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Background: Incomplete species inventories for Antarctica represent a key challenge for comprehensive ecological research and conservation in the region. Additionally, data required to understand population dynamics, rates of evolution, spatial ranges, functional traits, physiological tolerances and species interactions, all of which are fundamental to disentangle the different functional elements of Antarctic biodiversity, are mostly missing. However, much of the fauna, flora and microbiota in the emerged ice-free land of the continent have an uncertain presence and/or unresolved status, with entire biodiversity compendia of prokaryotic groups (e.g. bacteria) being missing. All the available biodiversity information requires consolidation, cross-validation, re-assessment and steady systematic inclusion in order to create a robust catalogue of biodiversity for the continent. New information: We compiled, completed and revised eukaryotic species inventories present in terrestrial and freshwater ecosystems in Antarctica in a new living database: terrANTALife (version 1.0). The database includes the first integration in a compendium for many groups of eukaryotic microorganisms. We also introduce a first catalogue of amplicon sequence variants (ASVs) of prokaryotic biodiversity. Available compendia and literature to date were searched for Antarctic terrestrial and freshwater species, integrated, taxonomically harmonised and curated by experts to create comprehensive checklists of Antarctic organisms. The final inventories comprises 470 animal species (including vertebrates, free-living invertebrates and parasites), 306 plants (including all Viridiplantae: embryophytes and green algae), 997 fungal species and 434 protists (sensu lato). We also provide a first account for many groups of microorganisms, including non-lichenised fungi and multiple groups of eukaryotic unicellular species (Stramenophila, Alveolata and Rhizaria (SAR), Chromists and Amoeba), jointly referred to as "protists". In addition, we identify 1753 bacterial (obtained from 348117 ASVs) and 34 archaeal genera (from 1848 ASVs), as well as, at least, 14 virus families. We formulate a basic tree of life in Antarctica with the main lineages listed in the region and their "known-accepted-species" numbers.
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Great environmental changes may affect the survival capability of a variety of organisms. Testudinidae is the most diverse family of terrestrial chelonians within the whole order (Testudines). Interestingly, however, the number of extinct species overcome the extant ones. In order to understand better how the diversification process of this family occurred, this work used the PyRate software, which estimates both the preservation and diversification processes in a continuous time interval. For such, the software used a list of fossil occurrences obtained from the Paleobiology Database whereas the extant species list was obtained from Catalogue of Life. This way, the software was able to infer the probability of the ancestral clade having resulted in these species during its evolutionary history. The analyses generated graphs containing the diversification, extinction and speciation curves and their respective associated 95% credibility intervals. A great rise in the extinction rate was observed starting 6 million years ago. This rise is believed to be related to the drop of atmospheric CO2 all over the globe at the end of the Miocene, about 8-6 million years ago. This event led to a turnover of the vegetation composition on the warmer areas of the planet, with plants that used C3 metabolism giving way to C4 plants. In terms of landscape, grasses and herbal vegetation, such as savannas, started dominating. As for other animal groups, those herbivores with grazing habits were more successful than those used to only browsing or that did not have enough flexibility of choice.
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Tortugas , Animales , Filogenia , Evolución Biológica , FósilesRESUMEN
Body size and shape fundamentally determine organismal energy requirements by modulating heat and mass exchange with the environment and the costs of locomotion, thermoregulation, and maintenance. Ecologists have long used the physical linkage between morphology and energy balance to explain why the body size and shape of many organisms vary across climatic gradients, e.g., why larger endotherms are more common in colder regions. However, few modeling exercises have aimed at investigating this link from first principles. Body size evolution in bats contrasts with the patterns observed in other endotherms, probably because physical constraints on flight limit morphological adaptations. Here, we develop a biophysical model based on heat transfer and aerodynamic principles to investigate energy constraints on morphological evolution in bats. Our biophysical model predicts that the energy costs of thermoregulation and flight, respectively, impose upper and lower limits on the relationship of wing surface area to body mass (S-MR), giving rise to an optimal S-MR at which both energy costs are minimized. A comparative analysis of 278 species of bats supports the model's prediction that S-MR evolves toward an optimal shape and that the strength of selection is higher among species experiencing greater energy demands for thermoregulation in cold climates. Our study suggests that energy costs modulate the mode of morphological evolution in batshence shedding light on a long-standing debate over bats' conformity to ecogeographical patterns observed in other mammalsand offers a procedure for investigating complex macroecological patterns from first principles.
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Regulación de la Temperatura Corporal , Quirópteros , Vuelo Animal , Alas de Animales , Animales , Fenómenos Biofísicos , Tamaño Corporal , Quirópteros/anatomía & histología , Quirópteros/fisiología , Clima , Vuelo Animal/fisiología , Alas de Animales/anatomía & histología , Alas de Animales/fisiologíaRESUMEN
AbstractContinental mountain areas cover <15% of global land surface, yet these regions concentrate >80% of global terrestrial diversity. One prominent hypothesis to explain this pattern proposes that high mountain diversities could be explained by higher diversification rates in regions of high topographic complexity (HTC). While high speciation in mountains has been detected for particular clades and regions, the global extent to which lineages experience faster speciation in mountains remains unknown. Here we addressed this issue using amphibians as a model system (>7,000 species), and we found that families showing high speciation rates contain a high proportion of species distributed in mountains. Moreover, we found that lineages inhabiting areas of HTC speciate faster than lineages occupying areas that are topographically less complex. When comparing across regions, we identified the same pattern in five biogeographical realms where higher speciation rates are associated with higher levels of complex topography. Low-magnitude differences in speciation rates between some low and high complex topographies suggest that high mountain diversity is also affected by low extinction and/or high colonization rates. Nevertheless, our results bolster the importance of mountains as engines of speciation at different geographical scales and highlight their importance for the conservation of global biodiversity.
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Biodiversidad , Especiación Genética , Anfibios , Animales , Humanos , FilogeniaRESUMEN
The origin of morphological diversity is a critical question in evolutionary biology. Interactions between the environment and developmental processes have determining roles in morphological diversity, creating patterns through space and over time. Also, the shape of organisms tends to vary with increasing size as a result of those developmental processes, known as allometry. Several studies have demonstrated that the body sizes of anurans are associated with hydric conditions in their environments and that localities with high water stress tend to select for larger individuals. However, how environmental conditions alter those patterns of covariance between size and shape is still elusive. We used 3D geometric morphometric analyses, associated with phylogenetic comparative methods, to determine if the morphological variations and allometric patterns found in Arboranae (Anura) is linked to water conservation mechanisms. We found effects of the hydric stress on the shape of Arboranae species, favouring globular shapes. Also, the allometric patterns varied in intensity according to the water stress gradient, being particularly relevant for smaller frogs, and more intense in environments with higher water deficits. Our study provides empirical evidence that more spherical body shapes, especially among smaller species, reflect an important adaptation of anurans to water conservation in water-constrained environments.
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Anuros/anatomía & histología , Anuros/metabolismo , Tamaño Corporal/fisiología , Agua/metabolismo , Animales , Evolución Biológica , Filogenia , Cráneo/anatomía & histología , Cráneo/metabolismoRESUMEN
Evolutionary rate explanations for latitudinal diversity gradients predict faster speciation and diversification rates in richer, older and more stable tropical regions (climatic stability hypothesis). Numerous modern lineages have emerged in high latitudes, however, suggesting that climatic oscillations can drive population divergence, at least among extratropical species (glacial refugia hypothesis). This conflicting evidence suggests that geographical patterns of evolutionary rates are more complicated than previously thought. Here, we reconstructed the complex evolutionary dynamics of a comprehensive data set of modern mammals, both terrestrial and marine. We performed global and regional regression analyses to investigate how climatic instability could have indirectly influenced contemporary diversity gradients through its effects on evolutionary rates. In particular, we explored global and regional patterns of the relationships between species richness and assemblage-level evolutionary rates and between evolutionary rates and climatic instability. We found an inverse relationship between evolutionary rates and species richness, especially in the terrestrial domain. Additionally, climatic instability was strongly associated with the highest evolutionary rates at high terrestrial latitudes, supporting the glacial refugia hypothesis there. At low latitudes, evolutionary rates were unrelated to climatic stability. The inverse relationship between evolutionary rates and the modern latitudinal diversity gradient casts doubt on the idea that higher evolutionary rates in the tropics underlie the current diversity patterns of modern mammals. Alternatively, the longer time spans for diversity to accumulate in the older and more stable tropics (and not high diversification rates) may explain the latitudinal diversity gradient.
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Biodiversidad , Cambio Climático , Especiación Genética , Mamíferos/genética , Animales , Cubierta de Hielo , Filogenia , Clima TropicalRESUMEN
Knowledge of the oribatid mite community from Patagonian steppe is scarce compared with other environments, such as the Andean-Patagonian forest. In the present research we identified oribatid mites under different environmental conditions: two Patagonian steppe types (grass and shrub), two soil characteristics (bare and covered soil) and two different seasons (autumn and spring). A total of 42 species/morphospecies were found, 13 were new records for Chubut and one was a new record for Argentina. In view of its ecological role in soil formation, it is fundamental that knowledge about this fauna is enhanced in order to provide baselines for study and to aid further understanding about its ecology.
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Ácaros , Animales , Argentina , Ecología , Bosques , SueloRESUMEN
Chagas disease represents one of the major health issue in Latin America. Epidemiological control is focused on disease vectors, so studies on the ecology of triatomine vectors constitute a central strategy. Recently, research at large spatial scale has been produced, and authors commonly rely on the assumption that geographical regions presenting good environmental conditions for most vector species are also those with high risk of infection. In the present work, we provide an explicit evaluation for this assumption. Employing species distribution models and epidemiological data for Chagas disease in Brazilian territory, our results show that species richness is a poor predictor for the observed pattern of Chagas disease occurrence. Species composition proved to be a better predictor. We stress that research on macroecology of infectious diseases should go beyond the analysis of biodiversity patterns and consider human infections as a central part of the focal ecological systems.
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Biodiversidad , Enfermedad de Chagas/epidemiología , Monitoreo del Ambiente , Insectos Vectores/parasitología , Triatominae/parasitología , Trypanosoma cruzi/aislamiento & purificación , Animales , Brasil/epidemiología , Enfermedad de Chagas/transmisión , Ecosistema , Humanos , Insectos Vectores/clasificación , Modelos Estadísticos , Triatominae/clasificaciónRESUMEN
Geometric morphometrics were used to analyse ontogenetic trajectories in representatives of the Characiformes, Cichliformes, Cyprinodontiformes, Siluriformes, and Tetraodontiformes. It was not possible to differentiate any allometric growth patterns across groups, indicating that a phylogenetically conserved developmental pattern is widespread throughout Teleostei.
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Evolución Biológica , Peces/crecimiento & desarrollo , Animales , Biometría , Femenino , Masculino , FilogeniaRESUMEN
La infección por citomegalovirus (CMV) es la infección congénita más común, con una incidencia de 0.2 a 2.2 % en los recién nacidos vivos. Del 10 al 15% del los recién nacidos infectados son sintomáticos. Los signos clínicos comunes son ictericia, petequias y hepatoesplenomegalia, además de prematuridad, trombocitopenia y anemia. Él diagnóstico fetal se sospecha por ultra - sonografía y se conirma mediante detección de Ig G en muestra tomadas atreves de cordocentesis o amniocentesis. Descripción del caso: Se presenta caso de una embarazada de 35 años de edad, a quien se le realizo a las 34.3 semanas de gestación cordo - centesis diagnostica, por presentar Hidrops fetal NO INMUNE mas anemia fetal severa diagnósticada por velocidad de pico sistólico de la arteria cerebral media, presentando características ultrasonografías, se realizó transfusión intrautero sin ninguna complicación además se llevó el embarazo al término, la evaluación oftalmológica reporto secuelas maculares características de citomegalovirus...(AU)
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Humanos , Femenino , Embarazo , Anemia/embriología , Transfusión de Sangre Intrauterina , Citomegalovirus , Hidropesía FetalRESUMEN
Herein we review the genus Physobates Hammer, 1962 and redescribe P. spinipes Hammer 1962 based on material collected in Buenos Aires, Argentina. After a morphological comparison among species of Tegoribatidae genera, we propose a new junior synonym, Paraphysobates Mahunka, 1985. A key to identify tegoribatid genera is also provided.
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Ácaros/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Argentina , Tamaño Corporal , Ecosistema , Femenino , Masculino , Ácaros/anatomía & histología , Ácaros/crecimiento & desarrollo , Tamaño de los ÓrganosRESUMEN
Synthesized lipophilic tyrosyl ester derivatives with increasing lipophilicity were effective against Leishmania (L.) major and Leishmania infantum species in vitro. These findings prompted us to test in vivo leishmanicidal properties of these molecules and their potential effect on the modulation of immune responses. The experimental BALB/c model of cutaneous leishmaniasis was used in this study. Mice were infected with L. major parasites and treated with three in vitro active tyrosyl esters derivatives. Among these tested tyrosylcaprate (TyC) compounds, only TyC10 exhibited an in vivo anti-leishmanial activity, when injected sub-cutaneously (s.c.). TyC10 treatment of L. major-infected BALB/c mice resulted in a decrease of lesion development and parasite load. TyC10 s.c. treatment of non-infected mice induced an imbalance in interferon γ/interleukin 4 (IFN-γ/IL-4) ratio cytokines towards a Th1 response. Our results indicate that TyC10 s.c. treatment improves lesions' healing and parasite clearance and may act on the cytokine balance towards a Th1 protective response by decreasing IL-4 and increasing IFN-γ transcripts. TyC10 is worthy of further investigation to uncover its mechanism of action that could lead to consider this molecule as a potential drug candidate.
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Antiprotozoarios/administración & dosificación , Factores Inmunológicos/administración & dosificación , Leishmania major/efectos de los fármacos , Leishmaniasis Cutánea/tratamiento farmacológico , Animales , Citocinas/metabolismo , Modelos Animales de Enfermedad , Inyecciones Subcutáneas , Ratones , Ratones Endogámicos BALB C , Carga de Parásitos , Células TH1/inmunología , Tirosina/análogos & derivados , Tirosina/farmacologíaAsunto(s)
Distribución Animal , Ecosistema , Mamíferos/fisiología , Filogenia , Animales , Modelos BiológicosRESUMEN
El propósito de este estudio fue determinar clínicamente la frecuencia de aparición del segundo conducto radicular mesiovestibulardel primer molar superior y la frecuencia de desembocadura del conducto en uno o más forámenes apicales. Métodos: Se realizó el tratamiento de conducto en 55 pacientes con derivación a endodoncia del primer molar superior permanente, realizado por el mismo operador y utilizando magnificación con microscopio clínico. Se consideró la presencia de uno o más conductos radiculares en la raíz mesiovestibular luego de la instrumentación de los conductos y se determinó el número de forámenes apicales al introducir las limas depermeabilidad apical, simultáneamente, a una longitud mayor a la longitud de trabajo. Se utilizó el método score de Wilson para calcular intervalos de confianza 95 por ciento de porcentajes (IC95). Resultados: Se registró que de los 55 pacientes tratados, la raíz mesiovestibular presentaba, en el 21,82 por ciento [IC95=(12,95 por ciento; 34,37 por ciento)], un solo conducto desembocando en un solo foramen apical, el 30,91 por ciento [IC95=(20,28 por ciento; 44,03 por ciento)] presentaron dos conductos radiculares con un solo foramen apical y el 47,27 por ciento [IC95=(34,69 por ciento;60,21 por ciento)] presentaron dos conductos radiculares con un foramen apical independiente cada conducto. Conclusión: La presencia de un segundo conducto mesiovestibular como así la frecuencia de desembocadura en un foramen apical independiente presentan una alta frecuencia de aparición, por lo tanto, durante la terapia endodontica debe realizarse una exploración minuciosa del piso cameral, en buscade localizar y tratar este conducto, aumentando de esta manera las probabilidades de éxito del tratamiento a largo plazo...
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Adolescente , Adulto , Adulto Joven , Persona de Mediana Edad , Anomalías Dentarias/epidemiología , Cavidad Pulpar/anatomía & histología , Diente Molar/anatomía & histología , Raíz del Diente/anatomía & histología , Distribución por Edad y Sexo , Argentina , Facultades de Odontología , Maxilar , Interpretación Estadística de Datos , Tratamiento del Conducto Radicular/estadística & datos numéricosRESUMEN
The process of preferential chromosome segregation during meiosis has been suggested to be responsible for the predominance of certain chromosome types in the karyotypes of mammals, birds and insects. We developed an extensive analysis of the fixation of mono- or bibrachial chromosomes in the karyotypes of the large Actinopterygii fish group, a key link in the evolution of terrestrial vertebrates, in order to investigate the generality of meiotic drive in determining karyotypic macrotrends. Unlike mammals, fishes have markedly undergone several types of preferential chromosomal rearrangements throughout evolution. Data from the analyzed orders indicate a prevalence of karyotypes with few (<33%) or many (>66%) acrocentric chromosomes and a low number of karyotypes with balanced numbers of mono- and bi-brachial elements. Parallel trends towards a higher number of karyotypes with prevalence of monobrachial chromosomes occurred in phylogenetically close orders (e.g. Perciformes and Tetraodontiformes, and in the order Mugiliformes) and in clades with prevalence of bibrachial elements (e.g. Characiformes, Gymnotiformes, Siluriformes, and Cypriniformes). Some orders where fewer species were available for study, such as Atheriniformes and Anguilliformes, showed karyotype assemblages where both trends were present. Our results strongly suggest a primary role of meiotic drive in karyotypic evolution as indicated by the accumulation of monobrachial chromosomes in Perciformes and Cypriniformes, or bibrachial chromosomes in Siluriformes and Characiformes. Further examinations of the interaction between life history traits, environmental characteristics, and the fixation of chromosomal rearrangements would be exceedingly valuable.
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Segregación Cromosómica/fisiología , Cromosomas/genética , Evolución Molecular , Peces/genética , Cariotipo , Meiosis/fisiología , Animales , Segregación Cromosómica/genética , Meiosis/genética , FilogeniaRESUMEN
Mechanisms of accumulation based on typical centromeric drive or of chromosomes carrying pericentric inversions are adjusted to the general karyotype differentiation in the principal Actinopterygii orders. Here, we show that meiotic drive in fish is also supported by preferential establishment of sex chromosome systems and B chromosomes in orders with predominantly bi-brachial chromosomes. The mosaic of trends acting at an infra-familiar level in fish could be explained as the interaction of the directional process of meiotic drive as background, modulated on a smaller scale by adaptive factors or specific karyotypic properties of each group, as proposed for the orthoselection model.
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Evolución Biológica , Cromosomas/genética , Peces/genética , Cariotipo , Animales , Peces/clasificación , Filogenia , Cromosomas SexualesRESUMEN
A main target in the treatment of hypertension is the angiotensin-converting enzyme (ACE). This enzyme is responsible for producing angiotensin II, a potent vasoconstrictor. Therefore, one of the targets in the treatment of hypertension is to inhibit ACE activity. Hence, this study's aim is to use computational studies to demonstrate that the proposed heterocyclic compounds have a molecular affinity for ACE and that, furthermore, these heterocyclic compounds are capable of inhibiting ACE activity, thus avoiding the production of the vasopressor Angiotensin II. All this using computer-aided drug design, and studying the systems, with the proposed compounds, through molecular recognition process and compared with the compounds already on the market for hypertension.
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1. The variation in cranial size of the crab-eating fox Cerdocyon thous was analysed in relation to latitude and several environmental variables throughout its distribution in South America. 2. We tested the existence of clines to determine whether this canid follows Bergmann's rule to the north and south of the Equator. Also, using niche modelling, we analysed whether the climatic changes during the last glaciation could have influenced Bergmann's rule in this species. We quantified the size of the cranium of C. thous (n = 300). The data were divided into two groups: (i) south of the Equator (n = 163) and (ii) north of the Equator (n = 137). We performed correlations, OLS regressions and simultaneous autoregressions to analyse the relationship between the variation in size and different geographic and environmental variables. Data of occurrence (n = 594) together with ambient variables from the present and the last glacial maximum (LGM) were used to predict the occurrence of C. thous with the implementation of the maximum entropy method. Present-day and historical distribution maps were obtained. 3. The variation in the size of the cranium of C. thous showed two trends. In the south of Equator, we observed that the size of the skull shows an inverse relationship with temperature-related variables and a positive one with precipitation, while in north of the Equator, we observed the opposite relationship. Populations south of the Equator follow Bergmann's rule showing increasing size with increasing latitude. To the north of the Equator, a non-Bergmannian pattern occurs because size decreases with increasing latitude. 4. Niche modelling showed two present-day groupings in South America, one north of Amazonia and the other south. However, for the period of the LGM, four groups emerged, possibly related to the four subspecies presently described for C. thous. Therefore, it is possible that the observed pattern - southern populations following Bergmann's rule while northern populations reflecting the opposite - has been influenced by the events that occurred during the LGM that could have led to the differentiation of populations.
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Distribución Animal/fisiología , Tamaño Corporal/fisiología , Zorros/anatomía & histología , Lluvia , Cráneo/anatomía & histología , Temperatura , Animales , Cambio Climático/estadística & datos numéricos , Geografía , Historia Antigua , Modelos Biológicos , América del SurRESUMEN
We describe for the first time the karyotypes of two species of Cryptodiran turtles from Argentina, namely, Trachemys dorbigni (Emydidae) and Chelonoidis (Geochelone) donosobarrosi (Testudinidae). The karyotype of T. dorbigni (2n = 50) consists of 13 pairs of macrochromosomes and 12 pairs of microchromosomes, whereas the karyotype of C. donosobarrosi (2n = 52) consists of 11 pairs of macrochromosomes and 15 pairs of microchromosomes. Fluorescence in situ hybridization (FISH) with a (TTAGGG)n telomeric probe showed that the chromosomes of these species have four telomeric signals, two at each end, indicating that none of the chromosomes of T. dorbigni and C. donosobarrosi are telocentric. The fact that no interstitial telomeric signals were observed after FISH, suggests that interstitial telomeric sequences did not have a major role in the chromosomal evolution of these species. Additional data will be needed to elucidate if interstitial telomeric sequences have a major role in the karyotypic evolution of Testudines.