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2.
Small ; : e2000041, 2020 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-32452636

RESUMO

Artificial synapses (ASs) are electronic devices emulating important functions of biological synapses, which are essential building blocks of artificial neuromorphic networks for brain-inspired computing. A human brain consists of several quadrillion synapses for information storage and processing, and massively parallel computation. Neuromorphic systems require ASs to mimic biological synaptic functions, such as paired-pulse facilitation, short-term potentiation, long-term potentiation, spatiotemporally-correlated signal processing, and spike-timing-dependent plasticity, etc. Feature size and energy consumption of ASs need to be minimized for high-density energy-efficient integration. This work reviews recent progress on ASs. First, synaptic plasticity and functional emulation are introduced, and then synaptic electronic devices for neuromorphic computing systems are discussed. Recent advances in flexible artificial synapses for artificial sensory nerves are also briefly introduced. Finally, challenges and opportunities in the field are discussed.

3.
Ecotoxicol Environ Saf ; 198: 110596, 2020 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-32353602

RESUMO

Aflatoxin B1 (AFB1) is a known carcinogen found in contaminated food and designated by the World Health Organization as a class I carcinogenic substance. AFB1 presents with carcinogenicity, teratogenicity, and mutagenicity, and the liver is the human organ most susceptible to AFB1. Zinc (Zn), which is one of the essential nutrient elements that could protect the cells from biological toxins, heavy metals, hydrogen peroxide, metal chelators and radiation, is assessed in this study for its potential to alleviate AFB1-induced cytotoxicity. Samples were divided into three groups, namely CK, AFB1, and AFB1+Zn. Protein expressions were analyzed by two-way electrophoresis combined with flight mass spectrometry, with 41 differentially expressed proteins identified in the results, mainly related to oxidative stress, cell apoptosis, DNA damage, and energy metabolism. Zn was found to regulate the expression of peroxidases (peroxiredoxin-1, peroxiredoxin-5, peroxiredoxin-6) to relieve AFB1-induced oxidative stress. Moreover, Zn could decrease the expression of pro-apoptotic genes (cleaved-caspase-3, caspase-9, and Bax) and increase the expression of anti-apoptotic genes (Bcl-2 and Bcl-xl) to alleviate the cell apoptosis induced by AFB1. In addition, AFB1 reduced intracellular ATP levels, whereas Zn supplementation boosted ATP levels and maintained homeostasis and a steady state of cellular energy metabolism by modulating AMPK-ACC phosphorylation levels, while many zinc finger proteins changed after AFB1 treatment. These results, therefore, indicate that Zn could alleviate AFB1-induced cytotoxicity by changing the expressions of zinc finger proteins in liver hepatocellular carcinoma (HepG2 cells).

4.
iScience ; 23(5): 101113, 2020 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-32413611

RESUMO

Brown adipose tissue (BAT) is a promising potential therapeutic target for the treatment of obesity and related metabolic diseases. Allicin, a natural product in garlic, has multiple biological and pharmacological functions. However, the role of allicin in the regulation of metabolic organs, particularly BAT activation, has not been well studied. Here, we show that allicin imparts a significant effect by inhibiting body weight gain, decreasing adiposity, maintaining glucose homeostasis, improving insulin resistance, and ameliorating hepatic steatosis in obese mice. These observations strongly correlate with the activation of BAT. Notably, allicin plays a role in BAT activation, which may partly contribute to the Sirt1-PGC1α-Tfam pathway. In addition, allicin can significantly increase the succinylation levels of UCP1 in BAT by inhibiting sirt5, whereas excess allicin induces autophagy/mitophagy and mitochondrial dysfunction. Thus, our findings point to allicin as a promising therapeutic approach for the treatment of obesity and metabolic disorders.

5.
Food Chem ; 324: 126859, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32344343

RESUMO

Here, we constructed a fast, universal, "turn-on" biosensor for the highly sensitive visual detection of Salmonella based on luminescent DNAzyme and a universal blocking linker Super Polymerase Chain Reaction (S-PCR). The primer in this biosensor was specially designed. The G-quadruplex sequence is attached to the 5' end of the primer by a blocking linker and is blocked in the stem part. The S-PCR amplification releases the G-quadruplex, which is incubated with hemin to form DNAzyme to exert peroxide-like activity. The visible colored products are generated by the addition of 3,3',5,5'-Tetramethylbenzidine. Detection sensitivity is high and, even when the concentration of the Salmonella genome in a sample is as low as 1.5 copies/µL, this color change can be seen with the naked eyes. Moreover, this method is simple and fast, as the S-PCR can be completed in less than 10 min using the newly built equipment and without the need for large instruments.

6.
Small ; : e1905332, 2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32243063

RESUMO

Flexible transistor-structured memory (FTSM) has attracted great attention for its important role in flexible electronics. For nonvolatile information storage, FTSMs with floating-gate, charge-trap, and ferroelectric mechanisms have been developed. By introducing an optical sensory module, FTSM can be operated by optical inputs to function as an optical memory transistor. As a special type of FTSM, transistor-structured artificial synapse emulates important functions of a biological synapse to mimic brain-inspired memory behaviors and nervous signal transmissions. This work reviews the recent development of the above mentioned FTSMs, with a focus on working mechanism and materials, and flexibility.

7.
J Agric Food Chem ; 68(20): 5555-5571, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32343564

RESUMO

On the basis of the mechanism of acylhydrazone compounds inhibiting the assembly of TMV CP and the unique structural characteristics of diketopiperazine ring, a series of optically pure indole diketopiperazine acylhydrazone were designed and synthesized. In order to systematically study the effect of the spatial configuration of the compounds on the antiviral activity, four compounds with different spatial configurations at C6 and C12a were also prepared. The bioassay results indicated that most of these new compounds displayed moderate to good antiviral activity, among which compounds 23, 25, 27, 28, 31, and 5d showed a significantly higher activity than that of commercial ribavirin. An in-depth structure-activity relationship investigation showed that the spatial conformation was one of the most important factors in adjusting antiviral activity; the research results provided information about the possible optimum configuration for interaction of this molecular with its target protein. At the same time, these new compounds also exhibited broad-spectrum fungicidal activities against 14 kinds of phytopathogenic fungi. What's more, some of these compounds exhibited good insecticidal activity to Plutella xylostella and Culex pipiens pallens.

8.
Phys Rev Lett ; 124(13): 130603, 2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32302160

RESUMO

The non-Abelian topological phase with Fibonacci anyons minimally supports universal quantum computation. In order to investigate the possible phase transitions out of the Fibonacci topological phase, we propose a generic quantum-net wave function with two tuning parameters dual with each other, and the norm of the wave function can be exactly mapped into a partition function of the two-coupled ϕ^{2}-state Potts models, where ϕ=(sqrt[5]+1)/2 is the golden ratio. By developing the tensor network representation of this wave function on a square lattice, we can accurately calculate the full phase diagram with the numerical methods of tensor networks. More importantly, it is found that the non-Abelian Fibonacci topological phase is enclosed by three distinct nontopological phases and their dual phases of a single ϕ^{2}-state Potts model: the gapped dilute net phase, critical dense net phase, and spontaneous translation symmetry breaking gapped phase. We also determine the critical properties of the phase transitions among the Fibonacci topological phase and those nontopological phases.

9.
Chin J Integr Med ; 2020 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-32318906

RESUMO

Alzheimer's disease (AD) is the main type of dementia affecting elderly people. The medicines used for treating AD have limits in their ability to alleviate cognitive and functional decline. Electroacupuncture (EA), an economical alternative and complementary therapeutic measure used in Chinese medicine, has strong clinical applicability, and its treatment effects are more reliable as its stimulation factors can be standardized. EA has been effectively used for ameliorating spatial learning and memory impairment in AD patients and rodent AD models. Here, we summarized the mechanisms of EA on rodent AD models, aiming to provide a theoretical basis for identifying new targets and research directions, and exploring appropriate EA stimulation parameters, then provide a detailed methodology to optimize the effects of EA, ultimately reducing the heavy burden of treating AD patients on families and countries. Our review showed that 8 acupoints were used when treating AD animals; Baihui (GV 20) was the most frequently used. Four mechanisms of EA were studied: (1) protection of cerebral neurons from oxidative stress, apoptosis, neuroinflammation, synaptic plasticity and hormone levels; (2) regulation of metabolism, including glucose metabolism and plasma metabolism; (3) regulation of brain-derived neurotrophic factor; and (4) regulation of ß-amyloid peptide protein deposition.

10.
J Comput Biol ; 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-32298599

RESUMO

Clustered regularly interspaced short palindromic repeats (CRISPR), a class of immune-associated sequences in bacteria, have been developed as a powerful tool for editing eukaryotic genomes in diverse cells and organisms in recent years. The CRISPR-Cas9 system can recognize upstream 20 nucleotides (guide sequence) adjacent to the protospacer-adjacent motif site and trigger double-stranded DNA cleavage as well as DNA repair mechanisms, which eventually result in knockout, knockin, or site-specific mutagenesis. However, off-target effect caused by guide sequence misrecognition is the major drawback and restricts its widespread application. In this study, global analysis of specificities of all guide sequences in Arabidopsis thaliana, Oryza sativa (rice), and Glycine max (soybean) were performed. As a result, a simple pipeline and three genome-wide databases were established and shared for the scientific society. For each target site of CRISPR-Cas9, specificity score and off-target number were calculated and evaluated. The mean values of off-target numbers for A. thaliana, rice, and soybean were determined as 27.5, 57.3, and 174.7, respectively. Comparative analysis among these plants suggested that the frequency of off-target effects was correlated to genome size, chromosomal locus, gene density, and guanine-cytosine (GC) content. Our results contributed to the better understanding of CRISPR-Cas9 system in plants and would help to minimize the off-target effect during its applications in the future.

11.
Food Chem ; 320: 126634, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32208182

RESUMO

A multiplex pyrosequencing quantitative detection technique combined with universal primer-multiplex-PCR (UP-M-PCR) was established. In this study, a pyrosequencing results analysis software was first self-compiled, which realized the DNA sequences degeneration, and converted the pyrosequencing results and base composition of the target sequences into mathematic relations. Five calculation models were put forward based on the actual situation, which adjusted the values smaller than zero or the detection limit. By applying this method, samples containing five genetically modified (GM) lines mixed in random ratio were quantified, it showed that the quantification was very close to the actual value, and the detection sensitivity was as low as 1.47% of a single component, which satisfied most labeling policies. This novel method is realized without fluorescent group labeling, hence the number of targets is not limited by factors inherent in method or equipment, and is proven to be a reliable tool for the quantitative detection.

12.
J Org Chem ; 85(8): 5379-5389, 2020 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-32200642

RESUMO

Herein, we describe a new protocol for photoinduced radical [2+2+1] carbocyclization reactions of 1,7-enynes with bromofluoroacetate. These reactions, which proceed via a cascade involving fluoroalkylation, 6-exo-dig and 5-endo-trig cyclizations, H-transfer step, and oxidative dehydrogenation, provide an efficient and general route to a variety of fused monofluorinated cyclopenta[c]quinolin-4-one derivatives.

13.
Mikrochim Acta ; 187(4): 206, 2020 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-32152753

RESUMO

This review (with 126 references) summarizes the progress that has been made in the use of carbon nanotubes (CNTs) in immunoassays and immunosensors. Following an introduction into the field, a first large section covers functional group-modified CNTs as carriers for antibodies (with subsections on CNTs modified with amino, carboxy and by various other materials). The next section treats CNTs coupled with inorganic or organic materials as active components (with the use of nanoparticles such as Fe3O4, ZnO, gold) or with indium tin oxide (ITO), NiCoBP, ionic liquids, TiO2 nanosheets, metal clusters; chitosan, polystyrene, polydopamine, graphene, or enzymes. Another section discusses the synergistic effects of CNTs with metals, metal ions, and organic/inorganic materials. Several Tables are presented that give an overview on the wealth of methods and materials. A concluding section summarizes the current status, addresses current challenges, and gives an outlook on potential future trends. Graphical abstract Schematic presentation of the roles of carbon nanotubes (CNTs) in immunosensors and immunoassays. (I) Functional group-modified CNTs as carriers for antibody; (II) CNTs coupled with metal or organic materials as active component; and (III) Synergistic effects of CNTs with other materials to improve the parameters of immunosensors.

14.
Food Chem ; 316: 126303, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32045813

RESUMO

As the accumulation of mercury ions has a detrimental impact on human health, the design and development of a new type of biosensor that can rapidly, sensitively and selectively detect Hg2+ in aqueous solutions are essential. In this study, we have developed an exonuclease III (ExoIII) and Terminal deoxynucleotidyl transferase (TdT) dependent isothermal amplification (ETDA) colorimetric biosensor. The template sequence is a hairpin where -NH2 is labeled at the 3'-end and both termini are T-rich sequences. In the presence of Hg2+, the template formed a blunt end, and the catalytic activity of ExoIII was activated with cleavage of the -NH2 at the 3'-end. TdT enzyme activity was initiated with the formation of a large number of G-rich nucleic acid sequences. G-rich sequences incubated with iron (III)-hemin mimicked peroxidase-like activity, catalyzing the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2. The biosensor constructed in this paper had a good linear range, 1-25 nmol/L. Its detection limit was 0.41 nmol/L (3σ), and recovery rates were between 100.5% and 103%. In conclusion, combined with the colorimetric biosensor and double enzyme cyclic amplification reaction, an ultra-sensitivity and strong specificity detection method was developed to detect Hg2+. At the same time, this method also expands the detection method of Hg2+ available in the literature.

15.
Cells ; 9(1)2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31947603

RESUMO

Brown adipose tissue (BAT) plays an essential role in maintaining body temperature and in treating obesity and diabetes. The adult BAT (aBAT) and neonatal BAT (neBAT) vary greatly in capacity, but the characteristics and differences between them on the molecular level, as well as the related features of BAT as it develops post-delivery, have not yet been fully determined. In this study, we examined the morphological features of aBAT and neBAT of mice by using hematoxylin-eosin (H&E) staining, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). We found that neBAT contains a smaller number and size of lipid droplets, as well as more abundant mitochondria, compared with aBAT. The dynamic morphological changes revealed that the number and size of lipid droplets increase, but the number of mitochondria gradually decrease during the post-delivery development, which consisted of some differences in RNA or protein expression levels, such as gradually decreased uncoupling protein 1 (UCP1) expression levels and mitochondrial genes, such as mitochondrial transcription factor A (Tfam). The adipocyte differentiation-related genes, such as transcription factor CCAAT enhancer-binding protein ß (CEBPß), were also continuously upregulated. Additionally, the different features of aBAT and neBAT were analyzed from the global transcription (RNA-Seq) level, which included messenger RNA (mRNA), microRNA, long non-coding RNA (lncRNA), circRNA, and DNA methylation, as well as proteins (proteomics). Differentially methylated region (DMR) analysis identified 383 hyper- and 503 hypo-methylated genes, as well as 1221 new circRNA in ne-BAT and 1991 new circRNA in a-BAT, with significantly higher expression of circRNA in aBAT compared with neBAT. Gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that mitochondrial activity, protein synthesis, and cell life activity levels were higher in neBAT, and pathways related to ribosomes, spliceosomes, and metabolism were significantly activated in neBAT compared to aBAT. Collectively, this study describes the dynamic changes occurring throughout post-delivery development from the morphological, molecular and omics perspectives. Our study provides information that may be utilized in improving BAT functional activity through gene regulation and/or epigenetic regulation.

16.
Epigenetics ; 15(1-2): 199-214, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31314649

RESUMO

Precision toxicology evaluates the toxicity of certain substances by isolating a small group of cells with a typical phenotype of interest followed by a single cell sequencing-based analysis. In this in vitro attempt, ochratoxin A (OTA), a typical mycotoxin and food contaminant, is found to induce G0/G1 phase cell cycle arrest in human renal proximal tubular HKC cells at a concentration of 20 µM after a 24h-treatment. A small number of G0/G1 phase HKC cells are evaluated in both the presence and absence of OTA. These cells are sorted with a flow cytometer and subjected to mRNA and DNA methylation sequencing using Smart-Seq2 and single-cell reduced-representation bisulfite sequencing (scRRBS) technology, respectively. Integrated analysis of the transcriptome and methylome profiles reveals that OTA causes abnormal expression of the essential genes that regulate G1/S phase transition, act as signal transductors in G1 DNA damage checkpoints, and associate with the anaphase-promoting complex/cyclosome. The alteration of their DNA methylation status is a significant underlying epigenetic mechanism. Furthermore, Notch signaling and Ras/MAPK/CREB pathways are found to be suppressed by OTA. This attempt at precision toxicology paves the way for a deeper understanding of OTA toxicity and provides an innovative strategy to researchers in the toxicology and pharmacology field.

17.
Biosens Bioelectron ; 150: 111899, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31767350

RESUMO

Mercury pollutants such as mercuric chloride (HgCl2), mercurous chloride (Hg2Cl2) and mercuric ammonium chloride (Hg(NH2)Cl) are often found in cosmetics. Previous attempts at the on-site detection of mercury were hindered by the complicated and dangerous pretreatment procedure of converting various forms of mercury to Hg (II) ions. In this study, a test strip platform was developed based on a whole-cell microbial biosensor for the simultaneous detection of soluble and insoluble inorganic mercury pollutants in cosmetics without the need for predigestion. The genetic circuits with constitutively expressed MerR as sensor proteins and inducible red fluorescent protein (RFP) as the reporter were introduced into Escherichia coli to construct the mercury detection biosensor. The RFP fluorescence intensity of this biosensor showed a excellent linear relationship (R2 = 0.9848) with the Hg (II) concentration ranging from 50 nM to 10 µM in Luria-Bertani (LB) broth. Further research indicated that this biosensor could respond not only to Hg (II) ions but also to insoluble Hg2Cl2 and Hg2Cl2. The transcriptomic results confirmed the mercury conversion ability of the whole-cell biosensor from a gene expression perspective. This biosensor was embedded on filter paper to form a test strip, which could be used to determine whether the total inorganic mercury pollutants in cosmetics exceeded 1 mg/kg. Therefore, this strip provided a low cost, easy-to-use, and instrument-independent method for the detection of mercury pollution in cosmetics, while this study revealed the unique advantages of microbial biosensors in the automatic bioconversion of targets.

18.
J Agric Food Chem ; 68(2): 686-696, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31877248

RESUMO

Metabolites of serum and milk from genetically modified (GM) cows and contrast check (CK) cows were comparatively investigated. Serum and milk were collected from genetically modified (GM) cows and contrast check (CK) cows, and then, they were analyzed using ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) and gas chromatography-mass spectrometry (GC-MS). Although the level of some blood biochemical indexes for GM cows was shifted up or down, they were generally in normal physiological condition. Serum samples from lactoferrin GM cows exhibited reduced levels of amino acids and elevated levels of indoleacetate, α-keto acids, long-chain fatty acids, etc. GM milk possessed elevated levels of pentose and amino sugar metabolites, including arabitol, xylulose, glucuronate, and N-acetylgalactosamine. Interestingly, some essential nutrients, such as certain unsaturated fatty acids (e.g., eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and docosapentaenoic acid (DPA)), and some necessary rare sugars were significantly upregulated. Compared to the CK group, a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was conducted based on the increased or decreased metabolites identified in the serum and milk samples of the GM group. The results showed that the GM cows were in healthy condition and their milk has improved benefits for customers. The milk from genetically modified cows was found to be a promising milk source for producing recombinant human lactoferrin (rhLF) for human beings.


Assuntos
Animais Geneticamente Modificados/metabolismo , Lactoferrina/genética , Leite/química , Soro/química , Animais , Animais Geneticamente Modificados/genética , Bovinos/genética , Bovinos/metabolismo , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Feminino , Ácidos Indolacéticos/sangue , Cetoácidos/sangue , Lactoferrina/metabolismo , Metabolômica , Leite/metabolismo , Soro/metabolismo , Açúcares/sangue
19.
Food Chem ; 310: 125955, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31841941

RESUMO

Vibrio parahaemolyticus is a major hidden danger of food safety. To develop a rapid, sensitive and on-site detecting method of Vibrio parahaemolyticus (V. parahaemolyticus), a strand replacement primer thermostat phosphate (SRPP) visual sensor was proposed, based on Bst DNA polymerase and pyrophosphatase. The novel strand replacement primer (SRP) facilitates chain substitution and to open a self-folding hairpin by adding region at its 3' end. Under the action of the SRP, a pair of external primers and two inner primers, target DNA is specifically amplified at 63 °C relies mainly on the hairpin. Many pyrophosphates (PPi) are simultaneously generated as by-products, which can be converted into phosphates (Pi) by pyrophosphatase for phosphomolybdate blue visual detection within 5 min. The proposed biosensor can detect 1.29 × 103 copies of V. parahaemolyticus within 35 min.


Assuntos
Primers do DNA/genética , Análise de Alimentos/instrumentação , Microbiologia de Alimentos/métodos , Vibrio parahaemolyticus/genética , DNA Polimerase Dirigida por DNA/genética , Análise de Alimentos/métodos , Pirofosfatases/genética , Sensibilidade e Especificidade
20.
Food Chem ; 302: 125359, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442702

RESUMO

A simple and rapid sensing strategy was proposed for chloramphenicol (CAP) detection based on structure-switching signaling aptamers. In this protocol, the aptamer can bind to both the fluorophore (FAM)-labeled complementary strand and the quencher (BHQ1)-labeled complementary strand, thus leading to the effective quenching of FAM fluorescence by BHQ1. However, when CAP is present, the structure switch is reversed because the aptamer recognizes CAP, resulting in fluorescence recovery. Such a fluorescence-sensing platform can monitor CAP within a good linear range (1-100 ng/mL), with a detection limit of 0.70 ng/mL. Cross-reactivity with other common antibiotics is negligible, indicating the excellent selectivity of the strategy. Moreover, as the aptamers are not modified, this method is simple and low-cost. The present work reveals a new direction for detecting CAP or other target compounds without prior knowledge of the secondary or tertiary structures of the aptamer.


Assuntos
Aptâmeros de Nucleotídeos/química , Cloranfenicol/análise , Transferência Ressonante de Energia de Fluorescência/métodos , Análise de Alimentos/métodos , Animais , Antibacterianos/análise , Aptâmeros de Nucleotídeos/metabolismo , Corantes Fluorescentes/química , Contaminação de Alimentos/análise , Limite de Detecção , Leite/química , Sensibilidade e Especificidade
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