Project description:Actinobacteria are a rich source of bioactive molecules, and genome sequencing has shown that the vast majority of their biosynthetic potential has yet to be explored. However, many of their biosynthetic gene clusters (BGCs) are poorly expressed in the laboratory, which prevents discovery of their cognate natural products. To exploit their full biosynthetic potential, better understanding of the signals that promote the expression of BGCs is needed. Here, we show that the human stress hormone epinephrine (adrenaline) elicits antibiotic production by Actinobacteria. Catechol was established as the likely eliciting moiety, since similar responses were seen for catechol and for the catechol-containing molecules dopamine and catechin but not for related molecules. Exploration of the catechol-responsive strain Streptomyces sp. MBT84 using mass spectral networking revealed elicitation of a BGC that produces the angucycline glycosides aquayamycin, urdamycinone B and galtamycin C. Heterologous expression of the catechol-cleaving enzymes catechol 1,2-dioxygenase or catechol 2,3 dioxygenase counteracted the eliciting effect of catechol. Thus, for the first time we show the activation of natural product biosynthesis by a human hormone, leading to the identification of the ubiquitous catechol moiety as elicitor of BGCs for siderophores and antibiotics.
Project description:Actinobacteria are a rich source of bioactive molecules, and genome sequencing has shown that the vast majority of their biosynthetic potential has yet to be explored. However, many of their biosynthetic gene clusters (BGCs) are poorly expressed in the laboratory, which prevents discovery of their cognate natural products. To exploit their full biosynthetic potential, better understanding of the signals that promote the expression of BGCs is needed. Here, we show that the human stress hormone epinephrine (adrenaline) elicits antibiotic production by Actinobacteria. Catechol was established as the likely eliciting moiety, since similar responses were seen for catechol and for the catechol-containing molecules dopamine and catechin but not for related molecules. Exploration of the catechol-responsive strain Streptomyces sp. MBT84 using mass spectral networking revealed elicitation of a BGC that produces the angucycline glycosides aquayamycin, urdamycinone B and galtamycin C. Heterologous expression of the catechol-cleaving enzymes catechol 1,2-dioxygenase or catechol 2,3 dioxygenase counteracted the eliciting effect of catechol. Thus, for the first time we show the activation of natural product biosynthesis by a human hormone, leading to the identification of the ubiquitous catechol moiety as elicitor of BGCs for siderophores and antibiotics.
Project description:Streptomyces genome sequencing and assembly for determination of biosynthetic potential and structure elucidation of novel antimicrobials
Project description:Light is a source of energy and an environmental cue that is available in excess in most surface environments. In prokaryotic systems, conversion of light to energy by photoautotrophs and photoheterotrophs is well understood, but the conversion of light to information and the cellular response to that information has been characterized in only a few species. Our goal was to explore the response of freshwater Actinobacteria, which are ubiquitous in illuminated aquatic environments, to light. We found that Actinobacteria without functional photosystems grow faster in the light, likely because sugar transport and metabolism are upregulated in the light, while protein synthesis is upregulated in the dark. Based on the action spectrum of the growth effect, and comparisons of the genomes of three Actinobacteria with this growth rate phenotype, we propose that the photosensor in these strains is a putative CryB-type cryptochrome. The ability to sense light and upregulate carbohydrate transport during the day could allow these cells to coordinate their time of maximum organic carbon uptake with the time of maximum organic carbon release by primary producers.
Project description:Streptomyces sp. M7 has demonstrated ability to remove lindane from culture media and soils. In this study, we used MS-based label-free quantitative proteomic to understand lindane degradation and its metabolic context in Streptomyces sp. M7. We identified the proteins involved in the up-stream degradation pathway. Our results demonstrated that mineralization of lindane is feasible since proteins from an unusual down-stream degradation pathway were also identified. Degradative steps were supported by an active catabolism that supplied energy and reducing equivalents in the form of NADPH. This is the first study in which degradation steps of an organochlorine compound and metabolic context are elucidate in a biotechnological genus as Streptomyces. These results serve as basement to study other degradative actinobacteria and to improve the degradation processes of Streptomyces sp. M7.
Project description:The rapid rise in antibiotic-resistance of microbial pathogens has brought the attention to new, heterologous approaches to better exploit the vast repertoire of biosynthetic gene clusters in Actinobacteria genomes and the large number of potentially novel bioactive compounds encoded in these. To enable and optimize production of these compounds, a better understanding of -among others- the interplay between primary and secondary metabolism in the selected suitable heterologous production hosts is needed, in our case the model Streptomycete Streptomyces coelicolor. In this study, a genome-scale metabolic model is reconstructed based on several previous metabolic models and refined by including experimental data, in particular proteome data. This new consensus model provides not only a valuable and more accurate mathematical representation to predict steady-state flux distributions in this strain, but also provides a new framework for interpretation and integration of different 'omics' data by the Streptomyces research community for improved strain-specific systems-scale knowledge to be used in targeted strain development, e.g. for efficient new antibiotics production.