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"Webb, Stephen"
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Uniform patchy and hollow rectangular platelet micelles from crystallizable polymer blends
The preparation of colloidally stable, self-assembled materials with tailorable solid or hollow two-dimensional (2D) structures represents a major challenge. We describe the formation of uniform, monodisperse rectangular platelet micelles of controlled size by means of seeded-growth methods that involve the addition of blends of crystalline-coil block copolymers and the corresponding crystalline homopolymer to cylindrical micelle seeds. Sequential addition of different blends yields solid platelet block comicelles with concentric rectangular patches with distinct coronal chemistries. These complex nano-objects can be subject to spatially selective processing that allows their disassembly to form perforated platelets, such as well-defined hollow rectangular rings. The solid and hollow 2D micelles provide a tunable platform for further functionalization and potential for a variety of applications.
Journal Article
Cell wall constrains lateral diffusion of plant plasma-membrane proteins
A cell membrane can be considered a liquid-phase plane in which lipids and proteins theoretically are free to diffuse. Numerous reports, however, describe retarded diffusion of membrane proteins in animal cells. This anomalous diffusion results from a combination of structuring factors including protein–protein interactions, cytoskeleton corralling, and lipid organization into microdomains. In plant cells, plasma-membrane (PM) proteins have been described as relatively immobile, but the control mechanisms that structure the PM have not been studied. Here, we use fluorescence recovery after photobleaching to estimate mobility of a set of minimal PM proteins. These proteins consist only of a PM-anchoring domain fused to a fluorescent protein, but their mobilities remained limited, as is the case for many full-length proteins. Neither the cytoskeleton nor membrane microdomain structure was involved in constraining the diffusion of these proteins. The cell wall, however, was shown to have a crucial role in immobilizing PM proteins. In addition, by single-molecule fluorescence imaging we confirmed that the pattern of cellulose deposition in the cell wall affects the trajectory and speed of PM protein diffusion. Regulation of PM protein dynamics by the plant cell wall can be interpreted as a mechanism for regulating protein interactions in processes such as trafficking and signal transduction.
Journal Article
Genetic and Morphological Approaches Distinguish the Three Sibling Species of the Anisakis simplex Species Complex, with a Species Designation as Anisakis berlandi n. sp. for A. simplex sp. C (Nematoda: Anisakidae)
Numerous specimens of the 3 sibling species of the Anisakis simplex species complex (A. pegreffii, A. simplex (senso stricto)), and A. simplex sp. C) recovered from cetacean species stranded within the known geographical ranges of these nematodes were studied morphologically and genetically. The genetic characterization was performed on diagnostic allozymes and sequences analysis of nuclear (internal transcribed spacer [ITS] of ribosomal [r]DNA) and mitochondrial (mitochondrial [mt]DNA cox2 and rrnS) genes. These markers showed (1) the occurrence of sympatry of the 2 sibling species A. pegreffii and A. simplex sp. C in the same individual host, the pilot whale, Globicephala melas Traill, from New Zealand waters; (2) the identification of specimens of A. pegreffii in the striped dolphin, Stenella coeruleoalba (Meyen), from the Mediterranean Sea; and (3) the presence of A. simplex (s.s.) in the pilot whale and the minke whale, Balaenoptera acutorostrata Lacépède, from the northeastern Atlantic waters. No F1 hybrids were detected among the 3 species using the nuclear markers. The phylogenetic inference, obtained by maximum parsimony (MP) analysis of separate nuclear (ITS rDNA region), combined mitochondrial (mtDNA cox2 and rrnS) sequences datasets, and by concatenated analysis obtained at both MP and Bayesian inference (BI) of the sequences datasets at the 3 studied genes, resulted in a similar topology. They were congruent in depicting the existence of the 3 species as distinct phylogenetic lineages, and the tree topologies support the finding that A. simplex (s.s.), A. pegreffii, and A. berlandi n. sp. (=A. simplex sp. C) represent a monophyletic group. The morphological and morphometric analyses revealed the presence of morphological features that differed among the 3 biological species. Morphological analysis using principal component analysis, and Procrustes analysis, combining morphological and genetic datasets, showed the specimens clustering into 3 well-defined groups. Nomenclatural designation and formal description are given for A. simplex species C: the name Anisakis berlandi n. sp. is proposed. Key morphological diagnostic traits are as follows between A. berlandi n. sp. and A. simplex (s.s.): ventriculus length, tail shape, tail length/total body length ratio, and left spicule length/total body length ratio; between A. berlandi n. sp. and A. pegreffii: ventriculus length and plectane 1 width/plectane 3 width ratio; and between A. simplex (s.s.) and A. pegreffii: ventriculus length, left and right spicule length/total body length ratios, and tail length/total body length ratio. Ecological data pertaining to the geographical ranges and host distribution of the 3 species are updated.
Journal Article
Perkinsus olseni and other parasites and abnormal tissue structures in New Zealand Greenshell™ mussels (Perna canaliculus) across different seasons
The New Zealand Greenshell™ mussel (Perna canaliculus) supports the largest aquaculture industry in the country. However, summer mortality events and potential disease outbreaks may threaten the growth of this industry. As an approach to gauging potential threats through the seasons, a detailed histopathological examination was conducted on 256 adult cultured mussels collected from a farm between April 2018 to September 2019, which covered the austral autumn, winter, spring and summer seasons. Histological sections followed by confirmatory in situ hybridization (ISH) resulted in the identification of Perkinsus olseni at an overall prevalence of 56%. Other parasites and pathogens were identified by histology: apicomplexan parasite X (APX) (78%), copepods (Pseudomyicola spinosus or Lichomolgus uncus) (1%), Microsporidium rapuae (1%), intracellular microcolonies of bacteria (IMCs) (2%) and bacilli and cocci bacteria (4%) in gills, mantle, gonads, digestive epithelium and digestive tubules. There was a significant association between P. olseni and APX infection in mussels. This is the first report on seasonal variations of P. olseni and APX in New Zealand Greenshell™ mussel. There was a significant association between seasons and the presence of P. olseni and APX in mussels. A significant positive association between the brown material accumulation and parasites (P. olseni and APX) and between haemocytosis and P. olseni infections were recorded. A significant association between presence of parasites and health condition (healthy and unhealthy) of mussels was observed. Moreover, a significant association between digestive tubule deterioration (large lumen, with a thin epithelial wall) and P. olseni infection was noted. Therefore, this study provides information regarding the infections of potential parasites and pathogens for the first time in P. canaliculus, their seasonal variations and host-parasite interactions within a commercial farm.
Journal Article
Derek Jarman's sketchbooks
A revealing insight into the life and method of one of the most influential filmmaking talents of the modern era. Featuring the very best excerpts from many of Jarman's rarely or never seen sketchbooks, each page is layered with drawings, photographs, cuttings, letters - even pressed flowers - and accompanied by scrawled ideas, beautifully penned poetry and working scripts.
Book
Newly Qualified Social Workers' Readiness for Practice in Scotland
Little is known about newly qualified social worker (NQSW) experiences of education, employment and training in Scotland. This article reports on findings from a national online survey (n = 205) conducted with NQSWs during their first year of employment. The study presented here was commissioned by the Scottish Social Service Council (SSSC) as part of a wider strategic review of social work education. This study used a mixed-methods design, and the results were analysed using quantitative and qualitative software. Findings indicate that the majority of NQSWs feel well prepared by social work education, but less supported by employers in terms of opportunities for continuous professional development. Experiences of good-quality induction, supervision and opportunities for professional development demonstrate mixed results across Scotland. This study has important implications for the forthcoming review of social work education in Scotland and builds on research from England and Wales. It provides empirical clarity on what NQSWs know, value and understand about their professional role and tasks. These Scottish findings run contrary to wider UK concerns that NQSWs are inadequately prepared for the challenge of child-care social work.
Journal Article