[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-457636-105":59,"doc-detail-457636-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","ssdna-phage-flip-resides-in-dsdna-form-in-resistant-flavobacterium-host","ssDNA phage FLiP resides in dsDNA form in resistant Flavobacterium host","","Flavobacterium bacteria drive organic matter decomposition in aquatic environments, and their phages shape host populations and ecosystem functions. However, bacterial resistance to phage can alter phenotypes. This study examines how Flavobacterium strains resist the Finnlakevirus FLiP, a single-stranded DNA phage infecting isolates B330, B167, and B114. Fitness effects, genomic anti-phage screening, and lysogeny/superinfection analyses indicate resistance without detectable lab growth costs.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":40,"@type":76,"position":81},"https://docshare.wps.com/document/research-report/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/ssdna-phage-flip-resides-in-dsdna-form-in-resistant-flavobacterium-host/457636/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/ssdna-phage-flip-resides-in-dsdna-form-in-resistant-flavobacterium-host/457636.png","ImageObject",300,407,{"name":92,"@type":93},"Blue Pony","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-09","2026-09-30",true,{"@type":102,"interactionType":103,"userInteractionCount":39},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"Does resistance to FLiP affect bacterial fitness in laboratory conditions?","Question",{"text":112,"@type":113},"In the absence of phage, no significant differences in growth were observed between ancestral and resistant variants, indicating no detectable fitness cost under laboratory conditions.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"What genomic evidence was found for FLiP resistance?",{"text":117,"@type":113},"Host genome comparisons across strains and variants revealed resistance-related mutations, but no single mutation or anti-phage system consistently explained FLiP resistance across all strains.",{"name":119,"@type":110,"acceptedAnswer":120},"How is FLiP persistence in resistant hosts explained?",{"text":121,"@type":113},"In the resistant B114 host, the FLiP genome was detected as a circular extrachromosomal double-stranded DNA element, suggesting potential lysogeny, with low FLiP sequence levels also found in unexposed laboratory populations.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},457636,1791276356,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":39,"category_name":40,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":39,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":139,"language":140,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":141,"faqs":142,"seo_title":143,"seo_description":67,"update_tm":144,"read_time":145},962090760266,"https://ap-avatar.wpscdn.com/davatar_276721f389ce27ea32af1340a28f341c","Mäkelä et al. Biology Direct (2026) 21:2 [https://doi.org/10.1186/s13062-025-00708-w](https://doi.org/10.1186/s13062-025-00708-w)  \nBiology Direct  \nRESEARCH Open Access  \nssDNA phage FLiP resides in dsDNA form in resistant Flavobacterium host  \nKati Mäkelä 1, Reetta Penttinen 1, Janne Ravantti2, Elina Laanto 1 and Lotta-Riina Sundberg 1*  \nAbstract  \nBackground Bacteria in the genus Flavobacterium play a key role in organic matter decomposition in the aquatic environment. Phages infecting these bacteria regulate the host populations and thereby the ecosystem functions. However, bacterial resistance against phage may cause changes in bacterial phenotypic characteristics. The single stranded DNA phage Finnlakevirus FLiP infects three known environmental Flavobacterium sp. isolates: B330, B167, and B114 . Building on our previous FLiP-host interaction studies, we investigated resistance mechanisms from the host perspective, aiming to understand how Flavobacterium strains resist FLiP and related phages.  \nResults We assessed the fitness effects of phage resistance by comparing growth dynamics between ancestral and resistant variants. In the absence of phage, no significant differences in growth was observed, indicating that resistance to single stranded DNA phage FLiP does not impose a detectable fitness cost under laboratory conditions. Next, we screened host genomes for anti-phage systems and compared host genomes across strains and between ancestral and resistant variants. Genomic comparisons revealed resistance-related mutations, although no single mutation or anti-phage system consistently explained FLiP resistance across strains. Furthermore, we evaluated the possibility of lysogeny and superinfection immunity using sequence analysis, PCR, and nuclease treatments. Notably, resistant B114 host harbored the FLiP genome as a circular extrachromosomal double stranded DNA element, suggesting potential for lysogeny. Surprisingly, low levels of FLiP sequences were detected in bacterial populations not exposed to FLiP in the laboratory.  \nConclusions Our findings suggest that FLiP-type phages may persist in host populations as extrachromosomal double stranded DNA elements in a subset of cells. This strategy could allow phages to endure unfavorable conditions and regulate infection timing. As detected in previous experiments, rather than requiring optimal conditions, FLiP is capable of productive infection even under stress, with infection stalling only when host growthis severely limited. The constant persistence within the host population, and capability to start particle production as soon as conditions improve, may represent an evolutionary adaptation for survival and transmission in fluctuating environments.  \nKeywords ssDNA phage, Resistance, Lysogeny, Pseudolysogeny, Superinfection exclusion, Defence systems, Interactions  \n*Correspondence:  \nLotta-Riina Sundberg  \n[lotta-riina.sundberg@jyu.fi](lotta-riina.sundberg@jyu.fi)  \n1Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, P. O. Box 35, Jyväskylä FI-40014, Finland  \n2Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00014, Finland  \n© The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the mate","cbCaiombk3M074V4","https://ap.wps.com/l/cbCaiombk3M074V4","pdf",2343580,13,"English","# Background\n# Results\n## Fitness effects of phage resistance\n## Anti-phage system screening and genomic comparisons\n## Testing lysogeny and superinfection immunity\n# Conclusions\n# Keywords","[{\"question\":\"Does resistance to FLiP affect bacterial fitness in laboratory conditions?\",\"answer\":\"In the absence of phage, no significant differences in growth were observed between ancestral and resistant variants, indicating no detectable fitness cost under laboratory conditions.\"},{\"question\":\"What genomic evidence was found for FLiP resistance?\",\"answer\":\"Host genome comparisons across strains and variants revealed resistance-related mutations, but no single mutation or anti-phage system consistently explained FLiP resistance across all strains.\"},{\"question\":\"How is FLiP persistence in resistant hosts explained?\",\"answer\":\"In the resistant B114 host, the FLiP genome was detected as a circular extrachromosomal double-stranded DNA element, suggesting potential lysogeny, with low FLiP sequence levels also found in unexposed laboratory populations.\"}]","ssDNA phage FLiP resides in dsDNA form in resistant Flavobacterium host | PDF",1790750013,33]