bluuebunny/crossref_metadata_2025 huggingface dataset:
Label-Free Screening of Drug—Protein Interactions by Time-Resolved Fourier Transform Infrared Spectroscopic Assays Exemplified by Ras Interactions
Authors: Kötting Carsten , Suveyzdis Yan , Bojja Ravi S. , Metzler-Nolte Nils , Gerwert Klaus
Published: October 2010

Time-resolved Fourier transform infrared (FT-IR) spectroscopy can reveal molecular details of protein interactions. Analysis of difference spectra selects the absorptions of respective protein groups involved in an interaction against the background of the whole sample. By comparison of the same difference spectrum with and without a small molecule, one can determine whether the small molecule interferes with the protein or not. Usually a marker band of a specific residue of the protein is monitored. Here, we show three different time-resolved FT-IR assays detecting interactions of potential small molecules for molecular therapy with the GTPase Ras as an example for small GTPase binding proteins. Ras regulates signal transduction processes through a switching mechanism, cycling between an active “on” GTP-bound form and an inactive “off” GDP-bound state. Molecular defects in Ras can impair the ability of Ras and the Ras–RasGAP complex to hydrolyze GTP, contributing to uncontrolled cell growth and cancer. Oncogenic mutated Ras is found in about 30% of all cancer cells. We show in vitro assays, indicating (I) the shift of Ras into its “off” conformation, which inhibits the Ras pathway; (II) down-regulation of Ras signaling by changes in the Ras–Raf effector interaction; and (III) down-regulation of Ras signaling pathway by catalyzing GTP hydrolysis. Since almost all molecules have characteristic marker bands in the infrared, time-resolved FT-IR spectroscopy can be used label-free. No artificial nucleotides that could influence the interaction are needed. Both, sample preparation and evaluation can be automated in order to allow for high-throughput screening.
Transient Vibrational Echo versus Transient Absorption Spectroscopy: A Direct Experimental and Theoretical Comparison
Authors: Baiz Carlos R. , McCanne Robert , Kubarych Kevin J.
Published: October 2010

Transient dispersed vibrational echo (DVE) spectroscopy is a practical alternative to transient-absorption spectroscopy because it affords increased sensitivity as well as greater signal-to-noise ratio without the need to detect a reference spectrum. However, as a third-order nonlinear probe, the extraction of kinetic information from transient-DVE is somewhat cumbersome compared to transient absorption. This article provides a direct experimental and theoretical comparison between transient-absorption and transient-DVE measurements and presents a framework for analyzing kinetic measurements while exploring the implications of making some simplifying assumptions in the data analysis. The equations for computing the signal-to-noise ratios under different experimental conditions are derived and used in the analysis of the experimental data. The results, obtained under the same experimental conditions, show that for a relatively strong terminal carbonyl stretching mode, signal-to-noise ratios in transient-DVE spectroscopy are approximately 2.5 times greater than transient absorption. The experimental results along with the theoretical models indicate that transient-DVE could become an attractive alternative to transient-absorption spectroscopy for measuring the kinetics of light-induced processes.
Teaching, Learning, and Using Spectroscopy with Commercial, Off-the-Shelf Technology
Authors: Scheeline Alexander
Published: October 2010

The astonishing propagation of sophisticated electronics across the globe has attracted the attention of many for developing disease diagnoses, water purity measurements, and security applications using cellular telephones and the complementary metal oxide semiconductor (CMOS) cameras with which many are equipped. This Focal Point article builds on the theme of using technology already in the hands of students/consumers to teach spectrophotometry and, by extension, to suggest how one might inexpensively develop an instrumental analysis curriculum at extraordinarily low cost. A grating spectrophotometer using a white light-emitting diode (LED) light source, plastic sample cuvette, holographic transmission grating, and any camera that produces JPG files as output is described. Optical characteristics are explained and a sample working curve provided. The raw data for that curve are available as Supplementary Material on-line. The behavior of the “Cell Phone Spectrometer” is inadequate for routine analysis but outstanding for teaching the workings of optical instrumentation components and systems.
What is the Origin of Positional Fluctuation of Spectral Features: True Frequency Shift or Relative Intensity Changes of Two Overlapped Bands?
Authors: Ryu Soo Ryeon , Noda Isao , Jung Young Mee
Published: October 2010

We investigated what is really meant by so-called positional or frequency fluctuation of spectral features. To show the difference between the true frequency shift of a single band and apparent peak maximum shift caused by relative intensity changes of overlapped adjacent bands, we analyzed infrared (IR) spectra of the OH stretching band of ethylene glycol during the heating process and the C=O stretching band of acetone in a mixed solvent CHCl3/CCl4 with varying solvent compositions. These spectra are well-known examples of so-called “band shift” phenomena often interpreted as the manifestation of gradual changes in the IR frequency associated with a specific chemical bond under the influence of molecular interactions. Analyses of IR spectra showed that the apparent positional shifts of peak maxima in these systems are actually due to relative contribution changes of two overlapped bands, instead of the gradual frequency shift of a single band induced by the change in the strength of molecular interactions. To further clarify our interpretation of “peak maximum shifts”, we also analyzed simulated spectral datasets, comparing the true band frequency shift and change in the relative contributions of overlapped bands. It was found that principal component analysis (PCA) is a surprisingly sensitive tool to distinguish the two possible mechanisms of peak maximum shift. The new insight revealed by this study should help the interpretation of molecular interactions probed by vibrational spectroscopy.
Dielectric Properties of Water in Butter and Water—AOT—Heptane Systems Measured Using Terahertz Time-Domain Spectroscopy
Authors: Møller Uffe , Folkenberg Jacob Riis , Jepsen Peter Uhd
Published: October 2010

We investigate the dielectric properties of water confined in nanometer-sized inverse micelles in mixtures of water, AOT, and heptane. We show that the dielectric properties of the confined water are dependent on the water pool size and different from those of bulk water. We also discuss the dielectric properties of different vegetable oils, lard, and butter, and use these properties to deduce the dielectric properties of water in butter, which are shown to deviate significantly from the dielectric properties of bulk water.
Characterization of a Variable Angle Reflection Fourier Transform Infrared Accessory Modified for Surface Plasmon Resonance Spectroscopy
Authors: Menegazzo Nicola , Kegel Laurel L. , Kim Yoon-Chang , Booksh Karl S.
Published: October 2010

The Harrick AutoSeagull variable angle reflection accessory for Fourier transform infrared (FT-IR) spectrometers provides access to various spectroscopic techniques in a highly flexible platform. In particular, its ability to perform total internal reflection measurements is of interest because it also forms the basis for surface plasmon resonance (SPR) spectroscopy in prism-based configurations. The work presented here discusses the modification of the AutoSeagull to perform SPR spectroscopy, allowing for easy incorporation of the technique into most common FT-IR spectrometers. The wavelength dependency of the dielectric constant of the plasmon-supporting metal (in our case, gold) is largely responsible for the sensitivity attributed to changes in the sample's refractive index (RI) monitored by SPR spectroscopy. Furthermore, the optical properties of gold are such that when near-infrared (NIR) and/or mid-infrared (mid-IR) wavelengths are used to excite surface plasmons, higher sensitivities to RI changes are experienced compared to surface plasmons excited with visible wavelengths. The result is that in addition to instrumental simplicity, SPR analysis on FT-IR spectrometers, as permitted by the modified AutoSeagull, also benefits from the wavelength ranges accessible. Adaptation of the AutoSeagull to SPR spectroscopy involved the incorporation of slit apertures to minimize the angular spread reaching the detector, resulting in sharper SPR “dips” but at the cost of noisier spectra. In addition, discussion of the system's analytical performance includes comparison of dip quality as a function of slit size, tailoring of the dip minima location with respect to incident angle, and sensitivity to bulk RI changes.
Numerical Correction of Detector Channel Cross-Talk Using Full-Spectrum Fluorescence Correlation Spectroscopy
Authors: Roach Carol A. , Neal Sharon L.
Published: October 2010

Fluorescence correlation spectroscopy (FCS) uses fluctuations in the fluorescence collected from a small illuminated volume to measure dynamic processes of fluorophores. In traditional FCS, spectral overlap produces cross-talk in dedicated detector channels, undermining the accuracy of measurements of molecular interactions. Here, the experimental realization of full-spectrum fluorescence correlation spectroscopy is described and coupled with multivariate data analysis to numerically correct detector cross-talk, isolating spectra and fluctuation traces of mixture components in spite of overlap. Application of this methodology is illustrated using the measurement of the diffusion constant of labeled polystyrene in hydroxypropyl cellulose in the presence of a persistent dye. Additionally, the results show that full-spectrum FCS with multivariate analysis can isolate and characterize signals from unanticipated sample components.
Interactions of Vitamin K3 with Herring-Sperm DNA Using Spectroscopy and Electrochemistry
Authors: Huang Jianhang , Wang Xingming , Fei Dan , Ding Lisheng
Published: October 2010

By means of ultraviolet-visible (UV-Vis) and fluorescence spectra, the binding ratio between vitamin K3 and herring-sperm DNA in a physiological pH environment (pH = 7.40) was determined as nK3: nDNA = 2:1, and the binding constants of vitamin K3 binding to DNA at different temperatures were determined as Kθ298K = 1.28 × 105 L.mol−1 and Kθ310K = 7.19 × 104 L.mol−1, which were confirmed using the double reciprocal method are Δr Hmθ = −3.57 × 104 J.mol−1, Δr Gmθ = −2.92 × 104 J.mol−1, and Δr Smθ = 217.67 J.mol−1K−1. The driving power of this process was enthalpy. An intercalation binding of the vitamin K3 with DNA was supported by a competitive experiment using acridine orange (AO) as a spectral probe. By combination analysis of the Scatchard method and cyclic voltammetry, we suggested that the interaction mode between vitamin K3 and herring-sperm DNA would be a mixed mode. The quinonoid, duality fused-ring of vitamin K3 can intercalate into the base pairs of DNA, and there is an electrostatic binding along with intercalation binding.
Nondestructive Assessment of Engineered Cartilage Constructs Using Near-Infrared Spectroscopy
Authors: Baykal Doruk , Irrechukwu Onyi , Lin Ping-Chang , Fritton Kate , Spencer Richard G. , Pleshko Nancy
Published: October 2010

Noninvasive assessment of engineered cartilage properties would enable better control of the developing tissue towards the desired structural and compositional endpoints through optimization of the biochemical environment in real time. The objective of this study is to assess the matrix constituents of cartilage using near-infrared spectroscopy (NIRS), a technique that permits full-depth assessment of developing engineered tissue constructs. Mid-infrared (mid-IR) and NIR data were acquired from full-thickness cartilage constructs that were grown up to 4 weeks with and without mechanical stimulation. Correlations were assessed between established mid-IR peak areas that reflect the relative amount of collagen (amide I, amide II, and 1338 cm−1) and proteoglycan (PG), (850 cm−1), and the integrated area of the NIR water absorbance at 5190 cm−1. This analysis was performed to evaluate whether simple assessment of the NIR water absorbance could yield information about matrix development. It was found that an increase in the mid-IR PG absorbance at 850 cm−1 correlated with the area of the NIR water peak (Spearman's rho = 0.95, p < 0.0001). In the second analysis, a partial least squares method (PLS1) was used to assess whether an extended NIR spectral range (5400–3800 cm−1) could be utilized to predict collagen and proteoglycan content of the constructs based on mid-IR absorbances. A subset of spectra was randomly selected as an independent prediction set in this analysis. Average of the normalized root mean square errors of prediction of first-derivative NIR spectral models were 7% for 850 cm−1 (PG), 11% for 1338 cm−1 (collagen), 8% for amide II (collagen), and 8% for amide I (collagen). These results demonstrate the ability of NIRS to monitor macromolecular content of cartilage constructs and is the first step towards employing NIR to assess engineered cartilage in situ.
Sensitive Chemiluminescence Determination of Thirteen Cephalosporin Antibiotics with Luminol—Copper(II) Reaction
Authors: Du Jianxiu , Li Hong
Published: October 2010

A new chemiluminescence reaction, the luminol-Cu2+ reaction, was investigated for the determination of thirteen (13) cephalosporin antibiotics, namely cefalexin, cefadroxil, cefradine, cefazolin sodium, cefaclor, cefuroxime axetil, cefotaxime sodium, cefoperazone sodium, ceftriaxone sodium, ceftazidime, cefetamet pivoxil hydrochloride, cefixime, and cefpodoxime. It was found that, without adding any special oxidant, strong chemiluminescent (CL) signal could be produced from the reaction of the alkaline luminol with the above-mentioned antibiotics in the presence of Cu2+. The experimental conditions for the reaction were carefully optimized with flow-injection mode. The detection limits are 0.3 ng/mL cefalexin, 3 ng/mL cefadroxil, 0.3 ng/mL cefradine, 0.02 μg/mL cefazolin sodium, 0.8 ng/mL cefaclor, 0.02 μg/mL cefuroxime axetil, 5 ng/ mL cefotaxime sodium, 0.02 μg/mL cefoperazone sodium, 0.8 ng/mL ceftriaxone sodium, 1 ng/mL ceftazidime, 0.08 ng/mL cefetamet pivoxil hydrochloride, 0.8 ng/mL cefixime, and 2 ng/mL cefpodoxime. The proposed method was validated by direct application to commercial formulations and spiked milk samples containing cefradine. A possible reaction mechanism is also discussed.
Association of Indigo with Zeolites for Improved Color Stabilization
Authors: Dejoie Catherine , Martinetto Pauline , Dooryhée Eric , Elslande Elsavan , Blanc Sylvie , Bordat Patrice , Brown Ross , Porcher Florence , Anne Michel
Published: October 2010

The durability of an organic color and its resistance against external chemical agents and exposure to light can be significantly enhanced by hybridizing the natural dye with a mineral. In search for stable natural pigments, the present work focuses on the association of indigo blue with several zeolitic matrices (LTA zeolite, mordenite, MFI zeolite). The manufacturing of the hybrid pigment is tested under varying oxidizing conditions, using Raman and ultraviolet–visible (UV-Vis) spectrometric techniques. Blending indigo with MFI is shown to yield the most stable composite in all of our artificial indigo pigments. In the absence of defects and substituted cations such as aluminum in the framework of the MFI zeolite matrix, we show that matching the pore size with the dimensions of the guest indigo molecule is the key factor. The evidence for the high color stability of indigo@MFI opens a new path for modeling the stability of indigo in various alumino-silicate substrates such as in the historical Maya Blue pigment.
Characterization of Automotive Paint Clear Coats by Ultraviolet Absorption Microspectrophotometry with Subsequent Chemometric Analysis
Authors: Liszewski Elisa A. , Lewis Simon W. , Siegel Jay A. , Goodpaster John V.
Published: October 2010

Clear coats have been a staple in automobile paints for almost thirty years and are of forensic interest when comparing transferred and native paints. However, the ultraviolet (UV) absorbers in these paint layers are not typically characterized using UV microspectrophotometry, nor are the results studied using multivariate statistical methods. In this study, measurements were carried out by UV microspectrophotometry on 71 samples from American and Australian automobiles, with subsequent chemometric analysis of the absorbance spectra. Sample preparation proved to be vital in obtaining accurate absorbance spectra and a method involving peeling the clear coat layer and not using a mounting medium was preferred. Agglomerative hierarchical clustering indicated three main groups of spectra, corresponding to spectra with one, two, and three maxima. Principal components analysis confirmed this clustering and the factor loadings indicated that a substantial proportion of the variance in the data set originated from specific spectral regions (230–265 nm, 275–285 nm, and 300–370 nm). The three classes were well differentiated using discriminant analysis, where the cross-validation accuracy was 91.6% and the external validation accuracy was 81.1%. However, results showed no correlation between the make, model, and year of the automobiles.
Self-Consistent Algorithm for Calibrating Spectrometers to Picometer Accuracy over the Entire Wavelength Range
Authors: Perret Edith , Balmer Tobias E. , Heuberger Manfred
Published: October 2010

Spectrometer calibration accuracies are of high importance for a wide range of applications. Typically, one calibrates the spectrometer with a calibration lamp, providing distinct and well-defined calibration lines. However, for small spectral ranges, where only two calibration lines are present, the calibration becomes inaccurate. We present a high-precision nonlinear wavelength calibration method, which is based on two or more reference lines from a calibration lamp. The additional key element introduced is a Fabry-Perot multilayer structure that yields multiple sharp transmission maxima of similar intensity over the full spectrometer range under broad-band illumination (e.g., white-light source). An iterative algorithm is put forward to obtain a self-consistent calibration of picometer precision over the full spectrometer range. In regions distant from calibration lines the accuracy is enhanced by at least a factor of two compared to conventional methods.
Distinct Frontoparietal Networks Set the Stage for Later Perceptual Identification Priming and Episodic Recognition Memory
Authors: Wimber Maria , Heinze Hans-Jochen , Richardson-Klavehn Alan
Published: October 2010

Recent imaging evidence suggests that a network of brain regions including the medial temporal lobe, ventrolateral prefrontal cortex, and dorsal posterior parietal cortex supports the successful encoding of long-term memories. Other areas, like the ventral posterior parietal and dorsolateral prefrontal cortices, have been associated with encoding failure rather than success. In line with the transfer-appropriate processing view, we hypothesized that distinct neural networks predict successful encoding depending on whether the later memory test draws primarily on perceptual or conceptual memory representations. Following an encoding phase, memory was assessed in a combined incidental perceptual identification and intentional recognition memory test. We found that during encoding, activation in ventral posterior parietal and dorsolateral prefrontal cortex predicted successful perceptual identification priming, whereas activation in ventrolateral prefrontal and dorsal posterior parietal cortex predicted successful recognition memory. Extending recent theories of attention to memory, the results suggest that ventral parietal regions support stimulus-driven attention to perceptual item features, forming memories accessed by later perceptual memory tests, whereas dorsal parietal regions support attention to meaningful item features, forming memories accessed by later conceptual memory tests.
Targeting NMNAT1 to Axons and Synapses Transforms Its Neuroprotective PotencyIn Vivo
Authors: Babetto Elisabetta , Beirowski Bogdan , Janeckova Lucie , Brown Rosalind , Gilley Jonathan , Thomson Derek , Ribchester Richard R. , Coleman Michael P.
Published: October 2010

Axon and synapse degeneration are common components of many neurodegenerative diseases, and their rescue is essential for effective neuroprotection. The chimeric Wallerian degeneration slow protein (WldS) protects axons dose dependently, but its mechanism is still elusive. We recently showed that WldSacts at a non-nuclear location and is present in axons. This and other recent reports support a model in which WldSprotects by extranuclear redistribution of its nuclear NMNAT1 portion. However, it remains unclear whether cytoplasmic NMNAT1 acts locally in axons and synapses or at a non-nuclear site within cell bodies. The potency of axon protection by non-nuclear NMNAT1 relative to WldSalso needs to be establishedin vivo. Because the N-terminal portion of WldS(N70) localized to axons, we hypothesized that it mediates the trafficking of the NMNAT1 portion. To test this, we substituted N70 with an axonal targeting peptide derived from amyloid precursor protein, and fused this to NMNAT1 with disrupted nuclear targeting. In transgenic mice, this transformed NMNAT1 from a molecule unable to inhibit Wallerian degeneration, even at high expression levels, into a protein more potent than WldS, able to preserve injured axons for several weeks at undetectable expression levels. Preventing NMNAT1 axonal delivery abolished its protective effect. Axonally targeted NMNAT1 localized to vesicular structures, colocalizing with extranuclear WldS, and was cotransported at least partially with mitochondria. We conclude that axonal targeting of NMNAT activity is both necessary and sufficient to delay Wallerian degeneration, and that promoting axonal and synaptic delivery greatly enhances the effectiveness.
Serotonin, But NotN-Methyltryptamines, Activates the Serotonin 2A Receptor Via a β-Arrestin2/Src/Akt Signaling ComplexIn Vivo
Authors: Schmid Cullen L. , Bohn Laura M.
Published: October 2010

Hallucinogens mediate many of their psychoactive effects by activating serotonin 2A receptors (5-HT2AR). Although serotonin is the cognate endogenous neurotransmitter and is not considered hallucinogenic, metabolites of serotonin also have high affinity at 5-HT2AR and can induce hallucinations in humans. Here we report that serotonin differs from the psychoactiveN-methyltryptamines by its ability to engage a β-arrestin2-mediated signaling cascade in the frontal cortex. Serotonin and 5-hydroxy-l-tryptophan (5-HTP) induce a head-twitch response in wild-type (WT) mice that is a behavioral proxy for 5-HT2AR activation. The response in β-arrestin2 knock-out (βarr2-KO) mice is greatly attenuated until the doses are elevated, at which point, βarr2-KO mice display a head-twitch response that can exceed that of WT mice. Direct administration ofN-methyltryptamines also produces a greater response in βarr2-KO mice. Moreover, the inhibition ofN-methyltransferase blocks 5-HTP-induced head twitches in βarr2-KO mice, indicating thatN-methyltryptamines, rather than serotonin, primarily mediate this response. Biochemical studies demonstrate that serotonin stimulates Akt phosphorylation in the frontal cortex and in primary cortical neurons through the activation of a β-arrestin2/phosphoinositide 3-kinase/Src/Akt cascade, whereasN-methyltryptamines do not. Furthermore, disruption of any of the components of this cascade prevents 5-HTP-induced, but notN-methyltryptamine-induced, head twitches. We propose that there is a bifurcation of 5-HT2AR signaling that is neurotransmitter and β-arrestin2 dependent. This demonstration of agonist-directed 5-HT2AR signalingin vivomay significantly impact drug discovery efforts for the treatment of disorders wherein hallucinations are part of the etiology, such as schizophrenia, or manifest as side effects of treatment, such as depression.
Control of Exocytosis by Synaptotagmins and Otoferlin in Auditory Hair Cells
Authors: Beurg Maryline , Michalski Nicolas , Safieddine Saaid , Bouleau Yohan , Schneggenburger Ralf , Chapman Edwin R. , Petit Christine , Dulon Didier
Published: October 2010

In pre-hearing mice, vesicle exocytosis at cochlear inner hair cell (IHC) ribbon synapses is triggered by spontaneous Ca2+spikes. At the onset of hearing, IHC exocytosis is then exclusively driven by graded potentials, and is characterized by higher Ca2+efficiency and improved synchronization of vesicular release. The molecular players involved in this transition are still unknown. Here we addressed the involvement of synaptotagmins and otoferlin as putative Ca2+sensors in IHC exocytosis during postnatal maturation of the cochlea. Using cell capacitance measurements, we showed that Ca2+-evoked exocytosis in mouse IHCs switches from an otoferlin-independent to an otoferlin-dependent mechanism at postnatal day 4. During this early exocytotic period, several synaptotagmins (Syts), including Syt1, Syt2 and Syt7, were detected in IHCs. The exocytotic response as well as the release of the readily releasable vesicle pool (RRP) was, however, unchanged in newborn mutant mice lacking Syt1, Syt2 or Syt7 (Syt1−/−,Syt2−/−andSyt7−/−mice). We only found a defect in RRP recovery inSyt1−/−mice which was apparent as a strongly reduced response to repetitive stimulations. In post-hearingSyt2−/−andSyt7−/−mutant mice, IHC synaptic exocytosis was unaffected. The transient expression of Syt1 and Syt2, which were no longer detected in IHCs after the onset of hearing, indicates that these two most common Ca2+-sensors in CNS synapses are not involved in mature IHCs. We suggest that otoferlin underlies highly efficient Ca2+-dependent membrane-membrane fusion, a process likely essential to increase the probability and synchrony of vesicle fusion events at the mature IHC ribbon synapse.
Hippocampal c-Jun-N-Terminal Kinases Serve as Negative Regulators of Associative Learning
Authors: Sherrin Tessi , Blank Thomas , Hippel Cathrin , Rayner Martin , Davis Roger J. , Todorovic Cedomir
Published: October 2010

In the adult mouse, signaling through c-Jun N-terminal kinases (JNKs) links exposure to acute stress to various physiological responses. Inflammatory cytokines, brain injury and ischemic insult, or exposure to psychological acute stressors induce activation of hippocampal JNKs. Here we report that exposure to acute stress caused activation of JNKs in the hippocampal CA1 and CA3 subfields, and impaired contextual fear conditioning. Conversely, intrahippocampal injection of JNKs inhibitors sp600125 (30 μm) ord-JNKI1 (8 μm) reduced activity of hippocampal JNKs and rescued stress-induced deficits in contextual fear. In addition, intrahippocampal administration of anisomycin (100 μg/μl), a potent JNKs activator, mimicked memory-impairing effects of stress on contextual fear. This anisomycin-induced amnesia was abolished after cotreatment with JNKs selective inhibitor sp600125 without affecting anisomycin's ability to effectively inhibit protein synthesis as measured by c-Fos immunoreactivity. We also demonstrated milder and transient activation of the JNKs pathway in the CA1 subfield of the hippocampus during contextual fear conditioning and an enhancement of contextual fear after pharmacological inhibition of JNKs under baseline conditions. Finally, using combined biochemical and transgenic approaches with mutant mice lacking different members of the JNK family (Jnk1, Jnk2, andJnk3), we provided evidence that JNK2 and JNK3 are critically involved in stress-induced deficit of contextual fear, while JNK1 mainly regulates baseline learning in this behavioral task. Together, these results support the possibility that hippocampal JNKs serve as a critical molecular regulator in the formation of contextual fear.
Functional Requirements for Reward-Modulated Spike-Timing-Dependent Plasticity
Authors: Frémaux Nicolas , Sprekeler Henning , Gerstner Wulfram
Published: October 2010

Recent experiments have shown that spike-timing-dependent plasticity is influenced by neuromodulation. We derive theoretical conditions for successful learning of reward-related behavior for a large class of learning rules where Hebbian synaptic plasticity is conditioned on a global modulatory factor signaling reward. We show that all learning rules in this class can be separated into a term that captures the covariance of neuronal firing and reward and a second term that presents the influence of unsupervised learning. The unsupervised term, which is, in general, detrimental for reward-based learning, can be suppressed if the neuromodulatory signal encodes the difference between the reward and the expected reward—but only if the expected reward is calculated for each task and stimulus separately. If several tasks are to be learned simultaneously, the nervous system needs an internal critic that is able to predict the expected reward for arbitrary stimuli. We show that, with a critic, reward-modulated spike-timing-dependent plasticity is capable of learning motor trajectories with a temporal resolution of tens of milliseconds. The relation to temporal difference learning, the relevance of block-based learning paradigms, and the limitations of learning with a critic are discussed.
Bulk Segregation Mapping of Mutations in Closely Related Strains of Mice
Authors: Xia Yu , Won Sungyong , Du Xin , Lin Pei , Ross Charles , Vine Diantha La , Wiltshire Sean , Leiva Gabriel , Vidal Silvia M , Whittle Belinda , Goodnow Christopher C , Koziol James , Moresco Eva Marie Y , Beutler Bruce
Published: October 2010

Phenovariance may be obscured when genetic mapping is performed using highly divergent strains, and closely similar strains are preferred if adequate marker density can be established. We sequenced the C57BL/10J mouse genome using the Applied Biosystems SOLiD platform and here describe a genome-wide panel of informative markers that permits the mapping of mutations induced on the closely related C57BL/6J background by outcrossing to C57BL/10J, and backcrossing or intercrossing. The panel consists of 127 single nucleotide polymorphisms validated by capillary sequencing: 124 spaced at ∼20-Mb intervals across the 19 autosomes, and three markers on the X chromosome. We determined the genetic relationship between four C57BL-derived substrains and used the panel to map two N-ethyl-N-nitrosourea (ENU)-induced mutations responsible for visible phenotypes in C57BL/6J mice through bulk segregation analysis. Capillary sequencing, with computation of relative chromatogram peak heights, was used to determine the proportion of alleles from each strain at each marker.
Functional Specialization of Sensory Cilia by an RFX Transcription Factor Isoform
Authors: Wang Juan , Schwartz Hillel T , Barr Maureen M
Published: October 2010

In animals, RFX transcription factors govern ciliogenesis by binding to an X-box motif in the promoters of ciliogenic genes. In Caenorhabditis elegans, the sole RFX transcription factor (TF) daf-19 null mutant lacks all sensory cilia, fails to express many ciliogenic genes, and is defective in many sensory behaviors, including male mating. The daf-19c isoform is expressed in all ciliated sensory neurons and is necessary and sufficient for activating X-box containing ciliogenesis genes. Here, we describe the daf-19(n4132) mutant that is defective in expression of the sensory polycystic kidney disease (PKD) gene battery and male mating behavior, without affecting expression of ciliogenic genes or ciliogenesis. daf-19(n4132) disrupts expression of a new isoform, daf-19m (for function in male mating). daf-19m is expressed in male-specific PKD and core IL2 neurons via internal promoters and remote enhancer elements located in introns of the daf-19 genomic locus. daf-19m genetically programs the sensory functions of a subset of ciliated neurons, independent of daf-19c. In the male-specific HOB neuron, DAF-19M acts downstream of the zinc finger TF EGL-46, indicating that a TF cascade controls the PKD gene battery in this cell-type specific context. We conclude that the RFX TF DAF-19 regulates ciliogenesis via X-box containing ciliogenic genes and controls ciliary specialization by regulating non-X-box containing sensory genes. This study reveals a more extensive role for RFX TFs in generating fully functional cilia.
The Elusive Minimum Viable Population Size for White Sturgeon
Authors: Jager Henriette I. , Lepla Ken B. , Van Winkle Webb , James Brad W. , McAdam Steven O.
Published: October 2010

Damming of large rivers in the U.S. Pacific Northwest and Canada has divided the historical population of white sturgeonAcipenser transmontanusinto more than 36 fragmented populations, few of which are thriving. We now face the challenge of managing these populations to avoid extirpation. Two goals of this study were to identify extinction thresholds related to small size and inadequate habitat for this species. The minimum viable population size (MVP) is the threshold size above which populations support recruitment and grow and below which populations fail to support recruitment and decline. We estimated a single, cross‐population MVP using data from multiple populations and quantile regression, which removed the effects of factors other than population size. Only two populations (those in the Bonneville and Dalles reservoirs on the Columbia River), both with significant increasing trends, were larger than our MVP estimate. We detected significant decreasing trends in two populations—those below Bonneville Dam and in the Kootenai River. To discover how site‐specific differences in river habitat influence MVP, we used a population viability analysis (PVA) model that incorporated Allee mechanisms. The PVA model identified a river segment length below which extinction was certain regardless of initial population size. Above this threshold, simulated populations in river segments that were longer or that provided more frequent recruitment opportunities were able to persist with smaller initial sizes. Two priorities emerged for white sturgeon: monitoring age structure and understanding the circumstances preventing recruitment to age 1. Our results ultimately guided us toward thresholds in rearing habitat and age structure that promise to develop into more useful conservation tools than MVP for this and similar long‐lived species.
Long‐Term Trends in Habitat Use of Offshore Demersal Fishes in Western Lake Huron Suggest Large‐Scale Ecosystem Change
Authors: Riley Stephen C. , Adams Jean V.
Published: October 2010

We estimated mean depths of capture for offshore demersal fish species, grouped into three habitat‐based guilds (shallow benthic, pelagic, and deep benthic), using fall bottom trawl data (27–73 m) in the western main basin of Lake Huron from 1976 to 2007. The mean depth of capture of the shallow and deep benthic guilds initially exhibited a trend toward capture in shallower water, switched to a trend toward capture in deeper water in 1991, and changed back to a trend toward capture in shallower water in 2001–2002. Species in the pelagic guild showed a similar pattern, but the initial change point occurred in 1981 for this guild. Individual species in these guilds showed variable patterns of depth distribution, but a feature common to all guilds and all pelagic and deep benthic species was a change to a trend toward capturing fish in shallower water that occurred nearly simultaneously (1999–2002). These common trends suggest that large‐scale factors are affecting the habitat use of offshore demersal fish species in Lake Huron. The depth distributions of the three guilds have converged in recent years, indicating that the locations of suitable habitat for offshore demersal fishes may be changing. Our results indicate that the benthic ecology of the western main basin of Lake Huron is undergoing profound changes across a large spatial scale that are affecting the habitat use of offshore demersal fishes. We suggest that these changes are related to recent invasions of exotic species.
Intra‐ and Intersystem Variation in Largemouth Bass Recruitment: Reproduction, Prey Availability, and the Timing of Year‐Class Establishment
Authors: Parkos Joseph J. , Wahl D. H.
Published: October 2010

Incorporating potentially important events during the first year of life across multiple environmental conditions is needed to generalize models of fish recruitment. Using previous conceptual models as a framework, we quantified sources of intra‐ and intersystem variation in recruitment of largemouth bass Micropterus salmoides. We measured age‐0 abundances, first‐year growth, and potentially important environmental variables across 12 populations and 5–7 year‐classes. Interpopulation differences in average recruitment to age 1 were set by variation in number of age‐0 fish surviving to the fall. Survival to fall was in turn positively related to density of juvenile bluegills Lepomis macrochirus. First‐year growth was positively related to turbidity and adult largemouth bass abundance. For individual lakes, variables explaining a significant amount of intrapopulation variation in recruitment strength were factors associated with either production of age‐0 fish from the parental care stage (peak density of age‐0 largemouth bass) or prey fish abundance (densities of larval and juvenile bluegills). Abundance of larval bluegills was higher in systems where largemouth bass recruitment to age 1 was not related to bluegill abundance than in lakes where recruitment strength was sensitive to annual fluctuations in prey fish abundance. The relationship between output from the parental care stage and recruitment strength suggests that largemouth bass management should focus on actions designed to influence nest success. Where recruitment is also limited by prey fish availability, management actions can also be directed towards community attributes that influence the growth and production of important prey species.
Contrasting Ecology Shapes Juvenile Lake‐Type and Riverine Sockeye Salmon
Authors: Pavey Scott A. , Nielsen Jennifer L. , MacKas Renae H. , Hamon Troy R. , Breden Felix
Published: October 2010

Here we compare the body shape of juvenile (age‐0) sockeye salmon Oncorhynchus nerka that rear in lakes (lake type) with that of those that rear in rivers (riverine) and relate rearing habitat to morphology and ecology. The two habitats present different swimming challenges with respect to water flow, foraging strategy, habitat complexity, and predation level. We present morphological data from three riverine and three lake‐type populations in southwest Alaska. Using multivariate analyses conducted via geometric morphometrics, we determine population‐ and habitat‐specific body shape. As predicted, riverine sockeye salmon have a more robust body shape, whereas lake‐type sockeye salmon have a more streamlined body shape. In particular, we found differences in caudal peduncle depth (riverine deeper), eye size (riverine larger), and overall body depth (riverine deeper). One lake‐type population did not follow the predicted pattern, exhibiting an overall exaggerated riverine body shape. Differences between the habitats in terms of predation, complexity, and foraging ecology are probably drivers of these differences. Allometry differed between life history types, suggesting that there are habitat‐specific developmental differences.
Feasibility of Surgically Implanting Acoustic Tags into Pacific Herring
Authors: Seitz Andrew C. , Norcross Brenda L. , Payne John C. , Kagley Anna N. , Meloy Buck , Gregg Jacob L. , Hershberger Paul K.
Published: October 2010

Internally implanted acoustic tags represent a potentially valuable approach to assessing the seasonal migration and distribution patterns of Pacific herring Clupea palasii. We examined the feasibility of implanting two sizes of dummy acoustic tags (9 mm in diameter × 21 mm long, 1.6 g; and 7 mm in diameter × 18 mm long, 0.7 g) in Pacific herring that had been held in captivity for nearly a year and that ranged from 165 to 215 mm in fork length (FL) and from 41.6 to 142.6 g. Relatively low mortality (4%) and tag shedding (4%), as well as growth similar to that observed in control fish after 135 d, indicate that, with proper handling, Pacific herring are amenable to surgical implantation of acoustic tags.
Detailed Examination of Ichthyoplankton Seasonality from a High‐Resolution Time Series in the Northern Gulf of Mexico during 2004–2006
Authors: Hernandez Frank J. , Powers Sean P. , Graham William M.
Published: October 2010

Ichthyoplankton samples collected during monthly cruises (October 2004–October 2006) off the coast of Alabama were used to characterize taxon‐specific larval fish seasonality for taxa representing 58 different families of fishes. Mean concentrations for total fish larvae peaked in the summer (August), while taxonomic diversity was generally highest during the spring and summer months (March–October). Taxonomic richness was generally highest during the late summer and early fall. Dominant taxonomic groups included unidentified anchovies (Engraulidae), sand seatrout Cynoscion arenarius, Atlantic bumper Chloroscombrus chrysurus, Atlantic croaker Micropogonias undulatus, Gulf menhaden Brevoortia patronus, tonguefishes Symphurus spp., unidentified gobies (Gobiidae), drums (Sciaenidae), and cusk‐eels (Ophidiidae). Our characterization of larval fish seasonality for coastal Alabama largely agreed with results from a synthesis (published in 1988) of larval fish seasonality in the northern Gulf of Mexico. For most of the dominant taxa examined, our collections indicated a contracted seasonal distribution (i.e., larvae were collected during months that were central to the previously reported seasonality and less so at the endpoints of their temporal occurrence). However, most of the sciaenids examined had the opposite trend, suggesting expanded seasonal occurrences in the plankton. This first‐order comparison of the timing of taxon‐specific larval fish supply in the northern Gulf of Mexico provides a framework for examining climate‐related temporal shifts in adult fish spawning patterns and larval fish seasonality.
Administração do tempo nas atividades de enfermagem de uma UTI
Authors: Alencar Karleny dos Santos , Diniz Rita de Cássia Moura , Lima Flavia Regina Furtado
Published: October 2010

O trabalho investigou como enfermeiras assistenciais de uma Unidade de Terapia Intensiva (UTI) empregam seu tempo durante a execução de suas atividades e quais estratégias utilizam para realizá-las. Trata-se de um estudo exploratório e descritivo, realizado numa instituição pública na cidade de Fortaleza/CE. A pesquisa ocorreu de fevereiro a abril de 2004, havendo sido utilizados como instrumentos uma entrevista e um check list. Os dados foram apresentados em figuras. As falas foram lidas e interpretadas, tendo como referencial teórico literaturas sobre administração do tempo. Percebemos que as enfermeiras não aproveitam adequadamente seu tempo, relatam estar sempre sobrecarregadas e realizando tarefas burocráticas que não lhes competem. Delegam tarefas aos auxiliares, para desenvolverem suas atividades durante a jornada de trabalho. Entretanto, faz-se necessário um redimensionamento de pessoal para melhoria da assistência de Enfermagem.
Auditoria do método de assistência de enfermagem
Authors: Faraco Michel Maximiano , Albuquerque Gelson Luiz de
Published: October 2010

Este estudo descreve o desenvolvimento de um processo de auditoria do Método de Assistência de Enfermagem em uma unidade de internação de um Hospital Universitário. Identificados os padrões, elaborou-se o instrumento, sob a forma de indicadores, no qual foram examinados, aleatoriamente, cinco prontuários com exame do usuário "in loco". Os dados foram mensurados e classificados numa quanti-qualificação da assistência de Enfermagem. Os resultados encontrados indicam a necessidade de revisão dos Padrões do Método de Assistência de Enfermagem e da retomada imediata do programa de auditoria da assistência de Enfermagem.
As organizações de saúde na perspectiva da complexidade dos sistemas de cuidado
Authors: Erdmann Alacoque Lorenzini , Mello Ana Lúcia Schaefer Ferreira de , Meirelles Betina Hörner Schlindwein , Marino Selma Regina de Andrade
Published: October 2010

A construção de novas práticas de cuidado pressupõe um novo olhar para as organizações de saúde. O objetivo é interpretar o tema da complexidade na saúde e na Enfermagem na perspectiva dos sistemas de cuidado, buscando um repensar das práticas de cuidado no contexto das organizações de saúde. O pensamento complexo traz consigo uma nova maneira de conceber a ação e a condição humana sob diferentes perspectivas. Surge como possibilidade para visualizar o sistema de cuidado como sistema complexo nas suas estruturas e propriedades, nos movimentos de inter-retroações nos espaços organizacionais e nos seus processos auto-organizadores. Espera-se uma ação transformadora das organizações de saúde que considere as ambigüidades, as incertezas e a dinâmica social contemporânea para um viver mais saudável.
Tendências modernas da gerência do trabalho da enfermagem: o caso das cooperativas
Authors: Guimarães Raphael Mendonça , Muzi Camila Drumond , Mauro Maria Yvone Chaves
Published: October 2010

O presente artigo introduz a problemática da gerência do trabalho em Enfermagem a partir de uma perspectiva teórico conceitual, levantando algumas implicações para a gerência das organizações, bem como seu impacto nas relações de trabalho e, conseqüentemente, para a saúde do trabalhador. Os principais resultados sobre formas e modalidades de cooperativas trazem a reflexão de que a proposta de mudanças positivas na categoria seguem na mão oposta ao progresso. Condições indignas de trabalho, assistência de pouca qualidade e remuneração baixa constituem principais fatores negativos deste processo de trabalho. Urge, portanto, retomar a discussão do que se espera da Enfermagem para os próximos tempos.
Inclusão da competência interpessoal na formação do enfermeiro como gestor
Authors: Munari Denize Bouttelet , Bezerra Ana Lucia Queiroz
Published: October 2010

Este artigo se propõe a apresentar reflexões sobre a necessidade de incluir o desenvolvimento da competência interpessoal no processo de formação do enfermeiro gestor. Destaca as tendências da gestão contemporânea e a importância da construção de relacionamentos interpessoais como base para as ações do gestor. A inclusão da competência interpessoal, nesse sentido, pode influenciar na transformação da prática gerencial do enfermeiro e na formação de um líder que consiga avaliar e dimensionar os problemas de modo global e exercer o seu papel com segurança e transparência.
Liderança e enfermagem: elementos para reflexão
Authors: Oliveira Alcinéa Cristina Ferreira de , Paz Aneth Rolin de Araújo da , Telles Eleny Alves de Britto , Leite Joséte Luzia , Stipp Marluci Andrade Conceição
Published: October 2010

Este trabalho objetiva apresentar uma reflexão sobre a temática liderança na enfermagem tomando por base uma situação concreta vivenciada por um grupo de enfermeiras do Programa de Pós-graduação do Curso de Mestrado e Doutorado da Escola de Enfermagem Anna Nery, da Universidade Federal do Rio de Janeiro - EEAN/UFRJ. As discussões emergiram de um seminário sobre a temática proposta, e pontuaram outras interrogações que articulam a liderança e o poder com o processo de formação profissional do enfermeiro, contextualizando com o mundo do trabalho de forma reflexiva, uma vez que todas as enfermeiras exercem papéis de liderança em suas práticas profissionais.