Streptomyces coelicolor Vesicles: Many Molecules To Be Delivered

Abstract

Streptomycetes are widely distributed in nature and characterized by a complex life cycle that involves morphological differentiation. They are very relevant in industry because they produce about half of all clinically used antibiotics, as well as other important pharmaceutical products of natural origin. Streptomyces coelicolor is a model organism for the study of bacterial differentiation and bioactive molecule production. S. coelicolor produces extracellular vesicles which carry many molecules, such as proteins and metabolites, including antibiotics.

Unravelling the DNA sequences carried by Streptomyces coelicolor membrane vesicles

“…Two main populations of MVs, namely F3 and F4 MVs, were isolated and purified from liquid cultures of S. coelicolor according to the protocol reported in Materials and Methods. These two MV populations were previously characterized: besides having different diameters (average sizes were about 100 nm and 200 nm in F3 and F4, respectively), they differed also for the composition of their protein and metabolite cargos 4 . All six gradient fraction were directly loaded on a 1% (w/v) agarose gel and this electrophoresis analysis revealed the presence of three main bands: two smaller bands corresponding to approximately 900 bp and 500 bp, respectively, and a higher molecular weight band of approximately 19 kb (Fig.…”

“…1 ). According to previous works, F3 and F4 were chosen for further investigations as they are the most MV-enriched gradient fractions 4 , 37 . Moreover, presence of MVs in F3 and F4 was confirmed through Dynamic Light Scattering (DLS) analysis (Supplementary Fig.…”

“…Bacterial membrane vesicles (MVs) are spherical and membranous particles with nanometer diameter and their cargo includes various macromolecules—such as nucleic acids (DNA and RNA), lipids, and proteins (i.e., enzymes and toxins)—and small molecules—such as cellular metabolites, signals, and bioactive molecules (i.e., antibiotics) 1 – 4 . The release of MVs can facilitate many biological functions such as nutrient uptake, competition, survival, stress response, intercellular communication, and horizontal gene transfer (HGT) 1 , 3 , 5 .…”

“…In recent years, Gram-positive MVs have gained more attention and their release was demonstrated in both pathogenic and non-pathogenic strains, such as Staphylococcus spp., Bacillus spp., Lactobacillus spp., and Streptomyces spp. 4 , 18 – 21 .…”

“…We have very recently demonstrated that S . coelicolor grown in liquid cultures releases MVs of different sizes and with specific protein and metabolic cargos 4 . However, it is not still clear whether specific DNA fragments or the entire set of Streptomyces genomic sequences can be carried by MVs.…”