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Influencia diferencial de la expresión de Slc7a11 y la condición corporal sobre la pigmentación producida por feomelanina en dos poblaciones de trepador azul Sitta europea con diferente riesgo de depredación

The expression of the gene Slc7a11 promotes the antioxidant capacity of cells by providing them with cysteine that can be used for the synthesis of glutathione (GSH), the most important intracellular antioxidant. In melanocytes, intracellular cysteine can also enter melanosomes and get incorporated in the pigment pheomelanin synthesis pathway, thus decreasing cysteine availability for GSH synthesis and potentially creating chronic oxidative stress. Therefore, this study hypothesized that a mechanism limiting the use of intramelanocytic cysteine for pheomelanin synthesis in environmental conditions generating oxidative stress may be physiologically advantageous and favored by natural selection. Evidence we searched of such a mechanism by comparing the influence of melanocytic Slc7a11 expression on pheomelanin?based pigmentation in developing Eurasian nuthatch Sitta europaea nestlings from two populations differing in predation risk, a natural source of oxidative stress. Pheomelanin synthesis and pigmentation tended to increase with Slc7a11 expression in the low?risk population as expected from the activity of this gene, but decreased with Slc7a11 expression in the high?risk population. The same was not observed in the expression of five other genes influencing pheomelanin synthesis without affecting cysteine availability in melanocytes. The influence of body condition on the intensity of pheomelanin?based pigmentation also differed between populations, being positive in the low?risk population and negative in the high?risk population. The resulting pigmentation of birds was more intense in the high?risk population. These findings suggest that birds perceiving high predation risk may limit the use of cysteine for pheomelanin synthesis, which becomes independent of Slc7a11 expression. Some birds may have thus evolved the ability to adjust their pigmentation phenotype to environmental stress. informacion[at]ebd.csic.es: Galván & Sanz (2020) Differential influence of Slc7a11 expression and body condition on pheomelanin-based pigmentation in two Eurasian nuthatch Sitta europaea populations with different predation risk. J Avian Biol DOI 10.1111/jav.02275


https://onlinelibrary.wiley.com/doi/10.1111/jav.02275
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New "Silk Road" brings challenges and opportunities for biodiversity conservation

New "Silk Road" brings challenges and opportunities for biodiversity conservation

China is establishing an infrastructure and service network to connect the country, by land and sea, to different parts of Asia, Africa and Europe. This Chinese project would then represent not only an investment to foster international trade but also an opportunity for sustainable development leadership. According to Chinese government, this new "Silk Road" counts on the participation of least 65 countries, involve about two-thirds of the world's population and boost one-third of the global economy. This "Belt and Road" initiative (BRI) promises to greatly influence the future of global trade and promote the economic development around the world. However, it may also promote permanent environmental degradation. The implementation of BRI implies massive rail and road infrastructure expansion, new ports construction in the Pacific and Indian Oceans, and the creation of oil and gas pipelines to Russia, Kazakhstan and Myanmar. BRI's economic development corridors coincide with high environmental value areas and can therefore have significant impacts on biodiversity. A recent report by the World Wildlife Fund (WWF) shows that these corridors overlap with 1739 Key Biodiversity Areas (KBAs) and with the range of 265 threatened species, including 39 critically endangered. Abrupt changes in ecosystem quality and functionality due to pollution, the spread of invasive species, restrictions of animal movement, habitat loss and increased wildlife mortality, are at stake. In addition, raw materials and fossil fuels use, and increased oil and gas reserves exploitation constitute a scenario of an increasing dependency on fossil-fuel and high greenhouse gas emissions. All BRI-related projects should undergo Strategic Environmental and Social Assessments which provide, at an early stage of decision-making, holistic information on the costs and benefits of development plans, including those reflecting the impacts on biodiversity and human populations. The Belt and Road Initiative could be an opportunity for China to take a leading role in moving global development towards sustainability by requiring its overseas partners at least the same environmental quality China aspires for within its territory. informacion[at]ebd.csic.es: Ascensão et al (2018): Environmental challenges for the Belt and Road Initiative. Nature Sustainability Doi: 10.1038/s41893-018-0059-3


https://www.nature.com/articles/s41893-018-0059-3