Biodiversity of Actinobacteria from the South Pacific and the Assessment of Streptomyces Chemical Diversity with Metabolic Profiling

Abstract

Recently, bioprospecting in underexplored habitats has gained enhanced focus, since new taxa of marine actinobacteria can be found, and thus possible new metabolites. Actinobacteria are in the foreground due to their versatile production of secondary metabolites that present various biological activities, such as antibacterials, antitumorals and antifungals. Chilean marine ecosystems remain largely unexplored and may represent an important source for the discovery of bioactive compounds. Various culture conditions to enrich the growth of this phylum were used and 232 bacterial strains were isolated. Comparative analysis of the 16S rRNA gene sequences led to identifying genetic affiliations of 32 genera, belonging to 20 families. This study shows a remarkable culturable diversity of actinobacteria, associated to marine environments along Chile. Furthermore, 30 streptomycete strains were studied to establish their antibacterial activities against five model strains, Staphylococcus aureus, Listeria monocytogenes, Salmonella enterica, Escherichia coli and Pseudomonas aeruginosa, demonstrating abilities to inhibit bacterial growth of Gram-positive bacteria. To gain insight into their metabolic profiles, crude extracts were submitted to liquid chromatography-high resolution mass spectrometry (LC-HRMS) analysis to assess the selection of streptomycete strains with potentials of producing novel bioactive metabolites. The combined approach allowed for the identification of three streptomycete strains to pursue further investigations. Our Chilean marine actinobacterial culture collection represents an important resource for the bioprospection of novel marine actinomycetes and its metabolites, evidencing their potential as producers of natural bioproducts.

Marine Rare Actinomycetes: A Promising Source of Structurally Diverse and Unique Novel Natural Products

“…Marine habitats are also a rich source of diverse and largely uncharacterized microbial communities including actinomycetes [62]. This habitat shows extreme variations in ecological pressure, including competition for space, predation, available nutrients, light, oxygen concentration and pressure.…”

“…A substantial number of rare actinomycetes were reported to be associated to various members of marine benthic communities, such as sponges, corals, ascidians, sea anemones, sea cucumbers, sea urchins and seaweeds [7,62,81]. Five novel genera, 17 new rare actinomycete species belonging to 11 different actinomycete families were reported from marine plants and animals between 2007 and mid-2013 [7].…”

Genomic Variation and Arsenic Tolerance Emerged as Niche Specific Adaptations by Different Exiguobacterium Strains Isolated From the Extreme Salar de Huasco Environment in Chilean – Altiplano

“…We set up to pick the characteristic orange pigmented colonies and also through microscopy we selected the Gram-positive rods. Besides, we also included seven other previously isolated strains, five from Easter island (Chile) (Cumsille et al, 2017), which were provided by Dra. Beatriz Cámara from Universidad Técnica Federico Santa María (Valparaíso, Chile).…”

Isolation and Identification of Streptomyces spp. from Desert and Savanna Soils in Sudan

“…Exploring new habitats around the globe is increasingly becoming the focus for discovering new taxa of Actinobacteria, namely streptomycetes, for potential antibacterial, antitumoral, and antifungal activities [ 7 , 8 ]. The habitat of Sudan has remained virtually untouched except for very few studies.…”