A brain-derived MeCP2 complex supports a role for MeCP2 in RNA processing

Mutations in MECP2 (methyl-CpG-binding protein 2) are linked to the severe postnatal neurodevelopmental disorder RTT (Rett syndrome). MeCP2 was originally characterized as a transcriptional repressor that preferentially bound methylated DNA; however, recent results indicate MeCP2 is a multifunctional protein. MeCP2 binding is now associated with certain expressed genes and involved in nuclear organization as well, indicating that its gene regulatory function is context-dependent. In addition, MeCP2 is proposed to regulate mRNA splicing and a mouse model for RTT shows aberrant mRNA splicing. To further understand MeCP2 and potential roles in RTT pathogenesis, we have employed a biochemical approach to identify the MeCP2 protein complexes present in the mammalian brain. We show that MeCP2 exists in at least four biochemically distinct pools in the brain and characterize one novel brain-derived MeCP2 complex that contains the splicing factor Prpf3 (pre-mRNA processing factor 3). MeCP2 directly interacts with Prpf3 in vitro and in vivo and many MECP2 RTT truncations disrupt the MeCP2-Prpf3 complex. In addition, MeCP2 and Prpf3 associate in vivo with mRNAs from genes known to be expressed when their promoters are associated with MeCP2. These results support a role for MeCP2 in mRNA biogenesis and suggest an additional mechanism for RTT pathophysiology

Optimization of liquid chromatography ...

Liquid chromatography with electrochemical detection has become an established technique for the determination of catecholamines, indoleamines, and related enzymes. Previous work in this area has utilized lower efficiency columns, containing packing materials with diameters of five and ten microns. The recent introduction of higher efficiency three micron columns offers the possibility of a significant decrease in the required analysis time. In an attempt to increase sample throughput in our laboratory, these columns were evaluted for utilization with electrochemical detection.The separation of various neurochemicals was also optimized by adjusting the mobile phase composition. This resulted in the separation of eighteen compounds on one column in less than four minutes, while the same separation can be obtained with a higher degree of resolution on a second column in approximately seven minutes. The general applicability of this technique was demonstrated by its employment in the determination of catecholamines, indoleamines, and related metabolites in whole mouse brains.Due to the high efficiency of these columns, the eluting peaks are extremely narrow. Instrumental components and various other parameters can drastically broaden the narrow peaks and negate the advantage of these columns. Both the liquid chromatograph and the electrochemical detector were optimized in order to minimize the effects of instrumental band broadening. The optimization process included an examination of system dead volume, pump pulsation, potentiostat time constant, electrochemical cell dead volume, detector spacer thickness, electrode diameter, and electrode material. The results of these investigations showed that an optimized electrochemical detector may be used with these columns without deleteriously affecting their performance. The optimum system includes a modified detector cell with a 1/32 inch diameter carbon paste working electrode, a 0.002 inch spacer thickness, and a time constant of 0.05 seconds

Challenges in the delivery of sex education for people with intellectual disabilities: A Chinese cultural-contextual analysis

Background: Staff members' views can have a significant impact on sexuality issues of people with intellectual disabilities. Research on the impact of sociocultural factors in this area in the Chinese context is sparse. Methods: Semi-structured interviews were conducted with seven professionals (social worker, nurse, life skills trainer and manager) to explore their experiences of and attitudes towards the sexual needs of people with intellectual disabilities by applying interpretative phenomenological analysis. Results: The study identified two major themes, each with two sub-themes: 1. Professional handling of the sexual needs of people with intellectual disabilities (sex education and intervention); 2. Barriers (incompatible approaches and parental resistance). Participants also experienced feelings of resignation facing the barriers they encountered. Collectivism and cultural view about sex are potentially the influencing factors. Conclusion: This study highlights the need to adopt an evidence-based sex education programme whose content and delivery should take account of cultural factors

Arp2/3 nucleates F-actin coating of fusing insulin granules in pancreatic β cells to control insulin secretion

F-actin dynamics are known to control insulin secretion, but the point of intersection with the stimulus-secretion cascade is unknown. Here, using multiphoton imaging of β cells isolated from Lifeact-GFP transgenic mice, we show that glucose stimulation does not cause global changes in subcortical F-actin. Instead, we observe spatially discrete and transient F-actin changes around each fusing granule. This F-actin remodelling is dependent on actin nucleation and is observed for granule fusion induced by either glucose or high potassium stimulation. Using GFP-labelled proteins, we identify local enrichment of Arp3, dynamin 2 and clathrin, all occurring after granule fusion, suggesting early recruitment of an endocytic complex to the fusing granules. Block of Arp2/3 activity with drugs or shRNA inhibits F-actin coating, traps granules at the cell membrane and reduces insulin secretion. Block of formin-mediated actin nucleation also blocks F-actin coating, but has no effect on insulin secretion. We conclude that local Arp2/3-dependent actin nucleation at the sites of granule fusion plays an important role in post-fusion granule dynamics and in the regulation of insulin secretion

Existence of Ricci flows of incomplete surfaces

We prove a general existence result for instantaneously complete Ricci flows starting at an arbitrary Riemannian surface which may be incomplete and may have unbounded curvature. We give an explicit formula for the maximal existence time, and describe the asymptotic behaviour in most cases.Comment: 20 pages; updated to reflect galley proof correction

Protecting healthcare workers from COVID-19: learning from variation in practice and policy identified through a global cross-sectional survey.

AIMS: The COVID-19 pandemic presents an unprecedented burden on global healthcare systems, and existing infrastructures must adapt and evolve to meet the challenge. With health systems reliant on the health of their workforce, the importance of protection against disease transmission in healthcare workers (HCWs) is clear. This study collated responses from several countries, provided by clinicians familiar with practice in each location, to identify areas of best practice and policy so as to build consensus of those measures that might reduce the risk of transmission of COVID-19 to HCWs at work. METHODS: A cross-sectional descriptive survey was designed with ten open and closed questions and sent to a representative sample. The sample was selected on a convenience basis of 27 senior surgeons, members of an international surgical society, who were all frontline workers in the COVID-19 pandemic. This study was reported according to the Standards for Reporting Qualitative Research (SRQR) checklist. RESULTS: Responses were received by all 27 surgeons from 22 countries across six continents. A number of the study respondents reported COVID-19-related infection and mortality in HCWs in their countries. Differing areas of practice and policy were identified and organized into themes including the specification of units receiving COVID-19 patients, availability and usage of personal protective equipment (PPE), other measures to reduce staff exposure, and communicating with and supporting HCWs. Areas more specific to surgery also identified some variation in practice and policy in relation to visitors to the hospital, the outpatient department, and in the operating room for both non-urgent and emergency care. CONCLUSION: COVID-19 presents a disproportionate risk to HCWs, potentially resulting in a diminished health system capacity, and consequently an impairment to population health. Implementation of these recommendations at an international level could provide a framework to reduce this burden

Accessibility-as-a-service an open-source reading assistive tool for education

As technology evolves, more and more articles and materials are readily available on the internet for the world to use. This project proposes and demonstrates the implementation of an application to further increase the accessibility of web pages, through the use of image recognition techniques, object detection, and optical character recognition (OCR). The proposed application allows users to input URLs and the application will process the web page in under a minute and outputs a modified web page with translated words detected from images

A SAS-6-like protein suggests that the Toxoplasma conoid complex evolved from flagellar components

SAS-6 is required for centriole biogenesis in diverse eukaryotes. Here, we describe a novel family of SAS-6-like (SAS6L) proteins that share an N-terminal domain with SAS-6 but lack coiled-coil tails. SAS6L proteins are found in a subset of eukaryotes that contain SAS-6, including diverse protozoa and green algae. In the apicomplexan parasite Toxoplasma gondii, SAS-6 localizes to the centriole but SAS6L is found above the conoid, an enigmatic tubulin-containing structure found at the apex of a subset of alveolate organisms. Loss of SAS6L causes reduced fitness in Toxoplasma. The Trypanosoma brucei homolog of SAS6L localizes to the basal-plate region, the site in the axoneme where the central-pair microtubules are nucleated. When endogenous SAS6L is overexpressed in Toxoplasma tachyzoites or Trypanosoma trypomastigotes, it forms prominent filaments that extend through the cell cytoplasm, indicating that it retains a capacity to form higher-order structures despite lacking a coiled-coil domain. We conclude that although SAS6L proteins share a conserved domain with SAS-6, they are a functionally distinct family that predates the last common ancestor of eukaryotes. Moreover, the distinct localization of the SAS6L protein in Trypanosoma and Toxoplasma adds weight to the hypothesis that the conoid complex evolved from flagellar components