Diversity and Biosynthetic Potential of Culturable Actinomycetes Associated with Marine Sponges in the China Seas

Abstract

The diversity and secondary metabolite potential of culturable actinomycetes associated with eight different marine sponges collected from the South China Sea and the Yellow sea were investigated. A total of 327 strains were isolated and 108 representative isolates were selected for phylogenetic analysis. Ten families and 13 genera of Actinomycetales were detected, among which five genera represent first records isolated from marine sponges. Oligotrophic medium M5 (water agar) proved to be efficient for selective isolation, and “Micromonospora–Streptomyces” was proposed as the major distribution group of sponge-associated actinomycetes from the China Seas. Ten isolates are likely to represent novel species. Sponge Hymeniacidon perleve was found to contain the highest genus diversity (seven genera) of actinomycetes. Housekeeping gene phylogenetic analyses of the isolates indicated one ubiquitous Micromonospora species, one unique Streptomyces species and one unique Verrucosispora phylogroup. Of the isolates, 27.5% displayed antimicrobial activity, and 91% contained polyketide synthase and/or nonribosomal peptide synthetase genes, indicating that these isolates had a high potential to produce secondary metabolites. The isolates from sponge Axinella sp. contained the highest presence of both antimicrobial activity and NRPS genes, while those from isolation medium DNBA showed the highest presence of antimicrobial activity and PKS I genes.

Oligotrophy is Helpful for the Isolation of Bioactive Actinomycetes

“…This could be helpful for the discovery of new antibiotic producers and the exploitation and utilization of new, biologically active compounds. Previous researches had proved that oligotrophic media could positively influence the isolation of actinomycetes [10,11]. While no research have made systematic comparison between standard medium and the corresponding oligotrophic medium to study the specific effect of oligotrophy on actinomycetes isolation, which was studied in this research.…”

“…However, oligotrophic media prevent the overgrowth of eutrophic and fast-growing actinomycetes, which provide oligotrophic actinomycetes with suitable nutrients concentration and sufficient growing space. Previous researches indicated that oligotrophy is an important way to explore unknown actinomycete resources [10,11]. We should pay more attention to the comprehensive study of the improving effects of oligotrophy on the actinomycetes isolation.…”

Streptomyces ansochromogenes Tur-10 produces a substance with antifungal bioactivity

“…However, there are still few studies involving the search for these genes in actinobacteria. Xi et al (2012) estimated that 27.5% of the isolates tested that belonged to the genus Streptomyces (34 isolates) showed antimicrobial activity, and it has been shown that the strains where both pks and nrps genes were identified produced a significantly higher number of secondary metabolites. Zhong et al (2013) demonstrated the assembly and features of secondary metabolite biosynthetic gene clusters with pks and nrps in S. ansochromogenes.…”

Molecules to Ecosystems: Actinomycete Natural Products In situ

“…Comprehensive laboratory analyses done on sponge associated actinomycetes has found that a number of different species are culturable from marine sponges, and that they are capable of producing bioactive secondary metabolites (Schneemann et al, 2010; Xi et al, 2012). With respect to the sponge Halichondria panicea , for example, five actinomycete genera were isolated and the bacterial extracts were found to contain secondary metabolites with bioactivities (Schneemann et al, 2010).…”