Sialic acids as link to Japanese scientists

Abstract

This manuscript is dedicated to Prof. Tamio Yamakawa and describes my cooperations on sialic acid-related topics with Japanese scientists during the last 40 years. We studied sialic acids and their O-acetylated derivatives in the sea urchin Pseudocentrotus depressus, in Halocynthia species, and in human and bovine milk. In seafood we mainly searched for N-glycolylneuraminic acid. With synthetic substrates it was shown that sialic acid O-acetylation at C-4 hinders the activity of sialidases, with the exception of viral enzymes. The biosynthesis of Neu5Gc was discussed and the distribution of this sialic acid in dogs followed in modern literature and reviewed regarding their migration. An excellent source of sialic acids is edible bird nest substance (Collocalia mucin) which was used for the synthesis of sialylation inhibitors.

Effects of Gangliosides on Spermatozoa, Oocytes, and Preimplantation Embryos

“…Gangliosides are sialic acid-containing glycosphingolipids and are cell type-specific. Sialic acids are a large group of nine carbon α-keto acids that play a diversity of biological functions in cells [48,49]. Depending on the number of sialic acid residues on the inner galactose, gangliosides belong either to the a-ganglio series, the b-ganglio series, or the c-series [50].…”

N-Glycolylneuraminic Acid as a Receptor for Influenza A Viruses

“…However, several other mammalian species have also independently lost the function of the cytidine monophosphate (CMP)-N-acetyl neuraminic acid hydroxylase (CMAH) and are, therefore, unable to synthesize N-glycolyl and only express N-acetyl. These species include dogs, ferrets, and seals (Ng et al, 2014; Peri et al, 2018; Schauer, 2016). Other mammalian species, such as horses and pigs, do express a functional CMAH enzyme and can predominantly express N-glycolyl instead of N-acetyl (Ito et al, 2000).…”

Elicited and pre‐existing anti‐Neu5Gc antibodies differentially affect human endothelial cells transcriptome

“…Humans cannot synthetize Neu5Gc or α1,3Gal endogenously, and as a result healthy sera contains high levels of antibodies directed against glycans containing a terminal Neu5Gc [1][2][3] or α1,3Gal 4 that are absent in humans but are present on glycoproteins and glycolipids of most non-human mammals. Besides being a potential obstacle to xenotransplantation 5 or to safe clinical utilization of animal-derived biodevices such as biological heart valves 6 or molecules, [7][8][9] the presence of circulating anti-Neu5Gc antibodies (Abs) in all normal individuals creates a unique biological situation since the diet-derived Neu5Gc antigen can be absorbed and deposited in low amounts on endothelia and on some epithelia 10,11 of healthy humans.…”