O-GlcNAcylation stimulates the deubiquitination activity of USP16 and regulates cell cycle progression.

Histone 2A monoubiquitination (uH2A) underscores a key epigenetic regulation of gene expression. In this report, we show that the deubiquitinase for uH2A, ubiquitin-specific peptidase 16 (USP16), is modified by O-linked N-acetylglucosamine (O-GlcNAc). O-GlcNAcylation involves the installation of the O-GlcNAc moiety to Ser/Thr residues. It crosstalks with Ser/Thr phosphorylation, affects protein-protein interaction, alters enzyme activity or protein folding, and changes protein subcellular localization. In our study, we first confirmed that USP16 is glycosylated on Thr203 and Ser214, as reported in a previous chemoenzymatic screen. We then discovered that mutation of the O-GlcNAcylation site Thr203, which is adjacent to deubiquitination-required Cys204, reduces the deubiquitination activity toward H2AK119ub in vitro and in cells, while mutation on Ser214 had the opposite effects. Using USP16 Ser552 phosphorylation-specific antibodies, we demonstrated that O-GlcNAcylation antagonizes cyclin-dependent kinase 1-mediated phosphorylation and promotes USP16 nuclear export. O-GlcNAcylation of USP16 is also required for deubiquitination of Polo-like kinase 1, a mitotic master kinase, and the subsequent chromosome segregation and cytokinesis. In summary, our study revealed that O-GlcNAcylation of USP16 at Thr203 and Ser214 coordinates deubiquitination of uH2A and Polo-like kinase 1, thus ensuring proper cell cycle progression.

Ageism directed at older nurses in their workplace: A systematic review.

AIMS: To identify and synthesise evidence related to ageism in older regulated nurses' practice settings. DESIGN: A systematic review following Joanna Briggs Institute methodology. METHODS: The review included empirical studies that involved older nurses as the primary study population and studies that focused on ageism in older nurses' work environments, including strategies or interventions to address ageism within the workplace. Following the initial screening, all relevant studies were critically appraised by two reviewers to ensure they were appropriate to include in the review. A synthesis without meta-analysis reporting (SWiM) guideline was employed in the review. DATA SOURCES: Medical Literature Analysis and Retrieval Systems Online, Scopus, Psychological Information Database and Cumulative Index to Nursing and Allied Health Literature and Google Scholar were searched to identify empirical studies and a range of academic institutional websites were accessed for master's and doctoral dissertations and theses. The search covered the period from January 2022 to May 2022, and only publications in English from 2000 onwards were considered. RESULTS: Nineteen studies were included, ten qualitative studies, seven quantitative studies and two mixed methods secondary analyses. Our results revealed that negative perceptions and beliefs about older nurses' competencies and skills prevail in their practice settings, which influences older nurses' health and well-being as well as their continuation of practice. Further, older nurses' continuation of practice can be facilitated by having a positive personal outlook on ageing, meaningful relationships in their practice settings and working in an environment that is age-inclusive. CONCLUSION: To combat ageism in older nurses' practice settings and support their continuation of practice, effective interventions should be organisational-led. The interventions should focus on fostering meaningful relationships between older nurses and their colleagues and managers. Further, healthcare institutions should implement initiatives to promote an age-inclusive work environment that supports an age-diverse nursing workforce. IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE: The review findings offer insights for healthcare managers, policymakers and researchers, emphasising the need for anti-ageism policies in healthcare organisations. According to WHO (2021), educational activities such as role-playing and simulation during in-service training may also be effective interventions. Additionally, incorporating anti-ageism initiatives into staff meetings and mandating anti-ageism training could support the continuation of practice for older nurses while fostering a more age-diverse nursing workforce. IMPACT: We found evidence on the presence of ageism in older nurses' workplace and the detrimental effects of ageism on older nurses' well-being and continuation of practice. Importantly, we identified a lack of organisational initiatives to address ageism and support older nurses. These findings should encourage healthcare organisations to address ageism in older nurses' practice settings and prompt policymakers to develop age-inclusive policies that support older nurses' continuation of practice. REPORTING METHOD: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Synthesis Without Meta-analysis checklists were used to report the screening process. TRIAL AND PROTOCOL REGISTRATION: The PROSPERO registration number for the review was CRD42022320214 (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022320214). No Patient or Public Contribution.

Purification and Biochemical Characterization of Polyphenol Oxidase Extracted from Wheat Bran (Wan grano).

Currently, little is known about the characteristics of polyphenol oxidase from wheat bran, which is closely linked to the browning of wheat product. The wheat PPO was purified by ammonium sulfate precipitation, DEAE-Sepharose ion-exchange column, and Superdex G-75 chromatography column. Purified wheat PPO activity was 11.05-fold higher, its specific activity was 1365.12 U/mg, and its yield was 8.46%. SDS-PAGE showed that the molecular weight of wheat PPO was approximately 21 kDa. Its optimal pH and temperature were 6.5 and 35 °C for catechol as substrate, respectively. Twelve phenolic substrates from wheat and green tea were used for analyzing the substrate specificity. Wheat PPO showed the highest affinity to catechol due to its maximum Vmax (517.55 U·mL-1·min-1) and low Km (6.36 mM) values. Docking analysis revealed strong affinities between catechol, gallic acid, EGCG, and EC with binding energies of -5.28 kcal/mol, -4.65 kcal/mol, -4.21 kcal/mol, and -5.62 kcal/mol, respectively, for PPO. Sodium sulfite, ascorbic acid, and sodium bisulfite dramatically inhibited wheat PPO activity. Cu2+ and Ca2+ at 10 mM were considered potent activators and inhibitors for wheat PPO, respectively. This report provides a theoretical basis for controlling the enzymatic browning of wheat products fortified with green tea.

Microencapsulation as a Protective Strategy for Sialylated Immunoglobulin G: Efficacy in Alleviating Symptoms of Dextran Sulfate Sodium-Induced Colitis in Mice and Potential Mechanisms.

Sialylated immunoglobulin G (IgG) is a vital glycoprotein in breast milk with the ability to promote the growth of Bifidobacterium in gut microbiota and relieve inflammatory bowel disease (IBD) symptoms in vitro. Here, it was found that the microcapsules with sialylated IgG could protect and release sialylated IgG with its structure and function in the intestine. Furthermore, the sialylated IgG microcapsules alleviated the clinical symptoms (body weight, feed quantity, and colon length loss), decreased disease activity index score, suppressed the production of pro-inflammatory cytokines (TNF-α, IL-6, IL-1ß, IFN-γ, and MCP-1) and endotoxin (lipopolysaccharide), and enhanced the intestinal mucosal barrier (Claudin1, Muc2, Occludin, and ZO-1) in dextran sulfate sodium (DSS)-induced colitis mice. Additionally, the sialylated IgG microcapsules improved the gut microbiota by increasing the relative abundance of critical microbe Bifidobacterium bifidum and promoted the production of short-chain fatty acids (SCFAs). Correlation analysis indicated that the key microbes were strongly correlated with pro-inflammatory factors, clinical symptoms, tight junction protein, and SCFAs. These findings suggest that the sialylated IgG microcapsules have the potential to be used as a novel therapeutic approach for treating IBD.

Role of histone variants H2BC1 and H2AZ.2 in H2AK119ub nucleosome organization and Polycomb gene silencing.

Ubiquitination of histone H2A at lysine 119 residue (H2AK119ub) plays critical roles in a wide range of physiological processes, including Polycomb gene silencing 1,2 , replication 3-5 , DNA damage repair 6-10 , X inactivation 11,12 , and heterochromatin organization 13,14 . However, the underlying mechanism and structural basis of H2AK119ub remains largely elusive. In this study, we report that H2AK119ub nucleosomes have a unique composition, containing histone variants H2BC1 and H2AZ.2, and importantly, this composition is required for H2AK119ub and Polycomb gene silencing. Using the UAB domain of RSF1, we purified H2AK119ub nucleosomes to a sufficient amount and purity. Mass spectrometry analyses revealed that H2AK119ub nucleosomes contain the histone variants H2BC1 and H2AZ.2. A cryo-EM study resolved the structure of native H2AK119ub nucleosomes to a 2.6A resolution, confirming H2BC1 in one subgroup of H2AK119ub nucleosomes. Tandem GST-UAB pulldown, Flag-H2AZ.2, and HA-H2BC1 immunoprecipitation revealed that H2AK119ub nucleosomes could be separated into distinct subgroups, suggesting their composition heterogeneity and potential dynamic organization. Knockout or knockdown of H2BC1 or H2AZ.2 reduced cellular H2AK119ub levels, establishing H2BC1 and H2AZ.2 as critical determinants of H2AK119ub. Furthermore, genomic binding profiles of H2BC1 and H2AZ.2 overlapped significantly with H2AK119ub binding, with the most significant overlapping in the gene body and intergenic regions. Finally, assays in developing embryos reveal an interaction of H2AZ.2, H2BC1, and RING1A in vivo . Thus, this study revealed, for the first time, that the H2AK119ub nucleosome has a unique composition, and this composition is required for H2AK119ub and Polycomb gene silencing.

The male pachynema-specific protein MAPS drives phase separation in vitro and regulates sex body formation and chromatin behaviors in vivo.

Dynamic chromosome remodeling and nuclear compartmentalization take place during mammalian meiotic prophase I. We report here that the crucial roles of male pachynema-specific protein (MAPS) in pachynema progression might be mediated by its liquid-liquid phase separation in vitro and in cellulo. MAPS forms distinguishable liquid phases, and deletion or mutations of its N-terminal amino acids (aa) 2-9 disrupt its secondary structure and charge properties, impeding phase separation. Maps-/- pachytene spermatocytes exhibit defects in nucleus compartmentalization, including defects in forming sex bodies, altered nucleosome composition, and disordered chromatin accessibility. MapsΔ2-9/Δ2-9 male mice expressing MAPS protein lacking aa 2-9 phenocopy Maps-/- mice. Moreover, a frameshift mutation in C3orf62, the human counterpart of Maps, is correlated with nonobstructive azoospermia in a patient exhibiting pachynema arrest in spermatocyte development. Hence, the phase separation property of MAPS seems essential for pachynema progression in mouse and human spermatocytes.