bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thiols Screened by the Neocarzinostatin Protein for Preserving or Detoxifying its Bound Enediyne Antibiotic
Authors: Chi Hung‐Wen , Huang Chun‐Chi , Chin Der‐Hang 
Published: April 2012

AbstractNeocarzinostatin is an antibiotic chromoprotein produced by Streptomyces carzinostaticus. Its enediyne‐containing chromophore exhibits high DNA cleavage activity and belongs to one of the most potent categories of antitumor agents. The labile chromophore is readily inactivated by environmental thiols including the most abundant glutathione. How the microorganism preserves the secreted antibiotic and at the same time is immune to its toxicity are of interest. Site‐directed mutagenesis studies of the neocarzinostatin protein have shown that residues D33 and D99 play primary and secondary roles, respectively, in preserving neocarzinostatin from acidic glutathione whereas D79 and other residues around the opening of the binding cleft have an insignificant effect. Biothiol analyses revealed that cells of S. carzinostaticus produced no glutathione, but instead neutral mycothiol, which is known to serve functions analogous to glutathione. Mycothiol was the only neutral‐charged thiol produced by the organism; all other identified biothiols carried at least partial negative charges. When the bacteria were cultured under conditions that stimulated the biosynthesis of neocarzinostatin, the yield of mycothiol increased significantly, which suggests mycothiol‐dependent cellular detoxification. Treating neocarzinostatin samples with the cell extract that retained active sulfhydryls led to efficient drug inactivation, which indicates that mycothiol is allowed to approach the protein‐bound chromophore. The anionic side‐chains of D33 and D99 in the neocarzinostatin protein played two critical roles in a single thiol‐screening operation: Preserving the antibiotic for defense and survival by rejecting the ubiquitous glutathione through charge–charge repulsion in the outer‐cell environment and detoxifying the toxin in the inner‐cell body for self‐resistance by accepting the cell‐produced neutral mycothiol.
Archipelago architecture of the focal adhesion: Membrane molecules freely enter and exit from the focal adhesion zone
Authors: Shibata Akihiro C. E. , Fujiwara Takahiro K. , Chen Limin , Suzuki Kenichi G. N. , Ishikawa Yoshiro , Nemoto Yuri L. , Miwa Yoshihiro , Kalay Ziya , Chadda Rahul , Naruse Keiji , Kusumi Akihiro 
Published: April 2012

AbstractThe focal adhesion (FA) is an integrin‐based structure built in/on the plasma membrane, mechanically linking the extracellular matrix with the termini of actin stress fibers, providing key scaffolds for the cells to migrate in tissues. The FA was considered as a micron‐scale, massive assembly of various proteins, although its formation and decomposition occur quickly in several to several 10 s of minutes. The mechanism of rapid FA regulation has been a major mystery in cell biology. Here, using fast single fluorescent‐molecule imaging, we found that transferrin receptor and Thy1, non‐FA membrane proteins, readily enter the FA zone, diffuse rapidly there, and exit into the bulk plasma membrane. Integrin β3 also readily enters the FA zone, and repeatedly undergoes temporary immobilization and diffusion in the FA zone, whereas approximately one‐third of integrin β3 is immobilized there. These results are consistent with the archipelago architecture of the FA, which consists of many integrin islands: the membrane molecules enter the inter‐island channels rather freely, and the integrins in the integrin islands can be rapidly exchanged with those in the bulk membrane. Such an archipelago architecture would allow rapid FA formation and disintegration, and might be applicable to other large protein domains in the plasma membrane. © 2012 Wiley Periodicals, Inc
Anatomical basis of sun compass navigation I: The general layout of the monarch butterfly brain
Authors: Heinze Stanley , Reppert Steven M. 
Published: April 2012

AbstractThe eastern North American monarch butterfly (Danaus plexippus) is well known for its long‐distance fall migration. To illuminate the neural basis of sun compass navigation during the migration, the layout of the monarch butterfly brain was analyzed by immunocytochemistry and three‐dimensional reconstructions. The monarch brain is depicted in anti‐synapsin‐labeled serial sections (grayscale images), as well as a three‐dimensional reconstruction (color image). The Journal of Comparative Neurology, Volume 520, Number 8, pages 1599–1628.
Development of tyrosine hydroxylase‐immunoreactive cell populations and fiber pathways in the brain of the dogfish Scyliorhinus canicula: New perspectives on the evolution of the vertebrate catecholaminergic system
Authors: Carrera Iván , Anadón Ramón , Rodríguez‐Moldes Isabel 
Published: April 2012

AbstractDevelopmental studies of the central catecholaminergic (CA) system are essential for understanding its evolution. To obtain knowledge about the CA system in chondrichthyans, an ancient gnathostome group, we used immunohistochemical techniques for detecting tyrosine hydroxylase (TH), the initial rate‐limiting enzyme of the CA synthesis, to study: 1) the neuromery of developing TH‐immunoreactive (ir) neuronal populations, 2) the development of TH‐ir innervation, and 3) the organization of TH‐ir cells and fibers in the brain of postembryonic stages of the shark Scyliorhinus canicula. The first TH‐ir cells appeared in the hypothalamus and rostral diencephalon (suprachiasmatic, posterior recess and posterior tubercle nuclei at embryonic stage 26, and dorsomedial hypothalamus at stage 28); then in more caudal basal regions of the diencephalon and rostral mesencephalon (substantia nigra/ventral tegmental area); and later on in the anterior (locus coeruleus/nucleus subcoeruleus) and posterior (vagal lobe and reticular formation) rhombencephalon. The appearance of TH‐ir cells in the telencephalon (pallium) was rather late (stage [S]31) with respect to the other TH‐ir prosencephalic populations. The first TH‐ir fibers arose from cells of the posterior tubercle (S30) and formed recognizable ascending (toward dorsal and rostral territories) and descending pathways at S31. When the second half of embryonic development started (S32), TH‐ir fibers innervated most brain areas, and nearly all TH‐ir cell groups of the postembryonic brain were already established. This study provides key information about the evolution of the developmental patterns of central CA systems in fishes and thus may help in understanding how the vertebrate CA systems have evolved. J. Comp. Neurol. 520:3574–3603, 2012. © 2012 Wiley Periodicals, Inc.
Phox2b expression in the taste centers of fish
Authors: Coppola Eva , D'autréaux Fabien , Nomaksteinsky Marc , Brunet Jean‐François 
Published: April 2012

AbstractThe homeodomain transcription factor Phox2b controls the formation of the sensory‐motor reflex circuits of the viscera in vertebrates. Among Phox2b‐dependent structures characterized in rodents is the nucleus of the solitary tract, the first relay for visceral sensory input, including taste. Here we show that Phox2b is expressed throughout the primary taste centers of two cyprinid fish, Danio rerio and Carassius auratus, i.e., in their vagal, glossopharyngeal, and facial lobes, providing the first molecular evidence for their homology with the nucleus of the solitary tract of mammals and suggesting that a single ancestral Phox2b‐positive neuronal type evolved to give rise to both fish and mammalian structures. In zebrafish larvae, the distribution of Phox2b+ neurons, combined with the expression pattern of Olig4 (a homologue of Olig3, determinant of the nucleus of the solitary tract in mice), reveals that the superficial position and sheet‐like architecture of the viscerosensory column in cyprinid fish, ideally suited for the somatotopic representation of oropharyngeal and bodily surfaces, arise by radial migration from a dorsal progenitor domain, in contrast to the tangential migration observed in amniotes. J. Comp. Neurol. 520:3633–3649, 2012. © 2012 Wiley Periodicals, Inc.
Anatomical plasticity in the adult zebra finch song system
Authors: McDonald Kathryn S. , Kirn John R. 
Published: April 2012

AbstractIn many songbirds, vocal learning‐related cellular plasticity was thought to end following a developmental critical period. However, mounting evidence in one such species, the zebra finch, suggests that forms of plasticity common during song learning continue well into adulthood, including a reliance on auditory feedback for song maintenance. This reliance wanes with increasing age, in tandem with age‐related increases in fine motor control. We investigated age‐related morphological changes in the adult zebra finch song system by focusing on two cortical projection neuron types that 1) share a common efferent target, 2) are known to exhibit morphological and functional change during song learning, and 3) exert opposing influences on song acoustic structure. Neurons in HVC and the lateral magnocellular nucleus of the anterior nidopallium (LMAN) both project to the robust nucleus of the arcopallium (RA). During juvenile song learning and adult song maintenance, HVC promotes song syllable stereotypy, whereas LMAN promotes learning and acoustic variability. After retrograde labeling of these two cell types in adults, there were age‐related increases in dendritic arbor in HVC‐RA but not LMAN‐RA neurons, resulting in an increase in the ratio of HVC‐RA:LMAN‐RA dendritic arbor. Differential growth of HVC relative to LMAN dendrites may relate to increases in song motor refinement, decreases in the reliance of song on auditory feedback, or both. Despite this differential growth with age, both cell types retain the capacity for experience‐dependent growth, as we show here. These results may provide insights into mechanisms that promote and constrain adult vocal plasticity. J. Comp. Neurol. 520:3673–3686, 2012. © 2012 Wiley Periodicals, Inc.
A trust management model for service‐oriented distributed networks
Authors: Yu Yanli , Li Keqiu , Jin Yingwei , Zhang Yong 
Published: April 2012

SUMMARYThe service‐oriented distributed network requires more stable and persistent services, but the services from dishonest or unstable nodes would damage the correctness and availability of services. To efficiently obtain the services from high dependable nodes, many trust management systems have been developed. However, the previous trust models in distributed networks ignore a fact that the entity itself could provide trust information for services also. In this paper, we present a novel trust management model based on the subjective logic trust for service‐oriented distributed networks. The proposed algorithm involves passive trust of entity and combines the direct trust and recommendation trust. We also propose a novel scheme called passive trust feedback to avoid the deceit of malicious nodes and unstable nodes, and to encourage honest nodes. Our proposed model expands the trust range of service resource via passive trust of entity, which generates a flexible access path to the service resources. Simulations show that the proposed trust management model can significantly improve the feasibility of trust management as well as effectively detect malicious entities. Copyright © 2012 John Wiley & Sons, Ltd.
Determination of the Static Zero‐Field Splitting of Gd3+ Complexes in Solution from the Shifts of the Central Magnetic Fields of Their EPR Spectra
Authors: Fries Pascal H. , Belorizky Elie 
Published: April 2012

AbstractIn principle, the Redfield theory of EPR spectra applies only to fast‐rotating complexes with rather small static zero‐field splitting (ZFS) terms. However, at sufficiently high frequencies, typically of 35 GHz and above, it predicts values of the central magnetic fields which are surprisingly accurate well beyond its expected applicability range. This remarkable feature is demonstrated by showing that the Redfield EPR spectrum crosses its baseline at the same point as its “exact” simulated counterpart. It is shown that the shift of the central magnetic field with respect to its limiting value in the absence of ZFS terms is often simply proportional to the square of the magnitude of the static ZFS term divided by the spectrometer frequency. This property is used to determine the magnitude of the static ZFS term independently of its fluctuation dynamics and of the presence of the transient ZFS term.
Noncomputability, unpredictability, and financial markets
Authors: Graça Daniel S. 
Published: April 2012

AbstractOne of the most significant achievements from theoretical computer science was to show that there are noncomputable problems, which cannot be solved through algorithms. Although the formulation of such problems is mathematical, they often can be interpreted as problems derived from other fields, like physics or computer science. However, no non‐computable problem with economical or financial inspiration has been presented before. Here, we study the problem of valuation: given some adequate data, find the value of an asset. Valuation is modeled mathematically by the discounted cash flow operator. We show, using surprisingly simple arguments, that this operator is not computable. As theoretically, financial markets should trade assets based on their fair value, our result suggests that unpredictability of such markets may partially stem from inherent noncomputable behavior. A discussion of this result is also included. © 2012 Wiley Periodicals, Inc. Complexity, 2012
Interpersonal Psychotherapy in Child and Adolescent Mental Health Services
Authors: Morris Jane 
Published: April 2012

Over the past two decades, Interpersonal Psychotherapy (IPT) has shown itself to be one of only two evidence‐based psychotherapies for the treatment of depression in adolescence—an age group where the prescribing of antidepressant medication is limited and where morbidity and recurrence are high. We review the literature on the development and research studies of the IPT model for depressed adolescent patients, as well as recent developments expanding its use to other cultures and different diagnostic areas. An overview is provided of the model in action, using a fictionalized case vignette. Finally, we consider the future of IPT for the treatment and prevention of affective disorders in the under 18 age group and in the context of other generations in vulnerable families. Copyright © 2012 John Wiley & Sons, Ltd.Key Practitioner Message

Interpersonal Psychotherapy is one of only two evidence‐based therapies for the treatment of depression in adolescents, providing an acceptable and often enjoyable alternative to cognitive–behavioural therapy for both patients and their therapists.
For experienced clinicians, IPT accreditation can be achieved after a basic 4‐ to 5‐day course, followed by formal supervision of 2–4 cases.
The model emphasizes ‘sick role’—healthy and responsible ways to behave as a recovering patient.
Interpersonal Psychotherapy is not only compatible with—and may support—prescription of antidepressant medication but may also be used where medication is best avoided, such as during teenage pregnancy.
The systemic perspective allows flexible inclusion of parents and other significant members of the network whilst respecting the young person's autonomy and not requiring the orchestration and extra resource of formal family therapy models.
ATP‐binding cassette (ABC) transporter expression and localization in sea urchin development
Authors: Shipp Lauren E. , Hamdoun Amro 
Published: April 2012

AbstractBackground: ATP‐binding cassette (ABC) transporters are membrane proteins that regulate intracellular concentrations of myriad compounds and ions. There are >100 ABC transporter predictions in the Strongylocentrotus purpuratus genome, including 40 annotated ABCB, ABCC, and ABCG “multidrug efflux” transporters. Despite the importance of multidrug transporters for protection and signaling, their expression patterns have not been characterized in deuterostome embryos. Results: Sea urchin embryos expressed 20 ABCB, ABCC, and ABCG transporter genes in the first 58 hr of development, from unfertilized egg to early prism. We quantified transcripts of ABCB1a, ABCB4a, ABCC1, ABCC5a, ABCC9a, and ABCG2b, and found that ABCB1a mRNA was 10–100 times more abundant than other transporter mRNAs. In situ hybridization showed ABCB1a was expressed ubiquitously in embryos, while ABCC5a was restricted to secondary mesenchyme cells and their precursors. Fluorescent protein fusions showed localization of ABCB1a on apical cell surfaces, and ABCC5a on basolateral surfaces. Conclusions: Embryos use many ABC transporters with predicted functions in cell signaling, lysosomal and mitochondrial homeostasis, potassium channel regulation, pigmentation, and xenobiotic efflux. Detailed characterization of ABCB1a and ABCC5a revealed that they have different temporal and spatial gene expression profiles and protein localization patterns that correlate to their predicted functions in protection and development, respectively. Developmental Dynamics 241:1111–1124, 2012. © 2012 Wiley Periodicals, Inc.
Species‐rich ecosystems are vulnerable to cascading extinctions in an increasingly variable world
Authors: Kaneryd Linda , Borrvall Charlotte , Berg Sofia , Curtsdotter Alva , Eklöf Anna , Hauzy Céline , Jonsson Tomas , Münger Peter , Setzer Malin , Säterberg Torbjörn , Ebenman Bo 
Published: April 2012

AbstractGlobal warming leads to increased intensity and frequency of weather extremes. Such increased environmental variability might in turn result in increased variation in the demographic rates of interacting species with potentially important consequences for the dynamics of food webs. Using a theoretical approach, we here explore the response of food webs to a highly variable environment. We investigate how species richness and correlation in the responses of species to environmental fluctuations affect the risk of extinction cascades. We find that the risk of extinction cascades increases with increasing species richness, especially when correlation among species is low. Initial extinctions of primary producer species unleash bottom‐up extinction cascades, especially in webs with specialist consumers. In this sense, species‐rich ecosystems are less robust to increasing levels of environmental variability than species‐poor ones. Our study thus suggests that highly species‐rich ecosystems such as coral reefs and tropical rainforests might be particularly vulnerable to increased climate variability.
Tris(phosphonomethyl) Cyclen Derivatives: Synthesis, Acid–Base Properties and Complexation Studies with Cu2+ and Zn2+ Ions
Authors: Lima Luís M. P. , Esteves Catarina V. , Delgado Rita , Hermann Petr , Kotek Jan , Ševčíková Romana , Lubal Přemysl 
Published: April 2012

AbstractThree compounds that are based on cyclen and contain three methylphosphonate pendant arms ― (1,4,7,10‐tetraazacyclododecane‐1,4,7‐triyl)tris(methylene)triphosphonic acid (H6do3p), 3‐{4,7,10‐tris[(dihydroxyphosphoryl)methyl]‐1,4,7,10‐tetraazacyclododecan‐1‐yl}propanoic acid (H7do3p1pr) and [10‐(3‐hydroxypropyl)‐1,4,7,10‐tetraazacyclododecane‐1,4,7‐triyl]tris(methylene)triphosphonic acid (H6do3p1ol) ― were synthesized and characterized. X‐ray crystal structures were determined for H6do3p and for the complex [Cu(H2O)6]2+[Cu(H2O)(H4dotp)]2– of a related ligand H8dotp [H8dotp = (1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetrayl)tetrakis(methylene)tetraphosphonic acid]. They show the copper(II) centre coordinated only to the four amines of the macrocycle and one water molecule in the apical position. The acid–base properties of the three compounds were studied in aqueous solution by potentiometry and 31P NMR spectroscopy. All ligands exhibit very high basicity and their protonation schemes are dominated by proton relocations between the basic sites and intramolecular hydrogen bonding. The thermodynamic stability constants for complexes of the three ligands with Cu2+ and Zn2+ metal ions were determined by potentiometry and exhibit very high values for the complexes of Cu2+. UV/Vis spectroscopy was used to assess the acid‐assisted dissociation of the Cu2+ complexes and showed that the dissociation rates are faster than for the corresponding complex of H8dotp, whereas the [Cu(do3p1ol)]4– complex is the most inert one in this series.
Binuclear Arylnickel Complexes with Bridging Bis(arylimino)‐1,4‐pyrazine Ligands
Authors: Klein Axel , Biewer Christian , Hamacher Claudia , Hurkes Natascha , Perez Outeiral Jessica , Paniagua Erik Mora , Schmieder Ann‐Kathrin , Schüren Andreas O. , Burma Prabhakara Rao , Ciszewski James T. , Vicic David A. 
Published: April 2012

AbstractBinuclear organometallic nickel complexes of the type [(μ‐NN){Ni(Mes)Br}2] {NN = α‐diimine chelate ligand of the type 2,5‐bis[1‐(aryl)iminoethyl]pyrazine; Mes = mesityl = 2,4,6‐trimethylphenyl} have been prepared and characterised electrochemically and spectroscopically in detail. A combination of NMR spectroscopy and quantum chemical calculations allowed the assignment of stereoisomers and their relative stability. The long‐wavelength absorptions (600–1000 nm) assignable to charge‐transfer transitions reveal a marked electronic coupling of the two metal centres over the ligand bridge via their low‐lying π* orbitals. The reversible reductive electrochemistry yields stable radical anionic complexes with mainly ligand‐centred spin density as shown by electron paramagnetic resonance (EPR) spectroscopy and UV/Vis spectroelectrochemistry of the free ligands and their nickel complexes in combination with DFT calculations. Preliminary investigations of the complexes as catalysts in Negishi cross‐coupling reactions gave promising results.
2,1,3‐Benzothiadiazole‐Modified DNA
Authors: Garo Florian , Häner Robert 
Published: April 2012

AbstractThe use of 2,1,3‐benzothiadiazole (BTD) as a structural element with advanced electronic properties for DNA hybrids is described. Bis(alkynyl)‐ and bis(carboxamide)‐derived BTD units are shown to support duplex stability through interstrand stacking interactions. Placement of the BTD units opposite to a natural base, however, leads to considerable destabilization. The bis(alkynyl)‐derived BTD W is strongly fluorescent, and quantum yields of up to 0.20 are observed. Its fluorescence behavior is strongly dependent on the neighboring nucleobases. The quenching effect of the natural bases decreases in the order G >> A ≥ T ≥ C and correlates very well with the free energies for charge separation (ΔGCS) through photoinduced electron transfer, as calculated by the Rehm–Weller equation. Fluorescence of W is completely quenched when it is placed against the bis(carboxamide)‐derived BTD V. The described BTD‐based compounds W and V represent valuable building blocks for the construction of highly ordered, DNA‐based materials with special optical and electronic properties.