Beta-Glucans from Fungi: Biological and Health-Promoting Potential in the COVID-19 Pandemic Era

Beta-glucans comprise a group of polysaccharides of natural origin found in bacteria, algae, and plants, e.g., cereal seeds, as well as microfungi and macrofungi (mushrooms), which are characterized by diverse structures and functions. They are known for their metabolic and immunomodulatory properties, including anticancer, antibacterial, and antiviral. Recent reports suggest a potential of beta-glucans in the prevention and treatment of COVID-19. In contrast to β-glucans from other sources, β-glucans from mushrooms are characterized by β-1,3-glucans with short β-1,6-side chains. This structure is recognized by receptors located on the surface of immune cells; thus, mushroom β-glucans have specific immunomodulatory properties and gained BRM (biological response modifier) status. Moreover, mushroom beta-glucans also owe their properties to the formation of triple helix conformation, which is one of the key factors influencing the bioactivity of mushroom beta-glucans. This review summarizes the latest findings on biological and health-promoting potential of mushroom beta-glucans for the treatment of civilization and viral diseases, with particular emphasis on COVID-19.

Comparison of Native and Regenerated Antheraea Pernyi Silk Fibroin

The regenerated Antheraea pernyi silk fibroin (RASF) was harvested by dissolving the silk fibers in a calcium nitrate solution. XRD result demonstrated that both native and regenerated Antheraea pernyi silk fibroin involved the α-helix conformation, and DTG curves showed that their thermal decompositions were quite similar and proceeded three steps. However, rheological measurements figured out that the molecule weight of RASF decreased from 246 kDa to 199 kDa, comparing with native Antheraea pernyi silk fibroin. Also, the tensile properties of the RASF film, which were the same to those of regenerated Bombyx mori silk fibroin film, were observed.

Interactions of a multifunctional di-triazole derivative with Alzheimer's Aβ42 monomer and Aβ42 protofibril: a systematic molecular dynamics study

The molecular dynamics simulations results highlighted that the multi-target-directed ligand 6n stabilizes the native α-helix conformation of the Aβ42 monomer and induces a sizable destabilization in the Aβ42 protofibril structure.

Conformational Preferences of Aβ25-35 and Aβ35-25 in Membrane Mimicking Environments

Background: The structural transition of aggregating Abeta peptides is the key event in the progression of Alzheimer’s Disease (AD). Objective: In the present work, the structural modifications of toxic Aβ25-35 and the scrambled Aβ35-25 were studied in Trifluoroethanol (TFE) and in aqueous SDS micelles. Methods: Using CD spectroscopic investigations, the conformational transition of Aβ25-35 and Aβ35-25 peptides were determined in different membrane mimicking environments such as TFE and SDS. An interval scan CD of the peptides on evaporation of TFE was performed. TFE titrations were carried out to investigate the intrinsic ability of the structural conformations of peptides. Results: We show by spectroscopic evidence that Aβ25-35 prefers beta sheet structures upon increasing TFE concentrations. On the other hand, the non-toxic scrambled Aβ35-25 peptide only undergoes a transition from random coil to α-helix conformation with increasing TFE. In the interval scan studies, Aβ25-35 did not show any structural transitions, whereas Aβ35-25 showed transition from α-helix to β-sheet conformation. In membrane simulating aqueous SDS micelles, Aβ25-35 showed a transition from random coil to α-helix while Aβ35-25 underwent transition from random coil to β-sheet conformation. Conclusion: Overall, the current results seek new insights into the structural properties of amyloidogenic and the truncated sequence in membrane mimicking solvents.