Chaoxin Man

Sialic acid (SA) is a naturally occurring derivative of nine-carbon monosaccharides that are typically present as oligosaccharides, glycoproteins, or glycolipids in the blood during pregnancy and in breast milk. Hepatic synthesis of SA occurs from the fetal period to 6 months after birth; therefore, exogenous SA is essential for early life growth and development. This review examines the nutritional requirements for various forms of SA in early life, considering its content in the maternal serum, breast milk, and supplementary infant foods. Additionally, it examines the synthesis and metabolism of SA, its roles in the brain and intestinal development, immune system maturation, and its efficacy in preventing and managing preterm birth and related conditions. Finally, it highlights crucial research in SA nutrition in early life to provide a scientific basis for the use of SA in infant formulas, maternal food, and medical settings.

Salmonella typhimurium (S. typhimurium) is one of the major foodborne pathogenic bacteria, posing a serious threat to human health and food safety. The sensitive and reliable S. typhimurium detection methods are crucial for preventing disease outbreaks and ensuring food safety. Recently, Argonaute proteins have emerged as a highly effective tool for pathogenic bacteria detection owing to their programmability and exceptional specificity. In this study, we developed a novel label-free fluorescent biosensing platform by innovatively integrating Pyrococcus furiosus Argonaute (PfAgo) with programmable Aurora DNAzyme for sensitive detection of S. typhimurium. Specifically, a label-free signaling probe (engineered-Aurora, E-Aurora) was designed by introducing the target sequence into the catalytic core sequence of Aurora DNAzyme. The E-Aurora could bind to the 4-methylumbelliferyl phosphate (4-MUP) and transfer its phosphoryl group to its own 5'-OH terminus, thereby generating the strong fluorescent compound 4-MU. In this biosensing platform, the PfAgo could be activated by S. typhimurium and was able to cleave the E-Aurora, thereby destroying the structural integrity of E-Aurora. The fragmentary E-Aurora was incapable of catalyzing 4-MUP to generate fluorescent signals. The concentration of S. typhimurium was inversely proportional to the fluorescent signal. Benefiting from the specific recognition and cleavage ability of PfAgo and the outstanding catalytic ability of E-Aurora, the established biosensor achieved high sensitivity for S. typhimurium with a limit of detection as low as 1 CFU/mL. This work provided a new insight for designing a novel label-free PfAgo-based fluorescence biosensor for the detection of pathogenic bacteria.

Programmable CRISPR/Cas12a has emerged as a promising and powerful tool for the construction of biosensors, yet the challenges persist regarding the signal transduction efficiency, sensitivity, and multisignal outputs. In this work, a metal-organic framework (MOF) nanozyme with an aggregation-induced emission (AIE) property and peroxidase (POD)-like activity was synthesized by encapsulating hemin into a Zr-based MOF using an in situ encapsulation strategy, named AIE MOFzyme. The prepared AIE MOFzyme showed an enhanced fluorescent property via the restriction of the intramolecular motion effect for boosting the significant fluorescent response and a highly efficient POD-like nanozyme activity for activating visual colorimetric response. Benefiting from these merits, AIE MOFzyme, as a difunctional signal probe, was embedded into a DNA hydrogel for the construction of a CRISPR-responsive AIE MOFzyme hydrogel platform (abbreviated as Cas12a-H-AIE). In this platform, the activated CRISPR/Cas12a system led to DNA hydrogel phase transitions to release AIE MOFzymes, triggering highly efficient fluorescent and colorimetric signal amplification. Importantly, the CRISPR-responsive AIE MOFzyme hydrogel platform for the detection of Salmonella enterica (S. enterica) showed a high sensitivity, which was superior to that of numerous existing methods. This work provided new insight for the design of multifunctional and programmable nanozyme hydrogels, which may also offer guidance for the development of novel CRISPR/Cas12a-based biosensors.

Background/Objectives: Disorders of glucose and lipid metabolism can easily lead to metabolic diseases such as hyperlipidemia and diabetes mellitus, with multiple complications. This study evaluated the regulatory effect of purple-grain wheat on glycolipid metabolism. Methods: In this study, we established a hyperlipidemic mouse model by means of a high-fat diet and a type 2 diabetic mouse model using a high-fat and high-sugar diet combined with streptozotocin, and the mice were intervened with 15 g/(kg·d), 7.5 g/(kg·d), and 3.75 g/(kg·d) doses of purple-grain wheat paste (PWP) for 4 and 5 weeks, respectively. Results: The results revealed that PWP reversed the increase in body weight; increased serum high-density lipoprotein cholesterol; and decreased serum total cholesterol, triglycerides, and low-density lipoproteins. In addition, PWP reversed the decrease in body weight and alleviated the sustained increase in blood glucose in type 2 diabetic mice. Conclusions: PWP shows a significant ability to regulate glycolipid levels, which is related to its functional composition and its ability to act as a prebiotic. In conclusion, PWP can be considered a potential functional food for lowering blood glucose and blood lipids.

Fermented milk has a long history. It is fermented by lactic acid bacteria and is rich in protein, minerals, vitamins, and other nutrients. As people’s pursuit of quality of life improves, consumers are paying increasing attention to fermented milk. Streptococcus salivarius ssp. thermophilus is commonly used to make fermented milk. This study investigated the fermentation characteristics and physicochemical properties of Streptococcus salivarius ssp. thermophilus Snew-fermented milk, as well as transcriptomic and metabolomic analyses of different fermentation stages. Streptococcus salivarius ssp. thermophilus Snew can be used as a fermenter strain, as evaluated from the point of view of fermentation time, titratable acidity, post-acidification, viable bacteria count, water holding capacity, and viscosity. The flavor and odor of Snew-fermented milk varied across fermentation stages. The analysis of the detected volatiles revealed that ketones and esters were the main substances responsible for the flavor of Snew-fermented milk. The differentially expressed genes and differential metabolites screened from several categories, such as carbohydrates, proteins, amino acids, fats, and fatty acids, varied at different fermentation stages, while differentially expressed genes and differential metabolites were also threaded together for joint analysis in this study. This study provides theoretical guidance for the practical production application of Streptococcus salivarius ssp. thermophilus in cow’s milk fermentation.