Kinesin-5 motors are required for organization of spindle microtubules in Silvetia compressa zygotes

BACKGROUND: Monastrol, a chemical inhibitor specific to the Kinesin-5 family of motor proteins, was used to examine the functional roles of Kinesin-5 proteins during the first, asymmetric cell division cycle in the brown alga Silvetia compressa. RESULTS: Monastrol treatment had no effect on developing zygotes prior to entry into mitosis. After mitosis entry, monastrol treatment led to formation of monasters and cell cycle arrest in a dose dependent fashion. These findings indicate that Kinesin-5 motors maintain spindle bipolarity, and are consistent with reports in animal cells. At low drug concentrations that permitted cell division, spindle position was highly displaced from normal, resulting in abnormal division planes. Strikingly, application of monastrol also led to formation of numerous cytasters throughout the cytoplasm and multipolar spindles, uncovering a novel effect of monastrol treatment not observed in animal cells. CONCLUSION: We postulate that monastrol treatment causes spindle poles to break apart forming cytasters, some of which capture chromosomes and become supernumerary spindle poles. Thus, in addition to maintaining spindle bipolarity, Kinesin-5 members in S. compressa likely organize microtubules at spindle poles. To our knowledge, this is the first functional characterization of the Kinesin-5 family in stramenopiles

Localization and function of Kinesin-5-like proteins during assembly and maintenance of mitotic spindles in Silvetia compressa

<p>Abstract</p> <p>Background</p> <p>Kinesin-5 (Eg-5) motor proteins are essential for maintenance of spindle bipolarity in animals. The roles of Kinesin-5 proteins in other systems, such as Arabidopsis, Dictyostelium, and sea urchin are more varied. We are studying Kinesin-5-like proteins during early development in the brown alga <it>Silvetia compressa</it>. Previously, this motor was shown to be needed to assemble a bipolar spindle, similar to animals. This report builds on those findings by investigating the localization of the motor and probing its function in spindle maintenance.</p> <p>Findings</p> <p>Anti-Eg5 antibodies were used to investigate localization of Kinesin-5-like proteins in brown algal zygotes. In interphase zygotes, localization was predominantly within the nucleus. As zygotes entered mitosis, these motor proteins strongly associated with spindle poles and, to a lesser degree, with the polar microtubule arrays and the spindle midzone. In order to address whether Kinesin-5-like proteins are required to maintain spindle bipolarity, we applied monastrol to synchronized zygotes containing bipolar spindles. Monastrol is a cell-permeable chemical inhibitor of the Kinesin-5 class of molecular motors. We found that inhibition of motor function in pre-formed spindles induced the formation of multipolar spindles and short bipolar spindles.</p> <p>Conclusion</p> <p>Based upon these localization and inhibitor studies, we conclude that Kinesin-5-like motors in brown algae are more similar to the motors of animals than those of plants or protists. However, Kinesin-5-like proteins in <it>S. compressa </it>serve novel roles in spindle formation and maintenance not observed in animals.</p

Independent and Combined Effects of Menhaden Oil and High Fructose on Hepatic Lipid Metabolism

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The Lipogenic Effect of High-Fructose Consumption on NAFLD During Weight Loss

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The COMMAND trial of cognitive therapy for harmful compliance with command hallucinations (CTCH) : a qualitative study of acceptability and tolerability in the UK

Objectives To explore service user experiences of a 9-month cognitive behavioural therapy for command hallucinations in the context of a randomised controlled trial including their views on acceptability and tolerability of the intervention. Design Qualitative study using semistructured interviews. Setting The study took place across three sites: Birmingham, Manchester and London. Interviews were carried out at the sites where therapy took place which included service bases and participants’ homes. Participants Of 197 patients who consented to the trial, 98 received the Cognitive Behavior Therapy for Command Hallucinations (CTCH) intervention; 25 (15 males) of whom were randomly selected and consented to the qualitative study. The mean age of the sample was 42 years, and 68% were white British. Results Two superordinate themes were identified: participants’ views about the aspects of CTCH they found most helpful; and participants’ concerns with therapy. Helpful aspects of the therapy included gaining control over the voices, challenging the power and omniscience of the voices, following a structured approach, normalisation and mainstreaming of the experience of voices, and having peer support alongside the therapy. Concerns with the therapy included anxiety about completing CTCH tasks, fear of talking back to voices, the need for follow-up and ongoing support and concerns with adaptability of the therapy. Conclusions Interpretation: CTCH was generally well received and the narratives validated the overall approach. Participants did not find it an easy therapy to undertake as they were challenging a persecutor they believed had great power to harm; many were concerned, anxious and occasionally disappointed that the voices did not disappear altogether. The trusting relationship with the therapist was crucial. The need for continued support was expressed

A core outcome set for randomised controlled trials of physical activity interventions: development and challenges.

BACKGROUND: Core outcome sets are standardised sets of outcomes that should be collected and reported for all clinical trials. They have been widely developed and are increasingly influential in clinical research, but despite this, their use in public health has been limited to date. The aim of this study was to develop a core outcome set for public health trials evaluating interventions to promote physical activity in the general adult population. METHODS: The core outcome set was developed using a three-stage approach: stage one: a review of literature to identify potential domains for inclusion in the core outcome set; stage two: a Delphi survey was carried out to reach consensus about which outcome domains to include in the core outcome set; and stage three: a second Delphi survey was conducted to determine how best to measure the outcome domains included in the core outcome set. RESULTS: A classification of 13 outcome domains of physical activity was developed (stage one). Twenty people completed round one of the first Delphi survey (stage two), reaching a consensus to include two domains in the core outcome set, 'device-based level of physical activity' (80.0%, n = 16) and 'health-related quality of life' (70.0%, n = 14). No further consensus on the remaining outcome domains was reached in round two. Nineteen people completed the second Delphi survey (stage three). Participants rated the accelerometer (mean rating = 3.89, on a scale of 1 (do not recommend) to 5 (highly recommend)) as the best device to measure level of physical activity, and the EQ-5D (73.7%, n = 14) as the most appropriate measure of health-related quality of life. CONCLUSIONS: This study has made progress towards the development of a core outcome set for use in physical activity trials, however, there was limited consensus about which domains to include. The development of the core outcome set was challenged by the need for trial-specific outcomes, and the complexities of collecting, processing and reporting device-based data

Transmission of pandemic A/H1N1 2009 influenza on passenger aircraft: retrospective cohort study

Objectives To assess the risk of transmission of pandemic A/H1N1 2009 influenza (pandemic A/H1N1) from an infected high school group to other passengers on an airline flight and the effectiveness of screening and follow-up of exposed passengers