scholarly journals Warum Mikroorganismen Naturstoffe produzieren

BIOspektrum ◽  
2020 ◽  
Vol 26 (7) ◽  
pp. 731-733
Author(s):  
Mario K. C. Krespach ◽  
Maria C. Stroe ◽  
Axel A. Brakhage

AbstractA key role in the communication between fungi and bacteria is played by natural products. Many of their encoding gene clusters are silent under standard laboratory conditions. Interspecies “talk” between microorganisms represents an ecological trigger to activate such silent gene clusters and leads to the formation of novel natural products by the involved species. The understanding of both the activation of silent gene clusters and the ecological function of the produced compounds is of importance to reveal functional microbial interactions required to shape microbiomes.

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Maria Cristina Stroe ◽  
Tina Netzker ◽  
Kirstin Scherlach ◽  
Thomas Krüger ◽  
Christian Hertweck ◽  
...  

Microorganisms produce numerous secondary metabolites (SMs) with various biological activities. Many of their encoding gene clusters are silent under standard laboratory conditions because for their activation they need the ecological context, such as the presence of other microorganisms. The true ecological function of most SMs remains obscure, but understanding of both the activation of silent gene clusters and the ecological function of the produced compounds is of importance to reveal functional interactions in microbiomes. Here, we report the identification of an as-yet uncharacterized silent gene cluster of the fungus Aspergillus fumigatus, which is activated by the bacterium Streptomyces rapamycinicus during the bacterial-fungal interaction. The resulting natural product is the novel fungal metabolite fumigermin, the biosynthesis of which requires the polyketide synthase FgnA. Fumigermin inhibits germination of spores of the inducing S. rapamycinicus, and thus helps the fungus to defend resources in the shared habitat against a bacterial competitor.


Marine Drugs ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 20
Author(s):  
Tiago Leão ◽  
Mingxun Wang ◽  
Nathan Moss ◽  
Ricardo da Silva ◽  
Jon Sanders ◽  
...  

Microbial natural products are important for the understanding of microbial interactions, chemical defense and communication, and have also served as an inspirational source for numerous pharmaceutical drugs. Tropical marine cyanobacteria have been highlighted as a great source of new natural products, however, few reports have appeared wherein a multi-omics approach has been used to study their natural products potential (i.e., reports are often focused on an individual natural product and its biosynthesis). This study focuses on describing the natural product genetic potential as well as the expressed natural product molecules in benthic tropical cyanobacteria. We collected from several sites around the world and sequenced the genomes of 24 tropical filamentous marine cyanobacteria. The informatics program antiSMASH was used to annotate the major classes of gene clusters. BiG-SCAPE phylum-wide analysis revealed the most promising strains for natural product discovery among these cyanobacteria. LCMS/MS-based metabolomics highlighted the most abundant molecules and molecular classes among 10 of these marine cyanobacterial samples. We observed that despite many genes encoding for peptidic natural products, peptides were not as abundant as lipids and lipopeptides in the chemical extracts. Our results highlight a number of highly interesting biosynthetic gene clusters for genome mining among these cyanobacterial samples.


Author(s):  
Zhenyu Liu ◽  
Yatong Zhao ◽  
Chaoqun Huang ◽  
Yunzi Luo

Natural products (NPs) are critical sources of drug molecules for decades. About two-thirds of natural antibiotics are produced by Streptomyces. Streptomyces have a large number of secondary metabolite biosynthetic gene clusters (SM-BGCs) that may encode NPs. However, most of these BGCs are silent under standard laboratory conditions. Hence, activation of these silent BGCs is essential to current natural products discovery research. In this review, we described the commonly used strategies for silent BGC activation in Streptomyces from two aspects. One focused on the strategies applied in heterologous host, including methods to clone and reconstruct BGCs along with advances in chassis engineering; the other focused on methods applied in native host which includes engineering of promoters, regulatory factors, and ribosomes. With the metabolic network being elucidated more comprehensively and methods optimized more high-thoroughly, the discovery of NPs will be greatly accelerated.


2018 ◽  
Vol 115 (15) ◽  
pp. 3758-3763 ◽  
Author(s):  
Johannes Arp ◽  
Sebastian Götze ◽  
Ruchira Mukherji ◽  
Derek J. Mattern ◽  
María García-Altares ◽  
...  

Investigating microbial interactions from an ecological perspective is a particularly fruitful approach to unveil both new chemistry and bioactivity. Microbial predator–prey interactions in particular rely on natural products as signal or defense molecules. In this context, we identified a grazing-resistant Pseudomonas strain, isolated from the bacterivorous amoeba Dictyostelium discoideum. Genome analysis of this bacterium revealed the presence of two biosynthetic gene clusters that were found adjacent to each other on a contiguous stretch of the bacterial genome. Although one cluster codes for the polyketide synthase producing the known antibiotic mupirocin, the other cluster encodes a nonribosomal peptide synthetase leading to the unreported cyclic lipopeptide jessenipeptin. We describe its complete structure elucidation, as well as its synergistic activity against methicillin-resistant Staphylococcus aureus, when in combination with mupirocin. Both biosynthetic gene clusters are regulated by quorum-sensing systems, with 3-oxo-decanoyl homoserine lactone (3-oxo-C10-AHL) and hexanoyl homoserine lactone (C6-AHL) being the respective signal molecules. This study highlights the regulation, richness, and complex interplay of bacterial natural products that emerge in the context of microbial competition.


2021 ◽  
Vol 118 (45) ◽  
pp. e2100892118
Author(s):  
Mario K. C. Krespach ◽  
Maria C. Stroe ◽  
Michal Flak ◽  
Anna J. Komor ◽  
Sandor Nietzsche ◽  
...  

Photosynthetic microorganisms including the green alga Chlamydomonas reinhardtii are essential to terrestrial habitats as they start the carbon cycle by conversion of CO2 to energy-rich organic carbohydrates. Terrestrial habitats are densely populated, and hence, microbial interactions mediated by natural products are inevitable. We previously discovered such an interaction between Streptomyces iranensis releasing the marginolactone azalomycin F in the presence of C. reinhardtii. Whether the alga senses and reacts to azalomycin F remained unknown. Here, we report that sublethal concentrations of azalomycin F trigger the formation of a protective multicellular structure by C. reinhardtii, which we named gloeocapsoid. Gloeocapsoids contain several cells which share multiple cell membranes and cell walls and are surrounded by a spacious matrix consisting of acidic polysaccharides. After azalomycin F removal, gloeocapsoid aggregates readily disassemble, and single cells are released. The presence of marginolactone biosynthesis gene clusters in numerous streptomycetes, their ubiquity in soil, and our observation that other marginolactones such as desertomycin A and monazomycin also trigger the formation of gloeocapsoids suggests a cross-kingdom competition with ecological relevance. Furthermore, gloeocapsoids allow for the survival of C. reinhardtii at alkaline pH and otherwise lethal concentrations of azalomycin F. Their structure and polysaccharide matrix may be ancestral to the complex mucilage formed by multicellular members of the Chlamydomonadales such as Eudorina and Volvox. Our finding suggests that multicellularity may have evolved to endure the presence of harmful competing bacteria. Additionally, it underlines the importance of natural products as microbial cues, which initiate interesting ecological scenarios of attack and counter defense.


2018 ◽  
Author(s):  
Fabrizio Alberti ◽  
Daniel J. Leng ◽  
Ina Wilkening ◽  
Lijiang Song ◽  
Manuela Tosin ◽  
...  

AbstractHerein we report a strategy for the rapid and rational characterisation of novel microbial natural products from silent gene clusters. A conserved set of five regulatory genes was used as a query to search genomic databases and identify atypical biosynthetic gene clusters (BGCs). A 20-kb BGC from the genetically intractable Streptomyces sclerotialus bacterial strain was captured using yeast-based homologous recombination and introduced into validated heterologous hosts. CRISPR/Cas9-mediated genome editing was then employed to rationally inactivate the key transcriptional repressor and trigger production of an unprecedented class of hybrid natural products exemplified by (2-(benzoyloxy)acetyl)-L-proline, named scleric acid. Subsequent rounds of CRISPR/Cas9-mediated gene deletions afforded a selection of biosynthetic gene mutant strains which led to a plausible biosynthetic pathway for scleric acid assembly. Scleric acid and a key biosynthetic intermediate were also synthesised and used as authentic standards. The assembly of scleric acid involves two unique enzymatic condensation reactions that respectively link a proline and a benzoyl residue to each end of a rare hydroxyethyl-ACP intermediate. Scleric acid was then shown to exhibit moderate activity against Mycobacterium tuberculosis, as well as modest inhibition of the cancer-associated metabolic enzyme Nicotinamide N-methyltransferase (NNMT).


Author(s):  
Patrick Videau ◽  
Kaitlyn Wells ◽  
Arun Singh ◽  
Jessie Eiting ◽  
Philip Proteau ◽  
...  

Cyanobacteria are prolific producers of natural products and genome mining has shown that many orphan biosynthetic gene clusters can be found in sequenced cyanobacterial genomes. New tools and methodologies are required to investigate these biosynthetic gene clusters and here we present the use of <i>Anabaena </i>sp. strain PCC 7120 as a host for combinatorial biosynthesis of natural products using the indolactam natural products (lyngbyatoxin A, pendolmycin, and teleocidin B-4) as a test case. We were able to successfully produce all three compounds using codon optimized genes from Actinobacteria. We also introduce a new plasmid backbone based on the native <i>Anabaena</i>7120 plasmid pCC7120ζ and show that production of teleocidin B-4 can be accomplished using a two-plasmid system, which can be introduced by co-conjugation.


Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 107
Author(s):  
Rafael de Felício ◽  
Patricia Ballone ◽  
Cristina Freitas Bazzano ◽  
Luiz F. G. Alves ◽  
Renata Sigrist ◽  
...  

Bacterial genome sequencing has revealed a vast number of novel biosynthetic gene clusters (BGC) with potential to produce bioactive natural products. However, the biosynthesis of secondary metabolites by bacteria is often silenced under laboratory conditions, limiting the controlled expression of natural products. Here we describe an integrated methodology for the construction and screening of an elicited and pre-fractionated library of marine bacteria. In this pilot study, chemical elicitors were evaluated to mimic the natural environment and to induce the expression of cryptic BGCs in deep-sea bacteria. By integrating high-resolution untargeted metabolomics with cheminformatics analyses, it was possible to visualize, mine, identify and map the chemical and biological space of the elicited bacterial metabolites. The results show that elicited bacterial metabolites correspond to ~45% of the compounds produced under laboratory conditions. In addition, the elicited chemical space is novel (~70% of the elicited compounds) or concentrated in the chemical space of drugs. Fractionation of the crude extracts further evidenced minor compounds (~90% of the collection) and the detection of biological activity. This pilot work pinpoints strategies for constructing and evaluating chemically diverse bacterial natural product libraries towards the identification of novel bacterial metabolites in natural product-based drug discovery pipelines.


Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 298
Author(s):  
Despoina Konstantinou ◽  
Rafael V. Popin ◽  
David P. Fewer ◽  
Kaarina Sivonen ◽  
Spyros Gkelis

Sponges form symbiotic relationships with diverse and abundant microbial communities. Cyanobacteria are among the most important members of the microbial communities that are associated with sponges. Here, we performed a genus-wide comparative genomic analysis of the newly described marine benthic cyanobacterial genus Leptothoe (Synechococcales). We obtained draft genomes from Le. kymatousa TAU-MAC 1615 and Le. spongobia TAU-MAC 1115, isolated from marine sponges. We identified five additional Leptothoe genomes, host-associated or free-living, using a phylogenomic approach, and the comparison of all genomes showed that the sponge-associated strains display features of a symbiotic lifestyle. Le. kymatousa and Le. spongobia have undergone genome reduction; they harbored considerably fewer genes encoding for (i) cofactors, vitamins, prosthetic groups, pigments, proteins, and amino acid biosynthesis; (ii) DNA repair; (iii) antioxidant enzymes; and (iv) biosynthesis of capsular and extracellular polysaccharides. They have also lost several genes related to chemotaxis and motility. Eukaryotic-like proteins, such as ankyrin repeats, playing important roles in sponge-symbiont interactions, were identified in sponge-associated Leptothoe genomes. The sponge-associated Leptothoe stains harbored biosynthetic gene clusters encoding novel natural products despite genome reduction. Comparisons of the biosynthetic capacities of Leptothoe with chemically rich cyanobacteria revealed that Leptothoe is another promising marine cyanobacterium for the biosynthesis of novel natural products.


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