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Conjugated polyelectrolytes (CPEs), materials that are defined by a π$\pi$‐conjugated backbone and charged ionic functional groups, are frequently prepared through direct polymerization of charged monomer species in aqueous media. This route is, however, often accompanied by labor‐intensive work‐up procedures, low yields, and ultimately results in materials that are difficult to characterize. To overcome these inconveniences, in this work protection chemistry is applied on sulfonate‐functionalized fluorene monomers that are polymerized under standard Suzuki polycondensation conditions to obtain protected donor–acceptor copolymers. Treatment of the organo‐soluble precursors under nucleophilic conditions resulted in quantitative removal of the protecting groups, thereby exposing the strong anionic functionalities. Unlike in other studies, the conjugated backbones remained unharmed during this process: the photophysical properties of the CPEs are identical to their hydrophobic precursors. [ABSTRACT FROM AUTHOR]

Social stress can increase reactive oxygen species and derail antioxidant function in the brain, which may contribute to the onset and progression of mental health disorders. In hierarchical species, repeated social defeat can raise oxidative stress in the brain. However, how oxidative balance in the brain is regulated across different levels in a social hierarchy is unknown. Here, we study the effect of social status on patterns of oxidative stress across several brain divisions in a highly social cichlid fish, Astatotilapia burtoni. In this species, dominant males are territorial, brightly colored, and reproductively active while subordinate males are not. We measured several markers of oxidative stress in macrodissected brain divisions in dominant and subordinate males. We found that dominant individuals had lower oxidative DNA damage (8-OhdG) in the midbrain while also having increased total antioxidant capacity in the midbrain and hypothalamus. However, in dominant males, oxidative DNA damage tended to be higher in the hypothalamus while total glutathione levels were lower in the telencephalon compared to subordinate males. Finally, we found that indicators of reproductive activity (gonadosomatic index and social behavior) were co-regulated with antioxidant function or oxidative damage in the telencephalon. Combined, our results suggest that social status and activation of the reproductive system regulate oxidative balance in the brain in a highly brain division specific manner. [ABSTRACT FROM AUTHOR]

The expression of sexually selected traits, such as ornaments or body coloration, is often influenced by environmental conditions. While such phenotypic plasticity is often thought to precede evolutionary change, plasticity itself can also be a target of selection. However, the selective forces supporting the evolution and persistence of plasticity in sexual traits are often unclear. Using the cichlid fish Astatotilapia burtoni, we show that variation in the level of mate competition may promote plasticity in body coloration. In this species, males can change between yellow and blue colour. We found that experimentally increased competition over mating territories led to a higher proportion of males expressing the yellow phenotype. The expression of yellow coloration was found to be beneficial because yellow males won more staged dyadic contests and exhibited a lower level of oxidative stress than blue males. However, females were more likely to spawn with blue males in mate choice experiments, suggesting that expression of blue coloration is sexually more attractive. The ability to adjust colour phenotype according to the local competitive environment could therefore promote the persistence of plasticity in coloration. [ABSTRACT FROM AUTHOR]