2,815 research outputs found

    Thermal imprinting modifies adult stress and innate immune responsiveness in the teleost sea bream

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    The impact of thermal imprinting on the plasticity of the hypothalamic-pituitary-interrenal (HPI) axis and stress response in an adult ectotherm, the gilthead sea bream (Sparus aurata, L.), during its development was assessed. Fish were reared under 4 thermal regimes, and the resulting adults exposed to acute confinement stress and plasma cortisol levels and genes of the HPI axis were monitored. Changes in immune function, a common result of stress, were also evaluated using histomorphometric measurements of melanomacrophages centers (MMCs) in the head kidney and by monitoring macrophage-related transcripts. Thermal history significantly modified the HPI responsiveness in adult sea bream when eggs and larvae were reared at a higher than optimal temperature (HT, 22 degrees C), and they had a reduced amplitude in their cortisol response and significantly upregulated pituitary pomc and head kidney star transcripts. Additionally, after an acute stress challenge, immune function was modified and the head kidney of adult fish reared during development at high temperatures (HT and LHT, 18-22 degrees C) had a decreased number of MMCs and a significant downregulation of dopachrome tautomerase. Thermal imprinting during development influenced adult sea bream physiology and increased plasma levels of glucose and sodium even in the absence of an acute stress in fish reared under a high-low thermal regime (HLT, 22-18 degrees C). Overall, the results demonstrate that temperature during early development influences the adult HPI axis and immune function in a teleost fish.project Lifecycle EU-FP7 [222719]FCT- Foundation for Science and Technology [CCMAR/Multi/04326/2013]info:eu-repo/semantics/publishedVersio

    Two Decades Of Pelagic Ecology Of The Western Antarctic Peninsula

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    Significant strides in our understanding of the marine pelagic ecosystem of the Western Antarctic Peninsula (WAP) region have been made over the past two decades, resulting from research conducted aboard ARSV Laurence M. Gould and RVIB Nathaniel B. Palmer. These advances range from an understanding of the physical forcing on biology, to food web ecology (from microbes to top predators), to biogeochemical cycling, often in the larger context of rapid climate warming in the region. The proximity of the WAP to the Antarctic Circumpolar Current and WAP continental shelf bathymetry affects the hydrography and helps structure the biological community. Seasonal, spatial, and interannual variability at all levels of the food web, as well as the mechanisms supporting their production, are now more clearly understood. New tools and technologies employed in the region were critical for making this research possible. As a result, our knowledge of the WAP pelagic ecosystem during a time of rapid climate change has vastly improved

    Evolution of the angiopoietin-like gene family in teleosts and their role in skin regeneration

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    Background The skin in vertebrates is a protective barrier and damage is rapidly repaired to re-establish barrier function and maintain internal homeostasis. The angiopoietin-like (ANGPTL) proteins are a family of eight secreted glycoproteins with an important role in skin repair and angiogenesis in humans. In other vertebrates their existence and role in skin remains largely unstudied. The present study characterizes for the first time the homologues of human ANGPTLs in fish and identifies the candidates that share a conserved role in skin repair using a regenerating teleost skin model over a 4-day healing period. Results Homologues of human ANGPTL1-7 were identified in fish, although ANGPTL8 was absent and a totally new family member designated angptl9 was identified in fish and other non-mammalian vertebrates. In the teleost fishes a gene family expansion occurred but all the deduced Angptl proteins retained conserved sequence and structure motifs with the human homologues. In sea bream skin angptl1b, angptl2b, angptl4a, angptl4b and angptl7 transcripts were successfully amplified and they were differentially expressed during skin regeneration. In the first 2 days of skin regeneration, re-establishment of the physical barrier and an increase in the number of blood vessels was observed. During the initial stages of skin regeneration angptl1b and angptl2b transcripts were significantly more abundant (p < 0.05) than in intact skin and angptl7 transcripts were down-regulated (p < 0.05) throughout the 4-days of skin regeneration that was studied. No difference in angptl4a and angptl4b transcript abundance was detected during regeneration or between regenerating and intact skin. Conclusions The angptl gene family has expanded in teleost genomes. In sea bream, changes in the expression of angptl1b, angptl2b and angptl7 were correlated with the main phases of skin regeneration, indicating the involvement of ANGPTL family members in skin regeneration has been conserved in the vertebrates. Exploration of the fish angptl family in skin sheds new light on the understanding of the molecular basis of skin regeneration an issue of importance for disease control in aquaculture.info:eu-repo/semantics/publishedVersio

    Current EBC development and testing at NASA

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    SiC/SiC Ceramic Matrix Composites (CMCs) are a game changer for advanced power generation equipment because of their high temperature capability, oxidation resistance, and light weight that translate to significant reduction in fuel consumption and emission. Limitations of SiC/SiC CMCs include surface recession and component cracking and associated chemical and physical degradation in the CMC. The solution pursued to mitigate surface recession of SiC/SiC CMCs is the incorporation of coating systems that provide surface protection, which has become known as an Environmental Barrier Coating (EBC). The development of EBCs for the protection of SiC/SiC CMCs was a continuation of coating development work for corrosion protection of silicon-based monolithics. The first and second generation EBCs developed in mid 1990s-early 2000s laid the foundation for current EBCs. Environmental degradation that limits EBC life includes surface recession by steam, oxidation in steam environments, and CMAS-EBC reactions. Many engine tests have been conducted since late 1990s and a first CMC component entered into service in 2016 in a commercial engine. The introduction of CMCs represents significant challenges as failure of the EBC means rapid reduction in component life. A reliable lifing method and engine-relevant testing methods to validate life need to be developed. This paper will current activities on EBC development and testing at NASA

    Temperature responsiveness of gilthead sea bream bone; an in vitro and in vivo approach

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    This study aimed to characterize the molecules involved in osteogenesis in seabream and establish using in vitro/in vivo approaches the responsiveness of selected key genes to temperature. The impact of a temperature drop from 23 to 13 degrees C was evaluated in juvenile fish thermally imprinted during embryogenesis. Both, in vitro/in vivo, Fib1a, appeared important in the first stages of bone formation, and Col1A1, ON and OP, in regulating matrix production and mineralization. OCN mRNA levels were up-regulated in the final larval stages when mineralization was more intense. Moreover, temperature-dependent differential gene expression was observed, with lower transcript levels in the larvae at 18 degrees C relative to those at 22 degrees C, suggesting bone formation was enhanced in the latter group. Results revealed that thermal imprinting affected the long-term regulation of osteogenesis. Specifically, juveniles under the low and low-to-high-temperature regimes had reduced levels of OCN when challenged, indicative of impaired bone development. In contrast, gene expression in fish from the high and high-to-low-temperature treatments was unchanged, suggesting imprinting may have a protective effect. Overall, the present study revealed that thermal imprinting modulates bone development in seabream larvae, and demonstrated the utility of the in vitro MSC culture as a reliable tool to investigate fish osteogenesis."Ministerio de Economia y Competitividad" (MINECO) [BES-2015-074654]; Portuguese Science Foundation (FCT) [SFRH/BPD/111512/2015, SFRH/BD/81625/2011]; MINECO, Spain [AGL2010-17324, AGL2014-57974-R]; "Generalitat de Catalunya" (XRAq); Generalitat de Catalunya [2014SGR-01371]; FCT, Portugal [CCMAR/Multi/04326/2013]; European Union [LIFECYCLE EU-FP7 222719]info:eu-repo/semantics/publishedVersio

    Contributorship and partial inclusion: A communicative perspective

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    Organizational communication tends to assume that the practices of organizational “members” are relevant to the study of organizational phenomena, without reflecting on how those members were identified in the first place. This issue is particularly relevant to perspectives that view communication as constitutive of organizations, since they may take the very object they seek to explain – the organization – as the starting point when identifying pertinent informants. We provide a communicational perspective of organizational membership by starting from “communicative events” (Schoeneborn & Scherer, 2012), instead of individuals. Ethnomethodology’s notions of accounts and sanctions are useful in recognizing the interactionally-performed nature of membership. We extend ethnomethodology’s intuition by viewing membership – which we reframe as contributorship – as being achieved through the contribution of actions to the organization

    Two Decades Of Pelagic Ecology Of The Western Antarctic Peninsula

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    Significant strides in our understanding of the marine pelagic ecosystem of the Western Antarctic Peninsula (WAP) region have been made over the past two decades, resulting from research conducted aboard ARSV Laurence M. Gould and RVIB Nathaniel B. Palmer. These advances range from an understanding of the physical forcing on biology, to food web ecology (from microbes to top predators), to biogeochemical cycling, often in the larger context of rapid climate warming in the region. The proximity of the WAP to the Antarctic Circumpolar Current and WAP continental shelf bathymetry affects the hydrography and helps structure the biological community. Seasonal, spatial, and interannual variability at all levels of the food web, as well as the mechanisms supporting their production, are now more clearly understood. New tools and technologies employed in the region were critical for making this research possible. As a result, our knowledge of the WAP pelagic ecosystem during a time of rapid climate change has vastly improved

    Understanding pseudo-albinism in sole (Solea senegalensis): a transcriptomics and metagenomics approach

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    Pseudo-albinism is a pigmentation disorder observed in flatfish aquaculture with a complex, multi-factor aetiology. We tested the hypothesis that pigmentation abnormalities are an overt signal of more generalised modifications in tissue structure and function, using as a model the Senegalese sole and two important innate immune barriers, the skin and intestine, and their microbiomes. Stereological analyses in pseudo-albino sole revealed a significantly increased mucous cell number in skin (P < 0.001) and a significantly thicker muscle layer and lamina propria in gut (P < 0.001). RNA-seq transcriptome analysis of the skin and gut identified 573 differentially expressed transcripts (DETs, FDR < 0.05) between pseudo-albino and pigmented soles (one pool/tissue from 4 individuals/phenotype). DETs were mainly linked to pigment production, skin structure and regeneration and smooth muscle contraction. The microbiome (16 S rRNA analysis) was highly diverse in pigmented and pseudo-albino skin but in gut had low complexity and diverged between the two pigmentation phenotypes. Quantitative PCR revealed significantly lower loads of Mycoplasma (P < 0.05) and Vibrio bacteria (P < 0.01) in pseudo-albino compared to the control. The study revealed that pseudo-albinism in addition to pigmentation changes was associated with generalised changes in the skin and gut structure and a modification in the gut microbiome.Agência financiadora H2020 European Funds MSCA-RISE project 691102 Portuguese national funds from FCT - Foundation for Science and Technology UID/Multi/04326/2019 Portuguese national funds from the operational programme CRESC Algarve 2020 EMBRC. PT ALG-01-0145-FEDER-022121 Portuguese national funds from the operational programme COMPETE 2020 EMBRC. PT ALG-01-0145-FEDER-022121 European Union (EU) 654008 Fundacao para a Ciencia e a Tecnologia (FCT) SFRH/BPD/84033/2012 Portuguese Institute for Employment and Vocational Training 0068/ET/18info:eu-repo/semantics/publishedVersio

    Ocean acidification affects the expression of neuroplasticity and neuromodulation markers in seabream

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    A possible explanation for acidification-induced changes in fish behaviour is that acidification interferes with neurogenesis and modifies the plasticity of neuronal circuitry in the brain. We tested the effects on the olfactory system and brain of gilthead seabream (Sparus aurata) to 4 weeks' exposure to ocean acidification (OA). Olfactory epithelium (OE) morphology changed shortly after OA exposure and persisted over the 4 weeks. Expression of genes related to olfactory transduction, neuronal excitability, synaptic plasticity, GABAergic innervation, and cell proliferation were unchanged in the OE and olfactory bulb (OB) after 4 weeks' exposure. Short-term changes in the ionic content of plasma and extradural fluid (EDF) returned to control levels after 4 weeks' exposure, except for [Cl-], which remained elevated. This suggests that, in general, there is an early physiological response to OA and by 4 weeks a new homeostatic status is achieved. However, expression of genes involved in proliferation, differentiation and survival of undifferentiated neurons were modified in the brain. In the same brain areas, expression of thyroid hormone signalling genes was altered suggesting modifications in the thyroid-system may be linked to the changes in neuroplasticity and neurogenesis. Overall, the results of the current study are consistent with and effect of OA on neuroplasticity.Mexican national funds from CONACYT -Consejo Nacional de Ciencia y Tecnologi'a, Mexico 2018-000022-01info:eu-repo/semantics/publishedVersio

    Covered self-expandable metal stents for pancreatic duct stricture: a systematic review and meta-analysis

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    Background and study aims Placement of a covered (C)-self-expandable metal stent (SEMS) has been recently investigated as an alternative endoscopic treatment for main pancreatic duct stricture (MPDS) in chronic pancreatitis. Our aim was to carry out a systematic review and meta-analysis of studies quantifying efficacy and safety of C-SEMSs in the management of MPDS.Methods A multiple database search was performed, including MEDLINE, Embase and Cochrane Library, from January 2000 to September 2020, to identify studies reporting the efficacy and safety of C-SEMSs in patients with MPDS. Stricture and pain resolution were investigated. Other outcomes included technical success, stent migration, stricture recurrence and need for repeated stent placement. Pancreatitis, severe abdominal pain requiring stent removal and de-novo stricture were recorded as complications.Results Nineteen studies were identified, which included a total of 300 patients. C-SEMSs showed a pooled stricture resolution rate of 91 % [95 % confidence interval (CI), 85 %-96 %] and a pooled pain resolution rate of 92 % (95 % CI, 85 %-98 %). The pooled proportion for stricture recurrence was equal to 6 % (95 % CI, 1 %-14 %), while stent migration occurred in 33 of 300 patients, the pooled proportion being 7 % (95 % CI 1 %-15 %). The pooled mean stent duration was 133 days (95 % CI, 100-166 days). The most common complication was pancreatitis (3 %, 95 % CI 0 %-8 %), while de-novo stricture pooled proportion was 2 % (95 % CI, 0 %-5 %).Conclusions C-SEMSs are effective and safe in the treatment of MPDS. However, there is a significant need for further high-quality, well-designed studies to produce evidence-based data on short and long-term efficacy, safety, costs of C-SEMSs, and also optimal stent duration
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