ABSTRACT
Although bacteriophage-based biosensors hold promise for detecting Staphylococcus aureus in food products in a timely, simple, and sensitive manner, the associated targeting mechanism of the biosensors remains unclear. Herein, a colourimetric biosensor SapYZU11@ZnFe2O4, based on a broad-spectrum S. aureus lytic phage SapYZU11 and a ZnFe2O4 nanozyme, was constructed, and its capacity to detect viable S. aureus in food was evaluated. Characterisation of SapYZU11@ZnFe2O4 revealed its effective immobilisation, outstanding biological activity, and peroxidase-like capability. The peroxidase activity of SapYZU11@ZnFe2O4 significantly decreased after the addition of S. aureus, potentially due to blockage of the nanozyme active sites. Moreover, SapYZU11@ZnFe2O4 can detect S. aureus from various sources and S. aureus isolates that phage SapYZU11 could not lyse. This may be facilitated by the adsorption of the special receptor-binding proteins on the phage tail fibre and wall teichoic acid receptors of S. aureus. Besides, SapYZU11@ZnFe2O4 exhibited remarkable sensitivity and specificity when employing colourimetric techniques to rapidly determine viable S. aureus counts in food samples, with a detection limit of 0.87 × 102 CFU/mL. Thus, SapYZU11@ZnFe2O4 has broad application prospects for the detection of viable S. aureus cells on food substrates.
Subject(s)
Biosensing Techniques , Colorimetry , Food Contamination , Food Microbiology , Staphylococcus aureus , Staphylococcus aureus/isolation & purification , Biosensing Techniques/methods , Colorimetry/methods , Food Contamination/analysis , Staphylococcus Phages , Limit of DetectionABSTRACT
In this study, a colourimetric biosensor based on bacteriophage SapYZUM13 and an aminated Mn3O4 (Mn3O4-NH2) nanozyme was constructed and evaluated for its ability to detect Staphylococcus aureus in food. The biosensor had a detection time of 20 min, with a detection limit of 2 × 101 CFU/mL and recovery rate of 92.42-106.96%, indicating its high reliability and accuracy in detecting the food pathogen. Mechanistically, SapYZUM13@Mn3O4-NH2 exhibited oxidase-mimicking capability, producing O2â¢- free radicals which oxidise 3,3',5,5'-tetramethylbenzidine (TMB) to yield blue-coloured oxTMB. In the presence of S. aureus, the oxidase activity decreased remarkably owing to shielding of the nanozyme active sites. Moreover, SapYZUM13@Mn3O4-NH2 could detect viable S. aureus from various sources, likely because of the special receptor-binding proteins of SapYZUM13 adsorbing to the wall teichoic acids on the S. aureus cell surface. Thus, SapYZUM13@Mn3O4-NH2 has broad application prospects for the detection of viable S. aureus in various foods.
Subject(s)
Biosensing Techniques , Colorimetry , Food Microbiology , Staphylococcus aureus , Staphylococcus aureus/isolation & purification , Colorimetry/methods , Food Contamination/analysis , Limit of Detection , Oxides/chemistryABSTRACT
BACKGROUND: Human epidermal growth factor receptor 2 (HER2)-positive gastric cancer (GC) is a heterogeneous GC subtype characterized by the overexpression of HER2. To date, few specific targeted therapies have demonstrated durable efficacy in HER2-positive GC patients, with resistance to trastuzumab typically emerging within 1 year. However, the mechanisms of resistance to trastuzumab remain incompletely understood, presenting a significant challenge to clinical practice. METHODS: In this study, we integrated genetic screening and bulk transcriptome and epigenomic profiling to define the mechanisms mediating adaptive resistance to HER2 inhibitors and identify potential effective therapeutic strategies for treating HER2-positive GCs. RESULTS: We revealed a potential association between adaptive resistance to trastuzumab in HER2-positive GC and the expression of YES-associated protein (YAP). Notably, our investigation revealed that long-term administration of trastuzumab triggers extensive chromatin remodeling and initiates YAP gene transcription in HER2-positive cells characterized by the initial inhibition and subsequent reactivation. Furthermore, treatment of HER2-positive GC cells and cell line-derived xenografts (CDX) models with YAP inhibitors in combination with trastuzumab was found to induce synergistic effects through the AKT/mTOR and ERK/mTOR pathways. CONCLUSION: These findings underscore the pivotal role of reactivated YAP and mTOR signaling pathways in the development of adaptive resistance to trastuzumab and may serve as a promising joint target to overcome resistance to trastuzumab.
Subject(s)
Drug Resistance, Neoplasm , Proto-Oncogene Proteins c-akt , Receptor, ErbB-2 , Stomach Neoplasms , TOR Serine-Threonine Kinases , Transcription Factors , Trastuzumab , Humans , Stomach Neoplasms/drug therapy , Stomach Neoplasms/metabolism , Stomach Neoplasms/pathology , Stomach Neoplasms/genetics , Trastuzumab/pharmacology , Trastuzumab/therapeutic use , Receptor, ErbB-2/metabolism , TOR Serine-Threonine Kinases/metabolism , Animals , Mice , Proto-Oncogene Proteins c-akt/metabolism , Transcription Factors/metabolism , Antineoplastic Agents, Immunological/pharmacology , Antineoplastic Agents, Immunological/therapeutic use , YAP-Signaling Proteins/metabolism , Xenograft Model Antitumor Assays , Signal Transduction/drug effects , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Signal Transducing/genetics , Female , Cell Line, Tumor , Mice, Nude , Cell ProliferationABSTRACT
Although bacteriophage-based biosensors are promising tools for rapid, convenient, and sensitive detection of Staphylococcus aureus in food products, the effect of biosensors using temperate phages as biorecognition elements to detect viable S. aureus isolates remains unclear. In this study, three temperate S. aureus phages were isolated and their biological features (one-step growth, host range, pH stability, temperature stability, and adsorption rate) were evaluated as the biological element. The selected phage SapYZUs8 was immobilized on the nanozyme Cu-MOF via electrostatic interactions to generate SapYZUs8@Cu-MOF, and its detection performance in real food (skim milk and pork) was then evaluated. Compared with phages SapYZUm7 and SapYZUs16, phage SapYZUs8 exhibited a broader host range, greater pH stability (3-12), and a better absorption rate (92 %, 8 min) suitable for S. aureus detection, which is likely the result of the DNA replication (DNA helicase) and phage tail protein genes in the SapYZUs8 genome. Therefore, phage SapYZUs8 was fixed on Cu-MOF to generate SapYZUs8@Cu-MOF, which exhibited good sensitivity and specificity for rapid colourimetric detection of viable S. aureus. The method took <0.5 h, and the detection limit was 1.09 × 102 CFU/mL. In addition, SapYZUs8@Cu-MOF was successfully employed for the colourimetric detection of S. aureus in food samples without interference from different food additives, NaCl concentrations, or pH values. With these benefits, it allows rapid visual assessment of S. aureus levels.
Subject(s)
Bacteriophages , Staphylococcal Infections , Humans , Staphylococcus aureus , Colorimetry , Food , Staphylococcus Phages/geneticsABSTRACT
Bacillus licheniformis, a quick and strong biofilm former, is served as a persistent microbial contamination in the dairy industry. Its biofilm formation process is usually regulated by environmental factors including the divalent cation Ca2+. This work aims to investigate how different concentrations of Ca2+ change biofilm-related phenotypes (bacterial motility, biofilm-forming capacity, biofilm structures, and EPS production) of dairy B. licheniformis strains. The Ca2+ ions dependent regulation mechanism for B. licheniformis biofilm formation was further investigated by RNA-sequencing analysis. Results revealed that supplementation of Ca2+ increased B. licheniformis biofilm formation in a dose-dependent way, and enhanced average coverage and thickness of biofilms with complex structures were observed by confocal laser scanning microscopy. Bacterial mobility of B. licheniformis was increased by the supplementation of Ca2+ except the swarming ability at 20 mM of Ca2+. The addition of Ca2+ decreased the contents of polysaccharides but promoted proteins production in EPS, and the ratio of proteins/polysaccharides content was significantly enhanced with increasing Ca2+ concentrations. RNA-sequencing results clearly indicated the variation in regulating biofilm formation under different Ca2+ concentrations, as 939 (671 upregulated and 268 downregulated) and 951 genes (581 upregulated and 370 downregulated) in B. licheniformis BL2-11 were induced by 10 and 20 mM of Ca2+, respectively. Differential genes were annotated in various KEGG pathways, including flagellar assembly, two-component system, quorum sensing, ABC transporters, and related carbohydrate and amino acid metabolism pathways. Collectively, the results unravel the significance of Ca2+ as a biofilm-promoting signal for B. licheniformis in the dairy industry.
Subject(s)
Bacillus licheniformis , Bacillus licheniformis/genetics , Calcium , Dairy Products/microbiology , Biofilms , Bacteria/genetics , Polysaccharides , RNAABSTRACT
Herein, novel nanozyme mimics MoO3/MIL-125-NH2 were reported and conjugated with bacteriophages as a new electrochemical probe for high sensitivity and specific electrochemical detection of staphylococcus aureus. The excellent peroxidase-like activity of MoO3/MIL-125-NH2 composites was attributed to the integration of MIL-125-NH2 with MoO3, which can boost the generation of superoxide radicals (O⢠2-) and thus promote the oxidation of TMB in the presence of H2O2. In this work, two bacteriophages named SapYZU04 and SapYZU10 were isolated from sewage samples by using staphylococcus aureus YZUsa12 as the host. In comparison, MoO3/MIL-125-NH2@SapYZU04 was selected as a recognition agent. The DPV current declined linearly with staphylococcus aureus YZUsa12 concentration in the range of 101-108 CFU mL-1, with a low detection limit of 16 CFU mL-1 (S/N = 3). 20 strains including 13 host strains and 7 non-host strains were used to evaluate the selectivity of the proposed sensor. Regardless of the differences in the degrees of lytic performance for phage SapYZU04, all selected host strains can be screened with merely the same DPV current. Host spectrum-oriented bacteriophage sensing is of great importance for the practical application of bacteriophage-based biosensors in the future.
Subject(s)
Bacteriophages , Biosensing Techniques , Staphylococcal Infections , Humans , Staphylococcus aureus , Hydrogen Peroxide , PeroxidasesABSTRACT
T cell immunoglobulin and mucin domain-3 (TIM3; HAVCR2) is a transmembrane protein that exerts negative regulatory control over T cell responses. Studies have demonstrated an upregulation of TIM3 expression in tumor-infiltrating lymphocytes (TILs) in cancer patients. In this investigation, a series of monoclonal antibodies targeting TIM3 were produced by hybridoma technology. Among them, C23 exhibited favorable biological properties. To enable specific binding, we developed a 124I/125I-C23 radio-tracer via N-bromosuccinimide (NBS)-mediated labeling of the monoclonal antibody C23. Binding affinity and specificity were assessed using the 293T-TIM3 cell line, which overexpresses TIM3, and the parent 293T cells. Furthermore, biodistribution and in vivo imaging of 124I/125I-C23 were examined in HEK293TIM3 xenograft models and allograft models of 4T1 (mouse breast cancer cells) and CT26 (mouse colon cancer cells). Micro-PET/CT imaging was conducted at intervals of 4, 24, 48, 72, and/or 96 h post intravenous administration of 3.7-7.4 MBq 124I-C23 in the respective model mice. Additionally, immunohistochemistry (IHC) staining of TIM3 expression in dissected tumor organs was performed, along with an assessment of the corresponding expression of Programmed Death 1 (PD1), CD3, and CD8 in the tumors. The C23 monoclonal antibody (mAb) specifically binds to TIM3 protein with a dissociation constant of 23.28 nM. The 124I-C23 and 125I-C23 radio-tracer were successfully prepared with a labeling yield of 83.59 ± 0.35% and 92.35 ± 0.20%, respectively, and over 95.00% radiochemical purity. Stability results indicated that the radiochemical purity of 124I/125I-C23 in phosphate-buffered saline (PBS) and 5% human serum albumin (HSA) was still >80% after 96 h. 125I-C23 uptake in 293T-TIM3 cells was 2.80 ± 0.12%, which was significantly higher than that in 293T cells (1.08 ± 0.08%), and 125I-C23 uptake by 293T-TIM3 cells was significantly blocked at 60 and 120 min in the blocking groups. Pharmacokinetics analysis in vivo revealed an elimination time of 14.62 h and a distribution time of 0.4672 h for 125I-C23. Micro-PET/CT imaging showed that the 124I-C23 probe uptake in the 293T-TIM3 model significantly differed from that of the negative control group and blocking group. In the humanized mouse model, the 124I-C23 probe had obvious specific uptake in the 4T1 and CT26 models and maximum uptake at 24 h in tumor tissues (SUVmax (the maximum standardized uptake value) in 4T1 and CT26 humanized TIM3 murine tumor models: 0.59 ± 0.01 and 0.76 ± 0.02, respectively). Immunohistochemistry of tumor tissues from these mouse models showed comparable TIM3 expression. CD3 and CD8 cells and PD-1 expression were also observed in TIM3-expressing tumor tissues. The TIM3-targeting antibody C23 showed good affinity and specificity. The 124I/125I-C23 probe has obvious targeting specificity for TIM3 in vitro and in vivo. Our results suggest that 124I/125I-C23 is a promising tracer for TIM3 imaging and may have great potential in monitoring immune checkpoint drug efficacy.
Subject(s)
Antibodies, Monoclonal , Neoplasms , Animals , Humans , Mice , Antibodies, Monoclonal/chemistry , Cell Line, Tumor , Hepatitis A Virus Cellular Receptor 2/metabolism , Iodine Radioisotopes , Positron Emission Tomography Computed Tomography , Radiopharmaceuticals/pharmacokinetics , Tissue DistributionABSTRACT
Stress-activated signaling pathways orchestrate cellular behaviors and fates. Studying the precise role(s) of stress-activated protein kinases is challenging, because stress conditions induce adaptation and impose selection pressure. To meet this challenge, we have applied an optogenetic system with a single plasmid to express light-activated p38α or its upstream activator, MKK6, in conjunction with live-cell fluorescence microscopy. In starved cells, decaging of constitutively active p38α or MKK6 by brief exposure to UV light elicits rapid p38-mediated signaling, release of cytochrome c from mitochondria, and apoptosis with different kinetics. In parallel, light activation of p38α also suppresses autophagosome formation, similarly to stimulation with growth factors that activate PI3K/Akt/mTORC1 signaling. Active MKK6 negatively regulates serum-induced ERK activity, which is p38-independent as previously reported. Here, we reproduce that result with the one plasmid system and show that although decaging active p38α does not reduce basal ERK activity in our cells, it can block growth factor-stimulated ERK signaling in serum-starved cells. These results clarify the roles of MKK6 and p38α in dynamic signaling programs, which act in concert to actuate apoptotic death while suppressing cell survival mechanisms.
Subject(s)
Calcium-Calmodulin-Dependent Protein Kinases , Mitogen-Activated Protein Kinases , Mitogen-Activated Protein Kinases/metabolism , Calcium-Calmodulin-Dependent Protein Kinases/metabolism , Phosphatidylinositol 3-Kinases , p38 Mitogen-Activated Protein Kinases , MAP Kinase Kinase 6/geneticsABSTRACT
BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is a highly heterogeneous and aggressive malignancy with a poor prognosis. Pyroptosis triggered by gasdermins family proteins is reported vital for tumor microenvironment and cancer progression. However, pyroptosis-related gene expression and its relationship with immune infiltration and prognosis of HNSCC have not been fully defined. MATERIAL AND METHODS: RNA-sequencing data of HNSCC patients were acquired from The Cancer Genome Atlas (TCGA) database. A pyroptosis-related gene expression signature and infiltrated immune cells were analyzed. Univariate, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression and nomogram analyses were used to construct a clinical-molecular risk model for survival prognosis. RESULTS: HNSCC was classified into three different molecular subtypes based on the expression information of pyroptosis-related genes. Immune cell infiltration was demonstrated to be distinct between the three subtypes. The segregation of patients into the high-risk group and low-risk group, were carried out using the signature of differential expression genes (DEGs) signature among the three molecular subtypes. The precision of this signature was corroborated by Receiver operating characteristic curve (ROC) analysis with the 3-year area under time-dependent ROC curve (AUC) reaching 0.711. The risk model was validated in another dataset from the Gene Expression Omnibus (GEO) database. Subsequently we established a clinical-molecular nomogram which combined the risk score with age and stage. The calibration plots for predicting the overall survival rate of 1-, 3-, and 5-years indicated that the nomogram performs well. CONCLUSION: The expression signature that encompasses pyroptosis-related genes could be used as molecular classification for HNSCC and pyroptosis might be a promising therapeutic target in HNSCC.
Subject(s)
Head and Neck Neoplasms , Pyroptosis , Humans , Squamous Cell Carcinoma of Head and Neck/genetics , Transcriptome , Prognosis , Head and Neck Neoplasms/genetics , Tumor Microenvironment/geneticsABSTRACT
INTRODUCTION: Imaging with [68Ga]Ga-DOTA-TATE, [68Ga]Ga-DOTA-JR11 and [18F]AlF-NOTA-JR11 was performed to analyze differences among the three probes, and to analyze the correlation between the image and pathology parameters. METHOD: Tumor bearing mice with different positive rates of somatostatin receptor II (SSTR2) were established with HEK293-SSTR2 and HEK293 cells, and imaging was performed on the same mouse with [68Ga]Ga-DOTA-TATE, [68Ga]Ga-DOTA-JR11 and [18F]AlF-NOTA-JR11 at 20, 60 and 120 min. The image parameters were obtained, including the maximum standard uptake value (SUVmax), mean standard uptake value (SUVmean), standard deviation of SUVmean (SD), tumor volume and coefficient of variation (CoV). Immunohistochemistry of the tumor was performed after imaging to obtain positive rate of SSTR2. Statistical analysis was performed to analyze the differences among the three imaging techniques and the correlations between the relative imaging parameter and immunohistochemistry (IHC). RESULT: The SUVmax of [18F]AlF-NOTA-JR11 at 20 and 60 min was higher than that of [68Ga]Ga-DOTA-TATE (P=0.0015, 0.0035) and [68Ga]Ga-DOTA-JR11 (P=0.033, 0.019), and no significant difference was found in the other groups (P>0.05). There was a significant positive correlation between the positive rate and SUVmean of tumors with three tracers (P<0.05). However, a significant negative correlation between the positive rate and CoV was found only in the [68Ga]Ga-DOTA-TATE group at 60 min and 120 min (P=0.048, 0.026). CONCLUSION: [18F]AlF-NOTA-JR11 is more suitable for SSTR imaging within an hour than other two tracers. SUVmean of whole tumor can become an indicator for evaluating the positive rate of IHC, and the higher SUVmean of three tracers means a higher positive rate. However, the CoV is not applicable to the two antagonist tracers for evaluating the positive rate.
ABSTRACT
Evolution has diversified the mammalian proteome by the generation of protein isoforms that originate from identical genes, e.g., through alternative gene splicing or post-translational modifications, or very similar genes found in gene families. Protein isoforms can have either overlapping or unique functions and traditional chemical, biochemical, and genetic techniques are often limited in their ability to differentiate between isoforms due to their high similarity. This is particularly true in the context of highly dynamic cell signaling cascades, which often require acute spatiotemporal perturbation to assess mechanistic details. To that end, we describe a method for the selective perturbation of the individual protein isoforms of the mitogen-activated protein kinase (MAPK) p38. The genetic installation of a photocaging group at a conserved active site lysine enables the precise light-controlled initiation of kinase signaling, followed by investigation of downstream events. Through optical control, we have identified a novel point of crosstalk between two major signaling cascades: the p38/MAPK pathway and the extracellular signal-regulated kinase (ERK)/MAPK pathway. Specifically, using the photoactivated p38 isoforms, we have found the p38γ and p38δ variants to be positive regulators of the ERK signaling cascade, while confirming the p38α and p38ß variants as negative regulators.
ABSTRACT
Multidrug resistance (MDR) Staphylococcus aureus is frequently isolated from food products, and can cause severe clinical infection. Bacteriophage (phage) therapy is a promising biocontrol agent against MDR S. aureus in food contamination and clinical infections. In this study, the antimicrobial susceptibility of 47 S. aureus isolates from three swine farms, two slaughterhouses, and four markets (Yangzhou, China) were evaluated. The biological characteristics of four lytic S. aureus phages were compared and the lytic activity of phage SapYZU15 against MDR S. aureus was assessed using milk, fresh pork and a mouse model of subcutaneous abscess. The results showed that 28 S. aureus isolates (59.6%, 28/47) exhibited multiple antibiotic resistance to at least three different classes of antibiotics. Compared to SapYZU01, SapYZU02, and SapYZU03, SapYZU15 had a shorter latent period (10 min), larger burst size (322.00 PFU/cell), broader host range, wider temperature stability (-80 to 50 °C), and pH stability. Furthermore, SapYZU15 significantly reduces the counts of S. aureus in milk and pork (5.69 and 1.16 log colony-forming unit/mL, respectively) at 25 °C and controls the growth of S. aureus at 4 °C. Compared to the mice infected with S. aureus MRSA JCSC 4744 and cocktail (S. aureus YZUsa1, YZUsa4, YZUsa12, YZUsa14, and MRSA JCSC 4744), treatment with SapYZU15 led to faster tissue healing, less weight loss, and lower viable S. aureus counts in the murine abscess model. Moreover, prevention with SapYZU15 effectively inhibited abscess formation through a synergistic effect with pro-inï¬ammatory cytokines. Consequently, our results suggest that SapYZU15 is an effective strategy for controlling S. aureus contamination in food products, and possesses an immense potential to treat and prevent clinic infection caused by MDR S. aureus strains. The interactions and mechanisms between SapYZU15 and its bacterial host differed depending on the model, temperature, and multiplicity of infection (MOI).
Subject(s)
Bacteriophages , Staphylococcal Infections , Animals , Mice , Swine , Staphylococcus aureus , Abscess/drug therapy , Host Specificity , Staphylococcal Infections/drug therapyABSTRACT
Design and fabrication of feasible remediation composites for total Cr (Cr(T)) removal is still challenging but urgently required. Herein, eco-friendly expanded vermiculite (VE) is integrated with a photoactive covalent organic framework (COF) polymer, in which photoinduced electrons of surface anchored COF can freely transfer to Cr(VI) for chemical reduction, and layered expanded VE allows ion exchange between resultant Cr(III) cations and interlayered K+, Ca2+, Mg2+, Na+, etc. The Cr(T) removal capacities of the surface-modified VE with important parameters (solution pH value, initial Cr(VI) concentration, etc.) are discussed extensively to understand how to select the best conditions for optimum Cr(T) removal performance. More interestingly, from a circular economy view point, spent Cr-loading VE-based waste can serve as a photocatalyst towards oxidation conversion of ciprofloxacin and NO gas subsequently. Explanations for different effects on physicochemical properties as well as catalytic activities of the reused Cr-loading waste are given. This strategy could provide valuable and promising contribution towards the development of sustainable low-cost mineral materials for Cr(T) removal. These findings also shed new light on the research of recycling spent photocatalyst for resource and reutilization.
ABSTRACT
PURPOSE: Programmed cell death protein-1/ligand-1 (PD-1/L1) blockade has been a breakthrough in the treatment of patients with non-small cell lung cancer (NSCLC), but there is still a lack of effective methods to screen patients. Here we report a novel 68 Ga-labeled nanobody [68 Ga]Ga-THP-APN09 for PET imaging of PD-L1 status in mouse models and a first-in-human study in NSCLC patients. METHODS: [68 Ga]Ga-THP-APN09 was prepared by site-specific radiolabeling, with no further purification. Cell uptake assays were completed in the human lung adenocarcinoma cell line A549, NSCLC cell line H1975 and human PD-L1 gene-transfected A549 cells (A549PD-L1). The imaging to image PD-L1 status and biodistribution were investigated in tumor-bearing mice of these three tumor cell types. The first-in-human clinical translational trial was registered as NCT05156515. The safety, radiation dosimetry, biodistribution, and correlations of tracer uptake with immunohistochemical staining and major pathologic response (MPR) were evaluated in NSCLC patients who underwent adjuvant immunotherapy combined with chemotherapy. RESULTS: Radiosynthesis of [68 Ga]Ga-THP-APN09 was achieved at room temperature and a pH of 6.0-6.5 in 10 min with a high radiochemical yield (> 99%) and 13.9-27.8 GBq/µmol molar activity. The results of the cell uptake study reflected variable levels of surface PD-L1 expression observed by flow cytometry in the order A549PD-L1 > H1975 > A549. In small-animal PET/CT imaging, H1975 and A549PD-L1 tumors were clearly visualized in an 8.3:1 and 2.2:1 ratios over PD-L1-negative A549 tumors. Ex vivo biodistribution studies showed that tumor uptake was consistent with the PET results, with the highest A549PD-L1 being taken up the most (8.20 ± 0.87%ID/g), followed by H1975 (3.69 ± 0.50%ID/g) and A549 (0.90 ± 0.16%ID/g). Nine resectable NSCLC patients were enrolled in the clinical study. Uptake of [68 Ga]Ga-THP-APN09 was mainly observed in the kidneys and spleen, followed by low uptake in bone marrow. The radiation dose is within a reliable range. Tumor uptake was positively correlated with PD-L1 expression TPS (rs = 0.8763, P = 0.019). Tumor uptake of [68 Ga]Ga-THP-APN09 (SUVmax) in MPR patients was higher than that in non-MPR patients (median SUVmax 2.73 vs. 2.10, P = 0.036, determined with Mann-Whitney U-test). CONCLUSION: [68 Ga]Ga-THP-APN09 has the potential to be transformed into a kit-based radiotracer for rapid, simple, one-step, room temperature radiolabeling. The tracer can detect PD-L1 expression levels in tumors, and it may make it possibility to predict the response of PD-1 immunotherapy combined with chemotherapy. Confirmation in a large number of cases is needed. TRIAL REGISTRATION: Clinical Trial (NCT05156515). Registered 12 December 2021.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Humans , Mice , Animals , Positron Emission Tomography Computed Tomography/methods , Carcinoma, Non-Small-Cell Lung/diagnostic imaging , Carcinoma, Non-Small-Cell Lung/therapy , Gallium Radioisotopes , B7-H1 Antigen/metabolism , Tissue Distribution , Programmed Cell Death 1 Receptor/metabolism , Lung Neoplasms/diagnostic imaging , Positron-Emission Tomography/methods , Cell Line, TumorABSTRACT
Owing to the threats that Salmonella poses to public health and the abuse of antimicrobials, bacteriophage therapy against Salmonella is experiencing a resurgence. Although several phages have been reported as safe and efficient for controlling Salmonella, the genetic diversity and relatedness among Salmonella phages remain poorly understood. In this study, whole-genome sequences of 91 Salmonella bacteriophages were obtained from the National Center for Biological Information genome database. Phylogenetic analysis, mosaic structure comparisons, gene content analysis, and orthologue group clustering were performed. Phylogenetic analysis revealed four singletons and two major lineages (I-II), including five subdividing clades, of which Salmonella phages belonging to morphologically distinct families were clustered in the same clade. Chimeric structures (n = 31), holin genes (n = 18), lysin genes (n = 66), DNA packaging genes (n = 55), and DNA metabolism genes (n = 24) were present in these phages. Moreover, phages from different subdivided clusters harboured distinct genes associated with host cell lysis, DNA packaging, and DNA metabolism. Notably, phages belonging to morphologically distinct families shared common orthologue groups. Although several functional modules of phages SS1 and SE16 shared > 99% nucleotide sequence identity with phages SI2 and SI23, the major differences between these phages were the absence and replication of functional modules. The data obtained herein revealed the genetic diversity of Salmonella phages at genomic, structural, and gene content levels. The genetic diversity of Salmonella phages is likely owing to the acquisition, loss, and replication of functional modules.
Subject(s)
Bacteriophages , Salmonella Phages , Humans , Salmonella Phages/genetics , Phylogeny , Genome, Viral , Bacteriophages/genetics , Salmonella/genetics , DNA , Genetic VariationABSTRACT
Herein, we proposed surface engineering of magnetic peroxidase mimic using bacteriophage by electrostatic interaction to prepare bacteriophage SapYZU15 modified Fe3O4 (SapYZU15@Fe3O4) for colorimetric determination of S. aureus in food. SapYZU15@Fe3O4 exhibits peroxidase-like activity, catalyzing 3,3',5,5'-tetramethylbenzidine (TMB) chromogenic reaction. After introducing S. aureus, peroxidase-like activity of SapYZU15@Fe3O4 was specifically inhibited, resulting in deceleration of TMB chromogenic reaction. This phenomenon benefits from the presence of unique tail protein gene in the bacteriophage SapYZU15 genome, leading to a specific biological interaction between S. aureus and SapYZU15. On basis of this principle, SapYZU15@Fe3O4 can be employed for colorimetric determination of S. aureus with a limiting detection (LOD), calculated as low as 1.2 × 102 CFU mL-1. With this proposed method, colorimetric detection of S. aureus in food was successfully achieved. This portends that surface engineering of nanozymes using bacteriophage has great potential in the field of colorimetric detection of pathogenic bacterium in food.
Subject(s)
Bacteriophages , Peroxidase , Peroxidase/genetics , Peroxidase/metabolism , Staphylococcus aureus/genetics , Staphylococcus aureus/metabolism , Bacteriophages/genetics , Bacteriophages/metabolism , Colorimetry/methods , Peroxidases , Magnetic Phenomena , Hydrogen PeroxideABSTRACT
Two-dimensional material nanochannels with molecular-scale confinement can be constructed by Van der Waals assembly and show unexpected fluid transport phenomena. The crystal structure of the channel surface plays a key role in controlling fluid transportation, and many strange properties are explored in these confined channels. Here, we use black phosphorus as the channel surface to enable ion transport along a specific crystal orientation. We observed a significant nonlinear and anisotropic ion transport phenomenon in the black phosphorus nanochannels. Theoretical results revealed an anisotropy of ion transport energy barrier on the black phosphorus surface, with the minimum energy barrier along the armchair direction approximately ten times larger than that along the zigzag direction. This difference in energy barrier affects the electrophoretic and electroosmotic transport of ions in the channel. This anisotropic transport, which depends on the orientation of the crystal, may provide new approaches to controlling the transport of fluids.
ABSTRACT
Well-defined relative orientations and distances between chromophores are prerequisites for high-efficiency energy transfer, which can generally be realized by regularly assembling short peptide compounds with different absorption wavelengths and luminescence positions. Herein, a series of dipeptides are designed and synthesized, where the dipeptides contain different chromophores with several absorption bands. A co-self-assembled peptide hydrogel is prepared for artificial light-harvesting systems. The photophysical properties and assembly behavior of these dipeptide-chromophore conjugates in solution and hydrogel are systematically studied. As a result of the three-dimensional (3-D) self-assembly feature, effective energy transfer between donor and acceptor in the hydrogel system is achieved. These systems exhibit high antenna effect at a high donor/acceptor ratio (2564:1), which is characterized by an increase in the fluorescence intensity. Further, multiple molecules with different absorption wavelengths can be co-assembled as energy donors in order to achieve a wide spectrum of absorption. The method allows flexible light-harvesting systems to be realized. The ratio of energy donors to acceptors can be adjusted arbitrarily, and constructive motifs can be selected based on the application.
ABSTRACT
Citrobacter freundii is an important foodborne pathogen that can cause urethritis, bacteremia, necrotizing abscess, and meningitis in infants. In this study, a gas-producing isolate from vacuum-packed meat products was identified as C. freundii by 16S rDNA. In addition, a new virulent phage YZU-L1, which could specifically lyse C. freundii, was isolated from sewage samples in Yangzhou. Transmission electron microscopy showed that phage YZU-L1 had a polyhedral head of 73.51 nm in diameter and a long tail of 161.15 nm in length. According to phylogenetic analysis employing the terminase large subunit, phage YZU-L1 belonged to the Demerecviridae family and the Markadamsvirinae subfamily. The burst size was 96 PFU/cell after 30 min of latent period and 90 min of rising period. Phage YZU-L1 could maintain high activity at pH of 4-13, and resist 50 °C for up to 60 min. The complete genome of YZU-L1 was 115,014 bp double-stranded DNA with 39.94% G + C content, encoding 164 open reading frames (ORFs), without genes encoding for virulence, antibiotic resistance, or lysogenicity. Phage YZU-L1 treatment significantly reduced the viable bacterial count of C. freundii in a sterile fish juice model, which is expected to be a natural agent for the biocontrol of C. freundii in foods.