Auxin receptor OsTIR1 mediates auxin signaling during seed filling in rice.

Cereal endosperm represents the most important source of the world's food. Nevertheless, the molecular mechanisms behind sugar import into rice (Oryza sativa) endosperm and their relationship with auxin signaling are poorly understood. Here, we report that auxin transport inhibitor response 1 (TIR1) plays an essential role in rice grain yield and quality via modulating sugar transport into endosperm. The fluctuations of OsTIR1 transcripts parallel to the early stage of grain expansion among those of the 5 TIR1/AFB (auxin-signaling F-box) auxin co-receptor proteins. OsTIR1 is abundantly expressed in ovular vascular trace, nucellar projection, nucellar epidermis, aleurone layer cells, and endosperm, providing a potential path for sugar into the endosperm. Compared to wild-type (WT) plants, starch accumulation is repressed by mutation of OsTIR1 and improved by overexpression of the gene, ultimately leading to reduced grain yield and quality in tir1 mutants but improvement in overexpression lines. Of the rice AUXIN RESPONSE FACTOR (ARF) genes, only the OsARF25 transcript is repressed in tir1 mutants and enhanced by overexpression of OsTIR1; its highest transcript is recorded at 10 d after fertilization, consistent with OsTIR1 expression. Also, OsARF25 can bind the promoter of the sugar transporter OsSWEET11 (SWEET, sugars will eventually be exported transporter) in vivo and in vitro. arf25 and arf25/sweet11 mutants exhibit reduced starch content and seed size (relative to the WTs), similar to tir1 mutants. Our data reveal that OsTIR1 mediates sugar import into endosperm via the auxin signaling component OsARF25 interacting with sugar transporter OsSWEET11. The results of this study are of great significance to further clarify the regulatory mechanism of auxin signaling on grain development in rice.

Electrochemical immunosensor for ultrasensitive detection of human papillomaviruse type 16 L1 protein based on Ag@AuNPs-GO/SPA.

Human papillomaviruse type 16 (HPV16) is a high-risk serotype. As the main protective antigen protein, L1 protein is also the target protein for diagnosis. A simple label free electrochemical immunosensor (ECIS) was fabricated for ultrasensitive detection of HPV16 L1 protein in this work. Quasi-spherical Ag@Au core-shell nanoparticles on graphene oxide (Ag@AuNPs-GO) was developed as current response amplifier and characterized by UV-Vis Spectroscopy, Transmission Electron Microscopy and energy dispersive X-ray spectroscopy. Staphylococcal protein A was decorated on the modified electrode and utilized to immobilized the Fc portion of the monoclonal antibody specific for HPV16 L1 protein. Cyclic Voltammetry, Differential Pulse Voltammetry and Electrochemical Impedance Spectroscopy were used to verify the electrochemical performance and interfacial kinetic property. The increased concentration of HPV16 L1 protein led to slow electron transport and linearly decreased differential pulse voltammetry peak current with a detection limit of 0.002 ng mL-1 and a wide linear relationship in the range of 0.005-400 ng mL-1at a regression coefficient (R2) of 0.9948. Furthermore, this ECIS demonstrated acceptable accuracy with good reproducibility, stability and selectivity, suggesting a promising immunological strategy for HPV typing and early screening.

Mesenchymal stem cells, as glioma exosomal immunosuppressive signal multipliers, enhance MDSCs immunosuppressive activity through the miR-21/SP1/DNMT1 positive feedback loop.

BACKGROUND: The immunosuppressive microenvironment in glioma induces immunotherapy resistance and is associated with poor prognosis. Glioma-associated mesenchymal stem cells (GA-MSCs) play an important role in the formation of the immunosuppressive microenvironment, but the mechanism is still not clear. RESULTS: We found that GA-MSCs promoted the expression of CD73, an ectonucleotidase that drives immunosuppressive microenvironment maintenance by generating adenosine, on myeloid-derived suppressor cells (MDSCs) through immunosuppressive exosomal miR-21 signaling. This process was similar to the immunosuppressive signaling mediated by glioma exosomal miR-21 but more intense. Further study showed that the miR-21/SP1/DNMT1 positive feedback loop in MSCs triggered by glioma exosomal CD44 upregulated MSC exosomal miR-21 expression, amplifying the glioma exosomal immunosuppressive signal. Modified dendritic cell-derived exosomes (Dex) carrying miR-21 inhibitors could target GA-MSCs and reduce CD73 expression on MDSCs, synergizing with anti-PD-1 monoclonal antibody (mAb). CONCLUSIONS: Overall, this work reveals the critical role of MSCs in the glioma microenvironment as signal multipliers to enhance immunosuppressive signaling of glioma exosomes, and disrupting the positive feedback loop in MSCs with modified Dex could improve PD-1 blockade therapy.

Electrochemical immunosensor nanoarchitectonics with the Ag-rGO nanocomposites for the detection of receptor-binding domain of SARS-CoV-2 spike protein.

As the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a grave threat to human life and health, it is essential to develop an efficient and sensitive detection method to identify infected individuals. This study described an electrode platform immunosensor to detect SARS-CoV-2-specific spike receptor-binding domain (RBD) protein based on a bare gold electrode modified with Ag-rGO nanocomposites and the biotin-streptavidin interaction system. The Ag-rGO nanocomposites was obtained by chemical synthesis and characterized by electrochemistry and scanning electron microscope (SEM). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to record the electrochemical signals in the electrode modification. The differential pulse voltammetry (DPV) results showed that the limit of detection (LOD) of the immunosensor was 7.2 fg mL-1 and the linear dynamic detection range was 0.015 ~ 158.5 pg mL-1. Furthermore, this sensitive immunosensor accurately detected RBD in artificial saliva with favorable stability, specificity, and reproducibility, indicating that it has the potential to be used as a practical method for the detection of SARS-CoV-2.

Advances in structure and function of auxin response factor in plants.

Auxin is a crucial phytohormone that has various effects on the regulators of plant growth and development. Auxin signal transduction is mainly controlled by two gene families: auxin response factor (ARF) and auxin/indole-3-acetic acid (Aux/IAA). ARFs are plant-specific transcription factors that bind directly to auxin response elements in the promoters of auxin-responsive genes. ARF proteins contain three conserved regions: a conserved N-terminal B3 DNA-binding domain, a variable intermediate middle region domain that functions in activation or repression, and a C-terminal domain including the Phox and Bem1p region for dimerization, similar to the III and IV elements of Aux/IAA, which facilitate protein-protein interaction through homodimerization of ARF proteins or heterodimerization of ARF and Aux/IAA proteins. In the two decades following the identification of the first ARF, 23 ARF members have been identified and characterized in Arabidopsis. Using whole-genome sequencing, 22, 25, 23, 25, and 36 ARF genes have been identified in tomato, rice, wheat, sorghum, and maize, respectively, in addition to which the related biofunctions of some ARFs have been reported. ARFs play crucial roles in regulating the growth and development of roots, leaves, flowers, fruits, seeds, responses to biotic and abiotic stresses, and phytohormone signal crosstalk. In this review, we summarize the research progress on the structures and functions of ARFs in Arabidopsis, tomato, and cereal crops, to provide clues for future basic research on phytohormone signaling and the molecular design breeding of crops.

EWSR1-induced circNEIL3 promotes glioma progression and exosome-mediated macrophage immunosuppressive polarization via stabilizing IGF2BP3.

BACKGROUND: Gliomas are the most common malignant primary brain tumours with a highly immunosuppressive tumour microenvironment (TME) and poor prognosis. Circular RNAs (circRNA), a newly found type of endogenous noncoding RNA, characterized by high stability, abundance, conservation, have been shown to play an important role in the pathophysiological processes and TME remodelling of various tumours. METHODS: CircRNA sequencing analysis was performed to explore circRNA expression profiles in normal and glioma tissues. The biological function of a novel circRNA, namely, circNEIL3, in glioma development was confirmed both in vitro and in vivo. Mechanistically, RNA pull-down, mass spectrum, RNA immunoprecipitation (RIP), luciferase reporter, and co-immunoprecipitation assays were conducted. RESULTS: We identified circNEIL3, which could be cyclized by EWS RNA-binding protein 1(EWSR1), to be upregulated in glioma tissues and to correlate positively with glioma malignant progression. Functionally, we confirmed that circNEIL3 promotes tumorigenesis and carcinogenic progression of glioma in vitro and in vivo. Mechanistically, circNEIL3 stabilizes IGF2BP3 (insulin-like growth factor 2 mRNA binding protein 3) protein, a known oncogenic protein, by preventing HECTD4-mediated ubiquitination. Moreover, circNEIL3 overexpression glioma cells drives macrophage infiltration into the tumour microenvironment (TME). Finally, circNEIL3 is packaged into exosomes by hnRNPA2B1 and transmitted to infiltrated tumour associated macrophages (TAMs), enabling them to acquire immunosuppressive properties by stabilizing IGF2BP3 and in turn promoting glioma progression. CONCLUSIONS: This work reveals that circNEIL3 plays a nonnegligible multifaceted role in promoting gliomagenesis, malignant progression and macrophage tumour-promoting phenotypes polarization, highlighting that circNEIL3 is a potential prognostic biomarker and therapeutic target in glioma.

miR-3184-3p enriched in cerebrospinal fluid exosomes contributes to progression of glioma and promotes M2-like macrophage polarization.

Liquid biopsy is a novel strategy for tumour diagnosis. The contents of cerebrospinal fluid (CSF) exosomes could reflect glioma status, hence sampling exosomes from CSF is a means of liquid biopsy for glioma. However, few studies have focused on the function of microRNAs in CSF exosomes. In this study, we found that miR-3184-3p was enriched in CSF exosomes in glioma patients and was downregulated after tumour resection. We found that miR-3184 facilitates glioma progression in two ways. On the one hand, miR-3184 directly promotes proliferation, migration, and invasion while inhibiting apoptosis in glioma. On the other hand, miR-3184 in glioma-derived exosomes polarizes macrophages to an M2-like phenotype, which further aggravates tumour progression. Overall, the current findings uncovered a new mechanism and highlighted the significant role of miR-3184 in glioma progression. Furthermore, exosomal miR-3184 could be a considerable factor with potential applications in glioma diagnosis and treatment in the future.

The PROTEIN PHOSPHATASE4 Complex Promotes Transcription and Processing of Primary microRNAs in Arabidopsis.

PROTEIN PHOSPHATASE4 (PP4) is a highly conserved Ser/Thr protein phosphatase found in yeast, plants, and animals. The composition and functions of PP4 in plants are poorly understood. Here, we uncovered the complexity of PP4 composition and function in Arabidopsis (Arabidopsis thaliana) and identified the composition of one form of PP4 containing the regulatory subunit PP4R3A. We show that PP4R3A, together with one of two redundant catalytic subunit genes, PROTEIN PHOSPHATASE X (PPX)1 and PPX2, promotes the biogenesis of microRNAs (miRNAs). PP4R3A is a chromatin-associated protein that interacts with RNA polymerase II and recruits it to the promoters of miRNA-encoding (MIR) genes to promote their transcription. PP4R3A likely also promotes the cotranscriptional processing of miRNA precursors, because it recruits the microprocessor component HYPONASTIC LEAVES1 to MIR genes and to nuclear dicing bodies. Finally, we show that hundreds of introns exhibit splicing defects in pp4r3a mutants. Together, this study reveals roles for Arabidopsis PP4 in transcription and nuclear RNA metabolism.

Pancancer landscape analysis of the thymosin family identified TMSB10 as a potential prognostic biomarker and immunotherapy target in glioma.

BACKGROUND: Thymosin family genes (TMSs), biologically important peptides with diverse intracellular and extracellular functions, have been shown to promote the progression of multiple cancers. However, multiomics characterization of TMSs and their role in human cancer prognosis has not been systematically performed. METHODS: We performed a comprehensive analysis of TMSs and thymosin ß10 (TMSB10) using multiomics data from more than 10,000 tumor samples of 33 cancer types from The Cancer Genome Atlas (TCGA). We used single-sample gene set enrichment analysis (ssGSEA) and the gene set variation analysis (GSVA) algorithm to investigate the differences in tumor microenvironment (TME) cell infiltration and functional annotation for individual tumor samples, respectively. The role of TMSB10 in the malignant progression of glioma, the promotion of macrophage infiltration,and immunosuppressive polarization, and the combination drug efficacy were assessed via biological function assays. RESULTS: We comprehensively assessed genomic mutations, expression dysregulation, prognosis and immunotherapeutic response across 33 human cancer samples and showed that TMSB10 is specifically overexpressed in almost all types of cancer tissues. Further pan-cancer analysis showed that TMSB10 is closely related to the biological function, immune regulation and prognosis of glioma. Similar results were also found in several public glioma cohorts and our Qilu local cohort. Further integration with other biological experiments revealed the key roles of TMSB10 in the malignant progression of glioma, the promotion of macrophage infiltration and immunosuppressive polarization. We also identified multiple drugs targeting cells with high TMSB10 expression and validated that knockdown of TMSB10 improved the efficacy of selumetinib (a MEK1/2 inhibitor approved by the FDA for the treatment of neurofibromatosis-associated tumors) and anti-PD1 treatment in glioma. CONCLUSION: These results indicate that TMSB10 holds promise as a novel prognostic marker and therapeutic target, providing a theoretical basis for the development of more effective and targeted clinical treatment strategies for glioma patients.

Screening and identification of B cell epitope of the nucleocapsid protein in SARS-CoV-2 using the monoclonal antibodies.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus that causes the coronavirus disease (COVID-19). It is confirmed that nucleocapsid (N) protein is closely related to viral pathogenesis, modulation of host immune response, RNA transcription, and replication and virus packaging. Therefore, the N protein is a preponderant antigen target for virus detection. The codon-optimized N gene was designed according to the encoding characteristics of insect cells and inserted into pFastBacTM1 vector with 6 × His-tag-fused N protein for expression in insect sf21 cells. Six anti-N mAbs (4G3, 5B3, 12B6, 18C7-A2, 21H10-A3, 21H10-E9) were prepared by recombinant N protein. The mAbs showed high titers, antibody affinity, and reactivity with the SARS-CoV-2 N protein. Then, fourteen overlapped peptides that covered the intact N protein were synthesized (N1-N14). Peptide N14 was identified as the main linear B-cell epitope region via peptide-ELISA and dot-blot assay, and this region was truncated gradually until mapping the peptide 401-DFSKQLQQ-408. Simultaneously, compared with the sequence of variants of concern (VOCs) and variants of interest (VOIs) strains among the several countries, epitope 401-DFSKQLQQ-408 is very conservative among them. The findings provide new guidance for the design and detection of COVID-19 targets. KEY POINTS: • The N protein was optimized according to the insect cell codon preference and was highly expressed. • The monoclonal antibodies prepared in this study were shown high antibody titers and high affinity. • Monoclonal antibodies were used to map the epitope 401-408 amino acids of N protein for the first time in this study.

Exosomal miR-1246 from glioma patient body fluids drives the differentiation and activation of myeloid-derived suppressor cells.

Glioma is a heterogeneous cellular environment in which immune cells play critical roles in tumor progression. Myeloid-derived suppressor cells (MDSCs) contribute to the formation of the immunosuppressive microenvironment of glioma; however, how glioma cells interact with MDSCs and how this interaction affects the function of other immune cells are unclear. Glioma cells can systemically communicate with immune cells via the secretion of exosomes, which contain microRNAs (miRNAs). Leveraging miRNA sequencing of exosomes, we identified enrichment of miR-1246 in glioma-derived exosomes and exosomes isolated from the cerebrospinal fluid (CSF) of glioma patients. We demonstrated that miR-1246 drives the differentiation and activation of MDSCs in a dual specificity phosphatase 3 (DUSP3)/extracellular signal­regulated kinase (ERK)-dependent manner. In addition, postoperative CSF exosomal miR-1246 expression was found to be associated with the glioma recurrence rate. Hypoxia, a well-recognized feature of the glioblastoma microenvironment, increased miR-1246 levels in glioma-derived exosomes by enhancing miR-1246 transcription and selective packaging via upregulation of POU class 5 homeobox 1 (POU5F1) and heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1). Importantly, we identified a mechanism of 2-methoxyestradiol, a microtubule inhibitor currently undergoing clinical trials for glioblastoma. 2-Methoxyestradiol suppresses MDSC activation by inhibiting hypoxia-driven exosomal miR-1246 expression in glioma cells and PD-L1 expression in MDSCs.

Circulating levels of Elabela in pregnant women with missed abortion.

ObjectiveThis study aimed to detect Elabela concentrations in the serum of Missed abortion (MA) and compare them with the healthy pregnancies.Materials and methodsThis retrospective case-control study was performed in the second affiliated hospital, Xi'an Jiaotong University March 2019 to September 2019. A total of 108 healthy (35 early, 36 middle and 37 late) pregnant women and 25 (early gestational stage) MA patients were involved. Demographic and clinical characteristics were recorded. The concentration of plasma Elabela was examined using ELISA.ResultsThe level of plasma Elabela was increased in early and middle stages and decreased in late stage of healthy pregnant women. Maternal serum Elabela levels were significantly lower in MA patients (4.59 ± 1.23 ng/mL) compared to healthy pregnant women (5.77 ± 1.21 ng/mL, p < 0.01).ConclusionMaternal circulating levels of Elabela were significantly lower in MA patients than in healthy pregnant women. We consider that Elabela might be a crucial biomarker of the pathophysiologic process in MA.

Differential diagnosis of the infection caused by wild-type or CD2v-deleted ASFV strains by quantum dots-based immunochromatographic assay.

African swine fever (ASF), a highly contagious and lethal disease, poses a tremendous threat and burden to the swine industry worldwide. Lack of available vaccines or treatments leaves rapid diagnosis as the key tool to control the disease. Quantum dots (QDs) are unique fluorescent semiconductor nanoparticles, highly versatile for biological applications. In this study, we developed a quantum dots-based fluorescent immunochromatographic assay (QDs-FICA) using CD2v as the diagnosis antigen to detect ASFV antibodies. The titre of the test strip was 1 : 5·12 × 105 . In addition, the strip was highly specific to anti-ASFV serum and had no cross-reaction with CSFV, PPV, PRRSV, PCV-2, PRV and FMDV. Moreover, a comparative test of 71 clinical samples showed that the coincidence rate was 85·92% between the test strip and the commercial ELISA kit (coated with p30, p62 and p72). The QDs-FICA can be used to detect ASFV antibodies, which is meaningful for the surveillance, control and purification of ASF.

A Universal Fluorescent Immunochromatography Assay Based on Quantum Dot Nanoparticles for the Rapid Detection of Specific Antibodies against SARS-CoV-2 Nucleocapsid Protein.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the pathogenic agent leading to COVID-19. Due to high speed of transmission and mutation rates, universal diagnosis and appropriate prevention are still urgently needed. The nucleocapsid protein of SARS-CoV-2 is considered more conserved than spike proteins and is abundant during the virus' life cycle, making it suitable for diagnostic applications. Here, we designed and developed a fluorescent immunochromatography assay (FICA) for the rapid detection of SARS-CoV-2-specific antibodies using ZnCdSe/ZnS QDs-conjugated nucleocapsid (N) proteins as probes. The nucleocapsid protein was expressed in E.coli and purified via Ni-NTA affinity chromatography with considerable concentration (0.762 mg/mL) and a purity of more than 90%, which could bind to specific antibodies and the complex could be captured by Staphylococcal protein A (SPA) with fluorescence displayed. After the optimization of coupling and detecting conditions, the limit of detection was determined to be 1:1.024 × 105 with an IgG concentration of 48.84 ng/mL with good specificity shown to antibodies against other zoonotic coronaviruses and respiratory infection-related viruses (n = 5). The universal fluorescent immunochromatography assay simplified operation processes in one step, which could be used for the point of care detection of SARS-CoV-2-specific antibodies. Moreover, it was also considered as an efficient tool for the serological screening of potential susceptible animals and for monitoring the expansion of virus host ranges.

OsRLR4 binds to the OsAUX1 promoter to negatively regulate primary root development in rice.

Root architecture is one of the most important agronomic traits that determines rice crop yield. The primary root (PR) absorbs mineral nutrients and provides mechanical support; however, the molecular mechanisms of PR elongation remain unclear in rice. Here, the two loss-of-function T-DNA insertion mutants of root length regulator 4 (OsRLR4), osrlr4-1 and osrlr4-2 with longer PR, and three OsRLR4 overexpression lines, OE-OsRLR4-1/-2/-3 with shorter PR compared to the wild type/Hwayoung (WT/HY), were identified. OsRLR4 is one of five members of the PRAF subfamily of the regulator chromosome condensation 1 (RCC1) family. Phylogenetic analysis of OsRLR4 from wild and cultivated rice indicated that it is under selective sweeps, suggesting its potential role in domestication. OsRLR4 controls PR development by regulating auxin accumulation in the PR tip and thus the root apical meristem activity. A series of biochemical and genetic analyses demonstrated that OsRLR4 functions directly upstream of the auxin transporter OsAUX1. Moreover, OsRLR4 interacts with the TRITHORAX-like protein OsTrx1 to promote H3K4me3 deposition at the OsAUX1 promoter, thus altering its transcription level. This work provides insight into the cooperation of auxin and epigenetic modifications in regulating root architecture and provides a genetic resource for plant architecture breeding.

Metformin alleviates oxidative stress-induced senescence of human lens epithelial cells via AMPK activation and autophagic flux restoration.

Cataracts are the leading cause of blindness worldwide owing to the increasing proportion of elderly individuals in the population. The purpose of this study was to investigate whether metformin could alleviate the occurrence and development of age-related cataract (ARC) and the underlying mechanism. In the present study, we established a senescence model induced by oxidative stress, which was confirmed by measuring ß-galactosidase activity, qRT-PCR and Western blotting. In addition, we showed that metformin alleviated the oxidative stress-induced senescence of HLE-B3 cells via the activation of AMPK. Next, we provided evidence that oxidative stress impaired autophagic flux and induced lysosomal dysfunction. Subsequently, we found that metformin restored autophagic flux that had been impaired by oxidative stress by activating AMPK. Additionally, we found that metformin suppressed HLE-B3 cell senescence by improving lysosomal function and inactivating mTOR. Furthermore, the inactivation of AMPK, impairment of autophagic flux and lysosomal dysfunction were observed in the human lens epithelium of ARC. In summary, our data suggest that the activation of AMPK may be a potential strategy for preventing ARC, and metformin may be an emerging candidate to alleviate the formation and development of ARC.

Exosomes derived from hypoxic glioma deliver miR-1246 and miR-10b-5p to normoxic glioma cells to promote migration and invasion.

Hypoxia is an important feature of the tumor microenvironment and is associated with glioma progression and patient outcome. Exosomes have been implicated in the intercellular communication in the tumor microenvironment. However, the effects of hypoxic glioma exosomes on glioma migration and invasion and the underlying mechanisms remain poorly understood. In this study, we found that exosomes derived from hypoxic glioma cells (H-GDEs) promoted normoxic glioma migration and invasion in vitro and in vivo. Given that exosomes can regulate recipient cell functions by delivering microRNAs, we further revealed miR-1246 and miR-10b-5p were upregulated significantly in H-GDEs and delivered to normoxic glioma cells by H-GDEs. Moreover, we determined the clinical relevance of miR-1246 and miR-10b-5p in glioma patients. Subsequent investigations indicated that miR-1246 and miR-10b-5p markedly induced glioma migration and invasion in vitro and in vivo. Finally, we demonstrated that miR-1246 and miR-10b-5p induced glioma migration and invasion by directly targeting FRK and TFAP2A respectively. In conclusion, our findings suggest that the hypoxic microenvironment stimulates glioma to generate miR-1246- and miR-10b-5p-rich exosomes that are delivered to normoxic glioma cells to promote their migration and invasion; treatment targeting miR-1246 and miR-10b-5p may impair the motility of gliomas, providing a novel direction for the development of antitumor therapy.

Multiple fluorescence immunoassay for the simultaneous detection of Zearalenone and Ochratoxin A.

A sensitive and accurate multiple fluorescence immunoassay for the simultaneous quantitative detection of Zearalenone (ZEN) and Ochratoxin A (OTA) in single spot based on multicolor quantum dots (QDs) labeling was developed for the first time. Two kinds of ZnCdSe/ZnS (core/shell) QDs with maximum emission wavelengths at 520 nm (green) and 610 nm (orange-red) were selected as marking materials, respectively. The anti-ZEN-mAb-QDs and anti-OTA-mAb-QDs were designed as the immune fluorescent probes. Fluorescence was measured at the same excitation wavelength and two different emission wavelengths to determine each target. The procedure for QDs-based multiple fluorescence labeled immunosorbent assay (M-FLISA) was developed. The 50% inhibition concentrations (IC50) of ZEN and OTA were 0.034 and 1.175 ng/mL. Moreover, the limits of detection (LOD) for the simultaneous determination were 0.0239 and 2.339 ng/g for ZEN and OTA in maize, respectively. In addition, the recoveries ranged from 93.15 to 101.90% for ZEN and from 95.29 to 102.43% for OTA, with the coefficient variation (CV) of 2.70-8.86% and 3.51-6.22% respectively. There was good consistency between the M-FLISA and high performance liquid chromatography (HPLC) results, which confirmed that the M-FLISA was suitable for the simultaneous quantitative detection of various mycotoxins.

A Thermotolerant Marine Bacillus amyloliquefaciens S185 Producing Iturin A5 for Antifungal Activity against Fusarium oxysporum f. sp. cubense.

Fusarium wilt of banana (also known as Panama disease), is a severe fungal disease caused by soil-borne Fusarium oxysporum f. sp. cubense (Foc). In recent years, biocontrol strategies using antifungal microorganisms from various niches and their related bioactive compounds have been used to prevent and control Panama disease. Here, a thermotolerant marine strain S185 was identified as Bacillus amyloliquefaciens, displaying strong antifungal activity against Foc. The strain S185 possesses multiple plant growth-promoting (PGP) and biocontrol utility properties, such as producing indole acetic acid (IAA) and ammonia, assimilating various carbon sources, tolerating pH of 4 to 9, temperature of 20 to 50 °C, and salt stress of 1 to 5%. Inoculation of S185 colonized the banana plants effectively and was mainly located in leaf and root tissues. To further investigate the antifungal components, compounds were extracted, fractionated, and purified. One compound, inhibiting Foc with minimum inhibitory concentrations (MICs) of 25 µg/disk, was identified as iturin A5 by high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) and nuclear magnetic resonance (NMR). The isolated iturin, A5, resulted in severe morphological changes during spore germination and hyphae growth of Foc. These results specify that B. amyloliquefaciens S185 plays a key role in preventing the Foc pathogen by producing the antifungal compound iturin A5, and possesses potential as a cost-effective and sustainable biocontrol strain for Panama disease in the future. This is the first report of isolation of the antifungal compound iturin A5 from thermotolerant marine B. amyloliquefaciens S185.

An Electrochemical Immunosensor Based on SPA and rGO-PEI-Ag-Nf for the Detection of Arsanilic Acid.

A sensitive electrochemical immunosensor was prepared for rapid detection of ASA based on arsanilic acid (ASA) monoclonal antibody with high affinity. In the preparation of nanomaterials, polyethyleneimine (PEI) improved the stability of the solution and acted as a reducing agent to generate reduced graphene oxide (rGO) with relatively strong conductivity, thereby promoting the transfer of electrons. The dual conductivity of rGO and silver nanoparticles (AgNPs) improved the sensitivity of the sensor. The synthesis of nanomaterials were confirmed by UV-Vis spectroscopy, X-ray diffraction, transmission electron microscopy and scanning electron microscopy. In the optimal experiment conditions, the sensor could achieve the detection range of 0.50-500 ng mL-1 and the limit of detection (LOD) of 0.38 ng mL-1 (S/N = 3). Moreover, the sensor exhibited excellent specificity and acceptable stability, suggesting that the proposed sensor possessed a good potential in ASA detection. Thus, the as-prepared biosensor may be a potential way for detecting other antibiotics in meat and animal-derived foods.