Dynamics of Dynamin during Clathrin Mediated Endocytosis in PC12 Cells

Members of the dynamin super-family of GTPases are involved in disparate cellular pathways. Dynamin1 and dynamin2 have been implicated in clathrin-mediated endocytosis. While some models suggest that dynamin functions specifically at the point of vesicle fission, evidence also exists for a role prior to fission during vesicle formation and it is unknown if there is a role for dynamin after vesicle fission. Although dynamin2 is ubiquitously expressed, dynamin1 is restricted to the nervous system. These two structurally similar endocytic accessory proteins have not been studied in cells that endogenously express both.The present study quantitatively assesses the dynamics of dynamin1 and dynamin2 during clathrin-mediated endocytosis in PC12 cells, which endogenously express both proteins. Both dynamin isoforms co-localized with clathrin and showed sharp increases in fluorescence intensity immediately prior to internalization of the nascent clathrin-coated vesicle. The fluorescence intensity of both proteins then decreased with two time constants. The slower time constant closely matched the time constant for the decrease of clathrin intensity and likely represents vesicle movement away from the membrane. The faster rate may reflect release of dynamin at the neck of nascent vesicle following GTP hydrolysis.This study analyses the role of dynamin in clathrin-mediated endocytosis in a model for cellular neuroscience and these results may provide direct evidence for the existence of two populations of dynamin associated with nascent clathrin-coated vesicles

Identification of a novel type of spacer element required for imprinting in fission yeast

Asymmetrical segregation of differentiated sister chromatids is thought to be important for cellular differentiation in higher eukaryotes. Similarly, in fission yeast, cellular differentiation involves the asymmetrical segregation of a chromosomal imprint. This imprint has been shown to consist of two ribonucleotides that are incorporated into the DNA during laggingstrand synthesis in response to a replication pause, but the underlying mechanism remains unknown. Here we present key novel discoveries important for unravelling this process. Our data show that cis-acting sequences within the mat1 cassette mediate pausing of replication forks at the proximity of the imprinting site, and the results suggest that this pause dictates specific priming at the position of imprinting in a sequence-independent manner. Also, we identify a novel type of cis-acting spacer region important for the imprinting process that affects where subsequent primers are put down after the replication fork is released from the pause. Thus, our data suggest that the imprint is formed by ligation of a not-fullyprocessed Okazaki fragment to the subsequent fragment. The presented work addresses how differentiated sister chromatids are established during DNA replication through the involvement of replication barriers

Microwave Oscillations of a Nanomagnet Driven by a Spin-Polarized Current

We describe direct electrical measurements of microwave-frequency dynamics in individual nanomagnets that are driven by spin transfer from a DC spin-polarized current. We map out the dynamical stability diagram as a function of current and magnetic field, and we show that spin transfer can produce several different types of magnetic excitations, including small-angle precession, a more complicated large-angle motion, and a high-current state that generates little microwave signal. The large-angle mode can produce a significant emission of microwave energy, as large as 40 times the Johnson-noise background.Comment: 12 pages, 3 figure

Increasing access to erectile dysfunction treatment via pharmacies to improve healthcare provider visits and quality of life: Results from a prospective real-world observational study in the United Kingdom

OBJECTIVES: The Medicines and Healthcare Products Regulatory Agency in the United Kingdom (UK) formally reclassified sildenafil citrate 50 mg tablets as a pharmacy medicine (sildenafil-P) in 2017 for adult men with erectile dysfunction (ED). A 1-year prospective real-world observational study was conducted to track men's health behaviour, particularly their healthcare resource utilisation (HCRU) and quality of life (QoL) before and after the availability of sildenafil-P. METHODS: Adult men with ED aged ≥18 years provided data at baseline (prior to launch of sildenafil-P) and every 3 months after the launch. Demographics, health characteristics, treatments at baseline and HCRU, including number of pharmacist and physician/nurse practitioner visits over time are reported. QoL-related outcomes were assessed via the Self-Esteem and Relationship Questionnaire (SEAR), 2-Item Patient Health Questionnaire and ratings of sexual satisfaction. Generalised linear models were used to assess the association of sildenafil-P use with total physician/nurse practitioner and pharmacist visits and QoL-related outcomes at 12 months. RESULTS: Overall, 1162 men completed the survey at all 5 time points. The mean ± SD age was 59.02 ± 12.06 years; 55.42% reported having a moderate-to-severe ED. Hypertension (37.52%) and hypercholesterolaemia (31.50%) were the most common risk factors for ED. At baseline, 62.99% were not using any ED treatment. After adjusting for baseline visits/other covariates, mean physician/nurse practitioner (3.68 vs 2.87; P = .003) and pharmacist visits for any reason (2.10 vs 1.34; P < .001) at 12 months were significantly higher among sildenafil-P users than those who never used sildenafil-P. Sildenafil-P users also had significantly higher SEAR total and domain (sexual relationship and self-esteem) scores at 12 months. CONCLUSION: Following the reclassification to a pharmacy medicine in the UK, sildenafil-P was associated with a higher number of physician/nurse practitioner and pharmacist visits for any reason. Sildenafil-P use was also associated with better QoL, although group differences were small in magnitude

A new linear magnetic gear with adjustable gear ratios and its application for direct-drive wave energy extraction

In this paper, a new linear magnetic gear with multiple gear ratios is proposed. Unlike the conventional linear magnetic gears, the proposed one purposely utilizes the aluminum-nickel-cobalt (AlNiCo) permanent magnets (PMs) as the excitation source. Due to the relatively low coercivity, AlNiCo PMs can be magnetized or demagnetized by applying an appropriate DC current pulse into the magnetizing winding. Thus, the pole-pair numbers of PMs on two movers can be varied accordingly so that different gear ratios can be achieved. Firstly, the mathematical modeling of the hysteresis loop of AlNiCo PMs is established. Then, the proposed linear magnetic gear with adjustable gear ratios is presented. Instead of the traditional surface-mounted PM configuration, the proposed machine installs the PMs using the surface-inset and consequent-pole configuration. Hence, the adverse influence during the magnetizing or demagnetizing process can be minimized. Since the magnetizing windings are placed in the movers, no position control is required for the magnetizing or demagnetizing process. By applying finite element analysis, the electromagnetic performances of the proposed linear magnetic gear with adjustable gear ratios are evaluated. Finally, the proposed linear magnetic gear is applied for direct-drive wave energy extraction. Owing to the capability of adjustable gear ratios, the wave energy converter can be operated in resonance with the waves at different sea states so that the maximized power can be captured

A systematic review of the effectiveness of qigong exercise in supportive cancer care

PURPOSE: Qigong as a complementary and alternative modality of traditional Chinese medicine is often used by cancer patients to manage their symptoms. The aim of this systematic review is to critically evaluate the effectiveness of qigong exercise in cancer care. METHODS: Thirteen databases were searched from their inceptions through November 2010. All controlled clinical trials of qigong exercise among cancer patients were included. The strength of the evidence was evaluated for all included studies using the Oxford Centre for Evidence-based Medicine Levels of Evidence. The validity of randomized controlled trials (RCTs) was also evaluated using the Jadad Scale. RESULTS: Twenty-three studies including eight RCTs and fifteen non-randomized controlled clinical trials (CCTs) were identified. The effects of qigong on physical and psychosocial outcomes were examined in 14 studies and the effects on biomedical outcomes were examined in 15 studies. For physical and psychosocial outcomes, it is difficult to draw a conclusion due to heterogeneity of outcome measures and variability of the results in the included studies. Among reviewed studies on biomedical outcomes, a consistent tendency appears to emerge which suggests that the patients treated with qigong exercise in combination with conventional methods had significant improvement in immune function than the patients treated with conventional methods alone. CONCLUSIONS: Due to high risk of bias and methodological problems in the majority of included studies, it is still too early to draw conclusive statements. Further vigorously designed large-scale RCTs with validated outcome measures are needed.published_or_final_versio

A Novel, “Double-Clamp” Binding Mode for Human Heme Oxygenase-1 Inhibition

The development of heme oxygenase (HO) inhibitors is critical in dissecting and understanding the HO system and for potential therapeutic applications. We have established a program to design and optimize HO inhibitors using structure-activity relationships in conjunction with X-ray crystallographic analyses. One of our previous complex crystal structures revealed a putative secondary hydrophobic binding pocket which could be exploited for a new design strategy by introducing a functional group that would fit into this potential site. To test this hypothesis and gain further insights into the structural basis of inhibitor binding, we have synthesized and characterized 1-(1H-imidazol-1-yl)-4,4-diphenyl-2-butanone (QC-308). Using a carbon monoxide (CO) formation assay on rat spleen microsomes, the compound was found to be ∼15 times more potent (IC50 = 0.27±0.07 µM) than its monophenyl analogue, which is already a potent compound in its own right (QC-65; IC50 = 4.0±1.8 µM). The crystal structure of hHO-1 with QC-308 revealed that the second phenyl group in the western region of the compound is indeed accommodated by a definitive secondary proximal hydrophobic pocket. Thus, the two phenyl moieties are each stabilized by distinct hydrophobic pockets. This “double-clamp” binding offers additional inhibitor stabilization and provides a new route for improvement of human heme oxygenase inhibitors

Thermal stress induces glycolytic beige fat formation via a myogenic state.

Environmental cues profoundly affect cellular plasticity in multicellular organisms. For instance, exercise promotes a glycolytic-to-oxidative fibre-type switch in skeletal muscle, and cold acclimation induces beige adipocyte biogenesis in adipose tissue. However, the molecular mechanisms by which physiological or pathological cues evoke developmental plasticity remain incompletely understood. Here we report a type of beige adipocyte that has a critical role in chronic cold adaptation in the absence of β-adrenergic receptor signalling. This beige fat is distinct from conventional beige fat with respect to developmental origin and regulation, and displays enhanced glucose oxidation. We therefore refer to it as glycolytic beige fat. Mechanistically, we identify GA-binding protein α as a regulator of glycolytic beige adipocyte differentiation through a myogenic intermediate. Our study reveals a non-canonical adaptive mechanism by which thermal stress induces progenitor cell plasticity and recruits a distinct form of thermogenic cell that is required for energy homeostasis and survival