O-Glycan analysis of cellobiohydrolase I from Neurospora crassa.

We describe here the composition of the O-linked glycans on the Neurospora crassa cellobiohydrolase I (CBHI), which accounts for approximately 40% of the protein secreted by cells growing in the presence of cellulose. CBHI is O-glycosylated with six types of linear, and three types of branched, O-glycans containing approximately equal amounts of mannose and galactose. In addition to the classic fungal O-glycans with reducing end mannoses, we also identified reducing end galactoses which suggest the existence of a protein-O-galactosyltransferase in N. crassa Because of the excellent genetic resources available for N. crassa, the knowledge of the CBHI O-glycans may enable the future evaluation of the role of O-glycosylation on cellulase function and the development of directed O-glycan/cellulase engineering.

Automated Solution-Phase Synthesis of Insect Glycans to Probe the Binding Affinity of Pea Enation Mosaic Virus.

Pea enation mosaic virus (PEMV)--a plant RNA virus transmitted exclusively by aphids--causes disease in multiple food crops. However, the aphid-virus interactions required for disease transmission are poorly understood. For virus transmission, PEMV binds to a heavily glycosylated receptor aminopeptidase N in the pea aphid gut and is transcytosed across the gut epithelium into the aphid body cavity prior to release in saliva as the aphid feeds. To investigate the role of glycans in PEMV-aphid interactions and explore the possibility of viral control through blocking a glycan interaction, we synthesized insect N-glycan terminal trimannosides by automated solution-phase synthesis. The route features a mannose building block with C-5 ester enforcing a ß-linkage, which also provides a site for subsequent chain extension. The resulting insect N-glycan terminal trimannosides with fluorous tags were used in a fluorous microarray to analyze binding with fluorescein isothiocyanate-labeled PEMV; however, no specific binding between the insect glycan and PEMV was detected. To confirm these microarray results, we removed the fluorous tag from the trimannosides for isothermal titration calorimetry studies with unlabeled PEMV. The ITC studies confirmed the microarray results and suggested that this particular glycan-PEMV interaction is not involved in virus uptake and transport through the aphid.

Real-World Evidence of Effectiveness and Safety of Vedolizumab for Inflammatory Bowel Disease in Taiwan: A Prospective Nationwide Registry (VIOLET) Study.

BACKGROUND: This nationwide prospective registry study investigated the real-world effectiveness, safety, and persistence of vedolizumab (VDZ) in inflammatory bowel disease (IBD) patients in Taiwan. Disease relapse rates after VDZ discontinuation due to reimbursement restriction were assessed. METHODS: Data were collected prospectively (January 2018 to May 2020) from the Taiwan Society of IBD registry. RESULTS: Overall, 274 patients (147 ulcerative colitis [UC] patients, 127 Crohn's disease [CD] patients) were included. Among them, 70.7% with UC and 50.4% with CD were biologic-naïve. At 1 year, 76.0%, 58.0%, 35.0%, and 62.2% of UC patients and 57.1%, 71.4%, 33.3%, and 30.0% of CD patients achieved clinical response, clinical remission, steroid-free remission, and mucosal healing, respectively. All patients underwent hepatitis B and tuberculosis screening before initiating biologics, and prophylaxis was recommended when necessary. One hepatitis B carrier, without antiviral prophylaxis due to economic barriers, had hepatitis B reactivation during steroid tapering and increasing azathioprine dosage, which was controlled with an antiviral agent. No tuberculosis reactivation was noted. At 12 months, non-reimbursement-related treatment persistence rates were 94.0% and 82.5% in UC and CD patients, respectively. Moreover, 75.3% of IBD patients discontinued VDZ due to mandatory drug holiday. Relapse rates after VDZ discontinuation at 6 and 12 months were 36.7% and 64.3% in CD patients and 42.9% and 52.4% in UC patients, respectively. CONCLUSIONS: The findings demonstrated VDZ effectiveness in IBD patients in Taiwan, with high treatment persistence rates and favorable safety profiles. A substantial IBD relapse rate was observed in patients who had mandatory drug holiday.

Automated fluorous-assisted solution-phase synthesis of ß-1,2-, 1,3-, and 1,6-mannan oligomers.

Automated solution-phase syntheses of ß-1,2-, 1,3-, and 1,6-mannan oligomers have been accomplished by applying a ß-directing C-5 carboxylate strategy. Fluorous-tag-assisted purification after each reaction cycle allowed the synthesis of short ß-mannan oligomers with limited loading of glycosyl donor-as low as 3.0 equivalents for each glycosylation cycle. This study showed the capability of the automated solution-phase synthesis protocol for synthesizing various challenging glycosides, including use of a C-5 ester as a protecting group that could be converted under reductive conditions to a hydroxymethyl group for chain extension.

Automated Solution-Phase Synthesis of ß-1,4-Mannuronate and ß-1,4-Mannan.

The first automated solution-phase synthesis of ß-1,4-mannuronate and ß-1,4-mannan oligomers has been accomplished by using a ß-directing C-5 carboxylate strategy. By utilizing fluorous-tag assisting purification after repeated reaction cycles, ß-1,4-mannuronate was synthesized up to a hexasaccharide with limited loading of a glycosyl donor (up to 3.5 equiv) for each glycosylation cycle due to the homogeneous solution-phase reaction condition. After a global reduction of the uronates, the ß-1,4-mannan hexasaccharide was obtained, thereby demonstrating a new approach to ß-mannan synthesis.