1,721,258 research outputs found
Bulk gut content and mantle glycogen content of antarctic ascidians from different stations inside Potter Cove
No full textThe gut content (dry mass and organic matter fraction) of three antarctic ascidians (Corella antarctica, Cnemidocarpa verrucosa, and Molgula pedunculata) under different sedimentation regimes were estimated together with mantel glycogen content. Samples were taken by scuba diving at 20 m depth at three different stations inside Potter Cove (South Shetlands, Antarctica): Inner Station (62º13'23.6''S; 58º38'41''W), Middle Station (62º13'54''S; 58º40'06''W), and Outer Station (62º14'10''S; 58º42'48''W) during austral February 2011.Fil: 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: Alurralde, Roque Gastón. 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: Abele, Doris. Alfred Wegener Institute; AlemaniaFil: 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; Argentin
A molecular perspective on the invasibility of the southern ocean benthos: the impact of hypoxia and temperature on gene expression in South American and Antarctic Aequiyoldia bivalves.
Get PDFWhen an organism makes a long-distance transition to a new habitat, the associated environmental change is often marked and requires physiological plasticity of larvae, juveniles, or other migrant stages. Exposing shallow-water marine bivalves (Aequiyoldia cf. eightsii) from southern South America (SSA) and the West Antarctic Peninsula (WAP) to changes in temperature and oxygen availability, we investigated changes in gene expression in a simulated colonization experiment of the shores of a new continent after crossing of the Drake Passage, and in a warming scenario in the WAP. Bivalves from SSA were cooled from 7°C (in situ) to 4°C and 2°C (future warmed WAP conditions), WAP bivalves were warmed from 1.5°C (current summer in situ) to 4°C (warmed WAP),
gene expression patterns in response to thermal stress by itself and in combination with hypoxia were measured after 10 days. Our results confirm that molecular plasticity may play a vital role for local adaptation. Hypoxia had a greater effect on the transcriptome than temperature alone. The effect was further amplified when hypoxia and temperature acted as combined stressors. The WAP bivalves showed a remarkable ability to cope with short-term exposure to hypoxia by switching to a metabolic rate depression strategy and activating the alternative oxidation
pathway, whilst the SSA population showed no comparable response. In SSA, the high prevalence of apoptosis-related differentially expressed genes especially under combined higher temperatures and hypoxia indicated that the SSA Aequiyoldia are operating near their physiological limits already. While the effect of temperature per se may not represent the single most effective barrier to Antarctic colonization by South American bivalves, the current distribution patterns as well as their resilience to future conditions can be better understood by looking at the synergistic effects of temperature in conjunction with short-term exposure to hypoxia.ANII: POS_EXT_2015_12279
Mitochondrial heteroplasmy and PCR amplification bias lead to wrong species delimitation with high confidence in the South American and Antarctic marine bivalve Aequiyoldia eightsii species complex
Get PDFThe species delimitation of the marine bivalve species complex Aequiyoldia eightsii in South America and Antarctica is complicated by mitochondrial heteroplasmy and amplification bias in molecular barcoding. In this study, we compare different data sources (mitochondrial cytochrome c oxidase subunit I (COI) sequences; nuclear and mitochondrial SNPs). Whilst all the data suggest that populations on either side of the Drake Passage belong to different species, the picture is less clear within Antarctic populations, which harbor three distinct mitochondrial lineages (p-dist ≈ 6%) that coexist in populations and in a subset of individuals with heteroplasmy. Standard barcoding procedures lead to amplification bias favoring either haplotype unpredictably and thus overestimate the species richness with high confidence. However, nuclear SNPs show no differentiation akin to the trans-Drake comparison, suggesting that the Antarctic populations represent a single species. Their distinct haplotypes likely evolved during periods of temporary allopatry, whereas recombination eroded similar differentiation patterns in the nuclear genome after secondary contact. Our study highlights the importance of using multiple data sources and careful quality control measures to avoid bias and increase the accuracy of molecular species delimitation. We recommend an active search for mitochondrial heteroplasmy and haplotype-specific primers for amplification in DNA-barcoding studies.ANII: POS_EXT_2015_12279
Physiological measurements in the gill tissue of intertidal Antarctic limpets (Nacella concinna) from Potter Cove, King George Island, West Antarctic Peninsula in 2007
No full textPhysiological measurements in the gill tissue of intertidal Antarctic limpets (Nacella concinna) from Potter Cove, King George Island, West Antarctic Peninsula in 200
Shell properties of subtidal Antarctic limpets (Nacella concinna), collected in Potter Cove, King George Island, West Antarctic Peninsula in 2007
No full textShell properties of subtidal Antarctic limpets (Nacella concinna), collected in Potter Cove, King George Island, West Antarctic Peninsula in 200
Shell properties of intertidal Antarctic limpets (Nacella concinna), collected in Potter Cove, King George Island, West Antarctic Peninsula in 2007
No full textShell properties of intertidal Antarctic limpets (Nacella concinna), collected in Potter Cove, King George Island, West Antarctic Peninsula in 200
Physiological measurements in the foot tissue of subtidal Antarctic limpets (Nacella concinna) from Potter Cove, King George Island, West Antarctic Peninsula in 2005
No full textPhysiological measurements in the foot tissue of subtidal Antarctic limpets (Nacella concinna) from Potter Cove, King George Island, West Antarctic Peninsula in 200
Physiological measurements in the foot tissue of intertidal Antarctic limpets (Nacella concinna) from Potter Cove, King George Island, West Antarctic Peninsula in 2005
No full textPhysiological measurements in the foot tissue of intertidal Antarctic limpets (Nacella concinna) from Potter Cove, King George Island, West Antarctic Peninsula in 200
Physiological measurements in the gill tissue of subtidal Antarctic limpets (Nacella concinna) from Potter Cove, King George Island, West Antarctic Peninsula in 2007
No full textPhysiological measurements in the gill tissue of subtidal Antarctic limpets (Nacella concinna) from Potter Cove, King George Island, West Antarctic Peninsula in 200
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