54 research outputs found
A New Strategy for Smoking Cessation: Characterization of a Bacterial Enzyme for the Degradation of Nicotine
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
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).
<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).
<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
<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
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
<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).
<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).
<p>Red bar refers to negative target and black bar refers to positive target.</p
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