Simon Lamarre

To promote the rational use of Inonotus obliquus (chaga) from Eastern Canada, a mushroom consumed in infusion as a health drink, the extraction of its constituents was investigated. The extraction was carried out with water or ethanol at room temperature or by heating as well as following exposure to ultrasound. The extracts of the four seasons obtained with the four extraction methods were compared for their contents in carbon, nitrogen (N), sulfur (S), potassium (K), betulin, betulinic acid, potassium, flavonoids, and polyphenols. The antiradical effect as well as the photoprotective effects of all extracts were also investigated. The results show that there is no difference between the quantities extracted from the extracts of the 4 seasons. The results show a significant difference between the mass of the extracts obtained with water and ethanol. Betulinic acid was found to be more abundant in the extracts obtained with water while betulin was more abundant in the extracts obtained with ethanol. The mushroom and the extracts had high C contents, but low N and S contents, typical of protein-poor and carbohydrate-rich materials. Extracts were particularly rich in potassium, five times more than bananas. Heating favors the extraction of polyphenols and flavonoids. The aqueous extracts of chaga harvested in winter had the highest antiradical capacity. With a Sun Protection Factor (SPF) higher than 30 in the UVB wavelength, chaga extracts might be used as sunscreen. Extracts obtained with water had the highest SPF in general. The analysis of this mushroom further highlights this local product that deserves more attention for its potential benefits as a functional food/nutraceutical product. In addition to its nutritional values, this mushroom can also be used for its cosmetic qualities as it can be used as a sunscreen.

Understanding the factors affecting the capacity of ectothermic fishes to cope with warming temperature is critical given predicted climate change scenarios. We know that a fish's social environment introduces plasticity in how it responds to high temperature. However, the magnitude of this plasticity and the mechanisms underlying socially modulated thermal responses are unknown. Using the amphibious hermaphroditic mangrove rivulus fish Kryptolebias marmoratus as a model, we tested three hypotheses: (1) social stimulation affects physiological and behavioural thermal responses of isogenic lineages of fish; (2) social experience and acute social stimulation result in distinct physiological and behavioural responses; and (3) a desensitization of thermal receptors is responsible for socially modulated thermal responses. To test the first two hypotheses, we measured the temperature at which fish emerged from the water (i.e. pejus temperature) upon acute warming with socially naive isolated fish and with fish that were raised alone and then given a short social experience prior to exposure to increasing temperature (i.e. socially experienced fish). Our results did not support our first hypothesis as fish socially stimulated by mirrors during warming (i.e. acute social stimulation) emerged at similar temperatures to isolated fish. However, in support of our second hypothesis, a short period of prior social experience resulted in fish emerging at a higher temperature than socially naive fish suggesting an increase in pejus temperature with social experience. To test our third hypothesis, we exposed fish that had been allowed a brief social interaction and naive fish to capsaicin, an agonist of TRPV1 thermal receptors. Socially experienced fish emerged at significantly higher capsaicin concentrations than socially naive fish suggesting a desensitization of their TRPV1 thermal receptors. Collectively, our data indicate that past and present social experiences impact the behavioural response of fish to high temperature. We also provide novel data suggesting that brief periods of social experience affect the capacity of fish to perceive warm temperature.