Figure - available from: Sensors and Diagnostics
This content is subject to copyright. Terms and conditions apply.
Source publication
![[A] Generic molecular structure of Sia. [B] Molecular structures of...](publication/356537614/figure/fig1/AS:11431281158591929@1684164437700/A-Generic-molecular-structure-of-Sia-B-Molecular-structures-of-common-Sia_Q320.jpg)
![Negative charge of Neu5Ac in [A] dispersion of RBC in blood and [B]...](publication/356537614/figure/fig2/AS:11431281158621900@1684164439844/Negative-charge-of-Neu5Ac-in-A-dispersion-of-RBC-in-blood-and-B-glomerular-filtration_Q320.jpg)
![[A] A pictorial configuration of the main constituents of the spike...](publication/356537614/figure/fig3/AS:11431281158601921@1684164443329/A-A-pictorial-configuration-of-the-main-constituents-of-the-spike-protein-of-SARS-CoV-2_Q320.jpg)
Sialic acid (Sia) is widely distributed in free, polymeric and conjugated forms in living creatures and humans. It serves various roles in human physiology including brain development, function of central nervous system, the immune system, lactation and infant cognition. Sia is over- or under-expressed in human cells, tissues and fluids during phys...
Citations
... They widely occur in vertebrates and higher invertebrates as terminal components of glycans on the cell-surface glycoconjugates [2]. To date, over 90 naturally occurring forms of Sia have been identified [3,4]. The high structural complexity and diverse properties of Sia contribute to a variety of biological functions, including antiviral activity [3], immunomodulatory activity [5], beneficial effects on brain and cognitive function [6], and skin whitening [7]. ...
... To date, over 90 naturally occurring forms of Sia have been identified [3,4]. The high structural complexity and diverse properties of Sia contribute to a variety of biological functions, including antiviral activity [3], immunomodulatory activity [5], beneficial effects on brain and cognitive function [6], and skin whitening [7]. N-acetylneuraminic acid (Neu5Ac), systematically named 5-acetamido-3,5-dideoxy-D-glycero-D-galacto-non-2-ulopyranosonic acid, is the dominant type of Sia [8,9]. ...
... Later in 2017, European Food Safety Authority (EFSA) certified synthetic Neu5Ac as a novel food (NF) with regulation No. 258/97. Following this regulation, the European Commission approved Neu5Ac for use as a food additive in the market at the prescribed amounts [3]. In addition, Neu5Ac has also been approved by China as a new food ingredient. ...
N-Acetylneuraminic acid (Neu5Ac), the most common type of Sia, generally acts as the terminal sugar in cell surface glycans, glycoconjugates, oligosaccharides, lipo-oligosaccharides, and polysaccharides, thus exerting numerous physiological functions. The extensive applications of Neu5Ac in the food, cosmetic, and pharmaceutical industries make large-scale production of this chemical desirable. Biosynthesis which is associated with important application potential and environmental friendliness has become an indispensable approach for large-scale synthesis of Neu5Ac. In this review, the physiological roles of Neu5Ac was first summarized in detail. Second, the safety evaluation, regulatory status, and applications of Neu5Ac were discussed. Third, enzyme-catalyzed preparation, whole-cell biocatalysis, and microbial de novo synthesis of Neu5Ac were comprehensively reviewed. In addition, we discussed the main challenges of Neu5Ac de novo biosynthesis, such as screening and engineering of key enzymes, identifying exporters of intermediates and Neu5Ac, and balancing cell growth and biosynthesis. The corresponding strategies and systematic strategies were proposed to overcome these challenges and facilitate Neu5Ac industrial-scale production.
... All vertebrate cells are covered by a glycocalyx, a dense layer of glycoproteins and glycolipids, in which the distal parts of the glycans are often terminated by a non-reducing α-linked sialic acid unit [1][2][3]. Sialic acids (Sias) belong to a family of many differently substituted neuraminic acids. In humans, N-acetylneuraminic acid (Neu5Ac) is the most predominant Sia. ...
... Although Neu5Gc is absent in healthy human cells, high levels of it have been observed in various cancers (ovarian, breast, colon, lung, and prostate) [2,23]. Diseases may also be reflected in abnormal levels of free Neu5Ac in serum, which has been demonstrated for several types of cancer, rheumatoid arthritis, cirrhosis, Crohn's disease, type 2 diabetes, and alcohol abuse [2,21,[24][25][26][27][28][29][30]. ...
... Although Neu5Gc is absent in healthy human cells, high levels of it have been observed in various cancers (ovarian, breast, colon, lung, and prostate) [2,23]. Diseases may also be reflected in abnormal levels of free Neu5Ac in serum, which has been demonstrated for several types of cancer, rheumatoid arthritis, cirrhosis, Crohn's disease, type 2 diabetes, and alcohol abuse [2,21,[24][25][26][27][28][29][30]. The blood-circulating glycoprotein fetuin also has a terminal Neu5Ac group and abnormal levels of fetuin are indicative of various diseases [31]. ...
In this review, the chemical mechanisms behind the interactions between boronic acids and N-neuraminic acids, which have been widely utilized in biomedicine in recent decades, will be examined. It will also be highlighted that the affinity of boronic acids for N-neuraminic acids is dependent on pH and is complementary to their affinity for other common monosaccharides found in glycocalyces. Through various examples from the literature, the unique pH profile of the boronic - N-neuraminic acids acid interaction and its uses in biomedicine will be illustrated.
... It is also used in the routine detection of small molecular pollutants such as antibiotics and veterinary drugs, which are often enriched in egg white [20]. Studies have found that viscous polysaccharides (mannose, mucin, and albumin) that are present in viscous proteins (such as ovalbumin and albumin) are enriched in the small and medium molecules present in egg white [21][22][23][24]. Suppose egg white can be used as an effective matrix-purifying material. ...
The analysis of food samples is a challenging task. The high complexity of food matrices hinders the extraction and detection of analytes from them. Therefore, the correct preparation of food samples is a crucial step for their subsequent analysis, as it achieves the proper isolation and preconcentration of analytes and removes the interfering proportion of the food matrix before instrumental analysis. We aimed to develop a method that not only satisfies the requirement of detecting trace compounds in complex matrices but also achieves a “greener” approach by reducing the use of organic solvents and non-degradable materials to minimize the health hazards posed to the operators as well as pollution to the environment. In this study, we prepared egg white as a concentrated gel and used this material for the biological purification of milk samples. After the milk protein was removed by acidification and salting, the residual amount of aflatoxin M1 in milk samples was quantitatively determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The results showed that the novel egg white purification method possessed advantages over the immunoaffinity technique used as the reference method in extraction recovery, sensitivity, repeatability, and operability. The limit of detection (LOD) was 0.001 μg/kg. In spiked samples containing 0.01 μg/kg to 2 μg/kg of AFM1, the average recovery was 88.3–94.7%, with a precision of 6.1–11.0%. Improved repeatability was obtained by significantly reducing the operation time and resource requirements compared with the immunoaffinity technique currently used internationally. This study provides a reference for the further improvement of the relevant international standards in place for the detection of aflatoxin M1 in milk.
An electrochemical sensor of SARS-CoV-2 spike glycoprotein S1 has been developed using N-acetyl neuraminic acid (Neu5Ac) as the biosensing agent based on the interaction between Neu5Ac with the N-terminal domain of spike glycoprotein S1. Gold-modified screen-printed carbon electrode (Au-SPCE), prepared by electrochemical deposition of gold particles on the screen-printed carbon electrode surface, was used to detect the presence of the SARS-CoV-2 from the change of electrochemical behavior of Neu5Ac. Cyclic voltammetry of Neu5Ac in phosphate buffer solution pH 7.6 at Au-SPCE electrodes observes a couple of oxidation and reduction peaks at the potentials of +0.6 and 0.1 V (vs. Ag/AgCl), respectively. The currents of both peaks linearly increased with the NAeu5Ac concentrations in the range from 0 to 200 µM. The sensitivity of 0.77 mA/mM and 0.47 mA/mM for reduction and oxidation currents were observed, respectively, with the estimated detection limits (LODs) of 51.05 µM and 35.77 µM. In the presence of SARS-CoV-2 spike glycoprotein S1 these current peaks decreased. At an optimum contact time of 30 min, a linear correlation to the current changes of the reduction peaks was observed in the spike glycoprotein S1 with the concentration ranges from 0 to 0.01 µg/ml. The estimated LOD of 0.7 ng/ml could be achieved with excellent stability (2.18% RSD value for n = 10), indicating the developed sensor is promising to be utilized in real applications of SARS-CoV-2 spike glycoprotein S1 detection.
Sialic acid (SA) is a naturally occurring monosaccharide found in glycoproteins and glycolipids. Changes in the expression of SA are associated with several diseases; thus, the detection of SA is...
Sialic acids (SAs) are α-keto-acid sugars with a nine-carbon backbone present at the non-reducing end of human milk oligosaccharides and the glycan moiety of glycoconjugates. SAs displayed on cell surfaces participate in the regulation of many physiologically important cellular and molecular processes, including signaling and adhesion. Additionally, sialyl-oligosaccharides from human milk act as prebiotics in the colon by promoting the settling and proliferation of specific bacteria with SA metabolism capabilities. Sialidases are glycosyl hydrolases that release α-2,3-, α-2,6- and α-2,8-glycosidic linkages of terminal SA residues from oligosaccharides, glycoproteins and glycolipids. The research on sialidases has been traditionally focused on pathogenic microorganisms, where these enzymes are considered virulence factors. There is now a growing interest in sialidases from commensal and probiotic bacteria and their potential transglycosylation activity for the production of functional mimics of human milk oligosaccharides to complement infant formulas. This review provides an overview of exo-alpha-sialidases of bacteria present in the human gastrointestinal tract and some insights into their biological role and biotechnological applications.
Sialic acid (SA) is an acidic monosaccharide present in the human brain and body fluids in the form of N-acetylneuraminic acid. It is also a well-known cancer biomarker. For decades, it has remained a challenging task to design synthetic receptors for SA. However, mainly because of the interference from other sugars with the receptors, it was challenging to differentiate SA from other sugars. Here, we report the development of a two-component aggregation-induced emissive (AIE) probes that can interact with SA and other saccharides via noncovalent interactions with unique emission fingerprints. Analysis of the output signals enabled the reliable detection and clear discrimination of SA in the presence of other saccharides with high accuracy. Further, its potential application in cellular glycan mapping has been explored by fluorescence imaging and surface-enhanced Raman scattering with MDA-MB-231 breast cancer cells.
Food allergies (FA), a major public health problem recognized by the World Health Organization, affect an estimated 3%–10% of adults and 8% of children worldwide. However, effective treatments for FA are still lacking. Recent advances in glycoimmunology have demonstrated the great potential of sialic acids (SAs) in the treatment of FA. SAs are a group of nine-carbon α-ketoacids usually linked to glycoproteins and glycolipids as terminal glycans. They play an essential role in modulating immune responses and may be an effective target for FA intervention. As exogenous food components, sialylated polysaccharides have anti-FA effects. In contrast, as endogenous components, SAs on immunoglobulin E and immune cell surfaces contribute to the pathogenesis of FA. Given the lack of comprehensive information on the effects of SAs on FA, we reviewed the roles of endogenous and exogenous SAs in the pathogenesis and treatment of FA. In addition, we considered the structure–function relationship of SAs to provide a theoretical basis for the development of SA-based FA treatments.
