3 research outputs found

    Heat Attenuation and Nutrient Delivery by Localized Upwelling Avoided Coral Bleaching Mortality in Northern Galapagos During 2015/2016 ENSO

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    Despite a very strong El Niño Southern Oscillation in 2015/2016, no coral mortality associated with bleaching was observed at the northern Galapagos (Ecuador) Islands of Darwin and Wolf. From March 2016 to March 2018, coral cover and health as well as water chemistry (NO3− and PO43−) and temperature were recorded. A marked heat anomaly reached 30 °C at Wolf in February 2016, but peak temperatures were attenuated after 2 d by a 4 °C drop. Temperature patterns at three depths (10, 15, and 20 m) and a subsequent and persistent phytoplankton bloom suggest topographically driven upwelling as the source of colder water and dissolved inorganic nutrients—both of which helped corals endure the heating episode. Consequently, no mortality and only partial bleaching were recorded in March 2016. Partially bleached corals contained numerous healthy zooxanthellae in deeper tissue layers. A continuous temperature record from 2012 to 2014 suggests that such upwelling events are common, inducing temperature fluctuations of up to 6 °C within 24 h during the observation period. Events at Wolf in 2016 suggest local upwelling reduced coral stress by relieving heat and by delivering nutrients required by corals to retain their regular temperature tolerance

    Smad-Runx interactions during chondrocyte maturation

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    BACKGROUND: Intracellular signaling triggered by bone morphogenetic proteins (BMPs) results in activated Smad complexes that regulate transcription of BMP-responsive genes. However, the low specificity of Smad binding to regulatory sequences implies that additional tissue-specific transcription factors are also needed. Runx2 (Cbfal) is a transcription factor required for bone formation. We have examined the role of Smads and Runx2 in BMP induction of type X collagen, which is a marker of chondrocyte hypertrophy leading to endochondral bone formation. METHODS: Pre-hypertrophic chondrocytes from the cephalic portion of the chick embryo sternum were placed in culture in the presence or absence of rhBMP-2. Cultures were transiently transfected with DNA containing the BMP-responsive type X collagen promoter upstream of the luciferase gene. The cultures were also transfected with plasmids, causing over-expression of Smads or Runx2, or both. After 24-48 hours, cell extracts were examined for levels of luciferase expression. RESULTS: In the presence of BMP-2, chondrocytes over-expressing BMP-activated Smadl or Smad5 showed significant enhancement of luciferase production compared with that seen with BMP alone. This enhancement was not observed with over-expression of Smad2, a transforming growth factor beta (TGF-beta)-activated Smad. Overexpression of Runx2 in BMP-treated cultures increased transcriptional activity to levels similar to those seen with Smads 1 or 5. When chondrocytes were simultaneously transfected with both Runx2 and Smad 1 or 5, promoter activity was further increased, indicating that BMP-stimulated Smad activity can be augmented by increasing the levels of Runx2. CONCLUSIONS: These results implicate the skeletal tissue transcription factor Runx2 in regulation of chondrocyte hypertrophy and suggest that maximal transcription of the type X collagen gene in pre-hypertrophic chondrocytes involves interaction of BMP-stimulated Smads with Runx2. Clinical Relevance: Many skeletal abnormalities are associated with impaired regulation of chondrocyte hypertrophy in growth plates. These studies demonstrate that both BMP-activated Smads and Runx2 levels can modulate chondrocyte transition to hypertrophy

    Interaction Gardens and Butterfly Catalogues: a Joint Strategy to Promote Capacity Development in Protected Areas and Reduce the Extinction of Experience in Cities

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    More than half of the world’s population live in cities. Increasing numbers of generations are now born and raised in urban landscapes with decreasing opportunities towards interacting with natural environments. This extinction of experience leads to environmental apathy and lack of bioliteracy, which is a central aspect to be tackled in conservation strategies. At the same time, people who live near or at non-urban settings are closer to natural habitats but do not have similar access to concepts of environmentalism and may lack incentives to lean towards nature conservation, instead of its exploitation or even illegal activities. We here propose that interaction gardens, that is, gardens with multiple trophic levels (primary producers, herbivores, predators, and parasitoids), can tackle these issues, especially if planned with incentives, such as butterfly catalogues, aimed as a common goal of the garden community. It can also bring benefits to human health and well-being, increase the survival chances of local biodiversity, and strengthen the front line of conservation by promoting income strategies to people who live near protected areas. Our specific aims are to 1) share a case study of capacity development at the Intervales State Park in the Atlantic Forest, Southeast Brazil; 2) present the butterfly catalogue of this protected area; 3) present guidelines for interaction gardens at both urban and non-urban settings; and 4) discuss alternative perspectives about Neotropical conservation. We provide a translated version of the text in Portuguese to encourage students, educators, NGOs and local communities of other protected areas to venture in our proposed joint strategy of interaction gardens with butterfly catalogues
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