N-glycan transition of the early developmental stage in Oryza sativa

Recent Developments in Deciphering the Biological Role of Plant Complex N-Glycans

Asparagine (N)-linked protein glycosylation is a ubiquitous co- and posttranslational modification which has a huge impact on the biogenesis and function of proteins and consequently on the development, growth, and physiology of organisms. In mammals, N-glycan processing carried out by Golgi-resident glycosidases and glycosyltransferases creates a number of structurally diverse N-glycans with specific roles in many different biological processes. In plants, complex N-glycan modifications like the attachment of β1,2-xylose, core α1,3-fucose, or the Lewis A-type structures are evolutionary highly conserved, but their biological function is poorly known. Here, I highlight recent developments that contribute to a better understanding of these conserved glycoprotein modifications and discuss future directions to move the field forward.

Structural analysis of N-glycans in medaka gut exposed to silver and titanium dioxide nanoparticles

Nanomaterials are in general use in a broad range of industries. However, there are concerns that their intense use leads to heavy damage to the aquatic environment, and their discharge harms many aquatic organisms. N-Glycans are widely distributed in eukaryotic organisms and are intimately involved in most life phenomena. However, little is known about N-glycans in aquatic organisms exposed to nanomaterials. In this study, we investigated how nanomaterials affect N-glycans in the gut of adult female medaka. We found that silver nanoparticles exposure had little effect on gut N-glycans, whereas titanium dioxide nanoparticles (TiO₂NPs) exposure increased the relative levels of several N-glycans in comparison with control. Structural analysis showed high levels of N-glycans of the high-mannose type, of which five N-glycans were free N-glycans with one β-N-acetylglucosamine residue on the reducing end. The levels of free N-glycans are closely related to protein quality control in the endoplasmic reticulum and cytosol. Our results suggest that TiO₂NPs exposure increases the levels of misfolded glycoproteins, resulting in generation of considerable amounts of free N-glycans. Our findings also suggest that TiO₂NPs exposure suppresses cytosolic α-mannosidase trimming. This study provides new evidence for the effect of TiO₂NPs on medaka gut from the aspect of environmental glycobiology.

ANALYSIS OF CARBOHYDRATES AND GLYCOCONJUGATES BY MATRIX-ASSISTED LASER DESORPTION/IONIZATION MASS SPECTROMETRY: AN UPDATE FOR 2015-2016

This review is the ninth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2016. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented over 30 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show no sign of deminishing. © 2020 Wiley Periodicals, Inc.

Effects of silver nanocolloids on plant complex type N-glycans in Oryza sativa roots

Silver nanomaterials have been mainly developed as antibacterial healthcare products worldwide, because of their antibacterial activity. However, there is little data regarding the potential risks and effects of large amounts of silver nanomaterials on plants. In contrast, N-glycans play important roles in various biological phenomena, and their structures and expressions are sensitive to ambient environmental changes. Therefore, to assesse the effects of silver nanomaterials, we focused on the correlation between N-glycans and the effects of silver nanomaterials in plants and analyzed N-glycan structures in Oryza sativa seedlings exposed to silver nanocolloids (SNCs). The phenotype analysis showed that the shoot was not affected by any SNC concentrations, whereas the high SNC exposed root was seriously damaged. Therefore, we performed comparative N-glycan analysis of roots. As a result, five of total N-glycans were significantly increased in SNC exposed roots, of which one was a free-N-glycan with one beta-N-acetylglucosamine residue at the reducing end. Our results suggest that the transition of plant complex type N-glycans, including free-N-glycans, was caused by abnormalities in O. sativa development, and free-N-glycan itself has an important role in plant development. This study originally adapted glycome transition analysis to environmental toxicology and proposed a new category called “Environmental glycobiology”.