Does Osmotic Stress Affect Natural Product Expression in Fungi?

Overy, David P.; Correa, Hebelin; Roullier, Catherine; Chiung, Wei; Pang, Ka Lai; Rateb, Mostafa E.; Ebel, Rainer; Shang, Zhuo; Capon, Robert J.; Bills, Gerald F.; Kerr, Russell G.

doi:10.3390/md15080254

Cited by 40 publications

(47 citation statements)

References 41 publications

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“…Our results illustrate medium-dependent changes of bioactivity. This has also previously been shown by Overy et al ( 2017 ) in a comprehensive study where the same ex-type strain of Aspergillus aculeatus , a halotolerant terrestrial fungus, produced distinct culture media-specific metabolites when grown with different osmotic pressures as well as laboratory (site) specific metabolites.…”

Section: Discussionsupporting

confidence: 76%

Cultivable marine fungi from the Arctic Archipelago of Svalbard and their antibacterial activity

et al. 2019

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During a research cruise in 2016, we isolated fungi from sediments, seawater, driftwood, fruiting bodies, and macroalgae using three different media to assess species richness and potential bioactivity of cultivable marine fungi in the High Arctic region. Ten stations from the Svalbard archipelago (73–80 °N, 18–31 °E) were investigated and 33 fungal isolates were obtained. These grouped into 22 operational taxonomic units (OTUs) using nuc rDNA internal transcribed spacer regions (ITS1-5.8S-ITS2 = ITS) with acut-off set at 98% similarity. The taxonomic analysis showed that 17 OTUs belonged to Ascomycota, one to Basidiomycota, two to Mucoromycota and two were fungal-like organisms. The nuc rDNA V1-V5 regions of 18S (18S) and D1-D3 regions of 28S (28S) were sequenced from representative isolates of each OTU for comparison to GenBank sequences. Isolates of Lulworthiales and Eurotiales were the most abundant, with seven isolates each. Among the 22 OTUs, nine represent potentially undescribed species based on low similarity to GenBank sequences and 10 isolates showed inhibitory activity against Gram-positive bacteria in an agar diffusion plug assay. These results show promise for the Arctic region as asource of novel marine fungi with the ability to produce bioactive secondary metabolites with antibacterial properties.

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Section: Discussionsupporting

confidence: 76%

Cultivable marine fungi from the Arctic Archipelago of Svalbard and their antibacterial activity

et al. 2019

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“…It can be argued that “marine-derived” fungi are a proven source of new natural products; this is not in dispute as over a thousand new compounds or new derivatives of known molecules have been discovered over the past few decades. However, recent evidence has demonstrated that the new chemistry is a result of saline stress, where terrestrial counterparts of the same species produce the same chemistry as discovered from marine-derived strains when grown on media containing seawater [70]. Simply mining the terrestrial isolates of osmotolerant species on media containing seawater will achieve the same ends.…”

Section: Discussionmentioning

confidence: 99%

The Neglected Marine Fungi, Sensu stricto, and Their Isolation for Natural Products’ Discovery

et al. 2019

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Despite the rapid development of molecular techniques relevant for natural product research, culture isolates remain the primary source from which natural products chemists discover and obtain new molecules from microbial sources. Techniques for obtaining and identifying microbial isolates (such as filamentous fungi) are thus of crucial importance for a successful natural products’ discovery program. This review is presented as a “best-practices guide” to the collection and isolation of marine fungi for natural products research. Many of these practices are proven techniques used by mycologists for the isolation of a broad diversity of fungi, while others, such as the construction of marine baiting stations and the collection and processing of sea foam using dilution to extinction plating techniques, are methodological adaptations for specialized use in marine/aquatic environments. To this day, marine fungi, Sensu stricto, remain one of the few underexplored resources of natural products. Cultivability is one of the main limitations hindering the discovery of natural products from marine fungi. Through encouraged collaboration with marine mycologists and the sharing of historically proven mycological practices for the isolation of marine fungi, our goal is to provide natural products chemists with the necessary tools to explore this resource in-depth and discover new and potentially novel natural products.

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“…Overy and colleagues investigated the effects of osmolarity and salinity on the production of SMs in the terrestrial halophilic fungus, Aspergillus aculeatus [ 86 ]. They found that SMs such as aspergillusol, secalonic acid D, aculene C and another aculene analog were up-regulated in the fungus under saline conditions; with production of aspergillusol in particular being associated with a halotolerant response to saline conditions involving seawater/sea salts.…”

Section: Change In Physical Parametersmentioning

confidence: 99%

Extending the “One Strain Many Compounds” (OSMAC) Principle to Marine Microorganisms

et al. 2018

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Genomic data often highlights an inconsistency between the number of gene clusters identified using bioinformatic approaches as potentially producing secondary metabolites and the actual number of chemically characterized secondary metabolites produced by any given microorganism. Such gene clusters are generally considered as “silent”, meaning that they are not expressed under laboratory conditions. Triggering expression of these “silent” clusters could result in unlocking the chemical diversity they control, allowing the discovery of novel molecules of both medical and biotechnological interest. Therefore, both genetic and cultivation-based techniques have been developed aimed at stimulating expression of these “silent” genes. The principles behind the cultivation based approaches have been conceptualized in the “one strain many compounds” (OSMAC) framework, which underlines how a single strain can produce different molecules when grown under different environmental conditions. Parameters such as, nutrient content, temperature, and rate of aeration can be easily changed, altering the global physiology of a microbial strain and in turn significantly affecting its secondary metabolism. As a direct extension of such approaches, co-cultivation strategies and the addition of chemical elicitors have also been used as cues to activate “silent” clusters. In this review, we aim to provide a focused and comprehensive overview of these strategies as they pertain to marine microbes. Moreover, we underline how changes in some parameters which have provided important results in terrestrial microbes, but which have rarely been considered in marine microorganisms, may represent additional strategies to awaken “silent” gene clusters in marine microbes. Unfortunately, the empirical nature of the OSMAC approach forces scientists to perform extensive laboratory experiments. Nevertheless, we believe that some computation and experimental based techniques which are used in other disciplines, and which we discuss; could be effectively employed to help streamline the OSMAC based approaches. We believe that natural products discovery in marine microorganisms would be greatly aided through the integration of basic microbiological approaches, computational methods, and technological innovations, thereby helping unearth much of the as yet untapped potential of these microorganisms.

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Does Osmotic Stress Affect Natural Product Expression in Fungi?

Cited by 40 publications

References 41 publications

Cultivable marine fungi from the Arctic Archipelago of Svalbard and their antibacterial activity

Cultivable marine fungi from the Arctic Archipelago of Svalbard and their antibacterial activity

The Neglected Marine Fungi, Sensu stricto, and Their Isolation for Natural Products’ Discovery

Extending the “One Strain Many Compounds” (OSMAC) Principle to Marine Microorganisms

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