Nissi Varki2 articles listing Nissi Varki in Nature Communications, PNAS, indexed by Paperzzz from Crossref and OSF.Glycosite mapping and in situ mass spectrometry imaging of MUC2 glycopeptides via on-slide mucinase digestion Nature CommunicationsLoss of sialic acid side-chain O -acetylation exacerbates colitis PNAS