A guide to successful bioprospecting: informed by actinobacterial systematics

Abstract

New structurally diverse natural products are discovered when novel screening procedures are introduced or when high quality biological materials from new sources are examined in existing screens, hence it is important to foster these two aspects of novelty in drug discovery programmes. Amongst prokaryotes, actinomycetes, notably streptomycetes, remain a rich source of new natural products though it has become increasingly difficult to find such metabolites from common actinomycetes as screening 'old friends' leads to the costly rediscovery of known compounds. The bioprospecting strategy which is the subject of this review is based upon the premise that new secondary metabolites can be found by screening relatively small numbers of dereplicated, novel actinomycetes isolated from marine sediments. The success of the strategy is exemplified by the discovery of a range of novel bioactive compounds, notably atrop-abyssomicin C and proximicins A, B and C from Verrucosispora strains isolated from sediment samples taken from the Sea of Japan and the Raune Fjord, respectively, and the dermacozines derived from Dermacoccus strains isolated from the Challenger Deep of the Mariana Trench in the Pacific Ocean. The importance of current advances in prokaryotic systematics in work of this nature is stressed and a plea made that resources be sought to train, support and employ the next generation of actinobacterial systematists.

Isolation and characterization of culturable endophytic actinobacteria associated with Artemisia annua L.

“…The discovery of candidate novel taxa shown in the present work supports the opinion of Strobel and Daisy (2003) that endophytes are a rich and reliable source of genetic diversity and novel as yet undescribed species. Actinobacteria are well known as a rich source of antimicrobial agents, and many useful antibiotics have been prepared from them (Goodfellow and Fiedler 2010). Many isolates obtained in this study showed antimicrobial, especially anti-phytopathogenic, activity in vitro.…”

Streptomyces actinomycinicus sp. nov., isolated from soil of a peat swamp forest

“…They contain LL-diaminopimelic acid in the cell-wall peptidoglycan and no diagnostic sugars in whole-cell hydrolysates (Kämpfer, 2012). Strains of species of the genus Streptomyces are the source of a broad range of secondary metabolites, notably antibiotics (Bérdy, 2005;Goodfellow & Fiedler, 2010), and are distributed in various environments including soils, freshwater and marine environments (Kämpfer, 2012).…”

Elaiomycins B and C, novel alkylhydrazides produced by Streptomyces sp. BK 190

“…2 Such organisms include neutrotolerant acidophilic streptomycetes which grow from pH 4.5 to 7.5, with an optimum between pH 5.0 and 5.5. 3 Members of this group were isolated from a hay meadow soil taken from Cockle Park Experimental Farm in Northumberland, UK.…”