bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intrinsic chiral domains enantioselectively segregated from twisted nematic cells of bent‐core mesogens
Authors: Choi Suk‐Won , Kang Sungmin , Takanishi Yoichi , Ishikawa Ken , Watanabe Junji , Takezoe Hideo 
Published: February 2007

AbstractEnantioselective segregation has been attained in the Bx phase of a novel substituted oxadiazole achiral banana‐shaped liquid crystal (LC) without introducing any chiral species. This bent‐core molecule exhibits LC polymorphism; the higher temperature nematic (N) phase and the lower temperature banana smectic phase (Bx phase), in which spontaneous chiral segregation with (+) and (−) chiral domains occurs with equal probabilities. In twisted cell geometries, extrinsically induced twisted N structures are formed and result in intrinsically chiral conglomorate when the temperature is decreased from N to Bx. The observed optical activity in homochiral Bx phase is comparable to those theoretically predicted and is proportional to the cell thickness. Chirality, 2007. © 2007 Wiley‐Liss, Inc.
The Natural Product Berberine is a Human Prolyl Oligopeptidase Inhibitor
Authors: Tarrago Teresa , Kichik Nessim , Seguí Josep , Giralt Ernest 
Published: February 2007

AbstractProlyl oligopeptidase is a cytosolic serine peptidase that hydrolyzes proline‐containing peptides at the carboxy terminus. This peptidase has been associated with schizophrenia, bipolar affective disorder, and related neuropsychiatric disorders, and therefore may have important clinical implications. Among the strategies used to find novel prolyl oligopeptidase inhibitors, traditional Chinese medicinal plants provide a rich source of unexplored compounds. We used 19F NMR spectroscopy to search for new prolyl oligopeptidase inhibitors in a library of traditional Chinese medicine plant extracts. Several extracts were identified as powerful inhibitors of this peptidase. The alkaloid berberine was the prolyl oligopeptidase inhibitory molecule isolated from Rhizoma coptidis extract. Berberine inhibited prolyl oligopeptidase in a dose‐dependent manner. As berberine is a natural compound that has been safely administered to humans, it opens up new perspectives for the treatment of neuropsychiatric diseases. The results described herein suggest that the initiation of clinical trials in patients with schizophrenia, bipolar affective disorder, or related diseases in which cognitive capabilities are affected should be undertaken with either the extract or pure BBR.
Expression of the mRNAs encoding for the vesicular glutamate transporters 1 and 2 in the rat thalamus
Authors: Barroso‐Chinea Pedro , Castle María , Aymerich María S. , Pérez‐Manso Mónica , Erro Elena , Tuñon Teresa , Lanciego José L. 
Published: February 2007

AbstractVesicular glutamate transporters (VGLUTs) are responsible for glutamate trafficking and for the subsequent regulated release of this excitatory neurotransmitter at the synapse. Three isoforms of the VGLUT have been identified, now known as VGLUT1, VGLUT2, and VGLUT3. Both VGLUT1 and VGLUT2 have been considered definitive markers of glutamatergic neurons, whereas VGLUT3 is expressed in nonglutamatergic neurons such as cholinergic striatal interneurons. It is widely believed that VGLUT1 and VGLUT2 are expressed in a complementary manner at the cortical and thalamic levels, suggesting that these glutamatergic neurons fulfill different physiological functions. In the present work, we analyzed the pattern of VGLUT1 and VGLUT2 mRNA expression at the thalamic level by using single and dual in situ hybridization. In accordance with current beliefs, we found significant expression of VGLUT2 mRNA in all the thalamic nuclei, while moderate expression of VGLUT1 mRNA was consistently found in both the principal relay and the association thalamic nuclei. Interestingly, individual neurons within these nuclei coexpressed both VGLUT1 and VGLUT2 mRNAs, suggesting that these individual thalamic neurons may have different ways of trafficking glutamate. These results call for a reappraisal of the previously held concept regarding the mutually exclusive distribution of VGLUT transporters in the central nervous system. J. Comp. Neurol. 501:703–715, 2007. © 2007 Wiley‐Liss, Inc.
Structural changes at synapses after delayed perfusion fixation in different regions of the mouse brain
Authors: Tao‐Cheng Jung‐Hwa , Gallant Paul E. , Brightman Milton W. , Dosemeci Ayse , Reese Thomas S. 
Published: February 2007

AbstractWe recently showed by electron microscopy that the postsynaptic density (PSD) from hippocampal cultures undergoes rapid structural changes after ischemia‐like conditions. Here we report that similar structural changes occur after delay in transcardial perfusion fixation of the mouse brain. Delay in perfusion fixation, a condition that mimics ischemic stress, resulted in 70%, 90%, and 23% increases in the thickness of PSDs from the hippocampus (CA1), cerebral cortex (layer III), and cerebellar cortex (Purkinje spines), respectively. In step with PSD thickening, the amount of PSD‐associated α‐calcium calmodulin‐dependent protein kinase II (α‐ CaMKII) label increased more in cerebral cortical spines than in Purkinje spines. Although the Purkinje PSDs thickened only slightly after delayed fixation, they became highly curved, and many formed sub‐PSD spheres ∼80 nm in diameter that labeled for CaMKII. Delayed perfusion fixation also produced more cytoplamic CaMKII clusters (∼110 nm in diameter) in the somas of pyramidal cells (from hippocampus and cerebral cortex) than in Purkinje cells. Thus a short delay in perfusion fixation produces cell‐specific structural changes at PSDs and neuronal somas. Purkinje cells respond somewhat differently to delayed perfusion fixation, perhaps owing to their lower levels of CaMKII, and CaMKII binding proteins at PSDs. We present here a catalogue of structural changes that signal a perfusion fixation delay, thereby providing criteria by which to assess perfusion fixation quality in experimental structural studies of brain and to shed light on the subtle changes that occur in intact brain following metabolic stress. J. Comp. Neurol. 501:731–740, 2007. © 2007 Wiley‐Liss, Inc.
Retinal horizontal cell‐specific promoter activity and protein expression of zebrafish connexin 52.6 and connexin 55.5
Authors: Shields Colleen R. , Klooster Jan , Claassen Yvonne , Ul‐Hussain Mahboob , Zoidl Georg , Dermietzel Rolf , Kamermans Maarten 
Published: February 2007

AbstractConnexins in retinal horizontal cells (HC) function in the processing of visual information. For example, gap junction‐forming connexins may contribute to the spatial integration of visual stimuli. Additionally, connexin hemichannels have been hypothesized to participate in the feedback pathway from HCs to cones. To verify the identities of the zebrafish HC connexins, we performed promoter expression and immunohistochemical studies of connexin 52.6 (Cx52.6) and Cx55.5. Zebrafish embryos were microinjected with Cx52.6 or Cx55.5 promoter sequences and a green fluorescent protein reporter construct. Light and electron microscopic (EM) analysis showed green fluorescent protein expression exclusively in retinal HCs. Immunohistochemistry confirmed that HCs express Cx52.6 and Cx55.5 proteins. Light microscopy revealed Cx52.6 and Cx55.5 in the retinal inner nuclear and outer plexiform layers. Double labeling for Cx55.5 or Cx52.6 and cell‐specific markers (tyrosine hydroxylase, protein kinase C‐α, or GluR2) demonstrated that these connexins do not localize to interplexiform or ON bipolar cells, but most likely are present in HCs. Preembedding immuno‐EM confirmed the HC‐specific expression of Cx52.6 and Cx55.5 and illustrated the presence of these two connexins in gap junctions between HCs. The EM data also revealed robust labeling for Cx55.5 in hemichannels on HC dendrites in photoreceptor synaptic terminals. Voltage‐clamp experiments in cultured cells demonstrated that Cx55.5‐containing hemichannels can open at physiological membrane potentials. These results offer the first in vivo demonstration of the HC‐specific activities of the Cx52.6 and Cx55.5 promoters. Furthermore, these data provide the first proof at the protein level for retinal HC‐specific connexins in the zebrafish. J. Comp. Neurol. 501:765–779, 2007. © 2007 Wiley‐Liss, Inc.
Effect of Branching on Two‐Photon Absorption in Triphenylbenzene Derivatives
Authors: Terenziani Francesca , Le Droumaguet Céline , Katan Claudine , Mongin Olivier , Blanchard‐Desce Mireille 
Published: February 2007

AbstractThe photophysical and linear and nonlinear spectral properties of octupolar compounds with a triphenylbenzene core are investigated and compared with properties of corresponding dipolar branches. A correlation is found between the solvatochromic behavior and the two‐photon absorption cross section. Moreover, the nature of the core is found to be responsible for the nature of the coupling between branches; in the studied case only (weak) electrostatic interactions are effective, while other cores, like the triphenylamine moiety, are able to promote coherent coupling between the branches, leading to strongly nonadditive properties.
The Shape of Leucine in the Gas Phase
Authors: Cocinero Emilio J. , Lesarri Alberto , Grabow Jens‐Uwe , López Juan C. , Alonso José L. 
Published: February 2007

AbstractTwo structures of neutral leucine are detected in the jet‐cooled rotational spectrum of a laser‐ablation molecular‐beam Fourier transform microwave (LA‐MB‐FTMW) experiment. The comparison between the experimental rotational and 14N nuclear quadrupole coupling constants and those calculated ab initio provides conclusive evidence for the identification of the conformers. The most stable species is stabilized by a NH⋅⋅⋅O=C intramolecular hydrogen bond and a cis‐COOH interaction, while a higher‐energy conformer exhibits a N⋅⋅⋅HO intramolecular hydrogen bond and trans‐COOH, as in lower aliphatic amino acids. The isobutyl side chain adopts the same configuration in the two conformers of leucine, characterized by a trans arrangement of the C′CαCβCγCδ chain. The differences with the preferred side chain configurations observed in valine and isoleucine are discussed.
Neuronal control of myogenic regulatory factor accumulation in fetal muscle
Authors: Washabaugh Charles H. , Ontell Martin P. , Shand Stuart H. , Bradbury Neil , Kant Jeffrey A. , Ontell Marcia 
Published: February 2007

AbstractThe lumbosacral spinal cords of 14.5‐day gestation mice (E14.5) were ablated. The number of molecules of each of the four myogenic regulatory factor (MRF) mRNAs per nanogram of total RNA were evaluated in innervated and aneural fetal crural muscles. Accumulation of all four MRF mRNAs was affected in aneural muscle, but was never more than threefold different than in innervated muscles, considerably less than after adult denervation. The effect of the nerve varied with the MRF, the fetal age, and with the muscle (extensor digitorum longus muscle [EDL] vs. soleus muscle), with the nerve having multiple effects including down‐regulation of certain MRF genes at specific periods (e.g., myoD and myogenin [E16.5–E18.5] and MRF4 in the EDL only [E18.5–E19.5]); limiting the up‐regulation of certain genes, which occurred in the absence of innervation (e.g., myf‐5 [E18.5–E19.5] and myogenin [E14.5–E16.5]); and even enhancing the accumulation of MRF4 mRNA (E14.5–E16.5). We hypothesize that factors other than nerve contribute to the down‐regulation of myf‐5 and myogenin mRNAs to adult levels. Innervation was required for the emergence of the slow, but not the fast, MRF mRNA profile at birth. MyoD, found in both the nuclear and cytoplasmic protein extracts of innervated fetal muscle, increased by ∼5‐fold in the nuclear extracts (∼2.5‐fold in the cytoplasmic) of E19.5 aneural muscles, significantly less than the 12‐fold increase found in the nuclear extract of 4‐day denervated adult muscle. This increase in aneural fetal muscle was due primarily to an increased concentration of myoD in muscle lineage nuclei, rather than to the presence of additional myoD+ muscle lineage nuclei. Developmental Dynamics 236:732–745, 2007. © 2007 Wiley‐Liss, Inc.
Expression of Cre recombinase in early diploid trophoblast cells of the mouse placenta
Authors: Wenzel Pamela L. , Leone Gustavo 
Published: February 2007

AbstractAn increasing number of genes known to be critical for cell cycle control, differentiation, and tumor suppression have been found to impact development of the placenta. To elucidate how these genes contribute to development of embryonic and extra‐embryonic lineages, we generated a transgenic mouse in which the Cre transgene is driven by placenta‐specific regulatory sequences from the human CYP19 gene. Using ROSA26 conditional reporter mice, we could detect expression of the CYP19‐Cre transgene throughout the extra‐embryonic ectoderm and in the ectoplacental cone at embryonic day 6.5 (E6.5). By E11.5, recombination of LoxP reporter sites was detected in all derivatives of trophoblast stem cells, including spongiotrophoblast, giant cells, and labyrinth trophoblasts. We conclude that the CYP19‐Cre transgenic mouse developed here can be used in combination with conditional alleles to distinguish between embryonic and extra‐embryonic gene function, and to begin to map the period of time when gene function is critical during development. genesis 45:129–134, 2007. © 2007 Wiley‐Liss, Inc.
The B lineage potential of thymus settling progenitors is critically dependent on mouse age
Authors: Ceredig Rhodri , Bosco Nabil , Rolink Antonius G. 
Published: February 2007

AbstractThe nature and lineage potential, particularly that for B cells, of thymus settling progenitors (TSP) in the adult mouse has been the subject of considerable debate. Lack of B cell potential would suggest pre‐thymic, whereas its presence would suggest intra‐thymic loss of B cell potential. Using limiting dilution analysis (LDA) in vitro and transfer experiments in vivo, we show that the B cell potential of TSP is critically dependent on mouse age, reaching a maximum of about 1 in 20 cells at birth, decreasing 50‐fold in adult mice. Cells with a TSP phenotype can be found in the neonatal blood. Furthermore, using LDA, we show that Notch ligand signaling of TSP results in the loss of B cell potential with a half‐life of approximately 12 h. Taken together, these results indicate that loss of B cell potential by TSP is an intra‐thymic event and highlight the developmental pressure acting on the immune system to rapidly colonize primary lymphoid organs with functional progenitors. This critical time coincides with birth in the mouse. In the adult mouse, we estimate than only about 5 TSP cells/day would be required to maintain steady‐state thymopoiesis.
Potent T cell agonism mediated by a very rapid TCR/pMHC interaction
Authors: Boulter Jonathan M. , Schmitz Nicole , Sewell Andrew K. , Godkin Andrew J. , Bachmann Martin F. , Gallimore Awen M. 
Published: February 2007

AbstractThe interaction between T cell receptors (TCR) and peptide‐major histocompatibility complex (pMHC) antigens can lead to varying degrees of agonism (T cell activation), or antagonism. The P14 TCR recognises the lymphocytic choriomeningitis virus (LCMV)‐derived peptide, gp33 residues 33–41 (KAVYNFATC), presented in the context of H‐2Db. The cellular responses to various related H‐2Db peptide ligands are very well characterised, and P14 TCR‐transgenic mice have been used extensively in models of virus infection, autoimmunity and tumour rejection. Here, we analyse the binding of the P14 soluble TCR to a broad panel of related H‐2Db‐peptide complexes by surface plasmon resonance, and compare this with their diverse cellular responses. P14 TCR binds H‐2Db‐gp33 with a KD of 3 µM (±0.5 µM), typical of an immunodominant antiviral TCR, but with unusually fast kinetics (koff = 1 s–1), corresponding to a half‐life of 0.7 s at 25°C, outside the range previously observed for murine agonist TCR/pMHC interactions. The most striking feature of these data is that a very short half‐life does not preclude the ability of a TCR/pMHC interaction to induce antiviral immunity, autoimmune disease and tumour rejection.
Intra‐ and Intermolecular H···Cl–Ni Bonding Patterns in a Series of Highly Preorganized Dinuclear Nickel(II) Complexes
Authors: Nie Feng‐Mei , Leibeling Guido , Demeshko Serhiy , Dechert Sebastian , Meyer Franc 
Published: February 2007

AbstractFour dinickel complexes [L1Ni2(μ‐Cl)(Cl)2]·2CH3OH (1a), [L1Ni2(μ‐Cl)(CH3OH)](ClO4)2 (1b), [L2Ni2(μ‐Cl)Cl2(H2O)2]·H2O (2) and [L3Ni2Cl2(CH3OH)2]Cl·2CH3OH (3) were synthesized and structurally characterized. The ligand scaffolds have a central pyrazolato bridge and N‐donor chelate arms that provide two proximate binding pockets for the nickel ions. While the longer ligand side arms in 1a, 1b and 2 induce Ni···Ni distances of around 4.0 Å and favour incorporation of a chlorido bridge within the dimetallic pocket, a stretched Ni···Ni separation of 4.6 Å with an unusual intramolecular Cl···H–O linkage is observed in 3. Various Cl···H–O hydrogen‐bonding motifs are identified in the solid‐state structures of 1–3, where either the H‐donor (MeOH or H2O) or the H‐acceptor (chlorido) or both are bound to a nickel ion, and their relative donor–acceptor distances are discussed. Magnetic coupling mediated through the pyrazolato and chlorido bridges is rather weak and antiferromagnetic, but it is even weaker for the Cl···H–O linkage. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Octahedral Metal Clusters [Nb6Cl12(CN)6]4– as Molecular Building Blocks: From Supramolecular Assemblies to Coordination Polymers
Authors: Zhou Huajun , Lachgar Abdessadek 
Published: February 2007

AbstractThere are considerable advantages for using metal clusters as building units of supramolecular materials because of their unique structural, chemical, and physical properties, all of which fall in between normal valence compounds and the metals. In this microreview, we describe the synthetic methodology and structural properties of recent findings in the use of octahedral niobium hexacyanochloride anions as building units of assemblies of different size, charge, and dimensionality. We focus on the use of a metal‐directed approach to prepare cluster‐based supramolecular assemblies and coordination polymers with one‐, two‐, and three‐dimensional frameworks. The materials described herein are all built from diamagnetic cyanochloride cluster anions [Nb6Cl12(CN)6]4– and coordinatively unsaturated metal complexes such as [Mn(salen)]+ and their derivatives. The overall structures are largely determined by the number of coordination sites available for linkage to the cluster unit and coordination preferences of the metal complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Suitable cooling program for chicken fat dry fractionation
Authors: Arnaud Elodie , Pina Michel , Collignan Antoine 
Published: February 2007

AbstractThe impacts of the cooling program on crystal morphology, crystal suspension filtration properties and the characteristics of fractions resulting from chicken fat dry fractionation were assessed. The quality of the fractions was found to depend on the nature of the crystallized material and was also closely related to the filtration properties of the crystal suspension, which in turn were controlled by the cooling conditions. A slow cooling rate during the nucleation step was necessary to enhance process selectivity, and this rate could be accelerated once the first crystals had formed. These findings enhanced our understanding of the mechanisms involved during dry fractionation and highlighted the efficacy of a three‐phase cooling program, including (1) cooling from 70 to 26 °C, (2) slowdown in the cooling rate, and (3) a second rapid cooling down to the final temperature at which the fat is held for a specified time.
Effect of chemical interesterification on triacylglycerol and solid fat contents of palm stearin, sunflower oil and palm kernel olein blends
Authors: Dian Noor Lida Habi Mat , Sundram Kalyana , Idris Nor Aini 
Published: February 2007

AbstractPalm stearin (POs) with an iodine value of 41.4, sunflower oil (SFO) and palm kernel olein (PKOo) were blended in various ratios according to a three‐component mixture design and subjected to chemical interesterification (CIE). Triacylglycerol (TAG) and solid fat content (SFC) profiles of the chemically interesterified (CIEed) blends were analyzed and compared with those of the corresponding non‐CIEed blends. Upon CIE, extensive rearrangement of fatty acids (FA) among TAG was evident. The concentrations of several TAG were increased, some decreased and several new TAG might also have been formed. The changes in the TAG profiles were reflected in the SFC profiles of the blends. The SFC of the CIEed blends, except the binary blends of POs/PKOo which experienced an increase in SFC following CIE, revealed that they were softer than their respective starting blends. Randomization of FA distribution within and among TAG molecules of POs and PKOo led to a modification in TAG composition of the POs/PKOo blends and improved miscibility between the two fats, and consequently diminished the eutectic interaction that occurred between POs and PKOo.
Lipid extraction from the microalga Phaeodactylum tricornutum
Authors: Fajardo Antonio Ramírez , Cerdán Luis Esteban , Medina Alfonso Robles , Fernández Fracisco Gabriel Acién , Moreno Pedro A. González , Grima Emilio Molina 
Published: February 2007

AbstractEthanol was used for the extraction and purification of lipids from the biomass of the microalga Phaeodactylum tricornutum. This microalga is an oil‐rich substrate with a high proportion of eicosapentaenoic acid (EPA). The process consisted of two steps. First, ethanol (96% vol/vol) was used to extract the lipids from the lyophilized biomass. Second, a biphasic system was formed by adding water and hexane to the extracted crude oil. In this way, most of the lipids were transferred to the hexanic phase while most impurities remained in the hydroalcoholic phase. The first step was carried out by two consecutive extractions at room temperature, each with 5 mL ethanol per gram of biomass, for 10 and 1.25 h, respectively. Under these conditions, over 90% of the saponifiable lipids in the biomass were extracted. In the second step, the percentage of water in the hydroalcoholic phase, the hexane/hydroalcoholic phase ratio and the number of extraction steps were optimized. A water content of 40% vol/vol in the hydroalcoholic phase provided the highest lipid recovery. A recovery yield of 80% was obtained by four consecutive extractions with a hexane/hydroalcoholic phase ratio of 0.2 (vol/vol). Equilibrium distribution data of the lipids between the hydroethanolic and the hexanic phases were also obtained in order to predict the lipid recovery yield of the extraction. This process is an alternative to the traditional methods of lipid extraction, which uses less toxic solvents and reduces the total amount of solvents used.