RCAAP Repository

Trypanosoma brucei is responsible for lethal diseases in humans and cattle in Sub-Saharan Africa. These extracellular parasites extravasate from the blood circulation into several tissues. The importance of the vasculature in tissue tropism is poorly understood. Using intravital imaging and bioluminescence, we observe that gonadal white adipose tissue and pancreas are the two main parasite reservoirs. We show that reservoir establishment happens before vascular permeability is compromised, suggesting that extravasation is an active mechanism. Blocking endothelial surface adhesion molecules (E-selectin, P-selectins, or ICAM2) significantly reduces extravascular parasite density in all organs and delays host lethality. Remarkably, blocking CD36 has a specific effect on adipose tissue tropism that is sufficient to delay lethality, suggesting that establishment of the adipose tissue reservoir is necessary for parasite virulence. This work demonstrates the importance of the vasculature in a T. brucei infection and identifies organ-specific adhesion molecules as key players for tissue tropism.

Light is an important regulator of daily human physiology in providing time-of-day information for the circadian clock to stay synchronised with the 24-hr day. The coronavirus disease 2019 (COVID-19) pandemic led to social restrictions in many countries to prevent virus spreading, restrictions that dramatically altered daily routines and limited outdoor daylight exposure. We previously reported that sleep duration increased, social jetlag decreased, and mid-sleep times delayed during social restrictions (Global Chrono Corona Survey, N = 7,517). In the present study, we investigated in the same dataset changes in wellbeing and their link to outdoor daylight exposure, and sleep-wake behaviour. In social restrictions, median values of sleep quality, quality of life, physical activity and productivity deteriorated, while screen time increased, and outdoor daylight exposure was reduced by ~58%. Yet, many survey participants also reported no changes or even improvements. Larger reductions in outdoor daylight exposure were linked to deteriorations in wellbeing and delayed mid-sleep times. Notably, sleep duration was not associated with outdoor daylight exposure loss. Longer sleep and decreased alarm-clock use dose-dependently correlated with changes in sleep quality and quality of life. Regression analysis for each wellbeing aspect showed that a model with six predictors including both levels and their deltas of outdoor daylight exposure, sleep duration and mid-sleep timing explained 5%-10% of the variance in changes of wellbeing scores (except for productivity). As exposure to daylight may extenuate the negative effects of social restriction and prevent sleep disruption, public strategies during pandemics should actively foster spending more daytime outdoors.

O projecto Clear-PEM é um projecto de investigação que está a ser desenvolvido em Portugal com o intuito de construir um scanner de mamografia por emissão de positrão (MEP). A plataforma de software de reconstrução de imagem existente no Clear-PEM utiliza uma organização de dados em linogramas e algoritmos de reconstrução iterativos. Em certas situações em MEP, a região de interesse (ROI) de uma imagem pode estar limitada a uma área específica, sendo importante a visualização desta ROI com uma resolução espacial melhor. Nestes casos é desejável reconstruir apenas a ROI, sem desperdiçar esforços nos pixéis restantes. No entanto, para funcionar correctamente, os algoritmos iterativos requerem que a ROI inclua o objecto emissor na sua totalidade. Uma solução possível, seria reconstruir a imagem inteira com um tamanho de pixel igual ao desejado na ROI e seleccionar apenas os pixéis relevantes. Este procedimento seria no entanto demasiado lento e ineficiente. Este trabalho consistiu em testar a viabilidade da integração na plataforma de software existente no projecto, de um método (baseado na técnica descrita por Stearns [1]) para reconstruir eficientemente apenas uma ROI de interesse com uma resolução superior à originalmente utilizada para a totalidade da imagem. Esta reconstrução, a que chamamos Reconstrução Dirigida, realiza-se após ser estimada a contribuição para a actividade fora da ROI a partir de uma primeira reconstrução da imagem feita com uma resolução inferior.

This paper explains how a participative approach was used to collect first-hand citizens’ suggestions on how to improve science communication regarding Climate Change. A public consultation involving citizens from 5 different European countries revealed various perspectives concerning their communication preferences on scientific topics. Five main themes emerged following citizens' proposals for better communication and involvement: producer of information, medium, message strategies, audiences and areas of action and engagement.

Colorectal cancer (CRC) is one of the most common cancers worldwide. Although short-term cultures of tumour sections and xenotransplants have been used to determine drug efficacy, the results frequently fail to confer clinically useful information. Biomarker discovery has changed the paradigm for advanced CRC, though the presence of a biomarker does not necessarily translate into therapeutic success. To improve clinical outcomes, translational models predictive of drug response are needed. We describe a simple method for the fast establishment of CRC patient-derived explant (CRC-PDE) cultures from different carcinogenesis pathways, employing agitation-based platforms. A total of 26 CRC-PDE were established and a subset was evaluated for viability (n = 23), morphology and genetic key alterations (n = 21). CRC-PDE retained partial tumor glandular architecture and microenvironment features were partially lost over 4 weeks of culture. Key proteins (p53 and Mismatch repair) and oncogenic driver mutations of the original tumours were sustained throughout the culture. Drug challenge (n = 5) revealed differential drug response from distinct CRC-PDE cases. These findings suggest an adequate representation of the original tumour and highlight the importance of detailed model characterisation. The preservation of key aspects of the CRC microenvironment and genetics supports CRC-PDE potential applicability in pre- and co-clinical settings, as long as temporal dynamics are considered.

Este relatório centra-se nos principais resultados do inquérito online “Os impactos sociais da pandemia - o segundo confinamento”, coordenado por uma equipa de investigadoras do Instituto de Ciências Sociais da Universidade de Lisboa (ICS-ULisboa), que decorreu entre os dias 11 a 25 de Fevereiro de 2021, ou seja, durante o 11º estado de emergência nacional. À data da recolha dos dados, o cenário epidemiológico em Portugal era grave, com um número médio de novas infeções diárias a rondar os 1800 casos e contabilizando um número de 100 óbitos diários. A amostra obtida é uma amostra “bola de neve” ou “guiada pelo respondente”, tendo sido recolhidas 7873 respostas de inquiridos a residir em Portugal, com 16 ou mais anos de idade. Ao longo deste relatório focamo-nos na análise diferenciada dos impactos da pandemia nas diversas esferas da vida, nos diferentes grupos sociais e nas experiências vividas dos indivíduos e das famílias em cenário de confinamento. Para tal, centramo-nos em cinco questões: • Em que medida o confinamento de 2021 foi mais fácil, igual ou mais difícil do que o confinamento de 2020? • Quais os impactos da pandemia na vida profissional dos indivíduos? • Como é que os jovens viveram os seus quotidianos estudantis durante o confinamento e quais as suas maiores preocupações face ao futuro? • Como é que foi vivida a doença por aqueles que estiveram infetados com COVID-19 e que sequelas deixou tal experiência? • Quais os níveis de confiança nas instituições e decisores políticos e a quem é atribuída uma maior responsabilidade pela situação epidemiológica do país?

In gastric cancer (GC), biomarkers that define prognosis and predict treatment response remain scarce. We hypothesized that the extent of CD44v6 membranous tumor expression could predict prognosis and therapy response in GC patients. Two GC surgical cohorts, from Portugal and South Korea (n = 964), were characterized for the extension of CD44v6 membranous immuno-expression, clinicopathological features, patient survival, and therapy response. The value of CD44v6 expression in predicting response to treatment and its impact on prognosis was determined. High CD44v6 expression was associated with invasive features (perineural invasion and depth of invasion) in both cohorts and with worse survival in the Portuguese GC cohort (HR 1.461; 95% confidence interval 1.002-2.131). Patients with high CD44v6 tumor expression benefited from conventional chemotherapy in addition to surgery (p < 0.05), particularly those with heterogeneous CD44v6-positive and -negative populations (CD44v6_3+) (p < 0.007 and p < 0.009). Our study is the first to identify CD44v6 high membranous expression as a potential predictive marker of response to conventional treatment, but it does not clarify CD44v6 prognostic value in GC. Importantly, our data support selection of GC patients with high CD44v6-expressing tumors for conventional chemotherapy in addition to surgery. These findings will allow better stratification of GC patients for treatment, potentially improving their overall survival.

Attachment security has been associated with health status and symptom reporting. In this longitudinal study, we investigated the association between antibiotics uptake by infants at 9-months and mother-infant attachment at 12-months. Logistic regression analyses indicated that lower maternal sensitivity was associated with increased odds of antibiotic uptake. Furthermore, 89.7% of insecure-ambivalent infants consumed antibiotics, which contrasted with 32.5% of avoidant infants and 21.5% of secure infants. This study suggests that maternal behavior and mother-infant attachment impact on antibiotic consumption, which is worrying because antibiotics may lead to several health problems later in life and antibiotic-resistance.

Adipose tissue is one of the major reservoirs of Trypanosoma brucei parasites, the causative agent of sleeping sickness, a fatal disease in humans. In mice, the gonadal adipose tissue (AT) typically harbors 2-5 million parasites, while most solid organs show 10 to 100-fold fewer parasites. In this study, we tested whether the AT environment responds immunologically to the presence of the parasite. Transcriptome analysis of T. brucei infected adipose tissue revealed that most upregulated host genes are involved in inflammation and immune cell functions. Histochemistry and flow cytometry confirmed an increasingly higher number of infiltrated macrophages, neutrophils and CD4+ and CD8+ T lymphocytes upon infection. A large proportion of these lymphocytes effectively produce the type 1 effector cytokines, IFN-γ and TNF-α. Additionally, the adipose tissue showed accumulation of antigen-specific IgM and IgG antibodies as infection progressed. Mice lacking T and/or B cells (Rag2-/-, Jht-/-), or the signature cytokine (Ifng-/-) displayed a higher parasite load both in circulation and in the AT, demonstrating the key role of the adaptive immune system in both compartments. Interestingly, infections of C3-/- mice showed that while complement system is dispensable to control parasite load in the blood, it is necessary in the AT and other solid tissues. We conclude that T. brucei infection triggers a broad and robust immune response in the AT, which requires the complement system to locally reduce parasite burden.

In mammals, the zona pellucida glycoprotein 3 (ZP3) is considered a primary sperm receptor of the oocyte and is hypothesized to be involved in reproductive isolation. We investigated patterns of diversity and selection in the putative sperm-binding region (pSBR) of mouse ZP3 across Cricetidae and Murinae, two hyperdiverse taxonomic groups within muroid rodents. In murines, the pSBR is fairly conserved, in particular the serine-rich stretch containing the glycosylation sites proposed as essential for sperm binding. In contrast, cricetid amino acid sequences of the pSBR were much more variable and the serine-rich motif, typical of murines, was generally substantially modified. Overall, our results suggest a general lack of species specificity of the pSBR across the two muroid families. We document statistical evidence of positive selection acting on exons 6 and 7 of ZP3 and identified several amino acid sites that are likely targets of selection, with most positively selected sites falling within or adjacent to the pSBR.

Despite the progress in sustainable development strategies, the role of the Amazon rainforest as a carbon sink faces increasing disturbances that may have a critical impact on global climate. Understanding the vulnerability of the Amazon rainforest to climate change is a major challenge, considering the complex interaction between human and natural systems. This paper aims, via an interdisciplinary approach, to assess the observed evolution and possible future of the Amazon rainforest, considering different global climate and socio-economic scenarios. By comparing historical with plausible future developments, we present key knowledge to inform mitigation and regional adaptation policy considerations. As an entry point, historical trends of annual mean temperature and precipitation were analysed. In a second step, the same assessment was made for the mean annual NDVI sum (a proxy of yearly plant productivity), representing vegetation strength. For these purposes, a 34-year period (1982–2015) was considered. Trends were analysed based on non-parametric Mann-Kendall and Sen's methods. With this representation of the past, the next step focused on future scenarios. The most plausible global emission pathways were evaluated via the comparison of ten assessments of the possible effects of the mitigation action plans of national governments, as stated in the National Determined Contributions (NDCs). Results indicate a strong consensus that if either current policies, unconditional or conditional NDCs are fulfilled, the limit of global warming by “well below 2 °C” will be exceeded. In this context, climate projections for the Amazon suggest, among other results, an increase in the range of 1.3 °C (lower limit under SSP1-2.6) to 6.5 °C (upper limit under SSP5-8.5). Unlike temperature, positive and negative anomalies are expected for precipitation depending on location. Despite the uncertainty regarding the projections, possible changes such as forest diebacks and savannization may take place, namely in southeastern Amazon, by the end of the century. Overall, this study highlights the importance of carefully considering the combination of different factors, such as deforestation, to guarantee rainforest resilience under climate-driven changes.

In seasonal environments, sinks that are more persistent than sources may serve as temporal stepping stones for specialists. However, this possibility has to our knowledge, not been demonstrated to date, as such environments are thought to select for generalists, and the role of sinks, both in the field and in the laboratory, is difficult to document. Here, we used laboratory experiments to show that herbivorous arthropods associated with seasonally absent main (source) habitats can endure on a suboptimal (sink) host for several generations, albeit with a negative growth rate. Additionally, they dispersed towards this host less often than towards the main host and accepted it less often than the main host. Finally, repeated experimental evolution attempts revealed no adaptation to the suboptimal host. Nevertheless, field observations showed that arthropods are found in suboptimal habitats when the main habitat is unavailable. Together, these results show that evolutionary rescue in the suboptimal habitat is not possible. Instead, the sink habitat functions as a temporal stepping stone, allowing for the persistence of a specialist when the source habitat is gone.

Historical factors (colonization scenarios, demographic oscillations) and contemporary processes (population connectivity, current population size) largely contribute to shaping species’ present-day genetic diversity and structure. In this study, we use a combination of mitochondrial and nuclear DNA markers to understand the role of Quaternary climatic oscillations and present-day gene flow dynamics in determining the genetic diversity and structure of the newt Calotriton asper (Al. Dugès, 1852), endemic to the Pyrenees. Mitochondrial DNA did not show a clear phylogeographic pattern and presented low levels of variation. In contrast, microsatellites revealed five major genetic lineages with admixture patterns at their boundaries. Approximate Bayesian computation analyses and linear models indicated that the five lineages likely underwent separate evolutionary histories and can be tracked back to distinct glacial refugia. Lineage differentiation started around the Last Glacial Maximum at three focal areas (western, central and eastern Pyrenees) and extended through the end of the Last Glacial Period in the central Pyrenees, where it led to the formation of two more lineages. Our data revealed no evidence of recent dispersal between lineages, whereas borders likely represent zones of secondary contact following expansion from multiple refugia. Finally, we did not find genetic evidence of sex-biased dispersal. This work highlights the importance of integrating past evolutionary processes and present-day gene flow and dispersal dynamics, together with multilocus approaches, to gain insights into what shaped the current genetic attributes of amphibians living in montane habitats.

O papel da insulina e do seu receptor (InsR) no cérebro é ainda obscuro conhecendo-se contudo funções importantes na aprendizagem e na memória; aponta-se também para uma associação entre doença de Alzheimer (DA) e a Diabetes. Sabe-se igualmente que a insulina controla a neuroexcitabilidade em neurónios específicos. No nosso laboratório demonstrou-se que a insulina inibe a componente lenta- Islow das correntes de K+ activadas-por-voltagem em neurónios piramidais da zona CA1 do hipocampo de ratos. Tal efeito é observado unicamente em neurónios provenientes de animais em período pós-prandial (e não em jejum). Este trabalho propõe (a) identificar o canal de K+ sensível à insulina nestes neurónios; (b) investigar os fenómenos fisiológicos subjacentes à referida diferença observada entre" preparações em jejum" e "em pós-prandial". Recorreu-se à técnica whole-cell voltage-clamp e a técnicas de western-blotting e imunocitoquímica com anticorpos contra InsR e o canal de K+ candidato. Registos de corrente revelaram que a Margatoxina (bloqueador especifico de canais K+ tipo-KV1.3) inibe também especificamente Islow (EC50=125 pM), alterando a dependência da activação à voltagem. Experiências com tratamentos articulados de insulina e várias concentrações de margatoxina indicam o canal Kv1.3 como o responsável pelo efeito da insulina nos neurónios CA1. Demonstrou-se, por electrofisiologia e por western-blot, que a expressão do InsR é maior no período de pós-prandial. Mostra-se ainda que o canal Kv1.3 é mais expresso em ―hipocampos em pós-prandial‖ e assim postula-se uma oscilação na expressão do InsR e do canal Kv1.3 durante o ciclo jejum/pós-prandial. Finalmente, usando amostras de cérebro de ratos-modelo obesos (OZR) e diabéticos (ZDF), verificou-se que a expressão do InsR nestes dois é inferior à do controlo, o que atribui protagonismo ao cérebro no contexto das diabetes. Assim, a insulina- neural controla a neuroactividade num processo dependente do ciclo alimentar. Questiona-se consequentemente a ideia do cérebro como uma entidade isolada dos ciclos metabólicos.

Within the Tejo Estuary, non-indigenous species (NIS) Spartina patens colonizes the upper middle marsh competing with the native Halimione portulacoides for space and resources. Due to the very different root system and metabolism between both species, this invasion can have significant biogeochemical implications, namely in terms of metal speciation and availability. In the present study, we evaluate the biogeochemical modifications in terms of metal speciation introduced by the colonization of the NIS S. patens. Total metals Cu, Zn, Pb and As within the rhizosediment varied between the two study species but was generally higher in the rhizosediment of H. portulacoides. These differences could be attributed to the higher organic content and smaller sand fraction found in the rhizosediment of H. portulacoides. Zinc was found to have highest concentration (H. portulacoides 126.22 mg g−1, S. patens 68.35 mg g−1) in the rhizosediments while Cu and As were least concentrated metals. Considering the bioavailable fractions (F1 + F2) Cu, Zn and As were more readily available in the sediment beneath NIS S. patens than in H. portulacoides and Pb presented no significance (p = 0.835). Overall, H. portulacoides rhizosediments had higher total metal concentration, whilst the rhizosediments of NIS S. patens presented a higher percentage of bioavailable metals. Thus, the bioinvasion and expansion of NIS S. patens may have implications for metal biogeochemistry and the natural remediation capacity of salt marshes in estuaries along the Mediterranean and North-eastern Atlantic coasts, as well as ensuing biodiversity and potential trophic web contamination consequences.

“Conservation-reliant species” – those fully dependent on continued management actions – are booming and, with limited conservation budgets, securing funds to sustain their long-term viability is becoming overwhelming. This study assesses the degree of dependence on conservation actions of two obligatory cavity-nesters, the Lesser Kestrel Falco naumanni and the European Roller Coracias garrulus, whose populations in Europe were recently recovered through artificial nest-site provisioning. Using long-term monitoring data and population surveys conducted in their main Portuguese stronghold, we examined temporal changes in the availability and use of semi-natural (cavities in rural abandoned buildings) and artificial nest-sites. We further assessed the financial costs of nest-site provisioning and evaluated the potential use of tourism revenues as a conservation funding source. Following the implementation of conservation projects, the Lesser Kestrel and Roller populations have been increasing but >65% of all breeding pairs currently nest in artificial nest-sites. Semi-natural nest-sites remain suitable for approximately 30 years and are expected to disappear by the end of this century. Lesser Kestrels and Rollers will thus become fully dependent on artificial nest-sites and sustaining their current population sizes is estimated to cost 4500€ per year. This represents <1% of the region's lodging income, largely supported by nature-based tourism. Our findings suggest that reactive conservation measures can be very effective at recovering endangered populations but can make them fully reliant on the perpetuation of those measures. This demands long-term funding, which can be alleviated by tourism revenues in areas with high nature capital values.

Conceptual models underpin river ecosystem research. However, current models focus on continuously flowing rivers and few explicitly address characteristics such as flow cessation and drying. The applicability of existing conceptual models to nonperennial rivers that cease to flow (intermittent rivers and ephemeral streams, IRES) has not been evaluated. We reviewed 18 models, finding that they collectively describe main drivers of biogeochemical and ecological patterns and processes longitudinally (upstream-downstream), laterally (channel-riparian-floodplain), vertically (surface water-groundwater), and temporally across local and landscape scales. However, perennial rivers are longitudinally continuous while IRES are longitudinally discontinuous. Whereas perennial rivers have bidirectional lateral connections between aquatic and terrestrial ecosystems, in IRES, this connection is unidirectional for much of the time, from terrestrial-to-aquatic only. Vertical connectivity between surface and subsurface water occurs bidirectionally and is temporally consistent in perennial rivers. However, in IRES, this exchange is temporally variable, and can become unidirectional during drying or rewetting phases. Finally, drying adds another dimension of flow variation to be considered across temporal and spatial scales in IRES, much as flooding is considered as a temporally and spatially dynamic process in perennial rivers. Here, we focus on ways in which existing models could be modified to accommodate drying as a fundamental process that can alter these patterns and processes across spatial and temporal dimensions in streams. This perspective is needed to support river science and management in our era of rapid global change, including increasing duration, frequency, and occurrence of drying.

Special issue Mapping and Modelling Soil Erosion to Address Societal Challenges in a Changing World presents advances in interdisciplinary methodologies for the study of the soil erosion/land management/climate change nexus, with a focus on societal challenges linked to land degradation. Contribution of 22 research teams active in 17 countries all over the world provided a global perspective on how soil erosion research contributes to meet societal challenges of our time. The authors conclude that (a) inclusive representation of non-linear system feedback between erosion and land management; (b) combination of mapping, measuring, monitoring, and modelling methods on different temporal and spatial scales; and (c) inclusive, cooperative interdisciplinary research approaches are inevitable to support management aiming for land degradation neutrality.

Collision with power lines is a major cause of mortality for many bird species. Understanding the biotic and abiotic factors that increase collision risk is therefore important for implementing mitigation measures to minimize mortality, such as power line rerouting or wire marking. Here, we used collision events registered during 2003–2015 along 280 km of transmission power lines in southern Portugal to analyse spatio-temporal patterns and collision risk factors in two sympatric, threatened, and collision-prone species: the great bustard Otis tarda and the little bustard Tetrax tetrax. The occurrence of collisions was not uniform across space and time, and variations could be explained by the species' ecological requirements, distribution patterns and behaviour. Although both species fly considerable distances between areas of suitable habitat, collisions were far more likely in power line sections with > 20% (for the little bustard) or > 50% (for the great bustard) of open farmland habitat in the surroundings. Power line configuration was also important: taller pylons and those with a higher number of wire levels posed a higher risk for both species. Wire marking had a small but significant effect for the little bustard, reducing collisions risk. There was, however, no similar effect for the great bustard, possibly a result of limited data. Mitigation measures should be implemented to prevent bustard collisions, including adequate route planning, ideally avoiding areas with > 20% of open habitat. Line configuration and wire marking are particularly important where such localities cannot be avoided and power lines cross areas with a high proportion of bustard habitat, including outside protected areas.

Five decades ago, a landmark paper in Science titled The Cave Environment heralded caves as ideal natural experimental laboratories in which to develop and address general questions in geology, ecology, biogeography, and evolutionary biology. Although the ‘caves as laboratory’ paradigm has since been advocated by subterranean biologists, there are few examples of studies that successfully translated their results into general principles. The contemporary era of big data, modelling tools, and revolutionary advances in genetics and (meta)genomics provides an opportunity to revisit unresolved questions and challenges, as well as examine promising new avenues of research in subterranean biology. Accordingly, we have developed a roadmap to guide future research endeavours in subterranean biology by adapting a well-established methodology of ‘horizon scanning’ to identify the highest priority research questions across six subject areas. Based on the expert opinion of 30 scientists from around the globe with complementary expertise and of different academic ages, we assembled an initial list of 258 fundamental questions concentrating on macroecology and microbial ecology, adaptation, evolution, and conservation. Subsequently, through online surveys, 130 subterranean biologists with various backgrounds assisted us in reducing our list to 50 top-priority questions. These research questions are broad in scope and ready to be addressed in the next decade. We believe this exercise will stimulate research towards a deeper understanding of subterranean biology and foster hypothesis-driven studies likely to resonate broadly from the traditional boundaries of this field.