Identifying glycan consumers in human gut microbiota samples using metabolic labeling coupled with fluorescence-activated cell sorting

The general glycan profiling of Dendrobium officinale and their protective effects on MIN6 cells via ERK signaling pathway

Based on structural elucidation of natural and hydrolyzed glycans, the general glycans profiling of D. officinale were unequivocally established for the first time as follows: The results indicated that the structure of D. officinale glycans with low degree of polymerization (DP ≤ 22) was linear α-D-1,4-glucan, whereas the structure of glycans with high degree of polymerization (DP > 24) was linear acetylated 1,4-glucomannan. The content of acetyl groups and mannose to glucose (M/G) ratio increased with the degree of polymerization of D. officinale glycans. In addition, this study showed that natural D. officinale glycans protected pancreatic β-cell damage induced by glucotoxicity through the extracellular signal-regulated kinase (ERK)1/2 pathway.

The Impact of Surface Modifier on Magnetic Nanoparticle Properties and Their Application in CD3+T Cell Separation

Fe3O4 nanoparticles occupy a pivotal position in the realm of nanobiology due to their nontoxic, biocompatible, and superparamagnetic properties. This study examines the influence of surface modifiers on the properties of magnetic nanoparticles. Poly(methacrylic acid) (PMAA), poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSM), trisodium citrate (TSC), carboxymethylcellulose (CMC), and carboxymethylated-dextran 40 (CMD40) were introduced into a one-pot solvothermal method to synthesize magnetic nanoparticles. TEM, the 4-(bromomethyl)-6,7-dimethoxy coumarin (BMMC) absorption assay, and the Bradford method were employed to characterize the diameter, carboxyl content, and protein immobilization ability of the nanoparticles, respectively. The findings revealed that CMD40-modified magnetic nanoparticles (CMD40-MNPs) exhibited the highest carboxyl content and streptavidin (SA) immobilization content, reaching 6.5 × 10-7 mol/mg and 375 μg/mg, respectively. In contrast, CMC-modified magnetic nanoparticles displayed opposite trends. This is primarily attributed to dextran's unique molecular structure, which enhances its water solubility and biocompatibility, thereby facilitating contact with Fe3O4 nanoparticles in aqueous solutions. CMD40-MNPs possess a saturation magnetization value of 60.90 emu/g and can be collected within (60 ± 5) s using a standard magnetic separator. Cytotoxicity assays demonstrated that CMD40-MNPs are nontoxic to cells. A cell sorting strategy utilizing the binding of SA-CMD40-MNPs and biotin antihuman CD3 antibody-modified cell suspensions was employed to isolate CD3+T cells. The results indicate that the purity and efficiency of targeted CD3+T cells are 85.2% and 61.5%, respectively.

Industrial Research and Development on the Production Process and Quality of Cultured Meat Hold Significant Value: A Review

Cultured meat has been gaining popularity as a solution to the increasing problem of food insecurity. Although research on cultured meat started later compared to other alternative meats, the industry is growing rapidly every year, with developed products evaluated as being most similar to conventional meat. Studies on cultured meat production techniques, such as culturing new animal cells and developing medium sera and scaffolds, are being conducted intensively and diversely. However, active in-depth research on the quality characteristics of cultured meat, including studies on the sensory and storage properties that directly influence consumer preferences, is still lacking. Additionally, studies on the combination or ratio of fat cells to muscle cells and on the improvement of microbiota, protein degradation, and fatty acid degradation remain to be conducted. By actively investigating these research topics, we aim to verify the quality and safety of cultured meats, ultimately improving the consumer preference for cultured meat products.

Recent Progress in Human Milk Oligosaccharides and Its Antiviral Efficacy

Gastrointestinal (GI)-associated viruses, including rotavirus (RV), norovirus (NV), and enterovirus, usually invade host cells, transmit, and mutate their genetic information, resulting in influenza-like symptoms, acute gastroenteritis, encephalitis, or even death. The unique structures of human milk oligosaccharides (HMOs) enable them to shape the gut microbial diversity and endogenous immune system of human infants. Growing evidence suggests that HMOs can enhance host resistance to GI-associated viruses but without a systematic summary to review the mechanism. The present review examines the lactose- and neutral-core HMOs and their antiviral effects in the host. The potential negative impacts of enterovirus 71 (EV-A71) and other GI viruses on children are extensive and include neurological sequelae, neurodevelopmental retardation, and cognitive decline. However, the differences in the binding affinity of HMOs for GI viruses are vast. Hence, elucidating the mechanisms and positive effects of HMOs against different viruses may facilitate the development of novel HMO derived oligosaccharides.

Characterizing the Effect of Amylase Inhibitors on Maltodextrin Metabolism by Gut Bacteria Using Fluorescent Glycan Labeling

Diet-derived polysaccharides are an important carbon source for gut bacteria and shape the human gut microbiome. Acarbose, a compound used clinically to treat type 2 diabetes, is known to inhibit the growth of some bacteria on starches based on its activity as an inhibitor of α-glucosidases and α-amylases. In contrast to acarbose, montbretin A, a new drug candidate for the treatment of type 2 diabetes, has been reported to be more specific for the inhibition of α-amylase, notably human pancreatic α-amylase. However, the effects of both molecules on glycan metabolism across a larger diversity of human gut bacteria remain to be characterized. Here, we used ex vivo metabolic labeling of a human microbiota sample with fluorescent maltodextrin to identify gut bacteria affected by amylase inhibitors. Metabolic labeling was performed in the presence and absence of amylase inhibitors, and the fluorescently labeled bacteria were identified by fluorescence-activated cell sorting coupled with 16S rDNA amplicon sequencing. We validated the labeling results in cultured isolates and identified four gut bacteria species whose metabolism of maltodextrin is inhibited by acarbose. In contrast, montbretin A slowed the growth of only one species, supporting the fact that it is more selective. Metabolic labeling is a valuable tool to characterize glycan metabolism in microbiota samples and could help understand the untargeted impact of drugs on the human gut microbiota.