Alelopatia é definida pela Sociedade Internacional de Alelopatia como a ciência que estuda qualquer processo envolvendo essencialmente os metabólitos secundários produzidos pelas plantas, algas, bactérias e fungos que influenciam o crescimento e desenvolvimento de sistemas agrícolas e biológicos, incluindo efeitos positivos e negativos. Entretanto, diversas dúvidas são evidenciadas em novos pesquisadores da área, como o surgimento e evolução dessa ciência. Dessa forma, reunimos de forma didática algumas informações importantes acerca da alelopatia, as quais estão distribuídas em (1) Alelopatia: Histórico e Definições, (2) Modo de Ação dos Aleloquímicos e (3) Natureza Química dos Aleloquímicos, a fim de nortear os novos pesquisadores e possibilitar a utilização destas informações em sala de aula como recurso teórico.

No abstract

Tuberculosis (TB) is a chronic and serious infectious disease caused by Mycobacterium tuberculosis that mainly affects the lungs, but it is also capable of infecting other organs/tissues in the body, which triggers extra-pulmonary TB. In recent years, there has been an increase in the number of re-emerging TB cases due to resistance of M. tuberculosis to the antibiotics used to treat this disease. On top of that, there is the emergence of multidrug-resistant M. tuberculosis for which many of the antibiotics previously used have no effect. For these reasons, it was aimed to investigate the resistance mechanisms of M. tuberculosis in the TB pathogenicity in humans, considering this as a factor associated with re-emergence cases of this disease. Thus, it was carried out an integrative literature review based on articles selected in the SciElo, PubMed and Science Direct databases by using terminology in Portuguese and in English. Studies highlighted that the resistance mechanisms of M. tuberculosis consist of the emergence of mutations in target-genes naturally selected over time, the presence of efflux pumps and some lipid substances in the bacterial cell wall that provide impermeability to the antibiotics with cytoplasmic activity. Furthermore, the inappropriate use of antibiotics during the antibiotic-therapy period causes the emergence of other types of resistance. Therefore, special attention must be given to the correct use of antibiotics during the TB treatment, as well as the development of new effective drugs against multidrug-resistant bacteria strains.

No abstract

Paullinia cupana (Kunth), popularly known as guarana, is a plant species from the Amazon Region of Brazil that stands out for being one of the most promising herbal medicines of the Brazilian flora since it has relevant biological properties. However, studies are still needed to use this species as a direct approach to evaluate aspects related to behavior and oxidative stress in invertebrate model animals. In this context, we aimed to evaluate the stimulant and the antioxidant effects of P. cupana in lobster cockroach Nauphoeta cinerea. For that, cockroaches were exposed to a diet separately supplemented by the decoction of P. cupana powder decoction at increasing concentrations of 1, 25, 50 and 100 mg/g for 42 days. Behavioral and biochemical assays were performed, respectively, to assess the locomotor/exploratory performance and oxidative stress marker levels of the cockroaches. They exhibited an outstanding increase in the locomotion performance and in the cell viability content, as well as in the protein and non-protein thiol levels. Moreover, there was a decrease in lipid peroxidation levels and in free Fe2+ ion contents. Together, our results demonstrate the stimulant and the antioxidant capacity of P. cupana by acting positively in behavioral patterns and by regulating oxidative stress markers in lobster cockroach N cinerea. These findings encourage further laboratory analyzes in order to better enlighten the specific mechanisms of action attributed to guarana.