{"id":13041,"date":"2025-06-25T08:35:07","date_gmt":"2025-06-25T08:35:07","guid":{"rendered":"https:\/\/www.europesays.com\/us\/13041\/"},"modified":"2025-06-25T08:35:07","modified_gmt":"2025-06-25T08:35:07","slug":"strange-cellular-entity-challenges-very-definition-of-life-itself-sciencealert","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/13041\/","title":{"rendered":"Strange Cellular Entity Challenges Very Definition of Life Itself : ScienceAlert"},"content":{"rendered":"

Within a tiny plankton, an even smaller cell has been found living an unexpectedly virus-like existence, challenging what it means to be alive<\/a>.<\/p>\n

The line between living and inanimate has traditionally and controversially<\/a> been drawn before viruses<\/a>, and the newly discovered organism, provisionally named Sukunaarchaeum mirabile, skates awfully close to it.<\/p>\n

Dalhousie University genomicist Ryo Harada and colleagues stumbled across the odd parasite while they were trying to catalog the DNA of the plankton species Citharistes regius and its symbiotic bacteria.<\/p>\n

A strange, tiny loop of DNA suggested the presence of another entity \u2013 one that didn’t neatly fit into known categories.<\/p>\n

“Sukunaarchaeum may represent the closest cellular entity discovered to date that approaches a viral strategy of existence,” the researchers write in their paper<\/a>.<\/p>\n

“This extreme specialization\u2026 challenges our fundamental understanding of the minimal requirements for cellular life.”<\/p>\n

Related: Hundreds of Mysterious Giant Viruses Discovered Lurking in The Ocean<\/a><\/strong><\/p>\n

Sukunaarchaeum only has 238,000 base pairs of DNA, yet some viruses reach 735,000 base pairs<\/a> or even 2.5 million<\/a>.<\/p>\n

Like viruses, Sukunaarchaeum delegates most of its biological functions, including metabolism, to its host. And also like viruses, most of the cell’s genes are dedicated to one thing: replicating itself.<\/p>\n

“Its genome is profoundly stripped-down, lacking virtually all recognizable metabolic pathways, and primarily encoding the machinery for its replicative core,” Harada and team explain<\/a>.<\/p>\n

“This suggests an unprecedented level of metabolic dependence on a host, a condition that challenges the functional distinctions between minimal cellular life and viruses.”<\/p>\n

\"TinyProperties of the newly discovered Sukunaarchaeum mirabile. (Harada et al., BioRxiv, 2025)<\/p>\n

Unlike viruses, however, Sukunaarchaeum still has the genes to create its own DNA replication proteins, including ribosomes, messenger RNA, and transfer RNA. Whereas, viruses hijack their hosts’ replication machinery.<\/p>\n

What’s more, Sukunaarchaeum produces proteins that are likely involved in forming a membrane to house its tiny circle of DNA, potentially helping with its interactions with its plankton host.<\/p>\n

Shared genes suggest Sukunaarchaeum belongs to archaea<\/a>, the domain of life from which our group, eukaryotes<\/a>, evolved. Its circular chromosome resembles the genetic material of bacteria and archaea.<\/p>\n

With no genes for metabolism, Sukunaarchaeum doesn’t appear to offer anything in return for the biological functions it commandeers from the plankton.<\/p>\n

Viruses are generally not considered alive<\/a> in part because they can’t replicate or sustain themselves without machinery provided by their host. Sukunaarchaeum can replicate, but not sustain itself, making that line between life and non-life even more precarious.<\/p>\n

This research has been uploaded onto bioRxiv<\/a> and has yet to be peer reviewed.<\/p>\n","protected":false},"excerpt":{"rendered":"Within a tiny plankton, an even smaller cell has been found living an unexpectedly virus-like existence, challenging what…\n","protected":false},"author":3,"featured_media":13042,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[352,159,67,132,68],"class_list":{"0":"post-13041","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-msft-content","9":"tag-science","10":"tag-united-states","11":"tag-unitedstates","12":"tag-us"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/114743091257372725","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/13041","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=13041"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/13041\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/13042"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=13041"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=13041"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=13041"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}