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Angucyclines/angucyclinones are a large group of polycyclic aromatic polyketides and their producers are widely distributed in nature. This family of natural products attracts great attention because of their diverse biological activities and unique chemical structures. With the development of synthetic biology and the exploitation of the actinomycetes from previously unexplored environments, angucyclines/angucyclinones-like natural products with new skeletons were continuously discovered, thus enriching the structural diversity of this family. In this review we summarize the new angucyclines/angucyclinones analogues discovered in the last decade (2010-2020) by using different strategies, such as changing cultivation conditions, genetic modification, genome mining, bioactivity-guided compound isolation, and fermentation of actinomycetes from underexplored environments. We also discuss the role of synthetic biology in the discovery and development of new compounds of the angucycline/angucyclinone family.
Assuntos
Antraquinonas , Produtos Biológicos , Policetídeos , StreptomycesRESUMO
Objective:To study the effects of different drought conditions on the growth and photosynthetic physiological parameters of Acanthopanax senticosus，in order to provide the theoretical basis for standardized planting and rational development and utilization of A. senticosus. Method:In this study，three-year-old A. senticosus was used as experimental samples. The growth parameters，photosynthetic parameters，and photosynthetic physiological parameters were determined to study the effects of different drought conditions on the growth and photosynthesis of A. senticosus. Result:The plant height and leaf number were significantly lower than the control group under drought stress conditions，and the leaf area was higher than the control group under drought stress. Net photosynthetic rate，stomata conductance and transpiration rate were not significantly different between the control group and the moderate drought stress group. They were significantly decreased in the severe drought stress group，while the intercellular carbon dioxide concentration increased with the severity of drought stress. With the treatment time，the initial fluorescence was higher in the severe drought stress group than in the control group，and the moderate drought stress group was lower than the control group，the maximum fluorescence was significantly lower in the severe drought stress group than in the control group， potential photochemical efficiency and maximum photochemical efficiency were significantly elevated in the moderate drought stress group. Conclusion:Drought stress can significantly inhibit the growth of A. senticosus. Severe drought conditions can significantly inhibit the photosynthesis of A. senticosus leaves. This effect is related to the regulation of stomatal size，but not related to the activity of photoreaction center.
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Objective:To study the effect of different shading conditions on the growth and photosynthetic physiological parameters of Acanthopanax senticosus，and provide a theoretical basis for standardized planting and rational development and utilization of A. senticosus. Method:Three-year-old A. senticosus was used as the experimental sample.The growth parameters and photosynthetic physiological parameters of plant height，leaf number and leaf area were determined to study the effects of different shading conditions on the growth and photosynthesis of A. senticosus. Result:Plant height，leaf number，and leaf area were significantly higher in the shading treatment than in the control group，and highest under moderate shading conditions.The net photosynthetic rate，stomatal conductance，and transpiration rate were significantly higher in the moderate shading group than in the control group，and decreased in the severe shading group，while the intercellular carbon dioxide concentration was significantly lower in the moderate shading group than in the other treatment groups.As the treatment time progressed，the initial fluorescence was not significantly higher in the moderate shading group than in the control group，but significantly higher in the severe shading group；the maximum fluorescence was significantly higher in the shading group than in the control group，in the moderate shading group.The potential photochemical efficiency and maximum photochemical efficiency were not significantly different between the moderate shading group and the control group and decreased in the severe shading group，which was significantly lower than other treatment groups. Conclusion:Shading treatment is beneficial to the growth of A. senticosus.The moderate shading condition can significantly improve the photosynthesis of A. senticosus.Severe shading treatment can significantly inhibit the photosynthesis of A. senticosus leaves.This effect is related to the regulation of stomatal regulation. The activity of the photoreaction center is related.
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Abstract Microalgae are photosynthetic microorganisms whose composition and biomass production can be influenced by manipulating the cultivation conditions employed. However, few studies have evaluated the effects of various cultivation conditions in autotrophic and mixotrophic conditions. The present work aimed to evaluate the effects of cultivation conditions on the cell growth and biosynthesis of fatty acids (FAs) by microalgae of the genus Chlorella in autotrophic and mixotrophic cultivation. Evaluation of the effects of the conditions was performed using an experimental design methodology. The highest values of maximum biomass concentration (Xmax) and maximum biomass productivity (Pmax) were obtained in autotrophic cultures. Palmitic acid was the FA obtained at the highest concentration in both cultivation modes. The concentrations of polyunsaturated FAs (PUFAs) ranged from 12.2 to 41.2% in autotrophic cultures and from 11 to 34.3% in the mixotrophic cultures. The variables photoperiod and sodium bicarbonate concentration showed the greatest influence on the Xmax, Pmax, and PUFA concentration in autotrophic and mixotrophic cultivations, respectively. This study verified that the selection of conditions and mode of cultivation contribute to the production of microalgal biomass and FA biosynthesis.