RESUMEN
Dairy product consumption is a common habit in Brazil. These products present a good matrix for probiotic incorporation. Thus, in this study the feasibility of producing a probiotic "requeijão cremoso" incorporated with Bacillus coagulans GBI-30 6086 in three different steps and its metabolic effect in an animal model for 2 weeks has been evaluated. Wistar adult health rats were randomized into one to five groups (n = 8 for each group): Control (C); "requeijão cremoso" without probiotic (RC); probiotic inoculated in the milk before pasteurization at 65°C/30 min (RPP); "requeijão cremoso" inoculated before the fusion step and consequently exposed to 90°C/5 min (RPF); and "requeijão cremoso" inoculated after fusion step, i.e., once the product temperature reached 50°C (RPAF). At the end of treatment, analysis of molecular markers of proteins of stress and antioxidant system, HSP 25, 60, 70 and 90, SOD and catalase were performed in the animals' muscles by Western Blot technique. The HSP25, HSP90 and catalase levels of C, RPP, RPF, and RPAF were similar, indicating that the homeostasis remained unchanged. The incorporation of B. coagulans GBI-30 6086 in the "requeijão cremoso" was shown to be stable and the microorganism remained viable in all steps tested. The incorporation of the probiotic strain in the fusion stage facilitated the technological process, since it allowed a better homogenization of the product and did not affect the maintenance of the metabolic homeostasis of rats.
RESUMEN
The Keap1-Nrf2 system is an evolutionarily conserved defense mechanism against oxidative and xenobiotic stress. Its regulatory mechanisms, e.g., stress-sensing mechanism, proteasome-based regulation of Nrf2 activity and selection of target genes, have been elucidated mainly in mammals. In addition, emerging model animals, such as zebrafish, fruit fly and Caenorhabditis elegans, have been shown to have similar anti-stress systems to mammals, suggesting that analogous defense systems are widely conserved throughout the animal kingdom. Experimental evidence in lower animals provides important information beyond mere laboratory-confined utility, such as regarding how these systems transformed during evolution, which may help characterize the mammalian system in greater detail. Recent advances in genome projects of both model and non-model animals have provided a great deal of useful information toward this end. We herein review the research on Keap1-Nrf2 and its analogous systems in both mammals and lower model animals. In addition, by comparing the amino acid sequences of Nrf2 and Keap1 proteins from various species, we can deduce the evolutionary history of the anti-stress system. This combinatorial approach using both experimental and genetic data will suggest perspectives of approach for researchers studying the stress response.