The marine bone biome is a complex assemblage of macro- and microorganisms; however, the enzymatic repertoire to access bone-derived nutrients remains unknown. The bone matrix is a composite material made up mainly of organic collagen and inorganic hydroxyapatite. We conducted field experiments to study microbial assemblages that can use organic bone components as nutrient source. Bovine and turkey bones were deposited at 69 m depth in a Norwegian fjord (Byfjorden, Bergen). Metagenomic sequence analysis was used to assess the functional potential of microbial assemblages from bone surface and the bone-eating worm Osedax mucofloris, which is a frequent colonizer of whale falls and known to degrade bone. The bone microbiome displayed a surprising taxonomic diversity revealed by the examination of 59 high-quality metagenome-assembled genomes from at least 23 bacterial families. Over 700 genes encoding enzymes from 12 relevant enzymatic families pertaining to collagenases, peptidases, and glycosidases putatively involved in bone degradation were identified. Metagenome-assembled genomes (MAGs) of the class Bacteroidia contained the most diverse gene repertoires. We postulate that demineralization of inorganic bone components is achieved by a timely succession of a closed sulfur biogeochemical cycle between sulfur-oxidizing and sulfur-reducing bacteria, causing a drop in pH and subsequent enzymatic processing of organic components in the bone surface communities. An unusually large and novel collagen utilization gene cluster was retrieved from one genome belonging to the gammaproteobacterial genus Colwellia.

中文翻译：

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破译海洋骨降解微生物组揭示了复杂的社区努力

海洋骨骼生物群落是宏观生物和微生物的复杂组合。然而，获取骨源性营养物质的酶谱仍然未知。骨基质是以有机胶原蛋白和无机羟基磷灰石为主要成分的复合材料。我们进行了现场实验来研究可以使用有机骨成分作为营养源的微生物组合。牛骨和火鸡骨沉积在挪威峡湾（卑尔根 Byfjorden）69 m 深处。宏基因组序列分析用于评估骨骼表面微生物组合和食骨蠕虫粘花骨蠕虫的功能潜力，粘虫骨蠕虫是鲸鱼坠落的常见定植者，已知会降解骨骼。通过对来自至少 23 个细菌家族的 59 个高质量宏基因组组装基因组的检查，揭示了骨微生物组显示出令人惊讶的分类多样性。鉴定了来自 12 个相关酶家族的 700 多个编码酶的基因，这些酶家族涉及推测与骨降解有关的胶原酶、肽酶和糖苷酶。拟杆菌类的宏基因组组装基因组（MAG）包含最多样化的基因库。我们假设，无机骨成分的脱矿质是通过硫氧化细菌和硫还原细菌之间及时连续的封闭硫生物地球化学循环来实现的，导致pH值下降以及随后骨表面群落中有机成分的酶处理。从属于伽马变形菌属Colwellia的一个基因组中检索到一个异常大且新颖的胶原蛋白利用基因簇。