scholarly journals Dudomycins: New Secondary Metabolites Produced after Heterologous Expression of an Nrps Cluster from Streptomyces albus ssp. Chlorinus Nrrl B-24108

2020 ◽  
Vol 8 (11) ◽  
pp. 1800
Author(s):  
Constanze Lasch ◽  
Marc Stierhof ◽  
Marta Rodríguez Estévez ◽  
Maksym Myronovskyi ◽  
Josef Zapp ◽  
...  

Since the 1950s, natural products of bacterial origin were systematically developed to be used as drugs with a wide range of medical applications. The available treatment options for many diseases are still not satisfying, wherefore, the discovery of new structures has not lost any of its importance. Beyond the great variety of already isolated and characterized metabolites, Streptomycetes still harbor uninvestigated gene clusters whose products can be accessed using heterologous expression in host organisms. This works presents the discovery of a set of structurally novel secondary metabolites, dudomycins A to D, through the expression of a cryptic NRPS cluster from Streptomyces albus ssp. Chlorinus NRRL B-24108 in the heterologous host strain Streptomyces albus Del14. A minimal set of genes, required for the production of dudomycins, was defined through gene inactivation experiments. This paper also proposes a model for dudomycin biosynthesis.

Metabolites ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 13
Author(s):  
Paul F. Zierep ◽  
Adriana T. Ceci ◽  
Ilia Dobrusin ◽  
Sinclair C. Rockwell-Kollmann ◽  
Stefan Günther

Microorganisms produce secondary metabolites with a remarkable range of bioactive properties. The constantly increasing amount of published genomic data provides the opportunity for efficient identification of biosynthetic gene clusters by genome mining. On the other hand, for many natural products with resolved structures, the encoding biosynthetic gene clusters have not been identified yet. Of those secondary metabolites, the scaffolds of nonribosomal peptides and polyketides (type I modular) can be predicted due to their building block-like assembly. SeMPI v2 provides a comprehensive prediction pipeline, which includes the screening of the scaffold in publicly available natural compound databases. The screening algorithm was designed to detect homologous structures even for partial, incomplete clusters. The pipeline allows linking of gene clusters to known natural products and therefore also provides a metric to estimate the novelty of the cluster if a matching scaffold cannot be found. Whereas currently available tools attempt to provide comprehensive information about a wide range of gene clusters, SeMPI v2 aims to focus on precise predictions. Therefore, the cluster detection algorithm, including building block generation and domain substrate prediction, was thoroughly refined and benchmarked, to provide high-quality scaffold predictions. In a benchmark based on 559 gene clusters, SeMPI v2 achieved comparable or better results than antiSMASH v5. Additionally, the SeMPI v2 web server provides features that can help to further investigate a submitted gene cluster, such as the incorporation of a genome browser, and the possibility to modify a predicted scaffold in a workbench before the database screening.


2021 ◽  
Vol 11 (4) ◽  
pp. 1851
Author(s):  
Van Thuy Thi Pham ◽  
Chung Thanh Nguyen ◽  
Dipesh Dhakal ◽  
Hue Thi Nguyen ◽  
Tae-Su Kim ◽  
...  

Streptomyces is a significant source of natural products that are used as therapeutic antibiotics, anticancer and antitumor agents, pesticides, and dyes. Recently, with the advances in metabolite analysis, many new secondary metabolites have been characterized. Moreover, genome mining approaches demonstrate that many silent and cryptic biosynthetic gene clusters (BGCs) and many secondary metabolites are produced in very low amounts under laboratory conditions. One strain many compounds (OSMAC), overexpression/deletion of regulatory genes, ribosome engineering, and promoter replacement have been utilized to activate or enhance the production titer of target compounds. Hence, the heterologous expression of BGCs by transferring to a suitable production platform has been successfully employed for the detection, characterization, and yield quantity production of many secondary metabolites. In this review, we introduce the systematic approach for the heterologous production of secondary metabolites from Streptomyces in Streptomyces and other hosts, the genome analysis tools, the host selection, and the development of genetic control elements for heterologous expression and the production of secondary metabolites.


2015 ◽  
Vol 112 (10) ◽  
pp. 3086-3091 ◽  
Author(s):  
Rachel Bleich ◽  
Jeramie D. Watrous ◽  
Pieter C. Dorrestein ◽  
Albert A. Bowers ◽  
Elizabeth A. Shank

Bacteria have evolved the ability to produce a wide range of structurally complex natural products historically called “secondary” metabolites. Although some of these compounds have been identified as bacterial communication cues, more frequently natural products are scrutinized for antibiotic activities that are relevant to human health. However, there has been little regard for how these compounds might otherwise impact the physiology of neighboring microbes present in complex communities. Bacillus cereus secretes molecules that activate expression of biofilm genes in Bacillus subtilis. Here, we use imaging mass spectrometry to identify the thiocillins, a group of thiazolyl peptide antibiotics, as biofilm matrix-inducing compounds produced by B. cereus. We found that thiocillin increased the population of matrix-producing B. subtilis cells and that this activity could be abolished by multiple structural alterations. Importantly, a mutation that eliminated thiocillin’s antibiotic activity did not affect its ability to induce biofilm gene expression in B. subtilis. We go on to show that biofilm induction appears to be a general phenomenon of multiple structurally diverse thiazolyl peptides and use this activity to confirm the presence of thiazolyl peptide gene clusters in other bacterial species. Our results indicate that the roles of secondary metabolites initially identified as antibiotics may have more complex effects—acting not only as killing agents, but also as specific modulators of microbial cellular phenotypes.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4504
Author(s):  
Muhanna Al-shaibani ◽  
Radin Maya Saphira Radin Mohamed ◽  
Nik Sidik ◽  
Hesham Enshasy ◽  
Adel Al-Gheethi ◽  
...  

The current review aims to summarise the biodiversity and biosynthesis of novel secondary metabolites compounds, of the phylum Actinobacteria and the diverse range of secondary metabolites produced that vary depending on its ecological environments they inhabit. Actinobacteria creates a wide range of bioactive substances that can be of great value to public health and the pharmaceutical industry. The literature analysis process for this review was conducted using the VOSviewer software tool to visualise the bibliometric networks of the most relevant databases from the Scopus database in the period between 2010 and 22 March 2021. Screening and exploring the available literature relating to the extreme environments and ecosystems that Actinobacteria inhabit aims to identify new strains of this major microorganism class, producing unique novel bioactive compounds. The knowledge gained from these studies is intended to encourage scientists in the natural product discovery field to identify and characterise novel strains containing various bioactive gene clusters with potential clinical applications. It is evident that Actinobacteria adapted to survive in extreme environments represent an important source of a wide range of bioactive compounds. Actinobacteria have a large number of secondary metabolite biosynthetic gene clusters. They can synthesise thousands of subordinate metabolites with different biological actions such as anti-bacterial, anti-parasitic, anti-fungal, anti-virus, anti-cancer and growth-promoting compounds. These are highly significant economically due to their potential applications in the food, nutrition and health industries and thus support our communities’ well-being.


2020 ◽  
Author(s):  
Audam Chhun ◽  
Despoina Sousoni ◽  
Maria del Mar Aguiló-Ferretjans ◽  
Lijiang Song ◽  
Christophe Corre ◽  
...  

AbstractBacteria from the Actinomycete family are a remarkable source of natural products with pharmaceutical potential. The discovery of novel molecules from these organisms is, however, hindered because most of the biosynthetic gene clusters (BGCs) encoding these secondary metabolites are cryptic or silent and are referred to as orphan BGCs. While co-culture has proven to be a promising approach to unlock the biosynthetic potential of many microorganisms by activating the expression of these orphan BGCs, it still remains an underexplored technique. The marine actinobacteria Salinispora tropica, for instance, produces valuable compounds such as the anti-cancer molecule salinosporamide A but half of its putative BGCs are still orphan. Although previous studies have looked into using marine heterotrophs to induce orphan BGCs in Salinispora, the potential impact of co-culturing marine phototrophs with Salinispora has yet to be investigated. Following the observation of clear antimicrobial phenotype of the actinobacterium on a range of phytoplanktonic organisms, we here report the discovery of novel cryptic secondary metabolites produced by S. tropica in response to its co-culture with photosynthetic primary producers. An approach combining metabolomics and proteomics revealed that the photosynthate released by phytoplankton influences the biosynthetic capacities of S. tropica with both production of new molecules and the activation of orphan BGCs. Our work pioneers the use of phototrophs as a promising strategy to accelerate the discovery of novel natural products from actinobacteria.ImportanceThe alarming increase of antimicrobial resistance has generated an enormous interest in the discovery of novel active compounds. The isolation of new microbes to untap novel natural products is currently hampered because most biosynthetic gene clusters (BGC) encoded by these microorganisms are not expressed under standard laboratory conditions, i.e. mono-cultures. Here we show that co-culturing can be an easy way for triggering silent BGC. By combining state-of-the-art metabolomics and high-throughput proteomics, we characterized the activation of cryptic metabolites and silent biosynthetic gene clusters in the marine actinobacteria Salinispora tropica by the presence of phytoplankton photosynthate. We further suggest a mechanistic understanding of the antimicrobial effect this actinobacterium has on a broad range of prokaryotic and eukaryotic phytoplankton species and reveal a promising candidate for antibiotic production.


2021 ◽  
Author(s):  
◽  
Luke Stevenson

<p>Antibiotic discovery rates dramatically declined following the “golden age” of the 1940’s to the 1960’s. The platforms that underpinned that age of discovery rested upon laboratory cultivation of a small clade of bacteria, the actinomycetes, primarily isolated from soil environments. Fermentation extracts of these isolated bacteria have provided the majority of antibiotics and anticancer small molecules still used today. By applying modern genetic analysis techniques to these same environmental sources that have previously yielded such success, we can uncover new biosynthetic pathways, and bioactive compounds. The work described in this thesis investigated New Zealand soil metagenomes for this purpose.  Four large metagenome libraries were constructed from the microbiomes of diverse soil environments. These were then interrogated by a functional screening approach in a knockout Escherichia coli strain, to recover a large collection of the biosynthetic gene clusters responsible for bacterial secondary metabolite production. Using different modes of bioinformatic analysis, these gene clusters were demonstrated to have both phylogenetic divergence, and functional difference from bacterial biosynthesis pathways previously discovered from culture based studies.  Two additional biosynthetic pathways were recovered from one of these metagenome libraries, and in each case found to have novel genetic features. These gene clusters were further studied by heterologous expression within Streptomyces albus production hosts. One of these gene clusters produced small aromatic polyketide compounds, the structure of one of which was solved by chemical analytic techniques, and found to be a new chemical entity.  The second gene cluster was demonstrated to have similarity to known aureolic acid biosynthesis gene clusters – a class of potent anticancer natural products. Heterologous expression resulted in the production of many metabolites, two of which were characterised and found to be new members of this chemical class.  The research in this thesis both validates the use of metagenomic analysis for future natural product discovery efforts, and adds to a growing body of evidence that understudied clades of bacteria have an untapped biosynthetic potential that can be accessed by metagenomic methods.</p>


Medicines ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 32 ◽  
Author(s):  
Ray Chen ◽  
Hon Wong ◽  
Brendan Burns

Microorganisms in the environment can produce a diverse range of secondary metabolites (SM), which are also known as natural products. Bioactive SMs have been crucial in the development of antibiotics and can also act as useful compounds in the biotechnology industry. These natural products are encoded by an extensive range of biosynthetic gene clusters (BGCs). The developments in omics technologies and bioinformatic tools are contributing to a paradigm shift from traditional culturing and screening methods to bioinformatic tools and genomics to uncover BGCs that were previously unknown or transcriptionally silent. Natural product discovery using bioinformatics and omics workflow in the environment has demonstrated an extensive distribution of BGCs in various environments, such as soil, aquatic ecosystems and host microbiome environments. Computational tools provide a feasible and culture-independent route to find new secondary metabolites where traditional approaches cannot. This review will highlight some of the advances in the approaches, primarily bioinformatic, in identifying new BGCs, especially in environments where microorganisms are rarely cultured. This has allowed us to tap into the huge potential of microbial dark matter.


2019 ◽  
Vol 85 (23) ◽  
Author(s):  
Juan Pablo Gomez-Escribano ◽  
Jean Franco Castro ◽  
Valeria Razmilic ◽  
Scott A. Jarmusch ◽  
Gerhard Saalbach ◽  
...  

ABSTRACT Analysis of the genome sequence of Streptomyces leeuwenhoekii C34T identified biosynthetic gene clusters (BGCs) for three different lasso peptides (Lp1, Lp2, and Lp3) which were not known to be made by the strain. Lasso peptides represent relatively new members of the RiPP (ribosomally synthesized and posttranslationally modified peptides) family of natural products and have not been extensively studied. Lp3, whose production could be detected in culture supernatants from S. leeuwenhoekii C34T and after heterologous expression of its BGC in Streptomyces coelicolor, is identical to the previously characterized chaxapeptin. Lp1, whose production could not be detected or achieved heterologously, appears to be identical to a recently identified member of the citrulassin family of lasso peptides. Since production of Lp2 by S. leeuwenhoekii C34T was not observed, its BGC was also expressed in S. coelicolor. The lasso peptide was isolated and its structure confirmed by mass spectrometry and nuclear magnetic resonance analyses, revealing a novel structure that appears to represent a new family of lasso peptides. IMPORTANCE Recent developments in genome sequencing combined with bioinformatic analysis have revealed that actinomycetes contain a plethora of unexpected BGCs and thus have the potential to produce many more natural products than previously thought. This reflects the inability to detect the production of these compounds under laboratory conditions, perhaps through the use of inappropriate growth media or the absence of the environmental cues required to elicit expression of the corresponding BGCs. One approach to overcoming this problem is to circumvent the regulatory mechanisms that control expression of the BGC in its natural host by deploying heterologous expression. The generally compact nature of lasso peptide BGCs makes them particularly amenable to this approach, and, in the example given here, analysis revealed a new member of the lasso peptide family of RiPPs. This approach should be readily applicable to other cryptic lasso peptide gene clusters and would also facilitate the design and production of nonnatural variants by changing the sequence encoding the core peptide, as has been achieved with other classes of RiPPs.


2020 ◽  
Vol 9 (21) ◽  
Author(s):  
Anna Tippelt ◽  
Markus Nett ◽  
M. Soledad Vela Gurovic

ABSTRACT Streptomyces albus CAS922 was isolated from sunflower seed hulls. Its fully sequenced genome harbors a multitude of genes for carbohydrate-active enzymes, which likely facilitate growth on lignocellulosic biomass. Furthermore, the presence of 27 predicted biosynthetic gene clusters indicates a significant potential for the production of bioactive secondary metabolites.


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