27,718 research outputs found

    Revisão taxonómica do género Calendula L. (Asteraceae - Calenduleae) na Península Ibérica e Marrocos

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    The genus Calendula L. (Asteraceae - Calenduleae) includes, depending on the author, 10 to 25 species, distributed mainly in the Mediterranean basin. The taxonomy of this genus is considered to be extremely difficult, due to a great morphological variability, doubtfull relevance of some of the characters used to distinguish its species (e.g. the life form: annual or perennial; the habit: erect or diffuse, shape of the leaves, indumentum, relative size of the capitula and colour of disc or ray florets, achene morphology), but also due to the hybridization and polyploidization. Despite the numerous studies that have been published, no agreement on the classification and characters used to discriminate between taxa has been reached. A taxonomic study of the genus Calendula was conducted for the Iberian Peninsula and Morocco, aiming at (1) access the morphological variability between and within taxa, (2) confirm the chromosome numbers, (3) increase the nuclear DNA content estimations, (4) re-evaluate taxa delimitations and circumscription, and (5) reassess, and redefine, the descriptions and characters useful to distinguish taxa. In order to achieve a satisfying taxonomic core, extensive fieldwork, detailed morphometric analysis, chorological, karyological and genome size studies were conducted. For the Iberian Peninsula, four species were recognized, including nine subspecies (between these two new subspecies were described). For Morocco, including some taxa from Algeria and Tunisia 13 species were recognized (two new species and a nomenclatural change), including 15 subspecies (among these eight new subspecies were described). To corroborate the results obtained and to evaluate the evolutionary relationships among taxa, phylogenetic studies using molecular methods, such as ITS, microsatellites or other molecular markers, should be used.O género Calendula L. (Asteraceae - Calenduleae) inclui, dependendo do autor, 10 a 25 espécies, distribuídas essencialmente na bacia do Mediterrâneo. A taxonomia deste género é considerada extremamente difícil, devido à grande variabilidade morfológica, discutivel relevância de alguns dos caracteres utilizados para distinguir suas espécies (por exemplo, a forma de vida: anual ou perene, o hábito: erecto ou difuso, a forma das folhas, o indumento, o tamanho e a cor dos capítulos e a morfologia dos aquénios), mas também devido à hibridização e poliploidização. Apesar dos inúmeros estudos que foram publicados, não foi alcançado um acordo sobre a classificação e os caracteres utilizados para discriminar as suas espécies. Um estudo taxonómico do género Calendula foi realizado para a Península Ibérica e Marrocos, com o objectivo de (1) verificar a variabilidade morfológica, (2) confirmar o número de cromossomas, (3) aumentar as estimativas de conteúdo em ADN, (4) reavaliar a delimitação e a circunscrição dos taxa, e (5) reavaliar e redefinir as descrições e caracteres úteis para os distinguir. Para alcançar uma robustês taxonómica satisfatória, foram realizados extensos trabalhos de campo, análise morfométrica detalhada, abordagens corológicas, cariológicas e quanto ao conteúdo em ADN. Para a Península Ibérica, quatro espécies foram reconhecidas, incluindo nove subespécies (entre essas duas novas subespécies foram descritas). Para Marrocos, incluindo alguns taxa da Argelia e Tunisia, foram reconhecidas 13 espécies (duas novas e uma mudança nomenclatural), incluindo 15 subespécies (entre essas oito novas subespécies foram descritas). Para corroborar os resultados obtidos e avaliar as relações evolutivas e filogenéticas entre os taxa, estudos que utilizem diferentes métodos moleculares, tais como ITS, microsatélites ou outros marcadores moleculares, devem ser utilizados.Apoio financeiro do Laboratório Associado CESAM - Centro de Estudos do Ambiente e do Mar (AMB/50017) financiado por fundos nacionais através da FCT/MCTES e cofinanciado pelo FEDER (POCI-01-0145-FEDER-007638), no âmbito do Acordo de Parceria PT2020, e Compete 2020Programa Doutoral em Biologi

    Phylogeography and evolutionary patterns in Atlanto-Mediterranean butterflies: A hotspot of biodiversity in the context of global change

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    Palaearctic butterflies are among the best studied organisms in the world due to their usefulness as bioindicators of climate and habitat change, relatively resolved identification and appreciation by the general public. Yet, many aspects of their biogeography and evolution remain unknown and novel, integrative research lines have proven useful at resolving old taxonomic uncertainties, at unveiling cryptic species or explaining how evolution has generated current diversity patterns. The Atlanto-Mediterranean area is the ideal laboratory where to study these phenomena. It encompasses the Iberian Peninsula and nearby southern France and the extreme north of Africa, and clearly stands-out as a hotspot of this diversity, combining both ancient lineages which survived major climatic and geological changes of the last 15 My, and newly arrived ones or recently differentiated forms. But to what extent have these butterflies been affected by changing geology and past climate phenomena and how has the partitioned character of the Atlanto-Mediterranean region affected the distribution of genetic diversity? While the possibilities are almost endless, in this thesis we chose three different endemic focal groups of butterflies so as to explore all these aspects and infer biogeographic patterns translational to a wider biotic community: 1) the Portuguese Dappled-White (Euchloe tagis, Pieridae) suffered from taxonomic oversplitting and uncertain phylogenetic placement whereas 2) the mechanisms and tempo of differentiation of too often considered conspecific Sooty-Coppers in Iberia (Lycaenidae) the widespread European Lycaena tityrus and its Iberian endemic counterpart Lycaena bleusei were in need of resolution after decades of uncertainty and conflicting published information. Finally, with project 3) we took the opportunity given by Argeformia Marbled-White butterflies (Nymphalidae, Satyrinae) to resolve the relationships among all taxa in the group and test the effect of major barriers to gene flow within the Atlanto-Mediterranean and beyond. Throughout all these projects, a broad integrative approach was preferred, including as much information as possible, but fundamentally coupling various genetic approaches using independent markers (mtDNA, nuDNA – all projects) under phylogenetic and phylogeographic frameworks and the inference of divergence-times among lineages, with one or several other tools such as up-to-date distribution of conflictive taxa (Lycaena, Melanargia), species distribution modelling (Lycaena, Melanargia), geometric morphometrics (Lycaena) and morphological analysis (Euchloe, Lycaena). While each case-study and methodology delivered interesting outputs at the taxonomic, evolutionary and biogeographic levels, contributing for the resolution of long-standing uncertainties regarding these butterflies, they may also be used in tandem to define broader biodiversity and evolutionary patterns. For instance, the case study of Euchloe tagis unveiled the Iberian Peninsula as a major reservoir of genetic diversity for this exceedingly old species and the Messinian Salinity Crisis (MSC) as a fracturing event in the divergence of populations in the Maghreb and Europe but we found the barrier imposed by the Gibraltar Strait is not fully impermeable and the Rif mountains of Morocco may have been back-colonised from Iberia after the MSC. In the case of Sooty-Coppers (Lycaena tityrus and L. bleusei), not only the very thorough analyses permitted a clear distribution, ecological, morphological and genetic distinction between them, it was also possible to infer their differentiation to be much older than hypothesized previously, raising new questions. With Argeformia Marbled-Whites, it was possible to identify the MSC and later Glacial-Interglacial cycles as major drivers of fundamentally allopatric differentiation, with interesting biogeographic connections such as Sicily with the Maghreb (M. occitanica), the contrasting fates of populations of both Maghrebian species (ines and occitanica) versus their mainland European counterparts, the isolation of M. arge in Italy and all their refugia across time. Globally, these results constitute a major improvement regarding previous knowledge on the evolutionary relationships, taxonomy, stages of differentiation, ecology and chronology of cladogenesis in European butterflies, and particularly in the rich and important assemblage constituted by Atlanto-Mediterranean species. This becomes particularly relevant in the current context of accelerated climate-change, Man-made habitat depletion and the need to conserve genetic diversity for future generations

    Genome-wide phylogeography reveals cryptic speciation in the circumglobal planktonic calcifier Limacina bulimoides.

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    Little is known about when and how planktonic species arise and persist in the open ocean without apparent dispersal barriers. Pteropods are planktonic snails with thin shells susceptible to dissolution that are used as bio-indicators of ocean acidification. However, distinct evolutionary units respond to acidification differently and defining species boundaries is therefore crucial for predicting the impact of changing ocean conditions. In this global population genomic study of the shelled pteropod Limacina bulimoides, we combined genetic (759,000 single nucleotide polymorphisms) and morphometric data from 161 individuals, revealing three major genetic lineages (FST = 0.29 to 0.41): an 'Atlantic lineage' sampled across the Atlantic, an 'Indo-Pacific lineage' sampled in the North Pacific and Indian Ocean, and a 'Pacific lineage' sampled in the North and South Pacific. A time-calibrated phylogeny suggests that the lineages diverged about one million years ago, with estimated effective population size remaining high (~10 million) throughout Pleistocene glacial cycles. We do not observe any signatures of recent hybridisation, even in areas of sympatry in the North Pacific. While the lineages are reproductively isolated, they are morphologically cryptic, with overlapping shell shape and shell colour distributions. Despite showing that the circumglobal L. bulimoides consists of multiple species with smaller ranges than initially thought, we found that these pteropods still possess high levels of genetic variability. Our study adds to the growing evidence that speciation is often overlooked in the open ocean, and suggests the presence of distinct biological species within many other currently defined circumglobal planktonic species

    Location Reference Recognition from Texts: A Survey and Comparison

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    A vast amount of location information exists in unstructured texts, such as social media posts, news stories, scientific articles, web pages, travel blogs, and historical archives. Geoparsing refers to recognizing location references from texts and identifying their geospatial representations. While geoparsing can benefit many domains, a summary of its specific applications is still missing. Further, there is a lack of a comprehensive review and comparison of existing approaches for location reference recognition, which is the first and core step of geoparsing. To fill these research gaps, this review first summarizes seven typical application domains of geoparsing: geographic information retrieval, disaster management, disease surveillance, traffic management, spatial humanities, tourism management, and crime management. We then review existing approaches for location reference recognition by categorizing these approaches into four groups based on their underlying functional principle: rule-based, gazetteer matching–based, statistical learning-–based, and hybrid approaches. Next, we thoroughly evaluate the correctness and computational efficiency of the 27 most widely used approaches for location reference recognition based on 26 public datasets with different types of texts (e.g., social media posts and news stories) containing 39,736 location references worldwide. Results from this thorough evaluation can help inform future methodological developments and can help guide the selection of proper approaches based on application needs

    Protective effects and mechanisms of ellagic acid on intestinal injury in piglets infected with porcine epidemic diarrhea virus

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    The present study was conducted to decipher the protection effects of ellagic acid (EA) on piglets infected with porcine epidemic diarrhea virus (PEDV). Thirty 7-day-old piglets were randomly assigned to three treatment groups: control, PEDV, and EA + PEDV groups. After a 3-day period of adaption, piglets in the EA + PEDV group were orally administered with 20 mg/kg·BW EA during days 4-11 of the trial. On day 8, piglets were orally administered with PEDV at a dose of 106 TCID50 (50% tissue culture infectious dose) per pig. Additionally, intestinal porcine epithelial (IPEC-1) cells infected with PEDV were used to investigate the anti-PEDV effect of EA in vitro. The results showed that EA at a dose of 10-40 μmol/L increased the viability of PEDV-infected IPEC-1 cells, and EA administration mitigated intestinal edema in piglets challenged with PEDV. Further studies indicated that EA treatment significantly increased the proportion of white blood cells in blood and concentrations of IL-6, IL-1β, and IL-10 in the serum, but decreased the TNF-α content and gene expression of IL-6, IL-1β, TNF-α, and CXCL2 in the jejunum. Moreover, EA intervention considerably elevated the activity of total superoxide dismutase (T-SOD), but decreased the H2O2 concentration in the ileum of piglets. Importantly, EA suppressed the increased expression of antiviral-related genes and proteins (including MXI, ISG15, HSP70, and p-IRF7) induced by PEDV challenge in the jejunum. Furthermore, PEDV infection increased the protein abundance of p-JAK2 and p-STAT3, which were further enhanced by EA supplementation. In conclusion, our results revealed that EA could promote the restoration of intestinal homeostasis by regulating the interferon pathway that was interrelated with the activation of JAK2/STAT3 signaling. These findings provide theoretical basis for the use of EA as a therapy targeting PEDV infection in piglets

    Standing genetic variation as a potential mechanism of novel cave phenotype evolution in the freshwater isopod, Asellus aquaticus

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    Novel phenotypes can come about through a variety of mechanisms including standing genetic variation from a founding population. Cave animals are an excellent system in which to study the evolution of novel phenotypes such as loss of pigmentation and eyes. Asellus aquaticus is a freshwater isopod crustacean found in Europe and has both a surface and a cave ecomorph which vary in multiple phenotypic traits. An orange eye phenotype was previously revealed by F2 crosses and backcrosses to the cave parent within two examined Slovenian cave populations. Complete loss of pigmentation, both in eye and body, is epistatic to the orange eye phenotype and therefore the orange eye phenotype is hidden within the cave populations. Our goal was to investigate the origin of the orange eye alleles within the Slovenian cave populations by examining A. aquaticus individuals from Slovenian and Romanian surface populations and Asellus aquaticus infernus individuals from a Romanian cave population. We found orange eye individuals present in lab raised surface populations of A. aquaticus from both Slovenia and Romania. Using a mapping approach with crosses between individuals of two surface populations, we found that the region known to be responsible for the orange eye phenotype within the two previously examined Slovenian cave populations was also responsible within both the Slovenian and the Romanian surface populations. Complementation crosses between orange eye Slovenian and orange eye Romanian surface individuals suggest that the same gene is responsible for the orange eye phenotype in both surface populations. Additionally, we observed a low frequency phenotype of eye loss in crosses generated between the two surface populations and also in the Romanian surface population. Finally, in a cave population from Romania, A. aquaticus infernus, we found that the same region is also responsible for the orange eye phenotype as the Slovenian cave populations and the Slovenian and Romanian surface populations. Therefore, we present evidence that variation present in the cave populations could originate from standing variation present in the surface populations and/or transgressive hybridization of different surface phylogenetic lineages rather than de novo mutations
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