RESUMO
The aim of this study was to probe the potential anti-H. pylori activity of the synthetic antimicrobial peptide pexiganan, which is an analog of the peptide magainin, and its nanoparticles (PNPs) that were prepared in our laboratory. To compare their antibacterial effects in vitro and in vivo, studies of H. pylori growth inhibition, kinetics and resistance assays were undertaken. The gastric mucoadhesive efficiency and H. pylori clearance efficiency of pexiganan and PNPs were evaluated in rats and mice infected with H. pylori. The eradication of H. pylori was determined using urease tests and a microbial culture method. We observed that PNPs adhered to gastric mucosa more effectively owing to a prolonged stay in the stomach, which resulted in a more effective H. pylori clearance. In addition, PNPs had greater anti-H. pylori effect than pexiganan in infected mice. The amount of pexiganan required to eradicate H. pylori was significantly less using PNPs than the corresponding pexiganan suspension. The results confirmed that PNPs improved peptide stability in the stomach and more effectively eradicated H. pylori from mice stomachs than pexiganan.
Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Helicobacter pylori/efeitos dos fármacos , Nanopartículas/administração & dosagem , Peptídeos/farmacologia , Animais , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/microbiologia , Infecções por Helicobacter/tratamento farmacológico , Cinética , Masculino , Camundongos , Ratos , Ratos Sprague-DawleyRESUMO
Accumulating evidence has shown that hydrogen sulfide (H2S) acts as a signaling regulator in plants. Here we show that H2S delays the postharvest senescence of broccoli in a dose-dependent manner. H2S maintains higher levels of metabolites, such as carotenoids, anthocyanin, and ascorbate, and reduces the accumulation of malondialdehyde, H2O2, and the superoxide anion. Further investigations showed that H2S sustained higher activities of guaiacol peroxidase, ascorbate peroxidase, catalase, and glutathione reductase and lower activities of lipoxygenase, polyphenol oxidase, phenylalanine ammonia lyase, and protease than those of water control. Moreover, the expression of the chlorophyll degradation related genes BoSGR, BoCLH2, BoPaO, BoRCCR, as well as cysteine protease BoCP1 and lipoxygenase gene BoLOX1, was down-regulated in postharvest broccoli treated with H2S. The functions of H2S on the senescence of other vegetables and fruits suggest its universal role acting as a senescence regulator.
Assuntos
Antioxidantes/metabolismo , Brassica/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Sulfeto de Hidrogênio/farmacologia , Proteínas de Plantas/genética , Ascorbato Peroxidases/genética , Ascorbato Peroxidases/metabolismo , Brassica/enzimologia , Brassica/genética , Catalase/genética , Catalase/metabolismo , Senescência Celular/efeitos dos fármacos , Clorofila/genética , Clorofila/metabolismo , Malondialdeído/metabolismo , Peroxidase , Proteínas de Plantas/metabolismoRESUMO
This study employed a Bac-to-Bac/Bombyx mori bioreactor to mass-produce immunogenic urease subunit B (UreB) from Helicobacter pylori. The signal peptide bombyxin from B. mori was used to promote secretory expression to improve expression levels and was designed and integrated into the UreB gene to generate the Bacmid/BmNPV/(signal peptide)-UreB baculovirus expression system. To determine whether the bombyxin signal peptide resulted in secretory expression of recombinant UreB (rUreB) and to determine the secretory efficiency, we tested the secretory expression level of rUreB in Bm5 cells using ELISA. To further investigate whether secretory expression affected cell viability, cells were evaluated using 0.4% trypan blue staining, and Bacmid/BmNPV/UreB without the signal peptide served as a control. The above recombinant bacmid constructs were injected to silkworm larvae, and the secretory expression level of rUreB was detected using SDS-PAGE and semi-quantitative western blot analysis. The results indicated that the bombyxin signal peptide directed the secretory expression of rUreB and that this expression improved the viability of Bm5 cells. Moreover, the results showed that the expression level of rUreB was 1.5 times higher with the Bacmid/BmNPV constructs containing the bombyxin signal sequence than those without the signal sequence. These results demonstrate that secretory expression can enhance rUreB expression levels and is likely to aid in the large-scale expression and yield of rUreB in silkworm larvae.