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1.
Food Chem ; 461: 140893, 2024 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-39178539

RESUMEN

In this study, ovalbumin (OV) and sodium alginate (SA), two macromolecular complexes, were coagulated into the emulsifier (OV/SA), which stabilized soybean oil by electrostatic interaction, hydrophobic interactions, and hydrogen bonding. The structure of OV/SA and properties of OV/SA Pickering emulsion were investigated. Additionally, the effect of emulsions on the gel and protein properties of hairtail surimi was studied. The results revealed that with the increasing concentration of OV/SA, the particle size and zeta potential value (negative value) of the emulsion initially decreased and then increased, while the rheological properties gradually improved. Compared with the surimi gel directly supplemented with soybean oil, the addition of emulsion enhanced gel strength, whiteness, water holding capacity, and hydrophobic interactions, resulting in a more stable gel network structure. In summary, incorporating emulsion into surimi at the same lipid content not only maintained its gel properties but also improved its color and compensated for lipid loss.


Asunto(s)
Alginatos , Emulsiones , Geles , Ovalbúmina , Tamaño de la Partícula , Reología , Ovalbúmina/química , Emulsiones/química , Alginatos/química , Animales , Geles/química , Interacciones Hidrofóbicas e Hidrofílicas , Bagres , Emulsionantes/química , Productos Pesqueros/análisis
2.
Int J Biol Macromol ; 276(Pt 2): 133940, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39025179

RESUMEN

In this work, the hydroxypropyl-ß-cyclodextrin (HP-ß-CD)/Epicatechin (EC) clathrate compounds were rapidly prepared based on an ultrasound-mediated method, and Polycaprolactone (PCL)/Locust bean gum (LBG) nanofibers loaded clathrate compounds were fabricated by electrostatic spinning (ELS) for fruit packaging. The results of infrared spectrum and crystal type analysis proved that clathrate compounds were successfully prepared. With the addition of clathrate compounds, the diameter of fibers increased from 553.43 to 1273.47 nm, and hydrogen bonds were formed between clathrate compounds and fibrous membranes, which improved the thermal stability, reduced the crystallinity, and enhanced the hydrophilicity and gas permeability of fibrous membranes. The fibrous membranes indicated sustained release of EC for 240 h, retaining the activity of EC and demonstrating good bacteriostatic ability in vitro and in vivo. The test results showed that the antibacterial fibrous membranes prepared in this work have a positive application prospect for fruit packaging.


Asunto(s)
2-Hidroxipropil-beta-Ciclodextrina , Embalaje de Alimentos , Frutas , Galactanos , Mananos , Nanofibras , Gomas de Plantas , Poliésteres , Gomas de Plantas/química , Galactanos/química , Embalaje de Alimentos/métodos , Nanofibras/química , Poliésteres/química , Frutas/química , Mananos/química , 2-Hidroxipropil-beta-Ciclodextrina/química , Antibacterianos/farmacología , Antibacterianos/química , Interacciones Hidrofóbicas e Hidrofílicas
3.
Int J Biol Macromol ; 276(Pt 1): 133839, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39004248

RESUMEN

Functional compounds (FCs) had some functions, which are affected easily by digestion and transmembrane transport leading to low absorption rates, such as lutein, quercetin, xylo-oligosaccharide. Protein from blue foods is a potential bioactive compound, which had higher bioavailability, especially for bioactive peptides (BBPs). The BBPs has great limitations, especially the variability under pepsin digestion. However, the limitation of single FCs and BBPs in bioavailability might can be complemented by mixture of different bioactive compounds. Therefore, this review provides an in-depth study on the function and mechanism of different FCs/BBPs and their mixtures. Specifically, digestion effect of mixtures on function and transmembrane transport mechanisms of different bioactive compounds were exhibited to elaborate interactions between BBPs and FCs in delivery systems (function and bioavailability). Combination of FCs/BBPs could enhance bioactive compounds function by mutual complement of function mechanisms, as well as improving the function after digestion by regulating digestion process. Moreover, transmembrane absorption and transport of FCs/BBPs also could be facilitated by mixtures due to complement of transmembrane mechanism (endocytosis, protein channels, cell bypass way). This manuscript lays a foundation for the development of active ingredient bioavailability in functional food processing.


Asunto(s)
Digestión , Alimentos Funcionales , Humanos , Transporte Biológico , Disponibilidad Biológica , Animales , Modelos Biológicos , Péptidos/metabolismo , Péptidos/química
4.
Food Res Int ; 191: 114691, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39059947

RESUMEN

To better enhance printing effects meanwhile casting functionality, antioxidation and absorption of bioactive component in printed Ca2+-nano starch (NS)-lutein (L)-surimi were investigated. Results shown that Ca2+-NS-L promoted surimi printability due to enhanced gel strength and denser structure. Mixing Ca2+-NS-L endowed printed surimi with antioxidation (DPPH, ABTS, hydroxyl radical, Fe2+ reduction were 42 %, 79 %, 65 %, 0.104 mg·mL-1, respectively) due to the ability of lutein with more -OH groups and conjugate bonds to capture free radicals. It also manifested in cellular antioxidation that Ca2+-NS-L-surimi regulated the level of Nrf2 to protect gene expression of antioxidases (SOD, CAT, GSH-Px increased by 30-180 %, compared to damaged cells) through keap1-Nrf2-ARE pathway. Additionally, lutein absorption and transportation of Ca2+-NS-L-surimi increased by 20 %, compared to NS-L. Possibly, combination of samples and membrane was facilitated by surface hydrophobic, promoting endocytosis. Meanwhile, digestive surimi (peptides) with acidic-alkaline amino acids and negative charges made samples be attracted and moved in bypass parts under electrostatic traction and repulsion (electrostatic domain) to promote transport process. Also, Ca2+ facilitated CaM expression in membrane and formed Ca2+ channel by combining with CaM to accelerate entry of samples into cells. Conclusively, Ca2+-NS-L both strengthened printability of surimi and antioxidation, promoting application of printed functional surimi.


Asunto(s)
Antioxidantes , Calcio , Luteína , Factor 2 Relacionado con NF-E2 , Impresión Tridimensional , Almidón , Humanos , Antioxidantes/metabolismo , Luteína/metabolismo , Luteína/química , Células Hep G2 , Almidón/metabolismo , Almidón/química , Células CACO-2 , Calcio/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Nanopartículas/química
5.
Nature ; 631(8021): 531-536, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39020034

RESUMEN

The pursuit of discovering new high-temperature superconductors that diverge from the copper-based model1-3 has profound implications for explaining mechanisms behind superconductivity and may also enable new applications4-8. Here our investigation shows that the application of pressure effectively suppresses the spin-charge order in trilayer nickelate La4Ni3O10-δ single crystals, leading to the emergence of superconductivity with a maximum critical temperature (Tc) of around 30 K at 69.0 GPa. The d.c. susceptibility measurements confirm a substantial diamagnetic response below Tc, indicating the presence of bulk superconductivity with a volume fraction exceeding 80%. In the normal state, we observe a strange metal behaviour, characterized by a linear temperature-dependent resistance extending up to 300 K. Furthermore, the layer-dependent superconductivity observed hints at a unique interlayer coupling mechanism specific to nickelates, setting them apart from cuprates in this regard. Our findings provide crucial insights into the fundamental mechanisms underpinning superconductivity, while also introducing a new material platform to explore the intricate interplay between the spin-charge order, flat band structures, interlayer coupling, strange metal behaviour and high-temperature superconductivity.

6.
J Pharm Biomed Anal ; 248: 116269, 2024 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-38906072

RESUMEN

Corrections to the article based on comments published by Dr Acree, various models, including the modified Apelblat model, the λh model, the Jouyban-Acree model, the SUN model and the CNIBS/R-K model, recalculated, obtained new parameters and relative absolute percentage deviations.


Asunto(s)
Solubilidad , Solventes , Termodinámica , Solventes/química , Modelos Químicos , Fosforilcolina/análogos & derivados , Fosforilcolina/química
7.
Spectrochim Acta A Mol Biomol Spectrosc ; 317: 124404, 2024 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-38723465

RESUMEN

Peroxynitrite is one of the important reactive oxygen species in the human body and is closely related to the physiological and pathological processes of many diseases. Therefore, the development of probes to detect peroxynitrite is important for diagnostic and pathologic studies of many diseases. In this work, a ratiometric probe was designed using benzopyran as the recognition site, and the sensitivity and selectivity of the probe were tuned by modification of substituents on benzopyran. Upon reaction with peroxynitrite, the color of the solution changes to the naked eye (from blue to yellow), and the fluorescence changes from red to blue. The probe SJ has the advantages of large Stokes shift (237 nm), fast response (≤10 s), wide linear range, good selectivity, low detection line (21.3 nm), and low cytotoxicity. Probe SJ has been successfully used for bioimaging of endogenous and exogenous peroxynitrite.


Asunto(s)
Colorantes Fluorescentes , Ácido Peroxinitroso , Espectrometría de Fluorescencia , Ácido Peroxinitroso/análisis , Colorantes Fluorescentes/química , Colorantes Fluorescentes/síntesis química , Humanos , Animales , Benzopiranos/química , Ratones , Límite de Detección
8.
Nano Lett ; 24(20): 6002-6009, 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38739273

RESUMEN

Two-dimensional van der Waals heterostructures (2D-vdWHs) based on transition metal dichalcogenides (TMDs) provide unparalleled control over electronic properties. However, the interlayer coupling is challenged by the interfacial misalignment and defects, which hinders a comprehensive understanding of the intertwined electronic orders, especially superconductivity and charge density wave (CDW). Here, by using pressure to regulate the interlayer coupling of non-centrosymmetric 6R-TaS2 vdWHs, we observe an unprecedented phase diagram in TMDs. This phase diagram encompasses successive suppression of the original CDW states from alternating H-layer and T-layer configurations, the emergence and disappearance of a new CDW-like state, and a double superconducting dome induced by different interlayer coupling effects. These results not only illuminate the crucial role of interlayer coupling in shaping the complex phase diagram of TMD systems but also pave a new avenue for the creation of a novel family of bulk heterostructures with customized 2D properties.

9.
Nat Commun ; 15(1): 3001, 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38589388

RESUMEN

Designing two-dimensional halide perovskites for high-performance optoelectronic applications requires deep understanding of the structure-property relationship that governs their excitonic behaviors. However, a design framework that considers both intra and interlayer structures modified by the A-site and spacer cations, respectively, has not been developed. Here, we use pressure to synergistically tune the intra and interlayer structures and uncover the structural modulations that result in improved optoelectronic performance. Under applied pressure, (BA)2(GA)Pb2I7 exhibits a 72-fold boost of photoluminescence and 10-fold increase of photoconductivity. Based on the observed structural change, we introduce a structural descriptor χ that describes both the intra and interlayer characteristics and establish a general quantitative relationship between χ and photoluminescence quantum yield: smaller χ correlates with minimized trapped excitons and more efficient emission from free excitons. Building on this principle, we design a perovskite (CMA)2(FA)Pb2I7 that exhibits a small χ and an impressive photoluminescence quantum yield of 59.3%.

10.
Foods ; 13(8)2024 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-38672947

RESUMEN

The aim of this study was to investigate the effect of neutral protease treatment on the biochemical properties of various parts of Pacific oysters (Crassostrea gigas) under different storage conditions. The mechanism of quality degradation in the mantle, adductor muscle, gill, and trunk of treated oysters stored at -1.5 °C (superchilling) or 4 °C (refrigeration) for several days using different storage methods was studied. The results showed that the oyster treated with the enzyme exhibited higher glycogen content, flavor nucleotide content, and sensory scores compared to the control group. Superchilling at -1.5 °C was observed to slow the increase in total volatile basic nitrogen (TVB-N), total viable count (TVC), and pH, while maintaining sensory scores better than refrigeration at 4 °C. Both wet superchilling (WS) and dry exposed superchilling (DeS) methods effectively preserved freshness and quality at -1.5 °C. The freshness of the oysters' body trunk changed most significantly. K value, K' value, and AEC value, as the evaluation indexes of oyster freshness, were affected by the storage medium. Therefore, neutral protease enhances the flavor of oysters in a short time, and oysters stored in wet superchilling or dry exposed superchilling conditions have an extended shelf life.

11.
Int J Biol Macromol ; 268(Pt 2): 131787, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38657939

RESUMEN

Chitin oligosaccharides (CTOS) possess potential applications in food, medicine, and agriculture. However, lower mass transfer and catalytic efficiency are the main kinetic limitations for the production of CTOS from shrimp shell waste (SSW) and crystalline chitin. Chemical or physical methods are usually used for pretreatment to improve chitinase hydrolysis efficiency, but this is not eco-friendly and cost-effective. To address this challenge, a chitinase nanoreactor with the liquid-solid system (BcChiA1@ZIF-8) was manufactured to boost the one-step degradation of SSW and crystalline chitin. Compared with free enzyme, the catalytic efficiency of BcChiA1@ZIF-8 on colloidal chitin was significantly improved to 142 %. SSW and crystalline chitin can be directly degraded by BcChiA1@ZIF-8 without any pretreatments. The yield of N, N'-diacetylchitobiose [(GlcNAc)2] from SSW and N-acetyl-D-glucosamine (GlcNAc) from crystalline chitin was 2 times and 3.1 times than that of free enzyme, respectively. The reason was that BcChiA1@ZIF-8 with a liquid-solid system enlarged the interface area, increased the collision frequency between enzyme and substrate, and improved the large-substrates binding activity of chitinase. Moreover, the biphasic system exhibited excellent stability, and the design showed universal applicability. This strategy provided novel guidance for other polysaccharide biosynthesis and the conversion of environmental waste into carbohydrates.


Asunto(s)
Exoesqueleto , Quitina , Quitinasas , Oligosacáridos , Quitina/química , Quitina/metabolismo , Animales , Quitinasas/metabolismo , Quitinasas/química , Oligosacáridos/química , Exoesqueleto/química , Hidrólisis , Reactores Biológicos , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Crustáceos , Cinética , Residuos , Penaeidae/enzimología
12.
Nat Commun ; 15(1): 1467, 2024 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-38368411

RESUMEN

The noncentrosymmetric ferromagnetic Weyl semimetal CeAlSi with simultaneous space-inversion and time-reversal symmetry breaking provides a unique platform for exploring novel topological states. Here, by employing multiple experimental techniques, we demonstrate that ferromagnetism and pressure can serve as efficient parameters to tune the positions of Weyl nodes in CeAlSi. At ambient pressure, a magnetism-facilitated anomalous Hall/Nernst effect (AHE/ANE) is uncovered. Angle-resolved photoemission spectroscopy (ARPES) measurements demonstrated that the Weyl nodes with opposite chirality are moving away from each other upon entering the ferromagnetic phase. Under pressure, by tracing the pressure evolution of AHE and band structure, we demonstrate that pressure could also serve as a pivotal knob to tune the positions of Weyl nodes. Moreover, multiple pressure-induced phase transitions are also revealed. These findings indicate that CeAlSi provides a unique and tunable platform for exploring exotic topological physics and electron correlations, as well as catering to potential applications, such as spintronics.

13.
J Environ Manage ; 353: 120199, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38316072

RESUMEN

Nanofibers were prepared by electrospinning a mixture of polycaprolactone and silica, and modified to improve the hydrophilicity and stability of the material and to degrade nitrogenous wastewater by adsorbing heterotrophic nitrifying aerobic denitrifying (Ochrobactrum anthropic). The immobilized bacteria showed highly efficient simultaneous nitrification-denitrification ability, which could convert nearly 90 % of the initial nitrogen into gaseous nitrogen under aerobic conditions, and the average TN removal rate reached 5.59 mg/L/h. The average ammonia oxidation rate of bacteria immobilized by modified nanofibers was 7.36 mg/L/h, compared with 6.3 mg/L/h for free bacteria and only 4.23 mg/L/h for unmodified nanofiber-immobilized bacteria. Kinetic studies showed that modified nanofiber-immobilized bacteria complied with first-order degradation kinetics, and the effects of extreme pH, temperature, and salinity on immobilized bacteria were significantly reduced, while the degradation rate of free bacteria produced larger fluctuations. In addition, the immobilized bacterial nanofibers were reused five times, and the degradation rate remained stable at more than 80 %. At the same time, the degradation rate can still reach 50 % after 6 months of storage at 4 °C. It also demonstrated good nitrogen removal in practical wastewater treatment.


Asunto(s)
Nanofibras , Aguas Residuales , Desnitrificación , Nitritos/metabolismo , Nitrógeno/metabolismo , Cinética , Aerobiosis , Nitrificación , Bacterias/metabolismo , Procesos Heterotróficos
14.
J Pharm Biomed Anal ; 241: 115998, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38330784

RESUMEN

L-α-glyceryl phosphorylcholine, also referred to as choline ethanol phosphate and phosphocholine glycerophosphate, is a naturally occurring metabolite of water-soluble phospholipids in animals. This molecular property is important for informing the crystallization and purification of drugs. The solubility of L-α-glyceryl phosphorylcholine was determined in ten pure solvents and three mixed solvents under atmospheric pressure. The experimental results indicate that L-α-glyceryl phosphorylcholine is most soluble in methanol and least soluble in acetone. Additionally, the solubility of L-α-glyceryl phosphorylcholine was found to increase with temperature within the experimental range. Furthermore, the solubility of L-α-glyceryl phosphorylcholine in binary solvents is dependent on the proportion of positive solvent and temperature. The solubility of L-α-glyceryl phosphorylcholine increases with the proportion of positive solvent. XRD and DSC results indicate that the crystal form of L-α-glyceryl phosphorylcholine remains unchanged before and after dissolution in the reagent, and its melting point temperature is 413.15 K. Various models, including the modified Apelblat model, λh model, Jouyban-Acree model, SUN model, and CNIBS/R-K model, were used to fit the solubility data of L-α-glyceryl phosphorylcholine in different solvents. The study found that the modified Apelblat model and CNIBS/R-K model were the most appropriate for fitting the data. The KAT-LSER model was used to analyze the molecular interactions between solvents and solutes, revealing that the solvent step method with non-specific polarity/polarization interaction had the greatest impact on solubility.


Asunto(s)
Glicerilfosforilcolina , Fosforilcolina , Solubilidad , Solventes/química , Termodinámica , Agua/química
15.
Food Funct ; 15(3): 1144-1157, 2024 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-38235788

RESUMEN

Iron deficiency anemia (IDA) caused by micronutrient iron deficiency has attracted global attention due to its adverse health effects. The regulation of iron uptake and metabolism is finely controlled by various transporters and hormones in the body. Dietary iron intake and regulation are essential in maintaining human health and iron requirements. The review aims to investigate literature concerning dietary iron intake and systemic regulation. Besides, recent IDA treatment and dietary iron supplementation are discussed. Considering the importance of the gut microbiome, the interaction between bacteria and micronutrient iron in the gut is also a focus of this review. The iron absorption efficiency varies considerably according to iron type and dietary factors. Iron fortification remains the cost-effective strategy, although challenges exist in developing suitable iron fortificants and food vehicles regarding bioavailability and acceptability. Iron deficiency may alter the microbiome structure and promote the growth of pathogenic bacteria in the gut, affecting immune balance and human health.


Asunto(s)
Anemia Ferropénica , Microbioma Gastrointestinal , Deficiencias de Hierro , Oligoelementos , Humanos , Anemia Ferropénica/tratamiento farmacológico , Hierro de la Dieta , Alimentos Fortificados , Hierro , Micronutrientes , Suplementos Dietéticos
16.
J Sci Food Agric ; 104(7): 3947-3957, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38264924

RESUMEN

BACKGROUND: In order to improve the tenderness of dried shrimp products as well as to reduce the hardness of the meat during the drying process, shrimp were treated with ultrasound combined with pineapple protease and the tenderization condition was optimized by measuring the texture and shear force of dried shrimp. In addition, the sulfhydryl content, myofibril fragmentation index (MFI) and microstructure were also examined to clarify the mechanisms of shrimp tenderization. RESULTS: The results showed UB1 group with ultrasonic power of 100 W, heating temperature of 50 °C and pineapple protease concentration of 20 U mL-1 were the optimum tenderization conditions, where shrimp showed the lowest hardness (490.76 g) and shear force (2006.35 gf). Microstructure as well as sodium dodecyl sulfate-polyacrylamide gel electrophoresis results suggested that during the tenderization process the muscle segments of shrimps were broken, degradation of myofibrillar proteins occurred, and MFI values and total sulfhydryl content increased significantly (P < 0.05) (MFI value = 193.6 and total sulfhydryl content = 93.93 mmol mg-1 protein for UB 1 group). CONCLUSION: Ultrasound combined with bromelain could be used as a simple and effective tenderization method for the production of tender dried shrimp. The best conditions were 100 W ultrasonic power, 50 °C ultrasonic temperature, and 20 U mL-1 bromelain. © 2024 Society of Chemical Industry.


Asunto(s)
Ananas , Bromelaínas , Bromelaínas/análisis , Bromelaínas/metabolismo , Alimentos Marinos/análisis , Carne/análisis , Proteínas/metabolismo , Miofibrillas/química
17.
Food Chem ; 438: 138031, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-37995588

RESUMEN

In this study, Polycaprolactone (PCL)/Yam Polysaccharide (YP) fiber membranes loaded the ultrasound-mediated assembly of 2-Hydroxypropyl-ß-cyclodextrin (HP-ß-CD)/Epicatechin gallate (ECG) inclusion complexes were prepared by electrospinning technology for food packaging. Morphology, infrared spectroscopy and X-ray diffraction results showed that the inclusion complexes were successfully assembled. With the addition of inclusion complexes, the average diameter of the fibers increased from 2480.96 to 10179.12 nm, the crystallinity decreased, the thermal stability improved, the hydrophilicity enhanced, and the water vapor permeability enhanced. Meanwhile, thermogravimetry and differential scanning calorimetry results showed that the inclusion complexes formed hydrogen bonds between the fibers, which improved the thermal stability, but the mechanical behavior suffered a certain loss. In addition, the fiber membrane could continuously release ECG within 240 h, which showed excellent antibacterial effects both in vitro and in vivo. These results indicated that the fiber film developed based on electrospinning had a broad application prospect in food packaging.


Asunto(s)
Dioscorea , Nanofibras , 2-Hidroxipropil-beta-Ciclodextrina/química , Nanofibras/química , Embalaje de Alimentos , Difracción de Rayos X , Electrocardiografía , Solubilidad , Rastreo Diferencial de Calorimetría , Espectroscopía Infrarroja por Transformada de Fourier
18.
Food Res Int ; 175: 113758, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38128998

RESUMEN

The objective of this study was to compare the effect of freezing and heating treatment sequences on the biochemical properties and flavor of crab (Portunus trituberculatus) meat during freeze-thaw cycles. The results showed that pH, color, K and microstructure changes in the H-F group were not significant with increasing number of freeze-thaw cycles, but TVB-N values increased and WHC values decreased. However, with the increase in the number of freeze-thaw cycles, pH and WHC significantly decreased and TVB-N, L* and K values significantly increased in the C and F-H groups. Proteins were degraded in all groups, but the lower degree of degradation occurred in the H-F group. Although the total free amino acid content decreased with increasing number of freeze-thaw cycles in each group, the high content of AMP and IMP in the H-F group suggested that it still had a better flavor.


Asunto(s)
Braquiuros , Animales , Congelación , Braquiuros/química , Natación , Calefacción , Carne/análisis
19.
J Agric Food Chem ; 72(1): 857-864, 2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38134022

RESUMEN

Salmonellosis continues to impose a significant economic burden globally. Rapid and sensitive detection of Salmonella is crucial to preventing the outbreaks of foodborne illnesses, yet it remains a formidable challenge. Herein, a dual-functional tetrahedron multivalent aptamer assisted amplification-free CRISPR/Cas12a assay was developed for Salmonella detection. In the system, the aptamer was programmatically assembled on the tetrahedral DNA nanostructure to fabricate a multivalent aptamer (TDN-multiApt), which displayed a 3.5-fold enhanced avidity over the monovalent aptamer and possessed four CRISPR/Cas12a targeting fragments to amplify signal. Therefore, TDN-multiApt could directly activate Cas12a to achieve the second signal amplification without any nucleic acid amplification. By virtue of the synergism of high avidity and cascaded signal amplifications, the proposed method allowed the ultrasensitive detection of Salmonella as low as 7 cfu mL-1. Meanwhile, this novel platform also exhibited excellent specificity against target bacteria and performed well in the detection of various samples, indicating its potential application in real samples.


Asunto(s)
Técnicas Biosensibles , Sistemas CRISPR-Cas , Humanos , Salmonella/genética , Oligonucleótidos , Bioensayo , Brotes de Enfermedades , Técnicas de Amplificación de Ácido Nucleico
20.
Anal Chim Acta ; 1284: 341998, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-37996158

RESUMEN

BACKGROUND: Salmonella infection severely threatens human health and causes substantial medical and financial concerns. Sensitive and specific detection of Salmonella in food samples is crucial but remains challenging. While some traditional assays for S. typhimurium are reliable, they suffer from various limitations, such as being time-consuming (culture-based methods), involving intricate nucleic molecular extraction (polymerization chain reaction, PCR), and exhibiting inadequate sensitivity (enzyme-linked immunosorbent assay, ELISA). In this case, it is essential to establish a rapid, simple-operation, and sensitive method for monitoring S. typhimurium to preserve food quality and prevent contamination. RESULT: Herein, an amplification-free detection method for Salmonella was developed by coupling the aptamer magnetic separation with dual-functional HCR (hybridization chain reaction)-scaffold multivalent aptamer and the activity of CRISPR/Cas12a. In the detection system, the dual-functional HCR-scaffold multivalent aptamer with high binding affinity and specificity was fabricated in advance by assembling numerous Salmonella specific aptamers on the long HCR products. In addition to the enhanced affinity, the HCR-multiApt also contains a massive amount of repeated CRISPR-targetable DNA units in its HCR scaffold, which could trigger the trans-cleavage activity of Cas12a. In the presence of target bacteria, the HCR-scaffold multivalent aptamer could attach on the surface of bacteria effectively and amplified the signal of bacteria into CRISPR/Cas12a based fluorescent readout. The proposed detection system allowed for ultrasensitive detection of Salmonella in a linear range from 100 to 107 cfu mL-1 with a LOD (limit of detection) of 2 cfu mL-1. SIGNIFICANCE: The novel dual-functional HCR-multiApt presents a simple and powerful strategy for improving the aptamer binding affinity toward Salmonella. Simultaneously, integrating this dual-functional HCR-multiApt with the CRISPR/Cas12a system significantly enhances the sensitivity by cascade signal amplification in a nucleic acids amplification-free way. Finally, leveraging the versatility of the aptamer, this highly sensitive method can be further extended for application in the detection of other bacteria, food safety monitoring, or clinical diagnostics.


Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Humanos , Sistemas CRISPR-Cas , Aptámeros de Nucleótidos/genética , Aptámeros de Nucleótidos/química , ADN/química , Hibridación de Ácido Nucleico , Salmonella/genética , Técnicas Biosensibles/métodos
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