1,359 research outputs found
Evolution of the angiopoietin-like gene family in teleosts and their role in skin regeneration
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
Thermal imprinting modifies adult stress and innate immune responsiveness in the teleost sea bream
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
Media and digital skills of visual impaired students
The developed world is being
proactive in transitioning to a digital society.
Thus, understanding and gathering information
about the Media and Digital Skills (MDS) of
visual impaired (VI) students is an important
issue for evaluating this group's present and
future integration into society.
With the purpose of accessing VI students'
MDS, a questionnaire was administered to two
samples of students, one from Portugal and the
other from Greece. A multiple linear regression
model was used to modulate the effect on MDS
of age, sex, country, and type of vision
impairment.
The model justifies a considerable amount of
MDS variance, with age and vision being
statistically significant factors. In the model,
MDS improves with age increment, and blinds
have lower MDS scores than their normal sight
counterparts.
Considering that blindness impairs the MDS of
this subject group, particular efforts should be
made by schools and society to potentiate the
improvement of MDS in this specific group
Ocean acidification affects the expression of neuroplasticity and neuromodulation markers in seabream
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
Understanding pseudo-albinism in sole (Solea senegalensis): a transcriptomics and metagenomics approach
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
Feature selection optimization of risk factors for coronary heart disease
Cardiovascular disease is a worldwide problem and is the main cause of mortality when coronary heart disease leads to a heart attack. Hence, it is important to evaluate how to prevent this disease considering the symptoms description and physical examinations.This study points out the application and comparison of different performance measures for the classification of heart disease. Firstly, a feedforward neural network was applied to classify heart disease risk, using the well-known Framingham database. Feature selection optimization was performed to identify the most important variables to take into consideration, minimizing the Type II error and maximizing the accuracy. In addition, a multi-objective optimization algorithm was carried out to simultaneously optimize both performance measures. A set of non-dominated solutions representing the trade-offs between objectives were obtained, and gender, age, systolic blood pressure, and glucose level emerged as the principal factors to take into consideration to predict heart disease. The results obtained are promising and show the importance of considering more than one criterion to identify the most important variables.This work has been supported by FCT -Fundacao para a Ciencia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020
Discussing impact assessment on creative tourism: A theoretical and analytical model
Over the last decades, tourism has experienced exponential growth, expansion and diversification, being considered one of the most important socio-economic sectors, an essential source of income and employment for many territories (e.g. Bellini et al. 2017; Romão and Nijkamp 2017; Weidenfeld 2018). In response to the concerns about the negative impacts of tourism and to improve the relationship between hosts and tourists, culture-based creativity is seen as a path to create competitive advantages and improve more sustainable practices in the tourism field.
Therefore, many cities and regions have sought to reinvent themselves as creative tourist destinations, by encouraging synergies between tourism and the cultural and creative activities to foster the development of new products, experiences and markets (Delisle and Jolin 2007; Duxbury and Richards 2019; Richards and Wilson 2007).
Despite the high attractiveness of large capitals and metropolises, small towns and rural areas can also benefit from the growth of tourist flows and the demand for less overcrowded tourist destinations. Alternatively, they can offer interactive, small-scale, unique and tailor-made experiences based on local culture, lifestyles, and values thus generating potential positive impacts on these communities (Richards and Duif 2018; Wisansing and Vongvisitsin 2019).
In the discussion of tourism development models, sustainability has become an unavoidable frame of reference, introducing cultural, social and environmental concerns, in addition to the analysis of economic issues. In this vein, we consider the integration of culture as a fundamental dimension of the analysis, together and in interrelation with the economic, social and environmental dimensions. Although the impact assessment exercises have focused on predominantly economic indicators, there is an increasing number of methods that can determine and monitor more accurately the multiple links and impacts of tourist activities in local communities, and also address sustainability issues.
This paper has the objective of review the main theoretical and methodological approaches about impact assessment, to develop a comprehensive and operational framework capable of contributing to a better understanding the multifaced nature of creative tourism and their diverse impacts to support the formulation of policies for the sector and according to each context.FCT; FEDE
Strategies for adaptation of mAb-producing CHO cells to serum-free medium
Large-scale production of biopharmaceuticals commonly requires the use of serum-free medium, for safety and cost reasons. However, serum is essential to most mammalian cells growth, and its removal implies a very time-consuming process for cell adaptation. Thus, the aim of the study was to evaluate different strategies for cell adaptation to serum-free medium.
Three cell types were used to assess the impact of transfection on adaptation: one common CHO-K1 cell line and two CHO-K1 cells transfected with different technologies for antibody production. Cultures were started with a known cell concentration in Dulbecco’s Modified Eagle Medium supplemented with 10% serum. The effect of five combinations of supplements, that could support cells during adaptation, was tested. These supplements included insulin and trace elements (copper sulfate, zinc sulfate, sodium selenite, ammonium iron citrate, ferrous ammonium sulfate, ammonium metavanadate, nickel chloride and stannous chloride). A methodology of gradual adaptation was followed, consisting on sequential steps of serum reduction, after assuring good cell adaptation from the previous step. After reaching 0.625% serum, medium was gradually switched to the chemically defined serum-free EX-CELL CHO DHFR- medium.
It was observed that supplements influence cell adaptation to serum-free medium. Indeed, the combinations containing the trace element ammonium iron citrate gave the worst results, with cell death at 2.5% serum. In contrast, the combination of ammonium metavanadate, nickel chloride and stannous chloride proved to be the most favorable to the three cell lines. Comparing the cells, it seems that the ability to produce antibody and the transfection methodology used does not have a great impact on adaptation.
During the study, some procedure details were identified as particularly important and should be carefully considered in the process of cell adaptation to serum-free medium. These include the use of a higher initial cell concentration that will allow the survival of an increased number of cells during the process; avoiding harsh procedures to the cells such as centrifugation and the use of enzymes (i.e. trypsin), due to a higher cell sensibility during adaptation; and to give enough time for a full cell adaptation at each step
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