| 1. |
- Ezzedine, Jade A., et al.
(författare)
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Adaptive traits of cysts of the snow alga Sanguina nivaloides unveiled by 3D subcellular imaging
- 2023
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Ingår i: Nature Communications. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Sanguina nivaloides is the main alga forming red snowfields in high mountains and Polar Regions. It is non-cultivable. Analysis of environmental samples by X-ray tomography, focused-ion-beam scanning-electron-microscopy, physicochemical and physiological characterization reveal adaptive traits accounting for algal capacity to reside in snow. Cysts populate liquid water at the periphery of ice, are photosynthetically active, can survive for months, and are sensitive to freezing. They harbor a wrinkled plasma membrane expanding the interface with environment. Ionomic analysis supports a cell efflux of K+, and assimilation of phosphorus. Glycerolipidomic analysis confirms a phosphate limitation. The chloroplast contains thylakoids oriented in all directions, fixes carbon in a central pyrenoid and produces starch in peripheral protuberances. Analysis of cells kept in the dark shows that starch is a short-term carbon storage. The biogenesis of cytosolic droplets shows that they are loaded with triacylglycerol and carotenoids for long-term carbon storage and protection against oxidative stress.
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| 2. |
- Sánchez-Guillén, Rosa A., et al.
(författare)
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The evolutionary history of colour polymorphism in Ischnura damselflies
- 2018
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Ingår i: Journal of evolutionary biology. - 1010-061X.
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Tidskriftsartikel (refereegranskat)abstract
- A major challenge in evolutionary biology consists of understanding how genetic and phenotypic variation is created and maintained. In this study, we investigated the origin(s) and evolutionary patterns of the female-limited colour polymorphism in ischnuran damselflies. These consist of the presence of one to three colour morphs: one androchrome morph with a coloration that is similar to the male and two gynochrome morphs (infuscans and aurantiaca) with female-specific coloration. We (i) documented the colour and mating system of 44 of the 75 taxa within the genus Ischnura, (ii) reconstructed the evolutionary history of colour and mating system to identify the ancestral state, (iii) evaluated the stability of the colour morph status over time and (iv) tested for a correlation between colour and mating system. We found that the ancestral female colour of Ischnura was monomorphic and aurantiaca and that colour morph status changed over time, characterized by many gains and losses across the species tree. Our results further showed that colour polymorphism is significantly more frequent among polyandric species, whereas monandric species tend to be monomorphic. Research on some Ischnura species has shown that colour morphs have evolved to reduce male mating harassment, and our finding that the same phenotypic morphs have evolved multiple times (convergent evolution) suggests that several species in this genus might be experiencing similar selective pressures.
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