bluuebunny/crossref_metadata_2025 huggingface dataset:
Bor – elementare Herausforderung für Experimentatoren und Theoretiker
Authors: Albert Barbara , Hillebrecht Harald
Published: October 2009

Auch mehr als zweihundert Jahre nach der Entdeckung des Elementes Bor gibt es auf viele grundlegende Fragen in der Festkörperchemie von Bor noch keine eindeutigen Antworten. In jüngster Zeit zeigten theoretische Arbeiten zur Stabilität und Existenz bekannter und neuer Modifikationen des Elements in Verbindung mit Hochdruck‐ und Hochtemperaturexperimenten neue Aspekte. Auch auf dem Gebiet der Reaktionen von Bor mit Hauptgruppenelementen hat sich in den letzten Jahren viel getan. Aufsehen haben binäre Verbindungen wie B6O, MgB2, LiB1−x, Na3B20 oder CaB6 erregt, aber auch die elektronenpräzisen, farblosen Boridcarbide Li2B12C2, LiB13C2 und MgB12C2 sowie Graphit‐analoges BeB2C2 verdienen besonderes Augenmerk. Physikalische Eigenschaften wie Härte, Supraleitfähigkeit, Neutroneneinfangquerschnitt und Thermoelektrizität machen borreiche Verbindungen auch für Materialforschung und Anwendung attraktiv. Die größten wissenschaftlichen Herausforderungen bestehen jedoch weiterhin in der Synthese einphasiger Produkte in makroskopischen Mengen und in Form von Einkristallen, in der zweifelsfreien Identifizierung und Bestimmung von Zusammensetzung und Kristallstruktur sowie im Verständnis der elektronischen Situation. Verknüpfte Polyeder sind das dominierende Strukturelement in borreichen Verbindungen der Hauptgruppenelemente. In vielen Fällen leiten sich deren Strukturen von denen ab, die den Elementmodifikationen zugeschrieben werden. Auch diese bedürfen allerdings einer neuen, kritischen Durchsicht und Diskussion.
Heterogeneity of active sites of Ziegler‐Natta catalysts: The effect of catalyst composition on the MWD of polyethylene
Authors: Nikolaeva Marina I. , Mikenas Tatiana B. , Matsko Mikhail A. , Echevskaya Ludmila G. , Zakharov Vladimir A.
Published: October 2009

Experimental data on the molecular weight distribution (MWD) of polyethylene (PE) produced over a broad number of Ziegler‐Natta catalysts differing in composition and preparation procedure are presented. These catalysts include nonsupported TiCl3 catalyst, four types of supported titanium‐magnesium catalysts (TMC) differing in the content of titanium and the presence of various modifiers in the composition of the support, and a supported catalyst containing VCl4 as an active component instead of TiCl4. The studied catalysts produce PE with different molecular weights within a broad range of polydispersity (Mw/Mn = 2.8–16) under the same polymerization conditions. The heterogeneity of active sites of these catalysts was studied by deconvolution of experimental MWD curves into Flory components assuming a correlation between the number of Flory components and the number of active site types. Five Flory components were found for PE produced over nonsupported TiCl3 catalysts (Mw/Mn = 6.8), and three–four Flory components were found for PE produced over TMC of different composition. A minimal number of Flory components (three) was found for PE samples (Mw/Mn values from 2.8 to 3.3) produced over TMC with a very low titanium content (0.07 wt %) and TMC modified with dibutylphtalate. It was shown that five Flory components are sufficient to fit the experimental MWD curve for bimodal PE (Mw/Mn = 16) produced over VMC. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Wissen in Geschichten. Zur wechselseitigen Erhellung von Literatur, Medien und Wissenschaft
Authors: Dotzler Bernhard J.
Published: October 2009

Knowledge in Stories. On the Mutual Lucidation of Literature, Media, and Science. What are science studies for? The article faces this question by arguing, 1. that they can help to improve literary criticism, and 2. that such an improved criticism allows to recognize how knowledge, whether scientific or not, is linked with history and culture respectively. Both aspects are demonstrated by some remarks on Theodor Fontane's most famous novel, Effi Briest, and its allusions to the then newly discovered microbes on the one hand as well as to mediumistic phaenomena on the other hand.
Metabolic engineering of Clostridium acetobutylicum M5 for highly selective butanol production
Authors: Lee Jin Young , Jang Yu‐Sin , Lee Joungmin , Papoutsakis Eleftherios Terry , Lee Sang Yup
Published: October 2009

To improve butanol selectivity, Clostridium acetobutylicum M5(pIMP1E1AB) was constructed by adhE1‐ctfAB complementation of C. acetobutylicum M5, a derivative strain of C. acetobutylicum ATCC 824, which does not produce solvents due to the lack of megaplasmid pSOL1. The gene products of adhE1‐ctfAB catalyze the formation of acetoacetate and ethanol/butanol with acid re‐assimilation in solventogenesis. Effects of the adhE1‐ctfAB complementation of M5 were studied by batch fermentations under various pH and glucose concentrations, and by flux balance analysis using a genome‐scale metabolic model for this organism. The metabolically engineered M5(pIMP1E1AB) strain was able to produce 154 mM butanol with 9.9 mM acetone at pH 5.5, resulting in a butanol selectivity (a molar ratio of butanol to total solvents) of 0.84, which is much higher than that (0.57 at pH 5.0 or 0.61 at pH 5.5) of the wild‐type strain ATCC 824. Unlike for C. acetobutylicum ATCC 824, a higher level of acetate accumulation was observed during fermentation of the M5 strain complemented with adhE1 and/or ctfAB. A plausible reason for this phenomenon is that the cellular metabolism was shifted towards acetate production to compensate reduced ATP production during the largely growth‐associated butanol formation by the M5(pIMP1E1AB) strain.
Helix formation in β/δ‐hybrid peptides: Correspondence between helices of different peptide foldamer classes
Authors: Schramm Peter , Sharma Gangavaram V. M. , Hofmann Hans‐Jörg
Published: October 2009

An overview on all hydrogen‐bonded helix types, which can be expected in the novel class of β/δ‐hybrid peptides, is provided on the basis of ab initio molecular orbital theory. The results show a considerable potential of different folding patterns, which makes this novel class of peptide foldamers interesting for peptide and protein design. Thus, this study may stimulate the synthesis of such hybrid peptides. The large number of helix types found for β/δ‐hybrid peptides together with the many helices experimentally found and theoretically predicted in the other classes of peptide and hybrid peptide foldamers provide a good basis to establish general correspondence rules for their mutual exchange in peptide sequences. This is done by introduction of the concept of pattern and shape correspondence. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 94: 279–291, 2010.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Integrating the cell stress response: a new view of molecular chaperones as immunological and physiological homeostatic regulators
Authors: Henderson Brian
Published: October 2009

The response of cells to stress was first documented in the 1960s and 1970s and the molecular nature of the families of proteins that subserve this vital response, the molecular chaperones, were identified and subjected to critical study in the period from the late 1980s. This resulted in the rapidly advancing new field of protein folding and its role in cellular function. Emerging at the same time, but initially largely ignored, were reports that molecular chaperones could be released by cells and exist on the outer plasma membrane or in the body fluids. These secreted molecular chaperones were found to have intercellular signalling functions. There is now a growing body of evidence to support the hypothesis that molecular chaperones have properties ascribed to the Roman god Janus, the god of gates, doors, beginnings and endings, whose two faces point in different directions. Molecular chaperones appear to have one set of key functions within the cell and, potentially, a separate set of functions when they exist on the cell surface or in the various fluid phases of the body. Thus, it is a likely hypothesis that secreted molecular chaperones act as an additional level of homeostatic control possibly linking cellular stress to physiological systems such as the immune system. This review concentrates on three key molecular chaperones: Hsp10, Hsp60 and the Hsp70 family for which most information is available. An important consideration is the role that these proteins may play in human disease and in the treatment of human disease. Copyright © 2009 John Wiley & Sons, Ltd.
Is there a benefit to sentinel lymph node biopsy in patients with T4 melanoma?
Authors: Gajdos Csaba , Griffith Kent A. , Wong Sandra L. , Johnson Timothy M. , Chang Alfred E. , Cimmino Vincent M. , Lowe Lori , Bradford Carol R. , Rees Riley S. , Sabel Michael S.
Published: October 2009

BACKGROUND:

Controversy exists as to whether patients with thick (Breslow depth >4 mm), clinically lymph node‐negative melanoma require sentinel lymph node (SLN) biopsy. The authors examined the impact of SLN biopsy on prognosis and outcome in this patient population.

METHODS:

A review of the authors' institutional review board‐approved melanoma database identified 293 patients with T4 melanoma who underwent surgical excision between 1998 and 2007. Patient demographics, histologic features, and outcome were recorded and analyzed.

RESULTS:

Of 227 T4 patients who had an SLN biopsy, 107 (47%) were positive. The strongest predictors of a positive SLN included angiolymphatic invasion, satellitosis, or ulceration of the primary tumor. Patients with a T4 melanoma and a negative SLN had a significantly better 5‐year distant disease‐free survival (DDFS) (85.3% vs 47.8%; P < .0001) and overall survival (OS) (80% vs 47%; P < .0001) compared with those with metastases to the SLN. For SLN‐positive patients, only angiolymphatic invasion was a significant predictor of DDFS, with a hazard ratio of 2.29 (P = .007). Ulceration was not significant when examining SLN‐positive patients but the most significant factor among SLN‐negative patients, with a hazard ratio of 5.78 (P = .02). Increasing Breslow thickness and mitotic rate were also significantly associated with poorer outcome. Patients without ulceration or SLN metastases had an extremely good prognosis, with a 5‐year OS >90% and a 5‐year DDFS of 95%.

CONCLUSIONS:

Clinically lymph node‐negative T4 melanoma cases should be strongly considered for SLN biopsy, regardless of Breslow depth. SLN lymph node status is the most significant prognostic sign among these patients. T4 patients with a negative SLN have an excellent prognosis in the absence of ulceration and should not be considered candidates for adjuvant high‐dose interferon. Cancer 2009. © 2009 American Cancer Society.
Peripheral facial nerve axotomy in mice causes sprouting of motor axons into perineuronal central white matter: Time course and molecular characterization
Authors: Makwana Milan , Werner Alexander , Acosta‐Saltos Alejandro , Gonitel Roman , Pararajasingham Abirami , Ruff Crystal , Rumajogee Prakasham , Cuthill Dan , Galiano Mathias , Bohatschek Marion , Wallace Adam S. , Anderson Patrick N. , Mayer Ulrike , Behrens Axel , Raivich Gennadij
Published: October 2009

Generation of new axonal sprouts plays an important role in neural repair. In the current study, we examined the appearance, composition and effects of gene deletions on intrabrainstem sprouts following peripheral facial nerve axotomy. Axotomy was followed by the appearance of galanin+ and calcitonin gene‐related peptide (CGRP)+ sprouts peaking at day 14, matching both large, neuropeptide+ subpopulations of axotomized facial motoneurons, but with CGRP+ sprouts considerably rarer. Strong immunoreactivity for vesicular acetylcholine transporter (VAChT) and retrogradely transported MiniRuby following its application on freshly cut proximal facial nerve stump confirmed their axotomized motoneuron origin; the sprouts expressed CD44 and alpha7beta1 integrin adhesion molecules and grew apparently unhindered along neighboring central white matter tracts. Quantification of the galanin+ sprouts revealed a stronger response following cut compared with crush (day 7–14) as well as enhanced sprouting after recut (day 8 + 6 vs. 14; 14 + 8 vs. 22), arguing against delayed appearance of sprouting being the result of the initial phase of reinnervation. Sprouting was strongly diminished in brain Jun‐deficient mice but enhanced in alpha7 null animals that showed apparently compensatory up‐regulation in beta1, suggesting important regulatory roles for transcription factors and the sprout‐associated adhesion molecules. Analysis of inflammatory stimuli revealed a 50% reduction 12–48 hours following systemic endotoxin associated with neural inflammation and a tendency toward more sprouts in TNFR1/2 null mutants (P = 10%) with a reduced inflammatory response, indicating detrimental effects of excessive inflammation. Moreover, the study points to the usefulness of the facial axotomy model in exploring physiological and molecular stimuli regulating central sprouting. J. Comp. Neurol. 518:699–721, 2010. © 2009 Wiley‐Liss, Inc.
Chronic expression of PPAR‐δ by oligodendrocyte lineage cells in the injured rat spinal cord
Authors: Almad Akshata , McTigue Dana M.
Published: October 2009

The transcription factor peroxisome proliferator‐activated receptor (PPAR)‐δ promotes oligodendrocyte differentiation and myelin formation in vitro and is prevalent throughout the brain and spinal cord. Its expression after injury, however, has not been examined. Thus, we used a spinal contusion model to examine the spatiotemporal expression of PPAR‐δ in naïve and injured spinal cords from adult rats. As previously reported, PPAR‐δ was expressed by neurons and oligodendrocytes in uninjured spinal cords; PPAR‐δ was also detected in NG2 cells (potential oligodendrocyte progenitors) within the white matter and gray matter. After spinal cord injury (SCI), PPAR‐δ mRNA and protein were present early and increased over time. Overall PPAR‐δ+ cell numbers declined at 1 day post injury (dpi), likely reflecting neuron loss, and then rose through 14 dpi. A large proportion of NG2 cells expressed PPAR‐δ after SCI, especially along lesion borders. PPAR‐δ+ NG2 cell numbers were significantly higher than naive by 7 dpi and remained elevated through at least 28 dpi. PPAR‐δ+ oligodendrocyte numbers declined at 1 dpi and then increased over time such that >20% of oligodendrocytes expressed PPAR‐δ after SCI compared with ∼10% in uninjured tissue. The most prominent increase in PPAR‐δ+ oligodendrocytes was along lesion borders where at least a portion of newly generated oligodendrocytes (bromodeoxyuridine+) were PPAR‐δ+. Consistent with its role in cellular differentiation, the early rise in PPAR‐δ+ NG2 cells followed by an increase in new PPAR‐δ+ oligodendrocytes suggests that this transcription factor may be involved in the robust oligodendrogenesis detected previously along SCI lesion borders. J. Comp. Neurol. 518:785–799, 2010. © 2009 Wiley‐Liss, Inc.
Localization of a GABA transporter to glial cells in the developing and adult olfactory pathway of the moth Manduca sexta
Authors: Oland Lynne A. , Gibson Nicholas J. , Tolbert Leslie P.
Published: October 2009

Glial cells have several critical roles in the developing and adult olfactory (antennal) lobe of the moth Manduca sexta. Early in development, glial cells occupy discrete regions of the developing olfactory pathway and processes of γ‐aminobutyric acid (GABA)ergic neurons extend into some of these regions. Because GABA is known to have developmental effects in a variety of systems, we explored the possibility that the glial cells express a GABA transporter that could regulate GABA levels to which olfactory neurons and glial cells are exposed. By using an antibody raised against a characterized high‐affinity M. sexta GABA transporter with high sequence homology to known mammalian GABA transporters (Mbungu et al. [1995] Arch. Biochem. Biophys. 318:489–497; Umesh and Gill [2002] J. Comp. Neurol. 448:388–398), we found that the GABA transporter is localized to subsets of centrally derived glial cells during metamorphic adult development. The transporter persists into adulthood in a subset of the neuropil‐associated glial cells, but its distribution pattern as determined by light‐and electron‐microscopic‐level immunocytochemistry indicates that it could not serve to regulate GABA concentration in the synaptic cleft. Instead, its role is more likely to regulate extracellular GABA levels within the glomerular neuropil. Expression in the sorting zone glial cells disappears after the period of olfactory receptor axon ingrowth, but may be important during ingrowth if GABA regulates axon growth. Glial cells take up GABA, and that uptake can be blocked by L‐2,4‐diaminobutyric acid (DABA). This is the first molecular evidence that the central glial cell population in this pathway is heterogeneous. J. Comp. Neurol. 518:815–838, 2010. © 2009 Wiley‐Liss, Inc.
Different Catalytic Effects of a Single Water Molecule: The Gas‐Phase Reaction of Formic Acid with Hydroxyl Radical in Water Vapor
Authors: Anglada Josep M. , Gonzalez Javier
Published: October 2009

The effect of a single water molecule on the reaction mechanism of the gas‐phase reaction between formic acid and the hydroxyl radical was investigated with high‐level quantum mechanical calculations using DFT–B3LYP, MP2 and CCSD(T) theoretical approaches in concert with the 6‐311+G(2df,2p) and aug‐cc‐pVTZ basis sets. The reaction between HCOOH and HO has a very complex mechanism involving a proton‐coupled electron transfer process (pcet), two hydrogen‐atom transfer reactions (hat) and a double proton transfer process (dpt). The hydroxyl radical predominantly abstracts the acidic hydrogen of formic acid through a pcet mechanism. A single water molecule affects each one of these reaction mechanisms in different ways, depending on the way the water interacts. Very interesting is also the fact that our calculations predict that the participation of a single water molecule results in the abstraction of the formyl hydrogen of formic acid through a hydrogen atom transfer process (hat).
Structural Features of Interacting Complementary Liposomes Promoting Formation of Multicompartment Structures
Authors: Sideratou Zili , Sterioti Nikoletta , Tsiourvas Dimitris , Paleos Constantinos M.
Published: October 2009

The structural features of complementary liposomes and factors favoring formation of multicompartment systems are investigated. Specifically, liposomal formulations consisting of PEGylated unilamellar liposomes with guanidinium moieties located at the distal end of polyethylene glycol (PEG) chains interact with complementary multilamellar liposomes bearing phosphate moieties. Furthermore, the number of PEG chains attached to the unilamellar interface of the liposomes is enhanced by incorporating PEGylated cholesterol in their bilayer. While molecular recognition of the liposomes is the driving force for initiating multicompartmentalization, it is the enhanced PEGylation at the liposomal interface that synergistically promotes fusion resulting in large and well‐formed multicompartment systems. A mechanism is proposed according to which initial adhesion of the liposomes, followed by reorganization of their membrane lipids, leads to giant bilayer aggregates incorporating large liposomes.
QoS‐aware fair packet scheduling in IEEE 802.16 wireless mesh networks
Authors: Li Yajun , Yang Yuhang , Zhou Liang , Wei Anne , Cao Chengyu
Published: October 2009

In this paper, we address the problem of heterogeneous quality‐of‐service (QoS) provisioning in IEEE 802.16‐based wireless mesh networks. Our objective is to provide a novel service differentiation scheme based on distributed scheduling in the IEEE 802.16‐based mesh mode, thereby offering QoS guarantees. We first devise a novel scheme for the traffic class differentiation, which can be implemented at the medium access control layer. We then present a QoS‐aware fair packet scheduling (QFPS) algorithm to fulfill the QoS provisioning. With QFPS, a traffic flow with urgent QoS demand is guaranteed to be given priority in wireless resource allocation over those ones with mild QoS requirements. A shorter end‐to‐end delay is therefore expected to be offered for the traffic flows with time‐urgent requirements. Moreover, we propose a new fairness model among different traffic flows traversing the same node. All traffic flows passing through a node are served by the Deficit Round‐Robin scheduling algorithm to achieve fairness within the same priority group. The experimental results of the QFPS demonstrate that various traffic flows are provided with a differentiated service that offers QoS guarantees. Copyright © 2009 John Wiley & Sons, Ltd.
A Probasin‐MerCreMer BAC allows inducible recombination in the mouse prostate
Authors: Birbach Andreas , Casanova Emilio , Schmid Johannes A.
Published: October 2009

Tissue‐specific transgene expression in the prostate epithelium has previously been achieved using short prostate‐specific promoters, rendering transgenic mouse lines susceptible to integration site‐dependent effects. Here we demonstrate the applicability of bacterial artificial chromosome (BAC) technology to transgene expression in the prostate epithelium. We present mouse lines expressing an inducible Cre protein (MerCreMer) under the control of regulatory elements of the probasin gene on a BAC. These mouse lines show high organ specificity, high transgene expression in anterior, dorsal and lateral prostate lobes, no background Cre recombination using a reporter strain and adjustable amounts of Cre‐induced recombination upon tamoxifen induction. Together with two recently reported transgenic lines expressing the Cre‐ERT2 protein from small prostate‐specific promoters, these mouse lines will be useful in research focused on prostate‐specific disorders such as benign hyperplasia or cancer. genesis 47:757–764, 2009. © 2009 Wiley‐Liss, Inc.
Oligodendroglial and pan‐neural crest expression of Cre recombinase directed by Sox10 enhancer
Authors: Stine Zachary E. , Huynh Jimmy L. , Loftus Stacie K. , Gorkin David U. , Salmasi Amirali H. , Novak Thomas , Purves Todd , Miller Ronald A. , Antonellis Anthony , Gearhart John P. , Pavan William J. , McCallion Andrew S.
Published: October 2009

Utilizing a recently identified Sox10 distal enhancer directing Cre expression, we report S4F:Cre, a transgenic mouse line capable of inducing recombination in oligodendroglia and all examined neural crest derived tissues. Assayed using R26R:LacZ reporter mice expression was detected in neural crest derived tissues including the forming facial skeleton, dorsal root ganglia, sympathetic ganglia, enteric nervous system, aortae, and melanoblasts, consistent with Sox10 expression. LacZ reporter expression was also detected in non‐neural crest derived tissues including the oligodendrocytes and the ventral neural tube. This line provides appreciable differences in Cre expression pattern from other transgenic mouse lines that mark neural crest populations, including additional populations defined by the expression of other SoxE proteins. The S4F:Cre transgenic line will thus serve as a powerful tool for lineage tracing, gene function characterization, and genome manipulation in these populations. genesis 47:765–770, 2009. © 2009 Wiley‐Liss, Inc.
Generation and analysis of a mouse line harboring GFP in the Eomes/Tbr2 locus
Authors: Arnold Sebastian J. , Sugnaseelan Jacintha , Groszer Matthias , Srinivas Shankar , Robertson Elizabeth J.
Published: October 2009

During mouse embryonic development, the T‐box transcription factor Eomes/Tbr2 is expressed in highly dynamic patterns in various progenitor cell types. Those include the undifferentiated cells of the trophectoderm, ingressing nascent mesoderm at the primitive streak, and intermediate progenitor cells of the developing cerebral cortex. We generated an EomesGFP‐ targeted allele to follow the highly dynamic patterns of Eomes expression and to allow for the identification of novel expression domains. We show that our novel allele recapitulates endogenous gene expression at known sites of expression and confirm our results by anti‐Eomes immunofluorescent staining. Using this novel allele we were able to identify previously undocumented domains of Eomes expression within the visceral endoderm and at various locations in the developing and adult mouse brain. genesis 47:775–781, 2009. © 2009 Wiley‐Liss, Inc.
Placenta‐specific gene activation and inactivation using integrase‐defective lentiviral vectors with the Cre/LoxP system
Authors: Morioka Yuka , Isotani Ayako , Oshima Robert G. , Okabe Masaru , Ikawa Masahito
Published: October 2009

Transgenic and knockout studies have advanced our understanding of the genetic control of embryonic development over the past decades. However, interpretation of the phenotype of mutant mice is potentially complicated, since the commonly used knockout approach modifies both the fetal and placental genome. To circumvent this problem, we previously developed a placenta‐specific gene manipulation system by lentiviral vector transduction of embryos at the blastocyst stage. In the present study, by combination with the Cre/LoxP system, we successfully demonstrate placenta‐specific gene activation and inactivation in EGFP reporter mice and Ets2 floxed mice, respectively. Transient expression using integrase‐defective lentiviral (IDLV) vectors diminished the toxic effect of Cre expression and solved the dilemma of mosaic recombination with lower concentrations and toxic effects with higher concentrations of Cre recombinase. We also show that placenta‐specific Ets2 disruption causes embryonic lethality and reconfirmed the critical role of Ets2 during placentation. This technology facilitates both gain and loss of gene function analyses in placental development during pregnancy. Since IDLV vectors can efficiently transduce a variety of cell types similarly to wild‐type vectors, our IDLV‐Cre strategy is potentially useful for a wide range of applications. genesis 47:793–798, 2009. © 2009 Wiley‐Liss, Inc.
Generation of an allele to inactivate Wnt4 gene function conditionally in the mouse
Authors: Shan Jingdong , Jokela Tiina , Peltoketo Hellevi , Vainio Seppo
Published: October 2009

The Wnt family member Wnt4 is critical for the development of several organs, including the kidney, gonad, and adrenal, mammary, and pituitary glands. To study its potential postnatal functions, we generated a floxed Wnt4 allele. A single loxP site was targeted to the second intron, while a loxP‐Neo‐loxP cassette was placed 3′ from Exon 5. The floxed Neo cassette was subsequently removed by crossing with MeuCre40 transgenic mice. The Wnt4 gene was specifically inactivated with CAGCre and another Wnt4 allele, Wnt4EGFPCre, in which the Cre is driven by the endogenous Wnt4 promoter. Deletion of Wnt4 gene function with CAGCre impaired kidney development, as is the case with the conventional knockout. Similarly, the Wnt4EGFPCre‐mediated inactivation of Wnt4 function considerably reduced the amount of Wnt4 transcripts, led to a severe defect in kidney development, and caused the female embryos to undergo partial sex reversal to males. All in all, the floxed Wnt4 allele serves as a useful tool for studying the roles of Wnt4 signaling during the life cycle. genesis 47:782–788, 2009. © 2009 Wiley‐Liss, Inc.
Regulation of NK cell trafficking by CD81
Authors: Krämer Benjamin , Schulte Daniela , Körner Christian , Zwank Claudia , Hartmann Agathe , Michalk Monika , Söhne Jennifer , Langhans Bettina , Nischalke Hans‐Dieter , Coenen Martin , Möhl Christoph , Vogt Annabelle , Hennenberg Martin , Sauerbruch Tilman , Spengler Ulrich , Nattermann Jacob
Published: October 2009

NK cells, a heterogeneous sub‐population of lymphocytes, are critically involved in the regulation of both innate and adaptive immune responses in humans. Besides their participation in the control of tumors and viral infections, they also regulate inflammatory processes, mediating both beneficial and detrimental effects. To effectively fulfil their role in immune surveillance, proper trafficking of NK cells is essential. However, the mechanisms and factors governing NK cell recruitment are only poorly dissected. Here, we describe the functional role of tetraspanins, a family of evolutionary conserved cell‐surface proteins, in modulating migration and transmigration of human NK cells. We demonstrate expression of various tetraspanins on NK cells. Furthermore, we show that stimulation of the NK cell‐expressed tetraspanin CD81 induces phosphorylation of ezrin/radixin/moesin proteins and leads to NK cell polarization thereby facilitating NK cell migration toward various chemokines/cytokines. Finally, we provide evidence for a role of CD81 in promoting adhesion of NK cells to components of the extracellular matrix, a prerequisite for extravasation of lymphocytes in inflamed tissues. Thus, our data suggest that the tetraspanin CD81 is importantly involved in the regulation of NK cell recruitment.
ERK/p38 MAP‐kinases and PI3K are involved in the differential regulation of B7‐H1 expression in DC subsets
Authors: Karakhanova Svetlana , Meisel Stefan , Ring Sabine , Mahnke Karsten , Enk Alexander H.
Published: October 2009

Regulatory molecules of the B7‐H‐family expressed by DC are important for immune homeostasis, but their regulation is largely unknown. When investigating the pathways regulating B7‐H1 expression in monocyte‐derived DC (MoDC), freshly isolated myeloid DC (mDC) and plasmacytoid DC, respectively, we showed that in MoDC and mDC B7‐H1 expression was upregulated by a standard cytokine cocktail, poly I:C or LPS. MoDC utilize ERK and PI3K pathways to upregulate B7‐H1 in response to cytokines, whereas p38 kinase was predominantly utilized in response to poly I:C. In mDC, ERK and p38 pathways are involved in B7‐H1 regulation, and similar to MoDC, mainly p38 signaling was required for poly I:C‐induced expression of B7‐H1. Plasmacytoid DC responded only to CpG with upregulation of B7‐H1 and in addition to p38 also utilized the PI3K and ERK pathways to regulate B7‐H1 expression. As a functional consequence of B7‐H1 expression on DC, we demonstrate downmodulation of IFN‐γ production in T cells. Thus, the differential regulation of B7‐H1 on DC subsets may suppress immune responses variably, depending on the target DC population. Further analysis of the regulatory mechanisms may facilitate the development of new immunosuppressive therapies, utilizing the regulation of B7‐H1 expression on DC.
CpG‐enhanced CD8+ T‐cell responses to peptide immunization are severely inhibited by B cells
Authors: Overstreet Michael G. , Freyberger Helen , Cockburn Ian A. , Chen Yun‐Chi , Tse Sze‐Wah , Zavala Fidel
Published: October 2009

Synthetic peptides encoding protective pathogen‐derived epitopes represent – in principle – an ideal approach to T‐cell vaccination. Empirically, however, these strategies have not been successful. In the current study, we profiled the early activation of CD8+ T cells by MHC class I‐restricted peptide immunization to better understand the biology of this response. We found that CD8+ T cells proliferated robustly in response to low doses of short synthetic peptides in PBS, but failed to acquire effector function or form memory populations in the absence of the TLR ligand CpG. CpG was unique among TLR ligands in its ability to enhance the response to peptide and its adjuvant effects had strict temporal requirements. Interestingly, CpG treatment modulated T‐cell expression of the surface receptors PD‐1 and CD25, providing insight into its possible adjuvant mechanism. The effects of CpG on peptide immunization were dramatically enhanced in the absence of B cells, demonstrating a unique system of regulation of T‐cell responses by these lymphocytes. The results reported here provide insight into the complex response to a simple vaccination regimen, as well as a framework for a rational peptide‐based vaccine design to both exploit and overcome targeted aspects of the immune response.
Antigen‐specific Treg regulate Th17‐mediated lung neutrophilic inflammation, B‐cell recruitment and polymeric IgA and IgM levels in the airways
Authors: Jaffar Zeina , Ferrini Maria E. , Girtsman Teri A. , Roberts Kevan
Published: October 2009

Th17 cells play key roles in mediating autoimmunity, inflammation and mucosal host defense against pathogens. To determine whether naturally occurring Treg (nTreg) limit Th17‐mediated pulmonary inflammation, OVA‐specific CD4+ Th17 cells and expanded CD4+CD25+Foxp3+ nTreg were cotransferred into BALB/c mice that were then exposed to OVA aerosols. Th17 cells, when transferred alone, accumulated in the lungs and posterior mediastinal LN and evoked a pronounced airway hyperreactivity and neutrophilic inflammation, characterized by B‐cell recruitment and elevated IgA and IgM levels. Cotransfer of antigen‐specific nTreg markedly reduced the Th17‐induced pulmonary inflammation and associated neutrophilia, B‐cell influx and polymeric Ig levels in the airways, but did not inhibit airway hyperreactivity. Moreover, the regulation appeared restricted to the site of mucosal inflammation, since transfer of nTreg did not affect the Th17 response developing in the lung draining LN, as evidenced by unaltered levels of IL‐17 production and low numbers of Foxp3+ Treg. Our findings suggest a crucial role for Th17 cells in mediating airway B‐cell influx and IgA response, and demonstrate that antigen‐specific nTreg suppress Th17‐mediated lung inflammation. These results provide new insights into how Th17 responses are limited and may facilitate development of novel approaches for controlling Th17‐induced inflammation.
Modulation of pulmonary DC function by vaccine‐encoded GM‐CSF enhances protective immunity against Mycobacterium tuberculosis infection
Authors: Nambiar Jonathan K. , Ryan Anthony A. , U. Kong Carlyn , Britton Warwick J. , Triccas James A.
Published: October 2009

The rational design of new vaccines engineered to target key components of the host immune response is crucial to aid control of important infectious diseases such as tuberculosis. In this report, we determined whether modifying the function of pulmonary APC could improve protection against infection with Mycobacterium tuberculosis. Targeted delivery to the lung of the cytokine GM‐CSF, expressed by the Mycobacterium bovis BCG vaccine strain, increased pulmonary DC numbers and secretion of the immunoregulatory cytokine IL‐12, compared with parental BCG immunization. This impact on APC number by BCG:GM‐CSF resulted in accelerated priming of antigen‐specific CD4+ T cells in the mediastinal lymph nodes and increased migration of activated CD4+ T cells into the lung. i.n. administration of BCG:GM‐CSF resulted in significantly increased protection against M. tuberculosis infection compared with mice vaccinated with BCG alone. BCG:GM‐CSF exhibited an improved safety profile, as immunodeficient RAG1−/− mice vaccinated i.n. with BCG:GM‐CSF survived significantly longer than control BCG‐vaccinated mice. These data demonstrate that manipulating immune cells in the lung by BCG‐based delivery of GM‐CSF can assist the development of protective mucosal immunity against pulmonary bacterial infection.
IL‐24 protects against Salmonella typhimurium infection by stimulating early neutrophil Th1 cytokine production, which in turn activates CD8+ T cells
Authors: Ma Yunfeng , Chen Haidan , Wang Qilong , Luo Fengling , Yan Jun , Zhang Xiao‐Lian
Published: October 2009

Salmonella are important intracellular pathogens in humans and other animal hosts. IL‐24 is a novel tumour suppressor and can mediate induction of Th1‐type cytokines from PBMC. However, the immunological consequences of this cytokine during intracellular pathogen infection in vivo remain unclear. In the present study, we used a virulent S. typhimurium C5 infected mouse model of typhoid fever to demonstrate that administration of exogenous IL‐24 had a protective effect against the bacteria. The IL‐24 glycosylation site mutant, in contrast, showed a decreased protective effect. Furthermore, the protective effect of IL‐24 was abrogated in IFN‐γ KO mice. More importantly, we demonstrated that IL‐24 predominately stimulated neutrophils to produce IFN‐γ and IL‐12, subsequently activating CD8+ T cells both in vivo and in vitro. In addition, IL‐24 could induce neutrophils to produce NO. These data indicate that the neutrophils activated by IL‐24 may play important roles in host defence against Salmonella infection in vivo. Our findings support the development of a novel cytokine immunotherapy against Salmonella.
Soluble HLA‐I‐mediated secretion of TGF‐β1 by human NK cells and consequent down‐regulation of anti‐tumor cytolytic activity
Authors: Ghio Massimo , Contini Paola , Negrini Simone , Boero Silvia , Musso Alessandra , Poggi Alessandro
Published: October 2009

Soluble HLA class I (sHLA‐I) molecules can regulate survival of NK cells and their anti‐tumor killing activity. Herein, we have analysed whether interaction of sHLA‐I with CD8 and/or different isoforms of killer Ig‐like receptors (KIR) induced secretion of transforming growth factor (TGF)‐β1. CD8+KIR− NK cell clones secreted TGF‐β1 upon the interaction of sHLA‐I with CD8 molecule. sHLA‐Cw4 or sHLA‐Cw3 alleles engaging inhibitory isoforms of KIR, namely KIR2DL1 or KIR2DL2, strongly downregulated TGF‐β1 production elicited through CD8. On the other hand, sHLA‐Cw4 or sHLA‐Cw3 alleles induced secretion of TGF‐β1 by ligation of stimulatory KIR2DS1 or KIR2DS2 isoforms. TGF‐β1 strongly reduced NK cell‐mediated tumor cell lysis and production of pro‐inflammatory cytokines such as TNF‐α and IFN‐γ. Also, TGF‐β1 inhibited NK cell cytolysis induced by the engagement of stimulatory receptors including NKG2D, DNAM1, 2B4, CD69, NKp30, NKp44 and NKp46. The IL‐2‐dependent surface upregulation of some of these receptors was prevented by TGF‐β1. Furthermore, TGF‐β1 hampered IL‐2‐induced NK cell proliferation but not IL‐2‐mediated rescue from apoptosis of NK cells. Depletion of TGF‐β1 restored all the NK cell‐mediated functional activities analysed. Taken together these findings suggest that sHLA‐I antigens may downregulate the NK cell‐mediated innate response by inducing TGF‐β1 release.
NKT cells: Friend or foe during viral infections?
Authors: Diana Julien , Lehuen Agnès
Published: October 2009

NKT cells are innate‐like T lymphocytes that are found in rodents and primates. They are non‐conventional T cells restricted by the CD1d molecule that presents self and exogenous glycolipids. NKT cells are unique in their ability to promptly secrete copious amounts of cytokines such as IFN‐γ and IL‐4. Once activated, NKT cells can provide maturation signals to downstream cells, including DC, NK cells, and lymphocytes, thereby contributing to both innate and acquired immunity. Accordingly, NKT cells can influence a wide array of immune responses, including tumor surveillance, maintenance of self‐tolerance and anti‐infectious defenses. Studies performed with NKT‐cell‐deficient mice have shown that these cells are critical for the clearance of various pathogens. During bacterial infections, NKT cells can be activated either indirectly by DC or directly by bacterial lipid antigens presented by CD1d. Although viruses do not contain lipid antigens, NKT cells have also been implicated in antiviral responses. The capacity of NKT cells to regulate viral immune‐surveillance, either constitutively or post‐activation, makes them an attractive clinical target. In this review, we summarize recent publications dealing with the functions and relevance of NKT cells in the context of viral infections, both in murine models and in humans.
Metal‐Hydride Bonding in Higher Alkali Metal Boron Monohydrides
Authors: Haywood Joanna , Wheatley Andrew E. H.
Published: October 2009

The recent demonstration that hydride translocation involving alkali metal boron monohydrides can be utilised to trap hydride in metal clusters has led to investigation of the alkali metal salts of triethylborohydride, [Et3BH]–. Treatment of Et3BHM (M = Li, Na, K) with the polydentate donors (L) N,N,N′,N′‐tetramethylethylenediamine (TMEDA) and N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) is reported. For M = Li, L = TMEDA ion separation is noted, with the metal ion encapsulated by two donor ligands. In contrast, for M = Na, K the TMEDA‐solvates reveal hydride‐bridged centro‐symmetric dimers based on M2H2‐metallocyclic cores. X‐ray diffraction reveals mean Na–H and K–H distances of 2.29 and 2.55 Å, respectively. For M = K, the PMDETA‐solvate is also reported, with the hydride‐bridged dimer motif being retained, with an expanded mean metal–hydride distance of 2.67 Å. Solution data and 1JBH coupling constants are reported in both polar and non‐polar solvents.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Specific Ca2+ Fluorescent Sensor: Signaling by Conformationally Induced PET Suppression in a Bichromophoric Acridinedione
Authors: Ashokkumar Pichandi , Ramakrishnan Vayalakkavoor T. , Ramamurthy Perumal
Published: October 2009

A series of acridinedione‐based bichromophoric podand systems 1a–c were synthesized and characterized. Among these, bichromophore 1c shows specific binding of Ca2+ in the presence of other biologically important metal ions like Na+, K+, Mg2+, and Zn2+. The selective complexation was proved by steady‐state emission, time‐resolved emission, and 1H NMR titration. Signaling of the binding event was achieved by Ca2+‐induced folding of the bichromophore, resulting in PET suppression in the acridinedione chromophore. Involvement of a PET process in the optical signaling was confirmed by comparing bichromophores 1a–c with non‐PET compound 2 and monochromophore model compound 3. Non‐PET compound 2 failed to give optical response upon Ca2+ binding as a result of the absence of a PET process in the Ca2+‐bound complex. Monochromophore 3 shows a similar optical response, which is the same as that in 1c. Titration of the metal‐ion‐bound complex of 1c with EDTA released the metal ion from the complex, thereby regaining the original photophysical properties of the bichromophore.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Dehydro‐β‐amino Acid Containing Peptides as Promising Sequences for Drug Development
Authors: Cardillo Giuliana , Gennari Arianna , Gentilucci Luca , Mosconi Elisa , Tolomelli Alessandra , Troisi Stefano
Published: October 2009

In the course of a program devoted to the synthesis of small peptidic molecules mimicking the RGD (Arg‐Gly‐Asp) motif, the allylic amination of enantiomerically pure carbonates with 4‐substituted benzylamines afforded dehydro‐β‐amino esters through an SN2′ mechanism. The reaction performed with 4‐aminobenzylamine occurred with complete chemoselectivity, as the aliphatic amine was much more reactive than the aromatic one. This allowed useful precursors of biologically active compounds to be obtained, avoiding extra protection–deprotection steps. The same reaction performed on glycine‐derived amides gave similar results, allowing a novel type of RGD mimetic to be prepared, whose ability to inhibit cell adhesion was found to be very promising.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Electroanalysis of Bisphenol A at a Multiwalled Carbon Nanotubes‐gold Nanoparticles Modified Glassy Carbon Electrode
Authors: Tu Xinman , Yan Liushui , Luo Xubiao , Luo Shenglian , Xie Qingji
Published: October 2009

A sensitive electrochemical method was developed for the determination of bisphenol A (BPA) at a glassy carbon electrode (GCE) modified with a multiwalled carbon nanotubes (MWCNTs)‐gold nanoparticles (GNPs) hybrid film, which was prepared based on the electrostatic interaction between positively charged cetyltrimethylammonium bromide (CTAB) and negatively charged MWCNTs and GNPs. The MWCNT‐GNPs/GCE exhibited an enhanced electroactivity for BPA oxidation versus unmodified GCE and MWCNTs/GCE. The experimental parameters, including the amounts of modified MWCNTs and GNPs, the pH of the supporting electrolyte, scan rate and accumulation time, were examined and optimized. Under the optimal conditions, the differential pulse voltammetric anodic peak current of BPA was linear with the BPA concentration from 2.0×10−8 to 2×10−5 mol L−1, with a limit of detection of 7.5 nmol L−1. The proposed procedure was applied to determine BPA leached from real plastic samples with satisfactory results.
Novel device for quick measurement of glucose in POCT areas without pre‐analytical steps based on a multi‐way glucose biosensor
Authors: Zahn Dorothea , Szeponik Jan , Gandhi Adrian
Published: October 2009

Professional Point of Care testing demands rapid analysis and professional quality. To assure rapid analysis of high quality the analytical tool ideally should be able to work without sample pre‐treatment and should offer the opportunity to calibrate and/or control the analytical performance of the tool. In contrast to an enormous number of different disposable‐strips used for patient self monitoring today and based on an extended knowledge with respect to multi‐way biosensors used in laboratory analyzers we decided to develop a professional Point of Care Testing system for glucose analysis based on a multi‐way biosensor. The multi‐way glucose biosensor placed in the instrument for 30 days did reduce the lag time between blood withdrawal and availability of a result of lab quality in a bedside area to about 10 seconds. No pre‐analytical steps are necessary for measuring capillary whole blood, no crossing over was observed, and the data could be transferred into a laboratory information system or a hospital information system. Thus, we were able to realize tools for professional health control able to measure glucose values in laboratory quality at places outside laboratories: e.g., in doctor's offices, hospital wards, critical care units, and training units of athletes. By combining the advantages of laboratory analyzers (high quality and low sample price) and the advantages of disposable strips (simple procedure and immediate results after sample withdrawal) with the Glukometer 3000 and LactatProfi 3000 we did start to fill the gap between the two basic technologies available on the market for diagnosis today. Glukometer 3000 and LactatProfi 3000 are worldwide the first and only mobile glucose and lactate measuring instruments for decentralized locations based on multi‐way biosensors.