小柯机器人

美国加州大学伯克利分校Jillian F. Banfield研究组发现，Borg是具有扩大新陈代谢潜力的巨大遗传元件。这一研究成果于2022年10月19日在线发表在国际学术期刊《自然》上。

研究人员通过研究甲烷生产和氧化发生的地下水、沉积物和湿地土壤，发现了特别大的、多样化的DNA序列，主要编码假设的蛋白质。四个经过校正的完整基因组是线性的，长度可达约1Mb，并共享基因组组织，包括复制体结构、长的倒置末端重复和全基因组独特的完美串联直接重复，这些是基因间或产生氨基酸的重复。

研究人员推断，这些是高度分化的古细菌染色体外元件，具有不同的演化起源。基因序列的相似性、系统发育和序列组成的局部分歧表明，它们的许多基因是从甲烷氧化的Methanoperedens古菌中同化而来的。研究人员把这些元件称为“Borg”。研究人员发现至少有19种不同的Borg类型与Methanoperedens属共存于四个不同的生态系统中。Borg为甲烷氧化型Methanoperedens古菌提供了获得编码参与氧化还原反应和能量保存的蛋白质的基因的途径（例如，多血红素细胞色素和甲基辅酶M还原酶的簇）。

这些数据表明，Borg可能在这组古菌的新陈代谢中具有以前未被认识到的作用，这些古菌已知可以调节温室气体排放，但现在需要进一步研究来确定其功能相关性。

据介绍，厌氧甲烷氧化对温室气体排放起着关键的控制作用，然而，对执行这一功能的微生物活动的调节因素仍然知之甚少。

附：英文原文

Title: Borgs are giant genetic elements with potential to expand metabolic capacity

Author: Al-Shayeb, Basem, Schoelmerich, Marie C., West-Roberts, Jacob, Valentin-Alvarado, Luis E., Sachdeva, Rohan, Mullen, Susan, Crits-Christoph, Alexander, Wilkins, Michael J., Williams, Kenneth H., Doudna, Jennifer A., Banfield, Jillian F.

Issue&Volume: 2022-10-19

Abstract: Anaerobic methane oxidation exerts a key control on greenhouse gas emissions1, yet factors that modulate the activity of microorganisms performing this function remain poorly understood. Here we discovered extraordinarily large, diverse DNA sequences that primarily encode hypothetical proteins through studying groundwater, sediments and wetland soil where methane production and oxidation occur. Four curated, complete genomes are linear, up to approximately 1Mb in length and share genome organization, including replichore structure, long inverted terminal repeats and genome-wide unique perfect tandem direct repeats that are intergenic or generate amino acid repeats. We infer that these are highly divergent archaeal extrachromosomal elements with a distinct evolutionary origin. Gene sequence similarity, phylogeny and local divergence of sequence composition indicate that many of their genes were assimilated from methane-oxidizing Methanoperedens archaea. We refer to these elements as ‘Borgs’. We identified at least 19 different Borg types coexisting with Methanoperedens spp. in four distinct ecosystems. Borgs provide methane-oxidizing Methanoperedens archaea access to genes encoding proteins involved in redox reactions and energy conservation (for example, clusters of multihaem cytochromes and methyl coenzyme M reductase). These data suggest that Borgs might have previously unrecognized roles in the metabolism of this group of archaea, which are known to modulate greenhouse gas emissions, but further studies are now needed to establish their functional relevance.

DOI: 10.1038/s41586-022-05256-1

Source: https://www.nature.com/articles/s41586-022-05256-1

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html