Bioactive Secondary Metabolites from Octocoral-Associated Microbes—New Chances for Blue Growth

Abstract

Octocorals (Cnidaria, Anthozoa Octocorallia) are magnificent repositories of natural products with fascinating and unusual chemical structures and bioactivities of interest to medicine and biotechnology. However, mechanistic understanding of the contribution of microbial symbionts to the chemical diversity of octocorals is yet to be achieved. This review inventories the natural products so-far described for octocoral-derived bacteria and fungi, uncovering a true chemical arsenal of terpenes, steroids, alkaloids, and polyketides with antibacterial, antifungal, antiviral, antifouling, anticancer, anti-inflammatory, and antimalarial activities of enormous potential for blue growth. Genome mining of 15 bacterial associates (spanning 12 genera) cultivated from Eunicella spp. resulted in the identification of 440 putative and classifiable secondary metabolite biosynthetic gene clusters (BGCs), encompassing varied terpene-, polyketide-, bacteriocin-, and nonribosomal peptide-synthase BGCs. This points towards a widespread yet uncharted capacity of octocoral-associated bacteria to synthetize a broad range of natural products. However, to extend our knowledge and foster the near-future laboratory production of bioactive compounds from (cultivatable and currently uncultivatable) octocoral symbionts, optimal blending between targeted metagenomics, DNA recombinant technologies, improved symbiont cultivation, functional genomics, and analytical chemistry are required. Such a multidisciplinary undertaking is key to achieving a sustainable response to the urgent industrial demand for novel drugs and enzyme varieties.

Comparative genomics reveals complex natural product biosynthesis capacities and carbon metabolism across host‐associated and free‐living Aquimarina (Bacteroidetes, Flavobacteriaceae) species

“…Natural products and natural product‐derived small molecules are still the most important source and inspiration for modern chemotherapeutics. One of the most preeminent ecosystems as a reservoir of new compounds is the marine environment where bacteria, often associated with eukaryotic hosts such as sponges, corals and algae, usually display a striking secondary metabolism (Raimundo et al ., ). In this context, this study showcases unprecedented, intriguing biosynthetic potential for the Aquimarina genus, highlighting its likely use as a future source of biotechnological appliances and widening the natural product coding spectrum of the Bacteroidetes , a quintessential bacterial phylum in marine ecosystems.…”

“…Given its recent structural elucidation and purification in the laboratory, it is likely that bioactivities for cuniculene and structurally related compounds will soon be revealed. As polyketides, NRPs are of utmost interest for the field of drug discovery and their potential biosynthesis has been often reported from symbiotic microbial communities (Agrawal et al, 2016;Raimundo et al, 2018). Among NRPs are more than 20 marketed drugs with antimicrobial, antitumoural and immunosuppressant activity (Sussmuth and Mainz, 2017), encouraging further studies of compounds from diverse microorganisms and isolation sources.…”

The Biotechnological Potential of Secondary Metabolites from Marine Bacteria

“…The thiopeptide antibiotic TP-1161, isolated from the marine Gram-positive bacterium Nocardiopsis sp., belongs to the same structural group [36][37][38]. This antibiotic showed high antibacterial activity in vitro against clinical isolates of Gram-positive bacteria (with MIC varying from 0.25 to 4 µg/mL), i.e., at concentrations comparable or lower than that of the reference antibiotic vancomycin.…”

The Biological and Chemical Diversity of Tetramic Acid Compounds from Marine-Derived Microorganisms

“…Marine natural products (MNPs) are considered an unexploited treasure trove of new bioactive NPs for the 21st century. Among them, marine microorganism-derived NPs have become the primary source of new MNPs, from less than 20% of newly discovered MNPs in 2006 to 57% in 2017 (based on a summary of a series of reviews "Marine Natural Products" published by Blunt and his colleagues during 2008-2019 [10,11]. While there have been no special reviews about tetramic acid compounds from marine microbes, especially in the past six years, numerous examples of new tetramate molecules from colleagues during 2008-2019 [10,11].…”