The Madeira Archipelago As a Significant Source of Marine-Derived Actinomycete Diversity with Anticancer and Antimicrobial Potential

Abstract

Marine-derived actinomycetes have demonstrated an ability to produce novel compounds with medically relevant biological activity. Studying the diversity and biogeographical patterns of marine actinomycetes offers an opportunity to identify genera that are under environmental pressures, which may drive adaptations that yield specific biosynthetic capabilities. The present study describes research efforts to explore regions of the Atlantic Ocean, specifically around the Madeira Archipelago, where knowledge of the indigenous actinomycete diversity is scarce. A total of 400 actinomycetes were isolated, sequenced, and screened for antimicrobial and anticancer activities. The three most abundant genera identified were Streptomyces, Actinomadura, and Micromonospora. Phylogenetic analyses of the marine OTUs isolated indicated that the Madeira Archipelago is a new source of actinomycetes adapted to life in the ocean. Phylogenetic differences between offshore (>100 m from shore) and nearshore (< 100 m from shore) populations illustrates the importance of sampling offshore in order to isolate new and diverse bacterial strains. Novel phylotypes from chemically rich marine actinomycete groups like MAR4 and the genus Salinispora were isolated. Anticancer and antimicrobial assays identified Streptomyces, Micromonospora, and Salinispora as the most biologically active genera. This study illustrates the importance of bioprospecting efforts at unexplored regions of the ocean to recover bacterial strains with the potential to produce novel and interesting chemistry.

Intra‐clade metabolomic profiling of MAR4 Streptomyces from the Macaronesia Atlantic region reveals a source of anti‐biofilm metabolites

“…To assess the metabolomic diversity of the Macaronesia MAR4 lineage, six strains from this clade, previously isolated from marine sediment samples collected off the Madeira Archipelago (Prieto‐Davó et al ., ) (Supporting Information Table S1), were investigated for their ability to produce biologically active metabolites and for their differences in secondary metabolite content both by chromatographic profiling, multivariate analyses and MS/MS‐based molecular networking (Moree et al ., ; Wang et al ., ). A multivariate statistical analysis (PLS‐DA), which correlated the metabolomics results and anti‐biofilm activity assays, was used to determine the class of bioactive metabolites with anti‐biofilm activity.…”

“…S. xinghaiensis was used as reference to show the MAR4 grouping within Streptomyces and Micromonospora sagamiensis was used as outgroup. Sequences were aligned using ClustalX and the alignment used to create a maximum likelihood phylogenetic tree of 1279 bp using MEGA with 1000 bootstraps (Prieto‐Davó et al ., ). [Color figure can be viewed at wileyonlinelibrary.com]…”

“…Phylogenetically, PTM-346 is the closest strain to S. aculeolatus species ( Fig. 3) (Prieto-Davó et al, 2016), while it is chemically closer to S. synnematoformans. Thus, our results support that the production of hybrid isoprenoids is a phenotypic trait that differentiates the two MAR4 clades (Gallagher et al, 2013).…”

“…Based on 16S rRNA gene sequence 99% phylogenetic similarity to the MAR4 Streptomycete lineage, six strains of Streptomyces isolated from marine-sediments from the Madeira Archipelago were selected from a previously reported actinomycete culture collection stored at −80 C (Prieto-Davó et al, 2016).…”

“…at 25 C for 7 days. The 25 ml culture were then inoculated into 5 l of M1 medium and fermented under the same conditions (Prieto-Davó et al, 2016). The culture broth was extracted with EtOAc.…”