Conformational and Electronic Variations in 1,2- and 1,5a-Cyclophellitols and their Impact on Retaining α-Glucosidase Inhibition.

Glycoside hydrolases (glycosidases) take part in myriad biological processes and are important therapeutic targets. Competitive and mechanism-based inhibitors are useful tools to dissect their biological role and comprise a good starting point for drug discovery. The natural product, cyclophellitol, a mechanism-based, covalent and irreversible retaining ß-glucosidase inhibitor has inspired the design of diverse α- and ß-glycosidase inhibitor and activity-based probe scaffolds. Here, we sought to deepen our understanding of the structural and functional requirements of cyclophellitol-type compounds for effective human α-glucosidase inhibition. We synthesized a comprehensive set of α-configured 1,2- and 1,5a-cyclophellitol analogues bearing a variety of electrophilic traps. The inhibitory potency of these compounds was assessed towards both lysosomal and ER retaining α-glucosidases. These studies revealed the 1,5a-cyclophellitols to be the most potent retaining α-glucosidase inhibitors, with the nature of the electrophile determining inhibitory mode of action (covalent or non-covalent). DFT calculations support the ability of the 1,5a-cyclophellitols, but not the 1,2-congeners, to adopt conformations that mimic either the Michaelis complex or transition state of α-glucosidases.

Comparison of prefrontal cortex sucrose seeking ensembles engaged in multiple seeking sessions: Context is key.

Encoding of memories, including those associated with prior drug or reward, is thought to take place within distinct populations of neurons, termed ensembles. Neuronal ensembles for drug- and reward-seeking have been identified in regions of the medial prefrontal cortex, but much of our understanding of these ensembles is based on experiments that take place in a single reward-associated environment and measure ensemble encoding over short durations of time. In contrast, reward seeking behavior is evident across different reward-associated environments and persists over time. Using TetTag mice and Fos immunohistochemistry, we examined the relationship between persistent sucrose-seeking and ensemble encoding in mice that undergo seeking sessions in the same or different sucrose self-administration contexts 2 weeks apart. We found that prelimbic (PrL) and anterior cingulate cortex ensembles tagged in the first seeking session were highly sensitive to the context in which a second seeking session took place: reactivation of these ensembles was reduced in the same context but elevated in a distinct sucrose self-administration context. Correlational analyses revealed that ensemble reactivation in the PrL was proportional to the persistence of sucrose seeking behavior across sessions in differing ways in female mice. In the same context, reactivation was proportional to the persistence of non-reinforced operant responses, whereas in a distinct context, reactivation was proportional to the persistence of non-reinforced head entries into the sucrose receptacle. This study underlines the importance of the medial prefrontal cortex importance in maintaining a reward-seeking ensemble over time and identifies context-dependent changes in behavioral correlates of ensemble reactivation.

Structure and Mutation of the Native Amine Dehydrogenase MATOUAmDH2.

Native amine dehydrogenases (nat-AmDHs) have recently emerged as a potentially valuable new reservoir of enzymes for the sustainable and selective synthesis of chiral amines, catalyzing the NAD(P)H-dependent ammoniation of carbonyl compounds with high activity and selectivity. MATOUAmDH2, recently identified from the Marine Atlas of Tara Oceans Unigenes (MATOUv1) database of eukaryotic genes, displays exceptional catalytic performance against its best identified substrate, isobutyraldehyde, as well as having broader substrate scope than other nat-AmDHs. In the interests of providing a platform for the rational engineering of this and other nat-AmDHs, we have determined the structure of MATOUAmDH2 in complex with NADP+ and also with the cofactor and cyclohexylamine. Monomers within the structure are representative of more open and closed conformations of the enzyme and illustrate the profound changes undergone by nat-AmDHs during the catalytic cycle. An alanine screen of active site residues revealed that M215A and L180A are more active than the wild-type enzyme for the amination of cyclohexanone with ammonia and methylamine respectively; the latter suggests that AmDHs have the potential to be engineered for the improved production of secondary amines.

Structure-guided design of C3-branched swainsonine as potent and selective human Golgi α-mannosidase (GMII) inhibitor.

The human Golgi α-mannosidase, hGMII, removes two mannose residues from GlcNAc-Man5GlcNAc2 to produce GlcNAcMan3GlcNAc2, the precursor of all complex N-glycans including tumour-associated ones. The natural product GMII inhibitor, swainsonine, blocks processing of cancer-associated N-glycans, but also inhibits the four other human α-mannosidases, rendering it unsuitable for clinical use. Our previous structure-guided screening of iminosugar pyrrolidine and piperidine fragments identified two micromolar hGMII inhibitors occupying the enzyme active pockets in adjacent, partially overlapping sites. Here we demonstrate that fusing these fragments yields swainsonine-configured indolizidines featuring a C3-substituent that act as selective hGMII inhibitors. Our structure-guided GMII-selective inhibitor design complements a recent combinatorial approach that yielded similarly configured and substituted indolizidine GMII inhibitors, and holds promise for the potential future development of anti-cancer agents targeting Golgi N-glycan processing.

Changing bodies: A scoping review and thematic analysis of family experience during serious childhood illness.

This scoping review has investigated experiences of children and parents encountering in-patient treatment for serious childhood illness, including current or potential use of technology as a support mechanism. The research questions were 1. What do children experience during illness and treatment? 2. What do parents experience when their child is seriously ill in hospital? 3. What tech and non-tech interventions support children's experience of in-patient care? The research team identified n = 22 relevant studies for review through JSTOR, Web of Science, SCOPUS and Science Direct. A thematic analysis of reviewed studies identified three key themes reflecting our research questions: Children in hospital, Parents and their children, and Information and technology. Our findings reflect that information giving, kindness and play are central in hospital experiences. Parent and child needs in hospital are interwoven and under researched. Children reveal themselves as active producers of pseudo-safe spaces who continue to prioritise normal child and adolescent experiences during in-patient care.

Thermostable homologues of the periplasmic siderophore-binding protein CeuE from Geobacillus stearothermophilus and Parageobacillus thermoglucosidasius.

Siderophore-binding proteins from two thermophilic bacteria, Geobacillus stearothermophilus and Parageobacillus thermoglucosidasius, were identified from a search of sequence databases, cloned and overexpressed. They are homologues of the well characterized protein CjCeuE from Campylobacter jejuni. The iron-binding histidine and tyrosine residues are conserved in both thermophiles. Crystal structures were determined of the apo proteins and of their complexes with iron(III)-azotochelin and its analogue iron(III)-5-LICAM. The thermostability of both homologues was shown to be about 20°C higher than that of CjCeuE. Similarly, the tolerance of the homologues to the organic solvent dimethylformamide (DMF) was enhanced, as reflected by the respective binding constants for these ligands measured in aqueous buffer at pH 7.5 in the absence and presence of 10% and 20% DMF. Consequently, these thermophilic homologues offer advantages in the development of artificial metalloenzymes using the CeuE family.

The Genetic Links to Anxiety and Depression (GLAD) Study: Online recruitment into the largest recontactable study of depression and anxiety.

BACKGROUND: Anxiety and depression are common, debilitating and costly. These disorders are influenced by multiple risk factors, from genes to psychological vulnerabilities and environmental stressors, but research is hampered by a lack of sufficiently large comprehensive studies. We are recruiting 40,000 individuals with lifetime depression or anxiety and broad assessment of risks to facilitate future research. METHODS: The Genetic Links to Anxiety and Depression (GLAD) Study (www.gladstudy.org.uk) recruits individuals with depression or anxiety into the NIHR Mental Health BioResource. Participants invited to join the study (via media campaigns) provide demographic, environmental and genetic data, and consent for medical record linkage and recontact. RESULTS: Online recruitment was effective; 42,531 participants consented and 27,776 completed the questionnaire by end of July 2019. Participants' questionnaire data identified very high rates of recurrent depression, severe anxiety, and comorbidity. Participants reported high rates of treatment receipt. The age profile of the sample is biased toward young adults, with higher recruitment of females and the more educated, especially at younger ages. DISCUSSION: This paper describes the study methodology and descriptive data for GLAD, which represents a large, recontactable resource that will enable future research into risks, outcomes, and treatment for anxiety and depression.

A new thorium-229 reference material.

A new reference material was characterized for 229Th molality and thorium isotope amount ratios. This reference material is intended for use in nuclear forensic analyses as an isotope dilution mass spectrometry spike. The reference material value and expanded uncertainty (k = 2) for the 229Th molality is (1.1498 ± 0.0016) × 10-10molg-1 solution. The value and expanded uncertainty (k = 2) for the n(230Th)/n(229Th) ratio is (5.18 ± 0.26) × 10-5 and the n(232Th)/n(229Th) ratio is (3.815 ± 0.092) × 10-4.

New determination of the 229Th half-life.

A new determination of the 229Th half-life was made based on measurements of the 229Th massic activity of a high-purity solution for which the 229Th molality had previously been measured. The 229Th massic activity was measured by direct comparison with SRM 4328C using 4παß liquid scintillation counting, NaI counting, and standard addition liquid scintillation counting. The massic activity was confirmed by isotope dilution alpha spectrometry measurements. The calculated 229Th half-life is (7825 ± 87) years (k = 2), which is shorter than the three most recent half-life determinations but is consistent with these values within uncertainties.

Electrodeposition of Copper for Three-Dimensional Metamaterial Fabrication.

Metamaterials typically consist of metallic and dielectric repeating structures. Electrodeposition of copper is the preferred approach to fabricating the metallic part of the metamaterials of interest in this study. The highly variant topography requires chemical additives, like chloride ions, 3-mercapto-1-propanesulfonic acid (MPSA), polyethylene glycol (PEG), and polyvinylpyrrolidone (PVP) to enhance bottom-up superfilling while maintaining terrace flatness. This study focuses on both experimental and computational investigations of the degradation potential of the additives and their adsorption mechanism in a highly acidic copper electrolyte in order to optimally parametrize the copper electrodeposition process. Results show Cl-MPSA-PEG-PVP additives perform well, but substitution of PVP with Janus Green B provides better terrace leveling. Additionally, NMR data show a quick and complete conversion of MPSA to bis(3-sulfopropyl) disulfide (SPS) in the acidic copper bath. Finally, FEM simulations further show that the accelerator species may initially accumulate and be transported vertically until overplating, whereby they are transported laterally.

Water partitioning in "dry" poly(ethylene oxide) alcohol (CmEn) nonionic surfactant--a proton NMR study.

A proton NMR titration study is presented where in small increments quantities of water were added to "dry" CmEn nonionic surfactant. For a particular range of compositions, two resonances for the water/hydroxyl protons were observed that display large chemical shift increases as water content is increased indicating that water must partition between two chemical environments with a surprisingly slow chemical exchange rate. A detailed mechanism of how the increasing amounts of water are incorporated into the surfactant medium is presented accounting for all observed spectral changes.