54 research outputs found

    A New Strategy for Smoking Cessation: Characterization of a Bacterial Enzyme for the Degradation of Nicotine

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    Smoking is the leading cause of preventable diseases; thus, effective smoking cessation aids are crucial for reducing the prevalence of cigarette smoking and smoking-related illnesses. In our current campaign we offer a nicotine-degrading enzyme from <i>Pseudomonas putida</i>, NicA2, a flavin-containing protein. To explore its potential, a kinetic evaluation of the enzyme was conducted, which included determination of <i>K</i><sub>m</sub>, <i>k</i><sub>cat</sub>, buffer/serum half-life, and thermostability. Additionally, the catabolism profile of NicA2 was elucidated to assess the potential toxicity of the nicotine-derived products. In characterizing the enzyme, a favorable biochemical profile of the enzyme was discovered, making NicA2 a prospective therapeutic candidate. This approach provides a new avenue for the field of nicotine addiction therapy

    Tunable Streaming Current in a pH-Regulated Nanochannel by a Field Effect Transistor

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    Many experimental results demonstrated that ion transport phenomena in nanofluidic devices are strongly dependent on the surface charge property of the nanochannel. In this study, active control of the surface charge property and the streaming current, generated by a pressure-driven flow, in a pH-regulated nanochannel using a field effect transistor (FET) are analyzed for the first time. Analytical expressions for the surface charge property and the streaming current/conductance have been derived taking into account multiple ionic species, surface chemistry reactions, and the Stern layer effect. The model is validated by the experimental data of the streaming conductance in the silica nanochannel available in the literature. Results show that the pH-dependent streaming conductance of the gated silica nanochannel is consistent with its modulated zeta potential; however, the salt concentration-dependent streaming conductance might be different from the zeta potential behavior, depending on the solution pH and the gate potential imposed. The performance of the field effect modulation of the zeta potential and the streaming conductance is significant for lower solution pH and salt concentration. The results gathered are informative for the design of the next-generation nanofluidics-based power generation apparatus

    The average ERPs at Cz and FCz for congruent prime and incongruent prime conditions in Stroop effect (SOA = 800ms).

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    <p>Red line represents incongruent prime condition and black line represents congruent prime condition.</p

    The average ERPs at Cz and CPz for CP (congruent—positive), CN (congruent—negative), IP (incongruent—positive) and IN (incongruent—negative) conditions in priming effect (SOA = 800ms).

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    <p>Red line refers to positive target after congruent prime condition; red dashed line refers to negative target after congruent prime condition; black line refers to positive target after incongruent prime condition and black dashed line refers to negative target after incongruent prime condition.</p

    Different Stages, Different Signals: The Modulating Effect of Cognitive Conflict on Subsequent Processing

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    <div><p>The present study used event-related potentials (ERPs) to investigate the function of signals induced by cognitive conflict during the detection stage and the resolution stage of perceptual processing. The study used a combination of the Stroop task and an affective priming task to examine the conflict priming effect when the stimulus onset asynchrony (SOA) was 200 ms or 800 ms. Behavioral results showed that the RTs were shorter for positive targets following congruent primes relative to incongruent primes, and for negative targets following incongruent primes relative to congruent primes when the SOA was 200 ms. ERP results showed that the N2 amplitudes (200–300 ms) for incongruent stimuli were significantly larger than for congruent stimuli in the Stroop task, which indicated a significant conflict effect. Moreover, the N400 amplitudes (500–700 ms) for positive targets after congruent primes were significantly lower than those after incongruent primes when the SOA was 200 ms, which showed a significant negative priming effect. While the SOA was 800 ms, behavioral results showed that the RTs were shorter for positive targets following incongruent primes relative to congruent primes. ERP results showed that the N2 amplitudes (200–300 ms) for incongruent stimuli were significantly larger than for congruent stimuli in the Stroop task, which indicated a significant conflict effect. The N400 amplitudes (1100–1300 ms) for the negative targets after congruent primes were significantly lower than those after incongruent primes when the SOA was 800 ms, which showed a significant positive priming effect. The results demonstrated that the functions of signals induced by cognitive conflict were reversed in two different cognitive processing stages.</p></div

    Probing BoNT/A Protease Exosites: Implications for Inhibitor Design and Light Chain Longevity

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    Botulinum neurotoxin serotype A (BoNT/A) is one of the most lethal toxins known. Its extreme toxicity is due to its light chain (LC), a zinc protease that cleaves SNAP-25, a synaptosome-associated protein, leading to the inhibition of neuronal activity. Studies on BoNT/A LC have revealed that two regions, termed exosites, can play an important role in BoNT catalytic activity. A clear understanding of how these exosites influence neurotoxin catalytic activity would provide a critical framework for deciphering the mechanism of SNAP-25 cleavage and the design of inhibitors. Herein, based on the crystallographic structure of BoNT/A LC complexed with its substrate, we designed an α-exosite binding probe. Experiments with this unique probe demonstrated that α-exosite binding enhanced both catalytic activity and stability of the LC. These data help delineate why α-exosite binding is needed for SNAP-25 cleavage and also provide new insights into the extended lifetime observed for BoNT/A LC <i>in vivo</i>

    The results of the validity test

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    <p>*: p < 0.05,</p><p>**p < 0.01</p><p>a: because of the missing data, the samples in this table are different from the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115948#pone.0115948.t001" target="_blank">Table 1</a></p><p>The results of the validity test</p

    Mean RTs as a function of Prime Congruence and Target Valence (SOA = 800 ms).

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    <p>Red bar refers to negative target and black bar refers to positive target.</p

    Mean RTs as a function of Prime Congruence and Target Valence (SOA = 200 ms).

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    <p>Red bar refers to negative target and black bar refers to positive target.</p

    Demographics of the 4 samples.

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    <p>Demographics of the 4 samples.</p
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