31 research outputs found

    The use of muscle biomarkers for assessing physiological effects of heavy metal pollution in the greater white-toothed shrew (Crocidura russula)

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    The greater white-toothed shrew Crocidura russula has been used as a sentinel species for estimating environmental risks to human populations. Previous studies in mining areas have focused on the liver of shrews as the primary target of physiological and metabolic changes due to heavy metal pollution. However, populations persist even when detoxification by the liver seems to be compromised and damage is observed. These pollutant-adapted individuals inhabiting contaminated sites may exhibit altered biochemical parameters that confer increased tolerance in various tissues other than the liver. The skeletal muscle tissue of C. russula might be an alternative tissue that allows the survival of organisms inhabiting historically polluted sites due to the detoxification of redistributed metals. Organisms from two heavy metal mine populations and one population derived from an unpolluted site were used to determine the detoxification activities, antioxidant capacity, and oxidative damage, as well as cellular energy allocation parameters and acetylcholinesterase activity (a biomarker of neurotoxicity). Muscle biomarkers differ between shrews from polluted sites and shrews from the unpolluted location, with the mine animals showing: (1) a decreased energy consumption concomitant with increased energy reserves and total available energy; (2) reduced cholinergic activity, suggesting an impairment of neurotransmission at the neuromuscular junction; (3) an overall decrease in detoxification capacity and enzymatic antioxidant response and a higher level of lipid damage. Also, some of these markers differed between females and males. These changes may have resulted from a decreased detoxifying capacity of the liver and could potentially bring about significant ecological effects for this highly active species. Heavy metal pollution induced physiological changes in Crocidura russula showing that skeletal muscle may serve as a backup sink organ allowing rapid species adaptation and evolution.publishe

    Distribution of alien tetrapods in the Iberian Peninsula

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    We present a dataset that assembles occurrence records of alien tetrapods (amphibians, reptiles, birds and mammals) in the Iberian Peninsula, a coherent biogeographically unit where introductions of alien species have occurred for millennia. These data have important potential applications for ecological research and management, including the assessment of invasion risks, formulation of preventive and management plans, and research at the biological community level on alien species. This dataset summarizes inventories and data sources on the taxonomy and distribution of alien tetrapods in the Iberia Peninsula, comprising known locations from published literature, expert knowledge and citizen science platforms. An expert-based assessment process allowed the identification of unreliable records (misclassification or natural dispersion from native range), and the classification of species according to their status of reproduction in the wild. Distributional data was harmonized into a common area unit, the 10 × 10 km Universal Transverse Mercator (UTM) system (n = 6,152 cells). The year of observation and/or year of publication were also assigned to the records. In total, we assembled 35,940 unique distribution records (UTM × species × Year) for 253 species (6 amphibians, 16 reptiles, 218 birds and 13 mammals), spanning between 1912 and 2020. The species with highest number of distribution records were the Mediterranean painted frog Discoglossus pictus (n = 59 UTM), the pond slider Trachemys scripta (n = 471), the common waxbill Estrilda astrild (n = 1,275) and the house mouse Mus musculus (n = 4,043), for amphibians, reptiles, birds and mammals, respectively. Most alien species recorded are native to Africa (33%), followed by South America (21%), Asia (19%), North America (12%) and Oceania (10%). Thirty-six species are classified by IUCN as threatened in their native range, namely 2 Critically Endangered (CR), 6 Endangered (EN), 8 Vulnerable (VU), and 20 species Near Threatened (NT). Species maps are provided in DataSet1, as well R code and GIS layers to update them as new records are obtained.info:eu-repo/semantics/publishedVersio

    Revisión a nivel ibérico de la distribución del topillo de Cabrera o iberón, Iberomys cabrerae (Thomas, 1906)

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    Neste estudo é apresentado um mapa de quadrículas UTM 10x10 km para toda a área de distribuição de Iberomys cabrerae. A partir dos dados obtidos destacamos que a) as 420 quadrículas com dados se concentram em 4 grandes núcleos disjuntos (Luso-Carpetano, Montibérico, Bético y Prepirenaico), das quais o mais importante é o Luso-Carpetano e o mais pequeno, isolado e ameaçado é o Preirenáico; b) é necessário intensificar a procura de populações em áreas ainda pouco estudadas; e c) os dados disponíveis sobre a situação das populações têm uma qualidade muito desigual, diferindo igualmente entre regiões, o que não permite ter uma imagem clara do seu estado de conservação, nem desenvolver estratégias de proteção e gestão adequadas

    Value of adenosine infusion for infarct size determination using real-time myocardial contrast echocardiography

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    BACKGROUND: Myocardial contrast echocardiography has been used for determination of infarct size (IS) in experimental models. However, with intermittent harmonic imaging, IS seems to be underestimated immediately after reperfusion due to areas with preserved, yet dysfunctional, microvasculature. The use of exogenous vasodilators showed to be useful to unmask these infarcted areas with depressed coronary flow reserve. This study was undertaken to assess the value of adenosine for IS determination in an open-chest canine model of coronary occlusion and reperfusion, using real-time myocardial contrast echocardiography (RTMCE). METHODS: Nine dogs underwent 180 minutes of coronary occlusion followed by reperfusion. PESDA (Perfluorocarbon-Exposed Sonicated Dextrose Albumin) was used as contrast agent. IS was determined by RTMCE before and during adenosine infusion at a rate of 140 mcg·Kg(-1)·min(-1). Post-mortem necrotic area was determined by triphenyl-tetrazolium chloride (TTC) staining. RESULTS: IS determined by RTMCE was 1.98 ± 1.30 cm(2 )and increased to 2.58 ± 1.53 cm(2 )during adenosine infusion (p = 0.004), with good correlation between measurements (r = 0.91; p < 0.01). The necrotic area determined by TTC was 2.29 ± 1.36 cm(2 )and showed no significant difference with IS determined by RTMCE before or during hyperemia. A slight better correlation between RTMCE and TTC measurements was observed during adenosine (r = 0.99; p < 0.001) then before it (r = 0.92; p = 0.0013). CONCLUSION: RTMCE can accurately determine IS in immediate period after acute myocardial infarction. Adenosine infusion results in a slight better detection of actual size of myocardial damage

    The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

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    INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    The influence of local, landscape and spatial factors on the distribution of the Lusitanian and the Mediterranean pine voles in a Mediterranean landscape

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    This study evaluated the relative contributions of local and landscape factors, and of spatial structure on the regional distribution of both the Lusitanian (Microtus lusitanicus Gerbe, 1879) and Mediterranean pine voles (Microtus duodecimcostatus de Selys-Longchamps, 1839) over an area of 1613 km 2 within a Mediterranean landscape in central Portugal. Three sets of explanatory variables (20 local, 23 landscape, and 6 spatial) were analysed independently by means of a generalized linear model, followed by a variance partitioning procedure. Variance in the distribution patterns of M. lusitanicus and M. duodecimcostatus largely was explained by fine-scale environmental factors but spatial effects also were important, especially for the distribution of M. duodecimcostatus. The close proximity of verges and the high abundance of humidity and coarse sand in the soil were the most influencing local-scale factors for the presence of M. lusitanicus; meanwhile on a larger scale, the high abundance of linear habitats was the main landscape feature determining its occurrence. Regarding the presence of M. duodecimcostatus, the close proximity of verges, high tree canopy cover and herbaceous vegetation biomass were the most influential local explanatory variables for its occurrence, while the absence of shrubs in the surrounding habitat was the main factor regulating species presence at a landscape scale. Similarities identified between the two species primarily were related to descriptors of cover, food and burrows, while differences were related to opposing spatial trends and coarse-scale descriptors

    Spatial and temporal ecology of the Lusitanian pine vole ( Microtus lusitanicus ) in a Mediterranean polyculture

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    In this study we report the fi rst data on the spatial ecology of the Lusitanian pine vole ( Microtus lusitanicus ). Data report to the breeding season and to a traditional Mediterranean agricultural landscape in Central Portugal, using radio-telemetry methods. We documented large home range areas with values of 1042 m 2 for males and 862 m2 for females (MCP method; 95% kernel method with values of 229 m 2 and 159 m 2 for males and females, respectively). Although no signifi cant diff erences between sexes or reproductive status were found, longer daily movements were observed in reproductively inactive males. Pair bonding and home range overlap was observed between males and females, as well as between females and sub-adults. Voles showed no distinct preference for day or night for activity periods and movements. However, this result was dependent on sex, reproductive status and time of day. Voles revealed habitat preference for both spatial scales of analysis: they selected verges, vines and olives, within the study area, and used more verges within their home ranges, when compared to the other habitat types. The use of space by Microtus lusitanicus, in comparison with other microtines, suggests the occurrence of spatial associations between males and females in monogamous pairs. The importance of verges and linear habitats within an agricultural context is apparent, once they provide food and shelter from predators and human interventions

    VEGETATION STRUCTURE AND COMPOSITION OF ROAD VERGE AND MEADOW SITES COLONIZED BY CABRERA VOLE (MICROTUS CABRERAE THOMAS)

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    This paper analyses the floristic composition and vegetation structure in road verge and meadow sites colonized by Cabrera vole (Microtus cabrerae Thomas, 1906), a threatened rodent with fragmented distribution in the Iberian Peninsula. Vegetation was sampled in 26 colonized patches in five geographical areas of Southern Portugal. The cover of the herbaceous layer was sampled in 1 × 1 m plots. Several variables related to plant diversity, Raunkiaer lifeforms, taxonomic groups, disturbance and soil properties were assessed. Floristic composition of the herbaceous communities of road verge and meadow sites was different. Indicator species of road verges corresponded mainly to annual grasses and forbs, ruderal and nitrophilous species, along with a few perennials. In meadows, perennial grasses and moisture indicative species were more common. Results suggest that road verges are lower quality habitats for Cabrera vole maintenance, due to high disturbance, low moisture availability during summer and reduced patch surface. Nevertheless, they might provide benefits such as extra foraging and refuge, especially in disturbed areas. Potential ecological effects of road verge management are discussed in the light of species conservation goals

    Vegetation analysis in colonies of an endangered rodent, the Cabrera vole (Microtus cabrerae), in southern Portugal

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    The Cabrera vole (Microtus cabrerae) is a threatened rodent endemic in the Iberian Peninsula with a patchy distribution and specific microhabitat requirements. This aim of this study was to document the composition of plant communities in habitats of Cabrera vole colonies in southern Portugal. Differences observed in plant species composition were also compared with vegetation structure, taxonomic and life form groups, species and group diversity, disturbance,topography and soil properties. Vegetation was sampled between March and July 2004, in 26 colonies occurring in five geographical areas. Grasses were the most abundant, common and diverse family in the colonies, and the perennial grass Agrostis castellana was present in 92% of colonies, with a mean cover of 16% of the site. Other frequently occurring species were Briza maxima (85%), Vulpia myuros (85%), Gaudinia fragilis (81%), Leontodon spp. (81%), Avena barbata (77%), Bromus hordeaceus (77%) and Tolpis barbata (77%). Colonies were classified in eight vegetation groups that included meadows, tall perennial grasslands, manured meadows with tall sedges, annual grasslands and ruderal and nitrophilous grasslands. Main gradients associated with composition differences were grass richness, annual and perennial grass cover, vegetation structure (herbaceous vegetation height), soil properties (texture and moisture), disturbance (ruderal species) and colony dimensions (area). Results suggest that the Cabrera vole is able to exploit a wide variety of grasslands, with a varying degree of ecological disturbance. Meadows and perennial grassland communities seem to be higher quality microhabitats for voles
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