Identification of the Microbial Transformation Products of Secoisolariciresinol Using an Untargeted Metabolomics Approach and Evaluation of the Osteogenic Activities of the Metabolites.

Secoisolariciresinol (SECO) is one of the major lignans occurring in various grains, seeds, fruits, and vegetables. The gut microbiota plays an important role in the biotransformation of dietary lignans into enterolignans, which might exhibit more potent bioactivities than the precursor lignans. This study aimed to identify, synthesize, and evaluate the microbial metabolites of SECO and to develop efficient lead compounds from the metabolites for the treatment of osteoporosis.

Structural characteristics and fermentation patterns of polysaccharides from mushrooms.

The aim of this study was to investigate the structural characteristics and fermentation patterns of polysaccharides from mushrooms. Polysaccharides were solubilized from fruit bodies of selected mushrooms , , and using subcritical water extraction. polysaccharides were characterized for their general physicochemical pattern, constituent monosaccharides and molecular weight.

Preliminary Findings of the High Quantity of Microplastics in Faeces of Hong Kong Residents.

Microplastics are recognised as a ubiquitous and hazardous pollutant worldwide. These small-sized particles have been detected in human faeces collected from a number of cities, providing evidence of human ingestion of microplastics and their presence in the gastrointestinal tract. Here, using Raman spectroscopy, we identified an average of 50 particles g (20.

Influence of pH-responsive compounds synthesized from chitosan and hyaluronic acid on dual-responsive (pH/temperature) hydrogel drug delivery systems of Cortex Moutan.

The polysaccharide-based pH-responsive compounds, namely, N,N,N-trimethyl chitosan (TMC), polyethylene glycolated hyaluronic acid (PEG-HA), and polysaccharide-based nano-conjugate of hyaluronic acid, chitosan oligosaccharide and alanine [HA-Ala-Chito(oligo)] were chemically synthesized using biopolymers chitosan and hyaluronic acid, and applied here to observe the changes in morphology, pH-stability, mechanical and drug-release behavior, and cytotoxicity of thermo-responsive polymer: Poloxamer 407 (PF127)-based drug delivery systems for traditional Chinese medicine Cortex Moutan (CM). The thermo-responsive hydrogel of PF127 loaded with CM (Gel) was used as control. The dual-responsive (pH/temperature) hydrogels: PF127/TMC/PEG-HA (Gel) and PF127/HA-Ala-Chito(oligo) (Gel) showed improved mechanical behavior as obtained by rheology and mechanical agitation study, and pH-stability under various external pH conditions, and those improvements occurred due to the addition of polysaccharide-based pH-responsive compounds in the systems.

Mechanistic insights into the structure-dependant and strain-specific utilization of wheat arabinoxylan by Bifidobacterium longum.

Arabinoxylan (AX), an important dietary fiber from cereal grains, is mainly metabolised in the large intestine by gut bacteria, especially bifidobacteria. This study investigated the uptake and metabolism of wheat AX by a Bifidobacterium longum strain that could grow well with AX as the sole carbon source. The bacterial growth rate showed a significant correlation to the molecular weight (MW) of AX and its acid hydrolysates.

Reusable Face Masks as Alternative for Disposable Medical Masks: Factors that Affect their Wear-Comfort.

The coronavirus outbreak that commenced at the end of 2019 has led to a dramatic increase in the demand for face masks. In countries that are experiencing a shortage of face masks as a result of panic buying or inadequate supply, reusable fabric masks have become a popular option, because they are often considered more cost-effective and environmentally friendly than disposable medical masks. Nevertheless, there remains a significant variation in the quality and performance of existing face masks; not all are simultaneously able to provide protection against the extremely contagious virus and be comfortable to wear.

Shiga toxin 1 is more dependent on the P proteins of the ribosomal stalk for depurination activity than Shiga toxin 2.

Shiga toxins produced by Escherichia coli O157:H7 are responsible for food poisoning and hemolytic uremic syndrome (HUS). The A subunits of Shiga toxins (Stx1A and Stx2A) inhibit translation by depurinating a specific adenine in the large rRNA. To determine if Stx1A and Stx2A require the ribosomal stalk for depurination, their activity and cytotoxicity were examined in the yeast P protein deletion mutants.

A two-step binding model proposed for the electrostatic interactions of ricin a chain with ribosomes.

Ricin is a ribosome inactivating protein that catalytically removes a universally conserved adenine from the alpha-sarcin/ricin loop (SRL) of the 28S rRNA. We recently showed that ricin A chain (RTA) interacts with the P1 and P2 proteins of the ribosomal stalk to depurinate the SRL in yeast. Here we examined the interaction of RTA with wild-type and mutant yeast ribosomes deleted in the stalk proteins by surface plasmon resonance.

The ribosomal stalk is required for ribosome binding, depurination of the rRNA and cytotoxicity of ricin A chain in Saccharomyces cerevisiae.

Ribosome inactivating proteins (RIPs) like ricin, pokeweed antiviral protein (PAP) and Shiga-like toxins 1 and 2 (Stx1 and Stx2) share the same substrate, the alpha-sarcin/ricin loop, but differ in their specificities towards prokaryotic and eukaryotic ribosomes. Ricin depurinates the eukaryotic ribosomes more efficiently than the prokaryotic ribosomes, while PAP can depurinate both types of ribosomes. Accumulating evidence suggests that different docking sites on the ribosome might be used by different RIPs, providing a basis for understanding the mechanism underlying their kingdom specificity.