Luu Gordon T, Little Jessica C, Pierce Emily C, Morin Manon, Ertekin Celine A, Wolfe Benjamin E, Baars Oliver, Dutton Rachel J, Sanchez Laura M
Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California, 95064.
Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, Illinois, 60612.
bioRxiv. 2023 Mar 13:2023.03.13.532449. doi: 10.1101/2023.03.13.532449.
Bacterial-fungal interactions (BFIs) can shape the structure of microbial communities, but the small molecules mediating these BFIs are often understudied. We explored various optimization steps for our microbial culture and chemical extraction protocols for bacterial-fungal co-cultures, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed that metabolomic profiles are mainly comprised of fungi derived features, indicating that fungi are the key contributors to small molecule mediated BFIs. LC-inductively coupled plasma MS (LC-ICP-MS) and MS/MS based dereplication using database searching revealed the presence of several known fungal specialized metabolites and structurally related analogues in these extracts, including siderophores such as desferrichrome, desferricoprogen, and palmitoylcoprogen. Among these analogues, a novel putative coprogen analogue possessing a terminal carboxylic acid motif was identified from spp. JB370, a common cheese rind fungus, and its structure was elucidated via MS/MS fragmentation. Based on these findings, filamentous fungal species appear to be capable of producing multiple siderophores with potentially different biological roles (i.e. various affinities for different forms of iron). These findings highlight that fungal species are important contributors to microbiomes via their production of abundant specialized metabolites and their role in complex communities should continue to be a priority.
细菌 - 真菌相互作用(BFIs)能够塑造微生物群落的结构,但介导这些BFIs的小分子往往研究不足。我们探索了用于细菌 - 真菌共培养的微生物培养和化学提取方案的各种优化步骤,液相色谱 - 串联质谱(LC-MS/MS)显示代谢组学图谱主要由真菌衍生特征组成,这表明真菌是小分子介导的BFIs的关键贡献者。液相色谱 - 电感耦合等离子体质谱(LC-ICP-MS)以及基于数据库搜索的MS/MS去重复分析揭示了这些提取物中存在几种已知的真菌特殊代谢产物及其结构相关类似物,包括铁载体如去铁胺、去铁铁载体和棕榈酰铁载体。在这些类似物中,从常见的奶酪外皮真菌spp. JB370中鉴定出一种具有末端羧酸基序的新型推定铁载体类似物,并通过MS/MS碎片分析阐明了其结构。基于这些发现,丝状真菌似乎能够产生多种具有潜在不同生物学作用(即对不同形式铁的各种亲和力)的铁载体。这些发现突出表明,真菌物种通过产生丰富的特殊代谢产物对微生物群落做出重要贡献,并且它们在复杂群落中的作用应继续作为优先研究对象。