bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conditional tamoxifen Cre induced mutagenesis in the embryonic kidney in organ culture
Authors: Jokela Tiina , Vainio Seppo 
Published: December 2007

AbstractDevelopmental control genes are often sequentially and repeatedly functional during embryogenesis, and for this reason conditional mutagenesis tools are often required to study their roles in detail. Cre recombinase fused to the modified estrogen hormone‐binding domain (ERTm) generates a Cre in which the recombination activity of the LoxP‐containing gene can be regulated by the nonsteroidal estrogen analogue 4‐hydroxytamoxifen (4OH‐TM). ERTm may provide a useful way of achieving conditional mutagenesis in conjunction with the classic organ culture methods of experimental embryology. We used embryonic kidneys separated from the Cre‐ERTm; R26R embryos to assay whether efficient 4OH‐TM‐inducible genomic recombination can be achieved in organ culture and in experimentally induced kidney mesenchymes. Our results indicate that the inducible ERTm Cre/loxP system indeed provides an effective way of conditionally mutagenizing genes in kidney organ culture and tissue conjugates. genesis 45:757–761, 2007. © 2007 Wiley‐Liss, Inc.
Generation of mice harboring a Sox4 conditional null allele
Authors: Penzo‐Méndez Alfredo , Dy Peter , Pallavi Bhattaram , Lefebvre Véronique 
Published: December 2007

AbstractSox4 belongs to the family of Sry‐related HMG box transcription factors, which specify cell fate and differentiation in many lineages. Sox4 is widely expressed in the embryo and controls such processes as neuronal tissue, lymphocyte, heart, and bone development. Sox4‐null mice die at embryonic day 14 from heart malformation. This early lethality has therefore limited studies on Sox4 functions. We show here that we have generated mice harboring a Sox4 conditional null allele (Sox4fl+) by flanking the entire coding region with loxP sites. Sox4fl+/fl+ mice are indistinguishable from wildtype mice and produce the wildtype Sox4 protein at a normal level. Sox4fl+ is efficiently converted into a null allele (Sox4fl−) by Cre recombinase in somatic and germ‐line cells, and Sox4fl−/fl− embryos die from the same heart defects as Sox4−/− mice. This Sox4 conditional null allele will thus be a valuable tool to further uncovering Sox4 functions in various processes in vivo. genesis 45:776–780, 2007. © 2007 Wiley‐Liss, Inc.
Establishment of conditional knockout alleles for the gene encoding the regulator of telomere length (RTEL)
Authors: Wu Xiaoli , Sandhu Sumit , Ding Hao 
Published: December 2007

AbstractRegulator of telomere length (RTEL) is a DNA helicase‐like protein that has recently been demonstrated to be required for the maintenance of telomere length and genomic stability. Rtel null mice are embryonic lethal with the defects in the nervous system, the heart, the vasculature, and extra‐embryonic tissues. Rtel could also be important for the postnatal development as its expression is strongly induced in the proliferating adult cells. To further characterize the role of RTEL in adult tissue function and homeostasis, we have generated the floxed (loxP‐flanked) alleles allowing to inactivate RTEL through Cre‐mediated recombination in a cell‐ or tissue‐specific manner and also to circumvent the embryonic lethality of the Rtel null allele. Mice heterozygous or homozygous for these alleles are viable and fertile. Crossing the floxed Rtel allele with a ubiquitous Cre transgenic line resulted in embryonic defects identical to those previously described for the Rtel null embryos. These conditional alleles will therefore be the important genetic tools for dissecting the spatial and temporal roles of RTEL in the regulation of telomere length and genomic stability during postnatal development and tumorigenesis. genesis 45:788–792, 2007. © 2007 Wiley‐Liss, Inc.
Synthesis of Novel Derivatives of (1S,4S)‐2,5‐Diazabicyclo[2.2.1]heptane and Their Evaluation as Potential Ligands in Asymmetric Catalysis
Authors: Melgar‐Fernández Roberto , González‐Olvera Rodrigo , Olivares‐Romero J. Luis , González‐López Vianney , Romero‐Ponce Leticia , del Refugio Ramírez‐Zárate María , Demare Patricia , Regla Ignacio , Juaristi Eusebio 
Published: December 2007

AbstractThirty‐seven (most of them novel) chiral derivatives of (1S,4S)‐2,5‐diazabicyclo[2.2.1]heptane (2–36, 38, 39) were prepared from (S)‐trans‐4‐hydroxyproline. A selection of these chiral ligands were examined as potential ligands in the preparation of catalysts for the enantioselective addition of diethylzinc to aldehydes and as chiral Lewis acid activators in the asymmetric Diels–Alder reaction. In the former system, diamine 30 induced up to 92 % enantiomeric excess in the formation of (S)‐phenyl ethyl carbinol, whereas in the case of the cycloaddition reaction between cyclopentadiene and 3‐acryloyloxazolidin‐2‐one the catalytic complex formed between dimeric derivative 8 and copper triflate [Cu(OTf)2] afforded the expected product in a 95:5 endo/exo ratio and up to 72 % ee for the major diastereomeric product. Finally, some of the novel chiral diamines prepared in this work were also evaluated as potential organocatalysts in the asymmetric amination of ethyl α‐phenyl‐α‐cyano acetate. Bifunctional derivative 12 provided the aminated product in excellent yield and with up to 40 % ee.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Quantitative structure–mobility relationship study of a diverse set of organic acids using classification and regression trees and adaptive neuro‐fuzzy inference systems
Authors: Jalali‐Heravi Mehdi , Shahbazikhah Parviz 
Published: December 2007

AbstractA quantitative structure–mobility relationship was developed to accurately predict the electrophoretic mobility of organic acids. The absolute electrophoretic mobilities (μ0) of a diverse dataset consisting of 115 carboxylic and sulfonic acids were investigated. A set of 1195 zero‐ to three‐dimensional descriptors representing various structural characteristics was calculated for each molecule in the dataset. Classification and regression trees were successfully used as a descriptor selection method. Four descriptors were selected and used as inputs for adaptive neuro‐fuzzy inference system. The root mean square errors for the calibration and prediction sets are 1.61 and 2.27, respectively, compared with 3.60 and 3.93, obtained from a previous mechanistic model.
Electrophoretic field gradient focusing: An investigation of the experimental parameters
Authors: Tuñón Pilar González , Wang Yating , Myers Peter , Bartle Keith D. , Bowhill Larry , Ivory Cornelius F. , Ansell Richard J. 
Published: December 2007

AbstractElectrophoretic field gradient focusing has been used to separate the two oxidation states of myoglobin (Mb), and to separate Mb from bromophenol blue (BPB). Polyacrylamide and Sephadex were shown to be suitable packing materials whilst silica led to band broadening with Mb. BPB and Mb could be simultaneously focused apart using either a fixed 21‐electrode setup or a dynamic 6‐electrode setup. Using a dynamic three‐electrode setup either analyte could be focused but not both simultaneously. It was shown that a higher ionic strength buffer in the separation channel compared to the coolant channel enhanced focusing between electrodes due to a conductivity gradient. Different running buffers were investigated and it was found that using a pH 8.6 buffer containing N,N,N‐tris(hydroxymethyl)aminomethane (Tris) and phosphate ions the oxidation states of Mb could be separated but the separation of Mb from BPB was not as good as would be hoped for. Using a pH 8.6 buffer containing Tris, N‐2‐hydroxyethylpiperazine‐N′‐3‐propanesulphonate and chloride ions as running buffer, BPB and Mb could be well separated but the two oxidation states of Mb merged.
Copper impregnated mesoporous activated carbon as a high efficient catalyst for the complete destruction of pathogens in water
Authors: Kennedy L. John , Kumar A. Ganesh , Ravindran B. , Sekaran G. 
Published: December 2007

AbstractCopper impregnated mesoporous activated carbon catalyst was applied for the elimination of microorganisms in wastewater. The antibacterial activity of the catalyst was determined qualitatively by testing the removal of pathogens in water after contacting with the catalyst. Escherichia coli, Shigella flexneri, Shigella dysenteriae, Shigella sonnei, and Salmonella typhi were taken as the model pathogens in determining the antimicrobial activity of the catalyst. The catalyst developed for this purpose was thoroughly characterized using instrumental techniques such as BET analysis, X‐ray diffraction, FTIR spectroscopy, and scanning electron microscope to determine the pore and surface area, structural phases, surface functional groups, and surface morphology respectively. The energy dispersive X‐ray analysis carried out confirmed qualitatively the percentage of copper impregnated in the catalyst. The experimental studies revealed that the catalyst was highly efficient and advantageous to be employed for industrial applications because of the nonleacheablity of copper from the catalyst and nonreoccurrence of the pathogens in the treated water. The transmission electron microscopy evidenced the complete cell wall rupture of the microorganisms. All the experimental results revealed that the copper impregnated mesoporous activated carbon exhibited a strong and long term antibacterial activity throughout the studies for repeated cycles. © 2007 American Institute of Chemical Engineers Environ Prog, 2008
Mineral chemistry, crystallization conditions and magma mixing‐mingling at Orduzu volcano (Malatya), Eastern Anatolia, Turkey
Authors: Önal A. 
Published: December 2007

AbstractThe Middle Miocene Orduzu volcanic suite, which is a part of the widespread Neogene Yamadağ volcanism of Eastern Anatolia, consists of a rhyolitic lava flow, rhyolitic dykes, a trachyandesitic lava flow and basaltic trachyandesitic dykes. Existence of mafic enclaves and globules in some of the volcanic rocks, and microtextures in phenocrysts indicate that magma mingling and mixing between andesitic and basaltic melts played an important role in the evolution of the volcanic suite. Major and trace element characteristics of the volcanic rocks are similar to those formed in convergent margin settings. In particular, incompatible trace element patterns exhibit large depletions in high field strength elements (Nb and Ta) and strong enrichments in both large ion lithofile elements (Ba, Th and U) and light rare earth elements, indicating a strong subduction signature in the source of the volcanic rocks. Furthermore, petrochemical data obtained suggest that parental magmas of rhyolite lava and dykes, and trachyandesite lava and basaltic trachyandesite dykes were derived from subduction‐related enriched lithospheric mantle and metasomatized mantle (± asthenosphere), respectively. A detailed mineralogical study of the volcanic suite shows that plagioclase is the principal phenocryst phase in all of the rock units from the Orduzu volcano. The plagioclase phenocrysts are accompanied by quartz in the rhyolitic lava flows and by two pyroxenes in the trachyandesitic lava flows and basaltic trachyandesitic dykes. Oxide phases in all rocks are magnetite and ilmenite. Calculated crystallization temperatures range from 650°C to 800°C for plagioclase, 745°C–1054°C for biotite, 888°C–915°C for pyroxene and 736°C–841°C for magnetite–ilmenite pairs. Calculated crystallization pressures of pyroxenes vary between 1.24–5.81 kb, and oxygen fugacity range from −14.47 to −12.39. The estimates of magmatic intensive parameters indicate that the initial magma forming the Orduzu volcanic unit began to crystallize in a high‐level magma chamber and then was stored in a shallow reservoir where it underwent intermediate‐mafic mixing. The rhyolitic lava flow and dykes evolved in relatively shallower crustal magma chambers. Copyright © 2007 John Wiley & Sons, Ltd.
Heritability of “small‐world” networks in the brain: A graph theoretical analysis of resting‐state EEG functional connectivity
Authors: Smit Dirk J. A. , Stam Cornelis J. , Posthuma Danielle , Boomsma Dorret I. , de Geus Eco J. C. 
Published: December 2007

AbstractRecent studies have shown that resting‐state functional networks as studied with fMRI, EEG, and MEG may be so‐called small‐world networks. We investigated to what extent the characteristic features of small‐world networks are genetically determined. To represent functional connectivity between brain areas, we measured resting EEG in 574 twins and their siblings and calculated the synchronization likelihood between each pair of electrodes. We applied a threshold to obtain a binary graph from which we calculated the clustering coefficient C (describing local interconnectedness) and average path length L (describing global interconnectedness) for each individual. Modeling of MZ and DZ twin and sibling resemblance indicated that across various frequency bands 46–89% of the individual differences in C and 37–62% of the individual differences in L are heritable. It is asserted that C, L, and a small‐world organization are viable markers of genetic differences in brain organization. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.
Effects of acute dehydration on brain morphology in healthy humans
Authors: Kempton Matthew J. , Ettinger Ulrich , Schmechtig Anne , Winter Edward M. , Smith Luke , McMorris Terry , Wilkinson Iain D. , Williams Steven C.R. , Smith Marcus S. 
Published: December 2007

AbstractDehydration can affect brain structure which has important implications for human health. In this study, we measured regional changes in brain structure following acute dehydration. Healthy volunteers received a structural MRI scan before and after an intensive 90‐min thermal‐exercise dehydration protocol. We used two techniques to determine changes in brain structure: a manual point counting technique using MEASURE, and a fully automated voxelwise analysis using SIENA. After the exercise regime, participants lost (2.2% ± 0.5%) of their body mass. Using SIENA, we detected expansion of the ventricular system with the largest change occurring in the left lateral ventricle (P = 0.001 corrected for multiple comparisons) but no change in total brain volume (P = 0.13). Using manual point counting, we could not detect any change in ventricular or brain volume, but there was a significant correlation between loss in body mass and third ventricular volume increase (r = 0.79, P = 0.03). These results show ventricular expansion occurs following acute dehydration, and suggest that automated longitudinal voxelwise analysis methods such as SIENA are more sensitive to regional changes in brain volume over time compared with a manual point counting technique. Hum Brain Mapp 2009. © 2007 Wiley‐Liss, Inc.
Differential parametric modulation of self‐relatedness and emotions in different brain regions
Authors: Northoff Georg , Schneider Felix , Rotte Michael , Matthiae Christian , Tempelmann Claus , Wiebking Christina , Bermpohl Felix , Heinzel Alexander , Danos Peter , Heinze Hans‐Jochen , Bogerts Bernhard , Walter Martin , Panksepp Jaak 
Published: December 2007

AbstractOur sense of self is strongly colored by emotions although at the same time we are well able to distinguish affect and self. Using functional magnetic resonance imaging, we here tested for the differential effects of self‐relatedness and emotion dimensions (valence, intensity) on parametric modulation of neural activity during perception of emotional stimuli. We observed opposite parametric modulation of self‐relatedness and emotion dimensions in the dorsomedial prefrontal cortex and the ventral striatum/nucleus accumbens, whereas neural activity in subcortical regions (tectum, right amygdala, hypothalamus) was modulated by self‐relatedness and emotion dimensions in the same direction. In sum, our results demonstrate that self‐relatedness is closely linked to emotion dimensions of valence and intensity in many lower subcortical brain regions involved in basic emotional systems and, at the same time, distinct from them in higher cortical regions that mediate cognitive processes necessary for becoming aware of one's self, for example self‐consciousness. Hum Brain Mapp, 2009. © 2007 Wiley‐Liss, Inc.
Expression of free fatty acid receptor GPR40 in the neurogenic niche of adult monkey hippocampus
Authors: Ma Dexuan , Lu Li , Boneva Nadezhda B. , Warashina Shogo , Kaplamadzhiev Desislav B. , Mori Yoshimi , Nakaya Masa‐aki , Kikuchi Mitsuru , Tonchev Anton B. , Okano Hideyuki , Yamashima Tetsumori 
Published: December 2007

AbstractPolyunsaturated free fatty acids (PUFAs) are known to play critical roles for the development, maintenance, and function of the brain. Recently, we reported that G‐protein coupled receptor 40 (GPR40), one type of PUFA receptors, is expressed throughout the adult primate central nervous system including the hippocampus. This opens a possibility that PUFA might act as extracellular signaling molecules at the GPR40 receptor to regulate neuronal function. Here we studied protein expression of GPR40 in the neurogenic niche of the adult monkey hippocampus under normal and postischemic conditions. Confocal laser microscope analysis of immunostained sections revealed GPR40 immunoreactivity in neural progenitors, immature neurons, astrocytes and endothelial cells of the subgranular zone (SGZ) of the dentate gyrus (DG); a well‐known neurogenic niche within the adult brain. Immunoblotting analysis showed that the GPR40 protein increased significantly in the second week after global cerebral ischemia as compared with the control. This was compatible with the postischemic increment of GPR40‐positive cells in the SGZ as detected by immunofluorescence imaging. Taken together with our previous findings of the SGZ progenitor cell upregulation after ischemia, the present data suggest that PUFA such as docosahexaenoic acid may act via GPR40 to regulate adult hippocampal neurogenesis in primates. © 2007 Wiley‐Liss, Inc.
Cadherin‐8 and N‐cadherin differentially regulate pre‐ and postsynaptic development of the hippocampal mossy fiber pathway
Authors: Bekirov Iddil H. , Nagy Vanja , Svoronos Alexandra , Huntley George W. , Benson Deanna L. 
Published: December 2007

AbstractCells sort into regions and groups in part by their selective surface expression of particular classic cadherins during development. In the nervous system, cadherin‐based sorting can define axon tracts, restrict axonal and dendritic arbors to particular regions or layers, and may encode certain aspects of synapse specificity. The underlying model has been that afferents and their targets hold in common the expression of a particular cadherin, thereby providing a recognition code of homophilic cadherin binding. However, most neurons express multiple cadherins, and it is not clear whether multiple cadherins all act similarly in shaping neural circuitry. Here we asked how two such cadherins, cadherin‐8 and N‐cadherin, influence the guidance and differentiation of hippocampal mossy fibers. Using organotypic hippocampal cultures, we find that cadherin‐8 regulates mossy fiber fasciculation and targeting, but has little effect on CA3 dendrites. In contrast, N‐cadherin regulates mossy fiber fasciculation, but has little impact on axonal growth and targeting. However, N‐cadherin is essential for CA3 dendrite arborization. Both cadherins are required for formation of proper numbers of presynaptic terminals. Mechanistically, such differential actions of these two cadherins could, in theory, reflect coupling to distinct intracellular binding partners. However, we find that both cadherins bind β‐catenin in dentate gyrus (DG). This suggests that cadherins may engage different intracellular signaling cascades downstream of β‐catenin, coopt different extracellular binding partners, or target distinct subcellular domains. Together our findings demonstrate that cadherin‐8 and N‐cadherin are critical for generating the mossy fiber pathway, but that each contributes differentially to afferent and target differentiation, thereby complementing one another in the assembly of a synaptic circuit. © 2007 Wiley‐Liss, Inc.
Skeletal muscle cells express the profibrotic cytokine connective tissue growth factor (CTGF/CCN2), which induces their dedifferentiation
Authors: Vial Cecilia , Zúñiga Lidia Miriam , Cabello‐Verrugio Claudio , Cañón Pablo , Fadic Ricardo , Brandan Enrique 
Published: December 2007

AbstractFibrotic disorders are typified by excessive connective tissue and extracellular matrix (ECM) deposition that precludes normal healing processes of different tissues. Connective tissue growth factor (CTGF) seems to be involved in the fibrotic response. Several muscular dystrophies are characterized by a progressive weakness and wasting of the musculature, and by extensive fibrosis. However, the exact role of CTGF in skeletal muscle is unknown. Here we show that myoblasts and myotubes are able to synthesize CTGF in response to transforming growth factor type‐β (TGF‐β) and lysophosphatidic acid (LPA). CTGF induced several ECM constituents such as fibronectin, collagen type I and α4, 5, 6, and β1 integrin subunits in myoblasts and myotubes. CTGF had an important inhibitory effect on muscle differentiation evaluated by the decrease in the nuclear translocation of the early muscle regulatory factor myogenin and myosin. Remarkable, CTGF treatment of myoblasts induced their dedifferentiation, characterized by down regulating MyoD and desmin, two markers of committed myoblasts, together with a strong reorganization of cytoskeletal filaments. These results provide novel evidence for the underlying mechanisms and participation of skeletal muscle cells in the synthesis and role of CTGF inducing fibrosis, inhibiting myogenesis and dedifferentiating myoblasts. J. Cell. Physiol. 215: 410–421, 2008. © 2007 Wiley‐Liss, Inc.
Differential regulation of the lateral mobility of plasma membrane phospholipids by the extracellular matrix and cholesterol
Authors: Ramprasad O.G. , Rangaraj Nandini , Srinivas G. , Thiery Jean Paul , Dufour Sylvie , Pande Gopal 
Published: December 2007

AbstractIn this study, we compared qualitative and quantitative changes in the lateral mobility of phospholipid molecules in the plasma membrane of intact cells under various conditions of specific interaction of integrins in the cell membrane with two extracellular matrix (ECM) components viz. fibronectin (FN) and laminin (LN). We found a strong and specific correlation between the lower lateral mobility of phosphatidylcholine (PC) and higher lateral mobility of phosphatidylethanolamine (PE) when cells were expressing high levels of α5β1 integrin and thus were adherent and motile on FN. The interaction between PC and FN in α5 integrin expressing cells was aided by the strong affinity of α5 integrin to the FN matrix. Cholesterol was involved in regulating the lateral mobility of PC to a great extent and of PE to a lesser extent without affecting the overall microviscosity of the plasma membrane or the distribution of caveolin‐marked domains. The distribution and mobility of PC and PE molecules in the lamellipodial regions differed from that in the rest of the membrane and also in the more motile and in the less motile cells. We propose that these differences in distribution of PC and PE in different regions of cell membrane and their respective lateral mobility are observed due to the specific interaction of PC molecules with FN molecules in the ECM. Our results outline a new role of integrin–matrix interactions in the regulation of membrane phospholipid behavior. J. Cell. Physiol. 215: 550–561, 2008. © 2007 Wiley‐Liss, Inc.