Population genetic structure of the Antarctic ascidian Aplidium falklandicum from Scotia Arc and South Shetland Islands

In sessile marine organisms, gene flow between populations depends mainly on free-living reproductive stages (such as larvae and gametes), and usually the strength of genetic structure is related to the time spent in the plankton and physical factors as oceanographic conditions. In Antarctica, abyssal depths that surround the continent and the Polar Front are considered strong barriers for benthic marine fauna, keeping the continent isolated from other shelves. The only available shallow water habitats between South America and the Antarctic continent are those around the Scotia Arc Islands; there are no shallow water habitats between the other southern continents and Antarctica. In this work, ISSRs-PCR markers were used to study the genetic structure of populations of Aplidium falklandicum, a compound ascidian with short-lived lecitotrophic larvae. A highly significant genetic differentiation (ΦST = 0.405; P < 0.05) and a pattern of isolation by distance were found. A genetic landscape approach identified a discontinuity in genetic diversity, coincident with the southernmost registered position of the Polar Front. For A. falklandicum, a species with presumably low capacity of long distance dispersal, the abyssal depths together with the large geographic distances create a barrier for gene flow.Fil: Demarchi, Maria Milagros. Universidad Nacional de Córdoba. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Diversidad Biologica y Ecologica. Cat.de Ecologia Marina; Argentina. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Cátedra de Genética de Poblaciones y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Chiappero, Marina Beatriz. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Cátedra de Genética de Poblaciones y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Tatian, Marcos. Universidad Nacional de Córdoba. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Diversidad Biologica y Ecologica. Cat.de Ecologia Marina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Sahade, Ricardo Jose. Universidad Nacional de Córdoba. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Diversidad Biologica y Ecologica. Cat.de Ecologia Marina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin

The Food Web of Potter Cove (Antarctica): complexity, structure and function

Knowledge of the food web structure and complexity are central to better understand ecosystem functioning. A food-web approach includes both species and energy flows among them, providing a natural framework for characterizing species’ ecological roles and the mechanisms through which biodiversity influences ecosystem dynamics. Here we present for the first time a high-resolution food web for a marine ecosystem at Potter Cove (northern Antarctic Peninsula). Eleven food web properties were analyzed in order to document network complexity, structure and topology. We found a low linkage density (3.4), connectance (0.04) and omnivory percentage (45), as well as a short path length (1.8) and a low clustering coefficient (0.08). Furthermore, relating the structure of the food web to its dynamics, an exponential degree distribution (in- and out-links) was found. This suggests that the Potter Cove food web may be vulnerable if the most connected species became locally extinct. For two of the three more connected functional groups, competition overlap graphs imply high trophic interaction between demersal fish and niche specialization according to feeding strategies in amphipods. On the other hand, the prey overlap graph shows also that multiple energy pathways of carbon flux exist across benthic and pelagic habitats in the Potter Cove ecosystem. Although alternative food sources might add robustness to the web, network properties (low linkage density, connectance and omnivory) suggest fragility and potential trophic cascade effects.Fil: Marina, Tomas Ignacio. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Universidad Nacional de Luján. Instituto de Ecología y Desarrollo Sustentable. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ecología y Desarrollo Sustentable; ArgentinaFil: Salinas, Vanesa Anabella. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cordone, Georgina Florencia. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Campana, Gabriela Laura. Universidad Nacional de Luján. Instituto de Ecología y Desarrollo Sustentable. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ecología y Desarrollo Sustentable; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Moreira, María Eugenia. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Deregibus, Dolores. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Torre, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Sahade, Ricardo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Tatian, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Barrera Oro, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: De Troch, Marleen. University College Ghent; BélgicaFil: Doyle, Santiago Raúl. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Quartino, Maria Liliana. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Saravia, Leonardo Ariel. Universidad Nacional de General Sarmiento. Instituto de Ciencias; ArgentinaFil: Momo, Fernando Roberto. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Universidad Nacional de Luján. Instituto de Ecología y Desarrollo Sustentable. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ecología y Desarrollo Sustentable; Argentin

Mutação do Gene p53 induzindo predisposição hereditária ao câncer: relato de um caso da síndrome de Li-Fraumeni

Li-Fraumeni syndrome is a familiar cancer predisposition syndrome characterized by the appearance of various types of tumors, such as sarcomas, breast carcinomas, brain tumors and leukemia. We present the case of a 37-year-old female who had a strong family history of cancer and herself had a history of six different primary tumors (one colon, one displasic nevus, one ovary and three breast tumors). P53 gene sequencing of her peripheral blood lymphocytes revealed an amino acid change of tryptofan (TGG) to a stop-codon (TAG) in the nucleotide 437 of codon 146 of exon 5 of this gene. Clinical, preventive and ethical implications of this molecular finding are also discussed.A Síndrome de Li-Fraumeni é uma síndrome de predisposição familiar ao câncer, caracterizada pela presença de múltiplos tumores, tais como sarcomas, carcinomas de mama, tumores cerebrais e leucemia. O caso relatado é de uma paciente feminina de 37 anos, que apresenta uma significativa história familiar de câncer, bem como história pessoal de seis diferentes tumores primários (um de cólon, um nevus displásico, um de ovário e três de mama). O seqüenciamento do gene supressor de tumor p53 em seus linfócitos presentes no sangue periférico revelou uma mutação do aminoácido triptofano (TGG) para um códon de parada prematuro (TAG), no nucleotídeo 437 do códon 146 do exon 5 deste gene. As implicações clínicas, preventivas e éticas deste caso são também abordadas

Surgical resection, intraoperative radiotherapy and immediate plastic reconstruction: A good option for the treatment of distal extremity soft tissue sarcomas

AimTo show three patients with soft tissue sarcomas of distal extremities conservatively treated after tumor-board discussion, involving margin-free surgery, exclusive intraoperative radiotherapy, and immediate reconstruction.BackgroundCurrent guidelines show clear and robust recommendations regarding the composition of the treatment of sarcomas of extremities. However, little evidence exists regarding the application of these treatments depending on the location of the primary neoplasia. Tumors that affect the distal extremities present different challenges and make multidisciplinary discussions desirable.Methods/ResultsWe reported 3 patients who were approached with a conservative intention, after tumor board recomendation. The goals from the treatment performed were aesthetic and functional preservation, while enruring locoregional control. We had wound healing complications in 2 of the cases, requiring additional reconstruction measures. Patients are followed up for 24, 20 and 10 months; local control is 100%, and functional preservation is 100%.ConclusionsDespite being a small series, it was sufficient to illustrate successful multidisciplinary planning, generating a therapeutic result with improved quality of life for patients who had an initial indication for extremity amputation

Genetic variability and differentiation among polymorphic populations of the genusSynoicum(Tunicata, Ascidiacea) from the South Shetland Islands

In Antarctica, ascidians are among the most conspicuous and abundant organisms in benthic ecosystems and many species present wide distribution patterns. Two similar forms of ascidians of the colonial genus Synoicum were sampled along the South Shetland Islands, one greenish-yellow with elongated colony stalks and the other yellow-orange with shorter stalks and more rounded colony bodies. The taxonomic analyses indicated that the greenish-yellow form corresponded to the description of the species S. ostentor and the yellow-orange form to that of S. adareanum. However, molecular analyses using the cytochrome oxidase I gene did not detect clear differences between both forms. The frequency and geographic distribution of haplotypes indicate that some degree of gene flow may be occurring, strongly suggesting that both morphotypes did not achieve a complete reproductive isolation yet, that they can still interbreed and should therefore be considered as a single species. Surprisingly, these results are not in line with recent studies of Antarctic fauna using a similar approach, which revealed several cases of morphologically indistinguishable but genetically distinct species.Fil: Wiernes, María Paula. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Diversidad y Ecologia Animal; Argentina. Universidad Nacional de Cordoba. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Diversidad Biologica y Ecologica. Cat.de Ecologia Marina; ArgentinaFil: Sahade, Ricardo Jose. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Diversidad y Ecologia Animal; Argentina. Universidad Nacional de Cordoba. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Diversidad Biologica y Ecologica. Cat.de Ecologia Marina; ArgentinaFil: Tatian, Marcos. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Diversidad y Ecologia Animal; Argentina. Universidad Nacional de Cordoba. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Diversidad Biologica y Ecologica. Cat.de Ecologia Marina; ArgentinaFil: Chiappero, Marina Beatriz. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Diversidad y Ecologia Animal; Argentina. Universidad Nacional de Cordoba. Facultad de Cs.exactas Fisicas y Naturales. Catedra de Genetica de Poblaciones y Evolucion; Argentin

A contribution to the understanding of phylogenetic relationships among species of the genus octopus (Octopodidae: Cephalopoda)

Many species of the genus Octopus are important resources for fisheries worldwide. Its approximately 200 species show a strong similarity in structural morphology and a wide diversity in skin coloration and patterning, behaviour and life strategies that have hampered the study of phylogenetic relationships. We used a Bayesian approach to estimate as yet unknown phylogenetic relationships among O. tehuelchus from the southwestern Atlantic, new specimens of O. mimus (Chile and Peru) and other Octopus species, and used Bayes factors to test phylogenetic hypotheses. O. tehuelchus was more closely related to the genera Callistoctopus, Grimpella and Macroctopus than to Octopus, and therefore its generic placement may need a revision. O. vulgaris specimens from Costa Rica (Pacific Ocean) and O. oculifer grouped with O. mimus. Bayes factors showed positive evidence in favor of this grouping and therefore these individuals could have been misidentified, being in fact O. mimus. O. vulgaris specimens from the Costa Rican Caribbean were more related to O. mimus than to other O. vulgaris and could represent a cryptic species. The remaining O. vulgaris clustered with O. tetricus. Bayes factors found strong evidence against the monophyly of O. vulgaris as currently defined, giving statistical support to the monophyly of an O. vulgaris s. str. + O. tetricus group proposed previously by other authors.Numerosas especies del género Octopus constituyen un recurso importante para las pesquerías en todo el mundo. Sus aproximadamente 200 especies presentan a la vez una importante similitud en morfología y una amplia diversidad en el patrón y coloración de la piel, comportamiento y estrategias de vida, lo cual ha dificultado el estudio de las relaciones filogenéticas. En este trabajo estimamos las relaciones filogenéticas entre O. tehuelchus del Atlántico sudoccidental (cuyas relaciones con otras especies de la subfamilia son desconocidas), nuevos especímenes de O. mimus (Chile y Perú) y otras especies de Octopus, utilizando métodos de estimación bayesiana. Además utilizamos tests de factores de Bayes para comprobar hipótesis filogenéticas. O. tehuelchus estuvo más cercanamente relacionado a los géneros Callistoctopus, Grimpella y Macroctopus que a Octopus, y por lo tanto su ubicación genérica debería ser revisada. Los especímenes de O. vulgaris de Costa Rica (Océano Pacífico) y O. oculifer, se agruparon junto con O. mimus. Los factores de Bayes mostraron evidencia positiva a favor de este agrupamiento, por lo que estos ejemplares podrían representar ejemplares de O. mimus mal clasificados. Los especímenes de O. vulgaris del Mar Caribe de Costa Rica podrían constituir una especie críptica ya que estuvieron más cercanamente relacionados a O. mimus que a los restantes O. vulgaris. Estos últimos se agruparon con O. tetricus. Los factores de Bayes mostraron una fuerte evidencia a favor de este agrupamiento, dando soporte estadístico a la monofilia de O. vulgaris s. str. + O. tetricus propuesta previamente por otros autores.Fil: Acosta Jofré, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Diversidad Biologica y Ecologica. Cat.de Ecologia Marina; ArgentinaFil: Sahade, Ricardo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Diversidad Biologica y Ecologica. Cat.de Ecologia Marina; ArgentinaFil: Laudien, Jürgen. Alfred-Wegener-Institut. Helmholtz-Zentrum für Polar und Meeresforschung; AlemaniaFil: Chiappero, Marina Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Fisiología. Cátedra de Genética de Poblaciones y Evolución; Argentin

Population genetic structure and demographic history of the scallop Argopecten purpuratus from Peru and Northern Chile: implications for management and conservation of natural beds

The scallop Argopecten purpuratus is a heavily exploited resource along the coasts of Peru and north-central Chile, especially after El Niño events, when the species undergoes high increases in abundance. Little is known about its genetic structure or demographic history, two important factors to ensure sustainable exploitation. We sequenced the cytochrome oxidase I and cytochrome b genes of 116 individuals from six localities (between 05°44′S 80°53′W and 23°31′S 70°33′W). We found high levels of genetic diversity in the analyzed populations. No geographical structuring was observed in the haplotype network, which consisted of a few central, widely distributed haplotypes, and many derived population-specific haplotypes separated by few mutations. This pattern suggests a recent population expansion and moderate to low current gene flow among populations. Mismatch analysis, neutrality tests, and a Bayesian skyline analysis confirmed the occurrence of a past event of population expansion approximately 5,000 years ago, which coincides with increasingly stronger and more frequent El Niño events

Population genetic structure and demographic history of the scallop Argopecten purpuratus from Peru and Northern Chile: Implications for management and conservation of natural beds

The scallop Argopecten purpuratus is a heavily exploited resource along the coasts of Peru and north-central Chile, especially after El Niño events, when the species undergoes high increases in abundance. Little is known about its genetic structure or demographic history, two important factors to ensure sustainable exploitation. We sequenced the cytochrome oxidase I and cytochrome b genes of 116 individuals from six localities (between 05°44′S 80°53′W and 23°31′S 70°33′W). We found high levels of genetic diversity in the analyzed populations. No geographical structuring was observed in the haplotype network, which consisted of a few central, widely distributed haplotypes, and many derived population-specific haplotypes separated by few mutations. This pattern suggests a recent population expansion and moderate to low current gene flow among populations. Mismatch analysis, neutrality tests, and a Bayesian skyline analysis confirmed the occurrence of a past event of population expansion approximately 5,000 years ago, which coincides with increasingly stronger and more frequent El Niño events.Fil: Acosta Jofré, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Sahade, Ricardo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Mendo, Jaime. Universidad Nacional Agraria La Molina ; PerúFil: González Ittig, Raúl Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Laudien, Jürgen. Alfred-Wegener-Institut. Helmholtz-Zentrum für Polar und Meeresforschung; AlemaniaFil: Chiappero, Marina Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin