Diverse abundant populations of the bacterium that produces the well-known sexually transmitted infection chlamydia, have been discovered in deep sediments of the Arctic Ocean.
These nuclei of Chlamydia trachomatis live in oxygen deprived conditions, at high pressure and without an apparent host organism. Their study, published in Current Biology, provides new insights into how chlamydia became human and animal pathogens.
Chlamydia and related bacteria, collectively called Chlamydiae, and all of the studied members of this group depend on interactions with other organisms to survive. Chlamydiae specifically interact with organisms like animals, plants and fungi, and include microscopic organisms such as amoebae, algae, and plankton.
Chlamydiae spend much of their lives inside the cells of their hosts, humans, but also bears and koalas. Most of the knowledge about Chlamydiae is based on studies of pathogenic lineages in the laboratory. But do chlamydiae also exist in other settings? New research published in ‘Current Biology’ shows that Chlamydiae can be found in the most unexpected places.
An international group of researchers reports the discovery of numerous new species of Chlamydiae that grow in deep sediments of the Arctic Ocean, in the absence of obvious host organisms.
The researchers had been exploring microbes that live more than 3 km below the ocean surface and several meters in the sediment of the ocean floor during an expedition to Loki Castle, a hydrothermal ventilation field of deep water located in the Arctic Ocean between Iceland, Norway, and Svalbard. This environment lacks oxygen and macroscopic life forms.
Unexpectedly, the research team found very abundant and diverse Chlamydia relatives. “Finding Chlamydiae in this environment it was completely unexpected and of course raised the question of what the hell were they doing there, “says Jennah Dharamshi of Uppsala University in Sweden and lead author of the study, in a statement.
The team of researchers had been working with metagenomic data, obtained through the collective sequence of genetic material from all organisms that live in an environment that does not depend on growing organisms in the laboratory. “The vast majority of life on earth is microbiana, and currently most cannot be grown in the laboratory, “explains Thijs Ettema, professor of microbiology at Wageningen University and Research in the Netherlands who led the work.
“By using genomic methods, we got a clearer picture of the diversity of life. Every time we explore a different environment, we discover clusters of microbes that are new to science. This tells us how much remains to be discovered.”