Mixed metal oxide nanoparticles inhibit growth of Mycobacterium tuberculosis into THP-1 cells

Objective/background: Humans have been in a constant battle with tuberculosis (TB). Currently, overuse of antibiotics has resulted in the spread of multidrug-resistant Mycobacterium tuberculosis (MDR), leading to antibiotic ineffectiveness at controlling the spread of TB infection in host cells and especially macrophages. Additionally, the Mycobacterium tuberculosis (Mtb) has developed methods to evade the immune system and survive. With the discovery of nanoparticle (NP)-based drugs, it is necessary to research their anti-mycobacterial properties and bactericidal mechanisms. In this study, we synthesized mixed metal oxide NPs and tested their ability to inhibit Mtb growth into macrophages and investigated the cytotoxic effects of NPs in THP-1 cells. Methods: Silver (Ag) NPs and zinc oxide (ZnO) NPs were synthesized by chemical reduction and chemical deposition in aqueous solution, and the diffraction light scattering, scanning electron microscopy, transmission electron microscopy, and ultraviolet–visible light-absorption spectra were used to identify NP properties. Ag and ZnO NPs were mixed together at a ratio of 8ZnO/2Ag and diluted into Löwenstein–Jensen medium followed by the addition of bacteria and incubation for 28 days at 37°C. The toxicity of NPs to THP-1 cells was assessed by MTT test, and macrophages were infected with Mtb for 4 h at 37°C under 5% CO2. Results: Nano-sized particles were estimated at ˜30–80nm, and the initial concentration of Ag NPs and ZnO NPs were estimated at ˜20 ppm and ˜60 ppm. The minimal inhibitory concentration ratio of 8ZnO/2Ag NPs against Mtb was detected at ˜1/32 of the initial concentration. Ag NPs in the range of concentrations exhibited no anti-Mtb effects, whereas ZnO NPs showed potent antibacterial activity at ˜1/128 of the initial concentration. ZnO NPs at all concentrations showed cytotoxic activity, whereas 100% of THP-1 cells remained viable in the presence of Ag NPs at ˜1/32 and ˜1/64 of the initial concentrations. However, at ratios of 8ZnO/2Ag, ˜39.94% of the cells at ˜1/16 of the initial concentration remained viable, with 100% of THP-1 cells at ˜1/32 of the initial concentration remaining viable. Conclusion: Although Ag NPs exhibited low cytotoxicity, they were unable to inhibit Mtb growth in vitro. ZnO NPs exhibited strong anti-Mtb activity and inhibited bacterial growth, but exhibited high cytotoxicity to human macrophage cells. By mixing Ag and ZnO NPs at a ratio of 8ZnO/2Ag, we acquired a mixture that exhibited potent antibacterial activity against Mtb and no cytotoxic effects on THP-1 cells, resulting in inhibition of both in vitro and ex vivo Mtb growth [Figure 1],[Figure 2],[Figure 3], [Table 1],[Table 2],[Table 3].{Figure 1}{Figure 2}{Figure 3} {Table 1}{Table 2}{Table 3

Aspectos da biologia reprodutiva de Jatropha curcas L Reproductive biology aspects of Jatropha curcas L

O conhecimento da estrutura floral e da biologia reprodutiva numa cultura é básico para que o melhorista desenvolva técnicas de castração e polinização adequadas. Objetivando obter dados de biologia reprodutiva de pinhão manso, inflorescências emasculadas, foram observadas sem isolamento (controle positivo) e isoladas com tecido "nylon" tipo voal para posterior realização dos tratamentos de geitonogamia e xenogamia após a antese. Os tratamentos consistiram de controle positivo (flores não isoladas), e a partir das flores isoladas foram obtidos os demais tratamentos: controle negativo (sem polinização); xenogamia (receberam pólen de outra planta); geitonogamia 1 (receberam pólen da mesma inflorescência); geitonogamia 2 (receberam pólen de outra inflorescência da mesma planta). Os resultados indicam que a espécie não apresenta problemas de autoincompatibilidade, sendo os índices de fecundação bastante elevados e indiferentes estatisticamente em todos os tratamentos, com valores acima de 80%, exceto para o controle negativo em que as inflorescências foram isoladas e não polinizadas, resultando em ausência de fecundação e de frutos. Esse último resultado mostra a importância da visitação de insetos para a obtenção de sucesso no processo reprodutivo da espécie. As flores masculinas, doadoras de pólen, abrem no período da manhã, assim como as femininas. Sendo assim, embora haja visitação de insetos durante todo o dia, o processo de polinização ocorre no período matutino, em razão da quase total ausência de pólen no período vespertino.<br>The knowledge of the floral structure and reproductive biology are basic to a more successful for the development of techniques of castration and pollination in plant species. Aiming to obtain data about reproductive biology of physyc nut, free and enclosed inflorescences were observed without isolation (positive control) and isolation with nylon for posterior treatment of geitonogamy and xenogamy. So, treatments were positive control (free or unbagged inflorescences), and all other treatments obtained from isolated immature inflorescences enclosed within of fine nylon bags: negative control (without pollination), xenogamy (receiving pollen from another plant); geitonogamy 1 (received pollen from the same inflorescence), geitonogamy 2 (received pollen from another inflorescence of the same plant). The results indicate that the species does not present problems of self-incompatibility resulting in high fertilization and statistically indifferent in all treatments, presenting values above 80%, except for negative control in which the inflorescences were isolated and not pollinated resulting in lack of fertilization and fruit development. These results show the importance insects for success in the reproductive process of this species. The male flowers, pollen donors, opened in the morning, just like the female ones. Thus, although there is visitation of insects during all the day, the process of pollination occurs in the morning, and almost total absence of pollen was observed after noon