Researchers Unveil Significant Breakthrough in Understanding the Nitrogen Cycle
Researchers from the Max Planck Institute for Marine Microbiology have unveiled a significant breakthrough in the understanding of the nitrogen cycle with the discovery of a unique bacterium. This bacterium, unlike most, uses nitrate to respire within its host, rather than oxygen, revealing adaptive microbial symbioses and their role in the world’s ecosystems.
The discovery, originating from a freshwater lake, pinpointed a bacterium living symbiotically inside a protozoan similar to how mitochondria function within cells. Yet, it distinguishes itself by employing nitrate for its respiratory processes.
Widespread Distribution Across Multiple Regions
The team, intrigued by their initial discovery, scoured vast public gene sequencing records of organisms from various habitats to determine the prevalence of these bacteria. Jana Milucka from the institute noted her astonishment at the ubiquitous nature of these life forms, finding them in environments ranging from groundwater to sewage systems.
Multiple species related to the original endosymbiont were found, expanding the knowledge of symbiotic diversity in nature. Among them, four new species were identified, leading to the classification of two novel genera. Interestingly, some species were observed to survive in oxygen-rich environments due to the presence of a terminal oxidase enzyme.
Collaborative work with Kirsten Küsel and Will Overholt of Friedrich Schiller University permitted an in-depth analysis of these microbes’ gene expression in groundwater, providing insight into their metabolic potential.
Milucka acknowledged the evolutionary implications of the findings, while Daan Speth, the lead author, discussed their environmental influence. The symbiosis these organisms engage in is capable of denitrification, influencing the nitrogen cycle and possibly contributing to the emission of greenhouse gases such as nitrous oxide.
This study, detailed in Nature Communications, spotlights the wonders of microbial symbiosis and its crucial part in the nitrogen cycle, opening vistas to further comprehend eukaryotic evolution and functioning. The study also underscores the complex interconnections that sustain Earth’s life-supporting systems.
