Dudek, A. | Search bioRxiv

bioRxiv2026

Crude Fucus vesiculosus fucoidan demonstrates superior SARS-CoV-2 antiviral activity compared to its pure form: binding kinetics and functional studies

Fucoidans have been widely reported to show SARS-CoV-2 antiviral activity. In this study, we observed a striking difference in the inhibitory potency between two commercially available fucoidans: Fucus vesiculosus crude (Fvc) and pure (Fvp). SEC-MALS analysis revealed two molecular weight populations for Fvc (1098 kDa, 58.58 kDa) and one for Fvp (40.48 kDa). At micromolar concentrations of fucoidans, the binding affinities (KDs) of Fvc_1098 (223 nM) and Fvc_58 (4.27 {micro}M) for the amine-biotinylated SARS-CoV-2 receptor binding domain (RBD) were higher than that of Fvp (76.5 {micro}M). At nanomolar concentrations, binding was observed only to the Avi-tag-, but not amine-biotinylated RBDs, suggesting better accessibility of their binding sites. The association rates (kon) were faster for Fvc than for Fvp. Similarly, affinities of Fvc_1098 (23.4 nM) and Fvc_58 (4.48 M) for ACE2 were greater than that of Fvp (66.8 M), indicating that Fvc can bind directly to both RBD and ACE2. Fvc demonstrated enhanced inhibitory potency (IC50 = 58 g/mL) compared to Fvp (IC50 > 239 g/mL) in the pseudovirus entry assay and did not induce cytotoxicity in HEK293T cells. In conclusion, crude fucoidan with high fucose content and high molecular weight shows promising antiviral activity.

biochemistry↗

bioRxiv2020

Morphology and immunhistchemical characteristics of the otic ganglion in chinchilla (Chinchila laniger Molina).

The available literature provides relatively little information on the morphology of the autonomic head ganglia in rodents including their neurochemical codding. The present study was thus designed to investigate the morphology and neurochemical properties of the otic ganglion in the chinchilla. The results will contribute to our knowledge of the organization of the autonomic nerve system in mammals. Morphological investigations of the otic ganglion were performed using the modified acetylcholinesterase method. The cellular structure was investigated with histological techniques and neurochemical properties were studied with double-labelling immunofluorescence method Macromorphological investigations allowed the otic ganglion to be identified as a compact, oval agglomeration of neurons and nerve fibers located inside the skull on the medial surface of the mandibular nerve, just above the oval foramen. Multidimensional cross-sections revealed densely arranged neuronal perikarya and two populations of nerve cells differing in size were distinguished. The large cells (40-50 m) accounted for about 80% of the neurons in the otic ganglion cross-sections. Moreover, a small number of intraganglionic nerve fibers was observed. Immunohistochemical staining revealed that over 85% of the neuronal cell bodies in the otic ganglion contained immunoreactivity to VAChT or ChAT. VIP-immunoreactive perikarya comprised approximately 10% of the ganglionic cells. Double staining revealed the presence of VAChT and NOS-positive neurons which amounted to about 45% of the nerve cells in the otic ganglion. NOS-positive only perikarya comprised approx. 15% of all the neurons. Immunoreactivity to enkephalin, substance P, somatostatin and galanin was expressed in single nerve cell bodies and nerve fibres except numerous SP-positive intraganglionic nerve fibres. Some of them stained also for CGRP. Single neurons stained for TH. The present results, compared with previous findings, suggest the existence interspecies differences in the morphology, cellular structure and immunohistochemical properties of the head autonomic ganglia in mammals.

neuroscience↗