Phage cocktail alleviated type 2 diabetes by reshaping gut microbiota and decreasing proinflammatory cytokines.

Type 2 diabetes (T2D), a global health concern, is closely associated with the gut microbiota. Restoration of a balanced microbiota and intestinal homeostasis benefit therapy of T2D. Some special phages may selectively alter the gut microbiota without causing dysbiosis, such as MS2 and P22. However, scarcely systematic analysis of cascading effects triggered by MS2 and P22 phages on the microbiota, as well as interactions between specific gut bacteria and systemic metabolism, seriously inhibit the development of positive interventions of phages. Based on multi-omic analysis, we analyzed the intrinsic correlations among specific microbiota, their bioactive metabolites, and key indicators of T2D. We found that gavage of the MS2-P22 phage cocktail could significantly alter the gut microbiome to attenuate dysbiosis of diabetic C57BL/6 mice caused by high-fat diets (HFDs) and streptozotocin (STZ), by affecting microbial compositions as well as their metabolic pathways and metabolites, especially increasing amounts of short-chain fatty acid-producing (SCFA-producing) bacteria (e.g., Blautia and Romboutsia) and short-chain fatty acids (SCFAs). Correspondingly, a noteworthy reduction in the number of several opportunistic pathogens occurred, e.g., Candidatus Saccharimonas, Aerococcus, Oscillibacter, Desulfovibrio, and Clostridium sensu stricto 1. Synchronously, the levels of proinflammatory cytokines and lipopolysaccharide (LPS) were reduced to recover gut barrier function in T2D mice. These findings might benefit the development of a new dietary intervention for T2D based on phage cocktails. KEY POINTS: • Intestinal barrier integrity of T2D mice is improved by a phage cocktail • Negative relationship between Muribaculaceae and Corynebacterium reshaped gut microbiota • Acetate, propionate, and butyrate decreased the level of proinflammatory factors.

Microflora structure and functional capacity in Tibetan kefir grains and selenium-enriched Tibetan kefir grains: A metagenomic analysis.

Tibetan kefir grains (TKGs) are a complex protein-lipid-polysaccharide matrix composed of various microorganisms. Microorganisms have the benefit of being effective, secure, and controllable when used for selenium enrichment. In this study, selenium-enriched Tibetan kefir grains (Se-TKGs) were made, and the microbiology composition was analyzed through a metagenomic analysis, to explore the influence of selenium enrichment. The microbial composition of TKGs and Se-TKGs, as well as the probiotic species, quorum sensing system (QS) and functional genes were compared and evaluated. Lactobacillus kefiranofaciens was the most abundant microbial species in both communities. Compared with TKGs, Se-TKGs had a much higher relative abundance of acetic acid bacteria. Lactobacillus helveticus was the most common probiotic species both in TKGs and Se-TKGs. Probiotics with antibacterial and anti-inflammatory properties were more abundant in Se-TKGs. QS analysis revealed that Se-TKGs contained more QS system-associated genes than TKGs. Moreover, Kyoto Encyclopedia of Genes and Genomes analysis revealed that the pathway for human disease ko01501 had the greatest relative abundance in both TKGs and Se-TKGs. Compared with TKGs, Se-TKGs demonstrated a greater relative abundance of different drug resistance-related metabolic pathways. Additionally, linear discriminant analysis effect size was used to examine the biomarkers responsible for the difference between the two groups. In this study, we focused on the microbiological structure of TKGs and Se-TKGs, with the aim of establishing a foundation for a more thorough investigation of Se-TKGs and providing a basis for exploring potential future use.

Integrated transcriptomics and metabolomics reveal the mechanism of intestinal damage upon acute patulin exposure in mice.

Mycotoxin contamination has become a major food safety issue and greatly threatens human and animal health. Patulin (PAT), a common mycotoxin in the environment, is exposed through the food chain and damages the gastrointestinal tract. However, its mechanism of enterotoxicity at the genetic and metabolic levels remains to be elucidated. Herein, the intestinal histopathological and biochemical indices, transcriptome, and metabolome of C57BL/6 J mice exposed to different doses of PAT were successively assessed, as well as the toxicokinetics of PAT in vivo. The results showed that acute PAT exposure induced damaged villi and crypts, reduced mucus secretion, decreased SOD and GSH-Px activities, and enhanced MPO activity in the small intestine and mild damage in the colon. At the transcriptional level, the genes affected by PAT were dose-dependently altered in the small intestine and fluctuated in the colon. PAT primarily affected inflammation-related signaling pathways and oxidative phosphorylation in the small intestine and immune responses in the colon. At the metabolic level, amino acids decreased, and extensive lipids accumulated in the small intestine and colon. Seven metabolic pathways were jointly affected by PAT in two intestinal sites. Moreover, changes in PAT products and GST activity were detected in the small intestinal tissue but not in the colonic tissue, explaining the different damage degrees of the two sites. Finally, the integrated results collectively explained the toxicological mechanism of PAT, which damaged the small intestine directly and the colon indirectly. These results paint a clear panorama of intestinal changes after PAT exposure and provide valuable information on the exposure risk and toxic mechanism of PAT.

Removal of ochratoxin A in wine by Cryptococcus albidus and safety assessment of degradation products.

BACKGROUND: Ochratoxin A (OTA) is a mycotoxin that contaminates grape-based products and is extremely harmful to the health of the host. It is effectively removed by yeast during the fermentation of wine, whereas the removal mechanism of OTA remains unclear. Therefore, the present study aimed to investigate the removal mechanism of ochratoxin A by yeast and to evaluate the safety of its degradation products. RESULTS: Cryptococcus albidus (20-G) with better effect on ochratoxin A (OTA) was screened out in the main fermentation stage of wine. The results showed that 20-G removed OTA through biosorption and biodegradation. Intracellular enzymes played the main role (18.44%) and yeast cell walls adsorbed a small amount of OTA (8.44%). Furthermore, the identification of proteins in 20-G revealed that the decrease in OTA content was mainly a result of the action of peroxidase, and validation tests were carried out. By analyzing the degradation products of OTA, OTα and phenylalanine with lower toxicity were obtained. Animal experiments showed that the intervention of yeast 20-G reduced the damage and adverse effects caused by OTA toxicity to the mice. CONCLUSION: The present study demonstrates the mechanism of OTA removal by 20-G and the toxicity of OTA was reduced by peroxidase in 20-G. © 2023 Society of Chemical Industry.

Target-Induced AIE Effect Coupled with CRISPR/Cas12a System Dual-Signal Biosensing for the Ultrasensitive Detection of Gliotoxin.

Here, a novel rapid and ultrasensitive aptamer biosensor was designed for target-induced activation of AIE effect and followed by the activation of Crispr Cas12a (LbCpf1)-mediated cleavage to achieve dual-signal detection. The prepared DNA building blocks contain the target aptamer, ssDNA-Fc, and Activator1. In this system, the activation mode was divided into two steps. First, when the target interacts with the aptamers, the DNA building blocks would be disintegrated rapidly, releasing a mass of Ac1, generating ETTC-dsDNA aggregated to produce a fluorescence signal by the AIE effect. Second, with the release of Ac2, LbCpf1-crRNA was activated, which greatly improves the ssDNA-Fc cleavage efficiency to render signal amplification and ultrasensitive detection of the target. Satisfactorily, using this approach to detect gliotoxin, optimal conditions for detection was achieved for reducing the detection time to 55 min, achieving a low detection limit of 2.4 fM and a satisfactory linear in the range of 50 fM to 1 nM, which addressed the shortcoming of a weak electrochemical signal in previous sensors. The water-insoluble AIE material was coupled with DNA to obtain water-soluble ETTC-dsDNA and successfully introduced into the sensor system, with a low detection limit of 5.6 fM. Subsequently, the biosensor combined with handheld electrochemical workstation was successfully applied in the detection of gliotoxin in five actual samples, with a detection range of 32.0 to 2.09 × 108 pM. This strategy not only provides a novel and effective detection platform for mycotoxins in complex food matrices but also opens a promising avenue for various molecules detection in imaging and disease diagnosis.

Rethreading Design of Ratiometric roGFP2 Mimetic Peptide for Hydrogen Peroxide Sensing.

Reconstruction of the miniaturized peptide to mimic the tailored functions of protein has been attractive but challenging. Herein, initialized from the crystal structure of redox-sensitive green fluorescent protein-2 (roGFP2), we propose a practical approach to construct the roGFP2 mimetic peptide by rethreading the aromatic residues adjacent to the chromophore fragment. By fine-tuning the residues of peptides, a mini tetrapeptide (Cys-Phe-Phe-His) was designed, which can act as a hydrogen peroxide sensor using its ratiometric fluorescence. The roGFP2 mimetic tetrapeptide is biocompatible and photostable and has competitive fluorescent properties with roGFP2 by the virtue of its assembly induced emissions. We expand the ratiometric tetrapeptide for sensing hydrogen peroxide in acidic chambers. The results provide a promising approach for the artificial design of miniaturized peptides with the desired function.

Recent developments in antifungal lactic acid bacteria: Application, screening methods, separation, purification of antifungal compounds and antifungal mechanisms.

Fungal contamination of food, which causes large economic losses and public health problems, is a global concern. Chemical methods are typically used in the food industry to inhibit the growth of spoilage fungus, but there are several drawbacks of chemical methods. Thus, the development of consumer-friendly and ecologically sustainable biological preservation technology has become a hot spot in food research. As a natural biological control agent, lactic acid bacteria (LAB) is a good choice in food preservation due to its antifungal properties. In order to screen and identify new antifungal LAB and antifungal compounds, this review compares three screening methods (overlay method, agar diffusion method, and microplate inhibition method) of antifungal LAB and summarizes the separation and purification techniques of antifungal compounds. A discussion of the effects of LAB, media, temperature, pH, and incubation period on the antifungal activity of LAB to highlight the antifungal properties of LAB for future studies then follows. Additionally, the antifungal mechanism of LAB is elucidated from three aspects: 1) LAB cells, 2) antifungal compounds, and 3) co-cultivation. Finally, research regarding antifungal LAB in food preservation (fruits, vegetables, grain cereals, bakery products, and dairy products) is summarized, which demonstrates the potential application value of LAB in food.

Innovative beverage creation through symbiotic microbial communities inspired by traditional fermented beverages: current status, challenges and future directions.

Fermented beverages (FBs) are facing challenges in functional performance and flavor complexity, necessitating the development of new multi-functional options. Traditional fermented beverages (TFBs), both alcoholic and nonalcoholic, have gained increased attention for their health-promoting effects during the COVID-19 pandemic. This review summarized the primary commercially available probiotics of FBs, along with the limitations of single and mixed probiotic FBs. It also examined the recent research progress on TFBs, emphasizing the typical microbial communities (MC) of TFBs, and TFBs made from crops (grains, vegetables, fruits, etc.) worldwide and their associated functions and health benefits. Furthermore, the construction, technical bottlenecks of the synthetic MC involved in developing innovative FBs were presented, and the promising perspective of FBs was described. Drawing inspiration from the MC of TFBs, developing of stable and multifunctional FBs using synthetic MC holds great promise for beverage industry. However, synthetic MC suffers from structural instability and poorly acknowledged interaction mechanisms, resulting in disappointing results in FBs. Future researches should prioritize creating synthetic MC fermentation that closely resemble natural fermentation, tailored to meet the needs of different consumers. Creating personalized FBs with high-tech intelligence is vital in attracting potential consumers and developing novel beverages for the future.

Aspergillus cristatus attenuates DSS-induced intestinal barrier damage through reducing the oxidative stress, regulating short-chain fatty acid and inhibiting MAPK signaling pathways.

BACKGROUND: Probiotics are regarded as a promising strategy for relieving colitis caused by dextran sulfate sodium (DSS). One of the dominant probiotic fungi in Fuzhuan brick tea is identified as Aspergillus cristatus, but whether it can effectively improve colitis remains poorly understood. Here, the improving effect of A. cristatus on colitis was investigated. RESULTS: Our results showed that A. cristatus intervention prominently alleviated gut damage as evidenced by the inhibition of shortened colon length, goblet cell depletion, and histological injury. Mechanistically, after administration with low concentrations of A. cristatus H-1 and A. cristatus S-6, the expression of interleukin-6, tumor necrosis factor-α, interleukin-1ß, nitric oxide, and malondialdehyde were significantly downregulated, and the content of glutathione, catalase, interleukin-10, immunoglobulin G, claudin-1, occludin, and zonula occludens-1 were effectively upregulated. More importantly, live A. cristatus supplementation lightened DSS-induced gut barrier damage by suppressing activation of the mitogen-activated protein kinase (MAPK) signaling pathway, increasing the synthesis of short-chain fatty acids (SCFAs) and stimulating the increase in peroxisome proliferator-activated receptor γ expression. CONCLUSION: Together, A. cristatus can attenuate DSS-induced intestinal barrier damage through reducing the oxidative stress, regulating SCFA and inhibiting MAPK signaling pathways (P38/JNK/ERK). Our findings indicate that A. cristatus replenishment has potential as a new probiotic fungi to reduce DSS-induced colitis. © 2022 Society of Chemical Industry.

Lactobacillus coryniformis subsp. torquens T3 alleviates non-alcoholic fatty liver disease via reconstruction of the gut microbiota and redox system.

BACKGROUND: A high-fat diet (HFD) that induces obesity has become the most common type of diet worldwide, leading to serious global health issues. Obesity is associated with an increased risk of non-alcoholic fatty liver disease (NAFLD). Probiotic supplements have been shown to help alleviate obesity. The present study aimed to investigate the mechanism by which Lactobacillus coryniformis supsp. torquens T3 (T3L) alleviated NAFLD induced by HFD via reconstruction of the gut microbiota and redox system. RESULTS: The results showed that, compared with the HFD group, T3L inhibited obesity and relieved fat accumulation in the liver of mice with NAFLD. In addition, T3L inhibited liver inflammation and oxidative stress injury in NAFLD mice by regulating the lipopolysaccharide (LPS) inflammatory pathway in the liver. Furthermore, T3L changed the composition of the intestinal flora, reduced the abundance of harmful bacteria in the intestinal tract, enhanced the mechanical function of the intestinal barrier, and increased the short-chain fatty acid contents, thus inhibiting the secondary metabolite LPS, which directly causes liver damage through the portal vein. CONCLUSION: In summary, T3L ameliorated NAFLD induced by obesity through the liver-gut axis pathway, thus reducing oxidative stress and liver injury. © 2023 Society of Chemical Industry.

Color-Tunable Fluorescent Hierarchical Nanoassemblies with Concentration-Encoded Emission.

Cephalopods possess a dynamic coloration behavior to change their iridescence due to the concentration-induced optical properties of chromatophores and hierarchical assembly of reflectin. However, cephalopods rarely have iridescence in the darkfield. It would be interesting to develop color-tunable fluorescent hierarchical nanoassemblies with concentration-encoded emission. Herein, to construct the bioavailable fluorophore with dynamic coloration properties, a histidine-rich peptide is designed, which can self-assemble into hierarchical nanoassemblies stabilized by hydrogen bonds and π-π stacking interactions. The peptidyl nanoassemblies emit fluorescent iridescence, encompassing the blue to orange region due to the assembly-induced emission. The fluorescence of histidine-rich peptides is color-tunable and reversible, which can be dynamically controlled in a concentration-encoded mode. Due to the coloration ability of histidine-rich peptides, fluorescent polychromatic human cells are developed, highlighting its potential role as a fluorescent candidate for future applications such as bioimaging, implantable light-emitting diodes, and photochromic camouflage.

Application of nanostructures as antimicrobials in the control of foodborne pathogen.

Foodborne pathogens are the main cause of human foodborne diseases and pose a serious threat to food safety. The control of them has always been a significant issue in food industry. With good biocompatibility and stability, nanomaterials display excellent bactericidal properties against many kinds of bacteria. In this review, the generation and application of nanostructures as antibacterial in the control of foodborne pathogens was summarized. The antibacterial effects of photocatalytic and contact bacteriostatic nanomaterials agents were mainly introduced. The influence factors and mechanisms of nanomaterials on the inactivation of foodborne pathogens were displayed. The photocatalytic nanostructured bacteriostatic agents can produce reactive oxygen species (ROS) and lead to charge transfer, which result in damaging of cell wall and leakage of small molecules under light irradiation. In addition, metals and metal oxide nanoparticles can kill bacterial cells by releasing metal ions, forming ROS and electrostatic interaction with cell membrane. Besides, the synergistic action of nanoparticles with natural antibacterial agents can improve the stability of these agents and their bactericidal performance. These current researches provided a broader idea for the control of microorganisms in food.

Carbon dots based ratiometric fluorescent sensing platform for food safety.

Food safety has become a major global concern and the rapid detection of food nutritional ingredients and contaminants has aroused much more attention. Nanomaterials-based fluorescent sensing holds great potential in designing highly sensitive and selective detection strategies for food safety analysis. Carbon dots (CDs) possess tremendous prospects in fluorescent sensing food ingredients and contaminants due to their superior properties of chemical and photostability, highly fluorescence with tunability, and no/low-toxicity. Numerous endeavors are demanded to contribute to overcoming the challenge of lower sensitivity and selectivity of the sensors interfered by various components in intricate food matrices to ensure food safety and human health. Nanohybrid CDs based ratiometric fluorescent sensing with self-calibration is regarded as an efficient strategy for the CDs based sensors for the specific recognition of target analyte in the food matrices. This work is devoted to reviewing the development of nanohybrid CDs based ratiometric fluorescent sensing platform and the perspectives of the platform for food safety. The applications of nanohybrid CDs in sensing are summarized and the sensing mechanisms are briefly discussed.

Construction of ratiometric fluorescence sensor and test strip with smartphone based on dual-emission carbon dots for the specific detection of chlortetracycline.

Concerns about environmental and food contamination caused by chlortetracycline (CTC) residues have prompted people to explore efficient and convenient CTC monitoring platforms. However, the reported fluorescent probes generally fail to selectively detect CTC due to the structural similarity of tetracycline antibiotics. Herein, an intrinsic dual-emission carbon dots (D-CDs) ratiometric fluorescence sensor was prepared for highly sensitive and selective determination of CTC over other tetracyclines by one-step synthesis. The sensor exhibited a significant fluorescence enhancement at 425 nm after introducing CTC. The fluorescence "turn on" of the sensing system is due to aggregation-induced emission (AIE) phenomenon formed by hydrogen bonds and π conjugation promoting the specific recognition of CTC by D-CDs. The linear detection varied from 0.98 to 143.67 ng mL-1 with a low limit of detection (LOD) of 1.29 ng mL-1 (R2 = 0.998), which was lower than most reported in the literature. The D-CDs sensor was applied to detect CTC in spiked milk, blocked normal human serum, and fish samples with recoveries of 95.5-104.2% and relative standard deviations (RSDs) of 2.6%. Particularly, D-CDs based test papers with a smartphone were prepared for portable and visual detection of CTC by analyzing the various color changes of RGB of fluorescence color, with an LOD of 7.18 ng mL-1 (R2 = 0.9909). The fluorescence sensor designed in this work could be used as a rapid tool with high performance and selectivity for monitoring control in foods.

Inhibitory effects of lactobionic acid on Vibrio parahaemolyticus planktonic cells and biofilms.

Vibrio parahaemolyticus is the primary pathogenic bacteria associated with seafood-borne illnesses. Lactobionic acid (LBA) is an organic acid with multiple biological activities that has recently been a focus of interest as an antibacterial agent. The aim of this study was to investigate the inhibitory effects of LBA on Vibrio parahaemolyticus planktonic cells and biofilms. The minimum inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of LBA against Vibrio parahaemolyticus were both identified as 4 mg/mL. LBA exerted antimicrobial effects against planktonic Vibrio parahaemolyticus cells by damaging their membranes, as revealed by reduced intracellular ATP concentrations, increased protein leakage, abnormal cell morphology and diminished membrane integrity after treatment. At 1/16 × MIC and 1/8 × MIC, LBA inhibited biofilm formation and downregulated the expression of some biofilm-related genes, which was confirmed by crystal violet staining, field-emission scanning electron microscopy (FESEM) observations, and real-time quantitative PCR analysis. Moreover, LBA inactivated Vibrio parahaemolyticus cells within biofilms (on polystyrene and stainless steel surfaces), destroyed biofilm structures on stainless steel surfaces, and also reduced the levels of polysaccharides and proteins in the biofilms. Therefore, LBA is a potential low-cost agent that can be used to control planktonic Vibrio parahaemolyticus and its biofilms.

COVID-19-inspired "artificial virus" to combat drug-resistant bacteria by membrane-intercalation- photothermal-photodynamic multistage effects.

COVID-19 threatens human life because of the super destructiveness produced from its coronal morphology and strong transmembrane infection based on spike glycoprotein. Inspired by the coronal morphology of COVID-19 and its means of infecting, we designed an "artificial virus" with coronal morphology based on the concept of "defeating superbacteria with superviruses" by self-assembling a transacting activator of transduction peptide with triple-shell porous graphitic carbon nitride (g-C3N4) embedded with cobalt nanoparticles to forcefully infect methicillin-resistant Staphylococcus aureus (MRSA). The results confirmed that this "artificial virus" had unique properties of crossing the bacterial cell membrane barrier, heating the internal bacterial microenvironment and triggering ROS outbreak, based on its coronal morphology, membrane penetration, temperature-rising and heat insulation, oxidase-like activity and excellent visible-light harvesting properties. It had a high sterilization efficiency of 99.99% at 20 min, which was 18.6 times that of g-C3N4, and the efficiency remained at 99.99% after 3 rounds of recycling and reuse. Additionally, it can rapidly inactivate bacteria in river water and accelerate wound healing.

UiO-67 decorated on porous carbon derived from Ce-MOF for the enrichment and fluorescence determination of glyphosate.

A nanocomposite was prepared by loading UiO-67 nanoparticles onto porous carbon materials derived from Ce-MOF (Ce-PC) for fluorescence detection of glyphosate. The probe (UiO-67/Ce-PC) exhibits fluorescence emission at 414 nm as the response signal under excitation at 310 nm. The fluorescence enhancement mode of UiO-67 reduces the background interference, and the introduction of Ce-PC provide hierarchical nanostructure and large specific surface area that can increase the contact availability and improve the pre-enrichment effect, ensuring UiO-67/Ce-PC with superior sensitivity. The abundant metal hydroxyl group (M-O-H) of UiO-67/Ce-PC could recognize phosphoryl groups (-PO3H2) of glyphosate through ligand exchange, which synergizes with H-bonding interaction and electrostatic attraction to exhibit specificity toward glyphosate. The competitive coordination effects weaken the ligand-to-metal charge transfer (LMCT) and consequently induce the fluorescence recovery. The calibration plot of the fluorescence enhancement response of UiO-67/Ce-PC towards glyphosate was recorded in the range 0.02-30 µg mL-1 with a low limit of detection (LOD) of 0.0062 µg mL-1, which is superior to the pure UiO-67. In addition, the sensor exhibited high selectivity and satisfactory accuracy and precision with recoveries of 92.1-105.6% and RSDs below 3.4%. This work not only presents a feasible sensor for sensitive and selective determination of glyphosate from cereal samples, but also provides a promising strategy for the design of MOF-based nanocomposites to achieve trace detection of various pollutants.

Effects of fermentation with Lactobacillus fermentum 21828 on the nutritional characteristics and antioxidant activity of Lentinus edodes liquid.

BACKGROUND: Few studies to date have evaluated the use of Lactobacillus and Bifidobacterium in edible fungus fermentation. To obtain a fermented Lentinus edodes liquid product with good taste and effects, a strain with good fermentation performance from nine strains tested was selected, and the physicochemical properties and antioxidant capacity of the resulting product were evaluated. RESULTS: Lactobacillus fermentum 21828 exhibited adhesion, tolerance to low pH and bile salts, and good fermentation performance. The number of viable bacteria was 1.05 × 108 CFU mL-1 , and the extraction rate of crude polysaccharide from L. edodes was 2.79% after fermentation. The effects of fermentation on the contents and composition of nutrients in L. edodes liquid were marked, with changes in total soluble protein, total soluble sugar, total acid, and total phenol levels. The 2,2-diphenyl-1-picrylhydrazyl radical-scavenging rate in the fermentation liquid was 93.01%, which was significantly higher than that in non-fermented liquid (80.33%). Furthermore, analysis of volatile and 5'-nucleotide contents showed that fermentation altered the flavor of the product, whereas sensory evaluation showed that the fermented product was preferred. CONCLUSION: Our study demonstrated that the fermented L. edodes liquid exhibited better nutritional and functional properties, as well as sensory characteristics, compared with unfermented liquid. © 2021 Society of Chemical Industry.

Phage-based technologies for highly sensitive luminescent detection of foodborne pathogens and microbial toxins: A review.

Foodborne pathogens and microbial toxins are the main causes of foodborne illness. However, trace pathogens and toxins in foods are difficult to detect. Thus, techniques for their rapid and sensitive identification and quantification are urgently needed. Phages can specifically recognize and adhere to certain species of microbes or toxins due to molecular complementation between capsid proteins of phages and receptors on the host cell wall or toxins, and thus they have been successfully developed into a detection platform for pathogens and toxins. This review presents an update on phage-based luminescent detection technologies as well as their working principles and characteristics. Based on phage display techniques of temperate phages, reporter gene detection assays have been designed to sensitively detect trace pathogens by luminous intensity. By the host-specific lytic effects of virulent phages, enzyme-catalyzed chemiluminescent detection technologies for pathogens have been exploited. Notably, these phage-based luminescent detection technologies can discriminate viable versus dead microbes. Further, highly selective and sensitive immune-based assays have been developed to detect trace toxins qualitatively and quantitatively via antibody analogs displayed by phages, such as phage-ELISA (enzyme-linked immunosorbent assay) and phage-IPCR (immuno-polymerase chain reaction). This literature research may lead to novel and innocuous phage-based rapid detection technologies to ensure food safety.

Simultaneous electrochemical aptasensing of patulin and ochratoxin A in apple juice based on gold nanoparticles decorated black phosphorus nanomaterial.

Simultaneous detection of patulin (PAT) and ochratoxin A (OTA) in food products is in great demand, which can prevent toxins from being exposed to human and animal bodies. However, simultaneous detection of multiple targets still faces a challenge. Herein, we developed a novel electrochemical aptasensor for the simultaneous detection of PAT and OTA in apple juice based on gold nanoparticles decorated black phosphorus (AuNPs-BP) nanomaterial. AuNPs-BP function?/work? as a sensing platform for loading much different electrochemical signal molecules functionalized aptamers. In this context, methylene blue functionalized PAT aptamers (Mb-PAT-aptamers) and ferrocene functionalized OTA aptamers (Fc-OTA-aptamers) have been introduced here to fabricate the aptasensor. Fc close to electrode surface showed a strong signal, whereas Mb was far away from electrode surface so exhibited a weak signal in the absence of OTA and PAT. Two kinds of electrochemical signal changes have been recorded dependent on target of OTA and PAT concentrations. So, simultaneous detection of OTA and PAT is achieved. Under the optimum conditions, using this developed biosensor, PAT and OTA can be quantified at a linearity range of 0.01 × 10-7 µg·mL-1 ~ 0.10 µg·mL-1. In addition, it also has good selectivity, stability and repeatability. For the practical application, it shows promising performance for the simultaneous detection of PAT and OTA in apple juice.