38 research outputs found
Lifespan gyrification trajectories of human brain in healthy individuals and patients with major psychiatric disorders
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Contralesional Cortical Structural Reorganization Contributes to Motor Recovery after Sub-Cortical Stroke: A Longitudinal Voxel-Based Morphometry Study
Although changes in brain gray matter after stroke have been identified in some neuroimaging studies, lesion heterogeneity and individual variability make the detection of potential neuronal reorganization difficult. This study attempted to investigate the potential structural cortical reorganization after sub-cortical stroke using a longitudinal voxel-based gray matter volume (GMV) analysis. Eleven right-handed patients with first -onset, subcortical, ischemic infarctions involving the basal ganglia regions underwent structural magnetic resonance imaging in addition to National Institutes of Health Stroke Scale and Motricity Index assessments in the acute (< 5 days) and chronic stages (1 year later). The GMVs were calculated and compared between the two stages using nonparametric permutation paired t tests. Moreover, the Spearman correlations between the GMV changes and clinical recoveries were analyzed. Compared with the acute stage, significant decreases in GMV were observed in the ipsilesional precentral gyrus (PreCG), paracentral gyrus, and contralesional cerebellar lobule VII in the chronic stage. Additionally, significant increases in GMV were found in the contralesional orbitofrontal cortex (OFC) and middle (MFG) and inferior (IFG) frontal gyri. Furthermore, severe GMV atrophy in the ipsilesional PreCG predicted poorer clinical recovery, and greater GMV increases in the contralesional OFG and MFG predicted better clinical recovery. Our findings suggest that structural reorganization of the contralesional ācognitiveā cortices might contribute to motor recovery after sub-cortical stroke
Target-Induced Nano-Enzyme Reactor Mediated Hole-Trapping for High-Throughput Immunoassay Based on a Split-Type Photoelectrochemical Detection Strategy
Photoelectrochemical (PEC) detection
is an emerging and promising
analytical tool. However, its actual application still faces some
challenges like potential damage of biomolecules (caused by itself
system) and intrinsic low-throughput detection. To solve the problems,
herein we design a novel split-type photoelectrochemical immunoassay
(STPIA) for ultrasensitive detection of prostate specific antigen
(PSA). Initially, the immunoreaction was performed on a microplate
using a secondary antibody/primer-circular DNA-labeled gold nanoparticle
as the detection tag. Then, numerously repeated oligonucleotide sequences
with many biotin moieties were in situ synthesized on the nanogold
tag via RCA reaction. The formed biotin concatamers acted as a powerful
scaffold to bind with avidin-alkaline phosphatase (ALP) conjugates
and construct a nanoenzyme reactor. By this means, enzymatic hydrolysate
(ascorbic acid) was generated to capture the photogenerated holes
in the CdS quantum dot-sensitized TiO<sub>2</sub> nanotube arrays,
resulting in amplification of the photocurrent signal. To elaborate,
the microplate-based immunoassay and the high-throughput detection
system, a semiautomatic detection cell (installed with a three-electrode
system), was employed. Under optimal conditions, the photocurrent
increased with the increasing PSA concentration in a dynamic working
range from 0.001 to 3 ng mL<sup>ā1</sup>, with a low detection
limit (LOD) of 0.32 pg mL<sup>ā1</sup>. Meanwhile, the developed
split-type photoelectrochemical immunoassay exhibited high specificity
and acceptable accuracy for analysis of human serum specimens in comparison
with referenced electrochemiluminescence immunoassay method. Importantly,
the system was not only suitable for the sandwich-type immunoassay
mode, but also utilized for the detection of small molecules (e.g.,
aflatoxin B<sub>1</sub>) with a competitive-type assay format
Plasmonic AuNP/gāC<sub>3</sub>N<sub>4</sub> Nanohybrid-based Photoelectrochemical Sensing Platform for Ultrasensitive Monitoring of Polynucleotide Kinase Activity Accompanying DNAzyme-Catalyzed Precipitation Amplification
A convenient and feasible photoelectrochemical
(PEC) sensing platform
based on gold nanoparticles-decorated g-C<sub>3</sub>N<sub>4</sub> nanosheets (AuNP/g-C<sub>3</sub>N<sub>4</sub>) was designed for
highly sensitive monitoring of T4 polynucleotide kinase (PNK) activity,
using DNAzyme-mediated catalytic precipitation amplification. To realize
our design, the AuNP/g-C<sub>3</sub>N<sub>4</sub> nanohybrid was initially
synthesized through in situ reduction of AuĀ(III) on the g-C<sub>3</sub>N<sub>4</sub> nanosheets, which was utilized for the immobilization
of hairpin DNA<sub>1</sub> (HP<sub>1</sub>) on the sensing interface.
Thereafter, a target-induced isothermal amplification was automatically
carried out on hairpin DNA<sub>2</sub> (HP<sub>2</sub>) in the solution
phase through PNK-catalyzed 5ā²-phosphorylation accompanying
formation of numerous trigger DNA fragments, which could induce generation
of hemin/G-quadruplex-based DNAzyme on hairpin DNA<sub>1</sub>. Subsequently,
the DNAzyme could catalyze the 4-chloro-1-naphthol (4-CN) oxidation
to produce an insoluble precipitation on the AuNP/g-C<sub>3</sub>N<sub>4</sub> surface, thereby resulting in the local alternation of the
photocurrent. Experimental results revealed that introduction of AuNP
on the g-C<sub>3</sub>N<sub>4</sub> could cause a ā¼100% increase
in the photocurrent because of surface plasmon resonance-enhanced
light harvesting and separation of photogenerated e<sup>ā</sup>/h<sup>+</sup> pairs. Under the optimal conditions, the percentage
of photocurrent decrement (Ī<i>I</i>/<i>I</i><sub>0</sub>, relative to background signal) increased with the increasing
PNK activity in a dynamic working range from 2 to 100 mU mL<sup>ā1</sup> with a low detection limit (LOD) of 1.0 mU mL<sup>ā1</sup>. The inhibition effect of adenosine diphosphate also received a
good performance in PNK inhibitor screening research, thereby providing
a useful scheme for practical use in quantitative PNK activity assay
for life science and biological research
High-Resolution Colorimetric Assay for Rapid Visual Readout of Phosphatase Activity Based on Gold/Silver Core/Shell Nanorod
Nanostructure-based visual assay
has been developed for determination
of enzymatic activity, but most involve in poor visible color resolution
and are not suitable for routine utilization. Herein, we designed
a high-resolution colorimetric protocol based on gold/silver core/shell
nanorod for visual readout of alkaline phosphatase (ALP) activity
by using bare-eyes. The method relied on enzymatic reaction-assisted
silver deposition on gold nanorod to generate significant color change,
which was strongly dependent on ALP activity. Upon target ALP introduction
into the substrate, the ascorbic acid 2-phosphate was hydrolyzed to
form ascorbic acid, and then, the generated ascorbic acid reduced
silver ion to metal silver and coated on the gold nanorod, thereby
resulting in the blue shift of longitudinal localized surface plasmon
resonance peak of gold nanorod accompanying a perceptible color change
from red to orange to yellow to green to cyan to blue and to violet.
Under optimal conditions, the designed method exhibited the wide linear
range 5ā100 mU mL<sup>ā1</sup> ALP with a detection
limit of 3.3 mU mL<sup>ā1</sup>. Moreover, it could be used
for the semiquantitative detection of ALP from 20 to 500 mU mL<sup>ā1</sup> by using the bare-eyes. The coefficients of variation
for intra- and interassay were below 3.5% and 6.2%, respectively.
Finally, this method was validated for the analysis of real-life serum
samples, giving results matched well with those from the 4-nitrophenyl
phosphate disodium salt hexahydrate (pNPP)-based standard method.
In addition, the system could even be utilized in the enzyme-linked
immunosorbent assay (ELISA) to detect IgG at picomol concentration.
With the merits of simplification, low cost, user-friendliness, and
sensitive readout, the gold nanorod-based colorimetric assay has the
potential to be utilized by the public and opens a new horizon for
bioassays
Lifespan gyrification trajectories of human brain in healthy individuals and patients with major psychiatric disorders
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Ultrasensitive and Specific Phage@DNAzyme Probe-Triggered Fluorescent Click Chemistry for On-Site Detection of Foodborne Pathogens Using a Smartphone
Rapid, specific, and on-site detection of virulent foodborne
pathogenic
strains plays a key role in controlling food safety. In this work,
an ultrasensitive and specific Phage@DNAzyme signal probe was designed
to detect foodborne pathogens. The proposed sensing probe was composed
of the selected phage and functionalized DNAzyme, which realized the
specific recognition of target foodborne pathogens at the strain level
and the efficient catalysis of copper(II) based azide-alkyne cycloaddition
(CuAAC) click reaction with fluorescent signal, respectively. As a
proof of concept, the virulent Escherichia coli O157:H7 (E. coli O157:H7) as the
representative analyte was first enriched and purified from the complex
food samples by a 4-mercaptophenylboronic acid-modified gold slide.
Following, the Phage@DNAzyme probes were specifically combined with
the captured E. coli O157: H7 and catalyzed
the click reaction between 3-azido-7-hydroxycoumarin and 3-butyn-1-ol
with the assistance of Cu(II) to generate a visual fluorescent signal.
Finally, the corresponding fluorescent signals were measured by a
smartphone to quantify the target concentrations. Under optimized
conditions, the bioassay exhibited a wide linear range from 102 to 108 CFU/mL and the detection limit was 50 CFU/mL
(S/N = 3). It was further extended
to the detection of another foodborne pathogen Salmonella
typhimurium with satisfying sensing performances.
This work gives a new path for developing rapid, specific, and on-site
detection methods for trace levels of pathogenic strains in foods
Enhanced virus resistance in transgenic maize expressing a dsRNA-specific endoribonuclease gene from E. coli.
Maize rough dwarf disease (MRDD), caused by several Fijiviruses in the family Reoviridae, is a global disease that is responsible for substantial yield losses in maize. Although some maize germplasm have low levels of polygenic resistance to MRDD, highly resistant cultivated varieties are not available for agronomic field production in China. In this work, we have generated transgenic maize lines that constitutively express rnc70, a mutant E. coli dsRNA-specific endoribonuclease gene. Transgenic lines were propagated and screened under field conditions for 12 generations. During three years of evaluations, two transgenic lines and their progeny were challenged with Rice black-streaked dwarf virus (RBSDV), the causal agent of MRDD in China, and these plants exhibited reduced levels of disease severity. In two normal years of MRDD abundance, both lines were more resistant than non-transgenic plants. Even in the most serious MRDD year, six out of seven progeny from one line were resistant, whereas non-transgenic plants were highly susceptible. Molecular approaches in the T12 generation revealed that the rnc70 transgene was integrated and expressed stably in transgenic lines. Under artificial conditions permitting heavy virus inoculation, the T12 progeny of two highly resistant lines had a reduced incidence of MRDD and accumulation of RBSDV in infected plants. In addition, we confirmed that the RNC70 protein could bind directly to RBSDV dsRNA in vitro. Overall, our data show that RNC70-mediated resistance in transgenic maize can provide efficient protection against dsRNA virus infection