O hormônio insulina como um modelo para ensinar a estrutura tridimensional das proteínas

Proteins are the most ubiquitous macromolecules found in the living cells and have innumerous physiological functions. Therefore, it is fundamental to build a solid knowledge about the proteins three dimensional structure to better understand the living state. The hierarchical structure of proteins is usually studied in the undergraduate discipline of Biochemistry.  Here we described pedagogical interventions designed to increase the preservice teacher chemistry students’ knowledge about protein structure.  The activities were made using alternative and cheap materials to encourage the application of these simple methodologies by the future teachers in the secondary school.  From the primary structure of insulin chains, students had to construct a three-dimensional structure of insulin. After the activities, the students highlighted an improvement of their previous knowledge about proteins structure. The construction of a tridimensional model together with other activities seems to be an efficient way to promote the learning about the structure of proteins to undergraduate students. The methodology used was inexpensiveness and simple and it can be used both in the university and in the high-school.Proteins are the most ubiquitous macromolecules found in the living cells and have innumerous physiological functions. Therefore, it is fundamental to build a solid knowledge about the proteins three dimensional structure to better understand the living state. The hierarchical structure of proteins is usually studied in the undergraduate discipline of Biochemistry. Here we described pedagogical interventions designed to increase the preservice teacher chemistry students’ knowledge about protein structure. The activities were made using alternative and cheap materials to encourage the application of these simple methodologies by the future teachers in the secondary school. From the primary structure of insulin chains, students had to construct a three-dimensional structure of insulin. After the activities, the students highlighted an improvement of their previous knowledge about proteins structure. The construction of a tridimensional model together with other activities seems to be an efficient way to promote the learning about the structure of proteins to undergraduate students. The methodology used was inexpensiveness and simple and it can be used both in the university and in the high-school.As proteínas são macromoléculas amplamente encontradas nas células e possuem inúmeras funções fisiológicas. Consequentemente, é de fundamental construir um conhecimento sólido sobre estrutura tridimensional das proteínas. As estruturas proteicas são geralmente estudadas durante a graduação na disciplina de Bioquímica. Neste trabalho descrevemos intervenções pedagógicas planejadas para aumentar o conhecimento de estudantes de Química licenciatura sobre a estrutura de proteínas. As atividades foram realizadas utilizando materiais baratos para encorajar a sua implementação no ensino médio pelos futuros professores. A partir da estrutura primária da insulina, os estudantes construíram a estrutura tridimensional desta proteína. Após as atividades, os estudantes destacaram uma melhora nos seus conhecimentos prévios sobre a estrutura das proteínas. A construção de um modelo tridimensional juntamente com outras atividades parece ser uma maneira eficiente de promover o aprendizado sobre a estrutura de proteínas aos estudantes de graduação. A metodologia utilizada foi simples e de baixo custo e pode ser utilizada tanto no nível universitário como no nível do ensino médio

Perception of undergraduate students of a Brazilian University about the Biochemistry course

Biochemistry is an essential science that deals with the chemical bases of life, being an important discipline for several areas. Thus, the objective of this work was to evaluate the opinion of students about the Biochemistry course. An instrument, involving questions about the discipline, the professors, the monitors, and a self-evaluation was applied to 231 students from 12 undergraduate courses, divided into 3 areas of knowledge: Natural, Health and Rural Sciences. The majority of the students answered that they consider Biochemistry an important discipline, but they presented a reasonable comprehension of the contents, probably by a lack of chemical skills. The students consider the credit hour of the discipline sufficient but badly used. They said that the Professor performance is reasonable to good, and miss a correlation between the class and the professional acting, especially in the Rural Science. This study showed that the Biochemistry classes need to be rethought for the areas of action of each course. In addition, the students' basic pre-knowledge should be improved

Effects of Selenium Supplementation in Patients with Mild Cognitive Impairment or Alzheimer’s Disease: A Systematic Review and Meta-Analysis

Elevated levels of oxidative stress could cause and aggravate Alzheimer’s disease (AD). Selenium (Se) is a trace element with antioxidant and anti-inflammatory activity with neuroprotective effects. To evaluate the effects of Se supplementation in patients with AD or mild cognitive impairment (MCI) through a systematic review and meta-analysis, data were searched and collected from four electronic databases, including clinical trial studies published until December 2020, following the PRISMA guidelines. Statistical analysis was performed by RevMan, and the risk of bias was assessed using the Rob 2 tool. A total of 1350 scientific papers were collected, and following evaluation 11 papers were included in the systematic review and 6 of these were used in the meta-analysis. Studies that evaluated only Se supplementation observed an improvement in Se levels, glutathione peroxidase (GPX) activity, and in some cognitive tests in MCI patients; similarly, improvement in Se levels and mini-mental score was also observed in AD patients. Regarding supplementation of Se plus other nutrients, improvement in cognitive tests was observed in both AD and MCI patients. Therefore, Se supplementation is a good alternative for patients with AD and MCI for improving Se levels and GPX activity. More detailed studies are required to further evaluate the effects of Se on the cognitive deficit and oxidative stress associated with AD and MCI

Assessment of Neurotoxic Effects of Oxycodone and Naloxone in SH-SY5Y Cell Line

Opioid drugs have analgesic properties used to treat chronic and post-surgical pain due to descending pain modulation. The use of opioids is often associated with adverse effects or clinical issues. This study aimed to evaluate the toxicity of opioids by exposing the neuroblastoma cell line (SH-SY5Y) to 0, 1, 10, and 100 µM oxycodone and naloxone for 24 h. Analyses were carried out to evaluate cell cytotoxicity, identification of cell death, DNA damage, superoxide dismutase (SOD), glutathione S-transferase (GST), and acetylcholinesterase (AChE) activities, in addition to molecular docking. Oxycodone and naloxone exposure did not alter the SH-SY5Y cell viability. The exposure to 100 µM oxycodone and naloxone significantly increased the cells’ DNA damage score compared to the control group. Naloxone exposure significantly inhibited AChE, GST, and SOD activities, while oxycodone did not alter these enzymes’ activities. Molecular docking showed that naloxone and oxycodone interact with different amino acids in the studied enzymes, which may explain the differences in enzymatic inhibition. Naloxone altered the antioxidant defenses of SH-SY5Y cells, which may have caused DNA damage 24 h after the exposure. On the other hand, more studies are necessary to explain how oxycodone causes DNA damage

Δ-Aminolevulinate dehydratase and glutathione peroxidase activity in Alzheimer's disease

Alzheimer’s disease (AD) is a neurodegenerative pathology that affects elderly people all over the world. Several studies have demonstrated that oxidative stress is an aggravating factor for AD development and progression. Therefore, this study aimed to evaluate the activity of two oxidative stress markers, glutathione peroxidase (GPx) and δ -aminolevulinate dehydratase ( δ -ALA-D), as well as correlate them with blood metal levels and AD progression. For this purpose, 88 elderly individuals were divided in two groups: AD group (34 patients diagnosed with AD) and control group (34 subjects paired by age with the AD group). The Mini-Mental State Examination and the Clinical Dementia Rating (CDR ) were used as tools to classify the AD progression. GPx and δ -ALA-D activities were measured in all subjects through blood tests. Both enzymes’ activities were decreased in AD patients when compared to the age-matched control group, regardless of the CDR. Moreover, GPx activity was positively correlated with selenium levels in the blood; and the δ -ALA-D activity was negatively correlated with blood cop- per levels. Taken together, our results indicated that, for the first time, blood δ -ALA-D activity was significantly inhibited in AD patients. While literature reports conflicting data regarding GPx activity in AD patients, the δ - ALA-D activity seems to be a more consistent tool to be applied as an earlier AD marker