91 research outputs found

    Endocytic pathways: combined scanning ion conductance and surface confocal microscopy study

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    We introduce a novel high resolution scanning surface confocal microscopy technique that enables imaging of endocytic pits in apical membranes of live cells for the first time. The improved topographical resolution of the microscope together with simultaneous fluorescence confocal detection produces pairs of images of cell surfaces sufficient to identify single endocytic pits. Whilst the precise position and size of the pit is detected by the ion conductance microscope, the molecular nature of the pit, e.g. clathrin coated or caveolae, is determined by the corresponding green fluorescent protein fluorescence. Also, for the first time, we showed that flotillin 1 and 2 can be found co-localising with ~200-nm indentations in the cell membrane that supports involvement of this protein in endocytosis

    Supramolecular metallomacrocycles based on trans-dicyanoferrite(III) building blocks: synthesis, crystal structure and magnetic properties

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    The reaction of trans-[Fe(R-bpb)(CN)(2)](-) (R-bpb(2-)= R-substituted-1,2-bis(pyridine-2-carboxamido)benzenate) with trans-Mn(III) Schiff base complexes [Mn(5-X-saltn)]ClO4 (5-X-saltn(2-) = N,N'-propanolbis(5-X-substituted-salcylideneiminato) dianion) gave rise to cyanide-bridged neutral binuclear [MnFe] compounds [Mn(saltn)(MeOH)][Fe(bpb)(CN)(2)]center dot 3H(2)O ( 1), [Mn(saltn)(H2O)Fe(bpmb)(CN)(2)] center dot H2O (2), [Mn(saltn)(MeOH)Fe(bpClb)(CN)(2)]center dot 2H(2)O ( 3), and ionic [Mn2Fe](+)-[Fe](-) complexes [Mn-2(5-Br-saltn)(2)(H2O)(EtOH)Fe(bpb)(CN)(2)][Fe(bpb)(CN)(2)]center dot 6H(2)O ( 4) and [Mn-2(5-Cl-saltn)(2)(CH3OH)(EtOH)Fe(bpb)(CN)(2)][Fe(bpb)(CN)(2)]center dot 5H(2)O center dot MeCN (5). Four binuclear units of complexes 1-3 assemble in a head-to-tail way via hydrogen bonding giving rise to a metallo-supramolecular [MnFe](4) square, while two [Mn2Fe](+)-[Fe](-) units of complexes 4-5 form a metallo-supramolecular macrocyclic structure. Magnetic studies reveal that complexes 1-3 and 5 exhibit intermetallic ferromagnetic coupling, while complex 4 displays antiferromagnetic interaction between low-spin Fe(III) and high-spin Mn(III) through the cyanide bridges. Complexes 1, 4 and 5 display frequency dependent of current-alternating (ac) magnetic susceptibility, typical of the presence of slow magnetization relaxation. Because of the existence of intermolecular magnetic interaction, complex 4 shows an exchange-biased single-molecule magnet (SMM) behavior below 0.5 K.Natural Science Foundation of China [20671055, 50873053]; Program for New Century Excellent Talents in Universit

    Hystricognathy vs Sciurognathy in the Rodent Jaw: A New Morphometric Assessment of Hystricognathy Applied to the Living Fossil Laonastes (Diatomyidae)

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    While exceptional for an intense diversification of lineages, the evolutionary history of the order Rodentia comprises only a limited number of morphological morphotypes for the mandible. This situation could partly explain the intense debates about the taxonomic position of the latest described member of this clade, the Laotian rock rat Laonastes aenigmamus (Diatomyidae). This discovery has re-launched the debate on the definition of the Hystricognathi suborder identified using the angle of the jaw relative to the plane of the incisors. Our study aims to end this ambiguity. For clarity, it became necessary to revisit the entire morphological diversity of the mandible in extant and extinct rodents. However, current and past rodent diversity brings out the limitations of the qualitative descriptive approach and highlights the need for a quantitative approach. Here, we present the first descriptive comparison of the masticatory apparatus within the Ctenohystrica clade, in combining classic comparative anatomy with morphometrical methods. First, we quantified the shape of the mandible in rodents using 3D landmarks. Then, the analysis of osteological features was compared to myological features in order to understand the biomechanical origin of this morphological diversity. Among the morphological variation observed, the mandible of Laonastes aenigmamus displays an intermediate association of features that could be considered neither as sciurognathous nor as hystricognathous

    Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

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    In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

    Combinatorial structure and iconicity in artificial whistled languages

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    This article reports on an experiment in which artificial languages with whistle words for novel objects are culturally transmitted in the laboratory. The aim of this study is to investigate the origins and evolution of combinatorial structure in speech. Participants learned the whistled language and reproduced the sounds with the use of a slide whistle. Their reproductions were used as input for the next participant. Cultural transmission caused the whistled systems to become more learnable and more structured. In addition, two conditions were studied: one in which the use of iconic form-meaning mappings was possible and one in which the use of iconic mappings was experimentally made impossible, so that we could investigate the influence of iconicity on the emergence of structure

    xyluo25/grid2demand: v0.3.9-rc.1

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    <p>This release enables the loading of TAZs to generate zones.</p&gt

    Inferring specifications to detect errors in code

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    Abstract. A new technique is presented to statically check a given procedure against a user-provided property. The method requires no annotations; it automatically infers a context-dependent specification for each procedure call, so that only as much information about a procedure is used as is needed to analyze its caller. Specifications are inferred iteratively. Empty specifications are initially used to overapproximate the effects of all procedure calls; these are later refined in response to spurious counterexamples. When the analysis terminates, any remaining counterexample is guaranteed to be valid. However, since the heap is finitized, the absence of a counterexample does not guarantee the validity of the given property. 1
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