Extracellular Vesicles from marine microorganisms

Abstract

It is well-known that cells of all domains of life produce extracellular vesicles (EVs). In microorganisms vesicles are produced when small regions of the outer membrane bulge before pinching off and being released from the cell. These EVs can perform a variety of functions, including binding and delivery of DNA, transport of virulence factors, protection of the cell from outer membrane targeting antimicrobials and ridding the cell of toxic envelope proteins. Recently a lot of studies have been done to understand the function of EVs, however, EVs from marine microorganisms have been seldom studied and hence in this presentation various features of them are reported.A hyperthermophilic archaeon, Thermococcus onnurineus, produced spherical EVs of which the size ranged between 80 and 250 nm in diameter and contained DNA, RNA, proteins and other molecules which were derived from the parental cells. According to the genomic analysis of EVs from Thermococcus onnurineus (ToEVs) almost all chromosomal genome of parental cells was packaged into ToEVs, however, a certain part was never found from the ToEVs genome sequences. Comparative proteome analysis between ToEVs and parental cells indicated several proteins including ABC-type transport system component closely related with vesicle formation were preferentially packaged into vesicles. EVs of a marine Flavobacterium contained the membrane bound pigments like carotenoid and PR, and showed proton pumping activity like the parental cells. These photo-proteins of EVs generated the proton motive force which can be utilized for the ATP synthesis. These results imply vesicles produce energy for which is required for the certain period in natural environment. On the basis of these findings, microorganisms might be able to influence the others or to survive themselves in harsh marine environments by deliver diverse molecules into vesicles as discrete packages.