The Evolutionary Secrets of a Newly Discovered Deep-Sea Bacteria

Tuesday - January 16 2024, 00:49 UTC - 10 months ago

A newly discovered species of bacteria at the 'Crab Spa' deep-sea hydrothermal vent offers insights into the evolution and adaptation of bacteria. This mesophilic and sulfur-oxidizing bacteria, named Hydrogenimonas cancrithermarum, expands the known characteristics of its genus and challenges previous assumptions about related bacteria. This discovery emphasizes the crucial role that microbes play in sustaining life at deep-sea hydrothermal vents and their potential impact on other species.

Deep-sea hydrothermal vents, similar to hot springs on the ocean's floor, are a spectacle of nature. These vents, also known as 'Crab Spas', are located deep in the ocean and are a prime location for scientific discovery. Researchers at Hokkaido University, along with colleagues from Woods Hole Oceanographic Institution, have recently discovered a new species of bacteria at the 'Crab Spa' site, offering significant insights into the evolution of bacteria.

In this unique environment, microbes play an essential role in the ecosystem as primary producers. These microbes are able to harness the power of chemosynthesis, similar to how plants on the Earth's surface utilize photosynthesis to convert light into energy. This process is crucial in sustaining life at hydrothermal vents, where sunlight is not available.

The new species of bacteria, named Hydrogenimonas cancrithermarum after the site it was discovered, belongs to the class Campylobacteria, also known as Epsilonproteobacteria. While Campylobacteria are recognized as ecologically important bacteria at hydrothermal vents, some members of this class, such as Helicobacter, Arcobacter, and Campylobacter, are also known to be human and animal pathogens.

The discovery of the mesophilic (adapted to moderate temperatures) Hydrogenimonas species was unexpected as the genus is typically known for being thermophilic (adapted to hot temperatures). This new strain provides researchers with a unique opportunity to study the evolutionary transition from a thermophilic to a mesophilic and from an autotrophic (capable of creating organic compounds) to a heterotrophic (consumes autotrophs to obtain organic compounds) lifestyle.

Additionally, a comparative study of the genomes of related bacteria revealed that the genes responsible for the phosphotransacetylase-acetate kinase (Pta-AckA) pathway tend to be conserved between Hydrogenimonas and mesophilic species that diverged from it, regardless of their metabolism and pathogenicity. The Pta-AcK pathway was previously thought to only be involved in energy metabolism and colonization in pathogenic Campylobacteria, but this discovery suggests it may also play a role in acetate assimilation for Hydrogenimonas.

This new species of bacteria is significant in understanding the evolution and adaptation of bacteria in diverse environments. It also sheds light on the crucial role that bacteria play in sustaining life at deep-sea hydrothermal vents, and their potential for both positive and negative effects on other organisms. With further research, Hydrogenimonas cancrithermarum will continue to reveal secrets of the deep sea and add to our understanding of this unique ecosystem.