sonderlich geändert oder gar verbessert haben, sind sie mit der Zeit oft nur noch für untergeordnete Aufgaben wie Kellermauerwerk, unbeheizte Anbauten, Garagen u. ä. verwendet worden. Obwohl diese Art von Mauersteinen über ein hohes Potenzial in Bezug auf die Zusammensetzung und Struktur und die daraus resultierenden bauphysikalischen Eigenschaften verfügt, gelang es zumeist nicht, sie aus diesem “Dornröschenschlaf” zu wecken und ihr neues Leben einzuhauchen. Dass diese Steinart aber durchaus eine Zukunft besitzt, zeigt eine Entwicklung der letzten Jahre, die die Firma Meier Betonwerke GmbH aus Lauterhofen in der Oberpfalz (Bayern) vorangetrieben und durch mehrere bauaufsichtliche Zulassungen im Jahre 2008 zunächst abgeschlossen hat. Der neue Stein nennt sich zu Recht Meier Öko‐Kalkstein® und soll in diesem Beitrag näher beschrieben werden. Er ist zugleich ein Synonym für andere Entwicklungen in dieser Mauerwerksparte, da er auch als Planstein und als Großblock produziert werden kann und damit auch im Trend liegt, da klassisches, kleinformatiges Mauerwerk mit 12‐mm‐Fugen sich seit Jahren auf dem Rückzug befindet.
Einbruchhemmung – Mauerwerk bietet massiven Schutz
Authors: Schwieger Hartmut 
Published: June 2009

AbstractAlle zwei Minuten passiert in Deutschland ein Einbruch. Die Summe der jährlich durch Einbrüche in Wohnungen und Gewerbe verursachten Schäden beträgt rund 650 Mio. €, davon 410 Mio. € allein im privaten Bereich. Der durchschnittliche Schaden eines Einbruchs im privaten Bereich beträgt dabei rund 1000 € [1]. Bei Gewerbeobjekten beträgt der Durchschnittsschaden ca. 2600 € [2]. Dem vorbeugenden baulichen Einbruchschutz kommt damit hohe Bedeutung zu. Kalksandstein‐Mauerwerk [3] bietet aufgrund seiner hoher Steindruckfestigkeit die Voraussetzung zur Befestigung geeigneter Tür‐ und Fensterelemente.
Vitamin D in diabetes mellitus—a new field of knowledge poised for D‐velopment
Authors: Alfonso B. , Liao E. , Busta A. , Poretsky L. 
Published: June 2009

AbstractThis commentary reviews the current state of knowledge regarding the role of vitamin D in the pathogenesis of diabetes mellitus. In type 1 diabetes mellitus or in adult onset latent autoimmune diabetes (LADA), vitamin D exhibits immunomodulatory actions, influencing the activity of lymphocytes and interleukins. In type 2 diabetes mellitus vitamin D appears to act through different mechanisms, affecting insulin secretion and insulin sensitivity through its effects on the β cells, mediators of inflammation and parathyroid hormone. Much work remains to be done in this new field of knowledge before the role of vitamin D in the pathogenesis of diabetes mellitus is completely understood. Copyright © 2009 John Wiley & Sons, Ltd.
Leptin and endothelin‐1 mediated increased extracellular matrix protein production and cardiomyocyte hypertrophy in diabetic heart disease
Authors: Majumdar Pijush , Chen Shali , George Biju , Sen Subhrojit , Karmazyn Morris , Chakrabarti Subrata 
Published: June 2009

AbstractBackgroundWe investigated the role of leptin and its interaction with endothelin 1 (ET‐1) in fibronectin (FN) synthesis and cardiomyocyte hypertrophy, two characteristic features of diabetic cardiomyopathy.MethodsEndothelial cells [human umbilical vein endothelial cells (HUVECs)] were examined for FN production and neonatal rat cardiomyocytes for hypertrophy, following incubation with glucose, ET‐1, leptin and specific blockers. FN, ET‐1, leptin and leptin receptors mRNA expression and FN protein were measured. Myocytes were also morphometrically examined. Furthermore, hearts from streptozotocin‐diabetic rats were analysed.ResultsGlucose caused increased FN mRNA and protein expression in HUVECs and cardiomyocytes hypertrophy along with upregulation of ET‐1 mRNA, leptin mRNA and protein. Glucosemimetic effects were seen with leptin and ET‐1. Leptin receptor antagonist (leptin quadruple mutant) and dual endothelin A endothelin B (ETA/ETB) receptor blocker bosentan normalized such abnormalities. Hearts from the diabetic animals showed hypertrophy and similar mRNA changes.ConclusionThese data indicate that in diabetes increased FN production and cardiomyocyte hypertrophy may be mediated through leptin with its interaction with ET‐1. Copyright © 2009 John Wiley & Sons, Ltd.
Comparison of insulin detemir and insulin glargine using a basal‐bolus regimen in a randomized, controlled clinical study in patients with type 2 diabetes
Authors: Raskin Philip , Gylvin Titus , Weng Wayne , Chaykin Louis 
Published: June 2009

AbstractBackgroundThis treat‐to‐target study compared the efficacy and safety of insulin detemir (IDet) and insulin glargine (IGla) in a basal‐bolus (insulin aspart) regimen in type 2 diabetes.Methods385 patients were randomized 2 : 1 (IDet : IGla). Non‐inferiority of IDet to IGla was determined by HbA1c 95% CI upper limit <0.4.ResultsIDet and IGla showed similar efficacy in HbA1c reduction at 26 weeks, as the non‐inferiority criterion was met at 26 weeks (LS mean [Det–Gla]: 0.207; 95% CI: 0.0149,0.3995). It appeared that IGla in some cases did better than IDet in terms of HbA1c, but the difference (0.207%) was not clinically meaningful. Based on the CONSORT guideline, non‐inferiority analysis using the LOCF approach was inconclusive regarding possible inferiority of delta 0.4 (LS mean of [Det–Gla]: 0.307; 95% CI: 0.1023, 0.5109). HbA1c decreased significantly from baseline in IDet (−1.1% [26 weeks], −0.9% [LOCF], p < 0.001) and in IGla (−1.3% [26 weeks, LOCF], p < 0.001). Final HbA1c were 7.1% (26 weeks) and 7.3% (LOCF) in IDet, and 6.9% (26 weeks) and 7.0% (LOCF) in IGla. Final FPG were 130 mg/dL (26 weeks) and 135 mg/dL (LOCF) in IDet, and 134 mg/dL (26 weeks) and 137 mg/dL (LOCF) in IGla. There was significantly less weight gain in IDet‐treated patients (1.2 ± 3.96 kg versus 2.7 ± 3.94 kg, p = 0.001). Hypoglycemia risk was comparable between groups. The majority of IDet‐treated patients (87.4%) remained on a once‐daily basal insulin regimen throughout the study.ConclusionsIDet and IGla were both effective and safe treatments for glycemic control in a basal‐bolus regimen for type 2 diabetes. Clinically significant reductions in HbA1c were achieved in both groups, but with significantly less weight gain in the IDet group at comparable basal insulin dosage. Copyright © 2009 John Wiley & Sons, Ltd.
Paternal deprivation induces dendritic and synaptic changes and hemispheric asymmetry of pyramidal neurons in the somatosensory cortex
Authors: Pinkernelle Josephine , Abraham Andreas , Seidel Katja , Braun Katharina 
Published: June 2009

AbstractSimilar to maternal care, paternal care is a source of neonatal sensory stimulation, which in primates and rodents has been shown to be essential for developing structure and function of sensory cortices. The aim of our study in the biparental rodent Octodon degus was to assess the impact of paternal deprivation on dendritic and synaptic development in the somatosensory cortex. We (i) quantified the amount of paternal care in relation to total parental investment and (ii) compared dendritic and synaptic development of pyramidal neurons in the somatosensory cortex of animals raised by a single mother or by both parents. On the behavioral level we show that paternal care comprises 37% of total parent‐offspring interactions, and that the somatosensory stimulation provided by the fathers primarily consists of huddling, licking/grooming, and playing. On the morphological level we found that, compared with offspring raised by both parents (mother and father), the father‐deprived animals displayed significantly reduced spine numbers on the basal dendrites of pyramidal neurons. Furthermore, paternal deprivation induces hemispheric asymmetry of the dendritic morphology of somatosensory pyramidal neurons. Father‐deprived animals show shorter and less complex basal dendrites in the left somatosensory cortex compared with the right hemisphere. These findings indicate that paternal deprivation results in delayed or retarded dendritic and synaptic development of somatosensory circuits. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009
Gap junctions are involved in cell migration in the early postnatal subventricular zone
Authors: Marins Mônica , Xavier Anna L.R. , Viana Nathan B. , Fortes Fábio S.A. , Fróes Maira M. , Menezes João R.L. 
Published: June 2009

AbstractThe massive migration of neuroblasts and young neurons through the anterior extension of the postnatal subventricular zone (SVZ), known as the rostral migratory stream (RMS) is still poorly understood on its molecular basis. In this work, we investigated the involvement of gap junctional communication (GJC) in the robust centrifugal migration from SVZ/RMS explants obtained from early postnatal (P4) rats. Cells were dye‐coupled in homocellular and heterocellular pairings and expressed at least two connexins, Cx 43 and 45. Treatment with the uncoupler agent carbenoxolone (CBX, 10–100 μM) reversibly reduced outgrowth from SVZ explants, while its inactive analog, glycyrhizinic acid (GZA), had no effect. Consistent with a direct effect on cell migration, time‐lapse video microscopy show that different pharmacological uncouplers cause an abrupt and reversible arrest of cell movement in explants. Our results indicate that GJC is positively involved in the migration of neuroblasts within the SVZ/RMS. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009