92 research outputs found

    Fate specification and tissue-specific cell cycle control of the <i>Caenorhabditis elegans</i> intestine

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    Coordination between cell fate specification and cell cycle control in multicellular organisms is essential to regulate cell numbers in tissues and organs during development, and its failure may lead to oncogenesis. In mammalian cells, as part of a general cell cycle checkpoint mechanism, the F-box protein β-transducin repeat-containing protein (β-TrCP) and the Skp1/Cul1/F-box complex control the periodic cell cycle fluctuations in abundance of the CDC25A and B phosphatases. Here, we find that the Caenorhabditis elegans β-TrCP orthologue LIN-23 regulates a progressive decline of CDC-25.1 abundance over several embryonic cell cycles and specifies cell number of one tissue, the embryonic intestine. The negative regulation of CDC-25.1 abundance by LIN-23 may be developmentally controlled because CDC-25.1 accumulates over time within the developing germline, where LIN-23 is also present. Concurrent with the destabilization of CDC-25.1, LIN-23 displays a spatially dynamic behavior in the embryo, periodically entering a nuclear compartment where CDC-25.1 is abundant

    Degradation of Cdc25A by \u3b2-TrCP during S phase and in response to DNA damage

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    The Cdc25A phosphatase is essential for cell-cycle progression because of its function in dephosphorylating cyclin-dependent kinases. In response to DNA damage or stalled replication, the ATM and ATR protein kinases activate the checkpoint kinases Chk1 and Chk2, which leads to hyperphosphorylation of Cdc25A1\u20133. These events stimulate the ubiquitin-mediated pro- teolysis of Cdc25A1,4,5 and contribute to delaying cell-cycle progression, thereby preventing genomic instability1\u20137. Here we report that b-TrCP is the F-box protein that targets phosphory- lated Cdc25A for degradation by the Skp1/Cul1/F-box protein complex. Downregulation of b-TrCP1 and b-TrCP2 expression by short interfering RNAs causes an accumulation of Cdc25A in cells progressing through S phase and prevents the degradation of Cdc25A induced by ionizing radiation, indicating that b-TrCP may function in the intra-S-phase checkpoint. Consistent with this hypothesis, suppression of b-TrCP expression results in radioresistant DNA synthesis in response to DNA damage\u2014a phenotype indicative of a defect in the intra-S-phase checkpoint that is associated with an inability to regulate Cdc25A properly. Our results show that b-TrCP has a crucial role in mediating the response to DNA damage through Cdc25A degradation

    Nurses' experiences of communicating respect to patients: Influences and challenges

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    A qualitative study utilizing Interpretive Phenomenological Analysis of a sample of nursing interviews to explore the ways in which respect is conceptualized and communicated to patients.Background: Respectful care is central to ethical codes of practice and optimal patient care, but little is known about the influences on and challenges in communicating respect. Research question: What are the intra- and inter-personal influences on nurses’ communication of respect? Research design and participants: Semi-structured interviews with 12 hospital-based UK registered nurses were analysed using interpretative phenomenological analysis to explore their experiences of communicating respect to patients and associated influences. Ethical considerations: The study was approved by the Institutional ethics board and National Health Service Trust. Findings: Three interconnected superordinate themes were identified: ‘private self: personal attitudes’, ‘outward self: showing respect’ and ‘reputational self: being perceived as respectful’. Respectful communication involved a complex set of influences, including attitudes of respect towards patients, needs and goals, beliefs around the nature of respectful communication, skills and influencing sociocultural factors. A tension between the outward self as intended and perceived presented challenges for nurses’ reputational self as respectful, with negative implications for patient care. Discussion: The study offers an in-depth understanding of intra- and inter-personal influences on communicating respect, and sheds light on challenges involved, helping provide practical insights to support respectful care. Conclusion: Findings stress the need for improved conceptualisations of respect in healthcare settings to formally recognise the complex attitudinal and socially constructed nature of respect and for appropriate professional training to improve its communicatio

    The Warden Attitude: An investigation of the value of interaction with everyday wildlife

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    Using a discrete choice experiment, we elicit valuations of engagement with ‘everyday wildlife’ through feeding garden birds. We find that bird-feeding is primarily but not exclusively motivated by the direct consumption value of interaction with wildlife. The implicit valuations given to different species suggest that people prefer birds that have aesthetic appeal and that evoke human feelings of protectiveness. These findings suggest that people derive wellbeing by adopting a warden-like role towards ‘their’ wildlife. We test for external validity by conducting a hedonic analysis of sales of bird food. We discuss some policy implications of the existence of warden attitudes

    How can Respectfulness in Medical Professionals be Increased? A Complex but Important Question.

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    Respectfulness is demanded of doctors and predicts more positive patient health-related outcomes but research is scarce on ways to promote it. This study explores two ways to conceptualize unconditional respect from medical students, defined as respect paid to people on the basis of their humanity, in order to inform strategies to increase it. Unconditional respect conceptualized as an attitude suggests that unconditional respect and conditional respect are additive, whereas unconditional respect conceptualized as a personality trait suggests that people who are high on unconditional respect afford equal respect to all humans regardless of their merits. One-hundred and eighty one medical students completed an unconditional respect measure then read a description of a respect-worthy or a non-respect-worthy man and indicated their respect towards him. The study found a main effect for unconditional respect and a main effect for target respect-worthiness but no interaction between the two when respect paid to the target was assessed, supporting the attitude-based conceptualization. This suggests that unconditional respect can be increased through relevant interventions aimed at increasing the relative salience to doctors of the human worth of individuals. Interventions to increase unconditional respect are discussed

    Killer whale genomes reveal a complex history of recurrent admixture and vicariance

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    Reconstruction of the demographic and evolutionary history of populations assuming a consensus tree‐like relationship can mask more complex scenarios, which are prevalent in nature. An emerging genomic toolset, which has been most comprehensively harnessed in the reconstruction of human evolutionary history, enables molecular ecologists to elucidate complex population histories. Killer whales have limited extrinsic barriers to dispersal and have radiated globally, and are therefore a good candidate model for the application of such tools. Here, we analyse a global data set of killer whale genomes in a rare attempt to elucidate global population structure in a nonhuman species. We identify a pattern of genetic homogenisation at lower latitudes and the greatest differentiation at high latitudes, even between currently sympatric lineages. The processes underlying the major axis of structure include high drift at the edge of species' range, likely associated with founder effects and allelic surfing during postglacial range expansion. Divergence between Antarctic and non‐Antarctic lineages is further driven by ancestry segments with up to fourfold older coalescence time than the genome‐wide average; relicts of a previous vicariance during an earlier glacial cycle. Our study further underpins that episodic gene flow is ubiquitous in natural populations, and can occur across great distances and after substantial periods of isolation between populations. Thus, understanding the evolutionary history of a species requires comprehensive geographic sampling and genome‐wide data to sample the variation in ancestry within individuals

    Buses, cars, bicycles and walkers the influence of the type of human transport on the flight responses of waterbirds

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    One way to manage disturbance to waterbirds in natural areas where humans require access is to promote the occurrence of stimuli for which birds tolerate closer approaches, and so cause fewer responses. We conducted 730 experimental approaches to 39 species of waterbird, using five stimulus types (single walker, three walkers, bicycle, car and bus) selected to mimic different human management options available for a controlled access, Ramsar-listed wetland. Across species, where differences existed (56% of 25 cases), motor vehicles always evoked shorter flight-initiation distances (FID) than humans on foot. The influence of stimulus type on FID varied across four species for which enough data were available for complete cross-stimulus analysis. All four varied FID in relation to stimuli, differing in 4 to 7 of 10 possible comparisons. Where differences occurred, the effect size was generally modest, suggesting that managing stimulus type (e.g. by requiring people to use vehicles) may have species-specific, modest benefits, at least for the waterbirds we studied. However, different stimulus types have different capacities to reduce the frequency of disturbance (i.e. by carrying more people) and vary in their capacity to travel around important habita
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