Dynamin 1xA interacts with Endophilin A1 via its spliced long C-terminus for ultrafast endocytosis.

Dynamin 1 mediates fission of endocytic synaptic vesicles in the brain and has two major splice variants, Dyn1xA and Dyn1xB, which are nearly identical apart from the extended C-terminal region of Dyn1xA. Despite a similar set of binding partners, only Dyn1xA is enriched at endocytic zones and accelerates vesicle fission during ultrafast endocytosis. Here, we report that Dyn1xA achieves this localization by preferentially binding to Endophilin A1 through a newly defined binding site within its long C-terminal tail extension. Endophilin A1 binds this site at higher affinity than the previously reported site, and the affinity is determined by amino acids within the Dyn1xA tail but outside the binding site. This interaction is regulated by the phosphorylation state of two serine residues specific to the Dyn1xA variant. Dyn1xA and Endophilin A1 colocalize in patches near the active zone, and mutations disrupting Endophilin A binding to the long tail cause Dyn1xA mislocalization and stalled endocytic pits on the plasma membrane during ultrafast endocytosis. Together, these data suggest that the specificity for ultrafast endocytosis is defined by the phosphorylation-regulated interaction of Endophilin A1 with the C-terminal extension of Dyn1xA.

HDAC7 is an immunometabolic switch triaging danger signals for engagement of antimicrobial versus inflammatory responses in macrophages.

The immune system must be able to respond to a myriad of different threats, each requiring a distinct type of response. Here, we demonstrate that the cytoplasmic lysine deacetylase HDAC7 in macrophages is a metabolic switch that triages danger signals to enable the most appropriate immune response. Lipopolysaccharide (LPS) and soluble signals indicating distal or far-away danger trigger HDAC7-dependent glycolysis and proinflammatory IL-1ß production. In contrast, HDAC7 initiates the pentose phosphate pathway (PPP) for NADPH and reactive oxygen species (ROS) production in response to the more proximal threat of nearby bacteria, as exemplified by studies on uropathogenic Escherichia coli (UPEC). HDAC7-mediated PPP engagement via 6-phosphogluconate dehydrogenase (6PGD) generates NADPH for antimicrobial ROS production, as well as D-ribulose-5-phosphate (RL5P) that both synergizes with ROS for UPEC killing and suppresses selective inflammatory responses. This dual functionality of the HDAC7-6PGD-RL5P axis prioritizes responses to proximal threats. Our findings thus reveal that the PPP metabolite RL5P has both antimicrobial and immunomodulatory activities and that engagement of enzymes in catabolic versus anabolic metabolic pathways triages responses to different types of danger for generation of inflammatory versus antimicrobial responses, respectively.

Sea-ATI unravels novel vocabularies of plant active cistrome.

The cistrome consists of all cis-acting regulatory elements recognized by transcription factors (TFs). However, only a portion of the cistrome is active for TF binding in a specific tissue. Resolving the active cistrome in plants remains challenging. In this study, we report the assay sequential extraction assisted-active TF identification (sea-ATI), a low-input method that profiles the DNA sequences recognized by TFs in a target tissue. We applied sea-ATI to seven plant tissues to survey their active cistrome and generated 41 motif models, including 15 new models that represent previously unidentified cis-regulatory vocabularies. ATAC-seq and RNA-seq analyses confirmed the functionality of the cis-elements from the new models, in that they are actively bound in vivo, located near the transcription start site, and influence chromatin accessibility and transcription. Furthermore, comparing dimeric WRKY CREs between sea-ATI and DAP-seq libraries revealed that thermodynamics and genetic drifts cooperatively shaped their evolution. Notably, sea-ATI can identify not only positive but also negative regulatory cis-elements, thereby providing unique insights into the functional non-coding genome of plants.

TLR4 phosphorylation at tyrosine 672 activates the ERK/c-FOS signaling module for LPS-induced cytokine responses in macrophages.

TLRs engage numerous adaptor proteins and signaling molecules, enabling a complex series of post-translational modifications (PTMs) to mount inflammatory responses. TLRs themselves are post-translationally modified following ligand-induced activation, with this being required to relay the full spectrum of proinflammatory signaling responses. Here, we reveal indispensable roles for TLR4 Y672 and Y749 phosphorylation in mounting optimal LPS-inducible inflammatory responses in primary mouse macrophages. LPS promotes phosphorylation at both tyrosine residues, with Y749 phosphorylation being required for maintenance of total TLR4 protein levels and Y672 phosphorylation exerting its pro-inflammatory effects more selectively by initiating ERK1/2 and c-FOS phosphorylation. Our data also support a role for the TLR4-interacting membrane proteins SCIMP and the SYK kinase axis in mediating TLR4 Y672 phosphorylation to permit downstream inflammatory responses in murine macrophages. The corresponding residue in human TLR4 (Y674) is also required for optimal LPS signaling responses. Our study, thus, reveals how a single PTM on one of the most widely studied innate immune receptors orchestrates downstream inflammatory responses.

Electrosynthesis of H2 O2 Promoted by π-π Interaction on a Metal-Free Carbon Catalyst.

The synthesis of hydrogen peroxide (H2 O2 ) through electrocatalytic oxygen reduction reaction is an ideal alternative to the current energy-intensive anthraquinone process, but developing cost-effective and high-efficiency electrocatalysts is still challenging. Herein, a metal-free graphitic carbon nitride/carbon nanotube (g-C3 N4 /CNT) hybrid catalyst can enhance H2 O2 production via π-π interaction is reported, achieving almost unity (97%) H2 O2 production at 0.57 V with high selectivity of over 92% across the wide potential range from 0.6 to 0 V. Other carbon materials with weak interaction with g-C3 N4 , such as acetylene black and super P, show markedly weakened H2 O2 production, indicating the importance of π-π interaction. Electron transfer kinetic analysis combined with density functional theory calculations indicates that the synergistic effect between g-C3 N4 and CNT enhances electron transfer and O2 activation between g-C3 N4 and CNT, leading to enhanced H2 O2 production performance. This work provides a complementary approach for H2 O2 production from oxygen reduction besides introducing oxygenated groups or heteroatom doping into carbon materials.

Vacancy Engineering in 2D Transition Metal Chalcogenide Photocatalyst: Structure Modulation, Function and Synergy Application.

Transition metal chalcogenides (TMCs) are widely used in photocatalytic fields such as hydrogen evolution, nitrogen fixation, and pollutant degradation due to their suitable bandgaps, tunable electronic and optical properties, and strong reducing ability. The unique 2D malleability structure provides a pre-designed platform for customizable structures. The introduction of vacancy engineering makes up for the shortcomings of photocorrosion and limited light response and provides the greatest support for TMCs in terms of kinetics and thermodynamics in photocatalysis. This work reviews the effect of vacancy engineering on photocatalytic performance based on 2D semiconductor TMCs. The characteristics of vacancy introduction strategies are summarized, and the development of photocatalysis of vacancy engineering TMCs materials in energy conversion, degradation, and biological applications is reviewed. The contribution of vacancies in the optical range and charge transfer kinetics is also discussed from the perspective of structure manipulation. Vacancy engineering not only controls and optimizes the structure of the TMCs, but also improves the optical properties, charge transfer, and surface properties. The synergies between TMCs vacancy engineering and atomic doping, other vacancies, and heterojunction composite techniques are discussed in detail, followed by a summary of current trends and potential for expansion.

Long-term immunogenicity and safety of heterologous boosting with a SARS-CoV-2 mRNA vaccine (SYS6006) in Chinese participants who had received two or three doses of inactivated vaccine.

The emerging new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) needs booster vaccination. We evaluated the long-term safety and immunogenicity of heterologous boosting with a SARS-CoV-2 messenger RNA vaccine SYS6006. A total of 1000 participants aged 18 years or more who had received two (Group A) or three (Group B) doses of SARS-CoV-2 inactivated vaccine were enrolled and vaccinated with one dose of SYS6006 which was designed based on the prototype spike protein and introduced mutation sites. Adverse events (AEs) through 30 days and serious AEs during the study were collected. Live-virus and pseudovirus neutralizing antibody (Nab), binding antibody (immunoglobulin G [IgG]) and cellular immunity were tested through 180 days. Solicited all, injection-site and systemic AEs were reported by 618 (61.8%), 498 (49.8%), and 386 (38.6%) participants, respectively. Most AEs were grade 1. The two groups had similar safety profile. No vaccination-related SAEs were reported. Robust wild-type (WT) live-virus Nab response was elicited with peak geometric mean titers (GMTs) of 3769.5 (Group A) and 5994.7 (Group B) on day 14, corresponding to 1602.5- and 290.8-fold increase versus baseline, respectively. The BA.5 live-virus Nab GMTs were 87.7 (Group A) and 93.2 (Group B) on day 14. All participants seroconverted for WT live-virus Nab. Robust pseudovirus Nab and IgG responses to wild type and BA.5 were also elicited. ELISpot assay showed robust cellular immune response, which was not obviously affected by virus variation. In conclusion, SYS6006 heterologous boosting demonstrated long-term good safety and immunogenicity in participants who had received two or three doses of SARS-CoV-2 inactivated vaccine.

The clinical efficacy of a daratumumab-based regimen in relapsed/refractory acute leukemia: a single-center experience.

Relapsed/refractory acute leukemia (R/R-AL) is associated with a low remission rate, short survival rate, and poor prognosis. Treating R/R-AL remains challenging as there is no standardized effective regimen; hence, there is a need for efficient therapies. CD38 expression has been observed in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Daratumumab is a humanized anti-CD38 monoclonal antibody used to treat multiple myeloma and has been reported to treat R/R-AL safely and effectively. The clinical data of 10 adult patients with R/R-AL who were treated with a daratumumab-based salvage regimen between July 2018 and May 2023 at our center were analyzed retrospectively. Seven AML and three ALL cases were included in the analysis. Seven (70%) patients showed responses to the treatments (complete response [CR], 60%; partial response [PR], 10%). Of the seven responders, three underwent allogenic stem cell transplantation (ASCT), including one who underwent a second ASCT. Among the five patients with R/R AML who had prior exposure to venetoclax, three achieved a therapeutic response (two CR and one PR) when re-treated with venetoclax in combination with daratumumab. The median follow-up time was 6.15 months (0.9-21 months). Overall survival and event-free survival rates at 12 months were 68.6% and 40.0%, respectively. The main adverse events included grade 3 febrile neutropenia (20%) and grade 3 hematological toxicities (60%). The daratumumab-based salvage regimen offers patients with R/R-AL the opportunity of remission with acceptable tolerability, creating the possibility of bridging ASCT.

PFASs in Cerebrospinal Fluids and Blood-CSF Barrier Permeability in Patients with Cognitive Impairment.

Attention has been drawn to the associations between PFASs and human cognitive decline. However, knowledge on the occurrence and permeability of PFASs in the brains of patients with cognitive impairment has not been reported. Here, we determined 30 PFASs in paired sera and cerebrospinal fluids (CSFs) from patients with cognitive impairment (n = 41) and controls without cognitive decline (n = 18). We revealed similar serum PFAS levels but different CSF PFAS levels, with lower CSF PFOA (median: 0.125 vs 0.303 ng/mL, p < 0.05), yet higher CSF PFOS (0.100 vs 0.052 ng/mL, p < 0.05) in patients than in controls. Blood-brain transfer rates also showed lower RCSF/Serum values for PFOA and higher RCSF/Serum values for PFOS in patients, implying potential heterogeneous associations with cognitive function. The RCSF/Serum values for C4-C14 perfluoroalkyl carboxylates exhibited a U-shape trend with increasing chain length. Logistic regression analyses demonstrated that CSF PFOS levels were linked to the heightened risk of cognitive impairment [odds ratio: 3.22 (1.18-11.8)] but not for serum PFOS. Toxicity inference results based on the Comparative Toxicogenomics Database suggested that PFOS in CSF may have a greater potential to impair human cognition than other PFASs. Our results contribute to a better understanding of brain PFAS exposure and its potential impact on cognitive function.

Engineering an enzyme-like catalytic sensor for on-site dual-mode evaluation of total antioxidant capacity.

A novel Fe-MoOx nanozyme, engineered with enhanced peroxidase (POD)-like activity through strategic doping and the creation of oxygen vacancies, is introduced to catalyze the oxidation of TMB with high efficiency. Furthermore, Fe-MoOx is responsive to single electron transfer (SET) and hydrogen atom transfer (HAT) mechanisms related to antioxidants and can serve as a desirable nanozyme for total antioxidant capacity (TAC) determination. The TAC colorimetric platform can reach a low LOD of 0.512 µM in solution and 24.316 µM in the smartphone-mediated RGB hydrogel (AA as the standard). As proof of concept, the practical application in real samples was explored. The work paves a promising avenue to design diverse nanozymes for visual on-site inspection of food quality.

Improved YOLOv8-Based Target Precision Detection Algorithm for Train Wheel Tread Defects.

Train wheels are crucial components for ensuring the safety of trains. The accurate and fast identification of wheel tread defects is necessary for the timely maintenance of wheels, which is essential for achieving the premise of conditional repair. Image-based detection methods are commonly used for detecting tread defects, but they still have issues with the misdetection of water stains and the leaking of small defects. In this paper, we address the challenges posed by the detection of wheel tread defects by proposing improvements to the YOLOv8 model. Firstly, the impact of water stains on tread defect detection is avoided by optimising the structure of the detection layer. Secondly, an improved SPPCSPC module is introduced to enhance the detection of small targets. Finally, the SIoU loss function is used to accelerate the convergence speed of the network, which ensures defect recognition accuracy with high operational efficiency. Validation was performed on the constructed tread defect dataset. The results demonstrate that the enhanced YOLOv8 model in this paper outperforms the original network and significantly improves the tread defect detection indexes. The average precision, accuracy, and recall reached 96.95%, 96.30%, and 95.31%.

A Simple-Structured Perovskite Wavelength Sensor for Full-Color Imaging Application.

In this study, simple-structured wavelength sensors were developed by depositing two back-to-back Au/MAPbI3/Au photodetectors on an MAPbI3 single crystal. This sensor could quantitatively distinguish wavelengths. Further device analysis showed that both photodetectors possess entirely disparate optoelectronic properties. Consequently, the as-developed wavelength sensor could accurately distinguish incident-light wavelengths ranging from 265 to 860 nm with a resolution of less than 1.5 nm based on the relation between the photocurrent ratios of both photodetectors and the incident light wavelengths. Notably, a high resolution and wide detection range are among the optimum reported values for such sensors and enable full-color imaging. Furthermore, technology computer-aided design (TCAD) simulations showed that a mechanism involved in distinguishing wavelengths is attributed to the wavelength-dependent photon generation rate in MAPbI3 single crystals. The high-performance MAPbI3 wavelength sensor can potentially drive the research progress of perovskites in wavelength recognition and full-color imaging.

Efficacy and Safety of Nerve Block for Postoperative Analgesia in Patients Undergoing Breast Cosmetic Surgery: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

BACKGROUND: To evaluate the postoperative analgesic efficacy and safety of nerve block (NB) in patients undergoing breast surgery for cosmetic purposes. METHODS: PubMed, Web of Science, Embase and Cochrane Libraries were searched from inception to September 2022, to identify all eligible randomized controlled trials (RCTs). Continuous data are presented as mean difference (MD) with 95% confidence intervals (CI), whereas dichotomous data are provided as odds ratios (OR) with 95% CI. This meta-analysis was performed in RevMan 5.4. RESULTS: A total of 10 RCTs with 565 patients were meta-analyzed. Compared to the control group, the pain score of the NB group was significantly lower at postoperative 2, 3-4, 6-8, 12-16 and 24 h. Opioid consumption in the first postoperative 24 h was significantly lower in the NB group (MD = - 9.02, 95% CI - 14.29 to - 3.75, P < 0.05), I2 = 95%). In addition, the NB group showed a prolonged time to first postoperative analgesic requirement (MD = 43.15, 95% CI 4.74-81.56, P < 0.05, I2 = 96%), decreased incidence of additional postoperative analgesia (OR 0.14, 95% CI 0.07-0.28, P < 0.05, I2 = 0%) and reduced incidence of postoperative nausea or vomiting (OR 0.33; 95% CI 0.22-0.48; P < 0.05; I2 = 0%). There was no significant difference in operation duration between the two groups. CONCLUSIONS: Nerve block is an effective and safe option for postoperative analgesia after breast cosmetic surgery. LEVEL OF EVIDENCE II: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Recurrence and Complications of Peri-operative Steroid Injection of Keloids: A Systematic Review and Meta-analysis.

Keloid scars are a particularly challenging fibroproliferative wound healing disorder with a variety of proposed management approaches including concurrent surgery and intralesional steroid injection. We aimed to identify the optimum time for triamcinolone injection of keloids, by comparing the recurrence and complication occurrence in patients who received pre-, intra- or post-operative injection. Studies reporting on the rate of recurrence and complication occurrence following treatment of keloid scarring with concurrent surgical excision and intralesional steroid injection were identified from the PubMed, Web of science and Embase databases. The I-squared (I2) statistic was used to quantify the variability in study estimates due to heterogeneity and to determine whether the fixed or random effect models will be employed. Publication bias was visualized through funnel plots and tested with the Egger's test. We found that the recurrence rate was significantly lower with post-operative injection compared to intra-operative injection (p < 0.001) and pre-operative injection (p = 0.009). A significant difference between intra-operative and pre-operative injection was not found (p = 0.46). In conclusion, post-operative steroid injection after surgical excision results in lower keloid recurrence compared to pre- and intra-operative injection.Level of Evidence IV "This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 ."

Exploring the Evolutionary History and Phylogenetic Relationships of Giant Reed (Arundo donax) through Comprehensive Analysis of Its Chloroplast Genome.

Giant reed (Arundo donax) is widely distributed across the globe and is considered an important energy crop. This study presents the first comprehensive analysis of the chloroplast genome of giant reed, revealing detailed characteristics of this species' chloroplast genome. The chloroplast genome has a total length of 137,153 bp, containing 84 protein-coding genes, 38 tRNA genes, and 8 rRNA genes, with a GC content of 39%. Functional analysis indicates that a total of 45 photosynthesis-related genes and 78 self-replication-related genes were identified, which may be closely associated with its adaptability and growth characteristics. Phylogenetic analysis confirmed that Arundo donax cv. Lvzhou No.1 belongs to the Arundionideae clade and occupies a distinct evolutionary position compared to other Arundo species. The findings of this study not only enhance our understanding of the giant reed genome but also provide valuable genetic resources for its application in biotechnology, bioenergy crop development, and ecological restoration.

Greenhouse gas emission characteristics and influencing factors of agricultural waste composting process: A review.

China, being a major agricultural nation, employs aerobic composting as an efficient approach to handle agricultural solid waste. Nevertheless, the composting process is often accompanied by greenhouse gas emissions, which are known contributors to global warming. Therefore, it is urgent to control the formation and emission of greenhouse gases from composting. This study provides a comprehensive analysis of the mechanisms underlying the production of nitrous oxide, methane, and carbon dioxide during the composting process of agricultural wastes. Additionally, it proposes an overview of the variables that affect greenhouse gas emissions, including the types of agricultural wastes (straw, livestock manure), the specifications for compost (pile size, aeration). The key factors of greenhouse gas emissions during composting process like physicochemical parameters, additives, and specific composting techniques (reuse of mature compost products, ultra-high-temperature composting, and electric-field-assisted composting) are summarized. Finally, it suggests directions and perspectives for future research. This study establishes a theoretical foundation for achieving carbon neutrality and promoting environmentally-friendly composting practices.

Effectiveness of teriparatide in in improving healing rates and bone-turnover markers of osteoporotic hip fracture: a meta-analysis.

Objective: To evaluate the effect of subcutaneous teriparatide therapy on fracture healing rate and change in bone mass density in osteoporotic hip fractures. METHODS: The meta-analysis was done from September to December 2022, and comprised literature search on Wanfang, CNKI, VIP, PubMed, Embase, Cochrane Library, and Web of Science databases from the establishment of the respective database till December 2022. The relevant journals of the library of Macao University of Science and Technology, China, were manually searched for randomised controlled trials of teriparatide in the treatment of osteoporotic hip fractures. The shortlisted studies were subjectd to Cochrane Risk of Bias tool and the Jadad Rating Scale. Meta-analysis was done using the RevMan 5.4 software provided by the Cochrane Collaboration Network. Fracture healing rate and bone mineral density were the primary outcome measures, while mortality, adverse events, malformations, complications, subsequent fractures, timed-up-and-go test, visual analogue scale score, and procollagen type I N-terminal propeptide were the secondary outcome measures. RESULTS: Of the 1,094 articles retrieved, 8(0.7%) randomised controlled trials were analysed. There were 744 patients; 372(50%) in the teriparatide group and 372(50%) in the control group. Fracture healing rate was not significantly different (p=0.82), while bone mineral density was significantly different between the groups (p<0.001). Mortality, adverse events, deformity, and complications were not significantly different (p>0.05), while subsequent fractures, timed-up-and-go score, visual analogue scale score and procollagen type I N-terminal propeptide were significantly different between the groups (p<0.05). Conclusion: The literature did not support teriparatide's ability to improve the healing rate of osteoporotic hip fractures, or to reduce mortality, adverse events, malformations, and complications. In addition, teriparatide could increase bone mineral density of osteoporotic hip fractures and the procollagen type I N-terminal propeptide value, alleviate hip pain, and reduce subsequent fracture rates. This trial is registered with PROSPERO with registration number CRD42022379832.

The transmembrane adapter SCIMP recruits tyrosine kinase Syk to phosphorylate Toll-like receptors to mediate selective inflammatory outputs.

Innate immune signaling by Toll-like receptors (TLRs) involves receptor phosphorylation, which helps to shape and drive key inflammatory outputs, yet our understanding of the kinases and mechanisms that mediate TLR phosphorylation is incomplete. Spleen tyrosine kinase (Syk) is a nonreceptor protein tyrosine kinase, which is known to relay adaptive and innate immune signaling, including from TLRs. However, TLRs do not contain the conserved dual immunoreceptor tyrosine-based activation motifs that typically recruit Syk to many other receptors. One possibility is that the Syk-TLR association is indirect, relying on an intermediary scaffolding protein. We previously identified a role for the palmitoylated transmembrane adapter protein SCIMP in scaffolding the Src tyrosine kinase Lyn, for TLR phosphorylation, but the role of SCIMP in mediating the interaction between Syk and TLRs has not yet been investigated. Here, we show that SCIMP recruits Syk in response to lipopolysaccharide-mediated TLR4 activation. We also show that Syk contributes to the phosphorylation of SCIMP and TLR4 to enhance their binding. Further evidence pinpoints two specific phosphorylation sites in SCIMP critical for its interaction with Syk-SH2 domains in the absence of immunoreceptor tyrosine-based activation motifs. Finally, using inhibitors and primary macrophages from SCIMP-/- mice, we confirm a functional role for SCIMP-mediated Syk interaction in modulating TLR4 phosphorylation, signaling, and cytokine outputs. In conclusion, we identify SCIMP as a novel, immune-specific Syk scaffold, which can contribute to inflammation through selective TLR-driven inflammatory responses.

Engineered DNAzyme Enables Homogeneous Detection of Cereulide via Polychromic Fluorescence Modality.

Cereulide, the exotoxin of emetic Bacillus cereus, has garnered considerable attention due to its capacity to produce foodborne poisonings and great chemical stability. Herein, a G-quadruplex-hemin DNAzyme-based biosensor was developed to detect cereulide in the homogeneous solution. Due to the special ring structure and high affinity to K+, cereulide can be attracted and intercalated into the G-quadruplex; thus, the properties of the G4 DNAzyme can be altered. The melting temperature (Tm) of the G4 DNAzyme in the presence or absence of cereulide was 58.75 and 50.10 °C, respectively, proving the intercalation of cereulide into the G4 DNAzyme. By using the polychromic fluorescence modality of CdTe quantum dots and o-phenylenediamine to assess the variation in the catalytic activity of the DNAzyme, the intercalation of cereulide had bidirectional effects in G4 DNAzyme-mediated reactions, showing that the fluorescence intensity of CdTe quantum dots displayed a linear relationship with the concentration of cereulide from 0.16 to 40 µg/mL with the limit of detection (LOD) of 0.10 µg/mL, while the fluorescence intensity of DAP exhibited a linear relationship with the concentration of cereulide from 0.02 to 40 µg/mL with the LOD of 0.01 µg/mL. It will be a perspective step of controlling cereulide as a hazardous material in food or the environment.

Design of an Antigen-Triggered Nanobody-Based Fluorescence Probe for PET Immunoassay to Detect Quinalphos in Food Samples.

Photoinduced electron-transfer (PET) immunoassay based on a fluorescence site-specifically labeled nanobody, also called mini Quenchbody (Q-body), exhibits extraordinary sensitivity and saves much time in the homogeneous noncompetitive mode and is therefore regarded as a valuable method. However, limited by the efficiency of both quenching and dequenching of the fluorescence signal before and after antigen binding associated with the PET principle, not all original nanobodies can be used as candidates for mini Q-bodies. Herein, with the anti-quinalphos nanobody 11A (Nb-11A) as the model, we, for the first time, adopt a strategy by combining X-ray structural analysis with site-directed mutagenesis to design and produce a mutant Nb-R29W, and then successfully generate a mini Q-body by labeling with ATTO520 fluorescein. Based on this, a novel PET immunoassay is established, which exhibits a limit of detection of 0.007 µg/mL with a detection time of only 15 min, 25-fold improved sensitivity, and faster by 5-fold compared to the competitive immunoassay. Meanwhile, the recovery test of vegetable samples and validation by the standard ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) both demonstrated that the established PET immunoassay is a novel, sensitive, and accurate detection method for quinalphos. Ultimately, the findings of this work will provide valuable insights into the development of triggered PET fluorescence probes by using existing antibody resources.