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This review constitutes a summary of current knowledge on GlnR, a global regulator, that assumes a critical function in the regulation of nitrogen metabolism of Actinomycetes. In cross-regulation with other regulators, GlnR was also shown to play a role in the regulation of carbon and phosphate metabolisms as well as of secondary metabolism. A description of the structure of the GlnR protein and of its binding sites in various genes promoters regions is also provided. This review thus provides a global understanding of the critical function played by GlnR in the regulation of primary and secondary metabolism in Actinomycetes. [ABSTRACT FROM AUTHOR]

Butenyl-spinosyn, a highly effective biological insecticide, is produced by Saccharopolyspora pogona. However, its application has been severely hampered by its low yield. Recent studies have shown that PhoU plays a pivotal role in regulating cell growth, secondary metabolite biosynthesis and intracellular phosphate levels. Nevertheless, the function of PhoU remains ambiguous in S. pogona. In this study, we investigated the effects of PhoU on the growth and the butenyl-spinosyn biosynthesis of S. pogona by constructing the mutants. Overexpression of phoU increased the production of butenyl-spinosyn to 2.2-fold that of the wild-type strain. However, the phoU deletion resulted in a severe imbalance of intracellular phosphate levels, and suppression of the growth and butenyl-spinosyn biosynthesis. Quantitative Real-time PCR (qRT-PCR) analysis, distinctive protein detection and mass spectrometry revealed that PhoU widely regulated primary metabolism, energy metabolism and DNA repair, which implied that PhoU influences the growth and butenyl-spinosyn biosynthesis of S. pogona as a global regulator. [ABSTRACT FROM AUTHOR]

Butenyl-spinosyn, a highly effective biological insecticide, is produced by Saccharopolyspora pogona. However, its application has been severely hampered by its low yield. Recent studies have shown that PhoU plays a pivotal role in regulating cell growth, secondary metabolite biosynthesis and intracellular phosphate levels. Nevertheless, the function of PhoU remains ambiguous in S. pogona. In this study, we investigated the effects of PhoU on the growth and the butenyl-spinosyn biosynthesis of S. pogona by constructing the mutants. Overexpression of phoU increased the production of butenyl-spinosyn to 2.2-fold that of the wild-type strain. However, the phoU deletion resulted in a severe imbalance of intracellular phosphate levels, and suppression of the growth and butenyl-spinosyn biosynthesis. Quantitative Real-time PCR (qRT-PCR) analysis, distinctive protein detection and mass spectrometry revealed that PhoU widely regulated primary metabolism, energy metabolism and DNA repair, which implied that PhoU influences the growth and butenyl-spinosyn biosynthesis of S. pogona as a global regulator.

Transcription regulation caused by global regulators exerts important effects on fungal secondary metabolism. By overexpression of the global regulator Talae1 in a Ficus elastica-associated fungus Trichoderma afroharzianum, two structurally new polyketides (1 and 2) that were newly produced in the transformant were isolated and identified. Their structures, including the absolute configurations, were elucidated through a combination of high resolution mass spectrometer (HRMS), NMR, and electronic circular dichroism (ECD) calculations. The growth inhibitory activities of compounds 1 and 2 were evaluated against four bacteria and six plant-pathogenic fungi. Compound 1 showed the highest antifungal activity against Botrytis cinerea and Fusarium oxysporum f. sp. nicotianae with MIC of 8 μg/ml. To the best of our knowledge, this is the first study to report on the application of the global regulator in T. afroharzianum to activate the biosynthesis of bioactive secondary metabolites.

Transcription regulation caused by global regulators exerts important effects on fungal secondary metabolism. By overexpression of the global regulator Talae1 in a Ficus elastica -associated fungus Trichoderma afroharzianum , two structurally new polyketides (1 and 2) that were newly produced in the transformant were isolated and identified. Their structures, including the absolute configurations, were elucidated through a combination of high resolution mass spectrometer (HRMS), NMR, and electronic circular dichroism (ECD) calculations. The growth inhibitory activities of compounds 1 and 2 were evaluated against four bacteria and six plant-pathogenic fungi. Compound 1 showed the highest antifungal activity against Botrytis cinerea and Fusarium oxysporum f. sp. nicotianae with MIC of 8 μg/ml. To the best of our knowledge, this is the first study to report on the application of the global regulator in T. afroharzianum to activate the biosynthesis of bioactive secondary metabolites. [ABSTRACT FROM AUTHOR]

The extensive use of acids in a variety of manufacturing industries results in the increase of discharged acidic waste stream into the environment. Such co-pollution of acids and other organic pollutants limits the biodegradation capability of neutrophilic degraders. With high-throughput genetic techniques, we aim to improve the acid tolerance of a pollutant-degrading bacterium, Pseudomonas putida S16 by genetically engineering it with the glutamate decarboxylase (GAD)-dependent system and the global regulator (IrrE) of extreme radiation resistance. The engineered strains holding either GAD system or irrE regulator could grow under pH 4.5, compared to the wild type. They could also degrade over 90% of a selected pollutant (benzoate or nicotine) under pH 5.0 in 48 h, while no biodegradation was detected with the wild type under the same conditions. We conclude that acid stress tolerance by the possession of the GAD system or IrrE regulator in pollutant-degrading bacteria would be a promising approach to enhance their viability and biodegrading activities in bioremediation of acidic wastes.

The extensive use of acids in a variety of manufacturing industries results in the increase of discharged acidic waste stream into the environment. Such co-pollution of acids and other organic pollutants limits the biodegradation capability of neutrophilic degraders. With high-throughput genetic techniques, we aim to improve the acid tolerance of a pollutant-degrading bacterium, Pseudomonas putida S16 by genetically engineering it with the glutamate decarboxylase (GAD)-dependent system and the global regulator (IrrE) of extreme radiation resistance. The engineered strains holding either GAD system or irrE regulator could grow under pH 4.5, compared to the wild type. They could also degrade over 90% of a selected pollutant (benzoate or nicotine) under pH 5.0 in 48 h, while no biodegradation was detected with the wild type under the same conditions. We conclude that acid stress tolerance by the possession of the GAD system or IrrE regulator in pollutant-degrading bacteria would be a promising approach to enhance their viability and biodegrading activities in bioremediation of acidic wastes. [ABSTRACT FROM AUTHOR]