Effect of neonatal melatonin administration on behavioral and brain electrophysiological and redox imbalance in rats.

Introduction: Melatonin (MLT) reportedly has beneficial effects in neurological disorders involving brain excitability (e.g., Epilepsy and Migraine) and behavioral patterns (e.g., Anxiety and Depression). This study was performed to investigate, in the developing rat brain, the effect of early-in-life administration of two different doses of exogenous MLT on behavioral (anxiety and memory) and electrophysiological (CSD analysis) aspects of brain function. Additionally, brain levels of malondialdehyde (MDA) and superoxide dismutase (SOD), both cellular indicators of redox balance status, were evaluated. We hypothesize that MLT differentially affects the behavioral and CSD parameters as a function of the MLT dose. Materials and methods: Male Wistar rats received, from the 7th to the 27th postnatal day (PND), on alternate days, vehicle solution, or 10 mg/kg/or 40 mg/kg MLT (MLT-10 and MLT-40 groups), or no treatment (intact group). To perform behavioral and cognition analysis, from PND30 to PND32, they were tested in the open field apparatus, first for anxiety (PND30) and then for object recognition memory tasks: spatial position recognition (PND31) and shape recognition (PND32). On PND34, they were tested in the elevated plus maze. From PND36 to 42, the excitability-related phenomenon known as cortical spreading depression (CSD) was recorded, and its features were analyzed. Results: Treatment with MLT did not change the animals' body weight or blood glucose levels. The MLT-10 treatment, but not the MLT-40 treatment, was associated with behaviors that suggest less anxiety and improved memory. MLT-10 and MLT-40 treatments, respectively, decelerated and accelerated CSD propagation (speed of 2.86 ± 0.14 mm/min and 3.96 ± 0.16 mm/min), compared with the control groups (3.3 ± 0.10 mm/min and 3.25 ± 0.11 mm/min, for the intact and vehicle groups, respectively; p < 0.01). Cerebral cortex levels of malondialdehyde and superoxide dismutase were, respectively, lower and higher in the MLT-10 group but not in the MLT40 group. Conclusion: Our findings suggest that MLT intraperitoneal administration during brain development may differentially act as an antioxidant agent when administered at a low dose but not at a high dose, according to behavioral, electrophysiological, and biochemical parameters.

The antioxidant defence of Dekkera bruxellensis against hydrogen peroxide and its relationship to nitrate metabolism.

AIMS: The yeast Dekkera bruxellensis is a Crabtree-positive yeast that tends towards the oxidative/respiratory metabolism in aerobiosis. However, it is more sensitive to H2O2 than Saccharomyces cerevisiae. In order to investigate this metabolic paradox, the present work aimed to uncover the biological defence mechanism used by this yeast to tolerate the presence of exogenous H2O2. METHODS AND RESULTS: Growth curves and spot tests were performed to establish the values of minimal inhibitory concentration and minimal biocidal concentration of H2O2 for different combinations of carbon and nitrogen sources. Cells in exponential growth phase in different culture conditions were used to measure superoxide and thiols [protein (PT) and non-PT], enzyme activities and gene expression. CONCLUSIONS: The combination of glutathione peroxidase (Gpx) and sulfhydryl-containing PT formed the preferred defence mechanism against H2O2, which was more efficiently active under respiratory metabolism. However, the action of this mechanism was suppressed when the cells were metabolizing nitrate (NO3). SIGNIFICANCE AND IMPACT OF STUDY: These results were relevant to figure out the fitness of D. bruxellensis to metabolize industrial substrates containing oxidant molecules, such as molasses and plant hydrolysates, in the presence of a cheaper nitrogen source such as NO3.

Influence of SARS-CoV-2 during pregnancy: a placental view.

Since the beginning of the current coronavirus outbreak (COVID-19), there has been great concern over a disease that has spread rapidly in several countries worldwide, with the result of several deaths, including deaths of pregnant women. Therefore, the aim of this study was to conduct a literature review on placental changes in infected pregnant women and/or asymptomatic carriers of COVID-19 during pregnancy, aiming at the possible vertical transmission. A systematic collection was carried out on the effects of that COVID-19 can cause directly and/or indirectly to pregnancy and the placenta in the following databases: Pubmed, Science Direct, Scielo, Lilacs, and Web of Science. For search, the following descriptors were used: placenta, pregnant woman, COVID-19, maternal-fetal. The results indicate transplacental transmission in some cases reviewed in many reports from this study. The presence of the virus was seen in the amniotic fluid, umbilical cord, and peripheral blood. Finally, pathological studies suggest that there are morphological changes related to infection in the placentas. We can conclude that, based on the researched material, there is little evidence of transplacental vertical viral transmission and its respective morphological changes related to viral infection in the placenta.