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1.
Sci Rep ; 11(1): 14516, 2021 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-34267288

RESUMEN

Bacterial culture of M. tuberculosis (MTB), the causative agent of tuberculosis (TB), from clinical specimens is the gold standard for laboratory diagnosis of TB, but is slow and culture-negative TB cases are common. Alternative immune-based and molecular approaches have been developed, but cannot discriminate between active TB (ATB) and latent TB (LTBI). Here, to identify biomarkers that can discriminate between ATB and LTBI/healthy individuals (HC), we profiled 116 serum samples (HC, LTBI and ATB) using a protein microarray containing 257 MTB secreted proteins, identifying 23 antibodies against MTB antigens that were present at significantly higher levels in patients with ATB than in those with LTBI and HC (Fold change > 1.2; p < 0.05). A 4-protein biomarker panel (Rv0934, Rv3881c, Rv1860 and Rv1827), optimized using SAM and ROC analysis, had a sensitivity of 67.3% and specificity of 91.2% for distinguishing ATB from LTBI, and 71.2% sensitivity and 96.3% specificity for distinguishing ATB from HC. Validation of the four candidate biomarkers in ELISA assays using 440 serum samples gave consistent results. The promising sensitivity and specificity of this biomarker panel suggest it merits further investigation for its potential as a diagnostic for discriminating between latent and active TB.


Asunto(s)
Proteínas Bacterianas/sangre , Biomarcadores/sangre , Tuberculosis Latente/sangre , Tuberculosis Pulmonar/sangre , Adolescente , Adulto , Anciano , Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos/inmunología , Proteínas Bacterianas/genética , Proteínas Bacterianas/inmunología , Femenino , Humanos , Tuberculosis Latente/diagnóstico , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis/inmunología , Análisis por Matrices de Proteínas/métodos , Mapas de Interacción de Proteínas/genética , Sensibilidad y Especificidad , Tuberculosis Pulmonar/diagnóstico , Adulto Joven
2.
Front Plant Sci ; 12: 580825, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33679821

RESUMEN

There is a growing consensus on soil conservation by mechanics of plant root system. In order to further study how root system exerts its mechanical properties during soil reinforcing process and which morphological indicator is suitable for reflecting pullout resistance, in-situ vertical pullout test (VPT) and 45° oblique pullout test (OPT) were performed on alfalfa (Medicago sativa L.) roots in the loess area. The results showed that the failure mode of alfalfa roots was pulling out in this study. The peak pullout resistance of the roots increased with root diameter, root length and root surface area, and power law relationships were observed between the pullout resistance and the morphological indices: root diameter, root length and root surface area. The maximum gray relational degree of the morphological indices was 0.841 (VPT) and 0.849 (OPT) for root surface area, suggesting that root surface area was a more significant root morphological index affecting root pullout resistance than root diameter and root length, and was more suitable for characterizing the difference in peak pullout resistance of roots with different size. The index could be used to validate the methods for predicting root pullout capacity. The value of peak pullout resistance was 17.2 ± 2.3 N in VPT test and 28.2 ± 3.8 N (mean ± SE) in OPT test, and a significant difference was observed between the two tests, which showed that the pulling direction significantly affected the peak pullout resistance of alfalfa roots. Vertical pullout test, giving the safety margin, was suggested to determine root pullout resistance for estimate of root reinforcement.

3.
J Chem Theory Comput ; 15(12): 6588-6596, 2019 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-31638803

RESUMEN

We report a polarizable subsystem density functional theory to describe electronic properties of molecules embedded on a metal cluster. Interaction between the molecule and metal cluster is described using frozen density embedding (FDE). Substituting the nonadditive kinetic potential (NAKP) by approximate functionals is circumvented by enforcing external orthogonality (EO) through a projection operator. The computationally expensive freeze/thaw (FT) cycles are bypassed by including a polarization term in the embedding operator. Furthermore, the combination of polarization and EO permits supermolecular basis set calculations, which was not possible for strongly interacting systems with existing kinetic energy functionals. To test the method, we described the ground state density of pyridine, water, and benzene on a silver cluster. Performing FT on top of EO results in exact density embedding for this category of systems and is thus used for benchmarking the method. We find that the density is reproduced to within 0.15e, and the dipole and quadrupole moments are within 18% of the reference points for subsystem separations ranging from bonding to noninteracting distances. Additionally, our formalism allows the flexibility of incorporating different density functionals to the molecular and the metallic subsystems reducing the overall computational cost.

4.
ACS Nano ; 13(8): 9342-9351, 2019 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-31313907

RESUMEN

Vibrational modes of a single molecule can be visualized by tip-enhanced Raman spectroscopy with atomic resolution. However, the exact vibrations associated with these Raman scattering images are still in debate due to the lack of theoretical interpretation. In this work, we systematically study the Raman scattering images of a single Co(II)-tetraphenylporphyrin molecule. The stable structure whose Raman scattering images consistently match experimental results is discovered. Furthermore, we elucidate the effects of near-field localizations and field gradient on the resolution in Raman scattering images. The approach of locally integrated Raman polarizability density employed in this work provides an intuitive explanation of the origin of the experimental Raman scattering images.

5.
Nat Commun ; 10(1): 2567, 2019 06 12.
Artículo en Inglés | MEDLINE | ID: mdl-31189893

RESUMEN

Tip-enhanced Raman spectroscopy (TERS) exhibits new selection rule and sub-nanometer spatial resolution, which is attributed to the plasmonic near-field confinement. Despite recent advances in simulations of TERS spectra under highly confined fields, a simply physical mechanism has remained elusive. In this work we show that single-molecule TERS images can be explained by local sub-molecular density changes induced by the confined near-field during the Raman process. The local sub-molecular density changes determine the spatial resolution in TERS and the gradient-based selection rule. Using this approach we find that the four-fold symmetry of meso-tetrakis(3,5-di-tert-butylphenyl)porphyrin (H2TBPP) TERS images observed in experiments arises from the combination of degenerate normal modes localized in the functional side groups rather than the porphyrin ring as previously considered. As an illustration of the potential of the method, we demonstrate how this new theory can be applied to microscopic structure characterization.

6.
Nanotechnology ; 29(32): 325301, 2018 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-29767633

RESUMEN

Field-emitted, low-energy electrons from the conducting tip of an atomic force microscope were adopted for nanolithography on calixarene ultrathin films coated on silicon wafers. A structural evolution from protrusion to depression down to a 30 nm spatial resolution was reproducibly obtained by tuning the sample voltage and exposure current in the lithography process. Close analyses of the profiles showed that the nanostructures formed by a single exposure with a high current are almost identical to those created by cumulative exposure with a lower current but an equal number of injected electrons. Surface potential imaging by Kelvin probe force microscopy found a negatively charged region surrounding the groove structures once the structures were formed. We conclude that the mechanism related to the formation of a temporary negative state and molecule decomposition, rather than thermal ablation, is responsible for the low-energy field-emission electron lithography on a calixarene molecular resist. We hope that our elucidation of the underlying mechanism is helpful for molecular resist design and further improving the reproducibility and throughput of nanolithography.

7.
ACS Nano ; 11(11): 11466-11474, 2017 11 28.
Artículo en Inglés | MEDLINE | ID: mdl-28976729

RESUMEN

Atomically terminated and nanoscopically smooth silver tips effectively focus light on the angstrom scale, allowing tip-enhanced Raman spectromicroscopy (TER-sm) with single molecule sensitivity and submolecular spatial resolution. Through measurements carried out on cobalt-tetraphenylporphyrin (CoTPP) adsorbed on Au(111), we highlight peculiarities of vibrational spectromicroscopy with light confined on the angstrom scale. Field-gradient-driven spectra, orientational fingerprinting, and sculpting of local fields by atomic morphology of the junction are elucidated through measurements that range from 2D arrays at room temperature to single molecule manipulations at 5 K. Notably, vibrational Stark tuning within molecules, reflecting intramolecular charge distributions, becomes accessible when light is more localized than the interrogated normal modes. The Stark images of CoTPP reveal that it is saddled, and the distortion is accompanied by charge transfer to gold through the two anchoring pyrroles.

8.
ACS Nano ; 11(5): 5094-5102, 2017 05 23.
Artículo en Inglés | MEDLINE | ID: mdl-28463555

RESUMEN

Advances in tip-enhanced Raman spectroscopy (TERS) have demonstrated ultrahigh spatial resolution so that the vibrational modes of individual molecules can be visualized. The spatial resolution of TERS is determined by the confinement of the plasmon-induced field in the junction; however, the conditions necessary for achieving the high spatial confinement required for imaging individual molecules are not fully understood. Here, we present a systematic theoretical study of TERS imaging of single molecules, using a hybrid atomistic electrodynamics-quantum mechanical method. This approach provides a consistent treatment of the molecule and the plasmonic near field under conditions where they cannot be treated separately. In our simulations, we demonstrate that TERS is capable of resolving intricate molecule vibrations with atomic resolution, although we find that TERS images are extremely sensitive to the near field in the junction. Achieving the atomic resolution requires the near field to be confined within a few ångstroms in diameter and the near-field focal plane to be in the molecule plane. Furthermore, we demonstrate that the traditional surface selection rule of Raman spectroscopy is altered due to the significant field confinement that leads to significant field-gradient effects in the Raman scattering. This work provides insights into single-molecule imaging based on TERS and Raman scattering of molecules in nanojunctions with atomic dimensions.

9.
Immunol Res ; 61(3): 281-93, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25608796

RESUMEN

Staphylococcal enterotoxins (SEs) produced by Staphylococcus aureus have increasingly given rise to human health and food safety. Genetically engineered small molecular antibody is a useful tool in immuno-detection and treatment for clinical illness caused by SEs. In this study, we constructed the V(L)-V(H) tail-parallel genetically engineered antibody against SEs by using the repertoire of rearranged germ-line immunoglobulin variable region genes. Total RNA were extracted from six hybridoma cell lines that stably express anti-SEs antibodies. The variable region genes of light chain (V(L)) and heavy chain (V(H)) were cloned by reverse transcription PCR, and their classical murine antibody structure and functional V(D)J gene rearrangement were analyzed. To construct the eukaryotic V(H)-V(L) tail-parallel co-expression vectors based on the "5'-V(H)-ivs-IRES-V(L)-3'" mode, the ivs-IRES fragment and V(L) genes were spliced by two-step overlap extension PCR, and then, the recombined gene fragment and V(H) genes were inserted into the pcDNA3.1(+) expression vector sequentially. And then the constructed eukaryotic expression clones termed as p2C2HILO and p5C12HILO were transfected into baby hamster kidney 21 cell line, respectively. Two clonal cell lines stably expressing V(L)-V(H) tail-parallel antibodies against SEs were obtained, and the antibodies that expressed intracytoplasma were evaluated by enzyme-linked immunosorbent assay, immunofluorescence assay, and flow cytometry. SEs can stimulate the expression of some chemokines and chemokine receptors in porcine IPEC-J2 cells; mRNA transcription level of four chemokines and chemokine receptors can be blocked by the recombinant SE antibody prepared in this study. Our results showed that it is possible to get functional V(L)-V(H) tail-parallel genetically engineered antibodies in same vector using eukaryotic expression system.


Asunto(s)
Anticuerpos Antibacterianos/administración & dosificación , Inmunoterapia/métodos , Mucosa Intestinal/fisiología , Proteínas Recombinantes/administración & dosificación , Intoxicación Alimentaria Estafilocócica/terapia , Infecciones Estafilocócicas/inmunología , Staphylococcus aureus/fisiología , Animales , Línea Celular , Cricetinae , Enterotoxinas/inmunología , Humanos , Región Variable de Inmunoglobulina/genética , Mucosa Intestinal/efectos de los fármacos , Ingeniería de Proteínas , Intoxicación Alimentaria Estafilocócica/inmunología , Sus scrofa
10.
Nat Neurosci ; 9(1): 41-9, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16341213

RESUMEN

High-conductance, Ca(2+)-activated and voltage-gated (BK) channels set neuronal firing. They are almost universally activated by alcohol, leading to reduced neuronal excitability and neuropeptide release and to motor intoxication. However, several BK channels are inhibited by alcohol, and most other voltage-gated K(+) channels are refractory to drug action. BK channels are homotetramers (encoded by Slo1) that possess a unique transmembrane segment (S0), leading to a cytosolic S0-S1 loop. We identified Thr107 of bovine slo (bslo) in this loop as a critical residue that determines BK channel responses to alcohol. In addition, the activity of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in the cell controlled channel activity and alcohol modulation. Incremental CaMKII-mediated phosphorylation of Thr107 in the BK tetramer progressively increased channel activity and gradually switched the channel alcohol responses from robust activation to inhibition. Thus, CaMKII phosphorylation of slo Thr107 works as a 'molecular dimmer switch' that could mediate tolerance to alcohol, a form of neuronal plasticity.


Asunto(s)
Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Depresores del Sistema Nervioso Central/farmacología , Etanol/farmacología , Subunidades alfa de los Canales de Potasio de Gran Conductancia Activados por Calcio/efectos de los fármacos , Subunidades alfa de los Canales de Potasio de Gran Conductancia Activados por Calcio/fisiología , Canales de Potasio de Gran Conductancia Activados por el Calcio/efectos de los fármacos , Treonina/metabolismo , Fosfatasa Alcalina/química , Secuencia de Aminoácidos , Animales , Bencilaminas/farmacología , Bradiquinina/fisiología , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina , Proteínas Quinasas Dependientes de Calcio-Calmodulina/genética , Electrofisiología , Canales de Potasio de Gran Conductancia Activados por el Calcio/genética , Ratones , Datos de Secuencia Molecular , Mutagénesis , Oocitos/efectos de los fármacos , Oocitos/metabolismo , Técnicas de Placa-Clamp , Fosfoproteínas Fosfatasas/metabolismo , Fosforilación , ARN Complementario/biosíntesis , ARN Complementario/genética , Sulfonamidas/farmacología , Treonina/genética , Xenopus
11.
Proc Natl Acad Sci U S A ; 101(52): 18217-22, 2004 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-15604147

RESUMEN

Binge drinking is associated with increased risk for cerebrovascular spasm and stroke. Acute exposure to ethanol at concentrations obtained during binge drinking constricts cerebral arteries in several species, including humans, but the mechanisms underlying this action are largely unknown. In a rodent model, we used fluorescence microscopy, patch-clamp electrophysiology, and pharmacological studies in intact cerebral arteries to pinpoint the molecular effectors of ethanol cerebrovascular constriction. Clinically relevant concentrations of ethanol elevated wall intracellular Ca(2+) concentration and caused a reversible constriction of cerebral arteries (EC(50) = 27 mM; E(max) = 100 mM) that depended on voltage-gated Ca(2+) entry into myocytes. However, ethanol did not directly increase voltage-dependent Ca(2+) currents in isolated myocytes. Constriction occurred because of an ethanol reduction in the frequency (-53%) and amplitude (-32%) of transient Ca(2+)-activated K(+) (BK) currents. Ethanol inhibition of BK transients was caused by a reduction in Ca(2+) spark frequency (-49%), a subsarcolemmal Ca(2+) signal that evokes the BK transients, and a direct inhibition of BK channel steady-state activity (-44%). In contrast, ethanol failed to modify Ca(2+) waves, a major vasoconstrictor mechanism. Selective block of BK channels largely prevented ethanol constriction in pressurized arteries. This study pinpoints the Ca(2+) spark/BK channel negative-feedback mechanism as the primary effector of ethanol vasoconstriction.


Asunto(s)
Depresores del Sistema Nervioso Central/farmacología , Arterias Cerebrales/patología , Etanol/efectos adversos , Músculo Liso/metabolismo , Canales de Potasio Calcio-Activados/fisiología , Vasoconstricción , Animales , Calcio/metabolismo , Señalización del Calcio , Células Cultivadas , Arterias Cerebrales/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Electrofisiología , Etanol/farmacología , Canales de Potasio de Gran Conductancia Activados por el Calcio , Masculino , Microscopía Fluorescente , Células Musculares/efectos de los fármacos , Canales de Potasio/metabolismo , Canales de Potasio Calcio-Activados/metabolismo , Ratas , Ratas Sprague-Dawley , Factores de Tiempo
12.
Acta Pharmacol Sin ; 24(12): 1205-11, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14653945

RESUMEN

AIM: To study the expression of collapsing response mediated protein-4 (CRMP-4) and nestin in the ischemic adult rat brain following transient brain ischemia. METHODS: Brain ischemia was induced by transient left middle cerebral artery occlusion (MCAO) for 60 min in adult rats. The expression of CRMP-4, nestin and bromodeoxyuridine (BrdU) was analyzed by immunohistochemical method. The co-localization of CRMP-4 and nestin or BrdU was analyzed by double staining combined with confocal laser scanning microscopy. RESULTS: CRMP-4, a marker of immature neuron, could be expressed in the ipsilateral striatum and cerebral cortex at 1st and 2nd week after the ischemia-reperfusion; nestin, a marker of neural stem cell, occurred in above regions from several hours to 2 weeks. CRMP-4 costained with nestin and with BrdU incorporation. CONCLUSION: Neural stem cells may present in the striatum and cerebral cortex of adult rat and can be triggered to differentiate into newborn neuron there by ischemic brain trauma.


Asunto(s)
Cuerpo Estriado/metabolismo , Ataque Isquémico Transitorio/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Animales , Bromodesoxiuridina/metabolismo , Corteza Cerebral/metabolismo , Proteínas de Filamentos Intermediarios/metabolismo , Ataque Isquémico Transitorio/complicaciones , Masculino , Nestina , Ratas , Ratas Sprague-Dawley
13.
Alcohol Clin Exp Res ; 27(10): 1640-4, 2003 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-14574235

RESUMEN

BACKGROUND: Ethanol at clinically relevant concentrations increases BKCa channel activity in dorsal root ganglia neurons, GH3 cells, and neurohypophysial terminals, leading to decreases in cell excitability and peptide release. In contrast, ethanol inhibits BKCa channels from aortic myocytes, which likely contributes to alcohol-induced aortic constriction. The mechanisms that determine differential BKCa channel responses to ethanol are unknown. We hypothesized that nonconserved regions in the BKCa channel-forming subunit (slo) are major contributors to the differential alcohol responses of different BKCa channel phenotypes. METHODS: We constructed chimeras by interchanging the core and the tail domains of two BKCa channel-forming subunits (mslo and bslo) that, after expression, differentially respond to ethanol (activation and inhibition, respectively), and studied ethanol action on these mbslo and bmslo chimeric channels using single-channel, patch-clamp techniques. RESULTS AND CONCLUSION: Data from cell-free membranes patches demonstrate that the activity of channels that share a mslo-type core-linker (wt mslo and the mbslo chimera) is consistently and significantly potentiated by acute exposure to ethanol. Thus, a mslo tail is not necessary for ethanol potentiation of slo channels. In contrast, the activity of channels that share a bslo-type core-linker (wt bslo and the bmslo chimera) display heterogenous responses to ethanol: inhibition (in the majority of cases), refractoriness, or activation. Overall, our data indicate that the slo core-linker is a critical region likely contributing to the differential responses of BKCa channels to ethanol.


Asunto(s)
Etanol/farmacología , Canales de Potasio Calcio-Activados/biosíntesis , Canales de Potasio Calcio-Activados/química , Subunidades de Proteína/biosíntesis , Subunidades de Proteína/química , Animales , Femenino , Canales de Potasio de Gran Conductancia Activados por el Calcio , Canales de Potasio Calcio-Activados/genética , Subunidades de Proteína/genética , Xenopus laevis
14.
Sheng Li Xue Bao ; 54(4): 294-9, 2002 Aug 25.
Artículo en Chino | MEDLINE | ID: mdl-12195276

RESUMEN

Immunohistochemistry and double immunofluorescent labeling techniques combined with confocal laser scanning microscope analysis were used to investigate the characteristic spatial induction profile of nestin following a transient middle cerebral artery occlusion in adult rat brain. The results showed that nestin was induced in ischemic core at 1 day after reperfusion. In addition to ischemic core, the expression of nestin increased in peri-ischemic I, II and III regions at 3 days and 1 week, then it decreased and narrowed along the rim of ischemic core 2 weeks after reperfusion. Double immunofluorescent labeling showed that nestin positive cells were mostly co-stained with GFAP,a astrocyte marker, in peri-ischemic I region 3 days after reperfusion. At 2 weeks, however nestin cells showed a long process and the cells double stained with nestin and NSE,a neuonal specific marker,increased in the ischemic brain. The results suggest that cerebral ischemia induces nestin expression in damaged neurons which might favor the neuroprotection against ischemic damage.


Asunto(s)
Isquemia Encefálica/metabolismo , Encéfalo/metabolismo , Nestina/metabolismo , Neuronas/metabolismo , Animales , Encéfalo/patología , Isquemia Encefálica/patología , Inmunohistoquímica , Infarto de la Arteria Cerebral Media/metabolismo , Infarto de la Arteria Cerebral Media/patología , Ratas
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