Metabolites of bacteria isolated from marine environments: chemistry and bioactivities

Abstract

Roseovarius oyster disease (ROD) is a bacterial-induced infection and causes major problems in oyster aquaculture. Bacteria of the genus Labrenzia have been proposed as protective agents against ROD. The here investigated Labrenzia sp. 011 was found to produce two cyclopropane-containing medium-chain fatty acids (1, 2). Compounds 1 and 2 inhibit the growth of a range of bacteria and fungi, most effectively that of the causative agent of ROD, Pseudoroseovarius crassostreae DSM 16950. The genome of Labrenzia sp. 011 was sequenced and bioinformatically compared with that of other Labrenzia spp. This analysis revealed several cyclopropane fatty acid synthases (CFAS) conserved in all Labrenzia strains analyzed, and a putative gene cluster encoding for two distinct CFASs is proposed as the biosynthetic origin of 1 and 2. Compound 2 was found to act as a potent partial, beta-arrestin-biased agonist at the medium chain fatty acid-activated orphan G protein-coupled receptor GPR84, which is highly expressed on immune cells.