AUG 23, 2017 04:43 PM PDT

Antarctic Microbes Reveal a new Kind of Plasmid

WRITTEN BY: Carmen Leitch

Scientists have discovered a mechanism used by microbes that live in salty lakes in Antarctica to aid growth and survival. Researchers from the University of New South Wales sampled water in remote regions of Antarctica over 18 months, even during winter. Their work revealed a strain of salt-loving microbes that carried a plasmid, a small bit of DNA that can independently replicate inside of a host cell. Often plasmids carry genes that are advantageous to an organism.

Deep Lake in the Vestfold Hills region of Antarctica. The 36-metre deep lake is so salty it remains in liquid form down to a temperature of minus 20 degrees. / Credit: UNSW Sydney

The plasmids found in the Antarctic microbes were a little different than plasmids that are familiar to us. "Unlike viruses, which encase themselves in a protective protein coat, plasmids usually move around by cell to cell contact, or as a piece of naked DNA; but the plasmids that we found in the Antarctic microbes were masquerading as viruses,” explained the research team leader, UNSW scientist Professor Rick Cavicchioli.

These plasmids not only replicated, but they also migrated from their hosts. “They produced proteins which went into the host's membrane, which then allowed the membrane to bud off containing the plasmid DNA,” continued Cavicchioli. “The budded membranes, called membrane vesicles, allowed the plasmids to infect microbes of the same species that did not have any plasmids present, and then replicate themselves in the new host.”

This work has been published in the journal Nature Microbiology. “This is the first time this mechanism has been documented. And it could be an evolutionary forerunner to some of the more structured protective coats that viruses have developed to help them spread and become successful invaders. This finding suggests some viruses may have evolved from plasmids," noted the first author of the report, Dr. Susanne Erdmann.

This is Rauer Island lake in Antarctica. Water samples collected from this remote lake are very rare. / Credit: UNSW Sydney

The microbe described in this work is a type of haloarchaea, which are known to swap genetic material with each other often. The living is easy for these bacteria in Deep Lake, which remains liquid at a cool minus 20 because of its high salt content. Formed around 3500 years ago when the continent of Antarctica rose and trapped a portion of the ocean. Rare samples collected from the Rauer Islands, about 35 kilometers away from the lake, contained the haloarchaea microbes.

"We also discovered that the plasmids could take some of the DNA from the host microbe, integrate it into their own DNA, produce membrane vesicles around themselves, and then go off and infect other cells," said Professor Cavicchioli. "The findings are therefore relevant to Antarctic science as well as biology as a whole."

Learn more about research performed by this team on the salt-loving microbes of Antarctica from the video.

 

Sources: AAAS/Eurekalert! Via University of New South Wales, Nature Microbiology

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
OCT 28, 2018
Genetics & Genomics
OCT 28, 2018
Using Genetics to Learn how Similar Species are Different
Millions of fungal species live all around us; some are a mystery while others have an important role in our world....
NOV 06, 2018
Videos
NOV 06, 2018
Towards a Universal Flu Vaccine
Researchers have to design a new flu vaccine every year. But there are efforts to create a vaccine that works against all strains....
NOV 07, 2018
Videos
NOV 07, 2018
The Threat of Neglected Tropical Diseases
Did you know that around one billion people suffer from a neglected tropical disease?...
NOV 21, 2018
Videos
NOV 21, 2018
The CDC Issues a Serious Warning About All Romaine Lettuce
Don't eat any romaine lettuce, and throw away any you may have at home....
DEC 07, 2018
Microbiology
DEC 07, 2018
Epigenetic Inheritance is Revealed in Archaea
Researchers may have found a great new way to study tags that are added to the genome, which change how genes are expressed....
DEC 09, 2018
Microbiology
DEC 09, 2018
Gut Microbiomes Vary Among Ethnicities
Many products that purport to change the microbiome have entered the market. But first we have to know what a healthy microbiome looks like....
Loading Comments...