Salmonella infection has emerged as a global health threat, causing death, disability, and socioeconomic disruption worldwide. The rapid and sensitive detection of Salmonella is of great significance in guaranteeing food safety. Herein, we developed a colorimetric/fluorescent dual-mode method based on a DNA-nanotriangle programmed multivalent aptamer for the sensitive detection of Salmonella. In this system, aptamers are precisely controlled and assembled on a DNA nanotriangle structure to fabricate a multivalent aptamer (NTri-Multi-Apt) with enhanced binding affinity and specificity toward Salmonella. The NTri-Multi-Apt was designed to carry many streptavidin-HRPs for colorimetric read-outs and a large load of Sybr green I in the dsDNA scaffold for the output of a fluorescent signal. Therefore, combined with the magnetic separation of aptamers and the prefabricated NTri-Multi-Apt, the dual-mode approach achieved simple and sensitive detection, with LODs of 316 and 60 CFU/mL for colorimetric and fluorescent detection, respectively. Notably, the fluorescent mode provided a self-calibrated and fivefold-improved sensitivity over colorimetric detection. Systematic results also revealed that the proposed dual-mode method exhibited high specificity and applicability for milk, egg white, and chicken meat samples, serving as a promising tool for real bacterial sample testing. As a result, the innovative dual-mode detection method showed new insights for the detection of other pathogens.
Biochar, because of its unique physiochemical properties and sorption capacity, may be an ideal amendment in reducing gaseous emissions during composting process but there has been little information on the potential effects of different types of biochar on undesired gaseous emissions. The objective of this study was to examine the ability and mechanism of different types of biochar, as co-substrate, in mitigating gaseous emission from composting of layer hen manure. The study was conducted in small-scale laboratory composters with the addition of 10% of one of the following biochars: cornstalk biochar, bamboo biochar, woody biochar, layer manure biochar and coir biochar. The results showed that the cumulative NH3 production was significantly reduced by 24.8±2.9, 9.2±1.3, 20.1±2.6, 14.2±1.6, 11.8±1.7% (corrected for initial total N) in the cornstalk biochar, bamboo biochar, woody biochar, layer manure biochar and coir biochar treatments, respectively, compared to the control. Total CH4 emissions was significantly reduced by 26.1±2.3, 15.5±2.1, 22.4±3.1, 17.1±2.1% (corrected for the initial total carbon) for cornstalk biochar, bamboo biochar, woody biochar and coir biochar treatments than the control. Moreover, addition of cornstalk biochar increased the temperature and NO3(-)-N concentration and decreased the pH, NH4(+)-N and organic matter content throughout the composting process. The results suggested that total volatilization of NH3 and CH4 in cornstalk biochar treatment was lower than the other treatments; which could be due to (i) decrease of pH and higher nitrification, (ii) high sorption capacity for gases and their precursors, such as ammonium nitrogen from composting mixtures, because of the higher surface area, pore volumes, total acidic functional groups and CEC of cornstalk biochar.
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.
Advanced glycosylation end products (AGEs) are a series of complex compounds which generate in the advanced phase of Maillard reaction, which can pose a non-negligible risk to human health. This article systematically encompasses AGEs in milk and dairy products under different processing conditions, influencing factors, inhibition mechanism and levels among the different categories of dairy products. In particular, it describes the effects of various sterilization techniques on the Maillard reaction. Different processing techniques have a significant effect on AGEs content. In addition, it clearly articulates the determination methods of AGEs and even discusses its immunometabolism via gut microbiota. It is observed that the metabolism of AGEs can affect the composition of the gut microbiota, which further has an impact on intestinal function and the gut-brain axis. This research also provides a suggestion for AGEs mitigation strategies, which are beneficial to optimize the dairy production, especially innovative processing technology application.
Gelatin has played a great potential in food preservation because of its low price and superior film forming characteristics. This review provides a comprehensive overview of the latest research progress and application of gelatin preservation technologies (film, coating, antifreeze peptide, etc.), discussing their preservation mechanisms and efficiency through the viewpoints of quality and shelf life of animal and aquatic products as well as fruits and vegetables. It showed that bioactive and intelligent gelatin-based films exhibit antibacterial, antioxidant, water resistance and pH responsive properties, making them excellent for food preservation. In addition, pH responsive properties of films also intuitively reflect the freshness of food by color. Similarly, gelatin and its hydrolysate can be widely used in antifreeze peptides to reduce the mass loss of food during freezing and extend the shelf life of frozen food. However, extensive works are still required to extend their commercial application values.
Soft actuators offer numerous potential applications; however, challenges persist in achieving a high driving force and fast response speed. In this work, we present the design, fabrication, and analysis of a soft pneumatic bistable actuator (PBA) mimicking jellyfish subumbrellar muscle motion for waterjet propulsion. Drawing inspiration from the jellyfish jet propulsion and the characteristics of bistable structure, we develop an elastic band stretch prebending PBA with a simple structure, low inflation cost, exceptional driving performance, and stable driving force output. Through a bionic analysis of jellyfish body structure and motion, we integrate the PBA into a jellyfish-like prototype, enabling it to achieve jet propulsion. To enhance the swimming performance, we introduce a skin-like structure for connecting the soft actuator to the jellyfish-like soft robot prototype. This skin-like structure optimizes the fluid dynamics during jet propulsion, resulting in improved efficiency and maneuverability. Our study further analyzes the swimming performance of the jellyfish-like prototype, demonstrating a swimming speed of 3.8 cm/s (0.32 body length/s, BL/s) for the tethered prototype and 4.7 cm/s (0.38 BL/s) for the untethered prototype. Moreover, we showcase the jellyfish-like prototype's notable load-bearing capacity and fast-forward swimming performance compared to other driving methods for underwater biomimetic robots. This work provides valuable insights for the development of highly agile and fast responsive soft robots that imitate the subumbrellar muscle of jellyfish for efficient water-jet propulsion, utilizing skin-like structures to enhance swimming performance.
Chicken plasma protein hydrolysate (CPPH) was prepared by trypsin with angiotensin I-converting enzyme (ACE) inhibitory activity of 53.5% ± 0.14% and the degree of hydrolysis (DH) of 16.22% ± 0.21% at 1 mg·ml-1; then, five proteases, including pepsin, trypsin, papain, alcalase, and neutrase, were employed to improve ACE inhibitory ability by catalyzing plastein reaction. The results indicated that trypsin-catalyzed plastein reaction showed the highest ACE inhibitory activity. The exogenous amino acids of leucine, histidine, tyrosine, valine, and cysteine were selected to modify the CPPH. The leucine-modified plastein reaction released the highest ACE inhibitory activity. The effects of four reaction parameters on plastein reaction were studied, and the optimal conditions with the purpose of obtaining the most powerful ACE inhibitory peptides from modified products were obtained by response surface methodology (RSM). The maximum ACE inhibition rate of the modified hydrolysate reached 82.07% ± 0.03% prepared at concentration of hydrolysates of 30%, reaction time of 4.9 hr, pH value of 8.0, temperature of 40°C, and E/S ratio of 5,681.62 U·g-1. The results indicated that trypsin-catalyzed plastein reaction increased ACE inhibitory activity of chicken plasma protein hydrolysates by 28.57%.