bluuebunny/crossref_metadata_2025_split huggingface dataset:
Total Synthesis of (−)‐Doliculide, Structure–Activity Relationship Studies and Its Binding to F‐Actin
Authors: Matcha Kiran , Madduri Ashoka V. R. , Roy Sayantani , Ziegler Slava , Waldmann Herbert , Hirsch Anna K. H. , Minnaard Adriaan J. 
Published: November 2012

AbstractActin, an abundant protein in most eukaryotic cells, is one of the targets in cancer research. Recently, a great deal of attention has been paid to the synthesis and function of actin‐targeting compounds and their use as effective molecular probes in chemical biology. In this study, we have developed an efficient synthesis of (−)‐doliculide, a very potent actin binder with a higher cell‐membrane permeability than phalloidin. Actin polymerization assays with (−)‐doliculide and two analogues on HeLa and BSC‐1 cells, together with a prediction of their binding mode to F‐actin by unbiased computational docking, show that doliculide stabilizes F‐actin in a similar way to jasplakinolide and chondramide C.
A Gene‐Fusion Approach to Enabling Plant Cytochromes P450 for Biocatalysis
Authors: Schückel Julia , Rylott Elizabeth L. , Grogan Gideon , Bruce Neil C. 
Published: November 2012

AbstractCytochromes P450 from plants have the potential to be valuable catalysts for industrial hydroxylation reactions, but their application is hindered by poor solubility, the lack of suitable expression systems and the requirement of P450s for auxiliary redox‐transport proteins for the delivery of reducing equivalents from NAD(P)H. In the interests of enabling useful P450 activity from plants, we have developed a suite of vectors for the expression of plant P450s as non‐natural genetic fusions with reductase proteins. First, we have fused the P450 isoflavone synthase (IFS) from Glycine max with the bacterial P450 reductase domain (Rhf‐RED) from Rhodococcus sp., by using our LICRED vector developed previously (F. Sabbadin, R. Hyde, A. Robin, E.‐M. Hilgarth, M. Delenne, S. Flitsch, N. Turner, G. Grogan, N. C. Bruce, ChemBioChem 2010, 11, 987–994) creating the first active bacterial–plant fusion P450 enzyme. We have then created a complementary vector, ACRyLIC for the fusion of selected plant P450 enzymes to the P450 reductase ATR2 from Arabidopsis thaliana. The applicability of this vector to the creation of active P450 fusion enzymes was demonstrated using both IFS1 and the cinnamate‐4‐hydroxylase (C4H) from A. thaliana. Overall the fusion vector systems will allow the rapid creation of libraries of plant P450s with the aim of identifying enzyme activities with possible applications in industrial biocatalysis.
Biocatalysis: Key to Selective Oxidations
Authors: Schulz Sebastian , Girhard Marco , Urlacher Vlada B. 
Published: November 2012

AbstractSelective oxidations of readily available organic molecules can lead directly to high‐value chiral compounds. Although modern chemical catalysts have significantly been improved toward the selective hydroxylation of nonactivated CH bonds, cytochrome P450 monooxygenases still remain unsurpassed in their regio‐, chemo‐, and stereoselectivity. The exploitation of new P450 enzymes discovered through genome mining provides sought‐after fine chemicals, drugs, drug metabolites, and vitamins and has already been proven superior to classical chemical synthesis in many cases. Here, we provide examples for highly selective oxidations achieved through the exploitation of naturally occurring (wild‐type) P450 monooxygenases. We summarize recent achievements in the area of P450 biocatalysis and present examples for applications of P450s in industrial synthetic chemistry.
Molecular Ionics in Supramolecular Assemblies with Channel Structures Containing Lithium Ions
Authors: Moriya Makoto , Kitaguchi Hiro , Nishibori Eiji , Sawa Hiroshi , Sakamoto Wataru , Yogo Toshinobu 
Published: November 2012

AbstractA novel trilithium compound, Li3[B(C6H4O2){O(CH2CH2O)3CH3}2][N(SO2CF3)2]2 (1‐2.0), with solid‐state ionic conductivity was synthesized. The crystal structure of 1‐2.0 consists of the one‐dimensional ionic conduction paths. The paths were afforded as a result of the self‐assembled stacking of the component molecules of 1‐2.0 with channel structures containing lithium ions. In this supramolecule, one lithium ion holds the component molecules in specific positions to construct a supramolecular structure with thermally stable ionic conduction paths and the others behave as carrier ions exhibiting selective lithium‐ion conductivity. Owing to the existence of both roles for the lithium ions, this electrolyte shows selective lithium‐ion conductivity.
Multivalent Design of Apoptosis‐Inducing Bid‐BH3 Peptide–Oligosaccharides Boosts the Intracellular Activity at Identical Overall Peptide Concentrations
Authors: Richter Martin , Chakrabarti Alokta , Ruttekolk Ivo R. , Wiesner Burkhard , Beyermann Michael , Brock Roland , Rademann Jörg 
Published: November 2012

AbstractMultivalent peptide–oligosaccharide conjugates were prepared and used to investigate the multivalency effect concerning the activity of Bid‐BH3 peptides in live cells. Dextran oligosaccharides were carboxyethylated selectively in the 2‐position of the carbohydrate units and activated for the ligation of N‐terminally cysteinylated peptides. Ligation through maleimide coupling was found to be superior to the native chemical ligation protocol. Monomeric Bid‐BH3 peptides were virtually inactive, whereas pentameric peptide conjugates induced apoptosis up to 20‐fold stronger at identical peptide concentrations. Comparison of lowly multivalent and highly multivalent peptide dextrans proved a multivalency effect in life cells which was specific for the BH3 peptide sequence.
In Situ Gel‐to‐Crystal Transition and Synthesis of Metal Nanoparticles Obtained by Fluorination of a Cyclic β‐Aminoalcohol Gelator
Authors: Xu Yang , Kang Chuanqing , Chen Yu , Bian Zheng , Qiu Xuepeng , Gao Lianxun , Meng Qingxin 
Published: November 2012

AbstractA new fluorinated version of a cyclic β‐aminoalcohol gelator derived from 1,2,3,4‐tetrahydroisoquinoline is presented. The gelator is able to gel various nonprotic solvents through OH⋅⋅⋅N hydrogen bonds and additional CH⋅⋅⋅F interactions due to the introduction of fluorine. A bimolecular lamellar structure is formed in the gel phase, which partly preserves the pattern of molecular organization in the single crystal. The racemate of the chiral gelator shows lower gelation ability than its enantiomer because of a higher tendency to form microcrystals, as shown by X‐ray diffraction analysis. The influence of fluorination on the self‐assembly of the gelator and the properties of the gel was investigated in comparison to the original fluorine‐free gel system. The introduction of fluorine brings two new features. The first is good recognition of o‐xylene by the gelator, which induces an in situ transition from gels of o‐xylene and of an o‐xylene/toluene mixture to identical single crystals with unique tubular architecture. The second is the enhanced stability of the toluene gel towards ions, including quaternary ammonium salts, which enables the preparation of a stable toluene gel in the presence of chloroaurate or chloroplatinate. The gel system can be used as a template for the synthesis of spherical gold nanoparticles with a diameter of 5 to 9 nm and wormlike platinum nanostructures with a diameter of 2 to 3 nm and a length of 5 to 12 nm. This is the first example of a synthesis of platinum nanoparticles in an organogel medium. Therefore, the appropriate introduction of a fluorine atom and corresponding nonbonding interactions into a known gelator to tune the properties and functions of a gel is a simple and effective tactic for design of a gel system with specific targets.
Self‐Assembly of a Mononuclear [FeIII(L)(EtOH)2] Complex Bearing an n‐Dodecyl Chain on Solid Highly Oriented Pyrolytic Graphite Surfaces
Authors: Ako Ayuk M. , Alam Mohammad Sahabul , Rahman Mostafizur , Hill Jonathan P. , Sanchez‐Ballester Noelia M. , Ariga Katsuhiko , Buth Gernot , Anson Christopher E. , Powell Annie K. 
Published: November 2012

AbstractThe synthesis and structures of the N‐[(2‐hydroxy‐3‐methyl‐5‐dodecylphenyl)methyl]‐N‐(carboxymethyl)glycine disodium salt (HL) ligand and its neutral mononuclear complex [FeIII(L)(EtOH)2] (1) are reported. Structural and electronic properties of 1 were investigated by using scanning tunneling microscopy (STM) and current imaging tunneling spectroscopy (CITS) techniques. These studies reveal that molecules of 1 form well‐ordered self‐assemblies when deposited on a highly oriented pyrolytic graphite (HOPG) surface. At low concentrations, single or double chains (i.e., nanowires) of the complex were observed, whereas at high concentration the complex forms crystals and densely packed one‐dimensional structures. In STM topographies, the dimensions of assemblies of 1 found on the surface are consistent with dimensions obtained from X‐ray crystallography, which indicates the strong similarities between the crystal form and surface assembled states. Double chains are attributed to hydrogen‐bonding interactions and the molecules align preferentially along graphite defects. In the CITS image of complex 1 a strong tunneling current contrast at the positions of the metal ions was observed. These data were interpreted and reveal that the bonds coordinating the metal ions are weaker than those of the surrounding ligands; therefore the energy levels next to the Fermi energy of the molecule should be dominated by metal‐ion orbitals.
Shifts in the ESR Spectra of Alkali‐Metal Atoms (Li, Na, K, Rb) on Helium Nanodroplets
Authors: Hauser Andreas W. , Gruber Thomas , Filatov Michael , Ernst Wolfgang E. 
Published: November 2012

AbstractHe‐droplet‐induced changes of the hyperfine structure constants of alkali‐metal atoms are investigated by a combination of relativistically corrected ab initio methods with a simulation of the helium density distribution based on He density functional theory. Starting from an accurate description of the variation of the hyperfine structure constant in the M–He diatomic systems (M=Li, Na, K, Rb) as a function of the interatomic distance we simulate the shifts induced by droplets of up to 10 000 4He atoms. All theoretical predictions for the relative shifts in the isotropic hyperfine coupling constants of the alkali‐metal atoms attached to helium droplets of different size are then tied to a single, experimentally derived parameter of Rb.
The effects of vitamin D3 during pregnancy and lactation on offspring physiology and behavior in Sprague–Dawley rats
Authors: Pan Pauline , Jin Daniel H.S. , Chatterjee‐Chakraborty Munmun , Halievski Katherine , Lawson Daeria , Remedios David , Smetka Cassandra , Pinto Vania , Parra Esteban , Fleming Alison S. 
Published: November 2012

AbstractRecent findings show that developmental vitamin D deficiency leads to altered brain morphology and behavioral development in the rat offspring. We examined the effects of different dietary vitamin D levels in rat dams on behavior and biochemistry of the offspring. Females were divided into five conditions and received diets containing 0, 1,5, 3.3, 6.0, or 10.0 IU/g of vitamin D3 from mating to weaning. Offspring were tested as juveniles and as adults for anxiety, social learning and behavior, and locomotion. Results show that both deficient and excessive levels of vitamin D3 in juveniles lead to altered physiology and behavior. In juveniles but not adults, variations in vitamin D were related to variations in measures of anxiety and marginally, activity levels. For social behaviors, both juveniles and adults were affected by mothers' diets. In general, offspring of animals receiving abnormal concentrations of vitamin D showed the most deficits. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 56: 12–22, 2014.
Ephrin‐B stimulation of calvarial bone formation
Authors: Benson M. Douglas , Opperman Lynne A. , Westerlund Jan , Fernandez Claudia R. , San Miguel Symone , Henkemeyer Mark , Chenaux George 
Published: November 2012

AbstractIntroduction: Ephrin‐B2 on osteoclasts was reported to promote bone formation as part of homeostasis by activating the EphB4 tyrosine kinase receptor on osteoblasts. Little is known about the role of ephrin‐B signaling to EphBs in developmental bone formation. Results: We observed expression of an ephrin‐B2 LacZ chimeric allele in the periosteum, sutural bone fronts, and dura mater of embryonic and neonatal mice. Expression in the adult skull was confined to sutures, but was heavily upregulated at sites of bone injury. Culture of embryonic calvariae with soluble recombinant ephrin‐B2/Fc doubled their bone content without altering suture width or overall skull morphology. Ephrin‐B2/Fc also stimulated osteoblast marker gene expression in cultured MC3T3 preosteoblastic cells without the need for type 1 collagen‐induced differentiation. EphB4 was absent in embryonic and adult skulls. However, EphB1 and EphB2, both physiological receptors for ephrin‐Bs, were expressed at sites of osteogenesis, and EphB1 knockout mice displayed a reduction in calvarial bone content compared to controls. Conclusions: These data support a role for ephrin‐B2 in the development and healing of bone through activation of osteoblast‐specific gene expression. EphB1 and EphB2 are likely candidates receptors for the ephrin‐B2 in bone. Developmental Dynamics, 2012. © 2012 Wiley Periodicals, Inc.
The interactions of the flow regime and the terrestrial ecology of the Mana floodplains in the middle Zambezi river basin
Authors: Ncube Sikhululekile , Beevers Lindsay , Hes Edwin M. A. 
Published: November 2012

ABSTRACTThe flow regime of a river is the main driver of the processes that make up a floodplain ecosystem. Changes in a flow regime will therefore result in changes in the floodplain. The Mana floodplains in the middle Zambezi river basin have been impacted by the construction of the Kariba dam as indicated by the decline in the population of mature, Faidherbia albida (F. albida) trees and the absence young trees. However, the relationship between the effects of the river impoundment, some 50 years ago, and the current ecological state of the floodplain is not well understood. Hence, this study is aimed at describing the historic (pre‐Kariba and post‐Kariba dam) and the current terrestrial ecological state of the Mana floodplains. Data was gathered through review of literature, archival records and hydrological records. Furthermore, vegetation plots were set up to measure diameter at breast height (dbh) of F. albida trees and hence describe the current F. albida stand structure. Results from this study show that the Kariba dam altered the peak mean monthly flows by about 60%. The frequency distribution of the dbh sizes of the current F. albida trees depicted an even‐aged stand structure (mean dbh of 103 cm). There was no evidence of growth of young F. albida trees as there were no trees with smaller (less than 40 cm) dbh sizes. The dry season densities of elephants, (Loxodonta africana) on the Mana floodplains have been increasing since the 1990s, and these also seem to have impacted on the F. albida stand structure. This perhaps partially has to do with the increased length of the dry season as a result of the changed river flows. Therefore, the influence of the altered flow regime and the impact of wildlife have acted interdependently in influencing the noted detectable changes to the ecology of the Mana floodplains. Copyright © 2012 John Wiley & Sons, Ltd.
Protein‐Directed In Situ Synthesis of Gold Nanoparticles on Reduced Graphene Oxide Modified Electrode for Nonenzymatic Glucose Sensing
Authors: Liu Yang , Dong Yongqiang , Guo Chun Xian , Cui Zhiming , Zheng Lianxi , Li Chang Ming 
Published: November 2012

AbstractA novel nonenzymatic glucose sensor was developed based on well‐dispersed gold nanoparticles, which were in situ grown under direction of protein on a reduced graphene oxide modified electrode. This electrode exhibited high electrocatalytic activity towards glucose oxidation without use of any enzyme or mediator. In application for the amperometric detection of glucose, a wide linear range of 0.02–16.6 mM, low detection limit of 5 µM and good selectivity were obtained. The attractive analytical performances of the proposed glucose sensor, coupled with the facile preparation method, provide a promising electrochemical platform for the development of effective nonenzymatic sensors.
Functional connectivity networks associated with chronic musculoskeletal pain in old age
Authors: Duke Han S. , Buchman Aron S. , Arfanakis Konstantinos , Fleischman Debra A. , Bennett David A. 
Published: November 2012

ObjectiveMusculoskeletal disorders are common and often lead to chronic pain in older adults. Because the efficacy of interventions varies with the duration of pain, the identification of early biomarkers for chronic pain would have important public health consequences. Imaging of functional connectivity differences between brain regions might identify some of the earliest functional consequences of a disease process. We tested the hypothesis that chronic musculoskeletal pain in older persons is associated with changes in functional brain connectivity.MethodWe used resting‐state functional magnetic resonance imaging and a spherical seed‐based region of interest approach to assess functional connectivity of brain regions on a sample of 128 (64 who reported chronic musculoskeletal pain and 64 demographically matched, pain free) nondemented older adults from the Memory and Aging Project, a clinical‐pathological cohort study of aging and dementia.ResultsOlder adults with chronic pain showed greater functional connectivity between the posterior cingulate and left insula, left superior temporal gyrus, and left cerebellum.ConclusionChronic musculoskeletal pain is associated with a specific pattern of functional connectivity between brain regions among older adults. Copyright © 2012 John Wiley & Sons, Ltd.
Single ketamine infusion in bipolar depression resistant to antidepressants: are neurotrophins involved?
Authors: Rybakowski Janusz K. , Permoda‐Osip Agnieszka , Skibinska Maria , Adamski Rafal , Bartkowska‐Sniatkowska Alicja 
Published: November 2012

ObjectivesWe investigated serum brain‐derived neurotrophin factor (BDNF), nerve growth factor (NGF), neurotrophin‐3 (NTF3), neurotrophin‐4 (NTF4) and the glial‐derived neurotrophic factor (GDNF), in relation to ketamine efficacy, in bipolar depressed patients resistant to treatment with antidepressants.MethodsTwenty‐five patients (4 male, 21 female), aged 27–67 years, with bipolar depression, receiving mood‐stabilizing medications, were studied. Antidepressants were discontinued for at least 7 days before single intravenous ketamine infusion (0.5 mg/kg body weight). Response to ketamine was defined as ≥50% reduction on 17‐item Hamilton Depression Rating Scale (HDRS) after 1 week, and remission as HDRS score ≤7. Serum BDNF, NGF, NTF3, NTF4 and GDNF levels were estimated by enzyme‐linked immunosorbent assay.ResultsThere were 13 ketamine responders and 12 non‐responders. The remission was obtained in eight and 12 patients after seven and 14 days, respectively. At baseline, there were no differences between responders and non‐responders in any of the neurotrophins. Serum BDNF was significantly reduced after 7 days in non‐responders. Serum NGF, NT3, NT4 and GDNF did not significantly change.ConclusionsThe results confirm an antidepressant effect of ketamine infusion as an add‐on to mood‐stabilizing drugs in bipolar depression resistant to antidepressant treatment. They may also suggest a possible involvement of BDNF in this effect. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of atypical antipsychotics on antioxidant enzyme activities in human erythrocytes (in vitro study)
Authors: Miljević Čedo , Nikolić‐Kokić Aleksandra , Nikolić Milan , Niketić Vesna , Spasić Mihajlo B. , Lečić‐Toševski Dušica , Blagojević Duško 
Published: November 2012

ObjectiveThis study was set out to examine the impact of atypical antipsychotic drugs: aripiprazole, clozapine, ziprasidone, olanzapine, quetiapine, sertindole and amisulpride on the activity of antioxidant defence enzymes in human erythrocytes in vitro.MethodsCu,Zn‐superoxide dismutase (SOD1), catalase (CAT), selenium‐dependent glutathione peroxidase and glutathione reductase activities were determined after drugs incubation with blood of 15 apparently healthy non‐smoking male volunteers (ages 23–39) for 1 h at 37 °C.ResultsA statistically significant increase in SOD1 activity was found in samples incubated with aripiprazole (p < 0.01) and quetiapine (p < 0.05) compared with incubated control. SOD1 activity profile following native polyacrylamide gel electrophoresis indicates that aripiprazole and quetiapine protect enzyme activity from inhibition with hydrogen peroxide. Our results showed that sertindole decreases activity of CAT comparing with control non‐treated erythrocytes. Moreover, in sertindole treated erythrocytes, negative correlation between SOD1 and glutathione peroxidase activities was found. Increased amount of hydrogen peroxide in such situation may leave erythrocytes and transform their role in circulation from anti‐oxidative to pro‐oxidative.ConclusionsOur results indicate that mechanism through sertindole could express its in vivo toxic effects and point toward possible (neuro)protective effects of aripiprazole and quetiapine. Copyright © 2012 John Wiley & Sons, Ltd.
New functions of protein kinase Gcn2 in yeast and mammals
Authors: Murguía José R. , Serrano Ramón 
Published: November 2012

AbstractThe classical role of the conserved Gcn2 kinase of yeast and mammals is to activate the translation of the transcription factors Gcn4 in yeast and activating transcription factor 4 in mammals by phosphorylating the eukaryotic translation initiation factor 2α. Gcn2 is activated by uncharged tRNAs in response to amino acid starvation and this regulatory system is important for tolerance to nutrient deprivation and other stresses and for development, differentiation, and normal function of mammalian organs. In the past few years, the classical Gcn2 pathway has been shown to modulate life span, tumor cell survival, and immune responses. In addition, Gcn2 modulates translation of novel mRNAs such as those of an unknown regulator of leucine transport and of sulfiredoxin SRX1 in yeast (activation of translation) and of inducible nitric oxide synthase, ErBb2, HIF1a, and 5′‐terminal oligopyrimidine tract mRNAs in mammals (inhibition of translation). Finally, Gcn2 directly phosphorylates novel proteins such as methionyl‐tRNA synthetase in mammals, and this triggers a pathway for DNA repair. These findings anticipate many expanding roles of Gcn2 in the future, with relevance for stress responses and human disease. © 2012 IUBMB IUBMB Life, 64(12): 971–974, 2012
Toxicity of Engineered Nanomaterials: A Physicochemical Perspective
Authors: Podila Ramakrishna , Brown Jared M. 
Published: November 2012

ABSTRACTThe global market for nanomaterial‐based products is forecasted to reach 100 billion dollars per annum for 2011–2015. Extensive manufacturing and the use of engineered nanomaterials have raised concerns regarding their impact on biological response in living organisms and the environment at large. The fundamental properties of nanomaterials exhibit a complex dependence upon several factors such as their morphology, size, defects, and chemical stability. Therefore, it is exceedingly difficult to correlate their biological response with their intricate physicochemical properties. For example, varying toxic response may ensue due to different methods of nanomaterial preparation, dissimilar impurities, and defects. In this review, we surveyed the existing literature on the dependence of cytotoxicity on physicochemical properties. We found that ENM size, shape, defect density, physicochemical stability, and surface modification to be the main causes that elicit altered physiological response or cytotoxicity. © 2012 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:50‐55, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.21442