Genetic characterization of species using phylogeographic approaches represents a basic reference to understand their evolutionary history as well as to identify conservation priorities to protect areas of particular ...Genetic characterization of species using phylogeographic approaches represents a basic reference to understand their evolutionary history as well as to identify conservation priorities to protect areas of particular interest regarding evolutionary potential.Even in well-studied regions such information is lacking for the majority of species,including many endemic species with reduced distribution ranges.We investigate the phylogeographic pattern of the Iberian frog Rana iberica,an endemic amphibian restricted to Central and North-Western Iberian Peninsula.Using mitochondrial sequences,we reconstruct the phylogeographic history of the species to test the effect of Quaternary climate changes on the evolutionary diversification of lineages,that is,the differentiation of mitochondrial lineages and the formation of genetic diversity melting pots,and integrate phylogeographic evidence for future conservation planning.Our results indicate the existence of 3 main mitochondrial lineages differentiated during the Upper Pleistocene.Both historical demographic analyses and climatic niche modeling show a strong effect of glacial climate changes,suggesting recurrent range contractions and expansions.Under such circumstances,differentiation took place most likely by isolation in allopatric interglacial refugia.Secondary lineage admixture in northern Portugal generated a broad mixed zone with highest nucleotide diversity.Given its particular evolutionary potential,its reduced distribution and eventual threats under current climate change scenario,conservation priorities should focus on the isolated lineage from Sierra de Guadalupe.展开更多
A central composite rotatable design and response surface methodology were used in order to investigate the individual and combined effects of the ethanol-to-oil ratio, H2SO4 concentration, temperature and time of rea...A central composite rotatable design and response surface methodology were used in order to investigate the individual and combined effects of the ethanol-to-oil ratio, H2SO4 concentration, temperature and time of reaction on the reduction of free fatty acid （FFA） in jatropha oil. A quadratic polynomial model relating the reaction variables with FFA reduction was developed, presenting a good coefficient of determination （R2= 0.893）. For reducing FFA to less than 1%, the optimal combination was found to be 0.62 v.v^-1 ethanol-to-oil ratio （14.9 v.v^-1 ethanol-to-FFA ratio）, 1.7% v.vI H2SO4 concentration, and 79 rain reaction time at a reaction temperature of 54℃. These results are of great relevance to maximize methyl esters formation by transesterification using an alkaline catalyst.展开更多
文摘Genetic characterization of species using phylogeographic approaches represents a basic reference to understand their evolutionary history as well as to identify conservation priorities to protect areas of particular interest regarding evolutionary potential.Even in well-studied regions such information is lacking for the majority of species,including many endemic species with reduced distribution ranges.We investigate the phylogeographic pattern of the Iberian frog Rana iberica,an endemic amphibian restricted to Central and North-Western Iberian Peninsula.Using mitochondrial sequences,we reconstruct the phylogeographic history of the species to test the effect of Quaternary climate changes on the evolutionary diversification of lineages,that is,the differentiation of mitochondrial lineages and the formation of genetic diversity melting pots,and integrate phylogeographic evidence for future conservation planning.Our results indicate the existence of 3 main mitochondrial lineages differentiated during the Upper Pleistocene.Both historical demographic analyses and climatic niche modeling show a strong effect of glacial climate changes,suggesting recurrent range contractions and expansions.Under such circumstances,differentiation took place most likely by isolation in allopatric interglacial refugia.Secondary lineage admixture in northern Portugal generated a broad mixed zone with highest nucleotide diversity.Given its particular evolutionary potential,its reduced distribution and eventual threats under current climate change scenario,conservation priorities should focus on the isolated lineage from Sierra de Guadalupe.
文摘A central composite rotatable design and response surface methodology were used in order to investigate the individual and combined effects of the ethanol-to-oil ratio, H2SO4 concentration, temperature and time of reaction on the reduction of free fatty acid （FFA） in jatropha oil. A quadratic polynomial model relating the reaction variables with FFA reduction was developed, presenting a good coefficient of determination （R2= 0.893）. For reducing FFA to less than 1%, the optimal combination was found to be 0.62 v.v^-1 ethanol-to-oil ratio （14.9 v.v^-1 ethanol-to-FFA ratio）, 1.7% v.vI H2SO4 concentration, and 79 rain reaction time at a reaction temperature of 54℃. These results are of great relevance to maximize methyl esters formation by transesterification using an alkaline catalyst.
