A One-Step Chemoenzymatic Labeling Strategy for Probing Sialylated Thomsen–Friedenreich Antigen

Abnormal expression of sialylated Thomsen–Friedenreich antigen (Neu5Acα2-3Galβ1-3GalNAcα-O-Ser/Thr, sialyl-T) has a strong relationship with various types of human cancers and many other diseases. However, the size and structural complexity, and relatively lower abundance of sialyl-T have posed a significant challenge to its detection. Therefore, details about the role of sialyl-T in a variety of physiological and pathological processes are still poorly understood. Here, a one-step chemoenzymatic labeling strategy to probe sialyl-T is described. This approach enables the sensitive, selective, and rapid detection of sialyl-T, and global profiling and identification of unknown sialyl-T-attached glycoproteins, which are potential therapeutic targets or biomarkers. The use of one-step labeling strategy not only has a higher sensitivity than a typical two-step reporter strategy but also avoids undergoing an additional chemical reaction step to introduce a reporter group after the labeling reaction, making it particularly useful for detecting low-abundance glycan epitopes on living cells

A Safe and Facile Route to Imidazole-1-sulfonyl Azide as a Diazotransfer Reagent

A facile approach to the diazotransfer reagent of imidazole-1-sulfonyl azide was reported. The procedure was well optimized to clarify potential explosion risks. A high production yield as well as small batch variation was achieved even without careful pretreatment of reagents and solvents. HPLC and NMR methods to monitor the process were provided. These features made this protocol suitable for large scale preparation in academia and industry as well

Chemoenzymatic Synthesis of a Library of Human Milk Oligosaccharides

Human milk oligosaccharides (HMOs) are a family of diverse unconjugated glycans that exist in human milk as one of the major components. Characterization, quantification, and biofunctional studies of HMOs remain a great challenge due to their diversity and complexity. The accessibility of a homogeneous HMO library is essential to solve these issues which have beset academia for several decades. In this study, an efficient chemoenzymatic strategy, namely core synthesis/enzymatic extension (CSEE), for rapid production of diverse HMOs was reported. On the basis of 3 versatile building blocks, 3 core structures were chemically synthesized via consistent use of oligosaccharyl thioether and oligosaccharyl bromide as glycosylation donors in a convergent fragment coupling strategy. Each of these core structures was then extended to up to 11 HMOs by 4 robust glycosyltransferases. A library of 31 HMOs were chemoenzymatically synthesized and characterized by MS and NMR. CSEE indeed provides a practical approach to harvest structurally defined HMOs for various applications

Multi-locus genotypes of <i>Enterocytozoon bieneusi</i> in captive Asiatic black bears in southwestern China: High genetic diversity, broad host range, and zoonotic potential

<div><p><i>Enterocytozoon bieneusi</i> is an obligate eukaryotic intracellular parasite that infects a wide variety of vertebrate and invertebrate hosts. Although considerable research has been conducted on this organism, relatively little information is available on the occurrence of <i>E</i>. <i>bieneusi</i> in captive Asiatic black bears. The present study was performed to determine the prevalence, genetic diversity, and zoonotic potential of <i>E</i>. <i>bieneusi</i> in captive Asiatic black bears in zoos in southwestern China. Fecal specimens from Asiatic black bears in four zoos, located in four different cities, were collected and analyzed for the prevalence of <i>E</i>. <i>bieneusi</i>. The average prevalence of <i>E</i>. <i>bieneusi</i> was 27.4% (29/106), with the highest prevalence in Guiyang Zoo (36.4%, 16/44). Altogether, five genotypes of <i>E</i>. <i>bieneusi</i> were identified among the 29 <i>E</i>. <i>bieneusi</i>-positive samples, including three known genotypes (CHB1, SC02, and horse2) and two novel genotypes named ABB1 and ABB2. Multi-locus sequence typing using three microsatellites (MS1, MS3, and MS7) and one minisatellite (MS4) revealed V, III, V, and IV genotypes at these four loci, respectively. Phylogenetic analysis showed that the genotypes SC02 and ABB2 were clustered into group 1 of zoonotic potential, the genotypes CHB1 and ABB1 were clustered into a new group, and the genotype horse2 was clustered into group 6 of unclear zoonotic potential. In conclusion, this study identified two novel <i>E</i>. <i>bieneusi</i> genotypes in captive Asiatic black bears, and used microsatellite and minisatellite markers to reveal <i>E</i>. <i>bieneusi</i> genetic diversity. Moreover, our findings show that genotypes SC02 (identified in humans) and ABB2 belong to group 1 with zoonotic potential, suggesting the risk of transmission of <i>E</i>. <i>bieneusi</i> from Asiatic black bears to humans and other animals.</p></div

Prevalence and genotypes of <i>E</i>. <i>bieneusi</i> in Asiatic black bears from zoos in Southwestern China.

<p>Prevalence and genotypes of <i>E</i>. <i>bieneusi</i> in Asiatic black bears from zoos in Southwestern China.</p

Phylogenetic relationship among <i>Enterocytozoon bieneusi</i> groups; the relationship between <i>E</i>. <i>bieneusi</i> genotypes identified in this study and other known genotypes deposited in GenBank was inferred by neighbor-joining analysis of ITS sequences based on genetic distance using the Kimura-2-parameter model.

<p>The numbers on the branches represent percent bootstrapping values from 1,000 replicates, with more than 50% shown in the tree. Each sequence is identified by its accession number, genotype designation, and host origin. Genotypes marked with <i>black triangles</i> and <i>black circles</i> are novel and known genotypes identified in this study, respectively.</p

Multi-locus sequence typing of <i>Enterocytozoon bieneusi</i> in Asiatic black bears in Southwestern China.

<p>Multi-locus sequence typing of <i>Enterocytozoon bieneusi</i> in Asiatic black bears in Southwestern China.</p