Prognostic Signature Constructed of Seven Ferroptosis-Related lncRNAs Predicts the Prognosis of HBV-Related HCC.

BACKGROUND: Ferroptosis and lncRNAs both play crucial roles in cancers. But the roles of ferroptosis-related lncRNAs (FRLncs) in HBV-related HCC (HBV-HCC) remain ambiguous. METHODS: The gene expression profile and clinical data were originated from the Cancer Genome Atlas (TCGA) database. The risk signature was constructed by FRLncs based on the Cox regression analysis. The survival curve, Cox regression analysis, and time-dependent receiver operating characteristic (ROC) curve were adopted to verify the independence and reliability of the signature. A nomogram was established. Immune-infiltrating cells, immune functions, and checkpoints were analyzed. RESULTS: A risk signature composed of 7 FRLncs (LINC00942, AC131009.1, POLH-AS1, AC090772.3, MKLN1-AS, AC009403.1, AL031985.3) was constructed and divided HBV-HCC patients into high- and low-risk groups. Patients in the high-risk group showed a poor prognosis. The area under curves (AUC) of the signature for 1-, 3-, and 5-year was satisfactory. A nomogram composed of gender, stage, age, grade, and risk signature was established. The risk signature and nomogram displayed appreciable independence and reliability in HBV-HCC patients. The T-cell CD8 + , monocyte, and macrophage M1 were expressed differently significantly in HCC patients, while macrophage M2 showed an obvious difference in the HBV-HCC patients between the different risk groups. PDCD1 and CTL4 were expressed higher in the high-risk group of HCC patients. CONCLUSION: A 7-lncRNA signature was identified as a potential prognostic predictor for HBV-HCC patients. Immune therapy may be a promising strategy for HCC patients, especially HBV-HCC patients.

Platinum Nanoparticles Loaded Graphitic Carbon Nitride Nanosheets with Enhanced Peroxidase-like Activity for H2O2 and Oxidase-Based Sensing.

Platinum nanoparticles (PtNPs) are classical peroxidase-like nanozyme; self-agglomeration of nanoparticles leads to the undesirable reduction in stability and catalytic activity. Herein, a hybrid peroxidase-like nanocatalyst consisting of PtNPs in situ growing on g-C3N4 nanosheets with enhanced peroxidase-mimic catalytic activity (PtNP@g-C3N4 nanosheets) was prepared for H2O2 and oxidase-based colorimetric assay. g-C3N4 nanosheets can be used as carriers to solve the problem of poor stability of PtNPs. We observed that the catalytic ability could be maintained for more than 90 days. PtNP@g-C3N4 nanosheets could quickly catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), and the absorbance of blue color oxidized TMB (oxTMB) showed a robust linear relationship with the concentration of H2O2 (the detection limit (LOD): 3.33 µM). By utilizing H2O2 as a mediator, this strategy can be applied to oxidase-based biomolecules (glucose, organophosphorus, and so on, that generate or consume hydrogen peroxide) sensing. As a proof of concept, a sensitive assay of cholesterol that combined PtNP@g-C3N4 nanosheets with cholesterol oxidase (ChOx) cascade catalytic reaction was constructed with an LOD of 9.35 µM in a widespread range from 10 to 800 µM (R2 = 0.9981). In addition, we also verified its ability to detect cholesterol in fetal bovine serum. These results showed application prospect of PtNP@g-C3N4 nanosheets-based colorimetry in sensing and clinical medical detection.

ß-Cyclodextrin Polymer-Based Fluorescence Enhancement Strategy via Host-Guest Interaction for Sensitive Assay of SARS-CoV-2.

Nucleocapsid protein (N protein) is an appropriate target for early determination of viral antigen-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We have found that ß-cyclodextrin polymer (ß-CDP) has shown a significant fluorescence enhancement effect for fluorophore pyrene via host-guest interaction. Herein, we developed a sensitive and selective N protein-sensing method that combined the host-guest interaction fluorescence enhancement strategy with high recognition of aptamer. The DNA aptamer of N protein modified with pyrene at its 3' terminal was designed as the sensing probe. The added exonuclease I (Exo I) could digest the probe, and the obtained free pyrene as a guest could easily enter into the hydrophobic cavity of host ß-CDP, thus inducing outstanding luminescent enhancement. While in the presence of N protein, the probe could combine with it to form a complex owing to the high affinity between the aptamer and the target, which prevented the digestion of Exo I. The steric hindrance of the complex prevented pyrene from entering the cavity of ß-CDP, resulting in a tiny fluorescence change. N protein has been selectively analyzed with a low detection limit (11.27 nM) through the detection of the fluorescence intensity. Moreover, the sensing of spiked N protein from human serum and throat swabs samples of three volunteers has been achieved. These results indicated that our proposed method has broad application prospects for early diagnosis of coronavirus disease 2019.

Control of lateral root initiation by DA3 in Arabidopsis.

Lateral root (LR) initiation is controlled by the pericycle and the neighboring endodermis in Arabidopsis. Here, we demonstrate that UBIQUITIN-SPECIFIC PROTEASE14/DA3 regulates LR initiation by modulating auxin signaling in the pericycle and endodermis. DA3 negatively affects the mRNA and protein levels of AUXIN RESPONSE FACTOR7 (ARF7) and ARF19 in the pericycle and endodermis but positively regulates the protein stability of SHORT HYPOCOTYL 2 (SHY2/IAA3), an auxin signaling repressor, in the endodermis. We show that DA3 interacts with ARF7 and ARF19, inhibiting their binding to the locus of LATERAL ORGAN BOUNDARY DOMAIN16 (LBD16) to repress its expression in the pericycle. SHY2 also interacts with ARF7 and ARF19 in the endodermis and enhances the DA3 repressive effect on ARF7 and ARF19, thus modulating LBD16 expression in the pericycle. Overall, our findings show that DA3 acts with SHY2, ARF7, and ARF19 to coordinate auxin signaling in the pericycle and endodermis to control LR initiation in Arabidopsis.

Aptamer-Gated Mesoporous Silica Nanoparticles for N Protein Triggered Release of Remdesivir and Treatment of Novel Coronavirus (2019-nCoV).

Since the 2019-nCoV outbreak was first reported, hundreds of millions of people all over the world have been infected. There is no doubt that improving the cure rate of 2019-nCoV is one of the most effective means to deal with the current serious epidemic. At present, Remdesivir (RDV) has been clinically proven to be effective in the treatment of SARS-CoV-2. However, the uncertain side effects make it important to reduce the use of drugs while ensuring the self-healing effect. We report an approach here with targeted therapy for the treatment of SARS-CoV-2 and other coronaviruses illness. In this study, mesoporous silica was used as the carrier of RDV, the nucleocapsid protein (N protein) aptamer was hybridized with the complementary chain, and the double-stranded DNA was combined with gold nanoparticles as the gates of mesoporous silica pores. When the RDV-loaded mesoporous silica is incubated with the N protein, aptamer with gold nanoparticles dissociate from the complementary DNA oligonucleotide on the mesoporous silica surface and bind to the N protein. The releasing of RDV was determined by detecting the UV-vis absorption peak of RDV in the solution. These results show that the RDV delivery system designed in this work has potential clinical application for the treatment of 2019-nCoV.

An electrochemical aptasensor with N protein binding aptamer-complementary oligonucleotide as probe for ultra-sensitive detection of COVID-19.

The emergence of the COVID-19 epidemic has affected the lives of hundreds of millions of people globally. There is no doubt that the development of fast and sensitive detection methods is crucial while the worldwide effective vaccination programs are miles away from actualization. In this study, we have reported an electrochemical N protein aptamer sensor with complementary oligonucleotide as probe for the specific detection of COVID-19. The electrochemical aptasensor was prepared by fixing the double-stranded DNA hybrid obtained by the hybridization of N protein aptamer and its Fc-labeled complementary strand on the surface of a gold electrode. After incubation with the target, the aptamer dissociated from the labeled complementary DNA oligonucleotide hybrid to preferentially bind with N protein in the solution. The concentration of N protein was measured by detecting the changes in electrochemical current signals induced by the conformational transformation of the complementary DNA oligonucleotide left on the electrode surface. The sensor had a linear relationship between the logarithm of the N protein concentration from 10 fM to 100 nM (ΔIp = 0.098 log CN protein/fM - 0.08433, R2 = 0.99), and the detection limitation was 1 fM (S/N = 3). The electrochemical aptamer sensor was applied to test the spiked concentrations of throat swabs and blood samples from three volunteers, and the obtained results proved that the sensor has great potentials for the early detection of COVID-19 in patients.

Effects of tryptophan and phenylalanine on tryptophol production in Saccharomyces cerevisiae revealed by transcriptomic and metabolomic analyses.

Tryptophol (TOL) is a metabolic derivative of tryptophan (Trp) and shows pleiotropic effects in humans, plants and microbes. In this study, the effect of Trp and phenylalanine (Phe) on TOL production in Saccharomyces cerevisiae was determined, and a systematic interpretation of TOL accumulation was offered by transcriptomic and metabolomic analyses. Trp significantly promoted TOL production, but the output plateaued (231.02-266.31 mg/L) at Trp concentrations ≥ 0.6 g/L. In contrast, Phe reduced the stimulatory effect of Trp, which was strongly dependent on the Phe concentration. An integrated genomic, transcriptomic, and metabolomic analysis revealed that the effect of Trp and Phe on TOL production was mainly related to the transamination and decarboxylation of the Ehrlich pathway. Additionally, other genes, including thiamine regulon genes (this), the allantoin catabolic genes dal1, dal2, dal4, and the transcriptional activator gene aro80, may play important roles. These findings were partly supported by the fact that the thi4 gene was involved in TOL production, as shown by heterologous expression analysis. To the best of our knowledge, this novel biological function of thi4 in S. cerevisiae is reported here for the first time. Overall, our findings provide insights into the mechanism of TOL production, which will contribute to TOL production using metabolic engineering strategies.

ß-Cyclodextrin Polymer-Based Host-Guest Interaction and Fluorescence Enhancement of Pyrene for Sensitive Isocarbophos Detection.

The extensive use of organophosphorus pesticides in agriculture poses a high risk to human health and has boosted the demands for developing sensitive monitoring methods. Herein, we developed a facile and sensitive method for isocarbophos detection based on the remarkable fluorescence enhancement of pyrene during host-guest interaction of ß-cyclodextrin polymer (ß-CDP) and pyrene. The 3'-pyrene-labeled isocarbophos aptamer could be cleaved by exonuclease I to obtain free pyrene that was tagged on mononucleotides, which could enter the hydrophobic cavity of ß-CDP, resulting in a prominent fluorescence enhancement. While the target isocarbophos was added, aptamer could undergo a conformational change into a hairpin complex, which prevented the cleavage and host-guest interaction because of the steric hindrance, leading to a weak fluorescence. The isocarbophos has been sensitively and selectively analyzed by detecting the system fluorescence intensity with a detection limit as low as 1.2 µg/L. In addition, we have verified the ability of our proposed method in real sample detection from fruit extract.

Release of florfenicol in seawater using chitosan-based molecularly imprinted microspheres as drug carriers.

Novel molecularly imprinted polymer (MIP) microspheres using functionalized chitosan as eco-friendly substrates were prepared by surface imprinting method and applied as drug delivery carriers to provide extended-release of florfenicol (FF) in seawater. The chitosan-based composites were characterized by scanning electron microscopy and Fourier transforms infrared spectroscopy analyses. The swelling behavior, adsorption capability, and selectivity for FF were investigated. The results show that the MIPs possessed high drug loading saturation capacity and specific recognition affinity for FF. The release studies of MIPs as drug delivery carriers were evaluated in natural seawater. The microspheres exhibited slow sustained release profiles of FF and the release behavior conformed to the first-order kinetic equation. The imprinted microspheres as drug delivery devices would be a promising application for improving the efficacy of the antibiotic without exposing the ecological system to excess FF in aquaculture.

Functional role of miR­155 in physiological and pathological processes of liver injury (Review).

There are several types of liver injury, including alcohol­induced liver injury, drug­induced liver injury, infectious liver injury, cirrhosis, liver ischemia/reperfusion injury and liver failure. In recent years, accumulated data have demonstrated that microRNAs (miRNAs/miRs) may be involved in the occurrence and development of a variety of systemic diseases, such as immune diseases, tumors and nervous system diseases. miR­155 is a key miRNA, which has been studied extensively and has been shown to target different genes. In the present review, the potential effects and mechanisms of miR­155 on the physiological and pathological processes of liver injury were reviewed from the perspective of cell stress, inflammation and activation of fibrosis. In addition, the potential benefits of miR­155 as a therapeutic target and predictor of liver injury were summarized.

[Influence on orbicularis oculi muscle in the patients with facial neuritis treated with the penetra-ting needling at Cuanzhu (BL2) and Yuyao (EX-HN4) combined with the perpendicular needling at Shenmai (BL62)].

OBJECTIVE: To explore the therapeutic effect on incomplete eyelid in the patients with facial neuritis treated with the penetrating needling at Cuanzhu (BL2) and Yuyao (EX-HN4) combined with the perpendicular needling at Shenmai (BL62). METHODS: A total of 64 patients with facial neuritis, in compliance with the inclusion criteria, were randomized into a treatment group and a control group, with 32 cases in each. In the treatment group, the penetrating needling was applied to BL2 and EX-HN4 on the affected side, combined with the perpendicular needling at bilateral BL62. Besides, on the affected side, the penetrating needling was applied from Yangbai (GB14) toward four directions, named Shangxing (GV23), Touwei (ST8), Cuanzu (BL2) and Sizukong (TE23), the mutual penetrating needling was adopted between Dicang (ST4) and Jiache (ST6). Between Yingxiang (LI20) and Xiaguan (ST7), a row-arranged needling technique was applied. All of the needles were retained for 10 to 30 min in each treatment. The treatment was given once daily and the treatment for 10 days was as 1 course. A total of 2 courses of treatment were required. In the control group, prednisone acetate （30 mg/d）, was administered consecutively for 5 days. Afterward, the dose was reduced to be 10 mg/d and the medication stopped after taking consecutively for 1 week. Muscular injection with vitamin B12 （0.5 mg） and B1 （0.1 mg） was given, once daily. 10 days later, vitamin B1 was taken for oral administration, 10 mg each time, three times a day, for 10 days totally. Before and after the treatment, the clinical effect was compared between the two groups in terms of the analysis on the Hourse-Brackman (H-B) grade of facial nerve function, the distance between the upper and the lower eyelids, muscle strength, degree of eyelid closure and electromyogram (EMG). RESULTS: The total effective rate of treatment group was 96.9 % (31/32), better than 84.4%（27/32） in the control group (P<0.05). After treatment, in the treatment group, the distance between the upper and lower eyelids, the muscle strength, the degree of eyelid closure, the wave amplitude of motor nerve conduction and the latent period, as well as the blink reflex were all improved as compared with those before the treatment (P<0.01, P<0.05). In the control group, the distance between the upper and lower eyelids, the muscle strength, the degree of eyelid closure, the latent period of motor nerve conduction and the blink reflex were all improved as compared with those before the treatment (P<0.01, P<0.05). After the treatment, the results of the distance between the upper and lower eyelids, the muscle strength, the degree of eyelid closure, the wave amplitude of motor nerve conduction and the latent period, as well as the blink reflex in the treatment group were all better than those in the control group (P<0.05，P<0.01). CONCLUSION: The treatment with the penetrating needling at Cuanzhu (BL2) and Yuyao (EX-HN4) combined with the perpendicular needling at Shenmai (BL62) greatly promotes the recovery of orbicularis oculi muscle in the patients with facial neuritis, reduces the complications and presents the satisfactory clinical effect.

[Jingjin needling improves facial nerve function and psychosomatic function in Hunt facial para-lysis patients].

OBJECTIVE: To observe the clinical effectiveness of Jingjin (muscle region) needling in the treatment of Hunt facial paralysis (HFP). METHODS: A total of 80 HFP patients were randomly divided into acupuncture and medication groups (n＝40 cases/group). Jingjin needling was applied to Yangbai(GB14) to Shangxing (GV23), Touwei (ST8), Cuanzhu (BL2), Sizhukong (TE23，penetrative needling), Dicang (ST4) to Jiache (ST6, penetrative needling), Yingxiang(LI20) and Xiaguan(ST7), Hegu(LI4), Yifeng (TE17), Yuyao (EX-HN 4), and Shenmai (BL62), with the needles retained for 30 min. The treatment was conducted once daily, with 10 consecutive days being a therapeutic course, and 3 courses altogether. Patients of the medication group received oral administration of Prednisone acetate (12 days), Acyclovir (7 days), intramuscular injection of Vitamin B12 and Vitamin B1(10 days), then, oral administration of Vitamin B1, successively. The therapeutic effect was assessed by using House-Brackman (H-B) facial function grading system (grade I to VI), traditional Chinese medicine (TCM) sign and symptom score, and facial disability index (FDI) scale including FDI physical function (FDIP, food and water swallowing, speaking-pronouncing, dryness or tearing, and mouth-opening) and FDI social function (FDIS, self-rating anxiety/depression scales), separately. RESULTS: After the treatment, the TCM symptom and sign scores for depth of nasolabial groove, nose shrugging, lower lip asymmetry, food retention and post-auricular pain were significantly lower in the medication group (P<0.05)．After the treatment, the TCM symptom and sign scores for frontal muscle movement, eyelid opening and closing, depth of nasolabial groove, nose shrugging, lower lip asymmetry, cheek blowing, food retention, latissimus cervicalis contraction, taste disorder, hearing hypersensitivity, tears and discomfort and post-auricular pain were significantly lower in the acupuncture group (P<0.05)．Comparison between two groups showed that the TCM symptom and sign scores for frontal muscle movement, eyelid opening and closing, depth of nasolabial groove, nose shrugging, lower lip asymmetry, cheek blowing, food retention, latissimus cervicalis contraction, taste disorder, hearing hypersensitivity, tears and discomfort and post-auricular pain were significantly lower in the acupuncture group than in the medication group(P<0.05)．The scores of FDIP and FDIS were significantly increased in both groups (P<0.01) and notably higher in the acupuncture group than in the medication group (P<0.01) after the treatment. The total effective rate of acupuncture group was 97.5% (39/40), and that of medication group was 72.5% (29/40). The therapeutic effect of the acupuncture group was significantly superior to that of the medication group (P<0.01)．. CONCLUSION: Jingjin needling has a good therapeutic effect in improving facial nerve function, psychosomatic function and clinical signs and symptoms in HFP patients, evidently being better than medication.

Photodriven Regeneration of G-Quadruplex Aptasensor for Sensitively Detecting Thrombin.

Aptamers have been widely used as recognition elements in electrochemical sensors. However, as the most expensive consumable, the aptasensors regeneration is still a critical challenge for sustainable feasibility and attracting great interest from researchers, due to the high affinity between the aptamers and their targets (the dissociation constant Kd is low to subnanomolar or nanomolar). In this work, we propose a photochromic five-azobenzene-inserted thrombin-aptamer based aptasensor to improve the regenerativity. With ultraviolet light exposure, the trans-structure of azobenzene changes to cis-structure, and open the folded aptamer to realize the aptasensor regeneration. The limit of detection can be sensitive to 3 pM (S/N = 3). The thrombin concentrations were detected to be 2.48 ± 0.02 and 20.26 ± 0.98 nM (n = 3) in duck whole blood and blood serum, respectively. Utilizing surface plasmon resonance, we demonstrated that the certain azobenzene moieties can exactly increase Kd of aptamer-thrombin bounding. The photodriven conversion of thrombin-aptamer from G-quadruplex to loosen structure approaches a convenient regeneration for aptasensor, which will promote its popularization and sustainable feasibility.

Highly rapid and non-enzymatic detection of cholesterol based on carbon nitride quantum dots as fluorescent nanoprobes.

In this work, we reported a highly rapid and non-enzymatic method for cholesterol measuring based on carbon nitride quantum dots (CNQDs) as fluorescent nanoprobes, which were synthesized through chemical oxidation. The obtained CNQDs displayed high quantum yield up to 35% as well as excellent photostability, water solubility and low toxicity. We found that the fluorescence of CNQDs could be quenched more than 90% within 30 seconds by cholesterol through the formation of hydrogen bonds between -NH2, -NH on the surface of CNQDs and cholesterol containing -OH. According to this phenomenon, a cholesterol detection method was constructed with a wide linear region over the range of 0-500 µmol L-1 and a detection limit as low as 10.93 µmol L-1, and it possessed the obvious advantages of being a very rapid process and avoiding the use of enzymes. In addition, this method showed high selectivity in the presence of various interfering reagents and applicability to the measurement of cholesterol in fetal bovine serum, which indicated its potential application value in clinical settings.

DNA-Templated Fluorescent Nanoclusters for Metal Ions Detection.

DNA-templated fluorescent nanoclusters (NCs) have attracted increasing research interest on account of their prominent features, such as DNA sequence-dependent fluorescence, easy functionalization, wide availability, water solubility, and excellent biocompatibility. Coupling DNA templates with complementary DNA, aptamers, G-quadruplex, and so on has generated a large number of sensors. Additionally, the preparation and applications of DNA-templated fluorescent NCs in these sensing have been widely studied. This review firstly focuses on the properties of DNA-templated fluorescent NCs, and the synthesis of DNA-templated fluorescent NCs with different metals is then discussed. In the third part, we mainly introduce the applications of DNA-templated fluorescent NCs for sensing metal ions. At last, we further discuss the future perspectives of DNA-templated fluorescent NCs in the synthesis and sensing metal ions in the environmental and biological fields.

[Development and application of two-dimensional liquid chromatography for the analysis of polycyclic aromatic sulfur heterocycles in heavy oil].

A two-dimensional liquid chromatographic (2D LC) system was developed for the analysis of polycyclic aromatic sulfur heterocycles (PASHs) in heavy oil. The first dimension is a ligand-exchange chromatographic column packed with a palladium chloride/silica (PdCl2-SiO2) stationary phase, while the second dimension is a Spherisorb-NH2 column. The PASHs in vacuum gas oil were enriched online, and polycyclic aromatics hydrocarbons (PAHs) were separated according to their aromatic ring numbers. These separated fractions were analyzed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and detailed molecular characterization of PASHs and PAHs was achieved. Typical molecular structures of PASHs and PAHs in these fractions could be provided, and the side chain as well as the core structures were predicted. It is significant for the feedstocks selection and optimization of the hydrodesulfurization process by using these molecular characterization information.

Expansion of a Population of Large Monocytes (Atypical Monocytes) in Peripheral Blood of Patients with Acute Exacerbations of Chronic Obstructive Pulmonary Diseases.

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is closely associated with airway inflammation including monocytes, lymphocytes, and neutrophils. Monocytes play an essential role in the pathogenesis of chronic obstructive pulmonary disease (COPD). To elucidate the association of circulating monocyte alteration with AECOPD, we analyzed monocyte subpopulation in the peripheral blood of 16 healthy volunteers and 22 AECOPD patients at the stages of admission and remission after clinical therapy. We found a dramatic increase of a previously unreported population of large size circulating atypical monocytes (A Mo) in AECOPD patients, characterized by higher forward scatter and lower side scatter values than the typical monocytes (T Mo) which were observed predominantly in healthy individuals. Further analysis showed that A Mo expressed higher levels of CD16, intercellular adhesion molecule 1 (ICAM-1), and chemotactic protein-1 receptor-2 (CCR2) than T Mo. In contrast, the expression of class II antigen (HLA-DR) by A Mo was lower than T Mo. More importantly, we observed that the percentage of circulating A Mo among total monocytes correlated with the length of hospital stay (time to remission) and disease duration. The data suggest that circulating A Mo might have the potential to serve as a biomarker in the diagnosis and prognosis of AECOPD.

Label-free and sensitive detection of Ochratoxin A based on dsDNA-templated copper nanoparticles and exonuclease-catalyzed target recycling amplification.

Ochratoxin A (OTA) is one of the most toxic mycotoxins and exists in various food commodities. Herein, a sensitive fluorescence method was developed for OTA detection which combines the advantages of label-free dsDNA-templated copper nanoparticles (CuNPs), high selectivity of OTA aptamer and high efficiency of exonuclease-catalyzed target recycling amplification. OTA aptamer was hybridized with its complementary DNA (cDNA), and the obtained dsDNA acted as the template for fluorescent CuNPs. In the presence of its target (OTA), the aptamer prefers to form an OTA-aptamer complex in lieu of an aptamer-DNA duplex, which results in the dissociation of the aptamer-DNA duplex. The released cDNA and aptamer could be digested into mononucleotides by the RecJf exonuclease (single-stranded DNA specific exonuclease), and the target was liberated and could participate in the next reaction cycle. The above process resulted in the degradation of a large amount of template dsDNA, which prevented the synthesis of CuNPs, thus resulting in low fluorescence of the system. Based on this strategy, a label-free and sensitive detection of OTA was developed with a low detection limit of 5 ng mL-1 (S/N = 3). Our strategy was further validated and evaluated successfully by assaying OTA in real samples. The proposed assay has great potential as an OTA quantification method for use in the food safety field.

Photoinduced Regeneration of an Aptamer-Based Electrochemical Sensor for Sensitively Detecting Adenosine Triphosphate.

Electrochemical aptasensors generally include three elements, that is, recognition element, signal-transformation element, and regeneration element. In this study, a new adenosine triphosphate (ATP) aptasensor is developed by combining three elements into one DNA oligonucleotide chain. In the DNA oligonucleotide chain, DNA aptamer is used as the recognition element, ferrocene group attached at the 3'-end of the aptamer is used as the signal-transformation element, and azobenzene moiety embedded into the DNA chain is used as the regeneration element. In addition to the similar analytical properties with the traditional ones, the aptasensor developed here is easily regenerated with UV-light irradiation. The current response recorded on the aptasensor increases with increasing the concentration of ATP in the incubation solution and is linear with the logarithm of ATP concentration in the range from 1 nM to 100 µM. The limit of detection is 0.5 nM (S/N = 3). The basal level of ATP in the rat brain cortex microdialysate is determined to be 21.33 ± 4.1 nM ( n = 3). After being challenged with ATP, the aptasensor could be readily regenerated by UV-light irradiation for more than seven cycles. The regeneration of the aptasensor is proposed to be regulated by conversing azobenzene from its trans to cis form under UV irradiation.

Salinity-Induced Palmella Formation Mechanism in Halotolerant Algae Dunaliella salina Revealed by Quantitative Proteomics and Phosphoproteomics.

Palmella stage is critical for some unicellular algae to survive in extreme environments. The halotolerant algae Dunaliella salina is a good single-cell model for studying plant adaptation to high salinity. To investigate the molecular adaptation mechanism in salinity shock-induced palmella formation, we performed a comprehensive physiological, proteomics and phosphoproteomics study upon palmella formation of D. salina using dimethyl labeling and Ti4+-immobilized metal ion affinity chromatography (IMAC) proteomic approaches. We found that 151 salinity-responsive proteins and 35 salinity-responsive phosphoproteins were involved in multiple signaling and metabolic pathways upon palmella formation. Taken together with photosynthetic parameters and enzyme activity analyses, the patterns of protein accumulation and phosphorylation level exhibited the mechanisms upon palmella formation, including dynamics of cytoskeleton and cell membrane curvature, accumulation and transport of exopolysaccharides, photosynthesis and energy supplying (i.e., photosystem II stability and activity, cyclic electron transport, and C4 pathway), nuclear/chloroplastic gene expression regulation and protein processing, reactive oxygen species homeostasis, and salt signaling transduction. The salinity-responsive protein-protein interaction (PPI) networks implied that signaling and protein synthesis and fate are crucial for modulation of these processes. Importantly, the 3D structure of phosphoprotein clearly indicated that the phosphorylation sites of eight proteins were localized in the region of function domain.