RGD-containing peptides inhibit the synthesis of myelin-like membrane by cultured oligodendrocytes.

Abstract. A synthetic peptide derived from the fibronectin cell-binding domain, GRGDSP, inhibits the adhesion of rat oligodendrocytes to a number of substrates. However, while GRGDSP inhibited the adhesion of cells in a short term adhesion assay, the presence of the peptide did not prevent cells from adhering and thriving in longer term culture. The morphological characteristics of individual cells cultured with 0.1 mg/ml GRGDSP were similar to untreated cultures; small rounded cell bodies radiating numerous fine processes. Peptide-treated cultures were inhibited in their ability to produce myelin specific components. The characteristic developmental peak in sulfolipid synthesis which occurs both in vivo and in vitro was completely inhibited when cells were cultured wit

The Social context of motorcycle riding and the key determinants influencing rider behavior: A qualitative investigation

Objective: Given the increasing popularity of motorcycle riding and heightened risk of injury or death associated with being a rider, this study explored rider behaviour as a determinant of rider safety and, in particular, key beliefs and motivations which influence such behaviour. To enhance the effectiveness of future education and training interventions, it is important to understand riders’ own views about what influences how they ride. Specifically, this study sought to identify key determinants of riders’ behaviour in relation to the social context of riding including social and identity-related influences relating to the group (group norms and group identity) as well as the self (moral/personal norm and self-identity). ----- ----- Method: Qualitative research was undertaken via group discussions with motorcycle riders (n = 41). Results: The findings revealed that those in the group with which one rides represent an important source of social influence. Also, the motorcyclist (group) identity was associated with a range of beliefs, expectations, and behaviours considered to be normative. Exploration of the construct of personal norm revealed that riders were most cognizant of the “wrong things to do” when riding; among those issues raised was the importance of protective clothing (albeit for the protection of others and, in particular, pillion passengers). Finally, self-identity as a motorcyclist appeared to be important to a rider’s self-concept and was likely to influence their on-road behaviour. ----- ----- Conclusion: Overall, the insight provided by the current study may facilitate the development of interventions including rider training as well as public education and mass media messages. The findings suggest that these interventions should incorporate factors associated with the social nature of riding in order to best align it with some of the key beliefs and motivations underpinning riders’ on-road behaviours

Dust-driven Dynamos in Accretion Disks

Magnetically driven astrophysical jets are related to accretion and involve toroidal magnetic field pressure inflating poloidal magnetic field flux surfaces. Examination of particle motion in combined gravitational and magnetic fields shows that these astrophysical jet toroidal and poloidal magnetic fields can be powered by the gravitational energy liberated by accreting dust grains that have become positively charged by emitting photo-electrons. Because a dust grain experiences magnetic forces after becoming charged, but not before, charging can cause irreversible trapping of the grain so dust accretion is a consequence of charging. Furthermore, charging causes canonical angular momentum to replace mechanical angular momentum as the relevant constant of the motion. The resulting effective potential has three distinct classes of accreting particles distinguished by canonical angular momentum, namely (i) "cyclotron-orbit", (ii) "Speiser-orbit", and (iii) "zero canonical angular momentum" particles. Electrons and ions are of class (i) but depending on mass and initial orbit inclination, dust grains can be of any class. Light-weight dust grains develop class (i) orbits such that the grains are confined to nested poloidal flux surfaces, whereas grains with a critical weight such that they experience comparable gravitational and magnetic forces can develop class (ii) or class (iii) orbits, respectively producing poloidal and toroidal field dynamos.Comment: 70 pages, 16 figure

Morphological and heartwood variation of Santalum macgregorii in Papua New Guinea

© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Santalum macgregorii (sandalwood), which is endemic to the southern part of Papua New Guinea (PNG), has been heavily exploited for its fragrant heartwood and is classified as threatened across its natural range. Domestication and smallholder agroforestry offer the means to preserve remaining diversity. This study was undertaken to understand the extent of remaining natural variation to support the species’s conservation and domestication. We evaluated morphological, heartwood and essential oil characters in 126 S. macgregorii trees in five populations (districts) in PNG’s Central, Gulf and Western provinces. The heartwood oil of this species is characterised by extreme tree-to-tree variation in key fragrant compounds. Proportions of individual compounds range from negligible to high for (Z)-α-santalol (0.5–51%), (Z)-β-santalol (0–24.2%), (Z)-nuciferol (0–40.5%) and (Z)-lanceol (0–72%). Despite the wide variation found within populations, an ordination of seven oil constituents revealed broad provenance-based variation in which trees from the eastern provinces (i.e. Central and Gulf) were more influenced by (Z)-nuciferol content and the trees from the Western Province site were more strongly influenced by (Z)-lanceol. The driver of this variation was the different associations between oil constituents, with (Z)-α- and (Z)-β-santalol both negatively correlated with (Z)-nuciferol for sites in the eastern provinces and (Z)-lanceol in Western Province. No evidence of distinct chemotypes was found, with continuous variation demonstrated across all major oil constituents. Of the trees surveyed with a basal diameter of \u3e 10 cm, 79% had heartwood. Mean heartwood percentage was 15.8% of basal area, with no significant differences between sites. Significant tree-to-tree variation in heartwood percentage (0–61%) was found. A modest positive correlation was found between stem and heartwood diameter (r = 0.39). Heartwood percentage and heartwood oil quality varied independently and, therefore, independent selection of these traits may be required for their simultaneous improvement. The population in Western Province is non-contiguous with those in the eastern part of the species distribution. It also has a distinct phenotype based on oil composition, leaf shape, flower colour and potential reproductive failure. It is possible that sandalwood in Western Province is more closely related to the proximal populations of S. lanceolatum in Cape York Peninsula, Queensland, than the more distant populations of S. macgregorii in PNG. While these phenotypic features do not necessarily discriminate a new species, molecular genetic research is required to determine the potential existence of a cryptic species of sandalwood. The implications of the variation found in S. macgregorii are discussed with respect to its domestication and conservation

The NBD-NBD interface is not the sole determinant for transport in ABC transporters

International audienceOne of the most exciting scientific challenges in functional genomics concerns the discovery of biologically relevant patterns from gene expression data. For instance, it is extremely useful to provide putative synexpression groups or transcription modules to molecular biologists. We propose a methodology that has been proved useful in real cases. It is described as a prototypical KDD scenario which starts from raw expression data selection until useful patterns are delivered. Our conceptual contribution is (a) to emphasize how to take the most from recent progress in constraint-based mining of set patterns, and (b) to propose a generic approach for gene expression data enrichment. The methodology has been validated on real data sets

Association of Shank 1A Scaffolding Protein with Cone Photoreceptor Terminals in the Mammalian Retina

Photoreceptor terminals contain post-synaptic density (PSD) proteins e.g., PSD-95/PSD-93, but their role at photoreceptor synapses is not known. PSDs are generally restricted to post-synaptic boutons in central neurons and form scaffolding with multiple proteins that have structural and functional roles in neuronal signaling. The Shank family of proteins (Shank 1–3) functions as putative anchoring proteins for PSDs and is involved in the organization of cytoskeletal/signaling complexes in neurons. Specifically, Shank 1 is restricted to neurons and interacts with both receptors and signaling molecules at central neurons to regulate plasticity. However, it is not known whether Shank 1 is expressed at photoreceptor terminals. In this study we have investigated Shank 1A localization in the outer retina at photoreceptor terminals. We find that Shank 1A is expressed presynaptically in cone pedicles, but not rod spherules, and it is absent from mice in which the Shank 1 gene is deleted. Shank 1A co-localizes with PSD-95, peanut agglutinin, a marker of cone terminals, and glycogen phosphorylase, a cone specific marker. These findings provide convincing evidence for Shank 1A expression in both the inner and outer plexiform layers, and indicate a potential role for PSD-95/Shank 1 complexes at cone synapses in the outer retina.National Institutes of Health (U.S.) (K08 Award NS41411)Howard Hughes Medical Institute (Investigator

Reducing drug related deaths : a pre-implementation assessment of knowledge,barriers and enablers for naloxone distribution through general practice

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