Environmental and Life Science Graduate Program, Trent University, Peterborough, ON, Canada.
Forensic Science Department, Trent University, Peterborough, ON, Canada.
Int Microbiol. 2024 Aug;27(4):1249-1268. doi: 10.1007/s10123-023-00474-7. Epub 2024 Jan 3.
Synthetic algal-fungal and algal-bacterial cultures have been investigated as a means to enhance the technological applications of the algae. This inclusion of other microbes has enhanced growth and improved stress tolerance of the algal culture. The goal of the current study was to investigate natural microbial consortia to gain an understanding of the occurrence and benefits of these associations in nature. The photosynthetic protist Euglena mutabilis is often found in association with other microbes in acidic environments with high heavy metal (HM) concentrations. This may suggest that microbial interactions are essential for the protist's ability to tolerate these extreme environments. Our study assessed the Cd tolerance of a natural fungal-algal-bacterial (FAB) association whereby the algae is E. mutabilis.
This study provides the first assessment of antibiotic and antimycotic agents on an E. mutabilis culture. The results indicate that antibiotic and antimycotic applications significantly decreased the viability of E. mutabilis cells when they were also exposed to Cd. Similar antibiotic treatments of E. gracilis cultures had variable or non-significant impacts on Cd tolerance. E. gracilis also recovered better after pre-treatment with antibiotics and Cd than did E. mutabilis. The recoveries were assessed by heterotrophic growth without antibiotics or Cd. In contrast, both Euglena species displayed increased chlorophyll production upon Cd exposure. PacBio full-length amplicon sequencing and targeted Sanger sequencing identified the microbial species present in the E. mutabilis culture to be the fungus Talaromyces sp. and the bacterium Acidiphilium acidophilum.
This study uncovers a possible fungal, algal, and bacterial relationship, what we refer to as a FAB consortium. The members of this consortium interact to enhance the response to Cd exposure. This results in a E. mutabilis culture that has a higher tolerance to Cd than the axenic E. gracilis. The description of this interaction provides a basis for explore the benefits of natural interactions. This will provide knowledge and direction for use when creating or maintaining FAB interactions for biotechnological purposes, including bioremediation.
合成藻菌和藻菌培养物已被研究作为增强藻类技术应用的一种手段。这种其他微生物的加入促进了藻类培养物的生长并提高了其对压力的耐受性。目前研究的目的是研究自然微生物群落，以了解这些关联在自然界中的发生和益处。光合原生动物变形虫通常在酸性环境中与其他微生物一起存在，这些环境具有高重金属（HM）浓度。这可能表明微生物相互作用对于原生动物耐受这些极端环境的能力至关重要。我们的研究评估了一种天然真菌-藻类-细菌（FAB）共生体中变形虫的 Cd 耐受性，其中藻类是变形虫。
本研究首次评估了抗生素和抗真菌剂对变形虫培养物的影响。结果表明，当变形虫细胞同时暴露于 Cd 时，抗生素和抗真菌剂的应用会显著降低其细胞活力。抗生素对 E. gracilis 培养物的类似处理对 Cd 耐受性有不同或无显著影响。与变形虫相比，E. gracilis 在抗生素和 Cd 预处理后恢复得更好。在没有抗生素或 Cd 的情况下通过异养生长来评估回收率。相比之下，两种 Euglena 物种在暴露于 Cd 后均增加了叶绿素的产生。PacBio 全长扩增子测序和靶向 Sanger 测序确定了变形虫培养物中存在的微生物物种是真菌 Talaromyces sp.和细菌 Acidiphilium acidophilum。
本研究揭示了一种可能的真菌、藻类和细菌关系，我们称之为 FAB 共生体。该共生体的成员相互作用，增强了对 Cd 暴露的反应。这导致变形虫培养物对 Cd 的耐受性高于纯种的 E. gracilis。这种相互作用的描述为探索自然相互作用的益处提供了基础。这将为在生物技术应用（包括生物修复）中创建或维持 FAB 相互作用提供知识和方向。
