The biological actions of growth hormone (GH) are pleiotropic, including growth promotion, energy mobilization, gonadal development, appetite, and social behavior. The regulatory network for GH is complex and includes many central and peripheral endocrine factors as well as that from the environment. It is known that GH transgenesis results in increased growth, food intake, and consequent metabolic rates in fishes. However, the manner in which GH transgenesis alters the energetic metabolism in fishes has not been well explored. In order to elucidate these consequences, we examined the effect of GH overexpression on appetite control mechanisms in a transgenic zebrafish (Danio rerio) model. To this, we analyzed feeding behavior and the expression of the main appetite-related genes in two different feeding periods (fed and fasting) in non-transgenic (NT) and transgenic (T) zebrafish as well as glycaemic parameters of them. Our initial results have shown that NT males and females present the same feeding behavior and expression of main appetite-controlling genes; therefore, the data of both sexes were properly grouped. Following grouped data analyses, we compared the same parameters in NT and T animals. Feeding behavior results have shown that T animals eat significantly more and faster than NT siblings. Gene expression results pointed out that gastrointestinal (GT) cholecystokinin has a substantial contribution to the communication between peripheral and central control of food intake. Brain genes expression analyses revealed that T animals have a down-regulation of two strong and opposite peptides related to food intake: the anorexigenic proopiomelanocortin (pomc) and the orexigenic neuropeptide Y (npy). The down-regulation of pomc in T when compared with NT is an expected result, since the decrease in an anorexigenic factor might keep the transgenic fish hungry. The down-regulation of npy seemed to be contradictory at first, but if we consider the GH's capacity to elevate blood glucose, and that NPY is able to respond to humoral factors like glucose, this down-regulation makes sense. In fact, our last experiment showed that transgenics presented elevated blood glucose levels, confirming that npy might responded to this humoral factor. In conclusion, we have shown that GT responds to feeding status without interference of transgenesis, whereas brain responds to GH transgenesis without any effect of treatment. It is clear that transgenic zebrafish eat more and faster, and it seems that it occurs due to pomc down-regulation, since npy might be under regulation of the humoral factor glucose.
Ocean warming is one of the greatest global threats to coral reef ecosystems; it leads to the disruption of the coral–dinoflagellate symbiosis (bleaching) and to nutrient starvation, because corals mostly rely on autotrophy (i.e., the supply of photosynthates from the dinoflagellate symbionts) for their energy requirements. Although coral bleaching has been well studied, the early warning signs of bleaching, as well as the capacity of corals to shift from autotrophy to heterotrophy, are still under investigation. In this study, we evaluated the bleaching occurrence of the scleractinian coral Mussismillia harttii and the hydrocoral Millepora alcicornis during a natural thermal stress event, under the 2015–2016 El Niño influence in three reef sites of the South Atlantic. We focused on the link between peroxynitrite (ONOO−) generation and coral bleaching, as ONOO− has been very poorly investigated in corals and never during a natural bleaching event. We also investigated the natural trophic plasticity of the two corals through the use of new lipid biomarkers. The results obtained first demonstrate that ONOO− is linked to the onset and intensity of bleaching in both scleractinian corals and hydrocorals. Indeed, ONOO− concentrations were correlated with bleaching intensity, with the highest levels preceding the highest bleaching intensity. The time lag between bleaching and ONOO− peak was, however, species-specific. In addition, we observed that elevated temperatures forced heterotrophy in scleractinian corals, as Mu. harttii presented high heterotrophic activity 15 to 30 days prior bleaching occurrence. On the contrary, a lower heterotrophic activity was monitored for the hydrocoral Mi. alicornis, which also experienced higher bleaching levels compared to Mu. hartii. Overall, we showed that the levels of ONOO− in coral tissue, combined to the heterotrophic capacity, are two good proxies explaining the intensity of coral bleaching.
Different ingredients and adjuncts have been used in the production of craft beer aiming to add new characteristics to the final product. In turn, the pecan nut has recognized antioxidant properties and, therefore, the extract of its shell was added in the beer production process with the main objective of increasing the beer antioxidant capacity. The all-grain method was used to produce the beverage and, on the packaging step, pecan nutshell extract was added at three different concentrations. The samples underwent antioxidant, physicochemical, and sensorial analysis. Data were submitted to analysis of variance (ANOVA). The use of pecan nutshell extract as an ingredient in beer processing has proved to be a viable alternative due to satisfactory results in sensory evaluation, with good acceptability of the consumers, maintaining physicochemical characteristics similar to the standard beer produced without the extract. However, the addition of the extract did not increase the antioxidant capacity in craft beer. Even though the antioxidant power of produced beer wasn´t increased in this experiment, still pecan nutshell could be a good resource of antioxidants to whom drink beer, and your low price in the market make it viable to beer industry.
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