Biotechnological potential of Actinobacteria from Canadian and Azorean volcanic caves

Abstract

Caves are regarded as extreme habitats with appropriate conditions for the development of Actinobacteria. In comparison with other habitats, caves have not yet been the target of intensive screening for bioactive secondary metabolites produced by actinomycetes. As a primary screening strategy, we conducted a metagenomic analysis of the diversity and richness of a key gene required for non-ribosomal peptide (NRP) biosynthesis, focusing on cave-derived sediments from two Canadian caves (a lava tube and a limestone cave) to help us predict whether different types of caves may harbor drug-producing actinobacteria. Using degenerate PCR primers targeting adenylation domains (AD), a conserved domain in the core gene in NRP biosynthesis, a number of amplicons were obtained that mapped back to biomedically relevant NRP gene cluster families. This result guided our culture-dependent sampling strategy of actinomycete isolation from the volcanic caves of Canada (British Columbia) and Portugal (Azores) and subsequent characterization of their antibacterial and enzymatic activities. Multiple enzymatic and antimicrobial activities were identified from bacterial of the Arthrobacter and Streptomyces genera demonstrating that actinomycetes from volcanic caves are promising sources of antibacterial, antibiofilm compounds and industrially relevant enzymes.

In Situ Cultured Bacterial Diversity from Iron Curtain Cave, Chilliwack, British Columbia, Canada

“…(3.44%) were also recognized in our study. A study from Riquelme et al 2017 has reported the presence of these genera in the Canadian and Azorean volcanic cave [24]. However, a study from Jurado et al 2010 designated both Rhodococcus spp.…”

“…as the second largest class (13.79%) in the Actinobacterial phylum. However, most of the previous microbial diversity studies both from Karstic and volcanic caves identified Streptomyces as the major bacterial class [22,24,25]. Rhodococcus spp.…”

Cave Actinobacteria as Producers of Bioactive Metabolites

“…Isolation of actinobacteria from unique natural habitats is of interest to avoid re-isolation of strains that produce known bioactive metabolites and usually lead to highly diverse actinobacterial communities. The present mini-review provides evidence that actinobacteria from caves are expected to be a good source for drug discovery (Yücel and Yamac, 2010; Cheeptham et al, 2013; Kay et al, 2013; Ghosh et al, 2017; Riquelme et al, 2017).…”

“…avidinii , and S . mauvecolor ) followed by Arthrobacter (Riquelme et al, 2017). A total of 40 taxa belonging to the genera Agromyces, Amycolatopsis, Kocuria, Micrococcus, Micromonospora, Nocardia, Streptomyces , and Rhodococcus were recovered from moonmilk deposits inside the Grotte des Collemboles, Belgium.…”

Estimation of antimicrobial activities and fatty acid composition of actinobacteria isolated from water surface of underground lakes from Badzheyskaya and Okhotnichya caves in Siberia

“…Members of this genus the Streptomyces genus are capable of using various mechanisms of competition including rapid limited-nutrient utilization combined with interference competition ( Vaz Jauri et al., 2013 ; Schlatter & Kinkel, 2014 ). Also, they produce most of antibiotics and natural products used in pharmacy and medicine ( Goodfellow & Fiedler, 2010 ; Bérdy, 2012 ; Riquelme et al, 2017 ).…”