{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T23:50:11Z","timestamp":1792194611625,"version":"4.4.0"},"reference-count":21,"publisher":"National Academy of Sciences","issue":"36","license":[{"start":{"date-parts":[[2022,8,29]],"date-time":"2022-08-29T00:00:00Z","timestamp":1661731200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002428","name":"Austrian Science Fund","doi-asserted-by":"publisher","award":["DOC 69-B"],"award-info":[{"award-number":["DOC 69-B"]}],"id":[{"id":"10.13039\/501100002428","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100018694","name":"EC | Horizon Europe | Excellent Science | HORIZON EUROPE Marie Sklodowska-Curie Actions","doi-asserted-by":"publisher","award":["891572"],"award-info":[{"award-number":["891572"]}],"id":[{"id":"10.13039\/100018694","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2022,9,6]]},"abstract":"<jats:p>\n                    Protists are important regulators of microbial communities and key components in food webs with impact on nutrient cycling and ecosystem functioning. In turn, their activity is shaped by diverse intracellular parasites, including bacterial symbionts and viruses. Yet, bacteria\u2013virus interactions within protists are poorly understood. Here, we studied the role of bacterial symbionts of free-living amoebae in the establishment of infections with nucleocytoplasmic large DNA viruses (Nucleocytoviricota). To investigate these interactions in a system that would also be relevant in nature, we first isolated and characterized a giant virus (Viennavirus, family Marseilleviridae) and a sympatric potential\n                    <jats:italic>Acanthamoeba<\/jats:italic>\n                    host infected with bacterial symbionts. Subsequently, coinfection experiments were carried out, using the fresh environmental isolates as well as additional amoeba laboratory strains. Employing fluorescence in situ hybridization and qPCR, we show that the bacterial symbiont, identified as\n                    <jats:italic>Parachlamydia acanthamoebae<\/jats:italic>\n                    , represses the replication of the sympatric Viennavirus in both recent environmental isolates as well as\n                    <jats:italic>Acanthamoeba<\/jats:italic>\n                    laboratory strains. In the presence of the symbiont, virions are still taken up, but viral factory maturation is inhibited, leading to survival of the amoeba host. The symbiont also suppressed the replication of the more complex\n                    <jats:italic>Acanthamoeba polyphaga mimivirus<\/jats:italic>\n                    and\n                    <jats:italic>Tupanvirus deep ocean<\/jats:italic>\n                    (Mimiviridae). Our work provides an example of an intracellular bacterial symbiont protecting a protist host against virus infections. The impact of virus\u2013symbiont interactions on microbial population dynamics and eventually ecosystem processes requires further attention.\n                  <\/jats:p>","DOI":"10.1073\/pnas.2205856119","type":"journal-article","created":{"date-parts":[[2022,8,29]],"date-time":"2022-08-29T15:13:40Z","timestamp":1661786020000},"update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":42,"title":["Defensive symbiosis against giant viruses in amoebae"],"prefix":"10.1073","volume":"119","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6712-1649","authenticated-orcid":false,"given":"Patrick","family":"Arthofer","sequence":"first","affiliation":[{"name":"Centre for Microbiology and Environmental Systems Science, University of Vienna, 1030 Vienna, Austria"},{"name":"Doctoral School in Microbiology and Environmental Science, University of Vienna, 1030 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1111-2916","authenticated-orcid":false,"given":"Vincent","family":"Delafont","sequence":"additional","affiliation":[{"name":"Ecologie et Biologie des Interactions Laboratory, UMR CNRS, Universit\u00e9 de Poitiers, 7267 Poitiers, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8511-3244","authenticated-orcid":false,"given":"Anouk","family":"Willemsen","sequence":"additional","affiliation":[{"name":"Centre for Microbiology and Environmental Systems Science, University of Vienna, 1030 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Florian","family":"Panh\u00f6lzl","sequence":"additional","affiliation":[{"name":"Centre for Microbiology and Environmental Systems Science, University of Vienna, 1030 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8309-5855","authenticated-orcid":false,"given":"Matthias","family":"Horn","sequence":"additional","affiliation":[{"name":"Centre for Microbiology and Environmental Systems Science, University of Vienna, 1030 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2022,8,29]]},"reference":[{"key":"e_1_3_4_1_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cub.2021.07.066"},{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1038\/21119"},{"key":"e_1_3_4_3_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.1081867"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0911354106"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.1239181"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1038\/nature20593"},{"key":"e_1_3_4_7_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-018-03168-1"},{"key":"e_1_3_4_8_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.coviro.2013.07.003"},{"key":"e_1_3_4_9_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.micinf.2017.12.012"},{"key":"e_1_3_4_10_2","doi-asserted-by":"publisher","DOI":"10.1128\/mBio.00333-19"},{"key":"e_1_3_4_11_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cub.2021.05.049"},{"key":"e_1_3_4_12_2","doi-asserted-by":"publisher","DOI":"10.1093\/gbe\/evx074"},{"key":"e_1_3_4_13_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.aal4657"},{"key":"e_1_3_4_14_2","doi-asserted-by":"publisher","DOI":"10.3389\/fmicb.2021.648731"},{"key":"e_1_3_4_15_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.tim.2020.05.020"},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.1111\/1574-6976.12059"},{"key":"e_1_3_4_17_2","doi-asserted-by":"publisher","DOI":"10.1128\/JVI.00177-16"},{"key":"e_1_3_4_18_2","doi-asserted-by":"publisher","DOI":"10.1038\/nrmicro.2016.30"},{"key":"e_1_3_4_19_2","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.micro.62.081307.162818"},{"key":"e_1_3_4_20_2","doi-asserted-by":"publisher","DOI":"10.1186\/s12985-019-1244-3"},{"key":"e_1_3_4_21_2","unstructured":"P. Arthofer V. Delafont A. Willemsen F. Panh\u00f6lzl M. Horn A bacterial symbiont represses replication of giant viruses in amoebae. BioProject. http:\/\/www.ncbi.nlm.nih.gov\/bioproject?term=PRJNA799241. Deposited 21 January 2022."}],"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.2205856119","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,8,29]],"date-time":"2022-08-29T15:18:44Z","timestamp":1661786324000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.2205856119"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,8,29]]},"references-count":21,"journal-issue":{"issue":"36","published-print":{"date-parts":[[2022,9,6]]}},"alternative-id":["10.1073\/pnas.2205856119"],"URL":"https:\/\/doi.org\/10.1073\/pnas.2205856119","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,8,29]]},"assertion":[{"value":"2022-05-10","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2022-06-19","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2022-08-29","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e2205856119"}}