Structural diversity and possible functional roles of free fatty acids of the novel soil isolate Streptomyces sp. NP10

Abstract

Herein, a novel soil bacterium Streptomyces sp. NP10 able to grow outside usual streptomycetes optimum conditions (e.g., at 4 °C, pH 9 and high NaCl concentration), exhibiting atypical hemolytic, DNAse, and cellulolytic activities, is described. This strain produces and excretes into the growth medium large amounts of free long-chain fatty acids (FAs). A concurrent lipidomics study revealed a large structural diversity of FAs with over 50 different n- and branched-chain, (un)saturated, and cyclopropane FAs (C7-C30) produced by this strain. Two of these, i-17:0cy9-10 and a-18:0cy9-10, represent new natural products and the first ever identified branched cyclopropane FAs. Both free and bound lipid profiles of Streptomyces sp. NP10 were dominated by saturated branched chain FAs (i-14:0, a-15:0, and i-16:0). Although these free FAs showed only a moderate antimicrobial activity, our results suggest that they could have an ecophysiological role in interspecies signaling with another soil microorganism Pseudomonas aeruginosa. This work represents the first comprehensive report on the structural diversity and complexity of the free FA pool in Streptomyces. A naturally occurring streptomycete, such as Streptomyces sp. NP10, which secretes significant amounts of free long-chain FAs (non-cytotoxic) into the medium, could be useful in microbial biodiesel production.

Diethyl‐Ether Flower Washings of Dianthus cruentusGriseb. (Caryophyllaceae): Derivatization Reactions Leading to the Identification of New Wax Constituents

“…The identification of these methyl esters was based on an analysis of their mass spectra and the comparison of the obtained RI data with the previously published ones for lower homologs from the series of n-, iso-and/or anteiso-long-chain fatty acids methyl esters. [16] Thus, in this way we proved the presence of hexyl esters of the above-mentioned branched iso-or anteiso-fatty acids (C 22 À C 31 ; Table 1) in the washings. Based on a detailed literature survey (Table S1), all identified hexyl esters of iso-or anteisofatty acids (8 constituents in total) represent new compounds and newly discovered natural products (Figure 1).…”

C. elegans avoids toxin-producing Streptomyces using a seven transmembrane domain chemosensory receptor

“…Both SDS and these carboxylic acids have long hydrophobic alkyl tails and negatively charged head groups at pH 7. Interestingly, the NP10 strain of Streptomyces ( Figure 1A ) secretes carboxylic acids that have these characteristics ( Ilic-Tomic et al, 2015 ). We therefore used the tail drop assay to test a series of carboxylic acids of varying chain lengths, with and without cis double-bonds ( Figure 2C and Figure 2—figure supplement 1 ), to determine which, if any, C. elegans avoid.…”

Novel bioactive natural products from bacteria via bioprospecting, genome mining and metabolic engineering

“…Recently, Streptomyces sp. NP10 strain was isolated, which is characterized by unusually high production of free fatty acids (FAs) (Ilic‐Tomic et al ., ). A lipidomics study on this strain revealed a large structural diversity of produced FAs with over 50 different n and branched chain, (un)saturated and cyclopropane FAs (C 7 –C 30 ).…”

“…A lipidomics study on this strain revealed a large structural diversity of produced FAs with over 50 different n and branched chain, (un)saturated and cyclopropane FAs (C 7 –C 30 ). Two of these, i ‐17:0cy9‐10 and a ‐18:0cy9‐10, represent new natural products (Ilic‐Tomic et al ., ). Based on the genome analysis of this strain coupled to gene inactivation, our group successfully identified a unique FA biosynthesis gene cluster responsible for this particular phenotype (Schneider et al ., ).…”