RESUMO
In this study, delta-12 desaturase was overexpressed in Yarrowia lipolytica using the single-copy integrative vector pINA1312 and multicopy integrative vector pINA1292, resulting in the engineered yeast strains 1312-12 and 1292-12, respectively. The content of intracellular linoleic acid (LA) in the 1292-12 strain was much higher than in the 1312-12 strain and the control group. One interesting finding was that the 1292-12 strain showed obvious changes in surface morphology. The 1292-12 colonies were much smaller and smoother, whereas their single cells became much larger compared to the control strain. In addition, the dry cell weight (DCW) of the 1292-12 strain was obviously increased from 8.5 to 12.7 g/L, but the viable cell number sharply decreased from 107 to 105/mL. These results indicated that increased LA content in Yarrowia lipolytica could induce morphological changes or even oxidative stress-dependent cell death. The reactive oxygen species (ROS) and malondialdehyde (MDA) were accumulated in the 1292-12 strain, while the antioxidant activities of intracellular catalase (CAT) and superoxide dismutase (SOD) were significantly decreased by 27.6 and 32.0%, respectively. Furthermore, it was also revealed that these issues could be ameliorated by the exogenous supplementation of vitamin C, fish and colza oil.
RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Anisophyllea laurina R. Br ex Sabine is a plant that has been used in the folk medicine to treat malaria, dysentery, diabetes and toothache against bacterial infection. Through this study, most likely we are reporting for the first time, its effectiveness as an antibacterial and antifungal agent. AIM OF THE STUDY: To evaluate antibacterial and antifungal activities of various solvent extracts from the leaves and stem bark of A. laurina R. Br ex Sabine. MATERIALS AND METHODS: The various solvent extracts of leaves and stem bark were tested for antibacterial and antifungal activities against eight bacteria strains and three fungal strains using the well diffusion and micro-dilution methods. RESULTS: Antibacterial and antifungal activities of methanol and ethanol extracts were higher than the ethyl acetate and water extract. Leaves extracts had the highest potential activity against bacteria than stem bark extracts, but showed low antifungal activity compared to stem bark extracts. They also exhibited potent growth inhibitory activity against Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli ATCC 8739 and Bacillus subtilis with MIC value of 125µg/mL. CONCLUSIONS: The current study confirmed that the leaves and stem bark extracts of A. laurina R. Br ex Sabine proved to be most effective as antibacterial and antifungal activities.