The primary familial brain calcification associated protein MYORG is an α-galactosidase with restricted substrate specificity

Primary familial brain calcification (PFBC) is characterised by abnormal deposits of calcium phosphate within various regions of the brain that are associated with severe cognitive impairments, psychiatric conditions, and movement disorders. Recent studies in diverse populations have shown a link between mutations in myogenesis-regulating glycosidase (MYORG) and the development of this disease. MYORG is a member of glycoside hydrolase (GH) family 31 (GH31) and, like the other mammalian GH31 enzyme α-glucosidase II, this enzyme is found in the lumen of the endoplasmic reticulum (ER). Though presumed to act as an α-glucosidase due to its localization and sequence relatedness to α-glucosidase II, MYORG has never been shown to exhibit catalytic activity. Here, we show that MYORG is an α-galactosidase and present the high-resolution crystal structure of MYORG in complex with substrate and inhibitor. Using these structures, we map detrimental mutations that are associated with MYORG-associated brain calcification and define how these mutations may drive disease progression through loss of enzymatic activity. Finally, we also detail the thermal stabilisation of MYORG afforded by a clinically approved small molecule ligand, opening the possibility of using pharmacological chaperones to enhance the activity of mutant forms of MYORG

A pragmatic effectiveness study of 10-session cognitive behavioural therapy (CBT-T) for eating disorders: Targeting barriers to treatment provision

Objective Ten‐session cognitive behavioural therapy (CBT‐T) for transdiagnostic eating disorders targets several barriers to treatment, including cost, therapist expertise, and lengthy wait lists. Method We used a case series design to investigate the effectiveness of CBT‐T delivered by trainee psychologists in a postgraduate training clinic. Participants were randomly allocated to commence treatment either immediately or after a 4‐week waitlist period. CBT‐T was delivered to 52 patients, by six different trainees under supervision. Measures of eating disorder cognitions and behaviours, quality of life, and general psychopathology were examined in completer and intention‐to‐treat analyses using multilevel modelling. Last observation carried forward was applied for abstinence, remission, and good outcome analyses to aid comparison with prior studies. Results Significant improvements, associated with medium to large effect sizes, were found for eating disorder cognitions, behaviours quality of life, and negative affect from baseline to posttreatment, and at 1‐ and 3‐month follow‐up. Attrition (38.5%) was comparable with other treatment studies. Conclusion Results provide evidence for the effectiveness of CBT‐T delivered by trainee psychologists for transdiagnostic eating disorder patients, thus tackling some important barriers for treatment. Longer follow‐up, randomised controlled trial designs, and moderator analyses will provide more robust evidence about which patients do best with a shorter therapy

Large-Scale Reassessment of In-Vineyard Smoke-Taint Grapevine Protection Strategies and the Development of Predictive Off-Vine Models

Smoke taint in wine is thought to be caused by smoke-derived volatile phenols (VPs) that are absorbed into grape tissues, trapped as conjugates that are imperceptible by smell, and subsequently released into wines as their free odor-active forms via metabolism by yeasts during fermentation. Blocking VP uptake into grapes would, therefore, be an effective way for vineyards to protect ripening grape crops exposed to smoke. Here, we re-evaluated a biofilm that had previously shown promise in pilot studies in reducing levels of smoke-derived VPs. A suite of nine free and acid-labile VPs were quantitated in Pinot Noir grapes that had been exposed to smoke after being coated with the biofilm one, seven or 14 days earlier. In contrast with earlier studies, our results demonstrated that in all cases, the biofilm treatments led to increased concentrations of both free and total VPs in smoke-exposed grapes, with earlier applications elevating concentrations of some VPs more than the later time points. Tracking VP concentrations through the grape ripening process demonstrated that some (phenol, p/m-cresol, and guaiacol) were not entirely sequestered in grapes as acid-labile conjugates, suggesting the presence of VP storage forms beyond simple glycosides. Free VPs in grapes, though a minor portion of the total, most clearly correlated with concentrations present in the resulting wines. Finally, red table grapes, available year round, were observed to replicate the effects of the biofilm treatments and were capable of transforming most VPs into acid-labile conjugates in under 24 h, indicating that they might be an effective model for rapidly assessing smoke-taint prophylactic products in the laboratory.Science, Irving K. Barber Faculty of (Okanagan)Biology, Department of (Okanagan)Chemistry, Department of (Okanagan)ReviewedFacult

The Global Assessment of Oilseed Brassica Crop Species Yield, Yield Stability and the Underlying Genetics

The global demand for oilseeds is increasing along with the human population. The family of Brassicaceae crops are no exception, typically harvested as a valuable source of oil, rich in beneficial molecules important for human health. The global capacity for improving Brassica yield has steadily risen over the last 50 years, with the major crop Brassica napus (rapeseed, canola) production increasing to ~72 Gt in 2020. In contrast, the production of Brassica mustard crops has fluctuated, rarely improving in farming efficiency. The drastic increase in global yield of B. napus is largely due to the demand for a stable source of cooking oil. Furthermore, with the adoption of highly efficient farming techniques, yield enhancement programs, breeding programs, the integration of high-throughput phenotyping technology and establishing the underlying genetics, B. napus yields have increased by >450 fold since 1978. Yield stability has been improved with new management strategies targeting diseases and pests, as well as by understanding the complex interaction of environment, phenotype and genotype. This review assesses the global yield and yield stability of agriculturally important oilseed Brassica species and discusses how contemporary farming and genetic techniques have driven improvements

ER lumen α-glycosidases play roles in <i>N</i>-glycan processing.

Crystal structures of Mus musculus α-glucosidase I (PDB: 5MHF) and II (PDB: 5F0E). The transfer of Glc3Man9GlcNAc2 onto nascent polypeptide chains initiates an ER localised quality control process wherein the terminal nonreducing α1-2-linked glucose and the 2 inner α1-3-linked glucose residues are hydrolysed by α-Glu I and α-Glu II, respectively. Retention in the ER of glycoproteins bearing the innermost α1-3-linked glucose by the chaperones calnexin and calreticulin coupled with re-attachment of α1-3-linked glucose to misfolded proteins by UDP-glucose:glycoprotein glucosyltransferase regulates protein quality control. The function of MYORG within the ER and relevance to glycoprotein processing is unknown. The symbols used for monosaccharides follow the recommendations of the CFG. CFG, Consortium for Functional Glycomics; ER, endoplasmic reticulum; MYORG, myogenesis-regulating glycosidase.</p

MYORG is a dimeric α-galactosidase that shows distinct substrate specificity.

(a) SEC-MALLS traces of glycosylated and EndoH-treated MYORG. (b) Fluorescent activity assay of MYORG against 4MU-α-linked substrates. Data is mean from 3 technical replicates ± standard deviations. (c) Example isothermal titration calorimetry trace of DGJ binding to MYORG. (ci) Raw baseline subtracted injection profile of the ITC experiment. (cii) Titration curve with points in blue and fitted line in black. (d) Activity screening of MYORG against disaccharides. Experiment repeated twice with 3 technical repeats in each replicate. (e) Michaelis–Menten kinetics for processing of Gal-α1-4-Glc by MYORG. Data from 3 technical repeats. All raw data underlying graphs can be found in S1 Data. BGBT, blood group B trisaccharide; DGJ, deoxygalactonojirimycin; MYORG, myogenesis-regulating glycosidase.</p

The region of MYORG used for docking simulations.

Chain B of MYORG from the MYORG-Gal-α1,4-Glc complex was used for docking. Docking region enclosed in green square. Acid/base and nucleophile residue coloured in magenta. (PDF)</p

MYORG is a membrane bound dimer that selectively binds an unusual Gal-α1,4-Glc epitope.

(a) Domain boundaries of MYORG with numbering representing the last residue of the domain. (b) Cartoon ribbon representation of MYORG with N-glycans depicted as sticks with the glycosylated Asn residues labelled. (c) The MYORG dimer arrangement showing the insert region and the expected orientation of MYORG with respect to the ER membrane based on analyses using PSIPRED [27], DISOPRED [28], and MEMSAT [29]. (d) Comparison of the active site of MYORG (blue, residue labelling in black) with that of Mmα-Glu-II (purple; PDB: 5H9O). D-glucose is bound by Mmα-Glu-II and is depicted in pink. (e) Residues involved in the positioning and binding of DGJ. (f) Residues involved in binding Gal-α1,4-Glc. Dashed lines in (e) and (f) represent hydrogen bonding. Magenta sticks are used to emphasise the catalytic acid (D520, mutated to N520 in (f)) and nucleophile (D463) residues. DGJ, deoxygalactonojirimycin; ER, endoplasmic reticulum; MYORG, myogenesis-regulating glycosidase; NTβSD, N-terminal β-sheet domain; PβSD, proximal β-sheet domain; TMD, transmembrane domain.</p

Host responses to Clostridium perfringens challenge in a chicken model of chronic stress

Background: This study utilized a chicken model of chronic physiological stress mediated by corticosterone (CORT) administration to ascertain how various host metrics are altered upon challenge with Clostridium perfringens. Necrotic enteritis (NE) is a disease of the small intestine of chickens incited by C. perfringens, which can result in elevated morbidity and mortality. The objective of the current study was to investigate how physiological stress alters host responses and predisposes birds to subclinical NE. Results: Birds administered CORT exhibited higher densities of C. perfringens in their intestine, and this corresponded to altered production of intestinal mucus. Characterization of mucus showed that C. perfringens treatment altered the relative abundance of five glycans. Birds inoculated with C. perfringens did not exhibit evidence of acute morbidity. However, histopathologic changes were observed in the small intestine of infected birds. Birds administered CORT showed altered gene expression of tight junction proteins (i.e. CLDN3 and CLDN5) and toll-like receptors (i.e. TLR2 and TLR15) in the small intestine. Moreover, birds administered CORT exhibited increased expression of IL2 and G-CSF in the spleen, and IL1β, IL2, IL18, IFNγ, and IL6 in the thymus. Body weight gain was impaired only in birds that were administered CORT and challenged with C. perfringens. Conclusion: CORT administration modulated a number of host functions, which corresponded to increased densities of C. perfringens in the small intestine and weight gain impairment in chickens. Importantly, results implicate physiological stress as an important predisposing factor to NE, which emphasizes the importance of managing stress to optimize chicken health.Arts and Sciences, Irving K. Barber School of (Okanagan)Non UBCBiology, Department of (Okanagan)Chemistry, Department of (Okanagan)ReviewedFacult