Morphological and molecular characterization of Rhizoctonia solani AG-3 associated with tobacco target leaf spot in China.

Tobacco target leaf spot is a leaf disease that seriously affects both the quantity and quality of commercial tobacco crops and has caused huge economic losses in many countries and also pandemics in China since 2006. The anastomosis group-3 (AG-3) pathogen is divided into different subgroups namely AG-3 PT (potato type), AG-3TB (tobacco type), and AG-3 TM (tomato type), based on their host and the combined data from the ribosomal DNA internal transcribed spacer (rDNA-ITS), rDNA intergenic spacer 1 (rDNA-IGS1) regions, and translation elongation factor 1-α (tef-1α) gene. In this study, we collected tobacco leaves showing target spot symptom from four fields in China. We obtained 49 isolates from southwest China (Yunnan Provinces) and six isolates from northeast China (Liaoning Province). Phylogenetic tree based on rDNA-ITS region indicated that 51 isolates (49 isolates from Yunnan and two isolates from Liaoning) and 4 isolates from Liaoning belonged to AG-3 TB and AG-3 TM, respectively.

Embedding Proteins within Spatially Controlled Hierarchical Nanoarchitectures for Ultrasensitive Immunoassay.

Modulating the precise self-assembly of functional biomacromolecules is a critical challenge in biotechnology. Herein, functional biomacromolecule-assembled hierarchical hybrid nanoarchitectures in a spatially controlled fashion are synthesized, achieving the biorecognition behavior and signal amplification in the immunoassay simultaneously. Biomacromolecules with sequential assembly on the scaffold through the biomineralization process show significantly enhanced stability, bioactivity, and utilization efficiency, allowing tuning of their functions by modifying their size and composition. The hierarchically hybrid nanoarchitectures show great potential in construction of ultrasensitive immunoassay platforms, achieving a three order-of-magnitude increase in sensitivity. Notably, the well-designed HRP@Ab2 nanoarchitectures allow for optical immunoassays with a detection range from picogram mL-1 to microgram mL-1 on demand, providing great promise for quantitative analysis of both low-abundance and high-residue targets for biomedical applications.

Molecular characterization of a novel mitovirus from Rhizoctonia solani AG-4 HGIII strain XMC-IF.

The nucleotide sequence of a viral double-stranded RNA (dsRNA) from Rhizoctonia solani AG-4 HGIII strain XMC-IF (designated as "Rhizoctonia solani mitovirus 106", RsMV-106) was determined. The complete sequence was 2794 bp in length with a 57.50% A + U content and contained a large open reading frame (ORF) when the fungal mitochondrial genetic code was used. The ORF potentially encodes a 95.76-kDa protein containing a conserved domain of an RNA-dependent RNA polymerase (RdRp). BLASTp analysis revealed that the RdRp domain of RsMV-106 shared 47.52-73.24% sequence identity with those of viruses of the genus Duamitovirus and was most similar (73.24% identity) to that of Alternaria alternata mitovirus 1 (AaMV1). Phylogenetic analysis showed that RsMV-106 is a novel member of the genus Duamitovirus, family Mitoviridae. This is the first report of the full genome sequence of a mitovirus associated with R. solani AG-4 HGIII.

Facile Secondary Deposition for Improving Quantum Dot Loading in Fabricating Quantum Dot Solar Cells.

Sufficient loading of presynthesized quantum dots (QDs) on mesoporous TiO2 electrodes is the prerequisite for the fabrication of high-performance QD-sensitized solar cells (QDSCs). Here, we provide a general approach for increasing QD loading on mesoporous TiO2 films by surface engineering. It was found that the zeta potential of presensitized TiO2 can be effectively adjusted by surfactant treatment, on the basis of which additional QDs are successfully introduced onto photoanodes during secondary deposition. The strategy developed, that is, the secondary deposition incorporating surfactant treatment, makes it possible to load various QDs onto photoanodes regardless of the nature of QDs. In standard AM 1.5G sunlight, a certified efficiency of 10.26% for the QDSC with Cu2S/brass counter electrodes was achieved by the secondary deposition of Zn-Cu-In-Se QDs.

Screening and rational design of hepatitis C virus entry inhibitory peptides derived from GB virus A NS5A.

Chronic infection by hepatitis C virus (HCV) is a cause of the global burden of liver diseases. HCV entry into hepatocytes is a complicated and multistep process that represents a promising target for antiviral intervention. The recently reported amphipathic α-helical virucidal peptide (C5A) from the HCV NS5A protein suggests a new category of antiviral drug candidates. In this study, to identify C5A-like HCV inhibitors, synthetic peptides derived from the C5A-corresponding NS5 protein region of selected Flaviviridae viruses were evaluated for their anti-HCV activities. A peptide from GB virus A (GBV-A), but not other flaviviruses, demonstrated an inhibitory effect on HCV infection. Through a series of sequence optimizations and modifications of the peptide helicity and hydrophobicity, we obtained a peptide designated GBVA10-9 with highly potent anti-HCV activity. GBVA10-9 suppressed infection with both cell culture-derived and pseudotyped HCV in vitro, and the 50% cell culture inhibitory concentration ranged from 20 nM to 160 nM, depending on the genotypic origin of the envelope proteins. GBVA10-9 had no detectable effects on either HCV attachment to Huh7.5.1 cells or viral RNA replication. No virucidal activity was found with GBVA10-9, suggesting an action mechanism distinct from that of C5A. The inhibitory effect of GBVA10-9 appeared to occur at the postbinding step during viral entry. Taken together, the results with GBVA10-9 demonstrated a potent activity for blocking HCV entry that might be used in combination with other antivirals directly targeting virus-encoded enzymes. Furthermore, GBVA10-9 also provides a novel tool to dissect the detailed mechanisms of HCV entry.

Structure-guided RP-HPLC chromatography of diastereomeric α-helical peptide analogs substituted with single amino acid stereoisomers.

An α-helical model peptide (Ac-EAEKAAKE-X-EKAAKEAEK-amide) was used as a template to examine the efficacy of conventional reversed-phase high-performance liquid chromatography (RP-HPLC) in separating peptide analogs with single substitutions (at position X) of diasteromeric amino acids Ile, allo-Ile, d-Ile and d-allo-Ile. We compared differences in peptide retention behavior on a C8 column and a C18 column at different temperatures. We demonstrated how subtle differences in peptide secondary structure affected by the different substitutions of amino acids with identical overall hydrophobicity enabled effective resolution of these peptide analogs. We also demonstrated the ability of RP-HPLC to separate Ile- and allo-Ile-substituted analogs of a 26-residue α-helical antimicrobial peptide (AMP), with the substitution site towards the C-terminus of the α-helix. These peptides show different values of antibacterial activity and hemolytic activity, and different selectivity against bacteria and human cells. Our results underline the ability of RP-HPLC to resolve even difficult diasteromeric peptide mixtures as well as its value in monitoring very subtle hydrophobicity changes in de novo-designed AMP.

A smartphone-based enhanced colorimetric immunoassay for the detection of Trichinella spiralis infection.

Trichinellosis is a serious foodborne and zoonotic parasitic disease caused by Trichinella family. At present, the main on-site detection method for Trichinella spiralis (T. spiralis) infection is the lateral flow assay (LFA). Other diagnostic techniques for this parasite cannot be applied to on-site testing due to their reliance on special instruments. Here, we established an ELISA smartphone-based method for detecting anti-T. spiralis antibodies in pig serum. The use of horseradish peroxidase-labeled goat anti-pig IgG-modified gold nanoparticle (AuNPs@HRP-IgG) effectively increased the sensitivity of the method. The entire reaction was carried out at room temperature without the need for special instruments. A low-cost and portable device for imaging and processing experimental data was also developed. Validation analysis revealed that the specificity of the test was 98.89 %, while its sensitivity was 100.00 %. T. spiralis antibodies could be detected in pig serum beginning at 25 dpi after infection with the muscle larvae. This visual immunosensor facilitates on-site detection of T. spiralis, especially in regions lacking specialized laboratory equipment.

Agarose Hydrogel-Boosted One-Tube RPA-CRISPR/Cas12a Assay for Robust Point-of-Care Detection of Zoonotic Nematode Anisakis.

Rapid and accurate detection of the zoonotic nematode Anisakis is poised to control its epidemic. The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas-associated assay shows great potential in the detection of pathogenic microorganisms. The one-tube method integrated the CRISPR system with the recombinase polymerase amplification (RPA) system to avoid the risk of aerosol pollution; however, it suffers from low sensitivity due to the incompatibility of the two systems and additional manual operations. Therefore, in the present study, the agarose hydrogel boosted one-tube RPA-CRISPR/Cas12a assay was constructed by adding the CRISPR system to the agarose hydrogel, which avoided the initially low amplification efficiency of RPA caused by the cleavage of Cas12a and achieved reaction continuity. The sensitivity was 10-fold higher than that of the one-tube RPA-CRISPR/Cas12a system. This method was used for Anisakis detection within 80 min from the sample to result, achieving point-of-care testing (POCT) through a smartphone and a portable device. This study provided a novel toolbox for POCT with significant application value in preventing Anisakis infection.

Horizontal and Vertical Transmission of a Mycovirus Closely Related to the Partitivirus RhsV717 That Confers Hypovirulence in Rhizoctonia solani.

Rhizoctonia solani virus717 (RhsV717) was isolated from the Rhizoctonia solani (R. solani) AG-2 strain Rhs717. This study isolated a virus designated as Rhizoctonia solani partitivirus BS-5 (RsPV-BS5) from the R. solani AG-3 strain BS-5, the causal agent of tobacco target spot disease. The virus was identified as a strain of RhsV717. Transmission electron microscopy (TEM) images showed that RsPV-BS5 had virus particles with a diameter of approximately 40 nm. Importantly, it can be horizontally transmitted through hyphal anastomosis and vertically transmitted via sexual basidiospores. Furthermore, this study demonstrated that RsPV-BS5 infection significantly impedes mycelial growth and induces hypovirulence in tobacco leaves. Thus, RsPV-BS5 presents a promising avenue for biocontrolling tobacco target spot disease. Transcriptome analysis unveiled differential expression of four genes related to cell wall-degrading enzymes between two isogenic strains, 06-2-15V and 06-2-15. These findings shed light on the molecular mechanism through which RsPV-BS5 reduces host pathogenicity.

Rapid visual detection of anisakid nematodes using recombinase polymerase amplification and SYBR Green I.

Anisakidosis is a food-borne parasitic disease (FBPD) caused by the third-stage larvae of the family Anisakidae. Therefore, it is important to develop a simple, rapid and equipment-free detection method for anisakids in fish samples or seafood since current methods are time-consuming and require complex instruments. In this study, a recombinase polymerase amplification (RPA)-based method was established for the first time to detect anisakids by targeting the internal transcribed spacer (ITS) regions. The detection results were visualized by including SYBR Green I (SG) in the method. The sensitivity of RPA-SG assay was 102 copies per reaction of recombinant plasmid (within 20 min at 37°C), similar to quantitative real-time PCR (qPCR). The assay had high specificity for detecting anisakids against other related parasites and host fish. In addition, the assay was further used to detect fresh marine fish contaminated with anisakids and it showed high precision. These results indicate that the novel RPA-SG assay suitable for visual detection of anisakids in the field and food safety control.

Novel quaternary oxide semiconductor for the application of gas sensors with long-term stability.

In this paper, quaternary oxide semiconductor was applied as sensing material for the fabrication of gas sensors. One-step solvothermal method was utilized to synthesize the sensing material. Various characterization methods including XRD, XPS, SEM, HRTEM were employed to analyze the composition and structure of the sensing material. Composite composed of CuInW2O8 and CuWO4 was successfully prepared at last characterized by XRD result. The SEM result revealed the structure of the sensing material: nanoparticles assembled spindle-like nanostructure with ~200 nm long axis and ~60 nm short axis. Sensor based on the spindle-like nanostructures was systemically tested to acquire the information about the sensing properties. The sensor exhibited responses to acetone at the operating temperatures from 190 to 275 °C. The results showed that the sensor was more sensitive to acetone compared with other gases at the optimal operating temperature of 210 °C. The response of the sensor was also tested under the relative humidity from 25 RH% to 95 RH% at the operating temperature of 210 °C. The response variation was only 13.9%, demonstrating that the sensor possessed strong anti-humidity ability. It was worth noting that the sensor showed acceptable long-term stability compared with other acetone sensors. The gas sensing mechanism was also discussed here. This work might provide ideas for the development of novel sensitive materials for the application of gas sensors.

The DNA controllable peroxidase mimetic activity of MoS2 nanosheets for constructing a robust colorimetric biosensor.

The low activity of nanozymes, which work as an alternative to natural enzymes, limits their applications in the fabrication of biosensors, drawing increasing attention aimed at improving their catalytic capacity. In this work, the peroxidase-like activity of MoS2 nanosheets (NSs) was dramatically enhanced through DNA modification, and was 4.3-times higher than that of bare MoS2 NSs. Such an enhancement of catalytic activity was mainly ascribed to the increased affinity of the DNA/MoS2 NSs toward the substrate, TMB, further accelerating electron transfer from TMB to H2O2. On the basis of DNA-tuned MoS2 NS nanozyme activity, a colorimetric sensing platform was developed for the facile detection of carcinoembryonic antigen (CEA) in a sensitive manner. Interestingly, a convenient, affordable, and instrument-free portable test kit was fabricated to visually monitor CEA via rooting the aptamer/MoS2 NS system into an agarose hydrogel. Importantly, our work illuminates the feasibility of using DNA to enhance the catalysis of nanozymes and their application potential in the label-free, portable, and visual detection of aptamer-targeted biomolecules.

Lab in hydrogel portable kit: On-site monitoring of oxalate.

Oxalate is commonly employed as adjuvant of pesticide agent, causing renal injury of human even in trace residues. Despite the great achievements of the existing point-of-care testing (POCT) technology, accurate on-site screening of oxalate remains a tricky issue. To this aim, we proposed a "lab in a tube" platform which integrated portable hydrogel kit with smartphone for real-time monitoring of oxalate to achieve quantitatively precise analysis. In this work, a stimuli-responsive hydrogel-based kit was constructed via embedding manganese dioxide (MnO2) nanosheets into sodium alginate hydrogel system. Based on the intrinsic oxidase-like activity, MnO2 nanosheets-based nanozyme triggered color reaction by introducing a common sensing probe 3,3',5,5'-tetramethylbenzidine. Meanwhile, the presence of oxalate would decompose MnO2 nanosheets, inducing the decrease of nanozyme activity, which resulted in the color response of portable kit. Coupling with ImageJ software, the image information of kit captured via smartphone could be transduced into the hue intensity, which provided a directly quantitative tool to detect oxalate with a detection limit of 8.0 µmol L-1. This portable smartphone biosensor was successfully applied for screening urine sample within 10 min for high-throughput analysis (twelve samples) without the need for any advanced analytical instruments. Based on the merits of simple operation, cost-efficiency, and good selectivity, the availability of the miniaturized biosensor platform for POCT will achieve the requirements of routine screening and disease prevention.

High-activity Mo, S co-doped carbon quantum dot nanozyme-based cascade colorimetric biosensor for sensitive detection of cholesterol.

Nanozymes have drawn considerable attention because of their lower cost, higher stability and convenient preparation compared to protein enzymes. In the present work, Mo, S co-doped carbon quantum dots (Mo-CQDs) as a peroxidase mimic were used to fabricate a cascade colorimetric biosensor to detect cholesterol. The Mo-CQDs possess a robust peroxidase-like activity, and they can easily catalyze 3,3,5,5-tetramethylbenzidine (TMB) to produce an oxidized TMB in the presence of H2O2. The Mo, S doping in the carbon quantum dots (CQDs) notably boosts the yield of CQDs and may facilitate the electron transfer between TMB and H2O2, which further enhances the catalytic activity of CQDs. The colorimetric biosensor based on Mo-CQDs and cholesterol oxidase exhibited excellent selectivity and high sensitivity for cholesterol in the range of 0.01-1.0 mM along with a detection limit as low as 7 µM. The total cholesterol concentration in the serum sample was measured with satisfactory results and read out by the naked eye, indicating the potential application in clinical diagnosis and portable test kits.

Dendritic cells loaded with the lysate of tumor cells infected with Newcastle Disease Virus trigger potent anti-tumor immunity by promoting the secretion of IFN-γ and IL-2 from T cells.

Dendritic cells (DCs) are professional antigen-presenting cells that are pivotal in the generation and sustainability of antitumor immune responses. Whole tumor cell lysates (TCLs) have been used as sources of tumor antigens for the development of DC vaccines. However, the clinical outcomes of the use of TCL-based DC vaccines have so far been unsatisfactory because of the weak immunogenicity of tumor cells. To improve the efficacy of TCL-based DC vaccines, viruses have been used to enhance the immunity of TCLs and to further enhance the antigen delivery and antigen-presenting ability of DCs. The aim of the present study was to improve the antigen-presenting ability of DCs and to use them to effectively activate T lymphocytes. The present study demonstrated that DCs loaded with the lysate of Newcastle Disease Virus (NDV)-infected tumor cells (NDV-TCL) have increased levels of cluster of differentiation 80 (CD80), CD86, CD83 and human leukocyte antigen-antigen D-associated expression, compared with those loaded with TCL alone. The DCs loaded with the NDV-TCL promoted T-cell proliferation and antitumor cytokine secretion from T cells. These results indicated that loading DCs with NDV-TCL could enhance the antigen-presenting ability of the DCs. On the basis of the results of the present study, we hypothesize that this method of loading DCs with NDV-TCL can be used to develop novel DC vaccines for tumor immunotherapy in the future.

Hydrothermal synthesis of hierarchical CoO/SnO2 nanostructures for ethanol gas sensor.

In this work, ethanol gas sensor with high performance was fabricated successfully with hierarchical CoO/SnO2 heterojunction by two-steps hydrothermal method. The response value of CoO/SnO2 sensor is up to 145 at 250 °C when exposed to 100 ppm ethanol gas, which is much higher than that (13.5) of SnO2 sensor. These good sensing performances mainly attribute to the formation of the CoO/SnO2 heterojunction, which makes great variation of resistance in air and ethanol gas. Thus, the combination of n-type SnO2 and p-type CoO provides an effective strategy to design new ethanol gas sensors. The unique nanostructure also played an important role in detecting ethanol, due to its contribution in facilitating the transport rate of the ethanol gas molecules. Also, we provide a general two-step strategy for designing the heterojunction based on the SnO2 nanostructure.

High-response and low-temperature nitrogen dioxide gas sensor based on gold-loaded mesoporous indium trioxide.

Nitrogen dioxide (NO2), as a typical threatening atmospheric pollutant, is hazardous to the environment and human health. Thus, the development of a gas sensor with high response and low detection limit for NO2 detection is highly important. The highly ordered mesoporous indium trioxide (In2O3) prepared by simple nanocasting method using mesoporous silica as template and decorated with Au nanoparticles was investigated for NO2 detection. The prepared materials were characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. Characterization results showed that the samples exhibited ordered mesostructure and were successfully decorated with Au. The gas sensing performance of the sensors based on a series of Au-loaded mesoporous In2O3 were systematically investigated. The Au loading level strongly affected the sensing performance toward NO2. The optimal sensor, which was based on 0.5 wt% Au-loaded In2O3, displayed high sensor response and low detection limit of 10 ppb at low operating temperature of 65 °C. The excellent sensing properties were mainly attributed to the ordered mesoporous structure and the catalytic performance of Au. We believe that the Au-loaded mesoporous In2O3 can provide a promising platform for NO2 gas sensors with excellent performance.

Low-dose bortezomib increases the expression of NKG2D and DNAM-1 ligands and enhances induced NK and γδ T cell-mediated lysis in multiple myeloma.

Multiple myeloma (MM) is an incurable hematological malignancy, although bortezomib has markedly improved its outcomes. Growing clinical evidence indicates that enhancing induced natural killer (NK) or γδ T cells for infusion is useful in the treatment of MM. However, whether combination treatment with bortezomib and induced NK and γδ T cells further improves outcomes in MM, and how the treatments should be combined, remain unclear. Herein, we found that low-dose bortezomib did not suppress the viability of induced NK and γδ T cells, but did induce MM cell apoptosis. Importantly, low-dose bortezomib increased the expression of NKG2D and DNAM-1 ligands on MM cells, which sensitized the multiple myeloma cells to lysis by induced NK and γδ T cells. Our results suggested that combination treatment with low-dose bortezomib and induced NK or γδ T cells had a synergistic cytotoxic effect on MM cells. This study provided a proof of principle for the design of future trials and investigation of this combination therapeutic strategy for MM treatment.