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https://www.readbyqxmd.com/read/28441389/the-basis-of-sharp-spike-onset-in-standard-biophysical-models
#1
Maria Telenczuk, Bertrand Fontaine, Romain Brette
In most vertebrate neurons, spikes initiate in the axonal initial segment (AIS). When recorded in the soma, they have a surprisingly sharp onset, as if sodium (Na) channels opened abruptly. The main view stipulates that spikes initiate in a conventional manner at the distal end of the AIS, then progressively sharpen as they backpropagate to the soma. We examined the biophysical models used to substantiate this view, and we found that spikes do not initiate through a local axonal current loop that propagates along the axon, but through a global current loop encompassing the AIS and soma, which forms an electrical dipole...
2017: PloS One
https://www.readbyqxmd.com/read/28440688/simultaneous-identification-of-campylobacter-jejuni-campylobacter-coli-and-campylobacter-lari-with-smartcycler-based-multiplex-quantitative-polymerase-chain-reaction
#2
Kun C Liu, Karen C Jinneman, Jason Neal-McKinney, Wen-Hsin Wu, Daniel H Rice
BACKGROUND: Consumption of Campylobacter contaminated food or water is a leading cause of human acute gastroenteritis. Campylobacter jejuni, Campylobacter coli, and Campylobacter lari account for over 95% of total Campylobacter infections. A multiplex quantitative polymerase chain reaction (qPCR) for simultaneous identification of C. jejuni, C. coli, and C. lari was developed for use with the SmartCycler II system. MATERIALS AND METHODS: We evaluated and combined previously described primers and probes for Campylobacter detection, designed a new internal amplification control, and optimized the multiplex qPCR for the detection of C...
April 25, 2017: Foodborne Pathogens and Disease
https://www.readbyqxmd.com/read/28440221/nptx2-and-cognitive-dysfunction-in-alzheimer-s-disease
#3
Mei-Fang Xiao, Desheng Xu, Michael T Craig, Kenneth A Pelkey, Chun-Che Chien, Yang Shi, Juhong Zhang, Susan Resnick, Olga Pletnikova, David Salmon, James Brewer, Steven Edland, Jerzy Wegiel, Benjamin Tycko, Alena Savonenko, Roger H Reeves, Juan C Troncoso, Chris J McBain, Douglas Galasko, Paul F Worley
Memory loss in Alzheimer's disease (AD) is attributed to pervasive weakening and loss of synapses. Here, we present findings supporting a special role for excitatory synapses connecting pyramidal neurons of the hippocampus and cortex with fast-spiking parvalbumin (PV) interneurons that control network excitability and rhythmicity. Excitatory synapses on PV interneurons are dependent on the AMPA receptor subunit GluA4, which is regulated by presynaptic expression of the synaptogenic immediate early gene NPTX2 by pyramidal neurons...
March 23, 2017: ELife
https://www.readbyqxmd.com/read/28439779/searching-for-an-internal-representation-of-stimulus-kinematics-in-the-response-of-ventral-paraflocculus-purkinje-cells
#4
Pablo M Blazquez, GyuTae Kim, Tatyana A Yakusheva
Motor control theories propose that the central nervous system builds internal representations of the motion of both our body and external objects. These representations, called forward models, are essential for accurate motor control. For instance, to produce a precise reaching movement to catch a flying ball, the central nervous system must build predictions of the current and future states of both the arm and the ball. Accumulating evidence suggests that the cerebellar cortex contains a forward model of an individual's body movement...
April 24, 2017: Cerebellum
https://www.readbyqxmd.com/read/28438969/intracellular-in-vivo-dynamics-of-thalamocortical-synapses-in-visual-cortex
#5
Madineh Sedigh-Sarvestani, Leif Vigeland, Ivan Fernandez-Lamo, Morgan Taylor, Larry A Palmer, Diego Contreras
Seminal studies of the thalamocortical (TC) circuit in the visual system of the cat have been central to our understanding of sensory encoding. However, TC synaptic properties remain poorly understood. We used paired recordings, in the lateral geniculate nucleus (LGN) and primary visual cortex (V1), to provide the first in vivo characterization of sensory-driven TC potentials in V1. The amplitudes of EPSPs we characterized were smaller than those previously reported in vitro. Consistent with prior findings, connected LGN-V1 pairs were only found when their receptive fields (RFs) overlapped, and the probability of connection increased steeply with degree of RF overlap and response similarity...
April 24, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28438630/identification-of-anti-viral-activity-of-the-cardenolides-na-k-atpase-inhibitors-against-porcine-transmissible-gastroenteritis-virus
#6
Cheng-Wei Yang, Hsin-Yu Chang, Hsing-Yu Hsu, Yue-Zhi Lee, Hsun-Shuo Chang, Ih-Sheng Chen, Shiow-Ju Lee
A series of naturally occurring cardenolides that exhibit potent anti-transmissible gastroenteritis virus (TGEV) activity in swine testicular (ST) cells has been identified. In an immunofluorescence assay, these cardenolides were found to diminish the expressions of TGEV nucleocapsid and spike protein, which was used as an indication for viral replication; block TGEV infection induced apoptosis and cytopathic effects; and impart the same trend of inhibitory activity against Na(+)/K(+)-ATPase as for anti-TGEV activity...
April 21, 2017: Toxicology and Applied Pharmacology
https://www.readbyqxmd.com/read/28438022/improvements-in-nanoparticle-tracking-analysis-to-measure-particle-aggregation-and-mass-distribution-a-case-study-on-engineered-nanomaterial-stability-in-incineration-landfill-leachates
#7
Kamyar Mehrabi, Bernd Nowack, Yadira Arroyo Rojas Dasilva, Denise M Mitrano
Numerous nanometrology techniques have been developed in recent years to determine the size, concentration and a number of other characteristics of engineered nanomaterials (ENM) in environmental matrices. Among the many available techniques, Nanoparticle Tracking Analysis (NTA) can measure individual particles to create a size distribution and measure the particle number. Therefore, we explore the possibility to use these data to calculate the particle mass distribution. Additionally, we further developed the NTA methodology to explore its suitability for analysis of ENM in complex matrices by measuring ENM agglomeration and sedimentation in municipal solid waste incineration landfill leachates over time...
April 24, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28437771/solvent-bar-micro-extraction-sbme-based-determination-of-pahs-in-seawater-samples
#8
José A López-López, Esther Ogalla-Chozas, Pablo A Lara-Martín, Marina G Pintado-Herrera
Measuring the impact of PAHs in seawater samples is often difficult due to the low concentrations in which they appear and the complexity of the sample matrix. Traditional methods for sample preparation such as liquid-liquid extraction and solid phase extraction require the use of excessive amounts of solvents and reagents, and sample handling. In this work, hollow fiber liquid phase micro-extraction (HFLPME), in the configuration of solvent bar micro-extraction (SBME), was proposed as an environmentally friendly and more effective tool, for the extraction of the 16 priority PAHs from seawater samples...
April 21, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28437453/three-dominant-awnless-genes-in-common-wheat-fine-mapping-interaction-and-contribution-to-diversity-in-awn-shape-and-length
#9
Motohiro Yoshioka, Julio C M Iehisa, Ryoko Ohno, Tatsuro Kimura, Hiroyuki Enoki, Satoru Nishimura, Shuhei Nasuda, Shigeo Takumi
The awn is a long needle-like structure formed at the tip of the lemma in the florets of some grass species. It plays a role in seed dispersal and protection against animals, and can contribute to the photosynthetic activity of spikes. Three main dominant inhibitors of awn development (Hd, B1 and B2) are known in hexaploid wheat, but the causal genes have not been cloned yet and a genetic association with awn length diversity has been found only for the B1 allele. To analyze the prevalence of these three awning inhibitors, we attempted to predict the genotypes of 189 hexaploid wheat varieties collected worldwide using markers tightly linked to these loci...
2017: PloS One
https://www.readbyqxmd.com/read/28437436/intrinsically-generated-fluctuating-activity-in-excitatory-inhibitory-networks
#10
Francesca Mastrogiuseppe, Srdjan Ostojic
Recurrent networks of non-linear units display a variety of dynamical regimes depending on the structure of their synaptic connectivity. A particularly remarkable phenomenon is the appearance of strongly fluctuating, chaotic activity in networks of deterministic, but randomly connected rate units. How this type of intrinsically generated fluctuations appears in more realistic networks of spiking neurons has been a long standing question. To ease the comparison between rate and spiking networks, recent works investigated the dynamical regimes of randomly-connected rate networks with segregated excitatory and inhibitory populations, and firing rates constrained to be positive...
April 24, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28436835/neural-spike-train-synchronisation-indices-definitions-interpretations-and-applications
#11
D M Halliday, J R Rosenberg
A comparison of previously defined spike train syncrhonization indices is undertaken within a stochastic point process framework. The second order cumulant density (covariance density) is shown to be common to all the indices. Simulation studies were used to investigate the sampling variability of a single index based on the second order cumulant. The simulations used a paired motoneurone model and a paired regular spiking cortical neurone model. The sampling variability of spike trains generated under identical conditions from the paired motoneurone model varied from 50% { 160% of the estimated value...
April 24, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28436098/lecrk-v-an-l-type-lectin-receptor-kinase-in-haynaldia-villosa-plays-positive-role-in-resistance-to-wheat-powdery-mildew
#12
Zongkuan Wang, Jiangyue Cheng, Anqi Fan, Jia Zhao, Zhongyu Yu, Yingbo Li, Heng Zhang, Jin Xiao, Faheem Mohammad, Haiyan Wang, Aizhong Cao, Liping Xing, Xiue Wang
Plant sense potential microbial pathogen by using pattern recognition receptors (PRRs) to recognize pathogen associated molecular patterns (PAMPs). The Lectin receptor like kinase genes (LecRKs) are involved in various cellular processes mediated by signal transduction pathways. In the present study, an L-type lectin receptor kinase gene LecRK-V was cloned from Haynaldia villosa, a diploid wheat relative which is highly resistant to powdery mildew. The expression of LecRK-V was rapidly up-regulated by Bgt inoculation and chitin treatment...
April 24, 2017: Plant Biotechnology Journal
https://www.readbyqxmd.com/read/28436051/a-novel-mass-spectrometry-based-method-for-simultaneous-determination-of-asymmetric-and-symmetric-dimethylarginine-l-arginine-and-l-citrulline-optimized-for-lc-ms-tof-and-lc-ms-ms
#13
Jerzy Wiśniewski, Mariusz G Fleszar, Joanna Piechowicz, Małgorzata Krzystek-Korpacka, Angelika Chachaj, Andrzej Szuba, Katarzyna Lorenc-Kukula, Leszek Masłowski, Wojciech Witkiewicz, Andrzej Gamian
Nitric oxide (NO) is a regulatory molecule involved in many biological processes. NO is produced by nitric oxide synthase by conversion of L-arginine to L-citrulline. L-arginine methylated derivatives, asymmetric and symmetric dimethylarginines (ADMA and SDMA), regulate L-arginine availability and the activity of nitric oxide synthase. As such, they have been frequently investigated as potential biomarkers in pathologies associated with dysfunctions in NO synthesis. Here, we present a new multistep analytical methodology based on liquid chromatography combined with mass spectrometry for the accurate identification of L-arginine, L-citrulline, ADMA, and SDMA...
April 24, 2017: Biomedical Chromatography: BMC
https://www.readbyqxmd.com/read/28434916/the-tetrameric-plant-lectin-banlec-neutralizes-hiv-through-bidentate-binding-to-specific-viral-glycans
#14
Jonathan T S Hopper, Stephen Ambrose, Oliver C Grant, Stefanie A Krumm, Timothy M Allison, Matteo T Degiacomi, Mark D Tully, Laura K Pritchard, Gabriel Ozorowski, Andrew B Ward, Max Crispin, Katie J Doores, Robert J Woods, Justin L P Benesch, Carol V Robinson, Weston B Struwe
Select lectins have powerful anti-viral properties that effectively neutralize HIV-1 by targeting the dense glycan shield on the virus. Here, we reveal the mechanism by which one of the most potent lectins, BanLec, achieves its inhibition. We identify that BanLec recognizes a subset of high-mannose glycans via bidentate interactions spanning the two binding sites present on each BanLec monomer that were previously considered separate carbohydrate recognition domains. We show that both sites are required for high-affinity glycan binding and virus neutralization...
April 17, 2017: Structure
https://www.readbyqxmd.com/read/28434713/detection-of-trace-fluoride-in-serum-and-urine-by-online-membrane-based-distillation-coupled-with-ion-chromatography
#15
Chaoyan Lou, Dandan Guo, Nani Wang, Shuchao Wu, Peimin Zhang, Yan Zhu
An online membrane-based distillation (MBD) coupled with ion chromatography (IC) method was proposed for automatic detection of trace fluoride (F(-)) in serum and urine samples. The system consisted of a sample vessel, a lab-made membrane module and an ion chromatograph. Hydrophobic polytetrafluoroethylene (PTFE) hollow fiber membrane was used in MBD which was directly performed in serum and urine samples to eliminate the matrix interferences and enrich fluoride, while enabling automation. The determination of fluoride in biological samples was carried out by IC with suppressed conductometric detection...
April 14, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28434711/validation-of-an-ultra-high-performance-liquid-chromatography-tandem-mass-spectrometry-method-to-quantify-illicit-drug-and-pharmaceutical-residues-in-wastewater-using-accuracy-profile-approach
#16
Cécile Hubert, Martin Roosen, Yves Levi, Sara Karolak
The analysis of biomarkers in wastewater has become a common approach to assess community behavior. This method is an interesting way to estimate illicit drug consumption in a given population: by using a back calculation method, it is therefore possible to quantify the amount of a specific drug used in a community and to assess the consumption variation at different times and locations. Such a method needs reliable analytical data since the determination of a concentration in the ngL(-1) range in a complex matrix is difficult and not easily reproducible...
April 15, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28434238/the-characteristics-and-long-term-course-of-epilepsy-in-lipoid-proteinosis-a-spectrum-from-mild-to-severe-seizures-in-relation-to-ecm1-mutations
#17
Emel Oguz Akarsu, Firdevs Dinçsoy Bir, Can Baykal, Volkan Taşdemir, Bülent Kara, Nerses Bebek, Candan Gürses, Oya Uyguner, Betül Baykan
Lipoid proteinosis (LP) is a rare autosomal recessive disease characterized by deposition of hyaline material in skin and mucosae. Epilepsy, as an extracutaneous manifestation associated with typical mesial temporal calcifications, has already been identified, but its characteristics and long-term prognosis have not been thoroughly investigated. We included 7 consecutive patients with LP with typical intracranial calcifications out of 16 patients with ECM1 mutations and investigated the semiologic features, ictal and interictal EEG findings, and long-term prognosis of epilepsy in this genodermatosis...
April 1, 2017: Clinical EEG and Neuroscience: Official Journal of the EEG and Clinical Neuroscience Society (ENCS)
https://www.readbyqxmd.com/read/28434149/solvent-dependent-transformation-of-aflatoxin-b1-in-soil
#18
James M Starr, Blake R Rushing, Mustafa I Selim
To date, all studies of aflatoxin B1 (AFB1) transformation in soil or in purified mineral systems have identified aflatoxins B2 (AFB2) and G2 (AFG2) as the primary transformation products. However, identification in these studies was made using thin layer chromatography which has relatively low resolution, and these studies did not identify a viable mechanism by which such transformations would occur. Further, the use of methanol as the solvent delivery vehicle in these studies may have contributed to formation of artifactual transformation products...
April 22, 2017: Mycotoxin Research
https://www.readbyqxmd.com/read/28433595/effects-of-chlorpyrifos-on-soil-carboxylesterase-activity-at-an-aggregate-size-scale
#19
Juan C Sanchez-Hernandez, Marco Sandoval
The impact of pesticides on extracellular enzyme activity has been mostly studied on the bulk soil scale, and our understanding of the impact on an aggregate-size scale remains limited. Because microbial processes, and their extracellular enzyme production, are dependent on the size of soil aggregates, we hypothesized that the effect of pesticides on enzyme activities is aggregate-size specific. We performed three experiments using an Andisol to test the interaction between carboxylesterase (CbE) activity and the organophosphorus (OP) chlorpyrifos...
April 20, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28433579/distinguishing-septic-from-normal-donors-by-detection-of-spla2-iia-from-human-plasma-using-a-microsieve-based-immunoassay
#20
Daniel R Zweitzig, Arjan G Tibbe, Mark J Kopnitsky, Kathleen Cichonski, Leon W M M Terstappen
Bloodstream infections that progress to septic shock are responsible for hundreds of thousands of deaths each year, and are associated with significant healthcare costs. Recent studies have shown that a member of the secreted phospholipase protein family, termed sPLA2-IIA, may play a role during the innate immune response to bacterial infections, and is elevated in the plasma of septic patients. In this report, the feasibility of a simple microsieve-based sPLA2-IIA detection immunoassay was explored. Microsieves containing 5μm pores were covalently coupled with a sPLA2-IIA-specific monoclonal antibody at 0...
April 19, 2017: Journal of Immunological Methods
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