The relationship between talin and acetylcholine receptor clusters in Xenopus muscle cells

La fonction de la taline dans les jonctions neuro-musculaires est inconnue. On examine sa distribution dans les groupements de récepteurs à l'acétylcholine (AChR) matures et en développement dans les cellules musculaires de Xenopus, in vivo et in vitro, par immunofluorescence. La taline y est présente de manière variable, ce qui suggère qu'elle n'est pas impliquée dans l'entretien des groupements mais pourrait être impliquée dans l'assemblage des structures spécialisées présentes dans les groupements d'AChR

Predictors of Depression in Very Young Children: A Prospective Study

There have been only a few previous population-based studies of symptoms of depression in young children. There are no previous population-based studies which examine the factors which might be casually associated with depression in very young children

Spatial and temporal patterns of locally-acquired dengue transmission in Northern Queensland, Australia, 1993-2012

Background: Dengue has been a major public health concern in Australia since it re-emerged in Queensland in 1992–1993. We explored spatio-temporal characteristics of locally-acquired dengue cases in northern tropical Queensland, Australia during the period 1993–2012.Methods: Locally-acquired notified cases of dengue were collected for northern tropical Queensland from 1993 to 2012. Descriptive spatial and temporal analyses were conducted using geographic information system tools and geostatistical techniques. Results: 2,398 locally-acquired dengue cases were recorded in northern tropical Queensland during the study period. The areas affected by the dengue cases exhibited spatial and temporal variation over the study period. Notified cases of dengue occurred more frequently in autumn. Mapping of dengue by statistical local areas (census units) reveals the presence of substantial spatio-temporal variation over time and place. Statistically significant differences in dengue incidence rates among males and females (with more cases in females) (χ2 = 15.17, d.f. = 1, p<0.01). Differences were observed among age groups, but these were not statistically significant. There was a significant positive spatial autocorrelation of dengue incidence for the four sub-periods, with the Moran's I statistic ranging from 0.011 to 0.463 (p<0.01). Semi-variogram analysis and smoothed maps created from interpolation techniques indicate that the pattern of spatial autocorrelation was not homogeneous across the northern Queensland.Conclusions: Tropical areas are potential high-risk areas for mosquito-borne diseases such as dengue. This study demonstrated that the locally-acquired dengue cases have exhibited a spatial and temporal variation over the past twenty years in northern tropical Queensland, Australia. Therefore, this study provides an impetus for further investigation of clusters and risk factors in these high-risk areas

Myosin II Motor Proteins with Different Functions Determine the Fate of Lamellipodia Extension during Cell Spreading

Non-muscle cells express multiple myosin-II motor proteins myosin IIA, myosin IIB and myosin IIC transcribed from different loci in the human genome. Due to a significant homology in their sequences, these ubiquitously expressed myosin II motor proteins are believed to have overlapping cellular functions, but the mechanistic details are not elucidated. The present study uncovered a mechanism that coordinates the distinctly localized myosin IIA and myosin IIB with unexpected opposite mechanical roles in maneuvering lamellipodia extension, a critical step in the initiation of cell invasion, spreading, and migration. Myosin IIB motor protein by localizing at the front drives lamellipodia extension during cell spreading. On the other hand, myosin IIA localizes next to myosin IIB and attenuates or retracts lamellipodia extension. Myosin IIA and IIB increase cell adhesion by regulating focal contacts formation in the spreading margins and central part of the spreading cell, respectively. Spreading cells expressing both myosin IIA and myosin IIB motor proteins display an organized actin network consisting of retrograde filaments, arcs and central filaments attached to focal contacts. This organized actin network especially arcs and focal contacts formation in the spreading margins were lost in myosin IIÂ cells. Surprisingly, myosin IIB̂ cells displayed long parallel actin filaments connected to focal contacts in the spreading margins. Thus, with different roles in the regulation of the actin network and focal contacts formation, both myosin IIA and IIB determine the fate of lamellipodia extension during cell spreading

The Role of Actin Turnover in Retrograde Actin Network Flow in Neuronal Growth Cones

The balance of actin filament polymerization and depolymerization maintains a steady state network treadmill in neuronal growth cones essential for motility and guidance. Here we have investigated the connection between depolymerization and treadmilling dynamics. We show that polymerization-competent barbed ends are concentrated at the leading edge and depolymerization is distributed throughout the peripheral domain. We found a high-to-low G-actin gradient between peripheral and central domains. Inhibiting turnover with jasplakinolide collapsed this gradient and lowered leading edge barbed end density. Ultrastructural analysis showed dramatic reduction of leading edge actin filament density and filament accumulation in central regions. Live cell imaging revealed that the leading edge retracted even as retrograde actin flow rate decreased exponentially. Inhibition of myosin II activity before jasplakinolide treatment lowered baseline retrograde flow rates and prevented leading edge retraction. Myosin II activity preferentially affected filopodial bundle disassembly distinct from the global effects of jasplakinolide on network turnover. We propose that growth cone retraction following turnover inhibition resulted from the persistence of myosin II contractility even as leading edge assembly rates decreased. The buildup of actin filaments in central regions combined with monomer depletion and reduced polymerization from barbed ends suggests a mechanism for the observed exponential decay in actin retrograde flow. Our results show that growth cone motility is critically dependent on continuous disassembly of the peripheral actin network

Mindfulness in Action: Discovering How U.S. Navy Seals Build Capacity for Mindfulness in High-Reliability Organizations (HROs)

This study of US Navy Sea Air and Land (SEAL) commandos contributes to research investigating mindfulness in High-Reliability Organizations (HROs) by identifying the individual and collective influences that allow SEALs to build capacity for mindful behaviors despite the complexity of their missions, the unpredictability of their operating environments, and the danger inherent in their work. Although the HRO literature identifies a number of hallmarks of reliability, less attention is paid to how mindfulness is operationally achieved in situ by individuals on the frontline working in HROs. This study addresses this gap using a multi-phase, multi-method investigation of US Navy SEALs, identifying new links between individual mindfulness attributes (comfort with uncertainty and chaos) and collective mindfulness influences (a positive orientation towards failure) that combine to co-create a phenomenon we call 'mindfulness in action'. Mindfulness in action occurs when HROs achieve an attentive yet flexible focus capable of incorporating multiple—sometimes competing—realities in order to assess alternative solutions and take action in dynamic situations. By providing a more nuanced conceptualization of the links between individual mindfulness attributes and collective mindfulness influences, this paper opens up new avenues of discovery for a wide range of reliability-seeking organizations.This study of US Navy Sea Air and Land (SEAL) commandos contributes to research investigating mindfulness in High-Reliability Organizations (HROs) by identifying the individual and collective influences that allow SEALs to build capacity for mindful behaviors despite the complexity of their missions, the unpredictability of their operating environments, and the danger inherent in their work. Although the HRO literature identifies a number of hallmarks of reliability, less attention is paid to how mindfulness is operationally achieved in situ by individuals on the frontline working in HROs. This study addresses this gap using a multi-phase, multi-method investigation of US Navy SEALs, identifying new links between individual mindfulness attributes (comfort with uncertainty and chaos) and collective mindfulness influences (a positive orientation towards failure) that combine to co-create a phenomenon we call 'mindfulness in action'. Mindfulness in action occurs when HROs achieve an attentive yet flexible focus capable of incorporating multiple—sometimes competing—realities in order to assess alternative solutions and take action in dynamic situations. By providing a more nuanced conceptualization of the links between individual mindfulness attributes and collective mindfulness influences, this paper opens up new avenues of discovery for a wide range of reliability-seeking organizations

Lingual deficits in neurotrophin double knockout mice

Brain-derived neurotrophic factor (BDNF) and Neurotrophin 3 (NT-3) are members of the neurotrophin family and are expressed in the developing and adult tongue papillae. BDNF null-mutated mice exhibit specific impairments related to innervation and development of the gustatory system while NT-3 null mice have deficits in their lingual somatosensory innervation. To further evaluate the functional specificity of these neurotrophins in the peripheral gustatory system, we generated double BDNF/NT-3 knockout mice and compared the phenotype to BDNF −/− and wild-type mice. Taste papillae morphology was severely distorted in BDNF −/− x NT-3 −/− mice compared to single BDNF −/− and wild-type mice. The deficits were found throughout the tongue and all gustatory papillae. There was a significant loss of fungiform papillae and the papillae were smaller in size compared to BDNF −/− and wild-type mice. Circumvallate papillae in the double knockouts were smaller and did not contain any intraepithelial nerve fibers. BDNF −/− x NT-3 −/− mice exhibited additive losses in both somatosensory and gustatory innervation indicating that BDNF and NT-3 exert specific roles in the innervation of the tongue. However, the additional loss of fungiform papillae and taste buds in BDNF −/− x NT-3 −/− mice compared to single BDNF knockout mice indicate a synergistic functional role for both BDNF-dependent gustatory and NT-3-dependent somatosensory innervations in taste bud and taste papillae innervation and development.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47465/1/11068_2005_Article_3330.pd