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Mutualistic relationship between Nitrospira and concomitant heterotrophs
Chiho Murakami1,2,3, Koshi Machida4, Yoichi Nakao4
1Department of Civil and Environmental Engineering, Graduate School of Engineering Hiroshima University, Hiroshima, Japan.
Environmental Microbiology Reports
|December 4, 2021
Summary
Nitrifying bacteria and heterotrophs form a mutualistic relationship, benefiting each other
Area of Science:
- Microbiology
- Environmental Science
- Biochemistry
Background:
- Nitrifying chemoautotrophs provide organic compounds essential for heterotrophic growth in various environments.
- The ecological roles and interactions between nitrifying bacteria and heterotrophs require further elucidation.
Purpose of the Study:
- To determine if the relationship between nitrifying chemoautotrophs and heterotrophs is commensal or mutualistic.
- To investigate the mechanisms by which heterotrophs promote the growth of autotrophic nitrite-oxidizing bacteria (Nitrospira).
Main Methods:
- Isolation and co-cultivation of heterotrophic bacteria with pure cultures of Nitrospira (Nitrospira sp. ND1).
- Analysis of metabolic by-products and co-cultivation media using liquid chromatography-mass spectrometry (LC-MS).
- Assessment of growth-promoting activity of isolated heterotrophs on Nitrospira.
Main Results:
- Nitrospira growth was significantly stimulated by co-cultivation with specific heterotrophic strains.
- Spent media from certain heterotrophs also promoted Nitrospira growth, indicating the presence of growth factors.
- LC-MS analysis revealed consumption of Nitrospira-produced compounds and the formation of new compounds during co-cultivation.
Conclusions:
- The interaction between Nitrospira and heterotrophs is characterized by a mutualistic relationship, where both partners benefit.
- Certain heterotrophs supply unidentified growth-promoting factors to Nitrospira.
- These mutualistic interactions are crucial for maintaining the stability and diversity of microbial ecosystems.
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