AUG 23, 2017 4:43 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
MAY 05, 2020
Immunology
Winter the Llama: An Unlikely Hero in the Fight Against COVID-19
MAY 05, 2020
Winter the Llama: An Unlikely Hero in the Fight Against COVID-19
A new hero in the fight against COVID-19 has emerged: 4-year-old Winter, a llama that currently resides in the Belgian c ...
MAY 20, 2020
Microbiology
How a Microbe Can Help Us Tackle Food Waste
MAY 20, 2020
How a Microbe Can Help Us Tackle Food Waste
Food waste is a major problem. A recent study conducted over seven years concluded that the average American wastes one ...
MAY 31, 2020
Microbiology
Zika Virus Infections in Early Life Can Cause Brain Damage
MAY 31, 2020
Zika Virus Infections in Early Life Can Cause Brain Damage
The Zika virus, which is transmitted by Aedes mosquitoes, poses significant risks to the developing fetus, and new work ...
JUN 08, 2020
Microbiology
Concerns Remain About the Accuracy of COVID-19 Tests
JUN 08, 2020
Concerns Remain About the Accuracy of COVID-19 Tests
Diagnostic tests have recently been getting a lot of attention because of the COVID-19 pandemic.
JUL 07, 2020
Microbiology
Why Some Are Naturally Better at Preventing Urinary Tract Infections
JUL 07, 2020
Why Some Are Naturally Better at Preventing Urinary Tract Infections
Urinary tract infections can be very painful and can cause nausea, chills, and fever. A pathogenic strain of E. coli is ...
JUL 26, 2020
Microbiology
Ongoing Salmonella Outbreak Rapidly Spreads to 23 States
JUL 26, 2020
Ongoing Salmonella Outbreak Rapidly Spreads to 23 States
The CDC has announced that an outbreak of infections related to a strain of the bacterium Salmonella is "rapidly growing ...
Loading Comments...