Contribution of vesicle-protected extracellular DNA to horizontal gene transfer in Thermus spp. Authors Alba Blesa Center of Molecular Biology Severo Ochoa, Autonomous University of Madrid-CSIC, Madrid, Spain José Berenguer Center of Molecular Biology Severo Ochoa, Autonomous University of Madrid-CSIC, Madrid, Spain Keywords: Thermus, horizontal gene transfer, extracellular vesicles Abstract Highly efficient apparatus for natural competence and conjugation have been shown as the major contributors to horizontal gene transfer (HGT) in Thermus thermophilus. In practical terms, both mechanisms can be distinguished by the sensitivity of the former to the presence of DNAse, and the requirement for cell to cell contacts in the second. Here we demonstrate that culture supernatants of different strains of Thermus spp. produce DNAse-resistant extracellular DNA (eDNA) in a growth-rate dependent manner. This eDNA was double stranded, similar in size to isolated genomic DNA (around 20 kbp), and represented the whole genome of the producer strain. Protection against DNAse was the consequence of association of the eDNA to membrane vesicles which composition was shown to include a great diversity of cell envelope proteins with minor content of cytoplasmic proteins. Access of the recipient cell to the protected eDNA depended on the natural competence apparatus and elicited the DNA–DNA interference defence mediated by the Argonaute protein. We hypothesize on the lytic origin of the eDNA carrying vesicles and discuss the relevance of this alternative mechanism for HGT in natural thermal environments. [Int Microbiol 18(3):177-187 (2015)]Keywords: Thermus · horizontal gene transfer · extracellular vesicles Downloads PDF Issue Vol. 18 No. 3 (2015) Section Research Articles License Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. The corresponding author signs for and accepts responsability for releasing this material and will act on behalf of any and all coauthors regarding the editorial review and publication process.If an article is accepted for publication in International Microbiology, the authors (or other copyright holder) must transfer to the journal the right–not exclusive–to reproduce and distribute the article including reprints, translations, photographic reproductions, microform, electronic form (offline, online) or any other reproductions of similar nature. Nevertheless, all article in International Microbiology will be available on the Internet to any reader at no cost. The journal allows users to freely download, copy, print, distribute, search, and link to the full text of any article, provided the authorship and source of the published article is cited. The copyright owner's consent does not include copying for new works, or resale. In these cases, the specific written permission of International Microbiology must first be obtained.Authors are requested to create a link to the published article on the journal's website. The link must be accompanied by the following text: "The original publication is available on LINK at <http://www.im.microbios.org>. Please use the appropiate URL for the article in LINK. Articles disseminated via LINK are indexed, abstracted, and referenced by many abstracting and information services, bibliographic networks, subscription agencies, library networks, and consortia.
