23 research outputs found

    The dual role of Amazonian rivers in the generation and maintenance of avian diversity

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    Copyright © 2018 The Authors. The Amazon River and its major tributaries delimit the distributions of hundreds of terrestrial taxa. It remains unclear whether river-bounded distributions and taxon replacements reflect the historical role of rivers in generating species diversity as vicariant forces, or are the result of their role as secondary barriers, maintaining current levels of species diversity by inhibiting gene flow and population introgression. We use a community-wide comparative phylogeographic and phylogenetic approach to address the roles that the Rio Negro and the Rio Branco play in the avian speciation process in the Guiana Shield. Examining 74 pairs of ecologically similar geographic replacements that turn over across the lower Negro, we found substantial variation in the levels of genetic divergence and the inferred timing of diversification among pairs, ranging from ~0.24 to over 8 million years (Ma ago). The breadth of this variation is inconsistent with a single, shared speciation event. Coalescent simulations also rejected a simultaneous divergence scenario for pairs divided by the Rio Branco but could not reject a single diversification pulse for a subset of 12 pairs of taxa divided by the upper Negro. These results are consistent with recent geomorphological hypotheses regarding the origins of these rivers. Phylogenetically, taxon pairs represent a blend of sister (~40%) and nonsister taxa (~60%), consistent with river-associated allopatric or peripatric speciation and secondary contact, respectively. Our data provide compelling evidence that species turnover across the Rio Negro basin encompasses a mixture of histories, supporting a dual role for Amazonian rivers in the generation and maintenance of biological diversity

    Annotated checklist of the birds of Brazil by the Brazilian Ornithological Records Committee-second edition

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    An updated version of the checklist of birds of Brazil is presented, along with a summary of the changes approved by the Brazilian Ornithological Records Committee's Taxonomy Subcommittee since the first edition, published in 2015. In total, 1971 bird species occurring in Brazil are supported by documentary evidence and are admitted to the Primary List, 4.3% more than in the previous edition. Eleven additional species are known only from undocumented records (Secondary List). For each species on the Primary List, status of occurrence in the country is provided and, in the case of polytypic species, the respective subspecies present in Brazilian territory are listed. Explanatory notes cover taxonomic changes, nomenclatural corrections, new occurrences, and other changes implemented since the last edition. Ninety species are added to the Primary List as a result of species descriptions, new occurrences, taxonomic splits, and transfers from the Secondary List due to the availability of documentation. In contrast, eight species are synonymized or assigned subspecific status and thus removed from the Primary List. In all, 293 species are endemic to Brazil, ranked third among the countries with the highest rate of bird endemism. The Brazilian avifauna currently consists of 1742 residents or breeding migrants, 126 seasonal non-breeding visitors, and 103 vagrants. The category of vagrants showed the greatest increase (56%) compared to the previous list, mainly due to new occurrences documented in recent years by citizen scientists. The list updates the diversity, systematics, taxonomy, scientific and vernacular nomenclature, and occurrence status of birds in Brazil.Peer reviewe

    Potent antitumoral activity of TRAIL through generation of tumor-targeted single-chain fusion proteins

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    In an attempt to improve TRAIL's (tumor necrosis factor-related apoptosis-inducing ligand) tumor selective activity a variant was designed, in which the three TRAIL protomers are expressed as a single polypeptide chain (scTRAIL). By genetic fusion with a single-chain antibody fragment (scFv) recognizing the extracellular domain of ErbB2, we further equipped scTRAIL with tumor-targeting properties. We studied tumor targeting and apoptosis induction of scFv–scTRAIL in comparison with non-targeted scTRAIL. Importantly, the tumor antigen-targeted scTRAIL fusion protein showed higher apoptotic activity in vitro, with a predominant action by TRAIL-R2 signaling. Pharmacokinetic studies revealed increased plasma half-life of the targeted scTRAIL fusion protein compared with scTRAIL. In vivo studies in a mouse tumor model with xenotransplanted Colo205 cells confirmed greater response to the ErbB2-specific scTRAIL fusion protein compared with non-targeted scTRAIL both under local and systemic application regimen. Together, in vitro and in vivo data give proof of concept of higher therapeutic activity of tumor-targeted scFv–scTRAIL molecules. Further, we envisage that through targeting of scTRAIL, potential side effects should be minimized. We propose that scFv-mediated tumor targeting of single-chain TRAIL represents a promising strategy to improve TRAIL's antitumoral action and to minimize potential unwanted actions on normal tissues

    ATLANTIC BIRDS: a data set of bird species from the Brazilian Atlantic Forest

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    South America holds 30% of the world's avifauna, with the Atlantic Forest representing one of the richest regions of the Neotropics. Here we have compiled a data set on Brazilian Atlantic Forest bird occurrence (150,423) and abundance samples (N = 832 bird species; 33,119 bird individuals) using multiple methods, including qualitative surveys, mist nets, point counts, and line transects). We used four main sources of data: museum collections, on-line databases, literature sources, and unpublished reports. The data set comprises 4,122 localities and data from 1815 to 2017. Most studies were conducted in the Florestas de Interior (1,510 localities) and Serra do Mar (1,280 localities) biogeographic sub-regions. Considering the three main quantitative methods (mist net, point count, and line transect), we compiled abundance data for 745 species in 576 communities. In the data set, the most frequent species were Basileuterus culicivorus, Cyclaris gujanensis, and Conophaga lineata. There were 71 singletons, such as Lipaugus conditus and Calyptura cristata. We suggest that this small number of records reinforces the critical situation of these taxa in the Atlantic Forest. The information provided in this data set can be used for macroecological studies and to foster conservation strategies in this biodiversity hotspot. No copyright restrictions are associated with the data set. Please cite this Data Paper if data are used in publications and teaching events. © 2017 by the Ecological Society of Americ

    Pervasive gaps in Amazonian ecological research

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    AVONET: morphological, ecological and geographical data for all birds

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    Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species‐level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity

    Stimmliche Variation in Relation zur genetischen Struktur bei einer Baumsteigerart (Xiphorhynchus fuscus) atlantischer Wälder und ihre Bedeutung für Evolution und Taxonomie

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    The analysis of intra-specifc geographical variation is central to the study of the evolutionary and speciation processes, providing insights into the mechanisms leading to current diversity patterns. In the last decades, analyses of within-species variation moved its focus from phenotypic traits to the analysis of variation in genetic markers. Modern phylogeographic studies could be signifcantly improved by including detailed phenotypic variation analyses, allowing a better understanding of the biological processes driving similar or opposing patterns in phenotype and molecular markers diferentiation. Here, we analyze vocal variation within the Lesser Woodcreeper (Xiphorhynchus fuscus), an Atlantic forest suboscine passerine, in relation to the genetic lineages previously described for this species. Our results show that two of the genetic clades within this species have their own vocal type, while the other two lineages share a common type. This fnding supports the notion that the same events which modeled part of the genetic structure within X. fuscus also led to the accumulation of vocal differences. It also provides evidence to support the elevation of the subspecies atlanticus to a species-level taxon.Für Studien der Evolution und von Artbildungsprozessen ist die Untersuchung intraspezifischer geografischer Variation von zentraler Bedeutung und ermöglicht Rückschlüsse auf die Mechanismen, welche zu den derzeitigen Diversitätsmustern geführt haben. Bei Analysen innerartlicher Variation hat sich während der letzten Jahrzehnte der Schwerpunkt von phänotypischen Merkmalen zur Analyse der Variation genetischer Marker verlagert. Die Einbeziehung detaillierter Analysen phänotypischer Variation wäre ein signifikanter Gewinn für heutige phylogeografische Untersuchungen und würde zu einem besseren Verständnis der biologischen Prozesse führen, welche ähnliche oder entgegengesetzte Muster bei der Differenzierung phänotypischer und molekularer Marker entstehen lassen. Hier untersuchen wir die stimmliche Variation beim Blasskehl-Baumsteiger (Xiphorhynchus fuscus), einer suboszinen Singvogelart atlantischer Wälder, in Relation zu den bisher beschriebenen genetischen Abstammungslinien für diese Art. Unsere Ergebnisse zeigen, dass zwei der genetischen Kladen innerhalb der Art ihren eigenen Stimmtyp besitzen, während sich die zwei übrigen Abstammungslinien einen gemeinsamen Typ teilen. Dies bestätigt die Theorie, dass dieselben Ereignisse, welche Teile der genetischen Struktur innerhalb von X. fuscus geprägt haben, auch zur Herausbildung stimmlicher Unterschiede geführt haben. Außerdem dient dies als Beleg zur Untermauerung der Erhebung der Unterart atlanticus zu einem Taxon auf Artebene.Fil: García, Natalia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Naka, Luciano N.. Universidade Federal de Pernambuco; BrasilFil: Cabanne, Gustavo Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentin
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